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Zhang Z, Zhang S, Zhang F, Zhang Q, Wei H, Xiu R, Zhao Y, Sui M. Clinical Indicators of Hepatotoxicity in Newly Diagnosed Acute Promyelocytic Leukemia Patients Undergoing Arsenic Trioxide Treatment. Biol Trace Elem Res 2024; 202:122-132. [PMID: 37097388 PMCID: PMC10764564 DOI: 10.1007/s12011-023-03676-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 04/18/2023] [Indexed: 04/26/2023]
Abstract
Arsenic trioxide (ATO)-induced hepatotoxicity is often observed in acute promyelocytic leukemia (APL) patients and decreases therapeutic effect of ATO. Thus, concerns over hepatotoxicity have been raised. The aim of this study was to explore some noninvasive clinical indicators that can be used to guide the individualized application of ATO in the future. APL patients treated with ATO were identified retrospectively via electronic health records at our hospital from August 2014 through August 2019. APL patients without hepatotoxicity were selected as controls. The association between putative risk factors and ATO-induced hepatotoxicity was estimated with ORs and 95% CIs, which were calculated using the chi-square test. The subsequent multivariate analysis was performed using logistic regression analysis. In total, 58.04% of patients experienced ATO-induced hepatotoxicity during the first week. Elevated hemoglobin (OR 8.653, 95% CI, 1.339-55.921), administration of nonprophylactic hepatoprotective agents (OR 36.455, 95% CI, 7.409-179.364), non-single-agent ATO to combat leukocytosis (OR 20.108, 95% CI, 1.357-297.893) and decreased fibrinogen (OR 3.496, 95% CI, 1.127-10.846) were found to be statistically significant risk factors for ATO-induced hepatotoxicity. The area under the ROC curve values were 0.846 for "overall ATO-induced hepatotoxicity" and 0.819 for "early ATO-induced hepatotoxicity." The results revealed that hemoglobin ≥ 80 g/L, nonprophylactic hepatoprotective agents, and non-single-agent ATO and fibrinogen < 1 g/L are risk factors for ATO-induced hepatotoxicity in newly diagnosed APL patients. These findings can enhance the clinical diagnosis of hepatotoxicity. Prospective studies should be performed in the future to validate these findings.
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Affiliation(s)
- Zhuo Zhang
- Central Laboratory, the First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Harbin, 150001, Heilongjiang, China
- Department of Hematology, Southern University of Science and Technology Hospital, Shenzhen, China
| | - Shunji Zhang
- Department of Hematology, the First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Fan Zhang
- Central Laboratory, the First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Harbin, 150001, Heilongjiang, China
| | - Qian Zhang
- Department of Hematology, the First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Hong Wei
- Department of Hematology, the First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Ruolin Xiu
- Department of Hematology, the First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yanhong Zhao
- Department of Hematology, the First Affiliated Hospital of Harbin Medical University, Harbin, China.
| | - Meijuan Sui
- Central Laboratory, the First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Harbin, 150001, Heilongjiang, China.
- Department of Hematology, the First Affiliated Hospital of Harbin Medical University, Harbin, China.
- Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
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Fujii J, Osaki T, Soma Y, Matsuda Y. Critical Roles of the Cysteine-Glutathione Axis in the Production of γ-Glutamyl Peptides in the Nervous System. Int J Mol Sci 2023; 24:ijms24098044. [PMID: 37175751 PMCID: PMC10179188 DOI: 10.3390/ijms24098044] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023] Open
Abstract
γ-Glutamyl moiety that is attached to the cysteine (Cys) residue in glutathione (GSH) protects it from peptidase-mediated degradation. The sulfhydryl group of the Cys residue represents most of the functions of GSH, which include electron donation to peroxidases, protection of reactive sulfhydryl in proteins via glutaredoxin, and glutathione conjugation of xenobiotics, whereas Cys-derived sulfur is also a pivotal component of some redox-responsive molecules. The amount of Cys that is available tends to restrict the capacity of GSH synthesis. In in vitro systems, cystine is the major form in the extracellular milieu, and a specific cystine transporter, xCT, is essential for survival in most lines of cells and in many primary cultivated cells as well. A reduction in the supply of Cys causes GPX4 to be inhibited due to insufficient GSH synthesis, which leads to iron-dependent necrotic cell death, ferroptosis. Cells generally cannot take up GSH without the removal of γ-glutamyl moiety by γ-glutamyl transferase (GGT) on the cell surface. Meanwhile, the Cys-GSH axis is essentially common to certain types of cells; primarily, neuronal cells that contain a unique metabolic system for intercellular communication concerning γ-glutamyl peptides. After a general description of metabolic processes concerning the Cys-GSH axis, we provide an overview and discuss the significance of GSH-related compounds in the nervous system.
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Affiliation(s)
- Junichi Fujii
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585, Japan
| | - Tsukasa Osaki
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585, Japan
| | - Yuya Soma
- Graduate School of Nursing, Yamagata University Faculty of Medicine, Yamagata 990-9585, Japan
| | - Yumi Matsuda
- Graduate School of Nursing, Yamagata University Faculty of Medicine, Yamagata 990-9585, Japan
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Khin Aung ZM, Jantaratnotai N, Piyachaturawat P, Sanvarinda P. A pure compound from Curcuma comosa Roxb. protects neurons against hydrogen peroxide-induced neurotoxicity via the activation of Nrf-2. Heliyon 2022; 8:e11228. [DOI: 10.1016/j.heliyon.2022.e11228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/12/2022] [Accepted: 10/20/2022] [Indexed: 10/31/2022] Open
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Epigenetic mechanisms underlying the toxic effects associated with arsenic exposure and the development of diabetes. Food Chem Toxicol 2017; 107:406-417. [PMID: 28709971 DOI: 10.1016/j.fct.2017.07.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/07/2017] [Accepted: 07/08/2017] [Indexed: 12/22/2022]
Abstract
BACKGROUND Exposure to inorganic arsenic (iAs) is a major threat to the human health worldwide. The consumption of arsenic in drinking water and other food products is associated with the risk of development of type-2 diabetes mellitus (T2DM). The available experimental evidence indicates that epigenetic alterations may play an important role in the development of diseases that are linked with exposure to environmental toxicants. iAs seems to be associated with the epigenetic modifications such as alterations in DNA methylation, histone modifications, and micro RNA (miRNA) abundance. OBJECTIVE This article reviewed epigenetic mechanisms underlying the toxic effects associated with arsenic exposure and the development of diabetes. METHOD Electronic databases such as PubMed, Scopus and Google scholar were searched for published literature from 1980 to 2017. Searched MESH terms were "Arsenic", "Epigenetic mechanism", "DNA methylation", "Histone modifications" and "Diabetes". RESULTS There are various factors involved in the pathogenesis of T2DM but it is assumed that arsenic consumption causes the epigenetic alterations both at the gene-specific level and generalized genome level. CONCLUSION The research indicates that exposure from low to moderate concentrations of iAs is linked with the epigenetic effects. In addition, it is evident that, arsenic can change the components of the epigenome and hence induces diabetes through epigenetic mechanisms, such as alterations in glucose transport and/or metabolism and insulin expression/secretion.
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Shintyapina AB, Vavilin VA, Safronova OG, Lyakhovich VV. The gene expression profile of a drug metabolism system and signal transduction pathways in the liver of mice treated with tert-butylhydroquinone or 3-(3'-tert-butyl-4'-hydroxyphenyl)propylthiosulfonate of sodium. PLoS One 2017; 12:e0176939. [PMID: 28467491 PMCID: PMC5415222 DOI: 10.1371/journal.pone.0176939] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 04/19/2017] [Indexed: 11/25/2022] Open
Abstract
Tert-butylhydroquinone (tBHQ) is a highly effective phenolic antioxidant used in edible oils and fats in foods as well as in medicines and cosmetics. TBHQ has been shown to have both chemoprotective and carcinogenic effects. Furthermore, it has potential anti-inflammatory, antiatherogenic, and neuroprotective activities. TBHQ induces phase II detoxification enzymes via the Keap1/Nrf2/ARE mechanism, which contributes to its chemopreventive functions. Nonetheless, there is growing evidence that biological effects of tBHQ may be mediated by Nrf2-independent mechanisms related to various signaling cascades. Here, we studied changes in gene expression of phase I, II, and III drug metabolizing enzymes/transporters as well as protein levels and activities of cytochromes P450 (CYPs) elicited by tBHQ and its structural homolog TS-13 in the mouse liver. Next, we carried out gene expression analysis to identify signal transduction pathways modulated by the antioxidants. Mice received 100 mg/kg tBHQ or TS-13 per day or only vehicle. The liver was collected at 12 hours and after 7 days of the treatment. Protein and total RNA were extracted. Gene expression was analyzed using Mouse Drug Metabolism and Signal Transduction PathwayFinder RT2Profiler™PCR Arrays. A western blot analysis was used to measure protein levels and a fluorometric assay was employed to study activities of CYPs. Genes that were affected more than 1.5-fold by tBHQ or TS-13 treatment compared with vehicle were identified. Analysis of the gene expression data revealed changes in various genes that are important for drug metabolism, cellular defense mechanisms, inflammation, apoptosis, and cell cycle regulation. Novel target genes were identified, including xenobiotic metabolism genes encoding CYPs, phase II/III drug metabolizing enzymes/transporters. For Cyp1a2 and Cyp2b, we observed an increase in protein levels and activities during tBHQ or TS-13 treatment. Changes were found in the gene expression regulated by NFκB, androgen, retinoic acid, PI3K/AKT, Wnt, Hedgehog and other pathways.
