title: Direct transcriptional regulation of human hepatic cytochrome P450 3A4 (CYP3A4) by peroxisome proliferator-activated receptor alpha (PPARα).
abstract: 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.
authors.affiliation: Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Auerbachstr. 112, 70376 Stuttgart, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Thomas
authors.forename: Oliver
authors.initials: O
authors.lastname: Burk
authors.forename: Britta
authors.initials: B
authors.lastname: Klumpp
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Kandel
authors.forename: Georg
authors.initials: G
authors.lastname: Damm
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Weiss
authors.forename: Kathrin
authors.initials: K
authors.lastname: Klein
authors.forename: Matthias
authors.initials: M
authors.lastname: Schwab
authors.forename: Ulrich M
authors.initials: UM
authors.lastname: Zanger
mesh_terms: D000818:Animals; D047369:Chromatin Immunoprecipitation / Q000379:methods; D051544:Cytochrome P-450 CYP3A / Q000235:genetics* / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D006801:Humans; D008024:Ligands; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D047493:PPAR alpha / Q000235:genetics* / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D011743:Pyrimidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics*
chemical_list: D008024:Ligands; D047493:PPAR alpha; D010743:Phospholipids; D011743:Pyrimidines; D012333:RNA, Messenger; C006253:pirinixic acid; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human