51
|
Igami K, Shimojo Y, Ito H, Miyazaki T, Kashiwada Y. Hepatoprotective effect of fermented ginseng and its major constituent compound K in a rat model of paracetamol (acetaminophen)-induced liver injury. J Pharm Pharmacol 2014; 67:565-72. [DOI: 10.1111/jphp.12342] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 08/19/2014] [Indexed: 12/26/2022]
Abstract
Abstract
Objectives
This work aimed at evaluating the effect of fermented ginseng (FG) and fermented red ginseng (FRG) against rat liver injury caused by paracetamol (acetaminophen (APAP)).
Methods
Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the serum and histopathological changes in the liver were analysed to determine the degree of liver injury. Deoxyribonucleic acid (DNA) microarray analysis was performed to compare gene expression levels altered in the rat livers. Phosphorylated Jun-N-terminal kinase (JNK) in human hepatocellular carcinoma (HepG2) cells were detected using western blot analysis to investigate the anti-inflammatory activity of compound K.
Key findings
Pretreatment with FG, containing compound K at high concentration, attenuated AST as well as ALT levels in rats, while no obvious effect was observed in the group that received FRG, whose content of compound K was lower than that of FG. In addition, the results of our histopathological analysis were consistent with changes in the serum biochemical analysis. DNA microarray analysis indicated that JNK- and glutathione S-transferase (GST)-related genes were involved in the hepatotoxicity. Notably, compound K, a major ginsenoside in FG, inhibited the phosphorylation of JNK in HepG2 cells.
Conclusions
FG was shown to possess hepatoprotective activity against paracetamol (APAP)-induced liver injury better than FRG. Compound K might play an important role for an anti-inflammatory activity of FG by inhibiting JNK signalling in the liver.
Collapse
Affiliation(s)
- Kentaro Igami
- Research & Development Center, Nagase and CO., LTD, Kobe, Hyogo, Japan
| | - Yosuke Shimojo
- Research & Development Center, Nagase and CO., LTD, Kobe, Hyogo, Japan
| | - Hisatomi Ito
- Research & Development Center, Nagase and CO., LTD, Kobe, Hyogo, Japan
| | | | - Yoshiki Kashiwada
- Graduate School of Pharmaceutical Sciences, University of Tokushima, Shomachi, Tokushima, Japan
| |
Collapse
|
52
|
Jennings P, Schwarz M, Landesmann B, Maggioni S, Goumenou M, Bower D, Leonard MO, Wiseman JS. SEURAT-1 liver gold reference compounds: a mechanism-based review. Arch Toxicol 2014; 88:2099-133. [DOI: 10.1007/s00204-014-1410-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 10/01/2014] [Indexed: 12/20/2022]
|
53
|
Stamper BD. Transcriptional profiling of reactive metabolites for elucidating toxicological mechanisms: a case study of quinoneimine-forming agents. Drug Metab Rev 2014; 47:45-55. [DOI: 10.3109/03602532.2014.978081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
54
|
Tobwala S, Khayyat A, Fan W, Ercal N. Comparative evaluation of N-acetylcysteine and N-acetylcysteineamide in acetaminophen-induced hepatotoxicity in human hepatoma HepaRG cells. Exp Biol Med (Maywood) 2014; 240:261-72. [PMID: 25245075 DOI: 10.1177/1535370214549520] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Acetaminophen (N-acetyl-p-aminophenol, APAP) is one of the most widely used over-the-counter antipyretic analgesic medications. Despite being safe at therapeutic doses, an accidental or intentional overdose can result in severe hepatotoxicity; a leading cause of drug-induced liver failure in the U.S. Depletion of glutathione (GSH) is implicated as an initiating event in APAP-induced toxicity. N-acetylcysteine (NAC), a GSH precursor, is the only currently approved antidote for an APAP overdose. Unfortunately, fairly high doses and longer treatment times are required due to its poor bioavailability. In addition, oral and intravenous administration of NAC in a hospital setting are laborious and costly. Therefore, we studied the protective effects of N-acetylcysteineamide (NACA), a novel antioxidant, with higher bioavailability and compared it with NAC in APAP-induced hepatotoxicity in a human-relevant in vitro system, HepaRG. Our results indicated that exposure of HepaRG cells to APAP resulted in GSH depletion, reactive oxygen species (ROS) formation, increased lipid peroxidation, mitochondrial dysfunction (assessed by JC-1 fluorescence), and lactate dehydrogenase release. Both NAC and NACA protected against APAP-induced hepatotoxicity by restoring GSH levels, scavenging ROS, inhibiting lipid peroxidation, and preserving mitochondrial membrane potential. However, NACA was better than NAC at combating oxidative stress and protecting against APAP-induced damage. The higher efficiency of NACA in protecting cells against APAP-induced toxicity suggests that NACA can be developed into a promising therapeutic option for treatment of an APAP overdose.
Collapse
Affiliation(s)
- Shakila Tobwala
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, USA
| | - Ahdab Khayyat
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, USA
| | - Weili Fan
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, USA
| | - Nuran Ercal
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, USA
| |
Collapse
|
55
|
Vredenburg G, Elias NS, Venkataraman H, Hendriks DFG, Vermeulen NPE, Commandeur JNM, Vos JC. Human NAD(P)H:quinone Oxidoreductase 1 (NQO1)-Mediated Inactivation of Reactive Quinoneimine Metabolites of Diclofenac and Mefenamic Acid. Chem Res Toxicol 2014; 27:576-86. [DOI: 10.1021/tx400431k] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Galvin Vredenburg
- Division
of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Naura S. Elias
- Division
of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Harini Venkataraman
- Division
of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Delilah F. G. Hendriks
- Division
of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Nico P. E. Vermeulen
- Division
of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Jan N. M. Commandeur
- Division
of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - J. Chris Vos
- Division
of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| |
Collapse
|
56
|
Forman HJ, Ursini F, Maiorino M. An overview of mechanisms of redox signaling. J Mol Cell Cardiol 2014; 73:2-9. [PMID: 24512843 DOI: 10.1016/j.yjmcc.2014.01.018] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/24/2014] [Accepted: 01/27/2014] [Indexed: 10/25/2022]
Abstract
A principal characteristic of redox signaling is that it involves an oxidation-reduction reaction or covalent adduct formation between the sensor signaling protein and second messenger. Non-redox signaling may involve alteration of the second messenger as in hydrolysis of GTP by G proteins, modification of the signaling protein as in farnesylation, or simple non-covalent binding of an agonist or second messenger. The chemistry of redox signaling is reviewed here. Specifically we have described how among the so-called reactive oxygen species, only hydroperoxides clearly fit the role of a second messenger. Consideration of reaction kinetics and cellular location strongly suggests that for hydroperoxides, particular protein cysteines are the targets and that the requirements for redox signaling is that these cysteines are in microenvironments in which the cysteine is ionized to the thiolate, and a proton can be donated to form a leaving group. The chemistry described here is the same as occurs in the cysteine and selenocysteine peroxidases that are generally considered the primary defense against oxidative stress. But, these same enzymes can also act as the sensors and transducer for signaling. Conditions that would allow specific signaling by peroxynitrite and superoxide are also defined. Signaling by other electrophiles, which includes lipid peroxidation products, quinones formed from polyphenols and other metabolites also involves reaction with specific protein thiolates. Again, kinetics and location are the primary determinants that provide specificity required for physiological signaling although enzymatic catalysis is not likely involved. This article is part of a Special Issue entitled "Redox Signalling in the Cardiovascular System".
Collapse
Affiliation(s)
- Henry Jay Forman
- Life and Environmental Sciences Unit, University of California, Merced, 5200 N. Lake Road, Merced, CA 95344, USA; Andrus Gerontology Center of the Davis School of Gerontology, University of Southern, California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA.
| | - Fulvio Ursini
- Dipartmento di Medicina Molecolare, Università di Padova, Viale G. Colombo 3, I-35121 Padova, Italy
| | - Matilde Maiorino
- Dipartmento di Medicina Molecolare, Università di Padova, Viale G. Colombo 3, I-35121 Padova, Italy
| |
Collapse
|
57
|
Mohar I, Stamper BD, Rademacher PM, White CC, Nelson SD, Kavanagh TJ. Acetaminophen-induced liver damage in mice is associated with gender-specific adduction of peroxiredoxin-6. Redox Biol 2014; 2:377-87. [PMID: 24563856 PMCID: PMC3926121 DOI: 10.1016/j.redox.2014.01.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Revised: 01/10/2014] [Accepted: 01/10/2014] [Indexed: 11/29/2022] Open
Abstract
The mechanism by which acetaminophen (APAP) causes liver damage evokes many aspects drug metabolism, oxidative chemistry, and genetic-predisposition. In this study, we leverage the relative resistance of female C57BL/6 mice to APAP-induced liver damage (AILD) compared to male C57BL/6 mice in order to identify the cause(s) of sensitivity. Furthermore, we use mice that are either heterozygous (HZ) or null (KO) for glutamate cysteine ligase modifier subunit (Gclm), in order to titrate the toxicity relative to wild-type (WT) mice. Gclm is important for efficient de novo synthesis of glutathione (GSH). APAP (300 mg/kg, ip) or saline was administered and mice were collected at 0, 0.5, 1, 2, 6, 12, and 24 h. Male mice showed marked elevation in serum alanine aminotransferase by 6 h. In contrast, female WT and HZ mice showed minimal toxicity at all time points. Female KO mice, however, showed AILD comparable to male mice. Genotype-matched male and female mice showed comparable APAP-protein adducts, with Gclm KO mice sustaining significantly greater adducts. ATP was depleted in mice showing toxicity, suggesting impaired mitochondria function. Indeed, peroxiredoxin-6, a GSH-dependent peroxiredoxin, was preferentially adducted by APAP in mitochondria of male mice but rarely adducted in female mice. These results support parallel mechanisms of toxicity where APAP adduction of peroxiredoxin-6 and sustained GSH depletion results in the collapse of mitochondria function and hepatocyte death. We conclude that adduction of peroxiredoxin-6 sensitizes male C57BL/6 mice to toxicity by acetaminophen.
