title: Time course of proteolytic, cytokine, and myostatin gene expression after acute exercise in human skeletal muscle.
abstract: The aim of this study was to examine the time course induction of select proteolytic [muscle ring finger-1 (MuRF-1), atrogin-1, forkhead box 3A (FOXO3A), calpain-1, calpain-2], myostatin, and cytokine (IL -6, -8, -15, and TNF-alpha) mRNA after an acute bout of resistance (RE) or run (RUN) exercise. Six experienced RE (25 +/- 4 yr, 74 +/- 14 kg, 1.71 +/- 0.11 m) and RUN (25 +/- 4 yr, 72 +/- 5 kg, 1.81 +/- 0.07 m) subjects had muscle biopsies from the vastus lateralis (RE) or gastrocnemius (RUN) before, immediately after, and 1, 2, 4, 8, 12, and 24 h postexercise. RE increased (P < 0.05) mRNA expression of MuRF-1 early (3.5-fold, 1-4 h), followed by a decrease in atrogin-1 (3.3-fold) and FOXO3A (1.7-fold) 8-12 h postexercise. Myostatin mRNA decreased (6.3-fold; P < 0.05) from 1 to 24 h postexercise, whereas IL-6, IL-8, and TNF-alpha mRNA were elevated 2-12 h. RUN increased (P < 0.05) MuRF-1 (3.6-fold), atrogin-1 (1.6-fold), and FOXO3A (1.9-fold) 1-4 h postexercise. Myostatin was suppressed (3.6-fold; P < 0.05) 8-12 h post-RUN. The cytokines exhibited a biphasic response, with immediate elevation (P < 0.05) of IL-6, IL-8, and TNF-alpha, followed by a second elevation (P < 0.05) 2-24 h postexercise. In general, the timing of the gene induction indicated early elevation of proteolytic genes, followed by prolonged elevation of cytokines and suppression of myostatin. These data provide basic information for the timing of human muscle biopsy samples for gene expression studies involving exercise. Furthermore, this information suggests a greater induction of proteolytic genes following RUN compared with RE.
authors.affiliation: Human Performance Laboratory, Ball State Univ., Muncie, IN 47306, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Louis
authors.forename: Ulrika
authors.initials: U
authors.lastname: Raue
authors.forename: Yifan
authors.initials: Y
authors.lastname: Yang
authors.forename: Bozena
authors.initials: B
authors.lastname: Jemiolo
authors.forename: Scott
authors.initials: S
authors.lastname: Trappe
mesh_terms: D000328:Adult; D002154:Calpain / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D005260:Female; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007378:Interleukins / Q000378:metabolism; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D055435:Myostatin; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012420:Running; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism; D013997:Time Factors; D015533:Transcriptional Activation; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D000070584:Tripartite Motif Proteins; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism