HBx gene accelerates cell proliferation and enhances inflammatory factors expression through ERK1/2 signaling pathway

Abstract

Objective To investigate the effects of HBx gene on hepatocyte cycle and immune system in vivo based on self-developed mouse model with stable expression of HBx gene. Methods Lentivirus carrying HBx gene were used to infect liver precursor cells 14-19. Then the modified liver precursor cells were injected into the portal vein of mice to construct the model. The model was identified with qRT-PCR, Western blot assay and immunohistochemistry. In 180 d after the model establishment, the mRNA and protein levels of cell cycle regulators CDK4 and Cyclin D1, TNF-α and IL-10 in the liver tissue were detected. While the protein levels of the proteins in the ERK1/2 and MEK1/2 signalling pathways were also measured. HE staining was used to observe the pathological changes in the liver tissue. Results The mouse model with stable expression of HBx gene was successfully constructed. Compared with the mice of normal saline group and the EGFP-14-19 group, in the mice in 180 d after the model establishment, HBx significantly up-regulated the mRNA (P < 0.01) and protein levels of CDK4, Cyclin D1 and TNF-α, but down-regulated the expression of IL-10 at both levels (P < 0.05). HBx significantly activated ERK1/2 signalling pathway. After the administration of ERK1/2 signal pathway inhibitor U0126, the mRNA and protein expression of CDK4, Cyclin D1, and TNF-α was significantly down-regulated in the experimental group than the control group (P < 0.05), but the mRNA and protein levels of IL-10 were in an opposite trend (P < 0.01). HE staining showed that the liver tissue had obvious pathological changes in the mouse model. Conclusion HBx accelerates cell proliferation and induces liver inflammation by activating ERK1/2 signaling pathway.

Keywords

• hbx
• erk1/2 signaling pathway
• cell cycle
• inflammation
• animal model