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'''1st MC Meeting, [[COST Action MitoEAGLE]], Brussels, BE''' +
'''2017 Jul 23-30, Obergurgl, AT.''' +
'''2017 Jul 27-30, Obergurgl, AT.''' +
'''AussieMit 2016, Sydney, AU''' +
'''Bioenergetics Vienna''', 1st Bioenergetics DE-CH-AT Meeting +
'''Brain bioenergetics – From behavior to pathology, Lausanne, CH''' +
'''COST MitoEAGLE WG and MC Meeting, 2019, Belgrade, Serbia.''' +
'''Demo O2k-Course at MiPsummer 2009.''' Baton Rouge, USA; 2009 June 21. +
'''ESCI meeting, Genoa, IT''' +
'''FASEB, West Palm Beach, FL, US''' +
'''FAT4BRAIN 1st Online ESR Workshop, 2020''' +
'''FAT4BRAIN 2nd Online ESR Workshop, 2021''' +
'''FAT4BRAIN 3rd Online ESR Workshop, 2022''' +
'''FAT4BRAIN 4th Online ESR Workshop, 2022''' +
'''FAT4BRAIN ESR Workshop, 2023''' +
'''FAT4BRAIN Final rview meeting, Virtual, 2023''' +
'''FAT4BRAIN Kick-off meeting, Riga, Latvia, 2019''' +
'''FAT4BRAIN Midterm Review meeting, Virtual, 2021''' +
'''MiP2023, Obergurgl, Austria, 2023.''' +
'''Mitochondrial Medicine 2017, Washington DC, USA.''' +
'''Oroboros Distributor Meeting'''. Virtual. +
'''Oroboros Installation and startup support session'''. +
'''Oroboros O2k-Workshop on high-resolution respirometry'''. +
'''Research to Practice 2016, Singapore, SG''' +
"Hofstadter has emphasized that Gödel, Esc … "Hofstadter has emphasized that Gödel, Escher, Bach is not about the relationships of mathematics, art, and music, but rather about how cognition emerges from hidden neurological mechanisms. At one point in the book, he presents an analogy about how the individual neurons of the brain coordinate to create a unified sense of a coherent mind by comparing it to the social organization displayed in a colony of ants." - Wikipediaisplayed in a colony of ants." - Wikipedia +
"What is the O2 concentration in a normoxi … "What is the O2 concentration in a normoxic cell culture incubator?" This and other frequently asked questions in hypoxia research will be answered in this review. Our intention is to give a simple introduction to the physics of gases that would be helpful for newcomers to the field of hypoxia research. We will provide background knowledge about questions often asked, but without straightforward answers. What is O2 concentration, and what is O2 partial pressure? What is normoxia, and what is hypoxia? How much O2 is experienced by a cell residing in a culture dish in vitro vs in a tissue in vivo? By the way, the O2 concentration in a normoxic incubator is 18.6%, rather than 20.9% or 20%, as commonly stated in research publications. And this is strictly only valid for incubators at sea level.ly only valid for incubators at sea level. +
# A Mg2+-dependent … # A Mg2+-dependent adenosine triphosphatase was solubilized and purified from bakers' yeast mitochondria. The enzyme resembled mitochondrial ATPase from beef heart with respect to substrate specificity, cold lability, and other physical properties.# An antiserum against the purified yeast enzyme inhibited the ATPase activity of the soluble enzyme as well as ATPase and oxidative phosphorylation in submitochondrial yeast particles. Mitochondrial ATPase from beef heart or from Neurospora crassa was not inhibited by the antiserum. # Submitochondrial beef heart particles devoid of endogenous ATPase could bind the purified yeast enzyme without changing its immunological specificity. The ATPase activity of the resultant "hybrid" particles, like that of beef heart particles, was strongly inhibited by low levels of rutamycin. In contrast, submitochondrial particles from yeast were much less sensitive to this inhibitor. # The yeast enzyme stimulated oxidative phosphorylation in beef heart particles which were deficient in, but not devoid of, endogenous ATPase. The stimulation was dependent on the presence of beef heart coupling factor 1 (F1) in these particles and was unaffected by the antiserum against the yeast enzyme. Antiserum against beef heart F1 strongly inhibited phosphorylation. These results suggest that yeast F1, in contrast to beef heart F1, does not significantly participate in phosphate transfer reactions when it functions as a coupling factor in beef heart particles. Rather, it is proposed that the stimulation by yeast F1 is due to an effect on the membrane structure.yeast F1 is due to an effect on the membrane structure. +
# A specific succinate requirement for en … # A specific succinate requirement for energy-linked reduction of mitochondrial pyridine nucleotide is demonstrated in pigeon heart and guinea pig kidney mitochondria.# The succinate used in this reduction can be generated in the oxidation of malate plus glutamate or of α-ketoglutarate. # The role of succinate is identified by the specific inhibitory responses of the reaction to malonate, phosphate, and fumarate. # At least two kinds of mitochondrial pyridine nucleotide are shown to be reducible in State 4: (a) about one-third in the absence of added succinate in a malonate-insensitive reaction in the presence of a substrate such as malate plus glutamate and (b) about two-thirds in the presence of added succinate in a malonate-sensitive, energy-linked reaction. These two kinds of pyridine nucleotide may be considered to be compartmented.tide may be considered to be compartmented. +
# Aus Saeugetierlebern lassen sich Suspen … # Aus Saeugetierlebern lassen sich Suspensionen kleiner, Brown'sche Bewegung zeigender Koernchen gewinnen, die Sauerstoff verbrauchen und Kohlensaeure bilden. Die Oxydationsgroesse war etwa 1/5 der Oxydationsgroesse der entsprechenden Menge intakten Lebergewebes, wenn der Masing'sche Mittelwert von 1200 ccm pro Kilo und Stunde der Vergleichsrechnung zugrunde gelegt wird. Die Koernchen sind wahrscheinlich identisch mit den praeformierten Lebergranula.# Aus Saeugetierlebern lassen sich mittels Filtration durch Berkefeld-Kerzen Fluessigkeiten gewinnen, die Sauerstoff verbrauchen und Kohlensaeure bilden. Die Oxydationsgroesse war etwa 4% von der Oxydationsgroesse der entsprechenden Menge intakten Lebergewebes. Filtratatmung und Zellatmung stehen, der Groessenordnung nach, in aehnlichem Verhaeltnis zueinander wie die Buchnersche Presssaftgaerung zur Hefezellengaerung.# Die akzessorische oder wasserloesliche Atmung aus frischem Lebergewebe, die Batelli und Stern beschrieben haben, ist wahrscheinlich zum groesseren Teil Koernchenatmung. Ein kleiner Teil ist auf Rechnung der Zwischenfluessigkeit zu setzen und kann in der ueblichen Terminologie als wasserloesliche Atmung bezeichnet werden.# Die Atmung intakter, aus dem Koerper entfernter Leberlaeppchen bleibt stundenlang konstant. Die Labilitaet der Atmung der intakten Zellen — der sogenannten Hauptatmung — wird bei der Versuchsanordnung von Batelli und Stern vorgetaeuscht durch Schaedigungen, die die Lebern infolge von Sauerstoffmangel erleiden.bern infolge von Sauerstoffmangel erleiden. +
# Estimations of the carbohydrate metabol … # Estimations of the carbohydrate metabolism of several strains of mouse tumours are recorded. Great deviations from the standard values found for tumours of rat, fowl and a limited series of human tumours were observed in many cases. Wide variations are shown to occur between tumours of different strains, and also between members of the same strain. The most noticeable feature is the number of cases of high respiration, both in its absolute value and also in its relation to the aerobic and anaerobic glycolysis. This respiration is ineffective in checking the aerobic glycolysis, its activity in this direction being, in some cases, less than 10% of that found in the case of working muscle, and in many mammalian tumours. Some factors which might operate in causing these variations are changes in the respiratory quotient, differences of environment during growth, efficiency of blood supply, and the generally higher metabolic rate of the mouse as compared with larger animals.# A manometric method for the simultaneous measurement of the carbohydrate metabolism and the respiratory quotient is briefly described, based on the fact that the glycolysis effected by tumour tissue is a pure lactic fermentation. The respiratory quotients with one exception were found to be below unity. This would tend to make the actual aerobic glycolysis relatively higher than that usually recorded, since the assumption has hitherto been made that a respiratory quotient of unity would result from the experimental conditions. The results again illustrate the ineffectiveness of respiration in checking glycolysis.# Xylose is not metabolised by tumour tissue.# Evidence is brought forward which suggests that the glycolytic activity of tumours exerts a checking effect on their respiration.# The carbohydrate metabolism of tumours is to some extent influenced by the environment in which they grow. This is demonstrated by the study of two series of Jensen's rat sarcomata, simultaneously transplanted, one series subcutaneously and the other intraperitoneally. The respiration of the subcutaneous growths was, on the average, 50% higher than that of the intraperitoneal growths. The majority of these subcutaneous tumours do not exhibit a positive value for the excess fermentation, which was, until recently, regarded by Warburg as a criterion for the metabolism of tumour tissue. The correlation of these differences with the normal tissue tensions of CO2 and 02 iS difficult. Campbell found the oxygen tension in the abdominal cavity 50% higher than under the skin, the CO2 tensions being approximately the same. The higher respiration found in these two series of tu-mours corresponds to the lower 02 tension in the surrounding tissues, and vice versa. It is obvious that other factors which have not yet been analysed are operative. The general result of these observations is to emphasise the difficulty of including the wide variations found in the carbohydrate metabolism of tumour tissue in one generalisation. The constant factor is the possession of a high aerobic glycolysis, which, though not specific for tumour tissue, is a source of energy available for uncontrolled ptoliferation.y available for uncontrolled ptoliferation. +
# Mechanically fragmented beef heart … # Mechanically fragmented beef heart mitochondria have been resolved by differential centrifugation into a particulate and a soluble protein component, both of which were required for oxidative phosphorylation. The particulate fraction alone catalyzed the oxidation of succinate, β-hydroxybutyrate, isocitrate, and glutamate with little or no concomitant phosphorylation. Addition of the soluble factor to the particles resulted in a net uptake of inorganic phosphate with a P:O of 0.4 to 0.8. Similarly, both fractions were required for a P32-ATP exchange. # The highly purified, soluble coupling factor catalyzed a dinitrophenol-stimulated hydrolysis of ATP. # Comparative studies of the cold lability, heat stability, and other physical properties strongly favored the conclusion that the coupling and ATPase activity were catalyzed by the same protein. # The significance of these results in relation to current concepts of the mechanism of oxidative phosphorylation has been discussed.tive phosphorylation has been discussed. +
# Submitochondrial particles have been se … # Submitochondrial particles have been sequentially treated with trypsin, urea, and sonic oscillation at an alkaline pH. These TUA particles required addition of a protein (Fc1) in order to render added ATPase (F1) sensitive to dicyclohexylcarbodiimide. Further resolution was obtained by exposure of TUA particles either to 2 M sodium thiocyanate or to 1.5% silicotungstate. These procedures removed a second soluble protein component (Fc2) which was also required for the sensitivity of ATPase to dicyclohexylcarbodiimide.# Preparations of Fc2 purified from the sodium thiocyanate extract stimulated the 32Pi-ATP exchange reaction and oxidative phosphorylation in silicotungstate-treated submitochondrial particles.# Treatment of TUA particles with silicotungstate reduced their ability to bind ATPase (F1). Addition of Fc2 restored the ability to bind ATPase. It is therefore proposed that Fc2 is a component which links the mitochondrial ATP-ase to the inner mitochondrial membrane.TP-ase to the inner mitochondrial membrane. +
# Succinic dehydrogenase has been iso … # Succinic dehydrogenase has been isolated from beef heart mitochondria as a soluble protein in a state approaching homogeneity by physico-chemical criteria. The overall purification is about 100-fold compared with a mitochondrial acetone powder. # The enzyme is a ferroflavoprotein cont,aining 4 atoms of ferrous (non-hemin) iron and a mole of flavin per mole of protein (200,000 gm.). The dehydrogenase may be isolated from aged starting material with 2 atoms of iron per mole and half the specific activity. # Among the common electron acceptors, only the following function with the dehydrogenase, at the relative rates indicated in parentheses: phenazine methosulfate (100), ferricyanide (39), O2 (0.02). The first two of these acceptors react via the iron moieties, whereas O2 seems to react directly with the flavin. # The QO2, has been measured as 20,000 and the turnover number as 3000 under the standard assay conditions. # The properties of the isolated dehydrogenase agree with those previously described for mitochondrial and other particulate preparations of the enzyme, except for properties related to the absence of contaminating hemoproteins. At 38 °C the pH optimum is 7.7; the K, for succinate is 1.3 X 10-3 M at 38 °C and 5.2 X 10-4 M at 21 °C. Oxalacetate, malonate, and fumarate are competitive inhibitors. Antimycin A and BAL do not inhibit the dehydrogenase. The dehydrogenase is highly sensitive to sulfhydryl reagents, p-chloromercuribenzoate inhibiting it in a reversible manner and the substrate protecting the enzyme from this type of inhibition. enzyme from this type of inhibition. +
# The pathway of electron transfer f … # The pathway of electron transfer from succinate to pyridine nucleotide shows a sensitivity to antimycin A, suggesting that carriers of the respiratory chain up to and including the antimycin-sensitive point are involved in succinate-linked reduction of pyridine nucleotide.# The sensitivity of succinate-linked reduction of pyridine nucleotide to Amytal suggests that a reverse of the flavoprotein-pyridine nucleotide interaction observed in the oxidation of pyridine nucleotide in phosphorylating mitochondria is also part of the electron transfer pathway. # Mechanisms indicating the interconnection of electrons from the antimycin-sensitive point to this flavoprotein via electron carriers such as cytochrome b and ubiquinone are considered. These mechanisms appear to apply to both aerobic and anaerobic (terminally inhibited) energy-linked reduction of pyridine nucleotide. # Three mechanisms for increased reduction of pyridine nucleotide in succinate-treated mitochondria that do not involve the above pathway fail to show responses of the experimentally observed sensitivity to Amytal or to antimycin A. # The properties of the energy-linked pool of pyridine nucleotide in metabolism are considered. Its participation is likely to be small in state 3 and of some consequence in state 4. and of some consequence in state 4. +
# The purification o f a soluble ATP … # The purification o f a soluble ATPase from beef heart mitochondria is described. The activity is dependent on Mg++ and is stimulated by 2,4-dinitrophenol. The enzyme cleaves the terminal phosphate of ATP and is inhibited by ADP. The activity is therefore assayed in the presence of an ATP regenerating system. # The enzyme is cold labile. Although stable at room temperature, the enzyme rapidly loses activity at 4°. ATP, which protects the enzyme against inactivation by heat and dialysis, does not prevent the cold inactivation. # Attempts to demonstrate an exchange between either Pi32 or C14-ADP and ATP in the presence of the enzyme were unsuccessful. # The properties of the purified enzyme are discussed in relation to particulate mitochondrial ATPase and to myosin ATPase.ochondrial ATPase and to myosin ATPase. +
# The ability to phosphorylate ADP during … # The ability to phosphorylate ADP during oxidation of NADH by ubiquinone-1 was restored to the NADH-ubiquinone reductase complex by combining the latter with phospholipids and a hydrophobic protein fraction derived from bovine heart mitochondria.# Phosphorylation was abolished by rotenone, uncoupling agents, or rutamycin. The efficiency of ATP formation was as high as 0.5 mole per mole of NADH oxidized under optimal conditions.# Reconstitution of phosphorylation had an absolute requirement for phosphatidylethanolamine and a partial requirement for phosphatidylcholine, a molar ratio of approximately 4:1 being optimal. A much more marked requirement for phosphatidylcholine was observed in the presence of low concentrations of cardiolipin (0.05 to 1.5% of the total phospholipid). In the presence of cardiolipin, an equal molar ratio of phosphatidylethanolamine to phosphatidylcholine gave the highest phosphorylation efficiency.# The NADH-ubiquinone reductase complex is oriented in the reconstituted vesicles such that approximately 50% of the molecules can react with added NADH. Reaction of all the molecules with NADH occurs in the presence of 0.5% deoxycholate.# Phosphorylation efficiency can be significantly improved by purification of the vesicles on sucrose density gradients. the vesicles on sucrose density gradients. +
# The reduction of added DPN by succinate … # The reduction of added DPN by succinate catalyzed by submitochondrial particles from beef heart has been studied.# The reduction was endergonic and required specifically the addition of ATP.# The reaction had a limited specificity for electron acceptors; six DPN analogues tested were reduced at the same rate or nearly the same rate, as was DPN. TPN was only reduced at a very slow rate.# The rate of reduction was influenced by phosphate and ADP and their effects became pronounced if added together.# The effect of DPNH was marked only if added in a concentration equal to or exceeding that of DPN.# Respiratory inhibitors acting in the flavin region of the respiratory chain blocked the reaction.the respiratory chain blocked the reaction. +
# The α-ketoglutaric oxidase system of he … # The α-ketoglutaric oxidase system of heartmuscle sarcosomes has a pH optimum at 7.4. The yield of oxidative phosphorylation (P:O ratio) is unchanged between pH 6.2 and 7.7.# Hypertonic sucrose (0.88 M) is an inhibitor of the succinic oxidase system in the Keilin & Hartree preparation. Its major effect appears to be on the accessibility of both the endogenous and added cytochrome ''c'' to the other components of the system.# Maximum activity of the α-ketoglutaric oxidase system of heart-muscle sarcosomes is obtained under the most highly hypotonic conditions studied, equivalent to about one-third isotonic. Under these conditions, sarcosomes are swollen, but shrink again when placed in isotonic medium. The effect of tonicity on the activity of the α-ketoglutaric oxidase system is also reversible. # As the tonicity is increased by saline, sucrose or phosphate, the activity of the α-ketoglutaric oxidase system decreases.# The P:O ratio is not affected over a wide range of sucrose concentrations which have a marked effect on the activity of the α-ketoglutaric oxidase system. This and other examples where the oxidase system is more sensitive than the P:O ratio to variations of the conditions indicates that the phosphorylative enzymes are normally in excess of the purely oxidative enzymes and increases the likelihood that measurements of the yield of oxidative phosphorylation on isolated tissue preparations represent the state of affairs in the cell. # Phosphate, in high concentration, decreases the P:O ratio; the optimal concentration is 0.03 M. # Hypertonic sucrose is unsuitable for the isolation of sarcosomes. There is, however, no significant difference between sarcosomes isolated with isotonic sucrose and isotonic saline, except that the latter are deficient in cytochrome ''c''.t the latter are deficient in cytochrome ''c''. +
# [[Mitochondrial marker enzymes|Marker enzymes]] … # [[Mitochondrial marker enzymes|Marker enzymes]] for the mitochondrial matrix, inner membrane, inter-membrane space and outer membrane were measured in mitochondria isolated from control and regenerating rat liver. The specific activity of these enzymes was then followed for up to 30 days after operation. # The specific activity of marker enzymes for the matrix, inner membrane and inter-membrane space remained constant during liver regeneration.# However, the specific activities of monoamine oxidase and kynurenine hydroxylase, both outer-membrane markers, fell by 67% and 49% respectively from their control values at 4 days after operation, and returned to normal by about 3 weeks.# The repression of kynurenine hydroxylase activity was shown to be unrelated to any independent variation in tryptophan catabolism, based on tryptophan pyrrolase assays.# These results are considered to indicate that enzymes of the inner and outer mitochondrial membranes are synthesized asynchronously during morphogenesis.# The enzyme complement of purified outer membrane at 4 days after operation was about 50% of that of the appropriate control. Thus the composition of the outer membrane itself may vary dramatically, and supports the concept that constitutive enzymes may turn over independently of a membrane's existence.# The behaviour of the rotenone-insensitive, NADH cytochrome c reductase did not parallel the other outer-membrane enzymes for intact mitochondria, but did so when assayed in highly purified fractions of outer membrane. This suggests a labile binding to the outer membrane during the early stages of morphogenesis.# Electrophoresis of inner- and outer-membrane proteins revealed little difference between control and experimental mitochondria at 4 days, except for an increase in several, high-molecular-weight components of the outer membrane. These bands closely correspond to similar bands derived from smooth endoplasmic reticulum.# The results are discussed in relation to the biogenesis and turnover of mitochondria, and are considered to provide evidence for turnover as a unit, at least for the matrix, inner membrane, inter-membrane space and possibly some form of primary outer membrane.ssibly some form of primary outer membrane. +
'''''Significance:''''' Oxygen is indispen … '''''Significance:''''' Oxygen is indispensable for aerobic life, but its utilization exposes cells and tissues to oxidative stress; thus, tight regulation of cellular, tissue, and systemic oxygen concentrations is crucial. Here, we review the current understanding of how the human organism (mal-)adapts to low (hypoxia) and high (hyperoxia) oxygen levels and how these adaptations may be harnessed as therapeutic or performance enhancing strategies at the systemic level. '''''Recent Advances:''''' Hyperbaric oxygen therapy is already a cornerstone of modern medicine, and the application of mild hypoxia, that is, hypoxia conditioning (HC), to strengthen the resilience of organs or the whole body to severe hypoxic insults is an important preparation for high-altitude sojourns or to protect the cardiovascular system from hypoxic/ischemic damage. Many other applications of adaptations to hypo- and/or hyperoxia are only just emerging. HC-sometimes in combination with hyperoxic interventions-is gaining traction for the treatment of chronic diseases, including numerous neurological disorders, and for performance enhancement. '''''Critical Issues:''''' The dose- and intensity-dependent effects of varying oxygen concentrations render hypoxia- and/or hyperoxia-based interventions potentially highly beneficial, yet hazardous, although the risks versus benefits are as yet ill-defined. '''''Future Directions:''''' The field of low and high oxygen conditioning is expanding rapidly, and novel applications are increasingly recognized, for example, the modulation of aging processes, mood disorders, or metabolic diseases. To advance hypoxia/hyperoxia conditioning to clinical applications, more research on the effects of the intensity, duration, and frequency of altered oxygen concentrations, as well as on individual vulnerabilities to such interventions, is paramount.ities to such interventions, is paramount. +
'''12th Conference … '''12th Conference on Mitochondrial Physiology and MitoEAGLE WG and MC Meeting, 2017, Hradec Kralove, Czech Republic.'''Co-organized with COST Action MitoEAGLE: [[COST_Action_MitoEAGLE#Grant_periods |Management Committee Meeting and Working Group Meetings]].[[COST_Action_MitoEAGLE#Grant_periods |Management Committee Meeting and Working Group Meetings]]. +
'''13th Conference on Mitochondrial Physiology and MitoEAGLE WG and MC Meeting, 2018, Jurmala, Latvia.''' +
'''13th Workshop on High-Resolution Respirometry.''' Innsbruck, Tyrol, Austria; 1997 May 09-16. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''14thConference of the Asian Society of Mitochondrial Research and Medicine'''. Xi'an, Shaanxi, China; 2017 September. +
'''16th International Course on High-Resolution Respirometry.''' Innsbruck, Tyrol, Austria; 1998 December 10. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''19th European Bioenergetics Conference 2016, Riva del Garda, IT''' +
'''1st Workshop on Mitochondrial Functional Diagnostics - PBMCs.''' Innsbruck, Austria, 2023 +
'''2016 Jul 07-13, Kuehtai, AT.''' The pr … '''2016 Jul 07-13, Kuehtai, AT.''' The project [[K-Regio MitoFit |MitoFit]] aims at developing novel laboratory standards and diagnostic monitoring of a mitochondrial fitness score. With an international team of outstanding mitochondrial experts, the '''MitoFit Science Camp''' will provide a unique opportunity to receive first-hand introductions to state-of-the-art diagnostic monitoring of mitochondrial respiratory function combined with hands-on training on HRR (IOC112). Diverse areas are covered such as protective medicine, exercise physiology, mitochondrial pharmacology, aging, and comparative mitochondrial physiology (cell types, tissues, species). The common focus is on methodology, experimental details and quality control. The MitoFit Science Camp is a student- and research-oriented even, and may be considered as a sequence of workshops rather than a conference or school, addressing key topics of the COST Action [[MitoEAGLE]] project. This will provide a key opportunity to prepare the [[COST Action MitoEAGLE |1st Management Committee Meeting]].[[COST Action MitoEAGLE |1st Management Committee Meeting]]. +
'''2nd Padua-Mit-Innsbruck “Mitochondrial Conference”. Pauda, Italy; 2017 September. +
'''2nd Workshop on Mitochondrial Functional Diagnostics - Diagnostic database''' Innsbruck, Austria, 2023 +
'''2nd symposium Mitochondria in Health and Disease'''. New York, US; 2017. +
'''5th MiP''school'' on Mitochondrial Physiology, 2012 Jul 09-13, Cambridge, UK.''' +
'''64th Harden Conference on: Mitochondrial Physiology, 2007, Ambleside , United Kingdom.''' +
'''79th Harden Conference: Oxygen Evolution and Reduction - Common Principles, [https://www.biochemistry.org/Events/tabid/379/MeetingNo/79HDN/view/Conference/Default.aspx Harden Conference 2016], Innsbruck, AT''' +
'''>> [[MiP2013 Abstracts|MiP2013 Abstracts in the MiPMap]] - >> [[Laner 2013 Mitochondr Physiol Network MiP2013]]''' +
'''AIM/HYPOTHESIS''':Studies have suggeste … '''AIM/HYPOTHESIS''':Studies have suggested a link between insulin resistance and mitochondrial dysfunction in skeletal muscles. Our primary aim was to investigate the effect of aerobic training on mitochondrial respiration and mitochondrial reactive oxygen species (ROS) release in skeletal muscle of obese participants with and without type 2 diabetes.'''METHODS''': Type 2 diabetic men (''n'' = 13) and control (''n'' = 14) participants matched for age, BMI and physical activity completed 10 weeks of aerobic training. Pre- and post-training muscle biopsies were obtained before a euglycaemic-hyperinsulinaemic clamp and used for measurement of respiratory function and ROS release in isolated mitochondria.'''RESULTS''': Training significantly increased insulin sensitivity, maximal oxygen consumption and muscle mitochondrial respiration with no difference between groups. When expressed in relation to a marker of mitochondrial density (intrinsic mitochondrial respiration), training resulted in increased mitochondrial ADP-stimulated respiration (with NADH-generating substrates) and decreased respiration without ADP. Intrinsic mitochondrial respiration was not different between groups despite lower insulin sensitivity in type 2 diabetic participants. Mitochondrial ROS release tended to be higher in participants with type 2 diabetes.'''CONCLUSIONS/INTERPRETATION''': Aerobic training improves muscle respiration and intrinsic mitochondrial respiration in untrained obese participants with and without type 2 diabetes. These adaptations demonstrate an increased metabolic fitness, but do not seem to be directly related to training-induced changes in insulin sensitivity.ng-induced changes in insulin sensitivity. +
'''AIMS/HYPOTHESIS:''' We previously showe … '''AIMS/HYPOTHESIS:''' We previously showed that type 2 diabetic patients are characterised by compromised intrinsic mitochondrial function. Here, we examined if exercise training could increase intrinsic mitochondrial function in diabetic patients compared with control individuals.'''METHODS:''' Fifteen male type 2 diabetic patients and 14 male control individuals matched for age, BMI and VO(2max) enrolled in a 12 week exercise intervention programme. ''Ex vivo'' mitochondrial function was assessed by high-resolution respirometry in permeabilised muscle fibres from vastus lateralis muscle. Before and after training, insulin-stimulated glucose disposal was examined during a hyperinsulinaemic-euglycaemic clamp.'''RESULTS:''' Diabetic patients had intrinsically lower ADP-stimulated state 3 respiration and lower carbonyl cyanide 4-(trifluoro-methoxy)phenylhydrazone (FCCP)-induced maximal oxidative respiration, both on glutamate and on glutamate and succinate, and in the presence of palmitoyl-carnitine (''p'' < 0.05). After training, diabetic patients and control individuals showed increased state 3 respiration on the previously mentioned substrates (''p'' < 0.05); however, an increase in FCCP-induced maximal oxidative respiration was observed only in diabetic patients (''p'' < 0.05). The increase in mitochondrial respiration was accompanied by a 30% increase in mitochondrial content upon training (''p'' < 0.01). After adjustment for mitochondrial density, state 3 and FCCP-induced maximal oxidative respiration were similar between groups after training. Improvements in mitochondrial respiration were paralleled by improvements in insulin-stimulated glucose disposal in diabetic patients, with a tendency for this in control individuals.'''CONCLUSIONS/INTERPRETATION:''' We confirmed lower intrinsic mitochondrial function in diabetic patients compared with control individuals. Diabetic patients increased their mitochondrial content to the same extent as control individuals and had similar intrinsic mitochondrial function, which occurred parallel with improved insulin sensitivity.h occurred parallel with improved insulin sensitivity. +
'''APS Conference: Physiological Bioenergetics: Mitochondria from Bench to Bedside, Bioenergetics17'''. San Diego CA, USA; 2017 August. +
'''Abstract''': Add a short abstract here, … '''Abstract''': Add a short abstract here, including title, authors, affiliations, text (up to 250 words), and 2-6 references. You may edit your abstract any time. Information will be provided on a deadline for editing/submitting final abstracts (including a pdf file in final format), and on acceptance of the abstract for presentation at MiP2011.'''Title''': Not capitalized.'''Authors''': Presenting author with full name (first name spelled out), other authors with initials only. Numbers in parentheses after each author should indicate the affiliations.'''Addresses''': Numbers in parentheses are placed at the beginning of the address for indicating the affiliation. The e-mail address of the presenting author should be given at the end of all addresses.'''Main text''': Structured into paragraphs without headers. The standard structure of abstracts should be followed as appropriate (Introduction / Methods / Results / Conclusions / References). '''Figure''': You may submit one or two figures (jpg format), without caption if full explanation is given in the abstract.'''References''' in the text are given by numbers in brackets. Full references should be numbered and include all authors (family name and initials without punctuation), followed by the year of publication in parentheses, full title, journal name abbreviated with punctuation (italic), volume number followed by a colon, and first and last pages. See abstracts on the MiP website for style – MiP2005/Organisation/Abstracts. Tick on appropriate boxes blow in the list of 'Labels', and add additional keywords not covered in these labels.An extension is possible in the free text (not more than 2 pages). Further comments may be added in the discussion.r comments may be added in the discussion. +
