Bidirectional regulation of free fatty acid receptors and non-alcoholic fatty liver disease.

Free fatty acid receptor action is primarily in the area of energy modulation and maintenance of normal metabolism in the body. They have been identified and attributed to specific G protein-coupled receptors (GPCRs). Currently, the main findings include four receptors: FFAR1 to FFAR4. Free fatty acids (FFAs) with different carbon chain lengths respond to different FFAR. Short-chain fatty acids (C2-C6) bind specifically to FFAR2 and FFAR3, whereas medium-chain fatty acids (C6-C12) and long-chain fatty acids (C13-C21) target both FFAR1 and FFAR4. FFARs have been considered as potential target for the treatment of common metabolic diseases such as T2M, cardiovascular diseases and inflammatory bowel diseases. Nonalcoholic fatty liver disease is a common metabolic disorder and is often accompanied by various metabolic and cardiovascular diseases. The expression and modulation of FFARs in the body may be related to the development of nonalcoholic fatty liver disease. This article introduces the source, synthesis and metabolic pathways of fatty acids, and comprehensively summarizes the research on FFARs signal transduction and its physiological functions, the regulation between FFARs and NAFLD, and the prospect of FFARs-based treatment of NAFLD.