FFAR4 and diabetes mellitus: Based on the fact that free fatty acid receptor (FFAR)1 and 4 (also known as GPR40 and GPR120, respectively) not only possess glycemic control effects by promoting GLP-1 production and inducing insulin secretion and sensitivity, but also have anti-inflammatory effects through inhibition of TAK1 (transforming growth factor-β-activated kinase 1) and the NLRP3 (NLR family pyrin domain containing 3) inflammasome, FFAR1/FFAR4 have been recognized as promising targets for diabetes and NASH treatment.