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Hassan A, Mohsen R, Rezk A, Bangay G, Rijo P, Soliman MFM, G. A. Hablas M, Swidan KAK, Mohammed TS, Zoair MA, Mohamed AAK, Abdalrhman TI, Abdel-aleem Desoky AM, Mohamed DD, Mohamed DD, Abd El Maksoud AI, Mohamed AF. Enhancement of Vitamin C's Protective Effect against Thimerosal-Induced Neurotoxicity in the Cerebral Cortex of Wistar Albino Rats: An In Vivo and Computational Study. ACS OMEGA 2024; 9:8973-8984. [PMID: 38434836 PMCID: PMC10905602 DOI: 10.1021/acsomega.3c07239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/29/2023] [Accepted: 01/09/2024] [Indexed: 03/05/2024]
Abstract
Vitamin C was examined to ameliorate the neurotoxicity of thimerosal (THIM) in an animal model (Wistar albino rats). In our work, oxidative and antioxidative biomarkers such as SOD, LPO, and GSH were investigated at various doses of THIM with or without concurrent vitamin C administration. Furthermore, the adverse effects of THIM on hepatic tissue and cerebral cortex morphology were examined in the absence or presence of associated vitamin C administration. Also, we studied the effect of vitamin C on the metallothionein isoforms (MT-1, MT-2, and MT-3) in silico and in vivo using the RT-PCR assay. The results showed that the antioxidant biomarker was reduced as the THIM dose was raised and vice versa. THIM-associated vitamin C reduced the adverse effects of the THIM dose. The computation studies demonstrated that vitamin C has a lower ΔG of -4.9 kcal/mol compared to -4.1 kcal/mol for THIM to bind to the MT-2 protein, which demonstrated that vitamin C has a greater ability to bind with MT-2 than THIM. This is due to multiple hydrogen bonds that exist between vitamin C and MT-2 residues Lys31, Gln23, Cys24, and Cys29, and the sodium ion represents key stabilizing interactions. Hydrogen bonds involve electrostatic interactions between hydrogen atom donors (e.g., hydroxyl groups) and acceptors (e.g., carbonyl oxygens). The distances between heavy atoms are typically 2.5-3.5 Å. H-bonds provide directed, high-affinity interactions to anchor the ligand to the binding site. The five H-bonds formed by vitamin C allow it to form a stable complex with MT, while THIM can form two H-bonds with Gln23 and Cys24. This provides less stabilization in the binding pocket, contributing to the lower affinity compared to vitamin C. The histopathological morphologies in hepatic tissue displayed an expansion in the portal tract and the hepatocytes surrounding the portal tract, including apoptosis, binucleation, and karyomegaly. The histopathological morphologies in the brain tissue revealed a significant decrease in the number of Purkinje cells due to THIM toxicity. Interestingly, THIM toxicity was associated with hemorrhage and astrogliosis. Both intracellular and vasogenic edema appeared as the concentrations of THIM rose. Finally, vitamin C ameliorated the adverse effect on the cerebral cortex in Wistar albino rats.
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Affiliation(s)
- Amr Hassan
- Department
of Bioinformatics, Genetic Engineering and Biotechnology Research
Institute (GEBRI), University of Sadat City, Sadat 32897, Egypt
| | - Reham Mohsen
- College
of Biotechnology, October University for Modern Science and Arts (MSA), University Giza, Giza 11456, Egypt
| | - Ahmed Rezk
- College
of Biotechnology, October University for Modern Science and Arts (MSA), University Giza, Giza 11456, Egypt
| | - Gabrielle Bangay
- CBIOS—Research
Center for Biosciences & Health Technologies, Universidade Lusófona de Humanidades e Tecnologias, Lisboa 1749-024, Portugal
- Facultad
de Farmacia, Departamento de Ciencias Biomédicas (Área
de Farmacología; Nuevos agentes antitumorales, Acción
tóxica sobre células leucémicas), Universidad de Alcalá de Henares, Ctra. Madrid-Barcelona km. 33, Alcalá de Henares 600 28805, Madrid, Espana
| | - Patrícia Rijo
- CBIOS—Research
Center for Biosciences & Health Technologies, Universidade Lusófona de Humanidades e Tecnologias, Lisboa 1749-024, Portugal
- Instituto
de Investigação do Medicamento (iMed.ULisboa), Faculdade
de Farmácia, Universidade de Lisboa, Lisbon 1749-024, Portugal
| | - Mona F. M. Soliman
- Department
of Histology and Cell Biology, Faculty Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Mohamed G. A. Hablas
- Department
of Histology and Cell Biology, Faculty of Medicine, Suez University, Suez 43221, Egypt
| | | | - Tahseen S. Mohammed
- Department
of Public Health and Community Medicine, Faculty of Medicine, Al-Azhar University, Cairo 11884, Egypt
| | - Mohammad A. Zoair
- Department
of Physiology, Faculty of Medicine, Al-Azhar
University, Cairo 11884, Egypt
| | - Abir A. Khalil Mohamed
- Department
of Zoology, Faculty of Science, Girls Branch, Al-Azhar University, Cairo 11884, Egypt
| | - Tamer I. Abdalrhman
- Department of Histology, Faculty of Medicine, Al-Azhar University, Assiut 71524, Egypt
| | | | - Dalia D. Mohamed
- Department of Industrial Biotechnology,
Genetic Engineering and Biotechnology
Research Institute (GEBRI), University of
Sadat City, Sadat 32897, Egypt
| | - Doaa D. Mohamed
- Department of Industrial Biotechnology,
Genetic Engineering and Biotechnology
Research Institute (GEBRI), University of
Sadat City, Sadat 32897, Egypt
| | - Ahmed I. Abd El Maksoud
- Department of Industrial Biotechnology,
Genetic Engineering and Biotechnology
