Figure 1.

FXR activates the transcription of SR-BI via the FXRE motif located in the first intron of the hamster SR-BI gene. (A) Schematic presentation of luciferase reporter constructs with intronic sequences of the hamster SR-BI gene. (B) Reporter constructs were transiently cotransfected with pCMV-β-gal vector into HepG2 cells with four wells per condition. At 1 day post-transfection, cells were incubated in 0.5% fetal bovine serum medium overnight, followed by treatment with GW4064 (1 µM) or OCA (10 µM) for 24 h. Cells were harvested, and the luciferase and β-gal activities were measured. Following normalization, relative luciferase activity of transfected cells treated with vehicle DMSO is expressed as 1. Statistical significance among all groups was assessed by one-way ANOVA with Tukey's multiple comparison test. ^**P<0.01 and ^***P<0.001 between control and ligand-treated group. (C) Data are summarized results (mean ± standard error of the mean) of four independent transfection assays. Following normalization, relative luciferase activity of transfected cells treated with vehicle DMSO is expressed as 1. Statistical significance among all groups was assessed by one-way ANOVA with Tukey's multiple comparison test. ^**P<0.01 and ^***P<0.001 compared with the inducing effects of OCA or GW4064 on control vector pGL4.23. FXR, farnesoid X receptor; FXRE, FXR response element; SR-BI, scavenger receptor class B type I; β-gal, β-galactosidase; OCA, obeticholic acid; ANOVA, analysis of variance; n.s., not significant.