Acute Resistance Exercise Modifies Extracellular Vesicle miRNAs Targeting Anabolic Gene Pathways: A Prospective Cohort Study
BACKGROUND:  Resistance training confers numerous health benefits that are mediated in part by circulating factors. Towards an enhanced molecular understanding, there is growing interest in a class of signaling biomarkers called extracellular vesicles (EVs). Extracellular vesicles support physiological adaptations to exercise by transporting their cargo (e.g., microRNA [miRNA]) to target cells. Previous studies of changes in EV cargo have focused on aerobic exercise, with limited data examining the effects of resistance exercise. We examined the effect of acute resistance exercise on circulating EV miRNAs and their predicted target pathways. METHODS:  Ten participants (5 men; age: 26.9±5.5 y, height: 1.7±0.1 m, body mass: 74.0±11.1 kg, body fat: 25.7±11.6 %) completed an acute heavy resistance exercise test (AHRET) consisting of six sets of 10 repetitions of back squats using 75% one-repetition maximum. Pre-/post-AHRET, EVs were isolated from plasma using size exclusion chromatography, and RNA sequencing was performed. Differentially expressed (DE) miRNAs between pre- and post-AHRET EVs were analyzed using Ingenuity Pathway Analysis to predict target messenger RNAs and their target biological pathways. RESULTS:  Overall, 34 miRNAs were altered by AHRET (p<0.05), targeting 4,895 mRNAs, with enrichment of 175 canonical pathways (p<0.01), including 12 related to growth/metabolism (p53, IGF-I, STAT3, PPAR, JAK/STAT, growth hormone, WNT/ß-catenin, ERK/MAPK, AMPK, mTOR, and PI3K/AKT) and eight to inflammation signaling (TGF-ß, IL-8, IL-7, IL-3, IL-6, IL-2, IL-17, IL-10). CONCLUSION:  Acute resistance exercise alters EV miRNAs targeting pathways involved in growth, metabolism, and immune function. Circulating EVs may serve as significant adaptive signaling molecules influenced by exercise training. Overall design: Repeated measures study, pre- and immediate-post acute resistance exercise