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Torres-Ruiz M, de Alba Gonzalez M, Cañas Portilla AI, Coronel R, Liste I, González-Caballero MC. Effects of nanomolar methylmercury on developing human neural stem cells and zebrafish Embryo. Food Chem Toxicol 2024; 188:114684. [PMID: 38663761 DOI: 10.1016/j.fct.2024.114684] [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: 02/27/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 04/29/2024]
Abstract
Exposure to mercury and its organic form methylmercury (MeHg), is of great concern for the developing nervous system. Despite available literature on MeHg neurotoxicity, there is still uncertainty about its mechanisms of action and the doses that trigger developmental effects. Our study combines two alternative methodologies, the human neural stem cells (NSC) and the zebrafish (ZF) embryo, to address the neurotoxic effects of early exposure to nanomolar concentrations of MeHg. Our results show linear or nonmonotonic (hormetic) responses depending on studied parameters. In ZF, we observed a hormetic response in locomotion and larval rotation, but a concentration-dependent response for sensory organ size and habituation. We also observed a possible delayed response as MeHg had greater effects on larval activity at 5 days than at 24 h. In NSC cells, some parameters show a clear dose dependence, such as increased apoptosis and differentiation to glial cells or decreased neuronal precursors; while others show a hormetic response: neuronal differentiation or cell proliferation. This study shows that the ZF model was more susceptible than NSC to MeHg neurotoxicity. The combination of different models has improved the understanding of the underlying mechanisms of toxicity and possible compensatory mechanisms at the cellular and organismal level.
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Affiliation(s)
- Mónica Torres-Ruiz
- Environmental Toxicology Unit, Centro Nacional de Sanidad Ambiental (CNSA), Instituto de Salud Carlos III (ISCIII), Ctra. Majadahonda-Pozuelo Km. 2,2., Majadahonda, Madrid, 28220, Spain.
| | - Mercedes de Alba Gonzalez
- Environmental Toxicology Unit, Centro Nacional de Sanidad Ambiental (CNSA), Instituto de Salud Carlos III (ISCIII), Ctra. Majadahonda-Pozuelo Km. 2,2., Majadahonda, Madrid, 28220, Spain
| | - Ana I Cañas Portilla
- Environmental Toxicology Unit, Centro Nacional de Sanidad Ambiental (CNSA), Instituto de Salud Carlos III (ISCIII), Ctra. Majadahonda-Pozuelo Km. 2,2., Majadahonda, Madrid, 28220, Spain
| | - Raquel Coronel
- Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain; Departamento de Biología de Sistemas, Facultad de Medicina y Ciencias de la Salud, Universidad de Alcalá, Madrid, Spain
| | - Isabel Liste
- Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Mª Carmen González-Caballero
- Environmental Toxicology Unit, Centro Nacional de Sanidad Ambiental (CNSA), Instituto de Salud Carlos III (ISCIII), Ctra. Majadahonda-Pozuelo Km. 2,2., Majadahonda, Madrid, 28220, Spain.
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Klus JK, Thurston SW, Myers GJ, Watson GE, Rand MD, Love TM, Yeates AJ, Mulhern MS, McSorley EM, Strain JJ, Shamlaye CF, van Wijngaarden E. Postnatal methylmercury exposure and neurodevelopmental outcomes at 7 years of age in the Seychelles Child Development Study Nutrition Cohort 2. Neurotoxicology 2023; 99:115-119. [PMID: 37832849 PMCID: PMC10842381 DOI: 10.1016/j.neuro.2023.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/02/2023] [Accepted: 10/05/2023] [Indexed: 10/15/2023]
Abstract
BACKGROUND Consumption of fish yields many nutritional benefits, but also results in exposure to methylmercury (MeHg). The developing brain is known to be particularly susceptible to MeHg toxicity in high doses. However, the potential impact of low-level environmental exposure from fish consumption on children's neurodevelopment remains unclear. METHODS We investigated postnatal MeHg exposure at 7 years and its association with a battery of 17 neurodevelopmental outcomes in a subset of children (n = 376) from 1535 enrolled mother-child pairs in Nutrition Cohort 2 of the Seychelles Child Development Study (SCDS NC2). Each outcome was modeled in relation to postnatal MeHg exposure using linear regression, adjusting for prenatal MeHg exposure, levels of maternal polyunsaturated fatty acids (PUFA), and several other covariates known to be associated with neurodevelopmental outcomes. RESULTS Median postnatal MeHg exposure at 7 years was 2.5 ppm, while the median prenatal MeHg exposure was 3.5 ppm. We found no statistically significant associations between postnatal MeHg exposure and any of the 17 neurodevelopmental outcomes after adjusting for prenatal MeHg exposure and other covariates. CONCLUSIONS These findings are consistent with previous cross-sectional analyses of the SCDS Main Cohort. Continued follow-up of the entire NC2 cohort at later ages with repeated exposure measures is needed to further confirm these findings.
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Affiliation(s)
- Jonathan K Klus
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Sally W Thurston
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Gary J Myers
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Gene E Watson
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Matthew D Rand
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Tanzy M Love
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Alison J Yeates
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland, UK
| | - Maria S Mulhern
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland, UK
| | - Emeir M McSorley
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland, UK
| | - J J Strain
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland, UK
| | | | - Edwin van Wijngaarden
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA.
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Nakamura M, Tatsuta N, Murata K, Nakai K, Iwata T, Otobe T, Sakamoto M, Yamamoto M, Itatani M, Miura Y, Koriyama C. Neurodevelopmental associations of prenatal and postnatal methylmercury exposure among first-grade children in the Kinan region, Japan. ENVIRONMENTAL RESEARCH 2023; 235:116688. [PMID: 37467938 DOI: 10.1016/j.envres.2023.116688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/14/2023] [Accepted: 07/15/2023] [Indexed: 07/21/2023]
Abstract
The most severe effects of methylmercury (MeHg) exposure during child development are thought to result from exposure during fetal life and childhood. However, comparing the neurodevelopmental effects of prenatal and postnatal MeHg exposure (PreMeHg and PostMeHg, respectively) remains unclear. We aimed to investigate the associations between neurodevelopmental indicators and PreMeHg or PostMeHg. The participants were 134 children in the first grade of elementary schools aged 7-8 years from the Kinan region, an area with high consumption of MeHg-rich whales and tunas in Japan. We measured MeHg levels in preserved umbilical cord tissues and total mercury (T-Hg) levels in children's hair to estimate PreMeHg and PostMeHg levels, respectively. Neuropsychological (intelligence quotient testing and Boston Naming Test) and neurophysiological (brainstem auditory evoked potential [BAEP], visual evoked potential [VEP], and color vision tests) studies were performed to evaluate the neurodevelopmental status. Multiple regression analyses were conducted according to sex. The geometric mean MeHg levels in preserved umbilical cord tissues and T-Hg levels in children's hair were 0.11 μg/g and 2.94 μg/g, respectively. Neither PreMeHg nor PostMeHg was related to neuropsychological indicators. Some associations between MeHg exposure and neurophysiological results were observed only in boys. N145 latency in VEPs was significantly prolonged with increasing PreMeHg (β: 12.01, 95% confidence interval [CI]: 0.648, 23.38). The III-V interpeak intervals in BAEP were significantly prolonged with increasing PreMeHg or PostMeHg (β [95% CI]: 0.142 [0.041, 0.243] and 0.159 [0.052, 0.265], respectively). After adjusting for PreMeHg, the association between PostMeHg and BAEP latencies disappeared. In conclusion, the latency in the auditory and visual pathways was significantly prolonged with increasing PreMeHg in boys. These findings suggest that male fetuses may be more susceptible to MeHg exposure.
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Affiliation(s)
- Masaaki Nakamura
- Department of Clinical Medicine, National Institute for Minamata Disease, 4058-18 Hama, Minamata City, Kumamoto, 867-0008, Japan.
| | - Nozomi Tatsuta
- Development and Environmental Medicine, Tohoku University Graduate School of Medicine, Sendai City, Miyagi, 980-8575, Japan.
| | - Katsuyuki Murata
- Department of Environmental Health Sciences, Akita University Graduate School of Medicine, 1-1 Hondo, Akita City, Akita, 010-8543, Japan.
| | - Kunihiko Nakai
- Development and Environmental Medicine, Tohoku University Graduate School of Medicine, Sendai City, Miyagi, 980-8575, Japan.
| | - Toyoto Iwata
- Department of Environmental Health Sciences, Akita University Graduate School of Medicine, 1-1 Hondo, Akita City, Akita, 010-8543, Japan.
| | - Takayuki Otobe
- Department of Child Education, Jin-ai University, Echizen City, Fukui, 910-0124, Japan.
| | - Mineshi Sakamoto
- Department of Environment and Public Health, National Institute for Minamata Disease, 4058-18 Hama, Minamata City, Kumamoto, 867-0008, Japan.
| | - Megumi Yamamoto
- Department of Environment and Public Health, National Institute for Minamata Disease, 4058-18 Hama, Minamata City, Kumamoto, 867-0008, Japan.
| | - Mina Itatani
- Department of Clinical Medicine, National Institute for Minamata Disease, 4058-18 Hama, Minamata City, Kumamoto, 867-0008, Japan.
| | - Yoko Miura
- Department of Clinical Medicine, National Institute for Minamata Disease, 4058-18 Hama, Minamata City, Kumamoto, 867-0008, Japan.
| | - Chihaya Koriyama
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.
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4
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Sakamoto M, Haraguchi K, Tatsuta N, Marumoto M, Yamamoto M, Nakamura M. Breast milk contribution to tissue mercury levels in rat pups examined by cross-fostering at birth. ENVIRONMENTAL RESEARCH 2022; 208:112772. [PMID: 35063428 DOI: 10.1016/j.envres.2022.112772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/13/2022] [Accepted: 01/13/2022] [Indexed: 06/14/2023]
Abstract
The developing perinatal brain is vulnerable to methylmercury (MeHg) exposure. The contribution of breast milk to tissue MeHg levels in offspring is a significant public health concern because breast milk contains a certain amount of MeHg. Here, the contribution of MeHg transferred via breast milk to the Hg levels in the tissues of pups (Wistar rats) was investigated. Mated maternal rats were fed a MeHg (2 ppm)-supplemented or a control diet during pregnancy. Following parturition, male neonates from each group were cross-fostered between exposed or control dams, and they were further raised by dams fed a MeHg-supplemented diet or a control diet during lactation. Consequently, we evaluated three pup groups, which were raised by dams exposed to MeHg during pregnancy (P pups), lactation (L pups), or pregnancy and lactation (PL pups). Total mercury (THg) concentrations in the tissues of the offspring were measured at birth (postnatal day 0 [PD0]), during lactation (PD6, PD12, and PD19), and after weaning (PD29 and PD36). Blood and brain THg levels in the P and PL pups declined dramatically during lactation, however, there were no considerable differences between the two groups at PD6 and PD12. In contrast, blood and brain THg levels in the L pups increased slightly during lactation. The increase in the THg levels in the blood and brain of L pups at PD12 were approximately 3.3% and 1.5%, respectively, compared to the corresponding THg levels in the neonates in the P and PL groups. Our results suggest that if the MeHg exposure level during pregnancy is not high enough to cause neuronal development defects in the fetus, the exposure via breast milk is not a significant concern.