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Affiliation(s)
| | - Valentin A. Vavilin
- Institute of Molecular Biology and Biophysics, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | | | - Vyacheslav V. Lyakhovich
- Institute of Molecular Biology and Biophysics, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
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Duan X, Li J, Li W, Xing X, Zhang Y, Li W, Zhao L, Sun G, Gao XH, Li B. Antioxidant tert-butylhydroquinone ameliorates arsenic-induced intracellular damages and apoptosis through induction of Nrf2-dependent antioxidant responses as well as stabilization of anti-apoptotic factor Bcl-2 in human keratinocytes. Free Radic Biol Med 2016; 94:74-87. [PMID: 26878773 DOI: 10.1016/j.freeradbiomed.2016.02.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 01/28/2016] [Accepted: 02/10/2016] [Indexed: 01/27/2023]
Abstract
UNLABELLED Human skin is a known target site of inorganic arsenic with effects ranging from hyperkeratosis to dermal malignancies. Tert-butylhydroquinone (tBHQ), approved food-grade phenolic antioxidant, is demonstrated to induce remarkable antioxidant activity in a variety of cells and tissues. The present study aimed at the protective effects of tBHQ on arsenic-induced cytotoxicity and apoptosis in human keratinocytes. Our results demonstrated that tBHQ antagonized arsenic-induced decrease of cell viability, generation of reactive oxygen species (ROS) and lipid peroxidation, as well as reduction of antioxidative enzymes superoxide dismutase (SOD) and catalase (CAT) activities. We also found that tBHQ relieved the G2/M phase arrest by arsenic exposure, which was associated with altering the expression of cell cycle regulators cyclin D1 and CDK4. tBHQ treatment further reduced the numbers of arsenic-induced mitochondrial-mediated apoptotic cells, which occurred concomitantly with the effective recovery of mitochondrial membrane potential (ΔΨm) depolarization, the release of cytochrome c releasing from the mitochondrial as well as the survival signal related factor caspase 3 activation. Our experiments then confirmed that tBHQ activated nuclear factor E2-related factor 2 (NRF2) pathway by increasing NRF2 protein in both nucleus and cytoplasm and upregulating NRF2 downstream targets NAD(P)H quinine oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). More interestingly, arsenic-induced decrease of anti-apoptotic factor B-cell lymphoma-2 (Bcl-2) and increase of pro-apoptotic factor Bcl-2-associated X protein (Bax) could all be reversed by tBHQ pretreatment. These results suggested together that tBHQ could ameliorate arsenic-induced cytotoxicity and apoptosis, which might be linked with the induction of Nrf2-dependent antioxidant responses as well as stabilization of anti-apoptotic factor Bcl-2 in human keratinocytes.
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Affiliation(s)
- Xiaoxu Duan
- Department of Occupational and Environmental Health, Key Laboratory of Arsenic-related Biological Effects and Prevention and Treatment in Liaoning Province, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning Province 110013, China
| | - Jinlong Li
- Department of Occupational and Environmental Health, Key Laboratory of Arsenic-related Biological Effects and Prevention and Treatment in Liaoning Province, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning Province 110013, China
| | - Wei Li
- Health Care Department, Maternal and Child Health Care Center of Cangzhou, Cangzhou 061000, China
| | - Xiaoyue Xing
- Student Office, China Medical University, Shenyang 110013, China
| | - Yang Zhang
- Department of Occupational and Environmental Health, Key Laboratory of Arsenic-related Biological Effects and Prevention and Treatment in Liaoning Province, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning Province 110013, China
| | - Wei Li
- Department of Occupational and Environmental Health, Key Laboratory of Arsenic-related Biological Effects and Prevention and Treatment in Liaoning Province, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning Province 110013, China
| | - Lu Zhao
- Department of Occupational and Environmental Health, Key Laboratory of Arsenic-related Biological Effects and Prevention and Treatment in Liaoning Province, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning Province 110013, China
| | - Guifan Sun
- Environment and Non-Communicable Diseases Research Center, School of Public Health, China Medical University, Shenyang 110013, China
| | - Xing-Hua Gao
- Department of Dermatology, No. 1 Hospital of China Medical University, Shenyang 110001, China.
| | - Bing Li
- Department of Occupational and Environmental Health, Key Laboratory of Arsenic-related Biological Effects and Prevention and Treatment in Liaoning Province, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning Province 110013, China.
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Kang HJ, Oh Y, Lee S, Ryu IW, Kim K, Lim CJ. Antioxidative properties of ginsenoside Ro against UV-B-induced oxidative stress in human dermal fibroblasts. Biosci Biotechnol Biochem 2015. [DOI: 10.1080/09168451.2015.1065170] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Abstract
Ginsenoside Ro (Ro), an oleanolic acid-type ginsenoside, exhibited suppressive activities on reactive oxygen species (ROS) and matrix metalloproteinase-2 (MMP-2) elevation in UV-B-irradiated fibroblasts. Ro could overcome the reduction of the total glutathione (GSH) contents in UV-B-irradiated fibroblasts. Ro could not interfere with cell viabilities in UV-B-irradiated fibroblasts. Collectively, Ro possesses a potential skin anti-photoaging property against UV-B radiation in fibroblasts.
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Affiliation(s)
- Hyun Ji Kang
- Department of Biological Sciences, Kangwon National University, Chuncheon, Republic of Korea
| | - Yuri Oh
- Department of Biological Sciences, Kangwon National University, Chuncheon, Republic of Korea
| | - Sihyeong Lee
- Department of Biochemistry, Kangwon National University, Chuncheon, Republic of Korea
| | - In Wang Ryu
- Department of Biological Sciences, Kangwon National University, Chuncheon, Republic of Korea
| | - Kyunghoon Kim
- Department of Biological Sciences, Kangwon National University, Chuncheon, Republic of Korea
| | - Chang-Jin Lim
- Department of Biochemistry, Kangwon National University, Chuncheon, Republic of Korea
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Affiliation(s)
- Sarmishtha Chatterjee
- Environmental Toxicology
Laboratory, Department of Zoology, Centre for Advanced Studies, Visva-Bharati University, Santiniketan 731235, West Bengal, India
| | - Shuvasree Sarkar
- Environmental Toxicology
Laboratory, Department of Zoology, Centre for Advanced Studies, Visva-Bharati University, Santiniketan 731235, West Bengal, India
| | - Shelley Bhattacharya
- Environmental Toxicology
Laboratory, Department of Zoology, Centre for Advanced Studies, Visva-Bharati University, Santiniketan 731235, West Bengal, India
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Arsenic modulates posttranslational S-nitrosylation and translational proteome in keratinocytes. ScientificWorldJournal 2014; 2014:360153. [PMID: 25110733 PMCID: PMC4119667 DOI: 10.1155/2014/360153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 06/18/2014] [Indexed: 12/15/2022] Open
Abstract
Arsenic is a class I human carcinogen (such as inducing skin cancer) by its prominent chemical interaction with protein thio (-SH) group. Therefore, arsenic may compromise protein S-nitrosylation by competing the -SH binding activity. In the present study, we aimed to understand the influence of arsenic on protein S-nitrosylation and the following proteomic changes. By using primary human skin keratinocyte, we found that arsenic treatment decreased the level of protein S-nitrosylation. This was coincident to the decent expressions of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS). By using LC-MS/MS, around twenty S-nitrosoproteins were detected in the biotin-switched eluent. With the interest that arsenic not only regulates posttranslational S-nitrosylation but also separately affects protein's translation expression, we performed two-dimensional gel electrophoresis and found that 8 proteins were significantly decreased during arsenic treatment. Whether these decreased proteins are the consequence of protein S-nitrosylation will be further investigated. Taken together, these results provide a finding that arsenic can deplete the binding activity of NO and therefore reduce protein S-nitrosylation.
