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Scheffer IE, Zuberi S, Mefford HC, Guerrini R, McTague A. Developmental and epileptic encephalopathies. Nat Rev Dis Primers 2024; 10:61. [PMID: 39237642 DOI: 10.1038/s41572-024-00546-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/29/2024] [Indexed: 09/07/2024]
Abstract
Developmental and epileptic encephalopathies, the most severe group of epilepsies, are characterized by seizures and frequent epileptiform activity associated with developmental slowing or regression. Onset typically occurs in infancy or childhood and includes many well-defined epilepsy syndromes. Patients have wide-ranging comorbidities including intellectual disability, psychiatric features, such as autism spectrum disorder and behavioural problems, movement and musculoskeletal disorders, gastrointestinal and sleep problems, together with an increased mortality rate. Problems change with age and patients require substantial support throughout life, placing a high psychosocial burden on parents, carers and the community. In many patients, the aetiology can be identified, and a genetic cause is found in >50% of patients using next-generation sequencing technologies. More than 900 genes have been identified as monogenic causes of developmental and epileptic encephalopathies and many cell components and processes have been implicated in their pathophysiology, including ion channels and transporters, synaptic proteins, cell signalling and metabolism and epigenetic regulation. Polygenic risk score analyses have shown that common variants also contribute to phenotypic variability. Holistic management, which encompasses antiseizure therapies and care for multimorbidities, is determined both by epilepsy syndrome and aetiology. Identification of the underlying aetiology enables the development of precision medicines to improve the long-term outcome of patients with these devastating diseases.
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Affiliation(s)
- Ingrid E Scheffer
- Epilepsy Research Centre, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia.
- Florey and Murdoch Children's Research Institutes, Melbourne, Victoria, Australia.
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia.
| | - Sameer Zuberi
- Paediatric Neurosciences Research Group, School of Health & Wellbeing, University of Glasgow, Glasgow, UK
- Paediatric Neurosciences, Royal Hospital for Children, Glasgow, UK
| | - Heather C Mefford
- Center for Paediatric Neurological Disease Research, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Renzo Guerrini
- Neuroscience Department, Children's Hospital Meyer IRCCS, Florence, Italy
- University of Florence, Florence, Italy
| | - Amy McTague
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
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Shin HJ, Ko A, Kim SH, Lee JS, Kang HC. Unusual Voltage-Gated Sodium and Potassium Channelopathies Related to Epilepsy. J Clin Neurol 2024; 20:402-411. [PMID: 38951973 PMCID: PMC11220354 DOI: 10.3988/jcn.2023.0435] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/03/2024] [Accepted: 01/23/2024] [Indexed: 07/03/2024] Open
Abstract
BACKGROUND AND PURPOSE There is extensive literature on monogenic epilepsies caused by mutations in familiar channelopathy genes such as SCN1A. However, information on other less-common channelopathy genes is scarce. This study aimed to explore the genetic and clinical characteristics of patients diagnosed with unusual voltage-gated sodium and potassium channelopathies related to epilepsy. METHODS This observational, retrospective study analyzed pediatric patients with epilepsy who carried pathogenic variants of unusual voltage-gated sodium and potassium channelopathy genes responsible for seizure-associated phenotypes. Targeted next-generation sequencing (NGS) panel tests were performed between November 2016 and June 2022 at Severance Children's Hospital, Seoul, South Korea. Clinical characteristics and the treatment responses to different types of antiseizure medications were further analyzed according to different types of gene mutation. RESULTS This study included 15 patients with the following unusual voltage-gated sodium and potassium channelopathy genes: SCN3A (n=1), SCN4A (n=1), KCNA1 (n=1), KCNA2 (n=4), KCNB1 (n=6), KCNC1 (n=1), and KCNMA1 (n=1). NGS-based genetic testing identified 13 missense mutations (87%), 1 splice-site variant (7%), and 1 copy-number variant (7%). Developmental and epileptic encephalopathy was diagnosed in nine (60%) patients. Seizure freedom was eventually achieved in eight (53%) patients, whereas seizures persisted in seven (47%) patients. CONCLUSIONS Our findings broaden the genotypic and phenotypic spectra of less-common voltage-gated sodium and potassium channelopathies associated with epilepsy.
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Affiliation(s)
- Hui Jin Shin
- Division of Pediatric Neurology, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Ara Ko
- Division of Pediatric Neurology, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Se Hee Kim
- Division of Pediatric Neurology, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Joon Soo Lee
- Division of Pediatric Neurology, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hoon-Chul Kang
- Division of Pediatric Neurology, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea.
