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Martins AC, Ferrer B, Tinkov AA, Caito S, Deza-Ponzio R, Skalny AV, Bowman AB, Aschner M. Association between Heavy Metals, Metalloids and Metabolic Syndrome: New Insights and Approaches. TOXICS 2023; 11:670. [PMID: 37624175 PMCID: PMC10459190 DOI: 10.3390/toxics11080670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 08/26/2023]
Abstract
Metabolic syndrome (MetS) is an important public health issue that affects millions of people around the world and is growing to pandemic-like proportions. This syndrome is defined by the World Health Organization (WHO) as a pathologic condition characterized by abdominal obesity, insulin resistance, hypertension, and hyperlipidemia. Moreover, the etiology of MetS is multifactorial, involving many environmental factors, including toxicant exposures. Several studies have associated MetS with heavy metals exposure, which is the focus of this review. Environmental and/or occupational exposure to heavy metals are a major risk, contributing to the development of chronic diseases. Of particular note, toxic metals such as mercury, lead, and cadmium may contribute to the development of MetS by altering oxidative stress, IL-6 signaling, apoptosis, altered lipoprotein metabolism, fluid shear stress and atherosclerosis, and other mechanisms. In this review, we discuss the known and potential roles of heavy metals in MetS etiology as well as potential targeted pathways that are associated with MetS. Furthermore, we describe how new approaches involving proteomic and transcriptome analysis, as well as bioinformatic tools, may help bring about an understanding of the involvement of heavy metals and metalloids in MetS.
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Affiliation(s)
- Airton C. Martins
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA; (A.C.M.)
| | - Beatriz Ferrer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA; (A.C.M.)
| | - Alexey A. Tinkov
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, 150003 Yaroslavl, Russia; (A.A.T.)
- IM Sechenov First Moscow State Medical University (Sechenov University), 119435 Moscow, Russia
| | - Samuel Caito
- School of Pharmacy, Husson University, Bangor, ME 04401, USA
| | - Romina Deza-Ponzio
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA; (A.C.M.)
| | - Anatoly V. Skalny
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, 150003 Yaroslavl, Russia; (A.A.T.)
- IM Sechenov First Moscow State Medical University (Sechenov University), 119435 Moscow, Russia
| | - Aaron B. Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN 47907-2051, USA;
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA; (A.C.M.)
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Shinoda Y, Akiyama M, Toyama T. Potential Association between Methylmercury Neurotoxicity and Inflammation. Biol Pharm Bull 2023; 46:1162-1168. [PMID: 37661394 DOI: 10.1248/bpb.b23-00075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Methylmercury (MeHg) is the causal substrate of Minamata disease and a major environmental toxicant. MeHg is widely distributed, mainly in the ocean, meaning its bioaccumulation in seafood is a considerable problem for human health. MeHg has been intensively investigated and is known to induce inflammatory responses and neurodegeneration. However, the relationship between MeHg-induced inflammatory responses and neurodegeneration is not understood. In the present review, we first describe recent findings showing an association between inflammatory responses and certain MeHg-unrelated neurological diseases caused by neurodegeneration. In addition, cell-specific MeHg-induced inflammatory responses are summarized for the central nervous system including those of microglia, astrocytes, and neurons. We also describe MeHg-induced inflammatory responses in peripheral cells and tissue, such as macrophages and blood. These findings provide a concept of the relationship between MeHg-induced inflammatory responses and neurodegeneration, as well as direction for future research of MeHg-induced neurotoxicity.
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Affiliation(s)
- Yo Shinoda
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Masahiro Akiyama
- Research Center for Drug Discovery, Faculty of Pharmacy and Graduate School of Pharmaceutical Sciences, Keio University
| | - Takashi Toyama
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University
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Duc HN, Oh H, Kim MS. The Effect of Mixture of Heavy Metals on Obesity in Individuals ≥50 Years of Age. Biol Trace Elem Res 2022; 200:3554-3571. [PMID: 34686995 DOI: 10.1007/s12011-021-02972-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/13/2021] [Indexed: 10/20/2022]
Abstract
Little is known about the association between a mixture of heavy metals and obesity among individuals ≥50 years of age with comorbidities. Thus, we identified the associations of serum cadmium (Cd), lead (Pb), and mercury (Hg) with obesity using linear regression models; weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR) were conducted as secondary analyses. Of the 6434 subjects included in the analysis, 13.8% had obesity and 44.6% had abdominal obesity. In the logistic regression model, serum Hg was associated with obesity and abdominal obesity, and significant trends were observed for these heavy metal tertiles (p < 0.001). Serum Hg levels were also associated with body mass index (BMI) and waist circumference (WC). The WQS index was significantly associated with both obesity (OR = 1.43, 95% CI: 1.40-1.46) and abdominal obesity (β = 1.51, 95% CI: 1.48-1.54). The qgcomp index also found a significant association between heavy metals and both obesity (OR = 1.35, 95% CI: 1.12-1.63) and abdominal obesity (OR = 1.34, 95% CI: 1.12-1.60). Serum Hg was the most heavily weighed heavy metal in these models. In BKMR analysis, the overall effect of the mixture was significantly associated with obesity, BMI, and WC. Serum Hg showed positive trends and was observed as the most important factor associated with obesity, BMI, and WC. Our findings were largely robust to secondary analyses that used three novel mixture modeling approaches: WQS, qpcomp, and BKMR. Given increasing exposure to heavy metals, well-characterized cohorts of individuals aged ≥50 years are required to determine the mixed effects of heavy metals on obesity and related diseases.
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Affiliation(s)
- Hai Nguyen Duc
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, Jeonnam, Republic of Korea
| | - Hojin Oh
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, Jeonnam, Republic of Korea
| | - Min-Sun Kim
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, Jeonnam, Republic of Korea.
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Methylmercury-Induced Metabolic Alterations in Caenorhabditis elegans Are Diet-Dependent. TOXICS 2021; 9:toxics9110287. [PMID: 34822679 PMCID: PMC8619518 DOI: 10.3390/toxics9110287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/22/2021] [Accepted: 10/29/2021] [Indexed: 01/12/2023]
Abstract
Methylmercury (MeHg) is a well-known neurotoxicant; however, its role in metabolic diseases has been gaining wider attention. Chronic exposure to MeHg in human populations shows an association with diabetes mellitus and metabolic syndrome (MS). As the incidences of both obesity and MS are on the rise globally, it is important to understand the potential role of MeHg in the development of the disease. There is a dearth of information on dietary interactions between MeHg and lipids, which play an important role in developing MS. We have previously shown that MeHg increases food seeking behaviors, lipid levels, fat storage, and pro-adipogenic gene expression in C. elegans fed the standard OP50 Escherichia coli diet. However, we hypothesized that these metabolic changes could be prevented if the worms were fed a bacterial diet lower in lipid content. We tested whether C. elegans developed metabolic alterations in response to MeHg if they were fed two alternative E. coli strains (HT115 and HB101) that are known absorb significantly less lipids from their media. Additionally, to explore the effect of a high-lipid and high-cholesterol diet on MeHg-induced metabolic dysfunction, we supplemented the OP50 strain with twice the standard concentration of cholesterol in the nematode growth media. Wild-type worms fed either the HB101 or HT115 diet were more resistant to MeHg than the worms fed the OP50 diet, showing a significant right-hand shift in the dose–response survival curve. Worms fed the OP50 diet supplemented with cholesterol were more sensitive to MeHg, showing a significant left-hand shift in the dose–response survival curve. Changes in sensitivity to MeHg by differential diet were not due to altered MeHg intake in the worms as measured by inductively coupled mass spectrometry. Worms fed the low-fat diets showed protection from MeHg-induced metabolic changes, including decreased food consumption, lower triglyceride content, and lower fat storage than the worms fed either of the higher-fat diets. Oxidative stress is a common characteristic of both MeHg exposure and high-fat diets. Worms fed either OP50 or OP50 supplemented with cholesterol and treated with MeHg had significantly higher levels of reactive oxygen species, carbonylated proteins, and loss of glutathione than the worms fed the HT115 or HB101 low-lipid diets. Taken together, our data suggest a synergistic effect of MeHg and dietary lipid levels on MeHg toxicity and fat metabolism in C. elegans, which may affect the ability of MeHg to cause metabolic dysfunction.
