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Bose R, Spulber S, Ceccatelli S. The Threat Posed by Environmental Contaminants on Neurodevelopment: What Can We Learn from Neural Stem Cells? Int J Mol Sci 2023; 24:ijms24054338. [PMID: 36901772 PMCID: PMC10002364 DOI: 10.3390/ijms24054338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/03/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Exposure to chemicals may pose a greater risk to vulnerable groups, including pregnant women, fetuses, and children, that may lead to diseases linked to the toxicants' target organs. Among chemical contaminants, methylmercury (MeHg), present in aquatic food, is one of the most harmful to the developing nervous system depending on time and level of exposure. Moreover, certain man-made PFAS, such as PFOS and PFOA, used in commercial and industrial products including liquid repellants for paper, packaging, textile, leather, and carpets, are developmental neurotoxicants. There is vast knowledge about the detrimental neurotoxic effects induced by high levels of exposure to these chemicals. Less is known about the consequences that low-level exposures may have on neurodevelopment, although an increasing number of studies link neurotoxic chemical exposures to neurodevelopmental disorders. Still, the mechanisms of toxicity are not identified. Here we review in vitro mechanistic studies using neural stem cells (NSCs) from rodents and humans to dissect the cellular and molecular processes changed by exposure to environmentally relevant levels of MeHg or PFOS/PFOA. All studies show that even low concentrations dysregulate critical neurodevelopmental steps supporting the idea that neurotoxic chemicals may play a role in the onset of neurodevelopmental disorders.
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THONGSAW A, SANANMUANG R, UDNAN Y, AMPIAH-BONNEY RJ, CHAIYASITH WC. Immobilized Activated Carbon as Sorbent in Solid Phase Extraction with Cold Vapor Atomic Absorption Spectrometry for the Preconcentration and Determination of Mercury Species in Water and Freshwater Fish Samples. ANAL SCI 2019; 35:1195-1202. [DOI: 10.2116/analsci.19p164] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Arnon THONGSAW
- Department of Chemistry, Research Center for Academic Excellence in Petroleum, Petrochemical and Advanced Materials, Faculty of Science, Naresuan University
| | - Ratana SANANMUANG
- Department of Chemistry, Research Center for Academic Excellence in Petroleum, Petrochemical and Advanced Materials, Faculty of Science, Naresuan University
| | - Yuthapong UDNAN
- Department of Chemistry, Research Center for Academic Excellence in Petroleum, Petrochemical and Advanced Materials, Faculty of Science, Naresuan University
| | | | - Wipharat Chuachuad CHAIYASITH
- Department of Chemistry, Research Center for Academic Excellence in Petroleum, Petrochemical and Advanced Materials, Faculty of Science, Naresuan University
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Masjosthusmann S, Siebert C, Hübenthal U, Bendt F, Baumann J, Fritsche E. Arsenite interrupts neurodevelopmental processes of human and rat neural progenitor cells: The role of reactive oxygen species and species-specific antioxidative defense. CHEMOSPHERE 2019; 235:447-456. [PMID: 31272005 DOI: 10.1016/j.chemosphere.2019.06.123] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/15/2019] [Accepted: 06/16/2019] [Indexed: 05/10/2023]
Abstract
Arsenic exposure disturbs brain development in humans. Although developmental neurotoxicity (DNT) of arsenic has been studied in vivo and in vitro, its mode-of-action (MoA) is not completely understood. Here, we characterize the adverse neurodevelopmental effects of sodium arsenite on developing human and rat neural progenitor cells (hNPC, rNPC). Moreover, we analyze the involvement of reactive oxygen species (ROS) and the role of the glutathione (GSH)-dependent antioxidative defense for arsenite-induced DNT in a species-specific manner. We determined IC50 values for sodium arsenite-dependent (0.1-10 μM) inhibition of hNPC and rNPC migration (6.0 μM; >10 μM), neuronal (2.7 μM; 4.4 μM) and oligodendrocyte (1.1 μM; 2.0 μM) differentiation. ROS involvement was studied by quantifying the expression of ROS-regulated genes, measuring glutathione (GSH) levels, inhibiting GSH synthesis and co-exposing cells to the antioxidant N-acetylcysteine. Arsenite reduces NPC migration, neurogenesis and oligodendrogenesis of differentiating hNPC and rNPC at sub-cytotoxic concentrations. Species-specific arsenite cytotoxicity and induction of antioxidative gene expression is inversely related to GSH levels with rNPC possessing >3-fold the amount of GSH than hNPC. Inhibition of GSH synthesis increased the sensitivity towards arsenite in rNPC > hNPC. N-acetylcysteine antagonized arsenite-mediated induction of HMOX1 expression as well as reduction of neuronal and oligodendrocyte differentiation in hNPC suggesting involvement of oxidative stress in arsenite DNT. hNPC are more sensitive towards arsenite-induced neurodevelopmental toxicity than rNPC, probably due to their lower antioxidative defense capacities. This species-specific MoA data might be useful for adverse outcome pathway generation and future integrated risk assessment strategies concerning DNT.