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The Role of Glutamate Receptors in Epilepsy. Biomedicines 2023; 11:biomedicines11030783. [PMID: 36979762 PMCID: PMC10045847 DOI: 10.3390/biomedicines11030783] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/26/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Glutamate is an essential excitatory neurotransmitter in the central nervous system, playing an indispensable role in neuronal development and memory formation. The dysregulation of glutamate receptors and the glutamatergic system is involved in numerous neurological and psychiatric disorders, especially epilepsy. There are two main classes of glutamate receptor, namely ionotropic and metabotropic (mGluRs) receptors. The former stimulate fast excitatory neurotransmission, are N-methyl-d-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), and kainate; while the latter are G-protein-coupled receptors that mediate glutamatergic activity via intracellular messenger systems. Glutamate, glutamate receptors, and regulation of astrocytes are significantly involved in the pathogenesis of acute seizure and chronic epilepsy. Some glutamate receptor antagonists have been shown to be effective for the treatment of epilepsy, and research and clinical trials are ongoing.
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Gataullina S, Galvani G, Touchet S, Nous C, Lemaire E, Laschet J, Chiron C, Dulac O, Dossi E, Brion JD, Messaoudi S, Alami M, Huberfeld G. GluN2C
selective inhibition is a target to develop new antiepileptic compounds. Epilepsia 2022; 63:2911-2924. [PMID: 36054371 DOI: 10.1111/epi.17396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/17/2022] [Accepted: 08/17/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Many early-onset epilepsies present as developmental and epileptic encephalopathy associated with refractory seizures, altered psychomotor development, and disorganized interictal cortical activity. Abnormal upregulation of specific N-methyl-d-aspartate receptor (NMDA-R) subunits is being disentangled as one of the mechanisms of severe early-onset epilepsies. In tuberous sclerosis complex (TSC), upregulation of the GluN2C subunit of the NMDA-R with slow deactivation kinetic results in increased neuronal excitation and synchronization. METHODS Starting from an available GluN2C/D antagonist, NMDA-R-modulating compounds were developed and screened using a patch clamp on neuronal culture to select those with the strongest inhibitory effect on glutamatergic NMDA currents. For these selected compounds, blood pharmacokinetics and passage through the blood-brain barrier were studied. We tested the effect of the most promising compounds on epileptic activity in Tsc1+/- mice brain slices with multielectrode array, and then in vivo at postnatal ages P14-P17, comparable with the usual age at epilepsy onset in human TSC. RESULTS Using a double-electrode voltage clamp on isolated NMDA currents, we identified the most prominent antagonists of the GluN2C subunit with no effect on GluN2A as a means of preventing side effects. The best compound passing through the blood-brain barrier was selected. Applied in vivo in six Tsc1+/- mice at P14-P17, this compound reduced or completely stopped spontaneous seizures in four of them, and decreased the background activity disorganization. Furthermore, ictal-like discharges stopped on a human brain sample from an infant with epilepsy due to TSC. INTERPRETATION Subunit-selective inhibition is a valuable target for developing drugs for severe epilepsies resulting from an upregulation of NMDA-R subunit-mediated transmission.
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Affiliation(s)
- S. Gataullina
- Service d’explorations fonctionnelles multidisciplinaires Centre de médecine du sommeil, Antoine Béclère Hospital, APHP, Université Paris Saclay Clamart France
| | - G. Galvani
- AdPueriVitam (APV), Antony France
- Université de Lorraine CNRS, L2CM Nancy France
| | - S. Touchet
- AdPueriVitam (APV), Antony France
- Université de Lorraine CNRS, L2CM Nancy France
| | - C. Nous
- Institut de la Vision, UFR Sciences et Technologies Paris France
| | | | | | - C. Chiron
- Inserm U1141, Paris & APHP, Neuropediatrics, Necker Hospital Paris France
| | - O. Dulac
- AdPueriVitam (APV), Antony France
| | - E. Dossi
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Université PSL Paris France
| | - J. D. Brion
- Université Paris‐Saclay CNRS UMR 8076, BioCIS Châtenay‐Malabry France
| | - S. Messaoudi
- Université Paris‐Saclay CNRS UMR 8076, BioCIS Châtenay‐Malabry France
| | - M. Alami
- Université Paris‐Saclay CNRS UMR 8076, BioCIS Châtenay‐Malabry France
| | - G. Huberfeld
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Université PSL Paris France
- Neurology Department, Hôpital Fondation Adolphe de Rothschild Paris France
