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Iba M, Kwon S, Kim C, Szabo M, Horan-Portelance L, Lopez-Ocasio M, Dagur P, Overk C, Rissman RA, Masliah E. Immunotherapy with an antibody against CD1d modulates neuroinflammation in an α-synuclein transgenic model of Lewy body like disease. J Neuroinflammation 2024; 21:93. [PMID: 38622654 PMCID: PMC11017481 DOI: 10.1186/s12974-024-03087-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 04/01/2024] [Indexed: 04/17/2024] Open
Abstract
The neuroinflammatory process in synucleinopathies of the aging population such as Parkinson's disease (PD) and dementia with Lewy bodies (DLB) involves microglial activation as well as infiltration of the CNS by T cells and natural killer T cells (NKTs). To evaluate the potential of targeting NKT cells to modulate neuroinflammation, we treated α-syn transgenic (tg) mice (e.g.: Thy1 promoter line 61) with an antibody against CD1d, which is a glycoprotein expressed in antigen presenting cells (APCs). CD1d-presented lipid antigens activate NKT cells through the interaction with T cell receptor in NKTs, resulting in the production of cytokines. Thus, we hypothesized that blocking the APC-NKT interaction with an anti-CD1d antibody might reduce neuroinflammation and neurodegeneration in models of DLB/PD. Treatment with the anti-CD1d antibody did not have effects on CD3 (T cells), slightly decreased CD4 and increased CD8 lymphocytes in the mice. Moreover, double labeling studies showed that compared to control (IgG) treated α-syn tg mice, treatment with anti-CD1d decreased numbers of CD3/interferon γ (IFN γ)-positive cells, consistent with NKTs. Further double labeling studies showed that CD1d-positive cells co-localized with the astrocytes marker GFAP and that anti-CD1d antibody reduced this effect. While in control α-syn tg mice CD3 positive cells were near astrocytes, this was modified by the treatment with the CD1d antibody. By qPCR, levels of IFN γ, CCL4, and interleukin-6 were increased in the IgG treated α-syn tg mice. Treatment with CD1d antibody blunted this cytokine response that was associated with reduced astrocytosis and microgliosis in the CNS of the α-syn tg mice treated with CD1d antibody. Flow cytometric analysis of immune cells in α-syn tg mice revealed that CD1d-tet + T cells were also increased in the spleen of α-syn tg mice, which treatment with the CD1d antibody reduced. Reduced neuroinflammation in the anti-CD1d-treated α-syn tg mice was associated with amelioration of neurodegenerative pathology. These results suggest that reducing infiltration of NKT cells with an antibody against CD1d might be a potential therapeutical approach for DLB/PD.
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Affiliation(s)
- Michiyo Iba
- Laboratory of Neurogenetics, Molecular Neuropathology Unit, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Somin Kwon
- Laboratory of Neurogenetics, Molecular Neuropathology Unit, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Changyoun Kim
- Laboratory of Neurogenetics, Molecular Neuropathology Unit, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Marcell Szabo
- Laboratory of Neurogenetics, Molecular Neuropathology Unit, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Liam Horan-Portelance
- Laboratory of Neurogenetics, Molecular Neuropathology Unit, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Maria Lopez-Ocasio
- Flow Cytometry Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Pradeep Dagur
- Flow Cytometry Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Cassia Overk
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Eliezer Masliah
- Laboratory of Neurogenetics, Molecular Neuropathology Unit, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA.
- Division of Neuroscience, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20814, USA.