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Affiliation(s)
- Stefan Masjosthusmann
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Clara Siebert
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Ulrike Hübenthal
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Farina Bendt
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Jenny Baumann
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany; Heinrich-Heine University, Universitätsstr. 1, 40225, Düsseldorf, Germany.
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4
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Prince LM, Aschner M, Bowman AB. Human-induced pluripotent stems cells as a model to dissect the selective neurotoxicity of methylmercury. Biochim Biophys Acta Gen Subj 2019; 1863:129300. [PMID: 30742955 DOI: 10.1016/j.bbagen.2019.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/09/2019] [Accepted: 02/01/2019] [Indexed: 01/07/2023]
Abstract
Methylmercury (MeHg) is a potent neurotoxicant affecting both the developing and mature central nervous system (CNS) with apparent indiscriminate disruption of multiple homeostatic pathways. However, genetic and environmental modifiers contribute significant variability to neurotoxicity associated with human exposures. MeHg displays developmental stage and neural lineage selective neurotoxicity. To identify mechanistic-based neuroprotective strategies to mitigate human MeHg exposure risk, it will be critical to improve our understanding of the basis of MeHg neurotoxicity and of this selective neurotoxicity. Here, we propose that human-based pluripotent stem cell cellular approaches may enable mechanistic insight into genetic pathways that modify sensitivity of specific neural lineages to MeHg-induced neurotoxicity. Such studies are crucial for the development of novel disease modifying strategies impinging on MeHg exposure vulnerability.
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Affiliation(s)
- Lisa M Prince
- School of Health Sciences, Purdue University, West Lafayette, IN 47907-2051, United States
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Aaron B Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN 47907-2051, United States.
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KIM GA, LEE Y, KIM HJ, OH HJ, KANG SK, RA JC, LEE BC. Intravenous human endothelial progenitor cell administration into aged mice enhances embryo development and oocyte quality by reducing inflammation, endoplasmic reticulum stress and apoptosis. J Vet Med Sci 2018; 80:1905-1913. [PMID: 30369585 PMCID: PMC6305508 DOI: 10.1292/jvms.18-0242] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 09/29/2018] [Indexed: 11/22/2022] Open
Abstract
Stem cell therapy has been proposed to restore the function and structure of injured tissues. In the present study, we investigated the ability of human endothelial progenitor cells (hEPCs) to attenuate ovarian aging and dysfunction. Female ICR mice aged 4 and 6 months were injected with cultured hEPCs. Cultured hEPCs were injected intravenously twice with 5 × 104 cells with a 4 day interval. After pregnant mare serum gonadotropin and human chorionic gonadotropin stimulation, oocytes and ovaries of aged mice were collected, cumulus-free oocytes were activated by SrCl2 and gene expression levels related to inflammation, apoptosis, follicle development and endoplasmic reticulum (ER) stress in ovaries were compared. Administration of hEPCs attenuated the level of inflammatory cytokines and adverse apoptotic factor, as well as reducing ER stress in the ovaries. Increased cleavage and blastocyst formation rates and cell numbers in blastocysts from hEPCs-treated aged mice vs. same aged control mice demonstrated a protective function of hEPCs against reproductive aging. Based on these data, we suggest that treatment with hEPCs attenuates reproductive aging and dysfunction potentially via regulation of inflammation, apoptosis and ER stress.