Research Institute (GEBRI), University of
Sadat City, Sadat 32897, Egypt
| | - Aly F. Mohamed
- Holding
Company for Vaccine and Sera Production (VACSERA), Giza 22311, Egypt
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Salpin J, Haldys V, Guillemin J, Mó O, Yáñez M, Montero‐Campillo MM. Reactivity of Cytosine with Alkylmercury Ions in the Gas Phase: the Critical Role of the Alkyl Chain. Isr J Chem 2023. [DOI: 10.1002/ijch.202300014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Affiliation(s)
- Jean‐Yves Salpin
- Université Paris-Saclay Univ Evry CY Cergy Paris Université CNRS LAMBE 91025 Evry-Courcouronnes France
| | - Violette Haldys
- Université Paris-Saclay Univ Evry CY Cergy Paris Université CNRS LAMBE 91025 Evry-Courcouronnes France
| | - Jean‐Claude Guillemin
- Univ Rennes Ecole Nationale Supérieure de Chimie de Rennes CNRS ISCR – UMR6226 F-35000 Rennes France
| | - Otilia Mó
- Departamento de Química, Módulo 13 Facultad de Ciencias, and Institute of Advanced Chemical Sciences (IAdChem) Universidad Autónoma de Madrid Campus de Excelencia UAM-CSIC Cantoblanco, 28049 Madrid Spain
| | - Manuel Yáñez
- Departamento de Química, Módulo 13 Facultad de Ciencias, and Institute of Advanced Chemical Sciences (IAdChem) Universidad Autónoma de Madrid Campus de Excelencia UAM-CSIC Cantoblanco, 28049 Madrid Spain
| | - M. Merced Montero‐Campillo
- Departamento de Química, Módulo 13 Facultad de Ciencias, and Institute of Advanced Chemical Sciences (IAdChem) Universidad Autónoma de Madrid Campus de Excelencia UAM-CSIC Cantoblanco, 28049 Madrid Spain
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Yu X, Tian X, Wang Y, Zhu C. Metal-metal interaction and metal toxicity: a comparison between mammalian and D. melanogaster. Xenobiotica 2021; 51:842-851. [PMID: 33929283 DOI: 10.1080/00498254.2021.1922781] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
1. Non-essential heavy metals such as mercury (Hg), arsenic (As), cadmium (Cd), and aluminium (Al) are useless to organisms and have shown extensive toxic effects. Previous studies show that two main molecular mechanisms of metal toxicity are oxidative stress and metal-metal interaction which can disrupt metal homeostasis.2. In this paper, we mainly illustrate metal toxicity and metal-metal interaction through examples in mammalians and D. melanogaster (fruit fly).3. We describe the interference of metal homeostasis by metal-metal interactions in three aspects including replacement, cellular transporter competition, and disruption of the regulation mechanism, and elaborate the mechanisms of metal toxicity to better deal with the challenges of heavy metal pollution and related health problems.
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Affiliation(s)
- Xiaoyu Yu
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Xianhan Tian
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Yiwen Wang
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Chunfeng Zhu
- School of Life Sciences, Tianjin University, Tianjin, China
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Chen N, Tang X, Ye Z, Wang S, Xiao X. Methylmercury disrupts autophagic flux by inhibiting autophagosome-lysosome fusion in mouse germ cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 198:110667. [PMID: 32339925 DOI: 10.1016/j.ecoenv.2020.110667] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 04/03/2020] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
Methylmercury (MeHg) is an extremely toxic environmental pollutant that can cause serious male reproductive developmental dysplasia in humans and animals. However, the molecular mechanisms underlying MeHg-induced male reproductive injury are not fully clear. The purpose of this study was to explore whether mitophagy and lysosome dysfunction contribute to MeHg-induced apoptosis of germ cell and to determine the potential mechanism. First, we confirmed the exposure of GC2-spd cells to mercury. In GC2-spd cells (a mouse spermatocyte cell line), we found that MeHg treatment led to an obvious increase of cell apoptosis accompanied by a marked rise of LC3-II expression and an elevated number of autophagosomes. These results were associated with the induction of oxidative stress and mitophagy. Interestingly, we found that MeHg did not promote but prevented autophagosome-lysosome fusion by impairing the lysosome function. Furthermore, as a lysosome inhibitor, chloroquine pre-treatment obviously enhanced LC3-II expression and mitophagy formation in MeHg-treated cells. This further proved that the induction of mitophagy and the injury of the lysosome played an important role in the GC2-spd cell apoptosis induced by MeHg. Our findings indicate that MeHg caused apoptosis in the GC2-spd cells, which were dependent on oxidative stress-mediated mitophagy and the lysosome damaging-mediated inhibition of autophagic flux induced by MeHg.
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Affiliation(s)
- Na Chen
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Xiaofeng Tang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Zhaoyang Ye
- Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Shanshan Wang
- Key Laboratory of Agro-product Safety and Quality, Institute of Quality Standards & Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing, 100081, PR China.
| | - Xianjin Xiao
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China.