Collapse
Affiliation(s)
- Isaac Mohar
- Department of Environmental and Occupational Health Sciences, University of Washington, Box 354695, Seattle, WA 98195, USA
| | - Brendan D Stamper
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Peter M Rademacher
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Collin C White
- Department of Environmental and Occupational Health Sciences, University of Washington, Box 354695, Seattle, WA 98195, USA
| | - Sidney D Nelson
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Terrance J Kavanagh
- Department of Environmental and Occupational Health Sciences, University of Washington, Box 354695, Seattle, WA 98195, USA
| |
Collapse
|
58
|
Dragovic S, Venkataraman H, Begheijn S, Vermeulen NP, Commandeur JN. Effect of human glutathione S-transferase hGSTP1-1 polymorphism on the detoxification of reactive metabolites of clozapine, diclofenac and acetaminophen. Toxicol Lett 2014; 224:272-81. [DOI: 10.1016/j.toxlet.2013.10.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 10/19/2013] [Accepted: 10/23/2013] [Indexed: 01/01/2023]
|
59
|
Forman HJ, Davies KJA, Ursini F. How do nutritional antioxidants really work: nucleophilic tone and para-hormesis versus free radical scavenging in vivo. Free Radic Biol Med 2014; 66:24-35. [PMID: 23747930 PMCID: PMC3852196 DOI: 10.1016/j.freeradbiomed.2013.05.045] [Citation(s) in RCA: 487] [Impact Index Per Article: 48.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 05/29/2013] [Accepted: 05/30/2013] [Indexed: 02/07/2023]
Abstract
We present arguments for an evolution in our understanding of how antioxidants in fruits and vegetables exert their health-protective effects. There is much epidemiological evidence for disease prevention by dietary antioxidants and chemical evidence that such compounds react in one-electron reactions with free radicals in vitro. Nonetheless, kinetic constraints indicate that in vivo scavenging of radicals is ineffective in antioxidant defense. Instead, enzymatic removal of nonradical electrophiles, such as hydroperoxides, in two-electron redox reactions is the major antioxidant mechanism. Furthermore, we propose that a major mechanism of action for nutritional antioxidants is the paradoxical oxidative activation of the Nrf2 (NF-E2-related factor 2) signaling pathway, which maintains protective oxidoreductases and their nucleophilic substrates. This maintenance of "nucleophilic tone," by a mechanism that can be called "para-hormesis," provides a means for regulating physiological nontoxic concentrations of the nonradical oxidant electrophiles that boost antioxidant enzymes, and damage removal and repair systems (for proteins, lipids, and DNA), at the optimal levels consistent with good health.
Collapse
Affiliation(s)
- Henry J Forman
- University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA; Andrus Gerontology Center of the Davis School of Gerontology, University of Southern, California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Kelvin J A Davies
- Andrus Gerontology Center of the Davis School of Gerontology, University of Southern, California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA; Division of Molecular & Computational Biology, Department of Biological Sciences, Dornsife College of Letters, Arts, and Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Fulvio Ursini
- Department of Molecular Medicine, University of Padova, Viale G. Colombo 3, I-35121, Padova, Italy.
| |
Collapse
|
60
|
Dragovic S, Boerma JS, Vermeulen NPE, Commandeur JNM. Effect of Human Glutathione S-Transferases on Glutathione-Dependent Inactivation of Cytochrome P450-Dependent Reactive Intermediates of Diclofenac. Chem Res Toxicol 2013; 26:1632-41. [DOI: 10.1021/tx400204d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Sanja Dragovic
- Division of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Jan Simon Boerma
- Division of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Nico P. E. Vermeulen
- Division of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Jan N. M. Commandeur
- Division of Molecular Toxicology,
Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty
of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| |
Collapse
|
61
|
Navid A, Ng DM, Stewart BJ, Wong SE, Lightstone FC. Quantitative In Silico analysis of transient metabolism of acetaminophen and associated causes of hepatotoxicity in humans. In Silico Pharmacol 2013. [PMCID: PMC4750864 DOI: 10.1186/2193-9616-1-14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
|
62
|
El-Agamy DS, Makled MN, Gamil NM. Protective effects of BML-111 against acetaminophen-induced acute liver injury in mice. J Physiol Biochem 2013; 70:141-9. [DOI: 10.1007/s13105-013-0288-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 09/05/2013] [Indexed: 10/26/2022]
|
63
|
Smeyne M, Smeyne RJ. Glutathione metabolism and Parkinson's disease. Free Radic Biol Med 2013; 62:13-25. [PMID: 23665395 PMCID: PMC3736736 DOI: 10.1016/j.freeradbiomed.2013.05.001] [Citation(s) in RCA: 311] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 05/01/2013] [Accepted: 05/01/2013] [Indexed: 12/14/2022]
Abstract
It has been established that oxidative stress, defined as the condition in which the sum of free radicals in a cell exceeds the antioxidant capacity of the cell, contributes to the pathogenesis of Parkinson disease. Glutathione is a ubiquitous thiol tripeptide that acts alone or in concert with enzymes within cells to reduce superoxide radicals, hydroxyl radicals, and peroxynitrites. In this review, we examine the synthesis, metabolism, and functional interactions of glutathione and discuss how these relate to the protection of dopaminergic neurons from oxidative damage and its therapeutic potential in Parkinson disease.
Collapse
Affiliation(s)
- Michelle Smeyne
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, 901-595-3066
| | - Richard Jay Smeyne
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, 901-595-2830
| |
Collapse
|
64
|
Roušar T, Nýdlová E, Česla P, Staňková P, Kučera O, Pařík P, Červinková Z. Purified acetaminophen-glutathione conjugate is able to induce oxidative stress in rat liver mitochondria. Physiol Res 2013; 61:S103-9. [PMID: 23130894 DOI: 10.33549/physiolres.932427] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Acetaminophen overdose is the most often cause of acute liver injury. The toxic mechanism is linked to formation of an active metabolite that reacts with glutathione generating acetaminophen-glutathione conjugate (APAP-SG). This compound has been recognized to be non-toxic generally. Our preliminary results showed, however, that APAP-SG could possess a toxic effect too. Therefore, the aim of our study was to prepare, purify and to test possible toxicity of APAP-SG. We prepared APAP-SG using organic synthesis. The conjugate was purified by preparative HPLC and its structure was confirmed using mass spectrometry. Final purity of APAP-SG was >98 %. We estimated a toxic effect of APAP-SG in isolated rat liver mitochondria using a fluorescent ROS probe. We assessed ROS production in presence of complex I or complex II substrates. The increase of ROS-dependent fluorescence in presence of glutamate/malate was 104 ± 13 % and 130 ± 10 % in 1 mM and 5 mM APAP-SG, respectively, in comparison with controls. ROS production related to presence of complex II substrate was enhanced 4-times in APAP-SG (5 mM) treated mitochondria (compared to controls). We conclude, we proved our hypothesis that APAP-SG conjugate is able to induce a mitochondrial impairment leading to enhanced ROS production.
Collapse
Affiliation(s)
- T Roušar
- Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic.
| | | | | | | | | | | | | |
Collapse
|
65
|
Arakawa S. Utilization ofglutathione S-transferase Mu 1- andTheta 1-null mice as animal models for absorption, distribution, metabolism, excretion and toxicity studies. Expert Opin Drug Metab Toxicol 2013; 9:725-36. [DOI: 10.1517/17425255.2013.780027] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
66
|
McGill MR, Jaeschke H. Metabolism and disposition of acetaminophen: recent advances in relation to hepatotoxicity and diagnosis. Pharm Res 2013; 30:2174-87. [PMID: 23462933 DOI: 10.1007/s11095-013-1007-6] [Citation(s) in RCA: 445] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 02/06/2013] [Indexed: 12/11/2022]
Abstract
Acetaminophen (APAP) is one of the most widely used drugs. Though safe at therapeutic doses, overdose causes mitochondrial dysfunction and centrilobular necrosis in the liver. The first studies of APAP metabolism and activation were published more than 40 years ago. Most of the drug is eliminated by glucuronidation and sulfation. These reactions are catalyzed by UDP-glucuronosyltransferases (UGT1A1 and 1A6) and sulfotransferases (SULT1A1, 1A3/4, and 1E1), respectively. However, some is converted by CYP2E1 and other cytochrome P450 enzymes to a reactive intermediate that can bind to sulfhydryl groups. The metabolite can deplete liver glutathione (GSH) and modify cellular proteins. GSH binding occurs spontaneously, but may also involve GSH-S-transferases. Protein binding leads to oxidative stress and mitochondrial damage. The glucuronide, sulfate, and GSH conjugates are excreted by transporters in the canalicular (Mrp2 and Bcrp) and basolateral (Mrp3 and Mrp4) hepatocyte membranes. Conditions that interfere with metabolism and metabolic activation can alter the hepatotoxicity of the drug. Recent data providing novel insights into these processes, particularly in humans, are reviewed in the context of earlier work, and the effects of altered metabolism and reactive metabolite formation are discussed. Recent advances in the diagnostic use of serum adducts are covered.
