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Fujimura M, Unoki T. BDNF specifically expressed in hippocampal neurons is involved in methylmercury neurotoxicity resistance. ENVIRONMENTAL TOXICOLOGY 2024; 39:3149-3159. [PMID: 38323385 DOI: 10.1002/tox.24174] [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: 12/03/2023] [Revised: 01/10/2024] [Accepted: 01/17/2024] [Indexed: 02/08/2024]
Abstract
Methylmercury (MeHg) causes selective neuronal damage to cerebrocortical neurons (CCNs) in the central nervous system, but not to hippocampal neurons (HiNs), which are highly vulnerable to neurodegenerative diseases. In our previous study using cultured rat neurons, we performed a comprehensive gene expression analysis and found that the brain-derived neurotrophic factor (BDNF), a neurotrophin (NT), was specifically expressed in HiNs. Therefore, to elucidate the causal factors of MeHg toxicity resistance in HiNs, we conducted a comparative study of the protein expression and function of several NTs, including BDNF, using CCNs showing vulnerability to MeHg toxicity and HiNs showing resistance. BDNF was specifically expressed in HiNs, whereas nerve growth factor was barely detectable in either neuron type. In addition, other NTs, NT3 and NT4/5, were expressed in small but nearly equal amounts in both neuron types. Furthermore, among the various pathways involved in MeHg neurotoxicity, the p44/42 MAPK pathway was specifically activated in HiNs, even without MeHg treatment. siRNAs were used to reduce NTs in both neuron types. Only a specific reduction in BDNF attenuated the resistance to MeHg toxicity and p44/42 MAPK activation in HiNs. In addition, the external addition of BDNF and NT4/5, which act on the same tyrosine receptor kinase (Trk), TrkB, suppressed MeHg neurotoxicity in both neuron types. These results suggest that BDNF, expressed specifically in HiNs, is involved in the resistance to MeHg neurotoxicity via TrkB. Additionally, the activation of the p44/42 MAPK pathway may contribute to the inhibitory effect of BDNF on MeHg neurotoxicity.
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Affiliation(s)
- Masatake Fujimura
- Department of Basic Medical Science, National Institute for Minamata Disease, Kumamoto, Japan
| | - Takamitsu Unoki
- Department of Basic Medical Science, National Institute for Minamata Disease, Kumamoto, Japan
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2
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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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3
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de Paula Arrifano G, Crespo-Lopez ME, Lopes-Araújo A, Santos-Sacramento L, Barthelemy JL, de Nazaré CGL, Freitas LGR, Augusto-Oliveira M. Neurotoxicity and the Global Worst Pollutants: Astroglial Involvement in Arsenic, Lead, and Mercury Intoxication. Neurochem Res 2023; 48:1047-1065. [PMID: 35997862 DOI: 10.1007/s11064-022-03725-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/01/2022] [Accepted: 08/09/2022] [Indexed: 10/15/2022]
Abstract
Environmental pollution is a global threat and represents a strong risk factor for human health. It is estimated that pollution causes about 9 million premature deaths every year. Pollutants that can cross the blood-brain barrier and reach the central nervous system are of special concern, because of their potential to cause neurological and development disorders. Arsenic, lead and mercury are usually ranked as the top three in priority lists of regulatory agencies. Against xenobiotics, astrocytes are recognised as the first line of defence in the CNS, being involved in virtually all brain functions, contributing to homeostasis maintenance. Here, we discuss the current knowledge on the astroglial involvement in the neurotoxicity induced by these pollutants. Beginning by the main toxicokinetic characteristics, this review also highlights the several astrocytic mechanisms affected by these pollutants, involving redox system, neurotransmitter and glucose metabolism, and cytokine production/release, among others. Understanding how these alterations lead to neurological disturbances (including impaired memory, deficits in executive functions, and motor and visual disfunctions), by revisiting the current knowledge is essential for future research and development of therapies and prevention strategies.
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Affiliation(s)
- Gabriela de Paula Arrifano
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA, 66075-110, Brazil
| | - Maria Elena Crespo-Lopez
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA, 66075-110, Brazil
| | - Amanda Lopes-Araújo
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA, 66075-110, Brazil
| | - Letícia Santos-Sacramento
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA, 66075-110, Brazil
| | - Jean L Barthelemy
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA, 66075-110, Brazil
| | - Caio Gustavo Leal de Nazaré
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA, 66075-110, Brazil
| | - Luiz Gustavo R Freitas
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA, 66075-110, Brazil
| | - Marcus Augusto-Oliveira
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA, 66075-110, Brazil.
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4
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Fujikawa A, Ishihara Y, Ohta E, Nehira T, Ômura H, Uy MM, Ohta S. Isolation of Fluorescent Benzoxazines with Neuroprotective Activity from the Olive Weevil Pimelocerus perforatus. JOURNAL OF NATURAL PRODUCTS 2022; 85:2740-2745. [PMID: 36269877 DOI: 10.1021/acs.jnatprod.2c00670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The weevil Pimelocerus perforatus poses a serious pest problem for olive cultivation in Japan. Two new racemic fluorescent benzoxazines, designated as pimeforazine A ((±)-1) and pimeforazine B ((±)-2), were successfully isolated from P. perforatus. Their structures, including the absolute configurations of their resolved enantiomers, were determined using spectroscopic methods, single-crystal X-ray diffraction, and electronic circular dichroism calculations. The neuroprotective activity of the isolated compounds was evaluated against hydrogen peroxide-induced cellular damage in SH-SY5Y human neuroblastoma cells. Compounds (±)-1 and (±)-2 exhibited neuroprotective effects.
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Affiliation(s)
- Aya Fujikawa
- School of Applied Biological Science, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Yasuhiro Ishihara
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Emi Ohta
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Tatsuo Nehira
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Hisashi Ômura
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Mylene M Uy
- Department of Chemistry, Mindanao State University-Iligan Institute of Technology, Iligan City9200, Philippines
| | - Shinji Ohta
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
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Borgonetti V, Biagi M, Galeotti N, Manetti F, Governa P. Investigation on the neuroprotective effect of a cannabidiol-enriched non-psychotropic Cannabis sativa L. extract in an in vitro model of excitotoxicity. Fitoterapia 2022; 163:105315. [PMID: 36179898 DOI: 10.1016/j.fitote.2022.105315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 09/19/2022] [Accepted: 09/23/2022] [Indexed: 11/04/2022]
Abstract
The purpose of this study was to evaluate the neuroprotective effect of a cannabidiol-enriched non-psychotropic Cannabis sativa L. extract (CSE) and its main constituents, cannabidiol and β-caryophyllene. An in vitro model of glutamate-induced neuronal excitotoxicity using SH-SY5Y cells was optimized. The impact of CSE on glutamate-impaired cell viability, brain-derived neurotrophic factor release, CB1 protein expression, and ERK levels was evaluated. The involvement of CB1 modulation was verified by the cotreatment with the CB1 antagonist AM4113. CSE was able to significantly protect SH-SY5Y from glutamate-impaired cell viability, and to counteract the changes in brain-derived neurotrophic factor levels, with a mechanism of action involving ERK modulation. Moreover, CSE completely reversed the reduction of CB1 receptor expression induced by glutamate, and the presence of the CB1 antagonist AM4113 reduced CSE effectiveness, suggesting that CBr play a role in the modulation of neuronal excitotoxicity. This work demonstrated the in vitro effectiveness of CSE as a neuroprotective agent, proposing the whole cannabis phytocomplex as a more effective strategy, compared to its main constituents alone, and suggested further investigations by using more complex cell models before moving to in vivo studies.
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Affiliation(s)
- Vittoria Borgonetti
- Department of Neuroscience, Psychology, Pharmacology and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Marco Biagi
- Department of Physical Sciences, Earth and Environment, University of Siena, Siena, Italy
| | - Nicoletta Galeotti
- Department of Neuroscience, Psychology, Pharmacology and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Fabrizio Manetti
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, Siena, Italy
| | - Paolo Governa
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, Siena, Italy.
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Ohta S, Takeda M, Ohta E, Nehira T, Ômura H, Uy MM, Ishihara Y. Janohigenins: Long-chain anacardic acid derivatives with neuroprotective activity from Ophiopogon japonicus seeds. PHYTOCHEMISTRY 2021; 191:112904. [PMID: 34388665 DOI: 10.1016/j.phytochem.2021.112904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 07/24/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
Eight hitherto undescribed long-chain anacardic acid derivatives, janohigenins, were isolated from the endosperm of Ophiopogon japonicus seed, and their structures were elucidated employing spectroscopic and chemical methods. The neuroprotective activity of the isolated compounds was evaluated against rotenone-induced cellular damage in SH-SY5Y human neuroblastoma cells. Janohigenins exhibited noticeable neuroprotection at 1 μM.
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Affiliation(s)
- Shinji Ohta
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, 739-8521, Japan.
| | - Manami Takeda
- Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, 739-8521, Japan
| | - Emi Ohta
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, 739-8521, Japan
| | - Tatsuo Nehira
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, 739-8521, Japan
| | - Hisashi Ômura
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, 739-8521, Japan
| | - Mylene M Uy
- Department of Chemistry, Mindanao State University-Iligan Institute of Technology, Iligan City, 9200, Philippines
| | - Yasuhiro Ishihara
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, 739-8521, Japan.