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Xu L, Shi Q, Tang BC, Xie S. A New Plant Indicator ( Artemisia lavandulaefolia DC.) of Mercury in Soil Developed by Fourier-Transform Near-Infrared Spectroscopy Coupled with Least Squares Support Vector Machine. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2019; 2019:3240126. [PMID: 31583158 PMCID: PMC6754876 DOI: 10.1155/2019/3240126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/17/2019] [Indexed: 06/10/2023]
Abstract
A rapid indicator of mercury in soil using a plant (Artemisia lavandulaefolia DC., ALDC) commonly distributed in mercury mining area was established by fusion of Fourier-transform near-infrared (FT-NIR) spectroscopy coupled with least squares support vector machine (LS-SVM). The representative samples of ALDC (stem and leaf) were gathered from the surrounding and distant areas of the mercury mines. As a reference method, the total mercury contents in soil and ALDC samples were determined by a direct mercury analyzer incorporating high-temperature decomposition, catalytic adsorption for impurity removal, amalgamation capture, and atomic absorption spectrometry (AAS). Based on the FT-NIR data of ALDC samples, LS-SVM models were established to distinguish mercury-contaminated and ordinary soil. The results of reference analysis showed that the mercury level of the areas surrounding mercury mines (0-3 kilometers, 7.52-88.59 mg/kg) was significantly higher than that of the areas distant from mercury mines (>5 kilometers, 0-0.75 mg/kg). The LS-SVM classification model of ALDC samples was established based on the original spectra, smoothed spectra, second-derivative (D2) spectra, and standard normal transformation (SNV) spectra, respectively. The prediction accuracy of D2-LS-SVM was the highest (0.950). FT-NIR combined with LS-SVM modeling can quickly and accurately identify the contaminated ALDC. Compared with traditional methods which rely on naked eye observation of plants, this method is objective and more sensitive and applicable.
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Affiliation(s)
- Lu Xu
- College of Material and Chemical Engineering, Tongren University, Tongren 554300, Guizhou, China
| | - Qiong Shi
- The Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei Province, College of Pharmacy, South-Central University for Nationalities, Wuhan 430074, China
| | - Bang-Cheng Tang
- College of Material and Chemical Engineering, Tongren University, Tongren 554300, Guizhou, China
| | - Shunping Xie
- Technology Center, China Tobacco Guizhou Industrial Co., Ltd., Guiyang 550009, Guizhou, China
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6
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Pan SL, Li K, Li LL, Li MY, Shi L, Liu YH, Yu XQ. A reaction-based ratiometric fluorescent sensor for the detection of Hg(ii) ions in both cells and bacteria. Chem Commun (Camb) 2018; 54:4955-4958. [PMID: 29701217 DOI: 10.1039/c8cc01031e] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A novel reaction-based fluorescent probe (ATC-Hg) was designed and synthesized via the "covalent assembly" principle, which exhibited excellent selectivity and high sensitivity for Hg2+ and CH3Hg+. Moreover, it is the first Hg(ii) sensitive fluorescent probe that has been successfully applied in imaging in both cells and Escherichia coli.
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Affiliation(s)
- Sheng-Lin Pan
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry Sichuan University, 29, Wangjiang Road, Chengdu, Sichuan Province, China.
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Shirkhanloo H, Fallah Mehrjerdi MA, Hassani H. Identifying occupational and nonoccupational exposure to mercury in dental personnel. ARCHIVES OF ENVIRONMENTAL & OCCUPATIONAL HEALTH 2017; 72:63-69. [PMID: 25257992 DOI: 10.1080/19338244.2014.964391] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 08/30/2014] [Indexed: 05/24/2023]
Abstract
The objective of this study was to investigate the occupational and nonoccupational exposure to mercury (Hg) vapor in dental personnel by examining the relationships between blood mercury, urine mercury, and their ratio with air mercury. The method was performed on 50 occupational exposed and 50 unexposed controls (25 men and 25 women). The mercury concentrations in air and human biological samples were determined based on the National Institute for Occupational Safety and Health (NIOSH) method and standard method (SM) by a new mode of liquid-phase microextraction, respectively. The mean mercury concentrations in urine (μg Hg0/g creatinine) and blood were significantly higher than control group, respectively (19.41 ± 5.18 vs 2.15 ± 0.07 μg/g and 16.40 ± 4.97 vs 2.50 ± 0.02 μg/L) (p <.001). The relationships between mercury concentration in blood/urine ratio (r = .380) with dental office air are new indicators for assessing occupational exposure in dental personnel.
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Affiliation(s)
- Hamid Shirkhanloo
- a Iranian Petroleum Industry Occupational and Environmental Health Research Center (IPIOEHRC), Iranian Petroleum Industry Health Research Institute (IPIHRI) , Tehran , Iran
| | | | - Hamid Hassani
- a Iranian Petroleum Industry Occupational and Environmental Health Research Center (IPIOEHRC), Iranian Petroleum Industry Health Research Institute (IPIHRI) , Tehran , Iran
- c Department of Occupational Health Engineering , School of Public Health, Tehran University of Medical Sciences , Tehran , Iran
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8
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Ortega-Atienza S, Rubis B, McCarthy C, Zhitkovich A. Formaldehyde Is a Potent Proteotoxic Stressor Causing Rapid Heat Shock Transcription Factor 1 Activation and Lys48-Linked Polyubiquitination of Proteins. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2857-2868. [PMID: 27639166 DOI: 10.1016/j.ajpath.2016.06.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 05/24/2016] [Accepted: 06/30/2016] [Indexed: 11/29/2022]
Abstract
Endogenous and exogenous formaldehyde (FA) has been linked to cancer, neurotoxicity, and other pathophysiologic effects. Molecular and cellular mechanisms that underlie FA-induced damage are poorly understood. In this study, we investigated whether proteotoxicity is an important, unrecognized factor in cell injury caused by FA. We found that irrespective of their cell cycle phases, all FA-treated human cells rapidly accumulated large amounts of proteins with proteasome-targeting K48-linked polyubiquitin, which was comparable with levels of polyubiquitination in proteasome-inhibited MG132 controls. Both nuclear and cytoplasmic proteins were damaged and underwent K48-polyubiquitination. There were no significant changes in the nonproteolytic K63-polyubiquitination of soluble and insoluble cellular proteins. FA also rapidly induced nuclear accumulation and Ser326 phosphorylation of the main heat shock-responsive transcription factor HSF1, which was not a result of protein polyubiquitination. Consistent with the activation of the functional heat shock response, FA strongly elevated the expression of HSP70 genes. In contrast to the responsiveness of the cytoplasmic protein damage sensor HSF1, FA did not activate the unfolded protein response in either the endoplasmic reticulum or mitochondria. Inhibition of HSP90 chaperone activity increased the levels of K48-polyubiquitinated proteins and diminished cell viability after FA treatment. Overall, our results indicate that FA is a strong proteotoxic agent, which helps explain its diverse pathologic effects, including injury in nonproliferative tissues.