Collapse
Affiliation(s)
- Mitchell R McGill
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd, MS 1018, Kansas City, Kansas 66160, USA
| | | |
Collapse
|
67
|
Diaz Ochoa JG, Bucher J, Péry ARR, Zaldivar Comenges JM, Niklas J, Mauch K. A multi-scale modeling framework for individualized, spatiotemporal prediction of drug effects and toxicological risk. Front Pharmacol 2013; 3:204. [PMID: 23346056 PMCID: PMC3551257 DOI: 10.3389/fphar.2012.00204] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 12/17/2012] [Indexed: 12/14/2022] Open
Abstract
In this study, we focus on a novel multi-scale modeling approach for spatiotemporal prediction of the distribution of substances and resulting hepatotoxicity by combining cellular models, a 2D liver model, and whole body model. As a case study, we focused on predicting human hepatotoxicity upon treatment with acetaminophen based on in vitro toxicity data and potential inter-individual variability in gene expression and enzyme activities. By aggregating mechanistic, genome-based in silico cells to a novel 2D liver model and eventually to a whole body model, we predicted pharmacokinetic properties, metabolism, and the onset of hepatotoxicity in an in silico patient. Depending on the concentration of acetaminophen in the liver and the accumulation of toxic metabolites, cell integrity in the liver as a function of space and time as well as changes in the elimination rate of substances were estimated. We show that the variations in elimination rates also influence the distribution of acetaminophen and its metabolites in the whole body. Our results are in agreement with experimental results. What is more, the integrated model also predicted variations in drug toxicity depending on alterations of metabolic enzyme activities. Variations in enzyme activity, in turn, reflect genetic characteristics or diseases of individuals. In conclusion, this framework presents an important basis for efficiently integrating inter-individual variability data into models, paving the way for personalized or stratified predictions of drug toxicity and efficacy.
Collapse
|
68
|
Kohonen P, Benfenati E, Bower D, Ceder R, Crump M, Cross K, Grafström RC, Healy L, Helma C, Jeliazkova N, Jeliazkov V, Maggioni S, Miller S, Myatt G, Rautenberg M, Stacey G, Willighagen E, Wiseman J, Hardy B. The ToxBank Data Warehouse: Supporting the Replacement of In Vivo Repeated Dose Systemic Toxicity Testing. Mol Inform 2013; 32:47-63. [PMID: 27481023 DOI: 10.1002/minf.201200114] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 11/27/2012] [Indexed: 12/12/2022]
Abstract
The aim of the SEURAT-1 (Safety Evaluation Ultimately Replacing Animal Testing-1) research cluster, comprised of seven EU FP7 Health projects co-financed by Cosmetics Europe, is to generate a proof-of-concept to show how the latest technologies, systems toxicology and toxicogenomics can be combined to deliver a test replacement for repeated dose systemic toxicity testing on animals. The SEURAT-1 strategy is to adopt a mode-of-action framework to describe repeated dose toxicity, combining in vitro and in silico methods to derive predictions of in vivo toxicity responses. ToxBank is the cross-cluster infrastructure project whose activities include the development of a data warehouse to provide a web-accessible shared repository of research data and protocols, a physical compounds repository, reference or "gold compounds" for use across the cluster (available via wiki.toxbank.net), and a reference resource for biomaterials. Core technologies used in the data warehouse include the ISA-Tab universal data exchange format, REpresentational State Transfer (REST) web services, the W3C Resource Description Framework (RDF) and the OpenTox standards. We describe the design of the data warehouse based on cluster requirements, the implementation based on open standards, and finally the underlying concepts and initial results of a data analysis utilizing public data related to the gold compounds.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Lyn Healy
- National Institute for Biological Standards and Control, Potters Bar, UK
| | | | | | | | - Silvia Maggioni
- Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | | | | | | | - Glyn Stacey
- National Institute for Biological Standards and Control, Potters Bar, UK
| | | | | | | |
Collapse
|
69
|
Stachulski AV, Baillie TA, Kevin Park B, Scott Obach R, Dalvie DK, Williams DP, Srivastava A, Regan SL, Antoine DJ, Goldring CEP, Chia AJL, Kitteringham NR, Randle LE, Callan H, Castrejon JL, Farrell J, Naisbitt DJ, Lennard MS. The Generation, Detection, and Effects of Reactive Drug Metabolites. Med Res Rev 2012; 33:985-1080. [DOI: 10.1002/med.21273] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Andrew V. Stachulski
- Department of Chemistry, Robert Robinson Laboratories; University of Liverpool; Liverpool; L69 7ZD; UK
| | - Thomas A. Baillie
- School of Pharmacy; University of Washington; Box 357631; Seattle; Washington; 98195-7631
| | - B. Kevin Park
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - R. Scott Obach
- Pharmacokinetics, Dynamics and Metabolism; Pfizer Worldwide Research & Development; Groton; Connecticut 06340
| | - Deepak K. Dalvie
- Pharmacokinetics, Dynamics and Metabolism; Pfizer Worldwide Research & Development; La Jolla; California 94121
| | - Dominic P. Williams
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Abhishek Srivastava
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Sophie L. Regan
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Daniel J. Antoine
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Christopher E. P. Goldring
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Alvin J. L. Chia
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Neil R. Kitteringham
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Laura E. Randle
- School of Pharmacy and Biomolecular Sciences, Faculty of Science; Liverpool John Moores University; James Parsons Building, Byrom Street; Liverpool L3 3AF; UK
| | - Hayley Callan
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - J. Luis Castrejon
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - John Farrell
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Dean J. Naisbitt
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Martin S. Lennard
- Academic Unit of Medical Education; University of Sheffield; 85 Wilkinson Street; Sheffield S10 2GJ; UK
| |
Collapse
|
70
|
Arakawa S, Maejima T, Fujimoto K, Yamaguchi T, Yagi M, Sugiura T, Atsumi R, Yamazoe Y. Resistance to acetaminophen-induced hepatotoxicity in glutathione S-transferase Mu 1-null mice. J Toxicol Sci 2012; 37:595-605. [PMID: 22687999 DOI: 10.2131/jts.37.595] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We investigated the role of glutathione S-transferases Mu 1 (GSTM1) in acetaminophen (APAP)-induced hepatotoxicity using Gstm1-null mice. A single oral administration of APAP resulted in a marked increase in plasma alanine aminotransferase accompanied by hepatocyte necrosis 24 hr after administration in wild-type mice, but its magnitude was unexpectedly attenuated in Gstm1-null mice. Therefore, it is suggested that Gstm1-null mice are resistant to APAP-induced hepatotoxicity. To examine the mechanism of this resistance in Gstm1-null mice, we measured phosphorylation of c-jun N-terminal kinase (JNK), which mediates the signal of APAP-induced hepatocyte necrosis, by Western blot analysis 2 and 6 hr after APAP administration. A marked increase in phosphorylated JNK was observed in wild-type mice, but the increase was markedly suppressed in Gstm1-null mice. Therefore, it is suggested that suppressed phosphorylation of JNK may be a main mechanism of the resistance to APAP-induced hepatotoxicity in Gstm1-null mice, although other possibilities of the mechanism cannot be eliminated. Additionally, phosphorylation of glycogen synthase kinase-3β and mitogen-activated protein kinase kinase 4, which are upstream kinases of JNK in APAP-induced hepatotoxicity, were also suppressed in Gstm1-null mice. A decrease in liver total glutathione 2 hr after APAP administration, which is an indicator for exposure to N-acetyl-p-benzoquinoneimine, the reactive metabolite of APAP, were similar in wild-type and Gstm1-null mice. In conclusion, Gstm1-null mice are considered to be resistant to APAP-induced hepatotoxicity perhaps by the suppression of JNK phosphorylation. This study indicates the novel role of GSTM1 as a factor mediating the cellular signal for APAP-induced hepatotoxicity.
Collapse
Affiliation(s)
- Shingo Arakawa
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd, Shizuoka, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
71
|
Irving RM, Elfarra AA. Role of reactive metabolites in the circulation in extrahepatic toxicity. Expert Opin Drug Metab Toxicol 2012; 8:1157-72. [PMID: 22681489 DOI: 10.1517/17425255.2012.695347] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Reactive metabolite-mediated toxicity is frequently limited to the organ where the electrophilic metabolites are generated. Some reactive metabolites, however, might have the ability to translocate from their site of formation. This suggests that for these reactive metabolites, investigations into the role of organs other than the one directly affected could be relevant to understanding the mechanism of toxicity. AREAS COVERED The authors discuss the physiological and biochemical factors that can enable reactive metabolites to cause toxicity in an organ distal from the site of generation. Furthermore, the authors present a case study which describes studies that demonstrate that S-(1,2-dichlorovinyl)-L-cysteine sulfoxide (DCVCS) and N-acetyl-S-(1,2-dichlorovinyl-L-cysteine sulfoxide (N-AcDCVCS), reactive metabolites of the known trichloroethylene metabolites S-(1,2-dichlorovinyl)-L-cysteine (DCVC), and N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine (N-AcDCVC), are generated in the liver and translocate through the circulation to the kidney to cause nephrotoxicity. EXPERT OPINION The ability of reactive metabolites to translocate could be important to consider when investigating mechanisms of toxicity. A mechanistic approach, similar to the one described for DCVCS and N-AcDCVCS, could be useful in determining the role of circulating reactive metabolites in extrahepatic toxicity of drugs and other chemicals. If this is the case, intervention strategies that would not otherwise be feasible might be effective for reducing extrahepatic toxicity.