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Duan X, Liu D, Xing X, Li J, Zhao S, Nie H, Zhang Y, Sun G, Li B. Tert-butylhydroquinone as a phenolic activator of Nrf2 antagonizes arsenic-induced oxidative cytotoxicity but promotes arsenic methylation and detoxication in human hepatocyte cell line. Biol Trace Elem Res 2014; 160:294-302. [PMID: 24970285 DOI: 10.1007/s12011-014-0042-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 06/09/2014] [Indexed: 01/23/2023]
Abstract
Oxidative stress plays crucial roles in exerting a variety of damages upon arsenic exposure. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a master transcriptional regulator protecting cells and tissues from oxidative injuries. The objective of this study was to test whether tert-butylhydroquinone (tBHQ), a well-known synthetic Nrf2 inducer, could protect human hepatocytes against arsenic-induced cytotoxicity and oxidative injuries. Our results showed that 5 and 25 μmol/l tBHQ pretreatment suppressed the arsenic-induced hepatocellular cytotoxicity, reactive oxygen species generation, and hepatic lipid peroxidation, while relieved the arsenic-induced disturbances of intracellular glutathione balance. In addition, we also observed that tBHQ treatment promoted the arsenic biomethylation process and upregulated Nrf2-regulated downstream heme oxygenase-1 and NADPH: quinine oxidoreductase 1 mRNA expressions. Collectively, we suspected that Nrf2 signaling pathway may be involved in the protective effects of tBHQ against arsenic invasion in hepatocytes. These data suggest that phenolic Nrf2 inducers, such as tBHQ, represent novel therapeutic or dietary candidates for the population at high risk of arsenic poisoning.
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Affiliation(s)
- Xiaoxu Duan
- Department of Occupational and Environmental Health, Key Laboratory of Arsenic-Related Biological Effects and Prevention and Treatment in Liaoning Province, School of Public Health, China Medical University, 92 North 2nd Road, Heping District, Shenyang, 110001, China
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Sturchio E, Colombo T, Boccia P, Carucci N, Meconi C, Minoia C, Macino G. Arsenic exposure triggers a shift in microRNA expression. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 472:672-80. [PMID: 24317173 DOI: 10.1016/j.scitotenv.2013.11.092] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 11/07/2013] [Accepted: 11/18/2013] [Indexed: 05/24/2023]
Abstract
Exposure to inorganic Arsenic (iAs) through drinking water is a major public health problem affecting most countries. iAs has been classified by the International Agency for Research on Cancer as Group 1: "Carcinogenic to humans". Although numerous studies have shown the related adverse effects of iAs, sensitive appropriate biomarkers for studies of environmental epidemiology are still required. The present work aims at investigate the role of microRNAs (miRNAs), powerful negative regulators of gene expression, playing a key role in many physiological and pathological cellular processes, in iAs exposure. To this end, we analyzed miRNA changes in expression profile triggered by iAs exposure in Jurkat cell line. We used microarray technology to profile the expression of miRNAs following 2 μmol/L sodium arsenite treatment at different time points. Moreover, we performed phenotypic analysis of iAs treated cells. Real Time Polymerase Chain Reaction (RT-PCR) was used to validate miRNA microarray data and to assay expression modulation of selected relevant mRNAs. Finally, bioinformatics techniques were applied to reconstruct iAs-relevant molecular pathways and miRNA regulatory networks from the expression data. We report miRNAs modulated after iAs treatment in Jurkat cells. In particular, we highlight 36 miRNAs exhibiting consistent dysregulation and particularly a panel of 8 miRNAs which we also validated by RT-PCR analysis. Computational analysis of lists of putative target genes for these 8 miRNAs points to an involvement in arsenic-response pathways, for a subset of them, that were analyzed by RT-PCR. Furthermore, iAs exposure reveals induction of cell cycle progression and the failure of apoptosis, supporting the idea of iAs carcinogenic activity. Our study provides a list of miRNAs whose expression levels are affected by iAs treatment, corroborating the importance of proceeding with the hunt for specific subset of miRNAs, which can serve as potential biomarkers of iAs effects with useful diagnostic value.
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Affiliation(s)
- Elena Sturchio
- Italian Workers' Compensation Authority (INAIL), Department of Production Plants and Anthropic Settlements (DIPIA) Via Alessandria, 220/E, 00198 Rome, Italy.
| | - Teresa Colombo
- University of Rome "La Sapienza"-BCE, Viale del Policlinico 155, 00161, Rome, Italy
| | - Priscilla Boccia
- Italian Workers' Compensation Authority (INAIL), Department of Production Plants and Anthropic Settlements (DIPIA) Via Alessandria, 220/E, 00198 Rome, Italy
| | - Nicoletta Carucci
- University of Rome "La Sapienza"-BCE, Viale del Policlinico 155, 00161, Rome, Italy
| | - Claudia Meconi
- Italian Workers' Compensation Authority (INAIL), Department of Production Plants and Anthropic Settlements (DIPIA) Via Alessandria, 220/E, 00198 Rome, Italy
| | - Claudio Minoia
- Laboratory for Environmental and Toxicological Measurements, IRCCS Pavia, S. Maugeri Foundation, Via S. Maugeri, 8, 27100, Pavia, Italy
| | - Giuseppe Macino
- University of Rome "La Sapienza"-BCE, Viale del Policlinico 155, 00161, Rome, Italy
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Dowell JA, Johnson JA. Mechanisms of Nrf2 protection in astrocytes as identified by quantitative proteomics and siRNA screening. PLoS One 2013; 8:e70163. [PMID: 23922950 PMCID: PMC3726381 DOI: 10.1371/journal.pone.0070163] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 06/16/2013] [Indexed: 12/30/2022] Open
Abstract
The Nrf2 (NF-E2 related factor 2)-ARE (antioxidant response element) pathway controls a powerful array of endogenous cellular antioxidant systems and is an important pathway in the detoxification of reactive oxygen species (ROS) in the brain. Using a combination of quantitative proteomics and siRNA screening, we have identified novel protective mechanisms of the Nrf2-ARE pathway against oxidative stress in astrocytes. Studies from our lab and others have shown Nrf2 overexpression protects astrocytes from oxidative stress. However, the exact mechanisms by which Nrf2 elicits these effects are unknown. In this study, we show that induction of Nrf2 reduces levels of reactive oxygen species (ROS) produced by various oxidative stressors and results in robust cytoprotection. To identify the enzymes responsible for these effects, we used stable isotope labeling by amino acids in cell culture (SILAC) and quantitative shotgun proteomics to identify 72 Nrf2-regulated proteins in astrocytes. We hypothesized a subset of these proteins might play a critical role in Nrf2 protection. In order to identify these critical proteins, we used bioinformatics to narrow our target list of proteins and then systematically screened each candidate with siRNA to assess the role of each in Nrf2 protection. We screened each target against H2O2, tert-butyl hydroperoxide, and 4-hydroxynonenal and subsequently identified three enzymes-catalase, prostaglandin reductase-1, and peroxiredoxin-6-that are critical for Nrf2-mediated protection in astrocytes.
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Affiliation(s)
- James A. Dowell
- Division of Pharmaceutical Science, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jeffrey A. Johnson
- Division of Pharmaceutical Science, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Center of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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Effects of dietary tert-butylhydroquinone on domoic acid metabolism and transcription of detoxification-related liver genes in red sea bream Pagrus major. CHINESE SCIENCE BULLETIN-CHINESE 2013. [DOI: 10.1007/s11434-012-5643-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Huang CS, Lii CK, Lin AH, Yeh YW, Yao HT, Li CC, Wang TS, Chen HW. Protection by chrysin, apigenin, and luteolin against oxidative stress is mediated by the Nrf2-dependent up-regulation of heme oxygenase 1 and glutamate cysteine ligase in rat primary hepatocytes. Arch Toxicol 2012; 87:167-78. [DOI: 10.1007/s00204-012-0913-4] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 07/24/2012] [Indexed: 12/30/2022]
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Chen Y, Krishan M, Nebert DW, Shertzer HG. Glutathione-deficient mice are susceptible to TCDD-Induced hepatocellular toxicity but resistant to steatosis. Chem Res Toxicol 2011; 25:94-100. [PMID: 22082335 DOI: 10.1021/tx200242a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) generates both hepatocellular injury and steatosis, processes that involve oxidative stress. Herein, we evaluated the role of the antioxidant glutathione (GSH) in TCDD-induced hepatotoxicity. Glutamate-cysteine ligase (GCL), comprising catalytic (GCLC) and modifier (GCLM) subunits, is rate limiting in de novo GSH biosynthesis; GCLM maintains GSH homeostasis by optimizing the catalytic efficiency of GCL holoenzyme. Gclm(-/-) transgenic mice exhibit 10-20% of normal tissue GSH levels. Gclm(-/-) and Gclm(+/+) wild-type (WT) female mice received TCDD for 3 consecutive days and were then examined 21 days later. As compared with WT littermates, Gclm(-/-) mice were more sensitive to TCDD-induced hepatocellular toxicity, exhibiting lower reduction potentials for GSH, lower ATP levels, and elevated levels of plasma glutamic oxaloacetic transaminase (GOT) and γ-glutamyl transferase (GGT). However, the histopathology showed that TCDD-mediated steatosis, which occurs in WT mice, was absent in Gclm(-/-) mice. This finding was consistent with cDNA microarray expression analysis, revealing striking deficiencies in lipid biosynthesis pathways in Gclm(-/-) mice; qrt-PCR analysis confirmed that Gclm(-/-) mice are deficient in expression of several lipid metabolism genes including Srebp2, Elovl6, Fasn, Scd1/2, Ppargc1a, and Ppara. We suggest that whereas GSH protects against TCDD-mediated hepatocellular damage, GSH deficiency confers resistance to TCDD-induced steatosis due to impaired lipid metabolism.
