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Spulber S, Reis L, Alexe P, Ceccatelli S. Decreased activity in zebrafish larvae exposed to glyphosate-based herbicides during development-potential mediation by glucocorticoid receptor. FRONTIERS IN TOXICOLOGY 2024; 6:1397477. [PMID: 39165249 PMCID: PMC11333450 DOI: 10.3389/ftox.2024.1397477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 06/19/2024] [Indexed: 08/22/2024] Open
Abstract
Glyphosate-based herbicides (GBH) are a widely used group of pesticides that have glyphosate (GLY) as main active compound and are used to control a wide range of weeds. Experimental and epidemiological studies point to neurotoxicity and endocrine disruption as main toxic effects. The aim of this study was to investigate the effects of developmental exposure to GLY and GBH on locomotor behavior, and the possible contribution of GR-mediated signaling. We used zebrafish (Danio rerio) larvae in a continuous exposure regimen to GLY or GBH in the rearing medium. Alongside TL wildtype, we used a mutant line carrying a mutation in the GR which prevents the GR from binding to DNA (grs357), as well as a transgenic strain expressing a variant of enhanced green fluorescent protein (d4eGFP) controlled by a promoter carrying multiple GR response elements (SR4G). We found that acute exposure to GBH, but not GLY, activates GR-mediated signaling. Using a continuous developmental exposure regime, we show that wildtype larvae exposed to GBH display decreased spontaneous activity and attenuated response to environmental stimuli, a pattern of alteration similar to the one observed in grs357 mutant larvae. In addition, developmental exposure to GBH has virtually no effects on the behavior of grs357 mutant larvae. Taken together, our data indicate that developmental exposure to GBH has more pronounced effects than GLY on behavior at 5 dpf, and that interference with GR-mediated signaling may have a relevant contribution.
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Affiliation(s)
- S. Spulber
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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2
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Bottini CLJ, MacDougall-Shackleton SA. Methylmercury effects on avian brains. Neurotoxicology 2023; 96:140-153. [PMID: 37059311 DOI: 10.1016/j.neuro.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 04/03/2023] [Accepted: 04/11/2023] [Indexed: 04/16/2023]
Abstract
Methylmercury (MeHg) is a concerning contaminant due to its ubiquity and harmful effects on organisms. Although birds are important models in the neurobiology of vocal learning and adult neuroplasticity, the neurotoxic effects of MeHg are less understood in birds than mammals. We surveyed the literature on MeHg effects on biochemical changes in the avian brain. Publication rates of papers related to neurology and/or birds and/or MeHg increased with time and can be linked with historical events, regulations, and increased understanding of MeHg cycling in the environment. However, publications on MeHg effects on the avian brain remain relatively low across time. The neural effects measured to evaluate MeHg neurotoxicity in birds changed with time and researcher interest. The measures most consistently affected by MeHg exposure in birds were markers of oxidative stress. NMDA, acetylcholinesterase, and Purkinje cells also seem sensitive to some extent. MeHg exposure has the potential to affect most neurotransmitter systems but more studies are needed for validation in birds. We also review the main mechanisms of MeHg-induced neurotoxicity in mammals and compare it to what is known in birds. The literature on MeHg effects on the avian brain is limited, preventing full construction of an adverse outcome pathway. We identify research gaps for taxonomic groups such as songbirds, and age- and life-stage groups such as immature fledgling stage and adult non-reproductive life stage. In addition, results are often inconsistent between experimental and field studies. We conclude that future neurotoxicological studies of MeHg impacts on birds need to better connect the numerous aspects of exposure from molecular physiological effects to behavioural outcomes that would be ecologically or biologically relevant for birds, especially under challenging conditions.
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Affiliation(s)
- Claire L J Bottini
- University of Western Ontario, Department of Biology, 1151 Richmond St., London Ontario, N6A 5B7; Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada.
