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Zhang K, Yang Z, Yang Z, Du L, Zhou Y, Fu S, Wang X, Li X, Liu D, He X. The m6A reader YTHDC2 promotes the pathophysiology of temporal lobe epilepsy by modulating SLC7A11-dependent glutamate dysregulation in astrocytes. Theranostics 2024; 14:5551-5570. [PMID: 39310099 PMCID: PMC11413790 DOI: 10.7150/thno.100703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Accepted: 08/22/2024] [Indexed: 09/25/2024] Open
Abstract
Rationale: Epilepsy affects over 70 million people globally, with temporal lobe epilepsy with hippocampal sclerosis (TLE-HS) often progressing to a drug-resistant state. Recent research has highlighted the role of reactive astrocytes and glutamate dysregulation in epilepsy pathophysiology. This study aims to investigate the involvement of astrocytic xCT, a glutamate-cystine antiporter, and its regulation by the m6A reader protein YTHDC2 in TLE-HS. Methods: A pilocarpine-induced epilepsy model in mice was used to study the role of xCT in reactive astrocytes. The expression of xCT and its regulation by YTHDC2 were assessed through various molecular and cellular techniques. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used to measure mRNA and protein levels of xCT and YTHDC2, respectively; immunofluorescence was utilized to visualize their localization and expression in astrocytes. In vivo glutamate measurements were conducted using microdialysis to monitor extracellular glutamate levels in the hippocampus. RNA immunoprecipitation-qPCR (RIP-qPCR) was performed to investigate the binding of YTHDC2 to SLC7A11 mRNA, while methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) was performed to quantify m6A modifications on SLC7A11 mRNA. A dual-luciferase reporter assay was conducted to assess the effect of m6A modifications on SLC7A11 mRNA translation, and polysome profiling was employed to evaluate the translational efficiency of SLC7A11 mRNA. Inhibition experiments involved shRNA-mediated knockdown of SLC7A11 (commonly known as xCT) and YTHDC2 expression in astrocytes. Video-electroencephalogram (EEG) recordings were used to monitor seizure activity in mice. Results: The xCT transporter in reactive astrocytes significantly contributes to elevated extracellular glutamate levels, enhancing neuronal excitability and seizure activity. Increased xCT expression is influenced by the m6A reader protein YTHDC2, which regulates its expression through m6A methylation. Inhibition of xCT or YTHDC2 in astrocytes reduces glutamate levels and effectively controls seizures in a mouse model. Specifically, mice with SLC7A11- or YTHDC2-knockdown astrocytes showed decreased glutamate concentration in the hippocampus and reduced frequency and duration of epileptic seizures. Conclusions: This study highlights the therapeutic potential of targeting YTHDC2 and xCT in reactive astrocytes to mitigate epilepsy. The findings provide a novel perspective on the mechanisms of glutamate dysregulation and their implications in seizure pathophysiology, suggesting that modulation of YTHDC2 and xCT could be a promising strategy for treating TLE.
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Affiliation(s)
- Kai Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Zhiquan Yang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Zhuanyi Yang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Liangchao Du
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yu Zhou
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Shiyu Fu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaoyue Wang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Xing Li
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Central South University, Changsha 410078, Hunan Province, China
| | - Dingyang Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Xinghui He
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
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2
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Li D, Li S, Pan M, Li Q, Song J, Zhang R. The role of extracellular glutamate homeostasis dysregulated by astrocyte in epileptic discharges: a model evidence. Cogn Neurodyn 2024; 18:485-502. [PMID: 38699615 PMCID: PMC11061099 DOI: 10.1007/s11571-023-10001-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/26/2023] [Accepted: 08/13/2023] [Indexed: 05/05/2024] Open
Abstract
Glutamate (Glu) is a predominant excitatory neurotransmitter that acts on glutamate receptors to transfer signals in the central nervous system. Abnormally elevated extracellular glutamate levels is closely related to the generation and transition of epileptic seizures. However, there lacks of investigation regarding the role of extracellular glutamate homeostasis dysregulated by astrocyte in neuronal epileptic discharges. According to this, we propose a novel neuron-astrocyte computational model (NAG) by incorporating extracellular Glu concentration dynamics from three aspects of regulatory mechanisms: (1) the Glu uptake through astrocyte EAAT2; (2) the binding and release Glu via activating astrocyte mGluRs; and (3) the Glu free diffusion in the extracellular space. Then the proposed model NAG is analyzed theoretically and numerically to verify the effect of extracellular Glu homeostasis dysregulated by such three regulatory mechanisms on neuronal epileptic discharges. Our results demonstrate that the neuronal epileptic discharges can be aggravated by the downregulation expression of EAAT2, the aberrant activation of mGluRs, and the elevated Glu levels in extracellular micro-environment; as well as various discharge states (including bursting, mixed-mode spiking, and tonic firing) can be transited by their combination. Furthermore, we find that such factors can also alter the bifurcation threshold for the generation and transition of epileptic discharges. The results in this paper can be helpful for researchers to understand the astrocyte role in modulating extracellular Glu homeostasis, and provide theoretical basis for future related experimental studies.
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Affiliation(s)
- Duo Li
- The Medical Big Data Research Center and The School of Mathematics, Northwest University, Xi’an, 710127 China
| | - Sihui Li
- The Medical Big Data Research Center and The School of Mathematics, Northwest University, Xi’an, 710127 China
| | - Min Pan
- The Medical Big Data Research Center and The School of Mathematics, Northwest University, Xi’an, 710127 China
| | - Qiang Li
- The Medical Big Data Research Center and The School of Mathematics, Northwest University, Xi’an, 710127 China
| | - Jiangling Song
- The Medical Big Data Research Center and The School of Mathematics, Northwest University, Xi’an, 710127 China
| | - Rui Zhang
- The Medical Big Data Research Center and The School of Mathematics, Northwest University, Xi’an, 710127 China
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3
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Davletshin AI, Matveeva AA, Poletaeva II, Evgen'ev MB, Garbuz DG. The role of molecular chaperones in the mechanisms of epileptogenesis. Cell Stress Chaperones 2023; 28:599-619. [PMID: 37755620 PMCID: PMC10746656 DOI: 10.1007/s12192-023-01378-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/30/2023] [Accepted: 09/08/2023] [Indexed: 09/28/2023] Open
Abstract
Epilepsy is a group of neurological diseases which requires significant economic costs for the treatment and care of patients. The central point of epileptogenesis stems from the failure of synaptic signal transmission mechanisms, leading to excessive synchronous excitation of neurons and characteristic epileptic electroencephalogram activity, in typical cases being manifested as seizures and loss of consciousness. The causes of epilepsy are extremely diverse, which is one of the reasons for the complexity of selecting a treatment regimen for each individual case and the high frequency of pharmacoresistant cases. Therefore, the search for new drugs and methods of epilepsy treatment requires an advanced study of the molecular mechanisms of epileptogenesis. In this regard, the investigation of molecular chaperones as potential mediators of epileptogenesis seems promising because the chaperones are involved in the processing and regulation of the activity of many key proteins directly responsible for the generation of abnormal neuronal excitation in epilepsy. In this review, we try to systematize current data on the role of molecular chaperones in epileptogenesis and discuss the prospects for the use of chemical modulators of various chaperone groups' activity as promising antiepileptic drugs.
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Affiliation(s)
| | - Anna A Matveeva
- Engelhardt Institute of Molecular Biology RAS, 119991, Moscow, Russia
- Moscow Institute of Physics and Technology, 141700, Dolgoprudny, Moscow Region, Russia
| | - Inga I Poletaeva
- Biology Department, Lomonosov Moscow State University, 119991, Moscow, Russia
| | | | - David G Garbuz
- Engelhardt Institute of Molecular Biology RAS, 119991, Moscow, Russia
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4
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Woo AM, Sontheimer H. Interactions between astrocytes and extracellular matrix structures contribute to neuroinflammation-associated epilepsy pathology. FRONTIERS IN MOLECULAR MEDICINE 2023; 3:1198021. [PMID: 39086689 PMCID: PMC11285605 DOI: 10.3389/fmmed.2023.1198021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/31/2023] [Indexed: 08/02/2024]
Abstract
Often considered the "housekeeping" cells of the brain, astrocytes have of late been rising to the forefront of neurodegenerative disorder research. Identified as crucial components of a healthy brain, it is undeniable that when astrocytes are dysfunctional, the entire brain is thrown into disarray. We offer epilepsy as a well-studied neurological disorder in which there is clear evidence of astrocyte contribution to diseases as evidenced across several different disease models, including mouse models of hippocampal sclerosis, trauma associated epilepsy, glioma-associated epilepsy, and beta-1 integrin knockout astrogliosis. In this review we suggest that astrocyte-driven neuroinflammation, which plays a large role in the pathology of epilepsy, is at least partially modulated by interactions with perineuronal nets (PNNs), highly structured formations of the extracellular matrix (ECM). These matrix structures affect synaptic placement, but also intrinsic neuronal properties such as membrane capacitance, as well as ion buffering in their immediate milieu all of which alters neuronal excitability. We propose that the interactions between PNNs and astrocytes contribute to the disease progression of epilepsy vis a vis neuroinflammation. Further investigation and alteration of these interactions to reduce the resultant neuroinflammation may serve as a potential therapeutic target that provides an alternative to the standard anti-seizure medications from which patients are so frequently unable to benefit.
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Affiliation(s)
- AnnaLin M. Woo
- Neuroscience Graduate Program, Neuroscience Department, University of Virginia, Charlottesville, VA, United States
| | - Harald Sontheimer
- Neuroscience Department, University of Virginia, Charlottesville, VA, United States
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5
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Faissner A. Low-density lipoprotein receptor-related protein-1 (LRP1) in the glial lineage modulates neuronal excitability. FRONTIERS IN NETWORK PHYSIOLOGY 2023; 3:1190240. [PMID: 37383546 PMCID: PMC10293750 DOI: 10.3389/fnetp.2023.1190240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/25/2023] [Indexed: 06/30/2023]
Abstract
The low-density lipoprotein related protein receptor 1 (LRP1), also known as CD91 or α-Macroglobulin-receptor, is a transmembrane receptor that interacts with more than 40 known ligands. It plays an important biological role as receptor of morphogens, extracellular matrix molecules, cytokines, proteases, protease inhibitors and pathogens. In the CNS, it has primarily been studied as a receptor and clearance agent of pathogenic factors such as Aβ-peptide and, lately, Tau protein that is relevant for tissue homeostasis and protection against neurodegenerative processes. Recently, it was found that LRP1 expresses the Lewis-X (Lex) carbohydrate motif and is expressed in the neural stem cell compartment. The removal of Lrp1 from the cortical radial glia compartment generates a strong phenotype with severe motor deficits, seizures and a reduced life span. The present review discusses approaches that have been taken to address the neurodevelopmental significance of LRP1 by creating novel, lineage-specific constitutive or conditional knockout mouse lines. Deficits in the stem cell compartment may be at the root of severe CNS pathologies.
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6
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Chakraborty P, Dey A, Gopalakrishnan AV, Swati K, Ojha S, Prakash A, Kumar D, Ambasta RK, Jha NK, Jha SK, Dewanjee S. Glutamatergic neurotransmission: A potential pharmacotherapeutic target for the treatment of cognitive disorders. Ageing Res Rev 2023; 85:101838. [PMID: 36610558 DOI: 10.1016/j.arr.2022.101838] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 12/27/2022] [Accepted: 12/29/2022] [Indexed: 01/06/2023]
Abstract
In the mammalian brain, glutamate is regarded to be the primary excitatory neurotransmitter due to its widespread distribution and wide range of metabolic functions. Glutamate plays key roles in regulating neurogenesis, synaptogenesis, neurite outgrowth, and neuron survival in the brain. Ionotropic and metabotropic glutamate receptors, neurotransmitters, neurotensin, neurosteroids, and others co-ordinately formulate a complex glutamatergic network in the brain that maintains optimal excitatory neurotransmission. Cognitive activities are potentially synchronized by the glutamatergic activities in the brain via restoring synaptic plasticity. Dysfunctional glutamate receptors and other glutamatergic components are responsible for the aberrant glutamatergic activity in the brain that cause cognitive impairments, loss of synaptic plasticity, and neuronal damage. Thus, controlling the brain's glutamatergic transmission and modifying glutamate receptor function could be a potential therapeutic strategy for cognitive disorders. Certain drugs that regulate glutamate receptor activities have shown therapeutic promise in improving cognitive functions in preclinical and clinical studies. However, several issues regarding precise functional information of glutamatergic activity are yet to be comprehensively understood. The present article discusses the scope of developing glutamatergic systems as prospective pharmacotherapeutic targets to treat cognitive disorders. Special attention has been given to recent developments, challenges, and future prospects.
