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Çarçak N, Onat F, Sitnikova E. Astrocytes as a target for therapeutic strategies in epilepsy: current insights. Front Mol Neurosci 2023; 16:1183775. [PMID: 37583518 PMCID: PMC10423940 DOI: 10.3389/fnmol.2023.1183775] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/12/2023] [Indexed: 08/17/2023] Open
Abstract
Astrocytes are specialized non-neuronal glial cells of the central nervous system, contributing to neuronal excitability and synaptic transmission (gliotransmission). Astrocytes play a key roles in epileptogenesis and seizure generation. Epilepsy, as a chronic disorder characterized by neuronal hyperexcitation and hypersynchronization, is accompanied by substantial disturbances of glial cells and impairment of astrocytic functions and neuronal signaling. Anti-seizure drugs that provide symptomatic control of seizures primarily target neural activity. In epileptic patients with inadequate control of seizures with available anti-seizure drugs, novel therapeutic candidates are needed. These candidates should treat epilepsy with anti-epileptogenic and disease-modifying effects. Evidence from human and animal studies shows that astrocytes have value for developing new anti-seizure and anti-epileptogenic drugs. In this review, we present the key functions of astrocytes contributing to neuronal hyperexcitability and synaptic activity following an etiology-based approach. We analyze the role of astrocytes in both development (epileptogenesis) and generation of seizures (ictogenesis). Several promising new strategies that attempted to modify astroglial functions for treating epilepsy are being developed: (1) selective targeting of glia-related molecular mechanisms of glutamate transport; (2) modulation of tonic GABA release from astrocytes; (3) gliotransmission; (4) targeting the astrocytic Kir4.1-BDNF system; (5) astrocytic Na+/K+/ATPase activity; (6) targeting DNA hypo- or hypermethylation of candidate genes in astrocytes; (7) targeting astrocytic gap junction regulators; (8) targeting astrocytic adenosine kinase (the major adenosine-metabolizing enzyme); and (9) targeting microglia-astrocyte communication and inflammatory pathways. Novel disease-modifying therapeutic strategies have now been developed, such as astroglia-targeted gene therapy with a broad spectrum of genetic constructs to target astroglial cells.
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Affiliation(s)
- Nihan Çarçak
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
- Institute of Health Sciences, Department of Neuroscience, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Filiz Onat
- Institute of Health Sciences, Department of Neuroscience, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
- Department of Medical Pharmacology, Faculty of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Evgenia Sitnikova
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Moscow, Russia
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2
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Citraro R, Bosco F, Di Gennaro G, Tallarico M, Guarnieri L, Gallelli L, Rania V, Siniscalchi A, De Sarro G, Leo A. An In Vivo Electroencephalographic Analysis of the Effect of Riluzole against Limbic and Absence Seizure and Comparison with Glutamate Antagonists. Pharmaceutics 2023; 15:2006. [PMID: 37514193 PMCID: PMC10386681 DOI: 10.3390/pharmaceutics15072006] [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: 03/08/2023] [Revised: 04/20/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Riluzole (RLZ) has demonstrated neuroprotective effects in several neurological disorders. These neuroprotective effects seem to be mainly due to its ability to inhibit the excitatory glutamatergic neurotransmission, acting on different targets located both at the presynaptic and postsynaptic levels. METHODS In the present study, we evaluated the effects of Riluzole (RLZ) against limbic seizures, induced by AMPA, kainate, and NMDA receptor agonists in Sprague-Dawley rats, and in a well-validated genetic model of absence epilepsy, the WAG/Rij rat. Furthermore, in this latter model, we also studied the effect of RLZ in co-administration with the competitive NMDA receptor antagonist, CPP, or the non-competitive AMPA receptor antagonist, THIQ-10c, on spike-wave discharges (SWDs) in WAG/Rij rats, to understand the potential involvement of AMPA and NMDA receptors in the anti-absence effect of RLZ. RESULTS In Sprague-Dawley rats, RLZ pretreatment significantly reduced the limbic seizure severity induced by glutamatergic agonists, suggesting an antagonism of RLZ mainly on NMDA rather than non-NMDA receptors. RLZ also reduced SWD parameters in WAG/Rij rats. Interestingly, the co-administration of RLZ with CPP did not increase the anti-absence activity of RLZ in this model, advocating a competitive effect on the NMDA receptor. In contrast, the co-administration of RLZ with THIQ-10c induced an additive effect against absence seizure in WAG/Rij rats. CONCLUSIONS these results suggest that the antiepileptic effects of RLZ, in both seizure models, can be mainly due to the antagonism of the NMDA glutamatergic receptors.
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Affiliation(s)
- Rita Citraro
- Section of Pharmacology, Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
| | - Francesca Bosco
- Section of Pharmacology, Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
| | - Gianfranco Di Gennaro
- Section of Pharmacology, Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
| | - Martina Tallarico
- Section of Pharmacology, Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
| | - Lorenza Guarnieri
- Section of Pharmacology, Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
| | - Luca Gallelli
- Section of Pharmacology, Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
| | - Vincenzo Rania
- Section of Pharmacology, Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
| | - Antonio Siniscalchi
- Department of Neurology and Stroke Unit, Annunziata Hospital of Cosenza, 87100 Cosenza, Italy
| | - Giovambattista De Sarro
- Section of Pharmacology, Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
| | - Antonio Leo
- Section of Pharmacology, Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy
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3
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Potier B, Lallemant L, Parrot S, Huguet-Lachon A, Gourdon G, Dutar P, Gomes-Pereira M. DM1 Transgenic Mice Exhibit Abnormal Neurotransmitter Homeostasis and Synaptic Plasticity in Association with RNA Foci and Mis-Splicing in the Hippocampus. Int J Mol Sci 2022; 23:ijms23020592. [PMID: 35054778 PMCID: PMC8775431 DOI: 10.3390/ijms23020592] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 12/31/2021] [Accepted: 01/02/2022] [Indexed: 02/01/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a severe neuromuscular disease mediated by a toxic gain of function of mutant RNAs. The neuropsychological manifestations affect multiple domains of cognition and behavior, but their etiology remains elusive. Transgenic DMSXL mice carry the DM1 mutation, show behavioral abnormalities, and express low levels of GLT1, a critical regulator of glutamate concentration in the synaptic cleft. However, the impact of glutamate homeostasis on neurotransmission in DM1 remains unknown. We confirmed reduced glutamate uptake in the DMSXL hippocampus. Patch clamp recordings in hippocampal slices revealed increased amplitude of tonic glutamate currents in DMSXL CA1 pyramidal neurons and DG granule cells, likely mediated by higher levels of ambient glutamate. Unexpectedly, extracellular GABA levels and tonic current were also elevated in DMSXL mice. Finally, we found evidence of synaptic dysfunction in DMSXL mice, suggestive of abnormal short-term plasticity, illustrated by an altered LTP time course in DG and in CA1. Synaptic dysfunction was accompanied by RNA foci accumulation in localized areas of the hippocampus and by the mis-splicing of candidate genes with relevant functions in neurotransmission. Molecular and functional changes triggered by toxic RNA may induce synaptic abnormalities in restricted brain areas that favor neuronal dysfunction.