'''Abstract''': Add a short abstract here, … '''Abstract''': Add a short abstract here, including title, authors, affiliations, text (up to 250 words), and 2-6 references. You may edit your abstract any time. Information will be provided on a deadline for editing/submitting final abstracts (including a pdf file in final format).'''Title''': Not capitalized.'''Authors''': Presenting author with full name (first name spelled out), other authors with initials only. Numbers in parentheses after each author should indicate the affiliations.'''Addresses''': Numbers in parentheses are placed at the beginning of the address for indicating the affiliation. The e-mail address of the presenting author should be given at the end of all addresses.'''Main text''': Structured into paragraphs without headers. The standard structure of abstracts should be followed as appropriate (Introduction / Methods / Results / Conclusions / References). '''Figure''': You may submit one or two figures (jpg format), without caption if full explanation is given in the abstract.'''References''' in the text are given by numbers in brackets. Full references should be numbered and include all authors (family name and initials without punctuation), followed by the year of publication in parentheses, full title, journal name abbreviated with punctuation (italic), volume number followed by a colon, and first and last pages. See abstracts on the MiP website for style – MiP2005/Organisation/Abstracts. Tick on appropriate boxes blow in the list of 'Labels', and add additional keywords not covered in these labels.An extension is possible in the free text (not more than 2 pages). Further comments may be added in the discussion.r comments may be added in the discussion. +
'''Abstracts are listed here in the frame of the [[MiPMap]] for the 7th MiP''school'' on Mitochondrial Physiology, 2015 Mar 24-28, Cape Town, ZA.''' +
'''Aim''' To examine if the body mass inde … '''Aim'''To examine if the body mass index (BMI) in midlife is related to cognitive function 30 years later in a dementia-free sample.'''Methods'''BMI was reported in 1963 at age 50–60 years, and cognitive abilities were examined 30 years later in a longitudinal design with 5 measurement occasions at 2-year intervals (n = 417). The cognitive abilities examined included tests of long-term memory, short-term memory, speed, verbal and spatial ability.'''Results'''Multilevel modeling adjusting for demographic and lifestyle factors, and relevant diseases showed that a higher BMI in midlife predicted lower test performance 30 years later. Significant associations between BMI and level of performance were found in all cognitive abilities; however, a higher midlife BMI was not associated with steeper cognitive decline.'''Conclusion'''Our results indicate that midlife overweight is related to lower overall cognitive function in old age. The fact that BMI-related effects were noted in mean-level cognitive performance, whereas only one ability showed differences in slopes, suggests that the negative effect of overweight has an onset before the entry into very old age. onset before the entry into very old age. +
'''Aim''': Skeletal muscle insulin resista … '''Aim''': Skeletal muscle insulin resistance has been linked to mitochondrial dysfunction. We examined how improvements in muscular insulin sensitivity following rosiglitazone (ROSI) or pioglitazone (PIO) treatment would affect muscle mitochondrial function in patients with type 2 diabetes mellitus (T2DM).'''Methods''': Muscle biopsies were obtained from 21 patients with T2DM before and after 12 weeks on either ROSI (4 mg once daily) [n = 12; age, 59.2 +/- 2.2 years; body mass index (BMI), 29.6 +/- 0.7 kg/m(2)] or PIO (30 mg once daily) (n = 9; age, 56.3 +/- 2.4 years; BMI, 29.5 +/- 1.5 kg/m(2)). An age- and BMI-matched control group was also included (n = 8; age, 61.8 +/- 2.3 years; BMI, 28.4 +/- 0.6 kg/m(2)). Insulin sensitivity, citrate synthase- and beta-hydroxyacyl-CoA-dehydrogenase (HAD) activity, intramuscular triglyceride (IMTG) and protein content of complexes I-IV were measured, while mitochondrial respiration per milligram muscle was measured in saponin-treated skinned muscle fibres using high-resolution respirometry.'''Results''': Mitochondrial respiration per milligram muscle was lower in T2DM compared to controls at baseline and decreased during ROSI treatment but increased during PIO treatment. Citrate synthase activity and average protein content of complexes I-IV were unchanged in the ROSI group, but protein content of complexes II and III increased during PIO treatment. Insulin sensitivity improved in all patients, but IMTG levels were unchanged.'''Conclusions''': We show opposite effects of ROSI and PIO on mitochondrial respiration, and also show that insulin sensitivity can be improved independently of changes in mitochondrial respiration. We confirm that mitochondrial respiration is reduced in T2DM compared to age- and BMI-matched control subjects. to age- and BMI-matched control subjects. +
'''Aim''': The subsarcolemmal (SSM) and in … '''Aim''': The subsarcolemmal (SSM) and interfibrillar (IFM) mitochondria in skeletal muscle appear to have distinct biochemical properties affecting metabolism in health and disease. The isolation of mitochondrial subpopulations has been a long-time challenge while the presence of a continuous mitochondrial reticulum challenges the view of distinctive SSM and IFM bioenergetics. Here, a comprehensive approach is developed to identify the best conditions to separate mitochondrial fractions.'''Methods''': The main modifications to the protocol to isolate SSM and IFM from rat skeletal muscle were: (a) decreased dispase content and homogenization speed; (b) trypsin treatment of SSM fractions; (c) recentrifugation of mitochondrial fractions at low speed to remove subcellular components. To identify the conditions preserving mitochondrial function, integrity, and maximizing their recovery, microscopy (light and electron) were used to monitor effectiveness and efficiency in separating mitochondrial subpopulations while respiratory and enzyme activities were employed to evaluate function, recovery, and integrity.'''Results''': With the modifications described, the total mitochondrial yield increased with a recovery of 80% of mitochondria contained in the original skeletal muscle sample. The difference between SSM and IFM oxidative capacity (10%) with complex-I substrate was significant only with a saturated ADP concentration. The inner and outer membrane damage for both subpopulations was <1% and 8%, respectively, while the respiratory control ratio was 16.'''Conclusion''': Using a multidisciplinary approach, conditions were identified to maximize SSM and IFM recovery while preserving mitochondrial integrity, biochemistry, and morphology. High quality and recovery of mitochondrial subpopulations allow to study the relationship between these organelles and disease.ionship between these organelles and disease. +
'''Aim:''' To investigate mechanisms behin … '''Aim:''' To investigate mechanisms behind heptanol (Hp)-induced infarct size reduction and in particular if protection by pre-treatment with Hp is triggered through mitochondrial mechanisms.'''Methods:''' Langendorff perfused rat hearts, isolated mitochondria and isolated myocytes were used. Infarct size, mitochondrial respiration, time to mitochondrial permeability transition pore (MPTP) opening and AKT and glycogen synthase kinase 3 beta (GSK-3β) phosphorylation were examined.'''Results:''' Pre-treatment with Hp reduced infarct size from 29.7 ± 3.4% to 12.6 ± 2.1%. Mitochondrial potassium channel blockers 5-hydroxy decanoic acid (5HD) blocking mitoK(ATP) and paxilline (PAX) blocking mitoK(Ca) abolished cardioprotective effect of Hp (Hp + 5HD 36.7 ± 2.9% and Hp + PAX 40.2 ± 2.8%). Hp significantly reduced respiratory control ratio in both subsarcolemmal and interfibrillar mitochondria in a dose-dependent manner (0.5-5.0 mm). The ADP oxygen ratio was also significantly reduced by Hp (2 mm). Laser scanning confocal microscopy of tetramethylrhodamine-loaded isolated rat myocytes using line scan mode showed that Hp increased time to MPTP opening. Western blot analysis showed that pre-treatment with Hp increased phosphorylation of AKT and GSK-3β before ischaemia and after 30 min of global ischaemia.'''Conclusion''': Pre-treatment with Hp protects the heart against ischaemia-reperfusion injury. This protection is most likely mediated via mitochondrial mechanisms which initiate a signalling cascade that converges on inhibition of opening of MPTP.onverges on inhibition of opening of MPTP. +
'''Aims/Hypothesis''': Mitochondrial respi … '''Aims/Hypothesis''': Mitochondrial respiration has been linked to insulin resistance. We studied mitochondrial respiratory capacity and substrate sensitivity in patients with type 2 diabetes (patients), and obese and lean control participants.'''Methods''': Mitochondrial respiration was measured in permeabilised muscle fibres by respirometry. Protocols for respirometry included titration of substrates for [[Complex I]] (glutamate), [[Complex II]] (succinate) and both (octanoyl-carnitine). Myosin heavy chain (MHC) composition, antioxidant capacity (manganese superoxide dismutase [MnSOD]), [[citrate synthase]] activity and maximal oxygen uptake (VO2) were also determined. Insulin sensitivity was determined with the isoglycaemic-hyperinsulinaemic clamp technique.'''Results''': Insulin sensitivity was different (''P'' < 0.05) between the groups (patients<obese controls<lean controls). MnSOD was lower in patients than in lean controls. MHC I content was lowest in patients (37 ± 11% [mean ± SE] vs 53 ± 6% and 56 ± 4%) vs obese controls and lean controls, respectively. VO2 was highest in lean controls (40 ± 3 ml min(-1) kg(-1) [mean ± SE]) compared with patients (25 ± 2) and obese controls (27 ± 2). Mitochondrial content (citrate synthase) was higher (''P'' < 0.05) in lean controls than in patients and obese controls. When normalised for mitochondrial content by citrate synthase, mitochondrial respiratory capacity was similar in all groups. However, the half maximal substrate concentration (''C''50) for Complex I was significantly lower (''P'' = 0.03) in patients (1.1 ± 0.2 mmol/l [mean ± SE]) than in obese (2.0 ± 0.3) and lean (1.8 ± 0.3) controls. Likewise, ''C''50 for Complex II was lower (''P'' = 0.02) in patients (3.5 ± 0.2 mmol/l [mean ± SE]) than in obese controls (4.1 ± 0.2), but did not differ from that in lean controls (3.8 ± 0.4). Substrate sensitivity for octanoyl-carnitine did not differ between groups.'''Conclusions/interpretation''': Increased mitochondrial substrate sensitivity is seen in skeletal muscle from type 2 diabetic patients and is confined to non-lipid substrates. Respiratory capacity per mitochondrion is not decreasedwith insulin resistance.spiratory capacity per mitochondrion is not decreased with insulin resistance. +
'''Authors:''' [[Othonicar Murilo F]] … '''Authors:''' [[Othonicar Murilo F]], [[Garcia Geovana S]], [[Oliveira Marcos Tulio]] Oxidative phosphorylation (OXPHOS) dysfunction can lead to decreased ATP levels and excessive reactive oxygen species (ROS) formation. Alternative enzymes (AEs) have been successfully used in model organisms to bypass OXPHOS defects and prevent high ROS levels, despite vertebrates and insects having lost their coding genes throughout evolution [1,2,3]. To get a deeper insight into the possible differences between AE-bearing and -lacking animals, we compared the genes coding for subunits of the OXPHOS complexes in tunicates of the genus ''Ciona'' with orthologs in ''Drosophila'' and humans. We found that ''Ciona'' species lack subunits necessary for the formation of respiratory supercomplexes (SCs), which are supramolecular organizations of the invidual OXPHOS complexes able to streamline electron transfer and prevent excessive ROS formation[4]. This suggests that ''Ciona'' species do not form SCs, or do so differently. In agreement, we also found that the ''Ciona intestinalis'' AE alternative oxidase (AOX), when transgenically expressed in ''Drosophila melanogaster'', preferentially receives electrons from the mitochondrial glycerol-3-phosphate dehydrogenase, which is not known to be involved in SCs. Only when ''Drosophila'' SCs appear to be disrupted, AOX is able to receive all electrons from Complex I, a well known SC component. We are currently investigating SC formation in AOX-expressing flies and in ''C. intestinalis''. Our findings could offer valuable insights for optimizing AOX expression in possible future therapeutic settings, and shed light on the evolutionary and functional variations between animal OXPHOS systems. # Szibor M, Schenkl C, Barsottini MR, Young L, Moore AL (2022) Targeting the alternative oxidase (AOX) for human health and food security, a pharmaceutical and agrochemical target or a rescue mechanism?. Biochemical Journal, 479(12), 1337-1359. https://doi.org/10.1042/BCJ20180192 # Viscomi C, Moore AL, Zeviani M, Szibor M (2023) Xenotopic expression of alternative oxidase (AOX) to study mechanisms of mitochondrial disease. Biochimica et Biophysica Acta (BBA)-Bioenergetics, 1864(2), 148947. https://doi.org/10.1016/j.bbabio.2022.148947 # Saari S. et al. (2019) Alternative respiratory chain enzymes: Therapeutic potential and possible pitfalls. Biochimica et Biophysica Acta (BBA)-Molecular Basis of Disease, 1865(4), 854-866.. https://doi.org/10.1016/j.bbadis.2018.10.012# Baker N, Patel J, Khacho M (2019) Linking mitochondrial dynamics, cristae remodeling and supercomplex formation: How mitochondrial structure can regulate bioenergetics. Mitochondrion, 49, 259-268. https://doi.org/10.1016/j.mito.2019.06.003 49, 259-268. https://doi.org/10.1016/j.mito.2019.06.003 +
'''Authors:''' Buescher F-M, [[Schrage-Knoll Irmtrud]] … '''Authors:''' Buescher F-M, [[Schrage-Knoll Irmtrud]], [[Bohmeier Maria]], Kaiser-Stolz C, Kramme J, Rittweger J, [[Pesta Dominik]] '''Introduction:''' Skeletal muscle mitochondrial function is altered in insulin resistant states. Its assessment, however, requires invasive muscle biopsies to obtain viable tissue for functional mitochondrial analysis. Blood cell-based bioenergetics potentially reflects systemic mitochondrial function. Here, we characterized respiratory capacity of skeletal muscle mitochondria and peripheral blood mononuclear cells (PBMCs) from patients with type 2 diabetes and assessed whether the latter reflect muscle mitochondrial respirometric measures. '''Methods:''' For that purpose, 20 patients with type 2 diabetes (30 % female, 57±9 years, BMI 28±4 kg/m2) participated in this study. We obtained muscle biopsies from the M. vastus lateralis and venous blood samples to isolate PBMCs. High-resolution respirometry was performed in duplicate to assess mitochondrial respiration from permeabilized muscle fibers and PBMCs using an established SUIT-protocol. '''Results and Discussion:''' Combined NADH-linked (N) electron transfer and succinate-linked (S) OXPHOS capacity was 59.4±13.0 pmol/(s*mg) for muscle and 16.6±5.3 pmol/(s*106 cells) for PBMCs. NS-OXPHOS capacity was not different between females and males for muscle (66.5±9.5 vs 56.3±13.0 pmol/(s*mg), p=0.10) or PBMCs (19.5±5.3 vs 15.3±5.0 pmol/(s*106), p=0.10), respectively. While PBMC mitochondrial function was not correlated with skeletal muscle respiratory function across several respiratory states (all p>0.05), muscle NS-OXPHOS capacity correlated negatively with diabetes disease duration (r=-0.50, p=0.02). These results suggest that there are no sex-specific differences with regard to muscle and PBMC mitochondrial function in individuals with type 2 diabetes. While bioenergetic phenotypes in PBMCs do not reflect muscle mitochondrial function in this cohort, diabetes disease duration negatively associates with muscle mitochondrial function. hort, diabetes disease duration negatively associates with muscle mitochondrial function. +
'''Authors:''' [[Alan Lukas]] … '''Authors:''' [[Alan Lukas]], [[Calvo E]], [[Enriquez Jose A]], [[Soriano ME]], [[Bean C]], [[Mracek Tomas]] and [[Scorrano Luca]] '''Introduction:''' Obesity is turning into a worldwide pandemic, with most patients also affected by other comorbidities such as type 2 diabetes, hypertension, or cardiovascular disease. With mitochondria being a major site for fatty acid oxidation, they represent an important target for obesity treatment. Mitochondria are dynamic organelles, and their morphology influences both the organization of membrane protein complexes as well as mitochondrial substrate preference1. '''Methods:''' By combining 2-dimension blue native gel electrophoresis with proteomics and bioinformatics in heart mitochondria undergoing membrane remodelling we identified a strong correlation between the key cristae biogenesis protein Opa1 and Vwa8, a putative AAA+ ATPase with a dynein conformation. In order to study the role of Vwa8 protein in mitochondrial physiology, we developed the HEK293 Vwa8 knock-out cell line and Vwa8 KO mice. '''Results and discussion:''' Vwa8 protein localized to the mitochondrial intermembrane space where it formed discrete spots. Deletion of Vwa8 led to an increase in mitochondrial respiration on fatty acids but not on glucose or glutamine. The Vwa8 KO mice showed decreased resting energy requirements as well as higher heat production, indicating a stronger preference for lipid oxidation. Moreover, the subcutaneous adipose tissue of Vwa8 KO mice showed increased markers of browning such as an increase in mitochondria content and lipid droplet multilocularity. The Vwa8 KO mice remained more insulin sensitive and with higher lean mass proportion upon a high-fat diet. In conclusion, Vwa8 affects mitochondrial substrate preference, induces browning of subcutaneous adipose tissue and represents a new target for obesity treatment. # Alan L, Scorrano L. (2022) Shaping fuel utilization by mitochondria. Curr Biol. 2022 Jun 20;32(12):R618-R623. doi: 10.1016/j.cub.2022.05.006.r Biol. 2022 Jun 20;32(12):R618-R623. doi: 10.1016/j.cub.2022.05.006. +
'''Authors:''' [[Arabie D]] … '''Authors:''' [[Arabie D]], [[Hand Steven C]] '''Introduction:''' Invertebrate extremophiles experience metabolic transitions promoted by diapause, anoxia and extreme dehydration/rehydration [1-3]. For embryos of brine shrimp, ''Artemia franciscana'', these reversible shifts are dramatic with respiration depressed below 1% of active states. Recovery from metabolic disruption in mammals is accompanied by generation of reactive oxygen species (ROS) that cause tissue damage during ischemia-reperfusion [4]. Yet embryos of ''A. franciscana'' survive frequent shifts in metabolism, which implies their mitochondria are poised to tolerate such reactivations without accumulation of damaging ROS. '''Methods:''' Mitochondria were isolated [5] and subjected to anoxia for 30 min while controls received continuous normoxia [4]. Samples were pelleted and resuspended in oxygenated buffer containing fresh substrate, ADP and Amplex Red assay components [4]. Parallel samples included auranofin and dinitrochlorobenzene (DNCB) to inhibit thioredoxin reductase and glutathione peroxidase, respectively. Protein carbonyls, aconitase/citrate synthase activity ratios, and lipid hydroperoxides were quantified [4,6]. '''Results and Discussion:''' H2O2 accumulation did not increase significantly in mitochondria exposed to anoxia-reoxygenation compared to normoxic controls. By comparison, an 8-fold increase in H2O2 was reported for rat heart mitochondria given the same treatment [4]. As anticipated, inclusion of auranofin and DNCB statistically increased the H2O2 accumulation 2-3 fold in both control and experimental mitochondria. Consistent with the lack of elevated H2O2 after anoxia-reoxygenation, aconitase inactivation also was not detected compared to controls. Statistical increases were not observed in protein carbonyls or lipid hydroperoxides. Evidence suggests mitochondria from ''A. franciscana'' embryos are well protected against ROS accumulation and oxidative damage during severe metabolic transitions. # Hand SC, Denlinger DL, Podrabsky JE, Roy R (2016) Mechanisms of animal diapause: Recent developments from nematodes, crustaceans, insects and fish. https://doi.org/10.1152/ajpregu.00250.2015# Hand SC, Menze MA, Borcar A, Patil Y, Covi JA, Reynolds JA, Toner M (2011) Metabolic restructuring during energy-limited states: Insights from ''Artemia franciscana'' embryos and other animals. https://doi.org/10.1016/j.jinsphys.2011.02.010# Hand SC, Moore DS, Patil Y (2018) Challenges during diapause and anhydrobiosis: mitochondrial bioenergetics and desiccation tolerance. https://doi.org/10.1002/iub.1953# Chouchani et al. (2013) Cardioprotection by S-nitrosation of a cysteine switch on mitochondrial Complex I. https://doi.org/10.1038/nm.3212# Kwast K, Hand SC (1993) Regulatory features of protein synthesis in isolated mitochondria from ''Artemia'' embryos. https://doi.org/10.1152/ajpregu.1993.265.6.R1238# Chouchani et al. (2016) Mitochondrial ROS regulate thermogenic energy expenditure and sulfenylation of UCP1. https://doi.org/10.1038/nature17399== Affiliation and acknowledgements ==::::Arabie D, Hand Steven C:::: Dept Biological Sciences, Louisiana State Univ, Baton Rouge, USA:::: Corresponding author: shand@lsu.edu.:::: '''Funding:''' NSF grant IOS-1457061/IOS-1456809Hand Steven C :::: Dept Biological Sciences, Louisiana State Univ, Baton Rouge, USA :::: Corresponding author: shand@lsu.edu. :::: '''Funding:''' NSF grant IOS-1457061/IOS-1456809 +
'''Authors:''' [[Axelrod Christopher L]] … '''Authors:''' [[Axelrod Christopher L]], [[Kirwan John P]] Obesity mediates the onset of lipid-induced insulin resistance, increasing the risk of type 2 diabetes. The inability of mitochondria to maintain core functions such as ATP synthesis, redox homeostasis, organelle quality control, and/or preservation of inheritance is proposed to link obesity-related insulin resistance to the onset and progression of type 2 diabetes, yet evidence remains elusive. To parse out the contributions of obesity versus peripheral insulin resistance, healthy weight adults were infused with an intralipid solution followed by evaluation of skeletal muscle mitochondrial function. The lipid infusion reduced insulin sensitivity and dampened mitochondrial membrane potential while increasing markers of mitochondrial fission and increasing the presence of autophagic vesicles, consistent with activation of the quality control machinery. Despite this, respiratory capacity and mitochondrial content were unaltered. From these studies, we concluded that activation of mitochondrial fission and quality control were early events in the onset of insulin resistance to defend cellular energy homeostasis. Subsequently, we conducted a cross-sectional analysis of individuals across the insulin sensitivity spectrum. We observed that markers of fission and quality control were markedly altered in patients with obesity and type 2 diabetes relative to obesity alone and healthy weight despite no apparent differences in respiratory capacity. Mitochondrial volume was incrementally lower in patients with obesity and type 2 diabetes relative to healthy weight. Collectively, we conclude that preservation of bioenergetic function in patients with obesity and type 2 diabetes is achieved by chronic activation of the quality control machinery which occurs at the expense of mitochondrial volume.y which occurs at the expense of mitochondrial volume. +
'''Authors:''' [[Barkova Daria]] … '''Authors:''' [[Barkova Daria]], [[Ukropec Jozef]], [[Nemec Michal]], [[Slobodova L]], [[Schoen M]], [[Tirpakova V]], [[Krumpolec P]], [[Sumbalova Zuzana]], [[Vician M]], [[Sedliak M]], [[Ukropcova Barbara]] '''Introduction:''' Regular exercise supports healthy ageing and reduces risk of elderly chronic diseases. Respirometry is an important tool in understanding the physiological adaptations in response to physical activity at cellular level. Previously, we showed that 3-month exercise training increases muscle metabolism in the elderly. Present study is aimed to assess the effects of long-term training on muscle oxidative capacity in the subset of individuals continuing regular training for 5 years. '''Methods:''' Volunteers (n=60, 66.9±1.2 years, 27.1±3.9 kg/m2) were recruited for 3-month intervention study: 36 of them underwent aerobic-strength training, 24 volunteers were active controls. A volunteer subpopulation continued aerobic-strength training for next 5 years (n=15), and is compared to non-exercising controls (n=15). Body composition, glucose tolerance, insulin sensitivity and other metabolic parameters were assessed. Samples of m. vastus lateralis obtained by biopsy were used for measurement of muscle mitochondria oxygen consumption by O2k high-resolution respirometry, applying RP1 SUIT protocol. '''Results and discussion:''' Three-month exercise training enhanced muscle mitochondrial respiration rate in the elderly undergoing exercise training compared to controls. So far, two individuals completed follow up phenotyping after 5 years training. A slight deterioration in anthropometric (increased BMI by ~ 8 % and visceral fat content by ~ 36%) and metabolic parameters was observed, together with a reduction in muscle mitochondrial respiration (by ~ 15 %). Short-term training improved the whole-body and muscle metabolism in the elderly. Obtaining data from exercising and non-exercising cohorts (currently ongoing) will allow us to assess the impact of a long-term intervention.ongoing) will allow us to assess the impact of a long-term intervention. +
'''Authors:''' [[Brunetta Henver Simionato]] … '''Authors:''' [[Brunetta Henver Simionato]], [[Palermo Ruiz Gabriel]], [[Ludwig Raissa]], [[Ruberti Olivia]], [[Bechara Luiz]], [[Consonni Silvio]], [[Rodrigues Bruno]], [[Ferreira Julio Cesar B]], [[Mori Marcelo AS]] The negative effects of high-fat high-sucrose (HFHS) diet consumption on heart function are exacerbated in mice lacking DICER in adipocytes (AdicerKO). These findings suggest a protective role of adipocyte-derived microRNAs on heart physiology. Exercise training is known to have a protective role in cardiometabolic diseases. However, it is not known whether chronic aerobic training is able to rescue heart dysfunction in HFHS-fed AdicerKO mice. Here, we fed AdicerKO mice with a HFHS diet for 12 weeks, after confirming the deleterious effects of the diet on these mice, we submitted them to moderate aerobic training for 8 weeks, 5 days/week for 60 minutes each section while keeping them on HFHS-diet. Chronic aerobic training restored end-systolic volume and stroke volume in the hearts of HFHS-fed AdicerKO mice without changing ejection fraction. In addition, aerobic exercise increased left ventricle diameter in both, systolic and diastolic, phases. Notably, HFHS-fed AdicerKO-trained mice presented lower heart rate with no differences in systolic blood pressure compared to HFHS-fed AdicerKO sedentary mice. Mechanistically, chronic exercise training lowered mitochondrial H2O2 emission and oxidative stress alongside greater lipid- and succinate-supported mitochondrial respiration. Importantly, these effects were not followed by changes in triacylglycerol content within the left ventricle or fibrosis. In summary, chronic aerobic training is capable to rescue heart function of HFHS-fed AdicerKO mice in association with improvements in mitochondrial bioenergetics and redox balance.ssociation with improvements in mitochondrial bioenergetics and redox balance. +
'''Authors:''' [[Cardoso Luiza HD]] … '''Authors:''' [[Cardoso Luiza HD]], [[Donnelly Chris]], [[Komlodi Timea]], [[Doerrier Carolina]], [[Gnaiger Erich]] '''Introduction:''' Multiple mt-matrix dehydrogenases reduce NAD+ to NADH+H+, which is oxidized by CI (N-junction). Convergent electron flow through several mt-Complexes (CI, CII, CETF, etc) reduces electron transfer system (ETS)-reactive ubiquinone (UQ) to ubiquinol (UQH2), which is oxidized by CIII (Q-junction). The aim of our study was to analyze the relationships between the N- and Q-redox states and electron transfer rates. '''Methods:''' Respiration and N- or Q-redox fractions were measured simultaneously with the Oroboros NextGen-O2k. Multiple protocols were used with sequential titrations of substrates, inhibitors, and uncouplers [1, 2]: N-pool with pyruvate&glutamate&malate, mouse liver mitochondria; Q-pool with succinate&rotenone, octanoylcarnitine&malate or palmitoylcarnitine&malate, permeabilized HEK 293T. After substrates, ADP, CCCP and antimycin A were titrated. '''Results and discussion:''' Varying energy supply upstream of the Q-junction by using combinations of substrates and ETS-inhibitors in the noncoupled state, the Q-pool became reduced in direct proportion to respiration. In contrast, varying downstream energy demand in the absence of ADP (LEAK), by ADP activation (OXPHOS), and by uncoupler titrations (ET capacity), the N- and Q-pools were reduced in indirect proportion to respiration. The opposite correlations between redox state and respiratory rate were explained by the contrasting effects of varying electron push from different fuel substrates of the ETS or electron pull modulated by coupling and corresponding energy demand. Special emphasis on the interaction between fatty acid oxidation, CI, and CII – all involving separate electron entries into the Q-junction [3] – is particularly relevant in the context of obesity and bioenergetics studies.# Komlódi T, Cardoso LHD, Doerrier C, Moore AL, Rich PR, Gnaiger E (2021) Coupling and pathway control of coenzyme Q redox state and respiration in isolated mitochondria. https://doi.org/10.26124/bec:2021-0003# Gnaiger E (2020) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 5th ed. https://doi.org/10.26124/bec:2020-0002 # Gnaiger E (2023) Complex II ambiguities ― FADH2 in the electron transfer system. https://doi.org/10.26124/mitofit:2023-0003.v4 E (2023) Complex II ambiguities ― FADH2 in the electron transfer system. https://doi.org/10.26124/mitofit:2023-0003.v4 +
'''Authors:''' [[Chicco Adam J]] … '''Authors:''' [[Chicco Adam J]], [[Le Catherine H]], [[Mulligan Christopher M]], [[Whitcomb Luke A]], [[Evans Amanda E]], [[Routh Melissa A]], [[Sparanga Genevieve C]] Cardiolipin (CL) is a tetra-acyl mitochondrial phospholipid that supports the optimal function of several mitochondrial membrane proteins and processes. In the healthy mammalian heart, the majority of CL species contain four linoleate acyl chains (L4CL). A marked depletion of cardiac L4CL is paralleled by an increase in CL species containing docosahexaenoic acid (DHA) in hyperphagic obese (''Lepob''; OB) mice despite no change in dietary fat composition [1], but the mechanisms and functional relevance of these changes are unclear. We hypothesized that this shift in CL composition results from increased activity of delta-6 desaturase (D6D), the rate limiting enzyme in the biosynthesis of DHA and conversion of linoleate into highly unsaturated ω-6 fatty acids, by altering the distribution of fatty acids available for CL remodeling. To test this, we administered the selective D6D inhibitor SC-26196 (100 mg/kg/d in chow) to 4-5 month-old OB or lean (C57Bl/6) mice for 4 weeks. As hypothesized, D6D inhibition reversed obesity-related changes in cardiac CL composition, restoring L4CL and DHA-enriched CL species to within 5 % of levels in lean mice, which paralleled reciprocal shifts in the linoleate and DHA levels of total myocardial phospholipids. Obesity-related decreases in cardiac mitochondrial respiratory control by ADP (with NS pathway substrates) and greater mitochondrial H2O2 release during both LEAK and OXPHOS states were also abolished by D6D inhibition. These results corroborate accumulating evidence that cardiac CL composition is strongly influenced by the membrane fatty acids available for CL remodeling [2-3], and may impact the bioenergetic efficiency of mitochondrial respiration. # Han X, Yang J, Yang K, ZhongdancZ, Abendschein DR, Gross RW (2007) Alterations in Myocardial Cardiolipin Content and Composition Occur at the Very Earliest Stages of Diabetes: A Shotgun Lipidomics Study Biochemistry https://doi.org/10.1021/bi7004015 # Le CH et al. (2014) Delta-6-desaturase links PUFA metabolism with phospholipid remodeling and disease progression in heart failure. https://doi.org/10.1161/CIRCHEARTFAILURE.113.000744 # Oemer G, Edenhofer ML, Wohlfarter Y, Lackner K, Leman G, Koch J, Cardoso LHD, Lindner HH, Gnaiger E, Dubrac S, Zschocke J, Keller MA (2021) Fatty acyl availability modulates cardiolipin composition and alters mitochondrial function in HeLa cells. https://doi.org/10.1016/j.jlr.2021.100111 and alters mitochondrial function in HeLa cells. https://doi.org/10.1016/j.jlr.2021.100111 +