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Affiliation(s)
- Pratik Chakraborty
- Advanced Pharmacognosy Research Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India
| | - Abhijit Dey
- Department of Life Sciences, Presidency University, Kolkata 700073, West Bengal, India
| | - Abilash Valsala Gopalakrishnan
- Department of Biomedical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu 632014, India
| | - Kumari Swati
- Department of Biotechnology, School of Life Science, Mahatma Gandhi Central University, Motihari, Bihar, India
| | - Shreesh Ojha
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Anand Prakash
- Department of Biotechnology, School of Life Science, Mahatma Gandhi Central University, Motihari, Bihar, India
| | - Dhruv Kumar
- School of Health Sciences & Technology, UPES University, Dehradun, Uttarakhand 248007, India
| | - Rashmi K Ambasta
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Delhi 110042, India
| | - Niraj Kumar Jha
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida 201310, UP, India; School of Bioengineering & Biosciences, Lovely Professional University, Phagwara, Punjab 144411, India.
| | - Saurabh Kumar Jha
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida 201310, UP, India; Department of Biotechnology Engineering and Food Technology, Chandigarh University, Mohali 140413, India; Department of Biotechnology, School of Applied & Life Sciences (SALS), Uttaranchal University, Dehradun 248007, India.
| | - Saikat Dewanjee
- Advanced Pharmacognosy Research Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
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7
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Alijanpour S, Miryounesi M, Ghafouri-Fard S. The role of excitatory amino acid transporter 2 (EAAT2) in epilepsy and other neurological disorders. Metab Brain Dis 2023; 38:1-16. [PMID: 36173507 DOI: 10.1007/s11011-022-01091-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 09/15/2022] [Indexed: 02/03/2023]
Abstract
Glutamate is the major excitatory neurotransmitter in the central nervous system (CNS). Excitatory amino acid transporters (EAATs) have important roles in the uptake of glutamate and termination of glutamatergic transmission. Up to now, five EAAT isoforms (EAAT1-5) have been identified in mammals. The main focus of this review is EAAT2. This protein has an important role in the pathoetiology of epilepsy. De novo dominant mutations, as well as inherited recessive mutation in this gene, have been associated with epilepsy. Moreover, dysregulation of this protein is implicated in a range of neurological diseases, namely amyotrophic lateral sclerosis, alzheimer's disease, parkinson's disease, schizophrenia, epilepsy, and autism. In this review, we summarize the role of EAAT2 in epilepsy and other neurological disorders, then provide an overview of the therapeutic modulation of this protein.
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Affiliation(s)
- Sahar Alijanpour
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Miryounesi
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soudeh Ghafouri-Fard
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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8
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Abram M, Jakubiec M, Reeb K, Cheng MH, Gedschold R, Rapacz A, Mogilski S, Socała K, Nieoczym D, Szafarz M, Latacz G, Szulczyk B, Kalinowska-Tłuścik J, Gawel K, Esguerra CV, Wyska E, Müller CE, Bahar I, Fontana ACK, Wlaź P, Kamiński RM, Kamiński K. Discovery of ( R)- N-Benzyl-2-(2,5-dioxopyrrolidin-1-yl)propanamide [ (R)-AS-1], a Novel Orally Bioavailable EAAT2 Modulator with Drug-like Properties and Potent Antiseizure Activity In Vivo. J Med Chem 2022; 65:11703-11725. [PMID: 35984707 PMCID: PMC9469208 DOI: 10.1021/acs.jmedchem.2c00534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
(R)-7 [(R)-AS-1] showed broad-spectrum antiseizure activity across in vivo mouse seizure models: maximal electroshock (MES), 6 Hz (32/44 mA), acute pentylenetetrazol (PTZ), and PTZ-kindling. A remarkable separation between antiseizure activity and CNS-related adverse effects was also observed. In vitro studies with primary glia cultures and COS-7 cells expressing the glutamate transporter EAAT2 showed enhancement of glutamate uptake, revealing a stereoselective positive allosteric modulator (PAM) effect, further supported by molecular docking simulations. (R)-7 [(R)-AS-1] was not active in EAAT1 and EAAT3 assays and did not show significant off-target activity, including interactions with targets reported for marketed antiseizure drugs, indicative of a novel and unprecedented mechanism of action. Both in vivo pharmacokinetic and in vitro absorption, distribution, metabolism, excretion, toxicity (ADME-Tox) profiles confirmed the favorable drug-like potential of the compound. Thus, (R)-7 [(R)-AS-1] may be considered as the first-in-class small-molecule PAM of EAAT2 with potential for further preclinical and clinical development in epilepsy and possibly other CNS disorders.
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Affiliation(s)
- Michał Abram
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688Krakow, Poland
| | - Marcin Jakubiec
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688Krakow, Poland
| | - Katelyn Reeb
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania19102, United States
| | - Mary Hongying Cheng
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania15213, United States
| | - Robin Gedschold
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical & Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, An der Immenburg 4, D-53121Bonn, Germany
| | - Anna Rapacz
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688Krakow, Poland
| | - Szczepan Mogilski
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688Krakow, Poland
| | - Katarzyna Socała
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033Lublin, Poland
| | - Dorota Nieoczym
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033Lublin, Poland
| | - Małgorzata Szafarz
- Department of Pharmacokinetics and Physical Pharmacy, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688Krakow, Poland
| | - Gniewomir Latacz
- Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688Krakow, Poland
| | - Bartłomiej Szulczyk
- Department of Pharmacodynamics, Centre for Preclinical Research and Technology, Medical University of Warsaw, Banacha 1B, 02-097Warsaw, Poland
| | - Justyna Kalinowska-Tłuścik
- Department of Crystal Chemistry and Crystal Physics, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387Krakow, Poland
| | - Kinga Gawel
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8B, 20-090Lublin, Poland
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349Oslo, Norway
| | - Elżbieta Wyska
- Department of Pharmacokinetics and Physical Pharmacy, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688Krakow, Poland
| | - Christa E Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical & Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, An der Immenburg 4, D-53121Bonn, Germany
| | - Ivet Bahar
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania15213, United States
| | - Andréia C K Fontana
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania19102, United States
| | - Piotr Wlaź
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033Lublin, Poland
| | - Rafał M Kamiński
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688Krakow, Poland
| | - Krzysztof Kamiński
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688Krakow, Poland
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9
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Salamone A, Terrone G, Di Sapia R, Balosso S, Ravizza T, Beltrame L, Craparotta I, Mannarino L, Cominesi SR, Rizzi M, Pauletti A, Marchini S, Porcu L, Zimmer TS, Aronica E, During M, Abrahams B, Kondo S, Nishi T, Vezzani A. Cholesterol 24-hydroxylase is a novel pharmacological target for anti-ictogenic and disease modification effects in epilepsy. Neurobiol Dis 2022; 173:105835. [PMID: 35932989 DOI: 10.1016/j.nbd.2022.105835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/15/2022] [Accepted: 07/30/2022] [Indexed: 10/16/2022] Open
Abstract
Therapies for epilepsy mainly provide symptomatic control of seizures since most of the available drugs do not target disease mechanisms. Moreover, about one-third of patients fail to achieve seizure control. To address the clinical need for disease-modifying therapies, research should focus on targets which permit interventions finely balanced between optimal efficacy and safety. One potential candidate is the brain-specific enzyme cholesterol 24-hydroxylase. This enzyme converts cholesterol to 24S-hydroxycholesterol, a metabolite which among its biological roles modulates neuronal functions relevant for hyperexcitability underlying seizures. To study the role of cholesterol 24-hydroxylase in epileptogenesis, we administered soticlestat (TAK-935/OV935), a potent and selective brain-penetrant inhibitor of the enzyme, during the early disease phase in a mouse model of acquired epilepsy using a clinically relevant dose. During soticlestat treatment, the onset of epilepsy was delayed and the number of ensuing seizures was decreased by about 3-fold compared to vehicle-treated mice, as assessed by EEG monitoring. Notably, the therapeutic effect was maintained 6.5 weeks after drug wash-out when seizure number was reduced by about 4-fold and their duration by 2-fold. Soticlestat-treated mice showed neuroprotection of hippocampal CA1 neurons and hilar mossy cells as assessed by post-mortem brain histology. High throughput RNA-sequencing of hippocampal neurons and glia in mice treated with soticlestat during epileptogenesis showed that inhibition of cholesterol 24-hydroxylase did not directly affect the epileptogenic transcriptional network, but rather modulated a non-overlapping set of genes that might oppose the pathogenic mechanisms of the disease. In human temporal lobe epileptic foci, we determined that cholesterol 24-hydroxylase expression trends higher in neurons, similarly to epileptic mice, while the enzyme is ectopically induced in astrocytes compared to control specimens. Soticlestat reduced significantly the number of spontaneous seizures in chronic epileptic mice when was administered during established epilepsy. Data show that cholesterol 24-hydroxylase contributes to spontaneous seizures and is involved in disease progression, thus it represents a novel target for chronic seizures inhibition and disease-modification therapy in epilepsy.
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Affiliation(s)
- Alessia Salamone
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Gaetano Terrone
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Rossella Di Sapia
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Silvia Balosso
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Teresa Ravizza
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Luca Beltrame
- Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Ilaria Craparotta
- Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Laura Mannarino
- Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Sara Raimondi Cominesi
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Massimo Rizzi
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Alberto Pauletti
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Sergio Marchini
- Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Luca Porcu
- Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy
| | - Till S Zimmer
- Department of Neuropathology, Amsterdam UMC, 1105 Amsterdam, the Netherlands
| | - Eleonora Aronica
- Department of Neuropathology, Amsterdam UMC, 1105 Amsterdam, the Netherlands; Stichting Epilepsie Instellingen Nederland (SEIN), 2103 Heemstede, the Netherlands
| | | | - Brett Abrahams
- Ovid Therapeutics, 10036 New York, NY, USA; Departments of Genetics and Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 10461 Bronx, USA
| | - Shinichi Kondo
- Takeda Pharmaceutical Company Limited, 251-8555 Fujisawa, Japan
| | - Toshiya Nishi
- Takeda Pharmaceutical Company Limited, 251-8555 Fujisawa, Japan
| | - Annamaria Vezzani
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milano, Italy.
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10
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Moradi F, Eslami F, Rahimi N, Koohfar A, Shayan M, Maadani M, Ghasemi M, Dehpour AR. Modafinil exerts anticonvulsive effects against lithium-pilocarpine-induced status epilepticus in rats: A role for tumor necrosis factor-α and nitric oxide signaling. Epilepsy Behav 2022; 130:108649. [PMID: 35344809 DOI: 10.1016/j.yebeh.2022.108649] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/24/2022] [Accepted: 02/24/2022] [Indexed: 11/24/2022]
Abstract
BACKGROUND Status epilepticus (SE) is a continuous episode of seizures which leads to hippocampal neurodegeneration, severe systemic inflammation, and extreme damage to the brain. Modafinil, a psychostimulant and wake-promoting agent, has exerted neuroprotective and anti-inflammatory effects in previous preclinical studies. The aim of this study was to assess effects of modafinil on the lithium-pilocarpine-induced SE rat model and to explore possible involvement of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) pathways in this regard. METHODS Status epilepticus was provoked by injection of lithium chloride (127 mg/kg, intraperitoneally [i.p]) and pilocarpine (60 mg/kg, i.p.) in rats. Animals received different modafinil doses (50, 75, 100, and 150 mg/kg, i.p.) and SE scores were documented over 3 hours of duration. Moreover, the role of the nitrergic pathway in the effects of modafinil was evaluated by injection of the non-selective NO synthase (NOS) inhibitor L-NG-Nitro arginine methyl ester (L-NAME, 10 mg/kg, i.p.), the selective neuronal NOS inhibitor 7-nitroindazole (30 mg/kg, i.p.), and the selective inducible NOS inhibitor aminoguanidine (100 mg/kg, i.p.) 15 min before saline/vehicle or modafinil. The ELISA method was used to quantify TNF-α and NO metabolite levels in the isolated hippocampus. RESULTS Modafinil at 100 mg/kg significantly decreased SE scores (P < 0.01). Pre-treatment with L-NAME, 7-nitroindazole, and aminoguanidine significantly reversed the anticonvulsive effects of modafinil. Status epilepticus-induced animals showed significantly higher NO metabolite and TNF-α levels in their hippocampal tissues, an effect that was reversed by modafinil (100 mg/kg, i.p.) treatment. Administration of NOS inhibitors resulted in excessive NO level reduction but an escalation of TNF-α level in modafinil-treated SE-animals. CONCLUSION Our study revealed anticonvulsive effects of modafinil in the lithium-pilocarpine-induced SE rat model via possible involvement of TNF-α and nitrergic pathways.
