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Shinoda Y, Akiyama M, Toyama T. Potential Association between Methylmercury Neurotoxicity and Inflammation. Biol Pharm Bull 2023; 46:1162-1168. [PMID: 37661394 DOI: 10.1248/bpb.b23-00075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Methylmercury (MeHg) is the causal substrate of Minamata disease and a major environmental toxicant. MeHg is widely distributed, mainly in the ocean, meaning its bioaccumulation in seafood is a considerable problem for human health. MeHg has been intensively investigated and is known to induce inflammatory responses and neurodegeneration. However, the relationship between MeHg-induced inflammatory responses and neurodegeneration is not understood. In the present review, we first describe recent findings showing an association between inflammatory responses and certain MeHg-unrelated neurological diseases caused by neurodegeneration. In addition, cell-specific MeHg-induced inflammatory responses are summarized for the central nervous system including those of microglia, astrocytes, and neurons. We also describe MeHg-induced inflammatory responses in peripheral cells and tissue, such as macrophages and blood. These findings provide a concept of the relationship between MeHg-induced inflammatory responses and neurodegeneration, as well as direction for future research of MeHg-induced neurotoxicity.
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Affiliation(s)
- Yo Shinoda
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Masahiro Akiyama
- Research Center for Drug Discovery, Faculty of Pharmacy and Graduate School of Pharmaceutical Sciences, Keio University
| | - Takashi Toyama
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University
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Branco V, Caito S, Farina M, Teixeira da Rocha J, Aschner M, Carvalho C. Biomarkers of mercury toxicity: Past, present, and future trends. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2017; 20:119-154. [PMID: 28379072 PMCID: PMC6317349 DOI: 10.1080/10937404.2017.1289834] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Mercury (Hg) toxicity continues to represent a global health concern. Given that human populations are mostly exposed to low chronic levels of mercurial compounds (methylmercury through fish, mercury vapor from dental amalgams, and ethylmercury from vaccines), the need for more sensitive and refined tools to assess the effects and/or susceptibility to adverse metal-mediated health risks remains. Traditional biomarkers, such as hair or blood Hg levels, are practical and provide a reliable measure of exposure, but given intra-population variability, it is difficult to establish accurate cause-effect relationships. It is therefore important to identify and validate biomarkers that are predictive of early adverse effects prior to adverse health outcomes becoming irreversible. This review describes the predominant biomarkers used by toxicologists and epidemiologists to evaluate exposure, effect and susceptibility to Hg compounds, weighing on their advantages and disadvantages. Most importantly, and in light of recent findings on the molecular mechanisms underlying Hg-mediated toxicity, potential novel biomarkers that might be predictive of toxic effect are presented, and the applicability of these parameters in risk assessment is examined.
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Affiliation(s)
- Vasco Branco
- a Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia , Universidade de Lisboa , Lisboa , Portugal
| | - Sam Caito
- b Department of Molecular Pharmacology , Albert Einstein College of Medicine , Bronx , New York , USA
| | - Marcelo Farina
- c Departamento de Bioquímica, Centro de Ciências Biológicas , Universidade Federal de Santa Catarina , Florianópolis , Brazil
| | - João Teixeira da Rocha
- d Departamento Bioquímica e Biologia Molecular , Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Michael Aschner
- b Department of Molecular Pharmacology , Albert Einstein College of Medicine , Bronx , New York , USA
| | - Cristina Carvalho
- a Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia , Universidade de Lisboa , Lisboa , Portugal
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Farina M, Aschner M. Methylmercury-Induced Neurotoxicity: Focus on Pro-oxidative Events and Related Consequences. ADVANCES IN NEUROBIOLOGY 2017; 18:267-286. [DOI: 10.1007/978-3-319-60189-2_13] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Liu W, Xu Z, Yang T, Deng Y, Xu B, Feng S. Tea Polyphenols Protect Against Methylmercury-Induced Cell Injury in Rat Primary Cultured Astrocytes, Involvement of Oxidative Stress and Glutamate Uptake/Metabolism Disorders. Mol Neurobiol 2016; 53:2995-3009. [PMID: 25952541 DOI: 10.1007/s12035-015-9161-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/25/2015] [Indexed: 02/06/2023]
