HBX inhibits the expression of high-mobility group protein box 1 and the generation of reactive oxygen species via nuclear factor-κB signaling pathway

Abstract

Objective This study focus on the effect of HBX on the expression of HMGB1 in vitro. Methods we overexpress the HBX protein in LO2 cell (a normal hepatocyte cell line). Then the activity of nuclear factor (NF)-κB, the expression of HMGB1 and the generation of ROS were detected by Western blotting and 2’, 7’-dichlorodihydrofluorescin diacetate (DCFH-DA) (ROS detector) staining. Afterwards, retenone and lipopolysaccharide (LPS), which were the activor of ROS and NF-κB separately, were used to stimulate the HBX-overexpressed cells and the expressed differentiation of, HMGB1 and ROS or the activity alternation of NF-κB were detected again. Results The results of Western blotting indicated that HBX significantly inhibited expression of HMGB1 (more than 2.4 fold, P=0.025), ROS and the phosphorylation levels of p65 and IκB. For further confirm these results, we stimulated the LO2-HBX cell, which are the stimulators of ROS and NF-κB, respectively. And the results suggested that the phosphorylation levels of p65 and IκB were enhanced after stimulation. All of these results revealed that the NF-κB and HMGB1 could directly regulate each other. Conclusion HBX inhibits the expression of HMGB1 and the generation of ROS via NF-κB signaling pathway. Key words: Hepatitis B virus X protein; Nuclear factor-κB; High-mobility group protein box 1; Reactive oxygen species