UC Irvine

MicroRNAs are increasingly seen as targets of drug discovery because they influence gene function acting both to silence and subtly modulate protein translation. Little is known about effects of dynamic physiological states on microRNA regulation in humans. We hypothesized that microRNA expression in peripheral blood mononuclear cells (PBMCs) would be affected by brief exercise. Twelve young men performed brief bouts of heavy exercise. PBMC microRNA was analyzed before and immediately after exercise using the Agilent Human microRNA V2 Microarray. Exercise altered expression level of 34 microRNAs (FDR < 0.05). Many of them play roles in inflammatory processes (e.g., miR-125b[↓], down-regulated by proinflammatory factor LPS; and miR-132[↑], 125b[↓] and let-7e[↓] involved inTLR4 signaling). Using previous exercise data in PBMCs, we linked the microRNA changes to specific gene pathways. This analysis identified 12 pathways including the TGF-β and MAPK signaling. We also compared exercise-associated microRNA changes in PBMCs with the exercise-associated microRNAs previously identified in neutrophils. Nine microRNAs were affected in both PBMCs and neutrophils, but only six changed in the same direction. A commonly occurring physiologic perturbation, brief heavy exercise, changes microRNA profiles in PBMCs, many of which are related to inflammatory processes. The pattern of change suggests that exercise differentially influences microRNAs in leukocyte subtypes.