RT Journal Article SR Electronic T1 Direct Transcriptional Regulation of Human Hepatic Cytochrome P450 3A4 (CYP3A4) by Peroxisome Proliferator–Activated Receptor Alpha (PPARα) JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 709 OP 718 DO 10.1124/mol.112.082503 VO 83 IS 3 A1 Maria Thomas A1 Oliver Burk A1 Britta Klumpp A1 Benjamin A. Kandel A1 Georg Damm A1 Thomas S. Weiss A1 Kathrin Klein A1 Matthias Schwab A1 Ulrich M. Zanger YR 2013 UL http://molpharm.aspetjournals.org/content/83/3/709.abstract AB The nuclear receptor peroxisome proliferator–activated receptor (PPAR)α is known primarily as a regulator of fatty acid metabolism, energy balance, and inflammation, but evidence suggests a wider role in regulating the biotransformation of drugs and other lipophilic chemicals. We investigated whether PPARα directly regulates the transcription of cytochrome P450 3A4, the major human drug-metabolizing enzyme. Using chromatin immunoprecipitation in human primary hepatocytes as well as electrophoretic mobility shift and luciferase reporter-gene assays, we identified three functional PPARα-binding regions (PBR-I, -II, and -III) within ∼12 kb of the CYP3A4 upstream sequence. Furthermore, a humanized CYP3A4/3A7 mouse model showed in vivo induction of CYP3A4 mRNA and protein by [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio]acetic acid (WY14,643) in liver but not in intestine, whereas hepatic occupancy of PBRs by PPARα was ligand independent. Using lentiviral gene knock-down and treatment with WY14,643 in primary human hepatocytes, PPARα was further shown to affect the expression of a distinct set of CYPs, including 1A1, 1A2, 2B6, 2C8, 3A4, and 7A1, but not 2C9, 2C19, 2D6, or 2E1. Interestingly, the common phospholipid 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine (16:0/18:1-PC), previously proposed to reflect nutritional status and shown to be a specific endogenous ligand of PPARα, induced CYP3A4 (up to 4-fold) and other biotransformation genes in hepatocytes with similar selectivity and potency as WY14,643. These data establish PPARα as a direct transcriptional regulator of hepatic CYP3A4. This finding warrants investigation of both known and newly developed PPARα-targeted drugs for their drug-drug interaction potential. Furthermore, our data suggest that nutritional status can influence drug biotransformation capacity via endogenous phospholipid signaling.