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Affiliation(s)
- Brigitte Potier
- LuMIn, CNRS FRE2036, ENS Paris-Saclay, CentraleSupelec, Université Paris-Saclay, 91190 Gif-sur-Yvette, France; (B.P.); (P.D.)
| | - Louison Lallemant
- Centre de Recherche en Myologie, Institut de Myologie, Inserm, Sorbonne Université, 75013 Paris, France; (L.L.); (A.H.-L.)
| | - Sandrine Parrot
- Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR5292, Université Lyon 1, 69500 Bron, France;
| | - Aline Huguet-Lachon
- Centre de Recherche en Myologie, Institut de Myologie, Inserm, Sorbonne Université, 75013 Paris, France; (L.L.); (A.H.-L.)
| | - Geneviève Gourdon
- Centre de Recherche en Myologie, Institut de Myologie, Inserm, Sorbonne Université, 75013 Paris, France; (L.L.); (A.H.-L.)
- Correspondence: (G.G.); (M.G.-P.)
| | - Patrick Dutar
- LuMIn, CNRS FRE2036, ENS Paris-Saclay, CentraleSupelec, Université Paris-Saclay, 91190 Gif-sur-Yvette, France; (B.P.); (P.D.)
| | - Mário Gomes-Pereira
- Centre de Recherche en Myologie, Institut de Myologie, Inserm, Sorbonne Université, 75013 Paris, France; (L.L.); (A.H.-L.)
- Correspondence: (G.G.); (M.G.-P.)
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4
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Parrot S, Corscadden A, Lallemant L, Benyamine H, Comte JC, Huguet-Lachon A, Gourdon G, Gomes-Pereira M. Defects in Mouse Cortical Glutamate Uptake Can Be Unveiled In Vivo by a Two-in-One Quantitative Microdialysis. ACS Chem Neurosci 2022; 13:134-142. [PMID: 34923816 DOI: 10.1021/acschemneuro.1c00634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Extracellular glutamate levels are maintained low by efficient transporters, whose dysfunction can cause neuronal hyperexcitability, excitotoxicity, and neurological disease. While many methods estimate glutamate uptake in vitro/ex vivo, a limited number of techniques address glutamate transport in vivo. Here, we used in vivo microdialysis in a two-in-one approach combining reverse dialysis of isotopic glutamate to measure uptake ability and zero-flow (ZF) methods to quantify extracellular glutamate levels. The complementarity of both techniques is discussed on methodological and anatomical basis. We used a transgenic mouse model of human disease, expressing low levels of the EAAT-2/GLT1 glutamate transporter, to validate our approach in a relevant animal model. As expected, isotopic analysis revealed an overall decrease in glutamate uptake, while the ZF method unveiled higher extracellular glutamate levels in these mice. We propose a sensitive and expedite two-in-one microdialysis approach that is sufficiently robust to reveal significant differences in neurotransmitter uptake and extracellular levels through the analysis of a relatively low number of animals.
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Affiliation(s)
- Sandrine Parrot
- Inserm U1028, CNRS UMR5292, Université de Lyon, Lyon Neuroscience Research Center, Bron F-69500, France
| | - Alex Corscadden
- Inserm U1028, CNRS UMR5292, Université de Lyon, Lyon Neuroscience Research Center, Bron F-69500, France
| | - Louison Lallemant
- Sorbonne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, Paris 75013, France
| | - Hélène Benyamine
- Sorbonne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, Paris 75013, France
| | - Jean-Christophe Comte
- Inserm U1028, CNRS UMR5292, Université de Lyon, Lyon Neuroscience Research Center, Bron F-69500, France
| | - Aline Huguet-Lachon
- Sorbonne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, Paris 75013, France
| | - Geneviève Gourdon
- Sorbonne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, Paris 75013, France
| | - Mário Gomes-Pereira
- Sorbonne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, Paris 75013, France
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5
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Craeghs L, Callaerts-Vegh Z, Verslegers M, Van der Jeugd A, Govaerts K, Dresselaers T, Wogensen E, Verreet T, Moons L, Benotmane MA, Himmelreich U, D'Hooge R. Prenatal Radiation Exposure Leads to Higher-Order Telencephalic Dysfunctions in Adult Mice That Coincide with Reduced Synaptic Plasticity and Cerebral Hypersynchrony. Cereb Cortex 2021; 32:3525-3541. [PMID: 34902856 DOI: 10.1093/cercor/bhab431] [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: 04/06/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 11/14/2022] Open
Abstract
Higher-order telencephalic circuitry has been suggested to be especially vulnerable to irradiation or other developmentally toxic impact. This report details the adult effects of prenatal irradiation at a sensitive time point on clinically relevant brain functions controlled by telencephalic regions, hippocampus (HPC), and prefrontal cortex (PFC). Pregnant C57Bl6/J mice were whole-body irradiated at embryonic day 11 (start of neurogenesis) with X-ray intensities of 0.0, 0.5, or 1.0 Gy. Female offspring completed a broad test battery of HPC-/PFC-controlled tasks that included cognitive performance, fear extinction, exploratory, and depression-like behaviors. We examined neural functions that are mechanistically related to these behavioral and cognitive changes, such as hippocampal field potentials and long-term potentiation, functional brain connectivity (by resting-state functional magnetic resonance imaging), and expression of HPC vesicular neurotransmitter transporters (by immunohistochemical quantification). Prenatally exposed mice displayed several higher-order dysfunctions, such as decreased nychthemeral activity, working memory defects, delayed extinction of threat-evoked response suppression as well as indications of perseverative behavior. Electrophysiological examination indicated impaired hippocampal synaptic plasticity. Prenatal irradiation also induced cerebral hypersynchrony and increased the number of glutamatergic HPC terminals. These changes in brain connectivity and plasticity could mechanistically underlie the irradiation-induced defects in higher telencephalic functions.
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Affiliation(s)
- Livine Craeghs
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Zsuzsanna Callaerts-Vegh
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Mieke Verslegers
- Department of Radiobiology, Institute for Environmental Health and Safety, Nuclear Research Center (SCK CEN), Mol 2400, Belgium
| | - Ann Van der Jeugd
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Kristof Govaerts
- Department of Imaging & Pathology, Research Group Biomedical MRI, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Tom Dresselaers
- Department of Imaging & Pathology, Research Group Biomedical MRI, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Elise Wogensen
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Tine Verreet
- Department of Radiobiology, Institute for Environmental Health and Safety, Nuclear Research Center (SCK CEN), Mol 2400, Belgium
| | - Lieve Moons
- Department of Biology, Research Group Neural Circuit Development and Regeneration, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Mohammed A Benotmane
- Department of Radiobiology, Institute for Environmental Health and Safety, Nuclear Research Center (SCK CEN), Mol 2400, Belgium
| | - Uwe Himmelreich
- Department of Imaging & Pathology, Research Group Biomedical MRI, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Rudi D'Hooge
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
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6
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Korkmaz OT, Arkan S, Öncü-Kaya EM, Ateş N, Tunçel N. Vasoactive intestinal peptide (VIP) conducts the neuronal activity during absence seizures: GABA seems to be the main mediator of VIP. Neurosci Lett 2021; 765:136268. [PMID: 34571088 DOI: 10.1016/j.neulet.2021.136268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 11/27/2022]
Abstract
Absence epilepsy is classified as a childhood generalized epilepsy syndrome with distinctive electroencephalographic patterns. The Wistar Albino Glaxo originating from Rijswijk (WAG/Rij) strain is a very well validated animal model of absence epilepsy that also shows behavioral deficits. In addition to the gastrointestinal system, VIP is highly expressed throughout numerous brain regions, and it plays crucial roles as a neurotransmitter and as a neuromodulatory, neurotrophic and neuroprotective factor in both the central and peripheral nervous systems. In this study, adult WAG/Rij rats were divided into two groups (n = 10): a group that was administered VIP (25 ng/kg i.p.) every 2 days for 15 days and an age-matched control group that was administered physiological saline. Electrical brain activity and behavior (depressive- like behavior, learning and memory and anxiety) were investigated in both groups. In addition, the extracellular concentrations of GABA and glutamate and the GABA/glutamate ratio were measured by high-performance liquid chromatography in microdialysate samples collected from the somatosensorial cortex of WAG/Rij rats. Our results demonstrated that VIP treatment significantly suppressed the total duration and number of spike wave discharges in WAG/Rij rats. However, VIP had no significant effect on behavior. VIP increased the extracellular concentration of GABA and the GABA/glutamate ratio in the somatosensory cortex. In conclusion, VIP has suppressive effects on absence seizures, possibly by increasing the GABA concentration and inducing the transformation of glutamate to GABA in the somatosensory cortex of WAG/Rij rats.
