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Pyruvate suppresses PGC1alpha expression and substrate utilization despite increased respiratory chain content in C2C12 myotubes
journal contribution
posted on 2010-08-01, 00:00 authored by Andrew Philp, Joaquin Perez-Schindler, Charlotte Green, Lee HamiltonLee Hamilton, Keith BaarSodium pyruvate can increase mitochondrial biogenesis in C2C12 myoblasts in a peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC1alpha)-independent manner. The present study examined the effect of 72-h treatment with sodium pyruvate (5-50 mM) or sodium chloride (50 mM) as an osmotic control on the regulation of mitochondrial substrate metabolism and biogenesis in C2C12 myotubes. Pyruvate (50 mM) increased the levels of fatty acid oxidation enzymes (CD36, 61%, and beta-oxidative enzyme 3-hydroxyacyl-CoA dehydrogenase, 54%) and the expression of cytochrome-c oxidase subunit I (220%) and cytochrome c (228%), consistent with its previous described role as a promoter of mitochondrial biogenesis. However, in contrast, pyruvate treatment reduced glucose transporter 4 (42%), phosphofructokinase (57%), and PGC1alpha (72%) protein content as well as PGC1alpha (48%) and PGC1beta (122%) mRNA. The decrease in PGC1alpha was compensated for by an increase in the PGC1alpha-related coactivator (PRC; 187%). Pyruvate treatment reduced basal and insulin-stimulated glucose uptake (41% and 31%, respectively) and palmitate uptake and oxidation (24% and 31%, respectively). The addition of the pyruvate dehydrogenase activator dichloroacetate (DCA) and the TCA precursor glutamine increased PGC1alpha expression (368%) and returned PRC expression to basal. Glucose uptake increased by 4.2-fold with DCA and glutamine and palmitate uptake increased by 18%. Coupled to this adaptation was an 80% increase in oxygen consumption. The data suggest that supraphysiological doses of pyruvate decrease mitochondrial function despite limited biogenesis and that anaplerotic agents can reverse this effect.
History
Journal
American journal of physiology. Cell physiologyVolume
299Issue
2Pagination
C240 - C250Publisher
American Physiological SocietyLocation
Bethesda, Md.Publisher DOI
ISSN
0363-6143eISSN
1522-1563Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2010, American Physiological SocietyUsage metrics
Keywords
AnimalsCell LineCells, CulturedCitric Acid CycleDown-RegulationElectron TransportMiceMuscle Fibers, SkeletalPeroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alphaPyruvic AcidSubstrate SpecificityTrans-ActivatorsTranscription FactorsUp-RegulationScience & TechnologyLife Sciences & BiomedicineCell BiologyPhysiologyglutamineglucose metabolismType 2 diabetesperoxisome proliferator-activated receptor-gamma coactivator-1 alphaACTIVATED PROTEIN-KINASESKELETAL-MUSCLE CELLSMITOCHONDRIAL BIOGENESISPGC-1-RELATED COACTIVATORINSULIN-RESISTANCEMAMMALIAN-CELLSGENE-EXPRESSIONEXERCISEPGC-1-ALPHAAMPKPhysiology
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