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Affiliation(s)
- Farid Moradi
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Faezeh Eslami
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Nastaran Rahimi
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Amirhossein Koohfar
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Shayan
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahshad Maadani
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Ghasemi
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Ahmad Reza Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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11
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Hayatdavoudi P, Hosseini M, Hajali V, Hosseini A, Rajabian A. The role of astrocytes in epileptic disorders. Physiol Rep 2022; 10:e15239. [PMID: 35343625 PMCID: PMC8958496 DOI: 10.14814/phy2.15239] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 02/27/2022] [Accepted: 03/09/2022] [Indexed: 04/17/2023] Open
Abstract
Epilepsy affects about 1% of the population and approximately 30% of epileptic patients are resistant to current antiepileptic drugs. As a hallmark in epileptic tissue, many of the epileptic patients show changes in glia morphology and function. There are characteristic changes in different types of glia in different epilepsy models. Some of these changes such as astrogliosis are enough to provoke epileptic seizures. Astrogliosis is well known in mesial temporal lobe epilepsy (MTLE), the most common form of refractory epilepsy. A better understanding of astrocytes alterations could lead to novel and efficient pharmacological approaches for epilepsy. In this review, we present the alterations of astrocyte morphology and function and present some instances of targeting astrocytes in seizure and epilepsy.
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Affiliation(s)
- Parichehr Hayatdavoudi
- Applied Biomedical Research CenterMashhad University of Medical SciencesMashhadIran
- Department of PhysiologyFaculty of MedicineMashhad University of Medical SciencesMashhadIran
| | - Mahmoud Hosseini
- Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research CenterMashhad University of Medical SciencesMashhadIran
| | - Vahid Hajali
- Department of NeuroscienceFaculty of MedicineMashhad University of Medical SciencesMashhadIran
| | - Azar Hosseini
- Pharmacological Research Center of Medicinal PlantsMashhad University of Medical SciencesMashhadIran
- Department of PharmacologyFaculty of MedicineMashhad University of Medical SciencesMashhadIran
| | - Arezoo Rajabian
- Department of Internal MedicineFaculty of MedicineMashhad University of Medical SciencesMashhadIran
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12
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Green JL, Dos Santos WF, Fontana ACK. Role of glutamate excitotoxicity and glutamate transporter EAAT2 in epilepsy: Opportunities for novel therapeutics development. Biochem Pharmacol 2021; 193:114786. [PMID: 34571003 DOI: 10.1016/j.bcp.2021.114786] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 12/21/2022]
Abstract
Epilepsy is a complex neurological syndrome characterized by seizures resulting from neuronal hyperexcitability and sudden and synchronized bursts of electrical discharges. Impaired astrocyte function that results in glutamate excitotoxicity has been recognized to play a key role in the pathogenesis of epilepsy. While there are 26 drugs marketed as anti-epileptic drugs no current treatments are disease modifying as they only suppress seizures rather than the development and progression of epilepsy. Excitatory amino acid transporters (EAATs) are critical for maintaining low extracellular glutamate concentrations and preventing excitotoxicity. When extracellular glutamate concentrations rise to abnormal levels, glutamate receptor overactivation and the subsequent excessive influx of calcium into the post-synaptic neuron can trigger cell death pathways. In this review we discuss targeting EAAT2, the predominant glutamate transporter in the CNS, as a promising approach for developing therapies for epilepsy. EAAT2 upregulation via transcriptional and translational regulation has proven successful in vivo in reducing spontaneous recurrent seizures and offering neuroprotective effects. Another approach to regulate EAAT2 activity is through positive allosteric modulation (PAM). Novel PAMs of EAAT2 have recently been identified and are under development, representing a promising approach for the advance of novel therapeutics for epilepsy.
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Affiliation(s)
- Jennifer Leigh Green
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, 19102, United States
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13
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Peterson AR, Garcia TA, Cullion K, Tiwari-Woodruff SK, Pedapati EV, Binder DK. Targeted overexpression of glutamate transporter-1 reduces seizures and attenuates pathological changes in a mouse model of epilepsy. Neurobiol Dis 2021; 157:105443. [PMID: 34246771 DOI: 10.1016/j.nbd.2021.105443] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 01/06/2023] Open
Abstract
Astrocytic glutamate transporters are crucial for glutamate homeostasis in the brain, and dysregulation of these transporters can contribute to the development of epilepsy. Glutamate transporter-1 (GLT-1) is responsible for the majority of glutamate uptake in the dorsal forebrain and has been shown to be reduced at epileptic foci in patients and preclinical models of temporal lobe epilepsy (TLE). Current antiepileptic drugs (AEDs) work primarily by targeting neurons directly through suppression of excitatory neurotransmission or enhancement of inhibitory neurotransmission, which can lead to both behavioral and psychiatric side effects. This study investigates the therapeutic capacity of astrocyte-specific AAV-mediated GLT-1 expression in the intrahippocampal kainic acid (IHKA) model of TLE. In this study, we used Western blot analysis, immunohistochemistry, and long-term-video EEG monitoring to demonstrate that cell-type-specific upregulation of GLT-1 in astrocytes is neuroprotective at early time points during epileptogenesis, reduces seizure frequency and total time spent in seizures, and eliminates large behavioral seizures in the IHKA model of epilepsy. Our findings suggest that targeting glutamate uptake is a promising therapeutic strategy for the treatment of epilepsy.
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Affiliation(s)
- Allison R Peterson
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, School of Medicine, University of California, Riverside, CA, USA
| | - Terese A Garcia
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, School of Medicine, University of California, Riverside, CA, USA
| | - Kyle Cullion
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Seema K Tiwari-Woodruff
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, School of Medicine, University of California, Riverside, CA, USA
| | - Ernest V Pedapati
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Devin K Binder
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, School of Medicine, University of California, Riverside, CA, USA.
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14
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Zaitsev АV, Amakhin DV, Dyomina AV, Zakharova MV, Ergina JL, Postnikova TY, Diespirov GP, Magazanik LG. Synaptic Dysfunction in Epilepsy. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s002209302103008x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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15
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Dejakaisaya H, Kwan P, Jones NC. Astrocyte and glutamate involvement in the pathogenesis of epilepsy in Alzheimer's disease. Epilepsia 2021; 62:1485-1493. [PMID: 33971019 DOI: 10.1111/epi.16918] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) can increase the risk of epilepsy by up to 10-fold compared to healthy age-matched controls. However, the pathological mechanisms that underlie this increased risk are poorly understood. Because disruption in brain glutamate homeostasis has been implicated in both AD and epilepsy, this might play a mechanistic role in the pathogenesis of epilepsy in AD. Prior to the formation of amyloid beta (Aβ) plaques, the brain can undergo pathological changes as a result of increased production of amyloid precursor protein (APP) and Aβ oligomers. Impairments in the glutamate uptake ability of astrocytes due to astrogliosis are hypothesized to be an early event occurring before Aβ plaque formation. Astrogliosis may increase the susceptibility to epileptogenesis of the brain via accumulation of extracellular glutamate and resulting excitotoxicity. Here we hypothesize that Aβ oligomers and proinflammatory cytokines can cause astrogliosis and accumulation of extracellular glutamate, which then contribute to the pathogenesis of epilepsy in AD. In this review article, we consider the evidence supporting a potential role of dysfunction of the glutamate-glutamine cycle and the astrocyte in the pathogenesis of epilepsy in AD.
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Affiliation(s)
- Hattapark Dejakaisaya
- Department of Neuroscience, Central Clinical School, The Alfred Hospital, Monash University, Melbourne, Vic., Australia.,Faculty of Medicine and Public Health, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Patrick Kwan
- Department of Neuroscience, Central Clinical School, The Alfred Hospital, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Vic., Australia
| | - Nigel C Jones
- Department of Neuroscience, Central Clinical School, The Alfred Hospital, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Vic., Australia
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16
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Angiocentric glioma-associated seizures: The possible role of EATT2, pyruvate carboxylase and glutamine synthetase. Seizure 2021; 86:152-154. [PMID: 33621827 DOI: 10.1016/j.seizure.2021.02.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Our purpose was to better understand the pathogenesis of seizures associated with angiocentric glioma. Angiocentric glioma is an indolent and rare low-grade glioma. Its typical clinical presentation is with epileptic seizures. The pathogenesis of tumor-associated seizures is poorly understood. Among the possible pathomechanisms, the increased neurotoxic concentrations of the glutamate has been proposed. Glutamate transporters, pyruvate carboxylase and glutamine synthetase are involved in maintaining the physiological concentration of glutamate in the inter synaptic spaces. METHODS We evaluated the immunohistochemical expression of EAAT2 (the most important glutamate transporter), pyruvate carboxylase and glutamine synthetase in 17 angiocentric gliomas. RESULTS EAAT2 was never expressed (0%) in the neoplastic cells in none of the cases studied. Pyruvate carboxylase was expressed in the cytoplasm of the neoplastic cells in 16/17 cases (94 %). Glutamine synthetase was expressed in the cytoplasm of the neoplastic cells in 15/17 cases (88 %). CONCLUSION The net result of this enzymatic expression, in particular considering the loss of EAAT2, could be an increased glutamate concentration in the synaptic clef, which might increase local network excitability initially involving intratumoral neurons. The observation that the angiocentric glioma-associated epilepsy might be at least in part related to EAAT2 deficiency opens up interesting therapeutic perspectives.
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17
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Sears SM, Hewett SJ. Influence of glutamate and GABA transport on brain excitatory/inhibitory balance. Exp Biol Med (Maywood) 2021; 246:1069-1083. [PMID: 33554649 DOI: 10.1177/1535370221989263] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
An optimally functional brain requires both excitatory and inhibitory inputs that are regulated and balanced. A perturbation in the excitatory/inhibitory balance-as is the case in some neurological disorders/diseases (e.g. traumatic brain injury Alzheimer's disease, stroke, epilepsy and substance abuse) and disorders of development (e.g. schizophrenia, Rhett syndrome and autism spectrum disorder)-leads to dysfunctional signaling, which can result in impaired cognitive and motor function, if not frank neuronal injury. At the cellular level, transmission of glutamate and GABA, the principle excitatory and inhibitory neurotransmitters in the central nervous system control excitatory/inhibitory balance. Herein, we review the synthesis, release, and signaling of GABA and glutamate followed by a focused discussion on the importance of their transport systems to the maintenance of excitatory/inhibitory balance.
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Affiliation(s)
- Sheila Ms Sears
- Department of Biology, Program in Neuroscience, 2029Syracuse University, Syracuse, NY 13244, USA
| | - Sandra J Hewett
- Department of Biology, Program in Neuroscience, 2029Syracuse University, Syracuse, NY 13244, USA
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18
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Juvale IIA, Che Has AT. Possible interplay between the theories of pharmacoresistant epilepsy. Eur J Neurosci 2020; 53:1998-2026. [PMID: 33306252 DOI: 10.1111/ejn.15079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/22/2020] [Accepted: 12/04/2020] [Indexed: 02/06/2023]
Abstract
Epilepsy is one of the oldest known neurological disorders and is characterized by recurrent seizure activity. It has a high incidence rate, affecting a broad demographic in both developed and developing countries. Comorbid conditions are frequent in patients with epilepsy and have detrimental effects on their quality of life. Current management options for epilepsy include the use of anti-epileptic drugs, surgery, or a ketogenic diet. However, more than 30% of patients diagnosed with epilepsy exhibit drug resistance to anti-epileptic drugs. Further, surgery and ketogenic diets do little to alleviate the symptoms of patients with pharmacoresistant epilepsy. Thus, there is an urgent need to understand the underlying mechanisms of pharmacoresistant epilepsy to design newer and more effective anti-epileptic drugs. Several theories of pharmacoresistant epilepsy have been suggested over the years, the most common being the gene variant hypothesis, network hypothesis, multidrug transporter hypothesis, and target hypothesis. In our review, we discuss the main theories of pharmacoresistant epilepsy and highlight a possible interconnection between their mechanisms that could lead to the development of novel therapies for pharmacoresistant epilepsy.
