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Ishida K, Takeda K, Takehara Y, Takabayashi T, Miyara M, Sanoh S, Kawai H, Ohta S, Kotake Y. Methylmercury Decreases AMPA Receptor Subunit GluA2 Levels in Cultured Rat Cortical Neurons. Biol Pharm Bull 2023; 46:292-300. [PMID: 36724957 DOI: 10.1248/bpb.b22-00744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Methylmercury (MeHg) is a well-known environmental pollutant that has harmful effects on the central nervous systems of humans and animals. The molecular mechanisms of MeHg-induced neurotoxicity at low concentrations are not fully understood. Here, we investigated the effects of low-concentration MeHg on the cell viability, Ca2+ homeostasis, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA2 levels, which determine Ca2+ permeability of AMPA receptors, in rat primary cortical neurons. Exposure of cortical neurons to 100 and 300 nM MeHg for 7 d resulted in a decrease in GluA2 levels, an increase in basal intracellular Ca2+ concentration, increased phosphorylation levels of extracellular signal-regulated kinase (ERK)1/2 and p38, and decreased cell viability. Moreover, glutamate stimulation exacerbated the decrease in cell viability and increased intracellular Ca2+ levels in MeHg-treated neurons compared to control neurons. MeHg-induced neuronal cell death was ameliorated by 1-naphthyl acetyl spermine, a specific antagonist of Ca2+-permeable, GluA2-lacking AMPA receptors. Our findings raise the possibility that decreased neuronal GluA2 levels and the subsequent increase in intracellular Ca2+ concentration may contribute to MeHg-induced neurotoxicity.
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Affiliation(s)
- Keishi Ishida
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Kazuki Takeda
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Yuki Takehara
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | | | - Masatsugu Miyara
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Seigo Sanoh
- Graduate School of Biomedical and Health Sciences, Hiroshima University.,Wakayama Medical University
| | - Hidehiko Kawai
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Shigeru Ohta
- Graduate School of Biomedical and Health Sciences, Hiroshima University.,Wakayama Medical University
| | - Yaichiro Kotake
- Graduate School of Biomedical and Health Sciences, Hiroshima University
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2
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Carmona A, Roudeau S, Ortega R. Molecular Mechanisms of Environmental Metal Neurotoxicity: A Focus on the Interactions of Metals with Synapse Structure and Function. TOXICS 2021; 9:toxics9090198. [PMID: 34564349 PMCID: PMC8471991 DOI: 10.3390/toxics9090198] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 02/07/2023]
Abstract
Environmental exposure to neurotoxic metals and metalloids such as arsenic, cadmium, lead, mercury, or manganese is a global health concern affecting millions of people worldwide. Depending on the period of exposure over a lifetime, environmental metals can alter neurodevelopment, neurobehavior, and cognition and cause neurodegeneration. There is increasing evidence linking environmental exposure to metal contaminants to the etiology of neurological diseases in early life (e.g., autism spectrum disorder) or late life (e.g., Alzheimer’s disease). The known main molecular mechanisms of metal-induced toxicity in cells are the generation of reactive oxygen species, the interaction with sulfhydryl chemical groups in proteins (e.g., cysteine), and the competition of toxic metals with binding sites of essential metals (e.g., Fe, Cu, Zn). In neurons, these molecular interactions can alter the functions of neurotransmitter receptors, the cytoskeleton and scaffolding synaptic proteins, thereby disrupting synaptic structure and function. Loss of synaptic connectivity may precede more drastic alterations such as neurodegeneration. In this article, we will review the molecular mechanisms of metal-induced synaptic neurotoxicity.