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Affiliation(s)
- Orhan Tansel Korkmaz
- Department of Physiology, Faculty of Medicine, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey.
| | - Sertan Arkan
- Department of Physiology, Medical Faculty, Kocaeli University, 41380, Kocaeli, Turkey
| | - Elif Mine Öncü-Kaya
- Department of Chemistry, Science Faculty, Eskisehir Technical University, 26470 Eskisehir, Turkey
| | - Nurbay Ateş
- Department of Physiology, Medical Faculty, Kocaeli University, 41380, Kocaeli, Turkey
| | - Neşe Tunçel
- Department of Physiology, Faculty of Medicine, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey
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7
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Gruenbaum BF, Sandhu MRS, Bertasi RAO, Bertasi TGO, Schonwald A, Kurup A, Gruenbaum SE, Freedman IG, Funaro MC, Blumenfeld H, Sanacora G. Absence seizures and their relationship to depression and anxiety: Evidence for bidirectionality. Epilepsia 2021; 62:1041-1056. [PMID: 33751566 PMCID: PMC8443164 DOI: 10.1111/epi.16862] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 12/12/2022]
Abstract
Absence seizures (AS), presenting as short losses of consciousness with staring spells, are a common manifestation of childhood epilepsy that is associated with behavioral, emotional, and social impairments. It has also been suggested that patients with AS are more likely to suffer from mood disorders such as depression and anxiety. This systematic review and meta-analysis synthesizes human and animal models that investigated mood disorders and AS. Of the 1019 scientific publications identified, 35 articles met the inclusion criteria for this review. We found that patients with AS had greater odds of developing depression and anxiety when compared to controls (odds ratio = 4.93, 95% confidence interval = 2.91-8.35, p < .01). The included studies further suggest a strong correlation between AS and depression and anxiety in the form of a bidirectional relationship. The current literature emphasizes that these conditions likely share underlying mechanisms, such as genetic predisposition, neurophysiology, and anatomical pathways. Further research will clarify this relationship and ensure more effective treatment for AS and mood disorders.
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Affiliation(s)
- Benjamin F Gruenbaum
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Jacksonville, Florida, USA
| | - Mani Ratnesh S Sandhu
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Raphael A O Bertasi
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Jacksonville, Florida, USA
| | - Tais G O Bertasi
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Jacksonville, Florida, USA
| | - Antonia Schonwald
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Anirudh Kurup
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Shaun E Gruenbaum
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Jacksonville, Florida, USA
| | - Isaac G Freedman
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Melissa C Funaro
- Harvey Cushing/John Hay Whitney Medical Library, Yale University, New Haven, Connecticut, USA
| | - Hal Blumenfeld
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Neuroscience, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Neurosurgery, Yale School of Medicine, New Haven, Connecticut, USA
| | - Gerard Sanacora
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
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8
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Saha P, Gupta R, Sen T, Sen N. Histone Deacetylase 4 Downregulation Elicits Post-Traumatic Psychiatric Disorders through Impairment of Neurogenesis. J Neurotrauma 2019; 36:3284-3296. [PMID: 31169064 DOI: 10.1089/neu.2019.6373] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
An enduring deficit in neurogenesis largely contributes to the development of severe post-traumatic psychiatric disorders such as anxiety, depression, and memory impairment following traumatic brain injury (TBI); however, the mechanism remains obscure. Here we have shown that an imbalance in the generation of γ-aminobutyric acid (GABA)ergic and glutamatergic neurons due to aberrant induction of vesicular glutamate transporter 1 (vGlut1)-positive glutamatergic cells is responsible for impaired neuronal differentiation in the hippocampus following TBI. To elucidate the molecular mechanism, we found that TBI activates a transcription factor, Pax3, by increasing its acetylation status, and subsequently induces Ngn2 transcription. This event, in turn, augments the vGlut1-expressing glutamatergic neurons and accumulation of excess glutamate in the hippocampus that can affect neuronal differentiation. In our study the acetylation of Pax3 was increased due to loss of its interaction with a deacetylase, histone deacetylase 4 (HDAC4), which was downregulated after TBI. TBI-induced activation of GSK3β was responsible for the degradation of HDAC4. We also showed that overexpression of HDAC4 before TBI reduces Pax3 acetylation by restoring an interaction between HDAC4 and Pax3 in the hippocampus. This event prevents the aberrant induction of vGlut1-positive glutamatergic neurons by decreasing the Ngn2 level and subsequently reinforces the balance between GABAergic and glutamatergic neurons following TBI. Further, we found that overexpression of HDAC4 in the hippocampus improves anxiety, depressive-like behavior, and memory functions following TBI.
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Affiliation(s)
- Pampa Saha
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rajaneesh Gupta
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Tanusree Sen
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Nilkantha Sen
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
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9
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Pathophysiology of absence epilepsy: Insights from genetic models. Neurosci Lett 2018; 667:53-65. [DOI: 10.1016/j.neulet.2017.02.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/08/2017] [Accepted: 02/12/2017] [Indexed: 11/21/2022]
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10
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Steinkellner T, Zell V, Farino ZJ, Sonders MS, Villeneuve M, Freyberg RJ, Przedborski S, Lu W, Freyberg Z, Hnasko TS. Role for VGLUT2 in selective vulnerability of midbrain dopamine neurons. J Clin Invest 2018; 128:774-788. [PMID: 29337309 DOI: 10.1172/jci95795] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/21/2017] [Indexed: 12/22/2022] Open
Abstract
Parkinson's disease is characterized by the loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). DA neurons in the ventral tegmental area are more resistant to this degeneration than those in the SNc, though the mechanisms for selective resistance or vulnerability remain poorly understood. A key to elucidating these processes may lie within the subset of DA neurons that corelease glutamate and express the vesicular glutamate transporter VGLUT2. Here, we addressed the potential relationship between VGLUT expression and DA neuronal vulnerability by overexpressing VGLUT in DA neurons of flies and mice. In Drosophila, VGLUT overexpression led to loss of select DA neuron populations. Similarly, expression of VGLUT2 specifically in murine SNc DA neurons led to neuronal loss and Parkinsonian behaviors. Other neuronal cell types showed no such sensitivity, suggesting that DA neurons are distinctively vulnerable to VGLUT2 expression. Additionally, most DA neurons expressed VGLUT2 during development, and coexpression of VGLUT2 with DA markers increased following injury in the adult. Finally, conditional deletion of VGLUT2 made DA neurons more susceptible to Parkinsonian neurotoxins. These data suggest that the balance of VGLUT2 expression is a crucial determinant of DA neuron survival. Ultimately, manipulation of this VGLUT2-dependent process may represent an avenue for therapeutic development.