Abstract
Methylmercury (MeHg) is an extremely dangerous environmental contaminant, accumulating preferentially in CNS and causing a series of cytotoxic effects. However, the precise mechanisms are still incompletely understood. The current study explored the mechanisms that contribute to MeHg-induced cell injury focusing on the oxidative stress and Glu uptake/metabolism disorders in rat primary cultured astrocytes. Moreover, the neuroprotective effects of tea polyphenols (TP), a natural antioxidant, against MeHg cytotoxicity were also investigated. Astrocytes were exposed to 0, 2.5, 5, 10, and 20 μM MeHgCl for 6-30 h, or pretreated with 50, 100, 200, and 400 μM TP for 1-12 h; cell viability and LDH release were then determined. For further experiments, 50, 100, and 200 μM of TP pretreatment for 6 h followed by 10 μM MeHgCl for 24 h were performed for the examination of the responses of astrocytes, specifically addressing NPSH levels, ROS generation, ATPase activity, the expressions of Nrf2 pathway as well as Glu metabolism enzyme GS and Glu transporters (GLAST and GLT-1). Exposure of MeHg resulted in damages of astrocytes, which were shown by a loss of cell viability, and supported by high levels of LDH release, morphological changes, apoptosis rates, and NPSH depletion. In addition, astrocytes were sensitive to MeHg-mediated oxidative stress, a finding that is consistent with ROS overproduction; Nrf2 as well as its downstream genes HO-1 and γ-GCSh were markedly upregulated. Moreover, MeHg significantly inhibited GS activity, as well as expressions of GS, GLAST, and GLT-1. On the contrary, pretreatment with TP presented a concentration-dependent prevention against MeHg-mediated cytotoxic effects of astrocytes. In conclusion, the findings clearly indicated that MeHg aggravated oxidative stress and Glu uptake/metabolism dysfunction in astrocytes. TP possesses some abilities to prevent MeHg cytotoxicity through its antioxidative properties.
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Affiliation(s)
- Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, Liaoning province, China
| | - Zhaofa Xu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, Liaoning province, China.
| | - Tianyao Yang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, Liaoning province, China
| | - Yu Deng
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, Liaoning province, China
| | - Bin Xu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, Liaoning province, China
| | - Shu Feng
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, Liaoning province, China
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Silva de Paula E, Carneiro MFH, Grotto D, Hernandes LC, Antunes LMG, Barbosa F. Protective effects of niacin against methylmercury-induced genotoxicity and alterations in antioxidant status in rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 79:174-183. [PMID: 26914397 DOI: 10.1080/15287394.2015.1137264] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This study investigates the potential beneficial effects of niacin (NA; vitamin B3) supplementation in rats chronically exposed to methylmercury (MeHg). Animals were randomly assigned to one of 4 groups (n = 6): Group I, control, received distilled water by gavage; Group II, received MeHg (100 µg/kg/d) by gavage; Group III, received NA (50 mg/kg/d) in drinking water; Group IV, received MeHg (100 µg/kg/d) by gavage + NA (50 mg/kg/d) in drinking water. Biochemical parameters levels of glucose, triglycerides, total cholesterol and fractions, and enzyme activities aspartate transaminase (AST) and alanine transaminase (ALT) were determined. Further, oxidative stress markers activity of glutathione peroxidase (GPx) and catalase (CAT) activity, as well as levels of reduced glutathione (GSH), malondialdehyde (MDA), and nitric oxide, were examined, and the comet assay was performed, using blood/plasma. Hg levels were measured in blood, brain, and kidneys of animals. Our results demonstrated that NA reduced adverse effects produced by MeHg. The mechanism underlying these effects appears to be related to the intrinsic antioxidant potential of NA. Considering the beneficial effects attributed to NA following MeHg exposure and that fish are the main source of both NA and MeHg, future studies need to evaluate the potential counteractive effect of NA against the adverse consequences of MeHg exposure in fish-eating populations.