Collapse
Affiliation(s)
- Roy M Irving
- University of Wisconsin-Madison, School of Veterinary Medicine, Department of Comparative Biosciences and Molecular and Environmental Toxicology Center, Madison, WI 53706, USA
| | | |
Collapse
|
72
|
Saini SP, Zhang B, Niu Y, Jiang M, Gao J, Zhai Y, Lee JH, Uppal H, Tian H, Tortorici MA, Poloyac SM, Qin W, Venkataramanan R, Xie W. Activation of liver X receptor increases acetaminophen clearance and prevents its toxicity in mice. Hepatology 2011; 54:2208-17. [PMID: 21898498 PMCID: PMC3230770 DOI: 10.1002/hep.24646] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
UNLABELLED Overdose of acetaminophen (APAP), the active ingredient of Tylenol, is the leading cause of drug-induced acute liver failure in the United States. As such, it is necessary to develop novel strategies to prevent or manage APAP toxicity. In this report, we reveal a novel function of the liver X receptor (LXR) in preventing APAP-induced hepatotoxicity. Activation of LXR in transgenic (Tg) mice or by an LXR agonist conferred resistance to the hepatotoxicity of APAP, whereas the effect of LXR agonist on APAP toxicity was abolished in LXR-deficient mice. The increased APAP resistance in LXR Tg mice was associated with increased APAP clearance, increased APAP sulfation, and decreased formation of toxic APAP metabolites. The hepatoprotective effect of LXR may have resulted from the induction of antitoxic phase II conjugating enzymes, such as Gst and Sult2a1, as well as the suppression of protoxic phase I P450 enzymes, such as Cyp3a11 and Cyp2e1. Promoter analysis suggested the mouse Gst isoforms as novel transcriptional targets of LXR. The suppression of Cyp3a11 may be accounted for by the inhibitory effect of LXR on the PXR-responsive transactivation of Cyp3a11. The protective effect of LXR in preventing APAP toxicity is opposite to the sensitizing effect of pregnane X receptor, constitutive androstane receptor, and retinoid X receptor alpha. CONCLUSION We conclude that LXR represents a potential therapeutic target for the prevention and treatment of Tylenol toxicity.
Collapse
Affiliation(s)
- Simrat P.S. Saini
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Bin Zhang
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Yongdong Niu
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261,State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China
| | - Mengxi Jiang
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Jie Gao
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Yonggong Zhai
- Key Laboratory for Cell Proliferation and Regulation Biology, Ministry of Education, Beijing Normal University, Beijing 100875, China
| | - Jung Hoon Lee
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Hirdesh Uppal
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Hui Tian
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Michael A. Tortorici
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Samuel M. Poloyac
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Wenxin Qin
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China
| | - Raman Venkataramanan
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| | - Wen Xie
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261
| |
Collapse
|
73
|
Vaughn MP, Biswal Shinohara D, Castagna N, Hicks JL, Netto G, De Marzo AM, Speed TJ, Reichert ZR, Kwabi-Addo B, Henderson CJ, Wolf CR, Yegnasubramanian S, Nelson WG. Humanizing π-class glutathione S-transferase regulation in a mouse model alters liver toxicity in response to acetaminophen overdose. PLoS One 2011; 6:e25707. [PMID: 22022436 PMCID: PMC3191143 DOI: 10.1371/journal.pone.0025707] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 09/08/2011] [Indexed: 12/31/2022] Open
Abstract
Background Glutathione S-transferases (GSTs) metabolize drugs and xenobiotics. Yet despite high protein sequence homology, expression of π-class GSTs, the most abundant of the enzymes, varies significantly between species. In mouse liver, hepatocytes exhibit high mGstp expression, while in human liver, hepatocytes contain little or no hGSTP1 mRNA or hGSTP1 protein. π-class GSTs are known to be critical determinants of liver responses to drugs and toxins: when treated with high doses of acetaminophen, mGstp1/2+/+ mice suffer marked liver damage, while mGstp1/2−/− mice escape liver injury. Methodology/Principal Findings To more faithfully model the contribution of π-class GSTs to human liver toxicology, we introduced hGSTP1, with its exons, introns, and flanking sequences, into the germline of mice carrying disrupted mGstp genes. In the resultant hGSTP1+mGstp1/2−/− strain, π-class GSTs were regulated differently than in wild-type mice. In the liver, enzyme expression was restricted to bile duct cells, Kupffer cells, macrophages, and endothelial cells, reminiscent of human liver, while in the prostate, enzyme production was limited to basal epithelial cells, reminiscent of human prostate. The human patterns of hGSTP1 transgene regulation were accompanied by human patterns of DNA methylation, with bisulfite genomic sequencing revealing establishment of an unmethylated CpG island sequence encompassing the gene promoter. Unlike wild-type or mGstp1/2−/− mice, when hGSTP1+mGstp1/2−/− mice were overdosed with acetaminophen, liver tissues showed limited centrilobular necrosis, suggesting that π-class GSTs may be critical determinants of toxin-induced hepatocyte injury even when not expressed by hepatocytes. Conclusions By recapitulating human π-class GST expression, hGSTP1+mGstp1/2−/− mice may better model human drug and xenobiotic toxicology.
Collapse
Affiliation(s)
- Matthew P. Vaughn
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Debika Biswal Shinohara
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Nicole Castagna
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jessica L. Hicks
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - George Netto
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Angelo M. De Marzo
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Traci J. Speed
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Zachery R. Reichert
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Bernard Kwabi-Addo
- Howard University Cancer Center, Howard University, Washington, District of Columbia, United States of America
| | - Colin J. Henderson
- Cancer Research United Kingdom Molecular Pharmacology Unit, Biomedical Research Institute, Ninewells Hospital and Medical School, Dundee, United Kingdom
| | - C. Roland Wolf
- Cancer Research United Kingdom Molecular Pharmacology Unit, Biomedical Research Institute, Ninewells Hospital and Medical School, Dundee, United Kingdom
| | - Srinivasan Yegnasubramanian
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail: (SY); (WN)
| | - William G. Nelson
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail: (SY); (WN)
| |
Collapse
|
74
|
Nakayama S, Takakusa H, Watanabe A, Miyaji Y, Suzuki W, Sugiyama D, Shiosakai K, Honda K, Okudaira N, Izumi T, Okazaki O. Combination of GSH Trapping and Time-Dependent Inhibition Assays as a Predictive Method of Drugs Generating Highly Reactive Metabolites. Drug Metab Dispos 2011; 39:1247-54. [DOI: 10.1124/dmd.111.039180] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
|
75
|
Park BK, Boobis A, Clarke S, Goldring CEP, Jones D, Kenna JG, Lambert C, Laverty HG, Naisbitt DJ, Nelson S, Nicoll-Griffith DA, Obach RS, Routledge P, Smith DA, Tweedie DJ, Vermeulen N, Williams DP, Wilson ID, Baillie TA. Managing the challenge of chemically reactive metabolites in drug development. Nat Rev Drug Discov 2011; 10:292-306. [DOI: 10.1038/nrd3408] [Citation(s) in RCA: 355] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
76
|
Abstract
Glutathione transferases (GSTs) are a multigene family of ubiquitously expressed, polymorphic enzymes responsible for the metabolism of a wide range of both endogenous and exogenous substrates, play a central role in the adaptive response to chemical and oxidative stress, and are subject to regulation by a range of structurally unrelated chemicals. In this review, we present a current summary of knockout mouse models in the GST field, discussing some of the issues pertaining to orthologous proteins between mice and humans, the potential confounding issues related to genetic background, and also cover new transgenic models in the increasingly important area of humanization.
Collapse
Affiliation(s)
- Colin J Henderson
- Cancer Research UK, Molecular Pharmacology Group, Biomedical Research Institute, University of Dundee College of Medicine Dentistry and Nursing, Ninewells Hospital, Dundee, United Kingdom.
| | | |
Collapse
|
77
|
Dragovic S, Boerma JS, van Bergen L, Vermeulen NPE, Commandeur JNM. Role of human glutathione S-transferases in the inactivation of reactive metabolites of clozapine. Chem Res Toxicol 2011; 23:1467-76. [PMID: 20849150 DOI: 10.1021/tx100131f] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The conjugation of reactive drug metabolites to GSH is considered an important detoxification mechanism that can be spontaneous and/or mediated by glutathione S-transferases (GSTs). In case GSTs play an important role in GSH conjugation, genetically determined deficiencies in GSTs may be a risk factor for adverse drug reactions (ADRs) resulting from reactive drug metabolites. So far, the role of GSTs in the detoxification of reactive intermediates of clozapine, a drug-causing idiosyncratic drug reactions (IDRs), has not been studied. In the present study, we studied the ability of four recombinant human GSTs (hGST A1-1, hGST M1-1, hGST P1-1, and hGST T1-1) to catalyze the GSH conjugation of reactive metabolites of clozapine, formed in vitro by human and rat liver microsomes and drug-metabolizing P450 BM3 mutant, P450 102A1M11H. Consistent with previous studies, in the absence of GSTs, three GSH conjugates were identified derived from the nitrenium ion of clozapine. In the presence of three of the GSTs, hGST P1-1, hGST M1-1, and hGST A1-1, total GSH conjugation was strongly increased in all bioactivation systems tested. The highest activity was observed with hGST P1-1, whereas hGST M1-1 and hGST A1-1 showed slightly lower activity. Polymorphic hGST T1-1 did not show any activity in catalyzing GSH conjugation of reactive clozapine metabolites. Interestingly, the addition of hGSTs resulted in major changes in the regioselectivity of GSH conjugation of the reactive clozapine metabolite, possibly due to the different active site geometries of hGSTs. Two GSH conjugates found were completely dependent on the presence of hGSTs. Chlorine substitution of the clozapine nitrenium ion, which so far was only observed in in vivo studies, appeared to be the major pathway of hGST P1-1-catalyzed GSH conjugation, whereas hGST A1-1 and hGST M1-1 also showed significant activity. The second GSH conjugate, previously also only found in in vivo studies, was also formed by hGST P1-1 and to a small extent by hGST A1-1. These results demonstrate that human GSTs may play a significant role in the inactivation of reactive intermediates of clozapine. Therefore, further studies are required to investigate whether genetic polymorphisms of hGST P1-1 and hGST M1-1 contribute to the interindividual differences in susceptibility to clozapine-induced adverse drug reactions.