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Affiliation(s)
- Iman Imtiyaz Ahmed Juvale
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Ahmad Tarmizi Che Has
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
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19
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Neurobiology, Functions, and Relevance of Excitatory Amino Acid Transporters (EAATs) to Treatment of Refractory Epilepsy. CNS Drugs 2020; 34:1089-1103. [PMID: 32926322 DOI: 10.1007/s40263-020-00764-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Epilepsy is one of the most prevalent and devastating neurological disorders characterized by episodes of unusual sensations, loss of awareness, and reoccurring seizures. The frequency and intensity of epileptic fits can vary to a great degree, with almost a third of all cases resistant to available therapies. At present, there is a major unmet need for effective and specific therapeutic intervention. Impairments of the exquisite balance between excitatory and inhibitory synaptic processes in the brain are considered key in the onset and pathophysiology of the disease. As the primary excitatory neurotransmitter in the central nervous system, glutamate has been implicated in the process, with the glutamatergic system holding center stage in the pathobiology as well as in developing disease-modifying therapies. Emerging data pinpoint impairments of glutamate clearance as one of the key causative factors in drug-resistant disease forms. Reinstatement of glutamate homeostasis using pharmacological and genetic modulation of glutamate clearance is therefore considered to be of major translational relevance. In this article, we review the neurobiological and clinical evidence suggesting complex aberrations in the activity and functions of excitatory amino acid transporters (EAATs) in epilepsy, with knock-on effects on glutamate homeostasis as a leading cause for the development of refractory forms. We consider the emerging data on pharmacological and genetic manipulations of EAATs, with reference to seizures and glutamate dyshomeostasis, and review their fundamental and translational relevance. We discuss the most recent advances in the EAATs research in human and animal models, along with numerous questions that remain open for debate and critical appraisal. Contrary to the widely held view on EAATs as a promising therapeutic target for management of refractory epilepsy as well as other neurological and psychiatric conditions related to glutamatergic hyperactivity and glutamate-induced cytotoxicity, we stress that the true relevance of EAAT2 as a target for medical intervention remains to be fully appreciated and verified. Despite decades of research, the emerging properties and functional characteristics of glutamate transporters and their relationship with neurophysiological and behavioral correlates of epilepsy challenge the current perception of this disease and fit unambiguously in neither EAATs functional deficit nor in reversal models. We stress the pressing need for new approaches and models for research and restoration of the physiological activity of glutamate transporters and synaptic transmission to achieve much needed therapeutic effects. The complex mechanism of EAATs regulation by multiple factors, including changes in the electrochemical environment and ionic gradients related to epileptic hyperactivity, impose major therapeutic challenges. As a final note, we consider the evolving views and present a cautious perspective on the key areas of future progress in the field towards better management and treatment of refractory disease forms.
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20
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Dyomina AV, Zubareva OE, Smolensky IV, Vasilev DS, Zakharova MV, Kovalenko AA, Schwarz AP, Ischenko AM, Zaitsev AV. Anakinra Reduces Epileptogenesis, Provides Neuroprotection, and Attenuates Behavioral Impairments in Rats in the Lithium-Pilocarpine Model of Epilepsy. Pharmaceuticals (Basel) 2020; 13:ph13110340. [PMID: 33113868 PMCID: PMC7692198 DOI: 10.3390/ph13110340] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/18/2020] [Accepted: 10/22/2020] [Indexed: 12/17/2022] Open
Abstract
Temporal lobe epilepsy is a widespread chronic disorder that manifests as spontaneous seizures and is often characterized by refractoriness to drug treatment. Temporal lobe epilepsy can be caused by a primary brain injury; therefore, the prevention of epileptogenesis after a primary event is considered one of the best treatment options. However, a preventive treatment for epilepsy still does not exist. Neuroinflammation is directly involved in epileptogenesis and neurodegeneration, leading to the epileptic condition and cognitive decline. In the present study, we aimed to clarify the effect of treatment with a recombinant form of the Interleukin-1 receptor antagonist (anakinra) on epileptogenesis and behavioral impairments in rats using the lithium–pilocarpine model. We found that anakinra administration during the latent phase of the model significantly suppressed the duration and frequency of spontaneous recurrent seizures in the chronic phase. Moreover, anakinra administration prevented some behavioral impairments, including motor hyperactivity and disturbances in social interactions, during both the latent and chronic periods. Histological analysis revealed that anakinra administration decreased neuronal loss in the CA1 and CA3 areas of the hippocampus but did not prevent astro- and microgliosis. The treatment increased the expression level of the solute carrier family 1 member 2 gene (Slc1a2, encoding excitatory amino acid transporter 2 (EAAT2)) in the hippocampus, potentially leading to a neuroprotective effect. However, the increased gene expression of proinflammatory cytokine genes (Interleukin-1β (Il1b) and tumor necrosis factor α (Tnfa)) and astroglial marker genes (glial fibrillary acidic protein (Gfap) and inositol 1,4,5-trisphosphate receptor type 2 (Itpr2)) in experimental rats was not affected by anakinra treatment. Thus, our data demonstrate that the administration of anakinra during epileptogenesis has some beneficial disease-modifying effects.
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Affiliation(s)
- Alexandra V. Dyomina
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (A.V.D.); (O.E.Z.); (I.V.S.); (D.S.V.) (M.V.Z.); (A.A.K.); (A.P.S.)
| | - Olga E. Zubareva
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (A.V.D.); (O.E.Z.); (I.V.S.); (D.S.V.) (M.V.Z.); (A.A.K.); (A.P.S.)
| | - Ilya V. Smolensky
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (A.V.D.); (O.E.Z.); (I.V.S.); (D.S.V.) (M.V.Z.); (A.A.K.); (A.P.S.)
| | - Dmitry S. Vasilev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (A.V.D.); (O.E.Z.); (I.V.S.); (D.S.V.) (M.V.Z.); (A.A.K.); (A.P.S.)
| | - Maria V. Zakharova
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (A.V.D.); (O.E.Z.); (I.V.S.); (D.S.V.) (M.V.Z.); (A.A.K.); (A.P.S.)
| | - Anna A. Kovalenko
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (A.V.D.); (O.E.Z.); (I.V.S.); (D.S.V.) (M.V.Z.); (A.A.K.); (A.P.S.)
| | - Alexander P. Schwarz
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (A.V.D.); (O.E.Z.); (I.V.S.); (D.S.V.) (M.V.Z.); (A.A.K.); (A.P.S.)
| | - Alexander M. Ischenko
- Research Institute of Highly Pure Biopreparations, Federal Medical-Biological Agency, 7, Pudozhskaya Street, 197110 Saint Petersburg, Russia;
| | - Aleksey V. Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (A.V.D.); (O.E.Z.); (I.V.S.); (D.S.V.) (M.V.Z.); (A.A.K.); (A.P.S.)
- Correspondence: ; Tel.: +7-812-552-3058
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Kim YS, Choi J, Yoon BE. Neuron-Glia Interactions in Neurodevelopmental Disorders. Cells 2020; 9:cells9102176. [PMID: 32992620 PMCID: PMC7601502 DOI: 10.3390/cells9102176] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 12/12/2022] Open
Abstract
Recent studies have revealed synaptic dysfunction to be a hallmark of various psychiatric diseases, and that glial cells participate in synapse formation, development, and plasticity. Glial cells contribute to neuroinflammation and synaptic homeostasis, the latter being essential for maintaining the physiological function of the central nervous system (CNS). In particular, glial cells undergo gliotransmission and regulate neuronal activity in tripartite synapses via ion channels (gap junction hemichannel, volume regulated anion channel, and bestrophin-1), receptors (for neurotransmitters and cytokines), or transporters (GLT-1, GLAST, and GATs) that are expressed on glial cell membranes. In this review, we propose that dysfunction in neuron-glia interactions may contribute to the pathogenesis of neurodevelopmental disorders. Understanding the mechanisms of neuron-glia interaction for synapse formation and maturation will contribute to the development of novel therapeutic targets of neurodevelopmental disorders.
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Affiliation(s)
- Yoo Sung Kim
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea; (Y.S.K.); (J.C.)
| | - Juwon Choi
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea; (Y.S.K.); (J.C.)
| | - Bo-Eun Yoon
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea; (Y.S.K.); (J.C.)
- Department of Nanobiomedical science, Dankook University, Cheonan 31116, Korea
- Correspondence: ; Tel.: +82-41-529-6085
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22
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Peterson AR, Binder DK. Astrocyte Glutamate Uptake and Signaling as Novel Targets for Antiepileptogenic Therapy. Front Neurol 2020; 11:1006. [PMID: 33013665 PMCID: PMC7505989 DOI: 10.3389/fneur.2020.01006] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/30/2020] [Indexed: 12/14/2022] Open
Abstract
Astrocytes regulate and respond to extracellular glutamate levels in the central nervous system (CNS) via the Na+-dependent glutamate transporters glutamate transporter-1 (GLT-1) and glutamate aspartate transporter (GLAST) and the metabotropic glutamate receptors (mGluR) 3 and mGluR5. Both impaired astrocytic glutamate clearance and changes in metabotropic glutamate signaling could contribute to the development of epilepsy. Dysregulation of astrocytic glutamate transporters, GLT-1 and GLAST, is a common finding across patients and preclinical seizure models. Astrocytic metabotropic glutamate receptors, particularly mGluR5, have been shown to be dysregulated in both humans and animal models of temporal lobe epilepsy (TLE). In this review, we synthesize the available evidence regarding astrocytic glutamate homeostasis and astrocytic mGluRs in the development of epilepsy. Modulation of astrocyte glutamate uptake and/or mGluR activation could lead to novel glial therapeutics for epilepsy.
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Affiliation(s)
- Allison R Peterson
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Devin K Binder
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, School of Medicine, University of California, Riverside, Riverside, CA, United States
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Stevenson R, Samokhina E, Rossetti I, Morley JW, Buskila Y. Neuromodulation of Glial Function During Neurodegeneration. Front Cell Neurosci 2020; 14:278. [PMID: 32973460 PMCID: PMC7473408 DOI: 10.3389/fncel.2020.00278] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022] Open
Abstract
Glia, a non-excitable cell type once considered merely as the connective tissue between neurons, is nowadays acknowledged for its essential contribution to multiple physiological processes including learning, memory formation, excitability, synaptic plasticity, ion homeostasis, and energy metabolism. Moreover, as glia are key players in the brain immune system and provide structural and nutritional support for neurons, they are intimately involved in multiple neurological disorders. Recent advances have demonstrated that glial cells, specifically microglia and astroglia, are involved in several neurodegenerative diseases including Amyotrophic lateral sclerosis (ALS), Epilepsy, Parkinson's disease (PD), Alzheimer's disease (AD), and frontotemporal dementia (FTD). While there is compelling evidence for glial modulation of synaptic formation and regulation that affect neuronal signal processing and activity, in this manuscript we will review recent findings on neuronal activity that affect glial function, specifically during neurodegenerative disorders. We will discuss the nature of each glial malfunction, its specificity to each disorder, overall contribution to the disease progression and assess its potential as a future therapeutic target.
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Affiliation(s)
- Rebecca Stevenson
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Evgeniia Samokhina
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Ilaria Rossetti
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - John W. Morley
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Yossi Buskila
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
- International Centre for Neuromorphic Systems, The MARCS Institute for Brain, Behaviour and Development, Penrith, NSW, Australia
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24
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Bres EE, Safina D, Müller J, Bedner P, Yang H, Helluy X, Shchyglo O, Jansen S, Mark MD, Esser A, Steinhäuser C, Herlitze S, Pietrzik CU, Sirko S, Manahan-Vaughan D, Faissner A. Lipoprotein receptor loss in forebrain radial glia results in neurological deficits and severe seizures. Glia 2020; 68:2517-2549. [PMID: 32579270 DOI: 10.1002/glia.23869] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 05/19/2020] [Accepted: 05/22/2020] [Indexed: 02/06/2023]
Abstract
The Alzheimer disease-associated multifunctional low-density lipoprotein receptor-related protein-1 is expressed in the brain. Recent studies uncovered a role of this receptor for the appropriate functioning of neural stem cells, oligodendrocytes, and neurons. The constitutive knock-out (KO) of the receptor is embryonically lethal. To unravel the receptors' role in the developing brain we generated a mouse mutant by specifically targeting radial glia stem cells of the dorsal telencephalon. The low-density lipoprotein receptor-related protein-1 lineage-restricted KO female and male mice, in contrast to available models, developed a severe neurological phenotype with generalized seizures during early postnatal development. The mechanism leading to a buildup of hyperexcitability and emergence of seizures was traced to a failure in adequate astrocyte development and deteriorated postsynaptic density integrity. The detected impairments in the astrocytic lineage: precocious maturation, reactive gliosis, abolished tissue plasminogen activator uptake, and loss of functionality emphasize the importance of this glial cell type for synaptic signaling in the developing brain. Together, the obtained results highlight the relevance of astrocytic low-density lipoprotein receptor-related protein-1 for glutamatergic signaling in the context of neuron-glia interactions and stage this receptor as a contributing factor for epilepsy.