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Marafi D, Fatih JM, Kaiyrzhanov R, Ferla MP, Gijavanekar C, Al-Maraghi A, Liu N, Sites E, Alsaif HS, Al-Owain M, Zakkariah M, El-Anany E, Guliyeva U, Guliyeva S, Gaba C, Haseeb A, Alhashem AM, Danish E, Karageorgou V, Beetz C, Subhi AA, Mullegama SV, Torti E, Sebastin M, Breilyn MS, Duberstein S, Abdel-Hamid MS, Mitani T, Du H, Rosenfeld JA, Jhangiani SN, Coban Akdemir Z, Gibbs RA, Taylor JC, Fakhro KA, Hunter JV, Pehlivan D, Zaki MS, Gleeson JG, Maroofian R, Houlden H, Posey JE, Sutton VR, Alkuraya FS, Elsea SH, Lupski JR. Biallelic variants in SLC38A3 encoding a glutamine transporter cause epileptic encephalopathy. Brain 2022; 145:909-924. [PMID: 34605855 PMCID: PMC9050560 DOI: 10.1093/brain/awab369] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 07/13/2021] [Accepted: 08/26/2021] [Indexed: 11/14/2022] Open
Abstract
The solute carrier (SLC) superfamily encompasses >400 transmembrane transporters involved in the exchange of amino acids, nutrients, ions, metals, neurotransmitters and metabolites across biological membranes. SLCs are highly expressed in the mammalian brain; defects in nearly 100 unique SLC-encoding genes (OMIM: https://www.omim.org) are associated with rare Mendelian disorders including developmental and epileptic encephalopathy and severe neurodevelopmental disorders. Exome sequencing and family-based rare variant analyses on a cohort with neurodevelopmental disorders identified two siblings with developmental and epileptic encephalopathy and a shared deleterious homozygous splicing variant in SLC38A3. The gene encodes SNAT3, a sodium-coupled neutral amino acid transporter and a principal transporter of the amino acids asparagine, histidine, and glutamine, the latter being the precursor for the neurotransmitters GABA and glutamate. Additional subjects with a similar developmental and epileptic encephalopathy phenotype and biallelic predicted-damaging SLC38A3 variants were ascertained through GeneMatcher and collaborations with research and clinical molecular diagnostic laboratories. Untargeted metabolomic analysis was performed to identify novel metabolic biomarkers. Ten individuals from seven unrelated families from six different countries with deleterious biallelic variants in SLC38A3 were identified. Global developmental delay, intellectual disability, hypotonia, and absent speech were common features while microcephaly, epilepsy, and visual impairment were present in the majority. Epilepsy was drug-resistant in half. Metabolomic analysis revealed perturbations of glutamate, histidine, and nitrogen metabolism in plasma, urine, and CSF of selected subjects, potentially representing biomarkers of disease. Our data support the contention that SLC38A3 is a novel disease gene for developmental and epileptic encephalopathy and illuminate the likely pathophysiology of the disease as perturbations in glutamine homeostasis.
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Affiliation(s)
- Dana Marafi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pediatrics, Faculty of Medicine, Kuwait University, P.O. Box 24923, 13110 Safat, Kuwait
- Correspondence to: Dana Marafi, MD, MSc Department of Pediatrics, Faculty of Medicine, Kuwait University P.O. Box 24923, 13110 Safat, Kuwait E-mail:
| | - Jawid M Fatih
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Rauan Kaiyrzhanov
- Department of Neuromuscular Disorders Institute of Neurology, University College London, Queen Square, London, UK
| | - Matteo P Ferla
- NIHR Oxford Biomedical Research Centre, Oxford OX4 2PG, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Charul Gijavanekar
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Baylor Genetics Laboratory, Houston, TX 77030, USA
| | | | - Ning Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Baylor Genetics Laboratory, Houston, TX 77030, USA
| | - Emily Sites
- Division of Molecular and Human Genetics, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Hessa S Alsaif
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
| | - Mohammad Al-Owain
- Department of Medical Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University 11533, Riyadh, Saudi Arabia
| | - Mohamed Zakkariah
- Section of Child Neurology, Department of Pediatrics, Al-adan Hospital, Riqqa, Kuwait
| | - Ehab El-Anany
- Section of Child Neurology, Department of Pediatrics, Al-adan Hospital, Riqqa, Kuwait
| | | | | | - Colette Gaba
- Department of Pediatrics, Bon Secours Mercy Health, Toledo, OH 43608, USA
| | - Ateeq Haseeb
- Mercy Children’s Hospital, Toledo, OH 43608, USA
| | - Amal M Alhashem
- Division of Medical Genetic and Metabolic Medicine, Department of Pediatrics, Prince Sultan Medical Military City, Riyadh, Saudi Arabia
| | - Enam Danish
- Department of Ophthalmology, King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia
| | | | | | - Alaa A Subhi
- Neurosciences Department, King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia
| | | | | | - Monisha Sebastin
- Albert Einstein College of Medicine and the Children's Hospital at Montefiore, Bronx, New York 10467, USA
- Division of Genetics, Department of Pediatrics, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York, 10467, USA
