Impact of endurance exercise training on adipocyte microRNA expression in overweight men

Adipocytes are major regulators of metabolism, and endurance exercise training improves adipocyte function; however, the molecular mechanisms that regulate chronic adaptive responses remain unresolved. microRNAs (miRNAs) influence adipocyte differentiation and metabolism. Accordingly, we aimed to determine whether adipocyte miRNA expression is responsive to exercise training and to identify exercise-responsive miRNAs that influence adipocyte metabolism. Next-generation sequencing was used to profile miRNA expression of adipocytes that were isolated from abdominal subcutaneous (ABD) and gluteofemoral (GF) adipose tissue of overweight men before and after 6 wk of endurance exercise training. Differentially expressed miRNAs were overexpressed or silenced in 3T3-L1 adipocytes, and lipid metabolism was examined. Next-generation sequencing identified 526 miRNAs in adipocytes, and there were no statistical differences in miRNA expression when comparing pre- and post-training samples for ABD and GF adipocytes. miR-10b expression was increased in ABD compared with GF adipocytes, whereas miR-204, miR-3613, and miR-4532 were more highly expressed in GF compared with ABD adipocytes. Blocking miR-10b in adipocytes suppressed β-adrenergic lipolysis but generally had a minor effect on lipid metabolism. Thus, unlike their critical role in adipogenesis, stable changes in miRNA expression do not play a prominent role in the regulation of adipocyte function in response to endurance exercise training.-Tsiloulis, T., Pike, J., Powell, D., Rossello, F. J., Canny, B. J., Meex, R. C. R., Watt, M. J. Impact of endurance exercise training on adipocyte microRNA expression in overweight men.