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Affiliation(s)
- Ewa E Bres
- Department of Cell Morphology and Molecular Neurobiology, Ruhr University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Dina Safina
- Department of Cell Morphology and Molecular Neurobiology, Ruhr University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Julia Müller
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Peter Bedner
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Honghong Yang
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Xavier Helluy
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany.,Department of Psychology, Institute of Cognitive Neuroscience, Biopsychology, Ruhr University Bochum, Bochum, Germany
| | - Olena Shchyglo
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Stephan Jansen
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Melanie D Mark
- Behavioral Neuroscience, Ruhr University Bochum, Bochum, Germany
| | | | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Stefan Herlitze
- Department of General Zoology and Neurobiology, Ruhr University Bochum, Bochum, Germany
| | - Claus U Pietrzik
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Swetlana Sirko
- Department of Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians University, Planegg-Martinsried, Germany.,Institute for Stem Cell Research, Helmholtz Zentrum Munich, Neuherberg, Germany
| | | | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Ruhr University Bochum, Bochum, Germany
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25
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Armada-Moreira A, Gomes JI, Pina CC, Savchak OK, Gonçalves-Ribeiro J, Rei N, Pinto S, Morais TP, Martins RS, Ribeiro FF, Sebastião AM, Crunelli V, Vaz SH. Going the Extra (Synaptic) Mile: Excitotoxicity as the Road Toward Neurodegenerative Diseases. Front Cell Neurosci 2020; 14:90. [PMID: 32390802 PMCID: PMC7194075 DOI: 10.3389/fncel.2020.00090] [Citation(s) in RCA: 145] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/26/2020] [Indexed: 12/13/2022] Open
Abstract
Excitotoxicity is a phenomenon that describes the toxic actions of excitatory neurotransmitters, primarily glutamate, where the exacerbated or prolonged activation of glutamate receptors starts a cascade of neurotoxicity that ultimately leads to the loss of neuronal function and cell death. In this process, the shift between normal physiological function and excitotoxicity is largely controlled by astrocytes since they can control the levels of glutamate on the synaptic cleft. This control is achieved through glutamate clearance from the synaptic cleft and its underlying recycling through the glutamate-glutamine cycle. The molecular mechanism that triggers excitotoxicity involves alterations in glutamate and calcium metabolism, dysfunction of glutamate transporters, and malfunction of glutamate receptors, particularly N-methyl-D-aspartic acid receptors (NMDAR). On the other hand, excitotoxicity can be regarded as a consequence of other cellular phenomena, such as mitochondrial dysfunction, physical neuronal damage, and oxidative stress. Regardless, it is known that the excessive activation of NMDAR results in the sustained influx of calcium into neurons and leads to several deleterious consequences, including mitochondrial dysfunction, reactive oxygen species (ROS) overproduction, impairment of calcium buffering, the release of pro-apoptotic factors, among others, that inevitably contribute to neuronal loss. A large body of evidence implicates NMDAR-mediated excitotoxicity as a central mechanism in the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), and epilepsy. In this review article, we explore different causes and consequences of excitotoxicity, discuss the involvement of NMDAR-mediated excitotoxicity and its downstream effects on several neurodegenerative disorders, and identify possible strategies to study new aspects of these diseases that may lead to the discovery of new therapeutic approaches. With the understanding that excitotoxicity is a common denominator in neurodegenerative diseases and other disorders, a new perspective on therapy can be considered, where the targets are not specific symptoms, but the underlying cellular phenomena of the disease.
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Affiliation(s)
- Adam Armada-Moreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
| | - Joana I. Gomes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Carolina Campos Pina
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Oksana K. Savchak
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Joana Gonçalves-Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Nádia Rei
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Sara Pinto
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Tatiana P. Morais
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, United Kingdom
| | - Robertta Silva Martins
- Laboratório de Neurofarmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Filipa F. Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Ana M. Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, United Kingdom
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Sandra H. Vaz
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
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Gallagher M. The System xc- Cystine/Glutamate Antiporter: An Exciting Target for Antiepileptogenic Therapy? Epilepsy Curr 2020; 20:39-42. [PMID: 31893940 PMCID: PMC7020536 DOI: 10.1177/1535759719891983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Anticonvulsant and Antiepileptogenic Effects of System xc-Inactivation in Chronic Epilepsy Models Leclercq K, Liefferinge JV, Albertini G, et al. Epilepsia. 2019. doi:10.1111/epi.16055. Epub ahead of print. PMID: 31179549 Objective: The cystine/glutamate antiporter system xc- could represent a new target for antiepileptogenic treatments due to its crucial roles in glutamate homeostasis and neuroinflammation. To demonstrate this, we compared epilepsy development and seizure susceptibility in xCT knockout mice (xCT−/−) and in littermate controls (xCT+/+) in different chronic models of epilepsy. Methods: Mice were surgically implanted with electrodes in the basolateral amygdala and chronically stimulated to develop self-sustained status epilepticus (SSSE); continuous video-electroencephalography monitoring was performed for 28 days after SE and hippocampal histopathology was assessed. Corneal kindling was induced by twice daily electrical stimulation at 6 Hz and maintenance of the fully kindled state was evaluated. Next, messenger RNA (mRNA) and protein levels of xCT and of the proteins involved in the phosphoinositide 3-kinase (PI3K)/Akt/glycogen synthase kinase 3β (GSK-3β)/eukaryotic initiation factor 2α (eIF2α)/activating transcription factor 4 (ATF4) signaling pathway were measured at different time points during epileptogenesis in Naval Medical Research Institute mice treated with pilocarpine. Finally, the anticonvulsant effect of sulfasalazine (SAS), a nonselective system xc-inhibitor, was assessed against 6 Hz-evoked seizures in pilocarpine-treated mice. Results: In the SSSE model, xCT−/− mice displayed a significant delayed epileptogenesis, a reduced number of spontaneous recurrent seizures, and less pronounced astrocytic and microglial activation. Moreover, xCT−/− mice showed reduced seizure severity during 6 Hz kindling development and a lower incidence of generalized seizures during the maintenance of the fully kindled state. In pilocarpine-treated mice, protein levels of the PI3K/Akt/GSK-3β/eIF2α/ATF4 pathway were increased during the chronic phase of the model, consistent with previous findings in the hippocampus of patients with epilepsy. Finally, repeated administration of SAS protected pilocarpine-treated mice against acute 6 Hz seizure induction, in contrast to sham controls, in which system xc- is not activated. Significance: Inhibition of system xc- could be an attractive target for the development of new therapies with a potential for disease modification in epilepsy. Decreased Epileptogenesis in Mice Lacking the System xc—Transporter Occurs in Association With a Reduction in AMPA Receptor Subunit GluA1 Sears SMS, Hewett JA, Hewett SJ. Epilepsia Open. 2019;4(1):133-143. doi:10.1002/epi4.12307. eCollection 2019 March. PMID: 30868123. Objective: Although the cystine/glutamate antiporter system xc—(Sxc-) plays a permissive role in glioma-associated seizures, its contribution to other acquired epilepsies has not been determined. As such, the present study investigates whether and how Sxc—contributes to the pentylenetetrazole (PTZ) chemical kindling model of epileptogenesis. Methods: Male Sxc—null (sut/sut) mice and their wild-type littermates were administered PTZ (intraperitoneal) daily for up to 21 days (kindling paradigm). Seizure severity was scored on a 5-point behavioral scale. Mossy fiber sprouting, cellular degeneration, and Sxc—light chain (xCT) messenger RNA (mRNA) were explored using Timm staining, thionin staining, and real-time quantitative polymerase chain reaction, respectively. Levels of reduced and oxidized glutathione and cysteine were determined via high-performance liquid chromatography. Plasma membrane protein levels of glutamate and γ-aminobutyric acid (GABA) receptor subunits as well as the K+/Cl− co-transporter KCC2 were quantified via Western blot analysis. Results: Repeated administration of PTZ produced chemical kindling in only 50% of Sxc—null mice as compared to 82% of wild-type littermate control mice. Kindling did not result in any changes in xCT mRNA levels assessed in wild-type mice. No cellular degeneration or mossy fiber sprouting was discernible in either genotype. Except for a small, but significant, decrease in oxidized cysteine in the hippocampus, no other change in measured redox couples was determined in Sxc - null mice. Cortical levels of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA1 were decreased in Sxc - null mice as compared to wild-type littermates, whereas all other proteins tested showed no difference between genotypes. Significance: This study provides the first evidence that Sxc-signaling contributes to epileptogenesis in the PTZ kindling model of acquired epilepsy. Further data indicate that a reduction in AMPA receptor signaling could underlie the resistance to PTZ kindling uncovered in Sxc-null mice.
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27
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Patel DC, Tewari BP, Chaunsali L, Sontheimer H. Neuron-glia interactions in the pathophysiology of epilepsy. Nat Rev Neurosci 2019; 20:282-297. [PMID: 30792501 DOI: 10.1038/s41583-019-0126-4] [Citation(s) in RCA: 232] [Impact Index Per Article: 46.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Epilepsy is a neurological disorder afflicting ~65 million people worldwide. It is caused by aberrant synchronized firing of populations of neurons primarily due to imbalance between excitatory and inhibitory neurotransmission. Hence, the historical focus of epilepsy research has been neurocentric. However, the past two decades have enjoyed an explosion of research into the role of glia in supporting and modulating neuronal activity, providing compelling evidence of glial involvement in the pathophysiology of epilepsy. The mechanisms by which glia, particularly astrocytes and microglia, may contribute to epilepsy and consequently could be harnessed therapeutically are discussed in this Review.
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Affiliation(s)
- Dipan C Patel
- Fralin Biomedical Research Institute, Glial Biology in Health, Disease, and Cancer Center, Roanoke, VA, USA
| | - Bhanu P Tewari
- Fralin Biomedical Research Institute, Glial Biology in Health, Disease, and Cancer Center, Roanoke, VA, USA
| | - Lata Chaunsali
- Fralin Biomedical Research Institute, Glial Biology in Health, Disease, and Cancer Center, Roanoke, VA, USA
| | - Harald Sontheimer
- Fralin Biomedical Research Institute, Glial Biology in Health, Disease, and Cancer Center, Roanoke, VA, USA. .,School of Neuroscience, Virginia Tech, Blacksburg, VA, USA.
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Pajarillo E, Rizor A, Lee J, Aschner M, Lee E. The role of astrocytic glutamate transporters GLT-1 and GLAST in neurological disorders: Potential targets for neurotherapeutics. Neuropharmacology 2019; 161:107559. [PMID: 30851309 PMCID: PMC6731169 DOI: 10.1016/j.neuropharm.2019.03.002] [Citation(s) in RCA: 217] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/28/2019] [Accepted: 03/02/2019] [Indexed: 12/12/2022]
Abstract
Glutamate is the primary excitatory neurotransmitter in the central nervous system (CNS) which initiates rapid signal transmission in the synapse before its re-uptake into the surrounding glia, specifically astrocytes. The astrocytic glutamate transporters glutamate-aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) and their human homologs excitatory amino acid transporter 1 (EAAT1) and 2 (EAAT2), respectively, are the major transporters which take up synaptic glutamate to maintain optimal extracellular glutamic levels, thus preventing accumulation in the synaptic cleft and ensuing excitotoxicity. Growing evidence has shown that excitotoxicity is associated with various neurological disorders, including amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), manganism, ischemia, schizophrenia, epilepsy, and autism. While the mechanisms of neurological disorders are not well understood, the dysregulation of GLAST/GLT-1 may play a significant role in excitotoxicity and associated neuropathogenesis. The expression and function of GLAST/GLT-1 may be dysregulated at the genetic, epigenetic, transcriptional or translational levels, leading to high levels of extracellular glutamate and excitotoxicity. Consequently, understanding the regulatory mechanisms of GLAST/GLT-1 has been an area of interest in developing therapeutics for the treatment of neurological disorders. Pharmacological agents including β-lactam antibiotics, estrogen/selective estrogen receptor modulators (SERMs), growth factors, histone deacetylase inhibitors (HDACi), and translational activators have shown significant efficacy in enhancing the expression and function of GLAST/GLT-1 and glutamate uptake both in vitro and in vivo. This comprehensive review will discuss the regulatory mechanisms of GLAST/GLT-1, their association with neurological disorders, and the pharmacological agents which mediate their expression and function. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- Edward Pajarillo
- Department of Pharmaceutical Sciences, College of Pharmacy, Florida A&M University, Tallahassee, FL, 32301, USA
| | - Asha Rizor
- Department of Pharmaceutical Sciences, College of Pharmacy, Florida A&M University, Tallahassee, FL, 32301, USA
| | - Jayden Lee
- Department of Speech, Language & Hearing Sciences, Boston University, Boston, MA, 02215, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Eunsook Lee
- Department of Pharmaceutical Sciences, College of Pharmacy, Florida A&M University, Tallahassee, FL, 32301, USA.