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Affiliation(s)
- Geon A KIM
- Department of Theriogenology and Biotechnology, College of
Veterinary Medicine, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yeonjae LEE
- Hankuk Academy of Foreign Studies, Yongin-si, Gyeonggi-do
17035, Republic of Korea
| | - Hyun Jin KIM
- Seoul National University, Seoul 08826, Republic of
Korea
| | - Hyun Ju OH
- Department of Theriogenology and Biotechnology, College of
Veterinary Medicine, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sung Keun KANG
- Biostar Stem Cell Research Institute, R Bio Co., Ltd., Seoul
08506, Republic of Korea
| | - Jeong Chan RA
- Biostar Stem Cell Research Institute, R Bio Co., Ltd., Seoul
08506, Republic of Korea
| | - Byeong Chun LEE
- Department of Theriogenology and Biotechnology, College of
Veterinary Medicine, Seoul National University, Seoul, 08826, Republic of Korea
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6
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Effect of Metallothionein-III on Mercury-Induced Chemokine Gene Expression. TOXICS 2018; 6:toxics6030048. [PMID: 30103553 PMCID: PMC6161308 DOI: 10.3390/toxics6030048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/02/2018] [Accepted: 08/07/2018] [Indexed: 11/16/2022]
Abstract
Mercury compounds are known to cause central nervous system disorders; however the detailed molecular mechanisms of their actions remain unclear. Methylmercury increases the expression of several chemokine genes, specifically in the brain, while metallothionein-III (MT-III) has a protective role against various brain diseases. In this study, we investigated the involvement of MT-III in chemokine gene expression changes in response to methylmercury and mercury vapor in the cerebrum and cerebellum of wild-type mice and MT-III null mice. No difference in mercury concentration was observed between the wild-type mice and MT-III null mice in any brain tissue examined. The expression of Ccl3 in the cerebrum and of Cxcl10 in the cerebellum was increased by methylmercury in the MT-III null but not the wild-type mice. The expression of Ccl7 in the cerebellum was increased by mercury vapor in the MT-III null mice but not the wild-type mice. However, the expression of Ccl12 and Cxcl12 was increased in the cerebrum by methylmercury only in the wild-type mice and the expression of Ccl3 in the cerebellum was increased by mercury vapor only in the wild-type mice. These results indicate that MT-III does not affect mercury accumulation in the brain, but that it affects the expression of some chemokine genes in response to mercury compounds.
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Sampaio GSA, Oliveira KRHM, Kauffmann N, do Nascimento JLM, Souza GS, Gomes BD, de Lima SMA, Silveira LCL, Rocha FAF, Herculano AM. Methylmercury alters the number and topography of NO-synthase positive neurons in embryonic retina: Protective effect of alpha-tocopherol. Toxicol In Vitro 2018; 53:89-98. [PMID: 30075186 DOI: 10.1016/j.tiv.2018.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/25/2018] [Accepted: 07/30/2018] [Indexed: 10/28/2022]
Abstract
Vertebrate retina has been shown to be an important target for mercury toxicity and very studies have shown the effect of mercury on the retinal ontogenesis. The nitrergic system plays an important role in the retinal development. The current work studied the effects of methylmercury (MeHg) exposure on the NO-synthase positive neurons (NADPH-diaphorase neurons or NADPH-d+) of the chick retinal ganglion cell layer at embryonic E15 and postnatal P1 days. Retinal flat mounts were stained for NADPH-diaphorase histochemistry and mosaic properties of NADPH-d + were studied by plotting isodensity maps and employing density recovery profile technique. It was also evaluated the protective effect of alpha-tocopherol treatment on retinal tissues exposed to MeHg. MeHg exposure decreased the density of NADPH-d + neurons and altered cell mosaic properties at E15 but had very little or no effect at P1 retinas. Alpha-tocopherol has a protective effect against MeHg exposure at E15. MeHg alterations and alpha-tocopherol protective effect in embryonic retinas were demonstrated to be at work in experimental conditions. MeHg effect in the early phases of visual system development in natural conditions might use the nitrergic pathway and supplementary diet could have a protective effect. At later stages, this mechanism seems to be naturally protected.
