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de Paula HK, Love TM, Pineda D, Watson GE, Thurston SW, Yeates AJ, Mulhern MS, McSorley EM, Strain JJ, Shamlaye CF, Myers GJ, Rand MD, van Wijngaarden E, Broberg K. KEAP1 polymorphisms and neurodevelopmental outcomes in children with exposure to prenatal MeHg from the Seychelles Child Development Study Nutrition Cohort 2. Neurotoxicology 2023; 99:177-183. [PMID: 37858899 PMCID: PMC10841683 DOI: 10.1016/j.neuro.2023.10.008] [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: 06/30/2023] [Revised: 09/25/2023] [Accepted: 10/14/2023] [Indexed: 10/21/2023]
Abstract
BACKGROUND Humans differ in the metabolism of the neurotoxicant methyl mercury (MeHg). This variation may be partially due to variation in genes encoding the transcription factor Nuclear factor E2-related factor 2 (NRF2) and its negative regulator Kelch-like ECH-Associated Protein 1 (KEAP1), which regulate glutathione and related transporter and antioxidant proteins that play a role in the metabolism and neurotoxicity of MeHg. AIM To elucidate a potential risk from genetic variation in NFE2L2 (encoding NRF2) and KEAP1 toward prenatal mercury exposure and child neurodevelopmental outcomes at 20 months and 7 years of age in a population with variable prenatal exposure to MeHg from maternal fish consumption. MATERIAL AND METHODS Nutrition Cohort 2 is a mother-child cohort in the Republic of Seychelles. Children were genotyped for NFE2L2 (rs2364723, rs13001694) and KEAP1 (rs8113472, rs9676881) polymorphisms (N = 1285 after removing siblings). Total mercury (Hg) was measured in cord blood as a biomarker for prenatal MeHg exposure. Child neurodevelopmental outcomes included the Bayley Scales of Infant Development II administered at 20 months of age, and outcomes across multiple neurodevelopmental domains from 14 tests administered in children and 3 instruments completed by parents when children were 7 years of age. RESULTS The mean cord blood MeHg concentration was 34 (95% CI 11, 75) µg/L. None of the four polymorphisms had a significant association (p < 0.05) with either cord MeHg or neurodevelopmental test results at 20 months. There were no significant associations between either NFE2L2 polymorphism and any developmental test scores. At 7 years, children carrying KEAP1 rs8113472 CA showed significantly worse performance on psychomotor function than children with the CC variant (finger tapping, dominant hand: β - 1.19, SE 0.34; finger tapping, non-dominant hand: β - 0.92, SE 0.31) and worse social communication (SCQ Total: β 0.65, SE 0.27). Children carrying rs8113472 AA, versus children with CC, showed significantly better performance on social communication (SRS Total: β - 8.88, SE 3.60). Children carrying KEAP1 rs9676881 AG, versus children with GG, showed significantly worse performance on psychomotor function (trailmaking A time: β 8.66, SE 3.37) and cognition (KBIT Matrices: β - 0.96, SE 0.36). CONCLUSION No associations between NFE2L2 and KEAP1 polymorphisms and MeHg concentration were identified. However, at 7 years, KEAP1 polymorphisms were associated with differences in neurodevelopmental outcomes in children from a population with high fish intake.
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Affiliation(s)
- Helena Korres de Paula
- Division of Occupational and Environmental Medicine, Lund University, Lund 22185, Sweden
| | - Tanzy M Love
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA.
| | - Daniela Pineda
- Division of Occupational and Environmental Medicine, Lund University, Lund 22185, Sweden
| | - Gene E Watson
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Sally W Thurston
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Alison J Yeates
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Cromore Road, Coleraine BT52 1SA, Co. Londonderry, UK
| | - Maria S Mulhern
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Cromore Road, Coleraine BT52 1SA, Co. Londonderry, UK
| | - Emeir M McSorley
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Cromore Road, Coleraine BT52 1SA, Co. Londonderry, UK
| | - J J Strain
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Cromore Road, Coleraine BT52 1SA, Co. Londonderry, UK
| | | | - G J Myers
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Matthew D Rand
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Edwin van Wijngaarden
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Karin Broberg
- Division of Occupational and Environmental Medicine, Lund University, Lund 22185, Sweden; Institute of Environmental Medicine, Metals and Health, P.O. Box 210, Stockholm 17177, Sweden
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Bottini CLJ, MacDougall-Shackleton SA. Methylmercury effects on avian brains. Neurotoxicology 2023; 96:140-153. [PMID: 37059311 DOI: 10.1016/j.neuro.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 04/03/2023] [Accepted: 04/11/2023] [Indexed: 04/16/2023]
Abstract
Methylmercury (MeHg) is a concerning contaminant due to its ubiquity and harmful effects on organisms. Although birds are important models in the neurobiology of vocal learning and adult neuroplasticity, the neurotoxic effects of MeHg are less understood in birds than mammals. We surveyed the literature on MeHg effects on biochemical changes in the avian brain. Publication rates of papers related to neurology and/or birds and/or MeHg increased with time and can be linked with historical events, regulations, and increased understanding of MeHg cycling in the environment. However, publications on MeHg effects on the avian brain remain relatively low across time. The neural effects measured to evaluate MeHg neurotoxicity in birds changed with time and researcher interest. The measures most consistently affected by MeHg exposure in birds were markers of oxidative stress. NMDA, acetylcholinesterase, and Purkinje cells also seem sensitive to some extent. MeHg exposure has the potential to affect most neurotransmitter systems but more studies are needed for validation in birds. We also review the main mechanisms of MeHg-induced neurotoxicity in mammals and compare it to what is known in birds. The literature on MeHg effects on the avian brain is limited, preventing full construction of an adverse outcome pathway. We identify research gaps for taxonomic groups such as songbirds, and age- and life-stage groups such as immature fledgling stage and adult non-reproductive life stage. In addition, results are often inconsistent between experimental and field studies. We conclude that future neurotoxicological studies of MeHg impacts on birds need to better connect the numerous aspects of exposure from molecular physiological effects to behavioural outcomes that would be ecologically or biologically relevant for birds, especially under challenging conditions.
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Affiliation(s)
- Claire L J Bottini
- University of Western Ontario, Department of Biology, 1151 Richmond St., London Ontario, N6A 5B7; Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada.
| | - Scott A MacDougall-Shackleton
- Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada; University of Western Ontario, Department of Psychology, 1151 Richmond St., London Ontario, N6A 5C2
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Bose R, Spulber S, Ceccatelli S. The Threat Posed by Environmental Contaminants on Neurodevelopment: What Can We Learn from Neural Stem Cells? Int J Mol Sci 2023; 24:ijms24054338. [PMID: 36901772 PMCID: PMC10002364 DOI: 10.3390/ijms24054338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/03/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Exposure to chemicals may pose a greater risk to vulnerable groups, including pregnant women, fetuses, and children, that may lead to diseases linked to the toxicants' target organs. Among chemical contaminants, methylmercury (MeHg), present in aquatic food, is one of the most harmful to the developing nervous system depending on time and level of exposure. Moreover, certain man-made PFAS, such as PFOS and PFOA, used in commercial and industrial products including liquid repellants for paper, packaging, textile, leather, and carpets, are developmental neurotoxicants. There is vast knowledge about the detrimental neurotoxic effects induced by high levels of exposure to these chemicals. Less is known about the consequences that low-level exposures may have on neurodevelopment, although an increasing number of studies link neurotoxic chemical exposures to neurodevelopmental disorders. Still, the mechanisms of toxicity are not identified. Here we review in vitro mechanistic studies using neural stem cells (NSCs) from rodents and humans to dissect the cellular and molecular processes changed by exposure to environmentally relevant levels of MeHg or PFOS/PFOA. All studies show that even low concentrations dysregulate critical neurodevelopmental steps supporting the idea that neurotoxic chemicals may play a role in the onset of neurodevelopmental disorders.
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Bjørklund G, Antonyak H, Polishchuk A, Semenova Y, Lesiv M, Lysiuk R, Peana M. Effect of methylmercury on fetal neurobehavioral development: an overview of the possible mechanisms of toxicity and the neuroprotective effect of phytochemicals. Arch Toxicol 2022; 96:3175-3199. [PMID: 36063174 DOI: 10.1007/s00204-022-03366-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 08/17/2022] [Indexed: 11/25/2022]
Abstract
Methylmercury (MeHg) is a global environmental pollutant with neurotoxic effects. Exposure to MeHg via consumption of seafood and fish can severely impact fetal neurobehavioral development even when MeHg levels in maternal blood are as low as about 5 μg/L, which the mother tolerates well. Persistent motor dysfunctions and cognitive deficits may result from trans-placental exposure. The present review summarizes current knowledge on the mechanisms of MeHg toxicity during the period of nervous system development. Although cerebellar Purkinje cells are MeHg targets, the actions of MeHg on thiol components in the neuronal cytoskeleton as well as on mitochondrial enzymes and induction of disturbances of glutamate signaling can impair extra-cerebellar functions, also at levels well tolerated by adult individuals. Numerous herbal substances possess neuroprotective effects, predominantly represented by natural polyphenolic molecules that might be utilized to develop natural drugs to alleviate neurotoxicity symptoms caused by MeHg or other Hg compounds.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Toften 24, 8610, Mo i Rana, Norway.
| | | | | | | | - Marta Lesiv
- Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Roman Lysiuk
- Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
- CONEM Ukraine Life Science Research Group, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
| | - Massimiliano Peana
- Department of Chemical, Physics, Mathematics and Natural Sciences, University of Sassari, Sassari, Italy
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Mohammadi S, Shafiee M, Faraji SN, Rezaeian M, Ghaffarian-Bahraman A. Contamination of breast milk with lead, mercury, arsenic, and cadmium in Iran: a systematic review and meta-analysis. Biometals 2022; 35:711-728. [PMID: 35575819 DOI: 10.1007/s10534-022-00395-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/29/2022] [Indexed: 12/29/2022]
Abstract
Breast milk is a complete food for the development of the newborn, but it can also be an important route for environmental pollutants transmission to the infants. This study was aimed to evaluate the status of heavy metals including lead (Pb), mercury (Hg), cadmium (Cd) and arsenic (As) in the breast milk of Iranian mothers. The international databases including Scopus, PubMed, Web of Science and the Persian electronic databases including Scientific Information Database, IranMedex and Magiran were examined to find relevant articles published until July 2021. A total of 23 studies examined the levels of toxic metals in Iranian breast milk samples. According to the findings, the pooled average concentrations (µg/L) of Pb, Cd, Hg and As were 25.61, 2.40, 1.29 and 1.16, respectively. The concentration of Hg and Pb in colostrum milk was more than twice of mature milk. The Hg mean concentration in the breast milk of mothers with at least one amalgam-filled tooth was approximately three times that of mothers without amalgam-filled teeth. Risk assessment analysis indicated that the intake of Pb and Hg by infants through breastfeeding can be considered a health concern in Iran. It seems necessary to reduce the Pb exposure of pregnant and lactating women in Iran. However, more extensive studies are needed to clarify the toxic metals' exposure status of infants through breast milk in other parts of the country.
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Affiliation(s)
- Salman Mohammadi
- Nutritional Health Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Maryam Shafiee
- Nephro-Urology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyed Nooreddin Faraji
- School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohsen Rezaeian
- Department of Epidemiology and Biostatistics, Occupational Environment Research Center, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Ali Ghaffarian-Bahraman
- Occupational Environment Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
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Luz DA, Cartágenes SDC, da Silveira CCSDM, Pinheiro BG, Ferraro KMMM, Fernandes LDMP, Fontes-Júnior EA, Maia CDSF. Methylmercury plus Ethanol Exposure: How Much Does This Combination Affect Emotionality? Int J Mol Sci 2021; 22:ijms222313131. [PMID: 34884935 PMCID: PMC8658096 DOI: 10.3390/ijms222313131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 12/12/2022] Open
Abstract
Mercury is a heavy metal found in organic and inorganic forms that represents an important toxicant with impact on human health. Mercury can be released in the environment by natural phenoms (i.e., volcanic eruptions), industrial products, waste, or anthropogenic actions (i.e., mining activity). Evidence has pointed to mercury exposure inducing neurological damages related to emotional disturbance, such as anxiety, depression, and insomnia. The mechanisms that underlie these emotional disorders remain poorly understood, although an important role of glutamatergic pathways, alterations in HPA axis, and disturbance in activity of monoamines have been suggested. Ethanol (EtOH) is a psychoactive substance consumed worldwide that induces emotional alterations that have been strongly investigated, and shares common pathophysiological mechanisms with mercury. Concomitant mercury and EtOH intoxication occur in several regions of the world, specially by communities that consume seafood and fish as the principal product of nutrition (i.e., Amazon region). Such affront appears to be more deleterious in critical periods of life, such as the prenatal and adolescence period. Thus, this review aimed to discuss the cellular and behavioral changes displayed by the mercury plus EtOH exposure during adolescence, focused on emotional disorders, to answer the question of whether mercury plus EtOH exposure intensifies depression, anxiety, and insomnia observed by the toxicants in isolation.
