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Ajsuvakova OP, Tinkov AA, Aschner M, Rocha JB, Michalke B, Skalnaya MG, Skalny AV, Butnariu M, Dadar M, Sarac I, Aaseth J, Bjørklund G. Sulfhydryl groups as targets of mercury toxicity. Coord Chem Rev 2020; 417:213343. [PMID: 32905350 PMCID: PMC7470069 DOI: 10.1016/j.ccr.2020.213343] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The present study addresses existing data on the affinity and conjugation of sulfhydryl (thiol; -SH) groups of low- and high-molecular-weight biological ligands with mercury (Hg). The consequences of these interactions with special emphasis on pathways of Hg toxicity are highlighted. Cysteine (Cys) is considered the primary target of Hg, and link its sensitivity with thiol groups and cellular damage. In vivo, Hg complexes play a key role in Hg metabolism. Due to the increased affinity of Hg to SH groups in Cys residues, glutathione (GSH) is reactive. The geometry of Hg(II) glutathionates is less understood than that with Cys. Both Cys and GSH Hg-conjugates are important in Hg transport. The binding of Hg to Cys mediates multiple toxic effects of Hg, especially inhibitory effects on enzymes and other proteins that contain free Cys residues. In blood plasma, albumin is the main Hg-binding (Hg2+, CH3Hg+, C2H5Hg+, C6H5Hg+) protein. At the Cys34 residue, Hg2+ binds to albumin, whereas other metals likely are bound at the N-terminal site and multi-metal binding sites. In addition to albumin, Hg binds to multiple Cys-containing enzymes (including manganese-superoxide dismutase (Mn-SOD), arginase I, sorbitol dehydrogenase, and δ-aminolevulinate dehydratase, etc.) involved in multiple processes. The affinity of Hg for thiol groups may also underlie the pathways of Hg toxicity. In particular, Hg-SH may contribute to apoptosis modulation by interfering with Akt/CREB, Keap1/Nrf2, NF-κB, and mitochondrial pathways. Mercury-induced oxidative stress may ensue from Cys-Hg binding and inhibition of Mn-SOD (Cys196), thioredoxin reductase (TrxR) (Cys497) activity, as well as limiting GSH (GS-HgCH3) and Trx (Cys32, 35, 62, 65, 73) availability. Moreover, Hg-thiol interaction also is crucial in the neurotoxicity of Hg by modulating the cytoskeleton and neuronal receptors, to name a few. However, existing data on the role of Hg-SH binding in the Hg toxicity remains poorly defined. Therefore, more research is needed to understand better the role of Hg-thiol binding in the molecular pathways of Hg toxicology and the critical role of thiols to counteract negative effects of Hg overload.
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Affiliation(s)
- Olga P. Ajsuvakova
- Yaroslavl State University, Yaroslavl, Russia
- Federal Scientific Center of Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Orenburg, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Alexey A. Tinkov
- Yaroslavl State University, Yaroslavl, Russia
- Federal Scientific Center of Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Orenburg, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Michael Aschner
- IM Sechenov First Moscow State Medical University, Moscow, Russia
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - João B.T. Rocha
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | | | | | - Anatoly V. Skalny
- Yaroslavl State University, Yaroslavl, Russia
- Federal Scientific Center of Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Orenburg, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Monica Butnariu
- Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
- CONEM Romania Biotechnology and Environmental Sciences Group, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Ioan Sarac
- Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
- CONEM Romania Biotechnology and Environmental Sciences Group, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
| | - Jan Aaseth
- IM Sechenov First Moscow State Medical University, Moscow, Russia
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine (CONEM), Mo i Rana, Norway
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Yang L, Zhang Y, Wang F, Luo Z, Guo S, Strähle U. Toxicity of mercury: Molecular evidence. CHEMOSPHERE 2020; 245:125586. [PMID: 31881386 DOI: 10.1016/j.chemosphere.2019.125586] [Citation(s) in RCA: 173] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/28/2019] [Accepted: 12/08/2019] [Indexed: 05/25/2023]
Abstract
Minamata disease in Japan and the large-scale poisoning by methylmercury (MeHg) in Iraq caused wide public concerns about the risk emanating from mercury for human health. Nowadays, it is widely known that all forms of mercury induce toxic effects in mammals, and increasing evidence supports the concern that environmentally relevant levels of MeHg could impact normal biological functions in wildlife. The information of mechanism involved in mercurial toxicity is growing but knowledge gaps still exist between the adverse effects and mechanisms of action, especially at the molecular level. A body of data obtained from experimental studies on mechanisms of mercurial toxicity in vivo and in vitro points to that disruption of the antioxidant system may play an important role in the mercurial toxic effects. Moreover, the accumulating evidence indicates that signaling transduction, protein or/and enzyme activity, and gene regulation are involving in mediating toxic and adaptive response to mercury exposure. We conducted here a comprehensive review of mercurial toxic effects on wildlife and human, in particular synthesized key findings of molecular pathways involved in mercurial toxicity from the cells to human. We discuss the molecular evidence related mercurial toxicity to the adverse effects, with particular emphasis on the gene regulation. The further studies relying on Omic analysis connected to adverse effects and modes of action of mercury will aid in the evaluation and validation of causative relationship between health outcomes and gene expression.