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Affiliation(s)
- Gabriela S A Sampaio
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
| | | | - Nayara Kauffmann
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
| | - José Luiz M do Nascimento
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil; Universidade Ceuma, São Luís, Maranhão, Brazil
| | - Givago S Souza
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil; Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Bruno D Gomes
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
| | | | - Luiz Carlos L Silveira
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil; Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Pará, Brazil; Universidade Ceuma, São Luís, Maranhão, Brazil
| | | | - Anderson M Herculano
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
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8
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Sequestosome1/p62 protects mouse embryonic fibroblasts against low-dose methylercury-induced cytotoxicity and is involved in clearance of ubiquitinated proteins. Sci Rep 2017; 7:16735. [PMID: 29196648 PMCID: PMC5711938 DOI: 10.1038/s41598-017-17112-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 11/22/2017] [Indexed: 01/07/2023] Open
Abstract
Methylmercury (MeHg) is a widely distributed environmental pollutant that causes a series of cytotoxic effects. However, molecular mechanisms underlying MeHg toxicity are not fully understood. Here, we report that sequestosome1/p62 protects mouse embryonic fibroblasts (MEFs) against low-dose MeHg cytotoxicity via clearance of MeHg-induced ubiquitinated proteins. p62 mRNA and protein expression in MEFs were temporally induced by MeHg exposure p62-deficient MEFs exhibited higher sensitivity to MeHg exposure compared to their wild-type (WT) counterparts. An earlier and higher level of accumulation of ubiquitinated proteins was detected in p62-deficient cells compared with WT MEFs. Confocal microscopy revealed that p62 and ubiquitinated proteins co-localized in the perinuclear region of MEFs following MeHg treatment. Further analysis of MEFs revealed that ubiquitinated proteins co-localized with LC3-positive puncta upon co-treatment with MeHg and chloroquine, an autophagy inhibitor. In contrast, there was minimal co-localization in p62-deficient MEFs. The present study, for the first time, examined the expression and distribution of p62 and ubiquitinated proteins in cells exposed to low-dose MeHg. Our findings suggest that p62 is crucial for cytoprotection against MeHg-induced toxicity and is required for MeHg-induced ubiquitinated protein clearance.
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9
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Wang H, Chen B, Zhu S, Yu X, He M, Hu B. Chip-Based Magnetic Solid-Phase Microextraction Online Coupled with MicroHPLC–ICPMS for the Determination of Mercury Species in Cells. Anal Chem 2015; 88:796-802. [DOI: 10.1021/acs.analchem.5b03130] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Han Wang
- Key Laboratory of Analytical Chemistry
for Biology and Medicine, Ministry of Education, Department
of Chemistry, Wuhan University, Wuhan 430072, China
| | - Beibei Chen
- Key Laboratory of Analytical Chemistry
for Biology and Medicine, Ministry of Education, Department
of Chemistry, Wuhan University, Wuhan 430072, China
| | - Siqi Zhu
- Key Laboratory of Analytical Chemistry
for Biology and Medicine, Ministry of Education, Department
of Chemistry, Wuhan University, Wuhan 430072, China
| | - Xiaoxiao Yu
- Key Laboratory of Analytical Chemistry
for Biology and Medicine, Ministry of Education, Department
of Chemistry, Wuhan University, Wuhan 430072, China
| | - Man He
- Key Laboratory of Analytical Chemistry
for Biology and Medicine, Ministry of Education, Department
of Chemistry, Wuhan University, Wuhan 430072, China
| | - Bin Hu
- Key Laboratory of Analytical Chemistry
for Biology and Medicine, Ministry of Education, Department
of Chemistry, Wuhan University, Wuhan 430072, China
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10
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Watanabe J, Matsumoto M, Kageyama H, Murai N, Sasaki S, Hirako S, Wada N, Arata S, Shioda S. Ghrelin suppresses proliferation of fetal neural progenitor cells, and induces their differentiation into neurons. Peptides 2015; 69:40-6. [PMID: 25828736 DOI: 10.1016/j.peptides.2015.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 03/19/2015] [Indexed: 01/02/2023]
Abstract
Although considerable progress has been made in understanding how the temporal and regional control of neural progenitor cells (NPCs) dictates their fate, their key regulators during neural development are still unknown. Ghrelin, which is isolated from porcine stomach extract, is an endogenous ligand for the growth hormone secretagogue receptor (GHS-R). The widespread expression of ghrelin and GHS-R in the central nervous system during development suggests that ghrelin may be involved in developmental neural growth. However, its role in regulating fetal NPCs is still unclear. In this study, we investigated the effects of ghrelin on primary cultured NPCs derived from fetal mouse telencephalon. The expressions of both ghrelin and its receptor were observed in NPCs using RT-PCR, immunoblotting and immunocytostaining. Interestingly, the exposure of fetal NPCs to ghrelin at concentrations of 10(-7) and 10(-9)M suppressed their proliferation, and caused them to differentiate into neurons and to extend neurites. These results strongly suggest that ghrelin plays an autocrine modulatory role in fetal neural development.