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Affiliation(s)
- Ying Chen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver , Aurora, Colorado 80045, United States
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16
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Fujii J, Ito JI, Zhang X, Kurahashi T. Unveiling the roles of the glutathione redox system in vivo by analyzing genetically modified mice. J Clin Biochem Nutr 2011; 49:70-8. [PMID: 21980221 PMCID: PMC3171681 DOI: 10.3164/jcbn.10-138sr] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 12/31/2010] [Indexed: 12/19/2022] Open
Abstract
Redox status affects various cellular activities, such as proliferation, differentiation, and death. Recent studies suggest pivotal roles of reactive oxygen species not only in pathogenesis under oxidative insult but also in intracellular signal transduction. Glutathione is present in several millimolar concentrations in the cytoplasm and has multiple roles in the regulation of cellular homeostasis. Two enzymes, γ-glutamylcysteine synthetase and glutathione synthetase, constitute the de novo synthesis machinery, while glutathione reductase is involved in the recycling of oxidized glutathione. Multidrug resistant proteins and some other transporters are responsible for exporting oxidized glutathione, glutathione conjugates, and S-nitrosoglutathione. In addition to antioxidation, glutathione is more positively involved in cellular activity via its sulfhydryl moiety of a molecule. Animals in which genes responsible for glutathione metabolism are genetically modified can be used as beneficial and reliable models to elucidate roles of glutathione in vivo. This review article overviews recent progress in works related to genetically modified rodents and advances in the elucidation of glutathione-mediated reactions.
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Affiliation(s)
- Junichi Fujii
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
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17
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Koturbash I, Beland FA, Pogribny IP. Role of epigenetic events in chemical carcinogenesis—a justification for incorporating epigenetic evaluations in cancer risk assessment. Toxicol Mech Methods 2011; 21:289-97. [DOI: 10.3109/15376516.2011.557881] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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18
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Rossman TG, Klein CB. Genetic and epigenetic effects of environmental arsenicals. Metallomics 2011; 3:1135-41. [DOI: 10.1039/c1mt00074h] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Johansson E, Wesselkamper SC, Shertzer HG, Leikauf GD, Dalton TP, Chen Y. Glutathione deficient C57BL/6J mice are not sensitized to ozone-induced lung injury. Biochem Biophys Res Commun 2010; 396:407-12. [PMID: 20417186 DOI: 10.1016/j.bbrc.2010.04.105] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Accepted: 04/16/2010] [Indexed: 11/19/2022]
Abstract
In this study we examined the role of the antioxidant glutathione (GSH) in pulmonary susceptibility to ozone toxicity, utilizing GSH deficient C57BL/6J mice that lack the expression of glutamate-cysteine ligase modifier subunit (GCLM). Gclm(-/-) knockout mice had 70% GSH depletion in the lung. Gclm(+/+) wild-type and Gclm(-/-) mice were exposed to either 0.3 ppm ozone or filtered air for 48h. Ozone-induced lung hyperpermeability, as measured by total protein concentration in bronchoalveolar lavage fluid, was surprisingly lower in Gclm(-/-) mice than in wild-type mice. Lung hyperpermeability did not correlate with the degree of neutrophilia or with inflammatory gene expression. Pulmonary antioxidant response to ozone, assessed by increased mRNA levels of metallothionein 1 and 2, alpha-tocopherol transporter protein, and solute carrier family 23 member 2 (sodium-dependent vitamin C transporter) was greater in Gclm(-/-) mice than in Gclm(+/+) mice. These results suggest that compensatory augmentation of antioxidant defenses in Gclm(-/-) mice may confer increased resistance to ozone-induced lung injury.
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Affiliation(s)
- Elisabet Johansson
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, Cincinnati, OH 45267-0056, USA.
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20
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Calkins MJ, Vargas MR, Johnson DA, Johnson JA. Astrocyte-specific overexpression of Nrf2 protects striatal neurons from mitochondrial complex II inhibition. Toxicol Sci 2010; 115:557-68. [PMID: 20211941 DOI: 10.1093/toxsci/kfq072] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that is known to regulate a variety of cytoprotective genes through the antioxidant response element (ARE). This endogenous response is one of the major pathways by which cells are protected from xenobiotic or innate oxidative insults. Furthermore, in neural systems, astrocyte-specific activation of Nrf2 is known to protect neurons. In previous work, our laboratory found that Nrf2 protects from intrastriatal injections of the mitochondrial complex II inhibitor malonate. Here, we extend these results to show that multiple methods of astrocyte-specific Nrf2 overexpression provide protection from neurotoxicity in vivo. GFAP-Nrf2 transgenic mice are significantly more resistant to malonate lesioning. This outcome is associated with an increased basal resistance, but more so, an enhanced Nrf2 response to lesioning that attenuated the ensuing neurotoxicity. Furthermore, striatal transplantation of neuroprogenitor cells overexpressing Nrf2 that differentiate into astrocytes after grafting also significantly reduced malonate toxicity. Overall, these data establish that enhanced astrocytic Nrf2 response and Nrf2 preconditioning are both sufficient to protect from acute lesions from mitochondrial complex II inhibition.
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Affiliation(s)
- Marcus J Calkins
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, Wisconsin 53705, USA
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21
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Peng Z, Geh E, Chen L, Meng Q, Fan Y, Sartor M, Shertzer HG, Liu ZG, Puga A, Xia Y. Inhibitor of kappaB kinase beta regulates redox homeostasis by controlling the constitutive levels of glutathione. Mol Pharmacol 2010; 77:784-92. [PMID: 20159942 DOI: 10.1124/mol.109.061424] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytokine-activated inhibitor of kappaB kinase beta (IKKbeta) is a key mediator of immune and inflammatory responses, but recent studies suggest that IKKbeta is also required for tissue homeostasis in physiopathological processes. Here we report a novel role for IKKbeta in maintenance of constitutive levels of the redox scavenger GSH. Inactivation of IKKbeta by genetic or pharmacological means results in low cellular GSH content and marked reduction of redox potential. Similar to Ikkbeta(-/-) cells, Tnfr1(-/-) and p65(-/-) cells are also GSH-deficient. As a consequence, cells deficient in IKKbeta signaling are extremely susceptible to toxicity caused by environmental and pharmacological agents, including oxidants, genotoxic agents, microtubule toxins, and arsenic. GSH biosynthesis depends on the activity of the rate-limiting enzyme glutamate-cysteine ligase (GCL), consisting of a catalytic subunit (GCLC) and a modifier subunit (GCLM). We found that loss of IKKbeta signaling significantly reduces basal NF-kappaB activity and decreases binding of NF-kappaB to the promoters of Gclc and Gclm, leading to reduction of GCLC and GCLM expression. Conversely, overexpression of GCLC and GCLM in IKKbeta-null cells partially restores GSH content and prevents stress-induced cytotoxicity. We suggest that maintenance of GSH is a novel physiological role of the IKKbeta-NF-kappaB signaling cascade to prevent oxidative damage and preserve the functional integrity of the cells.
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Affiliation(s)
- Zhimin Peng
- Department of Environmental Health, University of Cincinnati Medical Center, Cincinnati, OH 45267-0056, USA
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22
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Abstract
Arsenic is a nonmutagenic human carcinogen that induces tumors through unknown mechanisms. A growing body of evidence suggests that its carcinogenicity results from epigenetic changes, particularly in DNA methylation. Changes in gene methylation status, mediated by arsenic, have been proposed to activate oncogene expression or silence tumor suppressor genes, leading to long-term changes in the activity of genes controlling cell transformation. Mostly descriptive, and often contradictory, studies have demonstrated that arsenic exposure is associated with both hypo- and hyper-methylation at various genetic loci in vivo or in vitro. This ambiguity has made it difficult to assess whether the changes induced by arsenic are causally involved in the transformation process or are simply a reflection of the altered physiology of rapidly dividing cancer cells. Here, we discuss the evidence supporting changes in DNA methylation as a cause of arsenic carcinogenesis and highlight the strengths and limitations of these studies, as well as areas where consistencies and inconsistencies exist.
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Affiliation(s)
- John F Reichard
- Department of Environmental Health & Center for Environmental Genetics, University of Cincinnati College of Medicine, 3223 Eden Avenue, Cincinnati, OH 45267-0056, USA.
