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Differential myogenic and cell cycle gene translation following unaccustomed resistance loading may contribute to disparate myofiber hypertrophy potential during resistance training
Author(s) -
Stec Michael John,
Thalacker-Mercer Anna,
Cui Xiangqin,
Merritt Ed,
Bamman Marcas
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1086.16
Subject(s) - myod , myogenin , muscle hypertrophy , cyclin d1 , myocyte , transcriptome , skeletal muscle , basal (medicine) , biology , cell cycle , microbiology and biotechnology , endocrinology , medicine , genetics , gene expression , gene , myogenesis , insulin
Mechanisms underlying disparate skeletal muscle hypertrophic responses to resistance training (RT) among individuals are largely unknown. 66 adults were clustered as non‐ (Non), modest (Mod), or extreme (Xtr) responders based on change in myofiber area after 16 wk RT. Via genomic microarray we identified large differences in the muscle transcriptome among response clusters prior to RT. We therefore analyzed muscle protein levels of select targets (HES6, annexin A2, ER‐alpha, myogenin, MyoD, cyclin D1, p21, p27, NFkB) before and 24 h after the first (unaccustomed) resistance exercise (RE) bout to determine if cluster differences in basal mRNA expression affected translational responses to RE. MyoD and p27 decreased in all clusters (P<0.05) while cluster x time intrxns (P<0.05) were found for HES6, myogenin, and cyclin D1. Compared to Mod and Xtr, basal HES6 and cyclin D1 tended to be lower in Non (P=0.10) and increased after RE only in Non (HES6 55%, cyclin D1 34%). These findings suggest the unique basal gene expression profile among Non may lead to differential translational responses to RE as compared to subjects who proficiently achieve RT‐induced myofiber hypertrophy (Mod and Xtr). Future research should determine whether unique translational patterns following unaccustomed RE play a role in the failed hypertrophy among Non. Support: 5R01AG017896, VA Merit, 5UL1 RR025777.