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Affiliation(s)
| | - Vivien Zell
- Department of Neurosciences, UCSD, La Jolla, California, USA
| | - Zachary J Farino
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | - Michael Villeneuve
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Robin J Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Serge Przedborski
- Department of Neurology, and.,Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Wei Lu
- Synapse and Neural Circuit Research Unit, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Zachary Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Thomas S Hnasko
- Department of Neurosciences, UCSD, La Jolla, California, USA
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11
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Bittencourt S, Ferrazoli E, Valente MF, Romariz S, Janisset NR, Macedo CE, Antonio BDB, Barros V, Mundim M, Porcionatto M, Aarão MC, Miranda MF, Rodrigues AM, de Almeida ACG, Longo BM, Mello LE. Modification of the natural progression of epileptogenesis by means of biperiden in the pilocarpine model of epilepsy. Epilepsy Res 2017; 138:88-97. [DOI: 10.1016/j.eplepsyres.2017.10.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 10/11/2017] [Accepted: 10/27/2017] [Indexed: 10/18/2022]
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12
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Changes in corticocortical and corticohippocampal network during absence seizures in WAG/Rij rats revealed with time varying Granger causality. Epilepsy Behav 2016; 64:44-50. [PMID: 27728902 DOI: 10.1016/j.yebeh.2016.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/08/2016] [Accepted: 08/09/2016] [Indexed: 11/23/2022]
Abstract
PURPOSE Spike-and-wave discharges (SWDs) recorded in the cortical EEGs of WAG/Rij rats are the hallmark for absence epilepsy in this model. Although this type of epilepsy was long regarded as a form of primary generalized epilepsy, it is now recognized that there is an initiation zone - the perioral region of the somatosensory cortex. However, networks involved in spreading the seizure are not yet fully known. Previously, the dynamics of coupling between different layers of the perioral cortical region and between these zones and different thalamic nuclei was studied in time windows around the SWDs, using nonlinear Granger causality. The aim of the present study was to investigate, using the same method, the coupling dynamics between different regions of the cortex and between these regions and the hippocampus. METHODS Local field potentials were recorded in the frontal, parietal, and occipital cortices and in the hippocampus of 19 WAG/Rij rats. To detect changes in coupling reliably in a short time window, in order to provide a good temporal resolution, the innovative adapted time varying nonlinear Granger causality method was used. Mutual information function was calculated in addition to validate outcomes. Results of both approaches were tested for significance. RESULTS The SWD initiation process was revealed as an increase in intracortical interactions starting from 3.5s before the onset of electrographic seizure. The earliest preictal increase in coupling was directed from the frontal cortex to the parietal cortex. Then, the coupling became bidirectional, followed by the involvement of the occipital cortex (1.5s before SWD onset). There was no driving from any cortical region to hippocampus, but a slight increase in coupling from hippocampus to the frontoparietal cortex was observed just before SWD onset. After SWD onset, an abrupt drop in coupling in all studied pairs was observed. In most of the pairs, the decoupling rapidly disappeared, but driving force from hippocampus and occipital cortex to the frontoparietal cortex was reduced until the SWD termination. CONCLUSION Involvement of multiple cortical regions in SWD initiation shows the fundamental role of corticocortical feedback loops, forming coupling architecture and triggering the generalized seizure. The results add to the ultimate aim to construct a complete picture of brain interactions preceding and accompanying absence seizures in rats.
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Çavdar S, Özgür M, Kirazlı Ö, Karahüseyinoğlu S, Onat F. Comparing glutamatergic neuron population in the mediodorsal thalamic nucleus of genetic absence epilepsy rats from strasbourg (GAERS) and normal control Wistar rats. J Chem Neuroanat 2016; 77:93-99. [PMID: 27262783 DOI: 10.1016/j.jchemneu.2016.05.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 05/30/2016] [Accepted: 05/30/2016] [Indexed: 11/17/2022]
Abstract
An imbalance between GABAergic inhibition and glutamatergic excitation is suspected to play a role in the genesis of epileptic processes. In the present study we quantified the number of glutamate+ve neurons in the mediodorsal thalamic nucleus (MD) of genetic absence epilepsy rats from Strasbourg (GAERS) and compared these with values for normal Wistar rats. The MD thalamic nucleus was removed from each animal and the glutamatergic neurons were labelled using light-microscopy glutamate immunohistochemistry. The disector method was used to quantify the glutamate+ve neurons in the MD thalamic nucleus of GAERS and Wistar rats. The data were statistically analyzed. In the Wistar animals glutamate+ve neurons formed 89% and in GAERS 92.3% of the total neurons in 1000μm3 of MD thalamic nucleus. In GAERS glutamate+ve neurons showed statistically significant increase in the MD thalamic nucleus compared to Wistar animals. In Wistar animals the glutamate-ve neurons formed 11% and in GAERS 7.7% of the total neurons in 1000μm3 of MD thalamic. No significant difference was observed in glutamate-ve neurons between the two strains. The average diameter of glutamate+ve neurons showed no significance, while glutamate-ve neurons were significant between the two strains. The results of the present study, on genetic absence epilepsy model, GAERS, confirms the role of MD thalamic nucleus in chemically induced absence epilepsy.
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Affiliation(s)
- Safiye Çavdar
- Department of Anatomy, School of Medicine, Koç University, Sarıyer, Istanbul, Turkey.
