Muscle-derived Extracellular Vesicles and Their Interactions With Adipocytes in Human Metabolic Dysfunction

Numerous studies in humans and animals have shown that aerobic exercise is beneficial to adipose tissue function and whole-body metabolism. Both acute and chronic aerobic exercise enhance adipocyte catecholamine sensitivity in humans and animals. Although relatively few studies have investigated whether adipose adrenergic signaling is affected by resistance exercise (RE), it is known that a single bout of RE can increase circulating NEFA and resting energy expenditure and decrease respiratory quotient for up to 24 hours, indicative of increased adipocyte lipolysis and muscle fatty acid oxidation. Furthermore, the lipolytic response to RE is impaired in obese men. Using synergist ablation, a model of RE in mice, the investigators show that adipose transcriptional responses are exosome-dependent, and that serum exosomes enhance adipocyte catecholamine sensitivity and lipolysis for at least 24 hours. To the investigator's knowledge, this is the first demonstration of a potential mechanism whereby RE imparts metabolic adaptations in adipose. Since adipose metabolic function is crucial for determining whole-body metabolic outcomes, the ability of RE-induced exosomes to improve adipose metabolism has significant clinical implications.