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Affiliation(s)
- Lixin Yang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China; Center for Global Health, School of Public Health, Nanjing Medical University, 211166, Nanjing, China.
| | - Yuanyuan Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Feifei Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Zidie Luo
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Shaojuan Guo
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Uwe Strähle
- Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
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3
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Chang Y, Lee WY, Lin YJ, Hsu T. Mercury (II) impairs nucleotide excision repair (NER) in zebrafish (Danio rerio) embryos by targeting primarily at the stage of DNA incision. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 192:97-104. [PMID: 28942072 DOI: 10.1016/j.aquatox.2017.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/30/2017] [Accepted: 09/02/2017] [Indexed: 05/20/2023]
Abstract
Mercuric ion (Hg2+) is the most prevalent form of inorganic Hg found in polluted aquatic environment. As inhibition of DNA damage repair has been proposed as one of the mechanisms of Hg2+-induced genotoxicity in aquatic animals and mammalian cells, this study explored the susceptibility of different stages of nucleotide excision repair (NER) in zebrafish (Danio rerio) embryos to Hg2+ using UV-damaged DNA as the repair substrate. Exposure of embryos at 1h post fertilization (hpf) to HgCl2 at 0.1-2.5μM for 9h caused a concentration-dependent inhibition of NER capacity monitored by a transcription-based DNA repair assay. The extracts of embryos exposed to 2.5μM Hg2+ almost failed to up-regulate UV-suppressed marker cDNA transcription. No inhibition of ATP production was observed in all Hg2+-exposed embryos. Hg2+ exposure imposed either weak inhibitory or stimulating effects on the gene expression of NER factors, while band shift assay showed the inhibition of photolesion binding activities to about 40% of control in embryos treated with 1-2.5μM HgCl2. The damage incision stage of NER in zebrafish embryos was found to be more sensitive to Hg2+ than photolesion binding capacity due to the complete loss of damage incision activity in the extracts of embryos exposed to 1-2.5μM Hg2+. NER-related DNA incision was induced in UV-irradiated embryos based on the production of short DNA fragments matching the sizes of excision products generated by eukaryotic NER. Pre-exposure of embryos to Hg2+ at 0.1-2.5μM all suppressed DNA incision/excision in UV-irradiated embryos, reflecting a high sensitivity of DNA damage incision/excision to Hg2+. Our results showed the potential of Hg2+ at environmental relevant levels to disturb NER in zebrafish embryos by targeting primarily at the stage of DNA incision/excision.
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Affiliation(s)
- Yung Chang
- Institute of Bioscience and Biotechnology and Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, 20224, Taiwan, Republic of China
| | - Wei-Yuan Lee
- Institute of Bioscience and Biotechnology and Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, 20224, Taiwan, Republic of China
| | - Yu-Jie Lin
- Institute of Bioscience and Biotechnology and Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, 20224, Taiwan, Republic of China
| | - Todd Hsu
- Institute of Bioscience and Biotechnology and Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, 20224, Taiwan, Republic of China.