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7
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Pistollato F, Carpi D, Mendoza-de Gyves E, Paini A, Bopp SK, Worth A, Bal-Price A. Combining in vitro assays and mathematical modelling to study developmental neurotoxicity induced by chemical mixtures. Reprod Toxicol 2021; 105:101-119. [PMID: 34455033 PMCID: PMC8522961 DOI: 10.1016/j.reprotox.2021.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 07/30/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022]
Abstract
Prenatal and postnatal co-exposure to multiple chemicals at the same time may have deleterious effects on the developing nervous system. We previously showed that chemicals acting through similar mode of action (MoA) and grouped based on perturbation of brain derived neurotrophic factor (BDNF), induced greater neurotoxic effects on human induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes compared to chemicals with dissimilar MoA. Here we assessed the effects of repeated dose (14 days) treatments with mixtures containing the six chemicals tested in our previous study (Bisphenol A, Chlorpyrifos, Lead(II) chloride, Methylmercury chloride, PCB138 and Valproic acid) along with 2,2'4,4'-tetrabromodiphenyl ether (BDE47), Ethanol, Vinclozolin and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)), on hiPSC-derived neural stem cells undergoing differentiation toward mixed neurons/astrocytes up to 21 days. Similar MoA chemicals in mixtures caused an increase of BDNF levels and neurite outgrowth, and a decrease of synapse formation, which led to inhibition of electrical activity. Perturbations of these endpoints are described as common key events in adverse outcome pathways (AOPs) specific for DNT. When compared with mixtures tested in our previous study, adding similarly acting chemicals (BDE47 and EtOH) to the mixture resulted in a stronger downregulation of synapses. A synergistic effect on some synaptogenesis-related features (PSD95 in particular) was hypothesized upon treatment with tested mixtures, as indicated by mathematical modelling. Our findings confirm that the use of human iPSC-derived mixed neuronal/glial models applied to a battery of in vitro assays anchored to key events in DNT AOP networks, combined with mathematical modelling, is a suitable testing strategy to assess in vitro DNT induced by chemical mixtures.
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Affiliation(s)
| | - Donatella Carpi
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | - Alicia Paini
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | - Andrew Worth
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy.
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Tukker AM, Westerink RHS. Novel test strategies for in vitro seizure liability assessment. Expert Opin Drug Metab Toxicol 2021; 17:923-936. [PMID: 33595380 PMCID: PMC8367052 DOI: 10.1080/17425255.2021.1876026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/11/2021] [Indexed: 12/18/2022]
Abstract
INTRODUCTION The increasing incidence of mental illnesses and neurodegenerative diseases results in a high demand for drugs targeting the central nervous system (CNS). These drugs easily reach the CNS, have a high affinity for CNS targets, and are prone to cause seizures as an adverse drug reaction. Current seizure liability assessment heavily depends on in vivo or ex vivo animal models and is therefore ethically debated, labor intensive, expensive, and not always predictive for human risk. AREAS COVERED The demand for CNS drugs urges the development of alternative safety assessment strategies. Yet, the complexity of the CNS hampers reliable detection of compound-induced seizures. This review provides an overview of the requirements of in vitro seizure liability assays and highlights recent advances, including micro-electrode array (MEA) recordings using rodent and human cell models. EXPERT OPINION Successful and cost-effective replacement of in vivo and ex vivo models for seizure liability screening can reduce animal use for drug development, while increasing the predictive value of the assays, particularly if human cell models are used. However, these novel test strategies require further validation and standardization as well as additional refinements to better mimic the human in vivo situation and increase their predictive value.
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Affiliation(s)
- Anke M. Tukker
- School of Health Sciences, Purdue University, Hall for Discovery and Learning Research (DLR 339), INUSA
| | - Remco H. S. Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, TD Utrecht, The Netherlands
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Revisiting Astrocytic Roles in Methylmercury Intoxication. Mol Neurobiol 2021; 58:4293-4308. [PMID: 33990914 DOI: 10.1007/s12035-021-02420-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 05/04/2021] [Indexed: 02/06/2023]
Abstract
Intoxication by heavy metals such as methylmercury (MeHg) is recognized as a global health problem, with strong implications in central nervous system pathologies. Most of these neuropathological conditions involve vascular, neurotransmitter recycling, and oxidative balance disruption leading to accelerated decline in fine balance, and learning, memory, and visual processes as main outcomes. Besides neurons, astrocytes are involved in virtually all the brain processes and perform important roles in neurological response following injuries. Due to astrocytes' strategic functions in brain homeostasis, these cells became the subject of several studies on MeHg intoxication. The most heterogenous glial cells, astrocytes, are composed of plenty of receptors and transporters to dialogue with neurons and other cells and to monitor extracellular environment responding tightly through fluctuation of cytosolic ions. The overall toxicity of MeHg might be determined on the basis of the balance between MeHg-mediated injury to neurons and protective responses from astrocytes. Although the role of neurons in MeHg intoxication is relatively well-established, the role of the astrocytes is only beginning to be understood. In this review, we update the information on astroglial modulation of the MeHg-induced neurotoxicity, providing remarks on their protective and deleterious roles and insights for future studies.
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Ohta S, Oshimo S, Ohta E, Nehira T, Ômura H, Uy MM, Ishihara Y. Asaroidoxazines from the Roots of Asarum asaroides Induce Apoptosis in Human Neuroblastoma Cells. JOURNAL OF NATURAL PRODUCTS 2020; 83:3050-3057. [PMID: 32955260 DOI: 10.1021/acs.jnatprod.0c00574] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Plants in the family Aristolochiaceae contain phenanthrene skeleton-containing chemical constituents that exhibit nephrotoxic, carcinogenic, mutagenic, anti-inflammatory, and cytotoxic effects. Two new phenanthrene-containing 1,2-oxazin-6-ones, designated as asaroidoxazine A (1) and asaroidoxazine B (2), and a known aristolactam, 5-methoxyaristololactam I (3), were isolated from the roots of Asarum asaroides. The structures of compounds 1 and 2 were determined using spectroscopic methods and X-ray crystallography. Treatment of SH-SY5Y human neuroblastoma cells with 1 μM of asaroidoxazine A (1) induced nuclear condensation as well as caspase-3/7 activation, indicating that this compound is a strong apoptosis inducer in neuronal cells. This is the first report of apoptosis induction by phenanthrene-containing oxazines.
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Affiliation(s)
- Shinji Ohta
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Shiori Oshimo
- Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Emi Ohta
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Tatsuo Nehira
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Hisashi Ômura
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Mylene M Uy
- Department of Chemistry, Mindanao State University-Iligan Institute of Technology, Iligan City 9200, Philippines
| | - Yasuhiro Ishihara
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
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11
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Fujimura M, Usuki F, Unoki T. Decreased plasma thiol antioxidant capacity precedes neurological signs in a rat methylmercury intoxication model. Food Chem Toxicol 2020; 146:111810. [PMID: 33058990 DOI: 10.1016/j.fct.2020.111810] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/13/2022]
Abstract
The main target organ for MeHg is the nervous system, and its neurological dysfunction remains irreversible. Therefore, predictive biomarkers associated with individual susceptibility to MeHg and future clinical severity are needed to protect against the progression of MeHg toxicity. In this study, we demonstrated that plasma thiol antioxidant capacity (-SHp) is a useful predictive biomarker associated with future clinical severity using MeHg-intoxicated rats administered 1 mg/kg/day for 4 weeks. Blood samples were collected from the subclavian vein of each rat once a week to examine total blood mercury concentrations and the levels of plasma oxidative stress markers. Time course analyses of the correlation between these weekly blood examination values and hind limb crossing signs score after 4 weeks of MeHg exposure were performed, and plasma -SHp levels after 2 weeks of MeHg exposure showed strong correlations with future hind limb crossing sign scores. Neuropathological changes also developed in parallel with hind limb crossing sign scores. Quantitative analysis of vacuolar areas in the spinal cord showed a strong correlation with hind limb crossing sign scores. In conclusion, evaluation of plasma -SHp levels allowed us to detect individuals at risk for health damage and could protect the sensitive population against MeHg toxicity.
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Affiliation(s)
- Masatake Fujimura
- Department of Basic Medical Science, National Institute for Minamata Disease, Kumamoto, Japan.
| | - Fusako Usuki
- Division of Neuroimmunology, Joint Research Center for Human Retrovirus Infection, Kagoshima University, Kagoshima, Japan
| | - Takamitsu Unoki
- Department of Basic Medical Science, National Institute for Minamata Disease, Kumamoto, Japan
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12
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Freire MAM, Lima RR, Nascimento PC, Gomes-Leal W, Pereira A. Effects of methylmercury on the pattern of NADPH diaphorase expression and astrocytic activation in the rat. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 201:110799. [PMID: 32544743 DOI: 10.1016/j.ecoenv.2020.110799] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/18/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
Mercury (Hg) is an environmental contaminant that poses great risk to human health. However, it is still widely used in artisanal gold-mining enterprises around the world, especially in developing countries. Methylmercury (MeHg) is produced environmentally by biomethylation of inorganic Hg present in water sediments, leading to its subsequent accumulation in the aquatic food chain. Due to its high metabolic rate, the Central Nervous System (CNS) is one of the main targets of MeHg. In the present study, we investigate the impact of chronic MeHg intoxication on NADPH diaphorase (NADPH-d) activity and astrocyte mobilization in the visual cortex of the rat. After 60 days of MeHg administration by oral gavage (0.04 mg/kg/day), tissue samples containing the visual cortex were submitted to measurements of Hg levels, NADPH-d activity, and GFAP immunohistochemistry for identification of astrocytes. MeHg intoxication was associated with increased Hg deposits and with reduced NADPH-d neuropil reactivity in the visual cortex. A morphometric analysis suggested that NADPH-d-positive neurons were mostly spared from MeHg harmful action and intoxicated animals had astrocytic activation similar to the control group. The decrease in NADPH-d neuropil reactivity may be due to the negative effect of chronic MeHg poisoning on both the synthesis and transport of this enzyme in afferent pathways to the visual cortex. The relative resistance of NADPH-d-reactive neurons to chronic MeHg intoxication may be associated with peculiarities in cell metabolism or to a protective role of nitric oxide, safeguarding those neurons from Hg deleterious effects.
