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Kim YS, Ko B, Kim DJ, Tak J, Han CY, Cho JY, Kim W, Kim SG. Induction of the hepatic aryl hydrocarbon receptor by alcohol dysregulates autophagy and phospholipid metabolism via PPP2R2D. Nat Commun 2022; 13:6080. [PMID: 36241614 PMCID: PMC9568535 DOI: 10.1038/s41467-022-33749-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 09/30/2022] [Indexed: 12/24/2022] Open
Abstract
Disturbed lipid metabolism precedes alcoholic liver injury. Whether and how AhR alters degradation of lipids, particularly phospho-/sphingo-lipids during alcohol exposure, was not explored. Here, we show that alcohol consumption in mice results in induction and activation of aryl hydrocarbon receptor (AhR) in the liver, and changes the hepatic phospho-/sphingo-lipids content. The levels of kynurenine, an endogenous AhR ligand, are elevated with increased hepatic tryptophan metabolic enzymes in alcohol-fed mice. Either alcohol or kynurenine treatment promotes AhR activation with autophagy dysregulation via AMPK. Protein Phosphatase 2 Regulatory Subunit-Bdelta (Ppp2r2d) is identified as a transcriptional target of AhR. Consequently, PPP2R2D-dependent AMPKα dephosphorylation causes autophagy inhibition and mitochondrial dysfunction. Hepatocyte-specific AhR ablation attenuates steatosis, which is associated with recovery of phospho-/sphingo-lipids content. Changes of AhR targets are corroborated using patient specimens. Overall, AhR induction by alcohol inhibits autophagy in hepatocytes through AMPKα, which is mediated by Ppp2r2d gene transactivation, revealing an AhR-dependent metabolism of phospho-/sphingo-lipids.
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Affiliation(s)
- Yun Seok Kim
- grid.31501.360000 0004 0470 5905Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, 03080 Korea ,grid.31501.360000 0004 0470 5905Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080 Republic of Korea ,grid.31501.360000 0004 0470 5905College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Bongsub Ko
- grid.31501.360000 0004 0470 5905Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, 03080 Korea
| | - Da Jung Kim
- grid.31501.360000 0004 0470 5905Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, 03080 Korea ,grid.412484.f0000 0001 0302 820XMetabolomics Core Facility, Department of Transdisciplinary Research and Collaboration, Biomedical Research Institute, Seoul National University Hospital, Seoul, 03082 Korea
| | - Jihoon Tak
- grid.31501.360000 0004 0470 5905College of Pharmacy, Seoul National University, Seoul, Republic of Korea ,grid.255168.d0000 0001 0671 5021College of Pharmacy and Integrated Research Institute for Drug Development, Dongguk University-Seoul, Goyang-si, Kyeonggi-do 10326 Republic of Korea
| | - Chang Yeob Han
- grid.31501.360000 0004 0470 5905College of Pharmacy, Seoul National University, Seoul, Republic of Korea ,grid.411545.00000 0004 0470 4320School of Pharmacy and Institute of New Drug Development, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do, 54896 Korea
| | - Joo-Youn Cho
- grid.31501.360000 0004 0470 5905Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, 03080 Korea ,grid.31501.360000 0004 0470 5905Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080 Republic of Korea
| | - Won Kim
- grid.31501.360000 0004 0470 5905Division of Gastroenterology and Hepatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea
| | - Sang Geon Kim
- grid.255168.d0000 0001 0671 5021College of Pharmacy and Integrated Research Institute for Drug Development, Dongguk University-Seoul, Goyang-si, Kyeonggi-do 10326 Republic of Korea
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Kawase A, Mukai H, Tateishi S, Kuroda S, Kazaoka A, Satoh R, Shimada H, Sugiura R, Iwaki M. Protein Kinase N Family Negatively Regulates Constitutive Androstane Receptor-Mediated Transcriptional Induction of Cytochrome P450 2b10 in the Livers of Mice. J Pharmacol Exp Ther 2021; 379:53-63. [PMID: 34312179 DOI: 10.1124/jpet.121.000790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 07/22/2021] [Indexed: 01/04/2023] Open
Abstract
In receptor-type transcription factors-mediated cytochrome P450 (P450) induction, few studies have attempted to clarify the roles of protein kinase N (PKN) in the transcriptional regulation of P450s. This study aimed to examine the involvement of PKN in the transcriptional regulation of P450s by receptor-type transcription factors, including the aryl hydrocarbon receptor, constitutive androstane receptor (CAR), and pregnane X receptor. The mRNA and protein levels and metabolic activity of P450s in the livers of wild-type (WT) and double-mutant (D) mice harboring both PKN1 kinase-negative knock-in and PKN3 knockout mutations [PKN1 T778A/T778A; PKN3 -/-] were determined after treatment with activators for receptor-type transcription factors. mRNA and protein levels and metabolic activity of CYP2B10 were significantly higher in D mice treated with the CAR activator phenobarbital (PB) but not with 1,4-bis((3,5-dichloropyridin-2-yl)oxy)benzene compared with WT mice. We examined the CAR-dependent pathway regulated by PKN after PB treatment because the extent of CYP2B10 induction in WT and D mice was notably different in response to treatment with different CAR activators. The mRNA levels of Cyp2b10 in primary hepatocytes from WT and D mice treated with PB alone or in combination with Src kinase inhibitor 1 (SKI-1) or U0126 (a mitogen-activated protein kinase inhibitor) were evaluated. Treatment of hepatocytes from D mice with the combination of PB with U0126 but not SKI-1 significantly increased the mRNA levels of Cyp2b10 compared with those from the corresponding WT mice. These findings suggest that PKN may have inhibitory effects on the Src-receptor for activated C kinase 1 (RACK1) pathway in the CAR-mediated induction of Cyp2b10 in mice livers. SIGNIFICANCE STATEMENT: This is the first report of involvement of PKN in the transcriptional regulation of P450s. The elucidation of mechanisms responsible for induction of P450s could help optimize the pharmacotherapy and improve drug development. We examined whether the mRNA and protein levels and activities of P450s were altered in double-mutant mice harboring both PKN1 kinase-negative knock-in and PKN3 knockout mutations. PKN1/3 negatively regulates CAR-mediated induction of Cyp2b10 through phosphorylation of a signaling molecule in the Src-RACK1 pathway.
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Affiliation(s)
- Atsushi Kawase
- Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka, Japan (A.Kaw., S.T., S.K., A.Kaz., H.S., M.I.); Biosignal Research Center, Kobe University, Hyogo, Japan (H.M.); Department of Clinical Laboratory, Kitano Hospital, Osaka, Japan (H.M.); Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka, Japan (R.Sa., R.Su.); Pharmaceutical Research and Technology Institute, Kindai University, Osaka, Japan (R.Su., M.I.); and Antiaging Center, Kindai University, Osaka, Japan (R.Su., M.I.)
| | - Hideyuki Mukai
- Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka, Japan (A.Kaw., S.T., S.K., A.Kaz., H.S., M.I.); Biosignal Research Center, Kobe University, Hyogo, Japan (H.M.); Department of Clinical Laboratory, Kitano Hospital, Osaka, Japan (H.M.); Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka, Japan (R.Sa., R.Su.); Pharmaceutical Research and Technology Institute, Kindai University, Osaka, Japan (R.Su., M.I.); and Antiaging Center, Kindai University, Osaka, Japan (R.Su., M.I.)
| | - Shunsuke Tateishi
- Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka, Japan (A.Kaw., S.T., S.K., A.Kaz., H.S., M.I.); Biosignal Research Center, Kobe University, Hyogo, Japan (H.M.); Department of Clinical Laboratory, Kitano Hospital, Osaka, Japan (H.M.); Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka, Japan (R.Sa., R.Su.); Pharmaceutical Research and Technology Institute, Kindai University, Osaka, Japan (R.Su., M.I.); and Antiaging Center, Kindai University, Osaka, Japan (R.Su., M.I.)
