CircularRNA and Musculoskeletal Diseases.

The skeletal muscle is the largest organ in the human body and plays a crucial role in the locomotion, metabolism, and homeostasis. Myogenesis is regulated by a complex molecular network and is kept finely balanced under physiological conditions. The disorder of muscular homeostasis results in musculoskeletal diseases, including myositis, dystrophy, sarcopenia, atrophy, and cachexia. These diseases severely affect the life quality of humans. In recent years, with the progress of high-throughput sequencing technology and the development of bioinformatics, a large number of noncoding RNAs (ncRNAs) have been identified in the skeletal muscle, and numerous experiments to date have shown that those ncRNAs are widely involved in multiple pathophysiological process of skeletal muscle. Circular RNAs (circRNA) are a class of noncoding RNAs formed by covalently closed loops through back-splicing and exon skipping. circRNAs have been confirmed to play a vital role in various biological functions, acting as microRNA sponges and reservoirs, as well as combining with RNA-binding proteins during the progression of myogenesis. In this chapter, we will summarize the progress of circRNA in regulating skeletal muscle and provide new information to better understand muscle diseases development and therapeutic strategy.