'''Authors:''' [[Giordano Luca]] … '''Authors:''' [[Giordano Luca]], [[Nolte A]], [[Wittig Ilka]], [[Pak Oleg]], [[Knoepp F]], [[Ramser K]], [[Wahl J]], [[Cabrera A]], [[Huettemann Maik]], [[Grossman Lawrence]], [[Pecina Petr]], [[Ghofrani HA]], [[Seeger W]], [[Weissmann Norbert]], [[Giehl K]], [[Sommer Natascha]] '''Introduction:''' Hypoxia in the lung alveoli triggers the contraction of the small precapillary pulmonary arteries, i.e., hypoxic pulmonary vasoconstriction (HPV), avoiding life-threatening hypoxemia. Pulmonary arterial smooth muscle cells (PASMCs) are involved in HPV, with the mitochondrial cytochrome c oxidase (COX) subunit 4 isoform 2 (Cox4i2) playing an essential role in the acute oxygen sensing1. Nonetheless, the molecular mechanism by which Cox4i2 sensitizes the whole COX remains unclear. '''Methods:''' We analysed superoxide production by MitoSOX, oxygen consumption by high-resolution respirometry, redox changes of the electron transport system (ETS) by RAMAN spectroscopy, and supercomplex formation by blue native gel analysis of PASMCs isolated from wild type (WT) and Cox4i2 knockout mice (Cox4i2 KO) exposed to normoxia or hypoxia. To figure out the role of Cox4i2-specific cysteine residues we generated mouse epithelial (CMT167) cells overexpressing either Cox4i1, or WT Cox4i2, or Cox4i2 mutants (C41S, C55A, C109S), and we tested their superoxide production and oxygen affinity. '''Results:''' Respiration, abundance, and COX assembly were similar in WT and Cox4i2 KO PASMCs. On the contrary, hypoxia-induced production of superoxide and the reduction of ETS components (NADH, ubiquinol, cytochrome c) was prevented in Cox4i2 KO PASMCs. CMT167 cells expressing either Cox4i1, or Cox4i2 mutants lacked hypoxia-induced superoxide production, which was detected only in cells expressing WT Cox4i2. Overexpression of Cox4i1, or Cox4i2, or Cox4i2 mutants did not affect oxygen affinity. Our findings suggests that Cox4i2 does not alter superoxide production by rearrangement of supercomplexes, but by the reduction of the ETS, likely mediated by the cysteine residues.Sommer N, Hüttemann M, et al. Mitochondrial Complex IV Subunit 4 Isoform 2 Is Essential for Acute Pulmonary Oxygen Sensing. Circ Res. 2017;121(4):424-38.r Acute Pulmonary Oxygen Sensing. Circ Res. 2017;121(4):424-38. +
'''Authors:''' [[Guerrier Lisa]] … '''Authors:''' [[Guerrier Lisa]], [[Malpuech-Brugere C]], [[Bacoeur-Ouzillou O]], [[Cassagnes L]], [[Pezet D]], [[Gagniere J]], [[Richard R]], [[Touron Julianne]] '''Introduction:''' Adipose tissue (AT), as an endocrine organ, plays an important role in health and diseases, but unlike skeletal muscle, its energy metabolism have been under investigated due to technical limitations. Nevertheless, according to recent studies, mitochondria could play a predominant role in AT disorders and their activity could depend on adiposity level (1-3). This study aims to evaluate mitochondrial activity and metabolism of human visceral and subcutaneous white AT and their relationship with body mass index (BMI) and composition. '''Methods:''' Sixty-two patients undergoing digestive surgery, without chemotherapy, nor parietal infection, have been included in the study with BMI ranging from 15.4 to 51.9 kg·m-2. Their body composition was assessed by computed tomographic (CT) image at third lumbar vertebra (L3). Mitochondrial function was measured in situ in digitonin-permeabilized adipocytes using high resolution respirometry and a substrate/inhibitor titration approach (Figure) (4,5). Protein accumulation of mitochondrial and lipid metabolism key elements was evaluated by Western-blot. '''Results and discussion:''' Results showed a negative correlation between maximal mitochondrial respiration and BMI (p<0.05) as well as with AT surface, regardless of the anatomical location, though, OXPHOS respiration was significantly higher in visceral (2.22±0.15 pmol·sec-1·mg-1) than in the subcutaneous AT (1.79±0.17 pmol·sec-1·mg-1). Thus, mitochondrial function can be studied with small amount of AT despite its low mitochondrial density and can be discriminated according to AT depot and BMI. Further analyses are required to know whether the observed differences are quantitative and/or qualitative, as well as to identify the mechanisms involved # Ling Y et al. (2019) Persistent low body weight in humans is associated with higher mitochondrial activity in white adipose tissue. https://doi.org/10.1093/ajcn/nqz144# Fischer B, Schöttl T, Schempp C, Fromme T, Hauner H, Klingenspor M, Skurk T (2015) Inverse relationship between body mass index and mitochondrial oxidative phosphorylation capacity in human subcutaneous adipocytes. https://doi.org/10.1152/ajpendo.00524.2014# Wessels B, Honecker J, Schöttl T, Stecher L, Klingenspor M, Hauner H, Skurk T (2019) Adipose Mitochondrial Respiratory Capacity in Obesity is Impaired Independently of Glycemic Status of Tissue Donors. https://doi.org/10.1002/oby.22435# Kraunsøe R, Boushel R, Neigaard Hansen C, Schjerling P, Qvortrup K, Støckel M, Mikines KJ, Dela F (2010) Mitochondrial respiration in subcutaneous and visceral adipose tissue from patients with morbid obesity. https://doi.org/10.1113/jphysiol.2009.184754# Sahl RE, Frederikke Høy Helms E, Schmücker M, Flensted-Jensen M, Ingersen A, Morville T, Dela F, Wulff Helge J, Larsen S (2021) Reliability and variation in mitochondrial respiration in human adipose tissue. https://doi.org/10.1080/21623945.2021.1991617en S (2021) Reliability and variation in mitochondrial respiration in human adipose tissue. https://doi.org/10.1080/21623945.2021.1991617 +
'''Authors:''' [[Holloway Graham P]] … '''Authors:''' [[Holloway Graham P]], [[Petrick Heather L]], [[van Loon LJC]] Mitochondria play a key role in metabolic homeostasis, with impaired mitochondrial biology directly linked with numerous pathological conditions, including skeletal muscle atrophy, insulin resistance and heart dysfunction. Our team has focused on identifying nutritional approaches that preserve mitochondrial bioenergetics as a preventative medicine approach. In particular, we have studied dietary nitrate, which can be consumed through foods such as beets and green leafy vegetables or supplementation, as this compound appears to positively affect mitochondrial bioenergetics in diverse tissues. Additionally, we have shown that dietary nitrate can prevent high-fat diet-induced cardiac dysfunction, whole-body insulin resistance, dyslipidemia, and hepatic dysfunction. Moreover, we have recently uncovered that nitrate prevents skeletal muscle disuse-mediated reductions in mitochondrial protein synthesis rates (FSR), mitochondrial protein content, respiration and prevented the normal increase mitochondrial reactive oxygen species (ROS) emission during limb immobilization. While these physiological outcomes are likely in part linked to the serial reduction of nitrate to systemic nitric oxide (NO)-mediated vasodilation, we have also utilized fecal microbial transplantation from nitrate-fed donors to prevent HFD-induced cardiac dysfunction in the absence of increasing serum nitrate or reducing blood pressure. Given these systemic, reproducible, and consistent effects, nitrate appears to represent a viable therapeutic approach to improve mitochondrial bioenergetics to combat compromised cardiometabolic health in diverse situations.promised cardiometabolic health in diverse situations. +
'''Authors:''' [[Jasinska Joanna]] … '''Authors:''' [[Jasinska Joanna]], [[Bednarczyk Piotr]], [[Kalenik B]], [[Kulawiak Bogusz]], [[Wrzosek A]], [[Szewczyk Adam]] Recent studies point out that mitochondria are not only a source of ATP in the cell, but more and more data indicate their role related to Ca2+ buffering, production of reactive oxygen species (ROS) and activation of intracellular signaling pathways of necrosis and apoptosis. Recent studies clearly indicate that mitochondrial potassium channels (mitoK) present in the inner mitochondrial membrane play an important protective role in the ischemia-reperfusion processes of myocardial cell damage. These results were obtained using low molecular weight chemicals. Due to the lack of selective modulators of potassium channels, we opted for an alternative approach to modulate the activity of mitoK channels by changing the redox state of the respiratory chain, which we have demonstrated in previous studies. Some respiratory chain proteins are thought to absorb infrared (IR) light. Cytochrome c oxidase (COX) may be important in these mechanisms because it has four metal redox centers: binuclear CuA, CuB, heme a, and heme a3. All these metal centers are able to absorb light waves in the IR region. Data obtained in our laboratory indicate that COX may be functionally linked to mitochondrial high-conductance Ca2+-activated potassium channels (mitoBKCa) in the U87 cell line1. Using the patch-clamp technique with the illumination system, we exposed the mitoBKCa channel. We observed that in the presence of ferricyanide, channel activity was inhibited and that mitoBK channel activity could be restored by 820 nm illumination, suggesting that COX is involved in the modulation of mitoBK channel activity.# Szewczyk A and Bednarczyk P (2018) Modulation of the Mitochondrial Potassium Channel Activity by Infrared Light. https://doi.org/10.1016/j.bpj.2017.11.288ed Light. https://doi.org/10.1016/j.bpj.2017.11.288 +
'''Authors:''' [[Karabatsiakis Alexander]] … '''Authors:''' [[Karabatsiakis Alexander]], [[Manrique Juan-Salinas]], [[Stoll Thomas]], [[Hennessy Thomas]], [[Hill Michelle M]], [[Dietrich Detlef E]] Major depressive disorder (MDD) is characterized by impairments in mental and physical performance. Despite intensified hypothesis-driven research, applicable biomarkers for MDD are missing. Research showed that MD is associated with impaired mitochondrial bioenergetic functioning in peripheral blood mononuclear cells (PBMC). However, deeper biomolecular insights into bioenergetic and associated biochemical changes in blood underlying the pathophysiology of MDD are necessary to identify new biomarker candidates. Here, the biochemistry of PBMC-surrounding blood was analyzed using a hypothesis-free biomarker identification approach combining metabolite and lipid fingerprinting. Biochemical fingerprints of serum were compared between female individuals (N = 44) with and without MDD. Serum extracts were separated by liquid chromatography and detected with time-of-flight mass spectrometry. The data was analyzed by multiple group comparisons and correlations, as well as two multivariate classification procedures. Next, our previously identified alterations in mitochondrial bioenergetics in PBMC were co-considered as an outcome for our biomarker identification approach. Consequently, the most promising compound was tested for correlation with mitochondrial respiration. Nine biomarker candidates discriminated between MDD and non-MDD with high predictive accuracy (90.9 %). The detected compounds are involved in lipid and amino acid-metabolism. ''9,10-dihydroxy-octadenedioic acid'' was revealed as a robust biomarker candidate with a predictive accuracy of 81.8 % and significant mean positive correlation with parameters of mitochondrial respiration (r = 0.31-0.48, p<0.01). Our fingerprinting results highlight novel biomarker candidates and associated pathways for MDD research. The unraveled biochemical pathways indicate a modulated association of MDD with inflammation, oxidative stress, and mitochondrial bioenergetics. The biomarker candidates have to be replicated in independent cohorts of all ages & sexes.be replicated in independent cohorts of all ages & sexes. +
'''Authors:''' [[Kopecky Jan]] … '''Authors:''' [[Kopecky Jan]], [[Zouhar Petr]], [[Janovska Petra]], [[Bardova K]], [[Otahal J]], [[Vrbacky Marek]], [[Mracek Tomas]], [[Adamcova K]], [[Lenkova L]], [[Funda J]], [[Cajka T]], [[Drahota Zdenek]], [[Stanic S]], [[Rustan Arild C]], [[Horakova Olga]], [[Houstek Josef]], [[Rosmeissl M]] Heat production is essential for maintaining a constant body temperature, and is an important component of energy balance. Well-described mechanisms involved in heat generation include shivering of muscle and non-shivering thermogenesis (NST) in brown adipose tissue (BAT). Thermogenesis in BAT, which is dependent on the presence of the mitochondrial protein UCP1, is the focus of interest for its potential use in the treatment of obesity. Other mechanisms of NST and their significance are relatively poorly understood. We have shown [1] that obesity-resistant A/J mice acclimated to cold failed to increase adrenergically stimulated NST in BAT and activated NST in skeletal muscle instead. Heat generation in muscle involved increased calcium ion cycling in the endoplasmic reticulum associated with higher mitochondrial oxidative activity. The involvement of different thermogenic mechanisms could be related to the different susceptibility to obesity. The resistance of A/J mice to obesity may result, at least in part, from their ability to activate NST in muscle. Such mechanism may provide a more promising way to treat obesity than potential therapies based on increasing thermogenesis in BAT, as the capacity of skeletal muscle of adult human to burn fat energy stores is several fold greater than in BAT. Thus, only a relatively small increase in thermogenesis in muscle could significantly reduce adipose tissue deposition. How to achieve such an increase is a challenge for further research. # Janovska P et al., 2023, Mol Metab. https://doi.org/10.1016/j.molmet.2023.101683Metab. https://doi.org/10.1016/j.molmet.2023.101683 +
'''Authors:''' [[Mahapatra Gargi]] … '''Authors:''' [[Mahapatra Gargi]], [[Gao Zhengrong]], [[Bateman James R III]], [[Lockhart Samuel Neal]], [[Bergstrom Jaclyn]], [[Craft Suzanne]], [[Molina Anthony JA]] Impaired glucose tolerance (IGT), including prediabetes and diabetes, increases risk of developing age related disorders, including Alzheimer’s disease (AD). We analyzed mitochondrial bioenergetics in platelets collected from 208 adults, 55 years and older, with or without insulin sensitivities (112 normoglycemics (NG), 96 IGTs). Platelets from IGT participants exhibited unique bioenergetic profiles exemplified by higher mitochondrial respiration than NG. IGT platelets exhibited higher glucose-dependent maximal (Max) and spare respiratory (SRC) capacities compared to NG, and higher fatty acid oxidation-dependent maximal coupled (MaxOXPHOS) and uncoupled (MaxETS) respiration compared to NG. Correlating bioenergetics from all 208 participants combined with glucose measures (OGTT_120, OGTT_AUC, and HbA1c) revealed significant positive associations. Most associations were unaltered with age, sex, and BMI adjustments. Further separating NG and IGT participants and correlating platelet respiration with glucose measures revealed distinct trends in NG versus IGT group. In NG, previously observed associations remained intact, and new significant positive associations emerged between platelet bioenergetics and HbA1c. Associations in IGT group were overall negative. Identifying systemic mitochondrial mechanisms that associate with glucose intolerance in older adults will help in monitoring pathological progression of AD in relation to comorbidities such as insulin sensitivity, and supports the development of minimally invasive biomarkers of AD.# Mahapatra G, Gao, Bateman JR III, Lockhart SN, Bergstrom J, DeWitt AR, Piloso JE, Kramer PA, Gonzalez-Armenta JL, Amick A, Casanova R, Craft S, Molina AJA (2022) Blood-Based Bioenergetic Profiling Reveals Differences in Mitochondrial Function Associated with Cognitive Performance and Alzheimer’s Disease Alzheimer's & Dementia 2022. https://doi.org/10.1002/alz.12731 & Dementia 2022. https://doi.org/10.1002/alz.12731 +
'''Authors:''' [[Nagwani Amit K]] … '''Authors:''' [[Nagwani Amit K]], [[Kaczmarek L]], [[Kmita H]] '''Introduction:''' Tardigrades are considered as one of the toughest animals on Earth due to their remarkable ability to withstand extreme condition. An example of these conditions is hypomagnetic field (HMF, static magnetic field with an intensity <5 μT), which is known to influence the metabolic processes including mitochondria functioning. However, very few studies considering HMF impact were performed for organisms able to survive under extreme conditions and considered as suitable for outer space colonization. Therefore, we decided to check the impact of HMF on the tardigrade ''Paramacrobiotus experimentalis'' focusing on mitochondria functionality reflected by the mitochondrial inner membrane potential (ΔΨ) having regard to age and sex. '''Methods:''' Females and males from 3 different age classes (i.e., 30-60, 150-180 and >300 days) were extracted from laboratory culture and divided into experimental and control groups exposed to HMF and standard magnetic field (SMF), respectively, for three different durations i.e., 7 days, 15 days and 30 days. The HMF treatment was performed in a special anti-magnetic chamber whereas SMF treatment was performed in a climate chamber. TMRM staining of intact animals was used to estimate ΔΨ. '''Results and discussion:''' The calculated FITMRM index indicated HMF-related changes in Δψ dependent on age and sex. Accordingly, HMF effect was most pronounced for the oldest animals and males appeared to be more sensitive to HMF than females that correlated with the survival rate. The results provide an insight into mechanisms of HMF effect that could be useful for organization of space travels and living outside the Earth. # Mo W, Liu Y, He R. (2014) Hypomagnetic field, an ignorable environmental factor in space? https://doi.org/10.1007/s11427-014-4662-x# Binhi VN, Prato FS (2017) Biological effects of the hypomagnetic field: An analytical review of experiments and theories. https://doi.org/10.1371/journal.pone.0179340# Conley CC (1970) A Review of the biological effects of very low magnetic fields. NASA. Technical Note; TN D-5902: 1–27. https://ntrs.nasa.gov/citations/19700024915# Erdmann W, Idzikowski B, Kowalski W, Kosicki J, Kaczmarek Ł (2021) Tolerance of two anhydrobiotic tardigrades Echiniscus testudo and Milnesium inceptum to hypomagnetic conditions. https://doi.org/10.7717/peerj.10630scus testudo and Milnesium inceptum to hypomagnetic conditions. https://doi.org/10.7717/peerj.10630 +
'''Authors:''' [[Owesny Patricia]] … '''Authors:''' [[Owesny Patricia]], [[Hegemann N]], [[Kuebler WM]], [[Ost Mario]], [[Grune T]], [[Ott C]] Cardiac aging is a multifactorial process, which is associated with increased oxidative stress, cell death and mitochondrial abnormalities. These factors can lead to an overall impairment of cardiac function and substrate utilization [1,2]. With the increased prevalence of obesity and related comorbidities, especially coronary heart disease, it was proposed that obesity could present a condition of premature heart aging [3]. Therefore, our aim is to compare the impact of obesity and aging on heart function, as well as the cardiac energy metabolism, focusing on mitochondria. Our experimental design of diet-induced obesity contains three different age groups (22, 76 and 106 weeks), where male C57BL/6J mice receive either a High fat/High-carb or a Standard diet for 8 weeks. After dietary intervention, mice underwent echocardiographic or metabolic treadmill analysis. Heart tissue was used for the Oroboros O2k measurement of mitochondrial bioenergetics. In further studies of cardiac energy metabolism Western blot and qPCR in heart tissue and isolated cardiomyocytes were performed. Echocardiography revealed a decline in cardiac output in mice 76 and 106 weeks of age with a further decrease by High fat/High-carb diet. Interestingly, these effects were more pronounced in 76 weeks group. In the same group we investigated indications of an impaired mitochondrial energy metabolism, specifically associated with cardiomyocytes. Although, loss of cardiac function with age has been previously described, we demonstrate here a key role for mitochondrial energy metabolism in this loss of function. # Houtkooper R H, Argmann C, Houten S M, Cantó C, Jeninga E H, Andreux P A, Thomas C, Doenlen R, Schoonjans K, Auwerx J (2011), The metabolic footprint of aging in mice. https://doi.org/10.1038/srep00134. # Lazzeroni D, Villatore A, Souryal G, Pili G, Peretto G (2022), The Aging Heart: A Molecular and Clinical Challenge. https://doi.org/10.3390/ijms232416033.# Ren J, Dong F, Cai G-J, Zhao P, Nunn J M, Wold L E, Pei J (2010), Interaction between age and obesity on cardiomyocyte contractile function: role of leptin and stress signaling. https://doi.org/10.1371/journal.pone.0010085.n and stress signaling. https://doi.org/10.1371/journal.pone.0010085. +
'''Authors:''' [[Petrick Heather L]] … '''Authors:''' [[Petrick Heather L]], [[Aussieker T]], [[Fuchs CJ]], [[Hermans WJ]], [[Betz MW]], [[Pinckaers PJM]], [[Snijders T]], [[van Loon LJC]], [[Holloway Graham P]] '''Introduction:''' Mitochondrial ADP sensitivity represents an important control point in oxidative phosphorylation. The sensitivity of mitochondria to ADP is lower in high-lipid environments, in aging males, and in young females compared to young males. However, the interaction between sex, age, and body composition (fat mass) in the regulation of mitochondrial ADP sensitivity remains unknown. '''Methods:''' Vastus lateralis muscle biopsies were obtained from healthy, recreationally active, young males (n=21, 24±4 y, 22.7±2.2 kg/m2 BMI), young females (n=20, 21±2 y, 21.7±2.2 kg/m2), older males (n=13, 76±5 y, 25.8±2.5 kg/m2), and older females (n=6, 70±6 y, 23.4±3.0 kg/m2). Permeabilized fibers were prepared to measure mitochondrial ADP sensitivity. Whole-body DEXA scans were performed. Data (mean±SD) were analyzed using two-way ANOVAs. '''Results and discussion:''' Body fat percentage was higher in females and older individuals (main effects). While maximal mitochondrial respiration did not differ between groups, mitochondrial ADP sensitivity was affected by sex and age. Specifically, in younger individuals mitochondrial ADP sensitivity was lower in females compared with males (~15 % higher apparent ADP Km, p=0.02). Older males also showed ~15% lower mitochondrial ADP sensitivity compared with young males (p=0.04). In contrast to young individuals, mitochondrial ADP sensitivity was numerically greater (~15 %) in older females when compared with older males (p=0.14) and younger females (p=0.12). However, there were no correlations between body fat percentage and mitochondrial apparent ADP Km in any group. We speculate that sex-based differences in mitochondrial ADP sensitivity are impacted by estrogen as opposed to body composition, as this response is lost with aging. ADP sensitivity are impacted by estrogen as opposed to body composition, as this response is lost with aging. +
'''Authors:''' [[Phang Howard J]] … '''Authors:''' [[Phang Howard J]], [[Gerwick W]], [[Molina Anthony JA]] Mitochondrial bioenergetic decline is a well known biological hallmark of aging, suggesting that mitochondria-targeting therapeutics have great potential in treating age-related diseases and conditions [1]. Despite this, their efficacy within the context of human aging remains largely unknown. We sought to develop a phenotypic screening platform to identify agents that directly modulate mitochondrial function in human cells. Marine natural products (MNP) represent a large, under-explored chemical space with immense therapeutic potential [2]. We screened a MNP library of 125 pure compounds at 10, 1, and 0.1 µg/mL incubated for 24 hours with with primary human dermal fibroblasts (pHDF) as summarized in Figure 1. We leveraged the San Diego Nathan Shock Center which houses 50+ pHDF lines derived from healthy donors across a spectrum of adult age. Cultured pHDF retain age-related phenotypes including mitochondrial bioenergetic decline, which presents a robust opportunity to identify bioenergetic effects within the context of human aging [3]. Thus, we used pHDF from a donor representative of an “older” phenotype (74 years of age) to ensure aging relevance. We identified numerous compounds that modulate mitochondrial function in a dose-dependent manner. Our primary outcomes were change in basal or maximal respiration using high throughput respirometry (Agilent Seahorse XFe96). This screening platform successfully identified compounds with stimulatory as well as inhibitory effects on respiratory capacity. Future steps include further validation of hit compounds using high-resolution respirometry on the Oroboros O2k. These studies will elucidate mechanistic effects on the electron transfer system as well as effects on cells of different donor ages. # Murphy MP, Hartley RC (2018) Mitochondria as a therapeutic target for common pathologies. https://doi.org/10.1038/nrd.2018.174.# Liang X, Luo D, Luesch H (2018) Advances in exploring the therapeutic potential of marine natural products. https://doi.org/10.1016/j.phrs.2019.104373. # Auburger G, Klinkenberg M, Drost J, Marcus K, Morales-Gordo B, Kunz WS, Brandt U, Broccoli V, Reichmann H, Gispert S, Jendrach M (2012). Primary Skin Fibroblasts as a Model of Parkinson's Disease. https://doi.org/10.1007/s12035-012-8245-1. Parkinson's Disease. https://doi.org/10.1007/s12035-012-8245-1. +
'''Authors:''' [[Piel Sarah]] … '''Authors:''' [[Piel Sarah]], [[cManus Meagan J]], [[Heye K]], [[Beaulieu F]], [[Fazeliniae H]], [[Janowska Joanna I]], [[McTurk B]], [[Starr Jonathan]], [[Gaudio H]], [[Patel N]], [[Hefti MM]], [[Smalley M]], [[Hook JF]], [[Kohli NV]], [[Bruton J]], [[Hallowell T]], [[Delso N]], [[Roberts A]], [[Lin Y]], [[Ehinger Johannes K]], [[Karlsson Michael]], [[Berg RA]], [[Morgan RW]], [[Kilbaugh Todd J]] '''Introduction:''' Despite advancements in cardiopulmonary resuscitation (CPR), secondary neurological injury remains the key determinant of successful recovery from cardiac arrest (CA) [1-3]. Currently, there are no established clinical therapies that preserve neurological function [4]. We previously found that acute decline in mitochondrial health up to 24 hours post-CA correlated with poor neurological outcome [5-6]. Here, we tested the potential of dimethyl fumarate (DMF), a derivative of the TCA-cycle intermediate fumaric acid shown to enhance mitochondrial bioenergetics [7], to improve mitochondrial injury in brain and heart following successful resuscitation after CA. '''Methods:''' Female piglets representing toddler age underwent asphyxia, followed by ventricular fibrillation, cardiopulmonary resuscitation and defibrillation until return of spontaneous circulation. Subsequently, animals received daily treatment with DMF or vehicle. Sham animals underwent identical anesthesia protocols and instrumentation without CA. After 4 days, animals (n=5 of each group) were euthanized, tissues were harvested and their mitochondrial function, quantity and proteomic profile was analyzed. '''Results and discussion:''' Mitochondrial content and function, as measured by citrate synthase activity and high-resolution respirometry, was reduced at 4 days following CA. In contrast, myocardial mitochondria demonstrated a complete restoration of mitochondrial content and function despite persistent changes in mitochondrial ultrastructure. DMF treatment prevented 25 % of the long-term proteomic changes in the brain, including proteins related to mitochondrial bioenergetics and oxidative stress. In addition, myocardial mitochondrial morphology was normalized by DMF. In this model of CA, mitochondria sustained persistent damage in an organ-specific manner. DMF partially prevents these long-term mitochondrial changes in myocardium and brain.# Berg RA et al: Incidence and Outcomes of Cardiopulmonary Resuscitation in PICUs. Crit Care Med 2016; 44(4):798-808# Slomine BS, Silverstein FS, Christensen JR, et al: Neurobehavioural outcomes in children after In-Hospital cardiac arrest. Resuscitation 2018; 124:80-89# Laver S, Farrow C, Turner D, et al: Mode of death after admission to an intensive care unit following cardiac arrest. Intensive Care Med 2004; 30(11):2126-2128# Neumar RW et al: Post-Cardiac Arrest Syndrome. Circulation 2008; 118(23):2452-2483# Lautz AJ, Morgan RW, Karlsson M, et al: Hemodynamic-Directed Cardiopulmonary Resuscitation Improves Neurologic Outcomes and Mitochondrial Function in the Heart and Brain. Critical care medicine 2019; 47(3):e241-e249# Kilbaugh TJ, Sutton RM, Karlsson M, et al: Persistently Altered Brain Mitochondrial Bioenergetics After Apparently Successful Resuscitation From Cardiac Arrest. Journal of the American Heart Association 2015; 4(9):e002232# Hayashi G, Jasoliya M, Sahdeo S, et al: Dimethyl fumarate mediates Nrf2-dependent mitochondrial biogenesis in mice and humans. Human molecular genetics 2017; 26(15):2864-2873ice and humans. Human molecular genetics 2017; 26(15):2864-2873 +
'''Authors:''' [[Pytlak Karolina]] … '''Authors:''' [[Pytlak Karolina]], [[Maliszewska – Olejniczak K]], [[Sek Aleksandra]], [[Szewczyk Adam]], [[Bednarczyk Piotr]], [[Kulawiak Bogusz]] Human bronchial epithelial (HBE) cells form an external barrier in the airways and are constantly exposed to factors such as urban dust. Recently, the large conductance calcium-activated potassium (mitoBKCa) channel has been identified in the inner mitochondrial membrane of HBE cells. The pore-forming subunit of the channel is encoded by the ''KCNMA1'' gene, which also encodes plasma membrane BKCa channels. Mitochondrial potassium channels regulate mitochondrial membrane potential, oxygen consumption, mitochondrial volume and reactive oxygen species synthesis. Activation of mitoBKCa induces cytoprotection of cardiac and brain tissue. In our project, we applied CRISPR/Cas9 technique to disrupt ''KCNMA1'' gene in the HBE cell line (16HBE14o- cells). The newly formed line showed no mitoBKCa channel activity. We also noticed changes related to the deregulation of the cell cycle. The loss of mitoBKCa significantly affected mitochondrial function. We observed a decrease in the rate of mitochondrial respiration. Furthermore, we analyzed the organization of respiratory chain complexes using Blue Native electrophoresis. In addition, analysis of the expression of selected genes encoding mitochondrial proteins showed changes in cells with disrupted ''KCNMA1'' gene. Nevertheless, a thorough understanding of the observed mitochondrial dysfunction requires further study.We conclude that the presence of the mitoBKCa channel in HBE cells is essential for the preservation of mitochondrial function and is important for the proper function of these cells as part of the human airways. for the preservation of mitochondrial function and is important for the proper function of these cells as part of the human airways. +
'''Authors:''' [[Sadler Daniel]] … '''Authors:''' [[Sadler Daniel]], [[Treas L]], [[Ross T]], [[Sikes JD]], [[Britton SL]], [[Koch LG]], [[Borsheim Elisabet]], [[Porter Craig]] '''Introduction:''' Low cardiorespiratory fitness (CRF) is associated with a greater risk for metabolic disease. The potential for early life exercise training to overcome metabolic perturbations imparted by low intrinsic CRF remains unknown. We tested the hypothesis that early life exercise training would overcome whole-body and tissue metabolic defects imparted by low CRF.'''Methods:''' At 26 days of age, rat low-capacity runners (LCR, ''n''=20) and high-capacity runners (HCR, ''n''=20) generated by artificial selection were assigned to either sedentary control (CTRL, n=10) or voluntary wheel running (VWR, ''n''=10) for 6 weeks. Post-intervention, whole-body metabolic phenotyping was performed, and the respiratory function of isolated skeletal muscle and liver mitochondria assayed. Quantitative proteomics were performed on tissue samples.'''Results and discussion:''' HCR-VWR performed 1.8-fold greater volume of wheel running than LCR-VWR (P<0.001). In LCR, VWR reduced body fat (''P''<0.001), increased total daily energy expenditure (+16 %, ''P''=0.030), and enhanced glucose tolerance (''P''=0.040). Muscle mitochondrial respiratory function was unaffected by VWR in both strains, although VWR increased muscle mitochondrial protein content (both ''P''<0.05). VWR enhanced the respiratory capacity of HCR hepatic mitochondria (+23 %, ''P''=0.040). Proteomic analyses revealed lower capacity for fatty acid oxidation in muscle and liver of LCR-CTRL versus HCR-CTRL, which was not rescued by VWR. VWR reduced hepatic pyruvate kinase abundance in both strains (both ''P''<0.013), indicating VWR may shift fuel preferences of hepatic mitochondria. These results reveal early life exercise training partially overcomes the metabolic phenotype imparted by low intrinsic CRF, although proteomic adaptations to early exercise training remain influenced by intrinsic CRF. to early exercise training remain influenced by intrinsic CRF. +
'''Authors:''' [[Saleem Ranim]] … '''Authors:''' [[Saleem Ranim]], [[Scott Graham R]] '''Introduction:''' High-altitude environments are characterized by cold temperatures and low O2 levels (hypoxia). Small mammals at high altitude thus face the metabolic challenge of maintaining thermogenesis to cope with cold in a hypoxic environment that can constrain aerobic ATP supply. Circulatory O2 delivery by the heart is essential for supporting tissue O2 demands, but it is unclear whether evolved or plastic changes in cardiac mitochondria help overcome constraints on thermogenesis in high-altitude environments. '''Method:''' We examined this issue in deer mice (Peromyscus maniculatus). Mice from populations native to high altitude and low altitude were born and raised in captivity, and adults were acclimated to warm (25 °C) normoxia or cold (5 °C) hypoxia (~12 kPa O2 for 5-6 weeks) in a full-factorial design. Mitochondrial function was studied by high-resolution respirometry and fluorometry in permeabilized tissue from left ventricles and was complemented by assays of several metabolic and antioxidant enzymes. '''Results and discussion:''' Mitochondrial capacities for oxidative phosphorylation and electron transport were similar between populations and were unaffected by acclimation to cold hypoxia, as were activities of citrate synthase and cytochrome oxidase. However, exposure to cold hypoxia increased activities of lactate dehydrogenase, which were also greater in highlanders than in lowlanders, likely to augment capacities for lactate oxidation. Furthermore, mitochondrial emission of reactive oxygen species was lower in highlanders than in lowlanders across environments, associated with lower levels of lipid peroxidation and protein carbonyls. Therefore, phenotypic plasticity and evolved changes in cardiac mitochondria help deer mice cope with metabolic challenges at high altitude. evolved changes in cardiac mitochondria help deer mice cope with metabolic challenges at high altitude. +