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Roque CR, Sampaio LR, Ito MN, Pinto DV, Caminha JSR, Nunes PIG, Raposo RS, Santos FA, Windmöller CC, Crespo-Lopez ME, Alvarez-Leite JI, Oriá RB, Pinheiro RF. Methylmercury chronic exposure affects the expression of DNA single-strand break repair genes, induces oxidative stress, and chromosomal abnormalities in young dyslipidemic APOE knockout mice. Toxicology 2021; 464:152992. [PMID: 34670124 DOI: 10.1016/j.tox.2021.152992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 10/01/2021] [Accepted: 10/12/2021] [Indexed: 12/31/2022]
Abstract
Mercury (Hg) is one of the most toxic environmental pollutants, especially when methylated, forming methylmercury (MeHg). MeHg affects DNA repair, increases oxidative stress, and predisposes to cancer. MeHg neurotoxicity is well-known, but recently MeHg-associated cardiovascular effects were recognized. This study evaluated circulating lipids, oxidative stress, and genotoxicity after MeHg-chronic exposure (20 mg/L in drinking water) in C57BL/6J wild-type and APOE knockout (ko) mice, the latter, being spontaneously dyslipidemic. Experimental mice were assigned to four groups: non-intoxicated and MeHg-intoxicated wild-type mice and non-intoxicated and MeHg-intoxicated APOE ko mice. Plasma levels of triglycerides, total cholesterol (TC), HDL, and LDL were analyzed. Liver lipid peroxidation and splenic gene expression of xeroderma pigmentosum complementation groups A, C, D, and G (XPA, XPC, XPD, and XPG), X-ray repair cross-complementing protein 1 (XRCC1), and telomerase reverse transcriptase (TERT) were measured. Fur Hg levels confirmed chronic MeHg intoxication. MeHg exposure raises TC levels both in wild-type and APOE ko mice. HDL and LDL-cholesterol levels were increased only in the MeHg-challenged APOE ko mice. MeHg increased liver lipid peroxidation, regardless of the genetic background. Unintoxicated APOE ko mice showed higher expression of TERT than all other groups. APOE deficiency increases XPA expression, regardless of MeHg intoxication. Furthermore, MeHg-intoxicated mice had more cytogenetic abnormalities, effect which was independent of APOE deficiency. More studies are needed to dissect the interactions between circulating lipids, MeHg intoxication, and DNA-repair pathways even at young age, interactions that likely play critical roles in cell senescence and the risk for chronic disorders later in life.
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Affiliation(s)
- Cássia R Roque
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology and Institute of Biomedicine, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Letícia R Sampaio
- Cancer Cytogenomics Laboratory, Drug Research, and Development Center, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Mayumi N Ito
- Cancer Cytogenomics Laboratory, Drug Research, and Development Center, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Daniel V Pinto
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology and Institute of Biomedicine, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Juan S R Caminha
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology and Institute of Biomedicine, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Paulo I G Nunes
- Natural Products Laboratory, Biomedicine Center, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Ramon S Raposo
- Experimental Biology core, Health Sciences, University of Fortaleza, Fortaleza, CE, Brazil
| | - Flávia A Santos
- Natural Products Laboratory, Biomedicine Center, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Cláudia C Windmöller
- Laboratory of Atherosclerosis and Nutritional Biochemistry, Department of Biochemistry and Immunology, ICB, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Maria Elena Crespo-Lopez
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Jacqueline I Alvarez-Leite
- Laboratory of Atherosclerosis and Nutritional Biochemistry, Department of Biochemistry and Immunology, ICB, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Reinaldo B Oriá
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology and Institute of Biomedicine, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil.
| | - Ronald F Pinheiro
- Cancer Cytogenomics Laboratory, Drug Research, and Development Center, Federal University of Ceara, Fortaleza, CE, Brazil
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Yang YJ, Yang EJ, Park K, Oh S, Kim T, Hong YP. Association between Blood Mercury Levels and Non-Alcoholic Fatty Liver Disease in Non-Obese Populations: The Korean National Environmental Health Survey (KoNEHS) 2012-2014. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18126412. [PMID: 34199270 PMCID: PMC8296250 DOI: 10.3390/ijerph18126412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/18/2021] [Accepted: 05/23/2021] [Indexed: 12/04/2022]
Abstract
Mercury is widely distributed in the environment, and a plausible association between mercury exposure and hepatic damage has been reported. Non-alcoholic fatty liver disease (NAFLD), which comprises a spectrum of liver diseases, has recently been recognized in non-obese subjects. However, there have been no studies on the relationship between internal mercury levels and NAFLD in non-obese individuals. Therefore, we investigated the association between blood mercury levels and NAFLD in non-obese subjects. Cross-sectional data (n = 5919) were obtained from the Korean National Environmental Health Survey (2012–2014). NAFLD was defined using the hepatic steatosis index (HSI). Blood mercury levels were log-transformed and divided into quartiles based on a weighted sample distribution. The association between blood mercury levels and NAFLD was analyzed using a multivariate logistic analysis after body mass index stratification. The geometric mean of blood mercury in the overweight group was significantly higher than that of the non-obese group (p < 0.001). The weighted frequencies of patients with NAFLD based on the HSI were 3.0–7.2% for the non-obese subjects and 52.3–63.2% for the overweight subjects. In the multivariate analysis, blood mercury levels were positively associated with NAFLD for both the overweight and non-obese groups (all p for trend < 0.001). Increased blood mercury levels are closely associated with NAFLD. In particular, mercury could be a risk factor for NAFLD in the non-obese population.
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Affiliation(s)
- Yun-Jung Yang
- Institute of Biomedical Science, Catholic Kwandong University International St. Mary’s Hospital, Incheon 22711, Korea;
| | - Eun-Jung Yang
- Department of Plastic and Reconstructive Surgery, Yonsei University College of Medicine, Seoul 03722, Korea;
| | - Kyongjin Park
- College of Medicine, Catholic Kwandong University, Gangneung-si 25601, Korea; (K.P.); (S.O.); (T.K.)
| | - Subin Oh
- College of Medicine, Catholic Kwandong University, Gangneung-si 25601, Korea; (K.P.); (S.O.); (T.K.)
| | - Taehyen Kim
- College of Medicine, Catholic Kwandong University, Gangneung-si 25601, Korea; (K.P.); (S.O.); (T.K.)
| | - Yeon-Pyo Hong
- Department of Preventive Medicine, College of Medicine, Chung-Ang University, Seoul 06974, Korea
- Correspondence: ; Tel.: +82-2-820-5667
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Caito SW, Newell-Caito J, Martell M, Crawford N, Aschner M. Methylmercury Induces Metabolic Alterations in Caenorhabditis elegans: Role for C/EBP Transcription Factor. Toxicol Sci 2021; 174:112-123. [PMID: 31851340 DOI: 10.1093/toxsci/kfz244] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Methylmercury (MeHg) is a well-known neurotoxicant; however, its role in metabolic diseases has been gaining wider attention. We have previously shown that MeHg causes metabolic alterations in Caenorhabditis elegans, leading to decreased nicotinamide adenine dinucleotide cofactor, mitochondrial dysfunction, and oxidative stress. We were, therefore, interested in whether MeHg also affects nutrient metabolism, particularly lipid homeostasis, which may contribute to the development of metabolic conditions such as obesity or metabolic syndrome (MS). RNA from wild-type worms exposed to MeHg was collected immediately after treatment and used for gene expression analysis by DNA microarray. MeHg differentially regulated 215 genes, 17 genes involved in lipid homeostasis, and 12 genes involved in carbohydrate homeostasis. Of particular interest was cebp-1, the worm ortholog to human C/EBP, a pro-adipogenic transcription factor implicated in MS. MeHg increased the expression of cebp-1 as well as pro-adipogenic transcription factors sbp-1 and nhr-49, triglyceride synthesis enzyme acl-6, and lipid transport proteins vit-2 and vit-6. Concurrent with the altered gene expression, MeHg increased triglyceride levels, lipid storage, and feeding behaviors. Worms expressing mutant cebp-1 were protected from MeHg-induced alterations in lipid content, feeding behaviors, and gene expression, highlighting the importance of this transcription factor in the worm's response to MeHg. Taken together, our data demonstrate that MeHg induces biochemical, metabolic, and behavioral changes in C. elegans that can lead to metabolic dysfunction.