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Affiliation(s)
- Sara Ortega-Atienza
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island
| | - Blazej Rubis
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island
| | - Caitlin McCarthy
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island
| | - Anatoly Zhitkovich
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island.
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Wang S, Lv Q, Yang Y, Guo LH, Wan B, Ren X, Zhang H. Arginine decarboxylase: A novel biological target of mercury compounds identified in PC12 cells. Biochem Pharmacol 2016; 118:109-120. [PMID: 27565891 DOI: 10.1016/j.bcp.2016.08.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 08/22/2016] [Indexed: 01/28/2023]
Abstract
Mercury compounds are well-known toxic environmental pollutants and potently induce severe neurotoxicological effects in human and experimental animals. Previous studies showed that one of the mechanisms of mercury compounds neurotoxicity arose from the over-activation of the N-methyl d-aspartate (NMDA)-type glutamate receptor induced by increased glutamate release. In this work, we aimed to investigate the molecular mechanisms of Hg compounds neurotoxicities by identifying their biological targets in cells. Firstly, the inhibitory effects of four Hg compounds, including three organic (methyl-, ethyl- and phenyl-mercury) and one inorganic (Hg2+) Hg compounds, on the activity of arginine decarboxylase (ADC), a key enzyme in the central agmatinergic system, were evaluated. They were found to inhibit the ADC activity significantly with methylmercury (MeHg) being the strongest (IC50=7.96nM). Furthermore, they showed remarkable inhibitory effects on ADC activity in PC12 cells (MeHg>EtHg>PhHg>HgCl2), and led to a marked loss in the level of agmatine, an endogenous neuromodulatory and neuroprotective agent that selectively blocks the activation of NMDA receptors. MeHg was detected in the immunoprecipitated ADC from the cells, providing unequivocal evidence for the direct binding of MeHg with ADC in the cell. Molecular dynamics simulation revealed that Hg compounds could form the coordination bond not only with cofactor PLP of ADC, but also with substrate arginine. Our finding indicated that MeHg could attenuate the neuroprotective effects of agmatine by the inhibition of ADC, a new cellular target of MeHg, which might be implicated in molecular mechanism of MeHg neurotoxicity.
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Affiliation(s)
- Sufang Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18 Shuangqing Road, Beijing 100085, China; College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Qiyan Lv
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18 Shuangqing Road, Beijing 100085, China
| | - Yu Yang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18 Shuangqing Road, Beijing 100085, China.
| | - Liang-Hong Guo
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18 Shuangqing Road, Beijing 100085, China; Institute of Environment and Health, Jianghan University, Wuhan 430056, China.
| | - Bin Wan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18 Shuangqing Road, Beijing 100085, China
| | - Xiaomin Ren
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18 Shuangqing Road, Beijing 100085, China
| | - Hui Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18 Shuangqing Road, Beijing 100085, China
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Díaz de Greñu B, García-Calvo J, Cuevas J, García-Herbosa G, García B, Busto N, Ibeas S, Torroba T, Torroba B, Herrera A, Pons S. Chemical speciation of MeHg + and Hg 2+ in aqueous solution and HEK cells nuclei by means of DNA interacting fluorogenic probes. Chem Sci 2015; 6:3757-3764. [PMID: 29218145 PMCID: PMC5707467 DOI: 10.1039/c5sc00718f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 04/30/2015] [Indexed: 12/15/2022] Open
Abstract
Selected new fluorogenic probes that interact in different ways with Hg2+ and MeHg+ have been prepared and used for the chemical speciation of both cations in aqueous solution as well as in HEK293 cells. The best selective speciation of Hg2+ and MeHg+ has been achieved by in vitro approaches based on fluorogenic probes supported in cultured cells, due to the particular sensitivity of the HEK293 cells to permeation by Hg2+, MeHg+ and the fluorogenic probes. In particular, MeHg+ was selectively detected in cell nuclei by probe JG45.