| | - Merve Özgür
- Department of Anatomy, School of Medicine, Koç University, Sarıyer, Istanbul, Turkey
| | - Özlem Kirazlı
- Department of Anatomy, School of Medicine, Marmara University, Istanbul, Turkey
| | - Serçin Karahüseyinoğlu
- Department of Histology-Embryology, School of Medicine, Koç University, Sarıyer, Istanbul, Turkey
| | - Filiz Onat
- Department of Pharmacology and Clinic Pharmacology, School of Medicine, Marmara University, Istanbul, Turkey
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14
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Marignier R, Ruiz A, Cavagna S, Nicole A, Watrin C, Touret M, Parrot S, Malleret G, Peyron C, Benetollo C, Auvergnon N, Vukusic S, Giraudon P. Neuromyelitis optica study model based on chronic infusion of autoantibodies in rat cerebrospinal fluid. J Neuroinflammation 2016; 13:111. [PMID: 27193196 PMCID: PMC4872335 DOI: 10.1186/s12974-016-0577-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/10/2016] [Indexed: 11/19/2022] Open
Abstract
Background Devic’s neuromyelitis optica (NMO) is an autoimmune astrocytopathy, associated with central nervous system inflammation, demyelination, and neuronal injury. Several studies confirmed that autoantibodies directed against aquaporin-4 (AQP4-IgG) are relevant in the pathogenesis of NMO, mainly through complement-dependent toxicity leading to astrocyte death. However, the effect of the autoantibody per se and the exact role of intrathecal AQP4-IgG are still controversial. Methods To explore the intrinsic effect of intrathecal AQP4-IgG, independent from additional inflammatory effector mechanisms, and to evaluate its clinical impact, we developed a new animal model, based on a prolonged infusion of purified immunoglobulins from NMO patient (IgGAQP4+, NMO-rat) and healthy individual as control (Control-rat) in the cerebrospinal fluid (CSF) of live rats. Results We showed that CSF infusion of purified immunoglobulins led to diffusion in the brain, spinal cord, and optic nerves, the targeted structures in NMO. This was associated with astrocyte alteration in NMO-rats characterized by loss of aquaporin-4 expression in the spinal cord and the optic nerves compared to the Control-rats (p = 0.001 and p = 0.02, respectively). In addition, glutamate uptake tested on vigil rats was dramatically reduced in NMO-rats (p = 0.001) suggesting that astrocytopathy occurred in response to AQP4-IgG diffusion. In parallel, myelin was altered, as shown by the decrease of myelin basic protein staining by up to 46 and 22 % in the gray and white matter of the NMO-rats spinal cord, respectively (p = 0.03). Loss of neurofilament positive axons in NMO-rats (p = 0.003) revealed alteration of axonal integrity. Then, we investigated the clinical consequences of such alterations on the motor behavior of the NMO-rats. In a rotarod test, NMO-rats performance was lower compared to the controls (p = 0.0182). AQP4 expression, and myelin and axonal integrity were preserved in AQP4-IgG-depleted condition. We did not find a major immune cell infiltration and microglial activation nor complement deposition in the central nervous system, in our model. Conclusions We establish a link between motor-deficit, NMO-like lesions and astrocytopathy mediated by intrathecal AQP4-IgG. Our study validates the concept of the intrinsic effect of autoantibody against surface antigens and offers a model for testing antibody and astrocyte-targeted therapies in NMO. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0577-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- R Marignier
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France. .,Université Lyon 1, Université de Lyon, Lyon, France. .,Service de Neurologie A, Eugène Devic EDMUS Foundation Against Multiple Sclerosis, Observatoire Français de la Sclérose en Plaques, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, 59 Boulevard Pinel, 69677, Lyon-Bron cedex, France.
| | - A Ruiz
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
| | - S Cavagna
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
| | - A Nicole
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France
| | - C Watrin
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
| | - M Touret
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
| | - S Parrot
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
| | - G Malleret
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
| | - C Peyron
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
| | - C Benetollo
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
| | - N Auvergnon
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
| | - S Vukusic
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France.,Service de Neurologie A, Eugène Devic EDMUS Foundation Against Multiple Sclerosis, Observatoire Français de la Sclérose en Plaques, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, 59 Boulevard Pinel, 69677, Lyon-Bron cedex, France
| | - P Giraudon
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France.,Université Lyon 1, Université de Lyon, Lyon, France
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15
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16
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Verma P, Augustine GJ, Ammar MR, Tashiro A, Cohen SM. A neuroprotective role for microRNA miR-1000 mediated by limiting glutamate excitotoxicity. Nat Neurosci 2015; 18:379-85. [PMID: 25643297 DOI: 10.1038/nn.3935] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 01/06/2015] [Indexed: 12/17/2022]
Abstract
Evidence has begun to emerge for microRNAs as regulators of synaptic signaling, specifically acting to control postsynaptic responsiveness during synaptic transmission. In this report, we provide evidence that Drosophila melanogaster miR-1000 acts presynaptically to regulate glutamate release at the synapse by controlling expression of the vesicular glutamate transporter (VGlut). Genetic deletion of miR-1000 led to elevated apoptosis in the brain as a result of glutamatergic excitotoxicity. The seed-similar miR-137 regulated VGluT2 expression in mouse neurons. These conserved miRNAs share a neuroprotective function in the brains of flies and mice. Drosophila miR-1000 showed activity-dependent expression, which might serve as a mechanism to allow neuronal activity to fine-tune the strength of excitatory synaptic transmission.
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Affiliation(s)
- Pushpa Verma
- 1] Institute of Molecular and Cell Biology, Singapore. [2] Department of Biological Sciences, National University of Singapore, Singapore
| | - George J Augustine
- 1] Institute of Molecular and Cell Biology, Singapore. [2] Duke-NUS Graduate Medical School, Singapore. [3] Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, Republic of Korea. [4] Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Mohamed-Raafet Ammar
- 1] Warwick-Nanyang Technological University Neuroscience Programme, School of Biological Sciences, Nanyang Technological University, Singapore. [2] School of Life Sciences, University of Warwick, Coventry, UK
| | - Ayumu Tashiro
- 1] Warwick-Nanyang Technological University Neuroscience Programme, School of Biological Sciences, Nanyang Technological University, Singapore. [2] School of Life Sciences, University of Warwick, Coventry, UK
| | - Stephen M Cohen
- 1] Institute of Molecular and Cell Biology, Singapore. [2] Department of Biological Sciences, National University of Singapore, Singapore
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Crunelli V, Carmignoto G, Steinhäuser C. Novel astrocyte targets: new avenues for the therapeutic treatment of epilepsy. Neuroscientist 2015; 21:62-83. [PMID: 24609207 PMCID: PMC4361461 DOI: 10.1177/1073858414523320] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
During the last 20 years, it has been well established that a finely tuned, continuous crosstalk between neurons and astrocytes not only critically modulates physiological brain functions but also underlies many neurological diseases. In particular, this novel way of interpreting brain activity is markedly influencing our current knowledge of epilepsy, prompting a re-evaluation of old findings and guiding novel experimentation. Here, we review recent studies that have unraveled novel and unique contributions of astrocytes to the generation and spread of convulsive and nonconvulsive seizures and epileptiform activity. The emerging scenario advocates an overall framework in which a dynamic and reciprocal interplay among astrocytic and neuronal ensembles is fundamental for a fuller understanding of epilepsy. In turn, this offers novel astrocytic targets for the development of those really novel chemical entities for the control of convulsive and nonconvulsive seizures that have been acknowledged as a key priority in the management of epilepsy.
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Affiliation(s)
- Vincenzo Crunelli
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, UK
| | - Giorgio Carmignoto
- Centro Nazionale della Ricerca, Neuroscience Institute and Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
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18
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Tamura Y, Ogita K, Ueda T. A new VGLUT-specific potent inhibitor: pharmacophore of Brilliant Yellow. Neurochem Res 2014; 39:117-28. [PMID: 24248859 PMCID: PMC4025951 DOI: 10.1007/s11064-013-1196-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 11/05/2013] [Accepted: 11/07/2013] [Indexed: 10/26/2022]
Abstract
The increased concentration of glutamate in synaptic vesicles, mediated by the vesicular glutamate transporter (VGLUT), is an initial vital step in glutamate synaptic transmission. Evidence indicates that aberrant overexpression of VGLUT is involved in certain pathophysiologies of the central nervous system. VGLUT is subject to inhibition by various types of agents. The most potent VGLUT-specific inhibitor currently known is Trypan Blue, which is highly charged, hence membrane-impermeable. We have sought a potent, VGLUT-specific agent amenable to easy modification to a membrane-permeable analog. We provide evidence that Brilliant Yellow exhibits potent, VGLUT-specific inhibition, with a Ki value of 12 nM. Based upon structure-activity relationship studies and molecular modeling, we have defined the potent inhibitory pharmacophore of Brilliant Yellow. This study provides new insight into development of a membrane-permeable agent to lead to specific blockade, with high potency, of accumulation of glutamate into synaptic vesicles in neurons.