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4
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Boatti L, Rapallo F, Viarengo A, Marsano F. Toxic effects of mercury on the cell nucleus of Dictyostelium discoideum. ENVIRONMENTAL TOXICOLOGY 2017; 32:417-425. [PMID: 26888062 DOI: 10.1002/tox.22245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 01/15/2016] [Accepted: 01/24/2016] [Indexed: 06/05/2023]
Abstract
Governmental agencies (www.epa.gov/mercury) and the scientific community have reported on the high toxicity due to mercury. Indeed, exposure to mercury can cause severe injury to the central nervous system and kidney in humans. Beyond its recognized toxicity, little is known regarding the molecular mechanisms involved in the actions of this heavy metal. Mercury has been also observed to form insoluble fibrous protein aggregates in the cell nucleus. We used D. discoideum to evaluate micronuclei formation and, since mercury is able to induce oxidative stress that could bring to protein aggregation, we assessed nuclear protein carbonylation by Western Blot. We observed a significant increase in micronuclei formation and 14 carbonylated proteins were identified. Moreover, we used isotope-coded protein label (ICPL) and mass spectrometry analysis of proteins obtained by lysis of purified nuclei, before of tryptic digestion to quantify nuclear proteins affected by mercury. In particular, we examined the effects of mercury that associate a classical genotoxic assay to proteomic effects into the nucleus. The data present direct evidences for mercury genotoxicity, nuclear protein carbonylation, quantitative change in core histones, and the involvement of pseudouridine synthase in mercury toxicity. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 417-425, 2017.
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Affiliation(s)
- Lara Boatti
- Department of Science and Technological Innovation (DiSIT), Università Del Piemonte Orientale "Amedeo Avogadro", Viale Teresa Michel, Alessandria, 11-15121, Italy
| | - Fabio Rapallo
- Department of Science and Technological Innovation (DiSIT), Università Del Piemonte Orientale "Amedeo Avogadro", Viale Teresa Michel, Alessandria, 11-15121, Italy
| | - Aldo Viarengo
- Department of Science and Technological Innovation (DiSIT), Università Del Piemonte Orientale "Amedeo Avogadro", Viale Teresa Michel, Alessandria, 11-15121, Italy
| | - Francesco Marsano
- Department of Science and Technological Innovation (DiSIT), Università Del Piemonte Orientale "Amedeo Avogadro", Viale Teresa Michel, Alessandria, 11-15121, Italy
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5
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Carneiro MFH, Morais C, Small DM, Vesey DA, Barbosa F, Gobe GC. Thimerosal induces apoptotic and fibrotic changes to kidney epithelial cells in vitro. ENVIRONMENTAL TOXICOLOGY 2015; 30:1423-1433. [PMID: 24942245 DOI: 10.1002/tox.22012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 05/28/2014] [Indexed: 06/03/2023]
Abstract
Thimerosal is an ethyl mercury-containing compound used mainly in vaccines as a bactericide. Although the kidney is a key target for mercury toxicity, thimerosal nephrotoxicity has not received the same attention as other mercury species. The aim of this study was to determine the potential cytotoxic mechanisms of thimerosal on human kidney cells. Human kidney proximal tubular epithelial (HK2) cells were exposed for 24 h to thimerosal (0-2 µM), and assessed for cell viability, apoptosis, and cell proliferation; expression of proteins Bax, nuclear factor-κB subunits, and transforming growth factor-β1 (TGFβ1); mitochondrial health (JC-1, MitoTracker Red CMXRos); and fibronectin levels (enzyme-linked immunosorbent assay). Thimerosal diminished HK2 cell viability and mitosis, promoted apoptosis, impaired the mitochondrial permeability transition, enhanced Bax and TGFβ1 expression, and augmented fibronectin secretion. This is the first report about kidney cell death and pro-fibrotic mechanisms promoted by thimerosal. Collectively, these in vitro results demonstrate that (1) thimerosal induces kidney epithelial cell apoptosis via upregulating Bax and the mitochondrial apoptotic pathway, and (2) thimerosal is a potential pro-fibrotic agent in human kidney cells. We suggest that new evidence on toxicity as well as continuous surveillance in terms of fibrogenesis is required concerning thimerosal use.
