LAUSR

Background Dipeptidyl peptidase-4 inhibitors (DPP-4Is) are used clinically as oral antidiabetic agents. Although DPP-4Is are known to ameliorate liver fibrosis, the protective mechanism of DPP-4Is in liver fibrosis remains obscure. In this study, gemigliptin was used to investigate the potential of DPP-4Is to alleviate the progression of liver fibrosis. Methods To clarify the effects and mechanisms of gemigliptin, we conducted various experiments in LX-2 cells (immortalized human hepatic stellate cells [HSCs], the principal effectors of hepatic fibrogenesis), which were activated by succinate and exhibited elevated expression of α-smooth muscle actin, collagen type 1, and pro-inflammatory cytokines and increased cell proliferation. In vivo, we examined the effects and mechanisms of gemigliptin on a high-fat, high-cholesterol–induced mouse model of nonalcoholic steatohepatitis (NASH). Results Gemigliptin decreased the expression of fibrogenesis markers and reduced the abnormal proliferation of HSCs. In addition, gemigliptin reduced the succinate-induced production of mitochondrial reactive oxygen species (ROS), intracellular ROS, and mitochondrial fission in HSCs. Furthermore, in the mouse model of NASH-induced liver fibrosis, gemigliptin alleviated both liver fibrosis and mitochondrial dysfunction. Conclusion Gemigliptin protected against HSC activation and liver fibrosis by alleviating mitochondrial dysfunction and ROS production, indicating its potential as a strategy for preventing the development of liver disease.