| | - Shintaro Kuroda
- Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka, Japan (A.Kaw., S.T., S.K., A.Kaz., H.S., M.I.); Biosignal Research Center, Kobe University, Hyogo, Japan (H.M.); Department of Clinical Laboratory, Kitano Hospital, Osaka, Japan (H.M.); Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka, Japan (R.Sa., R.Su.); Pharmaceutical Research and Technology Institute, Kindai University, Osaka, Japan (R.Su., M.I.); and Antiaging Center, Kindai University, Osaka, Japan (R.Su., M.I.)
| | - Akira Kazaoka
- Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka, Japan (A.Kaw., S.T., S.K., A.Kaz., H.S., M.I.); Biosignal Research Center, Kobe University, Hyogo, Japan (H.M.); Department of Clinical Laboratory, Kitano Hospital, Osaka, Japan (H.M.); Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka, Japan (R.Sa., R.Su.); Pharmaceutical Research and Technology Institute, Kindai University, Osaka, Japan (R.Su., M.I.); and Antiaging Center, Kindai University, Osaka, Japan (R.Su., M.I.)
| | - Ryosuke Satoh
- Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka, Japan (A.Kaw., S.T., S.K., A.Kaz., H.S., M.I.); Biosignal Research Center, Kobe University, Hyogo, Japan (H.M.); Department of Clinical Laboratory, Kitano Hospital, Osaka, Japan (H.M.); Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka, Japan (R.Sa., R.Su.); Pharmaceutical Research and Technology Institute, Kindai University, Osaka, Japan (R.Su., M.I.); and Antiaging Center, Kindai University, Osaka, Japan (R.Su., M.I.)
| | - Hiroaki Shimada
- Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka, Japan (A.Kaw., S.T., S.K., A.Kaz., H.S., M.I.); Biosignal Research Center, Kobe University, Hyogo, Japan (H.M.); Department of Clinical Laboratory, Kitano Hospital, Osaka, Japan (H.M.); Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka, Japan (R.Sa., R.Su.); Pharmaceutical Research and Technology Institute, Kindai University, Osaka, Japan (R.Su., M.I.); and Antiaging Center, Kindai University, Osaka, Japan (R.Su., M.I.)
| | - Reiko Sugiura
- Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka, Japan (A.Kaw., S.T., S.K., A.Kaz., H.S., M.I.); Biosignal Research Center, Kobe University, Hyogo, Japan (H.M.); Department of Clinical Laboratory, Kitano Hospital, Osaka, Japan (H.M.); Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka, Japan (R.Sa., R.Su.); Pharmaceutical Research and Technology Institute, Kindai University, Osaka, Japan (R.Su., M.I.); and Antiaging Center, Kindai University, Osaka, Japan (R.Su., M.I.)
| | - Masahiro Iwaki
- Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka, Japan (A.Kaw., S.T., S.K., A.Kaz., H.S., M.I.); Biosignal Research Center, Kobe University, Hyogo, Japan (H.M.); Department of Clinical Laboratory, Kitano Hospital, Osaka, Japan (H.M.); Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka, Japan (R.Sa., R.Su.); Pharmaceutical Research and Technology Institute, Kindai University, Osaka, Japan (R.Su., M.I.); and Antiaging Center, Kindai University, Osaka, Japan (R.Su., M.I.)
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Olivero-Verbel J, Harkema JR, Roth RA, Ganey PE. Fenofibrate, a peroxisome proliferator-activated receptor-alpha agonist, blocks steatosis and alters the inflammatory response in a mouse model of inflammation-dioxin interaction. Chem Biol Interact 2021; 345:109521. [PMID: 34052195 DOI: 10.1016/j.cbi.2021.109521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 04/07/2021] [Accepted: 05/14/2021] [Indexed: 12/01/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (dioxin; TCDD) is an environmental contaminant that elicits a variety of toxic effects, many of which are mediated through activation of the aryl hydrocarbon receptor (AhR). Interaction between AhR and the peroxisome proliferator-activated receptor-alpha (PPAR-α), which regulates fatty acid metabolism, has been suggested. Furthermore, with recognition of the prevalence of inflammatory conditions, there is current interest in the potential for inflammatory stress to modulate the response to environmental agents. The aim of this work was to assess the interaction of TCDD with hepatic inflammation modulated by fenofibrate, a PPAR-α agonist. Female, C57BL/6 mice were treated orally with vehicle or fenofibrate (250 mg/kg) for 13 days, and then were given vehicle or 30 μg/kg TCDD. Four days later, the animals received an i.p. injection of lipopolysaccharide-galactosamine (LPS-GalN) (0.05x107 EU/kg and 500 mg/kg, respectively) to incite inflammation, or saline as vehicle control. After 4 h, the mice were euthanized, and blood and liver samples were collected for analysis. Livers of animals treated with TCDD with or without LPS-GalN had increased lipid deposition, and this effect was blocked by fenofibrate. In TCDD/LPS-GalN-treated mice, fenofibrate caused an increase in plasma activity of alanine aminotransferase, a marker of hepatocellular injury. TCDD reduced LPS-GalN-induced apoptosis, an effect that was prevented by fenofibrate pretreatment. LPS-GalN induced an increase in the concentration of interleukin-6 in plasma and accumulation of neutrophils in liver. TCDD exposure enhanced the former response and inhibited the latter one. These results suggest that fenofibrate counteracts the changes in lipid metabolism induced by TCDD but increases inflammation and liver injury in this model of inflammation-TCDD interaction.
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Affiliation(s)
- Jesus Olivero-Verbel
- Department of Pharmacology and Toxicology. Michigan State University, East Lansing, MI, USA; Environmental and Computational Chemistry Group, School of Pharmaceutical Sciences, University of Cartagena, Cartagena, 130014, Colombia
| | - Jack R Harkema
- Department of Pathobiology and Diagnostic Investigation, Institute for Integrative Toxicology, Michigan State University, USA
| | - Robert A Roth
- Department of Pharmacology and Toxicology. Michigan State University, East Lansing, MI, USA
| | - Patricia E Ganey
- Department of Pharmacology and Toxicology. Michigan State University, East Lansing, MI, USA.
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Sarparast M, Dattmore D, Alan J, Lee KSS. Cytochrome P450 Metabolism of Polyunsaturated Fatty Acids and Neurodegeneration. Nutrients 2020; 12:E3523. [PMID: 33207662 PMCID: PMC7696575 DOI: 10.3390/nu12113523] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/08/2020] [Accepted: 11/10/2020] [Indexed: 12/11/2022] Open
Abstract
Due to the aging population in the world, neurodegenerative diseases have become a serious public health issue that greatly impacts patients' quality of life and adds a huge economic burden. Even after decades of research, there is no effective curative treatment for neurodegenerative diseases. Polyunsaturated fatty acids (PUFAs) have become an emerging dietary medical intervention for health maintenance and treatment of diseases, including neurodegenerative diseases. Recent research demonstrated that the oxidized metabolites, particularly the cytochrome P450 (CYP) metabolites, of PUFAs are beneficial to several neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease; however, their mechanism(s) remains unclear. The endogenous levels of CYP metabolites are greatly affected by our diet, endogenous synthesis, and the downstream metabolism. While the activity of omega-3 (ω-3) CYP PUFA metabolites and omega-6 (ω-6) CYP PUFA metabolites largely overlap, the ω-3 CYP PUFA metabolites are more active in general. In this review, we will briefly summarize recent findings regarding the biosynthesis and metabolism of CYP PUFA metabolites. We will also discuss the potential mechanism(s) of CYP PUFA metabolites in neurodegeneration, which will ultimately improve our understanding of how PUFAs affect neurodegeneration and may identify potential drug targets for neurodegenerative diseases.