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Affiliation(s)
- Mineshi Sakamoto
- National Institute for Minamata Disease, Minamata, Kumamoto, 867-0008, Japan.
| | - Koichi Haraguchi
- National Institute for Minamata Disease, Minamata, Kumamoto, 867-0008, Japan
| | - Nozomi Tatsuta
- Tohoku University School of Medicine, Sendai, 880-2112, Japan
| | - Masumi Marumoto
- National Institute for Minamata Disease, Minamata, Kumamoto, 867-0008, Japan
| | - Megumi Yamamoto
- National Institute for Minamata Disease, Minamata, Kumamoto, 867-0008, Japan
| | - Masaaki Nakamura
- National Institute for Minamata Disease, Minamata, Kumamoto, 867-0008, Japan
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Carstens KE, Carpenter AF, Martin MM, Harrill JA, Shafer TJ, Paul Friedman K. OUP accepted manuscript. Toxicol Sci 2022; 187:62-79. [PMID: 35172012 PMCID: PMC9421662 DOI: 10.1093/toxsci/kfac018] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In vivo developmental neurotoxicity (DNT) testing is resource intensive and lacks information on cellular processes affected by chemicals. To address this, DNT new approach methodologies (NAMs) are being evaluated, including: the microelectrode array neuronal network formation assay; and high-content imaging to evaluate proliferation, apoptosis, neurite outgrowth, and synaptogenesis. This work addresses 3 hypotheses: (1) a broad screening battery provides a sensitive marker of DNT bioactivity; (2) selective bioactivity (occurring at noncytotoxic concentrations) may indicate functional processes disrupted; and, (3) a subset of endpoints may optimally classify chemicals with in vivo evidence for DNT. The dataset was comprised of 92 chemicals screened in all 57 assay endpoints sourced from publicly available data, including a set of DNT NAM evaluation chemicals with putative positives (53) and negatives (13). The DNT NAM battery provides a sensitive marker of DNT bioactivity, particularly in cytotoxicity and network connectivity parameters. Hierarchical clustering suggested potency (including cytotoxicity) was important for classifying positive chemicals with high sensitivity (93%) but failed to distinguish patterns of disrupted functional processes. In contrast, clustering of selective values revealed informative patterns of differential activity but demonstrated lower sensitivity (74%). The false negatives were associated with several limitations, such as the maximal concentration tested or gaps in the biology captured by the current battery. This work demonstrates that this multi-dimensional assay suite provides a sensitive biomarker for DNT bioactivity, with selective activity providing possible insight into specific functional processes affected by chemical exposure and a basis for further research.
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Affiliation(s)
- Kelly E Carstens
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, USA
| | - Amy F Carpenter
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, USA
| | - Melissa M Martin
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | - Joshua A Harrill
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | - Timothy J Shafer
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | - Katie Paul Friedman
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
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6
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Diana Neely M, Xie S, Prince LM, Kim H, Tukker AM, Aschner M, Thimmapuram J, Bowman AB. Single cell RNA sequencing detects persistent cell type- and methylmercury exposure paradigm-specific effects in a human cortical neurodevelopmental model. Food Chem Toxicol 2021; 154:112288. [PMID: 34089799 DOI: 10.1016/j.fct.2021.112288] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/14/2021] [Accepted: 05/15/2021] [Indexed: 12/13/2022]
Abstract
The developing human brain is uniquely vulnerable to methylmercury (MeHg) resulting in lasting effects especially in developing cortical structures. Here we assess by single-cell RNA sequencing (scRNAseq) persistent effects of developmental MeHg exposure in a differentiating cortical human-induced pluripotent stem cell (hiPSC) model which we exposed to in vivo relevant and non-cytotoxic MeHg (0.1 and 1.0 μM) concentrations. The cultures were exposed continuously for 6 days either once only during days 4-10, a stage representative of neural epithelial- and radial glia cells, or twice on days 4-10 and days 14-20, a somewhat later stage which includes intermediate precursors and early postmitotic neurons. After the completion of MeHg exposure the cultures were differentiated further until day 38 and then assessed for persistent MeHg-induced effects by scRNAseq. We report subtle, but significant changes in the population size of different cortical cell types/stages and cell cycle. We also observe MeHg-dependent differential gene expression and altered biological processes as determined by Gene Ontology analysis. Our data demonstrate that MeHg results in changes in gene expression in human developing cortical neurons that manifest well after cessation of exposure and that these changes are cell type-, developmental stage-, and exposure paradigm-specific.
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Affiliation(s)
- M Diana Neely
- Dept of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Shaojun Xie
- Bioinformatics Core, Purdue University, West Lafayette, IN, USA
| | - Lisa M Prince
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
| | - Hyunjin Kim
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
| | - Anke M Tukker
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
| | - Michael Aschner
- Dept of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | | | - Aaron B Bowman
- Dept of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA; School of Health Sciences, Purdue University, West Lafayette, IN, USA.
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Vasistha NA, Khodosevich K. The impact of (ab)normal maternal environment on cortical development. Prog Neurobiol 2021; 202:102054. [PMID: 33905709 DOI: 10.1016/j.pneurobio.2021.102054] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/01/2021] [Accepted: 04/20/2021] [Indexed: 12/24/2022]
Abstract
The cortex in the mammalian brain is the most complex brain region that integrates sensory information and coordinates motor and cognitive processes. To perform such functions, the cortex contains multiple subtypes of neurons that are generated during embryogenesis. Newly born neurons migrate to their proper location in the cortex, grow axons and dendrites, and form neuronal circuits. These developmental processes in the fetal brain are regulated to a large extent by a great variety of factors derived from the mother - starting from simple nutrients as building blocks and ending with hormones. Thus, when the normal maternal environment is disturbed due to maternal infection, stress, malnutrition, or toxic substances, it might have a profound impact on cortical development and the offspring can develop a variety of neurodevelopmental disorders. Here we first describe the major developmental processes which generate neuronal diversity in the cortex. We then review our knowledge of how most common maternal insults affect cortical development, perturb neuronal circuits, and lead to neurodevelopmental disorders. We further present a concept of selective vulnerability of cortical neuronal subtypes to maternal-derived insults, where the vulnerability of cortical neurons and their progenitors to an insult depends on the time (developmental period), place (location in the developing brain), and type (unique features of a cell type and an insult). Finally, we provide evidence for the existence of selective vulnerability during cortical development and identify the most vulnerable neuronal types, stages of differentiation, and developmental time for major maternal-derived insults.
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Affiliation(s)
- Navneet A Vasistha
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
| | - Konstantin Khodosevich
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
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8
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Werder EJ, Engel LS, Curry MD, Sandler DP. Selenium modifies associations between multiple metals and neurologic symptoms in Gulf states residents. Environ Epidemiol 2020; 4:e115. [PMID: 33336134 PMCID: PMC7727467 DOI: 10.1097/ee9.0000000000000115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/23/2020] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Metals have been shown to have a wide range of neurologic effects across the life course, but most studies consider neurodevelopment or neurodegenerative diseases in older adults. We investigated exposure to metals during adulthood in association with subclinical neurologic endpoints, considering the metals individually and as a mixture, and potential interactions among exposures. METHODS We measured blood levels of cadmium, lead, mercury, manganese, and selenium in 1007 Gulf state residents and estimated cross-sectional associations between ranked levels of blood metals and the presence of self-reported neurologic symptoms. Single pollutant models were mutually adjusted for other metals and we used quantile g-computation to evaluate associations with exposure to the combined mixture. In stratified analyses, we assessed heterogeneity by smoking and blood selenium. RESULTS The highest quartile of cadmium was associated with a higher prevalence of central nervous system symptoms (prevalence ratio [PR] = 1.50; 95% confidence interval [CI] = 1.13, 1.99), with stronger associations among nonsmokers (PR = 1.63; 95% CI = 1.11, 2.38) and those with low selenium (PR = 2.29, 95% CI = 1.50, 3.49). Selenium also modified associations between lead and peripheral nervous system symptoms, with increased symptoms in the low selenium group at all quartiles of exposure (P-trend = 0.07). Conversely, those with the highest co-exposure to mercury and selenium had reduced neurologic symptoms (PR = 0.73, 95% CI = 0.55, 0.96). Results of the mixture analysis were consistent with single chemical results. CONCLUSIONS Cadmium exhibited the most consistent relationship with increased neurologic symptoms, though lead was an important exposure in subgroup analyses. Selenium may modify subclinical neurotoxic effects of metals at non-occupational levels in adults.
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Affiliation(s)
- Emily J. Werder
- Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, North Carolina
| | - Lawrence S. Engel
- Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, North Carolina
- Department of Epidemiology, UNC Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina
| | | | - Dale P. Sandler
- Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, North Carolina
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9
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Sakamoto M, Kakita A, Sakai K, Kameo S, Yamamoto M, Nakamura M. Methylmercury exposure during the vulnerable window of the cerebrum in postnatal developing rats. ENVIRONMENTAL RESEARCH 2020; 188:109776. [PMID: 32592939 DOI: 10.1016/j.envres.2020.109776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/02/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
The developing brain is known to be sensitive to the toxic effects of methylmercury (MeHg). The effects of toxic levels of MeHg exposure during the most seemingly vulnerable window of the cerebrum are not well studied. In this study, we aimed to examine the specific effects of toxic levels of MeHg on neurobehavior, neurodegeneration, and selenoenzyme activity in the cerebrum of infant rats. Male Wistar rats (n = 8/group) were orally treated with MeHg at an acute toxic dose (8 mg Hg/kg/day) for 10 consecutive days starting on postnatal day 14 (P14). The MeHg-exposed rats showed a significant reduction in body weight after day 8 and severe neurological symptoms similar to dystonia on day 12 (P25). Motor coordination deficits determined using the rotarod performance test and short-term memory impairment determined using the Y-maze task were observed in the MeHg-exposed rats on day 11 (P24). The MeHg-exposed rats sacrificed on day 12 showed severe cerebral neuronal degeneration, reactive astrocytosis, and TUNEL-positive apoptotic nuclei, with the cerebral Hg concentration of 15.0 ± 1.6 μg/g. Furthermore, the activities of glutathione peroxidase and thioredoxin reductase in the cerebrum in MeHg-exposed rats were lower than those in control. These results indicate that MeHg exposure to infant rats will be useful to predict the effects of MeHg at the cerebral growth spurt in humans.
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Affiliation(s)
| | - Akiyoshi Kakita
- Brain Research Institute, Niigata University, Niigata, Japan
| | - Kazuo Sakai
- Japan Institute for the Control of Aging, Nikken SEIL Co., Ltd., Japan
| | - Satomi Kameo
- Department of Public Health, Graduate School of Medicine, Gunma University, Japan; Department of Nutrition, Koshien University, Hyogo, Japan
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10
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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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11
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Effects of Gintonin-Enriched Fraction on Methylmercury-Induced Neurotoxicity and Organ Methylmercury Elimination. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17030838. [PMID: 32013120 PMCID: PMC7038146 DOI: 10.3390/ijerph17030838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/18/2020] [Accepted: 01/24/2020] [Indexed: 01/09/2023]
Abstract
Gintonin is a newly discovered ingredient of ginseng and plays an exogenous ligand for G protein-coupled lysophosphatidic acid receptors. We previously showed that gintonin exhibits diverse effects from neurotransmitter release to improvement of Alzheimer’s disease-related cognitive dysfunctions. However, previous studies did not show whether gintonin has protective effects against environmental heavy metal. We investigated the effects of gintonin-enriched fraction (GEF) on methylmercury (MeHg)-induced neurotoxicity and learning and memory dysfunction and on organ MeHg elimination. Using hippocampal neural progenitor cells (hNPCs) and mice we examined the effects of GEF on MeHg-induced hippocampal NPC neurotoxicity, on formation of reactive oxygen species (ROS), and on in vivo learning and memory functions after acute MeHg exposure. Treatment of GEF to hNPCs attenuated MeHg-induced neurotoxicity with concentration- and time-dependent manner. GEF treatment inhibited MeHg- and ROS inducer-induced ROS formations. Long-term treatment of GEF also improved MeHg-induced learning and memory dysfunctions. Oral administration of GEF decreased the concentrations of MeHg in blood, brain, liver, and kidney. This is the first report that GEF attenuated MeHg-induced in vitro and in vivo neurotoxicities through LPA (lysophosphatidic acids) receptor-independent manner and increased organ MeHg elimination. GEF-mediated neuroprotection might achieve via inhibition of ROS formation and facilitation of MeHg elimination from body.