'''Authors:''' [[Saucedo-Rodriguez Maria Jose]] … '''Authors:''' [[Saucedo-Rodriguez Maria Jose]], [[Pecina Petr]], [[Cunatova Kristyna]], [[Vrbacky Marek]], [[Cajka T]], [[Mracek Tomas]], [[Pecinova Alena]] '''Introduction:''' Succinate dehydrogenase (SDH) connects the TCA cycle by oxidizing succinate to fumarate and the respiratory chain by transferring electrons to ubiquinone. Mutations in SDH subunits have been associated with tumorigenesis as well as mitochondrial diseases. In this project, we focused on the flavoprotein subunit A of SDH (SDHA) which is primarily associated with inherited mitochondrial disease [1] and investigated the consequences of this subunit loss in HEK cells (SDHA KO). '''Methods:''' We performed structural and functional characterizations of the SDHA KO model involving protein electrophoresis to study OXPHOS complexes and subcomplexes, label-free quantification of protein levels, measurement of cellular respiration using high-resolution respirometry and determination of NAD+/NADH levels. '''Results and discussion:''' Together with SDHA, other SDH subunits were downregulated as well, leading to the absence of assembled SDH. Moreover, a secondary downregulation of the majority of complex I and IV subunits was observed. The cellular respiratory capacity was severely decreased in the model, with SDH-dependent respiration completely abolished and complex I-dependent respiration attenuated reflecting the downregulation of respiratory chain complexes in general. Finally, the NAD+/NADH ratio was increased in SDHA KO compared to the controls, indicating complex rearrangement of the TCA. The SDHA KO cells thus represent a suitable model to study metabolic rewiring and the effect of pathogenic SDHA mutations. # Rustin, P., Munnich, A., & Rötig, A. (2002). Succinate dehydrogenase and human diseases: new insights into a well-known enzyme. https://doi.org/10.1038/sj.ejhg.5200793 d human diseases: new insights into a well-known enzyme. https://doi.org/10.1038/sj.ejhg.5200793 +
'''Authors:''' [[Schoenfeld Peter|Schönfeld P]], … '''Authors:''' [[Schoenfeld Peter|Schönfeld P]], [[Reiser G]] Distinct hypothalamic neurons sense blood levels of fatty acids (FA) and, thereby regulate caloric intake. Astrocytes have some capacity of β-oxidation. But, there are ongoing discussions on this question: Do neurons generally burn FA for energy generation?Respiration and membrane potential of mitochondria of rat brain (RBM) and, for comparison, of liver (RLM) were measured without and with octanoate (l-octanoylcarnitine). In addition, H2O2 generation was measured with Amplex Red.In line with previous studies, we found no evidence for a noteworthy β-oxidation of FA by RBM. This fits with theoretical considerations (1) and values obtained for capacities of enzymes of β-oxidation (2). But, these results contradict those of a previous study (3), reporting that RBM incubated with mixtures of FA (carnitine derivatives) plus other substrates (e.g. succinate) show substantial β-oxidation. What could be possible reasons for disregarding FA as energy substrates by neurons? These are mainly: (a) Harmful activities of non-esterified long-chain FA on mitochondria. (b) Burning of FA costs more oxygen than glucose burning with respect to the energy yield. (c) FA oxidation by mitochondria is associated with more sites of superoxide generation. (d) Neurons are equipped with poor antioxidative capacity. In conclusion, burning of FA would expose neurons to intolerably high oxidative stress.# Speijer D (2011] Oxygen radicals shaping evolution: Why fatty acid catabolism leads to peroxisomes while neurons do without it. https://doi.org/10.1002/bies.201000097# Yang SY, He XY, Schultz H (1987) Fatty acid oxidation in rat brain is limited by the low activity of 3-ketoacyl-coenzyme A thiolase. https://doi.org/10.1016/S0021-9258(18)45161-7# Panov A, Orynbayeva Z, Vavilin V, Lyakhovich V (2014) Fatty acids in energy metabolism of the central nervous system. https://doi.org/10.1155/2014/472459tabolism of the central nervous system. https://doi.org/10.1155/2014/472459 +
'''Authors:''' [[Sobotka Lubos]] … '''Authors:''' [[Sobotka Lubos]], [[Sobotka Ondrej]] Obesity is associated with insulin resistance, which is the cause of subsequent metabolic complications, including increased morbidity. Despite several decades of efforts to prevent the growth of obesity, its incidence continues to increase. We do not even know what ratio of nutrients is optimal for preventing obesity and insulin resistance, and the optimal ratio of carbohydrates to lipids has not been proven. Some studies, including calorimetric measurements performed at our workplace, have shown that the oxidation of individual substrates does not correspond to their ratio in the given diet. However, this apparent paradox makes sense because food intake in humans is intermittent and usually does not occur during increased or even maximal physical activity. Energy and metabolic substrates are stored in the body during intake and are subsequently mobilized during periods of starvation and physical activity. As a result, the human body is never in true energy balance; storage and subsequent mobilization of energy is necessary for a functioning organism. In addition, carbohydrates, fats and proteins are not only a source of energy, but also important substances with many functions [1]. After ingestion of a mixed meal, carbohydrates (especially glucose) are used for both oxidation and non-oxidative pathways (antioxidant, anaplerotic, cataplerotic processes). Only a relatively small fraction of glucose is a source for new lipid synthesis. Ingested fats are preferentially stored in adipose tissue and does not influence carbohydrate oxidation. The lack of glucose can explain more insulin resistance in whole organism than Randle cycle measured in vitro conditions [2].# Sobotka L, Sobotka O. The predominant role of glucose as a building block and precursor of reducing equivalents. https://doi.org/10.1097/mco.0000000000000786 # Sobotka O, et al. Should Carbohydrate Intake Be More Liberal during Oral and Enteral Nutrition in Type 2 Diabetic Patients? https://doi.org/10.3390/nu15020439in Type 2 Diabetic Patients? https://doi.org/10.3390/nu15020439 +
'''Authors:''' [[Stanic Sara]] … '''Authors:''' [[Stanic Sara]], [[Janovska Petra]], [[Zouhar Petr]], [[Bardova K]], [[Otahal J]], [[Vrbacky Marek]], [[Mracek Tomas]], [[Adamcova K]], [[Lenkova L]], [[Funda J]], [[Cajka T]], [[Drahota Zdenek]], [[Rustan Arlid C]], [[Horakova Olga]], [[Houstek Josef]], [[Rosmeissl M]], [[Kopecky Jan]] '''Introduction:''' Non-shivering thermogenesis (NST) is an energy-dissipating process that occurs in brown adipose tissue (BAT) and is activated by the adrenergic system. Earlier studies found that cold induces adrenergically activated NST in obesity-prone C57BL/6 (B6) mice, but not in obesity-resistant A/J mice. To investigate this difference, we studied the effect of cold acclimation on muscle NST. '''Methods:''' Palmitoyl carnitine oxidation and cytochrome c oxidase (COX) activity (TMPD+ascorbate and KCN) was measured in muscle homogenates of A/J and B6 mice acclimated to 30 °C or to 6 °C using Oroboros Oxygraph. In parallel, amount of mitochondrial supercomplexes was assessed by Blue native electrophoresis. '''Results and discussion:''' As expected, muscle of A/J mice exhibited higher amount of Scaf1 dependent supercomplex III2IV than muscle of B6 mice, and this amount was further increased by cold acclimation. Both palmitoyl carnitine oxidation and COX activity were induced by cold in A/J but not in B6 mice. The higher oxidation capacity of muscle of cold acclimated A/J mice, possibly connected with supercomplex composition, may indicate that muscle represents the site of alternative NST instead of BAT in these mice. The distinct mechanism of NST could correspond to obesity resistance of this strain. # Janovska P. et al (2023) Impairment of adrenergically-regulated thermogenesis in brown fat of obesity-resistant mice is compensated by non-shivering thermogenesis in skeletal muscle. https://doi.org/10.1016/j.molmet.2023.101683rmogenesis in skeletal muscle. https://doi.org/10.1016/j.molmet.2023.101683 +
'''Authors:''' [[Stankova Pavla]] … '''Authors:''' [[Stankova Pavla]], [[Peterova E]], [[Dusek J]], [[Elkalaf Moustafa]], [[Cervinkova Zuzana]], [[Kucera Otto]] '''Introduction:''' In our previous study in a murine model of nonalcoholic steatohepatitis (NASH), we found reduced succinate-activated hepatic mitochondrial respiration and accumulation of succinate, a proinflammatory, profibrogenic, and oncogenic metabolite [1]. According to preliminary studies, telmisartan, an angiotensin II type 1 receptor blocker, positively affects insulin resistance and liver steatosis. This project aimed to investigate the effect of telmisartan on NASH in mice. '''Methods:''' The NASH was induced in male mice fed a western-style diet (WD) for 36 weeks. During the last 6 weeks of the experiments, mice were administered daily telmisartan (oral gavage, 5 mg/kg b.w./day). Liver and epididymal fat histological changes were evaluated (Hematoxylin-eosin, Sirius red). Body parameters, plasma liver profile (VetScan), hepatic triglycerides, cholesterol, and the expression of selected proteins (WB/ELISA) and genes (qRT-PCR) were assessed. Mitochondrial respiration of liver homogenates was measured by high-resolution respirometry (OROBOROS Oxygraph-2k). Using Reporter Gene assay, telmisartan's activation of nuclear receptors was evaluated on HepG2 cells. '''Results and discussion:''' Administration of telmisartan to mice fed a WD reduced absolute and relative liver weight and visceral adipose tissue weight, activities of ALT and AST, liver steatosis, and inflammation grade. These effects were accompanied by a significant increase in succinate-activated respiration in the ET state and the activity of succinate dehydrogenase. We confirmed that telmisartan is a PPAR-γ partial agonist and described the activating effect of telmisartan on the CAR receptor for the first time. Telmisartan appears to be a promising safety drug for treating NASH that affects metabolism at multiple levels. # Staňková P, Kučera O, Peterová E, Elkalaf M, Rychtrmoc D, Melek J, Podhola M, Zubáňová V, Červinková Z (2021) Western Diet Decreases the Liver Mitochondrial Oxidative Flux of Succinate: Insight from a Murine NAFLD Model. https://doi.org/10.3390/ijms22136908ght from a Murine NAFLD Model. https://doi.org/10.3390/ijms22136908 +
'''Authors:''' [[Stiles Linsey]] … '''Authors:''' [[Stiles Linsey]], [[Fernandez-del-Rio L]], [[Beninca C]], [[Acin-Perez R]], [[Shirihai Orian]] Impaired mitochondrial function has been shown to play a key role in diseases of metabolism and aging. Respirometry is the gold standard measurement of mitochondrial function, as it is an integrated metabolic readout of the final step of the electron transport chain (ETC). However, analysis of mitochondrial respiratory function in tissue requires processing and measurement of freshly isolated mitochondria. This requirement makes respirometry impracticable for standard clinical practice, clinical studies, retrospective studies, and higher throughput respirometry. We have validated a methodology to measure maximal mitochondrial oxygen consumption rates through Complex I, II, and IV of the ETC in previously frozen biological samples using Agilent XF Analyzers. Additionally, Complex V (CV) ATP hydrolytic activity can be measured with the pH channel. These measurements of Complex I-V activities are specific as demonstrated by inhibition with ETC inhibitors. Additionally, these approaches can be applied to tissue homogenates, which simplifies the sample preparation and reduces the required starting material compared with isolating mitochondria. We find that primary changes in the maximal respiratory capacity, detected in fresh tissue, are preserved in frozen samples. These techniques to measure mitochondrial maximal respiratory function and CV hydrolytic activity in frozen samples makes clinical mitochondrial assessment more feasible and adds a complementary approach to investigate the role of mitochondrial function in disease onset and progression.tochondrial function in disease onset and progression. +
'''Authors:''' [[Timon-Gomez Alba]] … '''Authors:''' [[Timon-Gomez Alba]], [[Cardoso Luiza HD]], [[Doerrier Carolina]], [[Garcia-Souza Luiz F]], [[Gnaiger Erich]] '''Introduction:''' Mitochondrial dysfunction in muscle tissue is associated with obesity (mitObesity) and its comorbidities. Many drugs and nutraceuticals used to treat these conditions target mitochondria. Early diagnosis of mitObesity is crucial for understanding the link between obesity, mitochondrial dysfunction, and its associated chronic comorbidities. Respirometry of mitochondrial preparations can assess electron transfer pathways and coupling in oxidative metabolism with high diagnostic resolution [1]. '''Methods:''' We developed a standardized protocol for functional diagnosis of mitochondrial defects using high-resolution respirometry [2]. This substrate-uncoupler-inhibitor titration (SUIT) protocol analyzes fatty acid oxidation (FAO) by adding 0.1 mM malate and octanoylcarnitine, with consideration of malate-linked anaplerosis to avoid overestimation of FAO [3-4]. The protocol is extended to stimulate the NADH-linked pathway by adding pyruvate and glutamate. Then succinate and glycerophosphate are titrated to investigate convergent CoQ-reducing pathways. A stepwise titration of uncoupler CCCP allows quantification of the electron transfer capacity. Residual oxygen consumption is assessed after inhibition by rotenone and antimycin A. '''Results and discussion:''' To quantify FAO, malate was needed to avoid inhibition by accumulating acetyl-CoA. However, in the presence of mitochondrial malic enzyme, 2 mM malate stimulated respiration through the NADH-linked pathway in liver and brain mitochondria. Anaplerotic activity above endogenous respiration was minimized at a low (0.1 mM) malate concentration and subtracted from respiration obtained after addition of octanoylcarnitine. This SUIT reference protocol can be used as a general diagnostic tool for bioenergetic profiling in various sample preparations from different cell types, tissues, and organisms. # Gnaiger E (2020) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 5th ed. https://doi.org/10.26124/bec:2020-0002# Doerrier C, Garcia-Souza LF, Krumschnabel G, Wohlfarter Y, Mészáros AT, Gnaiger E (2018) High-Resolution FluoRespirometry and OXPHOS protocols for human cells, permeabilized fibers from small biopsies of muscle, and isolated mitochondria. https://doi.org/10.1007/978-1-4939-7831-1_3 # Ojuka E, Andrew B, Bezuidenhout N, George S, Maarman G, Madlala HP, Mendham A, Osiki PO (2016) Measurement of β-oxidation capacity of biological samples by respirometry: a review of principles and substrates. https://doi.org/10.1152/ajpendo.00475.2015# Bernstine EG, Koh C, Lovelace CC (1979) Regulation of mitochondrial malic enzyme synthesis in mouse brain. https://www.doi.org/10.1073/pnas.76.12.6539synthesis in mouse brain. https://www.doi.org/10.1073/pnas.76.12.6539 +
'''Authors:''' [[Torres-Quesada Omar]] … '''Authors:''' [[Torres-Quesada Omar]], [[Strich Sophie]], [[Feichtner Andreas]], [[Schwaighofer Selina]], [[Doerrier Carolina]], [[Schmitt Sabine]], [[Gnaiger Erich]], [[Stefan Eduard]] Protein kinases play an important role in numerous signaling pathways regulating cell proliferation, cell cycle, and metabolism. Deregulation of kinase functions have been connected to various human diseases, such as cancer [1]. In recent years, kinase inhibitors have gained recognition by aiming to block single or multiple oncogenic kinase pathways [2]. In these lines, blockade of kinase activities has been shown to converge on the central energetic organelle, the mitochondria [3, 4]. Furthermore, colon cancer cells rely on mitochondrial OXPHOS as major source of energy, contradicting the Warburg effect [5]. To increase the understanding of small molecule-based kinase blockers and their cell-type-specific adverse effects, we set out to record the impact of kinase drugs on mitochondrial respiration using High-resolution FluoRespirometry in several colon cancer cell models. We observed that the impact of kinase inhibitors depends on the mutational background of the tested cancer cell lines as well as on cell culture medium formulations [6]. First, we detected off-target effects of sunitinib, an FDA-approved multikinase blocker, only in a more physiological cell culture medium as compared with classical formulations. Second, mitochondrial profiling of the glycolytic kinase inhibitor PFK158 revealed off-target mitochondrial dysfunction. Third, we were able to show that inhibition of kinase signaling is connected to mitochondrial reactive oxygen species (ROS), which can be influenced by protein kinase modulators. In summary, cell-based mitochondrial bioenergetic profiles have the power to identify off-target effects of kinase inhibitors and allow a detailed mechanistic insight on drug-induced perturbations in cancer cell metabolism.# Cohen, P, Cross, D, Jänne, PA (2021). Kinase drug discovery 20 years after imatinib: progress and future directions. Nat Rev Drug Discov. 20(7):551-569. https://doi.org/10.1038/s41573-021-00195-4 # Zhang J, Yang PL, Gray NS (2009). Targeting cancer with small molecule kinase inhibitors. https://doi.org/10.1038/nrc2559 # Wallace, DC (2012). Mitochondria and Cancer Nat. Rev. Cancer, 12, 685–698. https://doi.org/10.1038/nrc3365 # Torres-Quesada O, Strich S, Stefan E (2022). Kinase perturbations redirect mitochondrial function in cancer. Bioenerg. Commun. 2022,13. https://doi.org/10.26124/bec:2022-0013# Sun, X., Zhan, L., Chen, Y. et al. (2018) Increased mtDNA copy number promotes cancer progression by enhancing mitochondrial oxidative phosphorylation in microsatellite-stable colorectal cancer. Sig Transduct Target Ther 3, 8. https://doi.org/10.1038/s41392-018-0011-z # Torres-Quesada, O, Doerrier, C, Strich, S, Gnaiger, E, Stefan, E (2022). Physiological Cell Culture Media Tune Mitochondrial Bioenergetics and Drug Sensitivity in Cancer Cell Models. Cancers, 14, 3917. https://doi.org/10.3390/cancers14163917ancers, 14, 3917. https://doi.org/10.3390/cancers14163917 +
'''Authors:''' [[Ullrich Volker]] … '''Authors:''' [[Ullrich Volker]], [[Heidler Juliana]], [[Schildknecht S]], [[Daiber Andreas]], [[Frensch M]], [[Wittig Ilka]], [[Bruene B]] '''Introduction:''' Micelles containing cardiolipin (CL) and phosphatidylcholine in presence of cytochrome ''c'' (Cytc) and H2O2 were reported to catalyze peroxidationes of typical peroxidase substrates but also of CL itself (Kagan et. al, Biochem. 45,4998, 2006). This can be explained by complex formation of CL with Cytc under removal of the Met80 sixth ligand of the heme. '''Methods:''' O2 consumption was measured polarographically (Orobos Instruments) and diene formation spectrally at 237 nm. '''Results and Discussion:''' Cytc addition to CL micelles caused a burst of O2 uuptake that could be repeated until CL or O2 were depleted. About 4.5 mol of O2/mol CL were taken up forming products with mainly 2,4,6 or 8 additional O-atoms. Diene formation initially followed the same kinetics but stopped or was reversed before O2 uptake was completed. In presence of 2 M KCl Cytc acted catalytically with slower kinetics in three phases and showed oxidative modifications of the protein. The required peroxide tone originated from autoxidized CL and was upregulated during progress of the reaction. Significance for the process of opening of the permeability pore is suggested. autoxidized CL and was upregulated during progress of the reaction. Significance for the process of opening of the permeability pore is suggested. +
'''Authors:''' [[Valencia Ana P]] … '''Authors:''' [[Valencia Ana P]], [[Melhorn Susan J]], [[Schur Ellen A]], [[Marcinek David J]] '''Introduction:''' Weight loss (WL) promotes counterregulatory mechanisms that may involve mitochondrial (MITO) function to limit cardiometabolic benefit. This study compared T-cell MITO function in states of obesity (OB), active weight loss (OB-WL), weight loss plateau (OB-PL), regain (OB-RG), and healthy weight (HWC). '''Methods:''' Participants with obesity (61.5%female, 39.5±10.8 yr, BMI 36.7±6.4) underwent a 24-week WL intervention and transmitted their daily weight for 18 months. T-cells (CD3+) were isolated from blood samples obtained at baseline, 6-month, or 12-months. We measured MITO respiratory capacity (MITO-RC) (XFe Analyzer) and sensitivity of membrane depolarization with ADP (IC50) (O2K Fluorespirometer). '''Results:''' Compared to HWC, MITO-RC was lower in OB T-cells (4.1±1.7 vs. 3.3±1.0 pmol O2/106 cells, p<0.05), and even lower in OB-PL (3.0±0.7, p<0.05) and OB-RG (2.7±0.3, p<0.05). Maximal membrane potential was also lower in the OB group and remained low in all phases of WL. IC50 did not differ in T-cells between HWC and OB but was lower in OB-WL and OB-PL (156±15 vs. 7±1 & 22±5, p<0.05). '''Conclusions:''' T-cell MITO respiratory capacity is reduced in obesity and further aggravated in response to WL, particularly following a plateau. However, WL improved ADP sensitivity, suggesting a potential counterregulatory mechanism to meet energy demand. Findings suggest that the MITO function of T-cells is not restored by WL to resemble HWC and is rather altered in a way that could potentially limit cardiometabolic benefit of WL. L to resemble HWC and is rather altered in a way that could potentially limit cardiometabolic benefit of WL. +
'''Authors:''' [[Vujacic-Mirski Ksenija]] … '''Authors:''' [[Vujacic-Mirski Ksenija]], [[Sudowe S]] The impairment of mitochondrial respiration, observed in neurodegenerative and cardiovascular disease, diabetes, cancer and migraine headaches, has emerged as a biomarker of mitochondrial dysfunctions [1]. Newer research are also trying to link conditions such as chronic fatigue, depression and other behaviour/mood disorders with mitochondrial malfunctioning [2]. In our study, we examined 88 (relatively) healthy volunteers, ages from 23 to 68, from which 36 individuals were taking some sort of medication (such as for asthma, high blood pressure, mood disorders), but they considered themselves fit and healthy. Volunteers were ask to follow their normal routines day prior the test. The blood was drawn 3 h before PBMCs isolation, followed by immediate Seahorse XF Cell Mito Stress Test (Agilent) on SeahorseXF96e instrument (Agilent). Our analysis consisted of carefully examining parameters of mitochondrial respiration: basal respiration, ATP-linked respiration, reserve capacity, maximal respiration, proton leak, non-mitochondrial respiration as well as bioenergetics health index (BHI) [3]. We observed difference between people who took some sort of medication for chronic but manageable comorbidities and completely healthy individuals. There was significant difference between BHI, reserve capacity, coupling efficiency and proton leak. We also observed that people who had regular sport activities (in the healthy group without any medication) seem to have lower proton leak. This difference was not significant but points out to the lifestyle impact to mitochondria [4]. # Petrus, A T et al. (2019) Assessment of platelet respiration as emerging biomarker of disease. https://doi.org/10.33549/physiolres.934032# Zvěřová M et al. (2019) Disturbances of mitochondrial parameters to distinguish patients with depressive episode of bipolar disorder and major depressive disorder. https://doi.org/10.2147/NDT.S188964# Chacko, Balu K et al. (2014) The Bioenergetic Health Index: a new concept in mitochondrial translational research. https://doi.org/10.1042/CS20140101 # Janssen, Joëlle J E et al. (2022) Extracellular flux analyses reveal differences in mitochondrial PBMC metabolism between high-fit and low-fit females. https://doi.org/10.1152/ajpendo.00365.2021w-fit females. https://doi.org/10.1152/ajpendo.00365.2021 +
'''Authors:''' [[Whitcomb Luke A]] … '''Authors:''' [[Whitcomb Luke A]], [[Li Puma Lance C]], [[Zilhaver PT]], [[Izon CS]], [[Chicco Adam J]] Myocardial ischemia causes pathological increases in cardiomyocyte mitochondrial calcium (Ca++), which trigger a series of events that contribute to cell death and myocardial necrosis. Previous studies in our lab and others indicate that metabolites of phosholipid-derived arachidonic acid (AA), an omega-6 polyunsaturated fatty acid (PUFA), contribute to mitochondrial permeability transition pore (mPTP) opening in response to Ca++ overload, leading to mitochondrial swelling, rupture, and release of reactive oxygen species (ROS) [1,2]. We hypothesized that age-related increases in these parameters result in part from greater mitochondrial production of AA from its abundant membrane PUFA precursor linoleic acid (LA) in response to Ca++ overload. To test this hypothesis, we evaluated effects of 50-400 µM Ca++ on O2 consumption, ROS release and mPTP opening in cardiac mitochondria isolated from young (3 mo) and aged (24 mo) BALB/c mice in the presence or absence of an inhibitor of delta-6 desaturase (D6D), the rate-limiting enzyme in AA biosynthesis from LA. Results demonstrate that cardiac mitochondria from old mice release more ROS during oxidative phosphorylation and undergo more mPTP opening in response to Ca++ overload than mitochondria from young mice. D6D inhibition significantly attenuates these responses in both young and old mitochondria, but had greater impacts on old, largely abolishing the effect of aging on both ROS release and mPTP opening. Similar attenuation of mPTP opening was seen following inhibition of lipoxygenase enzymes (Baicalein), consistent with the hypothesized links between mitochondrial AA synthesis, eicosanoid production and mPTP in regulating responses of cardiac mitochondria to Ca++ overload. # Moon SH, Jenkins CM, Liu X, Guan S, Mancuso DJ, Gross RW (2012) Activation of mitochondrial calcium-independent phospholipase A2 gamma by divalent cations mediating arachidonate release and production of downstream eicosanoids. https://10.1074/jbc.M111.336776 # Moon SH, Jenkins CM, Kiebish MA, Sims HF, Mancuso DJ, Gross RW (2012) Genetic Ablation of Calcium-independent Phospholipase A2γ (iPLA2γ) attenuates calcium-induced opening of the mitochondrial permeability transition pore and resultant cytochrome ''c''. https://doi.org/10.1074/jbc.M112.373654 uced opening of the mitochondrial permeability transition pore and resultant cytochrome ''c''. https://doi.org/10.1074/jbc.M112.373654 +
'''Authors:''' [[Wohlfarter Yvonne]] … '''Authors:''' [[Wohlfarter Yvonne]], [[Eidelpes R]], [[Yu RD]], [[Sailer S]], [[Koch Jakob]], [[Karall Daniela]], [[Scholl‑Buergi S]], [[Amberger A]], [[Hillen HS]], [[Zschocke J]], [[Keller Markus A]] '''Introduction:''' Human 17β-Hydroxysteroid dehydrogenase 10 (HSD10) is a crucial enzyme located in mitochondria that participates in isoleucine catabolism and is part of the mitochondrial RNase P complex [1,2]. Mutations in the ''HSD10B17'' gene have been linked to HSD10 disease, which causes progressive cardiomyopathy and cognitive function loss [3]. Recently, HSD10 has been reported to possess a phospholipase C-like activity towards cardiolipins, which are essential mitochondrial membrane lipids involved in various processes such as super-complex assembly, cristae formation, and apoptotic signaling cascades [4]. The transacylase tafazzin is remodeling cardiolipin side chains, and its deficiency leads to high levels of monolyso-cardiolipins and abnormal cardiolipin patterns [5]. '''Methods:''' To explore the role of HSD10 in cardiolipin homeostasis, we carried out a comprehensive analysis of cardiolipin profiles in different cellular contexts by means of LC-MS/MS [6]: We investigated the impact of HSD10 knockdown in wild-type cells, in a tafazzin-deficient background, and in fibroblasts derived from HSD10-deficient patients. Additionally, by supplementation with fatty acids such as linoleic acid and palmitic acid we simulated different lipid environments. '''Results and Discussion:''' We found no evidence for the enzyme function of HSD10 to be involved in cardiolipin homeostasis in all conditions examined [6]. Thus, its previously reported cardiolipin cleaving function is likely to be regarded as an ''in vitro'' artefact. However, the HSD10's structural importance in the mitochondrial RNase P complex underscores its essential role in cellular function [7]. We show that the enzyme has evolved with significant evolutionary constraints to maintain this structure, possibly at the expense of achieving a high degree of substrate specificity and reaction rates [6].# Zschocke J, Ruiter JPN, Brand J, et al (2000) Progressive Infantile Neurodegeneration Caused by 2-Methyl-3-Hydroxybutyryl-CoA Dehydrogenase Deficiency: A Novel Inborn Error of Branched-Chain Fatty Acid and Isoleucine Metabolism. https://doi.org/10.1203/00006450-200012000-00025# Bhatta A, Dienemann C, Cramer P, Hillen HS. (2021) Structural basis of RNA processing by human mitochondrial RNase P. https://doi.org/10.1038/s41594-021-00637-y# Zschocke J. (2012) HSD10 disease: clinical consequences of mutations in the HSD17B10 gene. https://doi.org/10.1007/s10545-011-9415-4# Boynton TO, Shimkets LJ. (2015) Myxococcus CsgA, Drosophila Sniffer, and human HSD10 are cardiolipin phospholipases. https://doi.org/10.1101/gad.268482.115# Oemer G, Koch J, Wohlfarter Y, Lackner K, Gebert REM, Geley S, et al. (2022) The lipid environment modulates cardiolipin and phospholipid constitution in wild type and tafazzin-deficient cells. https://doi.org/10.1002/jimd.12433# Wohlfarter Y, Eidelpes R, Yu RD, Sailer S, Koch J, Karall D, et al. (2022) Lost in promiscuity? An evolutionary and biochemical evaluation of HSD10 function in cardiolipin metabolism. https://doi.org/10.1007/s00018-022-04682-8# Zschocke J, Byers PH, Wilkie AOM. (2023) Mendelian inheritance revisited: dominance and recessiveness in medical genetics. https://doi.org/10.1038/s41576-023-00574-0 n medical genetics. https://doi.org/10.1038/s41576-023-00574-0 +
'''Authors:''' [[Yardeni Tal]] … '''Authors:''' [[Yardeni Tal]] Both mitochondrial DNA (mtDNA) lineages and the gut microbiota have been correlated with altered risk for a variety of human diseases including obesity. However, the mechanisms by which mtDNA variation and the gut microbiota modulate disease risk remains unknown. Our hypothesis is that both the gut microbiota and the immune system are modulated by the mitochondrial genome, in part through mitochondrial reactive oxygen species (mtROS) production, forming a critical link between the gut microbiota and disease initiation and progression.Our studies showed significant differences in gut microbiota in our conplastic mice which differ in their mtDNA lineages. Further, the transfer of the gut microbiota from a host of one mitochondrial genotype to a host of different mitochondrial genotypes shifted the gut microbiota composition toward that of the recipient animal. Moreover, we showed that host mtROS levels modulated the composition of the gut microbiota. Those conplastic mice also exhibit markedly different capacities to sustain melanoma tumor growth. Relative to control mtDNA (mtDNAB6) mice, the mice harboring NZB mtDNAs (mtDNANZB) have strong anti-tumor immune response while those with129 mtDNA (mtDNA129) are the opposite. Reduction of mtROS by expression of mitochondrial catalase (mtCAT)Tg only in the hematopoietic cells changed the gut microbiota and obviated the anti-tumor effects on the mtDNANZB and mtDNAB6 mice. These observations suggest that disease severity (melanoma), and gut microbiota are regulated by the mtDNA's regulation of mtROS production in host immune cells, pointing to new potential pathways for understanding diseases etiology.lation of mtROS production in host immune cells, pointing to new potential pathways for understanding diseases etiology. +