Collapse
Affiliation(s)
- Sanja Dragovic
- Division of Molecular Toxicology, LACDR, Leiden/Amsterdam Center for Drug Research, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | | | | | | | | |
Collapse
|
78
|
Moyer AM, Fridley BL, Jenkins GD, Batzler AJ, Pelleymounter LL, Kalari KR, Ji Y, Chai Y, Nordgren KKS, Weinshilboum RM. Acetaminophen-NAPQI hepatotoxicity: a cell line model system genome-wide association study. Toxicol Sci 2010; 120:33-41. [PMID: 21177773 DOI: 10.1093/toxsci/kfq375] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Acetaminophen is the leading cause of acute hepatic failure in many developed nations. Acetaminophen hepatotoxicity is mediated by the reactive metabolite N-acetyl-p-benzoquinonimine (NAPQI). We performed a "discovery" genome-wide association study using a cell line-based model system to study the possible contribution of genomics to NAPQI-induced cytotoxicity. A total of 176 lymphoblastoid cell lines from healthy subjects were treated with increasing concentrations of NAPQI. Inhibiting concentration 50 values were determined and were associated with "glutathione pathway" gene single nucleotide polymorphisms (SNPs) and genome-wide basal messenger RNA expression, as well as with 1.3 million genome-wide SNPs. A group of SNPs in linkage disequilibrium on chromosome 3 was highly associated with NAPQI toxicity. The p value for rs2880961, the SNP with the lowest p value, was 1.88 × 10(-7). This group of SNPs mapped to a "gene desert," but chromatin immunoprecipitation assays demonstrated binding of several transcription factor proteins including heat shock factor 1 (HSF1) and HSF2, at or near rs2880961. These chromosome 3 SNPs were not significantly associated with variation in basal expression for any of the genome-wide genes represented on the Affymetrix U133 Plus 2.0 GeneChip. We have used a cell line-based model system to identify a SNP signal associated with NAPQI cytotoxicity. If these observations are validated in future clinical studies, this SNP signal might represent a potential biomarker for risk of acetaminophen hepatotoxicity. The mechanisms responsible for this association remain unclear.
Collapse
Affiliation(s)
- Ann M Moyer
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
79
|
Abstract
Paracetamol (acetaminophen) is a worldwide used analgesic and antipyretic drug. It is metabolised via several metabolic pathways, including glucuronidation, sulfation, oxidation, hydroxylation, and deacetylation: Hepatic and other organ damage may occur, especially in overdose, because of the accumulation of a toxic metabolite. Intersubject and ethnic differences have been reported in paracetamol metabolism activation, suggesting possible differences in susceptibility to toxicity and in pain alleviation, linked to different pharmacogenetic profiles. This article aims at reviewing, in the literature, the links between paracetamol metabolism and enzyme genotypes in the context of toxic side effects and efficacy of paracetamol in therapeutics.
Collapse
Affiliation(s)
- Lizi Zhao
- Institute of Clinical Pharmacology, Sun Yat-Sen University, Guangzhou, China
| | | |
Collapse
|
80
|
Shaheen SO, Newson RB, Ring SM, Rose-Zerilli MJ, Holloway JW, Henderson AJ. Prenatal and infant acetaminophen exposure, antioxidant gene polymorphisms, and childhood asthma. J Allergy Clin Immunol 2010; 126:1141-8.e7. [PMID: 21051083 DOI: 10.1016/j.jaci.2010.08.047] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Revised: 08/25/2010] [Accepted: 08/26/2010] [Indexed: 01/12/2023]
Abstract
BACKGROUND Prenatal and infant acetaminophen exposure has been associated with an increased risk of childhood asthma phenotypes. Demonstration of biologically plausible interactions between these exposures and maternal and child antioxidant gene polymorphisms would strengthen causal inference. OBJECTIVE To explore potential interactions between prenatal and infant acetaminophen exposure and antioxidant genotypes on childhood asthma. METHODS In the Avon Longitudinal Study of Parents and Children, we typed a functional nuclear erythroid 2 p45-related factor 2 (Nrf2) polymorphism and glutathione S-transferase (GST) M1, T1, and P1 polymorphisms. Effects of prenatal and infant acetaminophen exposure on asthma phenotypes at 7 years were stratified by genotype in >4000 mothers and >5000 children. RESULTS Risk of asthma and wheezing associated with early gestation acetaminophen exposure was increased when maternal copies of the minor T allele of Nrf2 were present (P interactions, .02 and .04, respectively). Risk of asthma associated with late gestation exposure was higher when maternal GSTT1 genotype was present rather than absent (P interaction, .006), and risk of wheezing was increased when maternal GSTM1 was present (P interaction, .04). Although acetaminophen use in infancy was associated with an increased risk of atopy, child antioxidant genotype did not modify associations between infant acetaminophen use and asthma phenotypes. However, the increased risk of asthma and wheezing associated with late gestation acetaminophen exposure in the presence of maternal GSTM1 was further enhanced when GSTM1 was also present in the child. CONCLUSION Maternal antioxidant gene polymorphisms may modify the relation between prenatal acetaminophen exposure and childhood asthma, strengthening evidence for a causal association. In contrast, relations between infant acetaminophen use and asthma and atopy were not modified by child genotype and may be confounded by pre-existing wheeze or allergy.
Collapse
Affiliation(s)
- Seif O Shaheen
- Respiratory Epidemiology and Public Health Group, National Heart and Lung Institute, Imperial College London, London, United Kingdom.
| | | | | | | | | | | |
Collapse
|
81
|
Park BK, Laverty H, Srivastava A, Antoine DJ, Naisbitt D, Williams DP. Drug bioactivation and protein adduct formation in the pathogenesis of drug-induced toxicity. Chem Biol Interact 2010; 192:30-6. [PMID: 20846520 DOI: 10.1016/j.cbi.2010.09.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 09/06/2010] [Accepted: 09/07/2010] [Indexed: 02/06/2023]
Abstract
Adverse drug reactions (ADRs) remain a major complication of drug therapy and can be classified as 'on-target' or 'off-target' (idiosyncratic) reactions. On-target reactions can be predicted from the known primary or secondary pharmacology of the drug and often represent an exaggeration of the pharmacological effect of the drug. In contrast, off-target adverse reactions cannot be predicted from knowledge of the basic pharmacology of the drug. The exact mechanisms of idiosyncratic drug reactions are still unclear; however it is believed that they can be initiated by chemically reactive drug metabolites. It is well known that xenobiotics can undergo metabolic bioactivation reactions which have the potential to cause cellular stress and damage. Bioactivation of drugs is thought to have the potential of initiating covalent linkages between cellular protein and drugs which can be recognised by the adaptive immune system in the absence of detectable cellular stress. This process cannot yet be predicted in pre-clinical models or discovered in clinical trials. Because of this hazard perception, the formation of chemically reactive metabolites in early drug discovery remains a serious impediment to the development of new medicines and can lead to withdrawal of an otherwise effective therapeutic agent. The fear of such reactions occurring at the post-licensing stage - when such problems first become evident - is a major contribution to drug attrition. The first step towards such methodology has been the development of chemically reactive metabolite screens. The chemical basis of drug bioactivation can usually be rationalised and synthetic strategies put in place to prevent such bioactivation. However, there is no simple correlation between drug bioactivation in vitro and adverse drug reactions in the clinic. Such a chemical approach is clearly limited by the facts that (a) not all drugs that can undergo bioactivation by human drug-metabolising enzymes are associated with hypersensitivity in the clinic and (b) drug bioactivation may not always be a mandatory step in drug hypersensitivity. To predict such reactions in early drug development, it will require an integrated understanding of the chemical, immunological and genetic basis of adverse drug reactions in patients, which in turn will depend on the development of novel in vitro experimental systems.
Collapse
Affiliation(s)
- B K Park
- MRC Centre for Drug Safety Science, Institute of Translational Medicine, Department of Molecular and Clinical Pharmacology, University of Liverpool, Sherrington Buildings, Ashton Street, Liverpool L69 3GE, UK.
| | | | | | | | | | | |
Collapse
|
82
|
Josephy PD. Genetic variations in human glutathione transferase enzymes: significance for pharmacology and toxicology. HUMAN GENOMICS AND PROTEOMICS : HGP 2010; 2010:876940. [PMID: 20981235 PMCID: PMC2958679 DOI: 10.4061/2010/876940] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 03/22/2010] [Indexed: 01/21/2023]
Abstract
Glutathione transferase enzymes (GSTs) catalyze reactions in which electrophiles are conjugated to the tripeptide thiol glutathione. While many GST-catalyzed transformations result in the detoxication of xenobiotics, a few substrates, such as dihaloalkanes, undergo bioactivation to reactive intermediates. Many molecular epidemiological studies have tested associations between polymorphisms (especially, deletions) of human GST genes and disease susceptibility or response to therapy. This review presents a discussion of the biochemistry of GSTs, the sources-both genetic and environmental-of interindividual variation in GST activities, and their implications for pharmaco- and toxicogenetics; particular attention is paid to the Theta class GSTs.