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23
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Gruber F, Mayer H, Lengauer B, Mlitz V, Sanders JM, Kadl A, Bilban M, Martin R, Wagner O, Kensler TW, Yamamoto M, Leitinger N, Tschachler E. NF‐E2‐related factor 2 regulates the stress response to UVA‐1‐oxidized phospholipids in skin cells. FASEB J 2009; 24:39-48. [DOI: 10.1096/fj.09-133520] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Florian Gruber
- Department of DermatologyMedical University of ViennaViennaAustria
- Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Herbert Mayer
- Department of Vascular Biology and Thrombosis ResearchMedical University of ViennaViennaAustria
| | - Barbara Lengauer
- Department of DermatologyMedical University of ViennaViennaAustria
| | - Veronika Mlitz
- Department of DermatologyMedical University of ViennaViennaAustria
| | - John M. Sanders
- Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Alexandra Kadl
- Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Martin Bilban
- Department of Laboratory MedicineMedical University of ViennaViennaAustria
| | - Rainer Martin
- Department of Vascular Biology and Thrombosis ResearchMedical University of ViennaViennaAustria
| | - Oswald Wagner
- Department of Laboratory MedicineMedical University of ViennaViennaAustria
| | - Thomas W. Kensler
- Department of Environmental Health SciencesJohns Hopkins University Bloomberg School of Public HealthBaltimoreMarylandUSA
| | | | - Norbert Leitinger
- Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Erwin Tschachler
- Department of DermatologyMedical University of ViennaViennaAustria
- Centre de Recherches et d'Investigations Epidermiques et SensoriellesNeuillyFrance
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24
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Chen Y, Johansson E, Fan Y, Shertzer HG, Vasiliou V, Nebert DW, Dalton TP. Early onset senescence occurs when fibroblasts lack the glutamate-cysteine ligase modifier subunit. Free Radic Biol Med 2009; 47:410-8. [PMID: 19427898 PMCID: PMC2773044 DOI: 10.1016/j.freeradbiomed.2009.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 05/05/2009] [Accepted: 05/05/2009] [Indexed: 12/23/2022]
Abstract
Cellular senescence is the irreversible entry of cells into growth arrest. Senescence of primary cells in culture has long been used as an in vitro model for aging. Glutamate-cysteine ligase (GCL) controls the synthetic rate of the important cellular antioxidant glutathione (GSH). The catalytic subunit of GCL, GCLC, is catalytically active and essential for life. By contrast the modifier subunit of GCL, GCLM, is dispensable in mice. Although it is recognized that GCLM increases the rate of GSH synthesis, its physiological role is unclear. Herein, we show that loss of Gclm leads to premature senescence of primary murine fibroblasts as characterized by: (a) diminished growth rate, (b) cell morphology consistent with senescence, (c) increases in senescence-associated beta-galactosidase activity, and (d) cell cycle arrest at the G(1)/S and G(2)/M boundaries. These changes are accompanied by increased intracellular ROS, accumulation of DNA damage, and induction of p53 and p21 proteins. We also found that N-acetylcysteine increases intracellular GSH and prevents premature senescence in Gclm(-/-) cells. These results suggest that the control of GCLM, which in turn controls aspects of the cellular redox environment via GSH, is important in determining the replicative capacity of the cell.
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Affiliation(s)
- Ying Chen
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, Cincinnati, OH 45267-0056, USA.
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25
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Tartari S, D'Alessandro G, Babetto E, Rizzardini M, Conforti L, Cantoni L. Adaptation to G93Asuperoxide dismutase 1 in a motor neuron cell line model of amyotrophic lateral sclerosis: the role of glutathione. FEBS J 2009; 276:2861-74. [PMID: 19459941 DOI: 10.1111/j.1742-4658.2009.07010.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Motor neuron degeneration in amyotrophic lateral sclerosis involves oxidative damage. Glutathione (GSH) is critical as an antioxidant and a redox modulator. We used a motor neuronal cell line (NSC-34) to investigate whether wild-type and familial amyotrophic lateral sclerosis-linked G93A mutant Cu,Zn superoxide dismutase (wt/G93ASOD1) modified the GSH pool and glutamate cysteine ligase (GCL), the rate-limiting enzyme for GSH synthesis. We studied the effect of various G93ASOD1 levels and exposure times. Mutant Cu,Zn superoxide dismutase induced an adaptive process involving the upregulation of GSH synthesis, even at very low expression levels. However, cells with a high level of G93ASOD1 cultured for 10 weeks showed GSH depletion and a decrease in expression of the modulatory subunit of GCL. These cells also had lower levels of GSH and GCL activity was not induced after treatment with the pro-oxidant tert-butylhydroquinone. Cells with a low level of G93ASOD1 maintained higher GSH levels and GCL activity, showing that the exposure time and the level of the mutant protein modulate GSH synthesis. We conclude that failure of the regulation of the GSH pathway caused by G93ASOD1 may contribute to motor neuron vulnerability and we identify this pathway as a target for therapeutic intervention.
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Affiliation(s)
- Silvia Tartari
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
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26
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Jiang T, Huang Z, Chan JY, Zhang DD. Nrf2 protects against As(III)-induced damage in mouse liver and bladder. Toxicol Appl Pharmacol 2009; 240:8-14. [PMID: 19538980 DOI: 10.1016/j.taap.2009.06.010] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 06/08/2009] [Accepted: 06/10/2009] [Indexed: 02/07/2023]
Abstract
Arsenic compounds are classified as toxicants and human carcinogens. Environmental exposure to arsenic imposes a big health issue worldwide. Arsenic elicits its toxic efforts through many mechanisms, including generation of reactive oxygen species (ROS). Nrf2 is the primary transcription factor that controls expression of a main cellular antioxidant response, which is required for neutralizing ROS and thus defending cells from exogenous insults. Previously, we demonstrated a protective role of Nrf2 against arsenic-induced toxicity using a cell culture model. In this report, we present evidence that Nrf2 protects against liver and bladder injury in response to six weeks of arsenic exposure in a mouse model. Nrf2(-/-) mice displayed more severe pathological changes in the liver and bladder, compared to Nrf2(+/+) mice. Furthermore, Nrf2(-/-) mice were more sensitive to arsenic-induced DNA hypomethylation, oxidative DNA damage, and apoptotic cell death. These results indicate a protective role of Nrf2 against arsenic toxicity in vivo. Hence, this work demonstrates the feasibility of using dietary compounds that target activation of the Nrf2 signaling pathway to alleviate arsenic-induced damage.
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Affiliation(s)
- Tao Jiang
- Department of Pharmacology and Toxicology, University of Arizona, 1703 E. Mabel St., Tucson, AZ 85721, USA
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27
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Thompson JA, White CC, Cox DP, Chan JY, Kavanagh TJ, Fausto N, Franklin CC. Distinct Nrf1/2-independent mechanisms mediate As 3+-induced glutamate-cysteine ligase subunit gene expression in murine hepatocytes. Free Radic Biol Med 2009; 46:1614-25. [PMID: 19328227 PMCID: PMC2748780 DOI: 10.1016/j.freeradbiomed.2009.03.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 02/28/2009] [Accepted: 03/18/2009] [Indexed: 01/27/2023]
Abstract
Trivalent arsenite (As(3+)) is a known human carcinogen that is also capable of inducing apoptotic cell death. Increased production of reactive oxygen species is thought to contribute to both the carcinogenic and the cytotoxic effects of As(3+). Glutathione (GSH) constitutes a vital cellular defense mechanism against oxidative stress. The rate-limiting enzyme in GSH biosynthesis is glutamate-cysteine ligase (GCL), a heterodimeric holoenzyme composed of a catalytic (GCLC) and a modifier (GCLM) subunit. In this study, we demonstrate that As(3+) coordinately upregulates Gclc and Gclm mRNA levels in a murine hepatocyte cell line resulting in increased GCL subunit protein expression, holoenzyme formation, and activity. As(3+) increased the rate of transcription of both the Gclm and the Gclc genes and induced the posttranscriptional stabilization of Gclm mRNA. The antioxidant N-acetylcysteine abolished As(3+)-induced Gclc expression and attenuated induction of Gclm. As(3+) induction of Gclc and Gclm was also differentially regulated by the MAPK signaling pathways and occurred independent of the Nrf1/2 transcription factors. These findings demonstrate that distinct transcriptional and posttranscriptional mechanisms mediate the coordinate induction of the Gclc and Gclm subunits of GCL in response to As(3+) and highlight the potential importance of the GSH antioxidant defense system in regulating As(3+)-induced responses in hepatocytes.
