Conjugated bile acids facilitate cholangiocyte senescence to promote cholestatic liver diseases via STING signaling

Introduction Cholestatic liver disease can progress to advanced stages if left untreated and is lack of effective therapeutic options, highlighting the urgent need for new therapeutic targets. Objectives We aim to investigate the involvement of conjugated bile acids and STING signaling in the progression of cholestatic liver diseases. Methods We studied cholestatic liver injury in patients with primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), as well as in Abcb4 -/- mice and in mice subjected to bile duct ligation (BDL). Single-cell RNA sequencing (scRNA-seq) of clinical samples, bulk RNA sequencing (RNA-seq) of isolated primary hepatic cells, and abundant biochemical analysis were analyzed to reveal the damage-response pattern during cholestasis. Results We found that STING activation was correlated with the severity of liver injuries in patients with PBC and PSC, as well as in BDL and Abcb4 -/- mice. Tmem173 -/- mice exhibited significant protection against cholestasis-induced ductular reaction, inflammation, and fibrosis. Mechanistically, our results uncovered the cellular heterogeneity of the damage-response pattern during cholestasis. In cholangiocytes, substantial accumulation of conjugated primary bile acids significantly induced mitochondrial damage through the opening of the mitochondrial permeability transition pore, resulting in the production and leakage of oxidized DNA, which facilitates the establishment of senescence-associated secretory phenotype (SASP) by activating STING. The chemoattractive SASP of cholangiocytes then promoted the infiltration and activation of macrophages. Additionally, damage-associated molecular patterns derived from cholangiocytes further triggered the activation of inflammasome and non-lethal pyroptosis in macrophages, which were abrogated by pharmacological or genetic blockade of STING. Conclusion The present study delineates a novel intrahepatic damage-response map during cholestasis and underscores STING signaling as a promising therapeutic target for cholangiopathies.