title: Transcriptional control, but not subcellular location, of PGC-1α is altered following exercise in a hot environment.
abstract: The purpose of this study was to determine mitochondrial biogenesis-related mRNA expression, binding of transcription factors to the peroxisome proliferator-activated receptor-γ coactivator 1-α (PGC-1α) promoter, and subcellular location of PGC-1α protein in human skeletal muscle following exercise in a hot environment compared with a room temperature environment. Recreationally trained males (n = 11) completed two trials in a temperature- and humidity-controlled environmental chamber. Each trial consisted of cycling in either a hot (H) or room temperature (C) environment (33 and 20°C, respectively) for 1 h at 60% of maximum wattage (Wmax) followed by 3 h of supine recovery at room temperature. Muscle biopsies were taken from the vastus lateralis pre-, post-, and 3 h postexercise. PGC-1α mRNA increased post (P = 0.039)- and 3 h postexercise in C (P = 0.002). PGC-1α, estrogen-related receptor-α (ERRα), and nuclear respiratory factor 1 (NRF-1) mRNA was all lower in H than C post (P = 0.038, P < 0.001, and P = 0.030, respectively)- and 3 h postexercise (P = 0.035, P = 0.007, and P < 0.001, respectively). Binding of cAMP response element-binding protein (CREB) (P = 0.005), myocyte enhancer factor 2 (MEF2) (P = 0.047), and FoxO forkhead box class-O1 (FoxO1) (P = 0.010) to the promoter region of the PGC-1α gene was lower in H than C. Nuclear PGC-1α protein increased postexercise in both H and C (P = 0.029) but was not different between trials (P = 0.602). These data indicate that acute exercise in a hot environment blunts expression of mitochondrial biogenesis-related mRNA, due to decreased binding of CREB, MEF2, and FoxO1 to the PGC-1α promoter.
authors.affiliation: Department of Kinesiology, Washburn University, Topeka, Kansas;
authors.forename: Matthew W
authors.identifier: 0000-0002-9781-8110
authors.initials: MW
authors.lastname: Heesch
authors.affiliation: School of Health, Physical Education, and Recreation, University of Nebraska at Omaha, Omaha, Nebraska; and.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Shute
authors.affiliation: Department of Chemistry, University of Nebraska at Omaha, Omaha, Nebraska.
authors.forename: Jodi L
authors.initials: JL
authors.lastname: Kreiling
authors.affiliation: School of Health, Physical Education, and Recreation, University of Nebraska at Omaha, Omaha, Nebraska; and dslivka@unomaha.edu.
authors.forename: Dustin R
authors.initials: DR
authors.lastname: Slivka
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology; D000328:Adult; D017753:Ecosystem; D015444:Exercise / Q000502:physiology*; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D008931:Mitochondria, Muscle / Q000502:physiology*; D013347:Subcellular Fractions / Q000378:metabolism*; D000071436:Thermotolerance / Q000502:physiology*; D015533:Transcriptional Activation / Q000502:physiology*; D055815:Young Adult
keywords: heat stress; mitochondrial biogenesis; skeletal muscle