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Affiliation(s)
- Samuel W Caito
- Department of Basic Pharmaceutical Sciences, Husson University School of Pharmacy, Bangor, Maine
| | | | - Megan Martell
- Department of Basic Pharmaceutical Sciences, Husson University School of Pharmacy, Bangor, Maine
| | - Nicole Crawford
- Department of Basic Pharmaceutical Sciences, Husson University School of Pharmacy, Bangor, Maine
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
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DHA and Its Metabolites Have a Protective Role against Methylmercury-Induced Neurotoxicity in Mouse Primary Neuron and SH-SY5Y Cells. Int J Mol Sci 2021; 22:ijms22063213. [PMID: 33809931 PMCID: PMC8004243 DOI: 10.3390/ijms22063213] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023] Open
Abstract
The consumption of fish now involves a risk of methylmercury (MeHg) exposure but also provides the benefit of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) such as docosahexaenoic acid (DHA). Some epidemiological studies have suggested that the intake of DHA can alleviate the neurotoxicity of MeHg, but the underlying mechanism is not known. Herein, we observed that pretreatment with 0.1–1 µM DHA suppressed MeHg-induced cytotoxicity in human neuroblastoma (SH-SY5Y) cells and mouse primary neuronal cells. These effects of DHA were canceled in the presence of the retinoid X receptor (RXR) antagonist UVI3003. An RXR agonist, bexarotene, suppressed the cytotoxicity of MeHg. DHA also suppressed the MeHg-induced production of reactive oxygen species (ROS) via an induction of antioxidant genes (catalase and SOD1). Pretreatment with DHA did not change the incorporation of MeHg. We showed previously that in the brain, the intake of DHA increased the level of 19,20-DHDP, which is the metabolite produced by cytochrome P450 and soluble epoxide hydrolase from DHA. In the present study, we observed that 19,20-DHDP also suppressed neurotoxicity from MeHg. These results indicate that DHA and its metabolites have a protective role in MeHg-induced neurotoxicity.
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Ferrer B, Prince LM, Tinkov AA, Santamaria A, Farina M, Rocha JB, Bowman AB, Aschner M. Chronic exposure to methylmercury enhances the anorexigenic effects of leptin in C57BL/6J male mice. Food Chem Toxicol 2020; 147:111924. [PMID: 33338554 DOI: 10.1016/j.fct.2020.111924] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 02/06/2023]
Abstract
Several studies have demonstrated that heavy metals disrupt energy homeostasis. Leptin inhibits food intake and decreases body weight through activation of its receptor in the hypothalamus. The impact of heavy metals on leptin signaling in the hypothalamus is unclear. Here, we show that the environmental pollutant, methylmercury (MeHg), favors an anorexigenic profile in wild-type males. C57BL/6J mice were exposed to MeHg via drinking water (5 ppm) up to 30 days. Our data shows that MeHg exposure was associated with changes in leptin induced activation of Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in the hypothalamus. In males, the activation of JAK2/STAT3 signaling pathway was sustained by an increase in SOCS3 protein levels. In females, MeHg-activated STAT3 was inhibited by a concomitant increase in PTP1B. Taken together, our data suggest that MeHg enhanced leptin effects in males, favoring an anorexigenic profile in males, which notably, have been shown to be more sensitive to the neurological effects of this organometal than females. A better understanding of MeHg-induced molecular mechanism alterations in the hypothalamus advances the understanding of its neurotoxicity and provides molecular sites for novel therapies.
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Affiliation(s)
- Beatriz Ferrer
- Department of Molecular Pharmacology, Neuroscience, and Pediatrics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, 10461, Bronx, NY, USA.
| | - Lisa M Prince
- School of Health Sciences, Purdue University, West Lafayette, IN, United States.
| | - Alexey A Tinkov
- Yaroslavl State University, Yaroslavl, Russia; IM Sechenov First Moscow State Medical University, Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia; Federal Research Centre of Biological Systems and Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia.
| | - Abel Santamaria
- Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neurología y Neurocirugía, 14269, Mexico City, Mexico.
| | - Marcelo Farina
- Department of Biochemistry, Biological Sciences Center, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
| | - João Batista Rocha
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
| | - Aaron B Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN, United States.
| | - Michael Aschner
- Department of Molecular Pharmacology, Neuroscience, and Pediatrics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, 10461, Bronx, NY, USA; IM Sechenov First Moscow State Medical University, Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia.
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10
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Ferrer B, Prince LM, Tinkov AA, Santamaria A, Bowman AB, Aschner M. Chronic exposure to methylmercury disrupts ghrelin actions in C57BL/6J mice. Food Chem Toxicol 2020; 147:111918. [PMID: 33301842 DOI: 10.1016/j.fct.2020.111918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 01/06/2023]
Abstract
Methylmercury (MeHg) is a neurotoxic pollutant widely present in the environment. Initial symptoms of MeHg may include loss of body weight. However, the mechanisms by which MeHg induces body weight changes have yet to be fully elucidated. Body weight is regulated by multiple mechanisms. Whereas multiple peripheral peptides lead to food intake cessation, ghrelin is the only recognized peripheral hormone that stimulates food intake. It exerts its action on Neuropeptide Y/Agouti-related peptide neurons in the hypothalamus. To test if MeHg affects ghrelin signaling C57BL/6J mice (males and females) were exposed to 5 ppm MeHg via drinking water during a month. On days 15 and 30 of MeHg exposure ghrelin was administered intraperitoneally and changes in body weight and food intake were recorded. In addition, changes in ghrelin-induced signaling pathways in hypothalamus were also analyzed. Here, we show that in males, MeHg enhanced ghrelin-induced body weight gain by activating the AMP-activated Kinase (AMPK)/Uncoupled protein 2 (UCP2) signaling pathway. In contrast, in females, MeHg inhibited ghrelin-induced mTOR signaling activation and decreased Npy mRNA expression, thus mitigating the ghrelin-induced weight gain. Combined, our novel results demonstrate, for the first time, that MeHg disrupts the physiological functions of ghrelin differently in males and females.
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Affiliation(s)
- Beatriz Ferrer
- Department of Molecular Pharmacology, Neuroscience, and Pediatrics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, 10461, Bronx, NY, USA.
| | - Lisa M Prince
- School of Health Sciences, Purdue University, West Lafayette, IN, USA.
| | - Alexey A Tinkov
- IM Sechenov First Moscow State Medical University, Moscow, Russia; Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia; Yaroslavl State University, Yaroslavl, Russia; Federal Research Centre of Biological Systems and Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia.
| | - Abel Santamaria
- Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neurología y Neurocirugía, 14269, Mexico City, Mexico.
| | - Aaron B Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN, USA.
| | - Michael Aschner
- Department of Molecular Pharmacology, Neuroscience, and Pediatrics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, 10461, Bronx, NY, USA; IM Sechenov First Moscow State Medical University, Moscow, Russia; Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia.