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Affiliation(s)
- Eloisa Silva de Paula
- a Laboratório de Toxicologia e Essencialidade de Metais , Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Monte Alegre , Ribeirão Preto , São Paulo , Brazil
| | - Maria Fernanda Hornos Carneiro
- a Laboratório de Toxicologia e Essencialidade de Metais , Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Monte Alegre , Ribeirão Preto , São Paulo , Brazil
| | - Denise Grotto
- b Programa de Pós-Graduação em Ciências Farmacêuticas , Universidade de Sorocaba , Sorocaba , São Paulo , Brazil
| | - Lívia Cristina Hernandes
- c Laboratório de Nutrigenômica , Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Monte Alegre , Ribeirão Preto , São Paulo , Brazil
| | - Lusânia Maria Greggi Antunes
- c Laboratório de Nutrigenômica , Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Monte Alegre , Ribeirão Preto , São Paulo , Brazil
| | - Fernando Barbosa
- a Laboratório de Toxicologia e Essencialidade de Metais , Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Monte Alegre , Ribeirão Preto , São Paulo , Brazil
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Yuntao F, Chenjia G, Panpan Z, Wenjun Z, Suhua W, Guangwei X, Haifeng S, Jian L, Wanxin P, Yun F, Cai J, Aschner M, Rongzhu L. Role of autophagy in methylmercury-induced neurotoxicity in rat primary astrocytes. Arch Toxicol 2014; 90:333-45. [PMID: 25488884 DOI: 10.1007/s00204-014-1425-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 11/25/2014] [Indexed: 11/30/2022]
Abstract
Autophagy is an evolutionarily conserved process in which cytoplasmic proteins and organelles are degraded and recycled for reuse. There are numerous reports on the role of autophagy in cell growth and death; however, the role of autophagy in methylmercury (MeHg)-induced neurotoxicity has yet to be identified. We studied the role of autophagy in MeHg-induced neurotoxicity in astrocytes. MeHg reduced astrocytic viability in a concentration- and time-dependent manner, and induced apoptosis. Pharmacological inhibition of autophagy with 3-methyladenine or chloroquine, as well as the silencing of the autophagy-related protein 5, increased MeHg-induced cytotoxicity and the ratio of apoptotic astrocytes. Conversely, rapamycin, an autophagy inducer, along with as N-acetyl-L-cysteine, a precursor of reduced glutathione, decreased MeHg-induced toxicity and the ratio of apoptotic astrocytes. These results indicated that MeHg-induced neurotoxicity was reduced, at least in part, through the activation of autophagy. Accordingly, modulation of autophagy may offer a new avenue for attenuating MeHg-induced neurotoxicity.
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Affiliation(s)
- Fang Yuntao
- Department of Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Guo Chenjia
- Department of Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Zhang Panpan
- Department of Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Zhao Wenjun
- Department of Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Wang Suhua
- Department of Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Xing Guangwei
- Department of Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Shi Haifeng
- Institute of Life Sciences, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Lu Jian
- Department of Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Peng Wanxin
- Department of Biology, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Feng Yun
- Department of Pharmacology, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Jiyang Cai
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX, 77550-1106, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Lu Rongzhu
- Department of Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, China.
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Kim J, Yang M, Son Y, Jang H, Kim D, Kim JC, Kim SH, Kang MJ, Im HI, Shin T, Moon C. Glial activation with concurrent up-regulation of inflammatory mediators in trimethyltin-induced neurotoxicity in mice. Acta Histochem 2014; 116:1490-500. [PMID: 25265880 DOI: 10.1016/j.acthis.2014.09.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Trimethyltin (TMT), a potent neurotoxic chemical, causes dysfunction and neuroinflammation in the brain, particularly in the hippocampus. The present study assessed TMT-induced glial cell activation and inflammatory cytokine alterations in the mouse hippocampus, BV-2 microglia, and primary cultured astrocytes. In the mouse hippocampus, TMT treatment significantly increased the expression of glial cell markers, including the microglial marker ionized calcium-binding adapter molecule 1 and the astroglial marker glial fibrillary acidic protein. The expression of M1 and M2 microglial markers (inducible nitric oxide synthase [iNOS] and CD206, respectively) and pro-inflammatory cytokines (interleukin [IL]-1β, IL-6 and tumor necrosis factor [TNF]-α) were significantly increased in the mouse hippocampus following TMT treatment. In BV-2 microglia, iNOS, IL-1β, TNF-α, and IL-6 expression increased significantly, whereas arginase-1 and CD206 expression decreased significantly after TMT treatment in a time- and concentration-dependent manner. In primary cultured astrocytes, iNOS, arginase-1, IL-1β, TNF-α, and IL-6 expression increased significantly, whereas IL-10 expression decreased significantly after TMT treatment in a time- and concentration-dependent manner. These results indicate that significant up-regulation of pro-inflammatory signals in TMT-induced neurotoxicity may be associated with pathological processing of TMT-induced neurodegeneration.