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Affiliation(s)
- Marco Aurelio M Freire
- Graduate Program in Health and Society, Faculty of Health Sciences, University of State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém, PA, Brazil
| | - Priscila Cunha Nascimento
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém, PA, Brazil
| | - Walace Gomes-Leal
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém, PA, Brazil
| | - Antonio Pereira
- Department of Electrical and Biomedical Engineering, Institute of Technology, Federal University of Pará (UFPA), Belém, PA, Brazil.
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13
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An efficient neuron-astrocyte differentiation protocol from human embryonic stem cell-derived neural progenitors to assess chemical-induced developmental neurotoxicity. Reprod Toxicol 2020; 98:107-116. [PMID: 32931842 DOI: 10.1016/j.reprotox.2020.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/13/2020] [Accepted: 09/07/2020] [Indexed: 01/10/2023]
Abstract
Human embryonic stem cell neuronal differentiation models provide promising in vitro tools for the prediction of developmental neurotoxicity of chemicals. Such models mimic essential elements of human relevant neuronal development, including the differentiation of a variety of brain cell types and their neuronal network formation as evidenced by specific gene and protein biomarkers. However, the reproducibility and lengthy culture duration of cell models present drawbacks and delay regulatory implementation. Here we present a relatively short and robust protocol to differentiate H9-derived neural progenitor cells (NPCs) into a neuron-astrocyte co-culture. When frozen-stored NPCs were re-cultured and induced into neuron-astrocyte differentiation, they showed gene- and protein expression typical for these cells, and most notably they exhibited spontaneous electrical activity within three days of culture as measured by a multi-well micro-electrode array. Modulating the ratio of astrocytes and neurons through different growth factors including glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) did not compromise the ability to develop spontaneous electrical activity. This robust neuronal differentiation model may serve as a functional component of a testing strategy for unravelling mechanisms of developmental neurotoxicity.
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14
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Yang L, Zhang Y, Wang F, Luo Z, Guo S, Strähle U. Toxicity of mercury: Molecular evidence. CHEMOSPHERE 2020; 245:125586. [PMID: 31881386 DOI: 10.1016/j.chemosphere.2019.125586] [Citation(s) in RCA: 161] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/28/2019] [Accepted: 12/08/2019] [Indexed: 05/25/2023]
Abstract
Minamata disease in Japan and the large-scale poisoning by methylmercury (MeHg) in Iraq caused wide public concerns about the risk emanating from mercury for human health. Nowadays, it is widely known that all forms of mercury induce toxic effects in mammals, and increasing evidence supports the concern that environmentally relevant levels of MeHg could impact normal biological functions in wildlife. The information of mechanism involved in mercurial toxicity is growing but knowledge gaps still exist between the adverse effects and mechanisms of action, especially at the molecular level. A body of data obtained from experimental studies on mechanisms of mercurial toxicity in vivo and in vitro points to that disruption of the antioxidant system may play an important role in the mercurial toxic effects. Moreover, the accumulating evidence indicates that signaling transduction, protein or/and enzyme activity, and gene regulation are involving in mediating toxic and adaptive response to mercury exposure. We conducted here a comprehensive review of mercurial toxic effects on wildlife and human, in particular synthesized key findings of molecular pathways involved in mercurial toxicity from the cells to human. We discuss the molecular evidence related mercurial toxicity to the adverse effects, with particular emphasis on the gene regulation. The further studies relying on Omic analysis connected to adverse effects and modes of action of mercury will aid in the evaluation and validation of causative relationship between health outcomes and gene expression.
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Affiliation(s)
- Lixin Yang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China; Center for Global Health, School of Public Health, Nanjing Medical University, 211166, Nanjing, China.
| | - Yuanyuan Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Feifei Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Zidie Luo
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Shaojuan Guo
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Uwe Strähle
- Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
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15
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Pistollato F, de Gyves EM, Carpi D, Bopp SK, Nunes C, Worth A, Bal-Price A. Assessment of developmental neurotoxicity induced by chemical mixtures using an adverse outcome pathway concept. Environ Health 2020; 19:23. [PMID: 32093744 PMCID: PMC7038628 DOI: 10.1186/s12940-020-00578-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/11/2020] [Indexed: 05/25/2023]
Abstract
BACKGROUND In light of the vulnerability of the developing brain, mixture risk assessment (MRA) for the evaluation of developmental neurotoxicity (DNT) should be implemented, since infants and children are co-exposed to more than one chemical at a time. One possible approach to tackle MRA could be to cluster DNT chemicals in a mixture on the basis of their mode of action (MoA) into 'similar' and 'dissimilar', but still contributing to the same adverse outcome, and anchor DNT assays to common key events (CKEs) identified in DNT-specific adverse outcome pathways (AOPs). Moreover, the use of human in vitro models, such as induced pluripotent stem cell (hiPSC)-derived neuronal and glial cultures would enable mechanistic understanding of chemically-induced adverse effects, avoiding species extrapolation. METHODS HiPSC-derived neural progenitors differentiated into mixed cultures of neurons and astrocytes were used to assess the effects of acute (3 days) and repeated dose (14 days) treatments with single chemicals and in mixtures belonging to different classes (i.e., lead(II) chloride and methylmercury chloride (heavy metals), chlorpyrifos (pesticide), bisphenol A (organic compound and endocrine disrupter), valproic acid (drug), and PCB138 (persistent organic pollutant and endocrine disrupter), which are associated with cognitive deficits, including learning and memory impairment in children. Selected chemicals were grouped based on their mode of action (MoA) into 'similar' and 'dissimilar' MoA compounds and their effects on synaptogenesis, neurite outgrowth, and brain derived neurotrophic factor (BDNF) protein levels, identified as CKEs in currently available AOPs relevant to DNT, were evaluated by immunocytochemistry and high content imaging analysis. RESULTS Chemicals working through similar MoA (i.e., alterations of BDNF levels), at non-cytotoxic (IC20/100), very low toxic (IC5), or moderately toxic (IC20) concentrations, induce DNT effects in mixtures, as shown by increased number of neurons, impairment of neurite outgrowth and synaptogenesis (the most sensitive endpoint as confirmed by mathematical modelling) and increase of BDNF levels, to a certain extent reproducing autism-like cellular changes observed in the brain of autistic children. CONCLUSIONS Our findings suggest that the use of human iPSC-derived mixed neuronal/glial cultures applied to a battery of assays anchored to key events of an AOP network represents a valuable approach to identify mixtures of chemicals with potential to cause learning and memory impairment in children.
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Affiliation(s)
| | | | - Donatella Carpi
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | - Carolina Nunes
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Andrew Worth
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy
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16
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Lipopolysaccharide-Induced Matrix Metalloproteinase-9 Expression Associated with Cell Migration in Rat Brain Astrocytes. Int J Mol Sci 2019; 21:ijms21010259. [PMID: 31905967 PMCID: PMC6982104 DOI: 10.3390/ijms21010259] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/25/2019] [Accepted: 12/27/2019] [Indexed: 12/17/2022] Open
Abstract
Neuroinflammation is a landmark of neuroinflammatory and neurodegenerative diseases. Matrix metalloproteinase (MMP)-9, one member of MMPs, has been shown to contribute to the pathology of these brain diseases. Several experimental models have demonstrated that lipopolysaccharide (LPS) exerts a pathological role through Toll-like receptors (TLRs) in neuroinflammation and neurodegeneration. However, the mechanisms underlying LPS-induced MMP-9 expression in rat brain astrocytes (RBA-1) are not completely understood. Here, we applied pharmacological inhibitors and siRNA transfection to assess the levels of MMP-9 protein, mRNA, and promoter activity, as well as protein kinase phosphorylation in RBA-1 cells triggered by LPS. We found that LPS-induced expression of pro-form MMP-9 and cell migration were mediated through TLR4, proto-oncogene tyrosine-protein kinase (c-Src), proline-rich tyrosine kinase 2 (Pyk2), platelet-derived growth factor receptor (PDGFR), phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), p38 mitogen-activated protein kinase (MAPK), and Jun amino-terminal kinase (JNK)1/2 signaling molecules in RBA-1 cells. In addition, LPS-stimulated binding of c-Jun to the MMP-9 promoter was confirmed by chromatin immunoprecipitation (ChIP) assay, which was blocked by pretreatment with c-Src inhibitor II, PF431396, AG1296, LY294002, Akt inhibitor VIII, p38 MAP kinase inhibitor VIII, SP600125, and tanshinone IIA. These results suggest that in RBA-1 cells, LPS activates a TLR4/c-Src/Pyk2/PDGFR/PI3K/Akt/p38 MAPK and JNK1/2 pathway, which in turn triggers activator protein 1 (AP-1) activation and ultimately induces MMP-9 expression and cell migration.