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Affiliation(s)
- Yutaka Tamura
- Molecular and Behavioral Neuroscience Institute, Medical School, The University of Michigan, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109-2200, USA
| | - Kiyokazu Ogita
- Molecular and Behavioral Neuroscience Institute, Medical School, The University of Michigan, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109-2200, USA
| | - Tetsufumi Ueda
- Molecular and Behavioral Neuroscience Institute, Medical School, The University of Michigan, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109-2200, USA
- Department of Pharmacology, Medical School, The University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Psychiatry, Medical School, The University of Michigan, Ann Arbor, Michigan 48109, USA
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19
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Hui Yin Y, Ahmad N, Makmor-Bakry M. Pathogenesis of epilepsy: challenges in animal models. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2013; 16:1119-32. [PMID: 24494063 PMCID: PMC3909622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 08/02/2013] [Indexed: 11/13/2022]
Abstract
Epilepsy is one of the most common chronic disorders affecting individuals of all ages. A greater understanding of pathogenesis in epilepsy will likely provide the basis fundamental for development of new antiepileptic therapies that aim to prevent the epileptogenesis process or modify the progression of epilepsy in addition to treatment of epilepsy symptomatically. Therefore, several investigations have embarked on advancing knowledge of the mechanism underlying epileptogenesis, understanding in mechanism of pharmacoresistance and discovering antiepileptogenic or disease-modifying therapy. Animal models play a crucial and significant role in providing additional insight into mechanism of epileptogenesis. With the help of these models, epileptogenesis process has been demonstrated to be involved in various molecular and biological pathways or processes. Hence, this article will discuss the known and postulated mechanisms of epileptogenesis and challenges in using the animal models.
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Affiliation(s)
- Yow Hui Yin
- Faculty of Pharmacy, University Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Nurulumi Ahmad
- Faculty of Pharmacy, University Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Mohd Makmor-Bakry
- Faculty of Pharmacy, University Kebangsaan Malaysia, Kuala Lumpur, Malaysia,Corresponding author: Mohd Makmor-Bakry. Faculty of Pharmacy, University Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia. Tel: +60392897244; Fax: +60326983271;
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20
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Van Liefferinge J, Massie A, Portelli J, Di Giovanni G, Smolders I. Are vesicular neurotransmitter transporters potential treatment targets for temporal lobe epilepsy? Front Cell Neurosci 2013; 7:139. [PMID: 24009559 PMCID: PMC3757300 DOI: 10.3389/fncel.2013.00139] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 08/11/2013] [Indexed: 12/18/2022] Open
Abstract
The vesicular neurotransmitter transporters (VNTs) are small proteins responsible for packing synaptic vesicles with neurotransmitters thereby determining the amount of neurotransmitter released per vesicle through fusion in both neurons and glial cells. Each transporter subtype was classically seen as a specific neuronal marker of the respective nerve cells containing that particular neurotransmitter or structurally related neurotransmitters. More recently, however, it has become apparent that common neurotransmitters can also act as co-transmitters, adding complexity to neurotransmitter release and suggesting intriguing roles for VNTs therein. We will first describe the current knowledge on vesicular glutamate transporters (VGLUT1/2/3), the vesicular excitatory amino acid transporter (VEAT), the vesicular nucleotide transporter (VNUT), vesicular monoamine transporters (VMAT1/2), the vesicular acetylcholine transporter (VAChT) and the vesicular γ-aminobutyric acid (GABA) transporter (VGAT) in the brain. We will focus on evidence regarding transgenic mice with disruptions in VNTs in different models of seizures and epilepsy. We will also describe the known alterations and reorganizations in the expression levels of these VNTs in rodent models for temporal lobe epilepsy (TLE) and in human tissue resected for epilepsy surgery. Finally, we will discuss perspectives on opportunities and challenges for VNTs as targets for possible future epilepsy therapies.
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21
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Vasylieva N, Maucler C, Meiller A, Viscogliosi H, Lieutaud T, Barbier D, Marinesco S. Immobilization Method to Preserve Enzyme Specificity in Biosensors: Consequences for Brain Glutamate Detection. Anal Chem 2013; 85:2507-15. [DOI: 10.1021/ac3035794] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Natalia Vasylieva
- University Claude Bernard Lyon 1, Lyon, F-69000, France
- Institut de Nanotechnologie
de Lyon, CNRS UMR-5270, INSA de Lyon, France
| | | | - Anne Meiller
- University Claude Bernard Lyon 1, Lyon, F-69000, France
| | - Henry Viscogliosi
- Service Central d’Analyse, CNRS UMR-5280−Echangeur de Solaize, Solaize,
FRANCE
| | | | - Daniel Barbier
- Institut de Nanotechnologie
de Lyon, CNRS UMR-5270, INSA de Lyon, France
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22
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Crunelli V, Carmignoto G. New vistas on astroglia in convulsive and non-convulsive epilepsy highlight novel astrocytic targets for treatment. J Physiol 2012; 591:775-85. [PMID: 23230232 DOI: 10.1113/jphysiol.2012.243378] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Our current knowledge of the role of astrocytes in health and disease states supports the view that many physiological brain functions and neurological diseases are finely tuned, and in certain cases fully determined, by the continuous cross-talk between astrocytes and neurons. This novel way of interpreting brain activity as a dynamic and reciprocal interplay between astrocytic and neuronal networks has also influenced our understanding of epilepsy, not only forcing a reinterpretation of old findings, but also being a catalyst for novel experimentation. In this review, we summarize some of the recent studies that highlight these novel distinct contributions of astrocytes to the expression of convulsive and non-convulsive epileptiform discharges and seizures. The emerging picture suggests a general framework based on bilateral signalling between astrocytes and neurons for a fuller understanding of epileptogenic and epileptic mechanisms in the brain network. Astrocytes potentially represent targets for the development of those novel chemical entities with improved efficacy for the treatment of convulsive and non-convulsive epilepsy that expert groups have recognized as one of the key priorities for the management of epilepsy.