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11
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Kim B, Shah S, Park HS, Hong YC, Ha M, Kim Y, Kim BN, Kim Y, Ha EH. Adverse effects of prenatal mercury exposure on neurodevelopment during the first 3 years of life modified by early growth velocity and prenatal maternal folate level. ENVIRONMENTAL RESEARCH 2020; 191:109909. [PMID: 32871452 DOI: 10.1016/j.envres.2020.109909] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 05/30/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND AIMS Previous studies have suggested that mercury exposure and folate levels during pregnancy may influence early childhood neurodevelopment. Rapid catch-up growth in children is associated with an increased risk of pathological nervous system development. We evaluated whether the association between prenatal folate and mercury-related neuropsychological dysfunction was modified by growth velocity during childhood. METHODS The Mothers and Children's Environmental Health (MOCEH) birth cohort study began in 2006 and by 2010, 1751 women had been enrolled before the second trimester of their pregnancy along with their partners. Participants visited the research center at birth and 6, 12, 24, and 36 months. We measured mercury levels in maternal and cord blood and folate in maternal serum. Questionnaires to evaluate the environment and health of their child were administered and anthropometric factors including body weight and height were measured. Certified investigators used the Bayley test to measure neurobehavioral outcomes. We calculated postnatal growth change as the change in infant weight for-age z-score between birth and 3 years. Multiple linear regression and mixed models were used to examine the association between mercury exposure and children's neurodevelopment as well as the modifying effects of folate and growth velocity. RESULTS A total of 30.6% of children experienced rapid growth during the first 3 years of life. Median values of mercury in the low folate group were significantly higher in rapid growers (3.41 μg/L in maternal blood and 5.63 μg/L in cord blood) than in average/slow growers (3.05 μg/L in maternal blood and 5.19 μg/L in cord blood). Rapid growers were also significantly associated with decreased psychomotor development scores during the first 3 years of life and with having mothers who had low prenatal folate levels, even after adjusting for potential confounders. CONCLUSION Prenatal mercury exposure adversely affects infant neurodevelopment and is associated with rapid growth during the first 3 years of life. This effect was limited to children whose mothers had low prenatal folate levels, suggesting a protective effect of folate against developmental neurotoxicity due to mercury exposure and rapid catch-up growth.
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Affiliation(s)
- Byungmi Kim
- National Cancer Control Institute, National Cancer Center, Goyang, Republic of Korea
| | - Surabhi Shah
- Department of Occupational and Environmental Medicine, College of Medicine, Ewha Medical Research Center, Ewha Womans University, Seoul, Republic of Korea
| | - Hye-Sook Park
- Department of Preventive Medicine, College of Medicine, Ewha Medical Research Center, Ewha Womans University, Seoul, Republic of Korea
| | - Yun-Chul Hong
- Department of Preventive Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Mina Ha
- Department of Preventive Medicine, College of Medicine, Dankook University, Cheonan, Republic of Korea
| | - Yangho Kim
- Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | - Boong-Nnyun Kim
- Division of Child & Adolescent Psychiatry, Department of Psychiatry and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yeni Kim
- Department of Child and Adolescent Psychiatry, National Center for Mental Health, Seoul, Republic of Korea
| | - Eun-Hee Ha
- Department of Occupational and Environmental Medicine, College of Medicine, Ewha Medical Research Center, Ewha Womans University, Seoul, Republic of Korea.
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12
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Lacerda Leocádio PC, Dias RP, Pinto DV, Reis JM, Rodrigues Nascimento JC, Anne de Castro Brito G, Valença JT, Foureaux G, Ferreira AJ, Windmöller CC, Crespo-Lopez ME, Santos FA, Oriá RB, Alvarez-Leite JI. Pollutants and nutrition: Are methylmercury effects on blood pressure and lipoprotein profile comparable to high-fat diet in mice? ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 204:111036. [PMID: 32784013 DOI: 10.1016/j.ecoenv.2020.111036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 06/11/2023]
Abstract
Human exposure to methylmercury (MeHg) due to contaminated fish intake as part of a high-fat (HFD), high-carbohydrate diets is a reality today for many populations. HFD is associated with hypertension and hyperlipidemia, primary cardiovascular disease (CVD) risk factors. Some studies suggest that MeHg induces those risk factors. We evaluated the effect of MeHg exposure in mice fed with HFD or control diet for eight weeks. In the last experimental 15 days, the half group received a MeHg solution (20 mg/L) replacing water. Blood pressure (BP), heart rate, lipoprotein concentrations, and paraoxonase activity were evaluated. Liver cholesterol, triacylglycerol, and IBA-1+ cells, as well as transcriptional levels of genes related to lipid metabolism and inflammatory response, were also assessed. HFD and both MeHg groups presented increased BP and total cholesterol (TC). In the liver, HFD but not MeHg was related to an increase in TC. Also, MeHg intoxication reduced paraoxonase activity regardless of diet. MeHg intoxication and HFD increased steatosis and the number of IBA-1+ cells and modified some gene transcripts associated with lipid metabolism. In conclusion, we demonstrated that MeHg effects on CVD risk factors resemble those caused by HFD.
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13
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Yamamoto M, Yanagisawa R, Sakai A, Mogi M, Shuto S, Shudo M, Kashiwagi H, Kudo M, Nakamura M, Sakamoto M. Toxicokinetics of methylmercury in diabetic KK-Ay mice and C57BL/6 mice. J Appl Toxicol 2020; 41:928-940. [PMID: 33015845 DOI: 10.1002/jat.4078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/19/2020] [Accepted: 09/05/2020] [Indexed: 12/19/2022]
Abstract
We compared the toxicokinetics of methylmercury (MeHg) in KK-Ay type 2 diabetic mice and C57BL/6J mice to evaluate how metabolic changes associated with diabetes affect MeHg toxicokinetics. A single dose of MeHg (0.2, 1, or 5 mg mercury/kg) was administered orally to 12-week-old KK-Ay and C57BL/6J male mice. Total mercury concentrations in plasma, blood cells, whole blood, and tissues (brain, kidneys, liver, and pancreas) were measured after 4, 7, 11, and 14 days. The volume of distribution/bioavailability and the elimination rate constant per day were higher in KK-Ay mice, while the terminal elimination half-life was lower in almost all samples of KK-Ay mice. The area under the curve was lower in all blood and almost all tissue samples from KK-Ay mice. Total clearance/bioavailability was lower in all blood and tissue samples of KK-Ay mice at all MeHg doses. These results indicate that MeHg is more rapidly absorbed by, and eliminated from, the blood cells, brain, liver, kidney, and pancreas of KK-Ay mice under the experimental conditions. Different patterns of tissue-to-plasma and tissue-to-whole blood partition coefficients suggest that notable differences in MeHg transfer between plasma and blood cells affect its distribution in tissues of the two mouse strains. These findings are useful to understand the selective distribution of MeHg to target organs and the sensitivity to MeHg in pathological states.
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Affiliation(s)
- Megumi Yamamoto
- Department of Environment and Public Health, National Institute for Minamata Disease, Minamata, Japan
| | - Rie Yanagisawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan
| | | | - Masaki Mogi
- Department of Pharmacology, Ehime University Graduate School of Medicine, Toon, Japan
| | - Satoshi Shuto
- Department of Molecular Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Masachika Shudo
- Advanced Research Support Center, Ehime University, Matsuyama, Japan
| | - Hazuki Kashiwagi
- Department of Environment and Public Health, National Institute for Minamata Disease, Minamata, Japan
| | - Megumi Kudo
- Department of Environment and Public Health, National Institute for Minamata Disease, Minamata, Japan
| | - Masaaki Nakamura
- Department of Clinical Medicine, National Institute for Minamata Disease, Minamata, Japan
| | - Mineshi Sakamoto
- Department of Environment and Public Health, National Institute for Minamata Disease, Minamata, Japan
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14
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Muniroh M, Gumay AR, Indraswari DA, Bahtiar Y, Hardian H, Bakri S, Maharani N, Karlowee V, Koriyama C, Yamamoto M. Activation of MIP-2 and MCP-5 Expression in Methylmercury-Exposed Mice and Their Suppression by N-Acetyl-L-Cysteine. Neurotox Res 2020; 37:827-834. [PMID: 32040762 DOI: 10.1007/s12640-020-00174-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 01/15/2020] [Accepted: 02/02/2020] [Indexed: 01/11/2023]
Abstract
Methylmercury (MeHg) is a well-known neurotoxin of the central nervous system (CNS). Neuroinflammation is one of the main pathways of MeHg-induced CNS impairment. This study aims to investigate the expressions of IL-6, MIP-2, and MCP-5, as biomarkers in relation with MeHg-induced CNS impairment and N-acetyl-L-cysteine (NAC) treatment in mice, as well as histopathological changes of brain tissue and clinical symptom such as ataxia. Twenty male Balb/c mice, aged 8-9 weeks, were divided into 4 groups and treated with saline (control), NAC [150 mg/kg body weight (BW) day], MeHg (4 mg Hg/kg BW), or a combination of MeHg and NAC for 17 days. MeHg induced the expression of IL-6, MIP-2, and MCP-5 in the serum, with median values (those in controls) of 55.06 (9.44), 15.94 (9.30), and 458.91 (239.91) mg/dl, respectively, and a statistical significance was observed only in IL-6 expression (p < 0.05). MIP-2 and MCP-5 expressions tended to increase in the cerebrum of MeHg-treated group compared with controls; however, the difference was not statistically significant. MeHg treatment also increased IL-6 expression in the cerebellum (7.73 and 4.81 mg/dl in MeHg-treated group and controls, respectively), with a marginal significance. NAC significantly suppressed MeHg-induced IL-6 and MIP-2 expressions in the serum (p < 0.05 for both), and slightly reduced MCP-5 expression in the cerebrum. Ataxia was observed in all MeHg-treated mice after 9-day exposure as well as the decrease of intact Purkinje cells in brain tissue (p < 0.05). These findings suggest that MeHg induced neurotoxicity by elevating the expression of IL-6, MIP-2, and MCP-5 and causing ataxia symptoms, and NAC reduced MeHg-mediated effects on the CNS.