| | - Margo Sheck Breilyn
- Albert Einstein College of Medicine and the Children's Hospital at Montefiore, Bronx, New York 10467, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Susan Duberstein
- Isabelle Rapin Division of Child Neurology in the Saul R Korey Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Mohamed S Abdel-Hamid
- Department of Medical Molecular Genetics, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Tadahiro Mitani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Haowei Du
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Baylor Genetics Laboratory, Houston, TX 77030, USA
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zeynep Coban Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Human Genetics Center, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jenny C Taylor
- NIHR Oxford Biomedical Research Centre, Oxford OX4 2PG, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Khalid A Fakhro
- Department of Human Genetics, Sidra Medicine, Doha 26999, Qatar
- Department of Genetic Medicine, Weill Cornell Medical College, Doha, Qatar
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha 34110, Qatar
| | - Jill V Hunter
- E.B. Singleton Department of Pediatric Radiology, Texas Children’s Hospital, Houston, TX 77030, USA
- Department of Radiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children's Hospital, Houston, TX 77030, USA
- Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Maha S Zaki
- Department of Clinical Genetics, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Joseph G Gleeson
- Rady Children's Institute for Genomic Medicine, Howard Hughes Medical Institute, University of California, San Diego, CA 92123, USA
| | - Reza Maroofian
- Department of Neuromuscular Disorders Institute of Neurology, University College London, Queen Square, London, UK
| | - Henry Houlden
- Department of Neuromuscular Disorders Institute of Neurology, University College London, Queen Square, London, UK
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Baylor Genetics Laboratory, Houston, TX 77030, USA
- Texas Children's Hospital, Houston, TX 77030, USA
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Baylor Genetics Laboratory, Houston, TX 77030, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children's Hospital, Houston, TX 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
- Correspondence may also be addressed to: James R. Lupski, MD, PhD, DSc (hon) Department of Molecular and Human Genetics, Baylor College of Medicine One Baylor Plaza, Room 604B, Houston, TX 77030, USA E-mail:
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Bai YF, Zeng C, Jia M, Xiao B. Molecular mechanisms of topiramate and its clinical value in epilepsy. Seizure 2022; 98:51-56. [DOI: 10.1016/j.seizure.2022.03.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 03/29/2022] [Accepted: 03/31/2022] [Indexed: 10/18/2022] Open
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Biembengut ÍV, Silva ILZ, Souza TDACBD, Shigunov P. Cytoplasmic FMR1 interacting protein (CYFIP) family members and their function in neural development and disorders. Mol Biol Rep 2021; 48:6131-6143. [PMID: 34327661 DOI: 10.1007/s11033-021-06585-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/20/2021] [Indexed: 11/25/2022]
Abstract
In humans, the cytoplasmic FMR1 interacting protein (CYFIP) family is composed of CYFIP1 and CYFIP2. Despite their high similarity and shared interaction with many partners, CYFIP1 and CYFIP2 act at different points in cellular processes. CYFIP1 and CYFIP2 have different expression levels in human tissues, and knockout animals die at different time points of development. CYFIP1, similar to CYFIP2, acts in the WAVE regulatory complex (WRC) and plays a role in actin dynamics through the activation of the Arp2/3 complex and in a posttranscriptional regulatory complex with the fragile X mental retardation protein (FMRP). Previous reports have shown that CYFIP1 and CYFIP2 may play roles in posttranscriptional regulation in different ways. While CYFIP1 is involved in translation initiation via the 5'UTR, CYFIP2 may regulate mRNA expression via the 3'UTR. In addition, this CYFIP protein family is involved in neural development and maturation as well as in different neural disorders, such as intellectual disabilities, autistic spectrum disorders, and Alzheimer's disease. In this review, we map diverse studies regarding the functions, regulation, and implications of CYFIP proteins in a series of molecular pathways. We also highlight mutations and their structural effects both in functional studies and in neural diseases.
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Affiliation(s)
- Ísis Venturi Biembengut
- Carlos Chagas Institute-FIOCRUZ-PR, Rua Prof. Algacyr Munhoz Mader, 3775, CIC, Curitiba, Paraná, 81830-010, Brazil
| | | | | | - Patrícia Shigunov
- Carlos Chagas Institute-FIOCRUZ-PR, Rua Prof. Algacyr Munhoz Mader, 3775, CIC, Curitiba, Paraná, 81830-010, Brazil.
