Effects of endurance racing on horse plasma extracellular particle miRNA.

BACKGROUND: Physical exercise is an essential factor in preventing and treating metabolic diseases by promoting systemic benefits throughout the body. The molecular factors involved in this process are poorly understood. Micro RNAs (miRNAs) are small non-coding RNAs that inhibit mRNA transcription. MiRNAs, which can participate in the benefits of exercise to health, circulate in plasma in extracellular particles (EP). Horses that undergo endurance racing are an excellent model to study the impact of long-duration/low intensity exercise in plasma EP miRNAs. OBJECTIVES: To evaluate the effects of 160 km endurance racing on horse plasma extracellular particles and their miRNA population. STUDY DESIGN: Cohort study. METHODS: We collected plasma from five Arabian horses during five time-points of an endurance ride. Extracellular particles were purified from plasma and characterised by electron microscopy, resistive pulse sensing (qNano) and western blotting. Small RNAs were purified from horse plasma EP, and sequencing was performed. RESULTS: Endurance racing increased EP concentration and average diameter compared to before the race. Western blotting showed a high concentration of extracellular vesicles proteins 2 hours after the race, which returned to baseline 15 hours after the race. MicroRNA differential expression analysis revealed increasing levels of eca-miR-486-5p during and after the race, and decreasing levels of eca-miR-9083 after the end. CONCLUSIONS: This study adds new data about the variation in plasma EP concentrations after long-distance exercise and brings new insights about the roles of exercise-derived EP miRNAs during low-intensity endurance exercise.

Effects of Acute Aerobic Exercise on Rats Serum Extracellular Vesicles Diameter, Concentration and Small RNAs Content.

Physical exercise stimulates organs, mainly the skeletal muscle, to release a broad range of molecules, recently dubbed exerkines. Among them, RNAs, such as miRNAs, piRNAs, and tRNAs loaded in extracellular vesicles (EVs) have the potential to play a significant role in the way muscle and other organs communicate to translate exercise into health. Low, moderate and high intensity treadmill protocols were applied to rat groups, aiming to investigate the impact of exercise on serum EVs and their associated small RNA molecules. Transmission electron microscopy, resistive pulse sensing, and western blotting were used to investigate EVs morphology, size distribution, concentration and EVs marker proteins. Small RNA libraries from EVs RNA were sequenced. Exercise did not change EVs size, while increased EVs concentration. Twelve miRNAs were found differentially expressed after exercise: rno-miR-128-3p, 103-3p, 330-5p, 148a-3p, 191a-5p, 10b-5p, 93-5p, 25-3p, 142-5p, 3068-3p, 142-3p, and 410-3p. No piRNA was found differentially expressed, and one tRNA, trna8336, was found down-regulated after exercise. The differentially expressed miRNAs were predicted to target genes involved in the MAPK pathway. A single bout of exercise impacts EVs and their small RNA load, reinforcing the need for a more detailed investigation into EVs and their load as mediators of health-promoting exercise.