1
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Wu Y, Luo XD, Xiang T, Li SJ, Ma MG, Chen ML. Activation of metabotropic glutamate receptor 1 regulates hippocampal CA1 region excitability in rats with status epilepticus by suppressing the HCN1 channel. Neural Regen Res 2023; 18:594-602. [DOI: 10.4103/1673-5374.350206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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2
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Kumar K, Banerjee Dixit A, Tripathi M, Dubey V, Siraj F, Sharma MC, Lalwani S, Chandra PS, Banerjee J. Transcriptomic profiling of nonneoplastic cortical tissues reveals epileptogenic mechanisms in dysembryoplastic neuroepithelial tumors. Funct Integr Genomics 2022; 22:905-917. [PMID: 35633443 DOI: 10.1007/s10142-022-00869-1] [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: 09/19/2021] [Revised: 05/09/2022] [Accepted: 05/09/2022] [Indexed: 11/29/2022]
Abstract
Low-grade dysembryoplastic neuroepithelial tumors (DNTs) are a frequent cause of drug-refractory epilepsy. Molecular mechanisms underlying seizure generation in these tumors are poorly understood. This study was conducted to identify altered genes in nonneoplastic epileptogenic cortical tissues (ECTs) resected from DNT patients during electrocorticography (ECoG)-guided surgery. RNA sequencing (RNAseq) was used to determine the differentially expressed genes (DEGs) in these high-spiking ECTs compared to non-epileptic controls. A total of 477 DEGs (180 upregulated; 297 downregulated) were observed in the ECTs compared to non-epileptic controls. Gene ontology analysis revealed enrichment of genes belonging to the following Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways: (i) glutamatergic synapse; (ii) nitrogen metabolism; (iii) transcriptional misregulation in cancer; and (iv) protein digestion and absorption. The glutamatergic synapse pathway was enriched by DEGs such as GRM4, SLC1A6, GRIN2C, GRM2, GRM5, GRIN3A, and GRIN2B. Enhanced glutamatergic activity was observed in the pyramidal neurons of ECTs, which could be attributed to altered synaptic transmission in these tissues compared to non-epileptic controls. Besides glutamatergic synapse, altered expression of other genes such as GABRB1 (synapse formation), SLIT2 (axonal growth), and PROKR2 (neuron migration) could be linked to epileptogenesis in ECTs. Also, upregulation of GABRA6 gene in ECTs could underlie benzodiazepine resistance in these patients. Neural cell-type-specific gene set enrichment analysis (GSEA) revealed transcriptome of ECTs to be predominantly contributed by microglia and neurons. This study provides first comprehensive gene expression profiling of nonneoplastic ECTs of DNT patients and identifies genes/pathways potentially linked to epileptogenesis.
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Affiliation(s)
- Krishan Kumar
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | | | | | - Vivek Dubey
- Department of Biophysics, All India Institute of Medical Sciences (AIIMS), New Delhi, 110029, India
| | - Fouzia Siraj
- ICMR-National Institute of Pathology, New Delhi, India
| | | | - Sanjeev Lalwani
- Department of Forensic Medicine and Toxicology, AIIMS, New Delhi, India
| | | | - Jyotirmoy Banerjee
- Department of Biophysics, All India Institute of Medical Sciences (AIIMS), New Delhi, 110029, India.
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3
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Turati J, Rudi J, Beauquis J, Carniglia L, López Couselo F, Saba J, Caruso C, Saravia F, Lasaga M, Durand D. A metabotropic glutamate receptor 3 (mGlu3R) isoform playing neurodegenerative roles in astrocytes is prematurely up-regulated in an Alzheimer's model. J Neurochem 2022; 161:366-382. [PMID: 35411603 DOI: 10.1111/jnc.15610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/14/2022] [Accepted: 03/23/2022] [Indexed: 12/26/2022]
Abstract
Subtype 3 metabotropic glutamate receptor (mGlu3R) displays a broad range of neuroprotective effects. We previously demonstrated that mGlu3R activation in astrocytes protects hippocampal neurons from Aβ neurotoxicity through stimulation of both neurotrophin release and Aβ uptake. Alternative-spliced variants of mGlu3R were found in human brains. The most prevalent variant, mGlu3Δ4, lacks exon 4 encoding the transmembrane domain and can inhibit ligand binding to mGlu3R. To date, neither its role in neurodegenerative disorders nor its endogenous expression in CNS cells has been addressed. The present paper describes for the first time an association between altered hippocampal expression of mGlu3Δ4 and Alzheimer's disease (AD) in the preclinical murine model PDAPP-J20, as well as a deleterious effect of mGlu3Δ4 in astrocytes. As assessed by western blot, hippocampal mGlu3R levels progressively decreased with age in PDAPP-J20 mice. On the contrary, mGlu3Δ4 levels were drastically increased with aging in nontransgenic mice, but prematurely over-expressed in 5-month-old PDAPP-J20-derived hippocampi, prior to massive senile plaque deposition. Also, we found that mGlu3Δ4 co-precipitated with mGlu3R mainly in 5-month-old PDAPP-J20 mice. We further showed by western blot that primary cultured astrocytes and neurons expressed mGlu3Δ4, whose levels were reduced by Aβ, thereby discouraging a causal effect of Aβ on mGlu3Δ4 induction. However, heterologous expression of mGlu3Δ4 in astrocytes induced cell death, inhibited mGlu3R expression, and prevented mGlu3R-dependent Aβ glial uptake. Indeed, mGlu3Δ4 promoted neurodegeneration in neuron-glia co-cultures. These results provide evidence of an inhibitory role of mGlu3Δ4 in mGlu3R-mediated glial neuroprotective pathways, which may lie behind AD onset.
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Affiliation(s)
- Juan Turati
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Julieta Rudi
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.,IATIMET Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Juan Beauquis
- Laboratorio de Neurobiología del Envejecimiento, Instituto de Biología y Medicina Experimental (IBYME), CONICET, Buenos Aires, Argentina.,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lila Carniglia
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Federico López Couselo
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Julieta Saba
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Carla Caruso
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Flavia Saravia
- Laboratorio de Neurobiología del Envejecimiento, Instituto de Biología y Medicina Experimental (IBYME), CONICET, Buenos Aires, Argentina.,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mercedes Lasaga
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Daniela Durand
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
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Czornyj L, Auzmendi J, Lazarowski A. Transporter hypothesis in pharmacoresistant epilepsies Is it at the central or peripheral level? Epilepsia Open 2021; 7 Suppl 1:S34-S46. [PMID: 34542938 PMCID: PMC9340303 DOI: 10.1002/epi4.12537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 12/22/2022] Open
Abstract
The multidrug‐resistance (MDR) phenotype is typically observed in patients with refractory epilepsy (RE) whose seizures are not controlled despite receiving several combinations of more than two antiseizure medications (ASMs) directed against different ion channels or neurotransmitter receptors. Since the use of bromide in 1860, more than 20 ASMs have been developed; however, historically ~30% of cases of RE with MDR phenotype remains unchanged. Irrespective of metabolic biotransformation, the biodistribution of ASMs and their metabolites depends on the functional expression of some ATP‐binding cassette transporters (ABC‐t) in different organs, such as the blood‐brain barrier (BBB), bowel, liver, and kidney, among others. ABC‐t, such as P‐glycoprotein (P‐gp), multidrug resistance–associated protein (MRP‐1), and breast cancer–resistance protein (BCRP), are mainly expressed in excretory organs and play a critical role in the pharmacokinetics (PK) of all drugs. The transporter hypothesis can explain pharmacoresistance to a broad spectrum of ASMs, even when administered simultaneously. Since ABC‐t expression can be induced by hypoxia, inflammation, or seizures, a high frequency of uncontrolled seizures increases the risk of RE. These stimuli can induce ABC‐t expression in excretory organs and in previously non‐expressing (electrically responsive) cells, such as neurons or cardiomyocytes. In this regard, an alternative mechanism to the classical pumping function of P‐gp indicates that P‐gp activity can also produce a significant reduction in resting membrane potential (ΔΨ0 = −60 to −10 mV). P‐gp expression in neurons and cardiomyocytes can produce membrane depolarization and participate in epileptogenesis, heart failure, and sudden unexpected death in epilepsy. On this basis, ABC‐t play a peripheral role in controlling the PK of ASMs and their access to the brain and act at a central level, favoring neuronal depolarization by mechanisms independent of ion channels or neurotransmitters that current ASMs cannot control.
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Affiliation(s)
- Liliana Czornyj
- Neurology Service, "Juan P. Garrahan" National Children's Hospital, Buenos Aires, Argentina
| | - Jerónimo Auzmendi
- Institute for Research in Physiopathology and Clinical Biochemistry (INFIBIOC), Clinical Biochemistry Department, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina.,National Council for Scientific and Technical Research (CONICET), Buenos Aires, Argentina
| | - Alberto Lazarowski
- Institute for Research in Physiopathology and Clinical Biochemistry (INFIBIOC), Clinical Biochemistry Department, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
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Heuser K, Enger R. Astrocytic Ca 2+ Signaling in Epilepsy. Front Cell Neurosci 2021; 15:695380. [PMID: 34335188 PMCID: PMC8320018 DOI: 10.3389/fncel.2021.695380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/16/2021] [Indexed: 01/10/2023] Open
Abstract
Epilepsy is one of the most common neurological disorders – estimated to affect at least 65 million worldwide. Most of the epilepsy research has so far focused on how to dampen neuronal discharges and to explain how changes in intrinsic neuronal activity or network function cause seizures. As a result, pharmacological therapy has largely been limited to symptomatic treatment targeted at neurons. Given the expanding spectrum of functions ascribed to the non-neuronal constituents of the brain, in both physiological brain function and in brain disorders, it is natural to closely consider the roles of astrocytes in epilepsy. It is now widely accepted that astrocytes are key controllers of the composition of the extracellular fluids, and may directly interact with neurons by releasing gliotransmitters. A central tenet is that astrocytic intracellular Ca2+ signals promote release of such signaling substances, either through synaptic or non-synaptic mechanisms. Accruing evidence suggests that astrocytic Ca2+ signals play important roles in both seizures and epilepsy, and this review aims to highlight the current knowledge of the roles of this central astrocytic signaling mechanism in ictogenesis and epileptogenesis.
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Affiliation(s)
- Kjell Heuser
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Rune Enger
- Letten Centre and GliaLab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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Su LD, Wang N, Han J, Shen Y. Group 1 Metabotropic Glutamate Receptors in Neurological and Psychiatric Diseases: Mechanisms and Prospective. Neuroscientist 2021; 28:453-468. [PMID: 34088252 PMCID: PMC9449437 DOI: 10.1177/10738584211021018] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are G-protein coupled receptors
that are activated by glutamate in the central nervous system (CNS).