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Leal-Nazaré CG, Arrifano GP, Lopes-Araújo A, Santos-Sacramento L, Barthelemy JL, Soares-Silva I, Crespo-Lopez ME, Augusto-Oliveira M. Methylmercury neurotoxicity: Beyond the neurocentric view. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 920:170939. [PMID: 38365040 DOI: 10.1016/j.scitotenv.2024.170939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/09/2024] [Accepted: 02/10/2024] [Indexed: 02/18/2024]
Abstract
Mercury is a highly toxic metal widely used in human activities worldwide, therefore considered a global public health problem. Many cases of mercury intoxication have occurred in history and represent a huge challenge nowadays. Of particular importance is its methylated form, methylmercury (MeHg). This mercurial species induces damage to several organs in the human body, especially to the central nervous system. Neurological impairments such as executive, memory, motor and visual deficits are associated with MeHg neurotoxicity. Molecular mechanisms involved in MeHg-induced neurotoxicity include excitotoxicity due to glutamatergic imbalance, disturbance in calcium homeostasis and oxidative balance, failure in synaptic support, and inflammatory response. Although neurons are largely affected by MeHg intoxication, they only represent half of the brain cells. Glial cells represent roughly 50 % of the brain cells and are key elements in the functioning of the central nervous system. Particularly, astrocytes and microglia are deeply involved in MeHg-induced neurotoxicity, resulting in distinct neurological outcomes depending on the context. In this review, we discuss the main findings on astroglial and microglial involvement as mediators of neuroprotective and neurotoxic responses to MeHg intoxication. The literature shows that these responses depend on chemical and morphophysiological features, thus, we present some insights for future investigations, considering the particularities of the context, including time and dose of exposure, brain region, and species of study.
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Affiliation(s)
- Caio Gustavo Leal-Nazaré
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil
| | - Gabriela P Arrifano
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil
| | - Amanda Lopes-Araújo
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil
| | - Leticia Santos-Sacramento
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil
| | - Jean Ludger Barthelemy
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil
| | - Isabela Soares-Silva
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil
| | - Maria Elena Crespo-Lopez
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil.
| | - Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil.
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Jiao Y, Wang G, Li D, Li H, Liu J, Yang X, Yang W. Okadaic Acid Exposure Induced Neural Tube Defects in Chicken ( Gallus gallus) Embryos. Mar Drugs 2021; 19:md19060322. [PMID: 34199615 PMCID: PMC8227060 DOI: 10.3390/md19060322] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 01/03/2023] Open
Abstract
Okadaic acid (OA) is an important liposoluble shellfish toxin distributed worldwide, and is mainly responsible for diarrheic shellfish poisoning in human beings. It has a variety of toxicities, including cytotoxicity, embryonic toxicity, neurotoxicity, and even genotoxicity. However, there is no direct evidence of its developmental toxicity in human offspring. In this study, using the chicken (Gallus gallus) embryo as the animal model, we investigated the effects of OA exposure on neurogenesis and the incidence of neural tube defects (NTDs). We found that OA exposure could cause NTDs and inhibit the neuronal differentiation. Immunofluorescent staining of pHI3 and c-Caspase3 demonstrated that OA exposure could promote cell proliferation and inhibit cell apoptosis on the developing neural tube. Besides, the down-regulation of Nrf2 and increase in reactive oxygen species (ROS) content and superoxide dismutase (SOD) activity in the OA-exposed chicken embryos indicated that OA could result in oxidative stress in early chick embryos, which might enhance the risk of the subsequent NTDs. The inhibition of bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) expression in the dorsal neural tube suggested that OA could also affect the formation of dorsolateral hinge points, which might ultimately hinder the closure of the neural tube. Transcriptome and qPCR analysis showed the expression of lipopolysaccharide-binding protein (LBP), transcription factor AP-1 (JUN), proto-oncogene protein c-fos (FOS), and C-C motif chemokine 4 (CCL4) in the Toll-like receptor signaling pathway was significantly increased in the OA-exposed embryos, suggesting that the NTDs induced by OA might be associated with the Toll-like receptor signaling pathway. Taken together, our findings could advance the understanding of the embryo–fetal developmental toxicity of OA on human gestation.
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Affiliation(s)
- Yuhu Jiao
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.J.); (D.L.); (H.L.); (J.L.)
| | - Guang Wang
- Key Laboratory for Regenerative Medicine of the Ministry of Education, Division of Histology and Embryology, Medical College, Jinan University, Guangzhou 510632, China;
| | - Dawei Li
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.J.); (D.L.); (H.L.); (J.L.)
| | - Hongye Li
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.J.); (D.L.); (H.L.); (J.L.)
| | - Jiesheng Liu
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.J.); (D.L.); (H.L.); (J.L.)
| | - Xuesong Yang
- Key Laboratory for Regenerative Medicine of the Ministry of Education, Division of Histology and Embryology, Medical College, Jinan University, Guangzhou 510632, China;
- Correspondence: (X.Y.); (W.Y); Tel.: +86-20-85228316 (X.Y.); +86-20-85221491 (W.Y)
| | - Weidong Yang
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.J.); (D.L.); (H.L.); (J.L.)