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Knoflach F, Bertrand D. Pharmacological modulation of GABA A receptors. Curr Opin Pharmacol 2021; 59:3-10. [PMID: 34020139 DOI: 10.1016/j.coph.2021.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 04/13/2021] [Indexed: 10/21/2022]
Abstract
Ligand-gated ion channels are integral membrane proteins that activate through a change in conformation upon transmitter binding and were identified as key players of brain function. GABAA receptors are major inhibitory ligand-gated ion channels of this protein family. They are the target of many therapeutic compounds widely used in the clinic and continue to attract the attention of academic and pharmaceutical laboratories. Advances in the knowledge of the structure of GABAA receptors at the molecular level with unprecedented resolution enabled the determination of the binding sites of many allosteric modulators revealing the nature of their interactions with the receptors. Herein, we review the latest findings on allosteric modulation of GABAA receptors and their relevance to drug discovery.
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Affiliation(s)
- Frédéric Knoflach
- F. Hoffmann-La Roche Ltd., Neuroscience & Rare Diseases (NRD) Research, Roche Innovation Center Basel, Basel, 4070, Switzerland
| | - Daniel Bertrand
- HiQScreen Sàrl, 6 rte de Compois, Vésenaz, Geneva, 1222, Switzerland.
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Guery D, Rheims S. Is the mechanism of action of antiseizure drugs a key element in the choice of treatment? Fundam Clin Pharmacol 2020; 35:552-563. [PMID: 33090514 DOI: 10.1111/fcp.12614] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/02/2020] [Accepted: 10/02/2020] [Indexed: 12/20/2022]
Abstract
About 25 antiseizure drugs are available for the treatment of patients with epilepsy. The choice of the most suited drug for a specific patient is primarily based on the results of the pivotal randomized clinical trials and on the patient's characteristics and comorbidities. Whether or not the mechanism of action of the antiseizure drugs should be also taken into account to better predict the patient's response to the treatment remains a matter of debate. Despite the apparent complexity and diversity of antiseizure drug mechanisms of action, the reality unfortunately remains that they are very close, in particular with regard to their relationship with the pathophysiology of epilepsy. With the only exception of the association between lamotrigine and sodium valproate, there are no clinical data that formally support a synergistic association between certain antiseizure drugs in terms of efficacy. However, anticipating risk of adverse events by limiting as far as possible the combination of drugs, which share the same mechanisms of action, is undoubtedly an important driver of daily therapeutic decisions.
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Affiliation(s)
- Deborah Guery
- Department of Functional Neurology and Epileptology, Hospices Civils de Lyon and University of Lyon, Lyon, France
| | - Sylvain Rheims
- Department of Functional Neurology and Epileptology, Hospices Civils de Lyon and University of Lyon, Lyon, France.,Lyon's Neuroscience Research Center, INSERM U1028 / CNRS UMR 5292, Lyon, France.,Epilepsy Institute, Lyon, France
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Absalom NL, Liao VWY, Kothur K, Indurthi DC, Bennetts B, Troedson C, Mohammad SS, Gupta S, McGregor IS, Bowen MT, Lederer D, Mary S, De Waele L, Jansen K, Gill D, Kurian MA, McTague A, Møller RS, Ahring PK, Dale RC, Chebib M. Gain-of-function GABRB3 variants identified in vigabatrin-hypersensitive epileptic encephalopathies. Brain Commun 2020; 2:fcaa162. [PMID: 33585817 PMCID: PMC7869430 DOI: 10.1093/braincomms/fcaa162] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/31/2020] [Accepted: 08/28/2020] [Indexed: 01/06/2023] Open
Abstract
Variants in the GABRB3 gene encoding the β3-subunit of the γ-aminobutyric acid type A ( receptor are associated with various developmental and epileptic encephalopathies. Typically, these variants cause a loss-of-function molecular phenotype whereby γ-aminobutyric acid has reduced inhibitory effectiveness leading to seizures. Drugs that potentiate inhibitory GABAergic activity, such as nitrazepam, phenobarbital or vigabatrin, are expected to compensate for this and thereby reduce seizure frequency. However, vigabatrin, a drug that inhibits γ-aminobutyric acid transaminase to increase tonic γ-aminobutyric acid currents, has mixed success in treating seizures in patients with GABRB3 variants: some patients experience seizure cessation, but there is hypersensitivity in some patients associated with hypotonia, sedation and respiratory suppression. A GABRB3 variant that responds well to vigabatrin involves a truncation variant (p.Arg194*) resulting in a clear loss-of-function. We hypothesized that patients with a hypersensitive response to vigabatrin may exhibit a different γ-aminobutyric acid A receptor phenotype. To test this hypothesis, we evaluated the phenotype of de novo variants in GABRB3 (p.Glu77Lys and p.Thr287Ile) associated with patients who are clinically hypersensitive to vigabatrin. We introduced the GABRB3 p.Glu77Lys and p.Thr287Ile variants into a concatenated synaptic and extrasynaptic γ-aminobutyric acid A receptor construct, to resemble the γ-aminobutyric acid A receptor expression by a patient heterozygous for the GABRB3 variant. The mRNA of these constructs was injected into Xenopus oocytes and activation properties of each receptor measured by two-electrode voltage clamp electrophysiology. Results