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Affiliation(s)
- Muflihatul Muniroh
- Department of Physiology, Faculty of Medicine Diponegoro University, Tembalang Semarang, 50275, Indonesia.
| | - Ainun Rahmasari Gumay
- Department of Physiology, Faculty of Medicine Diponegoro University, Tembalang Semarang, 50275, Indonesia
| | - Darmawati Ayu Indraswari
- Department of Physiology, Faculty of Medicine Diponegoro University, Tembalang Semarang, 50275, Indonesia
| | - Yuriz Bahtiar
- Department of Physiology, Faculty of Medicine Diponegoro University, Tembalang Semarang, 50275, Indonesia
| | - Hardian Hardian
- Department of Physiology, Faculty of Medicine Diponegoro University, Tembalang Semarang, 50275, Indonesia
| | - Saekhol Bakri
- Department of Public Health, Faculty of Medicine Diponegoro University, Semarang, 50275, Indonesia
| | - Nani Maharani
- Department of Pharmacology and Therapy, Faculty of Medicine Diponegoro University, Semarang, 50275, Indonesia
| | - Vega Karlowee
- Department of Anatomical Pathology, Faculty of Medicine Diponegoro University, Semarang, 50275, Indonesia
| | - Chihaya Koriyama
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Health Sciences, Kagoshima, 890-8520, Japan
| | - Megumi Yamamoto
- Department of Environment and Public Health, National Institute for Minamata Disease, Kumamoto, 867-0008, Japan
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David J, Muniroh M, Nandakumar A, Tsuji M, Koriyama C, Yamamoto M. Inorganic mercury-induced MIP-2 expression is suppressed by N-acetyl-L-cysteine in RAW264.7 macrophages. Biomed Rep 2020; 12:39-45. [PMID: 31929872 PMCID: PMC6951253 DOI: 10.3892/br.2019.1263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 10/02/2019] [Indexed: 11/06/2022] Open
Abstract
Macrophages play an important role in neurotoxicity caused by methylmercury exposure through inflammatory responses. Methylmercury is known to demethylate to inorganic mercury in the brain, and macrophages are likely to be involved in this process. However, the inflammatory responses of macrophages against exposure to inorganic mercury are unclear. In the present study, inflammatory cytokine expression profiles were examined in the presence of non-toxic doses of inorganic mercury (Hg2+) using RAW264.7 macrophages, focusing on the expression of C-X-C motif chemokine 2 (MIP-2)/platelet-derived growth factor-inducible protein KC (KC) and C-C motif chemokine 12 (MCP-5). Furthermore, the suppressive effect of N-acetyl-L-cysteine (NAC) on inorganic mercury-induced MIP-2 expression was also examined. Inorganic mercury-induced mRNA expression was measured using reverse transcription-quantitative PCR. The mRNA expression of MIP-2 and MCP-5 was significantly upregulated by exposure to 20 µM Hg2+ (non-toxic levels), but not that of KC. The suppressive effect of NAC on these cytokine expression levels was examined by its addition to the culture medium together with Hg2+ (co-treatment), and pre- and post-treatments in which the cells were treated with NAC before and after Hg2+ exposure, respectively. Hg2+-upregulated MIP-2 expression was suppressed by NAC regardless of the time sequence of the treatment, suggesting that the suppressive role of NAC in Hg2+-induced inflammation manifests as a possible chelator and antioxidant/reactive oxygen species scavenger.
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Affiliation(s)
- Juliet David
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Muflihatul Muniroh
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan.,Department of Physiology, Faculty of Medicine, Diponegoro University, Semarang, Central Java 50725, Indonesia
| | - Athira Nandakumar
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Mayumi Tsuji
- Department of Environmental Health, University of Occupational and Environmental Health, Kitakyusyu, Fukuoka 807-8555, Japan
| | - Chihaya Koriyama
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Megumi Yamamoto
- Department of Environment and Public Health, National Institute for Minamata Disease, Minamata, Kumamoto 867-0008, Japan
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16
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Shinoda Y, Ehara S, Tatsumi S, Yoshida E, Takahashi T, Eto K, Kaji T, Fujiwara Y. Methylmercury-induced neural degeneration in rat dorsal root ganglion is associated with the accumulation of microglia/macrophages and the proliferation of Schwann cells. J Toxicol Sci 2019; 44:191-199. [PMID: 30842371 DOI: 10.2131/jts.44.191] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Exposure to organic mercury, especially methylmercury (MeHg), causes Minamata disease, a severe chronic neurological disorder. Minamata disease predominantly affects the central nervous system, and therefore, studies on the mechanisms of MeHg neurotoxicity have focused primarily on the brain. Although the peripheral nervous system is also affected by the organometallic compound and shows signs of neural degeneration, the mechanisms of peripheral MeHg neurotoxicity remain unclear. In the present study, we performed quantitative immunohistochemical analyses of the dorsal root ganglion (DRG) and associated sensory and motor fibers to clarify the mechanisms of MeHg-induced peripheral neurotoxicity in Wistar rats. Methylmercury chloride (6.7 mg/kg/day) was orally administrated for 5 days, followed by 2 days without administration, and this cycle was repeated once again. Seven and 14 days after the beginning of MeHg exposure, rats were anesthetized, and their DRGs and sensory and motor nerve fibers were removed and processed for immunohistochemical analyses. The frozen sections were immunostained for neuronal, Schwann cell, microglial and macrophage markers. DRG sensory neuron somata and axons showed significant degeneration on day 14. At the same time, an accumulation of microglia and the infiltration of macrophages were observed in the DRGs and sensory nerve fibers. In addition, MeHg caused significant Schwann cell proliferation in the sensory nerve fibers. In comparison, there was no noticeable change in the motor fibers. Our findings suggest that in the peripheral nervous system, MeHg toxicity is associated with neurodegenerative changes to DRG sensory neurons and the induction of a neuroprotective and/or enhancement of neurodegenerative host response.