'''Authors:''' [[Zweck Elric]] … '''Authors:''' [[Zweck Elric]], [[Piel Sarah]], [[Chadt A]], [[Al-Hasani H]], [[Kelm M]], [[Szendroedi Julia]], [[Roden Michael]], [[Granata Cesare]] '''Introduction:''' Ketone bodies (KB) are important substrates for the heart, particularly during heart failure [1], kidney [2], brain, skeletal muscle, and other organs [3]. Despite their significant role in health and disease [4], very limited research is available investigating KB-linked ATP production in mammalian tissues [5]; moreover, no optimized protocols exist to assess the interplay of key enzymes involved in ketolysis and their respective contribution to OXPHOS capacity. '''Methods:''' β-hydroxybutyrate (HBA)- and acetoacetate (ACA)-linked mitochondrial respiration was assessed in the heart left ventricle (LV), kidney, liver, brain, and soleus of ~18-24-week-old C57BL/6J female mice (n=6-8). A novel protocol combining KB-linked and complex I (CI)+CII-linked mitochondrial respiration was also devised. '''Results and discussion:''' The Km for HBA was similar (~1 mM) in all tested organs. However, maximal HBA-linked respiration was different between organs (p<0.001), i.e., greater in the LV and liver (~32 pmol O2·s-1·mg-1), and lowest in the brain (5.2 pmol O2·s-1·mg-1). This protocol allows to determine β-hydroxybutyrate dehydrogenase activity in the liver. The Km for ACA and maximal ACA-linked respiration were greater in the kidney compared to the other tested organs (all p<0.050). Our novel KB+CI+CII combined respiration protocol indicated that the KB contribution to maximal respiration is 2- to 4-fold greater in the kidney (37.4 %) compared to all other organs (all p<0.050), confirming the kidney’s reliance on KB metabolism [2]. Taken together, our novel protocols demonstrate an organ-specific response of mitochondrial respiration to different KBs. # Aubert, G., et al., The failing heart relies on ketone bodies as a fuel. Circulation, 2016. 133(8): p. 698-705. https://doi.org/10.1161/CIRCULATIONAHA.115.017355# Forbes, J.M. and D.R. Thorburn, Mitochondrial dysfunction in diabetic kidney disease. Nature Reviews Nephrology, 2018. 14(5): p. 291-312. https://doi.org/10.1038/nrneph.2018.9# Robinson, A.M. and D.H. Williamson, Physiological roles of ketone bodies as substrates and signals in mammalian tissues. Physiological reviews, 1980. 60(1): p. 143-187. https://doi.org/10.1152/physrev.1980.60.1.143# Puchalska, P. and P.A. Crawford, Metabolic and signaling roles of ketone bodies in health and disease. Annual review of nutrition, 2021. 41: p. 49-77. https://doi.org/10.1146/annurev-nutr-111120-111518# Petrick, H.L., et al., In vitro ketone‐supported mitochondrial respiration is minimal when other substrates are readily available in cardiac and skeletal muscle. The Journal of Physiology, 2020. 598(21): p. 4869-4885. https://doi.org/10.1113/JP280032en other substrates are readily available in cardiac and skeletal muscle. The Journal of Physiology, 2020. 598(21): p. 4869-4885. https://doi.org/10.1113/JP280032 +
'''Authors:'''[[Kolonics Attila]] … '''Authors:'''[[Kolonics Attila]], [[Kawamura T]], [[Szipoecs R]], [[Radak Z]] Aging leads to a loss of muscle mass and a decline in skeletal muscle function (1) leading to imbalance between glucose and lipid metabolism (2). Low exercise capacity is highly correlated with skeletal muscle dysfunction and metabolic disorders (3). Age-associated factors intrinsic to the muscle, including defects in NAD+ synthesis (4), reduced mitochondrial copy number (5), and epigenomic changes affecting the expression of metabolic genes (6) reported. We aimed to characterize mitochondrial fitness of liver in an inborn low- versus high-capacity runners (LCR/HCR) aged female rats to study the spread of metabolic dysfunction. LCR/HCR rats (44th generation, 24 months old) used were artificially selected from genetically heterogeneous N:NIH stock (7). NAD(P)H lifetime imaging (FLIM) characterized liver metabolism in frozen tissues; basal and succinate induced ROS production was evaluated by Amplex Red in the presence of horseradish peroxidase, ΔΨmt by TMRE in intact liver mitochondria. HCR group was less vulnerable to metabolic disorder comparing to LCR group proofed by decreased body mass and increased VO2max. It was further supported by mitochondrial analysis of intact liver mitochondria. Basal ROS production showed no difference between LCR and HCR groups although succinate induced ROS production was higher in LCR group at identical ΔΨmt. NAD(P)H FLIM uncovered subtle alterations: LCR groups had significantly less free NADH comparing to HCR groups (Fig.1). In conclusion, epigenetic changes induced decline of metabolism correlated with deterioration of liver mitochondrial fitness. Succinate induced ROS-production at same membrane potential negatively correlated with free NADH-level. # Frontera WR, Hughes VA, Lutz KJ, Evans WJ (1985) A cross-sectional study of muscle strength and mass in 45- to 78-yr-old men and women. J Appl Physiol. 1991 Aug;71(2):644-50 http://doi.org/10.1152/jappl.1991.71.2.644 # Gheller BJ, Riddle ES, Lem MR, Thalacker-Mercer AE (2016) Understanding Age-Related Changes in Skeletal Muscle Metabolism: Differences Between Females and Males. Annu Rev Nutr. 2016 Jul 17;36:129-56 http://doi.org/10.1146/annurev-nutr-071715-050901# Biolo G, Cederholm T, Muscaritoli M (2014) Muscle contractile and metabolic dysfunction is a common feature of sarcopenia of aging and chronic diseases: from sarcopenic obesity to cachexia. Clin Nutr. 2014 Oct;33(5):737-48 http://doi.org/10.1016/j.clnu.2014.03.007# Yoshino J, Mills KF, Yoon MJ, Imai S (2011) Nicotinamide mononucleotide, a key NAD(+) intermediate, treats the pathophysiology of diet- and age-induced diabetes in mice. Cell Metab. 2011 Oct 5;14(4):528-36 http://doi.org/10.1016/j.cmet.2011.08.014# Barazzoni R, Short KR, Nair KS (2000) Effects of aging on mitochondrial DNA copy number and cytochrome c oxidase gene expression in rat skeletal muscle, liver, and heart. J Biol Chem. 2000 Feb4; 275(5): 3343-7 http://doi.org/10.1074/jbc.275.5.3343# Jiang MH, Fei J, Lan MS, Lu ZP, Liu M, Fan WW, Gao X, Lu DR (2008) Hypermethylation of hepatic Gck promoter in ageing rats contributes to diabetogenic potential. Diabetologia. 2008 Aug;51(8):1525-33 http://doi.org/10.1007/s00125-008-1034-8# Koch LG, Britton SL (2007) Artificial selection for intrinsic aerobic endurance running capacity in rats. Physiol Genomics. 2001 Feb 7;5(1):45-52 http://doi.org/10.1152/physiolgenomics.2001.5.1.45 running capacity in rats. Physiol Genomics. 2001 Feb 7;5(1):45-52 http://doi.org/10.1152/physiolgenomics.2001.5.1.45 +
'''Authours:''' [[Kayastha Pushpalata]] … '''Authours:''' [[Kayastha Pushpalata]], [[Wieczorkiewicz Filip]], [[Kaczmarek Lukasz]], [[Poprawa Izabela]] Tardigrada (water bears) are well known for their ability to undergo cryptobiosis and survival in extreme conditions. The best-known type of cryptobiosis for their survival is anhydrobiosis i.e. response to lack of water. In this state tardigrades are able to tolerate high pressure, very high and low temperatures, space vacuum, and high levels of UV, and ionizing radiation. These results in various ultrastructural changes in tardigrades, including in mitochondria. We analyzed the effect of different temperatures (20 °C, 35 °C, 37 °C, 40 °C and 42 °C) on the ultrastructure of mitochondria in the tardigrade ''Paramacrobiotus experimentalis'' Kaczmarek et al. 2020. Analyzes were conducted in active specimens, specimens in anhydrobiosis (tun), and rehydrated specimens. The analysis will provide knowledge about changes in the ultrastructure of tardigrades caused by different temperatures. Our results will also determine whether anhydrobiosis protects against temperature-induced ultrastructural changes.s against temperature-induced ultrastructural changes. +
'''BACKGROUND & AIMS:''' Liver ischemi … '''BACKGROUND & AIMS:''' Liver ischemia/reperfusion (I/R) injury is a frequent cause of organ dysfunction. Loss of the oxygen sensor prolyl hydroxylase domain enzyme 1 (PHD1) causes tolerance of skeletal muscle to hypoxia. We assessed whether loss or short-term silencing of PHD1 could likewise induce hypoxia tolerance in hepatocytes and protect them against hepatic I/R damage.'''METHODS:''' Hepatic ischemia was induced in mice by clamping of the portal vessels of the left lateral liver lobe; 90 minutes later livers were reperfused for 8 hours for I/R experiments. Hepatocyte damage following ischemia or I/R was investigated in PHD1-deficient (PHD1(-/-)) and wild-type mice or following short hairpin RNA-mediated short-term inhibition of PHD1 ''in vivo''.'''RESULTS:''' PHD1(-/-) livers were largely protected against acute ischemia or I/R injury. Among mice subjected to hepatic I/R followed by surgical resection of all nonischemic liver lobes, more than half of wild-type mice succumbed, whereas all PHD1(-/-) mice survived. Also, short-term inhibition of PHD1 through RNA interference-mediated silencing provided protection against I/R. Knockdown of PHD1 also induced hypoxia tolerance of hepatocytes ''in vitro''. Mechanistically, loss of PHD1 decreased production of oxidative stress, which likely relates to a decrease in oxygen consumption as a result of a reprogramming of hepatocellular metabolism.'''CONCLUSIONS:''' Loss of PHD1 provided tolerance of hepatocytes to acute hypoxia and protected them against I/R-damage. Short-term inhibition of PHD1 is a novel therapeutic approach to reducing or preventing I/R-induced liver injury.ducing or preventing I/R-induced liver injury. +
'''BACKGROUND AND AIMS:'''We investigated … '''BACKGROUND AND AIMS:'''We investigated whether in patients with liver cirrhosis reduced muscle strength is related to dysfunction of muscle mitochondria.'''METHODS:''' The mitochondrial respiratory capacity of the tibial anterior muscle was evaluated in seven patients and eight healthy control subjects by 31P nuclear magnetic resonance spectroscopy (31PMRS) to express ATP turnover in vivo and by respirometry of permeabilized fibres from the same muscle to express the in vitro capacity for oxygen consumption.'''RESULTS:''' Maximal voluntary contraction force for plantar extension was low in the patients (46% of the control value; P < 0.05), but neither the capacity for mitochondrial ATP synthesis, V(max-ATP) (0.38 ± 0.26 vs. 0.50 ± 0.07 mM s(-1) ; P = 0.13) nor the in vitro VO(2max) (0.52 ± 0.21 vs. 0.48 ± 0.21 μmol O2 (min g wet wt.)(-1) P = 0.25) were lowered correspondingly. Also, the activity of citrate synthesis and the respiratory chain complexes II and IV were similar in patients and controls. However during the contractions, the contribution to initial anaerobic ATP production from glycolysis relative to that from PCr was reduced in the patients (0.73 ± 0.22 vs. 0.99 ± 0.09; P < 0.01).'''CONCLUSIONS:''' The results demonstrate that the markedly lower capacity for force generation in patients with liver cirrhosis is unrelated to their capacity for muscle ATP turnover, but the attenuated initial acceleration of anaerobic glycolysis suggests that these patients could be affected by a central limitation to force generation.ted by a central limitation to force generation. +
'''BACKGROUND:''' Mild cold exposure and o … '''BACKGROUND:''' Mild cold exposure and overfeeding are known to elevate energy expenditure in mammals, including humans. This process is called adaptive thermogenesis. In small animals, adaptive thermogenesis is mainly caused by mitochondrial uncoupling in brown adipose tissue and regulated via the sympathetic nervous system. In humans, skeletal muscle is a candidate tissue, known to account for a large part of the epinephrine-induced increase in energy expenditure. However, mitochondrial uncoupling in skeletal muscle has not extensively been studied in relation to adaptive thermogenesis in humans. Therefore we hypothesized that cold-induced adaptive thermogenesis in humans is accompanied by an increase in mitochondrial uncoupling in skeletal muscle.'''METHODOLOGY/PRINCIPAL FINDINGS:''' The metabolic response to mild cold exposure in 11 lean, male subjects was measured in a respiration chamber at baseline and mild cold exposure. Skeletal muscle mitochondrial uncoupling (state 4) was measured in muscle biopsies taken at the end of the respiration chamber stays. Mild cold exposure caused a significant increase in 24h energy expenditure of 2.8% (0.32 MJ/day, range of -0.21 to 1.66 MJ/day, ''p''<0.05). The individual increases in energy expenditure correlated to state 4 respiration (''p''<0.02, ''R''(2) = 0.50).'''CONCLUSIONS/SIGNIFICANCE:''' This study for the first time shows that in humans, skeletal muscle has the intrinsic capacity for cold induced adaptive thermogenesis via mitochondrial uncoupling under physiological conditions. This opens possibilities for mitochondrial uncoupling as an alternative therapeutic target in the treatment of obesity. therapeutic target in the treatment of obesity. +
'''BEC tutorial-Living Communications. Fro … '''BEC tutorial-Living Communications. From Peter Mitchell’s protonmotive force to protonmotive pressure: elements of the science of bioenergetics. Preceding the '''[[MiPNet27.04 IOC155 Schroecken AT |Oroboros O2k-Workshop on high-resolution respirometry]]'''. Schroecken, Austria; 2022.[[File:Gnaiger 2020 BEC MitoPathways.jpg|left|100px|link=Gnaiger_2020_BEC_MitoPathways|Gnaiger 2020 BEC MitoPathways]]The [[mitochondrial membrane potential]] is an element of the science of bioenergetics, linked to the control of respiratory flux and related mitochondrial functions. A [https://pubmed.ncbi.nlm.nih.gov/?term=mitochondrial+membrane+potential PubMed search] on ‘mitochondrial membrane potential’ yields 40 000 results and 3452 for 2021 (search 2022-09-20), with a linear increase during the past 20 years. [[Gnaiger_2020_BEC_MitoPathways#Chapter_8._Protonmotive_pressure_and_respiratory_control |Chapter 8]] on ‘Protonmotive pressure and respiratory control’ of [[Mitochondrial Pathways]] (Gnaiger 2020) introduces a novel perspective on Peter Mitchell’s protonmotive force, which incorporates the mitochondrial membrane potential. If you find the reading is tough, you are not alone. Join this BEC tutorial-Living Communications for a fundamental introduction into the relevant concepts of physical chemistry, which differ from [[Force#Thermodynamic_ignorance |misleading chapters in bioenergetics textbooks]]. A retreat with plenty of informal discussions and group interactions takes you on a journey to visit chemical potential differences versus potential gradients, Gibbs [[energy]] versus Gibbs [[force]], quantities of capacity versus intensity, protonmotive force and [[motive unit]]s, [[flow]]s and [[force]]s, and finally protonmotive [[pressure]]. This will introduce students (and teachers) to a new understanding of mitochondrial membrane potential and the protonmotive force, connecting the ideal gas equation, osmotic pressure, the [[Boltzmann constant]] and [[gas constant]] with [[Fick 1855 Pogg Ann |Fick’s]] and [[Einstein 1905 Ann Physik 549 |Einstein’s diffusion equation]]. If theory gets dry and grey, join for a swim in lake Körbersee, for a Walk&Talk in the colorful alpine environment of the Schröcken-Tannberg region, and a visit to the [https://www.alpmuseum.at/ Alpmuseum ufm Tannberg].s://www.alpmuseum.at/ Alpmuseum ufm Tannberg]. +
'''BEC tutorial-Living Communications. Mit … '''BEC tutorial-Living Communications. Mitochondrial membrane potential and Peter Mitchell’s protonmotive force: elements of the science of bioenergetics. Preceding the [[EMC2022 Prague CZ |EMC 2022 49th European Muscle Conference]], Prague, Czech Republic.[[File:Gnaiger 2020 BEC MitoPathways.jpg|left|100px|link=Gnaiger_2020_BEC_MitoPathways|Gnaiger 2020 BEC MitoPathways]]The [[mitochondrial membrane potential]] is an element of the science of bioenergetics, linked to the control of respiratory flux and related mitochondrial functions. A [https://pubmed.ncbi.nlm.nih.gov/?term=mitochondrial+membrane+potential PubMed search] on ‘mitochondrial membrane potential’ yields 40 000 results and 3452 for 2021 (search 2022-09-20), with a linear increase during the past 20 years. [[Gnaiger_2020_BEC_MitoPathways#Chapter_8._Protonmotive_pressure_and_respiratory_control |Chapter 8]] on ‘Protonmotive pressure and respiratory control’ of [[Mitochondrial Pathways]] (Gnaiger 2020) introduces a novel perspective on Peter Mitchell’s protonmotive force, which incorporates the mitochondrial membrane potential. If you find the reading is tough, you are not alone. Join this BEC tutorial-Living Communications for an introduction into the relevant concepts of physical chemistry, which differ from [[Force#Thermodynamic_ignorance |misleading chapters in bioenergetics textbooks]] on potential gradients, Gibbs ''[[energy]]'', protonmotive [[flow]] and [[force]], and finally protonmotive [[pressure]]. This will introduce students (and teachers) to a new understanding of mitochondrial membrane potential and the protonmotive force, connecting the ideal gas equation, osmotic pressure, the [[Boltzmann constant]] and [[gas constant]] with [[Fick 1855 Pogg Ann |Fick’s]] and [[Einstein 1905 Ann Physik 549 |Einstein’s diffusion equation]]. If theory gets tough, join for a [[MiPNet27.05 BEC tutorial-Living Communications pmF |follow-up retreat]].C tutorial-Living Communications pmF |follow-up retreat]]. +
'''BEC tutorial-Living Communications. Mit … '''BEC tutorial-Living Communications. Mitochondrial membrane potential and Peter Mitchell’s protonmotive force: elements of the science of bioenergetics. [[File:Gnaiger 2020 BEC MitoPathways.jpg|left|100px|link=Gnaiger_2020_BEC_MitoPathways|Gnaiger 2020 BEC MitoPathways]]The [[mitochondrial membrane potential]] is an element of the science of bioenergetics, linked to the control of respiratory flux and related mitochondrial functions. A PubMed search on ‘mitochondrial membrane potential’ yields nearly 40 000 results and 3442 for 2021 (search 2022-07-04), with a linear increase during the past 20 years. [[Gnaiger_2020_BEC_MitoPathways#Chapter_8._Protonmotive_pressure_and_respiratory_control |Chapter 8]] on ‘Protonmotive pressure and respiratory control’ of [[Mitochondrial Pathways]] (Gnaiger 2020) introduces a novel perspective on Peter Mitchell’s protonmotive force, which incorporates the mitochondrial membrane potential. If you find the reading is tough, you are not alone. Join this BEC tutorial-Living Communications for an introduction into the relevant concepts of physical chemistry, which differ from [[Force#Thermodynamic_ignorance |misleading chapters in bioenergetics textbooks]] on potential gradients, Gibbs ''[[energy]]'', protonmotive [[flow]] and [[force]], and finally protonmotive [[pressure]]. This will introduce students (and teachers) to a new understanding of mitochondrial membrane potential and the protonmotive force, connecting the ideal gas equation, osmotic pressure, the [[Boltzmann constant]] and [[gas constant]] with [[Fick 1855 Pogg Ann |Fick’s]] and [[Einstein 1905 Ann Physik 549 |Einstein’s diffusion equation]]. If theory gets tough, join for a [[MiPNet27.05 BEC tutorial-Living Communications pmF |follow-up retreat]].C tutorial-Living Communications pmF |follow-up retreat]]. +
'''Background ''' Mitochondrial dysfuncti … '''Background ''' Mitochondrial dysfunction is one of the most characteristic properties of the cancer cell. However, it is not known whether oxidative energy metabolism has already become altered in conditions of atrophic gastritis, a precancerous state of gastric disease. The purpose of our study was to comparatively characterize oxidative phosphorylation (OXPHOS) in the atrophic and nonatrophic gastric corpus mucosa.'''Methods''' Mucosal biopsies were taken from 12 patients with corpus dominant atrophic gastritis and from 12 patients with nonatrophic mucosa (controls). One part of the tissue samples was permeabilized with saponin for analysis of the function of the respiratory chain using high-resolution respirometry, and another part was used for histopathological examination. The serum level of pepsinogen I (S-PGI) was determined with a specific enzyme immunoassay (EIA).'''Results''' Compared to the control group, the maximal capacity of OXPHOS in the atrophy group was almost twofold lower, the respiratory chain complex I-dependent respiration, normalized to complex II-dependent respiration, was reduced, and respiratory control by ADP in the presence of succinate was increased in the atrophic corpus mucosa. In the whole cohort of the patients studied, serum S-PGI level correlated positively with complex I-dependent respiration or complex Idependent to complex II-dependent respiration ratio.'''Conclusions''' Corpus dominant atrophic gastritis is characterized by decreased respiratory capacity and relative deficiency of the respiratory complex I of mitochondria in the mucosa, the latter defect probably limiting mitochondrial ATP production and energetic support of the secretory function of the zymogenic mucosal cells.y function of the zymogenic mucosal cells. +
'''Background''' Mitochondrial dysfunction … '''Background''' Mitochondrial dysfunction and degradation takes a central role in current paradigms of neurodegeneration in Parkinson's disease (PD). Loss of DJ-1 function is a rare cause of familial PD. Although a critical role of DJ-1 in oxidative stress response and mitochondrial function has been recognized, the effects on mitochondrial dynamics and downstream consequences remain to be determined.'''Methodology/Principal Findings''' Using DJ-1 loss of function cellular models from knockout (KO) mice and human carriers of the E64D mutation in the DJ-1 gene we define a novel role of DJ-1 in the integrity of both cellular organelles, mitochondria and lysosomes. We show that loss of DJ-1 caused impaired mitochondrial respiration, increased intramitochondrial reactive oxygen species, reduced mitochondrial membrane potential and characteristic alterations of mitochondrial shape as shown by quantitative morphology. Importantly, ultrastructural imaging and subsequent detailed lysosomal activity analyses revealed reduced basal autophagic degradation and the accumulation of defective mitochondria in DJ-1 KO cells, that was linked with decreased levels of phospho-activated ERK2.'''Conclusions/Significance''' We show that loss of DJ-1 leads to impaired autophagy and accumulation of dysfunctional mitochondria that under physiological conditions would be compensated via lysosomal clearance. Our study provides evidence for a critical role of DJ-1 in mitochondrial homeostasis by connecting basal autophagy and mitochondrial integrity in Parkinson's disease.hondrial integrity in Parkinson's disease. +
'''Background''': "Open peer review" (OPR) … '''Background''': "Open peer review" (OPR), despite being a major pillar of Open Science, has neither a standardized definition nor an agreed schema of its features and implementations. The literature reflects this, with numerous overlapping and contradictory definitions. While for some the term refers to peer review where the identities of both author and reviewer are disclosed to each other, for others it signifies systems where reviewer reports are published alongside articles. For others it signifies both of these conditions, and for yet others it describes systems where not only "invited experts" are able to comment. For still others, it includes a variety of combinations of these and other novel methods. '''Methods''': Recognising the absence of a consensus view on what open peer review is, this article undertakes a systematic review of definitions of "open peer review" or "open review", to create a corpus of 122 definitions. These definitions are systematically analysed to build a coherent typology of the various innovations in peer review signified by the term, and hence provide the precise technical definition currently lacking. '''Results''': This quantifiable data yields rich information on the range and extent of differing definitions over time and by broad subject area. Quantifying definitions in this way allows us to accurately portray exactly how ambiguously the phrase "open peer review" has been used thus far, for the literature offers 22 distinct configurations of seven traits, effectively meaning that there are 22 different definitions of OPR in the literature reviewed. '''Conclusions''': I propose a pragmatic definition of open peer review as an umbrella term for a number of overlapping ways that peer review models can be adapted in line with the aims of Open Science, including making reviewer and author identities open, publishing review reports and enabling greater participation in the peer review process. participation in the peer review process. +
'''Background''': Atherosclerosis is one o … '''Background''': Atherosclerosis is one of the major complications of diabetes, which may result from insulin resistance via mitochondrial dysfunction. Although a strong association between insulin resistance and cardiovascular disease has been suggested, it is not clear yet whether stress-inducing factors damage mitochondria and insulin signaling pathway in cardiovascular tissues.'''Methods''': We investigated whether stress-induced mitochondrial dysfunction might alter the insulin/Akt signaling pathway in A10 rat vascular smooth muscle cells (VSMC).'''Results''': The treatment of oxidized low density lipoprotein (oxLDL) decreased ATP contents, mitochondrial respiration activity, mRNA expressions of OXPHOS subunits and IRS-1/2 and insulin-mediated phosphorylations of Akt and AMP-activated protein kinase (AMPK). Similarly, dideoxycytidine (ddC), the mtDNA replication inhibitor, or rotenone, OXPHOS complex I inhibitor, inhibited the insulin-mediated pAkt while increased pAMPK regardless of insulin. Reciprocally, an inhibitor of Akt, triciribine (TCN), decreased cellular ATP contents. Overexpression of Akt dominant positive reversed the oxLDL- or ddC-mediated ATP decrease but AMPK activator did not. Akt activation also normalized the aberrant VSMC migration induced by ddC.'''Conclusions''': Defective insulin signaling and mitochondrial function may collectively contribute to developing cardiovascular disease.'''General significance''': Akt may be a possible therapeutic target for treating insulin resistance-associated atherosclerosis.lin resistance-associated atherosclerosis. +
'''Background''': It has been hypothesized … '''Background''': It has been hypothesized that reduced axonal transport contributes to the degeneration of neuronal processes in Parkinson's disease (PD). Mitochondria supply the adenosine triphosphate (ATP) needed to support axonal transport and contribute to many other cellular functions essential for the survival of neuronal cells. Furthermore, mitochondria in PD tissues are metabolically and functionally compromised. To address this hypothesis, we measured the velocity of mitochondrial movement in human transmitochondrial cybrid "cytoplasmic hybrid" neuronal cells bearing mitochondrial DNA from patients with sporadic PD and disease-free age-matched volunteer controls (CNT). The absorption of low level, near-infrared laser light by components of the mitochondrial electron transport chain (mtETC) enhancesmitochondrial metabolism, stimulates oxidative phosphorylation and improves redox capacity. PD and CNT cybrid neuronal cells were exposed to near-infrared laser light to determine if the velocity of mitochondrial movement can be restored by low level light therapy (LLLT). Axonal transport of labeled mitochondria was documented by time lapse microscopy in dopaminergic PD and CNT cybrid neuronal cells before and after illumination with an 810 nm diode laser (50 mW/cm2) for 40 s. Oxygen utilization and assembly of mtETS complexes were also determined.'''Results''': The velocity of mitochondrial movement in PD cybrid neuronal cells (0.175 +/- 0.005 SEM) was significantly reduced (p < 0.02) compared to mitochondrial movement in disease free CNT cybrid neuronal cells (0.232 +/- 0.017 SEM). For two hours after LLLT, the average velocity of mitochondrial movement in PD cybrid neurites was significantly (p < 0.003) increased (to 0.224 +/- 0.02 SEM) and restored to levels comparable to CNT. Mitochondrial movement in CNT cybrid neurites was unaltered by LLLT (0.232 +/- 0.017 SEM). Assembly of complexes in the mtETC was reduced and oxygen utilization was altered in PD cybrid neuronal cells. PD cybrid neuronal cell lines with the most dysfunctional mtETC assembly and oxygen utilization profiles were least responsive to LLLT.'''Conclusion''': The results from this study support our proposal that axonal transport is reduced in sporadic PD and that a single, brief treatment with near-infrared light can restore axonal transport to control levels. These results are the first demonstration that LLLT can increase axonal transport in model human dopaminergic neuronal cells and they suggest that LLLT could be developed as a novel treatmentto improve neuronal function in patients with PD. treatment to improve neuronal function in patients with PD. +
'''Background''': Reactive oxygen species … '''Background''': Reactive oxygen species (ROS) are among the main determinants of cellular damage during ischemia and reperfusion. There is also ample evidence that mitochondrial ROS production is involved in signaling during ischemic and pharmacological preconditioning. In a previous study we analyzed the mitochondrial effects of the efficient preconditioning drug diazoxide and found that it increased the mitochondrial oxidation of the ROS-sensitive fluorescent dye 2′,7′-dichlorodihydrofluorescein (H2DCF) but had no direct impact on the H2O2 production of submitochondrial particles (SMP) or intact rat heart mitochondria (RHM).'''Methods''': H2O2 generation of bovine SMP and tightly coupled RHM was monitored under different conditions using the amplex red/horseradish peroxidase assay in response to diazoxide and a number of inhibitors.'''Results''': We show that diazoxide reduces ROS production by mitochondrial Complex I under conditions of reverse electron transfer in tightly coupled RHM, but stimulates mitochondrial ROS production at the Qo site of Complex III under conditions of oxidant-induced reduction; this stimulation is greatly enhanced by uncoupling. These opposing effects can both be explained by inhibition of Complex II by diazoxide. 5-Hydroxydecanoate had no effect, and the results were essentially identical in the presence of Na+ or K+ excluding a role for putative mitochondrial KATP-channels.'''General significance''': A straightforward rationale is presented to mechanistically explain the ambivalent effects of diazoxide reported in the literature. Depending on the metabolic state and the membrane potential of mitochondria, diazoxide-mediated inhibition of Complex II promotes transient generation of signaling ROS at Complex III (during preconditioning) or attenuates the production of deleterious ROS at Complex I (during ischemia and reperfusion).x III (during preconditioning) or attenuates the production of deleterious ROS at Complex I (during ischemia and reperfusion). +
'''Background''': Restriction of intracell … '''Background''': Restriction of intracellular diffusion of adenine nucleotides has been studied intensively on adult rat cardiomyocytes. However, their cause and role ''in vivo'' is still uncertain. Intracellular membrane structures have been suggested to play a role. We therefore chose to study cardiomyocytes from rainbow trout (''Oncorhynchus mykiss''), which are thinner and have fewer intracellular membrane structures than adult rat cardiomyocytes. Previous studies suggest that trout permeabilized cardiac fibers also have diffusion restrictions. However, results from fibers may be affected by incomplete separation of the cells. This is avoided when studying permeabilized, isolated cardiomyocytes. The aim of this study was to verify the existence of diffusion restrictions in trout cardiomyocytes by comparing ADP-kinetics of mitochondrial respiration in permeabilized fibers, permeabilized cardiomyocytes and isolated mitochondria from rainbow trout heart. Experiments were performed at 10, 15 and 20°C in the absence and presence of creatine.'''Results''': Trout cardiomyocytes hypercontracted in the solutions used for mammalian cardiomyocytes. We developed a new solution in which they retained their shape and showed stable steady state respiration rates throughout an experiment. The apparent ADP-affinity of permeabilized cardiomyocytes was different from that of fibers. It was higher, independent of temperature and not increased by creatine. However, it was still about ten times lower than in isolated mitochondria.'''Conclusions''': The differences between fibers and cardiomyocytes suggest that results from trout heart fibers were affected by incomplete separation of the cells. However, the lower ADP-affinity of cardiomyocytes compared to isolated mitochondria indicate that intracellular diffusion restrictions are still present in trout cardiomyocytes despite their lower density of intracellular membrane structures. The lack of a creatine effect indicates that trout heart lacks mitochondrial creatine kinase tightly coupled to respiration. This argues against diffusion restriction by the outer mitochondrial membrane. These results from rainbow trout cardiomyocytes resemble those from other low-performance hearts such as neonatal rat and rabbit hearts. Thus, it seems that metabolic regulation is related to cardiac performance, and it is likely that rainbow trout can be used as a model animal for further studies of the localization and role of diffusion restrictions in lowperformance hearts.ion restrictions in lowperformance hearts. +
