Endurance Training‐mediated Differential Regulation of miRNAs in Skeletal Muscle of Lean and Obese Men

MicroRNAs (miRNAs) are evolutionarily conserved small non‐coding RNA species involved in post‐transcriptional gene regulation. In skeletal muscle, an acute bout of endurance exercise differentially alters miRNA species that regulate transcriptional networks involved in mitochondrial biogenesis, glucose and fatty acid metabolism, and muscle remodeling. The purpose of this study was to assess the expressional profile of targeted miRNAs following 3‐mo of endurance training in sedentary lean and obese men (N=5/group). The expression of miR‐ 100, 144, 190, 424, 668, and 923 was measured in the vastus lateralis before and after the program. Basal expression of miR‐424 was 160% greater (P<0.02), whereas miR‐144 was reduced by 77% (P=0.06) in the obese compared to the lean group. Endurance training significantly increased the expression of miR‐424 in both groups (P<0.01). Interestingly, the expression of miR‐144 in the obese was normalized to lean controls post endurance training (P=0.06). No changes were observed in miR‐100, 190, 668, and 923. We conclude that investigation of these molecules and their genetic targets may potentially identify new pathways involved in the pathology of complex metabolic diseases, improving our understanding of metabolic disorders and influence future approaches to the treatment of obesity. Research supported by CIHR.