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Affiliation(s)
- Diandra Araújo Luz
- Laboratório de Farmacologia da Inflamação e do Comportamento, Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (D.A.L.); (S.d.C.C.); (C.C.S.d.M.d.S.); (B.G.P.); (K.M.M.M.F.); (E.A.F.-J.)
| | - Sabrina de Carvalho Cartágenes
- Laboratório de Farmacologia da Inflamação e do Comportamento, Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (D.A.L.); (S.d.C.C.); (C.C.S.d.M.d.S.); (B.G.P.); (K.M.M.M.F.); (E.A.F.-J.)
| | - Cinthia Cristina Sousa de Menezes da Silveira
- Laboratório de Farmacologia da Inflamação e do Comportamento, Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (D.A.L.); (S.d.C.C.); (C.C.S.d.M.d.S.); (B.G.P.); (K.M.M.M.F.); (E.A.F.-J.)
| | - Bruno Gonçalves Pinheiro
- Laboratório de Farmacologia da Inflamação e do Comportamento, Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (D.A.L.); (S.d.C.C.); (C.C.S.d.M.d.S.); (B.G.P.); (K.M.M.M.F.); (E.A.F.-J.)
| | - Kissila Márvia Matias Machado Ferraro
- Laboratório de Farmacologia da Inflamação e do Comportamento, Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (D.A.L.); (S.d.C.C.); (C.C.S.d.M.d.S.); (B.G.P.); (K.M.M.M.F.); (E.A.F.-J.)
| | - Luanna de Melo Pereira Fernandes
- Departamento de Ciências Morfológicas e Fisiológicas, Centro das Ciências Biológicas e da Saúde (CCBS), Universidade Estadual do Pará, Belém 66095-100, PA, Brazil;
| | - Enéas Andrade Fontes-Júnior
- Laboratório de Farmacologia da Inflamação e do Comportamento, Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (D.A.L.); (S.d.C.C.); (C.C.S.d.M.d.S.); (B.G.P.); (K.M.M.M.F.); (E.A.F.-J.)
| | - Cristiane do Socorro Ferraz Maia
- Laboratório de Farmacologia da Inflamação e do Comportamento, Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (D.A.L.); (S.d.C.C.); (C.C.S.d.M.d.S.); (B.G.P.); (K.M.M.M.F.); (E.A.F.-J.)
- Correspondence:
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Tu R, Zhang C, Feng L, Wang H, Wang W, Li P. Impact of selenium on cerebellar injury and mRNA expression in offspring of rat exposed to methylmercury. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 223:112584. [PMID: 34365210 DOI: 10.1016/j.ecoenv.2021.112584] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/20/2021] [Accepted: 07/29/2021] [Indexed: 06/13/2023]
Abstract
During the fetal development stage, the Central Nervous System (CNS) is particularly sensitive to methylmercury (MeHg). However, the mechanism underlying the antagonistic effect of selenium (Se) on MeHg toxicity is still not fully understood. In this study, female rat models with MeHg and Se co-exposure were developed. Pathological changes in the cerebellum and differential mRNA expression profiles in offspring rats were studied. In the MeHg-exposed group, a large number of Purkinje cells showed pathological changes and mitochondria were significantly swollen; co-exposure with Se significantly improved the structure and organization of the cerebellum. In total, 378 differentially expressed genes (DEGs) (including 284 up-regulated genes and 94 down-regulated genes) in the cerebellum of the MeHg-exposed group and 210 DEGs (including 84 up-regulated genes and 126 down-regulated genes) in the cerebellum of the MeHg+Se co-exposed group were identified. The genes involved in neurotransmitter synthesis and release and calcium ion balance in the cerebellum were significantly up-regulated in the MeHg-exposed group. These genes in the MeHg+Se co-exposed group were not changed or down-regulated. These findings demonstrate that the neurotoxicity caused by MeHg exposure is related to the up-regulation of multiple genes in the nerve signal transduction and calcium ion signal pathways, which are closely related to impairments in cell apoptosis and learning and memory. Supplementation with Se can mitigate the changes to related genes and protect neurons in the mammalian brain (especially the developing cerebellum) from MeHg toxicity. Se provides a potential intervention strategy for MeHg toxicity.
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Affiliation(s)
- Rui Tu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; Key Laboratory of Environmental Pollution Monitoring and Disease Control/School of Public Health, Guizhou Medical University, Guiyang 550025, China; Division of Infection Management, Guiyang First People's Hospital, Guiyang 550000, China
| | - Chanchan Zhang
- Key Laboratory of Environmental Pollution Monitoring and Disease Control/School of Public Health, Guizhou Medical University, Guiyang 550025, China
| | - Ling Feng
- Key Laboratory of Environmental Pollution Monitoring and Disease Control/School of Public Health, Guizhou Medical University, Guiyang 550025, China
| | - Huiqun Wang
- Key Laboratory of Environmental Pollution Monitoring and Disease Control/School of Public Health, Guizhou Medical University, Guiyang 550025, China
| | - Wenjuan Wang
- Key Laboratory of Environmental Pollution Monitoring and Disease Control/School of Public Health, Guizhou Medical University, Guiyang 550025, China.
| | - Ping Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
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He B, Wang Y, Li S, Zhao Y, Ma X, Wang W, Li X, Zhang Y. A cross-sectional survey of preschool children: Exploring heavy metal exposure, neurotransmitters, and neurobehavioural relationships and mediation effects. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 220:112391. [PMID: 34090107 DOI: 10.1016/j.ecoenv.2021.112391] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/23/2021] [Accepted: 05/28/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Exposure to heavy metals has been considered harmful and can cause cognitive deficits in preschool children. OBJECTIVE To investigate the possible mediation effect of neurotransmitters on the relationship of heavy metal exposure with neurobehaviour. METHODS The levels of blood heavy metals and neurotransmitters, along with the neurobehavioural scores, were determined in preschool children. Multiple linear regression was used to assess the relationship between heavy metals, neurotransmitters, and neurobehavioural scores. Furthermore, the mediating role of neurotransmitters was investigated. RESULTS An interquartile range (IQR) increase in lead (6.10 μg/L) was associated with a decrease of 8.52%, 30.06%, and 20.10% for Glutamic acid (Glu), Glycine (Gly), and gamma-aminobutyric acid (GABA), respectively. An IQR increase in arsenic (19.37 μg/L) was associated with an increase of 6.32% and 2.09% for Gly and GABA, respectively. Further, an IQR increase in zinc (15.58 μg/L) was associated with an increase of 1.44% for Ser, whereas the IQR increase was associated with a decrease of 2.14%, 2.24%, and 1.89% for Glu, Gly, and GABA, respectively. An IQR increase in selenium (38.75 μg/L) was associated with an increase of 1.88% for GABA. Moreover, both Glu and Gly decreased by 2.87% for an IQR increase in manganese (16.92 μg/L). An IQR increase in mercury (15.22 μg/L) was associated with a decrease of 2.43% for Ser, but the IQR increase was associated with an increase of 4.99% and 3.09% for Gly and GABA, respectively. It was found that Glu and Serine (Ser) have a significant linear relationship with conduct score and impulsivity-hyperactivity index, and that there was a significant linear relationship between Ser and the learning disability index. GABA and conduct score and attention-deficit hyperactivity disorder (ADHD) index have a significant linear relationship. There is a significant linear relationship between Gly and conduct, anxiety, ADHD, and impulsivity-hyperactivity index. The results of the mediating effect analysis indicated that Ser, Glu, Gly, and GABA have a specific mediating effect between blood heavy metals and neurobehaviour. CONCLUSION We showed the mediating effect of neurotransmitters. The current study may provide valuable information regarding the prevention and management of metal-related neurological disorders in preschool children.
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Affiliation(s)
- Bin He
- School of Public Health, North China University of Science and Technology, 21 Bohai Road, Cao Fei Dian, Tangshan, Hebei 063210, China; The Laboratory Animal Center, North China University of Science and Technology, 21 Bohai Road, Cao Fei Dian, Tangshan, Hebei 063210, China
| | - Yan Wang
- Special Medical Service Teaching and Research Section, Tactical Medical Service Department, Army Medical University NCO School, Shijia Zhuang 050051, China
| | - Shuang Li
- The Laboratory Animal Center, North China University of Science and Technology, 21 Bohai Road, Cao Fei Dian, Tangshan, Hebei 063210, China
| | - Yuwei Zhao
- School of Public Health, North China University of Science and Technology, 21 Bohai Road, Cao Fei Dian, Tangshan, Hebei 063210, China
| | - Xiaolong Ma
- The Laboratory Animal Center, North China University of Science and Technology, 21 Bohai Road, Cao Fei Dian, Tangshan, Hebei 063210, China
| | - Weicheng Wang
- School of Public Health, North China University of Science and Technology, 21 Bohai Road, Cao Fei Dian, Tangshan, Hebei 063210, China
| | - Xinran Li
- School of Public Health, North China University of Science and Technology, 21 Bohai Road, Cao Fei Dian, Tangshan, Hebei 063210, China
| | - Yanshu Zhang
- School of Public Health, North China University of Science and Technology, 21 Bohai Road, Cao Fei Dian, Tangshan, Hebei 063210, China; The Laboratory Animal Center, North China University of Science and Technology, 21 Bohai Road, Cao Fei Dian, Tangshan, Hebei 063210, China.
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Hurtado-Díaz M, Riojas-Rodríguez H, Rothenberg SJ, Schnaas-Arrieta L, Kloog I, Just A, Hernández-Bonilla D, Wright RO, Téllez-Rojo MM. Prenatal PM 2.5 exposure and neurodevelopment at 2 years of age in a birth cohort from Mexico city. Int J Hyg Environ Health 2021; 233:113695. [PMID: 33582606 DOI: 10.1016/j.ijheh.2021.113695] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 01/02/2023]
Abstract
BACKGROUND Recent studies have reported that air pollution exposure may have neurotoxic properties. OBJECTIVE To examine longitudinal associations between prenatal particles less than 2.5 μm in diameter (PM2.5) exposure and neurodevelopment during the first two years of children's life. METHODS Analysis was conducted in PROGRESS, a longitudinal birth cohort between 2007 and 2013 in Mexico City. We used satellite data to predict daily PM2.5 concentrations at high spatial resolution. Multivariate mixed-effect regression models were adjusted to examine cognitive, language and motor scores in children up to 24 months of age (n = 740) and each trimester-specific and whole pregnancy exposure to PM2.5. RESULTS Models adjusted by child sex, gestational age, birth weight, smoking and mother's IQ, showed that each increase of 1 μg/m3 of PM2.5 was associated with a decreased language function of -0.38 points (95% CI: -0.77, -0.01). PM2.5 exposure at third trimester of pregnancy contributed most to the observed association. CONCLUSION Our findings suggest that language development up to 24 months of age may be particularly sensitive to PM2.5 exposure during pregnancy.
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Affiliation(s)
- Magali Hurtado-Díaz
- Center for Population Health Research, National Institute of Public Health, Av. Universidad No. 655, Col. Sta. Ma. Ahuacatitlán, 62100, Cuernavaca, Morelos, Mexico.
| | - Horacio Riojas-Rodríguez
- Center for Population Health Research, National Institute of Public Health, Av. Universidad No. 655, Col. Sta. Ma. Ahuacatitlán, 62100, Cuernavaca, Morelos, Mexico.
| | - Stephen J Rothenberg
- Center for Population Health Research, National Institute of Public Health, Av. Universidad No. 655, Col. Sta. Ma. Ahuacatitlán, 62100, Cuernavaca, Morelos, Mexico.
| | - Lourdes Schnaas-Arrieta
- Department of Developmental Neurobiology, National Institute of Perinatology, Montes Urales 800 Col. Virreyes Deleg, Miguel Hidalgo D.F, C.P. 11000, USA.
| | - Itai Kloog
- Department of Geography and Environmental Development, Ben-Gurion University of the Negev (BGU), Beer Sheva, Israel.
| | - Allan Just
- Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, 17 East 102 Street, Floor 3, Room 131, New York, NY, 10029, USA.
| | - David Hernández-Bonilla
- Center for Population Health Research, National Institute of Public Health, Av. Universidad No. 655, Col. Sta. Ma. Ahuacatitlán, 62100, Cuernavaca, Morelos, Mexico.
| | - Robert O Wright
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, 17 East 102 Street Floor 3 West Room D3-110, New York, 10029, NY, USA.
| | - Martha Ma Téllez-Rojo
- Center for Nutrition and Health Research, National Institute of Public Health, Av. Universidad No. 655, Col. Sta. Ma. Ahuacatitlán, 61200, Cuernavaca, Morelos, Mexico.
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10
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Ijomone OM, Ijomone OK, Iroegbu JD, Ifenatuoha CW, Olung NF, Aschner M. Epigenetic influence of environmentally neurotoxic metals. Neurotoxicology 2020; 81:51-65. [PMID: 32882300 PMCID: PMC7708394 DOI: 10.1016/j.neuro.2020.08.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 08/25/2020] [Accepted: 08/25/2020] [Indexed: 02/08/2023]
Abstract
Continuous globalization and industrialization have ensured metals are an increasing aspect of daily life. Their usefulness in manufacturing has made them vital to national commerce, security and global economy. However, excess exposure to metals, particularly as a result of environmental contamination or occupational exposures, has been detrimental to overall health. Excess exposure to several metals is considered environmental risk in the aetiology of several neurological and neurodegenerative diseases. Metal-induced neurotoxicity has been a major health concern globally with intensive research to unravel the mechanisms associated with it. Recently, greater focus has been directed at epigenetics to better characterize the underlying mechanisms of metal-induced neurotoxicity. Epigenetic changes are those modifications on the DNA that can turn genes on or off without altering the DNA sequence. This review discusses how epigenetic changes such as DNA methylation, post translational histone modification and noncoding RNA-mediated gene silencing mediate the neurotoxic effects of several metals, focusing on manganese, arsenic, nickel, cadmium, lead, and mercury.