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3
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Abstract
Lead (Pb2+) is a non-essential metal with numerous industrial applications that have led to ts ubiquity in the environment. Thus, not only occupational-exposed individuals' health is compromised, but also that of the general population and in particular children. Notably, although the central nervous system is particularly susceptible to Pb2+, other systems are affected as well. The present study focuses on molecular mechanisms that underlie the effects that arise from the presence of Pb2+ in situ in the brain, and the possible toxic effects that follows. As the brain barriers represent the first target of systemic Pb2+, mechanisms of Pb2+ entry into the brain are discussed, followed by a detailed discussion on neurotoxic mechanisms, with special emphasis on theories of ion mimicry, mitochondrial dysfunction, redox imbalance, and neuroinflammation. Most importantly, the confluence and crosstalk between these events is combined into a cogent mechanism of toxicity, by intertwining recent and old evidences from humans, in vitro cell culture and experimental animals. Finally, pharmacological interventions, including chelators, antioxidants substances, anti-inflammatory drugs, or their combination are reviewed as integrated approaches to ameliorate Pb2+ harmful effects in both developing or adult organisms.
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Affiliation(s)
- Miriam B. Virgolini
- IFEC CONICET. IFEC-CONICET. Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Haya de la Torre y Medina Allende, Ciudad Universitaria, 5016, Córdoba, Argentina
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA and IM Sechenov First Moscow State Medical University (Sechenov University), 119146, Moscow, Russia
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4
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Ding JJ, Zou RX, He HM, Lou ZY, Xu Y, Wang HL. Pb inhibits hippocampal synaptic transmission via cyclin-dependent kinase-5 dependent Synapsin 1 phosphorylation. Toxicol Lett 2018; 296:125-131. [PMID: 30121340 DOI: 10.1016/j.toxlet.2018.08.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/12/2018] [Accepted: 08/14/2018] [Indexed: 12/18/2022]
Abstract
Lead (Pb) exposure impairs the nervous system, of which the injury of cognitive development is obvious. But the mechanism of Pb induced disorders of neuro-transmission remain elusive. In this study, primary hippocampal neurons were exposed to Pb at the dosage of 5 μM from days in vitro (DIV) 3 to DIV14 and the electrophysiological recordings were performed at DIV14. Sprague-Dawley (SD) rat pups were exposed to Pb from parturition to weaning indirectly from their mothers whose drinking water containing 250 ppm Pb, then directly exposed to Pb at the dosage of 250 ppm from postnatal day (PND) 21 to PND30. The results showed that Pb significantly decreased the frequency of both miniature excitatory postsynaptic current (mEPSC) and miniature inhibitory postsynaptic current (mIPSC) in cultured hippocampal neurons. Paird-pulse facilitation (PPF) recordings showed there was significant increase in Pb-exposed group. The increase of the magnitude of PPF (the ratio of second to first response amplitude) further confirmed that Pb reduced presynaptic neuro-transmission. By transmission electron microscope, it found that Pb disarranged presynaptic vesicles distribution and decreased the density of presynaptic vesicles. Moreover, it was interestingly found that phosphorylation of Synapsin1, which was phosphorylated by CDK5, has been decreased upon Pb exposure. With the treatment of R-Roscovitine (Ro), an inhibitor of CDK5, it was detected that Pb induced mEPSC and mIPSC frequency reduction have been reversed. Together, our results suggested that Pb disrupted the distribution of synaptic vesicles and impaired the neurotransmitter release, which was dependent on the phosphorylation level of Synapsin 1 via CDK5. This study will help for elucidation of environmental Pb-induced neuronal disorders.
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Affiliation(s)
- Jin-Jun Ding
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Rong-Xin Zou
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Hui-Ming He
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Zhi-Yi Lou
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Yi Xu
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Hui-Li Wang
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China.