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Affiliation(s)
- Morteza Sarparast
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA;
| | - Devon Dattmore
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA;
| | - Jamie Alan
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA;
| | - Kin Sing Stephen Lee
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA;
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA;
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Navarro-Mabarak C, Loaiza-Zuluaga M, Hernández-Ojeda SL, Camacho-Carranza R, Espinosa-Aguirre JJ. Neuroinflammation is able to downregulate cytochrome P450 epoxygenases 2J3 and 2C11 in the rat brain. Brain Res Bull 2020; 163:57-64. [PMID: 32707261 DOI: 10.1016/j.brainresbull.2020.07.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/24/2020] [Accepted: 07/16/2020] [Indexed: 10/23/2022]
Abstract
Cytochrome P450 (CYP) epoxygenases have been considered the main producers of epoxyeicosatrienoic acids (EETs) through the oxidation of arachidonic acid (AA). EETs display various biological properties, notably their powerful anti-inflammatory activities. In the brain, EETs have proven to be neuroprotective and to improve neuroinflammation. However, it is known that inflammation could modify CYP expression. We have previously reported that an inflammatory process in astrocytes is able to down-regulate CYP2J3 and CYP2C11 mRNA, protein levels, and activity (Navarro-Mabarak et al., 2019). In this work, we evaluated the effect of neuroinflammation in protein expression of CYP epoxygenases in the brain. Neuroinflammation was induced by the intraperitoneal administration of LPS (1 mg/kg) to male Wistar rats and was corroborated by IL-6, GFAP, and Iba-1 protein levels in the cortex over time. CYP2J3 and CYP2C11 protein levels were also evaluated in the cortex after 6, 12, 24, 48, and 72 h of LPS treatment. Our results show for the first time that neuroinflammation is able to downregulate CYP2J3 and CYP2C11 protein expression in the brain cortex.
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Affiliation(s)
- C Navarro-Mabarak
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - M Loaiza-Zuluaga
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - S L Hernández-Ojeda
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - R Camacho-Carranza
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - J J Espinosa-Aguirre
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México.
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Navarro-Mabarak C, Mitre-Aguilar IB, Camacho-Carranza R, Arias C, Zentella-Dehesa A, Espinosa-Aguirre JJ. Role of NF-κB in cytochrome P450 epoxygenases down-regulation during an inflammatory process in astrocytes. Neurochem Int 2019; 129:104499. [PMID: 31271766 DOI: 10.1016/j.neuint.2019.104499] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 06/09/2019] [Accepted: 07/01/2019] [Indexed: 12/26/2022]
Abstract
Cytochrome P450 (CYP) epoxygenases and their metabolic products, epoxyeicosatrienoic acids (EETs), have been proposed as important therapeutic targets in the brain. However, CYP expression can be modified by the presence of diverse pro-inflammatory cytokines and the subsequent activation of the NF-κB pathway. It has been indicated that CYP epoxygenases are down-regulated by inflammation in the heart, kidney and liver. However, up to this point, there has been no evidence regarding regulation of CYP epoxygenases during inflammation in the brain. Therefore, in order to explore the effects of inflammation and NF-κB activation in CYP2J3 and CYP2C11 regulation, rat primary astrocytes cultures were treated with LPS with and without IMD-0354 (selective NF-κB inhibitor). Cyp2j3 and Cyp2c11 mRNA expression was determined by qRT-PCR; protein expression was determined by immunofluorescence and by Western Blot and total epoxygenase activity was determined by the quantification of EETs by ELISA. NF-κB binding sites in Cyp2j3 and Cyp2c11 promoter regions were bioinformatically predicted and Electrophoretic Mobility Shift Assays (EMSA) were performed to determine if each hypothetic response element was able to bind NF-κB complexes. Results shown that LPS treatment is able to down-regulate astrocyte CYP2J3 and CYP2C11 mRNA, protein and activity. Additionally, we have identified NK-κB as the transcription factor involved in this regulation.
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Affiliation(s)
- Cynthia Navarro-Mabarak
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Irma Beatriz Mitre-Aguilar
- Unidad de Bioquímica, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ), Av. Vasco de Quiroga Nº 15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, CP.14080, Ciudad de México, Mexico
| | - Rafael Camacho-Carranza
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico; Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Clorinda Arias
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Alejandro Zentella-Dehesa
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico; Unidad de Bioquímica, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ), Av. Vasco de Quiroga Nº 15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, CP.14080, Ciudad de México, Mexico
| | - Jesús Javier Espinosa-Aguirre
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
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Song Y, Nahrgang J, Tollefsen KE. Transcriptomic analysis reveals dose-dependent modes of action of benzo(a)pyrene in polar cod (Boreogadus saida). THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 653:176-189. [PMID: 30408666 DOI: 10.1016/j.scitotenv.2018.10.261] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 10/15/2018] [Accepted: 10/19/2018] [Indexed: 06/08/2023]
Abstract
Polar cod (Boreogadus saida) has been used as a model Arctic species for hazard assessment of environmental stressors such as polycyclic aromatic hydrocarbons (PAHs). However, most of the PAH studies using polar cod rely on targeted biomarker-based analysis thus may not adequately address the complexity of the toxic mechanisms of the stressors. The present study was performed to develop a broad-content transcriptomic platform for polar cod and apply it for understanding the toxic mechanisms of a model PAH, benzo(a)pyrene (BaP). Hepatic transcriptional analysis using a combination of high-density polar cod oligonucleotide microarray and quantitative real-time RT-PCR was conducted to characterize the stress responses in polar cod after 14d repeated dietary exposure to 0.4 (Low) and 20.3 μg/g fish/feeding (High) BaP doses. Bile metabolic analysis was performed to identify the storage of a key BaP hepatic biotransformation product, 3-hydroxybenzo(a)pyrene (3-OH-BaP). The results clearly showed that 3-OH-BaP was detected in the bile of polar cod after both Low and High BaP exposure. Dose-dependent hepatic stress responses were identified, with Low BaP suppressing genes involved in the defense mechanisms and High BaP inducing genes associated with these pathways. The results suggested that activation of the aryl hydrocarbon receptor signaling, induction of oxidative stress, DNA damage and apoptosis were the common modes of action (MoA) of BaP between polar cod or other vertebrates, whereas induction of protein degradation and disturbance of mitochondrial functions were proposed as novel MoAs. Furthermore, conceptual toxicity pathways were proposed for BaP-mediated effects in Arctic fish. The present study has for the first time reported a transcriptome-wide analysis using a polar cod-specific microarray and suggested novel MoAs of BaP. The analytical tools, bioinformatics solutions and mechanistic knowledge generated by this study may facilitate mechanistically-based hazard assessment of environmental stressors in the Arctic using this important fish as a model species.
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Affiliation(s)
- You Song
- Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen 21, N-0349 Oslo, Norway.
| | - Jasmine Nahrgang
- UiT The Arctic University of Norway, Faculty of Biosciences, Fisheries and Economics, Dept. of Arctic and Marine Biology, N-9037 Tromsø, Norway
| | - Knut Erik Tollefsen
- Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen 21, N-0349 Oslo, Norway; Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management, Dept. for Environmental Sciences, Post box 5003, N-1432 Ås, Norway.
