Exercise, Gut Microbial Metabolite: Short Chain Fatty Acid andRegulation of Skeletal Muscle Metabolism / 中国生物化学与分子生物学报

ABSTRACT

Gut microbiota, which is influenced by genetics, environment, diet, age and exercise, is a highly dynamic and individualized complex ecosystem and has a wide range of response effects with many tissues and organs through its metabolites. Short chain fatty acids (SCFA) are mainly produced by bacteria in cecum and colon by fermentation with dietary fiber as substrate, which is absorbed into the superior and inferior mesenteric vein, and then converges into the portal vein to the liver. Part of SCFA is used as the substrate of gluconeogenesis and lipid biosynthesis by liver, and the remaining SCFA enters the peripheral circulation through hepatic vein in the form of free fatty acids. It is found that exercise can improve the abundance of gut microbiota producing SCFA and the expression of genes involved in the regulation of SCFA production, and then increase the content of SCFA in the lumen. Glucagon likepeptide-1 (GLP-1) is synthesized and secreted by colon endocrine cells stimulated by SCFA. GLP-1 can promote islet B cells to synthesize and secrete insulin, which regulates skeletal muscle glucose uptake and glycogen synthesis. In addition, SCFA enhances the insulin sensitivity of skeletal muscle by increasing histone acetylation level on chromatin in proximity of the insulin receptor substrate 1 (Irs1) transcriptional start site. At the same time, SCFA can promote fatty acid uptake, lipid catabolism andmitochondrial biogenesis of skeletal muscle by activating AMP-activated protein kinase (AMPK), and then inhibit lipid anabolism. This paper reviewed the latest research progress in three aspects summary of the gut microbial metabolites (SCFA), the effect of exercise on the gut microbiota producing SCFA, and the possible mechanism of exercise mediated SCFA on skeletal muscle metabolism. It may provide theoretical basis for the research on the new mechanism in the exercise adaptation of skeletal muscle.