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Affiliation(s)
- Maria Fernanda Hornos Carneiro
- Centre for Kidney Disease Research, School of Medicine, University of Queensland, Translational Research Institute, Kent Street, Woolloongabba, Brisbane, Queensland, Australia
- Laboratório de Toxicologia e Essencialidade de Metais, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. Do Café, s/n, Monte Alegre, Ribeirão Preto, SP, Brazil
| | - Christudas Morais
- Centre for Kidney Disease Research, School of Medicine, University of Queensland, Translational Research Institute, Kent Street, Woolloongabba, Brisbane, Queensland, Australia
| | - David M Small
- Centre for Kidney Disease Research, School of Medicine, University of Queensland, Translational Research Institute, Kent Street, Woolloongabba, Brisbane, Queensland, Australia
| | - David A Vesey
- Centre for Kidney Disease Research, School of Medicine, University of Queensland, Translational Research Institute, Kent Street, Woolloongabba, Brisbane, Queensland, Australia
| | - Fernando Barbosa
- Laboratório de Toxicologia e Essencialidade de Metais, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. Do Café, s/n, Monte Alegre, Ribeirão Preto, SP, Brazil
| | - Glenda C Gobe
- Centre for Kidney Disease Research, School of Medicine, University of Queensland, Translational Research Institute, Kent Street, Woolloongabba, Brisbane, Queensland, Australia
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Wang M, Wang Y, Zhang L, Wang J, Hong H, Wang D. Quantitative proteomic analysis reveals the mode-of-action for chronic mercury hepatotoxicity to marine medaka (Oryzias melastigma). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 130-131:123-131. [PMID: 23416409 DOI: 10.1016/j.aquatox.2013.01.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 01/16/2013] [Accepted: 01/18/2013] [Indexed: 06/01/2023]
Abstract
Mercury (Hg) is a widespread persistent pollutant in aquatic ecosystems. We investigated the protein profiles of medaka (Oryzias melastigma) liver chronically exposed to different mercuric chloride (HgCl2) concentrations (1 or 10 μg/L) for 60 d using two-dimensional difference gel electrophoresis (2D-DIGE), as well as cell ultrastructure and Hg content analysis of the hepatic tissue. The results showed that Hg exposure significantly increased metal accumulation in the liver, and subsequently damaged liver ultrastructure. Comparison of the 2D-DIGE protein profiles of the exposed and control groups revealed that the abundance of 45 protein spots was remarkably altered in response to Hg treatment. The altered spots were subjected to matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry analysis, with the resultant identification of 33 spots. These proteins were mainly involved in cytoskeleton assembly, oxidative stress, and energy production. Among them, several proteins related to mitochondrial function (e.g. respiratory metabolism) were significantly altered in the treated hepatocytes, implying that this organelle might be the primary target for Hg attack in the cells. This study provided new insights into the molecular mechanisms and/or toxic pathways by which chronic Hg hepatotoxicity affects aquatic organisms, and also provided basic information for screening potential biomarkers for aquatic Hg monitoring.
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Affiliation(s)
- Minghua Wang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China
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7
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Goines PE, Ashwood P. Cytokine dysregulation in autism spectrum disorders (ASD): possible role of the environment. Neurotoxicol Teratol 2013; 36:67-81. [PMID: 22918031 PMCID: PMC3554862 DOI: 10.1016/j.ntt.2012.07.006] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 07/03/2012] [Accepted: 07/31/2012] [Indexed: 02/07/2023]
Abstract
Autism spectrum disorders (ASD) are neurodevelopmental diseases that affect an alarming number of individuals. The etiological basis of ASD is unclear, and evidence suggests it involves both genetic and environmental factors. There are many reports of cytokine imbalances in ASD. These imbalances could have a pathogenic role, or they may be markers of underlying genetic and environmental influences. Cytokines act primarily as mediators of immunological activity but they also have significant interactions with the nervous system. They participate in normal neural development and function, and inappropriate activity can have a variety of neurological implications. It is therefore possible that cytokine dysregulation contributes directly to neural dysfunction in ASD. Further, cytokine profiles change dramatically in the face of infection, disease, and toxic exposures. Imbalances in cytokines may represent an immune response to environmental contributors to ASD. The following review is presented in two main parts. First, we discuss select cytokines implicated in ASD, including IL-1Β, IL-6, IL-4, IFN-γ, and TGF-Β, and focus on their role in the nervous system. Second, we explore several neurotoxic environmental factors that may be involved in the disorders, and focus on their immunological impacts. This review represents an emerging model that recognizes the importance of both genetic and environmental factors in ASD etiology. We propose that the immune system provides critical clues regarding the nature of the gene by environment interactions that underlie ASD pathophysiology.