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Affiliation(s)
- Omamuyovwi M Ijomone
- The Neuro- Lab, Department of Human Anatomy, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria.
| | - Olayemi K Ijomone
- The Neuro- Lab, Department of Human Anatomy, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria; Department of Anatomy, University of Medical Sciences, Ondo, Nigeria
| | - Joy D Iroegbu
- The Neuro- Lab, Department of Human Anatomy, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria
| | - Chibuzor W Ifenatuoha
- The Neuro- Lab, Department of Human Anatomy, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria
| | - Nzube F Olung
- The Neuro- Lab, Department of Human Anatomy, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria
| | - Michael Aschner
- Departments of Molecular Pharmacology and Neurosciences, Albert Einstein College of Medicine, NY, USA.
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11
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Rahman MA, Rahman MS, Uddin MJ, Mamum-Or-Rashid ANM, Pang MG, Rhim H. Emerging risk of environmental factors: insight mechanisms of Alzheimer's diseases. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:44659-44672. [PMID: 32201908 DOI: 10.1007/s11356-020-08243-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/25/2020] [Indexed: 06/10/2023]
Abstract
Neurodegenerative disorders are typically sporadic in nature in addition to usually influenced through an extensive range of environmental factors, lifestyle, and genetic elements. Latest observations have hypothesized that exposure of environmental factors may increase the prospective risk of Alzheimer's diseases (AD). However, the role of environmental factors as a possible dangerous issue has extended importance concerned in AD pathology, although actual etiology of the disorder is still not yet clear. Thus, the aim of this review is to highlight the possible correlation between environmental factors and AD, based on the present literature view. Environmental risk factors might play an important role in decelerating or accelerating AD progression. Among well-known environmental risk factors, prolonged exposure to several heavy metals, for example, aluminum, arsenic, cadmium, lead, and mercury; particulate air, and some pesticides as well as metal-containing nanoparticles have been participated to cause AD. These heavy metals have the capacity to enhance amyloid β (Aβ) peptide along with tau phosphorylation, initiating amyloid/senile plaques, as well as neurofibrillary tangle formation; therefore, neuronal cell death has been observed. Furthermore, particulate air, pesticides, and heavy metal exposure have been recommended to lead AD susceptibility and phenotypic diversity though epigenetic mechanisms. Therefore, this review deliberates recent findings detailing the mechanisms for a better understanding the relationship between AD and environmental risk factors along with their mechanisms of action on the brain functions.
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Affiliation(s)
- Md Ataur Rahman
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea.
- Department of Biotechnology and Genetic Engineering, Global Biotechnology & Biomedical Research Network (GBBRN), Faculty of Biological Sciences, Islamic University, Kushtia, 7003, Bangladesh.
| | - Md Saidur Rahman
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong, 456-756, Republic of Korea
| | - Md Jamal Uddin
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, 03760, Republic of Korea
- ABEx Bio-Research Center, East Azampur, Dhaka, 1230, Bangladesh
| | - A N M Mamum-Or-Rashid
- Anti-Aging Medical Research Center and Glycation Stress Research Center, Graduate School of Life and Medical Sciences, Doshisha University, Kyoto, Japan
| | - Myung-Geol Pang
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong, 456-756, Republic of Korea
| | - Hyewhon Rhim
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea.
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea.
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12
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Kanwar VS, Sharma A, Srivastav AL, Rani L. Phytoremediation of toxic metals present in soil and water environment: a critical review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:44835-44860. [PMID: 32981020 DOI: 10.1007/s11356-020-10713-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 09/01/2020] [Indexed: 06/11/2023]
Abstract
Heavy metals are one of the most hazardous inorganic contaminants of both water and soil environment composition. Normally, heavy metals are non-biodegradable in nature because of their long persistence in the environment. Trace amounts of heavy metal contamination may pose severe health problems in human beings after prolonged consumption. Many instrumental techniques such as atomic absorption spectrophotometry, inductively coupled plasma-mass spectrometry, X-ray fluorescence, neutron activation analysis, etc. have been developed to determine their concentration in water as well as in the soil up to ppm, ppb, or ppt levels. Recent advances in these techniques along with their respective advantages and limitations are being discussed in the present paper. Moreover, some possible remedial phytoremediation approaches (phytostimulation, phytoextraction, phyotovolatilization, rhizofiltration, phytostabilization) have been presented for the removal of the heavy metal contamination from the water and soil environments.
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Affiliation(s)
- Varinder Singh Kanwar
- Chitkara University School of Engineering and Technology, Chitkara University, Solan, Himachal Pradesh, 174103, India
| | - Ajay Sharma
- Chitkara University School of Engineering and Technology, Chitkara University, Solan, Himachal Pradesh, 174103, India
| | - Arun Lal Srivastav
- Chitkara University School of Engineering and Technology, Chitkara University, Solan, Himachal Pradesh, 174103, India.
| | - Lata Rani
- School of Basic Sciences, Chitkara University, Solan, Himachal Pradesh, 174103, India
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13
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Mir RH, Sawhney G, Pottoo FH, Mohi-Ud-Din R, Madishetti S, Jachak SM, Ahmed Z, Masoodi MH. Role of environmental pollutants in Alzheimer's disease: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:44724-44742. [PMID: 32715424 DOI: 10.1007/s11356-020-09964-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
Neurodegenerative disorders are commonly erratic influenced by various factors including lifestyle, environmental, and genetic factors. In recent observations, it has been hypothesized that exposure to various environmental factors enhances the risk of Alzheimer's disease (AD). The exact etiology of Alzheimer's disease is still unclear; however, the contribution of environmental factors in the pathology of AD is widely acknowledged. Based on the available literature, the review aims to culminate in the prospective correlation between the various environmental factors and AD. The prolonged exposure to the various well-known environmental factors including heavy metals, air pollutants (particulate matter), pesticides, nanoparticles containing metals, industrial chemicals results in accelerating the progression of AD. Common mechanisms have been documented in the field of environmental contaminants for enhancing amyloid-β (Aβ) peptide along with tau phosphorylation, resulting in the initiation of senile plaques and neurofibrillary tangles, which results in the death of neurons. This review offers a compilation of available data to support the long-suspected correlation between environmental risk factors and AD pathology. Graphical abstract .
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Affiliation(s)
- Reyaz Hassan Mir
- Pharmaceutical Chemistry Division, Department of Pharmaceutical Sciences, University of Kashmir, Hazratbal, Srinagar, Kashmir, 190006, India.
| | - Gifty Sawhney
- Inflammation Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu-Tawi, Jammu, 180001, India
| | - Faheem Hyder Pottoo
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O.BOX 1982, Dammam, 31441, Saudi Arabia
| | - Roohi Mohi-Ud-Din
- Pharmacognosy Division, Department of Pharmaceutical Sciences, University of Kashmir, Hazratbal, Srinagar, Kashmir, 190006, India
| | - Sreedhar Madishetti
- Inflammation Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu-Tawi, Jammu, 180001, India
| | - Sanjay M Jachak
- Department of Natural Products, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, SAS Nagar, Mohali, Punjab, 160062, India
| | - Zabeer Ahmed
- Inflammation Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu-Tawi, Jammu, 180001, India
| | - Mubashir Hussain Masoodi
- Pharmaceutical Chemistry Division, Department of Pharmaceutical Sciences, University of Kashmir, Hazratbal, Srinagar, Kashmir, 190006, India.
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14
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Feng L, Zhang C, Liu H, Li P, Hu X, Wang H, Chan HM, Feng X. Impact of low-level mercury exposure on intelligence quotient in children via rice consumption. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 202:110870. [PMID: 32593806 DOI: 10.1016/j.ecoenv.2020.110870] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/27/2020] [Accepted: 06/06/2020] [Indexed: 06/11/2023]
Abstract
Wanshan is a city in southwest China that has several inactive mercury (Hg) mines. The local population are exposed to methylmercury (MeHg) due to the consumption of Hg contaminated rice. The relationship between Hg exposure and the cognitive functions of local children is unknown. This study investigated the relationship between hair Hg concentrations and the intelligence quotient (IQ) of 314 children aged 8-10 years, recruited from three local primary schools in Wanshan area in 2018 and 2019. IQ was evaluated using Wechsler Intelligence Scale for Children - Fourth Edition (WISC-IV). The average THg concentration in children's hair samples was 1.53 μg g-1 (range: 0.21-12.6 μg g-1), and 65.6% exceeded the United States Environment Protection Agency (USEPA) recommended value of 1 μg g-1. Results of logistic regression analysis showed that children with hair Hg ≥ 1 μg g-1 were 1.58 times more likely to have an IQ score <80, which is the clinical cut-off for borderline intellectual disability (R2 = 0.20, p = 0.03). Increasing of 1 μg g-1 hair Hg resulted in 1 point of IQ loss in Wanshan children, which was.much higher than that via fish consumption. The economical cost due to Hg exposure was estimated to be $69.8 million (9.43% of total GDP) in the Wanshan area in 2018.
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Affiliation(s)
- Lin Feng
- School of Public Health/Key Laboratory of Environmental Pollution Monitoring and Disease Control, Guizhou Medical University, Guiyang, 550025, China
| | - Chanchan Zhang
- School of Public Health/Key Laboratory of Environmental Pollution Monitoring and Disease Control, Guizhou Medical University, Guiyang, 550025, China
| | - Haohao Liu
- School of Public Health/Key Laboratory of Environmental Pollution Monitoring and Disease Control, Guizhou Medical University, Guiyang, 550025, China
| | - Ping Li
- School of Public Health/Key Laboratory of Environmental Pollution Monitoring and Disease Control, Guizhou Medical University, Guiyang, 550025, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Xuefeng Hu
- Department of Biology, University of Ottawa, Ottawa, K1N 6N5, Canada
| | - Huiqun Wang
- School of Public Health/Key Laboratory of Environmental Pollution Monitoring and Disease Control, Guizhou Medical University, Guiyang, 550025, China
| | - Hing Man Chan
- Department of Biology, University of Ottawa, Ottawa, K1N 6N5, Canada
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
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15
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Aaseth J, Wallace DR, Vejrup K, Alexander J. Methylmercury and developmental neurotoxicity: A global concern. CURRENT OPINION IN TOXICOLOGY 2020. [DOI: 10.1016/j.cotox.2020.01.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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16
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Novirsa R, Dinh QP, Jeong H, Addai-Arhin S, Nugraha WC, Hirota N, Wispriyono B, Ishibashi Y, Arizono K. The dietary intake of mercury from rice and human health risk in artisanal small-scale gold mining area, Indonesia. ACTA ACUST UNITED AC 2020. [DOI: 10.2131/fts.7.215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Randy Novirsa
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
| | - Quang Phan Dinh
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
| | - Huiho Jeong
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
| | - Sylvester Addai-Arhin
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
| | - Willy Cahya Nugraha
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
| | - Nana Hirota
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
| | - Bambang Wispriyono
- Department of Environmental Health, Faculty of Public Health, University of Indonesia
| | - Yasuhiro Ishibashi
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
| | - Koji Arizono
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
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17
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Methylmercury Epigenetics. TOXICS 2019; 7:toxics7040056. [PMID: 31717489 PMCID: PMC6958348 DOI: 10.3390/toxics7040056] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/22/2019] [Accepted: 11/05/2019] [Indexed: 12/12/2022]
Abstract
Methylmercury (MeHg) has conventionally been investigated for effects on nervous system development. As such, epigenetic modifications have become an attractive mechanistic target, and research on MeHg and epigenetics has rapidly expanded in the past decade. Although, these inquiries are a recent advance in the field, much has been learned in regards to MeHg-induced epigenetic modifications, particularly in the brain. In vitro and in vivo controlled exposure studies illustrate that MeHg effects microRNA (miRNA) expression, histone modifications, and DNA methylation both globally and at individual genes. Moreover, some effects are transgenerationally inherited, as organisms not directly exposed to MeHg exhibited biological and behavioral alterations. miRNA expression generally appears to be downregulated consequent to exposure. Further, global histone acetylation also seems to be reduced, persist at distinct gene promoters, and is contemporaneous with enhanced histone methylation. Moreover, global DNA methylation appears to decrease in brain-derived tissues, but not in the liver; however, selected individual genes in the brain are hypermethylated. Human epidemiological studies have also identified hypo- or hypermethylated individual genes, which correlated with MeHg exposure in distinct populations. Intriguingly, several observed epigenetic modifications can be correlated with known mechanisms of MeHg toxicity. Despite this knowledge, however, the functional consequences of these modifications are not entirely evident. Additional research will be necessary to fully comprehend MeHg-induced epigenetic modifications and the impact on the toxic response.