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Tang H, Long N, Dai M, Lin L, Li J, Sun F, Guo L. Effect of citral on mouse hepatic cytochrome P450 enzymes. PHARMACEUTICAL BIOLOGY 2018; 56:337-343. [PMID: 29969356 PMCID: PMC6130695 DOI: 10.1080/13880209.2018.1470191] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
CONTEXT Citral is used as a potential natural treatment for various infectious diseases. OBJECTIVE To examine the effect of citral on the mRNA expression and activities of cytochrome P450 (CYP450) enzymes and establish the relationship between citral-induced liver injury and oxidative stress. MATERIALS AND METHODS ICR mice were randomly divided into citral (20, 200, and 2000 mg/kglow), Tween-80, and control groups (0.9% saline), 10 mice in each group. The citral-treated groups were intragastrically administered citral for 3 d, control groups treated with 0.5% Tween-80 and 0.9% saline in the same way. Liver injury and CYP450 enzymes were analyzed by analyzing the histopathological changes and the changes of related enzymes. RESULTS Citral treatment (2000 mg/kg) for 3 d increased serum glutamic pyruvic transaminase and glutamic oxaloacetic transaminase levels, as well as glutathione, gydroxyl radicals, malonaldehyde and total superoxide dismutase contents, but decreased the content of total antioxidant capacity. In doses of 20 and 200 mg/kg groups mice, the contents of NO were decreased significantly and other changes were similar to the 2000 mg/kg group mice, but the liver damage was most severe in the 2000 mg/kg group. Citral induced the mRNA expression and activities of CYP450 1A2, 2D22, and 2E1 in the liver of mice at doses of 20 and 200 mg/kg. There were no changes in testing indexes in Tween-80 treated group mice. Due to its toxic effects, the CYP induction effect of citral negatively correlated with its dose. Although the mRNA expression of CYP450 3A11 was induced by citral, its activity was not affected by low and moderate doses of citral. CYP450 3A11 activity was significantly decreased by high-dose citral. CONCLUSIONS Citral is hepatotoxic and induced oxidative stress in higher dose, which has a negative effect on CYP450 enzymes. These data suggest caution needs to be taken in order to avoid citral-drug interactions in human beings.
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Affiliation(s)
- Huaqiao Tang
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, Sichuan, PR China
- Laboratory of Veterinary Drug Residue Prevention and Control Technology of Animal-derived Food, Chengdu Medical College, Chengdu, Sichuan, PR China
| | - Nana Long
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, Sichuan, PR China
- Laboratory of Veterinary Drug Residue Prevention and Control Technology of Animal-derived Food, Chengdu Medical College, Chengdu, Sichuan, PR China
| | - Min Dai
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, Sichuan, PR China
- Laboratory of Veterinary Drug Residue Prevention and Control Technology of Animal-derived Food, Chengdu Medical College, Chengdu, Sichuan, PR China
- CONTACT Min Dai School of Laboratory Medicine, Chengdu Medical College, Chengdu, Sichuan, PR China
| | - Lin Lin
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, Sichuan, PR China
- Laboratory of Veterinary Drug Residue Prevention and Control Technology of Animal-derived Food, Chengdu Medical College, Chengdu, Sichuan, PR China
| | - Jianlong Li
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, Sichuan, PR China
- Laboratory of Veterinary Drug Residue Prevention and Control Technology of Animal-derived Food, Chengdu Medical College, Chengdu, Sichuan, PR China
| | - Fenghui Sun
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, Sichuan, PR China
- Laboratory of Veterinary Drug Residue Prevention and Control Technology of Animal-derived Food, Chengdu Medical College, Chengdu, Sichuan, PR China
| | - Lijuan Guo
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, Sichuan, PR China
- Laboratory of Veterinary Drug Residue Prevention and Control Technology of Animal-derived Food, Chengdu Medical College, Chengdu, Sichuan, PR China
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9
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Expression of cytochrome P450 epoxygenases and soluble epoxide hydrolase is regulated by hypolipidemic drugs in dose-dependent manner. Toxicol Appl Pharmacol 2018; 355:156-163. [DOI: 10.1016/j.taap.2018.06.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/25/2018] [Accepted: 06/26/2018] [Indexed: 01/30/2023]
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10
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Duszka K, Wahli W. Enteric Microbiota⁻Gut⁻Brain Axis from the Perspective of Nuclear Receptors. Int J Mol Sci 2018; 19:ijms19082210. [PMID: 30060580 PMCID: PMC6121494 DOI: 10.3390/ijms19082210] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/18/2018] [Accepted: 07/23/2018] [Indexed: 12/12/2022] Open
Abstract
Nuclear receptors (NRs) play a key role in regulating virtually all body functions, thus maintaining a healthy operating body with all its complex systems. Recently, gut microbiota emerged as major factor contributing to the health of the whole organism. Enteric bacteria have multiple ways to influence their host and several of them involve communication with the brain. Mounting evidence of cooperation between gut flora and NRs is already available. However, the full potential of the microbiota interconnection with NRs remains to be uncovered. Herewith, we present the current state of knowledge on the multifaceted roles of NRs in the enteric microbiota–gut–brain axis.
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Affiliation(s)
- Kalina Duszka
- Department of Nutritional Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
| | - Walter Wahli
- Lee Kong Chian School of Medicine, Nanyang Technological, 11 Mandalay Road, Singapore 308232, Singapore.
- Center for Integrative Genomics, University of Lausanne, Génopode, CH-1015 Lausanne, Switzerland.
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11
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Wu X, Yang J, Morisseau C, Robertson LW, Hammock B, Lehmler HJ. 3,3',4,4',5-Pentachlorobiphenyl (PCB 126) Decreases Hepatic and Systemic Ratios of Epoxide to Diol Metabolites of Unsaturated Fatty Acids in Male Rats. Toxicol Sci 2016; 152:309-22. [PMID: 27208083 PMCID: PMC4960907 DOI: 10.1093/toxsci/kfw084] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Disruption of the homeostasis of oxygenated regulatory lipid mediators (oxylipins), potential markers of exposure to aryl hydrocarbon receptor (AhR) agonists, such as 3,3',4,4',5-pentachlorobiphenyl (PCB 126), is associated with a range of diseases, including nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Here we test the hypothesis that PCB 126 exposure alters the levels of oxylipins in rats. Male Sprague-Dawley rats (5-weeks old) were treated over a 3-month period every 2 weeks with intraperitoneal injections of PCB 126 in corn oil (cumulative doses of 0, 19.8, 97.8, and 390 µg/kg b.w.; 6 injections total). PCB 126 treatment caused a reduction in growth rates at the highest dose investigated, a dose-dependent decrease in thymus weights, and a dose-dependent increase in liver weights. Liver PCB 126 levels increased in a dose-dependent manner, while levels in plasma were below or close to the detection limit. The ratios of several epoxides to diol metabolites formed via the cytochrome P450 (P450) monooxygenase/soluble epoxide hydrolase (sEH) pathway from polyunsaturated fatty acids displayed a dose-dependent decrease in the liver and plasma, whereas levels of oxylipins formed by other metabolic pathways were generally not altered by PCB 126 treatment. The effects of PCB 126 on epoxide-to-diol ratios were associated with an increased CYP1A activity in liver microsomes and an increased sEH activity in liver cytosol and peroxisomes. These results suggest that oxylipins are potential biomarkers of exposure to PCB 126 and that the P450/sEH pathway is a therapeutic target for PCB 126-mediated hepatotoxicity that warrants further attention.
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Affiliation(s)
- Xianai Wu
- *Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa
| | - Jun Yang
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, California
| | - Christophe Morisseau
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, California
| | - Larry W Robertson
- *Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa
| | - Bruce Hammock
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, California
| | - Hans-Joachim Lehmler
- *Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa
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12
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Nishiyama Y, Nakayama SMM, Watanabe KP, Kawai YK, Ohno M, Ikenaka Y, Ishizuka M. Strain differences in cytochrome P450 mRNA and protein expression, and enzymatic activity among Sprague Dawley, Wistar, Brown Norway and Dark Agouti rats. J Vet Med Sci 2016; 78:675-80. [PMID: 26806536 PMCID: PMC4873860 DOI: 10.1292/jvms.15-0299] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Rat cytochrome P450 (CYP) exhibits inter-strain differences, but their analysis has been
scattered across studies under different conditions. To identify these strain differences
in CYP more comprehensively, mRNA expression, protein expression and metabolic activity
among Wistar (WI), Sprague Dawley (SD), Dark Agouti (DA) and Brown Norway (BN) rats were
compared. The mRNA level and enzymatic activity of CYP1A1 were highest in SD rats. The
rank order of Cyp3a2 mRNA expression mirrored its protein expression,
i.e., DA>BN>SD>WI, and was similar to the CYP3A2-dependent warfarin metabolic
activity, i.e., DA>SD>BN>WI. These results suggest that the strain differences in
CYP3A2 enzymatic activity are caused by differences in mRNA expression.
