RT Journal Article
SR Electronic
T1 Negative Regulation of Human Pregnane X Receptor by MicroRNA-18a-5p: Evidence for Suppression of MicroRNA-18a-5p Expression by Rifampin and Rilpivirine
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP mol.116.107003
DO 10.1124/mol.116.107003
A1 Devinder Sharma
A1 Abdullah A. Turkistani
A1 Wenjun Chang
A1 Catherine Hu
A1 Zhaoming Xu
A1 Thomas K. H. Chang
YR 2017
UL http://molpharm.aspetjournals.org/content/early/2017/04/13/mol.116.107003.abstract
AB Small non-coding microRNAs act as post-transcriptional regulators of gene expression involved in diverse biological functions. Pregnane X receptor (PXR, NR1I2), which is a member of the superfamily of nuclear receptors, is a transcription factor governing the transport and biotransformation of various endobiotics and xenobiotics. In the present study, we identified a specific microRNA involved in regulating the expression and functionality of human PXR (hPXR). According to bioinformatics analysis employing three commonly used algorithms (TargetScan, miRanda, and DIANA-microT-CDS), miR-18a-5p was predicted to be the top candidate microRNA regulator of hPXR. Consequently, this microRNA was selected for detailed experimental investigation. As shown in cell-based dual-luciferase reporter gene assays, functional interaction occurred between miR-18a-5p and the microRNA recognition element of miR-18a-5p in the 3'-untranslated region of hPXR mRNA. Transfection of LS180 human colorectal adenocarcinoma cells with a miR-18a-5p mimic decreased hPXR mRNA and protein expression, whereas transfection of LS180 cells with a miR-18a-5p inhibitor increased hPXR mRNA and protein expression. The decrease in hPXR expression by the miR-18a-5p mimic was associated with a reduction in the extent of hPXR target gene (CYP3A4) induction by rifampin and rilpivirine. Treatment of untransfected LS180 cells with either of these hPXR agonists decreased endogenous expression of miR-18a-5p, and this preceded the onset of CYP3A4 induction. In conclusion, miR-18a-5p is a negative regulator of hPXR expression and the hPXR agonists rifampin and rilpivirine are chemical suppressors of miR-18a-5p expression.