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Affiliation(s)
- Jun Watanabe
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan; Center for Biotechnology, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Minako Matsumoto
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Haruaki Kageyama
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan; Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Norimitsu Murai
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Shun Sasaki
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Satoshi Hirako
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Nobuhiro Wada
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Satoru Arata
- Center for Biotechnology, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Seiji Shioda
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
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11
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Watanabe J, Nakamachi T, Ohtaki H, Naganuma A, Shioda S, Nakajo S. Low dose of methylmercury (MeHg) exposure induces caspase mediated-apoptosis in cultured neural progenitor cells. J Toxicol Sci 2014; 38:931-5. [PMID: 24213013 DOI: 10.2131/jts.38.931] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Methylmercury (MeHg) is an environmental pollutant known to cause neurobehavioral defects, and it is especially toxic to the developing brain. In contrast to the adult, the developing brain consists of a large number of dividing neural progenitor cells (NPCs), which are vulnerable targets for MeHg toxicity. In a previous study, we showed that the embryonic NPCs from the telencephalon are more sensitive to MeHg than other neural cells. Here, we investigated the mechanism of cell death underlying MeHg toxicity. We observed that exposure of NPCs to MeHg caused DNA laddering in a dose- and time-dependent manner. Decreased pro-caspase3 and increased cleaved-caspase3 protein was observed 3-12 hours after incubation of NPCs with MeHg. Moreover, the caspase-inhibitor Z-VAD FMK significantly suppressed MeHg-induced cell death in a dose-dependent manner. These results suggest that environmentally relevant levels of MeHg exposure induce apoptosis in NPCs.
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Affiliation(s)
- Jun Watanabe
- Department of Anatomy, Showa University School of Medicine
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12
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Cordero-Herrera I, Cuello S, Goya L, Madrid Y, Bravo L, Cámara C, Ramos S. Molecular mechanisms involved in the protective effect of selenocystine against methylmercury-induced cell death in human HepG2 cells. Food Chem Toxicol 2013; 59:554-63. [DOI: 10.1016/j.fct.2013.06.057] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 06/26/2013] [Accepted: 06/28/2013] [Indexed: 12/22/2022]
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13
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Jebbett NJ, Hamilton JW, Rand MD, Eckenstein F. Low level methylmercury enhances CNTF-evoked STAT3 signaling and glial differentiation in cultured cortical progenitor cells. Neurotoxicology 2013; 38:91-100. [PMID: 23845766 DOI: 10.1016/j.neuro.2013.06.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/26/2013] [Accepted: 06/28/2013] [Indexed: 01/18/2023]
Abstract
Although many previous investigations have studied how mercury compounds cause cell death, sub-cytotoxic levels may affect mechanisms essential for the proper development of the nervous system. The present study investigates whether low doses of methylmercury (MeHg) and mercury chloride (HgCl2) can modulate the activity of JAK/STAT signaling, a pathway that promotes gliogenesis. We report that sub-cytotoxic doses of MeHg enhance ciliary neurotrophic factor (CNTF) evoked STAT3 phosphorylation in human SH-SY5Y neuroblastoma and mouse cortical neural progenitor cells (NPCs). This effect is specific for MeHg, since HgCl2 fails to enhance JAK/STAT signaling. Exposing NPCs to these low doses of MeHg (30-300nM) enhances CNTF-induced expression of STAT3-target genes such as glial fibrillary acidic protein (GFAP) and suppressors of cytokine signaling 3 (SOCS3), and increases the proportion of cells expressing GFAP following 2 days of differentiation. Higher, near-cytotoxic concentrations of MeHg and HgCl2 inhibit STAT3 phosphorylation and lead to increased production of superoxide. Lower concentrations of MeHg effective in enhancing JAK/STAT signaling (30nM) do not result in a detectable increase in superoxide nor increased expression of the oxidant-responsive genes, heme oxygenase 1, heat shock protein A5 and sirtuin 1. These findings suggest that low concentrations of MeHg inappropriately enhance STAT3 phosphorylation and glial differentiation, and that the mechanism causing this enhancement is distinct from the reactive oxygen species-associated cell death observed at higher concentrations of MeHg and HgCl2.
