Abstract: FR-PO244

The Role of TLR4 in Hepatitis B Virus X Protein Induced Immunity Disorder in Renal Tubular Epithelial Cells

Session Information

Category: Cell Biology

  • 202 Apoptosis, Proliferation, Autophagy, Cell Senescence, Cell Transformation

Author

  • Wang, Xuan, Shanghai Jiaotong University Affiliated First People''s Hospital, Shanghai, China
Background

Hepatitis B virus X protein could activate inflammatory immune response, which may contribute to the pathogenesis of HBV-GN. How HBx change the function of renal tubular epithelial cells(RTECs) was unknown. We want to explore the role of TLR4 in immunity disorder of RTECs mediated by HBx.

Methods

C57BL/6J-TgN mice(6 week old) were randomly divided into the experimental group and the intervention group. C57BL/6J mice were used as normal control group. Mice of the intervention group were injected TLR4 shRNA lenti virus from 8-week old, and injected every four weeks. Serum and urine were collected at 8, 12, 16, 20, 24-week old. Mice were sacrificed at 24 week old to observe the mice renal function and pathological changes. HBx and TLR4 expression in renal tissue were observed by immunohistochemistry, and macrophages and T cells were also detected by immunohistochemistry. We constructed a HBx-overexpression plasmid and a TLR4 shRNA plasmid and transfected them into human proximal tubular epithelial cell line(HK-2). Flow cytometry was used to investigate the expression of MHC-II, CD40 on HK-2 cells. Mixed lymphocyte reaction was used to ddetect the ability of stimulating T cells proliferation. IFN-gamma and IL-4 in supernatant were determined by ELISA.

Results

Proteinuria of C57BL/6J-TgN mice increased from 16-week old, and renal function deteriorated up to 24 week-old. HBx and TLR4 expression was observed in tubular epithelial cells of C57BL/6J-TgN mice, and they had significant interstitial CD4+ T cells and macrophages accumulation. Mice with TLR4 shRNA lenti virus intervention appeared reduced proteinuria and remission of renal function and fewer CD4+ T cells and macrophages infiltration. After transfection of HBx gene, the expressions of MHC-II and CD40 in HK-2 cells were up-regulated, and IFN-gamma/IL-4 ratio increased. TLR4 shRNA transfection down-reagulated expression of MHC-II and CD40 on renal tubular epithelial cells, decreased ability of stimulating T cell proliferation and lowered ratio of IFN-gamma/IL-4.

Conclusion

HBx could stimulate HK-2 cells MHC-II and CD40 expression, functioning as nonprofessional antigen-presenting cells, and activate inflammatory immune response, which may contribute to the pathogenesis of HBV-GN. Inhibiton of TLR4 can depress immune function of tubular epithelial cells and have prevention and treatment effect.