title: Short-term intensified cycle training alters acute and chronic responses of PGC1α and Cytochrome C oxidase IV to exercise in human skeletal muscle.
abstract: Reduced activation of exercise responsive signalling pathways have been reported in response to acute exercise after training; however little is known about the adaptive responses of the mitochondria. Accordingly, we investigated changes in mitochondrial gene expression and protein abundance in response to the same acute exercise before and after 10-d of intensive cycle training. Nine untrained, healthy participants (mean±SD; VO(2peak) 44.1±17.6 ml/kg/min) performed a 60 min bout of cycling exercise at 164±18 W (72% of pre-training VO(2peak)). Muscle biopsies were obtained from the vastus lateralis muscle at rest, immediately and 3 h after exercise. The participants then underwent 10-d of cycle training which included four high-intensity interval training sessions (6×5 min; 90-100% VO(2peak)) and six prolonged moderate-intensity sessions (45-90 min; 75% VO(2peak)). Participants repeated the pre-training exercise trial at the same absolute work load (64% of pre-training VO(2peak)). Muscle PGC1-α mRNA expression was attenuated as it increased by 11- and 4- fold (P<0.001) after exercise pre- and post-training, respectively. PGC1-α protein expression increased 1.5 fold (P<0.05) in response to exercise pre-training with no further increases after the post-training exercise bout. RIP140 protein abundance was responsive to acute exercise only (P<0.01). COXIV mRNA (1.6 fold; P<0.01) and COXIV protein expression (1.5 fold; P<0.05) were increased by training but COXIV protein expression was decreased (20%; P<0.01) by acute exercise pre- and post-training. These findings demonstrate that short-term intensified training promotes increased mitochondrial gene expression and protein abundance. Furthermore, acute indicators of exercise-induced mitochondrial adaptation appear to be blunted in response to exercise at the same absolute intensity following short-term training.
authors.affiliation: Institute of Sport Exercise and Active Living, Victoria University, Footscray, Victoria, Australia. Nigel.Stepto@vu.edu.au
authors.forename: Nigel K
authors.initials: NK
authors.lastname: Stepto
authors.forename: Boubacar
authors.initials: B
authors.lastname: Benziane
authors.forename: Glenn D
authors.initials: GD
authors.lastname: Wadley
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Chibalin
authors.forename: Benedict J
authors.initials: BJ
authors.lastname: Canny
authors.forename: Nir
authors.initials: N
authors.lastname: Eynon
authors.forename: Glenn K
authors.initials: GK
authors.lastname: McConell
mesh_terms: D000293:Adolescent; D000328:Adult; D001642:Bicycling / Q000502:physiology*; D003576:Electron Transport Complex IV / Q000235:genetics* / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010806:Physical Education and Training / Q000379:methods*; D005082:Physical Exertion / Q000502:physiology; D020127:Recovery of Function / Q000235:genetics / Q000502:physiology; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D055815:Young Adult
chemical_list: D006360:Heat-Shock Proteins; C486497:PPARGC1A protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D014157:Transcription Factors; D003576:Electron Transport Complex IV