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17
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Ishihara Y, Itoh K, Oguro A, Chiba Y, Ueno M, Tsuji M, Vogel CFA, Yamazaki T. Neuroprotective activation of astrocytes by methylmercury exposure in the inferior colliculus. Sci Rep 2019; 9:13899. [PMID: 31554907 PMCID: PMC6761145 DOI: 10.1038/s41598-019-50377-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/11/2019] [Indexed: 11/17/2022] Open
Abstract
Methylmercury (MeHg) is well known to induce auditory disorders such as dysarthria. When we performed a global analysis on the brains of mice exposed to MeHg by magnetic resonance imaging, an increase in the T1 signal in the inferior colliculus (IC), which is localized in the auditory pathway, was observed. Therefore, the purpose of this study is to examine the pathophysiology and auditory dysfunction induced by MeHg, focusing on the IC. Measurement of the auditory brainstem response revealed increases in latency and decreases in threshold in the IC of mice exposed to MeHg for 4 weeks compared with vehicle mice. Incoordination in MeHg-exposed mice was noted after 6 weeks of exposure, indicating that IC dysfunction occurs earlier than incoordination. There was no change in the number of neurons or microglial activity, while the expression of glial fibrillary acidic protein, a marker for astrocytic activity, was elevated in the IC of MeHg-exposed mice after 4 weeks of exposure, indicating that astrogliosis occurs in the IC. Suppression of astrogliosis by treatment with fluorocitrate exacerbated the latency and threshold in the IC evaluated by the auditory brainstem response. Therefore, astrocytes in the IC are considered to play a protective role in the auditory pathway. Astrocytes exposed to MeHg increased the expression of brain-derived neurotrophic factor in the IC, suggesting that astrocytic brain-derived neurotrophic factor is a potent protectant in the IC. This study showed that astrogliosis in the IC could be an adaptive response to MeHg toxicity. The overall toxicity of MeHg might be determined on the basis of the balance between MeHg-mediated injury to neurons and protective responses from astrocytes.
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Affiliation(s)
- Yasuhiro Ishihara
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8521, Japan. .,Center for Health and the Environment, University of California, Davis, CA, 95616, USA.
| | - Kouichi Itoh
- Laboratory for Pharmacotherapy and Experimental Neurology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa, 769-2193, Japan
| | - Ami Oguro
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8521, Japan
| | - Yoichi Chiba
- Department of Pathology and Host Defense, Faculty of Medicine, Kagawa University, Kagawa, 761-0793, Japan
| | - Masaki Ueno
- Department of Pathology and Host Defense, Faculty of Medicine, Kagawa University, Kagawa, 761-0793, Japan
| | - Mayumi Tsuji
- Department of Environmental Health, University of Occupational and Environmental Health, Fukuoka, 807-8555, Japan
| | - Christoph F A Vogel
- Center for Health and the Environment, University of California, Davis, CA, 95616, USA.,Department of Environmental Toxicology, University of California, Davis, CA, 95616, USA
| | - Takeshi Yamazaki
- Program of Life and Environmental Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8521, Japan
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18
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David J, O'Toole E, O'Reilly K, Thuery G, Assmann N, Finlay D, Harkin A. Inhibitors of the NMDA-Nitric Oxide Signaling Pathway Protect Against Neuronal Atrophy and Synapse Loss Provoked by l-alpha Aminoadipic Acid-treated Astrocytes. Neuroscience 2018; 392:38-56. [PMID: 30267830 DOI: 10.1016/j.neuroscience.2018.09.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 09/06/2018] [Accepted: 09/17/2018] [Indexed: 01/01/2023]
Abstract
The impact of treating astrocytes with the astrocytic toxin l-alpha amino adipic acid (L-AAA) on neuronal outgrowth, complexity and synapse formation was assessed, using a model of astrocyte-neuronal interaction. Treatment of rat primary cortical neurons with conditioned media (CM) derived from astrocytes treated with L-AAA reduced neuronal complexity and synapse formation. L-AAA provoked a reduction in the expression of glial fibrillary acid protein (GFAP) and a reduction in ATP-linked mitochondrial respiration in astrocytic cells. As the NMDA-R/PSD-95/NOS signaling pathway is implicated in regulating the structural plasticity of neurons, treatment of neuronal cultures with the neuronal nitric oxide synthase (nNOS) inhibitor 1-[2-(trifluoromethyl)phenyl] imidazole (TRIM) [100 nM] was assessed and observed to protect against L-AAA-treated astrocytic CM-induced reduction in neuronal complexity and synapse loss. Treatment with the NMDA-R antagonist ketamine protected against the CM-induced loss of synapse formation whereas the novel PSD-95/nNOS inhibitors 2-((1H-benzo[d] [1,2,3]triazol-5-ylamino) methyl)-4,6-dichlorophenol (IC87201) and 4-(3,5-dichloro-2-hydroxy-benzylamino)-2-hydroxybenzoic acid (ZL006) protected against synapse loss with partial protection against reduced neurite outgrowth. Furthermore, L-AAA delivery to the pre-limbic cortex (PLC) of mice was found to increase dendritic spine density and treatment with ZL006 reduced this effect. In summary, L-AAA-induced astrocyte impairment leads to a loss of neuronal complexity and synapse loss in vitro and increased dendritic spine density in vivo that may be reversed by inhibitors of the NMDA-R/PSD-95/NOS pathway. The results have implications for understanding astrocytic-neuronal interaction and the search for drug candidates that may provide therapeutic approaches for brain disorders associated with astrocytic histopathology.
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Affiliation(s)
- J David
- Trinity College Institute of Neuroscience & School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland.
| | - E O'Toole
- Trinity College Institute of Neuroscience & School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland.
| | - K O'Reilly
- Trinity College Institute of Neuroscience & School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland.
| | - G Thuery
- Trinity College Institute of Neuroscience & School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland
| | - N Assmann
- Trinity Biomedical Sciences Institute, School of Biochemistry and Immunology & School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland.
| | - D Finlay
- Trinity Biomedical Sciences Institute, School of Biochemistry and Immunology & School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland.
| | - A Harkin
- Trinity College Institute of Neuroscience & School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland.
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19
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Ranjit S, Patters BJ, Gerth KA, Haque S, Choudhary S, Kumar S. Potential neuroprotective role of astroglial exosomes against smoking-induced oxidative stress and HIV-1 replication in the central nervous system. Expert Opin Ther Targets 2018; 22:703-714. [PMID: 30015535 DOI: 10.1080/14728222.2018.1501473] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION HIV-1-infected smokers are at risk of oxidative damage to neuronal cells in the central nervous system by both HIV-1 and cigarette smoke. Since neurons have a weak antioxidant defense system, they mostly depend on glial cells, particularly astrocytes, for protection against oxidative damage and neurotoxicity. Astrocytes augment the neuronal antioxidant system by supplying cysteine-containing products for glutathione synthesis, antioxidant enzymes such as SOD and catalase, glucose for antioxidant regeneration via the pentose-phosphate pathway, and by recycling of ascorbic acid. Areas covered: The transport of antioxidants and energy substrates from astrocytes to neurons could possibly occur via extracellular nanovesicles called exosomes. This review highlights the neuroprotective potential of exosomes derived from astrocytes against smoking-induced oxidative stress, HIV-1 replication, and subsequent neurotoxicity observed in HIV-1-positive smokers. Expert opinion: During stress conditions, the antioxidants released from astrocytes either via extracellular fluid or exosomes to neurons may not be sufficient to provide neuroprotection. Therefore, we put forward a novel strategy to combat oxidative stress in the central nervous system, using synthetically developed exosomes loaded with antioxidants such as glutathione and the anti-aging protein Klotho.
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Affiliation(s)
- Sabina Ranjit
- a Department of Pharmaceutical Sciences , University of Tennessee Health Science Center , Memphis , TN , United States
| | - Benjamin J Patters
- a Department of Pharmaceutical Sciences , University of Tennessee Health Science Center , Memphis , TN , United States
| | - Kelli A Gerth
- a Department of Pharmaceutical Sciences , University of Tennessee Health Science Center , Memphis , TN , United States
| | - Sanjana Haque
- a Department of Pharmaceutical Sciences , University of Tennessee Health Science Center , Memphis , TN , United States
| | - Sanjeev Choudhary
- b Department of Internal Medicine , University of Texas Medical Branch , Galveston , TX , United States
| | - Santosh Kumar
- a Department of Pharmaceutical Sciences , University of Tennessee Health Science Center , Memphis , TN , United States
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20
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Levy MJF, Boulle F, Steinbusch HW, van den Hove DLA, Kenis G, Lanfumey L. Neurotrophic factors and neuroplasticity pathways in the pathophysiology and treatment of depression. Psychopharmacology (Berl) 2018; 235:2195-2220. [PMID: 29961124 PMCID: PMC6061771 DOI: 10.1007/s00213-018-4950-4] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 06/18/2018] [Indexed: 02/06/2023]
Abstract
Depression is a major health problem with a high prevalence and a heavy socioeconomic burden in western societies. It is associated with atrophy and impaired functioning of cortico-limbic regions involved in mood and emotion regulation. It has been suggested that alterations in neurotrophins underlie impaired neuroplasticity, which may be causally related to the development and course of depression. Accordingly, mounting evidence suggests that antidepressant treatment may exert its beneficial effects by enhancing trophic signaling on neuronal and synaptic plasticity. However, current antidepressants still show a delayed onset of action, as well as lack of efficacy. Hence, a deeper understanding of the molecular and cellular mechanisms involved in the pathophysiology of depression, as well as in the action of antidepressants, might provide further insight to drive the development of novel fast-acting and more effective therapies. Here, we summarize the current literature on the involvement of neurotrophic factors in the pathophysiology and treatment of depression. Further, we advocate that future development of antidepressants should be based on the neurotrophin theory.