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Affiliation(s)
- Yo Shinoda
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Shunsuke Ehara
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Satoshi Tatsumi
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Eiko Yoshida
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Tsutomu Takahashi
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Komyo Eto
- Health and Nursing Facilities for the Aged, Jushindai, Shinwakai
| | - Toshiyuki Kaji
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Yasuyuki Fujiwara
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
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17
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Rizzetti DA, Corrales P, Piagette JT, Uranga-Ocio JA, Medina-Gomez G, Peçanha FM, Vassallo DV, Miguel M, Wiggers GA. Chronic mercury at low doses impairs white adipose tissue plasticity. Toxicology 2019; 418:41-50. [PMID: 30807803 DOI: 10.1016/j.tox.2019.02.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 01/31/2019] [Accepted: 02/23/2019] [Indexed: 02/07/2023]
Abstract
INTRODUCTION The toxic effects of mercury (Hg) are involved in homeostasis of energy systems such as lipid and glucose metabolism, and white adipose tissue dysfunction is considered as a central mechanism leading to metabolic disorders. OBJECTIVE The aim of this study was to determine the effects of chronic inorganic Hg exposure at low doses on the lipid and glycemic metabolism. METHODS Male Wistar rats were divided into two groups and treated for 60 days with: saline solution, i.m. (Untreated) and mercury chloride, i.m. - 1st dose 4.6 μg/kg, subsequent doses 0.07 μg/kg/day - (Mercury). Histological analyses, Hg levels measurement and GRP78, CHOP, PPARα, PPARγ, leptin, adiponectin and CD11 mRNA expressions were performed in epididymal white adipose tissue (eWAT). Glucose, triglycerides, total cholesterol and insulin plasma levels were also measured. RESULTS Hg exposure reduced the absolute and relative eWAT weights, adipocyte size, plasma insulin levels, glucose tolerance, antioxidant defenses and increased plasma glucose and triglyceride levels. In addition, CHOP, GRP78, PPARα, PPARγ, leptin and adiponectin mRNA expressions were increased in Hg-treated animals. No differences in Hg concentration were found in eWAT between the untreated and Hg groups. These results suggest that the reduction in adipocyte size is related to the impaired antioxidant defenses, endoplasmic reticulum (ER) stress, the disrupted PPARs and adipokines mRNA expression induced by the metal in eWAT. These disturbances possibly induced a decrease in circulating insulin levels, an imbalance between lipolysis and lipogenesis mechanisms in eWAT, with an increase in fatty acids mobilization, a reduction in glucose uptake and an activation of pro-apoptotic pathways, leading to hyperglycemia and hyperlipidemia. CONCLUSIONS Hg is a powerful environmental WAT disruptor that influences signaling events and impairs metabolic activity and hormonal balance of adipocytes.
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Affiliation(s)
- Danize Aparecida Rizzetti
- Cardiovascular Physiology Laboratory, Universidade Federal do Pampa, BR 472, Km 592, Uruguaiana, Rio Grande do Sul, Brazil; Polytechnic School, Federal University of Santa Maria, Av. Roraima, n° 1000, Santa Maria, Rio Grande do Sul, Brazil.
| | - Patricia Corrales
- Department of Basic Health Sciences, Universidad Rey Juan Carlos, Antenas s/n, Alcorcón, Spain.
| | - Janaina Trindade Piagette
- Cardiovascular Physiology Laboratory, Universidade Federal do Pampa, BR 472, Km 592, Uruguaiana, Rio Grande do Sul, Brazil.
| | | | - Gema Medina-Gomez
- Department of Basic Health Sciences, Universidad Rey Juan Carlos, Antenas s/n, Alcorcón, Spain.
| | - Franck Maciel Peçanha
- Cardiovascular Physiology Laboratory, Universidade Federal do Pampa, BR 472, Km 592, Uruguaiana, Rio Grande do Sul, Brazil.
| | - Dalton Valentim Vassallo
- Cardiac Electromechanical and Vascular Reactivity Laboratory, Universidade Federal do Espírito Santo, Marechal Campos, 1468, Vitória, Espírito Santo, Brazil.
| | - Marta Miguel
- Bioactivity and Food Analysis Laboratory, Instituto de Investigación en Ciencias de la Alimentación, Nicolás Cabrera, 9, Campus Universitario de Cantoblanco, Madrid, Spain.
| | - Giulia Alessandra Wiggers
- Cardiovascular Physiology Laboratory, Universidade Federal do Pampa, BR 472, Km 592, Uruguaiana, Rio Grande do Sul, Brazil.
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Yamamoto M, Motomura E, Yanagisawa R, Hoang VAT, Mogi M, Mori T, Nakamura M, Takeya M, Eto K. Evaluation of neurobehavioral impairment in methylmercury-treated KK-Ay mice by dynamic weight-bearing test. J Appl Toxicol 2018; 39:221-230. [PMID: 30175511 DOI: 10.1002/jat.3710] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/21/2018] [Accepted: 07/11/2018] [Indexed: 12/22/2022]
Abstract
Methylmercury (MeHg) is known to cause neurobehavioral impairment in human and experimental animals. We previously reported that MeHg (5 mg Hg/kg) induced severe neurobehavioral dysfunction in 4-week-old KK-Ay mice, although it is difficult to evaluate quantitatively the neurobehavioral impairment in MeHg-treated KK-Ay mice because of their obesity. The aim of this study was to evaluate MeHg-induced neurobehavioral dysfunction in KK-Ay mice using the dynamic weight-bearing test, which analyzes the animal's weight distribution between the four limbs. Male 12-week-old KK-Ay mice were treated with MeHg (5 mg Hg/kg) three times per week for 5 weeks. Body weight loss began after approximately 2 weeks of MeHg treatment, and decreased significantly at 4 weeks. Seven of the nine MeHg-treated mice exhibited overt neurological symptoms such as ataxia and gait disturbance. The weight-bearing load was lower for the forelimb than for the hindlimb at baseline and until 1 week after MeHg treatment was initiated. In weeks 2-4, the dynamic weight-bearing loads on the forelimb and hindlimb were similar. The load on the forelimb exceeded the load on the hindlimb after 5 weeks of treatment. This finding indicates that the dynamic weight-bearing test is useful for semi-quantitative evaluation of neurobehavioral impairment in MeHg-treated rodents, and is less stressful for the animals. Infiltration of CD204-positive macrophages was observed in the sciatic nerve of MeHg-treated mice, suggesting that CD204 can serve as a useful marker of tissue injury in peripheral nerves and a possible target in regenerating peripheral nerves and controlling neuropathies.
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Affiliation(s)
- Megumi Yamamoto
- Integrated Physiology Section, Department of Basic Medical Science, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto, 867-0008, Japan
| | - Eriko Motomura
- Integrated Physiology Section, Department of Basic Medical Science, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto, 867-0008, Japan
| | - Rie Yanagisawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Van Anh Thi Hoang
- Integrated Physiology Section, Department of Basic Medical Science, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto, 867-0008, Japan.,Graduate School of Environmental and Symbiotic Science, Prefectural University of Kumamoto, 3-1-100 Tsukide, Higashi-ku, Kumamoto, 862-8502, Japan
| | - Masaki Mogi
- Department of Pharmacology, Ehime University Graduate School of Medicine, Ehime, 791-0295, Japan
| | - Tomohisa Mori
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, 142-8501, Japan
| | - Masaaki Nakamura
- Department of Clinical Medicine, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto, 867-0008, Japan
| | - Motohiro Takeya
- Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan
| | - Komyo Eto
- Health and Nursing Facilities for the Aged, Jushindai, Shinwakai, 272 Ikurakitakata, Tamana, Kumamoto, 865-0041, Japan
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Shin YY, Ryu IK, Park MJ, Kim SH. The association of total blood mercury levels and overweight among Korean adolescents: analysis of the Korean National Health and Nutrition Examination Survey (KNHANES) 2010-2013. KOREAN JOURNAL OF PEDIATRICS 2018; 61:121-128. [PMID: 29713358 PMCID: PMC5924843 DOI: 10.3345/kjp.2018.61.4.121] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/22/2017] [Accepted: 10/25/2017] [Indexed: 01/29/2023]
Abstract
Purpose Obesity has been associated with higher total blood mercury levels, based on animal studies; however, studies that focus on children and adolescents are lacking. We aimed to assess the association between total blood mercury levels and the incidence of overweight and abdominal obesity in Korean adolescents. Methods The study population comprised 1,567 adolescents (793 boys and 774 girls; aged 10–19 years), who participated in the Korea National Health and Nutrition Examination Survey 2010–2013. We analyzed total blood mercury levels according to obesity status in all participants. Results The geometric mean of total blood mercury levels was 1.93 µg/L. Participants with overweight (2.20 µg/L) and obesity (2.17 µg/L) had higher levels than those with normal weight (1.86 µg/L, P<0.0001). The prevalence of overweight significantly increased with elevation of the total blood mercury quartile in both sexes. Increased incidence of abdominal obesity corresponding to increased total blood mercury level was observed in boys. After adjusting for covariates, those in the highest total blood mercury quartile were found to be at higher risk of overweight/obesity than those in the lowest quartile in both sexes (odds ratio [95% confidence interval]: boys, 3.27 [1.66–6.41]; girls, 1.90 [1.03–3.49]). The association between total blood mercury quartile and abdominal obesity was significant after controlling for covariates in boys (2.35 [1.05–5.24]). Conclusion Our results suggest an association between total blood mercury levels and overweight in Korean adolescents.