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Ceftriaxone Treatment Affects EAAT2 Expression and Glutamatergic Neurotransmission and Exerts a Weak Anticonvulsant Effect in Young Rats. Int J Mol Sci 2019; 20:ijms20235852. [PMID: 31766528 PMCID: PMC6928884 DOI: 10.3390/ijms20235852] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/13/2019] [Accepted: 11/20/2019] [Indexed: 01/03/2023] Open
Abstract
Epilepsy is a common neurological disorder. Despite the availability of a wide range of antiepileptic drugs, these are unsuccessful in preventing seizures in 20–30% of patients. Therefore, new pharmacological strategies are urgently required to control seizures. Modulation of glutamate uptake may have potential in the treatment of pharmacoresistant forms of epilepsy. Previous research showed that the antibiotic ceftriaxone (CTX) increased the expression and functional activity of excitatory amino acid transporter 2 (EAAT2) and exerted considerable anticonvulsant effects. However, other studies did not confirm a significant anticonvulsant effect of CTX administration. We investigated the impacts of CTX treatment on EAAT expression and glutamatergic neurotransmission, as well its anticonvulsant action, in young male Wistar rats. As shown by a quantitative real-time polymerase chain reaction (qPCR) assay and a Western blot analysis, the mRNA but not the protein level of EAAT2 increased in the hippocampus following CTX treatment. Repetitive CTX administration had only a mild anticonvulsant effect on pentylenetetrazol (PTZ)-induced convulsions in a maximal electroshock threshold test (MEST). CTX treatment did not affect the glutamatergic neurotransmission, including synaptic efficacy, short-term facilitation, or the summation of excitatory postsynaptic potentials (EPSPs) in the hippocampus and temporal cortex. However, it decreased the field EPSP (fEPSP) amplitudes evoked by intense electrical stimulation. In conclusion, in young rats, CTX treatment did not induce overexpression of EAAT2, therefore exerting only a weak antiseizure effect. Our data provide new insight into the effects of modulation of EAAT2 expression on brain functioning.
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30
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Malik AR, Willnow TE. Excitatory Amino Acid Transporters in Physiology and Disorders of the Central Nervous System. Int J Mol Sci 2019; 20:ijms20225671. [PMID: 31726793 PMCID: PMC6888459 DOI: 10.3390/ijms20225671] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 12/12/2022] Open
Abstract
Excitatory amino acid transporters (EAATs) encompass a class of five transporters with distinct expression in neurons and glia of the central nervous system (CNS). EAATs are mainly recognized for their role in uptake of the amino acid glutamate, the major excitatory neurotransmitter. EAATs-mediated clearance of glutamate released by neurons is vital to maintain proper glutamatergic signalling and to prevent toxic accumulation of this amino acid in the extracellular space. In addition, some EAATs also act as chloride channels or mediate the uptake of cysteine, required to produce the reactive oxygen speciesscavenger glutathione. Given their central role in glutamate homeostasis in the brain, as well as their additional activities, it comes as no surprise that EAAT dysfunctions have been implicated in numerous acute or chronic diseases of the CNS, including ischemic stroke and epilepsy, cerebellar ataxias, amyotrophic lateral sclerosis, Alzheimer’s disease and Huntington’s disease. Here we review the studies in cellular and animal models, as well as in humans that highlight the roles of EAATs in the pathogenesis of these devastating disorders. We also discuss the mechanisms regulating EAATs expression and intracellular trafficking and new exciting possibilities to modulate EAATs and to provide neuroprotection in course of pathologies affecting the CNS.
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Affiliation(s)
- Anna R. Malik
- Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
- Correspondence:
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31
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Foster JB, Lashley R, Zhao F, Wang X, Kung N, Askwith CC, Lin L, Shultis MW, Hodgetts KJ, Lin CLG. Enhancement of tripartite synapses as a potential therapeutic strategy for Alzheimer's disease: a preclinical study in rTg4510 mice. Alzheimers Res Ther 2019; 11:75. [PMID: 31439023 PMCID: PMC6706914 DOI: 10.1186/s13195-019-0530-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 08/15/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND The lack of effective treatment options for Alzheimer's disease (AD) is of momentous societal concern. Synaptic loss is the hallmark of AD that correlates best with impaired memory and occurs early in the disease process, before the onset of clinical symptoms. We have developed a small-molecule, pyridazine-based series that enhances the structure and function of both the glial processes and the synaptic boutons that form the tripartite synapse. Previously, we have shown that these pyridazine derivatives exhibit profound efficacy in an amyloid precursor protein AD model. Here, we evaluated the efficacy of an advanced compound, LDN/OSU-0215111, in rTg4510 mice-an aggressive tauopathy model. METHODS rTg4510 mice were treated orally with vehicle or LDN/OSU-0215111 (10 mg/kg) daily from the early symptomatic stage (2 months old) to moderate (4 months old) and severe (8 months old) disease stages. At each time point, mice were subjected to a battery of behavioral tests to assess the activity levels and cognition. Also, tissue collections were performed on a subset of mice to analyze the tripartite synaptic changes, neurodegeneration, gliosis, and tau phosphorylation as assessed by immunohistochemistry and Western blotting. At 8 months of age, a subset of rTg4510 mice treated with compound was switched to vehicle treatment and analyzed behaviorally and biochemically 30 days after treatment cessation. RESULTS At both the moderate and severe disease stages, compound treatment normalized cognition and behavior as well as reduced synaptic loss, neurodegeneration, tau hyperphosporylation, and neuroinflammation. Importantly, after 30 days of treatment cessation, the benefits of compound treatment were sustained, indicating disease modification. We also found that compound treatment rapidly and robustly reduced tau hyperphosphorylation/deposition possibly via the inhibition of GSK3β. CONCLUSIONS The results show that LDN/OSU-0215111 provides benefits for multiple aspects of tauopathy-dependent pathology found in Alzheimer's disease including tripartite synapse normalization and reduction of toxic tau burden, which, in turn, likely accounted for normalized cognition and activity levels in compound-treated rTg4510 mice. This study, in combination with our previous work regarding the benefit of pyridazine derivatives against amyloid-dependent pathology, strongly supports pyridazine derivatives as a viable, clinically relevant, and disease-modifying treatment for many of the facets of Alzheimer's disease.
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Affiliation(s)
- Joshua B. Foster
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH USA
| | - Rashelle Lashley
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH USA
| | - Fangli Zhao
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH USA
| | - Xueqin Wang
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH USA
| | - Nydia Kung
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH USA
| | - Candice C. Askwith
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH USA
| | - Lin Lin
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA USA
| | - Michael W. Shultis
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA USA
| | - Kevin J. Hodgetts
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA USA
| | - Chien-Liang Glenn Lin
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH USA
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Chronic Unexpected Mild Stress Destroys Synaptic Plasticity of Neurons through a Glutamate Transporter, GLT-1, of Astrocytes in the Ischemic Stroke Rat. Neural Plast 2019; 2019:1615925. [PMID: 31019528 PMCID: PMC6452568 DOI: 10.1155/2019/1615925] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 01/27/2019] [Accepted: 02/21/2019] [Indexed: 02/03/2023] Open
Abstract
Background and Objective Chronic unexpected mild stress (CUMS) destroys synaptic plasticity of hippocampal regenerated neurons that may be involved in the occurrence of poststroke depression. Astrocytes uptake glutamate at the synapse and provide metabolic support for neighboring neurons. Currently, we aim to investigate whether CUMS inhibits synaptic formation of regenerated neurons through a glutamate transporter, GLT-1, of astrocytes in the ischemic stroke rats. Method We exposed the ischemic stroke rats to ceftriaxone, during the CUMS intervention period to determine the effects of GLT-1 on glutamate circulation by immunofluorescence and mass spectrometry and its influences to synaptic plasticity by western blot and transmission electron microscopy. Result CUMS evidently reduced the level of astroglial GLT-1 in the hippocampus of the ischemic rats (p < 0.05), resulting in smaller amount of glutamate being transported into astrocytes surrounding synapses (p < 0.05), and then expression of synaptophysin was suppressed (p < 0.05) in hippocampal dentate gyrus. The ultrastructures of synapses in dentate gyrus were adversely influenced including decreased proportion of smile synapses, shortened thickness of postsynaptic density, reduced number of vesicles, and widened average distance of the synaptic cleft (all p < 0.05). Moreover, ceftriaxone can promote glutamate circulation and synaptic plasticity (all p < 0.05) by raising astroglial GLT-1 (p < 0.05) and then improve depressive behaviors of the CUMS-induced model rats (p < 0.05). Conclusion Our study shows that CUMS destroys synaptic plasticity of regenerated neurons in the hippocampus through a glutamate transporter, GLT-1, of astrocytes in the ischemic stroke rats. This may indicate one potential pathogenesis of poststroke depression.
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Aucubin Alleviates Seizures Activity in Li-Pilocarpine-Induced Epileptic Mice: Involvement of Inhibition of Neuroinflammation and Regulation of Neurotransmission. Neurochem Res 2019; 44:472-484. [DOI: 10.1007/s11064-018-2700-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/05/2018] [Accepted: 12/11/2018] [Indexed: 12/21/2022]
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Alterations in mRNA expression of glutamate receptor subunits and excitatory amino acid transporters following pilocarpine-induced seizures in rats. Neurosci Lett 2018; 686:94-100. [DOI: 10.1016/j.neulet.2018.08.047] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/21/2018] [Accepted: 08/29/2018] [Indexed: 12/22/2022]
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35
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Yang Z, Wang J, Yu C, Xu P, Zhang J, Peng Y, Luo Z, Huang H, Zeng J, Xu Z. Inhibition of p38 MAPK Signaling Regulates the Expression of EAAT2 in the Brains of Epileptic Rats. Front Neurol 2018; 9:925. [PMID: 30429824 PMCID: PMC6220601 DOI: 10.3389/fneur.2018.00925] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 10/11/2018] [Indexed: 01/03/2023] Open
Abstract
Seizures induce the release of excitatory amino acids (EAAs) from the intracellular fluid to the extracellular fluid, and the released EAAs primarily comprise glutamic acid (Glu) and asparaginic acid (Asp). Glu neurotransmission functions via EAA transporters (EAATs) to maintain low concentrations of Glu in the extracellular space and avoid excitotoxicity. EAAT2, the most abundant Glu transporter subtype in the central nervous system (CNS), plays a key role in the regulation of glutamate transmission. Previous studies have shown that SB203580 promotes EAAT2 expression by inhibiting the p38 mitogen-activated protein kinase (MAPK) signaling pathway, but whether SB203580 upregulates EAAT2 expression in epileptic rats is unknown. This study demonstrated that EAAT2 expression was increased in the brain tissue of epileptic rats. Intraperitoneal injection of a specific inhibitor of p38 MAPK, SB203580, reduced the time to the first epileptic seizure and attenuated the seizure severity. In addition, SB203580 treatment increased the EAAT2 expression levels in the brain tissue of epileptic rats. These results suggest that SB203580 could regulate epileptic seizures via EAAT2.
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Affiliation(s)
- Zhang Yang
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,Department of Neurology, Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Jing Wang
- Department of Prevention and Health Care, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Changyin Yu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Ping Xu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Jun Zhang
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Yan Peng
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Zhong Luo
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Hao Huang
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Junwei Zeng
- Department of Physiology, Zunyi Medical University, Zunyi, China
| | - Zucai Xu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, China
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Zubareva OE, Kovalenko AA, Karyakin VB, Kalemenev SV, Lavrent’eva VV, Magazanik LG, Zaitsev AV. Changes in the Expression of Genes of the Glutamate Transporter and Subunits of the NMDA and AMPA Receptors in the Rat Amygdala in the Lithium–Pilocarpine Model of Epilepsy. NEUROCHEM J+ 2018. [DOI: 10.1134/s1819712418030170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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37
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Foster JB, Zhao F, Wang X, Xu Z, Lin K, Askwith CC, Hodgetts KJ, Lin CLG. Pyridazine-derivatives Enhance Structural and Functional Plasticity of Tripartite Synapse Via Activation of Local Translation in Astrocytic Processes. Neuroscience 2018; 388:224-238. [PMID: 30056115 DOI: 10.1016/j.neuroscience.2018.07.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/19/2018] [Accepted: 07/17/2018] [Indexed: 12/19/2022]
Abstract
Excitatory amino acid transporter 2 (EAAT2) is primarily located in perisynaptic astrocytic processes (PAP) where it plays a critical role in synaptic glutamate homeostasis. Dysregulation of EAAT2 at the translational level has been implicated in a myriad of neurological diseases. We previously discovered that pyridazine analogs can activate EAAT2 translation. Here, we sought to further refine the site and mechanism of compound action. We found that in vivo, compound treatment increased EAAT2 expression only in the PAP of astrocytes where EAAT2 mRNA also was identified. Direct application of compound to isolated PAP induced de novo EAAT2 protein synthesis, indicating that compound activates translation locally in the PAP. Using a screening process, we identified a set of PAP proteins that are rapidly up-regulated following compound treatment and a subset of these PAP proteins may be locally synthesized in the PAP. Importantly, these identified proteins are associated with the structural and functional capacity of the PAP, indicating compound enhanced plasticity of the PAP. Concomitantly, we found that pyridazine analogs increase synaptic protein expression in the synapse and enhance hippocampal long-term potentiation. This was not dependent upon compound-mediated local translation in neurons. This suggests that compound enhances the structural and functional capacity of the PAP which in turn facilitates enhanced plasticity of the tripartite synapse. Overall, this provides insight into the mechanism action site of pyridazine derivatives as well as the growing appreciation of the dynamic regulation and functional aspects of the PAP at the tripartite synapse.