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18
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Krishna Chandran AM, Christina H, Das S, Mumbrekar KD, Satish Rao BS. Neuroprotective role of naringenin against methylmercury induced cognitive impairment and mitochondrial damage in a mouse model. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2019; 71:103224. [PMID: 31376681 DOI: 10.1016/j.etap.2019.103224] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/09/2019] [Accepted: 07/21/2019] [Indexed: 06/10/2023]
Abstract
Human exposure to organomercurials like methylmercury (MeHg) may occur by consumption of contaminated seafood, affecting various vital organs especially, brain contributing to neuro disorders. The citrus flavanone, naringenin (NAR) has shown strong antioxidant and anti-inflammatory effects and therefore may exert cytoprotective effect against xenobiotic agents. Herein, we investigated the neuroprotective role of NAR against MeHg induced functional changes in mitochondria, neuronal cell death and cognitive impairment in a mouse model. A neurotoxic dose of MeHg (4 mg/kg.b.wt.) was administered orally to mice for 15 days. This resulted in the reduction of GSH and GST, an increase in mitochondrial DNA damage and memory impairment. On the contrary, NAR pre-treatment (100 mg/kg.b.wt.), helped in lowering the oxidative burden which in turn maintained mitochondrial function and prevented induced neuronal cell death, ultimately improving the cognitive impairment. As MeHg intoxication occurs chronically, consumption of the dietary components rich in NAR may have its positive human health impact, ultimately improving the quality of life.
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Affiliation(s)
- Adwaid Manu Krishna Chandran
- Department of Radiation Biology & Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, 576 104, Karnataka, India
| | - Hannah Christina
- Department of Radiation Biology & Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, 576 104, Karnataka, India
| | - Shubhankar Das
- Department of Radiation Biology & Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, 576 104, Karnataka, India
| | - Kamalesh D Mumbrekar
- Department of Radiation Biology & Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, 576 104, Karnataka, India
| | - B S Satish Rao
- Department of Radiation Biology & Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, 576 104, Karnataka, India.
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19
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Reardon AJF, Karathra J, Ribbenstedt A, Benskin JP, MacDonald AM, Kinniburgh DW, Hamilton TJ, Fouad K, Martin JW. Neurodevelopmental and Metabolomic Responses from Prenatal Coexposure to Perfluorooctanesulfonate (PFOS) and Methylmercury (MeHg) in Sprague-Dawley Rats. Chem Res Toxicol 2019; 32:1656-1669. [PMID: 31340646 DOI: 10.1021/acs.chemrestox.9b00192] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Methylmercury (MeHg) and perfluorooctanesulfonate (PFOS) are major contaminants of human blood that are both common in dietary fish, thereby raising questions about their combined impact on human development. Here, pregnant Sprague-Dawley rats ingested a daily dose, from gestational day 1 through to weaning, of either 1 mg/kg bw PFOS (PFOS-only), 1 mg/kg MeHg (MeHg-only), a mixture of 0.1 mg/kg PFOS and 1 mg/kg MeHg (Low-Mix), or of 1 mg/kg of PFOS and 1 mg/kg MeHg (High-Mix). Newborns were monitored for physical milestones and reflexive developmental responses, and in juveniles the spontaneous activity, anxiety, memory, and cognition were assessed. Targeted metabolomics of 199 analytes was applied to sectioned brain regions of juvenile offspring. Newborns in the High-Mix group had decreased weight gain as well as delayed reflexes and innate behavioral responses compared to controls and individual chemical groups indicating a toxicological interaction on early development. In juveniles, cumulative mixture effects increased in a dose-dependent manner in tests of anxiety-like behavior. However, other developmental test results suggested antagonism, as PFOS-only and MeHg-only juveniles had increased hyperactivity and thigmotaxic behavior, respectively, but fewer effects in Low-Mix and High-Mix groups. Consistent with these behavioral observations, a pattern of antagonism was also observed in neurochemicals measured in rat cortex, as PFOS-only and MeHg-only juveniles had altered concentrations of metabolites (e.g., lipids, amino acids, and biogenic amines), while no changes were evident in the combined exposures. The cortical metabolites altered in PFOS-only and MeHg-only exposed groups are involved in inhibitory and excitatory neurotransmission. These proof-of-principle findings at relatively high doses indicate the potential for toxicological interaction between PFOS and MeHg, with developmental-stage specific effects. Future mixture studies at lower doses are warranted, and prospective human birth cohorts should consider possible confounding effects from PFOS and mercury exposure on neurodevelopment.
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Affiliation(s)
- Anthony J F Reardon
- Department of Laboratory Medicine and Pathology , University of Alberta , Edmonton , Alberta T6G 2G3 , Canada
| | - Jacqueline Karathra
- Department of Laboratory Medicine and Pathology , University of Alberta , Edmonton , Alberta T6G 2G3 , Canada
| | - Anton Ribbenstedt
- Department of Environmental Science and Analytical Chemistry (ACES) , Stockholm University , Stockholm SE-11418 , Sweden
| | - Jonathan P Benskin
- Department of Environmental Science and Analytical Chemistry (ACES) , Stockholm University , Stockholm SE-11418 , Sweden
| | - Amy M MacDonald
- Alberta Centre for Toxicology , University of Calgary , Calgary , Alberta T2N 1N4 , Canada
| | - David W Kinniburgh
- Alberta Centre for Toxicology , University of Calgary , Calgary , Alberta T2N 1N4 , Canada
| | - Trevor J Hamilton
- Department of Psychology , MacEwan University , Edmonton , Alberta T5J 4S2 , Canada
| | - Karim Fouad
- Department of Physical Therapy , University of Alberta , Edmonton , Alberta T6G 2G4 , Canada
| | - Jonathan W Martin
- Department of Laboratory Medicine and Pathology , University of Alberta , Edmonton , Alberta T6G 2G3 , Canada.,Department of Environmental Science and Analytical Chemistry (ACES) , Stockholm University , Stockholm SE-11418 , Sweden
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20
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Chung YP, Yen CC, Tang FC, Lee KI, Liu SH, Wu CC, Hsieh SS, Su CC, Kuo CY, Chen YW. Methylmercury exposure induces ROS/Akt inactivation-triggered endoplasmic reticulum stress-regulated neuronal cell apoptosis. Toxicology 2019; 425:152245. [PMID: 31330229 DOI: 10.1016/j.tox.2019.152245] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/06/2019] [Accepted: 07/15/2019] [Indexed: 12/13/2022]
Abstract
Epidemiological studies have positively linked mercury exposure and neurodegenerative diseases (ND). Methylmercury (MeHg), an organic form of mercury, is a ubiquitous and potent environmental neurotoxicant that easily crosses the blood-brain barrier and causes irreversible injury to the central nervous system (CNS). However, the molecular mechanisms underlying MeHg-induced neurotoxicity remain unclear. Here, the present study found that Neuro-2a cells underwent apoptosis in response to MeHg (1-5 μM), which was accompanied by increased phosphatidylserine (PS) exposure on the outer cellular membrane leaflets, caspase-3 activity, and the activation of caspase cascades and poly (ADP-ribose) polymerase (PARP). Exposure of Neuro-2a cells to MeHg also triggered endoplasmic reticulum (ER) stress, which was identified via several key molecules (including: glucose-regulated protein (GRP)78, GRP94, C/EBP homologous protein (CHOP) X-box binding protein(XBP)-1, protein kinase R-like ER kinase (PERK), eukaryotic initiation factor 2α (eIF2α), inositol-requiring enzyme(IRE)-1, activation transcription factor(AFT)4, and ATF6. Transfection with GRP78-, GRP94-, CHOP-, and XBP-1-specific small interfering (si)RNA significantly suppressed the expression of these proteins, and attenuated cytotoxicity and caspase-12, -7, and -3 activation in MeHg-exposed cells. Furthermore, MeHg dramatically decreased Akt phosphorylation, and the overexpression of activation of Akt1 (myr-Akt1) could significantly prevent MeHg-induced Akt inactivation, as well as apoptotic and ER stress-related signals. Pretreatment with the antioxidant N-acetylcysteine (NAC) effectively prevented MeHg-induced neuronal cell reactive oxygen species (ROS) generation, apoptotic and ER stress-related signals, and Akt inactivation. Collectively, these results indicate that MeHg exerts its cytotoxicity in neurons by inducing ROS-mediated Akt inactivation up-regulated ER stress, which induces apoptosis and ultimately leads to cell death.
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Affiliation(s)
- Yao-Pang Chung
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei 100, Taiwan; Department of Occupational Safety and Health, College of Health Care and Management, Chung Shan Medical University, Taichung, 402, Taiwan
| | - Cheng-Chieh Yen
- Department of Occupational Safety and Health, College of Health Care and Management, Chung Shan Medical University, Taichung, 402, Taiwan; Department of Occupational Medicine, Chung Shan Medical University Hospital, Taichung, 402, Taiwan
| | - Feng-Cheng Tang
- Department of Occupational Medicine, Changhua Christian Hospital, Changhua County, 500, Taiwan; Department of Leisure Services Management, Chaoyang University of Technology, Taichung, 413, Taiwan
| | - Kuan-I Lee
- Department of Emergency, Taichung Tzuchi Hospital, The Buddhist Tzuchi Medical Foundation, Taichung, 427, Taiwan
| | - Shing-Hwa Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chin-Ching Wu
- Department of Public Health, China Medical University, Taichung, 404, Taiwan
| | - Shang-Shu Hsieh
- Department of Emergency, Taichung Tzuchi Hospital, The Buddhist Tzuchi Medical Foundation, Taichung, 427, Taiwan
| | - Chin-Chuan Su
- Department of Otorhinolaryngology, Head and Neck Surgery, Changhua Christian Hospital, Changhua County 500, Taiwan
| | - Chun-Ying Kuo
- Department of Otorhinolaryngology, Head and Neck Surgery, Changhua Christian Hospital, Changhua County 500, Taiwan
| | - Ya-Wen Chen
- Department of Physiology and Graduate Institute of Basic Medical Science, School of Medicine, College of Medicine, China Medical University, Taichung 404, Taiwan.
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21
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Raciti M, Salma J, Spulber S, Gaudenzi G, Khalajzeyqami Z, Conti M, Anderlid BM, Falk A, Hermanson O, Ceccatelli S. NRXN1 Deletion and Exposure to Methylmercury Increase Astrocyte Differentiation by Different Notch-Dependent Transcriptional Mechanisms. Front Genet 2019; 10:593. [PMID: 31316548 PMCID: PMC6610538 DOI: 10.3389/fgene.2019.00593] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 06/05/2019] [Indexed: 01/11/2023] Open
Abstract
Controversial evidence points to a possible involvement of methylmercury (MeHg) in the etiopathogenesis of autism spectrum disorders (ASD). In the present study, we used human neuroepithelial stem cells from healthy donors and from an autistic patient bearing a bi-allelic deletion in the gene encoding for NRXN1 to evaluate whether MeHg would induce cellular changes comparable to those seen in cells derived from the ASD patient. In healthy cells, a subcytotoxic concentration of MeHg enhanced astroglial differentiation similarly to what observed in the diseased cells (N1), as shown by the number of GFAP positive cells and immunofluorescence signal intensity. In both healthy MeHg-treated and N1 untreated cells, aberrations in Notch pathway activity seemed to play a critical role in promoting the differentiation toward glia. Accordingly, treatment with the established Notch inhibitor DAPT reversed the altered differentiation. Although our data are not conclusive since only one of the genes involved in ASD is considered, the results provide novel evidence suggesting that developmental exposure to MeHg, even at subcytotoxic concentrations, induces alterations in astroglial differentiation similar to those observed in ASD.
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Affiliation(s)
- Marilena Raciti
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Jahan Salma
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Stefan Spulber
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Giulia Gaudenzi
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | | | - Mirko Conti
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Britt-Marie Anderlid
- Centre for Molecular Medicine, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Anna Falk
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ola Hermanson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Sandra Ceccatelli
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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22
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Jacob S, Sumathi T. Extenuation of in utero toxic effects of MeHg in the developing neurons by Fisetin via modulating the expression of synaptic transmission and plasticity regulators in hippocampus of the rat offspring. Chem Biol Interact 2019; 305:3-10. [PMID: 30890323 DOI: 10.1016/j.cbi.2019.03.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/13/2019] [Indexed: 12/27/2022]
Abstract
The neurotoxic environmental contaminant, methylmercury (MeHg), has shown to have detrimental effects on the developing brain when exposed during gestation. We have shown in our earlier studies that gestational administration of 3,3',4',7-Tetrahydroxyflavone or Fisetin reduces the toxic effects of MeHg in the developing rat brain. The current study has pivoted to study the mechanism behind the mitigating action of Fisetin against prenatal MeHg exposure induced neurotoxicity. Negligible data is available about the toxicity targets of MeHg in the developing brain. Studies have exhibited that MeHg exposure cause toxic effects on synaptic transmission and plasticity in the offspring brain. Hence, we aimed to study the effect of Fisetin on MeHg induced alterations in the expressions of regulatory genes and proteins involved in synaptic plasticity and transmission. Pregnant rats were grouped according to the type of oral administration as, (i) Control, (ii) MeHg (1.5 mg/kg b. w.), (iii) MeHg + Fisetin (30 mg/kg b. w.) and (iv) Fisetin (30 mg/kg b. w). Maternal administration of Fisetin prevented MeHg exposure induced downregulation of neurogranin (Nrgn), dendrin (Ddn), Syntaxin 1 A (Stx1a), Lin-7 homolog A (Lin7a), Complexin-2 (Cplx2) and Exocyst complex component 8 (Exoc8) genes in the offspring rat. Fisetin also prevented MeHg exposure induced downregulation of brain derived neurotrophic factor (BDNF), Glial-cell derived neurotrophic factor (GDNF) protein expressions and hampered reactive astrogliosis in the hippocampus of F1 generation rats. Hence, through this study, we conclude that Fisetin modulates the expression of regulatory genes and proteins involved in synaptic transmission and plasticity and extenuates MeHg neurotoxicity in the developing rat brain.
