About this Research Topic
MicroRNAs (miRNAs) are small non-coding RNAs of approximately 19–22 nucleotides in length. A single miRNA can regulate the expression of hundreds of mRNAs and proteins by degrading mRNA molecules or, more frequently in mammalian cells, by inhibiting their translation. It has been suggested that miRNA-mediated gene regulation is a fundamental mechanism of post-transcriptional regulation and may have diverse functional effects. In fact, 30% of protein-coding genes may be regulated by miRNAs and several of these miRNAs are suggested to have a role in a wide range of biological processes, including development, cell death, carcinogenesis, and the response to stress. In the past 5 years, it has been shown that miRNAs play important roles in skeletal muscle function and several miRNAs are suggested to act as modulators of myogenesis, hypertrophy, and nutrient metabolism. Some of them also mediate muscle adaptations such as metabolic improvement and building muscle mass, in response to exercise and diet. In addition, miRNAs are associated with muscular pathogenesis such as dystrophy, insulin resistance, and disuse atrophy.
Growing evidences also showed that miRNAs are secreted from organ into circulation and function in an endocrine manner. Indeed, some miRNAs are taken into intracellular vesicles (e.g. exosomes) and released into circulation without being degraded by RNase. In addition, the circulating miRNAs (c-miRNAs) can move from circulation into other cells and regulate their functions via regulation of gene expression at the post-transcriptional level through translational inhibition or mRNA degradation. It has been shown that exercise or muscle disorders change the level of c-miRNAs, which suggests that skeletal muscle can regulate physiological functions in whole body depending on physical activity level. Several miRNAs are highly enriched in skeletal muscle and may be secreted from muscle into circulation. In the future, many other muscle-secreted miRNA could be identified, which may accelerate the understanding of the effect of exercise on improvement of physical performance and prevention of diseases, and also estimates adequate condition of exercise to obtain its beneficial effects.
This Research Topic aims to highlight and cover recent understanding regarding the role of miRNA in skeletal muscle function associated with exercise, diseases, and aging, which would be a unique opportunity to bring together leading experts in the field to provide a deep overview of current knowledge. Contributors are encouraged to submit reviews, mini-reviews, commentaries, perspectives, research articles and theoretical papers.
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