showed an atypical gain-of-function molecular phenotype in the GABRB3 p.Glu77Lys and p.Thr287Ile variants characterized by increased potency of γ-aminobutyric acid A without change to the estimated maximum open channel probability, deactivation kinetics or absolute currents. Modelling of the activation properties of the receptors indicated that either variant caused increased chloride flux in response to low concentrations of γ-aminobutyric acid that mediate tonic currents. We therefore propose that the hypersensitivity reaction to vigabatrin is a result of GABRB3 variants that exacerbate GABAergic tonic currents and caution is required when prescribing vigabatrin. In contrast, drug strategies increasing tonic currents in loss-of-function variants are likely to be a safe and effective therapy. This study demonstrates that functional genomics can explain beneficial and adverse anti-epileptic drug effects, and propose that vigabatrin should be considered in patients with clear loss-of-function GABRB3 variants.
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Affiliation(s)
- Nathan L Absalom
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Vivian W Y Liao
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Kavitha Kothur
- Kids Neuroscience Centre at The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Dinesh C Indurthi
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Bruce Bennetts
- Department of Molecular Genetics, The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
- Discipline of Paediatrics and Adolescent Health, The Children's Hospital at Westmead Clinical School, The University of Sydney, 2145, Australia
| | - Christopher Troedson
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Shekeeb S Mohammad
- Kids Neuroscience Centre at The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Sachin Gupta
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Iain S McGregor
- Faculty of Science, Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Michael T Bowen
- Faculty of Science, Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Damien Lederer
- Institute of Pathology and Genetics, Center for Human Genetics, Gosselies 6041, Belgium
| | - Sandrine Mary
- Institute of Pathology and Genetics, Center for Human Genetics, Gosselies 6041, Belgium
| | - Liesbeth De Waele
- Department of Development and Regeneration, KULeuven, Leuven 3000, Belgium
| | - Katrien Jansen
- Department of Development and Regeneration, KULeuven, Leuven 3000, Belgium
| | - Deepak Gill
- Kids Neuroscience Centre at The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Manju A Kurian
- Molecular Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1E 6BT, UK
- Department of Neurology, Great Ormond Street Hospital for Children, London WC1N 3JH, UK
| | - Amy McTague
- Molecular Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1E 6BT, UK
- Department of Neurology, Great Ormond Street Hospital for Children, London WC1N 3JH, UK
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Dianalund 4293, Denmark
- Department of Regional Health Research, University of Southern Denmark, Odense 5230, Denmark
| | - Philip K Ahring
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Russell C Dale
- Kids Neuroscience Centre at The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Mary Chebib
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
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Cho SJ, Newton J, Li T, Khandai P, Luta G, Lovinger DM, N'Gouemo P. Prenatal alcohol exposure in the second trimester-equivalent increases the seizure susceptibility in developing rats. Alcohol 2020; 85:153-164. [PMID: 32114257 DOI: 10.1016/j.alcohol.2020.01.005] [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: 10/29/2018] [Revised: 01/27/2020] [Accepted: 01/27/2020] [Indexed: 10/24/2022]
Abstract
We have previously reported that prenatal alcohol exposure (PAE) in the 2nd trimester-equivalent of gestation is associated with increased N-methyl-d-aspartate (NMDA)-induced generalized tonic-clonic seizures (GTCSs) prevalence in postpartum developing rats. Whether the 1st trimester-equivalent of gestation is also a vulnerable period for developing GTCSs following PAE is unknown. Here, we investigated the effects of a single episode of PAE at embryonic day 8 (E8, in the 1st trimester-equivalent) or E18 (in the 2nd trimester-equivalent) on NMDA-induced seizures in developing rats at postnatal day 7 (P7, the equivalent of preterm newborns) and P15 (the equivalent of term infants). Pregnant Sprague-Dawley rats were given a single oral dose of ethanol (5 g/kg body weight) at E8 or E18 and the postpartum rats were tested for the susceptibility to NMDA-induced seizures at either P7 or P15. NMDA-induced seizures consisted of wild running-like behavior (WRLB), flexion seizures (FSs), clonic seizures (CSs), GTCSs, and tonic seizures (TSs); these seizures were observed in both control-treated and PAE-treated, male and female, P7 and P15 rats. Quantification reveals that the overall prevalence of CSs, GTCSs and TSs occurrence were significantly increased in the E18-PAE group compared to E8-PAE group, adjusting for sex and postnatal day. Furthermore, the overall prevalence of FSs and TSs occurrence was significantly increased in PAE-treated males compared to females, adjusting for embryonic stage and postnatal day. The overall prevalence of WRLB and FSs occurrence was also increased in PAE-P7 rats compared to PAE-P15 rats, adjusting for sex and embryonic stage. We conclude that the susceptibility to develop GTCSs was higher when PAE occurred in the 2nd rather than in the 1st trimester-equivalent of gestation.