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Affiliation(s)
- James A. Thompson
- Department of Pathology, University of Washington, Seattle, WA 98195
| | - Collin C. White
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195
| | - David P. Cox
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195
| | - Jefferson Y. Chan
- Department of Pathology and Laboratory Medicine, University of California-Irvine, Irvine, CA 92697
| | - Terrance J. Kavanagh
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195
| | - Nelson Fausto
- Department of Pathology, University of Washington, Seattle, WA 98195
| | - Christopher C. Franklin
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver, Aurora, CO 80045
- University of Colorado Cancer Center, University of Colorado Denver, Aurora, CO 80045
- To whom correspondence should be addressed: University of Colorado Denver, Department of Pharmaceutical Sciences, School of Pharmacy, C238-P15, Research-2, 12700 E. 19th Avenue, Room 3009, Aurora, CO 80045, phone: 303-724-6124, FAX: 303-724-7266, e-mail:
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28
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Muñiz Ortiz JG, Opoka R, Kane D, Cartwright IL. Investigating arsenic susceptibility from a genetic perspective in Drosophila reveals a key role for glutathione synthetase. Toxicol Sci 2009; 107:416-26. [PMID: 18779381 PMCID: PMC2639754 DOI: 10.1093/toxsci/kfn192] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 09/02/2008] [Indexed: 11/14/2022] Open
Abstract
Chronic exposure to arsenic-contaminated drinking water can lead to a variety of serious pathological outcomes. However, differential responsiveness within human populations suggests that interindividual genetic variation plays an important role. We are using Drosophila to study toxic metal response pathways because of unrivalled access to varied genetic approaches and significant demonstrable overlap with many aspects of mammalian physiology and disease phenotypes. Genetic analysis (via chromosomal segregation and microsatellite marker-based recombination) of various wild-type strains exhibiting relative susceptibility or tolerance to the lethal toxic effects of arsenite identified a limited X-chromosomal region (16D-F) able to confer a differential response phenotype. Using an FRT-based recombination approach, we created lines harboring small, overlapping deficiencies within this region and found that relative arsenite sensitivity arose when the dose of the glutathione synthetase (GS) gene (located at 16F1) was reduced by half. Knockdown of GS expression by RNA interference (RNAi) in cultured S2 cells led to enhanced arsenite sensitivity, while GS RNAi applied to intact organisms dramatically reduced the concentration of food-borne arsenite compatible with successful growth and development. Our analyses, initially guided by observations on naturally occurring variants, provide genetic proof that an optimally functioning two-step glutathione (GSH) biosynthetic pathway is required in vivo for a robust defense against arsenite; the enzymatic implications of this are discussed in the context of GSH supply and demand under arsenite-induced stress. Given an identical pathway for human GSH biosynthesis, we suggest that polymorphisms in GSH biosynthetic genes may be an important contributor to differential arsenic sensitivity and exposure risk in human populations.
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Affiliation(s)
| | | | | | - Iain L. Cartwright
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0524
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Effects of nickel, chromate, and arsenite on histone 3 lysine methylation. Toxicol Appl Pharmacol 2009; 236:78-84. [PMID: 19371620 DOI: 10.1016/j.taap.2009.01.009] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Revised: 01/12/2009] [Accepted: 01/14/2009] [Indexed: 01/28/2023]
Abstract
Occupational exposure to nickel (Ni), chromium (Cr), and arsenic (As) containing compounds has been associated with lung cancer and other adverse health effects. Their carcinogenic properties may be attributable in part, to activation and/or repression of gene expression induced by changes in the DNA methylation status and histone tail post-translational modifications. Here we show that individual treatment with nickel, chromate, and arsenite all affect the gene activating mark H3K4 methylation. We found that nickel (1 mM), chromate (10 microM), and arsenite (1 microM) significantly increase tri-methyl H3K4 after 24 h exposure in human lung carcinoma A549 cells. Seven days of exposure to lower levels of nickel (50 and 100 microM), chromate (0.5 and 1 microM) or arsenite (0.1, 0.5 and 1 microM) also increased tri-methylated H3K4 in A549 cells. This mark still remained elevated and inherited through cell division 7 days following removal of 1 microM arsenite. We also demonstrate by dual staining immunofluorescence microscopy that both H3K4 tri-methyl and H3K9 di-methyl marks increase globally after 24 h exposure to each metal treatment in A549 cells. However, the tri-methyl H3K4 and di-methyl H3K9 marks localize in different regions in the nucleus of the cell. Thus, our study provides further evidence that a mechanism(s) of carcinogenicity of nickel, chromate, and arsenite metal compounds may involve alterations of various histone tail modifications that may in turn affect the expression of genes that may cause transformation.
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30
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Abstract
Although carcinogenic metals have been known to disrupt a wide range of cellular processes the precise mechanism by which these exert their carcinogenic effects is not known. Over the last decade or two, studies in the field of metal carcinogenesis suggest that epigenetic mechanisms may play a role in metal-induced carcinogenesis. In this review we summarize the evidence demonstrating that exposure to carcinogenic metals such as nickel, arsenic, chromium, and cadmium can perturb DNA methylation levels as well as global and gene specific histone tail posttranslational modification marks. We also wish to emphasize the importance in understanding that gene expression can be regulated by both genetic and epigenetic mechanisms and both these must be considered when studying the mechanism underlying the toxicity and cell-transforming ability of carcinogenic metals and other toxicants, and aberrant changes in gene expression that occur during disease states such as cancer.
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Affiliation(s)
- Adriana Arita
- Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, NY 10987, USA
| | - Max Costa
- Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, NY 10987, USA
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31
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Ray A, Roy S, Agarwal S, Bhattacharya S. As2O3 toxicity in rat hepatocytes: manifestation of caspase-mediated apoptosis. Toxicol Ind Health 2008; 24:643-53. [DOI: 10.1177/0748233708100370] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In India, arsenic contamination in ground water is of immediate environmental concern affecting a large number of inhabitants in Kolkata. Arsenic is known to be one of the most toxic metalloids naturally occurring in the environment giving rise to severe toxic manifestations including cancer. Because arsenic is also used in chemotherapy of leukemia, it was considered worthwhile to concentrate on the mechanism of toxic action in normal hepatocytes which has not been addressed earlier. Rat hepatocytes were isolated and incubated in As2O3 at concentrations of 10, 20, and 40 μM in a time-dependent manner (0, 15, 30 min and 1, 2, and 4 h). The expression of the common stress proteins HSP 70 and 90 throughout the experimental duration confirmed the magnitude of toxic effect imposed by arsenic. Microscopic observations showed clear apoptotic changes in hepatocytes, which were further characterized by DNA ladder formation in time- and concentration-dependent manners. Apoptosis was triggered by caspase activation and over expression of bax at 10 μM As2O3 and at 20 and 40 μM concentrations of As2O3, MAP kinases were found to mediate the apoptotic pathway. Co-treatment of cells with arsenic and caspase inhibitor (Ac-DEVD-Cho) led to over expression of bcl-2, suppression of bax, and cytosolic sequestration of Bid and Bad. It is therefore concluded that caspase activation has a direct role in arsenic-induced apoptosis mediated by mitochondrial factors at 10 μM As2O3, and JUN N-terminal kinase (JNK) and P38 activation are the major mediators of apoptosis at the higher test concentrations (20 and 40 μM) of As2O3.
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Affiliation(s)
- A Ray
- Environmental Toxicology Laboratory, Department of Zoology, School of Life Science, Visva Bharati University, Santiniketan, India
| | - S Roy
- Ocean Research Institute, University of Tokyo, Japan
| | - S Agarwal
- Environmental Toxicology Laboratory, Department of Zoology, School of Life Science, Visva Bharati University, Santiniketan, India
| | - S Bhattacharya
- Environmental Toxicology Laboratory, Department of Zoology, School of Life Science, Visva Bharati University, Santiniketan, India
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Agarwal S, Roy S, Ray A, Mazumder S, Bhattacharya S. Arsenic trioxide and lead acetate induce apoptosis in adult rat hepatic stem cells. Cell Biol Toxicol 2008; 25:403-13. [PMID: 18618274 DOI: 10.1007/s10565-008-9094-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Accepted: 06/14/2008] [Indexed: 12/29/2022]
Abstract
In the present study, the toxicity of arsenic trioxide and lead acetate was assessed in adult hepatic stem cells induced in the 2-acetyl-aminofluorene/partial hepatectomy rat model. Isolated oval cells were incubated separately for 6 h with 40 muM each of arsenic trioxide and lead acetate. 3-(4,5-Dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay denoted significant time-dependent cell death in arsenic and lead treated oval cells. The degree of stress imposed by these metals was evidenced by induction of heat shock protein (HSP) 70 and HSP 90. Arsenic and lead were found to trigger apoptosis as revealed by DNA ladder formation, Western blots of apoptotic factors, and reverse transcriptase polymerase chain reaction analyses of bax and bcl-2. Results clearly indicate that both arsenic and lead induced apoptosis is caspase-mediated and accompanied by extracellular signal-regulated kinase (ERK) dephosphorylation. Full-length BH3-interacting-domain death agonist expression in presence of caspase 3 inhibitor unravels a direct involvement of caspase in As and Pb induced apoptosis. Expression patterns of apoptosis inducing factor, B cell lymphoma-2 (Bcl-2) antagonist of cell death, Bcl-2-associated X protein, and Bcl2 also signify mitochondrial regulation of apoptosis effected by lead and arsenic. It is concluded that stimulation of caspase cascade and simultaneous ERK dephosphorylation are the most significant operative pathways directly associated with apoptotic signals triggered by arsenic and lead in the oval cells.