'''Background''': Tumor cells are characte … '''Background''': Tumor cells are characterized by accelerated growth usually accompanied by up-regulated pathways that ultimately increase the rate of ATP production. These cells can suffer metabolic reprogramming, resulting in distinct bioenergetic phenotypes, generally enhancing glycolysis channeled to lactate production. In the present work we showed metabolic reprogramming by means of inhibitors of histone deacetylase (HDACis), sodium butyrate and trichostatin. This treatment was able to shift energy metabolism by activating mitochondrial systems such as the respiratory chain and oxidative phosphorylation that were largely repressed in the untreated controls.'''Methodology/Principal Findings''': Various cellular and biochemical parameters were evaluated in lung cancer H460 cells treated with the histone deacetylase inhibitors (HDACis), sodium butyrate (NaB) and trichostatin A (TSA). NaB and TSA reduced glycolytic flux, assayed by lactate release by H460 cells in a concentration dependent manner. NaB inhibited the expression of glucose transporter type 1 (GLUT 1), but substantially increased mitochondria bound hexokinase (HK) activity. NaB induced increase in HK activity was associated to isoform HK I and was accompanied by 1.5 fold increase in HK I mRNA expression and cognate protein biosynthesis. Lactate dehydrogenase (LDH) and pyruvate kinase (PYK) activities were unchanged by HDACis suggesting that the increase in the HK activity was not coupled to glycolytic flux. High resolution respirometry of H460 cells revealed NaB-dependent increased rates of oxygen consumption coupled to ATP synthesis. Metabolomic analysis showed thatNaB altered the glycolytic metabolite profile of intact H460 cells. Concomitantly we detected an activation of the pentose phosphate pathway (PPP). The high O2 consumption in NaB-treated cells was shown to be unrelated to mitochondrial biogenesis since citrate synthase (CS) activity and the amount of mitochondrial DNA remained unchanged.'''Conclusion''': NaB and TSA induced an increase in mitochondrial function and oxidative metabolism in H460 lung tumor cells concomitant with a less proliferative cellular phenotype.h a less proliferative cellular phenotype. +
'''Background'''—Opening of the mitochondr … '''Background'''—Opening of the mitochondrial permeability transition pore (mPTP) is a crucial event in lethal reperfusion injury. Phosphorylation (inhibition) of glycogen synthase kinase-3β (GSK3β) has been involved in cardioprotection. We investigated whether phosphorylated GSK3β may protect the heart via the inhibition of mPTP opening during postconditioning.'''Methods and Results'''—Wild-type and transgenic GSK3β-S9A mice (the cardiac GSK3β activity of which cannot be inactivated) underwent 60 minutes of ischemia and 24 hours of reperfusion. At reperfusion, wild-type and GSK3β-S9A mice received no intervention (control), postconditioning (3 cycles of 1 minute ischemia and 1 minute of reperfusion), the mPTP inhibitor cyclosporine A (CsA; 10 mg/kg IV), or the GSK3β inhibitor SB216763 (SB21; 70 µg/kg IV). Infarct size was assessed by triphenyltetrazolium chloride staining. The resistance of the mPTP to opening after Ca2+ loading was assessed by spectrofluorometry on mitochondria isolated from the area at risk. In wild-type mice, infarct size was significantly reduced by postconditioning, CsA, and SB21, averaging 39±2%, 35±5%, and 37±4%, respectively, versus 58±5% of the area at risk in control mice (P<0.05). In GSK3β-S9A mice, only CsA, but not postconditioning or SB21, reduced infarct size. Postconditioning, CsA, and SB21 all improved the resistance of the mPTP in wild-type mice, but only CsA did so in GSK3β-S9A mice.'''Conclusion'''—These results suggest that S9-phosphorylation of GSK3β is required for postconditioning and likely acts by inhibiting the opening of the mitochondrial permeability transition pore.pening of the mitochondrial permeability transition pore. +
'''Background:''' Appropriate control of m … '''Background:''' Appropriate control of mitochondrial function, morphology and biogenesis are crucial determinants of the general health of eukaryotic cells. It is therefore imperative that we understand the mechanisms that coordinatemitochondrial function with environmental signaling systems. The regulation of yeast mitochondrial function in response to nutritional change can be modulated by PKA activity. Unregulated PKA activity can lead to the production of mitochondria that are prone to the production of ROS, and an apoptotic form of cell death.'''Results:''' We present evidence that mitochondria are sensitive to the level of cAMP/PKA signaling and can respond by modulating levels of respiratory activity or committing to self execution. The inappropriate activation of one ofthe yeast PKA catalytic subunits, Tpk3p, is sufficient to commit cells to an apoptotic death through transcriptional changes that promote the production of dysfunctional, ROS producing mitochondria. Our data implies that cAMP/PKA regulation of mitochondrial function that promotes apoptosis engages the function of multiple transcription factors, including HAP4, SOK2 and SCO1.'''Conclusions:''' We propose that in yeast, as is the case in mammalian cells, mitochondrial function and biogenesis are controlled in response to environmental change by the concerted regulation of multiple transcription factors. The visualization of cAMP/TPK3 induced cell death within yeast colonies supports a model that PKA regulation plays a physiological role in coordinating respiratory function and cell death with nutritional status in budding yeast. with nutritional status in budding yeast. +
'''Background:''' Determination of mitocho … '''Background:''' Determination of mitochondrial membrane potential ((m) is widely used to characterize cellular metabolism, viability, and apoptosis. Changes of ΔΨm induced by inhibitors of oxidative phosphorylation characterizerespective contributions of mitochondria and glycolysis to adenosine triphosphate (ATP) synthesis.'''Methods:''' ΔΨm in BSC-40 and HeLa G cell lines was determined by flow cytometry and spectrofluorometry. Its changes induced by specific mitochondrial inhibitors were evaluated using 3,3 ΔΨ-dihexyloxacarbocyanine iodide(DiOC6(3)), tetramethylrhodamine ethyl ester, and Mito-Tracker Red. Mitochondrial function was further characterized by oxygen consumption.'''Results:''' Inhibition of respiration by antimycin A or uncouplingof mitochondria by FCCP decreased ΔΨm in both cell lines. Inhibition of ATP production by oligomycin or atractyloside induced a moderate decrease of ΔΨmin HeLa G cells and an increase of ΔΨm in BSC-40 cells. Statistically significant differences in ΔΨm between the two cell lines were found with both flow cytometry and spectrofluorometry. Respirometry showed higher basaland FCCP-stimulated respiration in BSC-40 cells.'''Conclusion:''' Changes of ΔΨm and oxygen consumption showed that BSC-40 cells are more sensitive than HeLa G cells to inhibitors of mitochondrial function, suggesting that BSC-40 cells are more dependent than HeLa G cells onaerobic ATP production. Determination of ΔΨm changes by flow cytometry exhibited greater sensitivity than the ones by spectrofluorometry.ivity than the ones by spectrofluorometry. +
'''Background:''' Sepsis is a severe infla … '''Background:''' Sepsis is a severe inflammatory disorder with a high mortality in intensive care units mostly due to multiorgan failure. Mitochondrial dysfunction is regarded as a key factor involved in the pathogenesis of septic disorders, leading to a decline in energy supply. The aim of the present study was to evaluate whether application of short-chain fatty acids (SCFAs) and medium-chain fatty acids (MCFAs) could improve mitochondrial function and thus might serve as a potential energy source under inflammatory conditions. '''Materials and Methods:''' As an experimental approach, starved human endothelial cells and monocytes were incubated with hexanoic acid, heptanoic acid, octanoic acid, or glucose and subsequently subjected to high-resolution respirometry to assess mitochondrial function under baseline conditions. In a second set of experiments, cells were pretreated with tumor necrosis factor-α to mimic inflammation and sepsis. Results: We demonstrated that addition of SCFAs and MCFAs increases mitochondrial respiratory capacity at baseline and inflammatory conditions in both cell types. None of the fatty acids induced changes in mitochondrial DNA content or the generation of proinflammatory cytokines, indicating a beneficial safety profile. '''Conclusion:''' We deduce that SCFAs and MCFAs are suitable and safe sources of energy under inflammatory conditions with the capability to partly restore mitochondrial respiration. partly restore mitochondrial respiration. +
'''Basal respiration''' is well defined in physiology. Terminology in mitochondrial physiology gains quality by reference to established concepts. +
'''Bioblast 2022: Inaugural Conference of ''Bioenergetics Communications''''' +
'''Bioblast''' was launched as a glossary … '''Bioblast''' was launched as a glossary and index for high-resolution respirometry (Oroboros Instruments: OroboPedia) and Mitochondrial Physiology (MitoPedia), to find topics quickly, as a dynamic tool for summarizing definitions of terms, symbols and abbreviations. However, it´s potential benefits as an innovative, self-developing database make the '''Bioblast Wiki''' much more than a service by Oroboros.i''' much more than a service by Oroboros. +
'''COST CA22169 METAHEART Kick-off meeting MC1, Brussels, Belguim, 2023-10-18''' +
'''Call for research - We all need oxygen … '''Call for research - We all need oxygen – “The oceans are gasping for air”''' 1, 2, 3“Human dominion over planet Earth is driving profound changes that may culminate in extinction.” 4 Whilst there is wider research into the oceanic impact of climate change including warming and acidification,5, 6 and on oxygen content of oceans, there is very little research into the specific impact of acidification and related carbon dioxide changes on marine photosynthetic oxygen production.This is an important field of research as it also involves consideration of the consequent effects of excess atmospheric carbon dioxide, including warming, on oceanic and atmospheric oxygen, oxygen exchange between them and possibilities of tipping points whereby photosynthetic marine organisms may rapidly die off, potentially leading to severe existential consequences for aerobic life forms.We bemoan the loss of polar bears and rare alpine plants along with changes to weather and food, but as societies and individuals we are reluctant to severely moderate the day-to-day fossil fuel energy consumption that underlies 21st century life. When faced by the choice of polar bears vs cars, heating, laptops and phones, the polar bears lose!Ocean acidification is a more empirically evidenced phenomenon than climate change, however, it is also less prominent in the public psyche even though it springs from the same increased atmospheric carbon dioxide levels. Were research to be commissioned, though, that provides clear evidence of risk to oceanic oxygen production and therefore atmospheric oxygen levels, the conclusions could be far-reaching, including identifying a potential tipping point that may result in human extinction.This stark prospect would, arguably, be easier to convey to, and fix in the wider public consciousness than the more diffuse issues around climate change. Humans are reminded with every breath they take that oxygen is essential to their health function and, ultimately, their survival and existence as a species.7 The importance of the prospect of oxygen depletion for future generations would be easily understood by all, and so promote greater public engagement and cohesive demand for a global response to try and find viable energy alternatives to fossil fuels.iable energy alternatives to fossil fuels. +
'''Chemical biology approaches to assessing and modulating mitochondria, Buckinghamshire, UK''' +
'''Contents''' * Introduction [http://www. … '''Contents'''* Introduction [http://www.oroboros.at/fileadmin/user_upload/Reprints/O-MiPNet-Publ/MitoPathways2_Introduction.pdf pdf]* MitoPathways to Complex I: [[MiPNet11.04]]* MitoPathways to Complex II: [[MiPNet11.09]]* MitoPathways to Complexes I&II: [[MiPNet12.12]]* MitoPathways compilation: [[MiPNet12.13]] * MitoPathways - respiratory states: [[MiPNet12.15]]* Cell respiration and phosphorylation control: [[MiPNet08.09]] * HRR and phosphorylation control: [[MiPNet10.04]]* FCRs in isolated mitochondria: [[MiPNet12.11]]* O2k manual titrations: [[MiPNet09.12]]* O2k-paradigm: [[MiPNet09.01]]* [[Gnaiger 2012 MitoPathways References|References]]* The Oroboros - Feeding on negative entropy [http://www.oroboros.at/fileadmin/user_upload/Reprints/O-MiPNet-Publ/MitoPathways2_Introduction.pdf pdf]Reprints/O-MiPNet-Publ/MitoPathways2_Introduction.pdf pdf] +
'''Context''': Previous studies on leg ske … '''Context''': Previous studies on leg skeletal musculature have demonstrated mitochondrial dysfunction associated with type 2 diabetes mellitus (T2DM), but it is not known whether mitochondrial dysfunction is present in the upper extremities.'''Objective''': The aim of the study was to compare mitochondrial respiration and markers of mitochondrial content in skeletal muscle of arm and leg in patients with T2DM and obese control subjects.'''Patients''': Ten patients with T2DM (age, 52.3 ± 2.7 yr; body mass index, 30.1 ± 1.2 kg/m2) (mean ± SE) were studied after a 2-wk washout period of oral antihyperglycemic agents. Ten control subjects (age, 54.3 ± 2.8 yr; body mass index, 30.4 ± 1.2 kg/m2) with normal fasting and 2-h oral glucosetolerance test blood glucose levels were also included. Main Outcome Measure:Wemeasured mitochondrial respiration in saponin-treated skinned musclefibers from biopsies of m. deltoideus and m. vastus lateralis using high-resolution respirometry.'''Results''': In the arm, mitochondrial respiration and citrate synthase activity did not differ between groups, but mitochondrial respiration per milligram of muscle was significantly higher in the leg muscle of the control subjects compared to T2DM. Fiber type compositions in arm and leg muscleswere not different between the T2DM and control group, and maximum rate of O2 consumption did not differ between the groups.'''Conclusion''': The results demonstrate that reduced mitochondrial function in T2DM is only present in the leg musculature. This novel finding suggests that mitochondrial dysfunction is not a primary defect affecting all skeletal muscle but could be related to a decreased response to locomotor muscle use in T2DM. (J Clin Endocrinol Metab 95: 857–863, 2010)J Clin Endocrinol Metab 95: 857–863, 2010) +
'''Do you ever dream about an equation?'' … '''Do you ever dream about an equation?''The Mitchell’s dream series by [[Odra Noel]] is a dream on equations and shows a dream on the equation that penetrates all of biology since Peter D Mitchell started publishing on the protonmotive force equation [1]. Can we imagine how many dreaming was required until the chemiosmotic hypothesis emerged on energy coupling by the protonmotive force of oxidative phosphorylation in the bioblasts, which comprise the mitochondria, chloroplasts, bacteria and archaea? Seeing Odra Noel’s pictures on Mitchell’s dream provides insights into the equations of biophysics and biochemistry: these equations do not just belong to our books. They do belong to our cells, our [[bioblasts]], to the living world. It is the mitochondria that help us to understand these equations, since the equations are in the mitochondria, they are the visible parts of the mitochondria and open insights into function beyond the visible form – this is mitochondrial physiology.e form – this is mitochondrial physiology. +
'''Doerrier C, Draxl A, Wiethuechter A, Ei … '''Doerrier C, Draxl A, Wiethuechter A, Eigentler A, Gnaiger E (2015) Mitochondrial respiration in permeabilized fibers versus homogenate from fish liver and heart. An application study with the PBI-Shredder. Mitochondr Physiol Network 17.03(04):1-9.''' In the present study we compared mitochondrial function of permeabilized fibers and homogenate of heart muscle of mice. In addition, respiration of trout heart homogenate preparations were compared with permeabilized fibers, and the PBI-Shredder was successfully tested with preparation of trout liver.:» Product: [[Oroboros O2k]], [[OROBOROS O2k-Catalogue | O2k-Catalogue]][OROBOROS O2k-Catalogue | O2k-Catalogue]] +
'''Doerrier C, Gnaiger E (2003-2016) High- … '''Doerrier C, Gnaiger E (2003-2016) High-resolution respirometry and coupling-control protocol with living cells: ROUTINE, LEAK, ET-pathway, ROX. Mitochondr Physiol Network 08.09(11):1-8.'''An experiment on respiration of [[living cells]] is reported from an O2k-Workshop on high-resolution respirometry. Leukemia cells were incubated at a density of 1 million cells/ml in 2 ml culture medium in two O2k-Chambers operated in parallel. Cellular ROUTINE respiration, ''J''R, resulted in volume-specific oxygen consumption of 20 pmol·s-1·ml-1. Oxygen concentration changed by merely 6.4 and 6.5 µM in the two O2k-Chambers over a period of 5 min (<1% air saturation per minute). Inhibition by oligomycin (''JL''), and rotenone (residual oxygen consumption, ''J''ROX; after uncoupling) reduced respiration to 5 and 1 pmol·s-1·ml-1, while inducing the noncoupled state by the uncoupler FCCP revealed the capacity of the Electron transfer-pathway (ET-pathway) at ''JE'' of 50 pmol·s-1·ml-1. The ROUTINE control ratio, ''R/E'', was 0.4 (uncoupling control ratio, UCR=''E/R''=2.5), and the LEAK control ratio, ''L/E'', was 0.1 (''E/L''=12.0). This indicates tight coupling of OXPHOS, and a large ET-pathway excess capacity over ROUTINE respiration. The net ROUTINE control ratio, net''R''=(''R-L'')/''E'' was 0.30, indicating that 30% of ET-pathway capacity was activated for ATP production.Automatic correction for instrumental background amounted to 13% for ROUTINE respiration, but to >50% and 180% for ''JL'' and ''J''ROX, respectively, illustrating the importance of real-time correction. The experiment illustrates the sensitivity and resproducibility of high-resolution respirometry with the OROBOROS O2k. Calibrations and routine corrections provide the basis of the high accuracy required for mitochondrial respiratory physiology. Real-time analyses were performed, combining high-resolution with instant diagnostic information. In this update graphs are presented illustrating some features of DatLab.:» Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]]os O2k-Catalogue | O2k-Catalogue]] +
'''EBEC2024 Satellite Oroboros O2k-Workshop: Mito&Chlora High-Resolution Respirometry and PhotoBiology'''. Innsbruck, Austria (2024 Sep 02-04). +
'''ET-pathway states''' are defined in [[mitochondrial preparations]] complementary to [[coupling-control state]]s in mitochondrial physiology. +
'''Essentials:''' The role of protein C (P … '''Essentials:''' The role of protein C (PC) activation in experimental autoimmune encephalitis (EAE) is unknown. PC activation is required for mitochondrial function in the central nervous system. Impaired PC activation aggravates EAE, which can be compensated for by soluble thrombomodulin. Protection of myelin by activated PC or solulin is partially independent of immune-modulation.'''SUMMARY:''' Studies with human samples and in rodents established a function of coagulation proteases in neuro-inflammatory demyelinating diseases (e.g. in multiple sclerosis [MS] and experimental autoimmune encephalitis [EAE]). Surprisingly, approaches to increase activated protein C (aPC) plasma levels as well as antibody-mediated inhibition of PC/aPC ameliorated EAE in mice. Hence, the role of aPC generation in demyelinating diseases and potential mechanisms involved remain controversial. Furthermore, it is not known whether loss of aPC has pathological consequences at baseline (e.g. in the absence of disease). To explore the role of thrombomodulin (TM)-dependent aPC generation at baseline and in immunological and non-immunological demyelinating disease models. Myelination and reactive oxygen species (ROS) generation were evaluated in mice with genetically reduced TM-mediated protein C activation (TMPro/Pro) and in wild-type (WT) mice under control conditions or following induction of EAE. Non-immunological demyelination was analyzed in the cuprizone-diet model. Impaired TM-dependent aPC generation already disturbs myelination and mitochondrial function at baseline. This basal phenotype is linked with increased mitochondrial ROS and aggravates EAE. Reducing mitochondrial ROS (p66Shc deficiency), restoring aPC plasma levels or injecting soluble TM (solulin) ameliorates EAE in TMPro/Pro mice. Soluble TM additionally conveyed protection in WT-EAE mice. Furthermore, soluble TM dampened demyelination in the cuprizone-diet model, demonstrating that its myelin-protective effect is partially independent of an immune-driven process. These results uncover a novel physiological function of TM-dependent aPC generation within the CNS. Loss of TM-dependent aPC generation causes a neurological defect in healthy mice and aggravates EAE, which can be therapeutically corrected.© 2016 International Society on Thrombosis and Haemostasis.ically corrected. © 2016 International Society on Thrombosis and Haemostasis. +
'''Expert/inn/en-Workshop Medizintechnik, … '''Expert/inn/en-Workshop Medizintechnik, Innsbruck, AT.'''== Time and Location ==13:00 until 17:00 at Standortagentur Tirol, Ing.-Etzelstr. 17, Innsbruck == General information (German) ==Wie vielen bereits bekannt ist, hat sich die Standortagentur Tirol dazu entschlossen – gemeinsam mit IMP – das Projekt „Tirol 2025“ zu starten, um strategische Handlungsfelder für Tirol in ausgewählten Branchen zu definieren. Und in der Zwischenzeit hat sich diesbezüglich viel getan.'''WAS BISHER GESCHAH...'''In den letzten Monaten wurden Gespräche mit hochkarätigen internationalen Expertinnen und Experten aus Wirtschaft, Wissenschaft und Kultur geführt sowie zahlreiche Zukunftsthemen rund um die Tätigkeitsfelder der Standortagentur untersucht. Aus dem generierten Wissen konnten daraufhin konkrete Zukunftshypothesen entwickelt werden, die von knapp 450 Befragten bezüglich Eintrittswahrscheinlichkeit sowie Art der Auswirkung auf Tirol und seinen Branchen bewertet wurden. Darauf aufbauend konnten aus weiteren 40 Interviews mit Tiroler Branchenexpert/innen zukünftige Kernthemen für die Branchencluster der Standortagentur identifiziert werden. '''DER NÄCHSTE SCHRITT...'''Im nächsten Schritt geht es nun darum, gemeinsam mit 8 bis 12 Experten pro Themencluster Lösungsansätze zu den zentralen Zukunftsherausforderungen für Unternehmen, für die Standortagentur sowie für die Politik zu entwickeln und zu diskutieren. Im Bereich Medizintechnik werden folgende Fragestellungen behandelt:* Wie könnten neue Geschäftsmodelle helfen die Erfolgsgeschichte der Tiroler Medizintechnikunternehmen auszubauen? * Was sind spannende, digitale Lösungsansätze um die Wettbewerbsfähigkeit Tiroler Medizintechnikunternehmen erhöhen zu können? * Wie können Tiroler Medizintechnikunternehmen durch eine branchenübergreifende Vernetzung (IT, Gesundheit,..) innovative Angebote entwickeln? * Wie müsste eine wirksame Förderpolitik für Tiroler Medizintechnikunternehmen aussehen? * Welche Vermarktungsansätze könnten Tiroler Medizintechnikunternehmen im Wettbewerb massiv weiterhelfen? * Welche Ansätze helfen Tiroler Medizintechnikunternehmen deren Effektivität und Effizienz in der Entwicklung und Herstellung zu steigern? * Welche Ansätze könnten (kleineren) Tiroler Medizintechnikunternehmen helfen, mit der Flut an neuen Regularien umzugehen? Ihr Mitwirken in diesem Prozess ist uns ein zentrales Anliegen, da es nur mithilfe von hochkarätigem Expertenwissen gelingen kann, effektive strategische Schritte in die Zukunft zu setzen.egische Schritte in die Zukunft zu setzen. +
'''FAT4BRAIN Advanced Virtual O2k-Workshop IOC149 on Amplex UltraRed, Virtual Event, 2021''' +
'''FAT4BRAIN Advanced Virtual O2k-Workshop IOC150 on TMRM and Calcium Green, Virtual Event, 2021''' +
'''FAT4BRAIN O2k-Workshop IOC159 on HRR for the assessment of mitochondrial bioenergetics.''' Riga, LV, 2023 +
'''FAT4BRAIN O2k-Workshop on high-resolution respirometry'''. Schroecken, Austria (2022 October 03-08). +
'''FAT4BRAIN Online Workshop: Brain energy metabolism in emotion and cognition, 2021''' +
'''FAT4BRAIN Online Workshop: Central regulatory mechanisms of energy metabolism, 2021''' +
'''FAT4BRAIN School IOC147 on mt-functionality assessment in CNS-related applications, Virtual Event, 2020''' +
'''FAT4BRAIN Symposium - Long COVID and acetylcarnitines: From preclinical models to clinical applications and translation potential, Jena, Germany, 2022''' +
'''FAT4BRAIN Symposium - Novel drug target and pathway identification, Riga, Latvia, 2023''' +
'''FAT4BRAIN Virtual O2k-Workshop IOC148 on HRR for the assessment of mitochondrial bioenergetics, Virtual Event, 2021''' +
'''FAT4BRAIN Workshop IOC 151 on mitochondrial function in CNS-related applications: from pre-clinical to clinical studies, Innsbruck AT, 2022''' +
'''FEBS Advanced course - Frontiers in Molecular Biochemistry of Mitochondria.''' Warsaw, Poland; 2006 June 09. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[OROBOROS O2k-Catalogue | O2k-Catalogue]] +
'''Fasching M, Fontana-Ayoub M, Gnaiger E … '''Fasching M, Fontana-Ayoub M, Gnaiger E (2018) Mitochondrial respiration medium - MiR06. Mitochondr Physiol Network 14.13(06):1-4.''' <div style="padding:0px;border: 1px solid #aaaaaa;margin-bottom:0px;margin-right:10px"><div style="font-size:100%;font-weight:bold;padding:0.2em;padding-right: 0.4em;padding-left: 0.4em;background-color:#eeeeee;border-bottom:1px solid #aaaaaa;text-align:left;">[[Image:O2k-support system.jpg|right|150px|link=http://wiki.oroboros.at/index.php/O2k-technical_support_and_open_innovation|O2k-technical support and open innovation]]: <big>Open the '''pdf document''' above.</big></div><div style="background-color:#ffffff;padding-top:0.2em;padding-right: 0.4em;padding-bottom: 0.2em;padding-left: 0.4em;">::::» Current O2k-series: '''[https://www.oroboros.at/index.php/product-category/products/o2k-packages/ NextGen-O2k Series XB and O2k Series J]'''::::» Current software versions DatLab 8.0: [[MitoPedia: DatLab]]::::* ''Further details:'' '''» [[MitoPedia: O2k-Open Support]]'''</div></div>Mitochondrial respiration medium MiR06 was developed for oxygraph incubations of mitochondrial preparations. MiR06 = MiR05 plus catalase. MiR06Cr = MiR06+creatine.:» Product: [[MiR05-Kit]]R05-Kit]] +
'''Fontana-Ayoub M, Fasching M, Gnaiger E … '''Fontana-Ayoub M, Fasching M, Gnaiger E (2016) Selected media and chemicals for respirometry with mitochondrial preparations. Mitochondr Physiol Network 03.02(18):1-10.'''Different media for tissue preparation and respiration are used in investigations of mitochondrial function. Initial decisions on the composition of media and chemicals are decisive for long-term studies and crucial for comparability of results. As a guideline, we summarize an update of our experience with media and chemicals for high-resolution respirometry with isolated mitochondria, permeabilized cells, muscle fibres and tissue homogenates. Whereas optimization is necessary for specific experimental protocols, standardization will improve the comparability of results obtained in different laboratories. Efforts towards standardization are important for the advancement of mitochondrial physiology.:» Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''Gnaiger E (2014) Service of the polarog … '''Gnaiger E (2014) Service of the polarographic oxygen sensor OroboPOS. Mitochondr Physiol Network 19.01(B01):19-24.''' '''This is an old version, which applies up to O2k-Series F and to DatLab 5.''': ''New version:'' '''[[MiPNet19.18B POS-service|»MiPNet19.18B POS-service]]'''[[MiPNet19.18B POS-service|»MiPNet19.18B POS-service]]''' +
'''Gnaiger E, Doeller JE, Kraus D, Shiva S … '''Gnaiger E, Doeller JE, Kraus D, Shiva S, Brookes PS, Darley-Usmar VM (2011) NO effect on mitochondrial oxygen kinetics at low oxygen. O2k workshop Report. Mitochondr Physiol Network 08.12(07).''' »[http://www.bioblast.at/index.php/File:MiPNet08.12_NO-O2kWorkshop.pdf Versions]A single pilot experiment was carried out during an O2k workshop on high-resolution respirometry (IOC22). Respiration of isolated rat liver mitochondria was inhibited by addition of NO, which increased the sensitivity to oxygen >25-fold when compared to the half-saturation oxygen pressure, p50, in the absence of NO. Oxygen kinetics followed a monophasic hyperbolic function up to 2.2 kPa with NO (p50=0.93 kPa), compared to the standard oxygen range to 1.1 kPa without NO (p50=0.035 kPa).[[Image:MiPNet08.12.jpg|400px|centre|thumb|Figure 1. Oxygen dependence of mt-respiration and competitive inhibition by NO. The full line shows oxygen kinetics at state 3 with pyruvate and malate in the absence of NO, measured in the physiological oxygen range (from Gnaiger et al. 1998a). Dotted lines show inhibition of respiration by the indicated NO concentrations, where measurements were performed with low-resoltion respirometry and are restricted to the high oxygen range (from Koivisto et al. 1977). Extrapolations into the physiological oxygen range (shaded region) suggest sigmoidal oxygen kinetics, which requires testing by direct measurements at low oxygen (modified after Gnaiger, Kuznetsov 2002).]][[Aguirre_2010_Biochim_Biophys_Acta| Reference: Biochim Biophys Acta 1797: 557-565 (2010)]]:» Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]]Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''Gnaiger E, Lassnig B (1997) DatLab 2. Analysis of oxygen kinetics. Mitochondr Physiol Network 02.05.''' :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue]] +
'''Gnaiger E, Reck M (1997) DatLab 2 Analysis. High resolution of data in the lab. Mitochondr Physiol Network 02.07: 1-72.''' :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue ]] +
'''Gnaiger E, Rieger G (1999) From step ti … '''Gnaiger E, Rieger G (1999) From step titration to ramp injection: Uncoupling by FCCP with TIP. Mitochondr Physiol Network 04.05.''':» Product: [[O2k-Catalogue: TIP2k|TIP2k]], [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]]Fully supported by the O2k-Core and control of the TIP2k by the software DatLab: The TIP2k can be programmed for multiple titrations and continuous injections. As an alternative to traditional step titration, the TIP offers the new option of ramp injection, providing maximum resolution of the concentration dependence of oxygen flux. This is illustrated by the recording of cellular respiratory flux as a function of a continuous increase of uncoupler (FCCP) concentration.''Titration:''Programmable, automatic titration regimes, with titration volumes of 0.05 to 250 µl, variable titration intervals and duration of titration pulses.''Injection:''Steady-state injection: Operation at quasi steady-states by continuous injection of substrates at limiting rates of consumption, providing new flexibility in experimental design by combining the technical advantages of closed and open systems. Programmable injection flows: 0.01 to 25 µl.s-1.Ramp injection (MiPNet04.05, see above): Ramp increase of effector concentrations by "continuous titration".DatLab software for feedback control by the the TIP2k: for steady-state respirometry at selected oxygen levels and pH-stat applications.ed oxygen levels and pH-stat applications. +
'''Highlights''' Heterozygous mice (αMHC& … '''Highlights'''Heterozygous mice (αMHC403/+) expressing the human hypertrophic cardiomyopathy (HCM) disease causing mutation ''Arg403Gln'' exhibit cardinal features of HCM.This study investigated the role of L-type Ca2+ channel (ICa-L) in regulating mitochondrial function in ''Arg403Gln'' (αMHC403/+) mice.Activation of ICa-L in αMHC403/+ mice caused a significantly greater increase in mitochondrial membrane potential and metabolic activity when compared to wild-type mice.Increases in mitochondrial membrane potential and metabolic activity were attenuated with ICa-L antagonists and when F-actin or β-tubulin were depolymerized.ICa-L antagonists may be effective in reducing the cardiomyopathy in HCM by altering metabolic activity.'''Summary'''Heterozygous mice (αMHC403/+) expressing the human disease-causing mutation ''Arg403Gln'' exhibit cardinal features of hypertrophic cardiomyopathy (HCM) including hypertrophy, myocyte disarray, and increased myocardial fibrosis. Treatment of αMHC403/+ mice with the L-type calcium channel (ICa-L) antagonist diltiazem has been shown to decrease left ventricular anterior wall thickness, cardiac myocyte hypertrophy, disarray, and fibrosis. However, the role of the ICa-L in the development of HCM is not known. In addition to maintaining cardiac excitation and contraction in myocytes, the ICa-L also regulates mitochondrial function through transmission of movement of ICa-L via cytoskeletal proteins to mitochondrial voltage-dependent anion channel. Here, the authors investigated the role of ICa-L in regulating mitochondrial function in αMHC403/+ mice. Whole-cell patch clamp studies showed that ICa-L current inactivation kinetics were significantly increased in αMHC403/+ cardiac myocytes, but that current density and channel expression were similar to wild-type cardiac myocytes. Activation of ICa-L caused a significantly greater increase in mitochondrial membrane potential and metabolic activity in αMHC403/+. These increases were attenuated with ICa-L antagonists and following F-actin or β-tubulin depolymerization. The authors observed increased levels of fibroblast growth factor-21 in αMHC403/+ mice, and altered mitochondrial DNA copy number consistent with altered mitochondrial activity and the development of cardiomyopathy. These studies suggest that the ''Arg403Gln'' mutation leads to altered functional communication between ICa-L and mitochondria that is associated with increased metabolic activity, which may contribute to the development of cardiomyopathy. ICa-L antagonists may be effective in reducing the cardiomyopathy in HCM by altering metabolic activity.to altered functional communication between ICa-L and mitochondria that is associated with increased metabolic activity, which may contribute to the development of cardiomyopathy. ICa-L antagonists may be effective in reducing the cardiomyopathy in HCM by altering metabolic activity. +
