About this Research Topic
Regular physical activity results in metabolic and physiological adaptations, not only at the level of skeletal muscle itself, but also in distant organs. Furthermore, chronic physical activity is known to be one of the best non-pharmacological interventions for the prevention and treatment of many diseases, including chronic diseases such as type 2 diabetes, cancers, arthritis, and heart diseases, but also psychological disorders such as depression, anxiety, and post-traumatic stress disorders. How contracting muscle mediates the diverse metabolic and physiological adaptations that are beneficial for health is not well understood and remains elusive. In the last century, researchers have sought for targets that could be modulated to recapitulate the beneficial effects of exercise. It was only 15 years ago, that B.K. Pedersen and collaborators demonstrated that contracting skeletal muscles secrete small peptides that they named myokines. Myokines act as endocrine factors to improve the function of distant organs, but also locally on skeletal muscle in an autocrine/paracrine fashion. Secretion of myokines by contracting skeletal muscle may explain part of the beneficial effects of chronic exercise training on general health, as well as muscle metabolic adaptations to exercise training. However, myokines are not the only factors secreted by skeletal muscle during contraction. Since the years 2010, multiple evidence for exercise-induced skeletal muscle secretion of miRNA and more recently, mitochondrial DNA, are accumulating. A number of metabolites and enzymes are also secreted by contracting skeletal muscles. In the past five years, the role of exosomes in the transport of some of these factors has been highlighted.
Only a small number of muscle-derived secreted factors has been identified to date, and the role of each of them is far from being understood. Furthermore, the role of the entire muscle secretome in the metabolic and physiological adaptations to exercise has rarely been studied. In addition, which type of exercise (resistance vs aerobic vs high interval training, duration, frequency, etc.) favors the secretion of these factors is still under investigation.
The aim of this Research Topic is to provide a platform for original research and review articles that shed more light on the role of muscle-derived secreted factors in the adaptations to exercise training. We encourage interested scientists, clinicians, and exercise specialists to submit their contributions with a specific focus on:
• understanding the role of the whole muscle secretome (i.e. additive and synergistic role of different muscle-derived secreted factors) in the physiological and metabolic adaptations to exercise;
• optimizing exercise for the secretion of these factors by skeletal muscle.
Keywords: Myokines, circulating miRNA, circulating mitochondrial DNA, muscle-derived secreted factors, exercise
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.