Basically, mGluRs contribute to fine-tuning of synaptic efficacy and
control the accuracy and sharpness of neurotransmission. Among eight
subtypes, mGluR1 and mGluR5 belong to group 1 (Gp1) family, and are
implicated in multiple CNS disorders, such as Alzheimer’s disease,
autism, Parkinson’s disease, and so on. In the present review, we
systematically discussed underlying mechanisms and prospective of Gp1
mGluRs in a group of neurological and psychiatric diseases, including
Alzheimer’s disease, Parkinson’s disease, autism spectrum disorder,
epilepsy, Huntington’s disease, intellectual disability, Down’s
syndrome, Rett syndrome, attention-deficit hyperactivity disorder,
addiction, anxiety, nociception, schizophrenia, and depression, in
order to provide more insights into the therapeutic potential of Gp1
mGluRs.
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Affiliation(s)
- Li-Da Su
- Neuroscience Care Unit, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Na Wang
- School of Medicine, Zhejiang University City College, Hangzhou, China
| | - Junhai Han
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Ying Shen
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China
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DuBois JM, Mathotaarachchi S, Rousset OG, Sziklas V, Sepulcre J, Guiot MC, Hall JA, Massarweh G, Soucy JP, Rosa-Neto P, Kobayashi E. Large-scale mGluR5 network abnormalities linked to epilepsy duration in focal cortical dysplasia. Neuroimage Clin 2020; 29:102552. [PMID: 33401137 PMCID: PMC7787952 DOI: 10.1016/j.nicl.2020.102552] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/19/2020] [Accepted: 12/21/2020] [Indexed: 12/03/2022]
Abstract
To determine the extent of metabotropic glutamate receptor type 5 (mGluR5) network abnormalities associated with focal cortical dysplasia (FCD), we performed graph theoretical analysis of [11C]ABP688 PET binding potentials (BPND), which allows for quantification of mGluR5 availability. Undirected graphs were constructed for the entire cortex in 17 FCD patients and 33 healthy controls using inter-regional similarity of [11C]ABP688 BPND. We assessed group differences in network integration between healthy controls and the ipsilateral and contralateral hemispheres of FCD patients. Compared to healthy controls, FCD patients showed reduced network efficiency and reduced small-world connectivity. The mGluR5 network of FCD patients was also less resilient to targeted removal of high centrality nodes, suggesting a less integrated network organization. In highly efficient hub nodes of FCD patients, we observed a significant negative correlation between local efficiency and duration of epilepsy only in the contralateral hemisphere, suggesting that some nodes may be more vulnerable to persistent epileptic activity. Our study provides the first in vivo evidence for a widespread reduction in cortical mGluR5 network integration in FCD patients. In addition, we find that ongoing epileptic activity may alter chemoarchitectural brain organization resulting in reduced efficiency in distant regions that are essential for network integration.
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Affiliation(s)
- Jonathan M DuBois
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada.
| | - Sulantha Mathotaarachchi
- Translational Neuroimaging Laboratory, McGill Center for Studies in Aging, Douglas Mental Health University Institute, McGill University, Montreal, Canada
| | - Olivier G Rousset
- Division of Nuclear Medicine and Molecular Imaging, Johns Hopkins University, Baltimore, United States
| | - Viviane Sziklas
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Jorge Sepulcre
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
| | - Marie-Christine Guiot
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada; Department of Pathology, McGill University, Montreal, Canada
| | - Jeffery A Hall
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Gassan Massarweh
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Jean-Paul Soucy
- PET Unit, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Canada; Bio-Imaging Group, PERFORM Centre, Concordia University, Montreal, Canada
| | - Pedro Rosa-Neto
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada; Translational Neuroimaging Laboratory, McGill Center for Studies in Aging, Douglas Mental Health University Institute, McGill University, Montreal, Canada; PET Unit, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada.
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Mühlebner A, Bongaarts A, Sarnat HB, Scholl T, Aronica E. New insights into a spectrum of developmental malformations related to mTOR dysregulations: challenges and perspectives. J Anat 2019; 235:521-542. [PMID: 30901081 DOI: 10.1111/joa.12956] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2019] [Indexed: 12/20/2022] Open
Abstract
In recent years the role of the mammalian target of rapamycin (mTOR) pathway has emerged as crucial for normal cortical development. Therefore, it is not surprising that aberrant activation of mTOR is associated with developmental malformations and epileptogenesis. A broad spectrum of malformations of cortical development, such as focal cortical dysplasia (FCD) and tuberous sclerosis complex (TSC), have been linked to either germline or somatic mutations in mTOR pathway-related genes, commonly summarised under the umbrella term 'mTORopathies'. However, there are still a number of unanswered questions regarding the involvement of mTOR in the pathophysiology of these abnormalities. Therefore, a monogenetic disease, such as TSC, can be more easily applied as a model to study the mechanisms of epileptogenesis and identify potential new targets of therapy. Developmental neuropathology and genetics demonstrate that FCD IIb and hemimegalencephaly are the same diseases. Constitutive activation of mTOR signalling represents a shared pathogenic mechanism in a group of developmental malformations that have histopathological and clinical features in common, such as epilepsy, autism and other comorbidities. We seek to understand the effect of mTOR dysregulation in a developing cortex with the propensity to generate seizures as well as the aftermath of the surrounding environment, including the white matter.
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Affiliation(s)
- A Mühlebner
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - A Bongaarts
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - H B Sarnat
- Departments of Paediatrics, Pathology (Neuropathology) and Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute (Owerko Centre), Calgary, AB, Canada
| | - T Scholl
- Department of Paediatric and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - E Aronica
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Amsterdam, The Netherlands
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Celli R, Santolini I, Van Luijtelaar G, Ngomba RT, Bruno V, Nicoletti F. Targeting metabotropic glutamate receptors in the treatment of epilepsy: rationale and current status. Expert Opin Ther Targets 2019; 23:341-351. [PMID: 30801204 DOI: 10.1080/14728222.2019.1586885] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Several drugs targeting the GABAergic system are used in the treatment of epilepsy, but only one drug targeting glutamate receptors is on the market. This is surprising because an imbalance between excitatory and inhibitory neurotransmission lies at the core of the pathophysiology of epilepsy. One possible explanation is that drug development has been directed towards the synthesis of molecules that inhibit the activity of ionotropic glutamate receptors. These receptors mediate fast excitatory synaptic transmission in the central nervous system (CNS) and their blockade may cause severe adverse effects such as sedation, cognitive impairment, and psychotomimetic effects. Metabotropic glutamate (mGlu) receptors are more promising drug targets because these receptors modulate synaptic transmission rather than mediate it. Areas covered: We review the current evidence that links mGlu receptor subtypes to the pathophysiology and experimental treatment of convulsive and absence seizures. Expert opinion: While mGlu5 receptor negative allosteric modulators have the potential to be protective against convulsive seizures and hyperactivity-induced neurodegeneration, drugs that enhance mGlu5 and mGlu7 receptor function may have beneficial effects in the treatment of absence epilepsy. Evidence related to the other mGlu receptor subtypes is more fragmentary; further investigations are required for an improved understanding of their role in the generation and propagation of seizures.
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Affiliation(s)
| | | | | | | | - Valeria Bruno
- a IRCCS NEUROMED , Pozzilli , Italy.,d Departments of Physiology and Pharmacology , University Sapienza , Rome , Italy
| | - Ferdinando Nicoletti
- a IRCCS NEUROMED , Pozzilli , Italy.,d Departments of Physiology and Pharmacology , University Sapienza , Rome , Italy
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Blauwblomme T, Dossi E, Pellegrino C, Goubert E, Iglesias BG, Sainte-Rose C, Rouach N, Nabbout R, Huberfeld G. Gamma-aminobutyric acidergic transmission underlies interictal epileptogenicity in pediatric focal cortical dysplasia. Ann Neurol 2019; 85:204-217. [PMID: 30597612 DOI: 10.1002/ana.25403] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Dysregulation of γ-aminobutyric acidergic (GABAergic) transmission has been reported in lesional acquired epilepsies (gliomas, hippocampal sclerosis). We investigated its involvement in a developmental disorder, human focal cortical dysplasia (FCD), focusing on chloride regulation driving GABAergic signals. METHODS In vitro recordings of 47 human cortical acute slices from 11 pediatric patients who received operations for FCD were performed on multielectrode arrays. GABAergic receptors and chloride regulators were pharmacologically modulated. Immunostaining for chloride cotransporter KCC2 and interneurons were performed on recorded slices to correlate electrophysiology and expression patterns. RESULTS FCD slices retain intrinsic epileptogenicity. Thirty-six of 47 slices displayed spontaneous interictal discharges, along with a pattern specific to the histological subtypes. Ictal discharges were induced in proepileptic conditions in 6 of 8 slices in the areas generating spontaneous interictal discharges, with a transition to seizure involving the emergence of preictal discharges. Interictal discharges were sustained by GABAergic signaling, as a GABAA receptor blocker stopped them in 2 of 3 slices. Blockade of NKCC1 Cl- cotransporters further controlled interictal discharges in 9 of 12 cases, revealing a Cl- dysregulation affecting actions of GABA. Immunohistochemistry highlighted decreased expression and changes in KCC2 subcellular localization and a decrease in the number of GAD67-positive interneurons in regions generating interictal discharges. INTERPRETATION Altered chloride cotransporter expression and changes in interneuron density in FCD may lead to paradoxical depolarization of pyramidal cells. Spontaneous interictal discharges are consequently mediated by GABAergic signals, and targeting chloride regulation in neurons may be considered for the development of new antiepileptic drugs. Ann Neurol 2019; 1-14 ANN NEUROL 2019;85:204-217.