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Affiliation(s)
- Marion J F Levy
- Centre de Psychiatrie et Neurosciences (Inserm U894), Université Paris Descartes, 102-108 rue de la santé, 75014, Paris, France
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands
- EURON-European Graduate School of Neuroscience, Maastricht, The Netherlands
| | - Fabien Boulle
- Centre de Psychiatrie et Neurosciences (Inserm U894), Université Paris Descartes, 102-108 rue de la santé, 75014, Paris, France
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands
- EURON-European Graduate School of Neuroscience, Maastricht, The Netherlands
| | - Harry W Steinbusch
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands
- EURON-European Graduate School of Neuroscience, Maastricht, The Netherlands
| | - Daniël L A van den Hove
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands
- EURON-European Graduate School of Neuroscience, Maastricht, The Netherlands
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - Gunter Kenis
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands
- EURON-European Graduate School of Neuroscience, Maastricht, The Netherlands
| | - Laurence Lanfumey
- Centre de Psychiatrie et Neurosciences (Inserm U894), Université Paris Descartes, 102-108 rue de la santé, 75014, Paris, France.
- EURON-European Graduate School of Neuroscience, Maastricht, The Netherlands.
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21
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Chun H, An H, Lim J, Woo J, Lee J, Ryu H, Lee CJ. Astrocytic proBDNF and Tonic GABA Distinguish Active versus Reactive Astrocytes in Hippocampus. Exp Neurobiol 2018; 27:155-170. [PMID: 30022867 PMCID: PMC6050417 DOI: 10.5607/en.2018.27.3.155] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 06/26/2018] [Accepted: 06/30/2018] [Indexed: 01/18/2023] Open
Abstract
Astrocytes are the most abundant cell type in the brain and they make close contacts with neurons and blood vessels. They respond dynamically to various environmental stimuli and change their morphological and functional properties. Both physiological and pathological stimuli can induce versatile changes in astrocytes, as this phenomenon is referred to as ‘astrocytic plasticity’. However, the molecular and cellular mechanisms of astrocytic plasticity in response to various stimuli remain elusive, except for the presence of hypertrophy, a conspicuous structural change which is frequently observed in activated or reactive astrocytes. Here, we investigated differential characteristics of astrocytic plasticity in a stimulus-dependent manner. Strikingly, a stab wound brain injury lead to hypertrophy of astrocytes accompanied by increased GABA expression and tonic GABA release in mouse CA1 hippocampus. In contrast, the mice experiencing enriched environment exhibited astrocytic hypertrophy with enhanced proBDNF immunoreactivity but without GABA signal. Based on the results, we define proBDNF-positive/GABA-negative hypertrophic astrocytes as ‘active’ astrocytes and GABA-positive hypertrophic astrocytes as ‘reactive’ astrocytes, respectively. We propose for the first time that astrocytic proBDNF can be a bona fide molecular marker of the active astrocytes, which are distinct from the reactive astrocytes which show hypertrophy but with aberrant GABA.
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Affiliation(s)
- Heejung Chun
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Brain Science Institute, KIST, Seoul 02792, Korea
| | - Heeyoung An
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Brain Science Institute, KIST, Seoul 02792, Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - Jiwoon Lim
- Center for Glia-Neuron Interaction, Brain Science Institute, KIST, Seoul 02792, Korea
| | - Junsung Woo
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jaekwang Lee
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Hoon Ryu
- Center for Neuromedicine, Brain Science Institute, KIST, Seoul 02792, Korea.,Boston University Alzheimer's Disease Center and Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA
| | - C Justin Lee
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Brain Science Institute, KIST, Seoul 02792, Korea.,Division of Bio-Medical Science & Technology, KIST School, KIST, Seoul 02792, Korea
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22
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Tukker AM, Wijnolts FMJ, de Groot A, Westerink RHS. Human iPSC-derived neuronal models for in vitro neurotoxicity assessment. Neurotoxicology 2018; 67:215-225. [PMID: 29909083 DOI: 10.1016/j.neuro.2018.06.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 04/24/2018] [Accepted: 06/12/2018] [Indexed: 10/28/2022]
Abstract
Neurotoxicity testing still relies on ethically debated, expensive and time consuming in vivo experiments, which are unsuitable for high-throughput toxicity screening. There is thus a clear need for a rapid in vitro screening strategy that is preferably based on human-derived neurons to circumvent interspecies translation. Recent availability of commercially obtainable human induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes holds great promise in assisting the transition from the current standard of rat primary cortical cultures to an animal-free alternative. We therefore composed several hiPSC-derived neuronal models with different ratios of excitatory and inhibitory neurons in the presence or absence of astrocytes. Using immunofluorescent stainings and multi-well micro-electrode array (mwMEA) recordings we demonstrate that these models form functional neuronal networks that become spontaneously active. The differences in development of spontaneous neuronal activity and bursting behavior as well as spiking patterns between our models confirm the importance of the presence of astrocytes. Preliminary neurotoxicity assessment demonstrates that these cultures can be modulated with known seizurogenic compounds, such as picrotoxin (PTX) and endosulfan, and the neurotoxicant methylmercury (MeHg). However, the chemical-induced effects on different parameters for neuronal activity, such as mean spike rate (MSR) and mean burst rate (MBR), may depend on the ratio of inhibitory and excitatory neurons. Our results thus indicate that hiPSC-derived neuronal models must be carefully designed and characterized prior to large-scale use in neurotoxicity screening.
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Affiliation(s)
- Anke M Tukker
- Neurotoxicology Research Group, Toxicology and Pharmacology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands
| | - Fiona M J Wijnolts
- Neurotoxicology Research Group, Toxicology and Pharmacology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands
| | - Aart de Groot
- Neurotoxicology Research Group, Toxicology and Pharmacology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Toxicology and Pharmacology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands.
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23
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Onoda A, Takeda K, Umezawa M. Pretreatment with N-acetyl cysteine suppresses chronic reactive astrogliosis following maternal nanoparticle exposure during gestational period. Nanotoxicology 2017; 11:1012-1025. [PMID: 29046125 DOI: 10.1080/17435390.2017.1388864] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Early pregnant employees are potentially and unintendedly exposed to industrial chemicals including nanoparticles. Developmental toxicity of nanoparticle exposure has been concerned because exposure to fine particle including carbon black nanoparticle (CB-NP) during the brain developmental stage enhances the risk of brain disorders. Maternal CB-NP exposure dose-dependently induces astrogliosis, which is an abnormal increase in the reactive astrocytes with glial fibrillary acidic protein (GFAP) and aquaporin-4 overexpression due to the destruction of nearby neurons and blood vessels. The present study aimed to investigate protective effects of antioxidants on the histopathological denaturation with astrogliosis following maternal CB-NP exposure in offspring mice, thereby to evaluate the role of oxidative stress on the developmental toxicity. Pregnant ICR mice were treated with CB-NP by intranasal instillation on gestational days 5 and 9. N-acetyl cysteine (NAC) or ascorbic acid was intraperitoneally administered to the pregnant mice 1 h prior to CB-NP instillation. The brains were collected from 6- to 12-week-old offspring mice and analyzed using western blotting and immunohistochemistry. NAC suppressed GFAP overexpression in 6- and 12-week-old offspring mice following maternal CB-NP exposure. However, NAC did not suppress aquaporin-4 overexpression following maternal CB-NP exposure. Ascorbic acid did not suppress, but rather slightly and significantly enhanced the expression of GFAP and aquaporin-4. These results indicate that astrogliosis by maternal CB-NP exposure is partially prevented by NAC pretreatment. Oxidative stress is a possible key factor of developmental neurotoxicity of maternal NP exposure. This study will contribute to elucidating the mechanisms underlying the effects of developmental neurotoxicity of NPs.