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5
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Ishida K, Aoki K, Takishita T, Miyara M, Sakamoto S, Sanoh S, Kimura T, Kanda Y, Ohta S, Kotake Y. Low-Concentration Tributyltin Decreases GluR2 Expression via Nuclear Respiratory Factor-1 Inhibition. Int J Mol Sci 2017; 18:ijms18081754. [PMID: 28800112 PMCID: PMC5578144 DOI: 10.3390/ijms18081754] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/03/2017] [Accepted: 08/09/2017] [Indexed: 12/19/2022] Open
Abstract
Tributyltin (TBT), which has been widely used as an antifouling agent in paints, is a common environmental pollutant. Although the toxicity of high-dose TBT has been extensively reported, the effects of low concentrations of TBT are relatively less well studied. We have previously reported that low-concentration TBT decreases α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptor subunit 2 (GluR2) expression in cortical neurons and enhances neuronal vulnerability to glutamate. However, the mechanism of this TBT-induced GluR2 decrease remains unknown. Therefore, we examined the effects of TBT on the activity of transcription factors that control GluR2 expression. Exposure of primary cortical neurons to 20 nM TBT for 3 h to 9 days resulted in a decrease in GluR2 mRNA expression. Moreover, TBT inhibited the DNA binding activity of nuclear respiratory factor-1 (NRF-1), a transcription factor that positively regulates the GluR2. This result indicates that TBT inhibits the activity of NRF-1 and subsequently decreases GluR2 expression. In addition, 20 nM TBT decreased the expression of genes such as cytochrome c, cytochrome c oxidase (COX) 4, and COX 6c, which are downstream of NRF-1. Our results suggest that NRF-1 inhibition is an important molecular action of the neurotoxicity induced by low-concentration TBT.
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Affiliation(s)
- Keishi Ishida
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
- Research Fellow of the Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan.
| | - Kaori Aoki
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
| | - Tomoko Takishita
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
| | - Masatsugu Miyara
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
| | - Shuichiro Sakamoto
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
| | - Seigo Sanoh
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
| | - Tomoki Kimura
- Faculty of Science and Engineering, Setsunan University, 17-8 Ikedanakamachi, Neyagawa 572-8508, Japan.
| | - Yasunari Kanda
- Division of Pharmacology, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
| | - Shigeru Ohta
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
| | - Yaichiro Kotake
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
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6
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Carbofuran causes neuronal vulnerability to glutamate by decreasing GluA2 protein levels in rat primary cortical neurons. Arch Toxicol 2017; 92:401-409. [PMID: 28725974 DOI: 10.1007/s00204-017-2018-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 06/19/2017] [Indexed: 10/19/2022]
Abstract
Glutamate receptor 2 (GluA2/GluR2) is one of the four subunits of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR); an increase in GluA2-lacking AMPARs contributes to neuronal vulnerability to excitotoxicity because of the receptor's high Ca2+ permeability. Carbofuran is a carbamate pesticide used in agricultural areas to increase crop productivity. Due to its broad-spectrum action, carbofuran has also been used as an insecticide, nematicide, and acaricide. In this study, we investigated the effect of carbofuran on GluA2 protein expression. The 9-day treatment of rat primary cortical neurons with 1 µM and 10 µM carbofuran decreased GluA2 protein expression, but not that of GluA1, GluA3, or GluA4 (i.e., other AMPAR subunits). Decreased GluA2 protein expression was also observed on the cell surface membrane of 10 µM carbofuran-treated neurons, and these neurons showed an increase in 25 µM glutamate-triggered Ca2+ influx. Treatment with 50 µM glutamate, which did not affect the viability of control neurons, significantly decreased the viability of 10 µM carbofuran-treated neurons, and this effect was abolished by pre-treatment with 300 µM 1-naphthylacetylspermine, an antagonist of GluA2-lacking AMPAR. At a concentration of 100 µM, but not 1 or 10 µM, carbofuran significantly decreased acetylcholine esterase activity, a well-known target of this chemical. These results suggest that carbofuran decreases GluA2 protein expression and increases neuronal vulnerability to glutamate toxicity at concentrations that do not affect acetylcholine esterase activity.