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Affiliation(s)
- Thomas Blauwblomme
- APHP, Department of Pediatric Neurosurgery, Hospital Necker, Paris, France.,Université René Descartes. PRES Sorbonne Paris Cité, Paris, France.,INSERM U1129, Infantile Epilepsies and Brain Plasticity, Paris Descartes University, PRES Sorbonne Paris Cité, Paris, France
| | - Elena Dossi
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | | | | | - Beatriz Gal Iglesias
- Facultad de Ciencias Biomédicas y de la Salud, Universidad Europea, Madrid, Spain
| | - Christian Sainte-Rose
- APHP, Department of Pediatric Neurosurgery, Hospital Necker, Paris, France.,Université René Descartes. PRES Sorbonne Paris Cité, Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Rima Nabbout
- Université René Descartes. PRES Sorbonne Paris Cité, Paris, France.,APHP, Department of Neuropediatrics, Hospital Necker, Paris, France
| | - Gilles Huberfeld
- INSERM U1129, Infantile Epilepsies and Brain Plasticity, Paris Descartes University, PRES Sorbonne Paris Cité, Paris, France.,Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.,Sorbonne University, AP-HP, Department of Neurophysiology, La Pitié-Salpêtrière Hospital, Paris, France
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11
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Conditional Knock-out of mGluR5 from Astrocytes during Epilepsy Development Impairs High-Frequency Glutamate Uptake. J Neurosci 2018; 39:727-742. [PMID: 30504280 DOI: 10.1523/jneurosci.1148-18.2018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 11/11/2018] [Accepted: 11/18/2018] [Indexed: 11/21/2022] Open
Abstract
Astrocyte expression of metabotropic glutamate receptor 5 (mGluR5) is consistently observed in resected tissue from patients with epilepsy and is equally prevalent in animal models of epilepsy. However, little is known about the functional signaling properties or downstream consequences of astrocyte mGluR5 activation during epilepsy development. In the rodent brain, astrocyte mGluR5 expression is developmentally regulated and confined in expression/function to the first weeks of life, with similar observations made in human control tissue. Herein, we demonstrate that mGluR5 expression and function dramatically increase in a mouse model of temporal lobe epilepsy. Interestingly, in both male and female mice, mGluR5 function persists in the astrocyte throughout the process of epileptogenesis following status epilepticus. However, mGluR5 expression and function are transient in animals that do not develop epilepsy over an equivalent time period, suggesting that patterns of mGluR5 expression may signify continuing epilepsy development or its resolution. We demonstrate that, during epileptogenesis, astrocytes reacquire mGluR5-dependent calcium transients following agonist application or synaptic glutamate release, a feature of astrocyte-neuron communication absent since early development. Finally, we find that the selective and conditional knock-out of mGluR5 signaling from astrocytes during epilepsy development slows the rate of glutamate clearance through astrocyte glutamate transporters under high-frequency stimulation conditions, a feature that suggests astrocyte mGluR5 expression during epileptogenesis may recapitulate earlier developmental roles in regulating glutamate transporter function.SIGNIFICANCE STATEMENT In development, astrocyte mGluR5 signaling plays a critical role in regulating structural and functional interactions between astrocytes and neurons at the tripartite synapse. Notably, mGluR5 signaling is a positive regulator of astrocyte glutamate transporter expression and function, an essential component of excitatory signaling regulation in hippocampus. After early development, astrocyte mGluR5 expression is downregulated, but reemerges in animal models of temporal lobe epilepsy (TLE) development and patient epilepsy samples. We explored the hypothesis that astrocyte mGluR5 reemergence recapitulates earlier developmental roles during TLE acquisition. Our work demonstrates that astrocytes with mGluR5 signaling during TLE development perform faster glutamate uptake in hippocampus, revealing a previously unexplored role for astrocyte mGluR5 signaling in hypersynchronous pathology.
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12
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Spampinato SF, Copani A, Nicoletti F, Sortino MA, Caraci F. Metabotropic Glutamate Receptors in Glial Cells: A New Potential Target for Neuroprotection? Front Mol Neurosci 2018; 11:414. [PMID: 30483053 PMCID: PMC6243036 DOI: 10.3389/fnmol.2018.00414] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 10/25/2018] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative disorders are characterized by excitotoxicity and neuroinflammation that finally lead to slow neuronal degeneration and death. Although neurons are the principal target, glial cells are important players as they contribute by either exacerbating or dampening the events that lead to neuroinflammation and neuronal damage. A dysfunction of the glutamatergic system is a common event in the pathophysiology of these diseases. Metabotropic glutamate (mGlu) receptors belong to a large family of G protein-coupled receptors largely expressed in neurons as well as in glial cells. They often appear overexpressed in areas involved in neurodegeneration, where they can modulate glutamatergic transmission. Of note, mGlu receptor upregulation may involve microglia or, even more frequently, astrocytes, where their activation causes release of factors potentially able to influence neuronal death. The expression of mGlu receptors has been also reported on oligodendrocytes, a glial cell type specifically involved in the development of multiple sclerosis. Here we will provide a general overview on the possible involvement of mGlu receptors expressed on glial cells in the pathogenesis of different neurodegenerative disorders and the potential use of subtype-selective mGlu receptor ligands as candidate drugs for the treatment of neurodegenerative disorders. Negative allosteric modulators (NAM) of mGlu5 receptors might represent a relevant pharmacological tool to develop new neuroprotective strategies in these diseases. Recent evidence suggests that targeting astrocytes and microglia with positive allosteric modulators (PAM) of mGlu3 receptor or oligodendrocytes with mGlu4 PAMS might represent novel pharmacological approaches for the treatment of neurodegenerative disorders.
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Affiliation(s)
| | - Agata Copani
- Department of Drug Sciences, University of Catania, Catania, Italy.,Institute of Biostructure and Bioimaging, National Research Council, Catania, Italy
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Neuromed, Istituto di Ricovero e Cura a Carattere Scientifico, Pozzilli, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Filippo Caraci
- Department of Drug Sciences, University of Catania, Catania, Italy.,Oasi Research Institute, Istituto di Ricovero e Cura a Carattere Scientifico, Troina, Italy
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13
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Challenges in managing epilepsy associated with focal cortical dysplasia in children. Epilepsy Res 2018; 145:1-17. [DOI: 10.1016/j.eplepsyres.2018.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 04/30/2018] [Accepted: 05/12/2018] [Indexed: 12/15/2022]
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14
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Battaglia G, Bruno V. Metabotropic glutamate receptor involvement in the pathophysiology of amyotrophic lateral sclerosis: new potential drug targets for therapeutic applications. Curr Opin Pharmacol 2018. [DOI: 10.1016/j.coph.2018.02.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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15
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DuBois JM, Rousset OG, Guiot MC, Hall JA, Reader AJ, Soucy JP, Rosa-Neto P, Kobayashi E. Metabotropic Glutamate Receptor Type 5 (mGluR5) Cortical Abnormalities in Focal Cortical Dysplasia Identified In Vivo With [11C]ABP688 Positron-Emission Tomography (PET) Imaging. Cereb Cortex 2018; 26:4170-4179. [PMID: 27578494 PMCID: PMC5066831 DOI: 10.1093/cercor/bhw249] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 07/19/2016] [Indexed: 01/22/2023] Open
Abstract
Metabotropic glutamate receptor type 5 (mGluR5) abnormalities have been described in tissue resected from epilepsy patients with focal cortical dysplasia (FCD). To determine if these abnormalities could be identified in vivo, we investigated mGluR5 availability in 10 patients with focal epilepsy and an MRI diagnosis of FCD using positron-emission tomography (PET) and the radioligand [11C]ABP688. Partial volume corrected [11C]ABP688 binding potentials (BPND) were computed using the cerebellum as a reference region. Each patient was compared to homotopic cortical regions in 33 healthy controls using region-of-interest (ROI) and vertex-wise analyses. Reduced [11C]ABP688 BPND in the FCD was seen in 7/10 patients with combined ROI and vertex-wise analyses. Reduced FCD BPND was found in 4/5 operated patients (mean follow-up: 63 months; Engel I), of whom surgical specimens revealed FCD type IIb or IIa, with most balloon cells showing negative or weak mGluR5 immunoreactivity as compared to their respective neuropil and normal neurons at the border of resections. [11C]ABP688 PET shows for the first time in vivo evidence of reduced mGluR5 availability in FCD, indicating focal glutamatergic alterations in malformations of cortical development, which cannot be otherwise clearly demonstrated through resected tissue analyses.
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Affiliation(s)
- Jonathan M DuBois
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
| | - Olivier G Rousset
- Division of Nuclear Medicine and Molecular Imaging, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Marie-Christine Guiot
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.,Department of Pathology, McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Jeffery A Hall
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
| | - Andrew J Reader
- PET Unit, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4.,Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK
| | - Jean-Paul Soucy
- PET Unit, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4.,Bio-Imaging Group, PERFORM Centre, Concordia University, Montreal, Quebec, Canada H4B 1R6
| | - Pedro Rosa-Neto
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.,PET Unit, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4.,Translational Neuroimaging Laboratory, McGill Center for Studies in Aging, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada H4H 1R3
| | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
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16
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Qian F, Tang FR. Metabotropic Glutamate Receptors and Interacting Proteins in Epileptogenesis. Curr Neuropharmacol 2017; 14:551-62. [PMID: 27030135 PMCID: PMC4983745 DOI: 10.2174/1570159x14666160331142228] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 12/30/2015] [Accepted: 03/13/2016] [Indexed: 02/07/2023] Open
Abstract
Neurotransmitter and receptor systems are involved in different neurological and neuropsychological disorders such as Parkinson's disease, depression, Alzheimer’s disease and epilepsy. Recent advances in studies of signal transduction pathways or interacting proteins of neurotransmitter receptor systems suggest that different receptor systems may share the common signal transduction pathways or interacting proteins which may be better therapeutic targets for development of drugs to effectively control brain diseases. In this paper, we reviewed metabotropic glutamate receptors (mGluRs) and their related signal transduction pathways or interacting proteins in status epilepticus and temporal lobe epilepsy, and proposed some novel therapeutical drug targets for controlling epilepsy and epileptogenesis.
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Affiliation(s)
| | - Feng-Ru Tang
- Radiobiology Research Laboratory, Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore.
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17
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Stokum JA, Gerzanich V, Simard JM. Molecular pathophysiology of cerebral edema. J Cereb Blood Flow Metab 2016; 36:513-38. [PMID: 26661240 PMCID: PMC4776312 DOI: 10.1177/0271678x15617172] [Citation(s) in RCA: 357] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 12/25/2022]
Abstract
Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema.