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Affiliation(s)
- Atsuto Onoda
- a Department of Hygienic Chemistry, Graduate School of Pharmaceutical Sciences , Tokyo University of Science , Noda , Chiba , Japan.,b The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology , Organization for Research Advancement, Tokyo University of Science , Noda , Chiba , Japan.,c Research Fellow of Japan Society for the Promotion of Science , Chiyoda-ku , Tokyo , Japan
| | - Ken Takeda
- b The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology , Organization for Research Advancement, Tokyo University of Science , Noda , Chiba , Japan
| | - Masakazu Umezawa
- b The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology , Organization for Research Advancement, Tokyo University of Science , Noda , Chiba , Japan.,d Department of Materials Science and Technology, Faculty of Industrial Science and Technology , Tokyo University of Science , Katsushika , Tokyo , Japan
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Macedo-Júnior SJ, Luiz-Cerutti M, Nascimento DB, Farina M, Soares Santos AR, de Azevedo Maia AH. Methylmercury exposure for 14 days (short-term) produces behavioral and biochemical changes in mouse cerebellum, liver, and serum. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:1145-1155. [PMID: 28850017 DOI: 10.1080/15287394.2017.1357324] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Various studies on methylmercury (MeHg)-induced toxicity focused on the central nervous system (CNS) as a primary target. However, MeHg-mediated toxicity is related to metallic interaction with electrophilic groups, which are not solely restricted to the CNS, but these reactive groups are present ubiquitously in several systems/organs. The aim of this study was thus to examine MeHg-induced systemic toxicity in mice using a standardized neurotoxicology testing exposure model to measure cerebellar neurotoxicity by determining biochemical and behavioral parameters in the cerebellum. After 2 weeks exposure to MeHg (40 µg/ml; diluted in drinking water; ad libitum), adult male Swiss mice showed a marked motor impairment characteristic of cerebellar toxicity as noted in the following tests: rotarod, beam walking, pole, and hind limb clasping. MeHg treatment resulted in Hg deposition in the cerebellum as well as reduction in cerebellar weight, glutathione peroxidase (GPx) activity, and interleukin (IL)-6 levels. MeHg ingestion increased cerebellar glutathione reductase (GR) activity and brain-derived neurotrophic factor (BDNF) levels. In addition to cerebellar toxicity, MeHg treatment also elevated total and non-high density lipoprotein (non-HDL) cholesterol levels, as well as serum aspartate transaminase (AST) and alanine transaminase (ALT) enzymatic activities, systemic parameters. Increased liver weight and reduced serum urea levels were also noted in MeHg-exposed mice. Taken together, our findings demonstrated that a well-standardized exposure protocol to examine MeHg-induced neurotoxicity also produced systemic toxicity in mice, which was characterized by changes in markers of hepatic function as well as serum lipid homeostasis.
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Affiliation(s)
- Sérgio José Macedo-Júnior
- a Programa de Pós-Graduação em Farmacologia, Departamento de Farmacologia , Centro de Ciências Biológicas, Universidade Federal de Santa Catarina , Florianópolis , SC , Brazil
| | - Murilo Luiz-Cerutti
- b Departamento de Ciências Fisiológicas, Centro de Ciências Biológicas , Universidade Federal de Santa Catarina , Florianópolis , SC , Brazil
| | - Denise B Nascimento
- c Departamento de Química, Centro de Ciências Naturais e Exatas , Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Marcelo Farina
- d Departamento de Bioquímica, Centro de Ciências Biológicas , Universidade Federal de Santa Catarina , Florianópolis , SC , Brazil
| | - Adair Roberto Soares Santos
- b Departamento de Ciências Fisiológicas, Centro de Ciências Biológicas , Universidade Federal de Santa Catarina , Florianópolis , SC , Brazil
| | - Alcíbia Helena de Azevedo Maia
- e Departamento de Patologia, Centro de Ciências da Saúde , Universidade Federal de Santa Catarina , Florianópolis , SC , Brazil
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25
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Hernández RG, Silva-Hucha S, Morcuende S, de la Cruz RR, Pastor AM, Benítez-Temiño B. Extraocular Motor System Exhibits a Higher Expression of Neurotrophins When Compared with Other Brainstem Motor Systems. Front Neurosci 2017; 11:399. [PMID: 28744196 PMCID: PMC5504184 DOI: 10.3389/fnins.2017.00399] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 06/26/2017] [Indexed: 01/01/2023] Open
Abstract
Extraocular motoneurons resist degeneration in diseases such as amyotrophic lateral sclerosis. The main objective of the present work was to characterize the presence of neurotrophins in extraocular motoneurons and muscles of the adult rat. We also compared these results with those obtained from other cranial motor systems, such as facial and hypoglossal, which indeed suffer neurodegeneration. Immunocytochemical analysis was used to describe the expression of nerve growth factor, brain-derived neurotrophic factor and neurotrophin-3 in oculomotor, trochlear, abducens, facial, and hypoglossal nuclei of adult rats, and Western blots were used to describe the presence of neurotrophins in extraocular, facial (buccinator), and tongue muscles, which are innervated by the above-mentioned motoneurons. In brainstem samples, brain-derived neurotrophic factor was present both in extraocular and facial motoneuron somata, and to a lesser degree, in hypoglossal motoneurons. Neurotrophin-3 was present in extraocular motor nuclei, while facial and hypoglossal motoneurons were almost devoid of this protein. Finally, nerve growth factor was not present in the soma of any group of motoneurons, although it was present in dendrites of motoneurons located in the neuropil. Neuropil optical density levels were higher in extraocular motoneuron nuclei when compared with facial and hypoglossal nuclei. Neurotrophins could be originated in target muscles, since Western blot analyses revealed the presence of the three molecules in all sampled muscles, to a larger extent in extraocular muscles when compared with facial and tongue muscles. We suggest that the different neurotrophin availability could be related to the particular resistance of extraocular motoneurons to neurodegeneration.
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26
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Ghouili I, Bahdoudi S, Morin F, Amri F, Hamdi Y, Coly PM, Walet-Balieu ML, Leprince J, Zekri S, Vaudry H, Vaudry D, Castel H, Amri M, Tonon MC, Masmoudi-Kouki O. Endogenous Expression of ODN-Related Peptides in Astrocytes Contributes to Cell Protection Against Oxidative Stress: Astrocyte-Neuron Crosstalk Relevance for Neuronal Survival. Mol Neurobiol 2017; 55:4596-4611. [PMID: 28698967 DOI: 10.1007/s12035-017-0630-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 05/22/2017] [Indexed: 11/29/2022]
Abstract
Astroglial cells are important actors in the defense of brain against oxidative stress injuries. Glial cells synthesize and release the octadecaneuropeptide ODN, a diazepam-binding inhibitor (DBI)-related peptide, which acts through its metabotropic receptor to protect neurons and astrocytes from oxidative stress-induced apoptosis. The purpose of the present study is to examine the contribution of the endogenous ODN in the protection of astrocytes and neurons from moderate oxidative stress. The administration of H2O2 (50 μM, 6 h) induced a moderate oxidative stress in cultured astrocytes, i.e., an increase in reactive oxygen species, malondialdehyde, and carbonyl group levels, but it had no effect on astrocyte death. Mass spectrometry and QPCR analysis revealed that 50 μM H2O2 increased ODN release and DBI mRNA levels. The inhibition of ODN release or pharmacological blockage of the effects of ODN revealed that in these conditions, 50 μM H2O2 induced the death of astrocytes. The transfection of astrocytes with DBI siRNA increased the vulnerability of cells to moderate stress. Finally, the addition of 1 nM ODN to culture media reversed cell death observed in DBI-deficient astrocytes. The treatment of neurons with media from 50 μM H2O2-stressed astrocytes significantly reduced the neuronal death induced by H2O2; this effect is greatly attenuated by the administration of an ODN metabotropic receptor antagonist. Overall, these results indicate that astrocytes produce authentic ODN, notably in a moderate oxidative stress situation, and this glio- and neuro-protective agent may form part of the brain defense mechanisms against oxidative stress injury.
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Affiliation(s)
- Ikram Ghouili
- Université de Tunis El Manar, Faculté des Sciences de Tunis, Research Unit UR/11ES09, Laboratory of Functional Neurophysiology and Pathology, 2092, Tunis, Tunisia
| | - Seyma Bahdoudi
- Université de Tunis El Manar, Faculté des Sciences de Tunis, Research Unit UR/11ES09, Laboratory of Functional Neurophysiology and Pathology, 2092, Tunis, Tunisia.,Inserm U1239, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandie, 76128, Mont-Saint-Aignan, France
| | - Fabrice Morin
- Inserm U1239, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandie, 76128, Mont-Saint-Aignan, France
| | - Fatma Amri
- Université de Tunis El Manar, Faculté des Sciences de Tunis, Research Unit UR/11ES09, Laboratory of Functional Neurophysiology and Pathology, 2092, Tunis, Tunisia
| | - Yosra Hamdi
- Université de Tunis El Manar, Faculté des Sciences de Tunis, Research Unit UR/11ES09, Laboratory of Functional Neurophysiology and Pathology, 2092, Tunis, Tunisia
| | - Pierre Michael Coly
- Inserm U1239, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandie, 76128, Mont-Saint-Aignan, France
| | - Marie-Laure Walet-Balieu
- Regional Proteomic Platform (Pissaro), IRIB, University of Rouen Normandie, Mont-Saint-Aignan, France
| | - Jérôme Leprince
- Inserm U1239, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandie, 76128, Mont-Saint-Aignan, France.,Regional Platform for Cell Imaging of Normandie (PRIMACEN), IRIB, University of Rouen Normandie, Mont-Saint-Aignan, France.,International Associated Laboratory Samuel de Champlain, University of Rouen Normandie, Mont-Saint-Aignan, France
| | - Sami Zekri
- Electron Microscopy Laboratory, Faculty of Medicine of Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Hubert Vaudry
- Regional Platform for Cell Imaging of Normandie (PRIMACEN), IRIB, University of Rouen Normandie, Mont-Saint-Aignan, France.,International Associated Laboratory Samuel de Champlain, University of Rouen Normandie, Mont-Saint-Aignan, France
| | - David Vaudry
- Inserm U1239, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandie, 76128, Mont-Saint-Aignan, France.,Regional Proteomic Platform (Pissaro), IRIB, University of Rouen Normandie, Mont-Saint-Aignan, France.,Regional Platform for Cell Imaging of Normandie (PRIMACEN), IRIB, University of Rouen Normandie, Mont-Saint-Aignan, France.,International Associated Laboratory Samuel de Champlain, University of Rouen Normandie, Mont-Saint-Aignan, France
| | - Hélène Castel
- Inserm U1239, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandie, 76128, Mont-Saint-Aignan, France
| | - Mohamed Amri
- Université de Tunis El Manar, Faculté des Sciences de Tunis, Research Unit UR/11ES09, Laboratory of Functional Neurophysiology and Pathology, 2092, Tunis, Tunisia
| | - Marie-Christine Tonon
- Inserm U1239, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandie, 76128, Mont-Saint-Aignan, France.
| | - Olfa Masmoudi-Kouki
- Université de Tunis El Manar, Faculté des Sciences de Tunis, Research Unit UR/11ES09, Laboratory of Functional Neurophysiology and Pathology, 2092, Tunis, Tunisia.
