Hyodeoxycholic acid ameliorates the senescence of cholangiocyte and inflammasome activation in cholestatic liver diseases by activating mitophagy

Cholangiocytes function as a signaling hub in cholestatic liver disease (CLD), which prone to acquiring a proinflammatory, profibrogenic senescence-associated secretory phenotype (SASP), resulting in macrophages inflammasome activation. Hyodeoxycholic acid (HDCA), a major component of porcine bile powder, is emerging as a potential therapeutic agent for CLD, warranting further investigation. To investigate whether HDCA protects against CLD by regulating cholangiocytes senescence and macrophages inflammation. Bile duct ligation (BDL)-induced cholestatic murine model was established, Bulk RNA sequencing (RNA-seq) of livers, together with pharmacological studies in cholangiocytes and macrophages, were conducted. We found that HDCA administration effectively alleviated BDL-induced ductular reaction, inflammation, and fibrosis. Mechanistically, excessive accumulation of taurochenodeoxycholic acid (TCDCA) during cholestasis triggered mitochondrial damage and mitochondrial oxidative-DNA release in cholangiocytes. The leaked mitochondrial DNA activated STING, thereby promoting cholangiocytes senescence and upregulating proinflammatory SASP components, which subsequently contributed to AIM2/NLRP3 inflammasomes activation in macrophages. These detrimental effects were markedly attenuated by HDCA through induction of Takeda G protein-coupled receptor 5 (TGR5)-dependent protective mitophagy in cholangiocytes. Moreover, the inhibitory effect of HDCA on macrophages inflammasome activation was also dependent on TGR5 stimulation in macrophages. Conversely, pharmacological TGR5 inhibition with SBI115 markedly exacerbated cholangiocytes injury, inflammasome activation of macrophages, and their crosstalk. Taken together, HDCA protects against CLD through a dual TGR5-dependent mechanism: promoting protective autophagy in cholangiocytes and suppressing inflammasome activation in macrophages. These findings demonstrated that, through modulating TGR5-autophagy/inflammation axis, HDCA is a promising therapeutic agent for CLD.