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Affiliation(s)
- Sherin Jacob
- Department of Medical Biochemistry, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, 600113, Tamil Nadu, India
| | - Thangarajan Sumathi
- Department of Medical Biochemistry, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, 600113, Tamil Nadu, India.
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23
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Santana LNDS, Bittencourt LO, Nascimento PC, Fernandes RM, Teixeira FB, Fernandes LMP, Freitas Silva MC, Nogueira LS, Amado LL, Crespo-Lopez ME, Maia CDSF, Lima RR. Low doses of methylmercury exposure during adulthood in rats display oxidative stress, neurodegeneration in the motor cortex and lead to impairment of motor skills. J Trace Elem Med Biol 2019; 51:19-27. [PMID: 30466930 DOI: 10.1016/j.jtemb.2018.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/21/2018] [Accepted: 09/10/2018] [Indexed: 12/20/2022]
Abstract
Despite the vast distribution among tissues, the central nervous system (CNS) represents the main target of methylmercury (MeHg) toxicity. However, few studies have evaluated the effects of MeHg exposure on the CNS at equivalent doses to human environmental exposure. In our study, we evaluated the motor cortex, an important area of motor control, in adult rats chronically exposed to MeHg in a concentration equivalent to those found in fish-eating populations exposed to mercury (Hg). The parameters evaluated were total Hg accumulation, oxidative stress, tissue damage, and behavioral assessment in functional actions that involved this cortical region. Our results show in exposed animals a significantly greater level of Hg in the motor cortex; increase of nitrite levels and lipid peroxidation, associated with decreased antioxidant capacity against peroxyl radicals; reduction of neuronal and astrocyte density; and poor coordination and motor learning impairment. Our data showed that chronic exposure at low doses to MeHg is capable of promoting damages to the motor cortex of adult animals, with changes in oxidative biochemistry misbalance, neurodegeneration, and motor function impairment.
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Affiliation(s)
- Luana Nazaré da Silva Santana
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Priscila Cunha Nascimento
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Rafael Monteiro Fernandes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Francisco Bruno Teixeira
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Luanna Melo Pereira Fernandes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Marcia Cristina Freitas Silva
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Lygia Sega Nogueira
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Lílian Lund Amado
- Laboratory of Ecotoxicology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Maria Elena Crespo-Lopez
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Cristiane do Socorro Ferraz Maia
- Laboratory of Pharmacology of Inflammation and Behavior, Institute of Health Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil.
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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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25
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Unoki T, Akiyama M, Kumagai Y, Gonçalves FM, Farina M, da Rocha JBT, Aschner M. Molecular Pathways Associated With Methylmercury-Induced Nrf2 Modulation. Front Genet 2018; 9:373. [PMID: 30271424 PMCID: PMC6146031 DOI: 10.3389/fgene.2018.00373] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 08/23/2018] [Indexed: 12/19/2022] Open
Abstract
Methylmercury (MeHg) is a potent neurotoxin that affects particularly the developing brain. Since MeHg is a potent electrophilic agent, a wide range of intracellular effects occur in response to its exposure. Yet, the molecular mechanisms associated with MeHg-induced cell toxicity have yet to be fully understood. Activation of cell defense mechanisms in response to metal exposure, including the up-regulation of Nrf2- (nuclear factor erythroid 2-related factor 2)-related genes has been previously shown. Nrf2 is a key regulator of cellular defenses against oxidative, electrophilic and environmental stress, regulating the expression of antioxidant proteins, phase-II xenobiotic detoxifying enzymes as well phase-III xenobiotic transporters. Analogous to other electrophiles, MeHg activates Nrf2 through modification of its repressor Keap1 (Kelch-like ECH-associated protein 1). However, recent findings have also revealed that Keap1-independent signal pathways might contribute to MeHg-induced Nrf2 activation and cytoprotective responses against MeHg exposure. These include, Akt phosphorylation (Akt/GSK-3β/Fyn-mediated Nrf2 activation pathway), activation of the PTEN/Akt/CREB pathway and MAPK-induced autophagy and p62 expression. In this review, we summarize the state-of-the-art knowledge regarding Nrf2 up-regulation in response to MeHg exposure, highlighting the modulation of signaling pathways related to Nrf2 activation. The study of these mechanisms is important in evaluating MeHg toxicity in humans, and can contribute to the identification of the molecular mechanisms associated with MeHg exposure.
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Affiliation(s)
- Takamitsu Unoki
- Department of Basic Medical Sciences, National Institute for Minamata Diseasexy3Minamata, Japan
| | - Masahiro Akiyama
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Yoshito Kumagai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Filipe Marques Gonçalves
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Marcelo Farina
- Department of Biochemistry, Federal University of Santa Catarina, Florianópolis, Brazil
| | | | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
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26
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Sex-Specific Response of Caenorhabditis elegans to Methylmercury Toxicity. Neurotox Res 2018; 35:208-216. [DOI: 10.1007/s12640-018-9949-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/10/2018] [Accepted: 08/15/2018] [Indexed: 10/28/2022]
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27
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Ruszkiewicz JA, Teixeira de Macedo G, Miranda-Vizuete A, Teixeira da Rocha JB, Bowman AB, Bornhorst J, Schwerdtle T, Aschner M. The cytoplasmic thioredoxin system in Caenorhabditis elegans affords protection from methylmercury in an age-specific manner. Neurotoxicology 2018; 68:189-202. [PMID: 30138651 DOI: 10.1016/j.neuro.2018.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/03/2018] [Accepted: 08/17/2018] [Indexed: 10/28/2022]
Abstract
Methylmercury (MeHg) is an environmental pollutant linked to many neurological defects, especially in developing individuals. The thioredoxin (TRX) system is a key redox regulator affected by MeHg toxicity, however the mechanisms and consequences of MeHg-induced dysfunction are not completely understood. This study evaluated the role of the TRX system in C. elegans susceptibility to MeHg during development. Worms lacking or overexpressing proteins from the TRX family were exposed to MeHg for 1 h at different developmental stage: L1, L4 and adult. Worms without cytoplasmic thioredoxin system exhibited age-specific susceptibility to MeHg when compared to wild-type (wt). This susceptibility corresponded partially to decreased total glutathione (GSH) levels and enhanced degeneration of dopaminergic neurons. In contrast, the overexpression of the cytoplasmic system TRX-1/TRXR-1 did not provide substantial protection against MeHg. Moreover, transgenic worms exhibited decreased protein expression for cytoplasmic thioredoxin reductase (TRXR-1). Both mitochondrial thioredoxin system TRX-2/TRXR-2, as well as other thioredoxin-like proteins: TRX-3, TRX-4, TRX-5 did not show significant role in C. elegans resistance to MeHg. Based on the current findings, the cytoplasmic thioredoxin system TRX-1/TRXR-1 emerges as an important age-sensitive protectant against MeHg toxicity in C. elegans.
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Affiliation(s)
- Joanna A Ruszkiewicz
- Department of Molecular Pharmacology, Albert Einstein College of Medicine Bronx, NY, United States.
| | - Gabriel Teixeira de Macedo
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Antonio Miranda-Vizuete
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - João B Teixeira da Rocha
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Aaron B Bowman
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Julia Bornhorst
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - Tanja Schwerdtle
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine Bronx, NY, United States
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28
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Antunes Dos Santos A, Ferrer B, Marques Gonçalves F, Tsatsakis AM, Renieri EA, Skalny AV, Farina M, Rocha JBT, Aschner M. Oxidative Stress in Methylmercury-Induced Cell Toxicity. TOXICS 2018; 6:toxics6030047. [PMID: 30096882 PMCID: PMC6161175 DOI: 10.3390/toxics6030047] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/03/2018] [Accepted: 08/07/2018] [Indexed: 02/06/2023]
Abstract
Methylmercury (MeHg) is a hazardous environmental pollutant, which elicits significant toxicity in humans. The accumulation of MeHg through the daily consumption of large predatory fish poses potential health risks, and the central nervous system (CNS) is the primary target of toxicity. Despite well-described neurobehavioral effects (i.e., motor impairment), the mechanisms of MeHg-induced toxicity are not completely understood. However, several lines of evidence point out the oxidative stress as an important molecular mechanism in MeHg-induced intoxication. Indeed, MeHg is a soft electrophile that preferentially interacts with nucleophilic groups (mainly thiols and selenols) from proteins and low-molecular-weight molecules. Such interaction contributes to the occurrence of oxidative stress, which can produce damage by several interacting mechanisms, impairing the function of various molecules (i.e., proteins, lipids, and nucleic acids), potentially resulting in modulation of different cellular signal transduction pathways. This review summarizes the general aspects regarding the interaction between MeHg with regulators of the antioxidant response system that are rich in thiol and selenol groups such as glutathione (GSH), and the selenoenzymes thioredoxin reductase (TrxR) and glutathione peroxidase (Gpx). A particular attention is directed towards the role of the PI3K/Akt signaling pathway and the nuclear transcription factor NF-E2-related factor 2 (Nrf2) in MeHg-induced redox imbalance.
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Affiliation(s)
| | - Beatriz Ferrer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Filipe Marques Gonçalves
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Aristides M Tsatsakis
- Laboratory of Toxicology, Medical School, University of Crete, 71003 Heraklion, Greece.
| | - Elisavet A Renieri
- Laboratory of Toxicology, Medical School, University of Crete, 71003 Heraklion, Greece.
| | - Anatoly V Skalny
- Department of Medical Elementology, Peoples' Friendship University of Russia (RUDN University), Moscow 150000, Russia.
- Laboratory of Biotechnology and Applied Bioelementology, Yaroslavl State University, Yaroslavl 150014, Russia.
- All-Russian Research Institute of Medicinal and Aromatic Plants (VILAR), Moscow 150000, Russia.
| | - Marcelo Farina
- Department of Biochemistry, Federal University of Santa Catarina, Florianopolis 88040-900, Santa Catarina, Brazil.
| | - João B T Rocha
- Department of Biochemistry, Federal University of Santa Maria, Santa Maria 97105-900, Rio Grande do Sul, Brazil.
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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29
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Leão MB, da Rosa PCC, Wagner C, Lugokenski TH, Dalla Corte CL. Methylmercury and diphenyl diselenide interactions in Drosophila melanogaster: effects on development, behavior, and Hg levels. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:21568-21576. [PMID: 29785592 DOI: 10.1007/s11356-018-2293-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 05/09/2018] [Indexed: 06/08/2023]
Abstract
Methylmercury (MeHg) is a highly toxic environmental pollutant which binds with a high affinity to selenol groups. In view of this, seleno-compounds have been investigated as MeHg antidotes. In the present study, we evaluated the effects of the co-exposure to MeHg and the seleno-compound diphenyl diselenide (PhSe)2 on Drosophila melanogaster. We measured the survival rate, developmental survival, locomotor ability, reactive oxygen species (ROS) production, and Hg levels in D. melanogaster exposed to MeHg and/or (PhSe)2 in the food. Exposure to MeHg caused a reduction in the survival rate, developmental survival, and locomotion in D. melanogaster. In addition, MeHg increased the ROS production and mercury levels in flies. The co-exposure to MeHg and (PhSe)2 did not prevent the toxic effects of MeHg in D. melanogaster. On the contrary, the co-exposure enhanced the toxic effects on the locomotor ability and developmental survival. This effect may be explained by the fact that the co-exposure increased the Hg levels in body when compared to flies exposed only to MeHg, suggesting that MeHg and (PhSe)2 interaction may increase Hg body burden in D. melanogaster which could contribute for the increased toxicity observed in the co-exposure.
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Affiliation(s)
- Mayara B Leão
- Universidade Federal do Pampa, Campus Caçapava do Sul, Caçapava do Sul, RS, 96570-000, Brazil
| | - Paulo C C da Rosa
- Universidade Federal do Pampa, Campus Caçapava do Sul, Caçapava do Sul, RS, 96570-000, Brazil
| | - Caroline Wagner
- Universidade Federal do Pampa, Campus Caçapava do Sul, Caçapava do Sul, RS, 96570-000, Brazil
| | - Thiago H Lugokenski
- Universidade Federal do Pampa, Campus Caçapava do Sul, Caçapava do Sul, RS, 96570-000, Brazil
| | - Cristiane L Dalla Corte
- Universidade Federal do Pampa, Campus Caçapava do Sul, Caçapava do Sul, RS, 96570-000, Brazil.
- Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Camobi, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil.