| | - Scott A MacDougall-Shackleton
- Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada; University of Western Ontario, Department of Psychology, 1151 Richmond St., London Ontario, N6A 5C2
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Puty B, Bittencourt LO, Plaça JR, de Oliveira EHC, Lima RR. Astrocyte-Like Cells Transcriptome Changes After Exposure to a Low and Non-cytotoxic MeHg Concentration. Biol Trace Elem Res 2023; 201:1151-1162. [PMID: 35378667 DOI: 10.1007/s12011-022-03225-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 03/29/2022] [Indexed: 02/07/2023]
Abstract
The central nervous system is the main target of MeHg toxicity and glial cells are the first line of defense; however, their true role remains unclear. This study aimed to identify the global map of human glial-like (U87) cells transcriptome after exposure to a non-toxic and non-lethal MeHg concentration and to investigate the related molecular changes. U87 cells were exposed upon 0.1, 0.5, and 1 µM MeHg for 4 and 24 h. Although no changes were observed in the percentage of viable cells, the metabolic viability was significantly decreased after exposure to 1 µM MeHg for 24 h; thus, the non-toxic concentration of 0.1 µM MeHg was chosen to perform microarray analysis. Significant changes in U87 cells transcriptome were observed only after 24 h. The expression of 392 genes was down regulated while 431 genes were up-regulated. Gene ontology showed alterations in biological processes (75%), cellular components (21%), and molecular functions (4%). The main pathways showed by KEGG and Reactome were cell cycle regulation and Rho GTPase signaling. The complex mechanism of U87 cells response against MeHg exposure indicates that even a low and non-toxic concentration is able to alter the gene expression profile.
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Affiliation(s)
- Bruna Puty
- Laboratory of Functional and Structural Biology, Institute of Biological Science, Federal University of Pará, Belém, Brazil
- Laboratory of Tissue Culture and Cytogenetics, Environmental Section, Evandro Chagas Institute, Ananindeua, Brazil
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Science, Federal University of Pará, Belém, Brazil
| | - Jéssica Rodrigues Plaça
- National Institute of Science and Technology in Stem Cell and Cell Therapy (INCT/CNPq) and Center for Cell-Based Therapy, CEPID/FAPESP, Ribeirão Preto, Brazil
| | | | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Science, Federal University of Pará, Belém, Brazil.
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Bose R, Spulber S, Ceccatelli S. The Threat Posed by Environmental Contaminants on Neurodevelopment: What Can We Learn from Neural Stem Cells? Int J Mol Sci 2023; 24:ijms24054338. [PMID: 36901772 PMCID: PMC10002364 DOI: 10.3390/ijms24054338] [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] [Received: 01/08/2023] [Revised: 02/03/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Exposure to chemicals may pose a greater risk to vulnerable groups, including pregnant women, fetuses, and children, that may lead to diseases linked to the toxicants' target organs. Among chemical contaminants, methylmercury (MeHg), present in aquatic food, is one of the most harmful to the developing nervous system depending on time and level of exposure. Moreover, certain man-made PFAS, such as PFOS and PFOA, used in commercial and industrial products including liquid repellants for paper, packaging, textile, leather, and carpets, are developmental neurotoxicants. There is vast knowledge about the detrimental neurotoxic effects induced by high levels of exposure to these chemicals. Less is known about the consequences that low-level exposures may have on neurodevelopment, although an increasing number of studies link neurotoxic chemical exposures to neurodevelopmental disorders. Still, the mechanisms of toxicity are not identified. Here we review in vitro mechanistic studies using neural stem cells (NSCs) from rodents and humans to dissect the cellular and molecular processes changed by exposure to environmentally relevant levels of MeHg or PFOS/PFOA. All studies show that even low concentrations dysregulate critical neurodevelopmental steps supporting the idea that neurotoxic chemicals may play a role in the onset of neurodevelopmental disorders.
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Zebrafish as a Potential Model for Neurodegenerative Diseases: A Focus on Toxic Metals Implications. Int J Mol Sci 2023; 24:ijms24043428. [PMID: 36834835 PMCID: PMC9959844 DOI: 10.3390/ijms24043428] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/31/2023] [Accepted: 02/05/2023] [Indexed: 02/11/2023] Open
Abstract
In the last century, industrial activities increased and caused multiple health problems for humans and animals. At this moment, heavy metals are considered the most harmful substances for their effects on organisms and humans. The impact of these toxic metals, which have no biological role, poses a considerable threat and is associated with several health problems. Heavy metals can interfere with metabolic processes and can sometimes act as pseudo-elements. The zebrafish is an animal model progressively used to expose the toxic effects of diverse compounds and to find treatments for different devastating diseases that human beings are currently facing. This review aims to analyse and discuss the value of zebrafish as animal models used in neurological conditions, such as Alzheimer's disease (AD), and Parkinson's disease (PD), particularly in terms of the benefits of animal models and the limitations that exist.