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Affiliation(s)
- Jesse A Stokum
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA Department of Pathology, University of Maryland School of Medicine, Baltimore, USA Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
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18
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Metabotropic glutamate receptor 5 – a promising target in drug development and neuroimaging. Eur J Nucl Med Mol Imaging 2016; 43:1151-70. [DOI: 10.1007/s00259-015-3301-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 12/22/2015] [Indexed: 10/22/2022]
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19
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Zang Z, Li S, Zhang W, Chen X, Zheng D, Shu H, Guo W, Zhao B, Shen K, Wei Y, Zheng X, Liu S, Yang H. Expression Patterns of TRPC1 in Cortical Lesions from Patients with Focal Cortical Dysplasia. J Mol Neurosci 2015; 57:265-72. [PMID: 26280213 DOI: 10.1007/s12031-015-0615-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 06/30/2015] [Indexed: 02/05/2023]
Abstract
Focal cortical dysplasia (FCD) is known as a common cause of chronic refractory epilepsy, but the underlying mechanisms of the factors that lead to FCD-related epilepsy are unclear. Previous studies have shown that canonical transient receptor potential channels (TRPCs) might be involved in the process of epileptogenesis. Canonical transient receptor potential channel 1 (TRPC1), which is ubiquitously expressed in the brain, has been shown to be involved in epileptiform bust firing in knockout mice. In this study, we examined the expression of TRPC1 in FCD type Ia (FCDIa), FCD type IIa (FCDIIa), and FCD type IIb (FCDIIb) surgical specimens from patients and age-matched autopsy control samples. Real-time quantitative PCR and western blotting indicated that TRPC1 mRNA and protein levels were increased in FCDIa, FCDIIa, and FCDIIb samples compared to control samples. Immunohistochemistry results revealed that TRPC1 was mainly distributed in microcolumns, dysmorphic neurons, and balloon cells. Further double immunofluorescent staining showed that TRPC1 was co-localized with glutamatergic and GABAergic markers. Taken together, our results demonstrate that the overexpression and specific cellular location of TRPC1 might be related to the epileptogenesis of FCD.
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Affiliation(s)
- Zhenle Zang
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - Song Li
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - Wei Zhang
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - Xin Chen
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - Dahai Zheng
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - Haifeng Shu
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China.,Department of Neurosurgery, Chengdu Military General Hospital of PLA, Chengdu, Sichuan, 610083, China
| | - Wei Guo
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - Bangyun Zhao
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - Kaifeng Shen
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - YuJia Wei
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - Xin Zheng
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | - Shiyong Liu
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China.
| | - Hui Yang
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing, 400037, China.
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20
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Prabowo AS, van Scheppingen J, Iyer AM, Anink JJ, Spliet WGM, van Rijen PC, Schouten-van Meeteren AYN, Aronica E. Differential expression and clinical significance of three inflammation-related microRNAs in gangliogliomas. J Neuroinflammation 2015; 12:97. [PMID: 25986346 PMCID: PMC4446114 DOI: 10.1186/s12974-015-0315-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 04/30/2015] [Indexed: 01/18/2023] Open
Abstract
PURPOSE miR21, miR146, and miR155 represent a trio of microRNAs which has been shown to play a key role in the regulation of immune and inflammatory responses. In the present study, we investigated the differential expression and clinical significance of these three miRNAs in glioneuronal tumors (gangliogliomas, GGs) which are characterized by prominent activation of the innate immune response. METHODS The expression levels of miR21, miR146, and miR155 were evaluated using Taqman PCR in 34 GGs, including 15 cases with sufficient amount of perilesional cortex. Their expression was correlated with the tumor features and the clinical history of epilepsy. In addition, in situ hybridization was used to evaluate their cellular distribution in both tumor and peritumoral cortex. RESULTS Increased expression of miR146a was observed in both tumor and peritumoral cortex compared to control samples. miR146a was detected in both neuronal and astroglial cells. Tumor and peritumoral miR146a expression was negatively correlated with frequency of seizures and the density of activated microglial cells. Neuronal and astroglial expression was observed for both miR21 and miR155 with increased expression of miR21 within the tumor and miR155 in the peritumoral region. Negative correlations were observed between the miRNA levels and the expression of putative targets within the astroglial component of the tumor. CONCLUSION We report a differential regulation of three miRNAs, known to be related to inflammation, in both tumor and peritumoral cortex of patients with GG. Moreover, our findings suggest a functional relationship between miR146a expression and epilepsy, either directly in epileptogenesis or as modulation of seizure activity.
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Affiliation(s)
- A S Prabowo
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | - J van Scheppingen
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | - A M Iyer
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | - J J Anink
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | - W G M Spliet
- Department of Pathology, Rudolf Magnus Institute for Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - P C van Rijen
- Department of Neurosurgery, Rudolf Magnus Institute for Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - A Y N Schouten-van Meeteren
- Department of Pediatric Oncology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | - E Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. .,SEIN - Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands. .,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands.
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21
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Aronica E, Baas F, Iyer A, ten Asbroek AL, Morello G, Cavallaro S. Molecular classification of amyotrophic lateral sclerosis by unsupervised clustering of gene expression in motor cortex. Neurobiol Dis 2015; 74:359-76. [DOI: 10.1016/j.nbd.2014.12.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 11/12/2014] [Accepted: 12/02/2014] [Indexed: 12/15/2022] Open
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22
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Prabowo AS, Iyer AM, Veersema TJ, Anink JJ, Schouten-van Meeteren AYN, Spliet WGM, van Rijen PC, Ferrier CH, Thom M, Aronica E. Expression of neurodegenerative disease-related proteins and caspase-3 in glioneuronal tumours. Neuropathol Appl Neurobiol 2015; 41:e1-e15. [DOI: 10.1111/nan.12143] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 04/04/2014] [Indexed: 02/06/2023]
Affiliation(s)
- A. S. Prabowo
- Department of (Neuro)Pathology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - A. M. Iyer
- Department of (Neuro)Pathology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - T. J. Veersema
- Department of Neurosurgery; University Medical Center Utrecht; Utrecht The Netherlands
- Department of Neurology; University Medical Center Utrecht; Utrecht The Netherlands
| | - J. J. Anink
- Department of (Neuro)Pathology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - A. Y. N. Schouten-van Meeteren
- Department of Pediatric Oncology; Emma Children's Hospital; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - W. G. M. Spliet
- Rudolf Magnus Institute for Neuroscience and Pathology; University Medical Center Utrecht; Utrecht The Netherlands
| | - P. C. van Rijen
- Department of Neurosurgery; University Medical Center Utrecht; Utrecht The Netherlands
| | - C. H. Ferrier
- Department of Neurology; University Medical Center Utrecht; Utrecht The Netherlands
- Department of Clinical Neurophysiology; University Medical Center Utrecht; Utrecht The Netherlands
| | - M. Thom
- Neuropathology Department; University College London Institute of Neurology; London UK
| | - E. Aronica
- Department of (Neuro)Pathology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
- Swammerdam Institute for Life Sciences; Center for Neuroscience; University of Amsterdam; Amsterdam The Netherlands
- SEIN - Stichting Epilepsie Instellingen Nederland; Heemstede The Netherlands
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23
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Expression of astrocyte-related receptors in cortical dysplasia with intractable epilepsy. J Neuropathol Exp Neurol 2014; 73:798-806. [PMID: 25003238 DOI: 10.1097/nen.0000000000000099] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Epilepsy is one of the major neurologic diseases, and astrocytes play important roles in epileptogenesis. To investigate possible roles of astrocyte-related receptors in patients with intractable epilepsy associated with focal cortical dysplasia (FCD) and other conditions, we examined resected epileptic foci from 31 patients, including 23 with FCD type I, IIa, or IIb, 5 with tuberous sclerosis complex, and 3 with low-grade astrocytoma. Control samples were from 21 autopsied brains of patients without epilepsy or neurologic deficits and 5 patients with pathologic gliosis without epilepsy. Immunohistochemical and immunoblot analyses with antibodies against purinergic receptor subtypes P2RY1, P2RY2, P2RY4, potassium channels Kv4.2 and Kir4.1, and metabotropic receptor subtypes mGluR1 and mGluR5 were performed. Anti-glial fibrillary acidic protein, anti-NeuN, and anti-CD68 immunostaining was used to identify astrocytes, neurons, and microglia, respectively. Most glial fibrillary acidic protein-immunopositive astrocyte cells in the brain samples from patients with epilepsy were P2RY1-, P2RY2-, P2RY4-, Kv4.2-, Kir4.1-, mGluR1-, and mGluR5-positive, whereas samples from controls and pathologic gliosis showed lower expression levels of these astrocyte-related receptors. Our findings suggest that, although these receptors are necessary for astrocyte transmission, formation of the neuron-glia network, and other physiologic functions, overexpression in the brains of patients with intractable epilepsy may be associated with activation of intracellular and glio-neuronal signaling pathways that contribute to epileptogenesis.
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24
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Sephton SM, Herde AM, Mu L, Keller C, Rüdisühli S, Auberson Y, Schibli R, Krämer SD, Ametamey SM. Preclinical evaluation and test-retest studies of [(18)F]PSS232, a novel radioligand for targeting metabotropic glutamate receptor 5 (mGlu5). Eur J Nucl Med Mol Imaging 2014; 42:128-37. [PMID: 25139517 DOI: 10.1007/s00259-014-2883-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/28/2014] [Indexed: 12/21/2022]
Abstract
PURPOSE A novel, (18)F-labelled metabotropic glutamate receptor subtype 5 (mGlu5) derivative of [(11)C]ABP688 ([(11)C]1), [(18)F]PSS232 ([(18)F] ]5), was evaluated in vitro and in vivo for its potential as a PET agent and was used in test-retest reliability studies METHODS The radiosynthesis of [(18)F]5 was accomplished via a one-step reaction using a mesylate precursor. In vitro stability was determined in PBS and plasma, and with liver microsomal enzymes. Metabolite studies were performed using rat brain extracts, blood and urine. In vitro autoradiography was performed on horizontal slices of rat brain using 1 and 8, antagonists for mGlu5 and mGlu1, respectively. Small-animal PET, biodistribution, and test-retest studies were performed in Wistar rats. In vivo, dose-dependent displacement studies were performed using 6 and blocking studies with 7. RESULTS [(18)F]5 was obtained in decay-corrected maximal radiochemical yield of 37 % with a specific activity of 80 - 400 GBq/μmol. Treatment with rat and human microsomal enzymes in vitro for 60 min resulted in 20 % and 4 % of hydrophilic radiometabolites, respectively. No hydrophilic decomposition products or radiometabolites were found in PBS or plasma. In vitro autoradiography on rat brain slices showed a heterogeneous distribution consistent with the known distribution of mGlu5 with high binding to hippocampal and cortical regions, and negligible radioactivity in the cerebellum. Similar distribution of radioactivity was found in PET images. Under displacement conditions with 6, reduced [(18)F]5 binding was found in all brain regions except the cerebellum. 7 reduced binding in the striatum by 84 % on average. Test-retest studies were reproducible with a variability ranging from 6.8 % to 8.2 %. An extended single-dose toxicity study in Wistar rats showed no compound-related adverse effects. CONCLUSION The new mGlu5 radiotracer, [(18)F]5, showed specific and selective in vitro and in vivo properties and is a promising radioligand for PET imaging of mGlu5 in humans.
