Difference between revisions of "Tretter 2012 Free Radic Biol Med"
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|year=2012 | |year=2012 | ||
|journal=Free Radic Biol Med | |journal=Free Radic Biol Med | ||
|abstract=H<sub>2</sub>O<sub>2</sub> generation associated with α-glycerophosphate (α-GP) oxidation was addressed in guinea pig brain mitochondria challenged with high Ca<sup>2+</sup> load (10 μM). Exposure to 10 μM Ca<sup>2+</sup> induced an abrupt 2.5-fold increase in H<sub>2</sub>O<sub>2</sub> release compared to that measured in the presence of a physiological cytosolic Ca<sup>2+</sup> concentration (100 nM) from mitochondria respiring on 5 mM α-GP in the presence of ADP (2 mM). The Ca<sup>2+</sup>-induced stimulation of H<sub>2</sub>O<sub>2</sub> generation was reversible and unaltered by the uniporter blocker Ru 360, indicating that it did not require Ca<sup>2+</sup> uptake into mitochondria. Enhanced H<sub>2</sub>O<sub>2</sub> generation by Ca<sup>2+</sup> was also observed in the absence of ADP when mitochondria exhibited permeability transition pore opening with a decrease in the NAD(P)H level, dissipation of membrane potential, and mitochondrial swelling. Furthermore, mitochondria treated with the pore-forming peptide alamethicin also responded with an elevated H<sub>2</sub>O<sub>2</sub> generation to a challenge with 10 μM Ca<sup>2+</sup>. Ca<sup>2+</sup>-induced promotion of H<sub>2</sub>O<sub>2</sub> formation was further enhanced by the Complex III inhibitor myxothiazol. With 20 mM α-GP concentration, stimulation of H<sub>2</sub>O<sub>2</sub> formation by Ca<sup>2+</sup> was detected only in the presence, not in the absence, of ADP. It is concluded that α-glycerophosphate dehydrogenase, which is accessible to and could be activated by a rise in the level of cytosolic Ca<sup>2+</sup>, makes a major contribution to Ca<sup>2+</sup>-stimulated H<sub>2</sub>O<sub>2</sub> generation. This work highlights a unique high-Ca<sup>2+</sup>-stimulated reactive oxygen species-forming mechanism in association with oxidation of α-GP, which is largely independent of the bioenergetic state and can proceed even in damaged, functionally incompetent mitochondria. | |abstract=H<sub>2</sub>O<sub>2</sub> generation associated with α-glycerophosphate (α-GP) oxidation was addressed in guinea pig brain mitochondria challenged with high Ca<sup>2+</sup> load (10 μM). Exposure to 10 μM Ca<sup>2+</sup> induced an abrupt 2.5-fold increase in H<sub>2</sub>O<sub>2</sub> release compared to that measured in the presence of a physiological cytosolic Ca<sup>2+</sup> concentration (100 nM) from mitochondria respiring on 5 mM α-GP in the presence of ADP (2 mM). The Ca<sup>2+</sup>-induced stimulation of H<sub>2</sub>O<sub>2</sub> generation was reversible and unaltered by the uniporter blocker Ru 360, indicating that it did not require Ca<sup>2+</sup> uptake into mitochondria. Enhanced H<sub>2</sub>O<sub>2</sub> generation by Ca<sup>2+</sup> was also observed in the absence of ADP when mitochondria exhibited permeability transition pore opening with a decrease in the NAD(P)H level, dissipation of membrane potential, and mitochondrial swelling. Furthermore, mitochondria treated with the pore-forming peptide alamethicin also responded with an elevated H<sub>2</sub>O<sub>2</sub> generation to a challenge with 10 μM Ca<sup>2+</sup>. Ca<sup>2+</sup>-induced promotion of H<sub>2</sub>O<sub>2</sub> formation was further enhanced by the Complex III inhibitor myxothiazol. With 20 mM α-GP concentration, stimulation of H<sub>2</sub>O<sub>2</sub> formation by Ca<sup>2+</sup> was detected only in the presence, not in the absence, of ADP. It is concluded that [[Glycerophosphate dehydrogenase complex |α-glycerophosphate dehydrogenase]], which is accessible to and could be activated by a rise in the level of cytosolic Ca<sup>2+</sup>, makes a major contribution to Ca<sup>2+</sup>-stimulated H<sub>2</sub>O<sub>2</sub> generation. This work highlights a unique high-Ca<sup>2+</sup>-stimulated reactive oxygen species-forming mechanism in association with oxidation of α-GP, which is largely independent of the bioenergetic state and can proceed even in damaged, functionally incompetent mitochondria. | ||