- Correspondence: (X.Y.); (W.Y); Tel.: +86-20-85228316 (X.Y.); +86-20-85221491 (W.Y)
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Methylmercury induces neuronal cell death by inducing TNF-α expression through the ASK1/p38 signaling pathway in microglia. Sci Rep 2021; 11:9832. [PMID: 33972601 PMCID: PMC8110582 DOI: 10.1038/s41598-021-89210-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/15/2021] [Indexed: 02/08/2023] Open
Abstract
We recently found that tumor necrosis factor-α (TNF-α) may be involved in neuronal cell death induced by methylmercury in the mouse brain. Here, we examined the cells involved in the induction of TNF-α expression by methylmercury in the mouse brain by in situ hybridization. TNF-α-expressing cells were found throughout the brain and were identified as microglia by immunostaining for ionized calcium binding adaptor molecule 1 (Iba1). Methylmercury induced TNF-α expression in mouse primary microglia and mouse microglial cell line BV2. Knockdown of apoptosis signal-regulating kinase 1 (ASK1), an inflammatory cytokine up-regulator that is responsible for reactive oxygen species (ROS), decreased methylmercury-induced TNF-α expression through decreased phosphorylation of p38 MAP kinase in BV2 cells. Suppression of methylmercury-induced reactive oxygen species (ROS) by antioxidant treatment largely abolished the induction of TNF-α expression and phosphorylation of p38 by methylmercury in BV2 cells. Finally, in mouse brain slices, the TNF-α antagonist (WP9QY) inhibited neuronal cell death induced by methylmercury, as did the p38 inhibitor SB203580 and liposomal clodronate (a microglia-depleting agent). These results indicate that methylmercury induces mitochondrial ROS that are involved in activation of the ASK1/p38 pathway in microglia and that this is associated with induction of TNF-α expression and neuronal cell death.
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Sato M, Toyama T, Kim MS, Lee JY, Hoshi T, Miura N, Naganuma A, Hwang GW. Increased putrescine levels due to ODC1 overexpression prevents mitochondrial dysfunction-related apoptosis induced by methylmercury. Life Sci 2020; 256:118031. [PMID: 32615186 DOI: 10.1016/j.lfs.2020.118031] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/25/2020] [Accepted: 06/27/2020] [Indexed: 12/23/2022]
Abstract
AIMS We had previously reported that addition of putrescine to the culture medium was reported to reduce methylmercury toxicity in C17.2 neural stem cells. Here, we have examined the inhibition of methylmercury-induced cytotoxicity by putrescine using ODC1-overexpressing C17.2 cells. MATERIALS AND METHODS We established stable ODC1-overexpressing C17.2 cells and evaluated methylmercury-induced apoptosis by examining the TUNEL assay and cleaved caspase-3 levels. Mitochondria-mediated apoptosis was also evaluated by reduction of mitochondrial membrane potential and recruitment of Bax and Bak to the mitochondria. KEY FINDINGS ODC is encoded by ODC1 gene, and putrescine levels in ODC1-overexpressing cells were significantly higher than in control cells. Overexpression of ODC1 and addition of putrescine to the culture medium suppressed DNA fragmentation and caspase-3 activation, which are observed when apoptosis is induced by methylmercury. Moreover, mitochondrial dysfunction and reactive oxygen species (ROS) generation, caused by methylmercury, were also inhibited by the overexpression of ODC1 and putrescine; pretreatment with ODC inhibitor, however, promoted both ROS generation and apoptosis by methylmercury. Finally, we found that Bax and Bak, the apoptosis-promoting factors, to be increased in mitochondria, following methylmercury treatment, and the same was inhibited by overexpression of ODC1. These results suggest that overexpression of ODC1 may prevent mitochondria-mediated apoptosis by methylmercury via increase of putrescine levels. SIGNIFICANCE Our findings provide important clues to clarify mechanisms involved in the defense against methylmercury toxicity and suggest novel biological functions of putrescine.