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30
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Karri V, Ramos D, Martinez JB, Odena A, Oliveira E, Coort SL, Evelo CT, Mariman ECM, Schuhmacher M, Kumar V. Differential protein expression of hippocampal cells associated with heavy metals (Pb, As, and MeHg) neurotoxicity: Deepening into the molecular mechanism of neurodegenerative diseases. J Proteomics 2018; 187:106-125. [PMID: 30017948 DOI: 10.1016/j.jprot.2018.06.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/26/2018] [Accepted: 06/26/2018] [Indexed: 12/29/2022]
Abstract
Chronic exposure to heavy metals such as Pb, As, and MeHg can be associated with an increased risk of developing neurodegenerative diseases. Our in vitro bioassays results showed the potency of heavy metals in the order of Pb < As < MeHg on hippocampal cells. The main objective of this study was combining in vitro label free proteomics and systems biology approach for elucidating patterns of biological response, discovering underlying mechanisms of Pb, As, and MeHg toxicity in hippocampal cells. The omics data was refined by using different filters and normalization and multilevel analysis tools were employed to explore the data visualization. The functional and pathway visualization was performed by using Gene ontology and PathVisio tools. Using these all integrated approaches, we identified significant proteins across treatments within the mitochondrial dysfunction, oxidative stress, ubiquitin proteome dysfunction, and mRNA splicing related to neurodegenerative diseases. The systems biology analysis revealed significant alterations in proteins implicated in Parkinson's disease (PD) and Alzheimer's disease (AD). The current proteomics analysis of three metals support the insight into the proteins involved in neurodegeneration and the altered proteins can be useful for metal-specific biomarkers of exposure and its adverse effects. SIGNIFICANCE The proteomics techniques have been claimed to be more sensitive than the conventional toxicological assays, facilitating the measurement of responses to heavy metals (Pb, As, and MeHg) exposure before obvious harm has occurred demonstrating their predictive value. Also, proteomics allows for the comparison of responses between Pb, As, and MeHg metals, permitting the evaluation of potency differences hippocampal cells of the brain. Hereby, the molecular information provided by pathway and gene functional analysis can be used to develop a more thorough understanding of each metal mechanism at the protein level for different neurological adverse outcomes (e.g. Parkinson's disease, Alzheimer's diseases). Efforts are put into developing proteomics based toxicity testing methods using in vitro models for improving human risk assessment. Some of the key proteins identified can also potentially be used as biomarkers in epidemiologic studies. These heavy metal response patterns shed new light on the mechanisms of mRNA splicing, ubiquitin pathway role in neurodegeneration, and can be useful for the development of molecular biomarkers of heavy metals exposure.
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Affiliation(s)
- Venkatanaidu Karri
- Environmental Engineering Laboratory, Departament d'Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - David Ramos
- Plataforma de Proteòmica, Parc Científic de Barcelona, C/Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Julia Bauzá Martinez
- Plataforma de Proteòmica, Parc Científic de Barcelona, C/Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Antonia Odena
- Plataforma de Proteòmica, Parc Científic de Barcelona, C/Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Eliandre Oliveira
- Unidad de Toxicologia, Parc Científic de Barcelona, C/Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Susan L Coort
- Department of Bioinformatics, BiGCaT, NUTRIM, Maastricht University, 6229, ER, Maastricht, the Netherlands
| | - Chris T Evelo
- Department of Bioinformatics, BiGCaT, NUTRIM, Maastricht University, 6229, ER, Maastricht, the Netherlands
| | - Edwin C M Mariman
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Marta Schuhmacher
- Environmental Engineering Laboratory, Departament d'Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - Vikas Kumar
- Environmental Engineering Laboratory, Departament d'Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain; IISPV, Hospital Universitari Sant Joan de Reus, Universitat Rovira I Virgili, Reus, Spain.
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31
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Puga S, Cardoso V, Pinto-Ribeiro F, Pacheco M, Almeida A, Pereira P. Brain morphometric profiles and their seasonal modulation in fish (Liza aurata) inhabiting a mercury contaminated estuary. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:318-328. [PMID: 29499575 DOI: 10.1016/j.envpol.2018.02.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/09/2018] [Accepted: 02/16/2018] [Indexed: 06/08/2023]
Abstract
Mercury (Hg) is a potent neurotoxicant known to induce important adverse effects on fish, but a deeper understanding is lacking regarding how environmental exposure affects the brain morphology and neural plasticity of specific brain regions in wild specimens. In this work, it was evaluated the relative volume and cell density of the lateral pallium, hypothalamus, optic tectum and molecular layer of the cerebellum on wild Liza aurata captured in Hg-contaminated (LAR) and non-contaminated (SJ) sites of a coastal system (Ria de Aveiro, Portugal). Given the season-related variations in the environment that fish are naturally exposed, this assessment was performed in the winter and summer. Hg triggered a deficit in cell density of hypothalamus during the winter that could lead to hormonal dysfunctions, while in the summer Hg promoted larger volumes of the optic tectum and cerebellum, indicating the warm period as the most critical for the manifestation of putative changes in visual acuity and motor-dependent tasks. Moreover, in fish from the SJ site, the lateral pallium relative volume and the cell density of the hypothalamus and optic tectum were higher in the winter than in summer. Thus, season-related stimuli strongly influence the size and/or cell density of specific brain regions in the non-contaminated area, pointing out the ability of fish to adapt to environmental and physiological demands. Conversely, fish from the Hg-contaminated site showed a distinct seasonal profile of brain morphology, presenting a larger optic tectum in the summer, as well as a larger molecular layer of the cerebellum with higher cell density. Moreover, Hg exposure impaired the winter-summer variation of the lateral pallium relative size (as observed at SJ). Altogether, seasonal variations in fish neural morphology and physiology should be considered when performing ecotoxicological studies in order to better discriminate the Hg neurotoxicity.
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Affiliation(s)
- Sónia Puga
- Life and Health Sciences Research Institute (ICVS), School of Medicine (EM), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Vera Cardoso
- Life and Health Sciences Research Institute (ICVS), School of Medicine (EM), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Filipa Pinto-Ribeiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine (EM), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Mário Pacheco
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Armando Almeida
- Life and Health Sciences Research Institute (ICVS), School of Medicine (EM), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Patrícia Pereira
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
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Wahlberg K, Love TM, Pineda D, Engström K, Watson GE, Thurston SW, Yeates AJ, Mulhern MS, McSorley EM, Strain JJ, Smith TH, Davidson PW, Shamlaye CF, Myers GJ, Rand MD, van Wijngaarden E, Broberg K. Maternal polymorphisms in glutathione-related genes are associated with maternal mercury concentrations and early child neurodevelopment in a population with a fish-rich diet. ENVIRONMENT INTERNATIONAL 2018; 115:142-149. [PMID: 29573653 PMCID: PMC5970067 DOI: 10.1016/j.envint.2018.03.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/11/2018] [Accepted: 03/11/2018] [Indexed: 05/05/2023]
Abstract
INTRODUCTION Glutathione (GSH) pathways play a key role the metabolism and elimination of the neurotoxicant methylmercury (MeHg). We hypothesized that maternal genetic variation linked to GSH pathways could influence MeHg concentrations in pregnant mothers and children and thereby also affect early life development. METHODS The GCLM (rs41303970, C/T), GCLC (rs761142, T/G) and GSTP1 (rs1695, A/G) polymorphisms were genotyped in 1449 mothers in a prospective study of the Seychellois population with a diet rich in fish. Genotypes were analyzed in association with maternal hair and blood Hg, fetal blood Hg (cord blood Hg), as well as children's mental (MDI) and motor development (PDI; MDI and PDI assessed by Bayley Scales of Infant Development at 20 months). We also examined whether genotypes modified the association between Hg exposure and developmental outcomes. RESULTS GCLC rs761142 TT homozygotes showed statistically higher mean maternal hair Hg (4.12 ppm) than G carriers (AG 3.73 and GG 3.52 ppm) (p = 0.037). For the combination of GCLC rs761142 and GCLM rs41303970, double homozygotes TT + CC showed higher hair Hg (4.40 ppm) than G + T carriers (3.44 ppm; p = 0.018). No associations were observed between GSTP1 rs1695 and maternal hair Hg or between any genotypes and maternal blood Hg or cord blood Hg. The maternal GSTP1 rs1695 rare allele (G) was associated with a lower MDI among children (β = -1.48, p = 0.048). We also observed some interactions: increasing Hg in maternal and cord blood was associated with lower PDI among GCLC rs761142 TT carriers; and increasing Hg in hair was associated with lower MDI among GSTP1 rs1695 GG carriers. CONCLUSIONS Maternal genetic variation in genes involved in GSH synthesis is statistically associated with Hg concentrations in maternal hair, but not in maternal or fetal blood. We observed interactions that suggest maternal GSH genetics may modify associations between MeHg exposure and neurodevelopmental outcomes.
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Affiliation(s)
- Karin Wahlberg
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, 22185 Lund, Sweden
| | - Tanzy M Love
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Daniela Pineda
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, 22185 Lund, Sweden
| | - Karin Engström
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, 22185 Lund, Sweden
| | - Gene E Watson
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Sally W Thurston
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Alison J Yeates
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Cromore Road, Coleraine BT52 1SA, Co. Londonderry, UK
| | - Maria S Mulhern
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Cromore Road, Coleraine BT52 1SA, Co. Londonderry, UK
| | - Emeir M McSorley
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Cromore Road, Coleraine BT52 1SA, Co. Londonderry, UK
| | - J J Strain
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Cromore Road, Coleraine BT52 1SA, Co. Londonderry, UK
| | - Tristram H Smith
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, 22185 Lund, Sweden
| | - Philip W Davidson
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | | | - G J Myers
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Matthew D Rand
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Edwin van Wijngaarden
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Karin Broberg
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, 22185 Lund, Sweden; Institute of Environmental Medicine, Metals and Health, Box 210, 171 77 Stockholm, Sweden.
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Oliveira CS, Nogara PA, Ardisson-Araújo DMP, Aschner M, Rocha JBT, Dórea JG. Neurodevelopmental Effects of Mercury. ADVANCES IN NEUROTOXICOLOGY 2018; 2:27-86. [PMID: 32346667 PMCID: PMC7188190 DOI: 10.1016/bs.ant.2018.03.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The toxicology of mercury (Hg) is of concern since this metal is ubiquitously distributed in the environment, and living organisms are routinely exposed to Hg at low to high levels. The toxic effects of Hg are well studied and it is known that they may differ depending on the Hg chemical species. In this chapter, we emphasize the neurotoxic effects of Hg during brain development. The immature brain is more susceptible to Hg exposure, since all the Hg chemical forms, not only the organic ones, can harm it. The possible consequences of Hg exposure during the early stages of development, the additive effects with other co-occurring neurotoxicants, and the known mechanisms of action and targets will be addressed in this chapter.
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Affiliation(s)
- Cláudia S Oliveira
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Pablo A Nogara
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Daniel M P Ardisson-Araújo
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Laboratório de Virologia de Insetos, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY, USA
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - José G Dórea
- Professor Emeritus, Faculdade de Ciências da Saúde, Universidade de Brasília, Brasília, DF, Brazil
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Raciti M, Ceccatelli S. Epigenetic mechanisms in developmental neurotoxicity. Neurotoxicol Teratol 2018; 66:94-101. [DOI: 10.1016/j.ntt.2017.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 12/28/2022]
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Spulber S, Raciti M, Dulko-Smith B, Lupu D, Rüegg J, Nam K, Ceccatelli S. Methylmercury interferes with glucocorticoid receptor: Potential role in the mediation of developmental neurotoxicity. Toxicol Appl Pharmacol 2018; 354:94-100. [PMID: 29499248 DOI: 10.1016/j.taap.2018.02.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 02/25/2018] [Accepted: 02/26/2018] [Indexed: 12/14/2022]
Abstract
Methylmercury (MeHg) is a widespread environmental contaminant with established developmental neurotoxic effects. Computational models have identified glucocorticoid receptor (GR) signaling to be a key mediator behind the birth defects induced by Hg, but the mechanisms were not elucidated. Using molecular dynamics simulations, we found that MeHg can bind to the GR protein at Cys736 (located close to the ligand binding site) and distort the conformation of the ligand binging site. To assess the functional consequences of MeHg interaction with GR, we used a human cell line expressing a luciferase reporter system (HeLa AZ-GR). We found that 100 nM MeHg does not have any significant effect on GR activity alone, but the transactivation of gene expression by GR upon Dex (a synthetic GR agonist) administration was reduced in cells pre-treated with MeHg. Similar effects were found in transgenic zebrafish larvae expressing a GR reporter system (SR4G). Next we asked whether the effects of developmental exposure to MeHg are mediated by the effects on GR. Using a mutant zebrafish line carrying a loss-of-function mutation in the GR (grS357) we could show that the effects of developmental exposure to 2.5 nM MeHg are mitigated in absence of functional GR signaling. Taken together, our data indicate that inhibition of GR signaling may have a role in the developmental neurotoxic effects of MeHg.