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Affiliation(s)
- Nathan J Jebbett
- University of Vermont, Department of Neurological Sciences, Burlington, VT, United States
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14
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Zhu XY, Urbieta-Caceres V, Krier JD, Textor SC, Lerman A, Lerman LO. Mesenchymal stem cells and endothelial progenitor cells decrease renal injury in experimental swine renal artery stenosis through different mechanisms. Stem Cells 2013; 31:117-25. [PMID: 23097349 DOI: 10.1002/stem.1263] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 09/07/2012] [Accepted: 09/23/2012] [Indexed: 12/28/2022]
Abstract
Endothelial progenitor cells (EPC) and mesenchymal stem cells (MSC) augment tissue repair but possess slightly different properties. How the cellular phenotype affects the efficacy of this approach in renovascular disease is incompletely understood. This study tested the hypothesis that EPC and MSC protect the poststenotic kidney by blunting different disease pathways. Peripheral blood EPC and adipose-derived MSC were expanded and characterized by cell surface markers (e.g., CD34/kinase insert domain receptor, or CD44/CD90). Single-kidney hemodynamics and function were assessed in pigs after 10 weeks of renal artery stenosis (RAS) treated 4 weeks earlier with an intrarenal infusion of vehicle (n = 7), EPC (RAS+EPC) or MSC (RAS+MSC) (both 10 × 10(6), n = 6), and normal controls (n = 7). Kidney disease mechanisms were evaluated ex vivo. The ability of EPC and MSC to attenuate endoplasmic reticulum (ER) stress was also studied in isolated ER and in tubular cells cocultured with EPC and MSC. Glomerular filtration rate in RAS was lower than controls, increased in RAS+EPC, and further improved in RAS+MSC, although both improved renal blood flow similarly. EPC prominently enhanced renal growth factor expression and decreased oxidative stress, while MSC more significantly attenuated renal inflammation, ER stress, and apoptosis. Furthermore, MSC induced a greater decrease in caspase-3 and CHOP expression in cultured tubular cells through mechanisms involving cell contact. EPC and MSC achieve a comparable decrease of kidney injury in RAS by different mechanisms, although MSC elicited slightly superior improvement of renal function. These results support development of cell-based approaches for management of renovascular disease and suggest cell selection based on the underlying pathophysiology of kidney injury.
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Affiliation(s)
- Xiang-Yang Zhu
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota 55905, USA
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15
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Lee JY, Hwang GW, Kim MS, Takahashi T, Naganuma A. Methylmercury induces a brain-specific increase in chemokine CCL4 expression in mice. J Toxicol Sci 2013. [PMID: 23208444 DOI: 10.2131/jts.37.1279] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Expression of the chemokine genes Ccl2, Ccl4, Ccl7, Ccl9, and Ccl12 is increased in cerebellum of mice treated with methylmercury. To investigate the effect of methylmercury on other tissues and organs, levels of chemokine mRNA were investigated in mouse cerebrum, kidney, liver, and spleen. In cerebrum, expression levels of the five chemokines were significantly increased after methylmercury treatment. In kidney, expression levels of Ccl2, Ccl7, Ccl9, and Ccl12, but not Ccl4 were increased. No significant effects were seen on mRNA levels of the chemokines in liver and spleen. Thus, although methylmercury increases the expression levels of multiple chemokines in the brain and kidney, expression of Ccl4 increases only in the brain. Hence, this phenomenon may be involved in methylmercury toxicity specific to the central nervous system.
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Affiliation(s)
- Jin-Yong Lee
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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Methylmercury-induced changes in target organs of suckling rat pups. ACTA ACUST UNITED AC 2012; 64:605-9. [DOI: 10.1016/j.etp.2010.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Revised: 11/24/2010] [Accepted: 12/01/2010] [Indexed: 11/22/2022]
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17
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Hwang GW, Tobita M, Takahashi T, Kuge S, Kita K, Naganuma A. siRNA-mediated AMPKalpha1 subunit gene PRKAA1 silencing enhances methylmercury toxicity in HEK293 cells. J Toxicol Sci 2011; 35:601-4. [PMID: 20686348 DOI: 10.2131/jts.35.601] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The environmental pollutant methylmercury is a potent neurotoxin. The mechanisms of toxicity and biological defense remain largely unknown. We found that inhibiting the expression of PRKAA1 (AMPKalpha1), an activated subunit of AMP-activated protein kinase (AMPK), increased susceptibility of HEK293 cells to methylmercury toxicity. Treatment of the cells with AICAR (5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside), an AMPK activator, reduced the methylmercury toxicity. Here, we suggest for the first time that the activation (phosphorylation) of AMPK may play an important role in reducing the toxicity of methylmercury.
