Detailing the immune response to TGFB2 in cholestatic liver disease of PSC patients and MDR2KO mice

Primary sclerosing cholangitis (PSC) and the MDR2KO mouse model are characterized by chronic cholestatic liver inflammation and fibrosis. Silencing of transforming growth factor-beta 2 (TGF-β2), a known driver of fibrosis, has shown a decrease of CD45+cells, an increase of F4/80+cells and CD8+T cells, and recruitment of eosinophils in the livers of MDR2KO mice, implicating a key immunomodulatory role in this context. This project aims to delineate the specific mechanisms involved upon TGF-β2 treatment in regulating immune cell behavior in biliary liver disease.

TGF-β2 conjugated to AAV8 was administered to MDR2KO and wild type mice aged 12 weeks. After 7 days, immune cell phenotyping of the livers was performed using multicolor FACS and immunohistochemistry analysis, focusing on key lymphoid and myeloid populations. RNAScope was performed to localize and quantify eosinophils. In vitro, the impact of TGF-β2 on differentiation of human T cell subsets was examined using FACS analysis. Furthermore, TGF-β2 effects on T cell proliferation and apoptosis were monitored with real-time imaging.

Blood analysis revealed elevated ALT and AST levels in wild type and MDR2KO mice treated with AAV8-TGF-β2, suggesting an increased cell damage by TGF-β2. Interestingly, triglyceride levels decreased in both wild type and MDR2KO mice treated with TGF-β2, indicating an influence on lipid metabolism. In MDR2KO mice, eosinophils were predominantly located around the portal triads and in fibrotic regions. Treatment of T cells with TGF-β2 increased the expression of CD25, a marker for T cell activation and Tregs, as well as CD69 and CD154. The effects were more pronounced with TGF-β2 as compared to TGF-β1, indicating distinct and nuanced differential signaling. Despite reduced apoptosis compared to naïve cells, the TGF-β2-treated group showed decreased cell numbers and proliferation, suggesting impaired expansion or altered survival dynamics.

FACS data are currently undergoing analysis to further characterize immune cell subsets and validate preliminary observations. These analyses will be extended to monocytic cell cultures and human liver tissues from PSC, PBC, and CCA patients to enhance translational relevance.

These preliminary results indicate that TGF-β2 contributes to liver damage, promotes T cell differentiation, and regulates T cell behavior, thereby helping to elucidate its role in modulating immune competence and disease progression in cholestatic liver disease.

 

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Artikel online veröffentlicht:
04. September 2025