Figure 4. HBx inhibits CYP2E1 expression via downregulation of HNF4α.

(A) HBV virus downregulated HNF4α and CYP2E1. HepG2215 cells, a cell line with the HBV genome integrated into the chromosome of HepG2 cells and capable of producing all HBV proteins, was used. Expression of HBx, CYP2E1 and HNF4α levels were measured with Western blotting. (B) Enforced expression of HBx protein downregulates CYP2E1 and HNF4α. HepG2 cells were transiently transfected with HBx-expression plasmid, and 24 hours post transfection, cells were harvested and cell lysate were used to determine HNF4α expression with Western Blotting. (C) HBx-induced CYP2E1 reduction could be rescued by HNF4α. HepG2 cells were transiently transfected with HBx-expression plasmid for 24 hours, then were infected with 1×10⁹ plaque-forming units of AdHNF4α, or the same amount of AdGFP as control for one more day, respectively, in HepG2 cells. Cells were harvested and protein expression of HBx, CYP2E1 and HNF4α levels were measured with Western blotting.