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Affiliation(s)
- Yi-Yeon Shin
- Department of Pediatrics, Inje University Sanggye Paik Hospital, Seoul, Korea
| | - In-Kyung Ryu
- Department of Pediatrics, Inje University Sanggye Paik Hospital, Seoul, Korea
| | - Mi-Jung Park
- Department of Pediatrics, Inje University Sanggye Paik Hospital, Seoul, Korea
| | - Shin-Hye Kim
- Department of Pediatrics, Inje University Sanggye Paik Hospital, Seoul, Korea
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20
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Blood mercury concentration in relation to metabolic and weight phenotypes using the KNHANES 2011-2013 data. Int Arch Occup Environ Health 2017; 91:185-193. [PMID: 29030686 DOI: 10.1007/s00420-017-1269-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/02/2017] [Indexed: 12/11/2022]
Abstract
PURPOSE We assessed the association of blood mercury concentration with metabolic and weight phenotypes. METHODS Blood mercury concentration, metabolic syndrome components, and body mass index (BMI) were measured in 6006 Korean adults (2963 men, 3043 women, mean age 44.7 ± 14.7 years), using the 2011-2013 Korean National Health and Nutrition Examination Survey data. Metabolic and weight phenotypes were classified based on BMI and metabolic syndrome (MetS) presence as metabolically healthy and normal weight (MHNW), metabolically unhealthy and normal weight (MUNW), metabolically healthy and obese (MHO), and metabolically unhealthy and obese (MUO). RESULTS The geometric mean of blood mercury concentration was 3.37 μg/L (95% CI 3.32-3.43). A higher quartile of blood mercury concentration was associated with older age, male sex, higher education, alcohol use, current smoking, low physical activity, greater energy intake, and hypertension history. After adjusting for confounding factors (age, sex, education, income, health behaviors, and energy intake), blood mercury concentration tended to increase across the MHNW, MUNW, MHO, and MUO groups in all subjects and each sex (P for trend < 0.01). Compared to the lowest mercury quartile group, adjusted odds ratios (95% CI) for MHO and MUO in those with the highest mercury quartile were, respectively, 1.67 (1.34, 2.09) and 2.02 (1.59, 2.56) in all subjects: 1.58 (1.25, 1.99) and 1.72 (1.37, 2.16) for men; 1.33 (0.94, 1.88) and 1.90 (1.34, 2.70) for women. CONCLUSIONS Blood mercury concentration was associated with both metabolic syndrome and obesity, and the association was dose dependent across metabolic and weight phenotypes.
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Roy C, Tremblay PY, Ayotte P. Is mercury exposure causing diabetes, metabolic syndrome and insulin resistance? A systematic review of the literature. ENVIRONMENTAL RESEARCH 2017; 156:747-760. [PMID: 28482296 DOI: 10.1016/j.envres.2017.04.038] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 04/25/2017] [Accepted: 04/28/2017] [Indexed: 06/07/2023]
Abstract
INTRODUCTION Several populations are exposed to mercury (Hg) via their environment, occupation or diet. It is hypothesized that Hg exposure can lead to the development of diabetes mellitus (DM). Metabolic syndrome (MS) is also a possible outcome as its symptoms are closely linked to those of DM. METHOD We conducted a systematic review of the literature by screening Web of Science, MEDLINE, SciFinder and Embase and we included original studies pertaining to the relationship of total Hg exposure (elemental, inorganic or organic) to DM, MS or insulin resistance. The studies were selected based on the PICOS (patients, intervention, comparator, outcomes and study design) criteria and their quality assessed using a nine-point scale. Study characteristics and results were extracted and presented in structured tables. We also extracted covariates entered as confounding factors to evaluate possible biases in selected studies. Finally, a weight of evidence approach was used to assess the causality of the relationship. RESULTS A total of 34 studies were included in the present review. Epidemiological data assessment suggests a possible association between total Hg concentrations in different biological matrices and incidence of DM or MS, but the relationship is not consistent. In vivo and in vitro studies support the biological plausibility of the relation between Hg exposure and DM or MS. Five out of nine of Bradford Hill's criteria were fulfilled: strength, temporality, plausibility, coherence and analogy. CONCLUSION Increased total Hg exposure may augment the risk of DM and MS, but the lack of consistency of the epidemiological evidence prevents inference of a causal relationship. Additional prospective cohort studies and careful consideration of confounding variables and interactions are required to conclude on the causal relationship of total Hg exposure on the development of DM or MS.
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Affiliation(s)
- Cynthia Roy
- Centre de Toxicologie du Québec, Institut national de santé publique du Québec (INSPQ), 945 Wolfe, Québec, QC, Canada G1V 5B3; Axe santé publique et pratiques optimales en santé, Centre de recherche du CHU de Québec, 2875 boul. Laurier, Édifice Delta 2, Bureau 600, Québec, QC, Canada G1V 2M2.
| | - Pierre-Yves Tremblay
- Centre de Toxicologie du Québec, Institut national de santé publique du Québec (INSPQ), 945 Wolfe, Québec, QC, Canada G1V 5B3; Axe santé publique et pratiques optimales en santé, Centre de recherche du CHU de Québec, 2875 boul. Laurier, Édifice Delta 2, Bureau 600, Québec, QC, Canada G1V 2M2
| | - Pierre Ayotte
- Centre de Toxicologie du Québec, Institut national de santé publique du Québec (INSPQ), 945 Wolfe, Québec, QC, Canada G1V 5B3; Axe santé publique et pratiques optimales en santé, Centre de recherche du CHU de Québec, 2875 boul. Laurier, Édifice Delta 2, Bureau 600, Québec, QC, Canada G1V 2M2; Département de médecine préventive et sociale, Université Laval, Pavillon Ferdinand-Vandry, Québec, QC, Canada G1V 0A6
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22
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Park JS, Ha KH, He K, Kim DJ. Association between Blood Mercury Level and Visceral Adiposity in Adults. Diabetes Metab J 2017; 41:113-120. [PMID: 28029015 PMCID: PMC5409010 DOI: 10.4093/dmj.2017.41.2.113] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/16/2016] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Few studies have examined the association between mercury exposure and obesity. The aim of this study is to investigate the association between blood mercury concentrations and indices of obesity in adults. METHODS A total of 200 healthy subjects, aged 30 to 64 years, who had no history of cardiovascular or malignant disease, were examined. Anthropometric and various biochemical profiles were measured. Visceral adipose tissue (VAT) was measured using dual-energy X-ray absorptiometry (DXA). RESULTS All subjects were divided into three groups according to blood mercury concentrations. Compared with the subjects in the lowest tertile of mercury, those in the highest tertile were more likely to be male; were current alcohol drinkers and smokers; had a higher body mass index (BMI), waist circumference (WC), and VAT; had higher levels of blood pressure, fasting glucose, and insulin resistance; and consumed more fish. The blood mercury concentration was significantly associated with anthropometric parameters, showing relationships with BMI, WC, and VAT. After adjusting for multiple risk factors, the odds ratios (ORs) for high mercury concentration was significantly higher in the highest VAT tertile than in the lowest VAT tertile (OR, 2.66; 95% confidence interval, 1.05 to 6.62; P<0.05). CONCLUSION The blood mercury concentration was significantly associated with VAT in healthy adults. Further studies are warranted to confirm our findings.
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Affiliation(s)
- Jong Suk Park
- Department of Endocrinology and Metabolism, Yonsei University College of Medicine, Seoul, Korea
| | - Kyoung Hwa Ha
- Cardiovascular and Metabolic Disease Etiology Research Center, Ajou University School of Medicine, Suwon, Korea
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Korea
| | - Ka He
- Department of Epidemiology and Biostatistics, Indiana University Bloomington School of Public Health, Bloomington, IN, USA
| | - Dae Jung Kim
- Cardiovascular and Metabolic Disease Etiology Research Center, Ajou University School of Medicine, Suwon, Korea
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Korea.