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Affiliation(s)
- Borja Díaz de Greñu
- Department of Chemistry , Faculty of Science , University of Burgos , 09001 Burgos , Spain .
| | - José García-Calvo
- Department of Chemistry , Faculty of Science , University of Burgos , 09001 Burgos , Spain .
| | - José Cuevas
- Department of Chemistry , Faculty of Science , University of Burgos , 09001 Burgos , Spain .
| | - Gabriel García-Herbosa
- Department of Chemistry , Faculty of Science , University of Burgos , 09001 Burgos , Spain .
| | - Begoña García
- Department of Chemistry , Faculty of Science , University of Burgos , 09001 Burgos , Spain .
| | - Natalia Busto
- Department of Chemistry , Faculty of Science , University of Burgos , 09001 Burgos , Spain .
| | - Saturnino Ibeas
- Department of Chemistry , Faculty of Science , University of Burgos , 09001 Burgos , Spain .
| | - Tomás Torroba
- Department of Chemistry , Faculty of Science , University of Burgos , 09001 Burgos , Spain .
| | - Blanca Torroba
- Molecular Biology Institute of Barcelona , IBMB-CSIC , Barcelona Science Park , 08028 Barcelona , Spain
| | - Antonio Herrera
- Molecular Biology Institute of Barcelona , IBMB-CSIC , Barcelona Science Park , 08028 Barcelona , Spain
| | - Sebastian Pons
- Molecular Biology Institute of Barcelona , IBMB-CSIC , Barcelona Science Park , 08028 Barcelona , Spain
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11
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Amaroli A. The Effects of Temperature Variation on the Sensitivity to Pesticides: a Study on the Slime Mould Dictyostelium discoideum (Protozoa). MICROBIAL ECOLOGY 2015; 70:244-254. [PMID: 25515424 DOI: 10.1007/s00248-014-0541-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
Slime moulds live in agricultural ecosystems, where they play an important role in the soil fertilization and in the battle against crop pathogens. In an agricultural soil, the amoebae are exposed to different stress factors such as pesticides and weather conditions. The use of pesticides increased up from 0.49 kg per hectare in 1961 to 2 kg in 2004, and the global greenhouse gas emission has grown 70% between 1970 and 2004 leading to a global fluctuation of average surface temperature. Therefore, the European Directive 2009/128/EC has led to a new approach to agriculture, with the transition from an old concept based on high use of pesticides and fossil fuels to an agriculture aware of biodiversity and health issues. We studied the effects of temperature variations and pesticides on Dictyostelium discoideum. We measured the fission rate, the ability to differentiate and the markers of stress such as the activity and presence of pseudocholinesterase and the presence of heat shock protein 70. Our results highlight how the sensitivity to zinc, aluminium, silver, copper, cadmium, mercury, diazinon and dicofol changes for a 2 °C variation from nothing/low to critical. Our work suggests considering, in future regulations, about the use of pesticides as their toxic effect on non-target organisms is strongly influenced by climate temperatures. In addition, there is a need for a new consideration of the protozoa, which takes into account recent researches about the presence in this microorganism of classical neurotransmitters that, similar to those in animals, make protozoa an innocent target of neurotoxic pesticides in the battle against the pest crops.
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Affiliation(s)
- Andrea Amaroli
- Dipartimento di Scienze della Terra dell'Ambiente e della Vita (DISTAV), University of Genoa, Corso Europa 26, 16132, Genoa, Italy,
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Alcaide B, Almendros P, Luna A, Soriano E. An Alternative to Precious Metals: Hg(ClO4)2·3H2O as a Cheap and Water-Tolerant Catalyst for the Cycloisomerization of Allenols. J Org Chem 2015; 80:7050-7. [PMID: 26079496 DOI: 10.1021/acs.joc.5b00887] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Benito Alcaide
- Grupo
de Lactamas y Heterociclos Bioactivos, Departamento de Química
Orgánica I, Unidad Asociada al CSIC, Facultad de Química, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Pedro Almendros
- Instituto de Química Orgánica General, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
| | - Amparo Luna
- Grupo
de Lactamas y Heterociclos Bioactivos, Departamento de Química
Orgánica I, Unidad Asociada al CSIC, Facultad de Química, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Elena Soriano
- Instituto de Química Orgánica General, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
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13
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Kern JK, Geier DA, King PG, Sykes LK, Mehta JA, Geier MR. Shared Brain Connectivity Issues, Symptoms, and Comorbidities in Autism Spectrum Disorder, Attention Deficit/Hyperactivity Disorder, and Tourette Syndrome. Brain Connect 2015; 5:321-35. [PMID: 25602622 DOI: 10.1089/brain.2014.0324] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The prevalence of neurodevelopmental disorders, including autism spectrum disorder (ASD), attention deficit/hyperactivity disorder (ADHD), and Tourette syndrome (TS), has increased over the past two decades. Currently, about one in six children in the United States is diagnosed as having a neurodevelopmental disorder. Evidence suggests that ASD, ADHD, and TS have similar neuropathology, which includes long-range underconnectivity and short-range overconnectivity. They also share similar symptomatology with considerable overlap in their core and associated symptoms and a frequent overlap in their comorbid conditions. Consequently, it is apparent that ASD, ADHD, and TS diagnoses belong to a broader spectrum of neurodevelopmental illness. Biologically, long-range underconnectivity and short-range overconnectivity are plausibly related to neuronal insult (e.g., neurotoxicity, neuroinflammation, excitotoxicity, sustained microglial activation, proinflammatory cytokines, toxic exposure, and oxidative stress). Therefore, these disorders may a share a similar etiology. The main purpose of this review is to critically examine the evidence that ASD, ADHD, and TS belong to a broader spectrum of neurodevelopmental illness, an abnormal connectivity spectrum disorder, which results from neural long-range underconnectivity and short-range overconnectivity. The review also discusses the possible reasons for these neuropathological connectivity findings. In addition, this review examines the role and issue of axonal injury and regeneration in order to better understand the neuropathophysiological interplay between short- and long-range axons in connectivity issues.