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Affiliation(s)
- Joshua B Foster
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Fangli Zhao
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Xueqin Wang
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Zan Xu
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Kuanhung Lin
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Candice C Askwith
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Kevin J Hodgetts
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, United States
| | - Chien-Liang Glenn Lin
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States.
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38
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Vargas-Sánchez K, Mogilevskaya M, Rodríguez-Pérez J, Rubiano MG, Javela JJ, González-Reyes RE. Astroglial role in the pathophysiology of status epilepticus: an overview. Oncotarget 2018; 9:26954-26976. [PMID: 29928494 PMCID: PMC6003549 DOI: 10.18632/oncotarget.25485] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 05/09/2018] [Indexed: 12/11/2022] Open
Abstract
Status epilepticus is a medical emergency with elevated morbidity and mortality rates, and represents a leading cause of epilepsy-related deaths. Though status epilepticus can occur at any age, it manifests more likely in children and elderly people. Despite the common prevalence of epileptic disorders, a complete explanation for the mechanisms leading to development of self-limited or long lasting seizures (as in status epilepticus) are still lacking. Apart from neurons, research evidence suggests the involvement of immune and glial cells in epileptogenesis. Among glial cells, astrocytes represent an ideal target for the study of the pathophysiology of status epilepticus, due to their key role in homeostatic balance of the central nervous system. During status epilepticus, astroglial cells are activated by the presence of cytokines, damage associated molecular patterns and reactive oxygen species. The persistent activation of astrocytes leads to a decrease in glutamate clearance with a corresponding accumulation in the synaptic extracellular space, increasing the chance of neuronal excitotoxicity. Moreover, major alterations in astrocytic gap junction coupling, inflammation and receptor expression, facilitate the generation of seizures. Astrocytes are also involved in dysregulation of inhibitory transmission in the central nervous system and directly participate in ionic homeostatic alterations during status epilepticus. In the present review, we focus on the functional and structural changes in astrocytic activity that participate in the development and maintenance of status epilepticus, with special attention on concurrent inflammatory alterations. We also include potential astrocytic treatment targets for status epilepticus.
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Affiliation(s)
- Karina Vargas-Sánchez
- Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | | | - John Rodríguez-Pérez
- Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | - María G Rubiano
- Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | - José J Javela
- Grupo de Clínica y Salud Mental, Programa de Psicología, Universidad Católica de Pereira, Pereira, Colombia
| | - Rodrigo E González-Reyes
- Universidad del Rosario, Escuela de Medicina y Ciencias de la Salud, GI en Neurociencias-NeURos, Bogotá, Colombia
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Lim JA, Moon J, Kim TJ, Jun JS, Park B, Byun JI, Sunwoo JS, Park KI, Lee ST, Jung KH, Jung KY, Kim M, Jeon D, Chu K, Lee SK. Clustering of spontaneous recurrent seizures separated by long seizure-free periods: An extended video-EEG monitoring study of a pilocarpine mouse model. PLoS One 2018; 13:e0194552. [PMID: 29558523 PMCID: PMC5860752 DOI: 10.1371/journal.pone.0194552] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 03/06/2018] [Indexed: 02/07/2023] Open
Abstract
Seizure clustering is a common and significant phenomenon in patients with epilepsy. The clustering of spontaneous recurrent seizures (SRSs) in animal models of epilepsy, including mouse pilocarpine models, has been reported. However, most studies have analyzed seizures for a short duration after the induction of status epilepticus (SE). In this study, we investigated the detailed characteristics of seizure clustering in the chronic stage of a mouse pilocarpine-induced epilepsy model for an extended duration by continuous 24/7 video-EEG monitoring. A seizure cluster was defined as the occurrence of one or more seizures per day for at least three consecutive days and at least five seizures during the cluster period. We analyzed the cluster duration, seizure-free period, cluster interval, and numbers of seizures within and outside the seizure clusters. The video-EEG monitoring began 84.5±33.7 days after the induction of SE and continued for 53.7±20.4 days. Every mouse displayed seizure clusters, and 97.0% of the seizures occurred within a cluster period. The seizure clusters were followed by long seizure-free periods of 16.3±6.8 days, showing a cyclic pattern. The SRSs also occurred in a grouped pattern within a day. We demonstrate that almost all seizures occur in clusters with a cyclic pattern in the chronic stage of a mouse pilocarpine-induced epilepsy model. The seizure-free periods between clusters were long. These findings should be considered when performing in vivo studies using this animal model. Furthermore, this model might be appropriate for studying the unrevealed mechanism of ictogenesis.
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Affiliation(s)
- Jung-Ah Lim
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea.,Department of Neurology, Gangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, South Korea
| | - Jangsup Moon
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Tae-Joon Kim
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Jin-Sun Jun
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Byeongsu Park
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea.,Department of Neurology, Ulsan University Hospital, Ulsan University College of Medicine, Ulsan, Korea
| | - Jung-Ick Byun
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea.,Department of Neurology, Kyung Hee University Hospital at Gangdong, Seoul, South Korea
| | - Jun-Sang Sunwoo
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea.,Department of Neurology, Soonchunhyang University School of Medicine, Seoul, South Korea
| | - Kyung-Il Park
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea.,Department of Neurology, Seoul National University Hospital Healthcare System Gangnam Center, Seoul, South Korea
| | - Soon-Tae Lee
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Keun-Hwa Jung
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Ki-Young Jung
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Manho Kim
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Daejong Jeon
- Advanced Neural Technologies, Co., Seoul, South Korea
| | - Kon Chu
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Sang Kun Lee
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
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Astrocytic JWA deletion exacerbates dopaminergic neurodegeneration by decreasing glutamate transporters in mice. Cell Death Dis 2018; 9:352. [PMID: 29500411 PMCID: PMC5834463 DOI: 10.1038/s41419-018-0381-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 02/01/2018] [Accepted: 02/05/2018] [Indexed: 12/29/2022]
Abstract
Astrocytic JWA exerts neuroprotective roles by alleviating oxidative stress and inhibiting inflammation. However, the molecular mechanisms of how astrocytic JWA is involved in dopaminergic neurodegeneration in Parkinson's disease (PD) remain largely unknown. In this study, we found that astrocyte-specific JWA knockout mice (JWA CKO) exacerbated dopamine (DA) neuronal loss and motor dysfunction, and reduced the levels of DA and its metabolites in a 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine/probenecid (MPTP/p)-induced PD model. Astrocytic JWA deficiency repressed expression of excitatory amino-acid transporter 2 (GLT-1) and glutamate uptake both in vivo and in vitro. Further, the regulation of GLT-1 expression was involved in JWA-triggered activation of the MAPK and PI3K signaling pathways. JWA-increased GLT-1 expression was abolished by inhibitors of MEK and PI3K. Silencing CREB also abrogated JWA-increased GLT-1 expression and glutamate uptake. Additionally, JWA deficiency activated glial fibrillary acidic protein (GFAP), and increased the expression of STAT3. Similarly to the MPTP model, paraquat (PQ) exposure produced PD-like phenotypes in JWA CKO mice. Taken together, our findings provide novel insights into astrocytic JWA function in the pathogenesis of neurotoxin mouse models of PD.
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Folbergrová J, Ješina P, Kubová H, Otáhal J. Effect of Resveratrol on Oxidative Stress and Mitochondrial Dysfunction in Immature Brain during Epileptogenesis. Mol Neurobiol 2018; 55:7512-7522. [PMID: 29427088 DOI: 10.1007/s12035-018-0924-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 01/22/2018] [Indexed: 01/04/2023]
Abstract
The presence of oxidative stress in immature brain has been demonstrated during the acute phase of status epilepticus (SE). The knowledge regarding the long periods of survival after SE is not unequivocal, lacking direct evidence. To examine the presence and time profile of oxidative stress, its functional effect on mitochondria and the influence of an antioxidant treatment in immature rats during epileptogenesis, status epilepticus (SE) was induced in immature 12-day-old rats by Li-pilocarpine and at selected periods of the epileptogenesis; rat pups were subjected to examinations. Hydroethidine method was employed for detection of superoxide anion (O2.-), 3-nitrotyrosine (3-NT), and 4-hydroxynonenal (4-HNE) for oxidative damage of mitochondrial proteins and complex I activity for mitochondrial function. Natural polyphenolic antioxidant resveratrol was given in two schemes: "acute treatment," i.p. administration 30 min before, 30 and 60 min after induction of SE and "full treatment" when applications continued once daily for seven consecutive days (25 mg/kg each dose). The obtained results clearly document that the period of epileptogenesis studied (up to 4 weeks) in immature brain is associated with the significant enhanced production of O2.-, the increased levels of 3-NT and 4-HNE and the persisting deficiency of complex I activity. Application of resveratrol either completely prevented or significantly reduced markers both of oxidative stress and mitochondrial dysfunction. The findings suggest that targeting oxidative stress in combination with current antiepileptic therapies may provide a benefit in the treatment of epilepsy.
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Affiliation(s)
- Jaroslava Folbergrová
- Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic.
| | - Pavel Ješina
- Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Hana Kubová
- Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Jakub Otáhal
- Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic
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42
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Drugs to Alter Extracellular Concentration of Glutamate: Modulators of Glutamate Uptake Systems. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-1-4939-7228-9_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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43
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Lee ML, Martinez-Lozada Z, Krizman EN, Robinson MB. Brain endothelial cells induce astrocytic expression of the glutamate transporter GLT-1 by a Notch-dependent mechanism. J Neurochem 2017; 143:489-506. [PMID: 28771710 DOI: 10.1111/jnc.14135] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 07/07/2017] [Accepted: 07/13/2017] [Indexed: 01/13/2023]
Abstract
Neuron-secreted factors induce astrocytic expression of the glutamate transporter, GLT-1 (excitatory amino acid transporter 2). In addition to their elaborate anatomic relationships with neurons, astrocytes also have processes that extend to and envelop the vasculature. Although previous studies have demonstrated that brain endothelia contribute to astrocyte differentiation and maturation, the effects of brain endothelia on astrocytic expression of GLT-1 have not been examined. In this study, we tested the hypothesis that endothelia induce expression of GLT-1 by co-culturing astrocytes from mice that utilize non-coding elements of the GLT-1 gene to control expression of reporter proteins with the mouse endothelial cell line, bEND.3. We found that endothelia increased steady state levels of reporter and GLT-1 mRNA/protein. Co-culturing with primary rat brain endothelia also increases reporter protein, GLT-1 protein, and GLT-1-mediated glutamate uptake. The Janus kinase/signal transducer and activator of transcription 3, bone morphogenic protein/transforming growth factor β, and nitric oxide pathways have been implicated in endothelia-to-astrocyte signaling; we provide multiple lines of evidence that none of these pathways mediate the effects of endothelia on astrocytic GLT-1 expression. Using transwells with a semi-permeable membrane, we demonstrate that the effects of the bEND.3 cell line are dependent upon contact. Notch has also been implicated in endothelia-astrocyte signaling in vitro and in vivo. The first step of Notch signaling requires cleavage of Notch intracellular domain by γ-secretase. We demonstrate that the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester blocks endothelia-induced increases in GLT-1. We show that the levels of Notch intracellular domain are higher in nuclei of astrocytes co-cultured with endothelia, an effect also blocked by N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester. Finally, infection of co-cultures with shRNA directed against recombination signal binding protein for immunoglobulin kappa J, a Notch effector, also reduces endothelia-dependent increases in enhanced green fluorescent protein and GLT-1. Together, these studies support a novel role for Notch in endothelia-dependent induction of GLT-1 expression. Cover Image for this issue: doi. 10.1111/jnc.13825.