'''How mitochondria work''' 10 years afte … '''How mitochondria work'''10 years after setting the foundations of the [[Mitochondrial Physiology Society]] (MiP2003, Schröcken, Austria) our search continues as to what mitochondrial physiology is. Mitochondrial physiology is the study of “''how mitochondria work''”. Animal physiology is the study of “''how animals work''” - says the title of a textbook by Knut Schmidt-Nielsen. Comparative physiology derives its fascination from the diversity of form and function. Organismic variation is studied in diverse environments and in extremes of physiological performance, with explosive activities and high power output in short bursts or endurance over prolonged periods of time with high efficiency. Diversity is nature’s treasure and the subject of comparative physiology. The famous August Krogh principle – Krogh received the Nobel Prize in 1920 - is frequently cited [1,2]: “''For a large number of problems there will be some animal of choice or a few such animals on which it can be most conveniently studied.''” This principle was first formulated in 1975 by another Nobel laureate who received the Prize in 1953 for the metabolic cycle that carries his name, Sir Hans Krebs [3,4]. This direct link between one of the most famous mitochondrial biochemists and the August Krogh principle that “''epitomized the very essence of comparative physiology''” [2] immediately raises the question: Why was comparative mitochondrial physiology not established some 30 to 40 years ago?y not established some 30 to 40 years ago? +
'''Implementing DORA principles by publishing in Bioenergetics Communications - beyond counting papers''' - presentation by Erich Gnaiger, BEC Editor-in-chief +
'''Importance''': The American Heart Assoc … '''Importance''': The American Heart Association ideal cardiovascular health (CVH) score is associated with the risk of cardiovascular disease (CVD) and mortality. However, it is unclear whether the number of years spent in ideal CVH is associated with morbidity or with mortality.'''Objective:''' To evaluate whether living longer with a higher CVH score in midlife is associated with lower risk of hypertension, diabetes, chronic kidney disease, CVD and its subtypes (coronary heart disease, stroke, congestive heart failure, and peripheral artery disease), or all-cause mortality in later life.'''Design, Setting, and Participants''': This prospective cohort study used data from 1445 participants from 1991 to 2015 who participated in the community-based Framingham Heart Study Offspring investigation conducted in Massachusetts. The CVH scores of participants were assessed at examination cycles 5, 6, and 7 (1991-1995; 1995-1998; and 1998-2001, respectively). Individuals were excluded from analyses of the association between duration of CVH score and outcomes if they had the outcome of interest at the seventh examination. The median follow-up was approximately 16 years. Data were analyzed from April 2018 to October 2019. The CVH score categories were poor for scores 0 to 7, intermediate for scores 8 to 11, and ideal for scores 12 to 14. A composite score was derived based on smoking status, diet, physical activity, resting blood pressure levels, body mass index, fasting blood glucose levels, and total serum cholesterol levels.'''Main Outcomes and Measures''': Number of events and number at risk for each main outcome, including incident hypertension, diabetes, chronic kidney disease, CVD, and all-cause mortality, after the seventh examination.'''Results''': Of 1445 eligible participants, the mean (SD) age was 60 (9) years, and 751 (52 %) were women. Number of events/number at risk for each main outcome after the seventh examination were 348/795 for incident hypertension, 104/1304 for diabetes, 198/918 for chronic kidney disease, 210/1285 for CVD, and 300/1445 for all-cause mortality. At the seventh examination, participants mostly had poor (568 [39 %]) or intermediate (782 [54 %]) CVH scores. For each antecedent (before examination cycle 7) 5-year duration that participants had intermediate or ideal CVH, they were less likely to develop adverse outcomes (hazards ratios of 0.67 [95 % CI, 0.56-0.80] for incident hypertension, 0.73 [95 % CI, 0.57-0.93] for diabetes, 0.75 [95 % CI, 0.63-0.89] for chronic kidney disease, 0.73 [95 % CI, 0.63-0.85] for CVD, and 0.86 [95 % CI, 0.76-0.97] for all-cause mortality) relative to living the same amount of time in poor CVH (referent group). No effect modification was observed by age or by sex.'''Conclusions and Relevance''': These results suggest that more time spent in better CVH in midlife may have salutary cardiometabolic benefits and may be associated with lower mortality later in life.ciated with lower mortality later in life. +
'''International Course on High-Resolution … '''International Course on High-Resolution Respirometry - Satellite to 1st SMRM.''' Hyderabad, India; 2011 December 08:>> O2k-Workshop: [[Oroboros Events| Current dates]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''Introduction''' Low blood pressure, in … '''Introduction'''Low blood pressure, inadequate tissue oxygen delivery and mitochondrial dysfunction have all been implicated in the development of sepsis-induced organ failure. This study evaluated the effect on liver mitochondrial function of using norepinephrine to increase blood pressure in experimental sepsis.'''Methods'''Thirteen anaesthetized pigs received endotoxin (Escherichia coli lipopolysaccharide B0111:B4; 0.4 μg/kg per hour) and were subsequently randomly assigned to norepinephrine treatment or placebo for 10 hours. Norepinephrine dose was adjusted at 2-hour intervals to achieve 15 mmHg increases in mean arterial blood pressure up to 95 mmHg. Systemic (thermodilution) and hepatosplanchnic (ultrasound Doppler) blood flow were measured at each step. At the end of the experiment, hepatic mitochondrial oxygen consumption (high-resolution respirometry) and citrate synthase activity (spectrophotometry) were assessed.'''Results'''Mean arterial pressure (mmHg) increased only in norepinephrine-treated animals (from 73 [median; range 69 to 81] to 63 [60 to 68] in controls [''P'' = 0.09] and from 83 [69 to 93] to 96 [86 to 108] in norepinephrine-treated animals [''P'' = 0.019]). Cardiac index and systemic oxygen delivery (''D''O2) increased in both groups, but significantly more in the norepinephrine group (''P'' < 0.03 for both). Cardiac index (ml/min per·kg) increased from 99 (range: 72 to 112) to 117 (110 to 232) in controls (''P'' = 0.002), and from 107 (84 to 132) to 161 (147 to 340) in norepinephrine-treated animals (''P'' = 0.001). ''D''O2 (ml/min per·kg) increased from 13 (range: 11 to 15) to 16 (15 to 24) in controls (''P'' = 0.028), and from 16 (12 to 19) to 29 (25 to 52) in norepinephrine-treated animals (''P'' = 0.018). Systemic oxygen consumption (systemic VO2) increased in both groups (''P'' < 0.05), whereas hepatosplanchnic flows, ''D''O2 and ''V''O2 remained stable. The hepatic lactate extraction ratio decreased in both groups (''P'' = 0.05). Liver mitochondria Complex I-dependent and II-dependent respiratory control ratios were increased in the norepinephrine group (Complex I: 3.5 [range: 2.1 to 5.7] in controls versus 5.8 [4.8 to 6.4] in norepinephrine-treated animals [''P'' = 0.015]; Complex II: 3.1 [2.3 to 3.8] in controls versus 3.7 [3.3 to 4.6] in norepinephrine-treated animals [''P'' = 0.09]). No differences were observed in citrate synthase activity.'''Conclusion'''Norepinephrine treatment during endotoxaemia does not increase hepatosplanchnic flow, oxygen delivery or consumption, and does not improve the hepatic lactate extraction ratio. However, norepinephrine increases the liver mitochondria Complex I-dependent and II-dependent respiratory control ratios. This effect was probably mediated by a direct effect of norepinephrine on liver cells. direct effect of norepinephrine on liver cells. +
'''Introduction''' Mitochondrial disorders … '''Introduction'''Mitochondrial disorders are extremely heterogeneous and can involve single tissue, such as the optic nerve to widespread pathologies including muscle disorders, peripheral neuropathies, encephalopathy, cardiomyopathies or complex multisystem disorders. The age at onset ranges from neonatal to adult life. Mitochondrial dysfunction is a relatively common disorder but the clinical and genetic variability makes it difficult to diagnose. Our primary hypothesis is that disturbance in mitochondrial respiratory chain can be diagnosed with blood test and skin biopsy, by combining structural (Blue native page) and functional information, with high-resolution respirometry of the respiratory chain in blood cells. This rapid diagnostic method can be used to diagnose the flora of undiagnosed and unknown encephalopathy in children today. '''Methods'''Our aim is to 1. Establish reference material for mitochondrial normal function in children through high resolution respirometry by diagnosing thrombocytes and fibroblasts. We also want to establish reference material for structural information with Blue Native PAGE (BNP) in fibroblasts. 2. We want to use these methods in children with known mitochondrial disease to confirm that our methods are usefull.3. We want to compare our methods to known methods today for diagnoses of mitochondrial disease (muscle biopsy).4. We want to see the benefits of treatment by comparing results through BNP and respirometry before and after treatment. 5. We want to use these methods for diagnosis of unknown encephalopathy in children.'''Results'''We have started collecting reference material from children from 0-17 years old. We collect blood and skin biopsy from healthy children that are having a small operation at the University Hospital in Lund. Our aim is to collect reference material from 60 children in different age groups. We also collect blood and skin biopsy from 30 newborn babies from the umbilical cord.We have also done respirometry on children that have both suspected mitochondrial disease and children with known mitochondrial disease. The results are promising. We have also taken skin biopsy from these children but we do not know the outcome yet. We have also started using our methods to look at children with autism and other encephalopathy. '''Conclusion'''Mitochondrial dysfunction has been difficult to diagnose. Our methods give us the opportunity to diagnose mitochondrial dysfunction in unknown encephalopathy in children by a more rapid and simple way than before.y a more rapid and simple way than before. +
'''Introduction''' Mitochondrial dysfuncti … '''Introduction'''Mitochondrial dysfunction has been suggested as a contributing factor to the pathogenesis of sepsis-induced multiple organ failure. Also, restoration of mitochondrial function, known as mitochondrial biogenesis, has been implicated as a key factor for the recovery of organ function in patients with sepsis. Here we investigated temporal changes in platelet mitochondrial respiratory function in patients with sepsis during the first week after disease onset.'''Methods'''Platelets were isolated from blood samples taken from 18 patients with severe sepsis or septic shock within 48 hours of their admission to the intensive care unit. Subsequent samples were taken on day 3 to 4 and day 6 to 7. Eighteen healthy blood donors served as controls. Platelet mitochondrial function was analyzed by high-resolution respirometry. Endogenous respiration of viable, intact platelets suspended in their own plasma or PBS glucose was determined. Further, in order to investigate the role of different dehydrogenases and respiratory complexes as well as to evaluate maximal respiratory activity of the mitochondria, platelets were permeabilized and stimulated with complex-specific substrates and inhibitors.'''Results'''Platelets suspended in their own septic plasma exhibited increased basal non-phosphorylating respiration (state 4) compared to controls and to platelets suspended in PBS glucose. In parallel, there was a substantial increase in respiratory capacity of the Electron transfer-pathway from day 1 to 2 to day 6 to 7 as well as compared to controls in both intact and permeabilized platelets oxidizing Complex I and/or II-linked substrates. No inhibition of respiratory complexes was detected in septic patients compared to controls. Non-survivors, at 90 days, had a more elevated respiratory capacity at day 6 to 7 as compared to survivors. Cytochrome c increased over the time interval studied but no change in mitochondrial DNA was detected.'''Conclusions'''The results indicate the presence of a soluble plasma factor in the initial stage of sepsis inducing uncoupling of platelet mitochondria without inhibition of the Electron transfer-pathway. The mitochondrial uncoupling was paralleled by a gradual and substantial increase in respiratory capacity. This may reflect a compensatory response to severe sepsis or septic shock, that was most pronounced in non-survivors, likely correlating to the severity of the septic insult.ting to the severity of the septic insult. +
'''Introduction''': Alzheimer's disease (A … '''Introduction''': Alzheimer's disease (AD) is the most frequent neurodegenerative disease, characterized by progressive decline in variety of higher brain functions - memory, orientation, and thinking. According to increasing evidences, mitochondrial insufficiencies contribute to pathology of AD; changes were described in AD brains, blood cells and human fibroblasts.'''Objectives''': On molecular level, oxygen and glucose metabolism is altered and energy metabolism is impaired.Mitochondrial abnormalities and alterations in mitochondrial enzymes, especially Complex I and cytochrome ''c'' oxidase, were observed. However, the cause and important aspects of AD mechanism have not yet been sufficiently clarified.'''Aims''': The aim of our study was to find whether kinetics of oxygen consumption is modified in AD patients. Further, we afford to suggest parameters that could be suitable as AD markers.'''Methods''': AD patients and healthy control group were included in the study. Respiratory rate of mitochondria, as measure of total activity of the system of oxidative phosphorylation (OXPHOS), was measured in mitochondria using oxygraph with Clark-type electrodes. High-resolution respirometry was performed in intact as well as in permeabilized platelets.'''Results''': Our results indicate significantly lower respiratory rate in intact platelets as well as lower respiratory capacity of Electron transfer-pathway in patients with AD compared to controls.'''Conclusions''': We propose that decrease in oxygen consumption may participate in pathophysiology of AD, and respiratory rate in platelets could be AD marker.tory rate in platelets could be AD marker. +
'''Introduction:''' Hydrogen sulfide (H< … '''Introduction:''' Hydrogen sulfide (H2S) is a potent inhibitor of cytochrome c oxidase (COX) and, thus, of mitochondrial respiration [1]. Since H2S was reported to induce a suspended animation-like status characterized by reduced energy expenditure and hypothermia [2], we sought to determine the effect of hypothermia on mitochondrial respiratory capacity and H2S-related COX inhibition. We further studied the influence of variations in pH on both variables.'''Methods:''' All measurements were conducted in digitonin-permeabilised cultured peritoneal macrophages using high-resolution respirometry [3] (Oxygraph-2 k, Oroboros, Austria). Maximum mitochondrial respiration (1 to 2 Mio cells/ml respiration medium) was achieved in the uncoupled state by adding pyruvate, malate, glutamate and succinate as respiratory substrates. Then, in one of the two chambers of the oxygraph, mitochondrial respiration was inhibited stepwise by incremental concentrations of the H2S donor Na2S (1 to 64 μM). In the parallel chamber, the identical inhibitor titration sequence was preceded by the inhibition of the respiratory chain by rotenone and antimycin A followed by the selective stimulation of CIV after addition of ascorbate and TMPD. COX excess capacity (% of ET-pathway) was calculated based on the ratio of inhibition of mitochondrial respiration with full operating respiratory chain versus the CIV-stimulated condition. This experimental sequence was repeated at 37 °C and 25 °C with a medium pH of 7.1 and then at 37°C with a pH of 6.8 and 7.7.'''Results:''' CIV excess capacity (median (quartiles)) was significantly higher at 25 °C than at 37 °C (134 (113; 140) vs 61 (47; 79)), most likely due to the almost halved mitochondrial respiratory capacity at hypothermia (50 (37; 63) vs 95 (81; 103) pmol O2/s × Mio cells). Changing the medium pH from 6.8 to 7.7 significantly increased the COX excess capacity (91 (79; 103) vs 71 (64; 82) pmol O2/s × Mio cells), which again was related to the significantly lower mitochondrial respiratory capacity with more acidic conditions (80 (70; 89) vs 94 (85; 98)).'''Conclusions:''' Our results suggest that COX excess capacity is temperature as well as pH dependent in peritoneal macrophages. This effect may protect cells from H2S toxicity at low temperatures and high pH values. in peritoneal macrophages. This effect may protect cells from H2S toxicity at low temperatures and high pH values. +
'''Journal publication 2021-11-16 in [[Fischer 2021 Antioxidants |»Antioxidants«]]'' … '''Journal publication 2021-11-16 in [[Fischer 2021 Antioxidants |»Antioxidants«]]'''</big>[[File:Fischer_2021_MitoFit_Fe_liver - graphical abstract.png|right|500px|Graphical abstract]] Iron is an essential co-factor for many cellular metabolic processes, and mitochondria are main sites of utilization. Iron accumulation promotes production of reactive oxygen species (ROS) via the catalytic activity of iron species. Herein, we investigated the consequences of dietary and genetic iron overload on mitochondrial function. C57/BL6N wildtype and ''Hfe-/-'' mice, the latter a genetic hemochromatosis model, received either normal diet (ND) or high iron diet (HI) for two weeks. Liver mitochondrial respiration was measured using high-resolution respirometry along with analysis of expression of specific proteins and ROS production. HI promoted tissue iron accumulation and slightly affected mitochondrial function in wildtype mice. Hepatic mitochondrial function was impaired in ''Hfe-/-'' mice on ND and HI. Compared to wildtype mice, ''Hfe-/-'' mice on ND showed increased mitochondrial respiratory capacity. ''Hfe-/-'' mice on HI showed very high liver iron levels, decreased mitochondrial respiratory capacity and increased ROS production associated with reduced mitochondrial aconitase activity. Although ''Hfe-/-'' resulted in increased mitochondrial iron loading, the concentration of metabolically reactive cytoplasmic iron and mitochondrial density remained unchanged. Our data shows multiple effects of dietary and genetic iron loading on mitochondrial function and linked metabolic pathways, providing an explanation for fatigue in iron-overloaded hemochromatosis patients and suggests iron reduction therapy for improvement of mitochondrial function. chromatosis patients and suggests iron reduction therapy for improvement of mitochondrial function. +
'''Journal publication 2022-03-03 in [[Zdrazilova 2022 PLOS ONE |»'''PLOS ONE 17:e0264496'''«]]'' … '''Journal publication 2022-03-03 in [[Zdrazilova 2022 PLOS ONE |»'''PLOS ONE 17:e0264496'''«]]'''Version 1 ('''v1''') '''2021-09-21''' [https://www.mitofit.org/images/1/15/Zdrazilova_2021_MitoFit_ace-sce.pdf doi:10.26124/mitofit:2021-0007]Measurement of oxygen consumption of cultured cells is widely used for diagnosis of mitochondrial diseases, drug testing, biotechnology and toxicology. Fibroblasts are cultured in monolayers but physiological measurements are carried out in suspended or attached cells. We address the question whether respiration differs in attached and suspended cells using multiwell respirometry (Agilent Seahorse XF24) and high-resolution respirometry (Oroboros O2k), respectively. Respiration of human dermal fibroblasts measured in culture medium was baseline-corrected for residual oxygen consumption and expressed as oxygen flow per cell.No differences were observed in ROUTINE respiration of living cells and LEAK respiration obtained after inhibition of ATP synthase by oligomycin. Multiple steps of uncoupler titrations in the O2k allowed for evaluation of maximum electron transfer capacity, which was higher than respiration obtained in the XF24 due to a limitation to two uncoupler titrations.Quantitative evaluation of respiration measured in different platforms revealed that short-term suspension of fibroblasts did not affect respiratory activity and coupling control. Consistent results obtained with different platforms provide a test for reproducibility and allow for building an extended respirometric database. extended respirometric database. +
'''Journal publication 2022-03-21 in [[Fischer 2022 Metabolites |»Metabolites«]]'' … '''Journal publication 2022-03-21 in [[Fischer 2022 Metabolites |»Metabolites«]]'''</big>Iron is an essential component for metabolic processes including oxygen transport within hemoglobin, tricarboxylic acid (TCA) cycle activity and mitochondrial energy transformation. Iron deficiency can thus lead to metabolic dysfunction and eventually result in iron deficiency anemia (IDA) which affects approximately 1.5 billion people worldwide. Using a rat model of IDA induced by phlebotomy, we studied the effects of IDA on mitochondrial respiration in peripheral blood mononuclear cells (PBMCs) and liver. Furthermore, we evaluated whether mitochondrial function evaluated by high-resolution respirometry in PBMCs reflects corresponding alterations in the liver. Surprisingly, mitochondrial respiratory capacity was increased in PBMCs from rats with IDA compared to controls. In contrast, mitochondrial respiration remained unaffected in livers from IDA rats. Of note, citrate synthase activity indicated an increased mitochondrial density in PBMCs, whereas it remained unchanged in the liver, partly explaining the different responses of mitochondrial respiration in PBMCs and liver. Taken together, these results indicate that mitochondrial function determined in PBMCs cannot serve as a valid surrogate for respiration in the liver. Metabolic adaptions to iron deficiency resulted in different metabolic reprogramming in the blood cells and liver tissue. ng in the blood cells and liver tissue. +
'''KEY POINTS:''' Genetic mutations in car … '''KEY POINTS:'''Genetic mutations in cardiac troponin I (cTnI) are associated with development of hypertrophic cardiomyopathy characterised by myocyte remodeling, disorganisation of cytoskeletal proteins and altered energy metabolism. The L-type Ca2+ channel is the main route for calcium influx and critical to cardiac excitation and contraction. The channel also regulates mitochondrial function in the heart by a functional communication between the channel and mitochondria via the cytoskeletal network. We find that L-type Ca2+ channel kinetics are altered in cTnI-G203S cardiac myocytes, and that activation of the channel causes a significantly greater increase in mitochondrial membrane potential and metabolic activity in cTnI-G203S cardiac myocytes. These responses occur as a result of impaired communication between the L-type Ca2+ channel and cytoskeletal protein F-actin, involving decreased movement of actin-myosin, and block of mitochondrial VDAC, resulting in a 'hypermetabolic' mitochondrial state. We propose that L-type Ca2+ channel antagonists such as diltiazem may be effective in reducing the cardiomyopathy by normalising mitochondrial metabolic activity.'''ABSTRACT:'''Genetic mutations in cardiac troponin I (cTnI) account for 5% of families with hypertrophic cardiomyopathy (HCM). HCM is associated with disorganisation of cytoskeletal proteins and altered energy metabolism. The L-type Ca2+ channel (ICa-L ) plays an important role in regulating mitochondrial function. This involves a functional communication between ICa-L and mitochondria via the cytoskeletal network. We investigate the role of ICa-L in regulating mitochondrial function in 25-30-week old cardiomyopathic mice expressing human disease causing mutation Gly203Ser in cTnI (cTnI-G203S). The inactivation rate of ICa-L is significantly faster in cTnI-G203S myocytes (cTnI-G203S: τ1 = 40.68 ± 3.22, n = 10 versus wt: τ1 = 59.05 ± 6.40, n = 6, P < 0.05). Activation of ICa-L caused a greater increase in mitochondrial membrane potential (Ψm , 29.19 ± 1.85%, n = 15 versus wt: 18.84 ± 2.01%, n = 10, P < 0.05) and metabolic activity (24.40 ± 6.46%, n = 8 versus wt: 9.98 ± 1.57%, n = 9, P < 0.05). The responses occurred due to impaired communication between ICa-L and F-actin, involving lack of dynamic movement of actin-myosin, and block of mitochondrial VDAC. Similar responses were observed in pre-cardiomyopathic mice. ICa-L antagonists nisoldipine and diltiazem decreased Ψm to basal levels. We conclude that the Gly203Ser mutation leads to impaired functional communication between ICa-L and mitochondria resulting in a 'hypermetabolic' state. This may contribute to development of cTnI-G203S cardiomyopathy because the response is present in young pre-cardiomyopathic mice. ICa-L antagonists may be effective in reducing the cardiomyopathy by altering mitochondrial function. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.e is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved. +
'''Klinische MitochondrienMedizin und Umwe … '''Klinische MitochondrienMedizin und Umweltmedizin 2015, Internationales Wissenschaftsforum der Universität, Heidelberg, DE.'''Im März 2015 startet in Heidelberg bereits vierte Auflage eines erfolgreichen Curriculums Klinische MitochondrienMedizin und Umweltmedizin. Die Veranstaltung ist als ärztliche Fortbildung mit Ärztekammer-, Zahnärzte- und Apothekerkammer-Anerkennung und als Wahlpflichtmodul des KWKM-Masterstudiengangs an der Europa-Universität Viadrina konzipiert. An sechs intensiven Wochenenden (freitags und samstags) werden in Vorträgen und Übungen:* Grundlagen der Mitochondrien-Medizin,* aktuelle Forschungsergebnisse,* Diagnosemethoden und* Therapieverfahren der mitochondrialen Medizinu.a. in Verbindung mit der Umweltmedizin, Umwelt-Zahnmedizin, Frauenheilkunde und Psychotherapie erläutert. Ergänzend zu dem theoretischen Teil werden Hospitanten-Tage im Centrum für Integrative Medizin in Speyer angeboten, welches auf dem Gebiet der Mitochondrien-Medizin spezialisiert ist.r Mitochondrien-Medizin spezialisiert ist. +
'''Klinische MitochondrienMedizin und Umwe … '''Klinische MitochondrienMedizin und Umweltmedizin 2016, Internationales Wissenschaftsforum der Universität, Heidelberg, DE.''' [[Media:MitochondrialMedicine_2016.pdf| »Flyer]] Im März 2016 startet in Heidelberg bereits fünfte Auflage eines erfolgreichen Curriculums '''Klinische MitochondrienMedizin und Umweltmedizin'''. Die Veranstaltung ist als ärztliche Fortbildung mit Ärztekammer-, Zahnärzte- und Apothekerkammer-Anerkennung und als Wahlpflichtmodul des KWKM-'''Masterstudiengangs an der Europa-Universität Viadrina''' konzipiert. An sechs intensiven Wochenenden (freitags und samstags) werden in Vorträgen und Übungen:* Grundlagen der Mitochondrien-Medizin* Aktuelle Forschungsergebnisse* Diagnosemethoden* Therapieverfahren der mitochondrialen Medizinu.a. in Verbindung mit der Umweltmedizin, Umwelt-Zahnmedizin, Frauenheilkunde undPsychotherapie erläutert. Ergänzend zu dem theoretischen Teil werden Hospitanten-Tage im BioMedical Center in Speyer angeboten, welches auf dem Gebiet der Mitochondrien-Medizin spezialisiert ist. Mehr Informationen finden Sie hier: http://www.mito-medizin.de/fortbildung/ '''Termine 2016:''' :* Kurs A: 04. - 05.03:* Kurs B: 15. - 16.04:* Kurs C: 20. - 21.05:* Kurs D: 17. - 18.06:* Kurs E: 09. - 10.09:* Kurs F: 11. - 12.11Kurs E: 09. - 10.09 :* Kurs F: 11. - 12.11 +
'''Kuznetsov AV, Gnaiger E. Laboratory pro … '''Kuznetsov AV, Gnaiger E. Laboratory protocol: Complex I (NADH:Ubiquinone Oxidoreductase, EC 1.6.5.3). Mitochondrial membrane enzyme. Mitochondr Physiol Network 08.15.'''Complex I (CI) is the segment of the electron transport system (integral enzyme of the inner mitochondrial membrane) responsible for electron transfer from NADH to ubiquinone. CI is sensitive to different pathologies, particularly to oxidative stress, which is involved in ischemia-reperfusion injury, anoxia/ reoxygenation, aging, etc (Kuznetsov et al 2004; Rouslin & Millard 1981; Rouslin & Ranganathan, 1983; Rouslin, 1983). For the assessment of CI activity, among the ubiquinone isoprenologs, it is most convenient to use ubiquinone-1 (CoQ1) as electron acceptor, because of its relative water solubility. Importantly, CoQ1 yields one of the lowest rotenone insensitive rates and a high enzymatic rate. It is, therefore, the best electron acceptors for the CI assay.:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue]][[Oroboros O2k-Catalogue]] +
'''Kuznetsov AV, Gnaiger E. Laboratory pro … '''Kuznetsov AV, Gnaiger E. Laboratory protocol: Lactate dehydrogenase. Cytosolic marker enzyme. Mitochondr Physiol Network 08.18.''' Lactate dehydrogenase (EC 1.1.1.27) is an enzyme, which catalyzes the last step in glycolysis. LDH is a soluble enzyme and localized in the cytosol (cytoplasm). LDH, therefore, is used as a quantitative marker enzyme for the intact cell, its activity providing information on cellular glycolytic capacity (Renner et al, 2003). Measurement of LDH release (leakage) is an important and frequently applied test for cellular membrane permeabilization (rupture) and severe irreversible cell damage. LDH leakage normally correlates well with CK release and the trypan blue viability test.:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue]][[Oroboros O2k-Catalogue]] +
'''Lassnig B, Gnaiger E. Laboratory protoc … '''Lassnig B, Gnaiger E. Laboratory protocol: Isolation of rat liver mitochondria. Mitochondr Physiol Network 08.13.''' <div style="padding:0px;border: 1px solid #aaaaaa;margin-bottom:0px;margin-right:10px"><div style="font-size:100%;font-weight:bold;padding:0.2em;padding-right: 0.4em;padding-left: 0.4em;background-color:#eeeeee;border-bottom:1px solid #aaaaaa;text-align:left;">[[Image:O2k-support system.jpg|right|150px|link=http://wiki.oroboros.at/index.php/O2k-technical_support_and_open_innovation|O2k-technical support and open innovation]]: <big>Open the '''pdf document''' above.</big></div><div style="background-color:#ffffff;padding-top:0.2em;padding-right: 0.4em;padding-bottom: 0.2em;padding-left: 0.4em;">::::» Current O2k-series: '''[https://www.oroboros.at/index.php/product-category/products/o2k-packages/ NextGen-O2k Series XB and O2k Series J]'''::::» Current software versions DatLab 8.0: [[MitoPedia: DatLab]]::::* ''Further details:'' '''» [[MitoPedia: O2k-Open Support]]'''</div></div>:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue]]roboros O2k-Catalogue]] +
'''Lectures on High-Resolution Respirometr … '''Lectures on High-Resolution Respirometry and Oroboros O2k Demonstration at BTK 1994.''' Innsbruck, Tyrol, Austria; 1994 September.:>> O2k-Workshop: [[Oroboros Events| Current dates]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''Long Night of Research 2016: MitoFit – Training for the powerhouses of your blood- and muscle cells. Innsbruck, AT.''' +
'''Long Night of Research 2018: The diagnostic bioenergetic report – a milestone on the way to mitochondrial fitness and physical well-being. Innsbruck, AT.''' +
'''Long Night of Research 2020: The diagnostic bioenergetic report – a milestone on the way to mitochondrial fitness and physical well-being. Virtual Event.''' +
'''Meeting of the European Society for Clinical Investigation, Paris, FR''' +
'''Metabolic Energetics in Ecological, Cellular and Biomedical Research.''' Aberystwyth Wales United Kingdom; 1993 March 01-03. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''MiPschool, Obergurgl, Austria, 2023: Mitochondrial structure and function, respiratory supercomplexes, and respiratory control''' +
'''MitoCom Lecture''' '''2011-Nov-10, 8:1 … '''MitoCom Lecture''''''2011-Nov-10, 8:15 - 09:45'''. Medical University Innsbruck, Anichstr. 25, Chirurgie (8-U1-517) Seminarraum 2Speaker: '''[[Jezek P|Prof. Dr. Petr Jezek, Prague]]'''Host: [[Gnaiger E|Erich Gnaiger, DSL, MitoCom Tyrol]]'''Abstract''': Three-dimensional (3D) super-resolution microscopy, using a biplane detection scheme, termed biplane photo-activated localization microscopy (Biplane FPALM), enables imaging of volumes as thick as whole cells and reveals otherwise unaccessible details of cellular organization [1]. Hence, we attempted to visualize mitochondrial reticulum via the matrix space loaded with mitochondria-addressed Eos, while transfecting cells by lentiviral expression. Our 3D images of single Eos molecules in the matrix space have proven the continuous character of mitochondrial reticulum tubules, i.e., an existence of a highly interconnected major mitochondrial reticulum in insulinoma Ins1E and oxidative-phosphorylation-dependent glutaminolytic hepatoma HepG2 cells [2] (Figure).Also, using Eos-conjugate of mitochondrial transcription factor-A (TFAM), we have imaged nucleoids of mitochondrial DNA (mtDNA) in which TFAM represents a major assessor protein. Using PA-CFP2-TFAM and mitochondria-addressed Eos, the first 3D two color super-resolution images were obtained for mitochondrial reticulum together with the distribution of mt nucleoids in it. In intact cells we have found mt nucleoids of a narrow size distribution. The Biplane FPALM technique has proven to be robust and reliable for imaging of mitochondrion and related substructures.Supported by grants P302/10/0346 (GACR); ME09029 (Czech Ministry of Education); IAA500110701, and M200110902 (Academy of Sciences).) and 1R01GM091791-02 (NIH). Disclosure statement: J.B. declares significant financial interest in Vutara, Inc.[1] Juette MF, Gould TJ, Lessard MD, Mlodzianoski MJ, Nagpure BS, Bennett BT, Hess ST, Bewersdorf J (2008) 3D sub-100 nm resolution by biplane fluorescence photoactivation localization microscopy. Nat. Methods 5: 527-529.[2] Mlodzianoski MJ, Schreiner JM, Callahan SP, Smolková K, Dlasková A, Šantorová J, Ježek P, Bewersdorf J (2011) Sample drift correction in 3D fluorescence photoactivation localization microscopy. Opt. Express. 19: 15009-15019.microscopy. Opt. Express. 19: 15009-15019. +