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Affiliation(s)
- S Spulber
- Karolinska Institutet, Department of Neuroscience, Stockholm, Sweden.
| | - M Raciti
- Karolinska Institutet, Department of Neuroscience, Stockholm, Sweden
| | - B Dulko-Smith
- Umeå University, Faculty of Science and Technology, Department of Chemistry, Umeå, Sweden; University of Texas at Arlington, Department of Chemistry and Biochemistry, Arlington, TX, USA
| | - D Lupu
- Swetox, Karolinska Institutet, Unit of Toxicology Science, Södertälje, Sweden; "Iuliu Hatieganu" University of Medicine and Pharmacy, Department of Toxicology, Cluj-Napoca, Romania
| | - J Rüegg
- Swetox, Karolinska Institutet, Unit of Toxicology Science, Södertälje, Sweden; Karolinska Institutet, Department of Clinical Neuroscience, Stockholm, Sweden
| | - K Nam
- Umeå University, Faculty of Science and Technology, Department of Chemistry, Umeå, Sweden; University of Texas at Arlington, Department of Chemistry and Biochemistry, Arlington, TX, USA
| | - S Ceccatelli
- Karolinska Institutet, Department of Neuroscience, Stockholm, Sweden
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Karri V, Kumar V, Ramos D, Oliveira E, Schuhmacher M. An in vitro cytotoxic approach to assess the toxicity of heavy metals and their binary mixtures on hippocampal HT-22 cell line. Toxicol Lett 2018; 282:25-36. [DOI: 10.1016/j.toxlet.2017.10.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/24/2017] [Accepted: 10/02/2017] [Indexed: 12/23/2022]
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Dao CV, Shiraishi M, Miyamoto A. The MARCKS protein amount is differently regulated by calpain during toxic effects of methylmercury between SH-SY5Y and EA.hy926 cells. J Vet Med Sci 2017; 79:1931-1938. [PMID: 29046508 PMCID: PMC5745167 DOI: 10.1292/jvms.17-0473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Methylmercury (MeHg) is an environmental pollutant that shows severe toxicity to humans and animals. However, the molecular mechanisms mediating MeHg toxicity are not completely understood. We have previously reported that the MARCKS protein is involved in the MeHg toxicity to SH-SY5Y neuroblastoma and EA.hy926 vascular endothelial cell lines. In addition, calpain, a Ca2+-dependent protease, is suggested to be associated with the MeHg toxicity. Because MARCKS is known as a substrate of calpain, we studied the relation between calpain activation and cleavage of MARCKS and its role in MeHg toxicity. In SH-SY5Y cells, MeHg decreased cell viability along with increased calcium mobilization, calpain activation and a decrease in MARCKS amounts. However, pretreatment with calpain inhibitors attenuated the decrease in cell viability and MARCKS amount induced only by 1 µM but not by 3 µM MeHg. In cells with a MARCKS knockdown, calpain inhibitors failed to attenuate the decrease in cell viability caused by MeHg. In EA.hy926 cells, although MeHg caused calcium mobilization and a decrease in MARCKS levels, calpain activation was not observed. These results indicate that the participation of calpain in the regulation of MARCKS amounts is dependent on the cell type and concentration of MeHg. In SH-SY5Y cells, calpain-mediated proteolysis of MARCKS is involved in cytotoxicity induced by a low concentration of MeHg.
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Affiliation(s)
- Cuong Van Dao
- Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.,Department of Veterinary Pharmacology, Faculty of Animal Husbandry and Veterinary Medicine, Thai Nguyen University of Agriculture and Forestry, Group 10, Quyet Thang Commune, Thai Nguyen City, Thai Nguyen, Vietnam
| | - Mitsuya Shiraishi
- Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Atsushi Miyamoto
- Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
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Al-Saleh I, Al-Rouqi R, Elkhatib R, Abduljabbar M, Al-Rajudi T. Risk assessment of environmental exposure to heavy metals in mothers and their respective infants. Int J Hyg Environ Health 2017; 220:1252-1278. [PMID: 28869188 DOI: 10.1016/j.ijheh.2017.07.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 07/26/2017] [Accepted: 07/31/2017] [Indexed: 12/17/2022]
Abstract
Exposure to heavy metals can cause renal injury, which has been well documented in occupational exposure. Studies of low exposure in the general population, however, are still scarce, particularly for vulnerable populations such as mothers and young children. This study evaluated exposure to heavy metals, and biomarkers of renal function and oxidative stress in 944 lactating mothers and their infants and investigated the role of the interaction between heavy metals and oxidative stress in altering renal function. Mother and infant urine samples were analyzed to measure mercury (Hg), cadmium (Cd), and lead (Pb) concentrations for determining body-burden exposure; N-acetyl-β-d-glucosaminidase (NAG), α1-microglobulin (α1-MG), albumin (ALB), and creatinine (Cr) concentrations for determining early renal injury; and 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) concentrations for determining oxidative stress. The median concentrclearlyations in mothers presented as μg/g Cr (infants as μg/l) for Hg, Cd, and Pb were 0.695 (0.716), 0.322 (0.343), and 3.97 (5.306) respectively. The mothers and their infants had clearly been exposed to heavy metals and had levels higher than the reference values reported for the general populations of USA, Germany, and Canada. Multiple regression analyses clearly demonstrated associations between urinary heavy metals in quartiles and several renal and oxidative biomarkers in mothers and to a lesser extent their infants. ß coefficients for urinary excretions of MDA, 8-OHdG, ALB, α1-MG, NAG, and Cr in mothers were high in the highest quartile of Hg (1.183-51.29μg/g Cr or 1.732-106.95μg/l), Cd (0.565-765.776μg/g Cr or 0.785-1347.0μg/l), and Pb (6.606-83.937μg/g Cr or 9.459-80.826μg/l), except Pb was not associated with ALB. Infants in the highest Pb quartile (9.293-263.098μg/l) had the highest ß coefficients of urinary excretion of MDA, 8-OHdG, ALB, NAG, and Cr. Significant increasing trend in biomarkers across the quartiles of the three metals was seen in both mothers and infants (ptrend <0.001). A receiver operating characteristic analysis supported the predictive abilities of the four renal biomarkers in discriminating between low versus high metal quartiles. The interaction between heavy metals and oxidative stress contributed to the high excretions of renal biomarkers, but the mechanism remains unclear. These findings add to the limited evidence that low exposure to heavy metals in the general population is associated with alterations in renal function that could eventually progress to renal damage if exposure continues and that children are more susceptible due to the immaturity of their body organs.
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Affiliation(s)
- Iman Al-Saleh
- Environmental Health Program, Research Centre, King Faisal Specialist Hospital and Research Centre, P.O. Box: 3354, Riyadh 11211, Saudi Arabia.
| | - Reem Al-Rouqi
- Environmental Health Program, Research Centre, King Faisal Specialist Hospital and Research Centre, P.O. Box: 3354, Riyadh 11211, Saudi Arabia
| | - Rola Elkhatib
- Environmental Health Program, Research Centre, King Faisal Specialist Hospital and Research Centre, P.O. Box: 3354, Riyadh 11211, Saudi Arabia
| | - Mai Abduljabbar
- Environmental Health Program, Research Centre, King Faisal Specialist Hospital and Research Centre, P.O. Box: 3354, Riyadh 11211, Saudi Arabia
| | - Tahreer Al-Rajudi
- Environmental Health Program, Research Centre, King Faisal Specialist Hospital and Research Centre, P.O. Box: 3354, Riyadh 11211, Saudi Arabia
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Kalia V, Perera F, Tang D. Environmental Pollutants and Neurodevelopment: Review of Benefits From Closure of a Coal-Burning Power Plant in Tongliang, China. Glob Pediatr Health 2017; 4:2333794X17721609. [PMID: 28812058 PMCID: PMC5542072 DOI: 10.1177/2333794x17721609] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 06/13/2017] [Accepted: 06/21/2017] [Indexed: 12/02/2022] Open
Abstract
Background. Understanding preventable causes of neurodevelopmental disorders is a public health priority. Polycyclic aromatic hydrocarbons (PAH) from combustion of fossil fuel, lead, and mercury are among known neurodevelopmental toxicants. Method. For the first time, we comprehensively review the findings from a study by the Columbia Center for Children's Environmental Health and Chinese partners that followed 2 groups of mother-child pairs, one from 2002 and another from 2005, in Tongliang County, China. Pregnant mothers in the 2 cohorts experienced different exposure to PAH because a local coal-burning power plant was shut down in 2004. Investigators assessed change in prenatal PAH exposure, measured using a biomarker (benzo[a]pyrene [BaP]-DNA adducts in cord blood). Developmental quotients were measured using the Gesell Developmental Scales at age 2 and IQ was assessed using the Wechsler Intelligence Scale for Children at age 5. Biologic markers of preclinical response were measured in cord blood: methylation status of long interspersed nuclear elements (LINE1), an indicator of genomic stability, and brain-derived neurotrophic factor (BDNF), a neuronal growth promoter. Analyses accounted for co-exposure to lead and mercury. Results. BaP-DNA adducts were significantly inversely associated with Gesell Developmental Scales scores in the first cohort but not in the second cohort; and levels of BDNF and LINE1 methylation were higher in the second cohort. Conclusion. In this study, reduced exposure to PAH was associated with beneficial effects on neurodevelopment as well as molecular changes related to improved brain development and health. These benefits should encourage further efforts to limit exposure to these toxic pollutants.
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Affiliation(s)
- Vrinda Kalia
- Department of Environmental Health Sciences, Columbia Center for Children’s Environemental Health, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Frederica Perera
- Department of Environmental Health Sciences, Columbia Center for Children’s Environemental Health, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Deliang Tang
- Department of Environmental Health Sciences, Columbia Center for Children’s Environemental Health, Mailman School of Public Health, Columbia University, New York, NY, USA
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Edoff K, Raciti M, Moors M, Sundström E, Ceccatelli S. Gestational Age and Sex Influence the Susceptibility of Human Neural Progenitor Cells to Low Levels of MeHg. Neurotox Res 2017; 32:683-693. [PMID: 28756503 PMCID: PMC5602033 DOI: 10.1007/s12640-017-9786-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 07/09/2017] [Accepted: 07/12/2017] [Indexed: 01/13/2023]
Abstract
The developing nervous system is highly susceptible to methylmercury (MeHg), a widespread environmental neurotoxic contaminant. A wide range of morphological and functional outcomes have been described; however, there are still open questions regarding the mechanisms behind the developmental neurotoxic effects induced by low-level exposure. In the present study, we have examined the effects of nanomolar concentrations of MeHg on primary fetal human progenitor cells (hNPCs) with special focus on the role played by developmental stage and sex on the neurotoxic outcome. We found that neurospheres derived from earlier gestational time points exhibit higher susceptibility to MeHg, as they undergo apoptosis at a much lower dose (25 nM) as compared to neurospheres established from older fetuses (100 nM). At subapoptotic concentrations (10 nM), MeHg inhibited neuronal differentiation and maturation of hNPCs, as shown by a reduced number of Tuj1-positive cells and a visible reduction in neurite extension and cell migration, associated with a misregulation of Notch1 and BDNF signaling pathways. Interestingly, cells derived from male fetuses showed more severe alterations of neuronal morphology as compared to cells from females, indicating that the MeHg-induced impairment of neurite extension and cell migration is sex-dependent. Accordingly, the expression of the CDKL5 gene, a major factor regulating neurite outgrowth, was significantly more downregulated in male-derived cells. Altogether, gestational age and sex appear to be critical factors influencing in vitro hNPC sensitivity to low levels of MeHg.
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Affiliation(s)
- Karin Edoff
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77, Stockholm, Sweden
| | - Marilena Raciti
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77, Stockholm, Sweden.
| | - Michaela Moors
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77, Stockholm, Sweden
| | - Erik Sundström
- Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Geriatrik-lab plan 5, SE-141 52, Huddinge, Sweden
| | - Sandra Ceccatelli
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77, Stockholm, Sweden
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Clinical effects of chemical exposures on mitochondrial function. Toxicology 2017; 391:90-99. [PMID: 28757096 DOI: 10.1016/j.tox.2017.07.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/07/2017] [Accepted: 07/17/2017] [Indexed: 12/16/2022]
Abstract
Mitochondria are critical for the provision of ATP for cellular energy requirements. Tissue and organ functions are dependent on adequate ATP production, especially when energy demand is high. Mitochondria also play a role in a vast array of important biochemical pathways including apoptosis, generation and detoxification of reactive oxygen species, intracellular calcium regulation, steroid hormone and heme synthesis, and lipid metabolism. The complexity of mitochondrial structure and function facilitates its diverse roles but also enhances its vulnerability. Primary disorders of mitochondrial bioenergetics, or Primary Mitochondrial Diseases (PMD) are due to inherited genetic defects in the nuclear or mitochondrial genomes that result in defective oxidative phosphorylation capacity and cellular energy production. Secondary mitochondrial dysfunction is observed in a wide range of diseases such as Alzheimer's and Parkinson's disease. Several lines of evidence suggest that environmental exposures cause substantial mitochondrial dysfunction. Whereby literature from experimental and human studies on exposures associated with Alzheimer's and Parkinson's diseases exist, the significance of exposures as potential triggers in Primary Mitochondrial Disease (PMD) is an emerging clinical question that has not been systematically studied.
