FIG 5.

Bile acids activate PXR and VDR nuclear receptors upstream of P-gp induction. (A) Representative Western blot and densitometry of P-gp expression in T84 cells after 24 h incubation with rifampicin versus DMSO control. **, P < 0.01 by unpaired t test. (B) Representative Western blot and densitometry pooled from two independent experiments of P-gp expression in T84 cells after 24 h incubation with vitamin D3 versus DMSO control. *, P < 0.05 by one-way ANOVA with Dunnett’s multiple-comparison test. (C) qPCR analysis of ABCB1, CYP3A4, and CYP24A1 expression in T84 cells treated with compounds as shown for 4 h compared to DMSO control. One-way ANOVA with Dunnett’s multiple-comparison test, *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. (D) qPCR analysis of ABCB1 expression at baseline in Cas9 control and PXR KO T84 cells. *, P < 0.05 by unpaired t test. (E) qPCR analysis of ABCB1 expression in Cas9 control and PXR KO T84 cells after 4 h incubation with rifampicin or bile acids as indicated. One-way ANOVA with Dunnett’s multiple-comparison test performed for each cell line, *, P < 0.05; **, P < 0.01 for each condition versus DMSO vehicle control. (A-E) Representative data of at least two independent experiments. (F) Significantly enriched pathways (wikipathways) in butyrate-treated T84 cells determined by g:Profiler analysis of RNAseq data (Fig. 1).