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Aging is associated with a dysregulated human skeletal muscle microRNA‐499 and ‐208b expression following resistance exercise
Author(s) -
Drummond Micah J,
Fry Christopher S,
Glynn Erin L,
Timmerman Kyle L,
Volpi Elena,
Rasmussen Blake B
Publication year - 2010
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.24.1_supplement.997.11
Subject(s) - sarcopenia , myogenesis , skeletal muscle , microrna , medicine , anabolism , endocrinology , myostatin , downregulation and upregulation , gene expression , resistance training , biology , gene , genetics
MicroRNAs (miRNA) are novel post‐transcriptional gene regulators associated with skeletal muscle myogenesis and tissue regeneration. Sarcopenia is associated with resistance to anabolic stimuli such as exercise and nutrition. Therefore, we hypothesized that skeletal muscle miRNA expression after exercise would be dysregulated in older humans and may play a role in the etiology of this anabolic resistance. To address our hypothesis, young (n=5) and older (n=5) male subjects participated in a single bout of leg resistance exercise and vastus lateralis muscle biopsies were sampled at Basal, 6 and 24h postexercise. Samples were analyzed utilizing real‐time PCR for gene expression levels of miR‐1, ‐206, ‐499, and ‐208b. We found that miR‐499 and ‐208b expression were upregulated at 6h postexercise in young (P<0.05) but unchanged in older subjects. MiRNA‐1 and ‐206 were downregulated at 6 and 24h postexercise in both groups (P<0.05). Myostatin (predicted target of miR‐499 and ‐208b) expression was decreased at 6 and 24h postexercise in both groups. IGF‐1 (predicted target of miR‐1 and ‐206) expression was elevated at 6 and 24h postexercise only in the young. We conclude that a bout of heavy resistance exercise alters the expression of human skeletal muscle miRNAs, however, aging is associated with an inability of exercise to alter miR‐499 or ‐208b. Identifying gene targets of these miRNAs will be the focus of future work. Supported by NIA P30 AG‐024832 (MJD) & NIAMS grant R01 AR049877 (BBR)