Difference between revisions of "Holloway 2012 Abstract Bioblast"
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|abstract=The role of mitofusin-2 (MFN-2) in regulating mitochondrial dynamics has been well-characterized in lower order eukaryotic cell lines through the complete ablation of MFN-2 protein. However, to support the contractile function of mature skeletal muscle, the subcellular architecture and constituent proteins of this tissue differ substantially from simpler cellular organisms. Such differences may also impact the role of MFN-2 in mature mammalian muscle, and it is unclear if minor fluctuations in MFN-2 - as observed in response to physiological perturbations - have a functional consequence. Therefore, we have transiently transfected MFN-2 cDNA into rat tibialis anterior muscle to determine the effect of physiolgically relevant increases in MFN-2 protein on mitochondrial bioenergetics. Permeabilized muscle fibres generated from muscle following MFN-2-transfection were used for functional assessments of mitochondrial bioenergetics. In addition, we have further established a novel method for selecting fibre bundles from this region that are positively transfected, and using this approach transient transfection increased MFN-2 protein ~2.3 fold in selected muscle fibres. However, this did not alter maximal rates of oxygen consumption or the sensitivity for ADP-stimulated respiration. In addition, MFN-2 over-expression did not alter rates of H<sub>2</sub>O2 emission. Altogether, and contrary to evidence from lower order eukaryotic cells, our results indicate that over-expressing MFN-2 in healthy muscle does not influence mitochondrial bioenergetics in mature mammalian skeletal muscle. | |abstract=The role of mitofusin-2 (MFN-2) in regulating mitochondrial dynamics has been well-characterized in lower order eukaryotic cell lines through the complete ablation of MFN-2 protein. However, to support the contractile function of mature skeletal muscle, the subcellular architecture and constituent proteins of this tissue differ substantially from simpler cellular organisms. Such differences may also impact the role of MFN-2 in mature mammalian muscle, and it is unclear if minor fluctuations in MFN-2 - as observed in response to physiological perturbations - have a functional consequence. Therefore, we have transiently transfected MFN-2 cDNA into rat tibialis anterior muscle to determine the effect of physiolgically relevant increases in MFN-2 protein on mitochondrial bioenergetics. Permeabilized muscle fibres generated from muscle following MFN-2-transfection were used for functional assessments of mitochondrial bioenergetics. In addition, we have further established a novel method for selecting fibre bundles from this region that are positively transfected, and using this approach transient transfection increased MFN-2 protein ~2.3 fold in selected muscle fibres. However, this did not alter maximal rates of oxygen consumption or the sensitivity for ADP-stimulated respiration. In addition, MFN-2 over-expression did not alter rates of H<sub>2</sub>O2 emission. Altogether, and contrary to evidence from lower order eukaryotic cells, our results indicate that over-expressing MFN-2 in healthy muscle does not influence mitochondrial bioenergetics in mature mammalian skeletal muscle. | ||
* [http://www.ncbi.nlm.nih.gov/pubmed/20403324 Chen H, Vermulst M, Wang YE, Chomyn A, Prolla TA, McCaffery JM, Chan DC (2010) Mitochondrial fusion is required for mtDNA stability in skeletal muscle and tolerance of mtDNA mutations. Cell 141: 280-289 Open Access] | |||
* [http://www.ncbi.nlm.nih.gov/pubmed/22777004 Chen Y, Csordas G, Jowdy C, Schneider TG, Csordas N, Wang W, Liu Y, Kohlhaas M, Meiser M, Bergem S, Nerbonne JM, Dorn GW 2nd, Maack C (2012) Mitofusin 2-containing mitochondrial-reticular microdomains direct rapid cardiomyocyte bioenergetic responses via interorganelle Ca(2+) crosstalk. Circ Res 111: 863-875] | |||
|keywords=Mitofusin-2, | |keywords=Mitofusin-2, | ||
|mipnetlab=CA Guelph Holloway GP | |mipnetlab=CA Guelph Holloway GP | ||
Revision as of 17:04, 23 November 2012
| Holloway GP (2012) Over-expressing mitofusin-2 in healthy mature mammalian skeletal muscle does not alter mitochondrial bioenergetics. Mitochondr Physiol Network 17.12. |
Link: MiPNet17.12 Bioblast 2012 - Open Access
Holloway GP (2012)
Event: Bioblast 2012
The role of mitofusin-2 (MFN-2) in regulating mitochondrial dynamics has been well-characterized in lower order eukaryotic cell lines through the complete ablation of MFN-2 protein. However, to support the contractile function of mature skeletal muscle, the subcellular architecture and constituent proteins of this tissue differ substantially from simpler cellular organisms. Such differences may also impact the role of MFN-2 in mature mammalian muscle, and it is unclear if minor fluctuations in MFN-2 - as observed in response to physiological perturbations - have a functional consequence. Therefore, we have transiently transfected MFN-2 cDNA into rat tibialis anterior muscle to determine the effect of physiolgically relevant increases in MFN-2 protein on mitochondrial bioenergetics. Permeabilized muscle fibres generated from muscle following MFN-2-transfection were used for functional assessments of mitochondrial bioenergetics. In addition, we have further established a novel method for selecting fibre bundles from this region that are positively transfected, and using this approach transient transfection increased MFN-2 protein ~2.3 fold in selected muscle fibres. However, this did not alter maximal rates of oxygen consumption or the sensitivity for ADP-stimulated respiration. In addition, MFN-2 over-expression did not alter rates of H2O2 emission. Altogether, and contrary to evidence from lower order eukaryotic cells, our results indicate that over-expressing MFN-2 in healthy muscle does not influence mitochondrial bioenergetics in mature mammalian skeletal muscle.
• Keywords: Mitofusin-2
• O2k-Network Lab: CA Guelph Holloway GP
Labels:
Stress:Genetic Defect; Knockdown; Overexpression"Genetic Defect; Knockdown; Overexpression" 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: Rat Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue
Regulation: ATP; ADP; AMP; PCr"ATP; ADP; AMP; PCr" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property.
HRR: Oxygraph-2k
Affiliations and author contributions
Dept. Human Health and Nutritional Sciences, University of Guelph, Canada; Email: ghollowa@uoguelph.ca