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Affiliation(s)
- Paula E. Goines
- University of California, Davis, School of Veterinary Medicine, Department of Molecular Biosciences
| | - Paul Ashwood
- University of California, Davis, School of Medicine, Department of Medical Microbiology and Immunology
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Quartz crystal microbalance aptasensor for sensitive detection of mercury(II) based on signal amplification with gold nanoparticles. SENSORS 2012; 12:7080-94. [PMID: 22969338 PMCID: PMC3435967 DOI: 10.3390/s120607080] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 05/14/2012] [Accepted: 05/23/2012] [Indexed: 01/02/2023]
Abstract
We show that a short mercury-specific aptamer (MSA) along with gold nanoparticles (Au-NPs) can be used to determine Hg(II) ion by a combination of a QCM-based sensor and a flow system. The MSA binds specifically to Hg(II), and the Au-NPs can amplify the signal to enhance sensitivity. Specifically, the short thiolated MSAs are immobilized on the surface of the QCM as the capture probe, and the MSAs are linked to the Au-NPs as the linking probe. The two components can form a sandwich structure of the T-Hg(II)-T type in the presence of Hg(II) ions. This leads to change in the mass on the QCM and a change in the resonance frequency. Hg(II) can be determined with a detection limit of 0.24 ± 0.06 nM which is better by three orders of magnitude than previous methods. The sensor can be regenerated by disrupting the T-Hg(II)-T base pairs with a solution of cysteine.
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9
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Park HJ, Youn HS. Mercury induces the expression of cyclooxygenase-2 and inducible nitric oxide synthase. Toxicol Ind Health 2011; 29:169-74. [DOI: 10.1177/0748233711427048] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nuclear factor-κB (NF-κB) is a transcription factor that mediates the inducible expression of a variety of genes involved in immune and inflammatory responses. NF-κB activation induces numerous proinflammatory gene products including cytokines, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). The divalent heavy metal mercury has been used for thousands of years. Although mercury is clearly toxic to most mammalian organ systems, especially the immune system, exposure has still increased in some areas of the world. However, the underlying toxic mechanism is not clearly identified. Here, we report biochemical evidence that mercury alone induces NF-κB activation, resulting in the induced expression of COX-2 and iNOS. The results suggest that mercury can induce inflammatory diseases by lowering host defense.
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Affiliation(s)
- Hye-Jeong Park
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, Asan-Si, Chungnam, Korea
| | - Hyung-Sun Youn
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, Asan-Si, Chungnam, Korea
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Heilman JM, Burke TJ, McClain CJ, Watson WH. Transactivation of gene expression by NF-κB is dependent on thioredoxin reductase activity. Free Radic Biol Med 2011; 51:1533-42. [PMID: 21782934 PMCID: PMC3755477 DOI: 10.1016/j.freeradbiomed.2011.06.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 06/23/2011] [Accepted: 06/27/2011] [Indexed: 01/19/2023]
Abstract
The redox-sensitive transcription factor NF-κB mediates the expression of genes involved in inflammation and cell survival. Thioredoxin reductase-1 (TR1) and its substrate thioredoxin-1 act together to reduce oxidized cysteine residues within the DNA-binding domain of NF-κB and promote maximal DNA-binding activity in vitro. It is not clear, however, if NF-κB is regulated via this mechanism within living cells. The purpose of this study was to determine the mechanism of NF-κB modulation by TR1 in cells stimulated with the inflammatory cytokine tumor necrosis factor-α (TNF). In both control cells and cells depleted of TR1 activity through chemical inhibition or siRNA knockdown, TNF stimulation resulted in degradation of the cytoplasmic NF-κB inhibitor IκB-α and translocation of NF-κB to the nucleus. Similarly, the DNA-binding activity and redox state of NF-κB were unaffected by TR1 depletion. In contrast, NF-κB-mediated gene expression was markedly inhibited in cells lacking TR1 activity, suggesting that the transactivation potential of NF-κB is sensitive to changes in TR1 activity. Consistent with this concept, phosphorylation of the transactivation domain of NF-κB was inhibited in the presence of curcumin. Surprisingly, another TR1 inhibitor, 1-chloro-2,4-dinitrobenzene, had no effect, and siRNA knockdown of TR1 actually increased phosphorylation at this site. These results demonstrate that TR1 activity controls the transactivation potential of NF-κB and that more than one mechanism may mediate this effect.