Cyp2b1 mRNA levels, which were higher in DA rats, did not correlate
with its protein expression or enzymatic activity. This suggests that the strain
differences in enzymatic activity are not related to Cyp2b1 mRNA
expression. In conclusion, WI rats tended to have the lowest CYP1A1, 2B1 and 3A2 mRNA
expression, protein expression and enzymatic activity among the strains. In addition, SD
rats had the highest CYP1A1 mRNA expression and activity, while DA rats had higher CYP2B1
and CYP3A2 mRNA and protein expression. These inter-strain differences in CYP could
influence pharmacokinetic considerations in preclinical toxicological studies.
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Affiliation(s)
- Yoshihiro Nishiyama
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, 18 W9, Kita-ku, Sapporo 060-0818, Japan
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13
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Shmarakov IO. Retinoid-xenobiotic interactions: the Ying and the Yang. Hepatobiliary Surg Nutr 2015; 4:243-67. [PMID: 26311625 DOI: 10.3978/j.issn.2304-3881.2015.05.05] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 05/13/2015] [Indexed: 12/20/2022]
Abstract
The literature provides compelling evidence pointing to tight metabolic interactions between retinoids and xenobiotics. These are extensive and important for understanding xenobiotic actions in the body. Within the body, retinoids affect xenobiotic metabolism and actions and conversely, xenobiotics affect retinoid metabolism and actions. This article summarizes data that establish the importance of retinoid-dependent metabolic pathways for sustaining the body's responses to xenobiotic exposure, including the roles of all-trans- and 9-cis-retinoic acid for protecting mammals from harmful xenobiotic effects and for ensuring xenobiotic elimination from the body. This review will also consider molecular mechanisms underlying xenobiotic toxicity focusing on how this may contribute to retinoid deficiency and disruption of normal retinoid homeostasis. Special attention is paid to xenobiotic molecular targets (nuclear receptors, regulatory proteins, enzymes, and transporters) which affect retinoid metabolism and signaling.
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Affiliation(s)
- Igor O Shmarakov
- Department of Biochemistry and Biotechnology, Chernivtsi National University, Chernivtsi, Ukraine
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14
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Rasmussen MK, Zamaratskaia G. Regulation of porcine hepatic cytochrome p450 - implication for boar taint. Comput Struct Biotechnol J 2014; 11:106-12. [PMID: 25408844 PMCID: PMC4232568 DOI: 10.1016/j.csbj.2014.09.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/29/2014] [Accepted: 09/03/2014] [Indexed: 11/17/2022] Open
Abstract
Cytochrome P450 (CYP450) is the major family of enzymes involved in the metabolism of several xenobiotic and endogenous compounds. Among substrates for CYP450 is the tryptophan metabolite skatole (3-methylindole), one of the major contributors to the off-odour associated with boar-tainted meat. The accumulation of skatole in pigs is highly dependent on the hepatic clearance by CYP450s. In recent years, the porcine CYP450 has attracted attention both in relation to meat quality and as a potential model for human CYP450. The molecular regulation of CYP450 mRNA expression is controlled by several nuclear receptors and transcription factors that are targets for numerous endogenously and exogenously produced agonists and antagonists. Moreover, CYP450 expression and activity are affected by factors such as age, gender and feeding. The regulation of porcine CYP450 has been suggested to have more similarities with human CYP450 than other animal models, including rodents. This article reviews the available data on porcine hepatic CYP450s and its implications for boar taint.
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Affiliation(s)
- Martin Krøyer Rasmussen
- Department of Food Science, Aarhus University, Denmark
- INSERM U1040, University of Montpellier, France
- Corresponding author at: Department of Food Science, Aarhus University, P.O. Box 50, DK-8830 Tjele, Denmark. Tel.: + 45 87 15 74 26.
| | - Galia Zamaratskaia
- Department of Food Science, Swedish University of Agricultural Science, Uppsala, Sweden
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15
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Ibrahim ZS, Ahmed MM, El-Shazly SA, Ishizuka M, Fujita S. Clofibric acid induces hepatic CYP 2B1/2 via constitutive androstane receptor not via peroxisome proliferator activated receptor alpha in rat. Biosci Biotechnol Biochem 2014; 78:1550-9. [PMID: 25052003 DOI: 10.1080/09168451.2014.923302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Peroxisome proliferator activated receptor α (PPARα) ligands, fibrates used to control hyperlipidemia. We demonstrated CYP2B induction by clofibric acid (CFA) however, the mechanism was not clear. In this study, HepG2 cells transfected with expression plasmid of mouse constitutive androstane receptor (CAR) or PPARα were treated with CFA, phenobarbital (PB) or TCPOBOP. Luciferase assays showed that CFA increased CYP2B1 transcription to the same level as PB, or TCPOBOP in HepG2 transfected with mouse CAR But failed to induce it in PPARα transfected cells. CYP2B expressions were increased with PB or CFA in Wistar female rats (having normal levels of CAR) but not in Wistar Kyoto female rats (having low levels of CAR). The induction of CYP2B by PB or CFA was comparable to nuclear CAR levels. CAR nuclear translocation was induced by CFA in both rat strains. This indicates that fibrates can activate CAR and that fibrates-insulin sensitization effect may occur through CAR, while hypolipidemic effect may operate through PPARα.
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Affiliation(s)
- Zein Shaban Ibrahim
- a Faculty of Veterinary Medicine, Department of Physiology , Kafrelsheikh University , Kafrelsheikh , Egypt
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16
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Long M, Ghisari M, Bonefeld-Jørgensen EC. Effects of perfluoroalkyl acids on the function of the thyroid hormone and the aryl hydrocarbon receptor. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:8045-56. [PMID: 23539207 DOI: 10.1007/s11356-013-1628-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 03/11/2013] [Indexed: 05/03/2023]
Abstract
Perfluoroalkyl acids (PFAAs) are perfluorinated compounds that widely exist in the environment and can elicit adverse effects including endocrine disruption in humans and animals. This study investigated the effect of seven PFAAs on the thyroid hormone (TH) system assessing the proliferation of the 3,3',5-triiodo-L-thryonine (T3)-dependent rat pituitary GH3 cells using the T-screen assay and the effect on the aryl hydrocarbon receptor (AhR) transactivation in the AhR-luciferase reporter gene bioassay. A dose-dependent impact on GH3 cells was observed in the range 1×10(-9)-1×10(-4) M: seven PFAAs (perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA)) inhibited the GH3 cell growth, and four PFAAs (PFOS, PFHxS, PFNA, and PFUnA) antagonized the T3-induced GH3 cell proliferation. At the highest test concentration, PFHxS showed a further increase of the T3-induced GH3 growth. Among the seven tested PFAAs, only PFDoA and PFDA elicited an activating effect on the AhR. In conclusion, PFAAs possess in vitro endocrine-disrupting potential by interfering with TH and AhR functions, which need to be taken into consideration when assessing the impact on human health.
