[The expression and role of Toll receptor 4 in renal tubular epithelial cells in hepatitis B virus infection].

OBJECTIVE

To explore the expression and role of Toll receptor 4 (TLR4) in human proximal tubular epithelial cell line HK-2, infected by HBV.

METHODS

The serum of HBV DNA copies between 10(7) - 10(8)/ml was collected. Before and after infected by HBV DNA positive serum, the HK-2 cells' morphology and the expression of α-smooth muscle actin (α-SMA) were observed by microscopy and immunofluorescence, and the effects of different concentrations of lipopolysaccharides (LPS, TLR4-stimulating factor) and CLI-095 (TLR4 Inhibitor) on the proliferation rate of HK-2 cells were observed by MTT assays. After HBV serum and 10 µg/ml LPS and 5 µl/ml CLI-095 acted on HK-2 cells, TLR4 protein expression was measured by immunofluorescence and Western-blotting assay, and HBsAg and HBeAg in cell culture medium were detected by ELISA, and HBV DNA copies by fluorescence quantitative PCR.

RESULTS

The longer HBV infected HK-2 cells, the more irregular of the cells' shape, the fewer number of the cells were left. But compared with HBV infected after 24 hours, α-SMA was more expressed after HBV infected 12 hours.After infected by HBV serum in 24 hours, HK-2 cells' proliferation rate was positively correlation in a dose range of LPS, but was negatively correlated with the CLI-095 (P < 0.05). The levels of HBsAg and HBeAg in cell culture medium were largest when the LPS concentration was at 10 µg/ml and CLI-095 at 5 µg/ml. The expression of TLR4 significantly increased in HK-2 cells treated with LPS compared with those with CLI-095, but HBV DNA levels and HBsAg and HBeAg expression levels were lower.

CONCLUSIONS

HBV infection may promote cell transdifferentiation and cell injury. The stimulation of HK-2 infected with HBV by LPS may upregulate the expression of TLR4 and reduce the copies of HBV DNA.