Cholestatic liver fibrosis is caused by obstruction of the biliary tract and is associated with early activation of portal fibroblasts (PFs) that express Thy-1, fibulin 2, and the recently identified marker mesothelin (MSLN). Here, we have demonstrated that activated PFs (aPFs) and myofibroblasts play a critical role in the pathogenesis of liver fibrosis induced by bile duct ligation (BDL). Conditional ablation of MSLN⁺ aPFs in BDL-injured mice attenuated liver fibrosis by approximately 50%. Similar results were observed in MSLN-deficient mice (Msln^–/– mice) or mice deficient in the MSLN ligand mucin 16 (Muc16^–/– mice). In vitro analysis revealed that MSLN regulates TGF-β1–inducible activation of WT PFs by disrupting the formation of an inhibitory Thy-1–TGFβRI complex. MSLN also facilitated the FGF-mediated proliferation of WT aPFs. Therapeutic administration of anti-MSLN–blocking Abs attenuated BDL-induced fibrosis in WT mice. Liver specimens from patients with cholestatic liver fibrosis had increased numbers of MSLN⁺ aPFs/myofibroblasts, suggesting that MSLN may be a potential target for antifibrotic therapy.

Double-negative (DN) T cells could delay the onset and the progression of autoimmune diabetes, yet they were less efficient on reversing autoimmune diabetes. The aim of this study was to investigate whether the combination of DN T cells and anti-thymocyte serum (ATS) could reverse new-onset diabetes in NOD mice. The regulation of different subsets of T cells in vitro and in vivo by ATS and DN T cells were examined using flow cytometry. At the day of diabetes onset, ATS was administered on the same day and 2 days later, and DN T cells were transferred at day 7. The reversion of diabetes was assessed by monitoring blood glucose levels. The efficacy of inhibition of DN T cells on CD8+ T cells was lower than that on CD4+ T cells both in vitro and in vivo. ATS resulted in a significant depletion of CD8+ T cells, while DN T cells were less sensitive to ATS depletion. 80 % diabetic NOD mice achieved long term (6 months) reversion of diabetes by combined ATS and DN T cells treatment, compared to 16 % in ATS single treatment and none in DN T cell single treatment. DN T cells preferentially resided in spleen and pancreatic draining lymph nodes in ATS plus DN T cells treated NOD mice. DN T cells plus ATS therapy show promising reversion effects on diabetic NOD mice due to a shift of balance from a destructive T cell response to one that favors DN T cell regulation.

Profibrogenesis cytokine, transforming growth factor‐ (TGF‐) β1, induces hepatic progenitors experiencing epithelial to mesenchymal transition (EMT) to matrix synthesis cells, even tumor initiating cells. Our previous data found that epidermal growth factor (EGF) blocks and reverses TGF‐β1‐induced transition. The aim of this study is to determine the characteristic changes of hepatic progenitors after TGF‐β1‐induced transition and EGF‐induced reversion. Hepatic oval cells, rat hepatic progenitors, were isolated from rats fed a choline‐deficient diet supplemented with ethionine. TGF‐β1‐containing medium was used for inducing EMT, while EGF‐containing medium was used for reversing EMT. During TGF‐β1‐induced transition and EGF‐induced reversion, hepatic oval cells sustained their progenitor cell marker expression, including α‐fetoprotein, albumin, and cytokeratin‐19. The proliferation ability and differentiation potential of these cells were suppressed by TGF‐β1, while EGF resumed these capacities to the level similar to the control cells. RNA microarray analysis showed that most of the genes with significant changes after TGF‐β1 incubation were recovered by EGF. Signal pathway analysis revealed that TGF‐β1 impaired the pathways of cell cycle and cytochrome P450 detoxification, and EGF reverted TGF‐β1 effects through activating MAPK and PI3K‐Akt pathway. EGF reverses the characteristics impaired by TGF‐β1 in hepatic oval cells, serving as a protective cytokine to hepatic progenitors.

Background: Hepcidin, a peptide hormone primarily produced by the liver, regulates iron metabolism by interacting with its receptor, ferroportin. Studies have demonstrated that hepcidin participates in the progression of liver fibrosis by regulating HSC activation, but its regulatory effect on hepatocytes remains largely unknown. Methods: A carbon tetrachloride (CCl₄)-induced liver fibrosis model was established in C57BL/6 wild-type (WT) and hepcidin knockout (Hamp ^−/−) mice. Liver injury and inflammation were assessed in WT and Hamp ^−/− mice at 24 and 48 hours following acute CCl₄ exposure. In addition, transcriptomic sequencing of primary hepatocytes was performed to compare gene expression profiles between WT and Hamp ^−/− mice 24 hours after liver injury. The function of the identified molecule Eif2ak3/PERK (protein kinase R(PKR)-like endoplasmic reticulum kinase), was evaluated both in vitro and in vivo. Results: We found that serum hepcidin significantly increased during the progression of liver fibrosis induced by CCl₄ and bile duct ligation. In addition, CCl₄-treated Hamp ^−/− mice developed more severe liver injury, liver fibrosis, and hepatocyte apoptosis, with elevated Bax and decreased Bcl-2 expression, compared to the WT mice. Transcriptomic analysis of primary hepatocytes revealed that PERK was upregulated in Hamp ^−/− mice after CCl₄ treatment, promoting apoptosis by regulating Bax and Bcl-2 expression. Subsequently, we demonstrated that hepcidin prevents hepatocyte apoptosis by inhibiting PERK both in vitro and in vivo. Conclusions: Hepcidin inhibits hepatocyte apoptosis through suppression of the PERK pathway, highlighting its protective role in liver fibrosis and identifying a potential therapeutic target for the treatment of liver fibrosis.