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Affiliation(s)
- Manhai Long
- Centre for Arctic Health and Unit of Cellular and Molecular Toxicology, Department of Public Health, Aarhus University, Bartholins Alle 2, Building 1260, 8000, Aarhus C, Denmark,
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17
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Peroxisome proliferator-activated receptors in regulation of cytochromes P450: new way to overcome multidrug resistance? J Biomed Biotechnol 2012; 2012:656428. [PMID: 23193364 PMCID: PMC3492927 DOI: 10.1155/2012/656428] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/16/2012] [Accepted: 09/17/2012] [Indexed: 01/19/2023] Open
Abstract
Embryonic and tumour cells are able to protect themselves against various harmful compounds. In human pathology, this phenomenon exists in the form of multidrug resistance (MDR) that significantly deteriorates success of anticancer treatment. Cytochromes P450 (CYPs) play one of the key roles in the xenobiotic metabolism. CYP expression could contribute to resistance of cancer cells to chemotherapy. CYP epoxygenases (CYP2C and CYP2J) metabolize about 20% of clinically important drugs. Besides of drug metabolism, CYP epoxygenases and their metabolites play important role in embryos, normal body function, and tumors. They participate in angiogenesis, mitogenesis, and cell signaling. It was found that CYP epoxygenases are affected by peroxisome proliferator-activated receptor α (PPARα). Based on the results of current studies, we assume that PPARs ligands may regulate CYP2C and CYP2J and in some extent they may contribute to overcoming of MDR in patients with different types of tumours.
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18
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Corcoran J, Lange A, Winter MJ, Tyler CR. Effects of pharmaceuticals on the expression of genes involved in detoxification in a carp primary hepatocyte model. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:6306-6314. [PMID: 22559005 DOI: 10.1021/es3005305] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Fish in many surface freshwaters are exposed to a range of pharmaceuticals via wastewater treatment works effluent discharges. In mammals the pregnane X receptor (PXR) plays a key role in the regulation of a suite of genes involved in drug biotransformation, but information on the role of this response pathway in fish is limited. Here we investigated the effects of exposure of carp (Cyprinus carpio) primary hepatocytes to the human PXR agonist rifampicin (RIF) on expression of target genes involved in phase I (cyp2k, cyp3a) and phase II (gstα, gstπ) drug metabolism and drug transporters mdr1 and mrp2. RIF induced expression of all target genes measured and the PXR antagonist ketoconazole (KET) inhibited responses of cyp2k and cyp3a. Exposure of the primary carp hepatocytes to the pharmaceuticals ibuprofen (IBU), clotrimazole (CTZ), clofibric acid (CFA) and propranolol (PRP), found responses to IBU and CFA, but not CTZ or PRP. This is in contrast with mammals, where CTZ is a potent PXR-agonist. Collectively our data indicate potential PXR involvement in regulating selected genes involved in drug metabolism in fish, but suggest some divergence in the regulation pathways with those in mammals. The carp primary hepatocyte model serves as a useful system for screening for responses in these target genes involved in drug metabolism.
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Affiliation(s)
- Jenna Corcoran
- University of Exeter, Biosciences, College of Life & Environmental Sciences, Exeter, United Kingdom
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19
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Večeřa R, Zachařová A, Orolin J, Strojil J, Skottová N, Anzenbacher P. Fenofibrate-induced decrease of expression of CYP2C11 and CYP2C6 in rat. Biopharm Drug Dispos 2011; 32:482-7. [PMID: 21968795 DOI: 10.1002/bdd.774] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 06/17/2011] [Accepted: 08/15/2011] [Indexed: 11/10/2022]
Abstract
This short communication is aimed to investigate whether the widely used hypolipidemic drug fenofibrate affects CYP2C11 and CYP2C6 in rats, both counterparts of human CYP2C9, known to metabolise many drugs including S-warfarin and largely used non-steroidal antiinflammatory drugs such as ibuprofen, diclofenac and others. The effects of fenofibrate on the expression of rat liver CYP2C11 and CYP2C6 were studied in both healthy Wistar rats and hereditary hypertriglyceridemic rats. Both strains of rats were fed on diet containing fenofibrate (0.1% w/w) for 20 days. Fenofibrate highly significantly suppressed the expression of mRNA of CYP2C11 and less that of CYP2C6 in liver microsomes of both rat strains; this effect was associated with a corresponding decrease in protein levels. The results indicate that the combination of fenofibrate with drugs metabolised by CYP2C9 in humans should be taken with caution as it may lead, for example, to the potentiation of warfarin effects. This type of drug interaction has been observed previously and the results presented here could contribute to the explanation of their mechanism.
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Affiliation(s)
- Rostislav Večeřa
- Institute of Pharmacology, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská, 3, 775 15 Olomouc, Czech Republic
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20
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Gentry PR, Clewell HJ, Clewell R, Campbell J, Van Landingham C, Shipp AM. Challenges in the application of quantitative approaches in risk assessment: a case study with di-(2-ethylhexyl)phthalate. Crit Rev Toxicol 2011; 41 Suppl 2:1-72. [DOI: 10.3109/10408444.2011.599366] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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21
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Anwar-Mohamed A, Degenhardt OS, El Gendy MA, Seubert JM, Kleeberger SR, El-Kadi AO. The effect of Nrf2 knockout on the constitutive expression of drug metabolizing enzymes and transporters in C57Bl/6 mice livers. Toxicol In Vitro 2011; 25:785-95. [DOI: 10.1016/j.tiv.2011.01.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 01/13/2011] [Accepted: 01/24/2011] [Indexed: 01/06/2023]
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22
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Jain RB, Wang RY. Association of caffeine consumption and smoking status with the serum concentrations of polychlorinated biphenyls, dioxins, and furans in the general U.S. population: NHANES 2003-2004. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2011; 74:1225-39. [PMID: 21797774 DOI: 10.1080/15287394.2011.587105] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Smoking appears to enhance the body's clearance of dioxins and dioxin-like polychlorinated biphenyls (PCB) by inducing CYP1A2 activity based on studies with a limited number of participants. This hypothesis was evaluated by using data from National Health and Nutrition Examination Survey. Specifically, adult participants were identified and the sums of their serum lipid-adjusted concentrations of 12 polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/PCDF) congeners, 33 PCB (total), 26 non-dioxin-like PCB, and 6 mono-ortho (dioxin-like) PCB were determined. In addition to evaluating the association of smoking, the association of caffeine consumption and the interaction between them was evaluated. Data analysis included regression models that were fitted with age, gender, race/ethnicity, and body mass index (BMI). R(2) varied from 34.8 to 66%. Smokers had significantly lower concentrations of total PCDD/PCDF than nonsmokers. New to this study, a siginificant interaction between caffeine consumption and smoking for total PCB was found. When caffeine was consumed less than once a day, smokers had higher concentrations of total PCB than nonsmokers. However, when caffeine was consumed at least once a day, smokers had lower concentrations than nonsmokers. A significant interaction between age and caffeine consumption frequency for each of the PCB groups was also observed. The differences in concentration between younger and older age groups were greater when caffeine was consumed at least once a day than when caffeine was consumed less frequently. Smoking and caffeine consumption need to be considered in the interpretation of human biomonitoring data because they appear to affect the serum concentrations of these chemicals.
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Affiliation(s)
- Ram B Jain
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA
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23
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Rodricks JV, Swenberg JA, Borzelleca JF, Maronpot RR, Shipp AM. Triclosan: a critical review of the experimental data and development of margins of safety for consumer products. Crit Rev Toxicol 2010; 40:422-84. [PMID: 20377306 DOI: 10.3109/10408441003667514] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Triclosan (2,4,4'-trichloro-2'-hydroxy-diphenyl ether) is an antibacterial compound that has been used in consumer products for about 40 years. The tolerability and safety of triclosan has been evaluated in human volunteers with little indication of toxicity or sensitization. Although information in humans from chronic usage of personal care products is not available, triclosan has been extensively studied in laboratory animals. When evaluated in chronic oncogenicity studies in mice, rats, and hamsters, treatment-related tumors were found only in the liver of male and female mice. Application of the Human Relevance Framework suggested that these tumors arose by way of peroxisome proliferator-activated receptor alpha (PPARalpha) activation, a mode of action not considered to be relevant to humans. Consequently, a Benchmark Dose (BMDL(10)) of 47 mg/kg/day was developed based on kidney toxicity in the hamster. Estimates of the amount of intake from in the use of representative personal care products for men, women, and children were derived in two ways: (1) using known or assumed triclosan levels in various consumer products and assumed usage patterns (product-based estimates); and (2) using upper bound measured urinary triclosan levels from human volunteers (biomonitoring-based estimates) using data from the Centers for Disease Control and Prevention. For the product-based estimates, the margin of safety (MOS) for the combined exposure estimates of intake from the use of all triclosan-containing products considered were approximately 1000, 730, and 630 for men, women, and children, respectively. The MOS calculated from the biomonitoring-based estimated intakes were 5200, 6700, and 11,750 for men, women, and children, respectively. Based on these results, exposure to triclosan in consumer products is not expected to cause adverse health effects in children or adults who use these products as intended.