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Affiliation(s)
- Jacqueline M. Heilman
- Division of Toxicology, Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Tom J. Burke
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Louisville, Louisville, KY 40292
| | - Craig J. McClain
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Louisville, Louisville, KY 40292
| | - Walter H. Watson
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Louisville, Louisville, KY 40292
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Zhang D, Deng M, Xu L, Zhou Y, Yuwen J, Zhou X. The sensitive and selective optical detection of mercury(II) ions by using a phosphorothioate DNAzyme strategy. Chemistry 2009; 15:8117-20. [PMID: 19637166 DOI: 10.1002/chem.200901268] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Dan Zhang
- College of Chemistry and Molecular Sciences, Wuhan University, Hubei, Wuhan 430072, China
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12
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Abstract
The heavy metal mercury is ubiquitously distributed in the environment resulting in permanent low-level exposure in human populations. Mercury can be encountered in three main chemical forms (elemental, inorganic, and organic) which can affect the immune system in different ways. In this review, we describe the effects of these various forms of mercury exposure on immune cells in humans and animals. In genetically susceptible mice or rats, subtoxic doses of mercury induce the production of highly specific autoantibodies as well as a generalized activation of the immune system. We review studies performed in this model and discuss their implications for the role of environmental chemicals in human autoimmunity.
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Affiliation(s)
- Jaya Vas
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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Eyer F, Felgenhauer N, Pfab R, Drasch G, Zilker T. Neither DMPS nor DMSA is Effective in Quantitative Elimination of Elemental Mercury After Intentional IV Injection. Clin Toxicol (Phila) 2008; 44:395-7. [PMID: 16809143 DOI: 10.1080/15563650600671795] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND Intravenous injection of elemental mercury (Hg) is rare and considered relatively harmless. Treatment recommendations vary and the effectiveness of chelation therapy is controversial. CASE REPORT A 27-year-old man intravenously injected 1.5 mL of elemental Hg. Within 12 hours he became febrile, tachycardic and dyspneic. Physical examination was unremarkable. X-rays showed scattered radiodense deposits in the lung, heart, intestinal wall, liver and kidney. The serum Hg level on admission was 172 microg/L and peaked on day 6 at 274 microg/L. Cumulative renal elimination during a five day oral treatment period with 2,3-dimercaptopropane-1-sulfonate (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA) was 8 mg and 3 mg, respectively. CONCLUSION Although urinary excretion could be enhanced during chelation therapy, Hg deposits in organs resulted in negligible elimination of mercury compared to the exposed dose.
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Affiliation(s)
- Florian Eyer
- Department of Toxicology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
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14
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Lee JS, Mirkin CA. Chip-Based Scanometric Detection of Mercuric Ion Using DNA-Functionalized Gold Nanoparticles. Anal Chem 2008; 80:6805-8. [DOI: 10.1021/ac801046a] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jae-Seung Lee
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Chad A. Mirkin
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
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Wiggers GA, Stefanon I, Padilha AS, Peçanha FM, Vassallo DV, Oliveira EM. Low nanomolar concentration of mercury chloride increases vascular reactivity to phenylephrine and local angiotensin production in rats. Comp Biochem Physiol C Toxicol Pharmacol 2008; 147:252-60. [PMID: 18093879 DOI: 10.1016/j.cbpc.2007.10.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 10/21/2007] [Accepted: 10/22/2007] [Indexed: 11/29/2022]
Abstract
Exposure to mercury at nanomolar level affects cardiac function but its effects on vascular reactivity have yet to be investigated. Pressor responses to phenylephrine (PHE) were investigated in perfused rat tail arteries before and after treatment with 6 nM HgCl2 during 1 h, in the presence (E+) and absence (E-) of endothelium, after L-NAME (10(-4) M), indomethacin (10(-5 )M), enalaprilate (1 microM), tempol (1 microM) and deferoxamine (300 microM) treatments. HgCl2 increased sensitivity (pD2) without modifying the maximum response (Emax) to PHE, but the pD2 increase was abolished after endothelial damage. L-NAME treatment increased pD2 and Emax. However, in the presence of HgCl2, this increase was smaller, and it did not modify Emax. After indomethacin treatment, the increase of pD2 induced by HgCl2 was maintained. Enalaprilate, tempol and deferoxamine reversed the increase of pD2 evoked by HgCl2. HgCl2 increased the angiotensin converting enzyme (ACE) activity explaining the result obtained with enalaprilate. Results suggest that at nanomolar concentrations HgCl2 increase the vascular reactivity to PHE. This response is endothelium mediated and involves the reduction of NO bioavailability and the action of reactive oxygen species. The local ACE participates in mercury actions and depends on the angiotensin II generation.