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12
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Ke T, Gonçalves FM, Gonçalves CL, Dos Santos AA, Rocha JBT, Farina M, Skalny A, Tsatsakis A, Bowman AB, Aschner M. Post-translational modifications in MeHg-induced neurotoxicity. Biochim Biophys Acta Mol Basis Dis 2018; 1865:2068-2081. [PMID: 30385410 DOI: 10.1016/j.bbadis.2018.10.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 10/16/2018] [Accepted: 10/19/2018] [Indexed: 12/29/2022]
Abstract
Mercury (Hg) exposure remains a major public health concern due to its widespread distribution in the environment. Organic mercurials, such as MeHg, have been extensively investigated especially because of their congenital effects. In this context, studies on the molecular mechanism of MeHg-induced neurotoxicity are pivotal to the understanding of its toxic effects and the development of preventive measures. Post-translational modifications (PTMs) of proteins, such as phosphorylation, ubiquitination, and acetylation are essential for the proper function of proteins and play important roles in the regulation of cellular homeostasis. The rapid and transient nature of many PTMs allows efficient signal transduction in response to stress. This review summarizes the current knowledge of PTMs in MeHg-induced neurotoxicity, including the most commonly PTMs, as well as PTMs induced by oxidative stress and PTMs of antioxidant proteins. Though PTMs represent an important molecular mechanism for maintaining cellular homeostasis and are involved in the neurotoxic effects of MeHg, we are far from understanding the complete picture on their role, and further research is warranted to increase our knowledge of PTMs in MeHg-induced neurotoxicity.
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Affiliation(s)
- Tao Ke
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, United States.
| | - Filipe Marques Gonçalves
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Cinara Ludvig Gonçalves
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | | | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105900 Santa Maria, RS, Brazil
| | - Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, 88040900 Florianópolis, SC, Brazil
| | - Anatoly Skalny
- Yaroslavl State University, Sovetskaya St., 14, Yaroslavl 150000, Russia; Peoples' Friendship University of Russia (RUDN University), Miklukho-Maklaya St., 6, Moscow 105064, Russia; Orenburg State University, Pobedy Ave., 13, Orenburg 460352, Russia
| | - Aristidis Tsatsakis
- Center of Toxicology Science & Research, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Aaron B Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN, United States.
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, United States.
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13
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Bal-Price A, Hogberg HT, Crofton KM, Daneshian M, FitzGerald RE, Fritsche E, Heinonen T, Hougaard Bennekou S, Klima S, Piersma AH, Sachana M, Shafer TJ, Terron A, Monnet-Tschudi F, Viviani B, Waldmann T, Westerink RHS, Wilks MF, Witters H, Zurich MG, Leist M. Recommendation on test readiness criteria for new approach methods in toxicology: Exemplified for developmental neurotoxicity. ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2018; 35:306-352. [PMID: 29485663 DOI: 10.14573/altex.1712081] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 01/29/2018] [Indexed: 01/06/2023]
Abstract
Multiple non-animal-based test methods have never been formally validated. In order to use such new approach methods (NAMs) in a regulatory context, criteria to define their readiness are necessary. The field of developmental neurotoxicity (DNT) testing is used to exemplify the application of readiness criteria. The costs and number of untested chemicals are overwhelming for in vivo DNT testing. Thus, there is a need for inexpensive, high-throughput NAMs, to obtain initial information on potential hazards, and to allow prioritization for further testing. A background on the regulatory and scientific status of DNT testing is provided showing different types of test readiness levels, depending on the intended use of data from NAMs. Readiness criteria, compiled during a stakeholder workshop, uniting scientists from academia, industry and regulatory authorities are presented. An important step beyond the listing of criteria, was the suggestion for a preliminary scoring scheme. On this basis a (semi)-quantitative analysis process was assembled on test readiness of 17 NAMs with respect to various uses (e.g. prioritization/screening, risk assessment). The scoring results suggest that several assays are currently at high readiness levels. Therefore, suggestions are made on how DNT NAMs may be assembled into an integrated approach to testing and assessment (IATA). In parallel, the testing state in these assays was compiled for more than 1000 compounds. Finally, a vision is presented on how further NAM development may be guided by knowledge of signaling pathways necessary for brain development, DNT pathophysiology, and relevant adverse outcome pathways (AOP).
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Affiliation(s)
- Anna Bal-Price
- European Commission, Joint Research Centre (EC JRC), Ispra (VA), Italy
| | - Helena T Hogberg
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins University, Baltimore, MD, USA
| | - Kevin M Crofton
- National Centre for Computational Toxicology, US EPA, RTP, Washington, NC, USA
| | - Mardas Daneshian
- Center for Alternatives to Animal Testing, CAAT-Europe, University of Konstanz, Konstanz, Germany
| | - Rex E FitzGerald
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland
| | - Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine & Heinrich-Heine-University, Düsseldorf, Germany
| | - Tuula Heinonen
- Finnish Centre for Alternative Methods (FICAM), University of Tampere, Tampere, Finland
| | | | - Stefanie Klima
- In vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Aldert H Piersma
- RIVM, National Institute for Public Health and the Environment, Bilthoven, and Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Magdalini Sachana
- Organisation for Economic Co-operation and Development (OECD), Paris, France
| | - Timothy J Shafer
- National Centre for Computational Toxicology, US EPA, RTP, Washington, NC, USA
| | | | - Florianne Monnet-Tschudi
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland.,Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Barbara Viviani
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Italy
| | - Tanja Waldmann
- In vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Remco H S Westerink
- Neurotoxicology Research Group, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Martin F Wilks
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland
| | - Hilda Witters
- VITO, Flemish Institute for Technological Research, Unit Environmental Risk and Health, Mol, Belgium
| | - Marie-Gabrielle Zurich
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland.,Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Marcel Leist
- Center for Alternatives to Animal Testing, CAAT-Europe, University of Konstanz, Konstanz, Germany.,In vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
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14
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Sakamoto M, Chan HM, Domingo JL, Koriyama C, Murata K. Placental transfer and levels of mercury, selenium, vitamin E, and docosahexaenoic acid in maternal and umbilical cord blood. ENVIRONMENT INTERNATIONAL 2018; 111:309-315. [PMID: 29150340 DOI: 10.1016/j.envint.2017.11.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/27/2017] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
Methylmercury (MeHg) is a neurotoxicant known to affect the developing fetal brain as a sensitive target organ. As most mercury (Hg) in blood is MeHg, total mercury (THg) levels in blood are used to estimate the body burden of MeHg. The nutrients selenium (Se), vitamin E, and docosahexaenoic acid (DHA) are protective against MeHg toxicity. We compared maternal and cord blood concentrations of biochemical substances, THg and Se, vitamin E, DHA, and other elements, fatty acids, and amino acids in 54 Japanese mother-newborn pairs to elucidate the fetal risk of MeHg toxicity. Cord blood had higher hematocrit and amino acid values and lower concentrations of lipid components, including fatty acids compared with maternal blood. THg levels in cord blood (7.26ng/g) were 1.9 times higher than levels in maternal blood (3.79ng/g). Se concentrations in cord blood (176ng/g) were slightly higher than concentrations in maternal blood (156ng/g). Levels of vitamin E (0.31mg/dL) and DHA (58.8μg/mL) in cord blood were much lower than levels in maternal blood (1.38mg/dL and 147μg/mL, respectively). The ratios of Se/THg, vitamin E/THg, and DHA/THg in cord blood were lower than ratios in maternal blood. These results suggest that fetuses are at higher risk to MeHg toxicity.
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Affiliation(s)
- Mineshi Sakamoto
- Environmental Health Section, Department of Environmental Science and Epidemiology, National Institute for Minamata Disease, Minamata, Japan; Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
| | - Hing Man Chan
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - José L Domingo
- Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat "Rovira i Virgili", Reus, Spain
| | - Chihaya Koriyama
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Katsuyuki Murata
- Department of Environmental Health Sciences, Akita University Graduate School of Medicine, Akita, Japan
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15
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Uchikawa T, Kanno T, Maruyama I, Mori N, Yasutake A, Ishii Y, Yamada H. Demethylation of methylmercury and the enhanced production of formaldehyde in mouse liver. J Toxicol Sci 2017; 41:479-87. [PMID: 27432234 DOI: 10.2131/jts.41.479] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Methylmercury (MeHg) is gradually changed to inorganic Hg after demethylation in animal tissues, and a selective quantification of inorganic Hg in the tissues is necessary to detect the reaction. We detected inorganic Hg formation in liver and kidney of mouse as early as 24 hr after MeHg injection. As an example of biological demethylation, the cytochrome P450 (P450)-mediated N-demethylation of drugs has been well documented, and formaldehyde was detected as a reaction product. Here we incubated mouse liver homogenate with added MeHg and observed a dose-dependent production of formaldehyde, as well as inorganic Hg formation. Since the amount of formaldehyde was approx. 500 times higher than that of the inorganic Hg that formed, the formaldehyde production would be stimulated by inorganic Hg formed from MeHg. We observed that inorganic Hg caused formaldehyde production, and it was enhanced by L-methionine and sarcosine. Thus, some biomolecules with S-methyl and N-methyl groups may function as methyl donors in the reaction. Using subcellular fractions of mouse liver, we observed that microsomal P450 did not participate in the demethylation of MeHg, but the greatest activity was located in the mitochondria-rich fraction. The addition of superoxide anion in the reaction mixture significantly enhanced the formaldehyde production, whereas Mn-superoxide dismutase depressed the reaction. Our present findings demonstrated that inorganic Hg formed by MeHg demethylation in mouse liver stimulated the endogenous formaldehyde production, and we observed that MeHg demethylation could be estimated by a formaldehyde analysis. Our results also suggested that superoxide anion is involved in the reaction.
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Affiliation(s)
- Takuya Uchikawa
- Graduate School of Pharmaceutical Sciences, Kyushu University
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16
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Assessment of neuroanatomical and behavioural effects of in ovo methylmercury exposure in zebra finches ( Taeniopygia guttata ). Neurotoxicology 2017; 59:33-39. [DOI: 10.1016/j.neuro.2017.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 01/03/2017] [Accepted: 01/04/2017] [Indexed: 12/25/2022]
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17
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Yoshida S, Matsumoto S, Kanchika T, Hagiwara T, Minami T. The organic mercury compounds, methylmercury and ethylmercury, inhibited ciliary movement of ventricular ependymal cells in the mouse brain around the concentrations reported for human poisoning. Neurotoxicology 2016; 57:69-74. [DOI: 10.1016/j.neuro.2016.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/15/2016] [Indexed: 11/29/2022]
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18
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Antunes Dos Santos A, Appel Hort M, Culbreth M, López-Granero C, Farina M, Rocha JBT, Aschner M. Methylmercury and brain development: A review of recent literature. J Trace Elem Med Biol 2016; 38:99-107. [PMID: 26987277 PMCID: PMC5011031 DOI: 10.1016/j.jtemb.2016.03.001] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 03/02/2016] [Indexed: 02/02/2023]
Abstract
Methylmercury (MeHg) is a potent environmental pollutant, which elicits significant toxicity in humans. The central nervous system (CNS) is the primary target of toxicity, and is particularly vulnerable during development. Maternal exposure to MeHg via consumption of fish and seafood can have irreversible effects on the neurobehavioral development of children, even in the absence of symptoms in the mother. It is well documented that developmental MeHg exposure may lead to neurological alterations, including cognitive and motor dysfunction. The neurotoxic effects of MeHg on the developing brain have been extensively studied. The mechanism of toxicity, however, is not fully understood. No single process can explain the multitude of effects observed in MeHg-induced neurotoxicity. This review summarizes the most current knowledge on the effects of MeHg during nervous system development considering both, in vitro and in vivo experimental models. Considerable attention was directed towards the role of glutamate and calcium dyshomeostasis, mitochondrial dysfunction, as well as the effects of MeHg on cytoskeletal components/regulators.
