title: Pyrazole induced oxidative liver injury independent of CYP2E1/2A5 induction due to Nrf2 deficiency.
abstract: Pyrazole can induce CYP2E1 and 2A5, which produce reactive oxygen species (ROS). Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates important antioxidant enzymes to remove ROS. In this study, we applied Nrf2 knockout mice to test the hypothesis that pyrazole will cause hepatotoxicity and elevate oxidative stress to a greater extent in Nrf2 knockout mice compared to wild type mice. Pyrazole induced severe oxidative liver damage in Nrf2 knockout mice but not in wild type mice. Activities and levels of CYP2E1 and 2A5 were elevated by pyrazole in the wild type mice but not in the Nrf2 knockout mice. However, expression or activity of Nrf2-regulated antioxidant enzymes, such as gamma-glutamylcysteine synthetase (GCS), heme oxygenase-1 (HO-1) and glutathione-S-transferase (GST), were upregulated in the pyrazole-treated wild type mice, but to a lesser extent or not at all in the pyrazole-treated Nrf2 knockout mice. Treatment with antioxidants such as vitamin C or S-adenosyl-l-methionine (SAM) or an inhibitor of iNOS prevented the pyrazole-induced oxidative liver damage, thus validating the role of oxidative/nitrosative stress in the pyrazole induced liver injury to the Nrf2 knockout mice. In summary, even though ROS-producing CYP2E1/2A5 were not elevated by pyrazole, impaired antioxidant capacity resulting from Nrf2 deficiency appear to be sufficient to promote pyrazole-induced oxidative liver injury.
authors: Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors: Yongke
authors: Y
authors: Lu
authors: Pengfei
authors: P
authors: Gong
authors: Arthur I
authors: AI
authors: Cederbaum
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase / Q000378:metabolism; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis*; D001219:Aspartate Aminotransferases / Q000097:blood; D015153:Blotting, Western; D002374:Catalase / Q000378:metabolism; D056486:Chemical and Drug Induced Liver Injury / Q000201:enzymology* / Q000473:pathology*; D065637:Cytochrome P-450 CYP2A6; D019392:Cytochrome P-450 CYP2E1 / Q000096:biosynthesis*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007202:Indicators and Reagents; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000201:enzymology / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D051267:NF-E2-Related Factor 2 / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D011720:Pyrazoles / Q000494:pharmacology*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D007202:Indicators and Reagents; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D011720:Pyrazoles; D017392:Thiobarbituric Acid Reactive Substances; C031280:pyrazole; D002374:Catalase; D015660:7-Alkoxycoumarin O-Dealkylase; D019392:Cytochrome P-450 CYP2E1; D001189:Aryl Hydrocarbon Hydroxylases; D065637:Cytochrome P-450 CYP2A6; D005982:Glutathione Transferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D005978:Glutathione