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Affiliation(s)
- Masayuki Sato
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Takashi Toyama
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Min-Seok Kim
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; Inhalation Toxicology Research Group, Korea Institute of Toxicology, 30, Baekhak1-gil Jeongeup-si, Jeollabuk-do 56212, Republic of Korea
| | - Jin-Yong Lee
- Laboratory of Pharmaceutical Health Sciences, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan
| | - Takayuki Hoshi
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Nobuhiko Miura
- Laboratory of Environmental and Molecular Toxicology, Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama, Kanagawa 245-0066, 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; Laboratory of Environmental and Health Sciences, Faculty of Pharmaceutical Sciences, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan.
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The Nuclear Protein HOXB13 Enhances Methylmercury Toxicity by Inducing Oncostatin M and Promoting Its Binding to TNFR3 in Cultured Cells. Cells 2019; 9:cells9010045. [PMID: 31878059 PMCID: PMC7017003 DOI: 10.3390/cells9010045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/20/2019] [Accepted: 12/21/2019] [Indexed: 02/06/2023] Open
Abstract
Homeobox protein B13 (HOXB13), a transcription factor, is related to methylmercury toxicity; however, the downstream factors involved in enhancing methylmercury toxicity remain unknown. We performed microarray analysis to search for downstream factors whose expression is induced by methylmercury via HOXB13 in human embryonic kidney cells (HEK293), which are useful model cells for analyzing molecular mechanisms. Methylmercury induced the expression of oncostatin M (OSM), a cytokine of the interleukin-6 family, and this was markedly suppressed by HOXB13 knockdown. OSM knockdown also conferred resistance to methylmercury in HEK293 cells, and no added methylmercury resistance was observed when both HOXB13 and OSM were knocked down. Binding of HOXB13 to the OSM gene promoter was increased by methylmercury, indicating the involvement of HOXB13 in the enhancement of its toxicity. Because addition of recombinant OSM to the medium enhanced methylmercury toxicity in OSM-knockdown cells, extracellularly released OSM was believed to enhance methylmercury toxicity via membrane receptors. We discovered tumor necrosis factor receptor (TNF) receptor 3 (TNFR3) to be a potential candidate involved in the enhancement of methylmercury toxicity by OSM. This toxicity mechanism was also confirmed in mouse neuronal stem cells. We report, for the first time, that HOXB13 is involved in enhancement of methylmercury toxicity via OSM-expression induction and that the synthesized OSM causes cell death by binding to TNFR3 extracellularly.
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Hoshi T, Toyama T, Shinozaki Y, Koizumi S, Lee JY, Naganuma A, Hwang GW. Evaluation of M1-microglial activation by neurotoxic metals using optimized organotypic cerebral slice cultures. J Toxicol Sci 2019; 44:471-479. [PMID: 31270303 DOI: 10.2131/jts.44.471] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
M1-microglia (neurotoxic microglia) regulate neuronal development and cell death and are involved in many pathologies in the brain. Although organotypic brain slice cultures are widely used to study the crosstalk between neurons and microglia, little is known about the properties of microglia in the mouse cerebral cortex slices. Here, we aimed to optimize the mouse cerebral slice cultures that reflect microglial functions and evaluate the effects of neurotoxic metals on M1-microglial activation. Most microglia in the cerebral slices prepared from postnatal day (P) 7 mice were similar to mature microglia in adult mice brains, but those in the slices prepared from P2 mice were immature, which is a conventional preparation condition. The degree of expression of M1-microglial markers (CD16 and CD32) and inflammatory cytokines (tumor necrosis factor-α and interleukin-1β) by lipopolysaccharide, a representative microglia activator, in the cerebral slices of P7 mice were higher than that in the slices of P2 mice. These results indicate that M1-microglial activation can be evaluated more accurately in the cerebral slices of P7 mice than in those of P2 mice. Therefore, we next examined the effects of various neurotoxic metals on M1-microglial activation using the cerebral slices of P7 mice and found that methylmercury stimulated the activation to M1-microglia, but arsenite, lead, and tributyltin did not induce such activation. Altogether, the optimized mouse cerebral slice cultures used in this study can be a helpful tool to study the influence of various chemicals on the central nervous system in the presence of functionally mature microglia.