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Affiliation(s)
| | - Mariana Appel Hort
- Institute of Biological Sciences, Federal University of Rio Grande, Campus Carreiros, Rio Grande do Sul, Brazil
| | - Megan Culbreth
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Caridad López-Granero
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Marcelo Farina
- Department of Biochemistry, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil
| | - Joao B T Rocha
- Department of Biochemistry, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA.
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19
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Karri V, Schuhmacher M, Kumar V. Heavy metals (Pb, Cd, As and MeHg) as risk factors for cognitive dysfunction: A general review of metal mixture mechanism in brain. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 48:203-213. [PMID: 27816841 DOI: 10.1016/j.etap.2016.09.016] [Citation(s) in RCA: 273] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/21/2016] [Accepted: 09/24/2016] [Indexed: 05/22/2023]
Abstract
Human exposure to toxic heavy metals is a global challenge. Concurrent exposure of heavy metals, such as lead (Pb), cadmium (Cd), arsenic (As) and methylmercury (MeHg) are particularly important due to their long lasting effects on the brain. The exact toxicological mechanisms invoked by exposure to mixtures of the metals Pb, Cd, As and MeHg are still unclear, however they share many common pathways for causing cognitive dysfunction. The combination of metals may produce additive/synergetic effects due to their common binding affinity with NMDA receptor (Pb, As, MeHg), Na+ - K+ ATP-ase pump (Cd, MeHg), biological Ca+2 (Pb, Cd, MeHg), Glu neurotransmitter (Pb, MeHg), which can lead to imbalance between the pro-oxidant elements (ROS) and the antioxidants (reducing elements). In this process, ROS dominates the antioxidants factors such as GPx, GS, GSH, MT-III, Catalase, SOD, BDNF, and CERB, and finally leads to cognitive dysfunction. The present review illustrates an account of the current knowledge about the individual metal induced cognitive dysfunction mechanisms and analyse common Mode of Actions (MOAs) of quaternary metal mixture (Pb, Cd, As, MeHg). This review aims to help advancement in mixture toxicology and development of next generation predictive model (such as PBPK/PD) combining both kinetic and dynamic interactions of metals.
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Affiliation(s)
- Venkatanaidu Karri
- Center of Environmental Food and Toxicological Technology (TecnATox), Departament d'Enginyeria Química, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Marta Schuhmacher
- Center of Environmental Food and Toxicological Technology (TecnATox), Departament d'Enginyeria Química, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Vikas Kumar
- Center of Environmental Food and Toxicological Technology (TecnATox), Departament d'Enginyeria Química, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain.
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20
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Koning IV, Tielemans MJ, Hoebeek FE, Ecury-Goossen GM, Reiss IKM, Steegers-Theunissen RPM, Dudink J. Impacts on prenatal development of the human cerebellum: a systematic review. J Matern Fetal Neonatal Med 2016; 30:2461-2468. [PMID: 27806674 DOI: 10.1080/14767058.2016.1253060] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE The cerebellum is essential for normal neurodevelopment and is particularly susceptible for intra-uterine disruptions. Although some causal prenatal exposures have been identified, the origin of neurodevelopmental disorders remains mostly unclear. Therefore, a systematic literature search was conducted to provide an overview of parental environmental exposures and intrinsic factors influencing prenatal cerebellar growth and development in humans. MATERIALS AND METHODS The literature search was limited to human studies in the English language and was conducted in Embase, Medline, Cochrane, Web of Science, Pubmed and GoogleScholar. Eligible studies were selected by three independent reviewers and study quality was scored by two independent reviewers. RESULTS The search yielded 3872 articles. We found 15 eligible studies reporting associations between cerebellar development and maternal smoking (4), use of alcohol (3), in vitro fertilization mediums (1), mercury (1), mifepristone (2), aminopropionitriles (1), ethnicity (2) and cortisol levels (1). No studies reported on paternal factors. CONCLUSIONS Current literature on associations between parental environmental exposures, intrinsic factors and human cerebellar development is scarce. Yet, this systematic review provided an essential overview of human studies demonstrating the vulnerability of the cerebellum to the intra-uterine environment.
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Affiliation(s)
- Irene V Koning
- a Department of Obstetrics and Gynecology , Erasmus MC University Medical Center , Rotterdam , The Netherlands.,b Department of Pediatrics , Subdivision of Neonatology, Sophia Children's Hospital , Rotterdam , The Netherlands
| | | | - Freek E Hoebeek
- d Department of Neuroscience , Erasmus MC University Medical Center , Rotterdam , The Netherlands , and
| | - Ginette M Ecury-Goossen
- b Department of Pediatrics , Subdivision of Neonatology, Sophia Children's Hospital , Rotterdam , The Netherlands
| | - Irwin K M Reiss
- b Department of Pediatrics , Subdivision of Neonatology, Sophia Children's Hospital , Rotterdam , The Netherlands
| | - Regine P M Steegers-Theunissen
- a Department of Obstetrics and Gynecology , Erasmus MC University Medical Center , Rotterdam , The Netherlands.,b Department of Pediatrics , Subdivision of Neonatology, Sophia Children's Hospital , Rotterdam , The Netherlands
| | - Jeroen Dudink
- b Department of Pediatrics , Subdivision of Neonatology, Sophia Children's Hospital , Rotterdam , The Netherlands.,e Department of Neonatology , Wilhelmina Children's Hospital, University Medical Center Utrecht , Utrecht , The Netherlands
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Cope ZA, Powell SB, Young JW. Modeling neurodevelopmental cognitive deficits in tasks with cross-species translational validity. GENES BRAIN AND BEHAVIOR 2016; 15:27-44. [PMID: 26667374 DOI: 10.1111/gbb.12268] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/14/2015] [Accepted: 10/27/2015] [Indexed: 12/24/2022]
Abstract
Numerous psychiatric disorders whose cognitive dysfunction links to functional outcome have neurodevelopmental origins including schizophrenia, autism and bipolar disorder. Treatments are needed for these cognitive deficits, which require development using animal models. Models of neurodevelopmental disorders are as varied and diverse as the disorders themselves, recreating some but not all aspects of the disorder. This variety may in part underlie why purported procognitive treatments translated from these models have failed to restore functioning in the targeted patient populations. Further complications arise from environmental factors used in these models that can contribute to numerous disorders, perhaps only impacting specific domains, while diagnostic boundaries define individual disorders, limiting translational efficacy. The Research Domain Criteria project seeks to 'develop new ways to classify mental disorders based on behavioral dimensions and neurobiological measures' in hopes of facilitating translational research by remaining agnostic toward diagnostic borders derived from clinical presentation in humans. Models could therefore recreate biosignatures of cognitive dysfunction irrespective of disease state. This review highlights work within the field of neurodevelopmental models of psychiatric disorders tested in cross-species translational cognitive paradigms that directly inform this newly developing research strategy. By expounding on this approach, the hopes are that a fuller understanding of each model may be attainable in terms of the cognitive profile elicited by each manipulation. Hence, conclusions may begin to be drawn on the nature of cognitive neuropathology on neurodevelopmental and other disorders, increasing the chances of procognitive treatment development for individuals affected in specific cognitive domains.
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Affiliation(s)
- Z A Cope
- Department of Psychiatry, University of California San Diego, La Jolla
| | - S B Powell
- Department of Psychiatry, University of California San Diego, La Jolla.,Research Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - J W Young
- Department of Psychiatry, University of California San Diego, La Jolla.,Research Service, VA San Diego Healthcare System, San Diego, CA, USA
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22
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Olivero-Verbel J, Carranza-Lopez L, Caballero-Gallardo K, Ripoll-Arboleda A, Muñoz-Sosa D. Human exposure and risk assessment associated with mercury pollution in the Caqueta River, Colombian Amazon. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:20761-20771. [PMID: 27475435 DOI: 10.1007/s11356-016-7255-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
Mercury (Hg) is a global contaminant posing severe risks to human health worldwide. The aim of this study was to assess the levels of total Hg (T-Hg) in human hair and fish in the Caqueta River, at the Colombian Amazon, as well as to determine fish consumption-based risks for T-Hg ingestion. T-Hg levels were measured using a direct mercury analyzer. The overall mean T-Hg level in hair for humans in the Caqueta River sample (n = 200) was 17.29 ± 0.61 μg/g (1.2 to 47.0 μg/g). Ninety-four percent of the individuals had hair T-Hg concentrations greater than the WHO threshold level (5 μg/g), and 79 % displayed levels higher than 10 μg/g. Average Hg concentrations in fish varied between 0.10-0.15 μg/g and 0.10-1.60 μg/g, for noncarnivorous and carnivorous species, respectively. Based on the maximum allowable fish consumption rate for adults, most carnivorous species should be avoided in the diet, as their target hazard quotient ranged from 2.96 up to 31.05, representing a risk for Hg-related health problems. In the light of existing evidence for elevated Hg levels in the indigenous population of the Colombian Amazon, carnivorous fish should be restricted as part of the diet, and breastfeeding should be reduced to protect children health. Most importantly, gold mining activities directly on rivers demand immediate attention from the national government to avoid extensive damage on the environment and human health.
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Affiliation(s)
- Jesus Olivero-Verbel
- Environmental and Computational Chemistry Group, School of Pharmaceutical Sciences, University of Cartagena, Zaragocilla Campus, Cartagena, 130014, Colombia.
| | - Liliana Carranza-Lopez
- Environmental and Computational Chemistry Group, School of Pharmaceutical Sciences, University of Cartagena, Zaragocilla Campus, Cartagena, 130014, Colombia
| | - Karina Caballero-Gallardo
- Environmental and Computational Chemistry Group, School of Pharmaceutical Sciences, University of Cartagena, Zaragocilla Campus, Cartagena, 130014, Colombia
| | - Adriana Ripoll-Arboleda
- Environmental and Computational Chemistry Group, School of Pharmaceutical Sciences, University of Cartagena, Zaragocilla Campus, Cartagena, 130014, Colombia
| | - Diego Muñoz-Sosa
- PNN Yaigojé Apaporis, National Parks of Colombia, Avenida Internacional 4-85, Leticia, Amazonas, Colombia
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23
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Pierozan P, Biasibetti H, Schmitz F, Ávila H, Fernandes CG, Pessoa-Pureur R, Wyse ATS. Neurotoxicity of Methylmercury in Isolated Astrocytes and Neurons: the Cytoskeleton as a Main Target. Mol Neurobiol 2016; 54:5752-5767. [DOI: 10.1007/s12035-016-0101-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/05/2016] [Indexed: 01/16/2023]
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Bellinger DC, Matthews-Bellinger JA, Kordas K. A developmental perspective on early-life exposure to neurotoxicants. ENVIRONMENT INTERNATIONAL 2016; 94:103-112. [PMID: 27235688 DOI: 10.1016/j.envint.2016.05.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/14/2016] [Accepted: 05/14/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND Studies of early-life neurotoxicant exposure have not been designed, analyzed, or interpreted in the context of a fully developmental perspective. OBJECTIVES The goal of this paper is to describe the key principles of a developmental perspective and to use examples from the literature to illustrate the relevance of these principles to early-life neurotoxicant exposures. METHODS Four principles are discussed: 1) the effects of early-life neurotoxicant exposure depend on a child's developmental context; 2) deficits caused by early-life exposure initiate developmental cascades that can lead to pathologies that differ from those observed initially; 3) early-life neurotoxicant exposure has intra-familial and intergenerational impacts; 4) the impacts of early-life neurotoxicant exposure influence a child's ability to respond to future insults. The first principle is supported by considerable evidence, but the other three have received much less attention. DISCUSSION Incorporating a developmental perspective in studies of early-life neurotoxicant exposures requires prospective collection of data on a larger array of covariates than usually considered, using analytical approaches that acknowledge the transactional processes between a child and the environment and the phenomenon of developmental cascades. CONCLUSION Consideration of early-life neurotoxicant exposure within a developmental perspective reveals that many issues remain to be explicated if we are to achieve a deep understanding of the societal health burden associated with early-life neurotoxicant exposures.