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Majumdar AS, Nirwane A, Kamble R. Coenzyme q10 abrogated the 28 days aluminium chloride induced oxidative changes in rat cerebral cortex. Toxicol Int 2014; 21:214-21. [PMID: 25253934 PMCID: PMC4170566 DOI: 10.4103/0971-6580.139814] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Objective: The present study was designed to elucidate the impact of oral administration of aluminium chloride for 28 days with respect to oxidative stress in the cerebral cortex of female rats. Further, to investigate the potentials of Coenzyme (Co) Q10 (4, 8, and 12 mg/kg, i.p.) in mitigating the detrimental changes. Materials and Methods: Biochemical estimations of cerebral lipid peroxidation (LPO), reduced glutathione (GSH), vitamin E and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were carried out after 28 days of aluminium chloride (AlCl3) and Co Q10 exposures along with histopathological examination of cerebral cortex of the rats. Results: Subacute exposure to AlCl3(5 mg/kg) led to significant decrease in levels of GSH, vitamin E and activities of SOD, CAT, GPx, and an increase in LPO of cerebral cortex. These aberrations were restored by Co Q10 (12 mg/kg, i.p.). This protection offered was comparable to that of L-deprenyl (1 mg/kg, i.p.) which served as a reference standard. Histopathological evaluations confirmed that the normal cerebral morphology was maintained by Co Q10. Conclusion: Thus, AlCl3 exposure hampers the activities of various antioxidant enzymes and induces oxidative stress in cerebral cortex of female Wistar rats. Supplementation with intraperitoneal Co Q10 abrogated these deleterious effects of AlCl3.
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Affiliation(s)
- Anuradha S Majumdar
- Department of Pharmacology, Bombay College of Pharmacy, Kalina, Mumbai, Maharashtra, India
| | - Abhijit Nirwane
- Department of Pharmacology, Bombay College of Pharmacy, Kalina, Mumbai, Maharashtra, India
| | - Rahul Kamble
- Department of Pharmacology, Bombay College of Pharmacy, Kalina, Mumbai, Maharashtra, India
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Caito S, Zeng H, Aschner JL, Aschner M. Methylmercury alters the activities of Hsp90 client proteins, prostaglandin E synthase/p23 (PGES/23) and nNOS. PLoS One 2014; 9:e98161. [PMID: 24852575 PMCID: PMC4031136 DOI: 10.1371/journal.pone.0098161] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/29/2014] [Indexed: 01/14/2023] Open
Abstract
Methylmercury (MeHg) is a persistent pollutant with known neurotoxic effects. We have previously shown that astrocytes accumulate MeHg and play a prominent role in mediating MeHg toxicity in the central nervous system (CNS) by altering glutamate signaling, generating oxidative stress, depleting glutathione (GSH) and initiating lipid peroxidation. Interestingly, all of these pathways can be regulated by the constitutively expressed, 90-kDa heat shock protein, Hsp90. As Hsp90 function is regulated by oxidative stress, we hypothesized that MeHg disrupts Hsp90-client protein functions. Astrocytes were treated with MeHg and expression of Hsp90, as well as the abundance of complexes of Hsp90-neuronal nitric oxide synthase (nNOS) and Hsp90-prostaglandin E synthase/p23 (PGES/p23) were assessed. MeHg exposure decreased Hsp90 protein expression following 12 h of treatment while shorter exposures had no effect on Hsp90 protein expression. Interestingly, following 1 or 6 h of MeHg exposure, Hsp90 binding to PGES/p23 or nNOS was significantly increased, resulting in increased prostaglandin E2 (PGE2) synthesis from MeHg-treated astrocytes. These effects were attenuated by the Hsp90 antagonist, geldanmycin. NOS activity was increased following MeHg treatment while cGMP formation was decreased. This was accompanied by an increase in •O2− and H2O2 levels, suggesting that MeHg uncouples NO formation from NO-dependent signaling and increases oxidative stress. Altogether, our data demonstrates that Hsp90 interactions with client proteins are increased following MeHg exposure, but over time Hsp90 levels decline, contributing to oxidative stress and MeHg-dependent excitotoxicity.
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Affiliation(s)
- Samuel Caito
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Heng Zeng
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Judy L Aschner
- Department of Pediatrics and Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine of Yeshiva University and Children's Hospital at Montefiore, Bronx, New York, United States of America
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America; Department of Pediatrics and Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine of Yeshiva University and Children's Hospital at Montefiore, Bronx, New York, United States of America; The Kennedy Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
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