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Traber MG, Mustacich DJ, Sullivan LC, Leonard SW, Ahern-Rindell A, Kerkvliet N. Vitamin E status and metabolism in adult and aged aryl hydrocarbon receptor null mice. J Nutr Biochem 2010; 21:1193-9. [PMID: 20153623 DOI: 10.1016/j.jnutbio.2009.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 10/05/2009] [Accepted: 10/19/2009] [Indexed: 12/28/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is involved in regulation of mechanisms for detoxification of xenobiotics, as well as vitamin A metabolism. Vitamin E is a fat-soluble nutrient whose metabolism is initialized via the cytochrome P450 system. Thus, AhR absence could alter hepatic regulation of α-tocopherol metabolism. To test this hypothesis, we assessed vitamin E status in adult (2-5 m) and old (21-22 m), wild-type and AhR-null mice. Plasma α-tocopherol concentrations in AhR-null mice (2.3±1.2 μmol/L, n=19) were lower than those of wild-type mice (3.2±1.2, n=17, P=.0131); those in old mice (3.2±1.2, n=20) were higher than those of adults (2.2±1.0, n=16, P=.0075). Hepatic α-tocopherol concentrations were not different between genotypes, but were nearly double in old (32±8 nmol/g, n=20) as compared with adult mice (17±2, n=16, P<.0001). Hepatic Cyp3a concentrations in AhR-null mice were greater than those in wild-type mice (P=.0011). Genotype (P=.0047), sex (P<.0001) and age (P<.0001) were significant modifiers of liver α-tocopherol metabolite (α-CEHC) concentrations. In general, Cyp3a concentrations correlated with hepatic α-tocopherol (r=0.3957, P<.05) and α-CEHC (r=0.4260, P<.05) concentrations. Since there were no significant genotype differences in the hepatic α- or γ-tocopherol concentrations, AhR-null mice did not have dramatically altered vitamin E metabolism. Since they did have higher hepatic α-CEHC concentrations, these data suggest metabolism was up-regulated in the AhR-null mice in order to maintain the hepatic tocopherol concentrations similar to those of wild-type mice.
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Affiliation(s)
- Maret G Traber
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA.
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Watanabe MX, Jones SP, Iwata H, Kim EY, Kennedy SW. Effects of co-exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin and perfluorooctane sulfonate or perfluorooctanoic acid on expression of cytochrome P450 isoforms in chicken (Gallus gallus) embryo hepatocyte cultures. Comp Biochem Physiol C Toxicol Pharmacol 2009; 149:605-12. [PMID: 19167519 DOI: 10.1016/j.cbpc.2009.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 12/23/2008] [Accepted: 01/06/2009] [Indexed: 11/18/2022]
Abstract
In this study we investigated the effect of a single-compound exposure or two compound co-exposure to tetrachlorodibenzo-p-dioxin (TCDD) plus perfluorooctane sulfonate (PFOS) or perfluorooctanoic acid (PFOA) on the mRNA expression of cytochromes P450 (CYP) 1A4, 4V2 and 3A37, ethoxyresorufin-O-deethylase (EROD) activity and cell viability in chicken (Gallus gallus domesticus) embryo primary hepatocyte cultures. Cell viability after 24 h of incubation was significantly decreased in cells exposed to PFOS at concentrations between 30 microM and 60 microM with or without co-exposure to TCDD (0.3 nM at maximum). PFOA did not decrease cell viability even at maximum concentrations of 60 microM. TCDD induced CYP1A4 mRNA and EROD activity substantially as reported previously. PFOS also increased CYP1A4 mRNA in a concentration-dependent manner. Co-exposure of cells to PFOS plus TCDD did not change CYP1A4 mRNA levels compared to cells treated with TCDD alone. PFOS alone did not induce CYP4V2 mRNA, however 40-50 microM PFOS plus TCDD (0.3 nM) induced CYP4V2 mRNA compared to TCDD alone (P<0.05). This trend was similar to that observed with co-exposure to TCDD plus PFOA, suggesting that PFOA alone did not induce CYP4V2 mRNA, whereas co-exposure to TCDD plus PFOA induced the expression levels. PFOS alone decreased CYP3A37 mRNA by a maximum of 45%, however after co-exposure to TCDD, recovery of mRNA expression to levels measured in DMSO-treated cells was observed. Our data suggest a complex gene response to mixtures of dioxin-like and perfluorinated compounds.
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Affiliation(s)
- Michio X Watanabe
- National Wildlife Research Centre, Environment Canada, Carleton University, Ottawa, ON, Canada
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Golden R, Kimbrough R. Weight of Evidence Evaluation of Potential Human Cancer Risks from Exposure to Polychlorinated Biphenyls: An Update Based on Studies Published Since 2003. Crit Rev Toxicol 2009; 39:299-331. [DOI: 10.1080/10408440802291521] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Sawaya RM, Riddick DS. Cytochrome P450 2C11 5'-flanking region and promoter mediate in vivo suppression by 3-methylcholanthrene. Drug Metab Dispos 2008; 36:1803-11. [PMID: 18524872 DOI: 10.1124/dmd.108.020966] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Aromatic hydrocarbons such as 3-methylcholanthrene (MC) elicit toxic and adaptive responses through the aryl hydrocarbon receptor (AHR). Aromatic hydrocarbons act via an unknown mechanism to suppress the transcription of CYP2C11, a growth hormone-regulated gene encoding the male-specific rat hepatic cytochrome P450 2C11. We hypothesize that suppression of CYP2C11 by aromatic hydrocarbons is mediated by the gene's promoter and 5'-flank. Using hydrodynamics-based injections to deliver plasmid DNA to the liver of live rats, we studied the MC responsiveness of luciferase constructs containing 10.1, 5.6, and 2.4 kilobases (kb) of the CYP2C11 5'-flank. MC suppressed CYP2C11-luciferase activity of the 10.1- and 5.6-kb constructs to less than 50% of vehicle levels by 24 and 72 h. Luciferase activity of the 2.4-kb CYP2C11 construct was decreased to 63% of vehicle levels 24 h after MC treatment, but no suppression was detected by 72 h. Negative regulatory element(s) responsible for CYP2C11 reporter suppression by MC exist in the proximal 2.4 kb of the 5'-flank; however, additional cis-acting elements located between -5.6 and -2.4 kb mediate persistent reporter suppression. As a positive control for AHR activation, MC dramatically induced the luciferase activity of a Cyp1a1-driven luciferase plasmid under AHR control. Modulation of reporter gene activity by MC was accompanied by induction of endogenous CYP1A1 and suppression of endogenous CYP2C11 mRNA/protein. This is the first demonstration of aromatic hydrocarbon-mediated suppression of a CYP2C11-luciferase construct, and this finding suggests that the 5'-flanking region and promoter mediate down-regulation of this gene in the intact rat.