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Affiliation(s)
- David C Bellinger
- Department of Neurology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02112, USA; Department of Psychiatry, Harvard Medical School, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
| | - Julia A Matthews-Bellinger
- Department of Psychiatry, University of Massachusetts Medical School, Boston Psychoanalytic Society and Institute, 19 Fair Oaks Park, Needham, MA 02492, USA.
| | - Katarzyna Kordas
- Department of Epidemiology and Environmental Health, University at Buffalo, 270 Farber Hall, Buffalo, NY 14214, USA.
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Abstract
There is a growing interest in understanding the mechanisms that drive the developmental origins of health and disease, and the role of epigenetic regulation has risen to the forefront of these studies. In particular, the placenta may be a model organ to consider as a mediator of the impact of the environment on developmental programming of children's health, as this organ plays a critical role in directing development and regulating the fetal environment. Several recent studies have begun to examine how environmental toxicant exposures can impact the placental epigenome, focusing on studies of DNA methylation and microRNA expression. This review highlights several of these studies and emphasizes the potential the placenta may hold on the broader understanding of the impact of the intrauterine environment on long-term health.
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Affiliation(s)
- Carmen J Marsit
- Department of Pharmacology and Toxicology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
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Abstract
SIGNIFICANCE Mitochondria are structurally and biochemically diverse, even within a single type of cell. Protein complexes localized to the inner mitochondrial membrane synthesize ATP by coupling electron transport and oxidative phosphorylation. The organelles produce reactive oxygen species (ROS) from mitochondrial oxygen and ROS can, in turn, alter the function and expression of proteins used for aerobic respiration by post-translational and transcriptional regulation. RECENT ADVANCES New interest is emerging not only into the roles of mitochondria in disease development and progression but also as a target for environmental toxicants. CRITICAL ISSUES Dysregulation of respiration has been linked to cell death and is a major contributor to acute neuronal trauma, peripheral diseases, as well as chronic neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. FUTURE DIRECTIONS Here, we discuss the mechanisms underlying the sensitivity of the mitochondrial respiratory complexes to redox modulation, as well as examine the effects of environmental contaminants that have well-characterized mitochondrial toxicity. The contaminants discussed in this review are some of the most prevalent and potent environmental contaminants that have been linked to neurological dysfunction, altered cellular respiration, and oxidation.
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Affiliation(s)
- Samuel W Caito
- Department of Molecular Pharmacology, Albert Einstein College of Medicine , Bronx, New York
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine , Bronx, New York
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Rempel E, Hoelting L, Waldmann T, Balmer NV, Schildknecht S, Grinberg M, Das Gaspar JA, Shinde V, Stöber R, Marchan R, van Thriel C, Liebing J, Meisig J, Blüthgen N, Sachinidis A, Rahnenführer J, Hengstler JG, Leist M. A transcriptome-based classifier to identify developmental toxicants by stem cell testing: design, validation and optimization for histone deacetylase inhibitors. Arch Toxicol 2015; 89:1599-618. [PMID: 26272509 PMCID: PMC4551554 DOI: 10.1007/s00204-015-1573-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 07/22/2015] [Indexed: 12/17/2022]
Abstract
Test systems to identify developmental toxicants are urgently needed. A combination of human stem cell technology and transcriptome analysis was to provide a proof of concept that toxicants with a related mode of action can be identified and grouped for read-across. We chose a test system of developmental toxicity, related to the generation of neuroectoderm from pluripotent stem cells (UKN1), and exposed cells for 6 days to the histone deacetylase inhibitors (HDACi) valproic acid, trichostatin A, vorinostat, belinostat, panobinostat and entinostat. To provide insight into their toxic action, we identified HDACi consensus genes, assigned them to superordinate biological processes and mapped them to a human transcription factor network constructed from hundreds of transcriptome data sets. We also tested a heterogeneous group of ‘mercurials’ (methylmercury, thimerosal, mercury(II)chloride, mercury(II)bromide, 4-chloromercuribenzoic acid, phenylmercuric acid). Microarray data were compared at the highest non-cytotoxic concentration for all 12 toxicants. A support vector machine (SVM)-based classifier predicted all HDACi correctly. For validation, the classifier was applied to legacy data sets of HDACi, and for each exposure situation, the SVM predictions correlated with the developmental toxicity. Finally, optimization of the classifier based on 100 probe sets showed that eight genes (F2RL2, TFAP2B, EDNRA, FOXD3, SIX3, MT1E, ETS1 and LHX2) are sufficient to separate HDACi from mercurials. Our data demonstrate how human stem cells and transcriptome analysis can be combined for mechanistic grouping and prediction of toxicants. Extension of this concept to mechanisms beyond HDACi would allow prediction of human developmental toxicity hazard of unknown compounds with the UKN1 test system.
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Affiliation(s)
- Eugen Rempel
- Department of Statistics, TU Dortmund University, 44139, Dortmund, Germany
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Maccani JZJ, Koestler DC, Lester B, Houseman EA, Armstrong DA, Kelsey KT, Marsit CJ. Placental DNA Methylation Related to Both Infant Toenail Mercury and Adverse Neurobehavioral Outcomes. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:723-9. [PMID: 25748564 PMCID: PMC4492267 DOI: 10.1289/ehp.1408561] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 03/04/2015] [Indexed: 05/19/2023]
Abstract
BACKGROUND Prenatal mercury (Hg) exposure is associated with adverse child neurobehavioral outcomes. Because Hg can interfere with placental functioning and cross the placenta to target the fetal brain, prenatal Hg exposure can inhibit fetal growth and development directly and indirectly. OBJECTIVES We examined potential associations between prenatal Hg exposure assessed through infant toenail Hg, placental DNA methylation changes, and newborn neurobehavioral outcomes. METHODS The methylation status of > 485,000 CpG loci was interrogated in 192 placental samples using Illumina's Infinium HumanMethylation450 BeadArray. Hg concentrations were analyzed in toenail clippings from a subset of 41 infants; neurobehavior was assessed using the NICU Network Neurobehavioral Scales (NNNS) in an independent subset of 151 infants. RESULTS We identified 339 loci with an average methylation difference > 0.125 between any two toenail Hg tertiles. Variation among these loci was subsequently found to be associated with a high-risk neurodevelopmental profile (omnibus p-value = 0.007) characterized by the NNNS. Ten loci had p < 0.01 for the association between methylation and the high-risk NNNS profile. Six of 10 loci reside in the EMID2 gene and were hypomethylated in the 16 high-risk profile infants' placentas. Methylation at these loci was moderately correlated (correlation coefficients range, -0.33 to -0.45) with EMID2 expression. CONCLUSIONS EMID2 hypomethylation may represent a novel mechanism linking in utero Hg exposure and adverse infant neurobehavioral outcomes.
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Affiliation(s)
- Jennifer Z J Maccani
- Penn State Tobacco Center of Regulatory Science, Department of Public Health Sciences, College of Medicine, Penn State University, Hershey, Pennsylvania, USA
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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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Puty B, Maximino C, Brasil A, da Silva WLL, Gouveia A, Oliveira KRM, Batista EDJO, Crespo-Lopez ME, Rocha FAF, Herculano AM. Ascorbic acid protects against anxiogenic-like effect induced by methylmercury in zebrafish: action on the serotonergic system. Zebrafish 2014; 11:365-70. [PMID: 24979594 DOI: 10.1089/zeb.2013.0947] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To evaluate the protector effect of ascorbic acid (AA) against anxiogenic-like effect induced by methylmercury (MeHg) exposure, adult zebrafish were treated with AA (2 mg g(-1), intraperitoneal [i.p.]) before MeHg administration (1.0 μg g(-1), i.p.). Groups were tested for the light/dark preference as a behavioral model of anxiety, and the content of serotonin and its oxidized metabolite tryptamine-4,5-dione (T-4,5-D) in the brain was determined by high-performance liquid chromatography. MeHg has produced a marked anxiogenic profile in both tests, and this effect was accompanied by a decrease in the extracellular levels of serotonin, and an increase in the extracellular levels of T-4,5-D. Added to this, a marked increase in the formation of a marker of oxidative stress accompanied these parameters. Interestingly, the anxiogenic-like effect and biochemical alterations induced by MeHg were blocked by pretreatment with AA. These results for the first time demonstrated the potential protector action of AA in neurobehavioral and neurochemical alterations induced by methylmecury exposure demonstrating that zebrafish model could be used as an important tool for testing substances with neuroprotector actions.
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Affiliation(s)
- Bruna Puty
- 1 Laboratory of Neuroendocrinology, Institute of Biological Sciences, Federal University of Para , Belém, Pará, Brazil
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Human Stem/Progenitor Cell-Based Assays for Neurodevelopmental Toxicity Testing. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2014. [DOI: 10.1007/978-1-4939-0521-8_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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McElwee MK, Ho LA, Chou JW, Smith MV, Freedman JH. Comparative toxicogenomic responses of mercuric and methyl-mercury. BMC Genomics 2013; 14:698. [PMID: 24118919 PMCID: PMC3870996 DOI: 10.1186/1471-2164-14-698] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 09/13/2013] [Indexed: 01/16/2023] Open
Abstract
Background Mercury is a ubiquitous environmental toxicant that exists in multiple chemical forms. A paucity of information exists regarding the differences or similarities by which different mercurials act at the molecular level. Results Transcriptomes of mixed-stage C. elegans following equitoxic sub-, low- and high-toxicity exposures to inorganic mercuric chloride (HgCl2) and organic methylmercury chloride (MeHgCl) were analyzed. In C. elegans, the mercurials had highly different effects on transcription, with MeHgCl affecting the expression of significantly more genes than HgCl2. Bioinformatics analysis indicated that inorganic and organic mercurials affected different biological processes. RNAi identified 18 genes that were important in C. elegans response to mercurial exposure, although only two of these genes responded to both mercurials. To determine if the responses observed in C. elegans were evolutionarily conserved, the two mercurials were investigated in human neuroblastoma (SK-N-SH), hepatocellular carcinoma (HepG2) and embryonic kidney (HEK293) cells. The human homologs of the affected C. elegans genes were then used to test the effects on gene expression and cell viability after using siRNA during HgCl2 and MeHgCl exposure. As was observed with C. elegans, exposure to the HgCl2 and MeHgCl had different effects on gene expression, and different genes were important in the cellular response to the two mercurials. Conclusions These results suggest that, contrary to previous reports, inorganic and organic mercurials have different mechanisms of toxicity. The two mercurials induced disparate effects on gene expression, and different genes were important in protecting the organism from mercurial toxicity.
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Affiliation(s)
- Matthew K McElwee
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, NIH, 111 T,W Alexander Drive, Research Triangle Park, P,O, Box 12233, 27709 Durham, NC, USA.
