Fig. 1.

Urolithin A (UroA) augments 1,25D-triggered transcriptional activation mediated by a range (0.1 nM–10 nM) of concentrations of 1,25D. For all four panels, fold-effect of 1,25D or 1,25D + UroA above vehicle control is listed at the top of the appropriate bar. The UroA fold-potentiation of the 1,25D-effect is depicted in white text on a black background. Values are the average of nine biological replicates (n = 9) ± Std. Dev. (A) Effect of UroA on transcriptional activation driven by the XDR3 VDRE in HEK293 cells treated with 10 nM 1,25D. Cells were exposed in culture to either EtOH/DMSO vehicle or a final concentration of 10 nM 1,25D (alone), 20 μM UroA (alone), or both 1,25D and UroA for 24 h and transcription assessed by luciferase activity as described in Methods. (B) Effect of UroA on transcriptional activation driven by the XDR3 VDRE in HEK293 cells treated with 1,25D. Cells were exposed in culture to either EtOH/DMSO vehicle or a final concentration of 1 nM 1,25D (alone), 20 μM UroA (alone), or both 1,25D and UroA for 24 h and transcription assessed by luciferase activity as described in Methods. (C) Effect of UroA on transcriptional activation driven by the XDR3 VDRE in HEK293 cells treated with 1,25D. Cells were exposed in culture to either EtOH/DMSO vehicle or a final concentration of 0.5 nM 1,25D (alone), 20 μM UroA (alone), or both 1,25D and UroA for 24 h and transcription assessed by luciferase activity as described in Methods. (D) Effect of UroA on transcriptional activation driven by the XDR3 VDRE in HEK293 cells treated with 1,25D. Cells were exposed in culture to either EtOH/DMSO vehicle or a final concentration of 0.1 nM 1,25D (alone), 20 μM UroA (alone), or both 1,25D and UroA for 24 h and transcription assessed by luciferase activity as described in Methods.