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Affiliation(s)
- Janet K Kern
- 1 Institute of Chronic Illnesses, Inc. , Silver Spring, Maryland
| | - David A Geier
- 1 Institute of Chronic Illnesses, Inc. , Silver Spring, Maryland
| | | | | | - Jyutika A Mehta
- 3 Communication Sciences & Disorders, Texas Woman's University , Denton, Texas
| | - Mark R Geier
- 1 Institute of Chronic Illnesses, Inc. , Silver Spring, Maryland
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14
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Hodgson NW, Waly MI, Al-Farsi YM, Al-Sharbati MM, Al-Farsi O, Ali A, Ouhtit A, Zang T, Zhou ZS, Deth RC. Decreased glutathione and elevated hair mercury levels are associated with nutritional deficiency-based autism in Oman. Exp Biol Med (Maywood) 2014; 239:697-706. [DOI: 10.1177/1535370214527900] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Genetic, nutrition, and environmental factors have each been implicated as sources of risk for autism. Oxidative stress, including low plasma levels of the antioxidant glutathione, has been reported by numerous autism studies, which can disrupt methylation-dependent epigenetic regulation of gene expression with neurodevelopmental consequences. We investigated the status of redox and methylation metabolites, as well as the level of protein homocysteinylation and hair mercury levels, in autistic and neurotypical control Omani children, who were previously shown to exhibit significant nutritional deficiencies in serum folate and vitamin B12. The serum level of glutathione in autistic subjects was significantly below control levels, while levels of homocysteine and S-adenosylhomocysteine were elevated, indicative of oxidative stress and decreased methionine synthase activity. Autistic males had lower glutathione and higher homocysteine levels than females, while homocysteinylation of serum proteins was increased in autistic males but not females. Mercury levels were markedly elevated in the hair of autistic subjects vs. control subjects, consistent with the importance of glutathione for its elimination. Thus, autism in Oman is associated with decreased antioxidant resources and decreased methylation capacity, in conjunction with elevated hair levels of mercury.
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Affiliation(s)
- Nathaniel W Hodgson
- Department of Pharmaceutical Sciences, Bouve College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Mostafa I Waly
- Department of Food Science and Nutrition, Sultan Qaboos University, P.O.Box 34, P.C. 123, Al-Khoud, Muscat, Sultanate of Oman
- Nutrition Department, High Institute of Public Health, Alexandria University, P.C. 165, El-Hadra, Alexandria, Egypt
| | - Yahya M Al-Farsi
- Department of Family Medicine and Public Health, College of Medicine and Health Sciences, Sultan Qaboos University, P.O.Box 35, P.C. 123, Al-Khoud, Muscat, Sultanate of Oman
- Department of Epidemiology, School of Public Health, Boston University, Boston, MA 02118, USA
| | - Marwan M Al-Sharbati
- Department of Behavioral Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, Al-Khoud 123, Muscat, Sultanate of Oman
| | - Omar Al-Farsi
- Department of Family Medicine and Public Health, College of Medicine and Health Sciences, Sultan Qaboos University, P.O.Box 35, P.C. 123, Al-Khoud, Muscat, Sultanate of Oman
| | - Amanat Ali
- Department of Food Science and Nutrition, Sultan Qaboos University, P.O.Box 34, P.C. 123, Al-Khoud, Muscat, Sultanate of Oman
| | - Allal Ouhtit
- Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University, Al-Khoud 123, Muscat, Sultanate of Oman
| | - Tianzhu Zang
- Barnett Institute of Chemical and Biological Analysis, College of Science, Northeastern University, Boston, MA 02115, USA
| | - Zhaohui Sunny Zhou
- Barnett Institute of Chemical and Biological Analysis, College of Science, Northeastern University, Boston, MA 02115, USA
| | - Richard C Deth
- Department of Pharmaceutical Sciences, Bouve College of Health Sciences, Northeastern University, Boston, MA 02115, USA
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15
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Reaction of Hg2+ Insertion into Cysteine Pairs Within Bovine Insulin Crystals Followed via Raman Spectroscopy. J SOLUTION CHEM 2013. [DOI: 10.1007/s10953-013-0066-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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16
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Scientific Opinion on the risk for public health related to the presence of mercury and methylmercury in food. EFSA J 2012. [DOI: 10.2903/j.efsa.2012.2985] [Citation(s) in RCA: 276] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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17
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Tseng CW, Chang HY, Chang JY, Huang CC. Detection of mercury ions based on mercury-induced switching of enzyme-like activity of platinum/gold nanoparticles. NANOSCALE 2012; 4:6823-30. [PMID: 23011048 DOI: 10.1039/c2nr31716h] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In this study, bimetallic platinum/gold nanoparticles (Pt/Au NPs) were found to exhibit peroxidase-like activity, and the deposition of mercury was found to switch the enzymatic activity to a catalase-like activity. Based on this phenomenon, we developed a new method for detecting mercury ions through their deposition on bimetallic Pt/Au NPs to switch the catalytic activity of Pt/Au NPs. Pt/Au NPs could be easily prepared through reduction of Au(3+) and Pt(4+) by sodium citrate in a one-pot synthesis. The peroxidase catalytic activity of the Pt/Au NPs was controlled by varying the ratios of Pt to Au. The Pt(0.1)/Au NPs (prepared with a [Au(3+)]/[Pt(4+)] molar ratio of 9.0/1.0) showed excellent oxidation catalysis for H(2)O(2)-mediated oxidation of Amplex® Red (AR) to resorufin. The oxidized product of AR, resorufin, fluoresces more strongly (excitation/emission wavelength maxima ca. 570/585 nm) than AR alone. The peroxidase catalytic activity of Pt(0.1)/Au NPs was switched to catalase-like activity in the presence of mercury ions in a 5.0 mM tris(hydroxymethyl)aminomethane (Tris)-borate solution (pH 7.0) through the deposition of Hg on the particle surfaces owing to the strong Hg-Au metallic bond. The catalytic activity of Hg-Pt(0.1)/Au NPs is superior (by at least 5-fold) to that of natural catalase (from bovine liver). Under optimal solution conditions [5.0 mM Tris-borate (pH 7.0), H(2)O(2) (50 mM), and AR (10 μM)] and in the presence of the masking agents polyacrylic acid and tellurium nanowires, the Pt(0.1)/Au NPs allowed the selective detection of inorganic mercury (Hg(2+)) and methylmercury ions (MeHg(+)) at concentrations as low as several nanomolar. This simple, fast, and cost-effective system enabled selective determination of the spiked concentrations of Hg(2+) and MeHg(+) in tap, pond, and stream waters.