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Sakamoto M, Yasutake A, Domingo JL, Chan HM, Kubota M, Murata K. Relationships between trace element concentrations in chorionic tissue of placenta and umbilical cord tissue: potential use as indicators for prenatal exposure. ENVIRONMENT INTERNATIONAL 2013; 60:106-11. [PMID: 24028800 DOI: 10.1016/j.envint.2013.08.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 08/07/2013] [Accepted: 08/11/2013] [Indexed: 05/17/2023]
Abstract
The role of the placenta was assessed by comparing the profiles of methylmercury (MeHg), inorganic mercury (I-Hg), lead (Pb), cadmium (Cd), selenium (Se), zinc (Zn), and copper (Cu) in freeze-dried chorionic tissue of the placenta and umbilical cord tissue. The significance of the placenta and cord tissue as predictors of prenatal exposure to these trace elements in pregnant women and newborns was also examined by comparing the element profiles among placenta and cord tissue, and maternal and cord blood red blood cells (RBCs). The samples were collected from 48 mother-child pairs at birth in the general population of Japanese. The concentrations of all elements, except for MeHg, were significantly higher in placenta than in cord tissue. In particular, the Cd showed the highest placenta vs. cord tissue ratio (59:1), followed by I-Hg (2.4:1), indicating that the placental barrier works most strongly against Cd among the examined toxic elements. Contrary to the other elements, the MeHg concentration in cord tissue was significantly higher (1.6 times) than that in placenta, indicating its exceptionally high placental transfer. The MeHg in placenta showed significant correlations with total mercury (T-Hg) in maternal and cord RBCs (rs=0.80 and 0.91, respectively). The MeHg in cord tissue also showed significant correlations with T-Hg in maternal and cord RBCs (rs=0.75 and 0.85, respectively). Therefore, both placenta and cord tissue are useful for predicting maternal and fetal exposure to MeHg. The Se concentration in placenta showed significant but moderate correlations with that in maternal and cord RBCs (rs=0.38 and 0.57, respectively). The Pb, Zn, and Cu concentrations in placenta and cord tissue showed no significant correlations with those in maternal and cord RBCs. As an exception, the Cd concentration in placenta showed a moderate but significant correlation (rs=0.41) with that in maternal RBCs, suggesting that the placenta is useful for predicting maternal exposure to Cd during gestation.
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Affiliation(s)
- Mineshi Sakamoto
- Department of Environmental Science and Epidemiology, National Institute for Minamata Disease, Minamata, Japan.
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Sokolowski K, Obiorah M, Robinson K, McCandlish E, Buckley B, DiCicco-Bloom E. Neural stem cell apoptosis after low-methylmercury exposures in postnatal hippocampus produce persistent cell loss and adolescent memory deficits. Dev Neurobiol 2013; 73:936-49. [PMID: 23959606 DOI: 10.1002/dneu.22119] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 07/18/2013] [Accepted: 08/07/2013] [Indexed: 11/09/2022]
Abstract
The developing brain is particularly sensitive to exposures to environmental contaminants. In contrast to the adult, the developing brain contains large numbers of dividing neuronal precursors, suggesting that they may be vulnerable targets. The postnatal day 7 (P7) rat hippocampus has populations of both mature neurons in the CA1-3 region as well as neural stem cells (NSC) in the dentate gyrus (DG) hilus, which actively produce new neurons that migrate to the granule cell layer (GCL). Using this well-characterized NSC population, we examined the impact of low levels of methylmercury (MeHg) on proliferation, neurogenesis, and subsequent adolescent learning and memory behavior. Assessing a range of exposures, we found that a single subcutaneous injection of 0.6 µg/g MeHg in P7 rats induced caspase activation in proliferating NSC of the hilus and GCL. This acute NSC death had lasting impact on the DG at P21, reducing cell numbers in the hilus by 22% and the GCL by 27%, as well as reductions in neural precursor proliferation by 25%. In contrast, non-proliferative CA1-3 pyramidal neuron cell number was unchanged. Furthermore, animals exposed to P7 MeHg exhibited an adolescent spatial memory deficit as assessed by Morris water maze. These results suggest that environmentally relevant levels of MeHg exposure may decrease NSC populations and, despite ongoing neurogenesis, the brain may not restore the hippocampal cell deficits, which may contribute to hippocampal-dependent memory deficits during adolescence.
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Affiliation(s)
- Katie Sokolowski
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey/Rutgers Graduate School of Biomedical Sciences, Piscataway, New Jersey; Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey
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Ondovcik SL, Preston TJ, McCallum GP, Wells PG. Expression of human oxoguanine glycosylase 1 or formamidopyrimidine glycosylase in human embryonic kidney 293 cells exacerbates methylmercury toxicity in vitro. Toxicol Appl Pharmacol 2013; 271:41-8. [DOI: 10.1016/j.taap.2013.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 03/19/2013] [Accepted: 04/01/2013] [Indexed: 10/26/2022]
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Santiago SE, Park GH, Huffman KJ. Consumption habits of pregnant women and implications for developmental biology: a survey of predominantly Hispanic women in California. Nutr J 2013; 12:91. [PMID: 23815874 PMCID: PMC3704911 DOI: 10.1186/1475-2891-12-91] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 06/12/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Healthy post-pregnancy outcomes are contingent upon an informed regimen of prenatal care encouraging healthy maternal consumption habits. In this article, we describe aspects of maternal intake of food, drink, and medication in a population of predominantly Hispanic women in Southern California. Potential implications for unhealthy prenatal dietary choices are discussed. METHODS The Food, Beverage, and Medication Intake Questionnaire (FBMIQ) measures common practices of maternal consumption during pregnancy. The FBMIQ was administered to English and Spanish speaking pregnant and recently pregnant (36 weeks pregnant - 8 weeks post-partum) women over the age of 18 who were receiving care from a private medical group in Downey CA. RESULTS A total of 200 women completed the FBMIQ. Consumption habits of healthy foods and beverages, unhealthy foods, unhealthy beverages, and medication are characterized in this article. Data indicate widespread consumption of fresh fruit, meats, milk and juice and indicate most women used prenatal vitamin supplements. Studies in developmental neuroscience have shown that certain substances may cause teratogenic effects on the fetus when ingested by the mother during pregnancy. Those potentially harmful substances included in our study were Bisphenol-A (BPA), methylmercury, caffeine, alcohol and certain medications. Our results show that a proportion of the women surveyed in our study consumed BPA, methylmercury, caffeine, alcohol, and certain medications at varied levels during pregnancy. This represents an interesting finding and suggests a disconnect between scientific data and general recommendations provided to pregnant mothers by obstetricians. CONCLUSIONS The results of our study demonstrate that a proportion of pregnant women consume substances that are potentially teratogenic and may impact the health and well being of the offspring. It is important to appraise healthy and unhealthy consumption habits in order to encourage healthy practices and alleviate future effects of preventable, toxin-induced developmental issues. Prenatal advising should discourage the consumption of dangerous foods, beverages, and medications that women commonly report eating during pregnancy.
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Affiliation(s)
- Sarah E Santiago
- Department of Psychology, University of California, 900 University Avenue, Riverside, CA, 92521-0128, California
| | - Grace H Park
- Department of Psychology, University of California, 900 University Avenue, Riverside, CA, 92521-0128, California
| | - Kelly J Huffman
- Department of Psychology, University of California, 900 University Avenue, Riverside, CA, 92521-0128, California
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Ondovcik SL, Tamblyn L, McPherson JP, Wells PG. Sensitivity to methylmercury toxicity is enhanced in oxoguanine glycosylase 1 knockout murine embryonic fibroblasts and is dependent on cellular proliferation capacity. Toxicol Appl Pharmacol 2013; 270:23-30. [DOI: 10.1016/j.taap.2013.02.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 02/20/2013] [Accepted: 02/22/2013] [Indexed: 12/16/2022]
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de Paula Martins R, Glaser V, da Luz Scheffer D, de Paula Ferreira PM, Wannmacher CMD, Farina M, de Oliveira PA, Prediger RD, Latini A. Platelet oxygen consumption as a peripheral blood marker of brain energetics in a mouse model of severe neurotoxicity. J Bioenerg Biomembr 2013; 45:449-57. [PMID: 23471523 DOI: 10.1007/s10863-013-9499-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 01/30/2013] [Indexed: 01/12/2023]
Abstract
Interactions of chemicals with cerebral cellular systems are often accompanied by similar changes involving components in non-neural tissues. On this basis, indirect strategies have been developed to investigate neural cell function parameters by methods using accessible cells, including platelets and/or peripheral blood lymphocytes. Therefore, here it was investigated whether peripheral blood markers may be useful for assessing the central toxic effects of methylmercury (MeHg). For this purpose, we investigated platelet mitochondrial physiology in a well-established mouse model of MeHg-induced neurotoxicity, and correlated this peripheral activity with behavioural and central biochemical parameters. In order to characterize the cortical toxicity induced by MeHg (20 and 40 mg/L in drinking water, 21 days), the behavioral parameter namely, short-term object recognition, and the central mitochondrial impairment assessed by measuring respiratory complexes I-IV enzyme activities were determined in MeHg-poisoned animals. Neurotoxicity induced by MeHg exposure provoked compromised cortical activity (memory impairment) and reduced NADH dehydrogenase, complex II and II-III activities in the cerebral cortex. These alterations correlated with impaired systemic platelet oxygen consumption of intoxicated mice, which was characterized by reduced electron transfer activity and uncoupled mitochondria. The data brought here demonstrated that impaired systemic platelet oxygen consumption is a sensitive and non-invasive marker of the brain energy deficits induced by MeHg poisoning. Finally, brain and platelets biochemical alterations significantly correlated with cognitive behavior in poisoned mice. Therefore, it could be proposed the use of platelet oxygen consumption as a peripheral blood marker of brain function in a mouse model MeHg-induced neurotoxicity.
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Affiliation(s)
- Roberta de Paula Martins
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil,
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Radonjic M, Cappaert NLM, de Vries EFJ, de Esch CEF, Kuper FC, van Waarde A, Dierckx RAJO, Wadman WJ, Wolterbeek APM, Stierum RH, de Groot DMG. Delay and Impairment in Brain Development and Function in Rat Offspring After Maternal Exposure to Methylmercury. Toxicol Sci 2013; 133:112-24. [DOI: 10.1093/toxsci/kft024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Low level prenatal exposure to methylmercury disrupts neuronal migration in the developing rat cerebral cortex. Toxicology 2012; 304:57-68. [PMID: 23220560 DOI: 10.1016/j.tox.2012.11.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/11/2012] [Accepted: 11/15/2012] [Indexed: 11/22/2022]
Abstract
We determined the effects of low-level prenatal MeHg exposure on neuronal migration in the developing rat cerebral cortex using in utero electroporation. We used offspring rats born to dams that had been exposed to saline or various doses of MeHg (0.01 mg/kg/day, 0.1 mg/kg/day, and 1 mg/kg/day) from gestational day (GD) 11-21. Immunohistochemical examination of the brains of the offspring was conducted on postnatal day (PND) 0, PND3, and PND7. Our results showed that prenatal exposure to low levels of MeHg (0.1 mg/kg/day or 1 mg/kg/day) during the critical stage in neuronal migration resulted in migration defects of the cerebrocortical neurons in offspring rats. Importantly, our data revealed that the abnormal neuronal distribution induced by MeHg was not caused by altered proliferation of neural progenitor cells (NPCs), induction of apoptosis of NPCs and/or newborn neurons, abnormal differentiation of NPCs, and the morphological changes of radial glial scaffold, indicating that the defective neuronal positioning triggered by exposure to low-dose of MeHg is due to the impacts of MeHg on the process of neuronal migration itself. Moreover, we demonstrated that in utero exposure to low-level MeHg suppresses the expression of Rac1, Cdc42, and RhoA, which play key roles in the migration of cerebrocortical neurons during the early stage of brain development, suggesting that the MeHg-induced migratory disturbance of cerebrocortical neurons is likely associated with the Rho GTPases signal pathway. In conclusion, our results provide a novel perspective on clarifying the mechanisms underlying the impairment of neuronal migration induced by MeHg.