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Heyer DB, Meredith RM. Environmental toxicology: Sensitive periods of development and neurodevelopmental disorders. Neurotoxicology 2017; 58:23-41. [DOI: 10.1016/j.neuro.2016.10.017] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/25/2016] [Accepted: 10/31/2016] [Indexed: 11/16/2022]
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Rudgalvyte M, Peltonen J, Lakso M, Wong G. Chronic MeHg exposure modifies the histone H3K4me3 epigenetic landscape in Caenorhabditis elegans. Comp Biochem Physiol C Toxicol Pharmacol 2017; 191:109-116. [PMID: 27717699 DOI: 10.1016/j.cbpc.2016.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 09/29/2016] [Accepted: 10/02/2016] [Indexed: 01/05/2023]
Abstract
Methylmercury (MeHg) is a persistent environmental pollutant that occurs in the food chain, at occupational sites, and via medical procedures. Exposure in humans and animal models results in renal, neuro, and reproductive toxicities. In this study, we demonstrate that chronic exposure to MeHg (10μM) causes epigenetic landscape modifications of histone H3K4 trimethylation (H3K4me3) marks in Caenorhabditis elegans using chromatin immuno-precipitation sequencing (ChIP-seq). The modifications correspond to the locations of 1467 genes with enhanced and 508 genes with reduced signals. Among enhanced genes are those encoding glutathione-S-transferases, lipocalin-related protein and a cuticular collagen. ChIP-seq enhancement of these genes was confirmed with increased mRNA expression levels revealed by qRT-PCR. Furthermore, we observed enhancement of H3K4me3 marks in these genes in animals exposed to MeHg in utero and assayed at L4 stage. In utero exposure enhanced marks without alterations in mRNA expression except for the lpr-5 gene. Finally, knockdown of lipocalin-related protein gene lpr-5, which is involved in intercellular signaling, and cuticular collagen gene dpy-7, structural component of the cuticle, by RNA interference (RNAi) resulted in increased lethality of animals after MeHg exposure. Our results provide new data on the epigenetic landscape changes elicited by MeHg exposure, as well as describe a unique model for studying in utero effects of heavy metals. Together, these findings may help to understand the toxicological effects of MeHg at the molecular level.
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Affiliation(s)
- Martina Rudgalvyte
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio, Finland; Faculty of Health Sciences, University of Macau, Macau, S.A.R., China
| | - Juhani Peltonen
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio, Finland
| | - Merja Lakso
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio, Finland
| | - Garry Wong
- Faculty of Health Sciences, University of Macau, Macau, S.A.R., China.
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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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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: 274] [Impact Index Per Article: 34.3] [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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Al-Saleh I, Elkhatib R, Al-Rouqi R, Abduljabbar M, Eltabache C, Al-Rajudi T, Nester M. Alterations in biochemical markers due to mercury (Hg) exposure and its influence on infant's neurodevelopment. Int J Hyg Environ Health 2016; 219:898-914. [PMID: 27453562 DOI: 10.1016/j.ijheh.2016.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/26/2016] [Accepted: 07/01/2016] [Indexed: 01/04/2023]
Abstract
This study examined the role of oxidative stress due to mercury (Hg) exposure on infant's neurodevelopmental performance. A total of 944 healthy Saudi mothers and their respective infants (aged 3-12 months) were recruited from 57 Primary Health Care Centers in Riyadh City. Total mercury (Hg) was measured in mothers and infants urine and hair samples, as well as mother's blood and breast milk. Methylmercury (MeHg) was determined in the mothers and infants' hair and mother's blood. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA), and porphyrins were used to assess oxidative stress. The infant's neurodevelopment was evaluated using Denver Developmental Screening Test II (DDST-II) and Parents' Evaluation of Developmental Status. The median total Hg levels in mother's urine, infant's urine, mother's hair, infant's hair, and mother's blood and breast milk were 0.995μg/l, 0.716μg/l, 0.118μg/g dw, 0.101μg/g dw, 0.635μg/l, and 0.884μg/l respectively. The median MeHg levels in mother's hair, infant's hair, and mother's blood were 0.132μg/g dw, 0.091μg/g dw, and 2.341μg/l respectively. A significant interrelationship between mothers and infants Hg measures in various matrices was noted. This suggests that mother's exposure to different forms of Hg (total and/or MeHg) from various sources contributed significantly to the metal body burden of their respective infants. Even though Hg exposure was low, it induced high oxidative stress in mothers and infants. The influence of multiplicative interaction terms between Hg measures and oxidative stress biomarkers was tested using multiple regression analysis. Significant interactions between the urinary Hg levels in mothers and infants and oxidative stress biomarkers (8-OHdG and MDA) were noted. The MeHg levels in mother-infant hair revealed similar interaction patterns. The p-values for both were below 0.001. These observations suggest that the exposure of our infants to Hg via mothers either during pregnancy and/or neonatal life, promoted oxidative stress that might have played a role in infant neurodevelopmental delays that we reported previously. The results confirmed that the interaction between infant's MeHg in hair and 8-OHdG and MDA levels was significantly associated with a delay in DDST-II performance (ß=-0.188, p=0.028). This finding provides an insight into the potential consequences of Hg-induced oxidative stress to infant's cognitive neurodevelopment for the first time. This observation still needs future studies to be validated. Given the low MeHg levels in our population, these findings are of particular importance.
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Affiliation(s)
- Iman Al-Saleh
- Environmental Health Program, King Faisal Specialist Hospital and Research Centre, PO Box: 3354, Riyadh 11211, Saudi Arabia.
| | - Rola Elkhatib
- Environmental Health Program, King Faisal Specialist Hospital and Research Centre, PO Box: 3354, Riyadh 11211, Saudi Arabia
| | - Reem Al-Rouqi
- Environmental Health Program, King Faisal Specialist Hospital and Research Centre, PO Box: 3354, Riyadh 11211, Saudi Arabia
| | - Mai Abduljabbar
- Environmental Health Program, King Faisal Specialist Hospital and Research Centre, PO Box: 3354, Riyadh 11211, Saudi Arabia
| | - Chafica Eltabache
- Environmental Health Program, King Faisal Specialist Hospital and Research Centre, PO Box: 3354, Riyadh 11211, Saudi Arabia
| | - Tahreer Al-Rajudi
- Environmental Health Program, King Faisal Specialist Hospital and Research Centre, PO Box: 3354, Riyadh 11211, Saudi Arabia
| | - Michael Nester
- Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, PO Box: 3354, Riyadh 11211, Saudi Arabia
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Tong ZB, Hogberg H, Kuo D, Sakamuru S, Xia M, Smirnova L, Hartung T, Gerhold D. Characterization of three human cell line models for high-throughput neuronal cytotoxicity screening. J Appl Toxicol 2016; 37:167-180. [PMID: 27143523 DOI: 10.1002/jat.3334] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 11/10/2022]
Abstract
More than 75 000 man-made chemicals contaminate the environment; many of these have not been tested for toxicities. These chemicals demand quantitative high-throughput screening assays to assess them for causative roles in neurotoxicities, including Parkinson's disease and other neurodegenerative disorders. To facilitate high throughput screening for cytotoxicity to neurons, three human neuronal cellular models were compared: SH-SY5Y neuroblastoma cells, LUHMES conditionally-immortalized dopaminergic neurons, and Neural Stem Cells (NSC) derived from human fetal brain. These three cell lines were evaluated for rapidity and degree of differentiation, and sensitivity to 32 known or candidate neurotoxicants. First, expression of neural differentiation genes was assayed during a 7-day differentiation period. Of the three cell lines, LUHMES showed the highest gene expression of neuronal markers after differentiation. Both in the undifferentiated state and after 7 days of neuronal differentiation, LUHMES cells exhibited greater cytotoxic sensitivity to most of 32 suspected or known neurotoxicants than SH-SY5Y or NSCs. LUHMES cells were also unique in being more susceptible to several compounds in the differentiating state than in the undifferentiated state; including known neurotoxicants colchicine, methyl-mercury (II), and vincristine. Gene expression results suggest that differentiating LUHMES cells may be susceptible to apoptosis because they express low levels of anti-apoptotic genes BCL2 and BIRC5/survivin, whereas SH-SY5Y cells may be resistant to apoptosis because they express high levels of BCL2, BIRC5/survivin, and BIRC3 genes. Thus, LUHMES cells exhibited favorable characteristics for neuro-cytotoxicity screening: rapid differentiation into neurons that exhibit high level expression neuronal marker genes, and marked sensitivity of LUHMES cells to known neurotoxicants. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Zhi-Bin Tong
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Helena Hogberg
- Centers for Alternatives to Animal Testing (CAAT) at Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, USA
| | - David Kuo
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Srilatha Sakamuru
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Menghang Xia
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Lena Smirnova
- Centers for Alternatives to Animal Testing (CAAT) at Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, USA
| | - Thomas Hartung
- Centers for Alternatives to Animal Testing (CAAT) at Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, USA.,University of Konstanz, POB 600, Konstanz, Germany
| | - David Gerhold
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
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Chauhan V, Chauhan A. Effects of methylmercury and alcohol exposure in Drosophila melanogaster: Potential risks in neurodevelopmental disorders. Int J Dev Neurosci 2016; 51:36-41. [PMID: 27151262 DOI: 10.1016/j.ijdevneu.2016.04.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/26/2016] [Accepted: 04/29/2016] [Indexed: 10/21/2022] Open
Abstract
Extensive evidence suggests the role of oxidative stress in autism and other neurodevelopmental disorders. In this study, we investigated whether methylmercury (MeHg) and/or alcohol exposure has deleterious effects in Drosophila melanogaster (fruit flies). A diet containing different concentrations of MeHg in Drosophila induced free radical generation and increased lipid peroxidation (markers of oxidative stress) in a dose-dependent manner. This effect of MeHg on oxidative stress was enhanced by further exposure to alcohol. It was observed that alcohol alone could also induce free radical generation in flies. After alcohol exposure, MeHg did not affect the immobilization of flies, but it increased the recovery time in a concentration-dependent manner. MeHg significantly inhibited the activity of alcohol dehydrogenase (ADH) in a dose-dependent manner. Linear regression analysis showed a significant negative correlation between ADH activity and recovery time upon alcohol exposure in the flies fed a diet with MeHg. This relationship between ADH activity and recovery time after alcohol exposure was confirmed by adding 4-methyl pyrazole (an inhibitor of ADH) to the diet for the flies. These results suggest that consumption of alcohol by pregnant mothers who are exposed to MeHg may lead to increased oxidative stress and to increased length of time for alcohol clearance, which may have a direct impact on the development of the fetus, thereby increasing the risk of neurodevelopmental disorders.
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Affiliation(s)
- Ved Chauhan
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA.
| | - Abha Chauhan
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
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Zeng X, Xu X, Boezen HM, Huo X. Children with health impairments by heavy metals in an e-waste recycling area. CHEMOSPHERE 2016; 148:408-15. [PMID: 26829309 DOI: 10.1016/j.chemosphere.2015.10.078] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 10/10/2015] [Accepted: 10/19/2015] [Indexed: 02/05/2023]
Abstract
E-waste recycling has become a global environmental health issue. Pernicious chemicals escape into the environment due to informal and nonstandard e-waste recycling activities involving manual dismantling, open burning to recover heavy metals and open dumping of residual fractions. Heavy metals derived from electronic waste (e-waste), such as, lead (Pb), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), mercury (Hg), arsenic (As), copper (Cu), zinc (Zn), aluminum (Al) and cobalt (Co), differ in their chemical composition, reaction properties, distribution, metabolism, excretion and biological transmission. Our previous studies showed that heavy metal exposure have adverse effects on children's health including lower birth weight, lower anogenital distance, lower Apgar scores, lower current weight, lower lung function, lower hepatitis B surface antibody levels, higher prevalence of attention-deficit/hyperactivity disorder, and higher DNA and chromosome damage. Heavy metals influence a number of diverse systems and organs, resulting in both acute and chronic effects on children's health, ranging from minor upper respiratory irritation to chronic respiratory, cardiovascular, nervous, urinary and reproductive disease, as well as aggravation of pre-existing symptoms and disease. These effects of heavy metals on children's health are briefly discussed.
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Affiliation(s)
- Xiang Zeng
- Laboratory of Environmental Medicine and Developmental Toxicology, and Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou University, 22 Xinling Road, Shantou 515041, China; Department of Epidemiology, University Medical Center Groningen, University of Groningen, 1 Hanzeplein, Groningen 9700RB, The Netherlands; Groningen Research Institute for Asthma and COPD (GRIAC), University Medical Center Groningen, University of Groningen, 1 Hanzeplein, Groningen 9700RB, The Netherlands
| | - Xijin Xu
- Laboratory of Environmental Medicine and Developmental Toxicology, and Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou University, 22 Xinling Road, Shantou 515041, China; Department of Cell Biology and Genetics, Shantou University Medical College, Shantou University, 22 Xinling Road, Shantou 515041, China
| | - H Marike Boezen
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, 1 Hanzeplein, Groningen 9700RB, The Netherlands; Groningen Research Institute for Asthma and COPD (GRIAC), University Medical Center Groningen, University of Groningen, 1 Hanzeplein, Groningen 9700RB, The Netherlands
| | - Xia Huo
- School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China.
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50
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Methylmercury affects cerebrovascular reactivity to angiotensin II and acetylcholine via Rho-kinase and nitric oxide pathways in mice. Life Sci 2016; 147:30-8. [DOI: 10.1016/j.lfs.2016.01.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 12/21/2015] [Accepted: 01/21/2016] [Indexed: 12/26/2022]
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