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Affiliation(s)
- Takayuki Hoshi
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Takashi Toyama
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi
| | - Jin-Yong Lee
- Laboratory of Pharmaceutical Health Sciences, School of Pharmacy, Aichi Gakuin University
| | - Akira Naganuma
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Gi-Wook Hwang
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
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Takahashi T, Kim MS, Iwai-Shimada M, Hoshi T, Fujimura M, Toyama T, Fujiwara Y, Naganuma A, Hwang GW. Induction of chemokine CCL3 by NF-κB reduces methylmercury toxicity in C17.2 mouse neural stem cells. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2019; 71:103216. [PMID: 31260942 DOI: 10.1016/j.etap.2019.103216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 06/07/2019] [Accepted: 06/24/2019] [Indexed: 06/09/2023]
Abstract
Methylmercury is an environmental pollutant that shows selective toxicity to the central nervous system. We previously reported that brain-specific expression of chemokine CCL3 increases in mice administered methylmercury. However, the relationship between CCL3 and methylmercury toxicity has not been elucidated. Here, we confirmed that induction of CCL3 expression occurs before pathological change by methylmercury treatment was observed in the mouse brain. This induction was also observed in C17.2 mouse neural stem cells before methylmercury-induced cytotoxicity. In addition, cells in which CCL3 was knocked-down showed higher methylmercury sensitivity than did control cells. Moreover, activation of transcription factor NF-κB was observed following methylmercury treatment, and methylmercury-mediated induction of CCL3 expression was partially suppressed by knockdown of p65, an NF-κB subunit. Our results suggest that NF-κB plays a role in the induction of methylmercury-mediated CCL3 expression and that this action may be a cellular response to methylmercury toxicity.
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Affiliation(s)
- Tsutomu Takahashi
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan; Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1, Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Min-Seok Kim
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan; Department of Inhalation Toxicology Research, Korea Institute of Toxicology, Jeonbuk 56212, Republic of Korea
| | - Miyuki Iwai-Shimada
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan; Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Onogawa16-2, Tsukuba, Ibaraki 305-8506, Japan
| | - Takayuki Hoshi
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Masatake Fujimura
- Department of Basic Medical Science, National Institute for Minamata Disease, Kumamoto, 867-0008, Japan
| | - Takashi Toyama
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Yasuyuki Fujiwara
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1, Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Akira Naganuma
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Gi-Wook Hwang
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
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Advances in Methylmercury Toxicology and Risk Assessment. TOXICS 2019; 7:toxics7020020. [PMID: 30939776 PMCID: PMC6631574 DOI: 10.3390/toxics7020020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 03/22/2019] [Indexed: 11/16/2022]
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Methylmercury induces the expression of chemokine CCL4 via SRF activation in C17.2 mouse neural stem cells. Sci Rep 2019; 9:4631. [PMID: 30874621 PMCID: PMC6420654 DOI: 10.1038/s41598-019-41127-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 02/27/2019] [Indexed: 12/23/2022] Open
Abstract
Methylmercury is an environmental pollutant that causes specific and serious damage to the central nervous system. We have previously shown that C-C motif chemokine ligand 4 (CCL4) protects cultured neural cells from methylmercury toxicity and expression of CCL4 is specifically induced in mouse brain by methylmercury. In this study, we examined the transcriptional regulatory mechanism that induces CCL4 expression by methylmercury using C17.2 mouse neural stem cells. The promoter region of the CCL4 gene was analyzed by a reporter assay, revealing that the region up to 50 bp upstream from the transcription start site was necessary for inducing expression of CCL4 by methylmercury. Nine transcription factors that might bind to this upstream region and be involved in the induction of CCL4 expression by methylmercury were selected, and the induction of CCL4 expression by methylmercury was suppressed by the knockdown of serum response factor (SRF). In addition, the nuclear level of SRF was elevated by methylmercury, and an increase in the amount bound to the CCL4 gene promoter was also observed. Furthermore, we examined the upstream signaling pathway involved in the induction of CCL4 expression by SRF, and confirmed that activation of p38 and ERK, which are part of the MAPK pathway, are involved. These results suggest that methylmercury induces the expression of CCL4 by activating SRF via the p38 and ERK signaling pathway. Our findings are important for elucidating the mechanism involved in the brain-specific induction of CCL4 expression by methylmercury.
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Sato M, Toyama T, Lee JY, Miura N, Naganuma A, Hwang GW. Activation of ornithine decarboxylase protects against methylmercury toxicity by increasing putrescine. Toxicol Appl Pharmacol 2018; 356:120-126. [DOI: 10.1016/j.taap.2018.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 07/13/2018] [Accepted: 08/01/2018] [Indexed: 11/15/2022]
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