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Madureira P, Cunha EM, Aguas AP. Acute depletion and recovery of peritoneal B-1 lymphocytes in BALB/c mice after a single injection of mercury chloride. Immunopharmacol Immunotoxicol 2007; 29:311-22. [PMID: 17849274 DOI: 10.1080/08923970701513518] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The acute toxicity of mercury (Hg) to B cells was studied in the peritoneal cavity of BALB/c mice, a coelomic space where both B-1 and B-2 subsets of B lymphocytes are present. Up to 24 hr after a single in situ Hg injection, the peritoneal cavity became virtually devoid of lymphocytes, particularly of the B-1 subset. Lymphocyte depletion was more severe for B than T cells. This depletion was associated with partial lymphocyte activation (CD69(+)) at 6 hr of treatment and it was due to apoptosis rather than to necrosis. Partial recovery of both B and T cells was observed in the peritoneal cavity 48 hr after the Hg injection. The phenomenon was followed by a second decrease in peritoneal lymphocytes 72 hr after Hg. Neutrophils that entered the peritoneal cavity because of the Hg injection were resistant to apoptosis. No significant changes in lymphocyte number or subpopulation were found in the spleen and thymus of the mice up to 72 hr after the Hg treatment. We concluded that B lymphocytes were severely affected by the toxic effects of Hg. Our data suggest that Hg-induced unbalance in the repertoire of B cells, of the B-1 subset in particular, may result later in the secretion of the high titres of pathogenic autoantibodies that are found in the Hg-induced lupus disorder of BALB/c mice.
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Affiliation(s)
- P Madureira
- Laboratory of Immunology Mário-Arala Chaves, Abel Salazar Institute for Biomedical Sciences, ICBAS, University of Porto, Porto, Portugal.
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Virtanen JK, Rissanen TH, Voutilainen S, Tuomainen TP. Mercury as a risk factor for cardiovascular diseases. J Nutr Biochem 2006; 18:75-85. [PMID: 16781863 DOI: 10.1016/j.jnutbio.2006.05.001] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 04/06/2006] [Accepted: 05/03/2006] [Indexed: 11/30/2022]
Abstract
Mercury is a heavy metal that exists naturally in the environment. Major sources include the burning of fossil fuels (especially coal) and municipal waste incineration. Mercury can exist in several forms, with the most hazardous being organic methylmercury. In waterways (lakes, rivers, reservoirs, etc.), mercury is converted to methylmercury, which then accumulates in fish, especially in large predatory fish. Fish and fish products are the major--if not the only--source of methylmercury in humans. Mercury has long been recognized as a neurotoxin for humans, but in the last 10 years, its potentially harmful effects on cardiovascular diseases (CVD) have raised a cause for concern, mostly due to the proposed role of mercury in oxidative stress propagation. Some epidemiological studies have indeed found an association between increased levels of mercury in the body and risk of CVD. There are several plausible mechanisms to explain the association; these are discussed in this review. We also review the epidemiological studies that have investigated the association between mercury and CVD.
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Affiliation(s)
- Jyrki K Virtanen
- Research Institute of Public Health, University of Kuopio, PO Box 1627, 70211 Kuopio, Finland.
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Mori K, Yoshida K, Tani JI, Hoshikawa S, Ito S, Watanabe C. Methylmercury inhibits type II 5'-deiodinase activity in NB41A3 neuroblastoma cells. Toxicol Lett 2006; 161:96-101. [PMID: 16140479 DOI: 10.1016/j.toxlet.2005.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Revised: 08/01/2005] [Accepted: 08/01/2005] [Indexed: 10/25/2022]
Abstract
Methylmercury (MeHg) is a well-known neurotoxicant and prenatal exposure to MeHg results in severe brain damage. Since MeHg has a high affinity for thiol groups, we sought to determine whether MeHg inhibited type II iodothyronine deiodinase (D2) activity, by which prohormone thyroxine (T4) is converted to active thyroid hormone, 3,5,3'-triiodothyronine (T3) in the brain, using NB41A3 mouse neuroblastoma cells. In MeHg-treated cells, D2 activity was inhibited in a dose- and time-dependent manner; relatively low concentrations of MeHg (30 nM) inhibited D2. Kinetic analysis using a double reciplocal plot of D2 activity revealed competitive inhibition by MeHg. DTT protected D2 from MeHg when cells were incubated with both MeHg and DTT or when MeHg was added to the assay buffer containing DTT and cell sonicates from untreated cells. Removal of MeHg from culture medium did not recover D2 activity. These results demonstrate that MeHg inhibited D2 activity in NB41A3 cells and the selenocysteine in the catalytic subunit of D2 may be involved in the inhibitory action of MeHg. Further our results suggest that T3 deficiency due to D2 inhibition in the brain may be involved in the neurotoxicity of MeHg.
