Expression Profiling of Horse Circulating miRNAs after Endurance Competition

Advances in molecular biology and bioinformatics combined with exercise physiology, have identified many key signaling pathways responsible for exercise-induced adaptations. Noncoding RNAs, and specifically micro RNAs (miRNAs), constitute a new regulatory component that may play a role in these adaptations. Research efforts on miRNA role in exercise in human sport medicine has predominantly focused on plasma where miRNAs are carried by extra cellular vesicles (exosomes) or high-density lipoprotein delivering messages to cells facilitating tissues crosstalk. This messenger role together with other key features such as body fluid stability and specific expression profile make miRNAs optimal biomarkers in physiological and pathological scenarios.

We applied NGS technology to obtain a landscape of the small RNA content of these important cargos in a time course experimental design: serum from 4 horses that participated to international endurance races was collected before and after the effort. 101 small RNAs (including miRNA and ncRNAs) resulted differentially expressed in plasma after the competition and the most up-regulated circulating miRNAs appeared to be: mir-1, mir-206 and mir-133a (also known as myomiRs), mir-146, mir-149, mir-208 and mir-214 as also results from recent literature evidences in human marathoner. Full results of differentially expressed small RNAs due to the competition are presented and discussed.