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Affiliation(s)
- Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
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23
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Pirttimaki T, Parri HR, Crunelli V. Astrocytic GABA transporter GAT-1 dysfunction in experimental absence seizures. J Physiol 2012; 591:823-33. [PMID: 23090943 DOI: 10.1113/jphysiol.2012.242016] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
An enhanced tonic GABA(A) inhibition in the thalamus plays a crucial role in experimental absence seizures and has been attributed, on the basis of indirect evidence, to a dysfunction of the astrocytic GABA transporter-1 (GAT-1). Here, the GABA transporter current was directly investigated in thalamic astrocytes from a well-established genetic model of absence seizures, the genetic absence epilepsy rats from Strasbourg (GAERS), and its non-epileptic control (NEC) strain. We also characterized the novel form of GABAergic and glutamatergic astrocyte-to-neuron signalling by recording slow outward currents (SOCs) and slow inward currents (SICs), respectively, in thalamocortical (TC) neurons of both strains. In patch-clamped astrocytes, the GABA transporter current was abolished by combined application of the selective GAT-1 and GAT-3 blocker, NO711 (30 μm) and SNAP5114 (60 μm), respectively, to GAERS and NEC thalamic slices. NO711 alone significantly reduced (41%) the transporter current in NEC, but had no effect in GAERS. SNAP5114 alone reduced by half the GABA transporter current in NEC, whilst it abolished it in GAERS. SIC properties did not differ between GAERS and NEC TC neurons, whilst moderate changes in SOC amplitude and kinetics were observed. These data provide the first direct demonstration of a malfunction of the astrocytic thalamic GAT-1 transporter in absence epilepsy and support an abnormal astrocytic modulation of thalamic ambient GABA levels. Moreover, while the glutamatergic astrocyte-neuron signalling is unaltered in the GAERS thalamus, the changes in some properties of the GABAergic astrocyte-neuron signalling in this epileptic strain may contribute to the generation of absence seizures.
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Affiliation(s)
- Tiina Pirttimaki
- Neuroscience Division, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
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24
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Lin LH, Nitschke Dragon D, Talman WT. Collateral damage and compensatory changes after injection of a toxin targeting neurons with the neurokinin-1 receptor in the nucleus tractus solitarii of rat. J Chem Neuroanat 2012; 43:141-8. [PMID: 22414622 DOI: 10.1016/j.jchemneu.2012.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 02/23/2012] [Accepted: 02/24/2012] [Indexed: 02/02/2023]
Abstract
Injection into the nucleus tractus solitarii (NTS) of toxins that target substance P (SP) receptors ablates neurons that express neurokinin-1 (NK1) receptors, attenuates baroreflexes, and results in increased lability of arterial pressure. We and others have shown that the toxin leads to loss of neurons containing SP receptors and loss of GABAergic neurons in the NTS; but given that neither type neuron is thought to be integral to baroreflex transmission in NTS, mechanisms responsible for the cardiovascular changes remained unclear. Because NK1 receptors colocalize with N-methyl-d-aspartate (NMDA) receptors and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in NTS and because glutamate transmission may be integral to baroreflex transmission in the NTS we hypothesized that the toxic lesions may interrupt mechanisms for glutamate transmission. Interruption of those mechanisms could be responsible for the cardiovascular effects. We tested the hypothesis by performing fluorescent immunohistochemistry, confocal microscopy and image analysis after injecting stabilized SP-SAP (SSP-SAP) unilaterally into the NTS. We assessed changes in immunoreactivity (IR) of NMDA receptor subunit 1 (NMDAR1), AMPA receptor subunit 2 (GluR2), and 3 types of vesicular glutamate transporters (VGluT) as well as IR of gamma-aminobutyric acid receptors type b (GABAb), neuronal nitric oxide synthase (nNOS), tyrosine hydroxylase (TH), and protein gene product 9.5 (PGP 9.5), a neuronal marker, in the NTS. When compared to that of the same section of the un-injected NTS, IR decreased significantly in the injected side for NMDAR1 (p<0.01), GluR2 (p<0.01), VGluT3 (p<0.01), GABAb (p<0.001), and PGP9.5 (p<0.001). In contrast, IR for VGluT1 (p<0.001), VGluT2 (p<0.001), nNOS (p<0.001), and TH (p<0.001) increased significantly. We conclude that pathologic effects following ablation of neurons with NK1 receptors in NTS may result from interruption of neurotransmission through other neurochemical systems associated with NK1 receptors-containing neurons.
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Affiliation(s)
- Li-Hsien Lin
- Department of Neurology, University of Iowa, Iowa City, IA 52242, USA
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25
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Jones NC, O’Brien TJ, Powell KL. Morphometric changes and molecular mechanisms in rat models of idiopathic generalized epilepsy with absence seizures. Neurosci Lett 2011; 497:185-93. [DOI: 10.1016/j.neulet.2011.02.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 01/21/2011] [Accepted: 02/15/2011] [Indexed: 01/29/2023]
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Daniels RW, Miller BR, DiAntonio A. Increased vesicular glutamate transporter expression causes excitotoxic neurodegeneration. Neurobiol Dis 2010; 41:415-20. [PMID: 20951206 DOI: 10.1016/j.nbd.2010.10.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 09/03/2010] [Accepted: 10/07/2010] [Indexed: 11/19/2022] Open
Abstract
Increases in vesicular glutamate transporter (VGLUT) levels are observed after a variety of insults including hypoxic injury, stress, methamphetamine treatment, and in genetic seizure models. Such overexpression can cause an increase in the amount of glutamate released from each vesicle, but it is unknown whether this is sufficient to induce excitotoxic neurodegeneration. Here we show that overexpression of the Drosophila vesicular glutamate transporter (DVGLUT) leads to excess glutamate release, with some vesicles releasing several times the normal amount of glutamate. Increased DVGLUT expression also leads to an age-dependent loss of motor function and shortened lifespan, accompanied by a progressive neurodegeneration in the postsynaptic targets of the DVGLUT-overexpressing neurons. The early onset lethality, behavioral deficits, and neuronal pathology require overexpression of a functional DVGLUT transgene. Thus overexpression of DVGLUT is sufficient to generate excitotoxic neuropathological phenotypes and therefore reducing VGLUT levels after nervous system injury or stress may mitigate further damage.
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Affiliation(s)
- Richard W Daniels
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Marignier R, Nicolle A, Watrin C, Touret M, Cavagna S, Varrin-Doyer M, Cavillon G, Rogemond V, Confavreux C, Honnorat J, Giraudon P. Oligodendrocytes are damaged by neuromyelitis optica immunoglobulin G via astrocyte injury. ACTA ACUST UNITED AC 2010; 133:2578-91. [PMID: 20688809 DOI: 10.1093/brain/awq177] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Devic's neuromyelitis optica is an inflammatory demyelinating disorder normally restricted to the optic nerves and spinal cord. Since the identification of a specific autoantibody directed against aquaporin 4, neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody, neuromyelitis optica has been considered an entity distinct from multiple sclerosis. Recent findings indicate that the neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody has a pathogenic role through complement-dependent astrocyte toxicity. However, the link with demyelination remains elusive. Autoantibodies can act as receptor agonists/antagonists or alter antigen density in their target cells. We hypothesized that the neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody impairs astrocytic function and secondarily leads to demyelination. Rat astrocytes and oligodendrocytes from primary cultures and rat optic nerves were exposed long-term (24 h) to immunoglobulin G in the absence of complement. Immunoglobulin G was purified from the serum of patients with neuromyelitis optica who were either neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody positive or negative, as well as from healthy controls. Flow cytometry analysis showed a reduction of membrane aquaporin 4 and glutamate transporter type 1 on astrocytes following contact with immunoglobulin G purified from neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody positive serum only. The activity of glutamine synthetase, an astrocyte enzyme converting glutamate into glutamine, decreased in parallel, indicating astrocyte dysfunction. Treatment also reduced oligodendrocytic cell processes and approximately 30% oligodendrocytes died. This deleterious effect was confirmed ex vivo; exposed optic nerves showed reduction of myelin basic protein. Immunoglobulin G from neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody seronegative patients and from healthy controls had no similar effect. Neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody did not directly injure oligodendrocytes cultured without astrocytes. A toxic bystander effect of astrocytes damaged by neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody on oligodendrocytes was identified. Progressive accumulation of glutamate in the culture medium of neuromyelitis optica-immunoglobulin G/aquaporin 4-antibody-treated glial cells supported the hypothesis of a glutamate-mediated excitotoxic death of oligodendrocytes in our models. Moreover, co-treatment of glial cultures with neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody and d+2-amino-5-phosphonopentanoic acid, a competitive antagonist at the N-methyl-d-aspartate/glutamate receptor, partially protected oligodendrocytes. Co-immunolabelling of oligodendrocyte markers and neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody showed that astrocytic positive processes were in close contact with oligodendrocytes and myelin in rat optic nerves and spinal cord, but far less so in other parts of the central nervous system. This suggests a bystander effect of neuromyelitis optica-immunoglobulin G-damaged astrocytes on oligodendrocytes in the nervous tissues affected by neuromyelitis optica. In conclusion, in these cell culture models we found a direct, complement-independent effect of neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody on astrocytes, with secondary damage to oligodendrocytes possibly resulting from glutamate-mediated excitotoxicity. These mechanisms could add to the complement-induced damage, particularly the demyelination, seen in vivo.
