FXR and FXR-dependent genes (SOCS3 and DDAH1) are expressed in tubular cells. (A) Predominant tubulointerstitial expression of FXR (NR1H4), SOCS3, and DDAH1 in the Woroniecka cohort of the Nephroseq database. (B and C) Predominant tubular expression of the FXR-dependent genes SOCS3 and DDAH1; immunofluorescence analyses of SOCS3 and DDAH1 (red; nuclear DAPI counterstain, blue) in nondiabetic human kidney biopsy samples (B) and murine kidney sections [decibels per meter (C)]. (D) Expression of SOCS3 and DDAH1 is readily detectable at baseline (control, C) and is further increased by TUDCA (T; 500 μM, 24 hours) specifically in human tubular cells (HKC-8) but not in endothelial cells (EA.hy926), podocytes (h.Podo), or mesangial cells (h.MC). (E) shRNA lentiviral–mediated knockdown of FXR expression (FXRKD) in tubular cells (HKC-8) averts the TUDCA-mediated induction of FXR-dependent genes (SOCS3 and DDAH1) compared with nontransduced cells (C) or cells transduced with scrambled shRNA (Scr). Representative immunoblots (bottom, D and E) and bar graphs (top, D and E) summarizing results. Bar graphs showing mean±SEM obtained from three independent repeat experiments each with three disjunct replicates. Scale bar, 20 μm (B and C); glomeruli indicated by white dashed circles (B and C); *P<0.05; **P<0.01 (one-way ANOVA).