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27
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Distinct effects on the dendritic arbor occur by microbead versus bath administration of brain-derived neurotrophic factor. Cell Mol Life Sci 2017; 74:4369-4385. [PMID: 28698933 DOI: 10.1007/s00018-017-2589-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 06/15/2017] [Accepted: 07/06/2017] [Indexed: 12/18/2022]
Abstract
Proper communication among neurons depends on an appropriately formed dendritic arbor, and thus, aberrant changes to the arbor are implicated in many pathologies, ranging from cognitive disorders to neurodegenerative diseases. Due to the importance of dendritic shape to neuronal network function, the morphology of dendrites is tightly controlled and is influenced by both intrinsic and extrinsic factors. In this work, we examine how brain-derived neurotrophic factor (BDNF), one of the most well-studied extrinsic regulators of dendritic branching, affects the arbor when it is applied locally via microbeads to cultures of hippocampal neurons. We found that local application of BDNF increases both proximal and distal branching in a time-dependent manner and that local BDNF application attenuates pruning of dendrites that occurs with neuronal maturation. Additionally, we examined whether cytosolic PSD-95 interactor (cypin), an intrinsic regulator of dendritic branching, plays a role in these changes and found strong evidence for the involvement of cypin in BDNF-promoted increases in dendrites after 24 but not 48 h of application. This current study extends our previous work in which we found that bath application of BDNF for 72 h, but not shorter times, increases proximal dendrite branching and that this increase occurs through transcriptional regulation of cypin. Moreover, this current work illustrates how dendritic branching is regulated differently by the same growth factor depending on its spatial localization, suggesting a novel pathway for modulation of dendritic branching locally.
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28
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Mizuno G, Munetsuna E, Yamada H, Ando Y, Yamazaki M, Murase Y, Kondo K, Ishikawa H, Teradaira R, Suzuki K, Ohashi K. Fructose intake during gestation and lactation differentially affects the expression of hippocampal neurosteroidogenic enzymes in rat offspring. Endocr Res 2017; 42:71-77. [PMID: 27260693 DOI: 10.1080/07435800.2016.1182186] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neurosteroids, steroidal hormones synthesized de novo from cholesterol within the brain, stimulate hippocampal functions such as neuron protection and synapse formation. Previously, we examined the effect of maternal fructose on the transcriptional regulation of neurosteroidogenic enzymes. We found that the mRNA expression level of the steroidogenic acute regulatory protein (StAR), peripheral benzodiazepine receptor (PBR), cytochrome P450(11β), 11β-hydroxysteroid dehydrogenase (HSD), and 17β-HSD was altered. However, we could not determine whether maternal fructose intake played a role in the gestation or lactation period because the dam rats were fed fructose solution during both periods. Thus, in this study, we analyzed the hippocampi of the offspring of dams fed fructose during the gestation or lactation period. Maternal fructose consumption during either the gestation or lactation period did not affect the mRNA levels of StAR, P450(17α), 11β-HSD-2, and 17β-HSD-1. PBR expression was down-regulated, even when rats consumed fructose during the lactation period only, while fructose consumption during gestation tended to activate the expression of P450(11β)-2. We found that maternal fructose intake during gestation and lactation differentially affected the expression of hippocampal neurosteroidogenic enzymes in the offspring.
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Affiliation(s)
- Genki Mizuno
- a Department of Clinical Biochemistry , Fujita Health University School of Health Sciences , Toyoake , Japan
| | - Eiji Munetsuna
- b Department of Biochemistry , Fujita Health University School of Medicine , Toyoake , Japan
| | - Hiroya Yamada
- c Department of Hygiene , Fujita Health University School of Medicine , Toyoake , Japan
| | - Yoshitaka Ando
- d Department of Joint Research Laboratory of Clinical Medicine , Fujita Health University School of Medicine , Toyoake , Japan
| | - Mirai Yamazaki
- a Department of Clinical Biochemistry , Fujita Health University School of Health Sciences , Toyoake , Japan
| | - Yuri Murase
- a Department of Clinical Biochemistry , Fujita Health University School of Health Sciences , Toyoake , Japan
| | - Kanako Kondo
- a Department of Clinical Biochemistry , Fujita Health University School of Health Sciences , Toyoake , Japan
| | - Hiroaki Ishikawa
- a Department of Clinical Biochemistry , Fujita Health University School of Health Sciences , Toyoake , Japan
| | - Ryoji Teradaira
- a Department of Clinical Biochemistry , Fujita Health University School of Health Sciences , Toyoake , Japan
| | - Koji Suzuki
- e Department of Public Health , Fujita Health University School of Health Sciences , Toyoake , Japan
| | - Koji Ohashi
- a Department of Clinical Biochemistry , Fujita Health University School of Health Sciences , Toyoake , Japan
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29
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Heimfarth L, da Silva Ferreira F, Pierozan P, Mingori MR, Moreira JCF, da Rocha JBT, Pessoa-Pureur R. Astrocyte-neuron interaction in diphenyl ditelluride toxicity directed to the cytoskeleton. Toxicology 2017; 379:1-11. [PMID: 28137618 DOI: 10.1016/j.tox.2017.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/05/2017] [Accepted: 01/23/2017] [Indexed: 01/04/2023]
Abstract
Diphenylditelluride (PhTe)2 is a neurotoxin that disrupts cytoskeletal homeostasis. We are showing that different concentrations of (PhTe)2 caused hypophosphorylation of glial fibrillary acidic protein (GFAP), vimentin and neurofilament subunits (NFL, NFM and NFH) and altered actin organization in co-cultured astrocytes and neurons from cerebral cortex of rats. These mechanisms were mediated by N-methyl-d-aspartate (NMDA) receptors without participation of either L-type voltage-dependent calcium channels (L-VDCC) or metabotropic glutamate receptors. Upregulated Ca2+ influx downstream of NMDA receptors activated Ca2+-dependent protein phosphatase 2B (PP2B) causing hypophosphorylation of astrocyte and neuron IFs. Immunocytochemistry showed that hypophosphorylated intermediate filaments (IF) failed to disrupt their organization into the cytoskeleton. However, phalloidin-actin-FITC stained cytoskeleton evidenced misregulation of actin distribution, cell spreading and increased stress fibers in astrocytes. βIII tubulin staining showed that neurite meshworks are not altered by (PhTe)2, suggesting greater susceptibility of astrocytes than neurons to (PheTe)2 toxicity. These findings indicate that signals leading to IF hypophosphorylation fail to disrupt the cytoskeletal IF meshwork of interacting astrocytes and neurons in vitro however astrocyte actin network seems more susceptible. Our findings support that intracellular Ca2+ is one of the crucial signals that modulate the action of (PhTe)2 in co-cultured astrocytes and neurons and highlights the cytoskeleton as an end-point of the neurotoxicity of this compound. Cytoskeletal misregulation is associated with cell dysfunction, therefore, the understanding of the molecular mechanisms mediating the neurotoxicity of this compound is a matter of increasing interest since tellurium compounds are increasingly released in the environment.
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Affiliation(s)
- Luana Heimfarth
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | | | - Paula Pierozan
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | - Moara Rodrigues Mingori
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | | | | | - Regina Pessoa-Pureur
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil.
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30
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Lloyd BA, Hake HS, Ishiwata T, Farmer CE, Loetz EC, Fleshner M, Bland ST, Greenwood BN. Exercise increases mTOR signaling in brain regions involved in cognition and emotional behavior. Behav Brain Res 2017; 323:56-67. [PMID: 28130174 DOI: 10.1016/j.bbr.2017.01.033] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/11/2017] [Accepted: 01/18/2017] [Indexed: 12/21/2022]
Abstract
Exercise can enhance learning and memory and produce resistance against stress-related psychiatric disorders such as depression and anxiety. In rats, these beneficial effects of exercise occur regardless of exercise controllability: both voluntary and forced wheel running produce stress-protective effects. The mechanisms underlying these beneficial effects of exercise remain unknown. The mammalian target of rapamycin (mTOR) is a translation regulator important for cell growth, proliferation, and survival. mTOR has been implicated in enhancing learning and memory as well as antidepressant effects. Moreover, mTOR is sensitive to exercise signals such as metabolic factors. The effects of exercise on mTOR signaling, however, remain unknown. The goal of the present study was to test the hypothesis that exercise, regardless of controllability, increases levels of phosphorylated mTOR (p-mTOR) in brain regions important for learning and emotional behavior. Rats were exposed to 6 weeks of either sedentary (locked wheel), voluntary, or forced wheel running conditions. At 6 weeks, rats were sacrificed during peak running and levels of p-mTOR were measured using immunohistochemistry. Overall, both voluntary and forced exercise increased p-mTOR-positive neurons in the medial prefrontal cortex, striatum, hippocampus, hypothalamus, and amygdala compared to locked wheel controls. Exercise, regardless of controllability, also increased numbers of p-mTOR-positive glia in the striatum, hippocampus, and amygdala. For both neurons and glia, the largest increase in p-mTOR positive cells was observed after voluntary running, with forced exercise causing a more modest increase. Interestingly, voluntary exercise preferentially increased p-mTOR in astrocytes (GFAP+), while forced running increased p-mTOR in microglia (CD11+) in the inferior dentate gyrus. Results suggest that mTOR signaling is sensitive to exercise, but subtle differences exist depending on exercise controllability. Increases in mTOR signaling could contribute to the beneficial effects of exercise on cognitive function and mental health.