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Affiliation(s)
- Selena Milicevic Sephton
- Center for Radiopharmaceutical Sciences of ETH, PSI and USZ, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
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25
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Correlation between clinical and histologic findings in the human neonatal hippocampus after perinatal asphyxia. J Neuropathol Exp Neurol 2014; 73:324-34. [PMID: 24607964 DOI: 10.1097/nen.0000000000000056] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Hypoxic ischemic encephalopathy after perinatal asphyxia is a major cause of mortality and morbidity in infants. Here, we evaluated pathologic changes in the hippocampi of a cohort of 16 deceased full-term asphyxiated infants who died from January 2000 to January 2009. Histochemical and immunocytochemical results for glial and neuronal cells were compared between cases with or without seizures and to adult and sudden infant death syndrome cases (n = 3 each). All asphyxiated infants displayed neuronal cell damage and reactive glial changes. Strong aquaporin-4 immunoreactivity was seen on astroglial cells within hippocampi in 50% of cases. In patients with seizures, the expression of metabotropic glutamate receptors was increased in glial cells. Cases with seizures displayed increased microglial activation and greater expression of the inflammatory markers interleukin 1β and complement 1q compared with those in cases without seizures. All cases with seizures displayed alterations in the blood-brain barrier, as assessed by immunohistochemistry for albumin. These findings confirm the complex cascade of cellular and molecular changes occurring in the human neonatal hippocampus after perinatal asphyxia. These changes may contribute to seizure development leading to secondary brain damage. These data may aid in the development of therapeutic targets for neonatal seizures.
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26
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Aronica E, Crino PB. Epilepsy related to developmental tumors and malformations of cortical development. Neurotherapeutics 2014; 11:251-68. [PMID: 24481729 PMCID: PMC3996119 DOI: 10.1007/s13311-013-0251-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Structural abnormalities of the brain are increasingly recognized in patients with neurodevelopmental delay and intractable focal epilepsies. The access to clinically well-characterized neurosurgical material has provided a unique opportunity to better define the neuropathological, neurochemical, and molecular features of epilepsy-associated focal developmental lesions. These studies help to further understand the epileptogenic mechanisms of these lesions. Neuropathological evaluation of surgical specimens from patients with epilepsy-associated developmental lesions reveals two major pathologies: focal cortical dysplasia and low-grade developmental tumors (glioneuronal tumors). In the last few years there have been major advances in the recognition of a wide spectrum of developmental lesions associated with a intractable epilepsy, including cortical tubers in patients with tuberous sclerosis complex and hemimegalencephaly. As an increasing number of entities are identified, the development of a unified and comprehensive classification represents a great challenge and requires continuous updates. The present article reviews current knowledge of molecular pathogenesis and the pathophysiological mechanisms of epileptogenesis in this group of developmental disorders. Both emerging neuropathological and basic science evidence will be analyzed, highlighting the involvement of different, but often converging, pathogenetic and epileptogenic mechanisms, which may create the basis for new therapeutic strategies in these disorders.
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Affiliation(s)
- Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands,
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In vivo imaging of mGluR5 changes during epileptogenesis using [11C]ABP688 PET in pilocarpine-induced epilepsy rat model. PLoS One 2014; 9:e92765. [PMID: 24663806 PMCID: PMC3963947 DOI: 10.1371/journal.pone.0092765] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 02/26/2014] [Indexed: 11/28/2022] Open
Abstract
Introduction Metabotropic glutamate receptor 5 (mGluR5) that regulates glutamatergic neurotransmission contributes to pathophysiology of epilepsy. In this study, we monitored the changes of mGluR5 in vivo using [11C]ABP688 PET during the epileptogenesis in a pilocarpine-induced epilepsy rat model. Methods In vivo mGluR5 images were acquired using [11C]ABP688 microPET/CT in pilocarpine-induced chronic epilepsy rat models and controls. We also acquired microPET/CT at acute, subacute as well as chronic periods after status epilepticus. Non-displaceable binding potential (BPND) of [11C]ABP688 was calculated using simplified reference tissue model in a voxel-based manner. mGluR5 BPND of the rat brains of epilepsy models and controls were compared. Results Status epilepticus developed after pilocarpine administration and was followed by recurrent spontaneous seizures for more than 3 weeks. In chronic epilepsy rat model, BPND in hippocampus and amygdala was reduced on a voxel-based analysis. Temporal changes of mGluR5 BPND was also found. In acute period after status epilepticus, mGluR5 BPND was reduced in the whole brain. BPND of caudate-putamen was restored in subacute period, while BPND of the rest of the brain was still lower. In chronic period, global BPND was normalized except in hippocampus and amygdala. Conclusions In vivo imaging of mGluR5 using [11C]ABP688 microPET/CT could successfully reveal the regional changes of mGluR5 binding potential of the rat brain in a pilocarpine-induced epilepsy model. The temporal and spatial changes in mGluR5 availability suggest [11C]ABP688 PET imaging in epilepsy provide abnormal glutamatergic network during epileptogenesis.
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Gorter JA, Iyer A, White I, Colzi A, van Vliet EA, Sisodiya S, Aronica E. Hippocampal subregion-specific microRNA expression during epileptogenesis in experimental temporal lobe epilepsy. Neurobiol Dis 2014; 62:508-20. [DOI: 10.1016/j.nbd.2013.10.026] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 10/11/2013] [Accepted: 10/24/2013] [Indexed: 11/25/2022] Open
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Ranno E, D'Antoni S, Spatuzza M, Berretta A, Laureanti F, Bonaccorso CM, Pellitteri R, Longone P, Spalloni A, Iyer AM, Aronica E, Catania MV. Endothelin-1 is over-expressed in amyotrophic lateral sclerosis and induces motor neuron cell death. Neurobiol Dis 2014; 65:160-71. [PMID: 24423643 DOI: 10.1016/j.nbd.2014.01.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 12/13/2013] [Accepted: 01/04/2014] [Indexed: 12/25/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by progressive loss of motor neurons (MNs) and astrogliosis. Recent evidence suggests that factors secreted by activated astrocytes might contribute to degeneration of MNs. We focused on endothelin-1 (ET-1), a peptide which is strongly up-regulated in reactive astrocytes under different pathological conditions. We show that ET-1 is abundantly expressed by reactive astrocytes in the spinal cord of the SOD1-G93A mouse model and sporadic ALS patients. To test if ET-1 might play a role in degeneration of MNs, we investigated its effect on MN survival in an in vitro model of mixed rat spinal cord cultures (MSCs) enriched of astrocytes exhibiting a reactive phenotype. ET-1 exerted a toxic effect on MNs in a time- and concentration-dependent manner, with an exposure to 100-200nM ET-1 for 48h resulting in 40-50% MN cell death. Importantly, ET-1 did not induce MN degeneration when administered on cultures treated with AraC (5μM) or grown in a serum-free medium that did not favor astrocyte proliferation and reactivity. We found that both ETA and ETB receptors are enriched in astrocytes in MSCs. The ET-1 toxic effect was mimicked by ET-3 (100nM) and sarafotoxin S6c (10nM), two selective agonists of endothelin-B receptors, and was not additive with that of ET-3 suggesting the involvement of ETB receptors. Surprisingly, however, the ET-1 effect persisted in the presence of the ETB receptor antagonist BQ-788 (200nM-2μM) and was slightly reversed by the ETA receptor antagonist BQ-123 (2μM), suggesting an atypical pharmacological profile of the astrocytic receptors responsible for ET-1 toxicity. The ET-1 effect was not undone by the ionotropic glutamate receptor AMPA antagonist GYKI 52466 (20μM), indicating that it is not caused by an increased glutamate release. Conversely, a 48-hour ET-1 treatment increased MN cell death induced by acute exposure to AMPA (50μM), which is indicative of two distinct pathways leading to neuronal death. Altogether these results indicate that ET-1 exerts a toxic effect on cultured MNs through mechanisms mediated by reactive astrocytes and suggest that ET-1 may contribute to MN degeneration in ALS. Thus, a treatment aimed at lowering ET-1 levels or antagonizing its effect might be envisaged as a potential therapeutic strategy to slow down MN degeneration in this devastating disease.
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Affiliation(s)
- Eugenia Ranno
- Institute of Neurological Sciences, National Research Council (ISN-CNR), Catania, Italy; PhD Program in Neurobiology, University of Catania, Catania, Italy
| | - Simona D'Antoni
- Institute of Neurological Sciences, National Research Council (ISN-CNR), Catania, Italy
| | - Michela Spatuzza
- Institute of Neurological Sciences, National Research Council (ISN-CNR), Catania, Italy
| | - Antonio Berretta
- Institute of Neurological Sciences, National Research Council (ISN-CNR), Catania, Italy
| | - Floriana Laureanti
- Department of Biomedical Sciences, Section of Physiology, University of Catania, Catania, Italy
| | | | - Rosalia Pellitteri
- Institute of Neurological Sciences, National Research Council (ISN-CNR), Catania, Italy
| | - Patrizia Longone
- Molecular Neurobiology Unit, Experimental Neurology, Fondazione Santa Lucia, Rome, Italy
| | - Alida Spalloni
- Molecular Neurobiology Unit, Experimental Neurology, Fondazione Santa Lucia, Rome, Italy
| | - Anand M Iyer
- Department of (Neuro) Pathology, Academic Medical Center, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro) Pathology, Academic Medical Center, Amsterdam, The Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands
| | - Maria Vincenza Catania
- Institute of Neurological Sciences, National Research Council (ISN-CNR), Catania, Italy; IRCCS Oasi Maria SS, Troina (EN), Italy.
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Davila D, Thibault K, Fiacco TA, Agulhon C. Recent molecular approaches to understanding astrocyte function in vivo. Front Cell Neurosci 2013; 7:272. [PMID: 24399932 PMCID: PMC3871966 DOI: 10.3389/fncel.2013.00272] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/06/2013] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are a predominant glial cell type in the nervous systems, and are becoming recognized as important mediators of normal brain function as well as neurodevelopmental, neurological, and neurodegenerative brain diseases. Although numerous potential mechanisms have been proposed to explain the role of astrocytes in the normal and diseased brain, research into the physiological relevance of these mechanisms in vivo is just beginning. In this review, we will summarize recent developments in innovative and powerful molecular approaches, including knockout mouse models, transgenic mouse models, and astrocyte-targeted gene transfer/expression, which have led to advances in understanding astrocyte biology in vivo that were heretofore inaccessible to experimentation. We will examine the recently improved understanding of the roles of astrocytes – with an emphasis on astrocyte signaling – in the context of both the healthy and diseased brain, discuss areas where the role of astrocytes remains debated, and suggest new research directions.