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D'Adamo MC, Liantonio A, Conte E, Pessia M, Imbrici P. Ion Channels Involvement in Neurodevelopmental Disorders. Neuroscience 2020; 440:337-359. [PMID: 32473276 DOI: 10.1016/j.neuroscience.2020.05.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/16/2020] [Accepted: 05/19/2020] [Indexed: 12/14/2022]
Abstract
Inherited and sporadic mutations in genes encoding for brain ion channels, affecting membrane expression or biophysical properties, have been associated with neurodevelopmental disorders characterized by epilepsy, cognitive and behavioral deficits with significant phenotypic and genetic heterogeneity. Over the years, the screening of a growing number of patients and the functional characterization of newly identified mutations in ion channels genes allowed to recognize new phenotypes and to widen the clinical spectrum of known diseases. Furthermore, advancements in understanding disease pathogenesis at atomic level or using patient-derived iPSCs and animal models have been pivotal to orient therapeutic intervention and to put the basis for the development of novel pharmacological options for drug-resistant disorders. In this review we will discuss major improvements and critical issues concerning neurodevelopmental disorders caused by dysfunctions in brain sodium, potassium, calcium, chloride and ligand-gated ion channels.
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Affiliation(s)
- Maria Cristina D'Adamo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Malta
| | | | - Elena Conte
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Italy
| | - Mauro Pessia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Malta; Department of Physiology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Italy.
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A Novel WAC Loss of Function Mutation in an Individual Presenting with Encephalopathy Related to Status Epilepticus during Sleep (ESES). Genes (Basel) 2020; 11:genes11030344. [PMID: 32214004 PMCID: PMC7141116 DOI: 10.3390/genes11030344] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/20/2020] [Accepted: 03/22/2020] [Indexed: 01/10/2023] Open
Abstract
WAC (WW Domain Containing Adaptor With Coiled-Coil) mutations have been reported in only 20 individuals presenting a neurodevelopmental disorder characterized by intellectual disability, neonatal hypotonia, behavioral problems, and mildly dysmorphic features. Using targeted deep sequencing, we screened a cohort of 630 individuals with variable degrees of intellectual disability and identified five WAC rare variants: two variants were inherited from healthy parents; two previously reported de novo mutations, c.1661_1664del (p.Ser554*) and c.374C>A (p.Ser125*); and a novel c.381+2T>C variant causing the skipping of exon 4 of the gene, inherited from a reportedly asymptomatic father with somatic mosaicism. A phenotypic evaluation of this individual evidenced areas of cognitive and behavioral deficits. The patient carrying the novel splicing mutation had a clinical history of encephalopathy related to status epilepticus during slow sleep (ESES), recently reported in another WAC individual. This first report of a WAC somatic mosaic remarks the contribution of mosaicism in the etiology of neurodevelopmental and neuropsychiatric disorders. We summarized the clinical data of reported individuals with WAC pathogenic mutations, which together with our findings, allowed for the expansion of the phenotypic spectrum of WAC-related disorders.
