title: Drug metabolizing enzyme induction pathways in experimental non-alcoholic steatohepatitis.
abstract: Non-alcoholic steatohepatitis (NASH) is a disease that compromises hepatic function and the capacity to metabolize numerous drugs. Aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor alpha (PPARalpha), and nuclear factor-E2 related factor 2 (Nrf2) are xenobiotic activated transcription factors that regulate induction of a number of drug metabolizing enzymes (DMEs). The purpose of the current study was to determine whether experimental NASH alters the xenobiotic activation of these transcription factors and induction of downstream DME targets Cyp1A1, Cyp2B10, Cyp3A11, Cyp4A14 and NAD(P)H:quinone oxidoreductase 1 (Nqo1), respectively. Mice fed normal rodent chow or methionine-choline-deficient (MCD) diet for 8 weeks were then treated with microsomal enzyme inducers beta-naphoflavone (BNF), 1,4-bis-[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP), pregnenolone-16alpha-carbonitrile (PCN), clofibrate (CFB) or oltipraz (OPZ), known activators of AhR, CAR, PXR, PPARalpha and Nrf2, respectively. Results of this study show that (1) Hepatic PXR mRNA levels were significantly increased (1.4-fold) in mice fed MCD diet, while AhR, CAR, PPARalpha and Nrf2 were not affected. (2) The MCD diet did not alter hepatic inducibility of Cyp1A1, Cyp2B10, Cyp3A11 mRNA levels by their respective microsomal inducers. (3) Constitutive levels of Cyp4A14 mRNA were significantly increased in mice fed the MCD diet, yet further induction by clofibrate was not observed. (4) Hepatic Nqo1 mRNA levels were significantly increased by the MCD diet; however, additional induction of Nqo1 was still achievable following treatment with the Nrf2 activator OPZ.
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, 1703 East Mabel, Tucson, AZ 85721, USA. cfisher@pharmacy.arizona.edu
authors.forename: Craig D
authors.initials: CD
authors.lastname: Fisher
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Jackson
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Lickteig
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Augustine
authors.forename: Nathan J
authors.initials: NJ
authors.lastname: Cherrington
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis* / Q000235:genetics; D000090702:Constitutive Androstane Receptor; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis* / Q000235:genetics; D051544:Cytochrome P-450 CYP3A / Q000096:biosynthesis* / Q000235:genetics; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics; D000072467:Cytochrome P450 Family 2; D000072470:Cytochrome P450 Family 4; D004790:Enzyme Induction / Q000187:drug effects; D005234:Fatty Liver / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D016660:NAD(P)H Dehydrogenase (Quinone); D009252:NADPH Dehydrogenase / Q000096:biosynthesis* / Q000235:genetics; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism; D047493:PPAR alpha / Q000235:genetics / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D000077297:Pregnane X Receptor; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000096:biosynthesis* / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D000090702:Constitutive Androstane Receptor; C436963:Cyp4a14 protein, mouse; D008565:Membrane Proteins; D051267:NF-E2-Related Factor 2; D047493:PPAR alpha; D004364:Pharmaceutical Preparations; D000077297:Pregnane X Receptor; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D014157:Transcription Factors; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C101679:Cyp2b10 protein, mouse; C496508:Cyp3a11 protein, mouse; D019363:Cytochrome P-450 CYP1A1; D051544:Cytochrome P-450 CYP3A; D000072467:Cytochrome P450 Family 2; D000072470:Cytochrome P450 Family 4; D016660:NAD(P)H Dehydrogenase (Quinone); C491732:Nqo1 protein, mouse; D009252:NADPH Dehydrogenase