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Affiliation(s)
- David Davila
- Glia-Glia and Glia-Neuron Interactions Group, National Center for Scientific Research, UFR Biomedicale, Paris Descartes University Paris, France
| | - Karine Thibault
- Glia-Glia and Glia-Neuron Interactions Group, National Center for Scientific Research, UFR Biomedicale, Paris Descartes University Paris, France
| | - Todd A Fiacco
- Department of Cell Biology and Neuroscience, and Center for Glial-Neuronal Interactions and Program in Cellular, Molecular and Developmental Biology, University of California at Riverside Riverside, CA, USA
| | - Cendra Agulhon
- Glia-Glia and Glia-Neuron Interactions Group, National Center for Scientific Research, UFR Biomedicale, Paris Descartes University Paris, France
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Hubbard JA, Hsu MS, Fiacco TA, Binder DK. Glial cell changes in epilepsy: Overview of the clinical problem and therapeutic opportunities. Neurochem Int 2013; 63:638-51. [DOI: 10.1016/j.neuint.2013.01.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/14/2013] [Accepted: 01/18/2013] [Indexed: 12/20/2022]
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Caulder EH, Riegle MA, Godwin DW. Activation of group 2 metabotropic glutamate receptors reduces behavioral and electrographic correlates of pilocarpine induced status epilepticus. Epilepsy Res 2013; 108:171-81. [PMID: 24305700 DOI: 10.1016/j.eplepsyres.2013.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 09/25/2013] [Accepted: 10/18/2013] [Indexed: 12/11/2022]
Abstract
Novel treatments for epilepsy are necessary because many epilepsy patients are resistant to medication. Metabotropic glutamate receptors (mGluRs), specifically mGluR 2 and 3, may serve as antiepileptic drug targets because of their role in controlling synaptic release. In this study, we administered a Group 2 mGluR agonist, LY379268, one of two mGluR2-specific positive allosteric modulators, BINA or CBiPES, or a cocktail of both BINA and LY379268 in a series of experiments using the pilocarpine model of SE. In one study, groups received treatments 15 min prior to pilocarpine, while in a second study groups received treatments after SE had been initiated to determine whether the drugs could reduce development and progression of SE. We measured bouts of stage 5 seizures, latency to the first seizure, and the maximum Racine score to characterize the seizure severity. We analyzed mouse EEG with implanted electrodes using a power analysis. We found that pretreatment and posttreatment with LY379268 was effective at reducing both behavioral correlates and power in EEG bandwidths associated with seizure, while CBiPES was less effective and BINA was ineffective. These data generally support continued development of mGluR2 pharmacology for novel antiepileptic drugs, though further study with additional drugs and concentrations will be necessary.
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Affiliation(s)
- Erin H Caulder
- Wake Forest University Graduate School of Arts and Sciences, Department of Neurobiology and Anatomy, 1 Medical Center Boulevard, Winston Salem, NC 27157, USA.
| | - Melissa A Riegle
- Wake Forest University Graduate School of Arts and Sciences, Department of Neurobiology and Anatomy, 1 Medical Center Boulevard, Winston Salem, NC 27157, USA; Wake Forest University Graduate School of Arts and Sciences, Neuroscience Program, 1 Medical Center Boulevard, Winston Salem, NC 27157, USA.
| | - Dwayne W Godwin
- Wake Forest University Graduate School of Arts and Sciences, Department of Neurobiology and Anatomy, 1 Medical Center Boulevard, Winston Salem, NC 27157, USA; Wake Forest University Graduate School of Arts and Sciences, Neuroscience Program, 1 Medical Center Boulevard, Winston Salem, NC 27157, USA.
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Kawamura K, Yamasaki T, Kumata K, Furutsuka K, Takei M, Wakizaka H, Fujinaga M, Kariya K, Yui J, Hatori A, Xie L, Shimoda Y, Hashimoto H, Hayashi K, Zhang MR. Binding potential of (E)-[¹¹C]ABP688 to metabotropic glutamate receptor subtype 5 is decreased by the inclusion of its ¹¹C-labelled Z-isomer. Nucl Med Biol 2013; 41:17-23. [PMID: 24183615 DOI: 10.1016/j.nucmedbio.2013.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/24/2013] [Accepted: 09/28/2013] [Indexed: 01/15/2023]
Abstract
INTRODUCTION [(11)C]ABP688 is a promising positron emission tomography (PET) ligand for imaging of metabotropic glutamate receptor subtype 5 (mGlu5 receptor). Of the two geometric isomers of ABP688, (E)-ABP688 has a greater affinity towards mGlu5 receptors than (Z)-ABP688. Therefore, a high ratio of E-isomer is required when using [(11)C]ABP688 as a PET probe for imaging and quantification of mGlu5 receptors. The aim of this study was to evaluate the effect (Z)-[(11)C]ABP688 on the synthesis of [(11)C]ABP688 to be used for binding (E)-[(11)C]ABP688 in the brain. METHODS We synthesized and separated (E)- and (Z)-[(11)C]ABP688 by purification using an improved preparative high-performance liquid chromatography (HPLC) method equipped with a COSMOSIL Cholester column. We performed an in vitro binding assay in rat brain homogenates and PET studies of the rat brains using (E)- and (Z)-[(11)C]ABP688. RESULTS (E)- and (Z)-[(11)C]ABP688 were successfully obtained with suitable radioactivity for application. In the in vitro assay, the Kd value of (E)-[(11)C]ABP688 (5.7 nmol/L) was higher than that of (Z)-[(11)C]ABP688 (140 nmol/L). In the PET study of the rat brain, high radioactivity after injection of (E)-[(11)C]ABP688 was observed in regions rich in mGlu5 receptors such as the striatum and hippocampus. In contrast, after injection of (Z)-[(11)C]ABP688, radioactivity did not accumulate in the brain. Furthermore, BPND in the striatum and hippocampus was highly correlated (R(2) = 0.99) with the percentage of (E)-[(11)C]ABP688 of the total radioactivity of (E)- and (Z)-[(11)C]ABP688 in the injection. CONCLUSION We demonstrated that including (Z)-[(11)C]ABP688 in the [(11)C]ABP688 injection can decrease BPND in regions rich in mGlu5 receptors. Routine production of (E)-[(11)C]ABP688 will be helpful for imaging and quantification of mGlu5 receptors in clinical studies.
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Affiliation(s)
- Kazunori Kawamura
- Molecular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan.
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Prabowo AS, Iyer AM, Veersema TJ, Anink JJ, Schouten-van Meeteren AYN, Spliet WGM, van Rijen PC, Ferrier CH, Capper D, Thom M, Aronica E. BRAF V600E mutation is associated with mTOR signaling activation in glioneuronal tumors. Brain Pathol 2013; 24:52-66. [PMID: 23941441 DOI: 10.1111/bpa.12081] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 07/25/2013] [Indexed: 02/06/2023] Open
Abstract
BRAF V600E mutations have been recently reported in glioneuronal tumors (GNTs). To evaluate the expression of the BRAF V600E mutated protein and its association with activation of the mammalian target of rapamycin (mTOR) pathway, immunophenotype and clinical characteristics in GNTs, we investigated a cohort of 174 GNTs. The presence of BRAF V600E mutations was detected by direct DNA sequencing and BRAF V600E immunohistochemical detection. Expression of BRAF-mutated protein was detected in 38/93 (40.8%) gangliogliomas (GGs), 2/4 (50%) desmoplastic infantile gangliogliomas (DIGs) and 23/77 (29.8%) dysembryoplastic neuroepithelial tumors (DNTs) by immunohistochemistry. In both GGs and DNTs, the presence of BRAF V600E mutation was significantly associated with the expression of CD34, phosphorylated ribosomal S6 protein (pS6; marker of mTOR pathway activation) in dysplastic neurons and synaptophysin (P < 0.05). In GGs, the presence of lymphocytic cuffs was more frequent in BRAF-mutated cases (31 vs. 15.8%; P=0.001). The expression of both BRAF V600E and pS6 was associated with a worse postoperative seizure outcome in GNT (P < 0.001). Immunohistochemical detection of BRAF V600E-mutated protein may be valuable in the diagnostic evaluation of these glioneuronal lesions and the observed association with mTOR activation may aid in the development of targeted treatment involving specific pathogenic pathways.
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Affiliation(s)
- Avanita S Prabowo
- Department of (Neuro)Pathology, University of Amsterdam, Amsterdam, The Netherlands
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Seifert G, Steinhäuser C. Neuron–astrocyte signaling and epilepsy. Exp Neurol 2013; 244:4-10. [DOI: 10.1016/j.expneurol.2011.08.024] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 08/16/2011] [Accepted: 08/25/2011] [Indexed: 12/30/2022]
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Iyer A, Prabowo A, Anink J, Spliet WGM, van Rijen PC, Aronica E. Cell injury and premature neurodegeneration in focal malformations of cortical development. Brain Pathol 2013; 24:1-17. [PMID: 23586324 DOI: 10.1111/bpa.12060] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 03/26/2013] [Indexed: 12/17/2022] Open
Abstract
Several lines of evidence suggest that cell injury may occur in malformations of cortical development associated with epilepsy. Moreover, recent studies support the link between neurodevelopmental and neurodegenerative mechanisms. We evaluated a series of focal cortical dysplasia (FCD, n=26; type I and II) and tuberous sclerosis complex (TSC, n=6) cases. Sections were processed for terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick-end labeling (TUNEL) labeling and immunohistochemistry using markers for the evaluation of apoptosis signaling pathways and neurodegeneration-related proteins/pathways. In both FCD II and TSC specimens, we observed significant increases in both TUNEL-positive and caspase-3-positive cells compared with controls and FCD I. Expression of β-amyloid precursor protein was observed in neuronal soma and processes in FCD II and TSC. In these specimens, we also observed an abnormal expression of death receptor-6. Immunoreactivity for phosphorylated tau was only found in older patients with FCD II and TSC. In these cases, prominent nuclear/cytoplasmic p62 immunoreactivity was detected in both dysmorphic neurons and balloon/giant cells. Our data provide evidence of complex, but similar, mechanisms of cell injury in focal malformations of cortical development associated with mammalian target of rapamycin pathway hyperactivation, with prominent induction of apoptosis-signaling pathways and premature activation of mechanisms of neurodegeneration.