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Krug AK, Kolde R, Gaspar JA, Rempel E, Balmer NV, Meganathan K, Vojnits K, Baquié M, Waldmann T, Ensenat-Waser R, Jagtap S, Evans RM, Julien S, Peterson H, Zagoura D, Kadereit S, Gerhard D, Sotiriadou I, Heke M, Natarajan K, Henry M, Winkler J, Marchan R, Stoppini L, Bosgra S, Westerhout J, Verwei M, Vilo J, Kortenkamp A, Hescheler J, Hothorn L, Bremer S, van Thriel C, Krause KH, Hengstler JG, Rahnenführer J, Leist M, Sachinidis A. Human embryonic stem cell-derived test systems for developmental neurotoxicity: a transcriptomics approach. Arch Toxicol 2012. [PMID: 23179753 PMCID: PMC3535399 DOI: 10.1007/s00204-012-0967-3] [Citation(s) in RCA: 177] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Developmental neurotoxicity (DNT) and many forms of reproductive toxicity (RT) often manifest themselves in functional deficits that are not necessarily based on cell death, but rather on minor changes relating to cell differentiation or communication. The fields of DNT/RT would greatly benefit from in vitro tests that allow the identification of toxicant-induced changes of the cellular proteostasis, or of its underlying transcriptome network. Therefore, the ‘human embryonic stem cell (hESC)-derived novel alternative test systems (ESNATS)’ European commission research project established RT tests based on defined differentiation protocols of hESC and their progeny. Valproic acid (VPA) and methylmercury (MeHg) were used as positive control compounds to address the following fundamental questions: (1) Does transcriptome analysis allow discrimination of the two compounds? (2) How does analysis of enriched transcription factor binding sites (TFBS) and of individual probe sets (PS) distinguish between test systems? (3) Can batch effects be controlled? (4) How many DNA microarrays are needed? (5) Is the highest non-cytotoxic concentration optimal and relevant for the study of transcriptome changes? VPA triggered vast transcriptional changes, whereas MeHg altered fewer transcripts. To attenuate batch effects, analysis has been focused on the 500 PS with highest variability. The test systems differed significantly in their responses (<20 % overlap). Moreover, within one test system, little overlap between the PS changed by the two compounds has been observed. However, using TFBS enrichment, a relatively large ‘common response’ to VPA and MeHg could be distinguished from ‘compound-specific’ responses. In conclusion, the ESNATS assay battery allows classification of human DNT/RT toxicants on the basis of their transcriptome profiles.
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Affiliation(s)
- Anne K. Krug
- Department of Biology, University of Konstanz (UKN), 78457 Constance, Germany
| | - Raivo Kolde
- OÜ Quretec (Qure), Limited Liability Company, 51003 Tartu, Estonia
- Institute of Computer Science, University of Tartu, 50409 Tartu, Estonia
| | - John A. Gaspar
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Eugen Rempel
- Department of Statistics, TU Dortmund University , 44221 Dortmund, Germany
| | - Nina V. Balmer
- Department of Biology, University of Konstanz (UKN), 78457 Constance, Germany
| | - Kesavan Meganathan
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Kinga Vojnits
- Commission of the European Communities (JRC) Joint Research Centre, 1049 Brussels, Belgium
| | - Mathurin Baquié
- Department of Pathology and Immunology, Geneva Medical Faculty, University of Geneva (UNIGE), 1211 Geneva 4, Switzerland
| | - Tanja Waldmann
- Department of Biology, University of Konstanz (UKN), 78457 Constance, Germany
| | - Roberto Ensenat-Waser
- Commission of the European Communities (JRC) Joint Research Centre, 1049 Brussels, Belgium
| | - Smita Jagtap
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
| | | | - Stephanie Julien
- Department of Pathology and Immunology, Geneva Medical Faculty, University of Geneva (UNIGE), 1211 Geneva 4, Switzerland
| | - Hedi Peterson
- Department of Pathology and Immunology, Geneva Medical Faculty, University of Geneva (UNIGE), 1211 Geneva 4, Switzerland
| | - Dimitra Zagoura
- Commission of the European Communities (JRC) Joint Research Centre, 1049 Brussels, Belgium
| | - Suzanne Kadereit
- Department of Biology, University of Konstanz (UKN), 78457 Constance, Germany
| | - Daniel Gerhard
- Gottfried Wilhelm Leibniz University (LUH), Institute for Biostatistics, 30167 Hannover, Germany
| | - Isaia Sotiriadou
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Michael Heke
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Karthick Natarajan
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Margit Henry
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Johannes Winkler
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Rosemarie Marchan
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Technical University of Dortmund, 44139 Dortmund, Germany
| | - Luc Stoppini
- Department of Pathology and Immunology, Geneva Medical Faculty, University of Geneva (UNIGE), 1211 Geneva 4, Switzerland
| | - Sieto Bosgra
- Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO), 2628 VK Delft, The Netherlands
| | - Joost Westerhout
- Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO), 2628 VK Delft, The Netherlands
| | - Miriam Verwei
- Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO), 2628 VK Delft, The Netherlands
| | - Jaak Vilo
- OÜ Quretec (Qure), Limited Liability Company, 51003 Tartu, Estonia
- Institute of Computer Science, University of Tartu, 50409 Tartu, Estonia
| | | | - Jürgen Hescheler
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Ludwig Hothorn
- Gottfried Wilhelm Leibniz University (LUH), Institute for Biostatistics, 30167 Hannover, Germany
| | - Susanne Bremer
- Commission of the European Communities (JRC) Joint Research Centre, 1049 Brussels, Belgium
| | - Christoph van Thriel
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Technical University of Dortmund, 44139 Dortmund, Germany
| | - Karl-Heinz Krause
- Department of Pathology and Immunology, Geneva Medical Faculty, University of Geneva (UNIGE), 1211 Geneva 4, Switzerland
| | - Jan G. Hengstler
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Technical University of Dortmund, 44139 Dortmund, Germany
| | - Jörg Rahnenführer
- Department of Statistics, TU Dortmund University , 44221 Dortmund, Germany
| | - Marcel Leist
- Department of Biology, University of Konstanz (UKN), 78457 Constance, Germany
| | - Agapios Sachinidis
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne (UKK), Robert-Koch-Str. 39, 50931 Cologne, Germany
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Sakamoto M, Chan HM, Domingo JL, Kubota M, Murata K. Changes in body burden of mercury, lead, arsenic, cadmium and selenium in infants during early lactation in comparison with placental transfer. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 84:179-84. [PMID: 22854743 DOI: 10.1016/j.ecoenv.2012.07.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 07/07/2012] [Accepted: 07/09/2012] [Indexed: 05/23/2023]
Abstract
The developing brains of both fetuses and infants are susceptible to environmental contaminants. However, the contribution of breast-feeding to the element body burden in infants remains unclear. The main objective of this study was to investigate the changes in body burden of elements such as methylmercury, lead, arsenic, cadmium, and selenium in infants during a 3-month breast-feeding period compared with placental transfer of the elements. Element concentrations were measured in maternal and umbilical cord (fetus) red blood cells (RBCs) at parturition and in infant RBCs at 3 months. Most of the mercury in RBCs is in the methyl form, and the total mercury concentration in RBCs reflects methylmercury exposure. The mercury level in cord RBCs was approximately 1.5 times higher than that in mothers, while in infants, it declined by approximately 60% after 3-months' breast-feeding. The cord selenium level was similar to the maternal level, but declined approximately 75% after 3-months' breast-feeding in infants. Lead and arsenic concentrations in cord RBCs were about 60% of the maternal levels, and remained constant until the 3-month study period. The cadmium level in cord RBCs was about 20% of that in maternal RBCs, and remained almost constant until the end of the 3-month study period. In conclusion, although pregnant women should pay attention to avoid high methylmercury exposure, element exposure through breast-feeding does not pose any great concern in this population.
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Affiliation(s)
- Mineshi Sakamoto
- Department of Epidemiology, National Institute for Minamata Disease, Minamata, Japan.
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Lucena GM, Prediger RD, Silva MV, Santos SN, Silva JFB, Santos ARS, Azevedo MS, Ferreira VM. Ethanolic extract from bulbs of Cipura paludosa reduced long-lasting learning and memory deficits induced by prenatal methylmercury exposure in rats. Dev Cogn Neurosci 2012; 3:1-10. [PMID: 23245215 DOI: 10.1016/j.dcn.2012.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 08/16/2012] [Accepted: 08/17/2012] [Indexed: 01/12/2023] Open
Abstract
Previous studies from our group have indicated important biological properties of the ethanolic extract (EE) and isolated compounds from the bulbs of Cipura paludosa (Iridaceae), a native plant widely distributed in northern Brazil. In the present study, the effects of chronic treatment with the EE on the memory of adult rats exposed to methylmercury (MeHg) during early development were assessed. Pregnant rats were treated by gavage with a single dose of MeHg (8 mg/kg) on gestational day 15, the developmental stage critical for cortical neuron proliferation. Adult offspring were administered orally with the EE of C. paludosa (1, 10 or 100mg/kg) over 14 consecutive days. EE improved short-term social memory in a specific manner and facilitated the step-down inhibitory avoidance of short- and long-term memory. MeHg exposure induced pronounced long-lasting impairments in social recognition memory that were improved by EE. Moreover, EE significantly increased the step-down latencies specifically during the short-term session in prenatal MeHg-exposed rats. These results demonstrate that EE reduced the long-lasting short-term learning and memory deficits induced by MeHg exposure. These findings may encourage further studies evaluating the cognitive enhancing properties of C. paludosa and its components on neuropathological conditions associated with exposure to environmental contaminants.
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Sakamoto M, Chan HM, Domingo JL, Kawakami S, Murata K. Mercury and docosahexaenoic acid levels in maternal and cord blood in relation to segmental maternal hair mercury concentrations at parturition. ENVIRONMENT INTERNATIONAL 2012; 44:112-117. [PMID: 22425897 DOI: 10.1016/j.envint.2012.02.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 02/13/2012] [Accepted: 02/22/2012] [Indexed: 05/31/2023]
Abstract
Fish is a major source of harmful methylmercury (MeHg) and beneficial docosahexaenoic acid (DHA) in the developing brain. In this study, we investigated the correlations among maternal and umbilical cord (cord) MeHg and DHA levels at parturition, and mercury (Hg) concentration in 1-cm incremental segments hair samples which grew during gestation representing monthly MeHg exposure levels throughout the period. Whole blood Hg and plasma DHA levels were measured in blood sample pairs collected from 54 mothers at early gestation and parturition, and in cord blood. Maternal hair samples were collected at parturition, and Hg concentrations were measured in 1-cm incremental segments. Hg level in mothers at parturition was slightly lower than that at early gestation and the level in cord blood were approximately 1.9 times higher than that in mothers at parturition. On the other hand, DHA level in mothers at parturition was approximately 2.3 and 1.6 times higher than those in mothers at early gestation and in cord plasma, respectively. These results indicate that kinetics of these chemicals in mothers during gestation and placental transfer are completely different. However, Hg and DHA levels had significant positive correlation in fetal circulation. The cord blood Hg showed the strongest correlation with maternal hair Hg in the first 1-cm segment from the scalp at parturition (r=0.87), indicating that fetal MeHg level reflects maternal MeHg burden at late gestation. In contrast, maternal and cord plasma DHA concentrations at parturition showed the highest correlation coefficients with Hg in the fifth (r=0.43) and fourth (r=0.38) 1-cm hair segments, suggesting that maternal and fetal DHA levels reflects maternal fish intake during mid-gestation.
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Affiliation(s)
- Mineshi Sakamoto
- Department of Epidemiology, National Institute for Minamata Disease, Minamata, Japan.
