Effects of hepatitis B virus X gene on apoptosis and expression of immune molecules of human proximal tubular epithelial cells.

The hepatitis B virus X protein (HBx) is the most important determinant in viral pathogenesis. HBx regulates HBV replication, cellular transcription, signal transduction, proteasome activity and cell cycle progression. In this study, HK-2 cells were transiently transfected with the HBx gene using a eukaryotic vector, pcDNA3.1/myc-HBx. Transfection with the HBx gene increased the number of apoptotic cells. In addition, cultured HK-2 cells became irregular in shape. The expression of α-SMA and E-cadherin, TLR4, MHC-II and CD40 was increased. The transfection resulted in increased IL-1, IL-6, TNF-α and IFN-γ levels in the supernatant and decreased IL-4 in the supernatant. In conclusion, overexpression of the HBx gene in renal tubular epithelial cells induces apoptosis of HK-2 cells and promotes epithelial-mesenchymal transdifferentiation. HBx transfection upregulates the expression of immune molecules in renal tubular epithelial cells and induces an imbalance in cytokine levels.