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Affiliation(s)
- Rana M Sawaya
- Department of Pharmacology and Toxicology, Medical Sciences Building, University of Toronto, Toronto, ON, Canada
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Sawaya RM, Riddick DS. Cytochrome P450 2C11 5'-flanking region and promoter: regulation by aromatic hydrocarbons in vitro. Toxicology 2008; 248:104-12. [PMID: 18440119 DOI: 10.1016/j.tox.2008.03.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Revised: 03/12/2008] [Accepted: 03/15/2008] [Indexed: 12/13/2022]
Abstract
Aromatic hydrocarbons elicit toxic and adaptive responses via the aryl hydrocarbon receptor (AHR). Aromatic hydrocarbons suppress the transcription of the growth hormone-regulated, male-specific rat hepatic cytochrome P450 2C11 gene (CYP2C11) in vivo via an unknown mechanism. We hypothesize that the suppression of CYP2C11 by aromatic hydrocarbons is mediated by the gene's promoter and 5'-flanking region. Following bioinformatic analysis of putative transcription factor (TF) binding sites, we cloned extended lengths of the CYP2C11 5'-flanking region into a promoterless luciferase plasmid. Suppression of CYP2C11 constructs was not observed upon treatment of transfected rat 5L, BP8 or mouse Hepa-1 cells with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 3-methylcholanthrene. In human HepG2 cells, the 10.1-kb construct displayed a pronounced 6- to 8-fold induction by TCDD. Deletion analysis localized the paradoxical induction response to a region between -1.8 kb and -1.3 kb, which contains a dioxin-responsive element (DRE) previously shown by us to be capable of binding activated AHR. This was confirmed by site-directed mutagenesis of the DRE. Induction of the 10.1-kb construct by TCDD in HepG2 cells was blocked by alpha-naphthoflavone, an AHR antagonist/partial agonist. The AHR is likely involved in the induction of CYP2C11-luciferase activity by TCDD in HepG2 cells and this response is at least partly DRE-mediated. Although CYP2C11 is suppressed by aromatic hydrocarbons in vivo, CYP2C11-luciferase constructs display a potentially misleading paradoxical induction in vitro that is cell-specific. Regulation of CYP2C11-luciferase plasmids is being studied in vivo in rat liver, where an intact endocrine system and the full complement of TFs needed for CYP2C11 suppression are present.
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Affiliation(s)
- Rana M Sawaya
- Department of Pharmacology & Toxicology, Medical Sciences Building, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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Richert L, Tuschl G, Viollon-Abadie C, Blanchard N, Bonet A, Heyd B, Halkic N, Wimmer E, Dolgos H, Mueller SO. Species Differences in the Response of Liver Drug-Metabolizing Enzymes to (S)-4-O-Tolylsulfanyl-2-(4-trifluormethyl-phenoxy)-butyric Acid (EMD 392949) in Vivo and in Vitro. Drug Metab Dispos 2008; 36:702-14. [DOI: 10.1124/dmd.107.018358] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Brown JF, Mayes BA, Silkworth JB, Hamilton SB. Polychlorinated biphenyls modulated tumorigenesis in Sprague Dawley rats: correlation with mixed function oxidase activities and superoxide (O2* ) formation potentials and implied mode of action. Toxicol Sci 2007; 98:375-94. [PMID: 17510085 DOI: 10.1093/toxsci/kfm122] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Parallel, chronic (24 months) multidose bioassays of the PCB (polychlorinated biphenyls) Aroclors 1016, 1242, 1254, and 1260 in male and female Sprague-Dawley rats showed sex/Aroclor-dependent increases in hepatic tumors and decreases in extrahepatic tumors. To elucidate the PCB mode of action (MOA) involved, levels of a number of hypothesized mediators were measured in liver specimens collected at 3, 6, 12, 18, and 24 months and screened for correlation with late life hepatotumorigenesis (HT; mostly adenomas). Consistently correlated with HT were (1) tissue accumulations of SigmaPCBs (correlated in both sexes) and of dioxin equivalents (toxic equivalency [TEQ]; correlated in females only); (2) net activities of six groups of mixed function oxidases (MFOs), some PCB-induced, some PCB-repressed, as determined by differential metabolism of PCB congeners; (3) activities of deproteinated, reoxidized hepatic cytosols as catalysts for superoxide (O(2)(*-)) production, such activity having the chemical characteristics of redox-cycling quinones (RCQs), e.g., those derived from the glutathionylated estrogen catechols that were identified in the female rat livers; and (4) increased expression of the indicator of cell proliferation, proliferating cell nuclear antigen. The new findings, along with other recently reported relationships, were indicative of a MOA consisting of (1) SigmaPCB/TEQ accumulation in rat tissues; (2) SigmaPCB/TEQ repression of constitutive MFOs; (3) SigmaPCB/TEQ induction of other MFOs; (4) MFO-mediated formation of RCQs; (5) RCQ-mediated formation of O(2)(*-); (6) O(2)(*-) dismutation to H(2)O(2); and (7) H(2)O(2)-mediated mitotic signaling, resulting in the proliferation of spontaneously or otherwise initiated cells to form hepatic tumors, as in tumor promotion.
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Affiliation(s)
- John F Brown
- General Electric Company, Fairfield, Connecticut 06431, USA.
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Spector AA, Norris AW. Action of epoxyeicosatrienoic acids on cellular function. Am J Physiol Cell Physiol 2006; 292:C996-1012. [PMID: 16987999 DOI: 10.1152/ajpcell.00402.2006] [Citation(s) in RCA: 352] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Epoxyeicosatrienoic acids (EETs), which function primarily as autocrine and paracrine mediators in the cardiovascular and renal systems, are synthesized from arachidonic acid by cytochrome P-450 epoxygenases. They activate smooth muscle large-conductance Ca(2+)-activated K(+) channels, producing hyperpolarization and vasorelaxation. EETs also have anti-inflammatory effects in the vasculature and kidney, stimulate angiogenesis, and have mitogenic effects in the kidney. Many of the functional effects of EETs occur through activation of signal transduction pathways and modulation of gene expression, events probably initiated by binding to a putative cell surface EET receptor. However, EETs are rapidly taken up by cells and are incorporated into and released from phospholipids, suggesting that some functional effects may occur through a direct interaction between the EET and an intracellular effector system. In this regard, EETs and several of their metabolites activate peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma, suggesting that some functional effects may result from PPAR activation. EETs are metabolized primarily by conversion to dihydroxyeicosatrienoic acids (DHETs), a reaction catalyzed by soluble epoxide hydrolase (sEH). Many potentially beneficial actions of EETs are attenuated upon conversion to DHETs, which do not appear to be essential under routine conditions. Therefore, sEH is considered a potential therapeutic target for enhancing the beneficial functions of EETs.
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Affiliation(s)
- Arthur A Spector
- Dept. of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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Rifkind AB. CYP1A in TCDD toxicity and in physiology-with particular reference to CYP dependent arachidonic acid metabolism and other endogenous substrates. Drug Metab Rev 2006; 38:291-335. [PMID: 16684662 DOI: 10.1080/03602530600570107] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Toxicologic and physiologic roles of CYP1A enzyme induction, the major biochemical effect of aryl hydrocarbon receptor activation by TCDD and other receptor ligands, are unknown. Evidence is presented that CYP1A exerts biologic effects via metabolism of endogenous substrates (i.e., arachidonic acid, other eicosanoids, estrogens, bilirubin, and melatonin), production of reactive oxygen, and effects on K(+) and Ca(2+) channels. These interrelated pathways may connect CYP1A induction to TCDD toxicities, including cardiotoxicity, vascular dysfunction, and wasting. They may also underlie homeostatic roles for CYP1A, especially when transiently induced by common chemical exposures and environmental conditions (i.e., tryptophan photoproducts, dietary indoles, and changes in oxygen tension).
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Affiliation(s)
- Arleen B Rifkind
- Department of Pharmacology, Weill Medical College of Cornell University, New York, NY 10021, USA.
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