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Affiliation(s)
- Chao-Wei Tseng
- Institute of Bioscience and Biotechnology, Center of Excellence for Marine Bioenvironment and Biotechnology, National Taiwan Ocean University, 2, Pei-Ning Road, Keelung, 20224, Taiwan
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18
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Syversen T, Kaur P. The toxicology of mercury and its compounds. J Trace Elem Med Biol 2012; 26:215-26. [PMID: 22658719 DOI: 10.1016/j.jtemb.2012.02.004] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 02/07/2012] [Indexed: 12/27/2022]
Abstract
A concentrated review on the toxicology of inorganic mercury together with an extensive review on the neurotoxicology of methylmercury is presented. The challenges of using inorganic mercury in dental amalgam are reviewed both regarding the occupational exposure and the possible health problems for the dental patients. The two remaining "mysteries" of methylmercury neurotoxicology are also being reviewed; the cellular selectivity and the delayed onset of symptoms. The relevant literature on these aspects has been discussed and some suggestions towards explaining these observations have been presented.
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Affiliation(s)
- Tore Syversen
- Norwegian University of Science and Technology, Department of Neuroscience, Trondheim, Norway.
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19
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Silver(I), mercury(II), cadmium(II), and zinc(II) target exposed enzymic iron-sulfur clusters when they toxify Escherichia coli. Appl Environ Microbiol 2012; 78:3614-21. [PMID: 22344668 DOI: 10.1128/aem.07368-11] [Citation(s) in RCA: 189] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The toxicity of soft metals is of broad interest to microbiologists, both because such metals influence the community structures in natural environments and because several metals are used as antimicrobial agents. Their potency roughly parallels their thiophilicity, suggesting that their primary biological targets are likely to be enzymes that contain key sulfhydryl moieties. A recent study determined that copper poisons Escherichia coli in part by attacking the exposed [4Fe-4S] clusters of dehydratases. The present investigation sought to test whether other soft metals also target these enzymes. In vitro experiments revealed that low-micromolar concentrations of Ag(I) and Hg(II) directly inactivated purified fumarase A, a member of the dehydratase family. The enzyme was also poisoned by higher levels of Cd(II) and Zn(II), but it was unaffected by even millimolar concentrations of Mn(II), Co(II), Ni(II), and Pb(II). Electron paramagnetic resonance analysis and measurements of released iron confirmed that damage was associated with destruction of the [4Fe-4S] cluster, and indeed, the reconstruction of the cluster fully restored activity. Growth studies were then performed to test whether dehydratase damage might underlie toxicity in vivo. Barely toxic doses of Ag(I), Hg(II), Cd(II), and Zn(II) inactivated all tested members of the [4Fe-4S] dehydratase family. Again, activity was recovered when the clusters were rebuilt. The metals did not diminish the activities of other sampled enzymes, including NADH dehydrogenase I, an iron-sulfur protein whose clusters are shielded by polypeptide. Thus, the data indicate that dehydratases are damaged by the concentrations of metals that initiate bacteriostasis.
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Martinez-Finley EJ, Chakraborty S, Fretham SJB, Aschner M. Cellular transport and homeostasis of essential and nonessential metals. Metallomics 2012; 4:593-605. [PMID: 22337135 DOI: 10.1039/c2mt00185c] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Metals can have a number of detrimental or beneficial effects in the cell, but first they must get in. Organisms have evolved transport mechanisms to get metals that are required, or essential into the cell. Nonessential metals often enter the cell through use of the machinery provided for essential metals. Much work has been done to advance our understanding of how these metals are transported across plasma and organelle membranes. This review provides an overview of essential and nonessential metal transport and homeostatic processes.
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Affiliation(s)
- Ebany J Martinez-Finley
- Department of Pediatrics, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, TN, USA
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21
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Zhang Y, Lu R, Liu W, Wu Y, Qian H, Zhao X, Wang S, Xing G, Yu F, Aschner M. Hormetic effects of acute methylmercury exposure on grp78 expression in rat brain cortex. Dose Response 2012; 11:109-20. [PMID: 23549286 DOI: 10.2203/dose-response.11-055.rongzhu] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
This study aims to explore the expression of GRP78, a marker of endoplasmic reticulum (ER) stress, in the cortex of rat brains acutely exposed to methylmercury (MeHg). Thirty Sprague-Dawley (SD) rats were randomly divided into six groups, and decapitated 6 hours (h) after intraperitoneal (i.p.) injection of MeHg (2, 4, 6, 8 or 10 mg/kg body weight) or normal saline. Protein and mRNA expression of Grp78 were detected by western blotting and real-time PCR, respectively. The results showed that a gradual increase in GRP78 protein expression was observed in the cortex of rats acutely exposed to MeHg (2, 4 or 6 mg/kg). Protein levels peaked in the 6 mg/kg group (p < 0.05 vs. controls), decreased in the 8 mg/kg group, and bottomed below the control level in the 10 mg/kg group. Parallel changes were noted for Grp78 mRNA expression. It may be implied that acute exposure to MeHg induced hormetic dose-dependent changes in Grp78 mRNA and protein expression, suggesting that activation of ER stress is involved in MeHg-induced neurotoxicity. Low level MeHg exposure may induce GRP78 protein expression to stimulate endogenous cytoprotective mechanisms.