|keywords=Mitochondria; Reactive oxygen species; Calcium; Hydrogen peroxide; α-Glycerophosphate dehydrogenase; Reverse electron transport; Permeability transition pore; Myxothiazol; α-Glycerophosphate shuttle; Free radicals | |keywords=Mitochondria; Reactive oxygen species; Calcium; Hydrogen peroxide; α-Glycerophosphate dehydrogenase; Reverse electron transport; Permeability transition pore; Myxothiazol; α-Glycerophosphate shuttle; Free radicals | ||
|mipnetlab=HU_Budapest_Tretter L | |mipnetlab=HU_Budapest_Tretter L | ||
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|tissues=Nervous system | |tissues=Nervous system | ||
|preparations=Isolated Mitochondria | |preparations=Isolated Mitochondria | ||
|injuries=RONS; Oxidative Stress | |injuries=RONS; Oxidative Stress | ||
|substratestates=GpDH | |substratestates=GpDH |
Revision as of 09:51, 14 December 2014
Tretter L, Adam-Vizi V (2012) High Ca2+ load promotes hydrogen peroxide generation via activation of α-glycerophosphate dehydrogenase in brain mitochondria. Free Radic Biol Med 53:2119-30. |
Tretter L, Adam-Vizi V (2012) Free Radic Biol Med
Abstract: H2O2 generation associated with α-glycerophosphate (α-GP) oxidation was addressed in guinea pig brain mitochondria challenged with high Ca2+ load (10 μM). Exposure to 10 μM Ca2+ induced an abrupt 2.5-fold increase in H2O2 release compared to that measured in the presence of a physiological cytosolic Ca2+ concentration (100 nM) from mitochondria respiring on 5 mM α-GP in the presence of ADP (2 mM). The Ca2+-induced stimulation of H2O2 generation was reversible and unaltered by the uniporter blocker Ru 360, indicating that it did not require Ca2+ uptake into mitochondria. Enhanced H2O2 generation by Ca2+ was also observed in the absence of ADP when mitochondria exhibited permeability transition pore opening with a decrease in the NAD(P)H level, dissipation of membrane potential, and mitochondrial swelling. Furthermore, mitochondria treated with the pore-forming peptide alamethicin also responded with an elevated H2O2 generation to a challenge with 10 μM Ca2+. Ca2+-induced promotion of H2O2 formation was further enhanced by the Complex III inhibitor myxothiazol. With 20 mM α-GP concentration, stimulation of H2O2 formation by Ca2+ was detected only in the presence, not in the absence, of ADP. It is concluded that α-glycerophosphate dehydrogenase, which is accessible to and could be activated by a rise in the level of cytosolic Ca2+, makes a major contribution to Ca2+-stimulated H2O2 generation. This work highlights a unique high-Ca2+-stimulated reactive oxygen species-forming mechanism in association with oxidation of α-GP, which is largely independent of the bioenergetic state and can proceed even in damaged, functionally incompetent mitochondria. • Keywords: Mitochondria; Reactive oxygen species; Calcium; Hydrogen peroxide; α-Glycerophosphate dehydrogenase; Reverse electron transport; Permeability transition pore; Myxothiazol; α-Glycerophosphate shuttle; Free radicals
• O2k-Network Lab: HU_Budapest_Tretter L
Labels: MiParea: Respiration
Stress:RONS; Oxidative Stress"RONS; Oxidative Stress" is not in the list (Cell death, Cryopreservation, Ischemia-reperfusion, Permeability transition, Oxidative stress;RONS, Temperature, Hypoxia, Mitochondrial disease) of allowed values for the "Stress" property. Organism: Guinea pig Tissue;cell: Nervous system Preparation: Isolated Mitochondria"Isolated Mitochondria" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property.
HRR: Oxygraph-2k
Fura-6F; Amplex Red; Safranin