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Ionotropic Glutamate Receptors in Epilepsy: A Review Focusing on AMPA and NMDA Receptors. Biomolecules 2020; 10:biom10030464. [PMID: 32197322 PMCID: PMC7175173 DOI: 10.3390/biom10030464] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/13/2020] [Accepted: 03/14/2020] [Indexed: 12/22/2022] Open
Abstract
It is widely accepted that glutamate-mediated neuronal hyperexcitation plays a causative role in eliciting seizures. Among glutamate receptors, the roles of N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors in physiological and pathological conditions represent major clinical research targets. It is well known that agonists of NMDA or AMPA receptors can elicit seizures in animal or human subjects, while antagonists have been shown to inhibit seizures in animal models, suggesting a potential role for NMDA and AMPA receptor antagonists in anti-seizure drug development. Several such drugs have been evaluated in clinical studies; however, the majority, mainly NMDA-receptor antagonists, failed to demonstrate adequate efficacy and safety for therapeutic use, and only an AMPA-receptor antagonist, perampanel, has been approved for the treatment of some forms of epilepsy. These results suggest that a misunderstanding of the role of each glutamate receptor in the ictogenic process may underlie the failure of these drugs to demonstrate clinical efficacy and safety. Accumulating knowledge of both NMDA and AMPA receptors, including pathological gene mutations, roles in autoimmune epilepsy, and evidence from drug-discovery research and pharmacological studies, may provide valuable information enabling the roles of both receptors in ictogenesis to be reconsidered. This review aimed to integrate information from several studies in order to further elucidate the specific roles of NMDA and AMPA receptors in epilepsy.
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15
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The efficacy of perampanel in young children with drug-resistant epilepsy. Seizure 2020; 75:82-86. [DOI: 10.1016/j.seizure.2019.12.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 12/21/2019] [Accepted: 12/22/2019] [Indexed: 02/07/2023] Open
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16
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Recent advances in treatment of epilepsy-related sodium channelopathies. Eur J Paediatr Neurol 2020; 24:123-128. [PMID: 31889633 DOI: 10.1016/j.ejpn.2019.12.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 12/06/2019] [Indexed: 11/22/2022]
Abstract
Voltage-gated sodium channels (VGSCs) play a crucial role in generation of action potentials. Pathogenic variants in the five human brain expressed VGSC genes, SCN1A, SCN2A, SCN3A, SCN8A and SCN1B have been associated with a spectrum of epilepsy phenotypes and neurodevelopmental disorders. In the last decade, next generation sequencing techniques have revolutionized the way we diagnose these channelopathies, which is paving the way towards precision medicine. Knowing the functional effect (Loss-of-function versus Gain-of-function) of a variant is not only important for understanding the underlying pathophysiology, but it is particularly crucial to orient therapeutic decisions. Here we provide a review of the literature dealing with treatment options in epilepsy-related sodium channelopathies, including the current and emerging medications.
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17
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Mctague A. Navigating the genetic landscape of childhood epilepsy: a new perspective? Dev Med Child Neurol 2019; 61:858-859. [PMID: 30854642 DOI: 10.1111/dmcn.14203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Amy Mctague
- Molecular Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
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18
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Mele M, Costa RO, Duarte CB. Alterations in GABA A-Receptor Trafficking and Synaptic Dysfunction in Brain Disorders. Front Cell Neurosci 2019; 13:77. [PMID: 30899215 PMCID: PMC6416223 DOI: 10.3389/fncel.2019.00077] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/15/2019] [Indexed: 12/12/2022] Open
Abstract
GABAA receptors (GABAAR) are the major players in fast inhibitory neurotransmission in the central nervous system (CNS). Regulation of GABAAR trafficking and the control of their surface expression play important roles in the modulation of the strength of synaptic inhibition. Different pieces of evidence show that alterations in the surface distribution of GABAAR and dysregulation of their turnover impair the activity of inhibitory synapses. A diminished efficacy of inhibitory neurotransmission affects the excitatory/inhibitory balance and is a common feature of various disorders of the CNS characterized by an increased excitability of neuronal networks. The synaptic pool of GABAAR is mainly controlled through regulation of internalization, recycling and lateral diffusion of the receptors. Under physiological condition these mechanisms are finely coordinated to define the strength of GABAergic synapses. In this review article, we focus on the alteration in GABAAR trafficking with an impact on the function of inhibitory synapses in various disorders of the CNS. In particular we discuss how similar molecular mechanisms affecting the synaptic distribution of GABAAR and consequently the excitatory/inhibitory balance may be associated with a wide diversity of pathologies of the CNS, from psychiatric disorders to acute alterations leading to neuronal death. A better understanding of the cellular and molecular mechanisms that contribute to the impairment of GABAergic neurotransmission in these disorders, in particular the alterations in GABAAR trafficking and surface distribution, may lead to the identification of new pharmacological targets and to the development of novel therapeutic strategies.
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Affiliation(s)
- Miranda Mele
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Rui O Costa
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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