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Affiliation(s)
- Soumik Agarwal
- Environmental Toxicology Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan 731235, India
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Reichard JF, Sartor MA, Puga A. BACH1 is a specific repressor of HMOX1 that is inactivated by arsenite. J Biol Chem 2008; 283:22363-70. [PMID: 18550526 DOI: 10.1074/jbc.m801784200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Intracellular heme is a redox active molecule that can be detrimental to cells at high concentrations or under oxidizing conditions. To prevent accumulation, the inducible enzyme heme oxygenase-1 (HMOX1) catalyzes degradation of heme. In the absence of elevated intracellular heme or oxidative stress, the basic region leucine zipper transcriptional regulator BACH1 binds HMOX1 antioxidant response elements and represses transcription. Conversely, increased intracellular heme or sulfhydryl oxidation inactivate BACH1, permitting transcriptional induction of HMOX1. Here, we investigate the effect of BACH1 inactivation on the induction of HMOX1 and as a mechanism for broader gene induction. We show that BACH1 is inactivated at low micromolar arsenite concentrations and that BACH1 inactivation is necessary and sufficient for transcriptional induction of HMOX1. Because BACH1 is thought to interact with antioxidant response element motifs, we further examined the role of BACH1 as a regulator of inducible antioxidant gene expression by assessing the global profile of gene expression following BACH1 knockdown using small interfering RNA. The loss of BACH1 function in human keratinocytes results almost exclusively in HMOX1 induction, suggesting that BACH1 may function as a rheostat regulating levels of intracellular free heme.
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Affiliation(s)
- John F Reichard
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati, Cincinnati, Ohio 45267, USA.
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Zhou X, Sun H, Ellen TP, Chen H, Costa M. Arsenite alters global histone H3 methylation. Carcinogenesis 2008; 29:1831-6. [PMID: 18321869 DOI: 10.1093/carcin/bgn063] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Arsenic (As) is a well-characterized human carcinogen but is generally not mutagenic. The evidence that As induces both loss of global DNA methylation and gene promoter DNA hypermethylation has suggested that epigenetic mechanisms may play an important role in As-induced carcinogenesis. In the present study, we examined the change in histone methylation by As exposure. In human lung carcinoma A549 cells, exposure to inorganic trivalent As (arsenite) increased H3K9 dimethylation (H3K9me2) and decreased H3K27 trimethylation (H3K27me3), both of which represent gene silencing marks, while increasing the global levels of the H3K4 trimethylation (H3K4me3), a gene-activating mark. The increase in H3K9me2 was mediated by an increase in the histone methyltransferase G9a protein and messenger RNA levels. We also observed strikingly significant altered histone modifications induced by very low-dose (0.1 microM) arsenite. Taken together, these results suggest a potential mechanism by which As induces carcinogenesis through the alteration of specific histone methylations that represent both gene silencing and activating marks. Furthermore, these marks are known to affect DNA methylation, and it is likely that arsenic's effect is not limited to histone modifications alone, but extends, perhaps by them, to DNA methylations as well. Future studies in our laboratory will address the genomic location of these silencing and activating marks using ChIP-on-chip technology.
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Affiliation(s)
- Xue Zhou
- Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987, USA
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35
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Ahlborn GJ, Nelson GM, Ward WO, Knapp G, Allen JW, Ouyang M, Roop BC, Chen Y, O'Brien T, Kitchin KT, Delker DA. Dose response evaluation of gene expression profiles in the skin of K6/ODC mice exposed to sodium arsenite. Toxicol Appl Pharmacol 2008; 227:400-16. [DOI: 10.1016/j.taap.2007.10.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 10/02/2007] [Accepted: 10/29/2007] [Indexed: 12/13/2022]
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Reichard JF, Motz GT, Puga A. Heme oxygenase-1 induction by NRF2 requires inactivation of the transcriptional repressor BACH1. Nucleic Acids Res 2007; 35:7074-86. [PMID: 17942419 PMCID: PMC2175339 DOI: 10.1093/nar/gkm638] [Citation(s) in RCA: 290] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Oxidative stress activates the transcription factor NRF2, which in turn binds cis-acting antioxidant response element (ARE) enhancers and induces expression of protective antioxidant genes. In contrast, the transcriptional repressor BACH1 binds ARE-like enhancers in cells naïve to oxidative stress and antagonizes NRF2 binding until it becomes inactivated by pro-oxidants. Here, we describe the dynamic roles of BACH1 and NRF2 in the transcription of the heme oxygenase-1 (HMOX1) gene. HMOX1 induction, elicited by arsenite-mediated oxidative stress, follows inactivation of BACH1 and precedes activation of NRF2. BACH1 repression is dominant over NRF2-mediated HMOX1 transcription and inactivation of BACH1 is a prerequisite for HMOX1 induction. In contrast, thioredoxin reductase 1 (TXNRD1) is regulated by NRF2 but not by BACH1. By comparing the expression levels of HMOX1 with TXNRD1, we show that nuclear accumulation of NRF2 is not necessary for HMOX1 induction; rather, BACH1 inactivation permits NRF2 already present in the nucleus at low basal levels to bind the HMOX1 promoter and elicit HMOX1 induction. Thus, BACH1 confers an additional level of regulation to ARE-dependent genes that reveals a new dimension to the oxidative stress response.
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Affiliation(s)
- John F Reichard
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati, Cincinnati, OH 45267-0056, USA.
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37
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Chang X, Fan Y, Karyala S, Schwemberger S, Tomlinson CR, Sartor MA, Puga A. Ligand-independent regulation of transforming growth factor beta1 expression and cell cycle progression by the aryl hydrocarbon receptor. Mol Cell Biol 2007; 27:6127-39. [PMID: 17606626 PMCID: PMC1952156 DOI: 10.1128/mcb.00323-07] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates the toxic effects of its xenobiotic ligands and acts as an environmental checkpoint during the cell cycle. We expressed stably integrated, Tet-Off-regulated AHR variants in fibroblasts from AHR-null mice to further investigate the AHR role in cell cycle regulation. Ahr+/+ fibroblasts proliferated significantly faster than Ahr-/- fibroblasts did, and exposure to a prototypical AHR ligand or deletion of the ligand-binding domain did not change their proliferation rates, indicating that the AHR function in cell cycle was ligand independent. Growth-promoting genes, such as cyclin and cyclin-dependent kinase genes, were significantly down-regulated in Ahr-/- cells, whereas growth-arresting genes, such as the transforming growth factor beta1 (TGF-beta1) gene, extracellular matrix (ECM)-related genes, and cyclin-dependent kinase inhibitor genes, were up-regulated. Ahr-/- fibroblasts secreted significantly more TGF-beta1 into the culture medium than Ahr+/+ fibroblasts did, and Ahr-/- showed increased levels of activated Smad4 and TGF-beta1 mRNA. Inhibition of TGF-beta1 signaling by overexpression of Smad7 reversed the proliferative and gene expression phenotype of Ahr-/- fibroblasts. Changes in TGF-beta1 mRNA accumulation were due to stabilization resulting from decreased activity of TTP, the tristetraprolin RNA-binding protein responsible for mRNA destabilization through AU-rich motifs. These results show that the Ah receptor possesses interconnected intrinsic cellular functions, such as ECM formation, cell cycle control, and TGF-beta1 regulation, that are independent of activation by either exogenous or endogenous ligands and that may play a crucial role during tumorigenesis.
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Affiliation(s)
- Xiaoqing Chang
- Department of Environmental Health, University of Cincinnati Medical Center, and Shriners Hospital for Children, Cincinnati, OH 45267-0056, USA
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Peng Z, Peng L, Fan Y, Zandi E, Shertzer HG, Xia Y. A critical role for IkappaB kinase beta in metallothionein-1 expression and protection against arsenic toxicity. J Biol Chem 2007; 282:21487-96. [PMID: 17526490 DOI: 10.1074/jbc.m702510200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Arsenic is a widespread environmental toxic agent that has been shown to cause diverse tissue and cell damage and at the same time to be an effective anti-cancer therapeutic agent. The objective of this study is to explore the signaling mechanisms involved in arsenic toxicity. We show that the IkappaB kinase beta (IKKbeta) plays a crucial role in protecting cells from arsenic toxicity. Ikkbeta(-)(/)(-) mouse 3T3 fibroblasts have decreased expression of antioxidant genes, such as metallothionein 1 (Mt1). In contrast to wild type and IKKbeta-reconstituted Ikkbeta(-)(/)(-) cells, IKKbeta-null cells display a marked increase in arsenic-induced reactive oxygen species (ROS) accumulation, which leads to activation of the MKK4-c-Jun NH(2)-terminal kinase (JNK) pathway, c-Jun phosphorylation, and apoptosis. Pretreatment with the antioxidant N-acetylcysteine (NAC) and expression of MT1 in the Ikkbeta(-)(/)(-) cells prevented JNK activation; moreover, NAC pretreatment, MT1 expression, MKK4 ablation, and JNK inhibition all protected cells from death induced by arsenic. Our data show that two signaling pathways appear to be important for modulating arsenic toxicity. First, the IKK-NF-kappaB pathway is crucial for maintaining cellular metallothionein-1 levels to counteract ROS accumulation, and second, when this pathway fails, excessive ROS leads to activation of the MKK4-JNK pathway, resulting in apoptosis.
