Figure 5.

Interaction of 20S(OH)D₃, 20S,25(OH)₂D₃, 20S,23S(OH)₂D₃ and 20S,23R(OH)₂D₃ with nuclear receptors. A: ligand induced translocation of the VDR-GFP from the cytoplasm to nucleus. B: stimulation of AhR binding activity by secosteroids using AhR Reporter Cells including the luciferase reporter gene linked to an AhR-responsive promoter (Indigo Biosciences, State College, PA). C: ligand induced stimulation of CYP24A1 gene expression after 8 h of incubation. D: ligand stimulated expression of CYP1A1 and CYP1B1 genes. E: LXRα. F: LXRβ binding assay using LanthaScreen TR-FRET coactivator kit (Thermo Fisher Scientific, Inc., Waltham, MA). Data represent means ± SE where *p < 0.05, **p < 0.01, ***p < 0.001 and ****p < 0.0001 at student t-test; #p < 0.05, ##p < 0.01, ###p < 0.001 and ####p < 0.0001 at one way ANOVA. For A (n ≥ 4), B (n = 3), C and D (n = 3), E and F (n = 4). Gene expression was measured after 8 h of keratinocytes treatment with secosteroids and presented as fold change vs ethanol (0.1%) control and with GADPH (C) and cyclophilin (D) serving as internal controls.