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Affiliation(s)
- Gi-Wook Hwang
- Laboratory of Molecular and Biochemical Toxicology, Department of Microbiology, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi, Japan
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Kell DB. Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples. Arch Toxicol 2010; 84:825-89. [PMID: 20967426 PMCID: PMC2988997 DOI: 10.1007/s00204-010-0577-x] [Citation(s) in RCA: 286] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 07/14/2010] [Indexed: 12/11/2022]
Abstract
Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.
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Affiliation(s)
- Douglas B Kell
- School of Chemistry and the Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester M1 7DN, UK.
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Molecular mechanisms of methylmercury-induced cell death in human HepG2 cells. Food Chem Toxicol 2010; 48:1405-11. [PMID: 20226830 DOI: 10.1016/j.fct.2010.03.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 03/03/2010] [Accepted: 03/08/2010] [Indexed: 12/29/2022]
Abstract
Methylmercury (MeHg) has been suggested to exert cytotoxicity through multiple mechanisms, but the precise biochemical machinery has not been fully defined. This study was aimed at investigating the time-course (0-24h) effect of 2mg/L MeHg on cell death in human HepG2 cells. MeHg decreased cell viability in a time-dependent manner, which was concomitant with increased LDH leakage, reduced GSH levels, CAT activity and altered activity of the antioxidant enzymes GPx and GR at the longest times of incubation (16 and 24h). Activity of the detoxifying enzyme GST was also early enhanced (2h). Caspase-3 activity reached a maximum value at 8h and continued increased up to 24h. This feature was preceded by an enhancement in the caspase-9 activity (2h), whereas caspase-8 activity remained unchanged. MeHg early diminished Bcl-x(L)/Bcl-x(S) ratio and increased levels of the pro-apoptotic Bax and Bad. Moreover, MeHg-induced cytotoxicity was completely inhibited by the antioxidants (GSH and NAC) and notably by the mitochondrial complex I inhibitor rotenone, but not by the NADH oxidase inhibitor DPI. In summary, MeHg induced an oxidative stress responsible for apoptosis in HepG2 cells through direct activation of the caspase cascade and altered the cellular antioxidant and detoxificant enzymatic system to later provoke necrosis at later stages.
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Lee JY, Hwang GW, Naganuma A. Rip1 enhances methylmercury toxicity through production of reactive oxygen species (ROS) in budding yeast. J Toxicol Sci 2010; 34:715-7. [PMID: 19952509 DOI: 10.2131/jts.34.715] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Reactive oxygen species (ROS) produced by mitochondria are potentially involved in the manifestation of methylmercury toxicity. However, the molecular mechanism underlying methylmercury toxicity remains poorly understood. We examined susceptibility to methylmercury in yeast strains that each lacked one of components of the mitochondrial electron transport system. Resistance to methylmercury was exhibited only by yeast that lacked Rip1, a component of electron transport system complex III. Resistance to methylmercury in Rip1-deficient yeast was independent of the activity of electron transport system complex III. Also, ROS levels induced by methylmercury in Rip1-deficient yeast were significantly lower than in wild-type yeast. Thus, Rip1 is potentially involved in ROS production through an as-yet unknown mechanism that is independent of the activity of electron transport system complex III, thereby enhancing methylmercury toxicity.
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Affiliation(s)
- Jin-Yong Lee
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
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Hwang GW, Oh SE, Takahashi T, Lee JY, Naganuma A. siRNA-mediated knockdown of the melanocortin 2 receptor accessory protein 2 (MRAP2) gene confers resistance to methylmercury on HEK293 cells. J Toxicol Sci 2010; 35:947-50. [DOI: 10.2131/jts.35.947] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Gi-Wook Hwang
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Seong-Eun Oh
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Tsutomu Takahashi
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Jin-Yong Lee
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Akira Naganuma
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
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