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Affiliation(s)
- Kouki Mori
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Miyagi, Japan.
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Colombo M, Hamelin C, Kouassi E, Fournier M, Bernier J. Differential effects of mercury, lead, and cadmium on IL-2 production by Jurkat T cells. Clin Immunol 2004; 111:311-22. [PMID: 15183152 DOI: 10.1016/j.clim.2004.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2003] [Accepted: 02/17/2004] [Indexed: 10/26/2022]
Abstract
Mercury, lead, and cadmium are widespread and highly toxic pollutants. The aim of this study was to determine the effects of sublethal doses of CH(3)HgCl, CdCl(2), and PbCl(2) on IL-2 production by T lymphocytes. Jurkat T cells were stimulated by triggering CD3 and CD28 molecules before, in conjunction with, or following heavy metal exposure. Heavy metals, individually or mixed together at equimolar concentrations, were used. Results demonstrated that low, noncytotoxic doses of metals induce tyrosine phosphorylation. Mercury and lead (1 microM) inhibit IL-2 production regardless of the state of T cell activation. Cadmium stimulated IL-2 production only in preactivated T cells. Surprisingly, a mixture of these three metals had no effect. We subsequently determined the effects of heavy metals on NFAT (nuclear factors of activated T cells) activity. When cells were stimulated by potent stimulation involving the CD3 and CD28 molecules, an increased NFAT activation was noted when the cells were exposed to mercury and to the metal mixture. Activation with PMA/calcium ionophores indicated that the target of heavy metals is located downstream from PKC and calcium mobilization. These results suggest that the state and mode of T cell activation are important parameters to consider in heavy metal toxicity.
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Affiliation(s)
- Myrian Colombo
- Centre de recherche en santé humaine, INRS-Institut Armand Frappier, Université du Québec, Pointe-Claire, QC, Canada
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Kim SH, Johnson VJ, Sharma RP. Mercury inhibits nitric oxide production but activates proinflammatory cytokine expression in murine macrophage: differential modulation of NF-kappaB and p38 MAPK signaling pathways. Nitric Oxide 2002; 7:67-74. [PMID: 12175822 DOI: 10.1016/s1089-8603(02)00008-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mercury is well known to adversely affect the immune system; however, little is known regarding its molecular mechanisms. Macrophages are major producers of nitric oxide (NO) and this signaling molecule is important in the regulation of immune responses. The present study was designed to determine the impact of mercury on NO and cytokine production and to investigate the signaling pathways involved. The murine macrophage cell line J774A.1 was used to study the effects of low-dose inorganic mercury on the production of NO and proinflammatory cytokines. Cells were treated with mercury in the presence or absence of lipopolysaccharide (LPS). Mercury (5-20 microM) dose-dependently decreased the production of NO in LPS-stimulated cells. Concomitant decreases in the expression of inducible nitric oxide synthase (iNOS) mRNA and protein were detected. Treatment of J774A.1 cells with mercury alone did not affect the production of NO nor the expression of iNOS mRNA or protein. Interestingly, mercury alone stimulated the expression of tumor necrosis factor alpha (TNFalpha), and increased LPS-induced TNFalpha and interleukin-6 mRNA expression. Mercury inhibited LPS-induced nuclear translocation of nuclear factor kappaB (NF-kappaB) but had no effect alone. In contrast, mercury activated p38 mitogen-activated protein kinase (p38 MAPK) and additively increased LPS-induced p38 MAPK phosphorylation. These results indicate that mercury suppresses NO synthesis by inhibition of the NF-kappaB pathway and modulates cytokine expression by p38 MAPK activation in J774A.1 macrophage cells.
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Affiliation(s)
- Sang Hyun Kim
- Department of Physiology and Pharmacology, Interdisciplinary Program of Toxicology, The University of Georgia, Athens, GA 30602-7389, USA
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