title: NOS isoform-specific regulation of basal but not exercise-induced mitochondrial biogenesis in mouse skeletal muscle.
abstract: Nitric oxide is a potential regulator of mitochondrial biogenesis. Therefore, we investigated if mice deficient in endothelial nitric oxide synthase (eNOS-/-) or neuronal NOS (nNOS-/-) have attenuated activation of skeletal muscle mitochondrial biogenesis in response to exercise. eNOS-/-, nNOS-/- and C57Bl/6 (CON) mice (16.3 +/- 0.2 weeks old) either remained in their cages (basal) or ran on a treadmill (16 m min(-1), 5% grade) for 60 min (n = 8 per group) and were killed 6 h after exercise. Other eNOS-/-, nNOS-/- and CON mice exercise trained for 9 days (60 min per day) and were killed 24 h after the last bout of exercise training. eNOS-/- mice had significantly higher nNOS protein and nNOS-/- mice had significantly higher eNOS protein in the EDL, but not the soleus. The basal mitochondrial biogenesis markers NRF1, NRF2alpha and mtTFA mRNA were significantly (P< 0.05) higher in the soleus and EDL of nNOS-/- mice whilst basal citrate synthase activity was higher in the soleus and basal PGC-1alpha mRNA higher in the EDL. Also, eNOS-/- mice had significantly higher basal citrate synthase activity in the soleus but not the EDL. Acute exercise increased (P< 0.05) PGC-1alpha mRNA in soleus and EDL and NRF2alpha mRNA in the EDL to a similar extent in all genotypes. In addition, short-term exercise training significantly increased cytochrome c protein in all genotypes (P< 0.05) in the EDL. In conclusion, eNOS and nNOS are differentially involved in the basal regulation of mitochondrial biogenesis in skeletal muscle but are not critical for exercise-induced increases in mitochondrial biogenesis in skeletal muscle.
authors.affiliation: Department of Physiology, University of Melbourne, Parkville, Victoria, 3010, Australia. gdwadley@unimelb.edu.au
authors.forename: G D
authors.initials: GD
authors.lastname: Wadley
authors.forename: J
authors.initials: J
authors.lastname: Choate
authors.forename: G K
authors.initials: GK
authors.lastname: McConell
mesh_terms: D055372:AMP-Activated Protein Kinases; D000818:Animals; D002950:Citrate (si)-Synthase / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008931:Mitochondria, Muscle / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism*; D051266:Nuclear Respiratory Factor 1 / Q000378:metabolism; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010805:Physical Conditioning, Animal / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D009097:Multienzyme Complexes; C495634:Nrf1 protein, mouse; D051266:Nuclear Respiratory Factor 1; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; D002950:Citrate (si)-Synthase; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D055372:AMP-Activated Protein Kinases