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Affiliation(s)
- Anand Iyer
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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Lim D, Iyer A, Ronco V, Grolla AA, Canonico PL, Aronica E, Genazzani AA. Amyloid beta deregulates astroglial mGluR5-mediated calcium signaling via calcineurin and Nf-kB. Glia 2013; 61:1134-45. [DOI: 10.1002/glia.22502] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/05/2013] [Indexed: 12/24/2022]
Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro,”; Novara; Italy
| | - Anand Iyer
- Department of (Neuro)Pathology; Academic Medical Center, University of Amsterdam; Amsterdam; The Netherlands
| | - Virginia Ronco
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro,”; Novara; Italy
| | - Ambra A. Grolla
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro,”; Novara; Italy
| | - Pier Luigi Canonico
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro,”; Novara; Italy
| | | | - Armando A. Genazzani
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro,”; Novara; Italy
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Paquet M, Ribeiro FM, Guadagno J, Esseltine JL, Ferguson SSG, Cregan SP. Role of metabotropic glutamate receptor 5 signaling and homer in oxygen glucose deprivation-mediated astrocyte apoptosis. Mol Brain 2013; 6:9. [PMID: 23406666 PMCID: PMC3598502 DOI: 10.1186/1756-6606-6-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Group I metabotropic glutamate receptors (mGluR) are coupled via Gαq/11 to the activation of phospholipase Cβ, which hydrolyzes membrane phospholipids to form inositol 1,4,5 trisphosphate and diacylglycerol. In addition to functioning as neurotransmitter receptors to modulate synaptic activity, pathological mGluR5 signaling has been implicated in a number of disease processes including Fragile X, amyotrophic lateral sclerosis, multiple sclerosis, Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy, and drug addiction. The expression of mGluR5 in astrocytes has been shown to be increased in several acute and chronic neurodegenerative conditions, but little is known about the functional relevance of mGluR5 up-regulation in astrocytes following injury. RESULTS In the current study, we investigated primary mouse cortical astrocyte cell death in response to oxygen glucose deprivation (OGD) and found that OGD induced both necrotic and apoptotic cell death of astrocytes. OGD resulted in an increase in astrocytic mGluR5 protein expression, inositol phosphate formation and extracellular regulated kinase (ERK1/2) phosphorylation, but only inositol phosphate formation was blocked with the mGluR5 selective antagonist MPEP. Cortical astrocytes derived from mGluR5 knockout mice exhibited resistance to OGD-stimulated apoptosis, but a lack of mGluR5 expression did not confer protection against necrotic cell death. The antagonism of the inositol 1,4,5 trisphosphate receptor also reduced apoptotic cell death in wild-type astrocytes, but did not provide any additional protection to astrocytes derived from mGluR5 null mice. Moreover, the disruption of Homer protein interactions with mGluR5 also reduced astrocyte apoptosis. CONCLUSION Taken together these observations indicated that mGluR5 up-regulation contributed selectively to the apoptosis of astrocytes via the activation of phospholipase C and the release of calcium from intracellular stores as well as via the association with Homer proteins.
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Affiliation(s)
- Maryse Paquet
- J, Allyn Taylor Centre for Cell Biology, Robarts Research Institute, Department of Physiology and Pharmacology, The University of Western Ontario, 100 Perth Drive, London, ON, N6A 5K8, Canada
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Toyohara J, Sakata M, Fujinaga M, Yamasaki T, Oda K, Ishii K, Zhang MR, Moriguchi Jeckel CM, Ishiwata K. Preclinical and the first clinical studies on [11C]ITMM for mapping metabotropic glutamate receptor subtype 1 by positron emission tomography. Nucl Med Biol 2013; 40:214-20. [DOI: 10.1016/j.nucmedbio.2012.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 11/19/2012] [Accepted: 11/19/2012] [Indexed: 01/29/2023]
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Xie AX, Sun MY, Murphy T, Lauderdale K, Tiglao E, Fiacco TA. Bidirectional scaling of astrocytic metabotropic glutamate receptor signaling following long-term changes in neuronal firing rates. PLoS One 2012; 7:e49637. [PMID: 23166735 PMCID: PMC3499417 DOI: 10.1371/journal.pone.0049637] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 10/16/2012] [Indexed: 11/19/2022] Open
Abstract
Very little is known about the ability of astrocytic receptors to exhibit plasticity as a result of changes in neuronal activity. Here we provide evidence for bidirectional scaling of astrocytic group I metabotropic glutamate receptor signaling in acute mouse hippocampal slices following long-term changes in neuronal firing rates. Plasticity of astrocytic mGluRs was measured by recording spontaneous and evoked Ca2+ elevations in both astrocytic somata and processes. An exogenous astrocytic Gq G protein-coupled receptor was resistant to scaling, suggesting that the alterations in astrocyte Ca2+ signaling result from changes in activity of the surface mGluRs rather than a change in intracellular G protein signaling molecules. These findings suggest that astrocytes actively detect shifts in neuronal firing rates and adjust their receptor signaling accordingly. This type of long-term plasticity in astrocytes resembles neuronal homeostatic plasticity and might be important to ensure an optimal or expected level of input from neurons.
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Affiliation(s)
- Alison X. Xie
- Graduate Program in Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Min-Yu Sun
- Graduate Program in Cellular, Molecular, and Developmental Biology, University of California Riverside, Riverside, California, United States of America
| | - Thomas Murphy
- Graduate Program in Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Kelli Lauderdale
- Graduate Program in Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Elizabeth Tiglao
- Undergraduate Neuroscience Major, University of California Riverside, Riverside, California, United States of America
| | - Todd A. Fiacco
- Department of Cell Biology and Neuroscience and Center for Glial-Neuronal Interactions, University of California Riverside, Riverside, California, United States of America
- * E-mail:
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Hovelsø N, Sotty F, Montezinho LP, Pinheiro PS, Herrik KF, Mørk A. Therapeutic potential of metabotropic glutamate receptor modulators. Curr Neuropharmacol 2012; 10:12-48. [PMID: 22942876 PMCID: PMC3286844 DOI: 10.2174/157015912799362805] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2010] [Revised: 01/10/2011] [Accepted: 03/04/2011] [Indexed: 12/21/2022] Open
Abstract
Glutamate is the main excitatory neurotransmitter in the central nervous system (CNS) and is a major player in complex brain functions. Glutamatergic transmission is primarily mediated by ionotropic glutamate receptors, which include NMDA, AMPA and kainate receptors. However, glutamate exerts modulatory actions through a family of metabotropic G-protein-coupled glutamate receptors (mGluRs). Dysfunctions of glutamatergic neurotransmission have been implicated in the etiology of several diseases. Therefore, pharmacological modulation of ionotropic glutamate receptors has been widely investigated as a potential therapeutic strategy for the treatment of several disorders associated with glutamatergic dysfunction. However, blockade of ionotropic glutamate receptors might be accompanied by severe side effects due to their vital role in many important physiological functions. A different strategy aimed at pharmacologically interfering with mGluR function has recently gained interest. Many subtype selective agonists and antagonists have been identified and widely used in preclinical studies as an attempt to elucidate the role of specific mGluRs subtypes in glutamatergic transmission. These studies have allowed linkage between specific subtypes and various physiological functions and more importantly to pathological states. This article reviews the currently available knowledge regarding the therapeutic potential of targeting mGluRs in the treatment of several CNS disorders, including schizophrenia, addiction, major depressive disorder and anxiety, Fragile X Syndrome, Parkinson’s disease, Alzheimer’s disease and pain.
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Affiliation(s)
- N Hovelsø
- Department of Neurophysiology, H. Lundbeck A/S, Ottiliavej 9, 2500 Copenhagen-Valby, Denmark
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Prabowo AS, Anink JJ, Lammens M, Nellist M, van den Ouweland AMW, Adle-Biassette H, Sarnat HB, Flores-Sarnat L, Crino PB, Aronica E. Fetal brain lesions in tuberous sclerosis complex: TORC1 activation and inflammation. Brain Pathol 2012; 23:45-59. [PMID: 22805177 DOI: 10.1111/j.1750-3639.2012.00616.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 07/01/2012] [Indexed: 01/06/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutations in either the TSC1 or TSC2 genes and characterized by developmental brain abnormalities. We defined the spectrum of brain abnormalities in fetal TSC brain ranging from 23 to 38 gestational weeks. We hypothesized (i) prenatal activation of the target-of-rapamycin complex 1 (TORC1) signaling pathway; and (ii) activation of inflammatory pathways in fetal brain lesions. Immunocytochemical analysis of cortical tubers, as well as subependymal lesions in all cases confirmed the cell-associated activation of the TORC1 signaling pathway in both the cortical tubers and subependymal lesions (including a congenital subependymal giant cell astrocytoma) with expression of pS6, p4EBP1 and c-myc proteins, as well as of p70 S6 kinase 1. The lesions contained macrophages and T-lymphocytes; giant cells within the lesions expressed inflammatory response markers including major histocompatibility complex class I and II, Toll-like receptors (TLR) 2 and 4 and receptor for advanced glycation end products (RAGE). These observations indicate that brain malformations in TSC are likely a consequence of increased TORC1 activation during embryonic brain development. We also provide evidence supporting the possible immunogenicity of giant cells and the early activation of inflammatory pathways in TSC brain.
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Affiliation(s)
- Avanita S Prabowo
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam
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43
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Agulhon C, Sun MY, Murphy T, Myers T, Lauderdale K, Fiacco TA. Calcium Signaling and Gliotransmission in Normal vs. Reactive Astrocytes. Front Pharmacol 2012; 3:139. [PMID: 22811669 PMCID: PMC3395812 DOI: 10.3389/fphar.2012.00139] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/26/2012] [Indexed: 01/07/2023] Open
Abstract
A prominent area of neuroscience research over the past 20 years has been the acute modulation of neuronal synaptic activity by Ca2+-dependent release of the transmitters ATP, D-serine, and glutamate (called gliotransmitters) by astrocytes. Although the physiological relevance of this mechanism is under debate, emerging evidence suggests that there are critical factors in addition to Ca2+ that are required for gliotransmitters to be released from astrocytes. Interestingly, these factors include activated microglia and the proinflammatory cytokine Tumor Necrosis Factor α (TNFα), chemotactic cytokine Stromal cell-Derived Factor-1α (SDF-1α), and inflammatory mediator prostaglandin E2 (PGE2). Of note, microglial activation and release of inflammatory molecules from activated microglia and reactive astrocytes can occur within minutes of a triggering stimulus. Therefore, activation of astrocytes by inflammatory molecules combined with Ca2+ elevations may lead to gliotransmitter release, and be an important step in the early sequence of events contributing to hyperexcitability, excitotoxicity, and neurodegeneration in the damaged or diseased brain. In this review, we will first examine evidence questioning Ca2+-dependent gliotransmitter release from astrocytes in healthy brain tissue, followed by a close examination of recent work suggesting that Ca2+-dependent gliotransmitter release occurs as an early event in the development of neurological disorders and neuroinflammatory and neurodegenerative diseases.