'''MitoFit Open Seminar on respiration, cryopreservation and viability test in human blood cells'''. Innsbruck, AT +
'''Mitochondrial Medicine 2016, Seattle, W … '''Mitochondrial Medicine 2016, Seattle, WA, USA.''' The [[United Mitochondrial Disease Foundation]] Symposium has been recognized by many researchers, scientists, and families as THE symposium for mitochondrial disease in the world. 10 years ago, the UMDF had only a handful of exhibitors and less than 200 scientific attendees. We now have more exhibitors than space at times and close to 600 attendees … representing almost every state in the United States and more than 15 different countries from around the world.different countries from around the world. +
'''Mitochondrial Physiology (MiP) ''contin … '''Mitochondrial Physiology (MiP) ''continues a tradition of rigorous mitochondrial bioenergetics'' '''([http://www.mitophysiology.org quoting the International MiPsociety]). The company [[Oroboros Instruments]] Corp. values this tradition as a basis of our continuous instrumental development, which is part of our concept of Corporate Social Responsibility. In this spirit and with emphasis on our Educational Responsibility, we initiated and support the ''[[MiP-Collection]]''.[[MiP-Collection]]''. +
'''Mitochondrial capacity''': [[OXPHOS]] … '''Mitochondrial capacity''': [[OXPHOS]] capacity is evaluated in isolated mitochondria (mt) and permeabilized cells with physiological substrate cocktails to reconstitute tricarboxylic acid cycle function. As a consequence, convergent electron flow from Complexes CI+II of the electron transfer-pathway ([[ET-pathway]]) to the [[Q-junction]] exerts an additive effect on flux [1].'''Oxygen kinetics of mt-respiration''': The apparent ''K''m,O2 or ''c''50 [µM] (''p''50 [kPa]) of mt-respiration increases linearly with respiratory capacity controlled by metabolic state, from 0.2 to 1.6 µM determined by [[high-resolution respirometry]]. O2 gradients are significant only in large cells including cardiomyocytes. The apparent ''p''50 increases 100-fold in permeabilized muscle fibers due to diffusion gradients [2].'''mt-function at ''V''O2max''': Aerobic capacity of the human leg muscle exceeds maximum O2 uptake of isolated mitochondria [3] and v. lateralis during ''V''O2max [4]. Therefore, oxygen supply limits aerobic performance, proportional to the apparent mt-excess capacity [5]. mt-respiration is more sensitive to average ''p''O2 in heterogenous tissues than under homogenous conditions in vitro. Tissue heterogeneity increases the kinetic dependence of flux on average intracellular ''p''O2. High mt-density reinforces the steepness of oxygen gradients and oxygen heterogeneity in the tissue, contributing to the O2 limitation in athletic vs sedentary individuals at ''V''O2max [6]. This provides a functional rationale for the observation that hypoxia does not specifically trigger mt-biogenesis [7].Contribution to K-Regio ''[[MitoCom_O2k-Fluorometer|MitoCom Tyrol]]''.[1] [[Gnaiger 2009 Int J Biochem Cell Biol|Gnaiger 2009]]; [[Lemieux_2011_Int J Biochem Cell Biol|Lemieux et al 2011 Int J Biochem Cell Biol]] [2] [[Gnaiger_2003_Adv Exp Med Biol|Gnaiger 2003]]; [[Scandurra_2010_Adv Exp Med Biol|Scandurra, Gnaiger 2010 Adv Exp Med Biol]]. [3] Rasmussen et al 2001 AJP.[4] [[Boushel_2011_Mitochondrion|Boushel et al 2011 Mitochondrion]].[5] [[Gnaiger_1998_J_Exp_Biol|Gnaiger et al 1998 JEB]].[6] Richardson et al; Haseler et al JAP.[7] [[Pesta_2011_AJP|Pesta et al 2011 AJP]]; [[Jacobs_2011_J_Appl_Physiol|Jacobs et al 2011 JAP]].Jacobs_2011_J_Appl_Physiol|Jacobs et al 2011 JAP]]. +
'''Note''': Subscript ‘§’ indicates throug … '''Note''': Subscript ‘§’ indicates throughout the text those parts, where ''potential differences'' provide a mathematically correct but physicochemically incomplete description and should be replaced by ''stoichiometric potential differences'' ([[Gnaiger 1993 Pure Appl Chem |Gnaiger 1993b]]). A unified concept on vectorial motive transformations and scalar chemical reactions will be derived elsewhere (Gnaiger, in prep.). Appreciation of the fundamental distinction between ''differences of potential'' versus ''differences of stoichiometric potential'' may be considered a key to critically evaluate the arguments presented in Section 3 on the protonmotive force. Since this discussion appears to be presently beyond the scope of a MitoEAGLE position statement, Section 3 is removed from the next version and [[Gnaiger 2019 MitoFit Preprint Arch |'''final manuscript''']]. This section should become a topic of discussion within [[WG1 MitoEAGLE protocols, terminology, documentation |Working Group 1]] of the MitoEAGLE consortium, following a primary peer-reviewed publication of the concept of stoichiometric potential differences.t of stoichiometric potential differences. +
'''O2k-International course on high-resolu … '''O2k-International course on high-resolution respirometry and MiPNet meeting.''' Schroecken, Voralberg, Austria; 2004 September 15-21.:>> O2k-Workshop: [[Oroboros Events| Current dates]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry and MiPNet workshop.''' Schroecken, Voralberg, Austria; 2006 December 13 to 17. :>> O2k-Workshop: [[Oroboros Events]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry and ROS/NO detection.''' Schroecken, Voralberg, Austria; 2005 September 13-16. +
'''O2k-International course on high-resolution respirometry.''' 2007 August 24, 9:00 a.m. to 3:00 p.m. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' 2007 July 18-22. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' 2007 September 1 and 6. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' Gainsville, USA; 2009 February 23-25. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' Schroecken, Voralberg, Austria; 2004 December 9-13. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' Schroecken, Voralberg, Austria; 2007 April 13 to 17. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' Schroecken, Voralberg, Austria; 2007 December 12-16. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' Schroecken, Voralberg, Austria; 2008 April 04-08. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' Schroecken, Voralberg, Austria; 2009 December 11 to 16. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' Schroecken, Voralberg, Austria;2009 April 18 to 22. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' Schroecken, Voralberg,Austria; 2009 July 30 to August 04. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry.''' Schroecken,Voralberg, Austria; 2008 July 12-16. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry: O2k, TIP-2k and DatLab 4.''' Schroecken, Voralberg, Austria; 2006 August 18-22. +
'''O2k-International course on high-resolu … '''O2k-International course on high-resolution respirometry: Oroboros O2k, TIP-2k and DatLab 4.''' Schroecken, Voralberg, Austria; 2006 April 21-25.:>> O2k-Workshop: [[Oroboros Events| Current dates]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-International course on high-resolution respirometry: Oxygraph-2k, TIP-2k and DatLab 4.''' Schroecken, Voralberg, Austria; 2005 April 08-10. +
'''O2k-MultiSensor Workshop.''' Schroecken, Voralberg, Austria;2010 April 12 to 16. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Protocol for Oxygen flux''' In a … '''O2k-Protocol for Oxygen flux''' In a closed oxygraph chamber, the oxygen concentration declines over time as a result of respiratory processes. The time derivative, therefore, is a negative number. Why is then the ‘rate of oxygen consumption’ not expressed as a negative value? Why is the term ‘oxygen flux’ used in this context of chemical reactions? The rationale is based on fundamental concepts of physical chemistry and non-equilibrium thermodynamics.[[Image:O2k-Protocols.jpg|right|150px|link=http://www.oroboros.at/?o2k-protocols|O2k-Protocols contents]][[Image:MiPNet10.05.jpg|centre|500px|thumb]]Respiratory oxygen flux: On-line display of oxygen concentration (blue) and oxygen flux (respiration, red). Endogenous respiration of endothelial cells leads to oxygen depletion, followed by reoxygenations (dotted arrows). Cell membrane permeabilization by digitonin causes a decline of respiration to the resting level (without adenylates in the medium, -ANP). ADP titration activates respiration about 2-fold above the endogenous level of oxygen consumption.Eye-fitted slopes of oxygen chart recorder traces belong to the past. With [[DatLab|DatLab]], trends are resolved. Accuracy is improved by standard numerical corrections. Graphs and protocols are stored and printed ready for publication.'''Reference'''[[Gnaiger_1993_Pure_Appl_Chem| Gnaiger E (1993) Nonequilibrium thermodynamics of energy transformations. Pure Appl Chem 65: 1983-2002.]]:>> O2k-Protocols:[[O2k-Protocols| Overall contents]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]]os O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Training course on high-resolution respirometry.''' Innsbruck, Tyrol, Austria; 2003 December 11-13. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop and training course on high-resolution respirometry.''' Schroecken, Vorarlberg, Austria; 2003 September 09-12. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on High-Resolution Respiro … '''O2k-Workshop on High-Resolution Respirometry - Introductory and Advanced.'''Schroecken, Voralberg, Austria; 2010 December 11 to 16.The past O2k-Workshop on HRR ('''IOC60''') was a success based on long-term experience combined with continuous improvements and innovations. With introductory and advanced groups working in parallel, the needs of the participants could be met more specifically compared to introductory and advanced workshops organized separately. The next O2k-Workshop, therefore, will again offer parallel introductory and advanced workpackages.:>> O2k-Workshop: [[Oroboros Events| Current dates]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on High-Resolution Respiro … '''O2k-Workshop on High-Resolution Respirometry - O2k-Basic and TPP-Basic.''' Schröcken, Vorarlberg, Austria; 2011 April 26 to May 1.[[File:O2k-TIP2k.jpg|right|200px|caption]]:>> O2k-Workshop: [[Oroboros Events| Current dates]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on High-Resolution Respirometry.''' Barcelona, Catalonia, Spain; 2012 May 29 to 30 :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on High-Resolution Respiro … '''O2k-Workshop on High-Resolution Respirometry: O2k-Basic and TPP-Basic.''' Schröcken, Vorarlberg, Austria; 2011 10 - 15 December :>> O2k-Workshop: [[Oroboros Events| Current dates]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on High-Resolution Respirometry: O2k-Basic.''' Schroecken, Vorarlberg, Austria 2012 December 05 to 10 :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on high-resolution respiro … '''O2k-Workshop on high-resolution respirometry and mitochondrial physiology.''' Seoul, Korea; 2007 February 4. Satellite to [[ASMRM]] 2007.:>> O2k-Workshop: [[Oroboros Events| Current dates]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on high-resolution respirometry.''' Innsbruck, Tyrol, Austria; 2001 October 04-05. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on high-resolution respirometry.''' Innsbruck, Tyrol, Austria; 2002 June 12-15. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on high-resolution respirometry.''' Sidney, Australia; 2012 April 02 to 04. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k-Workshop on high-resolution respirometry.''' Voralberg, Austria;2010 April 07 to 12. +
'''O2k-Workshop on high-resolution respirometry: O2k-Basic and TPP-Basic.''' Schroecken, Voralberg,Austria; 2012 April 11 to 16. :» O2k-Workshop: [[OROBOROS_Events|Current dates]] :» Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''O2k: Mitochondrial physiology (MiP) workshop on high-resolution respirometry.''' Schroecken AT, 27-31 March 2003. :>> O2k-Workshop: [[Oroboros Events| Current dates]] :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''OBJECTIVE''': Growing evidence suggests … '''OBJECTIVE''': Growing evidence suggests that mitochondria function is impaired in sepsis. Here, we tested the hypothesis that lipopolysaccharide would induce mitochondrial Ca2+ overload and oxygen utilization abnormalities as consequences of sarcoplasmic reticulum Ca2+ handling derangements that are typically observed in sepsis. As lipopolysaccharide-induced sarcoplasmic reticulum dysfunction was mainly characterized by reduced sarcoplasmic reticulum Ca2+ uptake and Ca2+ leak, we tested whether dantrolene, a sarco(endo)plasmic reticulum calcium ATPase leak inhibitor, would prevent mitochondrial and cardiac contractile dysfunction.'''DESIGN''': Randomized controlled trial.'''SETTING''': Experimental laboratory.'''SUBJECTS''': Male Sprague Dawley rats.'''INTERVENTIONS''': Sepsis was induced by injection of endotoxin lipopolysaccharide (10 mg/kg/intravenously). Assessment of contractile function and Ca2+ handling was performed 4 hr after lipopolysaccharide. The relative contribution of the different Ca2+ transporters to relaxation in intact cardiomyocytes was studied during successive electrically evoked twitches and caffeine stimulation. Sarcoplasmic reticulum vesicles and mitochondria from ventricles of rats treated or not with lipopolysaccharide were prepared to evaluate Ca2+ uptake-release and oxygen fluxes, respectively. Effects of dantrolene (10 mg/kg) treatment in rats were evaluated in sarcoplasmic reticulum vesicles, mitochondria, and isolated hearts.'''MEASUREMENTS AND MAIN RESULTS''': Lipopolysaccharide challenge elicited cardiac contractile dysfunction that was accompanied by severe derangements in sarcoplasmic reticulum function, i.e., reduced Ca2+ uptake and increased sarcoplasmic reticulum Ca2+ leak. Functional sarcoplasmic reticulum changes were associated with modification in the status of phospholamban phosphorylation whereas SERCA was unchanged. Rises in mitochondrial Ca2+ content observed in lipopolysaccharide-treated rats coincided with derangements in mitochondrial oxygen efficacy, i.e., reduced respiratory control ratio. Administration of dantrolene in lipopolysaccharide-treated rats prevented mitochondrial Ca2+ overload and mitochondrial oxygen utilization abnormalities. Moreover, dantrolene treatment in lipopolysaccharide rats improved heart mitochondrial redox state and myocardial dysfunction.'''CONCLUSION:''' These experiments suggest that sarcoplasmic reticulum Ca2+ handling dysfunction is an early event during endotoxemia that could be responsible for, or contribute to, mitochondrial Ca2+ overload, metabolic failure, and cardiac dysfunction.tion is an early event during endotoxemia that could be responsible for, or contribute to, mitochondrial Ca2+ overload, metabolic failure, and cardiac dysfunction. +
'''OBJECTIVE:''' Impairments in mitochondr … '''OBJECTIVE:''' Impairments in mitochondrial function have been proposed to play a role in the etiology of diabetic sensory neuropathy. We tested the hypothesis that mitochondrial dysfunction in axons of sensory neurons in type 1 diabetes is due to abnormal activity of the respiratory chain and an altered mitochondrial proteome.'''RESEARCH DESIGN AND METHODS:''' Proteomic analysis using stable isotope labeling with amino acids in cell culture (SILAC) determined expression of proteins in mitochondria from dorsal root ganglia (DRG) of control, 22-week-old streptozotocin (STZ)-diabetic rats, and diabetic rats treated with insulin. Rates of oxygen consumption and complex activities in mitochondria from DRG were measured. Fluorescence imaging of axons of cultured sensory neurons determined the effect of diabetes on mitochondrial polarization status, oxidative stress, and mitochondrial matrix-specific reactive oxygen species (ROS).'''RESULTS:''' Proteins associated with mitochondrial dysfunction, oxidative phosphorylation, ubiquinone biosynthesis, and the citric acid cycle were downregulated in diabetic samples. For example, cytochrome c oxidase subunit IV (COX IV; a Complex IV protein) and NADH dehydrogenase Fe-S protein 3 (NDUFS3; a Complex I protein) were reduced by 29 and 36% (''P'' < 0.05), respectively, in diabetes and confirmed previous Western blot studies. Respiration and mitochondrial complex activity was significantly decreased by 15 to 32% compared with control. The axons of diabetic neurons exhibited oxidative stress and depolarized mitochondria, an aberrant adaption to oligomycin-induced mitochondrial membrane hyperpolarization, but reduced levels of intramitochondrial superoxide compared with control.'''CONCLUSIONS:''' Abnormal mitochondrial function correlated with a downregulation of mitochondrial proteins, with components of the respiratory chain targeted in lumbar DRG in diabetes. The reduced activity of the [[respiratory chain]] was associated with diminished superoxide generation within the mitochondrial matrix and did not contribute to oxidative stress in axons of diabetic neurons. Alternative pathways involving polyol pathway activity appear to contribute to raised ROS in axons of diabetic neurons under high glucose concentration.tic neurons under high glucose concentration. +
'''OBJECTIVE:''' Increasing evidence point … '''OBJECTIVE:''' Increasing evidence points to the role of mitochondrial dysfunction in the pathogenesis of sepsis. Previous data indicate that mitochondrial function is affected in monocytes from septic patients, but the underlying mechanisms and the impact of these changes on the patients' outcome are unknown. We aimed to determine the mechanisms involved in mitochondrial dysfunction in peripheral blood mononuclear cells from patients with septic shock.'''DESIGN:''' A cohort of patients with septic shock to study peripheral blood mononuclear cell mitochondrial respiration by high-resolution respirometry analyses and to compare with cells from control subjects.'''SETTING:''' Three intensive care units and an academic research laboratory.'''SUBJECTS:''' Twenty patients with septic shock and a control group composed of 18 postoperative patients without sepsis or shock.'''INTERVENTIONS:''' Ex vivo measurements of mitochondrial oxygen consumption were carried out in digitonin-permeabilized peripheral blood mononuclear cells from 20 patients with septic shock taken during the first 48 h after intensive care unit admission as well as in peripheral blood mononuclear cells from control subjects. Clinical parameters such as hospital outcome and sepsis severity were also analyzed and the relationship between these parameters and the oxygen consumption pattern was investigated.'''MEASUREMENTS AND MAIN RESULTS:''' We observed a significant reduction in the respiration specifically associated with adenosine-5'-triphosphate synthesis ([[State 3]]) compared with the control group (5.60 vs. 9.89 nmol O2/min/10(7) cells, respectively, ''P'' < .01). Reduction of State 3 respiration in patients with septic shock was seen with increased prevalence of organ failure (''r'' = -0.46, ''P'' = .005). Nonsurviving patients with septic shock presented significantly lower adenosine diphosphate-stimulated respiration when compared with the control group (4.56 vs. 10.27 nmol O2/min/10(7) cells, respectively; ''P'' = .004). Finally, the presence of the functional F1Fo adenosine-5'-triphosphate synthase complex (0.51 vs. 1.00 ng oligo/mL/10(6) cells, ''P'' = .02), but not the adenine nucleotide translocator, was significantly lower in patients with septic shock compared with control cells.'''CONCLUSION:''' Mitochondrial dysfunction is present in immune cells from patients with septic shock and is characterized as a reduced respiration associated to adenosine-5'-triphosphate synthesis. The molecular basis of this phenotype involve a reduction of F1Fo adenosine-5'-triphosphate synthase activity, which may contribute to the energetic failure found in sepsis.ute to the energetic failure found in sepsis. +
'''OBJECTIVE:''' To determine biological m … '''OBJECTIVE:''' To determine biological mechanisms involved in posttransplantation diabetes mellitus caused by the immunosuppressant tacrolimus (FK506).'''METHODS:''' INS-1 cells and isolated rat islets were incubated with vehicle or FK506 and harvested at 24-hr intervals. Cells were assessed for viability, apoptosis, proliferation, cell insulin secretion, and content. Gene expression studies by microarray analysis, quantitative polymerase chain reaction, and motifADE analysis of the microarray data identified potential FK506-mediated pathways and regulatory motifs. Mitochondrial functions, including cell respiration, mitochondrial content, and bioenergetics were assessed.'''RESULTS:''' Cell replication, viability, insulin secretion, oxygen consumption, and mitochondrial content were decreased (''P''<0.05) 1.2-, 1.27-, 1.77-, 1.32-, and 1.43-fold, respectively, after 48-hr FK506 treatment. Differences increased with time. FK506 (50 ng/mL) and cyclosporine A (800 ng/mL) had comparable effects. FK506 significantly decreased mitochondrial content and mitochondrial bioenergetics and showed a trend toward decreased oxygen consumption in isolated islets. Cell apoptosis and proliferation, mitochondrial DNA copy number, and ATP:ADP ratios were not significantly affected. Pathway analysis of microarray data showed FK506 modification of pathways involving ATP metabolism, membrane trafficking, and cytoskeleton remodeling. PGC1-α mRNA was down-regulated by FK506. MotifADE identified nuclear factor of activated T-cells, an important mediator of β-cell survival and function, as a potential factor mediating both up- and down-regulation of gene expression.'''CONCLUSIONS:''' At pharmacologically relevant concentrations, FK506 decreases insulin secretion and reduces mitochondrial density and function without changing apoptosis rates, suggesting that posttransplantation diabetes induced by FK506 may be mediated by its effects on mitochondrial function.ted by its effects on mitochondrial function. +
'''Objective''': Impairments in mitochondr … '''Objective''': Impairments in mitochondrial physiology may play a role in diabetic sensory neuropathy. We tested the hypothesis that mitochondrial dysfunction in sensory neurons is due to abnormal mitochondrial respiratory function.'''Research design and methods''': Rates of oxygen consumption were measured in mitochondria from dorsal root ganglia (DRG) of 12- to- 22-week streptozotocin (STZ)-induced diabetic rats, diabetic rats treated with insulin, and age-matched controls. Activities and expression of components of mitochondrial complexes and reactive oxygen species (ROS) were analyzed.'''Results''': Rates of coupled respiration with pyruvate + malate (P + M) and with ascorbate + TMPD (Asc + TMPD) in DRG were unchanged after 12 weeks of diabetes. By 22 weeks of diabetes, respiration with P + M was significantly decreased by 31-44% and with Asc + TMPD by 29-39% compared with control. Attenuated mitochondrial respiratory activity of STZ-diabetic rats was significantly improved by insulin that did not correct other indices of diabetes. Activities of mitochondrial complexes I and IV and the Krebs cycle enzyme, citrate synthase, were decreased in mitochondria from DRG of 22-week STZ-diabetic rats compared with control. ROS levels in perikarya of DRG neurons were not altered by diabetes, but ROS generation from mitochondria treated with antimycin A was diminished compared with control. Reduced mitochondrial respiratory function was associated with downregulation of expression of mitochondrial proteins.'''Conclusions''': Mitochondrial dysfunction in sensory neurons from type 1 diabetic rats is associated with impaired rates of respiratory activity and occurs without a significant rise in perikaryal ROS.hout a significant rise in perikaryal ROS. +
'''Objective'''—The enzyme telomerase and … '''Objective'''—The enzyme telomerase and its catalytic subunit the telomerase reverse transcriptase (TERT) are important for maintenance of telomere length in the nucleus. Recent studies provided evidence for a mitochondrial localization of TERT. Therefore, we investigated the exact localization of TERT within the mitochondria and its function.'''Methods and Results'''—Here, we demonstrate that TERT is localized in the matrix of the mitochondria. TERT binds to mitochondrial DNA at the coding regions for ND1 and ND2. Binding of TERT to mitochondrial DNA protects against ethidium bromide–induced damage. TERT increases overall respiratory chain activity, which is most pronounced at Complex I and dependent on the reverse transcriptase activity of the enzyme. Moreover, mitochondrial reactive oxygen species are increased after genetic ablation of TERT by shRNA. Mitochondrially targeted TERT and not wild-type TERT revealed the most prominent protective effect on H2O2-induced apoptosis. Lung fibroblasts from 6-month-old TERT-/- mice (F2 generation) showed increased sensitivity toward UVB radiation and heart mitochondria exhibited significantly reduced respiratory chain activity already under basal conditions, demonstrating the protective function of TERT ''in vivo''.'''Conclusion'''—Mitochondrial TERT exerts a novel protective function by binding to mitochondrial DNA, increasing respiratory chain activity and protecting against oxidative stress–induced damage.iratory chain activity and protecting against oxidative stress–induced damage. +
'''Oroboros O2k-Workshop on High-Resolution Respirometry. Obergurgl, Tyrol, Austria; 2010 October 01 to 06. Satellite to [[MiP2010]].''' :>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]] +
'''Oroboros O2k-Workshop on high-resolutio … '''Oroboros O2k-Workshop on high-resolution respirometry'''. Schroecken, Austria (2022 October 03-08). Following the [[MiPNet27.05_Schroecken_BEC_tutorial-Living_Communications_pmP|BEC tutorial on mitochondrial membrane potential and protonmotive pressure]] (2022 Sep 30 - Oct 03).[[MiPNet27.05_Schroecken_BEC_tutorial-Living_Communications_pmP|BEC tutorial on mitochondrial membrane potential and protonmotive pressure]] (2022 Sep 30 - Oct 03). +
'''Oroboros O2k-Workshop on high-resolution respirometry'''. Schroecken, Austria (2023 June 19-24). +
'''Oroboros O2k-Workshop on high-resolution respirometry'''. Schroecken, Austria (2023 October 02-07). +
'''Oroboros O2k-Workshop on high-resolution respirometry'''. Schroecken, Austria (2024 June 17-22). +
'''Oroboros O2k-Workshop on high-resolution respirometry'''. Schroecken, Austria (2024 Sep 30 - Oct 05). +
'''Oroboros O2k-Workshop on high-resolution respirometry'''. Schroecken, Austria; 2019 September. +
'''Oroboros O2k-Workshop on high-resolution respirometry'''. Schroecken, Austria; 2019. +
'''Oroboros Virtual O2k-Workshop on high-resolution respirometry and PhotoBiology'''. +
'''Oroboros Virtual O2k-Workshop on high-resolution respirometry and and measurement of the redox state of the Q-pool'''. +
'''Oroboros Virtual O2k-Workshops on high-resolution respirometry''' were offered during the COVID-19 lockdown and are discontinued. +
'''Pesta D, Gnaiger E (2015) Preparation o … '''Pesta D, Gnaiger E (2015) Preparation of permeabilized muscle fibers for diagnosis of mitochondrial respiratory function. Mitochondr Physiol Network 14.14(02):1-5.''' Application of [[permeabilized muscle fibers]] and [[high-resolution respirometry]] offer a sensitive diagnostic test of mitochondrial dysfunction in small [[biopsy]] specimens of human muscle. By using these techniques in conjunction with multiple [[substrate-uncoupler-inhibitor titration]] (SUIT) protocols, respirometric studies of human and animal tissue biopsies improve our fundamental understanding of mitochondrial respiratory control and the pathophysiology of mitochondrial myopathies.[[Image:MiPNet14.14.jpg|right|200px|thumb]]:>> Product: [[O2k-Catalogue: O2k-MultiSensor]], [[O2k-Core]], [[Oroboros O2k-Catalogue]][[Oroboros O2k-Catalogue]] +
'''Protocol''': Couple palmitoylcarnitine (10µM) + malate (1mM) on isolated mitochondria and permeabilized fibers. In such case the buffer is always supplemented with 2mg/ml of BSA. +
'''Protocol''': I use either palmitoyl-L-carnitine plus malate (25 µM + 2.5 mM) or palmitoyl-CoA + L-carnitine + malate (25 µM + 2 mM + 2.5 mM) as substrates. Respiratory control index is usually around 5-6 for healthy controls. +
'''Protocol''': Palmitate, Stearate, Oleate and Linoleate in intact cells. We use various BSA-fatty acid combinations that result in free fatty acid levels that are in the 2 to 12 nM range. +
'''Protocol''': final concentration of dig … '''Protocol''': final concentration of digitonin in chamber is 10μg/mlcell number in chamber is 2 millions cell/ml, cell type PBMC, Malate (2mM), Palmitoyl-DLcarnitine-HCl (20μM), ADP (2.5mM), pyruvate (5mM), glutamate (10mM), succinate (10mM), rotenone (0.1μM), malonic acid(5mM), myxothiazol (0.5μM), antimycin A (2.5μM), TMPD (0.5mM), azide (100mM)cin A (2.5μM), TMPD (0.5mM), azide (100mM) +
'''Purpose of review''': Mitochondrial con … '''Purpose of review''': Mitochondrial content and function vary across species, tissue types, and lifespan. Alterations in skeletal muscle mitochondrial function have been reported to occur in in aging and in many other pathological conditions. This review focuses on the state of the art ''in vivo'' and ''in vitro'' methodologies for assessment of muscle mitochondrial function.'''Recent findings''': Classic studies of isolated mitochondria have measured function from maximal respiratory capacity. These fundamental methods have recently been substantially improved and novel approaches to asses mitochondrial functions ''in vitro'' have been emerged. Noninvasivemethods based on magnetic resonance spectroscopy (MRS) and near-infraredspectroscopy (NIRS) permit ''in vivo'' assessment of mitochondrial function and are rapidly becoming more accessible to many investigators. Moreover, it is now possible to gather information on regulation of mitochondrial content by measuring the ''in vivo'' synthesis rate of individual mitochondrial proteins.'''Summary: High-resolution respirometry has emerged as a powerful tool for ''in vitro'' measurements of mitochondrial function in isolated mitochondria and permeabilized fibers.''' Direct measurements of ATP production are possible by bioluminescence. Mechanistic data provided by these methods is further complimented by ''in vivo'' assessment using MRS and NIRS and the translational rate of gene transcripts.he translational rate of gene transcripts. +
'''REASONS FOR PERFORMING STUDY:''' Limite … '''REASONS FOR PERFORMING STUDY:''' Limited information exists about the muscle mitochondrial respiratory function changes that occur in horses during an endurance season.'''OBJECTIVES:''' To determine effects of training and racing on muscle oxidative phosphorylation (OXPHOS) and electron transport system (ET-pathway) capacities in horses with high resolution respirometry (HRR).'''METHODS:''' Mitochondrial respiration was measured in microbiopsies taken from the triceps brachii (tb) and gluteus medius (gm) muscles in 8 endurance horses (7 purebred Arabians and 1 crossbred Arabian) before training (T0), after two 10 week training periods (T1, T2) and after 2 CEI** endurance races (R1, R2). Muscle OXPHOS capacity was determined using 2 titration protocols without (SUIT 1) or with pyruvate (SUIT 2) as substrate. Electrons enter at the level of Complex I, Complex II or both complexes simultaneously (Complexes I+II). Muscle ET capacity was obtained by uncoupling Complexes I+II sustained respiration.'''RESULTS:''' T1 improved OXPHOS and ET capacities in the tb as demonstrated by the significant increase of oxygen fluxes vs. T0 (Complex I: +67%; ET-pathway: +37%). Training improved only OXPHOS in the gm (Complex I: +34%). Among horses that completed the race, a significant decrease in OXPHOS (Complex I: ∼ -35%) and ET-pathway (-22%) capacities was found in the tb with SUIT 2 indicating a reduced aerobic glycolysis. Significant correlations between CK activities and changes in OXPHOS were found suggesting a relationship between exercise-induced muscle damage and depression of mitochondrial respiration.'''CONCLUSIONS:''' For the first time, OXPHOS and ET capacities in equine muscle at different steps of an endurance season have been determined by HRR. Significant alterations in mitochondrial respiratory function in response to endurance training and endurance racing have been observed although these changes appeared to be muscle group specific.nges appeared to be muscle group specific. +
'''Reck M, Wyss M, Lassnig B, Gnaiger E (1 … '''Reck M, Wyss M, Lassnig B, Gnaiger E (1997) DatLab 2. High time resolution. Mitochondr Physiol Network 02.04:1-11.''' »[http://www.bioblast.at/index.php/File:MiPNet02.04_DatLab2_TimeConstant.pdf Versions]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue ]][Oroboros O2k-Catalogue ]] +