Irisin, a fascinating field in our times. (September 2022) - Bao, Jing-Fu
Abstract : Irisin is a muscle-secreted hormone that is generated by cleavage of membrane protein FNDC-5 (fibronectin type III domain-containing protein 5). Irisin is considered to be a mediator of exercise-induced metabolic improvements, such as browning of white adipose tissue, and is known to alleviate several chronic non-metabolic diseases. Thus, irisin may be an ideal therapeutic target for metabolic and non-metabolic diseases. However, several controversies regarding irisin have hindered its clinical translation. We review the generation, regulation (especially in exercise), and metabolic as well as therapeutic effects of irisin on metabolic and non-metabolic diseases. Furthermore, we discuss controversies regarding irisin and highlight potential future research directions. Highlights: Irisin is an exercise-induced hormone that is involved in systemic metabolic regulation and metabolic diseases. Irisin is highly expressed in myocytes and is generated by cleavage of a membrane protein or is even directly released by myocytes. Acute exercise can promote irisin secretion, but the effects of chronic exercise on irisin secretion remain under debate. Irisin demonstrates significant protective effects on multiple non-metabolic diseases. Exogenous irisin administration could be an ideal therapeutic strategy for metabolic and non-metabolic diseases.