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Affiliation(s)
- Romain Marignier
- Service de Neurologie A and EDMUS Coordinating Centre, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France
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Muhle H, von Spiczak S, Gaus V, Kara S, Helbig I, Hampe J, Franke A, Weber Y, Lerche H, Kleefuss-Lie AA, Elger CE, Schreiber S, Stephani U, Sander T. Role of GRM4 in idiopathic generalized epilepsies analysed by genetic association and sequence analysis. Epilepsy Res 2010; 89:319-26. [PMID: 20338729 DOI: 10.1016/j.eplepsyres.2010.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 02/02/2010] [Accepted: 02/14/2010] [Indexed: 01/12/2023]
Abstract
BACKGROUND GRM4 encoding the group III metabotropic glutamate receptor 4 (mGluR4), is located on the chromosomal segment 6p21.3 where tentative susceptibility loci for Juvenile Myoclonic Epilepsy (JME) and Photoparoxysmal Response (PPR) have been mapped. The present candidate gene study examined if variation in GRM4 confers susceptibility to IGE. PATIENTS AND METHODS The case-control association sample included 564 unrelated IGE patients and 733 population controls of German descent. Association analysis was carried out for 17 single nucleotide polymorphisms (SNPs) covering the genomic GRM4 sequence for all IGE patients as well as for two common IGE subsyndromes [Juvenile Myoclonic Epilepsy (JME, n=215) and Childhood Absence Epilepsy (CAE, n=175)]. Sequence analysis was performed in 85 IGE and 42 PPR cases and 44 controls. RESULTS Nominally significant associations were detected between IGE and seven GRM4 SNPs (with P-values ranging from 0.037 to 0.0036), between JME and five SNPs (P=0.042-0.0106), and between CAE and two SNPs (P=0.0466-0.0021). Four novel SNPs were identified by sequence analysis. CONCLUSIONS Our association findings support the hypothesis that GRM4 sequence variants might confer low-risk effects to the etiology of IGE. A minor pathogenetic contribution of the examined variants is possible. These exploratory findings warrant further replication analyses.
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Affiliation(s)
- Hiltrud Muhle
- Department of Neuropediatrics, University Hospital of Kiel, Schwanenweg 20, 24105 Kiel, Germany.
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D’Alimonte I, D’Auro M, Citraro R, Biagioni F, Jiang S, Nargi E, Buccella S, Di Iorio P, Giuliani P, Ballerini P, Caciagli F, Russo E, De Sarro G, Ciccarelli R. Altered distribution and function of A2Aadenosine receptors in the brain of WAG/Rij rats with genetic absence epilepsy, before and after appearance of the disease. Eur J Neurosci 2009; 30:1023-35. [DOI: 10.1111/j.1460-9568.2009.06897.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Nehlig A, Dufour F, Klinger M, Willing LB, Simpson IA, Vannucci SJ. The ketogenic diet has no effect on the expression of spike-and-wave discharges and nutrient transporters in genetic absence epilepsy rats from Strasbourg. J Neurochem 2009; 109 Suppl 1:207-13. [PMID: 19393029 DOI: 10.1111/j.1471-4159.2009.05938.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The genetic absence epilepsy rat from Strasbourg is considered an isomorphic, predictive, and homologous model of typical childhood absence epilepsy. It is characterized by the expression of spike-and-wave discharges (SWDs) in the thalamus and cortex. The ketogenic diet (KD) is successfully used in humans and animals with various types of seizures, but was not effective in children with intractable atypical absence epilepsy. Here, we studied its potential impact on the occurrence of SWDs in genetic absence epilepsy rat from Strasbourg. Rats were fed the KD for 3 weeks during which they were regularly subjected to the electroencephalographic recording of SWDs. The KD did not influence the number and duration of SWDs despite a 15-22% decrease in plasma glucose levels and a large increase in beta-hydroxybutyrate levels. Likewise, the KD did not affect the level of expression of the blood-brain barrier glucose transporter GLUT1 or of the monocarboxylate transporters, MCT1 and MCT2. This report extends the observation in humans that the KD does not appear to show effectiveness in intractable atypical absence epilepsy to this model of typical childhood absence epilepsy which responds to specific antiepileptic drugs.
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Schallier A, Massie A, Loyens E, Moechars D, Drinkenburg W, Michotte Y, Smolders I. vGLUT2 heterozygous mice show more susceptibility to clonic seizures induced by pentylenetetrazol. Neurochem Int 2009; 55:41-4. [PMID: 19171171 DOI: 10.1016/j.neuint.2008.12.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Accepted: 12/13/2008] [Indexed: 11/26/2022]
Abstract
Glutamate, the most abundant excitatory neurotransmitter in the central nervous system, is well known to be implicated in epileptic seizures. Therefore, impairments in glutamate transport could have an involvement in the mechanism of epileptogenesis. The uptake of glutamate into synaptic vesicles is mediated by vesicular glutamate transporters (vGLUTs). There are three known vGLUT isoforms, vGLUT1-3. In this study, we are particularly interested in the vGLUT2 isoform. We investigated the possible role of vGLUT2 in pentylenetetrazol (PTZ)-induced seizure generation. Seizure threshold of PTZ was compared in vGLUT2 heterozygous knock out (HET) and wild type (WT) mice. In comparison with their WT littermates a lower dose of PTZ was needed in the vGLUT2 HET mice until the onset of the first myoclonic jerk. The threshold for PTZ-induced clonic seizure activity was also lower in the vGLUT2 HET mice. These results indicate, for the first time, that vGLUT2 is likely involved in the epileptogenesis of generalized seizures.
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Affiliation(s)
- Anneleen Schallier
- Department of Pharmaceutical Chemistry, Research Group Experimental Pharmacology, Vrije Universiteit Brussel, Brussels, Belgium
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