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Dinarello A, Tesoriere A, Martini P, Fontana CM, Volpato D, Badenetti L, Terrin F, Facchinello N, Romualdi C, Carnevali O, Dalla Valle L, Argenton F. Zebrafish Mutant Lines Reveal the Interplay between nr3c1 and nr3c2 in the GC-Dependent Regulation of Gene Transcription. Int J Mol Sci 2022; 23:2678. [PMID: 35269817 PMCID: PMC8910431 DOI: 10.3390/ijms23052678] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/24/2022] [Accepted: 02/24/2022] [Indexed: 02/04/2023] Open
Abstract
Glucocorticoids mainly exert their biological functions through their cognate receptor, encoded by the nr3c1 gene. Here, we analysed the glucocorticoids mechanism of action taking advantage of the availability of different zebrafish mutant lines for their receptor. The differences in gene expression patterns between the zebrafish gr knock-out and the grs357 mutant line, in which a point mutation prevents binding of the receptor to the hormone-responsive elements, reveal an intricate network of GC-dependent transcription. Particularly, we show that Stat3 transcriptional activity mainly relies on glucocorticoid receptor GR tethering activity: several Stat3 target genes are induced upon glucocorticoid GC exposure both in wild type and in grs357/s357 larvae, but not in gr knock-out zebrafish. To understand the interplay between GC, their receptor, and the mineralocorticoid receptor, which is evolutionarily and structurally related to the GR, we generated an mr knock-out line and observed that several GC-target genes also need a functional mineralocorticoid receptor MR to be correctly transcribed. All in all, zebrafish mutants and transgenic models allow in vivo analysis of GR transcriptional activities and interactions with other transcription factors such as MR and Stat3 in an in-depth and rapid way.
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Affiliation(s)
- Alberto Dinarello
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
| | - Annachiara Tesoriere
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
| | - Paolo Martini
- Department of Molecular and Translational Medicine, University of Brescia, 25121 Brescia, Italy;
| | - Camilla Maria Fontana
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
| | - Davide Volpato
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
| | - Lorenzo Badenetti
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
| | - Francesca Terrin
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
| | - Nicola Facchinello
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
| | - Chiara Romualdi
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
| | - Oliana Carnevali
- Department of Life and Environmental Sciences, Università Politecnica delle Marche, 60131 Ancona, Italy;
| | - Luisa Dalla Valle
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
| | - Francesco Argenton
- Department of Biology, University of Padova, 35121 Padova, Italy; (A.D.); (A.T.); (C.M.F.); (D.V.); (L.B.); (F.T.); (N.F.); (C.R.); (F.A.)
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Glazer L, Brennan CH. Developmental Exposure to Low Concentrations of Methylmercury Causes Increase in Anxiety-Related Behaviour and Locomotor Impairments in Zebrafish. Int J Mol Sci 2021; 22:10961. [PMID: 34681620 PMCID: PMC8535691 DOI: 10.3390/ijms222010961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/22/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022] Open
Abstract
Methylmercury (MeHg) is a ubiquitous pollutant shown to cause developmental neurotoxicity, even at low levels. However, there is still a large gap in our understanding of the mechanisms linking early-life exposure to life-long behavioural impairments. Our aim was to characterise the short- and long-term effects of developmental exposure to low doses of MeHg on anxiety-related behaviours in zebrafish, and to test the involvement of neurological pathways related to stress-response. Zebrafish embryos were exposed to sub-acute doses of MeHg (0, 5, 10, 15, 30 nM) throughout embryo-development, and tested for anxiety-related behaviours and locomotor activity at larval (light/dark locomotor activity) and adult (novel tank and tap assays) life-stages. Exposure to all doses of MeHg caused increased anxiety-related responses; heightened response to the transition from light to dark in larvae, and a stronger dive response in adults. In addition, impairment in locomotor activity was observed in the higher doses in both larvae and adults. Finally, the expressions of several neural stress-response genes from the HPI-axis and dopaminergic system were found to be disrupted in both life-stages. Our results provide important insights into dose-dependent differences in exposure outcomes, the development of delayed effects over the life-time of exposed individuals and the potential mechanisms underlying these effects.
