JCAD Deficiency Attenuates Activation of Hepatic Stellate Cells and Cholestatic Fibrosis

Background: Cholestatic liver diseases including primary biliary cholangitis (PBC) are associated with active hepatic fibrogenesis, which ultimately progresses to cirrhosis. Activated hepatic stellate cells (HSCs) are the main fibrogenic effectors in response to cholangiocyte damage. JCAD regulates cell proliferation and malignant transformation in NASH-HCC by interacting with LATS2 in the Hippo signaling pathway. However, its participation in cholestatic fibrosis has not been explored yet.Methods: Serial sections of liver tissue of PBC patients were immunohistochemically stained. Hepatic fibrosis was induced by bile duct ligation (BDL) in wild-type (WT), global JCAD knockout mice (JCAD-KO), and hepatic stellate cell-specific JCAD knockout mice (HSC-JCAD-KO), and evaluated by histopathology and biochemical tests. In situ-activated HSCs isolated from BDL mice were used to determine effects of JCAD on HSC activation.Findings: In consistence with staining of liver sections from PBC patients, immunofluorescent staining revealed that JCAD expression was in accordance with smooth muscle α-actin (α-SMA) and was significantly up-regulated in activated HSCs in WT mice with BDL. JCAD deficiency remarkably ameliorated BDL-induced hepatic injury and fibrosis, as documented by liver hydroxyproline content, when compared to WT mice with BDL. Histopathologically, collagen deposition was dramatically reduced in both JCAD-KO and HSC-JCAD-KO mice compared to WT mice, as visualized by Trichrome staining and semi-quantitative scores. Moreover, JCAD deprivation significantly attenuated in situ HSC activation and decreased expression of fibrotic genes after BDL.Interpretation: JCAD deficiency effectively suppressed hepatic fibrosis induced by BDL in mice, and the underlying mechanisms are largely through suppressed Hippo-YAP signaling activity in HSCs.Funding: This work is supported by the National Natural Science Foundation of China (NSFC #82370625, 82170624, 81871997, 81572356), Shanghai Commission of Sciences and Technologies (#16140903700), and the National Key R&D Program of China (#2016YFE0107400.) to J.W; Natural Science Foundation of Shanghai (#21ZR1450300) to X-P. L. Declaration of Interest: All authors declare that no conflict of interest is involved in participation or contribution to the present work.Ethical Approval: The procedures regarding human subjects were approved by the Ethic Committee of Fudan University School of Basic Medical Sciences (2022-C008). All animal experimental protocols (2021-0302-051, 2023-0301-088) were approved by the Ethic Committee for Experimental Animal Use and Care, Fudan University School of Basic Medical Sciences, and performed in line with the NIH Guidelines for Experimental Animal Handling and Use, as well as the national, municipal, and university regulations.