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7
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Ishida K, Saiki T, Umeda K, Miyara M, Sanoh S, Ohta S, Kotake Y. Prenatal Exposure to Tributyltin Decreases GluR2 Expression in the Mouse Brain. Biol Pharm Bull 2017; 40:1121-1124. [PMID: 28674256 DOI: 10.1248/bpb.b17-00209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tributyltin (TBT), a common environmental contaminant, is widely used as an antifouling agent in paint. We previously reported that exposure of primary cortical neurons to TBT in vitro decreased the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit glutamate receptor 2 (GluR2) expression and subsequently increased neuronal vulnerability to glutamate. Therefore, to identify whether GluR2 expression also decreases after TBT exposure in vivo, we evaluated the changes in GluR2 expression in the mouse brain after prenatal or postnatal exposure to 10 and 25 ppm TBT through pellet diets. Although the mean feed intake and body weight did not decrease in TBT-exposed mice compared with that in control mice, GluR2 expression in the cerebral cortex and hippocampus decreased after TBT exposure during the prenatal period. These results indicate that a decrease in neuronal GluR2 may be involved in TBT-induced neurotoxicity, especially during the fetal period.
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Affiliation(s)
- Keishi Ishida
- Graduate School of Biomedical and Health Sciences, Hiroshima University.,Research Fellow of the Japan Society for the Promotion of Science
| | - Takashi Saiki
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Kanae Umeda
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Masatsugu Miyara
- Graduate School of Biomedical and Health Sciences, Hiroshima University.,Global Career Design Center, Hiroshima University
| | - Seigo Sanoh
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Shigeru Ohta
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Yaichiro Kotake
- Graduate School of Biomedical and Health Sciences, Hiroshima University
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8
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Ishida K, Kotake Y, Sanoh S, Ohta S. Lead-Induced ERK Activation Is Mediated by GluR2 Non-containing AMPA Receptor in Cortical Neurons. Biol Pharm Bull 2017; 40:303-309. [PMID: 28250271 DOI: 10.1248/bpb.b16-00784] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lead is a persistent environmental pollutant and exposure to high environmental levels causes various deleterious toxicities, especially to the central nervous system (CNS). The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor that is devoid of the glutamate receptor 2 (GluR2) subunit is Ca2+-permeable, which increases the neuronal vulnerability to excitotoxicity. We have previously reported that long-term exposure of rat cortical neurons to lead acetate induces decrease of GluR2 expression. However, it is not clarified whether lead-induced GluR2 decrease is involved in neurotoxicity. Therefore, we investigated the contribution of GluR2 non-containing AMPA receptor to lead-induced neurotoxic events. Although the expression of four AMPA receptor subunits (GluR1, GluR2, GluR3, and GluR4) was decreased by lead exposure, the decrease in GluR2 expression was remarkable among four subunits. Lead-induced neuronal cell death was rescued by three glutamate receptor antagonists, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, a non-selective AMPA receptor blocker), MK-801 (N-methyl-D-aspartate (NMDA) receptor blocker), and 1-naphthyl acetyl spermine (NAS, a specific Ca2+-permeable AMPA receptor blocker). Lead exposure activated extracellular signal-regulated protein kinase (ERK) 1/2, which was significantly ameliorated by CNQX. In addition, lead exposure activated p38 mitogen-activated protein kinase (MAPK p38), and protein kinase C (PKC), which was partially ameliorated by CNQX. Our findings indicate that Ca2+-permeable AMPA receptors resulting from GluR2 decrease may be involved in lead-induced neurotoxicity.