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Affiliation(s)
- Lilah Glazer
- Nanchang Joint Programme, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Caroline H. Brennan
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK;
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Gochfeld M, Burger J. Mercury interactions with selenium and sulfur and the relevance of the Se:Hg molar ratio to fish consumption advice. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:18407-18420. [PMID: 33507504 PMCID: PMC8026698 DOI: 10.1007/s11356-021-12361-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 01/02/2021] [Indexed: 05/20/2023]
Abstract
Eating fish is often recommended as part of a healthful diet. However, fish, particularly large predatory fish, can contain significant levels of the highly toxic methylmercury (MeHg). Ocean fish in general also contain high levels of selenium (Se), which is reported to confer protection against toxicity of various metals including mercury (Hg). Se and Hg have a high mutual binding affinity, and each can reduce the toxicity of the other. This is an evolving area of extensive research and controversy with variable results in the animal and epidemiologic literature. MeHg is toxic to many organ systems through high affinity for -SH (thiol) ligands on enzymes and microtubules. Hg toxicity also causes oxidative damage particularly to neurons in the brain. Hg is a potent and apparently irreversible inhibitor of the selenoenzymes, glutathione peroxidases (GPX), and thioredoxin reductases (TXNRD) that are important antioxidants, each with a selenocysteine (SeCys) at the active site. Hg binding to the SeCys inhibits these enzymes, accounting in part for the oxidative damage that is an important manifestation of Hg toxicity, particularly if there is not a pool of excess Se to synthesize new enzymes. A molar excess of Se reflected in an Se:Hg molar ratio > 1 is often invoked as evidence that the Hg content can be discounted. Some recent papers now suggest that if the Se:Hg molar ratio exceeds 1:1, the fish is safe and the mercury concentration can be ignored. Such papers suggested that the molar ratio rather than the Hg concentration should be emphasized in fish advisories. This paper examines some of the limitations of current understanding of the Se:Hg molar ratio in guiding fish consumption advice; Se is certainly an important part of the Hg toxicity story, but it is not the whole story. We examine how Hg toxicity relates also to thiol binding. We suggest that a 1:1 molar ratio cannot be relied on because not all of the Se in fish or in the fish eater is available to interact with Hg. Moreover, in some fish, Se levels are sufficiently high to warrant concern about Se toxicity.
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Affiliation(s)
- Michael Gochfeld
- Rutgers Biomedical and Health Sciences, School of Public Health, Piscataway, NJ, USA.
- Environmental and Occupational Health Sciences Institutes, Rutgers University, Piscataway, NJ, 08854, USA.
| | - Joanna Burger
- Environmental and Occupational Health Sciences Institutes, Rutgers University, Piscataway, NJ, 08854, USA
- Division of Life Science, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854, USA
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Branco V, Aschner M, Carvalho C. Neurotoxicity of mercury: an old issue with contemporary significance. ADVANCES IN NEUROTOXICOLOGY 2021; 5:239-262. [PMID: 34263092 PMCID: PMC8276940 DOI: 10.1016/bs.ant.2021.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mercury exerts a variety of toxic effects, depending on the specific compound and route of exposure. However, neurotoxicity in virtue of its consequence to health causes the greatest concern for toxicologists. This is particularly true regarding fetal development, where neurotoxic effects are much more severe than in adults, and the toxicity threshold is lower. Here, we review the major concepts regarding the neurotoxicity of mercury compounds (mercury vapor; methylmercury and ethylmercury), from exposure routes to toxicokinetic particularities leading to brain deposition and the development of neurotoxic effects. Albeit research on the neurotoxicity of mercury compounds has significantly advanced from the second half of the twentieth century onwards, several grey areas regarding the mechanism of toxicity still exist. Thus, we emphasize research advances during the last two decades concerning the molecular interactions of mercury which cause neurotoxic effects. Highlights include the disruption of glutamate signaling and excitotoxicity resulting from exposure to mercury and the interaction with redox active residues such as cysteines and selenocysteines which are the premise accounting for the disruption of redox homeostasis caused by mercurials. We also address how immunotoxic effects at the CNS, namely microglia and astrocyte activation modulate developmental neurotoxicity, a major topic in contemporary research.