Collapse
Affiliation(s)
- P David Josephy
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| |
Collapse
|
83
|
Stamper BD, Bammler TK, Beyer RP, Farin FM, Nelson SD. Differential regulation of mitogen-activated protein kinase pathways by acetaminophen and its nonhepatotoxic regioisomer 3'-hydroxyacetanilide in TAMH cells. Toxicol Sci 2010; 116:164-73. [PMID: 20363829 DOI: 10.1093/toxsci/kfq100] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Acetaminophen (APAP), a widely used analgesic and antipyretic that is considered to be relatively safe at recommended doses, is the leading cause of drug-induced liver failure in the United States. 3'-Hydroxyacetanilide (AMAP), a regioisomer of APAP, is useful as a comparative tool for studying APAP-induced toxicity because it is nontoxic relative to APAP. Transforming growth factor-alpha transgenic mouse hepatocytes were treated with both isomers to investigate mitogen-activated protein kinase (MAPK) cascades in order to differentiate their toxicological outcomes. Posttranslational modifications of MAPK signaling were assessed using immunoblotting and Bioplex technology, whereas gene expression changes were measured using Affymetrix Mouse Gene 1.0 ST arrays. APAP treatment led to higher levels of glutathione depletion at 6 and 24 h compared with AMAP in mitochondria. Glutathione depletion was preceded by increased levels of c-Jun N-terminal kinase (JNK) phosphorylation at 2 and 6 h after APAP treatment compared with AMAP, whereas AMAP treatment led to increased extracellular signal-regulated protein kinase (ERK) phosphorylation at 2 and 6 h compared with APAP. Furthermore, APAP treatment significantly upregulated jun oncogene (c-Jun) gene expression, which was confirmed by Western blotting for both the phosphorylated and the nonphosphorylated forms of c-Jun protein. Transfection with JNK siRNA attenuated APAP toxicity after 24 h, suggesting that higher levels of APAP-induced activation of JNK were related to higher rates of cell death. In summary, genomic regulation of MAPK-related transcription factors coupled with posttranslational activation of their upstream kinases is critical in differentiating the toxicities of APAP and AMAP.
Collapse
Affiliation(s)
- Brendan D Stamper
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, USA
| | | | | | | | | |
Collapse
|
84
|
Abstract
Although considered safe at therapeutic doses, at higher doses, acetaminophen produces a centrilobular hepatic necrosis that can be fatal. Acetaminophen poisoning accounts for approximately one-half of all cases of acute liver failure in the United States and Great Britain today. The mechanism occurs by a complex sequence of events. These events include: (1) CYP metabolism to a reactive metabolite which depletes glutathione and covalently binds to proteins; (2) loss of glutathione with an increased formation of reactive oxygen and nitrogen species in hepatocytes undergoing necrotic changes; (3) increased oxidative stress, associated with alterations in calcium homeostasis and initiation of signal transduction responses, causing mitochondrial permeability transition; (4) mitochondrial permeability transition occurring with additional oxidative stress, loss of mitochondrial membrane potential, and loss of the ability of the mitochondria to synthesize ATP; and (5) loss of ATP which leads to necrosis. Associated with these essential events there appear to be a number of inflammatory mediators such as certain cytokines and chemokines that can modify the toxicity. Some have been shown to alter oxidative stress, but the relationship of these modulators to other critical mechanistic events has not been well delineated. In addition, existing data support the involvement of cytokines, chemokines, and growth factors in the initiation of regenerative processes leading to the reestablishment of hepatic structure and function.
Collapse
Affiliation(s)
- Jack A Hinson
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | | | | |
Collapse
|
85
|
Abstract
Drugs are generally converted to biologically inactive forms and eliminated from the body, principally by hepatic metabolism. However, certain drugs undergo biotransformation to metabolites that can interfere with cellular functions through their intrinsic chemical reactivity towards glutathione, leading to thiol depletion, and functionally critical macromolecules, resulting in reversible modification, irreversible adduct formation, and irreversible loss of activity. There is now a great deal of evidence which shows that reactive metabolites are formed from drugs known to cause hepatotoxicity, such as acetaminophen, tamoxifen, isoniazid, and amodiaquine. The main theme of this article is to review the evidence for chemically reactive metabolites being initiating factors for the multiple downstream biological events culminating in toxicity. The major objectives are to understand those idiosyncratic hepatotoxicities thought to be caused by chemically reactive metabolites and to define the role of toxic metabolites.
Collapse
|
86
|
Perzanowski MS, Miller RL, Tang D, Ali D, Garfinkel RS, Chew GL, Goldstein IF, Perera FP, Barr RG. Prenatal acetaminophen exposure and risk of wheeze at age 5 years in an urban low-income cohort. Thorax 2009. [PMID: 19850963 DOI: 10.1136/thx.2009.121459.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Acetaminophen has been associated with asthma and is in part metabolised via the glutathione pathway. Inner-city minority children have high asthma morbidity and a relatively high frequency of a minor allele variant in the glutathione S transferase Pi gene (GSTP1). We hypothesised that prenatal acetaminophen exposure would predict wheeze at age 5 years in an inner-city minority cohort and examined whether this association was modified by common polymorphisms in genes related to the glutathione pathway. METHODS An ongoing population-based birth cohort study of Dominican Republic and African-American children in New York prospectively assessed the use of analgesics during pregnancy and current wheeze at age 5 years in 301 children. Genotyping was conducted for GST polymorphisms. Binomial regression was used to adjust for potential confounders including postnatal acetaminophen use. RESULTS 34% of mothers reported acetaminophen use during pregnancy and 27% of children had current wheeze at 5 years. Prenatal exposure to acetaminophen predicted current wheeze (multivariate relative risk 1.71; 95% CI 1.20 to 2.42; p=0.003), and the risk increased monotonically with increasing number of days of prenatal acetaminophen exposure (p trend <0.001). 68% of children had at least one copy of the GSTP1 minor allele (Val). The risk of wheeze was modified by GSTP1 (additive interaction p=0.009) and was observed only among children with the GSTP1 minor allele. CONCLUSIONS Prenatal exposure to acetaminophen predicted wheeze at age 5 years in an inner-city minority cohort. The risk was modified by a functional polymorphism in GSTP1, suggesting a mechanism involving the glutathione pathway.
Collapse
Affiliation(s)
- Matthew S Perzanowski
- Columbia Center for Children's Environmental Health (CCCEH), New York, NY 10032, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
87
|
Perzanowski MS, Miller RL, Tang D, Ali D, Garfinkel RS, Chew GL, Goldstein IF, Perera FP, Barr RG. Prenatal acetaminophen exposure and risk of wheeze at age 5 years in an urban low-income cohort. Thorax 2009; 65:118-23. [PMID: 19850963 DOI: 10.1136/thx.2009.121459] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Acetaminophen has been associated with asthma and is in part metabolised via the glutathione pathway. Inner-city minority children have high asthma morbidity and a relatively high frequency of a minor allele variant in the glutathione S transferase Pi gene (GSTP1). We hypothesised that prenatal acetaminophen exposure would predict wheeze at age 5 years in an inner-city minority cohort and examined whether this association was modified by common polymorphisms in genes related to the glutathione pathway. METHODS An ongoing population-based birth cohort study of Dominican Republic and African-American children in New York prospectively assessed the use of analgesics during pregnancy and current wheeze at age 5 years in 301 children. Genotyping was conducted for GST polymorphisms. Binomial regression was used to adjust for potential confounders including postnatal acetaminophen use. RESULTS 34% of mothers reported acetaminophen use during pregnancy and 27% of children had current wheeze at 5 years. Prenatal exposure to acetaminophen predicted current wheeze (multivariate relative risk 1.71; 95% CI 1.20 to 2.42; p=0.003), and the risk increased monotonically with increasing number of days of prenatal acetaminophen exposure (p trend <0.001). 68% of children had at least one copy of the GSTP1 minor allele (Val). The risk of wheeze was modified by GSTP1 (additive interaction p=0.009) and was observed only among children with the GSTP1 minor allele. CONCLUSIONS Prenatal exposure to acetaminophen predicted wheeze at age 5 years in an inner-city minority cohort. The risk was modified by a functional polymorphism in GSTP1, suggesting a mechanism involving the glutathione pathway.
Collapse
Affiliation(s)
- Matthew S Perzanowski
- Columbia Center for Children's Environmental Health (CCCEH), New York, NY 10032, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
88
|
Folkes LK, Christlieb M, Madej E, Stratford MRL, Wardman P. Oxidative Metabolism of Combretastatin A-1 Produces Quinone Intermediates with the Potential To Bind to Nucleophiles and To Enhance Oxidative Stress via Free Radicals. Chem Res Toxicol 2007; 20:1885-94. [DOI: 10.1021/tx7002195] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lisa K. Folkes
- University of Oxford, Gray Cancer Institute, P.O. Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR, United Kingdom
| | - Martin Christlieb
- University of Oxford, Gray Cancer Institute, P.O. Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR, United Kingdom
| | - Edyta Madej
- University of Oxford, Gray Cancer Institute, P.O. Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR, United Kingdom
| | - Michael R. L. Stratford
- University of Oxford, Gray Cancer Institute, P.O. Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR, United Kingdom
| | - Peter Wardman
- University of Oxford, Gray Cancer Institute, P.O. Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR, United Kingdom
| |
Collapse
|
89
|
Lin TH, Ng LT, Yen FL, Lin CC. Hepatoprotective effects of Chai-Hu-Ching-Kan-Tang on acetaminophen-induced acute liver injury in rats. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2007; 35:69-79. [PMID: 17265552 DOI: 10.1142/s0192415x07004631] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Chai-Hu-Ching-Kan-Tang (CHCKT) is one of the traditional Chinese medicine prescriptions commonly used to treat liver diseases. In this study, we evaluated the hepatoprotective effects of aqueous CHCKT extract at various concentrations (125, 250 and 500 mg/kg body weight) on acetaminophen (APAP)-induced acute liver injury in rats. Results showed that CHCKT treatments significantly decreased the level of serum glutamic oxaloacetic transaminase (sGOT) and glutamic pyruvic transaminase (sGPT) in APAP-treated groups. CHCKT also significantly decreased the level of lipid peroxides and increased the activity of antioxidant enzymes (i.e. SOD and GPx). Histopathological observation further confirmed the hepatoprotective activity of CHCKT as indicated by the amelioration in the central necrosis and fatty changes of the liver after APAP induction. Interestingly, the hepatoprotective activity of CHCKT at concentrations 125~500 mg/kg appeared to be as good as 12.5 mg/kg silymarin (a commercial hepatoprotective agent). Taken together, these results suggest that aqueous extract of CHCKT possesses potent hepatoprotective effects agianst APAP-induced liver injury in rats.
