Fig. 3.

NF-κB p65 expression suppresses the transactivation of the BSEP, MRP2, FXR, and ABCG5-ABCG8 promoters. Huh-7 cells were transiently transfected with FXR/RXR and plasmid vectors containing the BSEP (A), MRP2 (C), FXR (D), or ABCG5-ABCG8 (B) promoter sequences that included the NF-κBE linked to luciferase as reporter. FXR transactivation of the promoter constructs was monitored by luciferase activity. As expected, transfection with FXR/RXR in the presence of the FXR ligand GW4064 led to a marked transactivation of these promoters (A–D). In contrast, NF-κB p65 overexpression (50 ng) markedly repressed ligand-induced FXR/RXR transactivation of the BSEP and ABCG5/G8 promoters, which was totally reversed by expression of the IκBα super-repressor. RLU, relative light units. #P < 0.05.