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Yamamoto M, Khan N, Muniroh M, Motomura E, Yanagisawa R, Matsuyama T, Vogel CFA. Activation of interleukin-6 and -8 expressions by methylmercury in human U937 macrophages involves RelA and p50. J Appl Toxicol 2016; 37:611-620. [DOI: 10.1002/jat.3411] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 09/22/2016] [Accepted: 10/03/2016] [Indexed: 01/30/2023]
Affiliation(s)
- Megumi Yamamoto
- Integrated Physiology Section, Department of Basic Medical Science; National Institute for Minamata Disease; 4058-18 Hama Minamata, Kumamoto 867-0008 Japan
| | - Noureen Khan
- Department of Epidemiology and Preventive Medicine; Kagoshima University Graduate School of Medical and Dental Sciences; 8-35-1 Sakuragaoka Kagoshima 890-8544 Japan
| | - Muflihatul Muniroh
- Department of Epidemiology and Preventive Medicine; Kagoshima University Graduate School of Medical and Dental Sciences; 8-35-1 Sakuragaoka Kagoshima 890-8544 Japan
| | - Eriko Motomura
- Integrated Physiology Section, Department of Basic Medical Science; National Institute for Minamata Disease; 4058-18 Hama Minamata, Kumamoto 867-0008 Japan
| | - Rie Yanagisawa
- Integrated Physiology Section, Department of Basic Medical Science; National Institute for Minamata Disease; 4058-18 Hama Minamata, Kumamoto 867-0008 Japan
| | - Takami Matsuyama
- Department of Immunology; Kagoshima University Graduate School of Medical and Dental Sciences; 8-35-1 Sakuragaoka Kagoshima 890-8544 Japan
| | - Christoph F. A. Vogel
- Department of Environmental Toxicology and Center for Health and the Environment; University of California; Davis CA 95616 USA
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Schumacher L, Abbott LC. Effects of methyl mercury exposure on pancreatic beta cell development and function. J Appl Toxicol 2016; 37:4-12. [PMID: 27594070 DOI: 10.1002/jat.3381] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/29/2016] [Accepted: 07/31/2016] [Indexed: 12/31/2022]
Abstract
Methyl mercury is an environmental contaminant of worldwide concern. Since the discovery of methyl mercury exposure due to eating contaminated fish as the underlying cause of the Minamata disaster, the scientific community has known about the sensitivity of the developing central nervous system to mercury toxicity. Warnings are given to pregnant women and young children to limit consumption of foods containing methyl mercury to protect the embryonic, fetal and postnatally developing central nervous system. However, evidence also suggests that exposure to methyl mercury or various forms of inorganic mercury may also affect development and function of other organs. Numerous reports indicate a worldwide increase in diabetes, particularly type 2 diabetes. Quite recently, methyl mercury has been shown to have adverse effects on pancreatic beta (β) cell development and function, resulting in insulin resistance and hyperglycemia and may even lead to the development of diabetes. This review discusses possible mechanisms by which methyl mercury exposure may adversely affect pancreatic β cell development and function, and the role that methyl mercury exposure may have in the reported worldwide increase in diabetes, particularly type 2 diabetes. While additional information is needed regarding associations between mercury exposure and specific mechanisms of the pathogenesis of diabetes in the human population, methyl mercury's adverse effects on the body's natural sources of antioxidants suggest that one possible therapeutic strategy could involve supplementation with antioxidants. Thus, it is important that additional investigation be undertaken into the role of methyl mercury exposure and reduced pancreatic β cell function. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Lauren Schumacher
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, TX, 77843-4458, USA
| | - Louise C Abbott
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, TX, 77843-4458, USA
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Lee JY, Ishida Y, Kuge S, Naganuma A, Hwang GW. Identification of substrates of F-box protein involved in methylmercury toxicity in yeast cells. FEBS Lett 2015; 589:2720-5. [PMID: 26297823 DOI: 10.1016/j.febslet.2015.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/04/2015] [Accepted: 08/06/2015] [Indexed: 12/31/2022]
Abstract
We previously reported that some of the substrate proteins recognized by Hrt3 or Ucc1, a component of Skp1/Cdc53/F-box protein ubiquitin ligase, may include proteins that are involved in the methylmercury toxicity and degraded by the proteasome. In this study, we found that Dld3 and Grs1 bound to Hrt3 and that Eno2 bound to Ucc1 using a yeast two-hybrid screening. We demonstrated that Dld3 and Grs1 are substrates that are ubiquitinated by Hrt3, and Eno2 is a substrate that is ubiquitinated by Ucc1. Moreover, any yeast showing overexpression of Dld3, Grs1, and Eno2 demonstrated higher methylmercury sensitivity. This indicates that Hrt3 and Ucc1 are involved in alleviating the methylmercury toxicity by promoting proteasomal degradation through the ubiquitination of Dld3, Grs1, and Eno2.
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Affiliation(s)
- Jin-Yong Lee
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; Laboratory of Pharmaceutical Health Sciences, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan
| | - Yosuke Ishida
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Shusuke Kuge
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; Department of Microbiology, Tohoku Pharmaceutical University, Komatsushima, Aoba-ku, Sendai 981-8558, Japan
| | - Akira Naganuma
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Gi-Wook Hwang
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan.
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Karpova NN, Lindholm JSO, Kulesskaya N, Onishchenko N, Vahter M, Popova D, Ceccatelli S, Castrén E. TrkB overexpression in mice buffers against memory deficits and depression-like behavior but not all anxiety- and stress-related symptoms induced by developmental exposure to methylmercury. Front Behav Neurosci 2014; 8:315. [PMID: 25309367 PMCID: PMC4162384 DOI: 10.3389/fnbeh.2014.00315] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/26/2014] [Indexed: 11/15/2022] Open
Abstract
Developmental exposure to low dose of methylmercury (MeHg) has a long-lasting effect on memory and attention deficits in humans, as well as cognitive performance, depression-like behavior and the hippocampal levels of the brain-derived neurotrophic factor (Bdnf)in mice. The Bdnf receptor TrkB is a key player of Bdnf signaling. Using transgenic animals, here we analyzed the effect of the full-length TrkB overexpression (TK+) on behavior impairments induced by perinatal MeHg. TK overexpression in the MeHg-exposed mice enhanced generalized anxiety and cue memory in the fear conditioning (FC) test. Early exposure to MeHg induced deficits in reversal spatial memory in the Morris water maze (MWM) test and depression-like behavior in the forced swim test (FST) in only wild-type (WT) mice but did not affect these parameters in TK+ mice. These changes were associated with TK+ effect on the increase in Bdnf 2, 3, 4 and 6 transcription in the hippocampus as well as with interaction of TK+ and MeHg factors for Bdnf 1, 9a and truncated TrkB.T1 transcripts in the prefrontal cortex. However, the MeHg-induced anxiety-like behavior in the elevated plus maze (EPM) and open field (OF) tests was ameliorated by TK+ background only in the OF test. Moreover, TK overexpression in the MeHg mice did not prevent significant stress-induced weight loss during the period of adaptation to individual housing in metabolic cages. These TK genotype-independent changes were primarily accompanied by the MeHg-induced hippocampal deficits in the activity-dependent Bdnf 1, 4 and 9a variants, TrkB.T1, and transcripts for important antioxidant enzymes glyoxalases Glo1 and Glo2 and glutathione reductase Gsr. Our data suggest a role of full-length TrkB in buffering against memory deficits and depression-like behavior in the MeHg mice but propose the involvement of additional pathways, such as the antioxidant system or TrkB.T1 signaling, in stress- or anxiety-related responses induced by developmental MeHg exposure.
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Affiliation(s)
- Nina N Karpova
- Neuroscience Center, University of Helsinki Helsinki, Finland
| | | | | | | | - Marie Vahter
- Institute of Environmental Medicine, Karolinska Institutet Stockholm, Sweden
| | - Dina Popova
- Neuroscience Center, University of Helsinki Helsinki, Finland
| | | | - Eero Castrén
- Neuroscience Center, University of Helsinki Helsinki, Finland
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