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Affiliation(s)
- Cendra Agulhon
- UFR Biomédicale, CNRS UMR 8154, Université Paris Descartes Paris, France
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44
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Targeting metabotropic glutamate receptors in neuroimmune communication. Neuropharmacology 2012; 63:501-6. [PMID: 22640632 DOI: 10.1016/j.neuropharm.2012.05.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/15/2012] [Accepted: 05/17/2012] [Indexed: 01/13/2023]
Abstract
L-Glutamate (L-Glu) is the principal excitatory neurotransmitter in the Central Nervous System (CNS), where it regulates cellular and synaptic activity, neuronal plasticity, cell survival and other relevant functions. Glutamatergic neurotransmission is complex and involves both ionotropic (ligand-gated ion channels; iGluRs) and metabotropic receptors (G-protein coupled receptors). Recent evidence suggests that glutamatergic receptors are also expressed by immune cells, regulating the degree of cell activation. In this review we primarily focus on mGluRs and their role in the crosstalk between the central nervous and immune systems during neuroinflammation.
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45
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Zamecnik J, Homola A, Cicanic M, Kuncova K, Marusic P, Krsek P, Sykova E, Vargova L. The extracellular matrix and diffusion barriers in focal cortical dysplasias. Eur J Neurosci 2012; 36:2017-24. [PMID: 22536791 DOI: 10.1111/j.1460-9568.2012.08107.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Focal cortical dysplasias (FCDs) of the brain are recognized as a frequent cause of intractable epilepsy. To contribute to the current understanding of the mechanisms of epileptogenesis in FCD, our study provides evidence that not only cellular alterations and synaptic transmission, but also changed diffusion properties of the extracellular space (ECS), induced by modified extracellular matrix (ECM) composition and astrogliosis, might be involved in the generation or spread of seizures in FCD. The composition of the ECM in FCD and non-malformed cortex (in 163 samples from 62 patients) was analyzed immunohistochemically and correlated with the corresponding ECS diffusion parameter values determined with the real-time iontophoretic method in freshly resected cortex (i.e. the ECS volume fraction and the geometrical factor tortuosity, describing the hindrances to diffusion in the ECS). The ECS in FCD was shown to differ from that in non-malformed cortex, mainly by the increased accumulation of certain ECM molecules (tenascin R, tenascin C, and versican) or by their reduced expression (brevican), and by the presence of an increased number of astrocytic processes. The consequent increase of ECS diffusion barriers observed in both FCD type I and II (and, at the same time, the enlargement of the ECS volume in FCD type II) may alter the diffusion of neuroactive substances through the ECS, which mediates one of the important modes of intercellular communication in the brain - extrasynaptic volume transmission. Thus, the changed ECM composition and altered ECS diffusion properties might represent additional factors contributing to epileptogenicity in FCD.
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Affiliation(s)
- Josef Zamecnik
- Department of Pathology and Molecular Medicine, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, 150 06 Prague, Czech Republic.
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46
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Herman EJ, Bubser M, Conn PJ, Jones CK. Metabotropic glutamate receptors for new treatments in schizophrenia. Handb Exp Pharmacol 2012:297-365. [PMID: 23027420 DOI: 10.1007/978-3-642-25758-2_11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) represent exciting targets for the development of novel therapeutic agents for schizophrenia. Recent studies indicate that selective activation of specific mGluR subtypes may provide potential benefits for not only the positive symptoms, but also the negative symptoms and cognitive impairments observed in individuals with schizophrenia. Although optimization of traditional orthosteric agonists may still offer a feasible approach for the activation of mGluRs, important progress has been made in the discovery of novel subtype-selective allosteric ligands, including positive allosteric modulators (PAMs) of mGluR2 and mGluR5. These allosteric mGluR ligands have improved properties for clinical development and have served as key preclinical tools for a more in-depth understanding of the potential roles of these different mGluR subtypes for the treatment of schizophrenia.
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Affiliation(s)
- E J Herman
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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47
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Crino PB. mTOR: A pathogenic signaling pathway in developmental brain malformations. Trends Mol Med 2011; 17:734-42. [DOI: 10.1016/j.molmed.2011.07.008] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 07/19/2011] [Accepted: 07/21/2011] [Indexed: 11/16/2022]
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Casula M, Iyer AM, Spliet WGM, Anink JJ, Steentjes K, Sta M, Troost D, Aronica E. Toll-like receptor signaling in amyotrophic lateral sclerosis spinal cord tissue. Neuroscience 2011; 179:233-43. [PMID: 21303685 DOI: 10.1016/j.neuroscience.2011.02.001] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/31/2011] [Accepted: 02/01/2011] [Indexed: 02/07/2023]
Abstract
Increasing evidence indicates that inflammatory responses could play a critical role in the pathogenesis of motor neuron injury in amyotrophic lateral sclerosis (ALS). Recent findings have underlined the role of Toll-like receptors (TLRs) and the receptor for advanced glycation endproducts (RAGE) in the regulation of both innate and adaptive immunity in different pathologies associated with neuroinflammation. In the present study we investigated the expression and cellular distribution of TLR2, TLR4, RAGE and their endogenous ligand high mobility group box 1 (HMGB1) in the spinal cord of control (n=6) and sporadic ALS (n=12) patients. The immunohistochemical analysis of TLR2, TLR4 and RAGE showed increased expression in reactive glial cells in both gray (ventral horn) and white matter of ALS spinal cord. TLR2 was predominantly detected in cells of the microglia/macrophage lineage, whereas the TLR4 and RAGE was strongly expressed in astrocytes. Real-time quantitative PCR analysis confirmed the increased expression of both TLR2 and TLR4 and HMGB1 mRNA level in ALS patients. In ALS spinal cord, HMGB1 signal is increased in the cytoplasm of reactive glia, indicating a possible release of this molecule from glial cells. Our findings show increased expression of TLR2, TLR4, RAGE and HMGB1 in reactive glia in human ALS spinal cord, suggesting activation of the TLR/RAGE signaling pathways. The activation of these pathways may contribute to the progression of inflammation, resulting in motor neuron injury. In this context, future studies, using animal models, will be important to achieve a better understanding of these signaling pathways in ALS in view of the development of new therapeutic strategies.
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Affiliation(s)
- M Casula
- Department of (Neuro) Pathology, Academic Medical Center, University of Amsterdam, The Netherlands
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49
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DeLorenzo C, Milak MS, Brennan KG, Kumar JSD, Mann JJ, Parsey RV. In vivo positron emission tomography imaging with [¹¹C]ABP688: binding variability and specificity for the metabotropic glutamate receptor subtype 5 in baboons. Eur J Nucl Med Mol Imaging 2011; 38:1083-94. [PMID: 21279350 DOI: 10.1007/s00259-010-1723-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 12/17/2010] [Indexed: 11/30/2022]
Abstract
PURPOSE Metabotropic glutamate receptor subtype 5 (mGluR5) dysfunction has been implicated in several disorders. [(11)C]ABP688, a positron emission tomography (PET) ligand targeting mGluR5, could be a valuable tool in the development of novel therapeutics for these disorders by establishing in vivo drug occupancy. Due to safety concerns in humans, these studies may be performed in nonhuman primates. Therefore, in vivo characterization of [(11)C]ABP688 in nonhuman primates is essential. METHODS Test-retest studies were performed in baboons (Papio anubis) to compare modeling approaches and determine the optimal reference region. The mGluR5-specific antagonist 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine (MTEP) was then used in test-block studies, in which ligand binding was measured before and after MTEP administration. Test/block data were analyzed both by calculating changes in binding and using a graphical approach, which allowed estimation of both MTEP occupancy and nonspecific binding. RESULTS Test-retest results, which have not been previously reported for [(11)C]ABP688, indicated that [(11)C]ABP688 variability is low using an unconstrained two-tissue compartment model. The most appropriate, though not ideal, reference region was found to be the gray matter of the cerebellum. Using these optimal modeling techniques on the test/block data, about 90% occupancy was estimated by the graphical approach. CONCLUSION These studies are the first to demonstrate the specificity of [(11)C]ABP688 for mGluR5 with in vivo PET in nonhuman primates. The results indicate that, in baboons, occupancy of mGluR5 is detectable by in vivo PET, a useful finding for proceeding to human studies, or performing further baboon studies, quantifying the in vivo occupancy of novel therapeutics targeting mGluR5.
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Affiliation(s)
- Christine DeLorenzo
- Division of Molecular Imaging and Neuropathology, Department of Psychiatry, Columbia University College of Physicians and Surgeons, NYSPI Mail Unit 42, 1051 Riverside Drive, New York, NY, USA.
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50
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Nicoletti F, Bockaert J, Collingridge GL, Conn PJ, Ferraguti F, Schoepp DD, Wroblewski JT, Pin JP. Metabotropic glutamate receptors: from the workbench to the bedside. Neuropharmacology 2010; 60:1017-41. [PMID: 21036182 DOI: 10.1016/j.neuropharm.2010.10.022] [Citation(s) in RCA: 476] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 10/15/2010] [Accepted: 10/21/2010] [Indexed: 12/24/2022]
Abstract
Metabotropic glutamate (mGlu) receptors were discovered in the mid 1980s and originally described as glutamate receptors coupled to polyphosphoinositide hydrolysis. Almost 6500 articles have been published since then, and subtype-selective mGlu receptor ligands are now under clinical development for the treatment of a variety of disorders such as Fragile-X syndrome, schizophrenia, Parkinson's disease and L-DOPA-induced dyskinesias, generalized anxiety disorder, chronic pain, and gastroesophageal reflux disorder. Prof. Erminio Costa was linked to the early times of the mGlu receptor history, when a few research groups challenged the general belief that glutamate could only activate ionotropic receptors and all metabolic responses to glutamate were secondary to calcium entry. This review moves from those nostalgic times to the most recent advances in the physiology and pharmacology of mGlu receptors, and highlights the role of individual mGlu receptor subtypes in the pathophysiology of human disorders. This article is part of a Special Issue entitled 'Trends in neuropharmacology: in memory of Erminio Costa'.
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Affiliation(s)
- F Nicoletti
- Department of Physiology and Pharmacology, University of Rome, Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy.
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