Collapse
Affiliation(s)
- Tzu-Hsiang Lin
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC
| | | | | | | |
Collapse
|
90
|
Smeyne M, Boyd J, Raviie Shepherd K, Jiao Y, Pond BB, Hatler M, Wolf R, Henderson C, Smeyne RJ. GSTpi expression mediates dopaminergic neuron sensitivity in experimental parkinsonism. Proc Natl Acad Sci U S A 2007; 104:1977-82. [PMID: 17267597 PMCID: PMC1785361 DOI: 10.1073/pnas.0610978104] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Indexed: 12/21/2022] Open
Abstract
The cause of 95% of Parkinson's disease (PD) cases is unknown. It is hypothesized that PD arises from an interaction of free-radical-generating agents with an underlying genetic susceptibility to these compounds. Here we use the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of parkinsonism to examine the role of a dual function protein, GSTpi, in dopaminergic neuron death. GSTpi is the only GST family member expressed in substantia nigra neurons. GSTpi reduction by pharmacological blockade, RNA inhibition, and gene targeting increases sensitivity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, suggesting that differential expression of GSTpi contributes to the sensitivity to xenobiotics in the substantia nigra and may influence the pathogenesis of reactive oxygen species-induced neurological disorders including PD.
Collapse
Affiliation(s)
- Michelle Smeyne
- *Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105; and
| | - Justin Boyd
- *Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105; and
| | - Kennie Raviie Shepherd
- *Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105; and
| | - Yun Jiao
- *Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105; and
| | - Brooks Barnes Pond
- *Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105; and
| | - Matthew Hatler
- *Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105; and
| | - Roland Wolf
- Cancer Research UK, Molecular Pharmacology Unit, Ninewells Hospital and Medical School, Biomedical Research Centre, Level 5, Dundee DD1 9SY, Scotland, United Kingdom
| | - Colin Henderson
- Cancer Research UK, Molecular Pharmacology Unit, Ninewells Hospital and Medical School, Biomedical Research Centre, Level 5, Dundee DD1 9SY, Scotland, United Kingdom
| | - Richard Jay Smeyne
- *Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105; and
| |
Collapse
|
91
|
Yoon MY, Kim SJ, Lee BH, Chung JH, Kim YC. Effects of dimethylsulfoxide on metabolism and toxicity of acetaminophen in mice. Biol Pharm Bull 2006; 29:1618-24. [PMID: 16880615 DOI: 10.1248/bpb.29.1618] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Effects of dimethylsulfoxide (DMSO) on metabolism and toxicity of acetaminophen (APAP) were examined using male mice. A dose of DMSO (1 ml/kg, i.p.) inhibited the induction of APAP hepatotoxicity almost completely as indicated by changes in serum hepatotoxic parameters. Quantification of major APAP metabolites in plasma showed that APAP-glutathione (GSH), a conjugate generated via metabolic activation of APAP, was reduced significantly while APAP-sulfate and APAP-glucuronide, detoxified metabolites both produced directly from the parent drug, were increased in mice pretreated with DMSO. However, microsomal CYP2E1 activity measured with p-nitrophenol and p-nitroanisole as substrates was increased by DMSO treatment. Generation of APAP-GSH in microsomes from control mice was inhibited by DMSO in a dose-dependent manner. Lineweaver-Burk plot analysis indicated that the inhibition pattern produced by DMSO was competitive in nature. A 10000 g supernatant was reconstituted with the cytosolic fraction and microsomes from DMSO- or saline-treated animals. APAP-GSH production was increased significantly when the cytosolic fraction from saline-treated mice and/or microsomes from DMSO-treated mice were used. The results indicate that DMSO induces the enzyme activity responsible for oxidative metabolism of APAP, but its direct inhibitory effect on the enzymatic interaction with this drug decreases the overall production of a reactive metabolite, resulting in reduction of the hepatotoxicity. It is suggested that DMSO effects on metabolism of a xenobiotic would vary depending on its potential to inhibit the interaction of enzyme(s) and the xenobiotic.
Collapse
Affiliation(s)
- Mi Young Yoon
- College of Pharmacy, Seoul National University, Republic of Korea
| | | | | | | | | |
Collapse
|
92
|
Dai G, He L, Chou N, Wan YJY. Acetaminophen metabolism does not contribute to gender difference in its hepatotoxicity in mouse. Toxicol Sci 2006; 92:33-41. [PMID: 16611625 DOI: 10.1093/toxsci/kfj192] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Gender is an important factor in pharmacokinetics and pharmacodynamics. In the current study, gender difference in acetaminophen (APAP)-induced hepatotoxicity has been examined. Male and female mice were injected with a toxic dose of APAP (500 mg/kg, ip). Female mice were resistant to the hepatotoxic effects of APAP, depicted by serum alanine aminotransferase and sorbital dehydrogenase activities and histological analysis. Basal hepatic reduced glutathione (GSH) levels were lower in females than in males, suggesting that basal GSH level may not be a factor in determining the gender difference of APAP hepatotoxicity. APAP metabolism was slower in females than males, revealed by lower levels of glucuronidation and sulfation and higher amounts of free APAP in the livers of female mice. Lower basal Cyp1a2 mRNA levels and lower expression of Cyp1a2 and Cyp3a11 mRNAs after APAP dosing were also observed in females compared with males. However, there was no gender difference in N-acetyl-p-benzoquinone imine covalent binding 2 h after APAP administration, suggesting similar APAP bioactivation between genders. Moreover, liver Gst pi mRNA levels were significantly lower in females than males. This finding is consistent with a previous report, which showed that Gst pi knockout mice are protected from APAP-induced liver toxicity. In conclusion, gender difference of APAP-induced hepatotoxicity is not likely due to APAP metabolism. Perhaps, it is in part due to gender-dependent Gst pi expression. However, the mechanism underlying the association between reduction in Gst pi expression and hepatoprotective effect against APAP toxicity remains to be further explored.
Collapse
Affiliation(s)
- Guoli Dai
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | | | | | | |
Collapse
|
93
|
Abstract
The history of the development of the analgestic drug acetaminophen is reviewed with an emphasis on the characteristics of its overdose toxicity. The P450-catalyzed oxidation of acetaminophen generates a reactive electrophile that binds covalently to proteins. Involvement of specific P450 enzymes in acetaminophen toxicity can be probed by experiments with knock-out mice. The identification of specific target proteins may help to clarify the mechanism of acetaminophen hepatoxocity.
Collapse
Affiliation(s)
- P David Josephy
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
| |
Collapse
|
94
|
Blackburn AC, Matthaei KI, Lim C, Taylor MC, Cappello JY, Hayes JD, Anders MW, Board PG. Deficiency of glutathione transferase zeta causes oxidative stress and activation of antioxidant response pathways. Mol Pharmacol 2005; 69:650-7. [PMID: 16278372 DOI: 10.1124/mol.105.018911] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glutathione S-transferase (GST) zeta (GSTZ1-1) plays a significant role in the catabolism of phenylalanine and tyrosine, and a deficiency of GSTZ1-1 results in the accumulation of maleylacetoacetate and its derivatives maleylacetone (MA) and succinylacetone. Induction of GST subunits was detected in the liver of Gstz1(-/-) mice by Western blotting with specific antisera and high-performance liquid chromatography analysis of glutathione affinity column-purified proteins. The greatest induction was observed in members of the mu class. Induction of NAD(P)H:quinone oxidoreductase 1 and the catalytic and modifier subunits of glutamate-cysteine ligase was also observed. Many of the enzymes that are induced in Gstz1(-/-) mice are regulated by antioxidant response elements that respond to oxidative stress via the Keap1/Nrf2 pathway. It is significant that diminished glutathione concentrations were also observed in the liver of Gstz1(-/-) mice, which supports the conclusion that under normal dietary conditions, the accumulation of electrophilic intermediates such as maleylacetoacetate and MA results in a high level of oxidative stress. Elevated GST activities in the livers of Gstz1(-/-) mice suggest that GSTZ1-1 deficiency may alter the metabolism of some drugs and xenobiotics. Gstz1(-/-) mice given acetaminophen demonstrated increased hepatotoxicity compared with wild-type mice. This toxicity may be attributed to the increased GST activity or the decreased hepatic concentrations of glutathione, or both. Patients with acquired deficiency of GSTZ1-1 caused by therapeutic exposure to dichloroacetic acid for the clinical treatment of lactic acidosis may be at increased risk of drug- and chemical-induced toxicity.
Collapse
Affiliation(s)
- Anneke C Blackburn
- Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, Canberra
| | | | | | | | | | | | | | | |
Collapse
|
95
|
Welch KD, Wen B, Goodlett DR, Yi EC, Lee H, Reilly TP, Nelson SD, Pohl LR. Proteomic identification of potential susceptibility factors in drug-induced liver disease. Chem Res Toxicol 2005; 18:924-33. [PMID: 15962927 DOI: 10.1021/tx050011b] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Drug-induced liver disease (DILD) causes significant morbidity and mortality and impairs new drug development. Currently, no known criteria can predict whether a drug will cause DILD or what risk factors make an individual susceptible. Although it has been shown in mouse studies that the disruption of key regulatory factors, such as cyclooxygenase-2 (COX-2), interleukin (IL)-6, and IL-10, increased susceptibility to DILD caused by acetaminophen (APAP), no single factor seems to be absolute. As an approach to better understand the multifactorial basis of DILD, we compared the hepatic proteome of mice that are resistant (SJL) and susceptible (C57Bl/6) to APAP-induced liver disease (AILD), using solution-based isotope-coded affinity tag (ICAT) liquid chromatography mass spectrometry. Several novel factors were identified that were more highly expressed in the livers of SJL mice, including those involved in stress response, cell proliferation and tissue regeneration, and protein modification, implicating these proteins as potential hepatoprotective factors. There was also a selective loss of several mitochondrial proteins from the livers of the susceptible C57Bl/6 mice, suggesting that the loss of functional mitochondria may indeed play a role in AILD. These findings indicate that comparative hepatic proteomic analyses of susceptible and resistant mouse strains may provide a global approach for identifying potential risk factors and mechanistic pathways responsible for DILD.
