18beta-glycyrrhetinic acid induces ROS-mediated apoptosis to ameliorate hepatic fibrosis by targeting PRDX1/2 in activated HSCs.

Hepatic stellate cells (HSCs) are essential drivers of fibrogenesis. Inducing activated-HSC apoptosis is a promising strategy for treating hepatic fibrosis. 18beta-glycyrrhetinic acid (18β-GA) is a natural compound that exists widely in herbal medicines, such as Fisch, which is used for treating multiple liver diseases, especially in Asia. In the present study, we demonstrated that 18β-GA decreased hepatic fibrosis by inducing the apoptosis in activated HSCs. 18β-GA inhibited the expression of α-smooth muscle actin and collagen type I alpha-1. Using a chemoproteomic approach derived from activity-based protein profiling, together with cellular thermal shift assay and surface plasmon resonance, we found that 18β-GA covalently targeted peroxiredoxin 1 (PRDX1) and peroxiredoxin 2 (PRDX2) proteins via binding to active cysteine residues and thereby inhibited their enzymatic activities. 18β-GA induced the elevation of reactive oxygen species (ROS), resulting in the apoptosis of activated HSCs. knockdown also led to ROS-mediated apoptosis in activated HSCs. Collectively, our findings revealed the target proteins and molecular mechanisms of 18β-GA in ameliorating hepatic fibrosis, highlighting the future development of 18β-GA as a novel therapeutic drug for hepatic fibrosis.