Irisin, an exercise-induced bioactive peptide beneficial for health promotion during aging process.

Irisin is an exercise-induced myokine expressed as a bioactive peptide in multiple tissues and organs, and exercise and cold exposure are the major inducers for its secretion. Irisin presents a decreasing trend with the extension of age and is also closely associated with a wide range of aging-related diseases. Currently, many studies on irisin are being conducted with respect to physiological functions for health promotion, and the prevention, treatment and rehabilitation of chronic diseases, as well as mechanisms associated with improving energy metabolic balance, enhancing cellular homeostasis by optimizing autophagy, promoting mitochondrial quality control, reducing reactive oxygen species (ROS) production, and mitigating inflammatory responses. These diseases include: metabolic diseases (obesity, type 2 diabetes, and bone metabolism); cardiovascular diseases (hypertension, coronary heart disease, cardiomyopathy and stroke); nervous system diseases (Alzheimer's disease, Parkinson's disease, and stroke); and others (cancer and sarcopenia). Although the current studies on irisin are relatively extensive, some studies have produced unexplained experimental results. This article introduces an overview of the generation, secretion, and tissue distribution, of irisin, and its targeting of tissues or organs for the prevention and treatment of above-mentioned chronic diseases is systematically summarized, with discussion of the underlying molecular mechanisms. This study is expected to improve the understanding of irisin, which may be beneficial to identify novel and effective targets for the screening, diagnosis, or therapy of these chronic diseases, or develop promising interventional strategies, effective drug candidates, functional foods, or exercise mimetics.