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Affiliation(s)
- Keishi Ishida
- Graduate School of Biomedical and Health Sciences, Hiroshima University
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9
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Miyara M, Kotake Y, Tokunaga W, Sanoh S, Ohta S. Mild MPP + exposure impairs autophagic degradation through a novel lysosomal acidity-independent mechanism. J Neurochem 2016; 139:294-308. [PMID: 27309572 DOI: 10.1111/jnc.13700] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/25/2016] [Accepted: 06/07/2016] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disorder, but its underlying cause remains unknown. Although recent studies using PD-related neurotoxin MPP+ suggest autophagy involvement in the pathogenesis of PD, the effect of MPP+ on autophagic processes under mild exposure, which mimics the slow progressive nature of PD, remains largely unclear. We examined the effect of mild MPP+ exposure (10 and 200 μM for 48 h), which induces a more slowly developing cell death, on autophagic processes and the mechanistic differences with acute MPP+ toxicity (2.5 and 5 mM for 24 h). In SH-SY5Y cells, mild MPP+ exposure predominantly inhibited autophagosome degradation, whereas acute MPP+ exposure inhibited both autophagosome degradation and basal autophagy. Mild MPP+ exposure reduced lysosomal hydrolase cathepsin D activity without changing lysosomal acidity, whereas acute exposure decreased lysosomal density. Lysosome biogenesis enhancers trehalose and rapamycin partially alleviated mild MPP+ exposure induced impaired autophagosome degradation and cell death, but did not prevent the pathogenic response to acute MPP+ exposure, suggesting irreversible lysosomal damage. We demonstrated impaired autophagic degradation by MPP+ exposure and mechanistic differences between mild and acute MPP+ toxicities. Mild MPP+ toxicity impaired autophagosome degradation through novel lysosomal acidity-independent mechanisms. Sustained mild lysosomal damage may contribute to PD. We examined the effects of MPP+ on autophagic processes under mild exposure, which mimics the slow progressive nature of Parkinson's disease, in SH-SY5Y cells. This study demonstrated impaired autophagic degradation through a reduction in lysosomal cathepsin D activity without altering lysosomal acidity by mild MPP+ exposure. Mechanistic differences between acute and mild MPP+ toxicity were also observed. Sustained mild damage of lysosome may be an underlying cause of Parkinson's disease. Cover Image for this issue: doi: 10.1111/jnc.13338.
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Affiliation(s)
- Masatsugu Miyara
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.,Global Career Design Center, Hiroshima University, Hiroshima, Japan
| | - Yaichiro Kotake
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
| | - Wataru Tokunaga
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Seigo Sanoh
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Shigeru Ohta
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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10
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Memantine, a Low-Affinity NMDA Receptor Antagonist, Protects against Methylmercury-Induced Cytotoxicity of Rat Primary Cultured Cortical Neurons, Involvement of Ca2+ Dyshomeostasis Antagonism, and Indirect Antioxidation Effects. Mol Neurobiol 2016; 54:5034-5050. [DOI: 10.1007/s12035-016-0020-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 08/01/2016] [Indexed: 01/20/2023]
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11
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Perfluorooctane sulfonate induces neuronal vulnerability by decreasing GluR2 expression. Arch Toxicol 2016; 91:885-895. [PMID: 27155986 DOI: 10.1007/s00204-016-1731-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/27/2016] [Indexed: 10/21/2022]
Abstract
Perfluorooctane sulfonate (PFOS) is a persistent environmental contaminant. Although studies have described PFOS-induced neurotoxicity in animal brains and neuronal cells, the molecular mechanisms of PFOS-induced neurotoxicity based on the distribution properties, especially during developmental periods, have not been clarified. To clarify the mechanisms of PFOS-induced neuronal vulnerability during developmental periods, we examined changes in glutamate receptor 2 (GluR2) expression and related neurotoxicity in PFOS-treated primary cortical neurons and neonatal rat brains. Exposure of cortical neurons to 1 μM PFOS for 9 days resulted in decreased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluR2 expression, which subsequently enhanced vulnerability to glutamate by increasing intracellular Ca2+ concentrations. The brain-plasma ratio of PFOS in pups was approximately five times higher than that in dams, although there were no differences in liver-plasma ratio between dams and pups. GluR2 expression in pup cerebral cortex decreased after exposure to 2.0 mg/kg PFOS, and kainic acid induced histopathological abnormalities in PFOS-exposed pups. Our findings suggest that decreased neuronal GluR2 expression is involved in PFOS-induced neurotoxicity, especially during the fetal and neonatal periods.