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Affiliation(s)
- Meredith L Lee
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Zila Martinez-Lozada
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Elizabeth N Krizman
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael B Robinson
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Systems Pharmacology and Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Lee ML, Martinez-Lozada Z, Krizman EN, Robinson MB. Brain endothelial cells induce astrocytic expression of the glutamate transporter GLT-1 by a Notch-dependent mechanism. J Neurochem 2017. [PMID: 28771710 DOI: 10.1111/jnc.13825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Neuron-secreted factors induce astrocytic expression of the glutamate transporter, GLT-1 (excitatory amino acid transporter 2). In addition to their elaborate anatomic relationships with neurons, astrocytes also have processes that extend to and envelop the vasculature. Although previous studies have demonstrated that brain endothelia contribute to astrocyte differentiation and maturation, the effects of brain endothelia on astrocytic expression of GLT-1 have not been examined. In this study, we tested the hypothesis that endothelia induce expression of GLT-1 by co-culturing astrocytes from mice that utilize non-coding elements of the GLT-1 gene to control expression of reporter proteins with the mouse endothelial cell line, bEND.3. We found that endothelia increased steady state levels of reporter and GLT-1 mRNA/protein. Co-culturing with primary rat brain endothelia also increases reporter protein, GLT-1 protein, and GLT-1-mediated glutamate uptake. The Janus kinase/signal transducer and activator of transcription 3, bone morphogenic protein/transforming growth factor β, and nitric oxide pathways have been implicated in endothelia-to-astrocyte signaling; we provide multiple lines of evidence that none of these pathways mediate the effects of endothelia on astrocytic GLT-1 expression. Using transwells with a semi-permeable membrane, we demonstrate that the effects of the bEND.3 cell line are dependent upon contact. Notch has also been implicated in endothelia-astrocyte signaling in vitro and in vivo. The first step of Notch signaling requires cleavage of Notch intracellular domain by γ-secretase. We demonstrate that the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester blocks endothelia-induced increases in GLT-1. We show that the levels of Notch intracellular domain are higher in nuclei of astrocytes co-cultured with endothelia, an effect also blocked by N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester. Finally, infection of co-cultures with shRNA directed against recombination signal binding protein for immunoglobulin kappa J, a Notch effector, also reduces endothelia-dependent increases in enhanced green fluorescent protein and GLT-1. Together, these studies support a novel role for Notch in endothelia-dependent induction of GLT-1 expression. Cover Image for this issue: doi. 10.1111/jnc.13825.
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Affiliation(s)
- Meredith L Lee
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Zila Martinez-Lozada
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Elizabeth N Krizman
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael B Robinson
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Systems Pharmacology and Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Liu B, Teschemacher AG, Kasparov S. Astroglia as a cellular target for neuroprotection and treatment of neuro-psychiatric disorders. Glia 2017; 65:1205-1226. [PMID: 28300322 PMCID: PMC5669250 DOI: 10.1002/glia.23136] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 12/12/2022]
Abstract
Astrocytes are key homeostatic cells of the central nervous system. They cooperate with neurons at several levels, including ion and water homeostasis, chemical signal transmission, blood flow regulation, immune and oxidative stress defense, supply of metabolites and neurogenesis. Astroglia is also important for viability and maturation of stem-cell derived neurons. Neurons critically depend on intrinsic protective and supportive properties of astrocytes. Conversely, all forms of pathogenic stimuli which disturb astrocytic functions compromise neuronal functionality and viability. Support of neuroprotective functions of astrocytes is thus an important strategy for enhancing neuronal survival and improving outcomes in disease states. In this review, we first briefly examine how astrocytic dysfunction contributes to major neurological disorders, which are traditionally associated with malfunctioning of processes residing in neurons. Possible molecular entities within astrocytes that could underpin the cause, initiation and/or progression of various disorders are outlined. In the second section, we explore opportunities enhancing neuroprotective function of astroglia. We consider targeting astrocyte-specific molecular pathways which are involved in neuroprotection or could be expected to have a therapeutic value. Examples of those are oxidative stress defense mechanisms, glutamate uptake, purinergic signaling, water and ion homeostasis, connexin gap junctions, neurotrophic factors and the Nrf2-ARE pathway. We propose that enhancing the neuroprotective capacity of astrocytes is a viable strategy for improving brain resilience and developing new therapeutic approaches.
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Affiliation(s)
- Beihui Liu
- School of Physiology, Pharmacology and NeuroscienceUniversity of Bristol, University WalkBS8 1TDUnited Kingdom
| | - Anja G. Teschemacher
- School of Physiology, Pharmacology and NeuroscienceUniversity of Bristol, University WalkBS8 1TDUnited Kingdom
| | - Sergey Kasparov
- School of Physiology, Pharmacology and NeuroscienceUniversity of Bristol, University WalkBS8 1TDUnited Kingdom
- Institute for Chemistry and BiologyBaltic Federal UniversityKaliningradRussian Federation
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Filippidis AS, Carozza RB, Rekate HL. Aquaporins in Brain Edema and Neuropathological Conditions. Int J Mol Sci 2016; 18:ijms18010055. [PMID: 28036023 PMCID: PMC5297690 DOI: 10.3390/ijms18010055] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 12/20/2016] [Accepted: 12/20/2016] [Indexed: 01/22/2023] Open
Abstract
The aquaporin (AQP) family of water channels are a group of small, membrane-spanning proteins that are vital for the rapid transport of water across the plasma membrane. These proteins are widely expressed, from tissues such as the renal epithelium and erythrocytes to the various cells of the central nervous system. This review will elucidate the basic structure and distribution of aquaporins and discuss the role of aquaporins in various neuropathologies. AQP1 and AQP4, the two primary aquaporin molecules of the central nervous system, regulate brain water and CSF movement and contribute to cytotoxic and vasogenic edema, where they control the size of the intracellular and extracellular fluid volumes, respectively. AQP4 expression is vital to the cellular migration and angiogenesis at the heart of tumor growth; AQP4 is central to dysfunctions in glutamate metabolism, synaptogenesis, and memory consolidation; and AQP1 and AQP4 adaptations have been seen in obstructive and non-obstructive hydrocephalus and may be therapeutic targets.
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Affiliation(s)
- Aristotelis S Filippidis
- Division of Neurosurgery, Beth Israel Deaconess Medical School, Harvard Medical School, Boston, MA 02115, USA.
- Department of Neurosurgery, Boston Medical Center, Boston University, Boston, MA 02215, USA.
| | | | - Harold L Rekate
- Department of Neurosurgery, The Chiari Institute, Hofstra Northwell School of Medicine, Hempstead, NY 11549, USA.
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Sha L, Wang X, Li J, Shi X, Wu L, Shen Y, Xu Q. Pharmacologic inhibition of Hsp90 to prevent GLT-1 degradation as an effective therapy for epilepsy. J Exp Med 2016; 214:547-563. [PMID: 28028152 PMCID: PMC5294855 DOI: 10.1084/jem.20160667] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 10/11/2016] [Accepted: 12/13/2016] [Indexed: 12/12/2022] Open
Abstract
Sha et al. report that Hsp90β, which is up-regulated in astrocytes of human epileptogenic tissue, interacts with GLT-1 and recruits it to 20S proteasome for degradation. The Hsp90 inhibitor 17AAG exhibits beneficial effects in a model of temporal lobe epilepsy. The glutamate transporter GLT-1 is critical for the maintenance of low interstitial glutamate concentrations. Loss of GLT-1 is commonly observed in neurological disorders, including temporal lobe epilepsy (TLE). Despite the hypothesis that targeting the mechanisms of GLT-1 deficiency may be a novel strategy for treating drug-resistant epilepsy, the underlying molecular cascade remains largely unknown. Here, we show that Hsp90β is up-regulated in reactive astrocytes of the epileptic hippocampus in patients with TLE and mouse models of epilepsy. Inhibition of Hsp90, but not Hsp70, increased GLT-1 levels. Mechanistically, Hsp90β recruits GLT-1 to the 20S proteasome, thereby promoting GLT-1 degradation. Hsp90 inhibitor prevents GLT-1 degradation by disrupting the association between Hsp90β and GLT-1. Using a model of TLE, we demonstrated that long-term systemic administration of 17AAG dramatically suppressed spontaneous recurrent seizures and ameliorated astrogliosis. Overall, these results suggest that up-regulation of GLT-1 by inhibiting Hsp90β in reactive astrocytes may be a potential therapeutic target for the treatment of epilepsy and excitotoxicity.
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Affiliation(s)
- Longze Sha
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Xueqin Wang
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Jing Li
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Xinze Shi
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Liwen Wu
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Yan Shen
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Qi Xu
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
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Mechanisms of Excessive Extracellular Glutamate Accumulation in Temporal Lobe Epilepsy. Neurochem Res 2016; 42:1724-1734. [DOI: 10.1007/s11064-016-2105-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 12/17/2022]
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Mohammadi M, Zare Z, Allah-Moradi E, Vaezi N, Valadan R, Tehrani M. Alterations in mRNA and protein expression of glutamate transporters in rat hippocampus after paraoxon exposure. Neurotoxicology 2016; 57:251-257. [PMID: 27769869 DOI: 10.1016/j.neuro.2016.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/15/2016] [Accepted: 10/15/2016] [Indexed: 01/30/2023]
Abstract
Organophosphates affect brain function through a variety of mechanisms beyond their shared role as cholinesterase inhibitors. The aim of the current study was to investigate the changes in the expression of glial (GLAST and GLT-1) and neuronal (EAAC1) glutamate transporters at mRNA and protein levels in paraoxon-treated rat hippocampus. Adult male Wistar rats were intraperitoneally treated with either vehicle (corn oil) or one of three dosages of paraoxon (0.3, 0.7 or 1mg/kg). After 4 or 18h, both hippocampi of each rat were collected to detect mRNA and protein expression of glutamate transporters using the quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and western blotting, respectively. Animals treated with 0.3mg/kg paraoxon showed no difference in mRNA and protein levels of the glutamate transporters when compared with control group. At 4h after exposure with 0.7 and 1mg/kg paraoxon, the expression of GLAST and GLT-1 increased at mRNA and protein levels and remained elevated after 18h. No difference in the expression of EAAC1 at mRNA and protein levels was observed in any paraoxon-treated groups compared with the control group. This study showed an increased expression of glial (GLAST and GLT-1), but not neuronal (EAAC1) glutamate transporters, in adult rat hippocampus following administration of convulsive dosages of paraoxon. These suggest a protective and compensatory adaptation for effective uptake of glutamate in hippocampus induced by paraoxon and thus attenuating seizure activity.
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Affiliation(s)
- Moslem Mohammadi
- Department of Physiology & Pharmacology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Zohreh Zare
- Department of Anatomical Sciences, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Esmaeil Allah-Moradi
- Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Narges Vaezi
- Department of Toxicology and Pharmacology, School of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Reza Valadan
- Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Molecular and Cell Biology Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mohsen Tehrani
- Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Molecular and Cell Biology Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
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Hubbard JA, Szu JI, Yonan JM, Binder DK. Regulation of astrocyte glutamate transporter-1 (GLT1) and aquaporin-4 (AQP4) expression in a model of epilepsy. Exp Neurol 2016; 283:85-96. [PMID: 27155358 DOI: 10.1016/j.expneurol.2016.05.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 04/23/2016] [Accepted: 05/01/2016] [Indexed: 12/31/2022]
Abstract
Astrocytes regulate extracellular glutamate and water homeostasis through the astrocyte-specific membrane proteins glutamate transporter-1 (GLT1) and aquaporin-4 (AQP4), respectively. The role of astrocytes and the regulation of GLT1 and AQP4 in epilepsy are not fully understood. In this study, we investigated the expression of GLT1 and AQP4 in the intrahippocampal kainic acid (IHKA) model of temporal lobe epilepsy (TLE). We used real-time polymerase chain reaction (RT-PCR), Western blot, and immunohistochemical analysis at 1, 4, 7, and 30days after kainic acid-induced status epilepticus (SE) to determine hippocampal glial fibrillary acidic protein (GFAP, a marker for reactive astrocytes), GLT1, and AQP4 expression changes during the development of epilepsy (epileptogenesis). Following IHKA, all mice had SE and progressive increases in GFAP immunoreactivity and GFAP protein expression out to 30days post-SE. A significant initial increase in dorsal hippocampal GLT1 immunoreactivity and protein levels were observed 1day post SE and followed by a marked downregulation at 4 and 7days post SE with a return to near control levels by 30days post SE. AQP4 dorsal hippocampal protein expression was significantly downregulated at 1day post SE and was followed by a gradual return to baseline levels with a significant increase in ipsilateral protein levels by 30days post SE. Transient increases in GFAP and AQP4 mRNA were also observed. Our findings suggest that specific molecular changes in astrocyte glutamate transporters and water channels occur during epileptogenesis in this model, and suggest the novel therapeutic strategy of restoring glutamate and water homeostasis.
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Affiliation(s)
- Jacqueline A Hubbard
- Department of Biochemistry and Molecular Biology, University of California, Riverside, USA
| | - Jenny I Szu
- Neuroscience Graduate Program, University of California, Riverside, USA
| | - Jennifer M Yonan
- Neuroscience Graduate Program, University of California, Riverside, USA
| | - Devin K Binder
- Neuroscience Graduate Program, University of California, Riverside, USA; Center for Glial-Neuronal Interactions, University of California, Riverside, USA; Division of Biomedical Sciences, School of Medicine, University of California, Riverside.
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