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Affiliation(s)
- Brian A Lloyd
- Department of Psychology, University of Colorado Denver, United States
| | - Holly S Hake
- Department of Psychology, University of Colorado Denver, United States
| | | | - Caroline E Farmer
- Department of Psychology, University of Colorado Denver, United States
| | - Esteban C Loetz
- Department of Psychology, University of Colorado Denver, United States
| | - Monika Fleshner
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, United States
| | - Sondra T Bland
- Department of Psychology, University of Colorado Denver, United States
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31
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Ishihara Y, Tsuji M, Kawamoto T, Yamazaki T. Involvement of reactive oxygen species derived from mitochondria in neuronal injury elicited by methylmercury. J Clin Biochem Nutr 2016; 59:182-190. [PMID: 27895385 PMCID: PMC5110935 DOI: 10.3164/jcbn.16-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/04/2016] [Indexed: 01/02/2023] Open
Abstract
Methylmercury induces oxidative stress and subsequent neuronal injury. However, the mechanism by which methylmercury elicits reactive oxygen species (ROS) production remains under debate. In this study, we investigated the involvement of mitochondrial ROS in methylmercury-induced neuronal cell injury using human neuroblastoma SH-SY5Y-derived ρ0 cells, which have a deletion of mitochondrial DNA and thus decreased respiratory activity. SH-SY5Y cells were cultured for 60 days in the presence of ethidium bromide to produce ρ0 cells. Our ρ0 cells showed decreases in the cytochrome c oxidase expression and activity as well as oxygen consumption compared with original SH-SY5Y cells. Methylmercury at a concentration of 1 µM induced cell death with oxidative stress in original SH-SY5Y cells, but not ρ0 cells, indicating that ρ0 cells are resistant to methylmercury-induced oxidative stress. ρ0 cells also showed tolerance against hydrogen peroxide and superoxide anion, suggesting that ρ0 cells are resistant to total ROS. These data indicate that mitochondrial ROS are clearly involved in oxidative stress and subsequent cell death induced by methylmercury. Considering that the dominant mechanism of ROS generation elicited by methylmercury is due to direct antioxidant enzyme inhibition, mitochondria might play a role in amplifying ROS in methylmercury-induced neurotoxicity.
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Affiliation(s)
- Yasuhiro Ishihara
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Mayumi Tsuji
- Department of Environmental Health, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahata-nishi-ku, Kitakyushu, Fukuoka 807-8555, Japan
| | - Toshihiro Kawamoto
- Department of Environmental Health, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahata-nishi-ku, Kitakyushu, Fukuoka 807-8555, Japan
| | - Takeshi Yamazaki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
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32
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Lafourcade C, Ramírez JP, Luarte A, Fernández A, Wyneken U. MiRNAs in Astrocyte-Derived Exosomes as Possible Mediators of Neuronal Plasticity. J Exp Neurosci 2016; 10:1-9. [PMID: 27547038 PMCID: PMC4978198 DOI: 10.4137/jen.s39916] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/07/2016] [Accepted: 07/09/2016] [Indexed: 12/21/2022] Open
Abstract
Astrocytes use gliotransmitters to modulate neuronal function and plasticity. However, the role of small extracellular vesicles, called exosomes, in astrocyte-to-neuron signaling is mostly unknown. Exosomes originate in multivesicular bodies of parent cells and are secreted by fusion of the multivesicular body limiting membrane with the plasma membrane. Their molecular cargo, consisting of RNA species, proteins, and lipids, is in part cell type and cell state specific. Among the RNA species transported by exosomes, microRNAs (miRNAs) are able to modify gene expression in recipient cells. Several miRNAs present in astrocytes are regulated under pathological conditions, and this may have far-reaching consequences if they are loaded in exosomes. We propose that astrocyte-derived miRNA-loaded exosomes, such as miR-26a, are dysregulated in several central nervous system diseases; thus potentially controlling neuronal morphology and synaptic transmission through validated and predicted targets. Unraveling the contribution of this new signaling mechanism to the maintenance and plasticity of neuronal networks will impact our understanding on the physiology and pathophysiology of the central nervous system.
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Affiliation(s)
- Carlos Lafourcade
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de los Andes, Chile
| | - Juan Pablo Ramírez
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de los Andes, Chile
| | - Alejandro Luarte
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de los Andes, Chile
| | - Anllely Fernández
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de los Andes, Chile
| | - Ursula Wyneken
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de los Andes, Chile
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Long-term consequences of prenatal stress and neurotoxicants exposure on neurodevelopment. Prog Neurobiol 2016; 155:21-35. [PMID: 27236051 DOI: 10.1016/j.pneurobio.2016.05.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 02/19/2016] [Accepted: 05/24/2016] [Indexed: 11/20/2022]
Abstract
There is a large consensus that the prenatal environment determines the susceptibility to pathological conditions later in life. The hypothesis most widely accepted is that exposure to insults inducing adverse conditions in-utero may have negative effects on the development of target organs, disrupting homeostasis and increasing the risk of diseases at adulthood. Several models have been proposed to investigate the fetal origins of adult diseases, but although these approaches hold true for almost all diseases, particular attention has been focused on disorders related to the central nervous system, since the brain is particularly sensitive to alterations of the microenvironment during early development. Neurobiological disorders can be broadly divided into developmental, neurodegenerative and neuropsychiatric disorders. Even though most of these diseases share genetic risk factors, the onset of the disorders cannot be explained solely by inheritance. Therefore, current understanding presumes that the interactions of environmental input, may lead to different disorders. Among the insults that can play a direct or indirect role in the development of neurobiological disorders are stress, infections, drug abuse, and environmental contaminants. Our laboratories have been involved in the study of the neurobiological impact of gestational stress on the offspring (Dr. Antonelli's lab) and on the effect of gestational exposure to toxicants, mainly methyl mercury (MeHg) and perfluorinated compounds (PFCs) (Dr. Ceccatelli's lab). In this focused review, we will review the specialized literature but we will concentrate mostly on our own work on the long term neurodevelopmental consequences of gestational exposure to stress and neurotoxicants.
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Ishihara Y, Takemoto T, Itoh K, Ishida A, Yamazaki T. Dual role of superoxide dismutase 2 induced in activated microglia: oxidative stress tolerance and convergence of inflammatory responses. J Biol Chem 2015; 290:22805-17. [PMID: 26231211 DOI: 10.1074/jbc.m115.659151] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Indexed: 12/13/2022] Open
Abstract
Microglia are activated quickly in response to external pathogens or cell debris and clear these substances via the inflammatory response. However, excessive activation of microglia can be harmful to host cells due to the increased production of reactive oxygen species and proinflammatory cytokines. Superoxide dismutase 2 (SOD2) is reportedly induced under various inflammatory conditions in the central nervous system. We herein demonstrated that activated microglia strongly express SOD2 and examined the role of SOD2, focusing on regulation of the microglial activity and the susceptibility of microglia to oxidative stress. When rat primary microglia were treated with LPS, poly(I:C), peptidoglycan, or CpG oligodeoxynucleotide, respectively, the mRNA and protein levels of SOD2 largely increased. However, an increased expression of SOD2 was not detected in the primary neurons or astrocytes, indicating that SOD2 is specifically induced in microglia under inflammatory conditions. The activated microglia showed high tolerance to oxidative stress, whereas SOD2 knockdown conferred vulnerability to oxidative stress. Interestingly, the production of proinflammatory cytokines was increased in the activated microglia treated with SOD2 siRNA compared with that observed in the control siRNA-treated cells. Pretreatment with NADPH oxidase inhibitors, diphenylene iodonium and apocynin, decreased in not only reactive oxygen species generation but also the proinflammatory cytokine expression. Notably, SOD2 knockdown largely potentiated the nuclear factor κB activity in the activated microglia. Taken together, increased SOD2 conferred tolerance to oxidative stress in the microglia and decreased proinflammatory cytokine production by attenuating the nuclear factor κB activity. Therefore, SOD2 might regulate neuroinflammation by controlling the microglial activities.
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Affiliation(s)
- Yasuhiro Ishihara
- From the Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan and
| | - Takuya Takemoto
- From the Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan and
| | - Kouichi Itoh
- the Laboratory for Brain Science, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa, 769-2193, Japan
| | - Atsuhiko Ishida
- From the Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan and
| | - Takeshi Yamazaki
- From the Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan and
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