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Affiliation(s)
- Vasco Branco
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, USA
| | - Cristina Carvalho
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
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Cediel Ulloa A, Gliga A, Love TM, Pineda D, Mruzek DW, Watson GE, Davidson PW, Shamlaye CF, Strain JJ, Myers GJ, van Wijngaarden E, Ruegg J, Broberg K. Prenatal methylmercury exposure and DNA methylation in seven-year-old children in the Seychelles Child Development Study. ENVIRONMENT INTERNATIONAL 2021; 147:106321. [PMID: 33340986 DOI: 10.1016/j.envint.2020.106321] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/06/2020] [Accepted: 12/02/2020] [Indexed: 05/27/2023]
Abstract
BACKGROUND Methylmercury (MeHg) is present in fish and is a neurotoxicant at sufficiently high levels. One potential mechanism of MeHg toxicity early in life is epigenetic dysregulation that may affect long-term neurodevelopment. Altered DNA methylation of nervous system-related genes has been associated with adult mental health outcomes. OBJECTIVE To assess associations between prenatal MeHg exposure and DNA methylation (at the cytosine of CG dinucleotides, CpGs) in three nervous system-related genes, encoding brain-derived neurotropic factor (BDNF), glutamate receptor subunit NR2B (GRIN2B), and the glucocorticoid receptor (NR3C1), in children who were exposed to MeHg in utero. METHODS We tested 406 seven-year-old Seychellois children participating in the Seychelles Child Development Study (Nutrition Cohort 2), who were prenatally exposed to MeHg from maternal fish consumption. Total mercury in maternal hair (prenatal MeHg exposure measure) collected during pregnancy was measured using atomic absorption spectroscopy. Methylation in DNA from the children's saliva was measured by pyrosequencing. To assess associations between prenatal MeHg exposure and CpG methylation at seven years of age, we used multivariable linear regression models adjusted for covariates. RESULTS We identified associations with prenatal MeHg exposure for DNA methylation of one GRIN2B CpG and two NR3C1 CpGs out of 12 total CpG sites. Higher prenatal MeHg was associated with higher methylation for each CpG site. For example, NR3C1 CpG3 had an expected increase of 0.03-fold for each additional 1 ppm of prenatal MeHg (B = 0.030, 95% CI 0.001, 0.059; p = 0.047). Several CpG sites associated with MeHg are located in transcription factor binding sites and the observed methylation changes are predicted to lead to lower gene expression. CONCLUSIONS In a population of people who consume large amounts of fish, we showed that higher prenatal MeHg exposure was associated with differential DNA methylation at seven years of age at specific CpG sites that may influence neurodevelopment and mental health.
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Affiliation(s)
- Andrea Cediel Ulloa
- Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77 Stockholm, Sweden; Department of Organism Biology, Uppsala University, Kåbovägen 4, 752 36 Uppsala, Sweden
| | - Anda Gliga
- Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77 Stockholm, Sweden
| | - Tanzy M Love
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Daniela Pineda
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Scheelevägen 8, 22185 Lund, Sweden
| | - Daniel W Mruzek
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Gene E Watson
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Philip W Davidson
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | | | - J J Strain
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland Bt52 1SA, UK
| | - Gary J Myers
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Edwin van Wijngaarden
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Joelle Ruegg
- Department of Organism Biology, Uppsala University, Kåbovägen 4, 752 36 Uppsala, Sweden
| | - Karin Broberg
- Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77 Stockholm, Sweden; Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Scheelevägen 8, 22185 Lund, Sweden.
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11
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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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Chen N, Tang X, Ye Z, Wang S, Xiao X. Methylmercury disrupts autophagic flux by inhibiting autophagosome-lysosome fusion in mouse germ cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 198:110667. [PMID: 32339925 DOI: 10.1016/j.ecoenv.2020.110667] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 04/03/2020] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
Methylmercury (MeHg) is an extremely toxic environmental pollutant that can cause serious male reproductive developmental dysplasia in humans and animals. However, the molecular mechanisms underlying MeHg-induced male reproductive injury are not fully clear. The purpose of this study was to explore whether mitophagy and lysosome dysfunction contribute to MeHg-induced apoptosis of germ cell and to determine the potential mechanism. First, we confirmed the exposure of GC2-spd cells to mercury. In GC2-spd cells (a mouse spermatocyte cell line), we found that MeHg treatment led to an obvious increase of cell apoptosis accompanied by a marked rise of LC3-II expression and an elevated number of autophagosomes. These results were associated with the induction of oxidative stress and mitophagy. Interestingly, we found that MeHg did not promote but prevented autophagosome-lysosome fusion by impairing the lysosome function. Furthermore, as a lysosome inhibitor, chloroquine pre-treatment obviously enhanced LC3-II expression and mitophagy formation in MeHg-treated cells. This further proved that the induction of mitophagy and the injury of the lysosome played an important role in the GC2-spd cell apoptosis induced by MeHg. Our findings indicate that MeHg caused apoptosis in the GC2-spd cells, which were dependent on oxidative stress-mediated mitophagy and the lysosome damaging-mediated inhibition of autophagic flux induced by MeHg.