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45
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He X, Imanishi S, Sone H, Nagano R, Qin XY, Yoshinaga J, Akanuma H, Yamane J, Fujibuchi W, Ohsako S. Effects of methylmercury exposure on neuronal differentiation of mouse and human embryonic stem cells. Toxicol Lett 2012; 212:1-10. [PMID: 22555245 DOI: 10.1016/j.toxlet.2012.04.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 04/13/2012] [Accepted: 04/16/2012] [Indexed: 12/19/2022]
Abstract
The establishment of more efficient in vitro approaches has been widely acknowledged as a critical need for toxicity testing. In this study, we examined the effects of methylmercury (MeHg), which is a well-known developmental neurotoxicant, in two neuronal differentiation systems of mouse and human embryonic stem cells (mESCs and hESCs, respectively). Embryoid bodies were generated from gathering of mESCs and hESCs using a micro-device and seeded onto ornithine-laminin-coated plates to promote proliferation and neuronal differentiation. The cells were exposed to MeHg from the start of neuronal induction until the termination of cultures, and significant reductions of mESCs and hESCs were observed in the cell viability assays at 1,10,100 and 1000nM, respectively. Although the mESC derivatives were more sensitive than the hESC derivatives to MeHg exposure in terms of cell viability, the morphological evaluation demonstrated that the neurite length and branch points of hESC derivatives were more susceptible to a low concentration of MeHg. Then, the mRNA levels of differentiation markers were examined using quantitative RT-PCR analysis and the interactions between MeHg exposure and gene expression levels were visualized using a network model based on a Bayesian algorithm. The Bayesian network analysis showed that a MeHg-node was located on the highest hierarchy in the hESC derivatives, but not in the mESC derivatives, suggesting that MeHg directly affect differentiation marker genes in hESCs. Taken together, effects of MeHg were observed in our neuronal differentiation systems of mESCs and hESCs using a combination of morphological and molecular markers. Our study provided possible, but limited, evidences that human ESC models might be more sensitive in particular endpoints in response to MeHg exposure than that in mouse ESC models. Further investigations that expand on the findings of the present paper may solve problems that occur when the outcomes from laboratory animals are extrapolated for human risk evaluation.
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Affiliation(s)
- Xiaoming He
- Division of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
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46
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Ondovcik SL, Tamblyn L, McPherson JP, Wells PG. Oxoguanine glycosylase 1 (OGG1) protects cells from DNA double-strand break damage following methylmercury (MeHg) exposure. Toxicol Sci 2012; 128:272-83. [PMID: 22523232 DOI: 10.1093/toxsci/kfs138] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Methylmercury (MeHg) is a potent neurotoxin, teratogen, and probable carcinogen, but the underlying mechanisms of its actions remain unclear. Although MeHg causes several types of DNA damage, the toxicological consequences of this macromolecular damage are unknown. MeHg enhances oxidative stress, which can cause various oxidative DNA lesions that are primarily repaired by oxoguanine glycosylase 1 (OGG1). Herein, we compared the response of wild-type and OGG1 null (Ogg1(-/-)) murine embryonic fibroblasts to environmentally relevant, low micromolar concentrations of MeHg by measuring clonogenic efficiency, cell cycle arrest, DNA double-strand breaks (DSBs), and activation of the DNA damage response pathway.Ogg1(-/-) cells exhibited greater sensitivity to MeHg than wild-type controls, as measured by the clonogenic assay, and showed a greater propensity for MeHg-initiated apoptosis. Both wild-type and Ogg1(-/-) cells underwent cell cycle arrest when exposed to micromolar concentrations of MeHg; however, the extent of DSBs was exacerbated in Ogg1(-/-) cells compared with that in wild-type controls. Pretreatment with the antioxidative enzyme catalase reduced levels of DSBs in both wild-type and Ogg1(-/-) cells but failed to block MeHg-initiated apoptosis at micromolar concentrations. Our findings implicate reactive oxygen species mediated DNA damage in the mechanism of MeHg toxicity; and demonstrate for the first time that impaired DNA repair capacity enhances cellular sensitivity to MeHg. Accordingly, the genotoxic properties of MeHg may contribute to its neurotoxic and teratogenic effects, and an individual's response to oxidative stress and DNA damage may constitute an important determinant of risk.
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Affiliation(s)
- Stephanie L Ondovcik
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
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Mori N, Yasutake A, Marumoto M, Hirayama K. Methylmercury inhibits electron transport chain activity and induces cytochrome c release in cerebellum mitochondria. J Toxicol Sci 2011; 36:253-9. [PMID: 21628953 DOI: 10.2131/jts.36.253] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The involvement of oxidative stress has been suggested as a mechanism for toxicity caused by methylmercury (MeHg). One of the major critical sites for oxidative stress is the mitochondria. In this research, to clarify the target site in mitochondria affected by MeHg, the individual activities of the mitochondrial electron transport chain (ETC) (I∼IV) were examined in the liver, cerebrum and cerebellum of MeHg-intoxicated rats. In addition, to elucidate the mechanism underlying MeHg toxicity, cytochrome c release, caspase 3 activity and histological study were examined in the cerebrum and cerebellum. The cerebellum was found to be an exclusive tissue in which significant MeHg-induced alterations were observed. The complex II activity in the cerebellum mitochondria significantly decreased after MeHg exposure. Cytochrome c release from mitochondria increased only in the cerebellum by MeHg exposure. However, no significant alterations in caspase 3 activity or histological structure were found in brain tissues. These results suggest that MeHg acts on the constituents of complex II in the cerebellum, and induces mitochondrial dysfunction, leading to a release of cytochrome c from mitochondria. These events were considered to occur at the early stage of MeHg intoxication.
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Affiliation(s)
- Nobuko Mori
- Department of Biomedical Laboratory Sciences, Faculty of Life Sciences, Kumamoto University, 4-24-1, Kuhonji, Kumamoto 862-0976, Japan.
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Yin Z, Lee E, Ni M, Jiang H, Milatovic D, Rongzhu L, Farina M, Rocha JBT, Aschner M. Methylmercury-induced alterations in astrocyte functions are attenuated by ebselen. Neurotoxicology 2011; 32:291-9. [PMID: 21300091 PMCID: PMC3079013 DOI: 10.1016/j.neuro.2011.01.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 12/21/2010] [Accepted: 01/08/2011] [Indexed: 12/26/2022]
Abstract
Methylmercury (MeHg) preferentially accumulates in glia of the central nervous system (CNS), but its toxic mechanisms have yet to be fully recognized. In the present study, we tested the hypothesis that MeHg induces neurotoxicity via oxidative stress mechanisms, and that these effects are attenuated by the antioxidant, ebselen. Rat neonatal primary cortical astrocytes were pretreated with or without 10 μM ebselen for 2h followed by MeHg (0, 1, 5, and 10 μM) treatments. MeHg-induced changes in astrocytic [(3)H]-glutamine uptake were assessed along with changes in mitochondrial membrane potential (ΔΨ(m)), using the potentiometric dye tetramethylrhodamine ethyl ester (TMRE). Western blot analysis was used to detect MeHg-induced ERK (extracellular-signal related kinase) phosphorylation and caspase-3 activation. MeHg treatment significantly decreased (p<0.05) astrocytic [(3)H]-glutamine uptake at all time points and concentrations. Ebselen fully reversed MeHg's (1 μM) effect on [(3)H]-glutamine uptake at 1 min. At higher MeHg concentrations, ebselen partially reversed the MeHg-induced astrocytic inhibition of [(3)H]-glutamine uptake [at 1 min (5 and 10 μM) (p<0.05); 5 min (1, 5 and 10 μM) (p<0.05)]. MeHg treatment (1h) significantly (p<0.05) dissipated the ΔΨ(m) in astrocytes as evidenced by a decrease in mitochondrial TMRE fluorescence. Ebselen fully reversed the effect of 1 μM MeHg treatment for 1h on astrocytic ΔΨ(m) and partially reversed the effect of 5 and 10 μM MeHg treatments for 1h on ΔΨ(m). In addition, ebselen inhibited MeHg-induced phosphorylation of ERK (p<0.05) and blocked MeHg-induced activation of caspase-3 (p<0.05-0.01). These results are consistent with the hypothesis that MeHg exerts its toxic effects via oxidative stress and that the phosphorylation of ERK and the dissipation of the astrocytic mitochondrial membrane potential are involved in MeHg toxicity. In addition, the protective effects elicited by ebselen reinforce the idea that organic selenocompounds represent promising strategies to counteract MeHg-induced neurotoxicity.
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MESH Headings
- Analysis of Variance
- Animals
- Animals, Newborn
- Antioxidants/pharmacology
- Astrocytes/drug effects
- Astrocytes/metabolism
- Astrocytes/pathology
- Azoles/pharmacology
- Blotting, Western
- Caspase 3/metabolism
- Cells, Cultured
- Cytoprotection
- Dose-Response Relationship, Drug
- Environmental Pollutants/toxicity
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Glutamine/metabolism
- Isoindoles
- Membrane Potential, Mitochondrial/drug effects
- Mercury Poisoning, Nervous System/etiology
- Mercury Poisoning, Nervous System/metabolism
- Mercury Poisoning, Nervous System/pathology
- Methylmercury Compounds/toxicity
- Microscopy, Fluorescence
- Mitochondria/drug effects
- Mitochondria/metabolism
- Neuroprotective Agents/pharmacology
- Organoselenium Compounds/pharmacology
- Oxidative Stress/drug effects
- Phosphorylation
- Rats
- Rats, Sprague-Dawley
- Time Factors
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Affiliation(s)
- Zhaobao Yin
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Eunsook Lee
- Department of Physiology, Meharry Medical College, Nashville, Tennessee
| | - Mingwei Ni
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Haiyan Jiang
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Dejan Milatovic
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lu Rongzhu
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Joao B. T. Rocha
- Departamento de Bioquímica, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Michael Aschner
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
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White RF, Palumbo CL, Yurgelun-Todd DA, Heaton KJ, Weihe P, Debes F, Grandjean P. Functional MRI approach to developmental methylmercury and polychlorinated biphenyl neurotoxicity. Neurotoxicology 2011; 32:975-80. [PMID: 21545807 DOI: 10.1016/j.neuro.2011.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/01/2011] [Accepted: 04/01/2011] [Indexed: 10/18/2022]
Abstract
Prenatal and early childhood exposure to methylmercury (MeHg) or polychlorinated biphenyls (PCBs) are associated with deficits in cognitive, sensory, motor and other functions measured by neurobehavioral tests. The main objective of this pilot study was to determine whether functional magnetic resonance imaging (fMRI) is effective for visualization of brain function alterations related to neurobehavior in subjects with high prenatal exposure to the two neurotoxicants, MeHg and PCBs. Twelve adolescents (all boys) from a Faroese birth cohort assembled in 1986-1987 were recruited based on their prenatal exposures to MeHg and PCB. All underwent fMRI scanning during behavioral tasks at age 15 years. Subjects with high mixed exposure to MeHg and PCBs were compared to those with low mixed exposure on fMRI photic stimulation and a motor task. Boys with low mixed exposures showed patterns of fMRI activation during visual and motor tasks that are typical of normal control subjects. However, those with high exposures showed activation in more areas of the brain and different and wider patterns of activation than the low mixed exposure group. The brain activation patterns observed in association with increased exposures to MeHg and PCBs are meaningful in regard to the known neurotoxicity of these substances. This methodology therefore has potential utility in visualizing structural neural system determinants of exposure-induced neurobehavioral dysfunction.
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Affiliation(s)
- Roberta F White
- Department of Environmental Health, Boston University School of Public Health, Boston, MA, USA.
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Developing central nervous system and vulnerability to platinum compounds. CHEMOTHERAPY RESEARCH AND PRACTICE 2011; 2011:315418. [PMID: 22312552 PMCID: PMC3265252 DOI: 10.1155/2011/315418] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 12/21/2010] [Indexed: 12/12/2022]
Abstract
Comparative studies on the effects of the platinum complexes in use or in clinical trials are carried out in order to discover differences in the neurotoxic potential and the reversibility of neurotoxicity. In this paper, we summarized the current literature on neurotoxicity and chemoresistance of cisplatin (cisPt) and discussed our recent efforts on the interference of cisPt and a new platinum compound [Pt(O,O′-acac)(γ-acac)(DMS)] (PtAcacDMS), with high specific reactivity with sulphur ligands instead of nucleobases as cisPt, on some crucial events of rat postnatal cerebellum development. The acute effects of drug treatments on cell proliferation and death in the external granular layer and granule cell migration and the late effects on the dendrite growth of Purkinje cells were evaluated. Together with the demonstrated antineoplastic effectiveness in vitro, compared with cisPt, data suggest a lower neurotoxicity of PtAcacDMS, in spite of its presence in the brain that involves considerations on the blood brain barrier permeability.
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