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Affiliation(s)
- Ye Zhang
- Department of Preventive Medicine, School of Medical Science and Laboratory Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
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22
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Owens SE, Summar ML, Ryckman KK, Haines JL, Reiss S, Summar SR, Aschner M. Lack of association between autism and four heavy metal regulatory genes. Neurotoxicology 2011; 32:769-75. [PMID: 21798283 PMCID: PMC3206176 DOI: 10.1016/j.neuro.2011.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 07/07/2011] [Accepted: 07/08/2011] [Indexed: 11/29/2022]
Abstract
Autism is a common neurodevelopmental disorder with genetic and environmental components. Though unproven, genetic susceptibility to high mercury (Hg) body burden has been suggested as an autism risk factor in a subset of children. We hypothesized that exposure to "safe" Hg levels could be implicated in the etiology of autism if genetic susceptibility altered Hg's metabolism or intracellular compartmentalization. Genetic sequences of four genes implicated in the transport and response to Hg were screened for variation and association with autism. LAT1 and DMT1 function in Hg transport, and Hg exposure induces MTF1 and MT1a. We identified and characterized 74 variants in MT1a, DMT1, LAT1 and MTF1. Polymorphisms identified through screening 48 unrelated individuals from the general and autistic populations were evaluated for differences in allele frequencies using Fisher's exact test. Three variants with suggestive p-values <0.1 and four variants with significant p-values <0.05 were followed-up with TaqMan genotyping in a larger cohort of 204 patients and 323 control samples. The pedigree disequilibrium test was used to examine linkage and association. Analysis failed to show association with autism for any variant evaluated in both the initial screening set and the expanded cohort, suggesting that variations in the ability of the four genes studied to process and transport Hg may not play a significant role in the etiology of autism.
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Affiliation(s)
- Sarah E. Owens
- Department of Pediatric Toxicology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Marshall L. Summar
- Center for Human Genetics Research, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Kelli K. Ryckman
- Center for Human Genetics Research, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jonathan L. Haines
- Center for Human Genetics Research, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Sara Reiss
- Center for Human Genetics Research, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Samantha R. Summar
- Center for Human Genetics Research, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Michael Aschner
- Department of Pediatric Toxicology, Vanderbilt University School of Medicine, Nashville, TN, USA
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23
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Farina M, Aschner M, Rocha JBT. Oxidative stress in MeHg-induced neurotoxicity. Toxicol Appl Pharmacol 2011; 256:405-17. [PMID: 21601588 PMCID: PMC3166649 DOI: 10.1016/j.taap.2011.05.001] [Citation(s) in RCA: 241] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/01/2011] [Accepted: 05/02/2011] [Indexed: 12/20/2022]
Abstract
Methylmercury (MeHg) is an environmental toxicant that leads to long-lasting neurological and developmental deficits in animals and humans. Although the molecular mechanisms mediating MeHg-induced neurotoxicity are not completely understood, several lines of evidence indicate that oxidative stress represents a critical event related to the neurotoxic effects elicited by this toxicant. The objective of this review is to summarize and discuss data from experimental and epidemiological studies that have been important in clarifying the molecular events which mediate MeHg-induced oxidative damage and, consequently, toxicity. Although unanswered questions remain, the electrophilic properties of MeHg and its ability to oxidize thiols have been reported to play decisive roles to the oxidative consequences observed after MeHg exposure. However, a close examination of the relationship between low levels of MeHg necessary to induce oxidative stress and the high amounts of sulfhydryl-containing antioxidants in mammalian cells (e.g., glutathione) have led to the hypothesis that nucleophilic groups with extremely high affinities for MeHg (e.g., selenols) might represent primary targets in MeHg-induced oxidative stress. Indeed, the inhibition of antioxidant selenoproteins during MeHg poisoning in experimental animals has corroborated this hypothesis. The levels of different reactive species (superoxide anion, hydrogen peroxide and nitric oxide) have been reported to be increased in MeHg-exposed systems, and the mechanisms concerning these increments seem to involve a complex sequence of cascading molecular events, such as mitochondrial dysfunction, excitotoxicity, intracellular calcium dyshomeostasis and decreased antioxidant capacity. This review also discusses potential therapeutic strategies to counteract MeHg-induced toxicity and oxidative stress, emphasizing the use of organic selenocompounds, which generally present higher affinity for MeHg when compared to the classically studied agents.
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Affiliation(s)
- Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Michael Aschner
- Department of Pediatrics and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - João B. T. Rocha
- Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
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Mammalian metallothionein in toxicology, cancer, and cancer chemotherapy. J Biol Inorg Chem 2011; 16:1087-101. [PMID: 21822976 DOI: 10.1007/s00775-011-0823-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 07/20/2011] [Indexed: 12/16/2022]
Abstract
The present paper centers on mammalian metallothionein 1 and 2 in relationship to cell and tissue injury beginning with its reaction with Cd²⁺ and then considering its role in the toxicology and chemotherapy of both metals and non-metal electrophiles and oxidants. Intertwined is a consideration of MTs role in tumor cell Zn²⁺ metabolism. The paper updates and expands on our recent review by Petering et al. (Met Ions Life Sci 5:353-398, 2009).
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