Collapse
Affiliation(s)
- Kevin D Welch
- Molecular and Cellular Toxicology Section, Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.
| | | | | | | | | | | | | | | |
Collapse
|
96
|
Dai G, Chou N, He L, Gyamfi MA, Mendy AJ, Slitt AL, Klaassen CD, Wan YJY. Retinoid X receptor alpha Regulates the expression of glutathione s-transferase genes and modulates acetaminophen-glutathione conjugation in mouse liver. Mol Pharmacol 2005; 68:1590-6. [PMID: 16157696 DOI: 10.1124/mol.105.013680] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nuclear receptors, including constitutive androstane receptor, pregnane X receptor, and retinoid X receptor (RXR), modulate acetaminophen (APAP)-induced hepatotoxicity by regulating the expression of phase I cytochrome P450 (P450) genes. It has not been fully resolved, however, whether they regulate APAP detoxification at the phase II level. The aim of the current study was to evaluate the role of RXRalpha in phase II enzyme-mediated detoxification of APAP. Wild-type and hepatocyte-specific RXRalpha knockout mice were treated with a toxic dose of APAP (500 mg/kg i.p.). Mutant mice were protected from APAP-induced hepatotoxicity, even though basal liver glutathione (GSH) levels were significantly lower in mutant mice compared with those of wild-type mice. High-performance liquid chromatography analysis of APAP metabolites revealed significantly greater levels of APAP-GSH conjugates in livers and bile of mutant mice compared with those of wild-type mice. Furthermore, hepatocyte RXRalpha deficiency altered the gene expression profile of the glutathione S-transferase (Gst) family. Basal expression of 13 of 15 Gst genes studied was altered in hepatocyte-specific RXRalpha-deficient mice. This probably led to enhanced APAP-GSH conjugation and reduced accumulation of N-acetyl-p-benzoquinone imine, a toxic electrophile that is produced by biotransformation of APAP by phase I P450 enzymes. In conclusion, the data presented in this study define an RXRalpha-Gst regulatory network that controls APAP-GSH conjugation. This report reveals a potential novel strategy to enhance the detoxification of APAP or other xenobiotics by manipulating Gst activity through RXRalpha-mediated pathways.
Collapse
Affiliation(s)
- Guoli Dai
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, Kansas 66160-7417, USA
| | | | | | | | | | | | | | | |
Collapse
|
97
|
Zhou S, Chan E, Duan W, Huang M, Chen YZ. Drug bioactivation, covalent binding to target proteins and toxicity relevance. Drug Metab Rev 2005; 37:41-213. [PMID: 15747500 DOI: 10.1081/dmr-200028812] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A number of therapeutic drugs with different structures and mechanisms of action have been reported to undergo metabolic activation by Phase I or Phase II drug-metabolizing enzymes. The bioactivation gives rise to reactive metabolites/intermediates, which readily confer covalent binding to various target proteins by nucleophilic substitution and/or Schiff's base mechanism. These drugs include analgesics (e.g., acetaminophen), antibacterial agents (e.g., sulfonamides and macrolide antibiotics), anticancer drugs (e.g., irinotecan), antiepileptic drugs (e.g., carbamazepine), anti-HIV agents (e.g., ritonavir), antipsychotics (e.g., clozapine), cardiovascular drugs (e.g., procainamide and hydralazine), immunosupressants (e.g., cyclosporine A), inhalational anesthetics (e.g., halothane), nonsteroidal anti-inflammatory drugs (NSAIDSs) (e.g., diclofenac), and steroids and their receptor modulators (e.g., estrogens and tamoxifen). Some herbal and dietary constituents are also bioactivated to reactive metabolites capable of binding covalently and inactivating cytochrome P450s (CYPs). A number of important target proteins of drugs have been identified by mass spectrometric techniques and proteomic approaches. The covalent binding and formation of drug-protein adducts are generally considered to be related to drug toxicity, and selective protein covalent binding by drug metabolites may lead to selective organ toxicity. However, the mechanisms involved in the protein adduct-induced toxicity are largely undefined, although it has been suggested that drug-protein adducts may cause toxicity either through impairing physiological functions of the modified proteins or through immune-mediated mechanisms. In addition, mechanism-based inhibition of CYPs may result in toxic drug-drug interactions. The clinical consequences of drug bioactivation and covalent binding to proteins are unpredictable, depending on many factors that are associated with the administered drugs and patients. Further studies using proteomic and genomic approaches with high throughput capacity are needed to identify the protein targets of reactive drug metabolites, and to elucidate the structure-activity relationships of drug's covalent binding to proteins and their clinical outcomes.
Collapse
Affiliation(s)
- Shufeng Zhou
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore.
| | | | | | | | | |
Collapse
|
98
|
Hinson JA, Reid AB, McCullough SS, James LP. Acetaminophen-induced hepatotoxicity: role of metabolic activation, reactive oxygen/nitrogen species, and mitochondrial permeability transition. Drug Metab Rev 2005; 36:805-22. [PMID: 15554248 DOI: 10.1081/dmr-200033494] [Citation(s) in RCA: 198] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Large doses of the analgesic acetaminophen cause centrilobular hepatic necrosis in man and in experimental animals. It has been previously shown that acetaminophen is metabolically activated by CYP enzymes to N-acetyl-p-benzoquinone imine. This species is normally detoxified by GSH, but following a toxic dose GSH is depleted and the metabolite covalently binds to a number of different proteins. Covalent binding occurs only to the cells developing necrosis. Recently we showed that these cells also contain nitrated tyrosine residues. Nitrotyrosine is mediated by peroxynitrite, a reactive nitrogen species formed by rapid reaction between nitric oxide and superoxide and is normally detoxified by GSH. Thus, acetaminophen toxicity occurs with increased oxygen/nitrogen stress. This manuscript will review current data on acetaminophen covalent binding, increased oxygen/nitrogen stress, and mitochondrial permeability transition, a toxic mechanism that is both mediated by and leads to increased oxygen/nitrogen stress.
Collapse
Affiliation(s)
- Jack A Hinson
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
| | | | | | | |
Collapse
|
99
|
Choi E, Lee S, Yeom SY, Kim GH, Lee JW, Kim SW. Characterization of activating signal cointegrator-2 as a novel transcriptional coactivator of the xenobiotic nuclear receptor constitutive androstane receptor. Mol Endocrinol 2005; 19:1711-9. [PMID: 15764585 DOI: 10.1210/me.2005-0066] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Activating signal cointegrator-2 (ASC-2) is a recently isolated transcriptional coactivator protein for a variety of different transcription factors, including many members of the nuclear receptor superfamily. In this report, we demonstrate that ASC-2 also serves as a coactivator of the xenobiotic nuclear receptor constitutive androstane receptor (CAR). First, transcriptional activation by CAR was enhanced by cotransfected ASC-2 in CV-1 and HeLa cells. In contrast, CAR transactivation was significantly impaired in HepG2 cells stably expressing specific small interfering RNA directed against ASC-2. Consistent with these results, chromatin immunoprecipitation experiments revealed that ASC-2 is recruited to the known CAR target genes in a ligand-dependent manner. Secondly, CAR specifically interacted with the first LXXLL motif of ASC-2, and these interactions were stimulated by CAR agonist 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene and repressed by CAR inverse agonist androstanol, suggesting that this motif may mediate the interactions of ASC-2 and CAR in vivo. In support of this idea, DN1, a fragment of ASC-2 encompassing the first LXXLL motif, suppressed CAR transactivation, and coexpressed ASC-2 but not other LXXLL-type coactivators such as thyroid hormone receptor-associated protein 220 reversed this repression. Finally, CAR was recently found to play a pivotal role in effecting the severe acetaminophen-induced liver damage. Interestingly, transgenic mice expressing DN1 were resistant to the acetaminophen-induced hepatotoxicity and expression of a series of the known CAR target genes was specifically repressed in these transgenic mice. Taken together, these results strongly suggest that ASC-2 is a bona fide coactivator of the xenobiotic nuclear receptor CAR and mediate the specific xenobiotic response by CAR in vivo.
Collapse
Affiliation(s)
- Eunho Choi
- Division Diabetes, Endocrinology & Metabolism, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | | | |
Collapse
|
100
|
Abstract
Glutathione transferases are a multi-gene family of enzymes responsible for the metabolism of a wide range of both endogenous and exogenous substrates. These polymorphic enzymes, which form part of an adaptive response to chemical and oxidative stress, are widely distributed and ubiquitously expressed and are subject to regulation by a number of structurally unrelated chemicals. One of these enzymes, GST P, has been the focus of much research in recent years in relation to its involvement in the etiology of disease, particularly cancer. As part of our research efforts into GST P, we have developed a mouse line that lacks this enzyme and have used this model to investigate the consequences of the absence of GST P on tumorigenesis, drug metabolism, and toxicity.
Collapse
Affiliation(s)
- Colin J Henderson
- Cancer Research UK, Molecular Pharmacology Unit, Biomedical Research Centre, Ninewells Hospital and Medical School, Dundee, United Kingdom
| | | |
Collapse
|