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Affiliation(s)
- Zhimin Peng
- Department of Environmental Health, University of Cincinnati Medical Center, Cincinnati, Ohio 45267-0056, USA
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39
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Regulating effects of arsenic trioxide on cell death pathways and inflammatory reactions of pancreatic acinar cells in rats. Chin Med J (Engl) 2007. [DOI: 10.1097/00029330-200704020-00015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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40
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Habib GM, Shi ZZ, Lieberman MW. Glutathione protects cells against arsenite-induced toxicity. Free Radic Biol Med 2007; 42:191-201. [PMID: 17189825 PMCID: PMC1855165 DOI: 10.1016/j.freeradbiomed.2006.10.036] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 10/05/2006] [Accepted: 10/07/2006] [Indexed: 02/07/2023]
Abstract
To understand the role of glutathione (GSH) in the protection of cells from arsenite toxicity, we studied the mechanism of apoptotic cell death in cells genetically unable to synthesize GSH (GCS-2 cells). Arsenite stimulated an increase in protein ubiquitination in GCS-2 cells while the wild-type cells were unaffected. Arsenite treatment increased lipid peroxidation and induced ubiquitination of molecular chaperone Hsp90 and impaired its ability to bind cochaperone p50(Cdc-37) and client proteins Plk-1 and Cdk-4 in GCS-2 cells. Treatment with arsenite also partially inhibited proteasome activity in GCS-2 cells. In these cells stably transfected with GFP(u) (a reporter consisting of a short degron fused to the COOH-terminus of GFP), intracellular fluorescence increased, suggesting the accumulation of GFP aggregates. GCS-2 cells underwent apoptosis accompanied by release of cytochrome c into the cytoplasm. Taken together, these data suggest that a possible mechanism of arsenite-induced apoptosis is the accumulation of ubiquitinated proteins and impairment of the protein degradative pathway. Further, protection from arsenite-induced ubiquitination is mediated by GSH and to a lesser extent by available reducing equivalents in the cells.
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Affiliation(s)
- Geetha M Habib
- Department of Pathology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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41
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Yu ZY, Liang YG, Xiao H, Shan YJ, Dong B, Huang R, Fu YL, Zhao ZH, Liu ZY, Zhao QS, Wang SQ, Chen JP, Mao BZ, Cong YW. Melissoidesin G, a diterpenoid purified fromIsodon melissoides, induces leukemic-cell apoptosis through induction of redox imbalance and exhibits synergy with other anticancer agents. Int J Cancer 2007; 121:2084-2094. [PMID: 17640057 DOI: 10.1002/ijc.22945] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Melissoidesin G (MOG) is a new diterpenoid purified from Isodon melissoides, a plant used in Chinese traditional medicine as antitumor and anti-inflammatory agents. In our study, MOG was shown to specifically inhibit the growth of human leukemia cell lines and primary acute myeloid leukemia (AML) blasts via induction of apoptosis, with the evidence of mitochondrial DeltaPsim loss, reactive oxygen species production, caspases activation and nuclear fragmentation. Furthermore, it was shown that thiol-containing antioxidants completely blocked MOG-induced mitochondrial DeltaPsim loss and subsequent cell apoptosis, while the inhibition of apoptosis by benzyloxy-carbonyl-Val-Ala-Asp-fluoromethylketone only partially attenuated mitochondrial DeltaPsim loss, indicating that MOG-induced redox imbalance is an early event upstream to mitochondrial DeltaPsim loss and caspase-3 activation. Consistently, it was found that MOG rapidly decreased the intracellular glutathione (GSH) content in a dose-dependent manner and the significance of GSH depletion in MOG-induced apoptosis was further supported by the protective effects of tert-butylhydroquinone (tBHQ) and the facilitative effects of DL-buthionine (S,R)-sulfoximine (BSO). Furthermore, it was showed that GSH depletion induced by MOG rendered some leukemia cell lines more sensitive to arsenic trioxide (As2O3), doxorubicin or cisplatin. Additionally, the synergistic apoptotic effects of MOG with As2O3 were detected in HL-60 and primary AML cells, but not in normal cells, suggesting the selective toxicity of their combination to the malignant cells. Together, we proposed that MOG alone or administered with other anticancer agents may provide a novel therapeutic strategy for leukemia.
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Affiliation(s)
- Zu-Yin Yu
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Yu-Guang Liang
- Department of Clinical Pharmacology, Beijing 307 Hospital, Academy of Medical Sciences, Beijing, China
| | - He Xiao
- Department of Molecular Immunology, Institute of Basic Medical Sciences, Beijing, China
| | - Ya-Jun Shan
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Bo Dong
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Rui Huang
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Ya-Li Fu
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Zhen-Hu Zhao
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Ze-Yuan Liu
- Department of Clinical Pharmacology, Beijing 307 Hospital, Academy of Medical Sciences, Beijing, China
| | - Qin-Shi Zhao
- Department of Phytochemisty, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Sheng-Qi Wang
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Jia-Pei Chen
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Bing-Zhi Mao
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Yu-Wen Cong
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, Beijing, China
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Reichard JF, Schnekenburger M, Puga A. Long term low-dose arsenic exposure induces loss of DNA methylation. Biochem Biophys Res Commun 2006; 352:188-92. [PMID: 17107663 PMCID: PMC1866367 DOI: 10.1016/j.bbrc.2006.11.001] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Accepted: 11/01/2006] [Indexed: 12/22/2022]
Abstract
Arsenic ranks as the number one toxic environmental contaminant. In humans, arsenic exposure is associated with various forms of cancer, cardiovascular and skin diseases, neuropathies of the central nervous system, and genotoxic and immunotoxic effects. Although a well recognized human carcinogen, arsenic itself is not a potent mutagen and has been thought to act through epigenetic mechanisms that modify DNA methylation patterns, perhaps in conjunction with DNA-damaging agents. To develop preliminary support for a more thorough examination of this hypothesis, we have measured the effect of submicromolar and low-micromolar concentrations of arsenite on the methylation status of DNA and the biochemical reactions that regulate it. We find that arsenic causes the depletion of S-adenosylmethionine, the main cellular methyl donor, and represses the expression of the DNA methyltransferase genes DNMT1 and DNMT3A. Possibly as a consequence of these two complementary mechanisms, long-term exposure to arsenic results in DNA hypomethylation.
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Affiliation(s)
| | | | - Alvaro Puga
- Corresponding author: Alvaro Puga, Department of Environmental Health, University of Cincinnati Medical Center P.O. Box 670056. Cincinnati, OH 45367-00567 (Messenger Mail, use: 123 E. Shields St. Cincinnati, OH 45220), Phone: (513) 558-0916, FAX: (513) 558-0925, E-mail:
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Hays AM, Srinivasan D, Witten ML, Carter DE, Lantz RC. Arsenic and cigarette smoke synergistically increase DNA oxidation in the lung. Toxicol Pathol 2006; 34:396-404. [PMID: 16844668 DOI: 10.1080/01926230600824926] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Epidemiological evidence has indicated that arsenic and cigarette smoking exposure act synergistically to increase the incidence of lung cancer. Since oxidative damage of DNA has been linked to cancer, our hypothesis is that aerosolized arsenic and cigarette smoke work synergistically to increase oxidative stress and increase DNA oxidation in the lung. To test this hypothesis male Syrian golden hamsters were exposed to room air (control), aerosolized arsenic compounds (3.2 mg/m3 for 30 minutes), cigarette smoke (5 mg/m3 for 30 minutes), or both smoke and arsenic. Exposures were for 5 days/week for 5 or 28-days. Animals were sacrificed one day after the last exposure. In the 28-day group, glutathione levels and DNA oxidation (8-oxo-2'-deoxyguanosine (8-oxo-dG)) were determined. Our results show that in the 28-day arsenic/smoke group there was a significant decrease in both the reduced and total glutathione levels compared with arsenic or smoke alone. This correlated with a 5-fold increase in DNA oxidation as shown by HPLC. Immunohistochemical localization of 8-oxo-dG showed increase staining in nuclei of airway epithelium and subadjacent interstitial cells. These results show that dual exposure of arsenic and cigarette smoke at environmentally relevant levels can act synergistically to cause DNA damage.
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Affiliation(s)
- Allison Marie Hays
- Department of Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85724-5044, USA
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