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Affiliation(s)
- Na Chen
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Xiaofeng Tang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Zhaoyang Ye
- Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Shanshan Wang
- Key Laboratory of Agro-product Safety and Quality, Institute of Quality Standards & Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing, 100081, PR China.
| | - Xianjin Xiao
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China.
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Wang Y, Zhou S, Ma H, Shi JS, Lu YF. Investigation of the differential transport mechanism of cinnabar and mercury containing compounds. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2019; 66:83-90. [PMID: 30639899 DOI: 10.1016/j.etap.2018.12.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 12/01/2018] [Accepted: 12/24/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Cinnabar has a long history of uses in Chinese traditional medicines as an ingredient in various remedies. However, the detailed mechanism of cinnabar in medication remains unclear, and the toxicity of cinnabar has been a debate due to its containing mercury sulfide. This study was designed to investigate the differential transport mechanism of cinnabar and other Hg-containing compounds HgCl2, MeHg and HgS, and to determine if organic anion transporters OAT1 and OAT3 were involved in the differential transport mechanism. MATERIALS AND METHODS The 293T cells were employed to investigate and compare the differential transport mechanism of cinnabar and HgCl2, MeHg and HgS. Cells were incubated with a low dose (5 μM HgCl2 and MeHg, 200 μM HgS and cinnabar), medium dose (10 μM HgCl2 and MeHg, 400 μM HgS and cinnabar), and high dose (20 μM HgCl2 and MeHg, 800 μM HgS and cinnabar) of HgCl2, MeHg, HgS and cinnabar for 24 h. Following treatment, the cells were collected and the cell viability was determined by MTT assay. The intracellular mercury content was measured at 1, 4, and 24 h after treatment with 10 μM of the tested agents by an atomic fluorescence spectrophotometer. The effect of these tested agents on mitochondrial respiration was determined in a high-resolution oxygraphyat 24 h following treatment. Furthermore, the effect of modulation of expression of transporters OAT1 and OAT3 on the transport and cytotoxicity of the tested agents was evaluated. The up and down regulation of OAT1 and OAT3 were achieved by overexpression and siRNA transfection, respectively. RESULTS Compared with HgCl2 and MeHg, the cytotoxicity of cinnabar and HgS was lower, with cell viability at the high dose cinnabar and HgS being about 65%, while MeHg and HgCl2 were 40% and 20%, respectively. The intracellular mercury accumulation was time-dependent. At 24 h the intracellular concentrations of HgCl2 and MeHg were about 7 and 5 times higher, respectively, than that of cinnabar. No significant difference was found in the intracellular mercury content in cells treated with cinnabar compared to HgS. The knockdown and overexpression of the transporter OAT1 resulted in significant reduction and increase, respectively, in mercury accumulation in HgCl2 -treated cells in relative to control cells, while no significant changes were observed in cells treated with cinnabar, MeHg, and HgS. In addition, the knockdown and overexpression of the transporter OAT3 caused significant reduction and increase, respectively, in mercury accumulation in both HgCl2 and MeHg-treated cells in relative to control cells, while no significant changes were observed in cells treated with cinnabar and HgS. Furthermore, it was found that cells transfected with siOAT1 caused significant resistance to the cytotoxicity induced by HgCl2, while no noticeable changes in cell viability were observed in cells treated with other tested agents. Additionally, cells transfected with OAT3 did not change cell sensitivity to cytotoxicity induced by all of the four tested agents. CONCLUSION This study demonstrates that differential transport and accumulation of mercury in 293T cells exists among cinnabar and the three mercury-containing compounds HgCl2, MeHg and HgS, leading to distinct sensitivity to mercury induced cytotoxicity. The kidney organic anion transporters OAT1 and OAT3 are partially involved in the regulation of the transport of HgCl2 and MeHg, but not in the regulation of the transport of cinnabar.
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Affiliation(s)
- Yang Wang
- Joint International Research Laboratory of Ethnomedicine, Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical College, Guizhou, China
| | - Shaoyu Zhou
- Joint International Research Laboratory of Ethnomedicine, Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical College, Guizhou, China; Department of Environmental Health, School of Public Health, Indiana University, Bloomington, IN, USA
| | - Honghong Ma
- Joint International Research Laboratory of Ethnomedicine, Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical College, Guizhou, China
| | - Jing-Shan Shi
- Joint International Research Laboratory of Ethnomedicine, Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical College, Guizhou, China
| | - Yuan-Fu Lu
- Joint International Research Laboratory of Ethnomedicine, Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical College, Guizhou, China.
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