Rapid exercise-induced changes in PGC-1alpha mRNA and protein in human skeletal muscle.
The mRNA of the nuclear coactivator peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) increases during prolonged exercise and is influenced by carbohydrate availability. It is unknown if the increases in mRNA reflect the PGC-1alpha protein or if glycogen stores are an important regulator. Seven male subjects [23 +/- 1.3 yr old, maximum oxygen uptake (Vo(2 max)) 48.4 +/- 0.8 ml.kg(-1).min(-1)] exercised to exhaustion ( approximately 2 h) at 65% Vo(2 max) followed by ingestion of either a high-carbohydrate (HC) or low-carbohydrate (LC) diet (7 or 2.9 g.kg(-1).day(-1), respectively) for 52 h of recovery. Glycogen remained depressed in LC (P < 0.05) while returning to resting levels by 24 h in HC. PGC-1alpha mRNA increased both at exhaustion (3-fold) and 2 h later (6.2-fold) (P < 0.05) but returned to rest levels by 24 h. PGC-1alpha protein increased (P < 0.05) 23% at exhaustion and remained elevated for at least 24 h (P < 0.05). While there was no direct treatment effect (HC vs. LC) for PGC-1alpha mRNA or protein, there was a linear relationship between the changes in glycogen and those in PGC-1alpha protein during exercise and recovery (r = -0.68, P < 0.05). In contrast, PGC-1beta did not increase with exercise but rather decreased (P < 0.05) below rest level at 24 and 52 h, and the decrease was greater (P < 0.05) in LC. PGC-1alpha protein content increased in prolonged exercise and remained upregulated for 24 h, but this could not have been predicted by the changes in mRNA. The beta-isoform declined rather than increasing, and this was greater when glycogen was not resynthesized to rest levels.
Mathai
Anila S
AS
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
Bonen
Arend
A
Benton
Carley R
CR
Robinson
D L
DL
Graham
Terry E
TE
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D018592:Cross-Over Studies; D050528:Diet, Carbohydrate-Restricted; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006003:Glycogen / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism*; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins; D020127:Recovery of Function; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D001786:Blood Glucose; D002352:Carrier Proteins; D004040:Dietary Carbohydrates; D005230:Fatty Acids, Nonesterified; D006360:Heat-Shock Proteins; D007328:Insulin; C486497:PPARGC1A protein, human; C455622:PPARGC1B protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D006003:Glycogen