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12
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Umeda K, Kotake Y, Miyara M, Ishida K, Sanoh S, Ohta S. Methoxychlor and fenvalerate induce neuronal death by reducing GluR2 expression. J Toxicol Sci 2016; 41:255-64. [DOI: 10.2131/jts.41.255] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Kanae Umeda
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Yaichiro Kotake
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Masatsugu Miyara
- Graduate School of Biomedical and Health Sciences, Hiroshima University
- Research Fellow of the Japan Society for the Promotion of Science
| | - Keishi Ishida
- Graduate School of Biomedical and Health Sciences, Hiroshima University
- Research Fellow of the Japan Society for the Promotion of Science
| | - Seigo Sanoh
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Shigeru Ohta
- Graduate School of Biomedical and Health Sciences, Hiroshima University
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13
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Sugiyama C, Kotake Y, Yamaguchi M, Umeda K, Tsuyama Y, Sanoh S, Okuda K, Ohta S. Development of a simple measurement method for GluR2 protein expression as an index of neuronal vulnerability. Toxicol Rep 2015; 2:450-460. [PMID: 28962381 PMCID: PMC5598506 DOI: 10.1016/j.toxrep.2014.12.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 12/20/2014] [Accepted: 12/20/2014] [Indexed: 11/28/2022] Open
Abstract
In vitro estimating strategies for potential neurotoxicity are required to screen multiple substances. In a previous study, we showed that exposure to low-concentrations of some chemicals, such as organotin, decreased the expression of GluR2 protein, which is a subunit of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type glutamate receptors, and led to neuronal vulnerability. This result suggested that GluR2 decreases as an index of neuronal cell sensitivity and vulnerability to various toxic insults. Accordingly, we developed a versatile method that is a large scale determination of GluR2 protein expression in the presence of environmental chemicals by means of AlphaLISA technology. Various analytical conditions were optimized, and then GluR2 protein amount was measured by the method using AlphaLISA. The GluR2 amounts were strongly correlated with that of measured by western blotting, which is currently used to determine GluR2 expression. An ideal standard curve could be written with the authentic GluR2 protein from 0 ng to 100 ng. Subsequently, twenty environmental chemicals were screened and nitenpyram was identified as a chemical which lead to decrease in GluR2 protein expression. This assay may provide a tool for detecting neurotoxic chemicals according to decreases in GluR2 protein expression.
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Key Words
- AMPA receptor
- AMPA receptor, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor
- AlphaLISA
- Cell-based assay
- DMEM, Dulbecco's modified Eagle's medium
- DMSO, dimethyl sulfoxide
- EDTA, ethylenediaminetetraacetic acid
- FCS, fetal calf serum
- Glu, glutamate
- GluR2
- HS, horse serum
- MAP2, microtubule-associated protein 2
- NAS, 1-naphthylacetylspermine
- Neurotoxicity
- Nitenpyram
- PBS, phosphate-buffered saline
- TBT, tributyltin
- WST-1, 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium
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Affiliation(s)
- Chihiro Sugiyama
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Yaichiro Kotake
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Masafumi Yamaguchi
- Faculty of Pharmaceutical Sciences, Hiroshima International University, 5-1-1 Hirokoshinkai, Kure, Hiroshima 737-0112, Japan
| | - Kanae Umeda
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Yumi Tsuyama
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Seigo Sanoh
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Katsuhiro Okuda
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Shigeru Ohta
- Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan
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14
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Ekinci M, Ceylan E, Çağatay HH, Keleş S, Altınkaynak H, Kartal B, Koban Y, Hüseyinoğlu N. Occupational Exposure to Lead Decreases Macular, Choroidal, and Retinal Nerve Fiber Layer Thickness in Industrial Battery Workers. Curr Eye Res 2014; 39:853-8. [DOI: 10.3109/02713683.2013.877934] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Kotake Y, Sekiya Y, Okuda K, Ohta S. Detection of a novel neurotoxic metabolite of Parkinson’s disease-related neurotoxin, 1-benzyl-1,2,3,4- tetrahydroisoquinoline. J Toxicol Sci 2014; 39:749-54. [DOI: 10.2131/jts.39.749] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Yaichiro Kotake
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Yoko Sekiya
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Katsuhiro Okuda
- Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Shigeru Ohta
- Graduate School of Biomedical and Health Sciences, Hiroshima University
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