Mechanism on hepatitis B virus X gene-induced hepatic steatosis

Abstract

Objective To investigate the effect of liver X receptor α(LXRα) gene silencing on lipid metabolism-related genes in HepG2.2.15 cells.Methods HepG2.2.15 cells were divided into blank control group(without transfection),negative control group(transfected with HK plasmid),and shLXRα group(transfected with shLXRα plasmid).The shLXRα plasmids carrying LXRα gene were constructed and were used to transfect HepG2.2.15 cells using PolyJetTM reagent.Green fluorescent protein and LXRα protein expression were examined by fluorescence microscope and Western blotting analysis 24-96 h after transfection,so as to identify the best interference time.Then cells were treated with agonist T0901317 for 24 h or 48 h;and the content of triglyceride(TG) was observed to detect the degree of steatosis by biochemical assay.The expression of sterol regulatory element binding protein-1c(SREBP-1c) mRNA was detected by RT-PCR and the expression of hepatitis B virus X(HBx) protein and fatty acid synthase(FAS) protein was tested by Western blotting analysis.Results The shLXRα plasmid was constructed and transfected into HepG2.2.15 cells successfully.Compared with blank and negative control groups,LXRα protein was markedly decreased in the shLXRα group,with the lowest level found at 48-72 h after transfection(P0.01).After cells were stimulated with T0901317,HBx and FAS protein expression,the content of TG,and SREBP-1c mRNA expression gradually increased with the prolongation of stimulation period,and there was no significant difference in HBx expression at the same time point between different groups.FAS protein,TG contents,and SREBP-1c mRNA in shLXRα group were significantly lower than those in the other two groups(P0.01).Conclusion HBx can regulate lipid metabolism through LXRα/SREBP-1c/FAS pathway.