Work

Rifampin modulation of xeno‐ and endobiotic conjugating enzyme mRNA expression and associated micro RNA s in human hepatocytes

Year: 2018

Type: article

Abstract: Rifampin is a pleiotropic inducer of multiple drug metabolizing enzymes and transporters. This work utilized a global approach to evaluate rifampin effects on conjugating enzyme gene expression with relevance to human xeno‐ and endo‐biotic metabolism. Primary human hepatocytes from 7 subjects were treated with rifampin (10 μmol/L, 24 hours). Standard methods forRNA‐seq library construction,EZBead preparation, and NextGen sequencing were used to measure UDP‐glucuronosyl transferaseUGT, sulfonyltransferaseSULT, N acetyltransferaseNAT, and glutathione‐S‐transferaseGST mRNAexpression compared to vehicle control (0.01% MeOH). Rifampin‐induced (>1.25‐fold)mRNAexpression of 13 clinically important phaseIIdrug metabolizing genes and repressed (>1.25‐fold) the expression of 3 genes (P < .05). Rifampin‐induced miRNAexpression changes correlated withmRNAchanges and miRNAs were identified that may modulate conjugating enzyme expression.NAT2 gene expression was most strongly repressed (1.3‐fold) by rifampin whileUGT1A4 andUGT1A1 genes were most strongly induced (7.9‐ and 4.8‐fold, respectively). Physiologically based pharmacokinetic modeling (PBPK) was used to simulate the clinical consequences of rifampin induction ofCYP3A4‐ andUGT1A4‐mediated midazolam metabolism. Simulations evaluating isolatedUGT1A4 induction predicted increased midazolam N‐glucuronide exposure (~4‐fold) with minimal reductions in parent midazolam exposure (~10%). Simulations accounting for simultaneous induction of bothCYP3A4 andUGT1A4 predicted a ~10‐fold decrease in parent midazolam exposure with only a ~2‐fold decrease in midazolam N‐glucuronide metabolite exposure. These data reveal differential effects of rifampin on the human conjugating enzyme transcriptome and potential associations with miRNAs that form the basis for future mechanistic studies to elucidate the interplay of conjugating enzyme regulatory elements.

Source: Pharmacology Research & Perspectives

DOI: 10.1002/prp2.386