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Pineau L, Burnashev N. Functional Analysis of NMDAR Subunit Components in Postsynaptic Currents of Identified Cells and Synapses in Brain Slices. Methods Mol Biol 2024; 2799:139-150. [PMID: 38727906 DOI: 10.1007/978-1-0716-3830-9_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Epilepsy is one of the most represented neurological diseases worldwide. However, in many cases, the precise molecular mechanisms of epileptogenesis and ictiogenesis are unknown. Because of their important role in synaptic function and neuronal excitability, NMDA receptors are implicated in various epileptogenic mechanisms. Most of these are subunit specific and require a precise analysis of the subunit composition of the NMDARs implicated. Here, we describe an express electrophysiological method to analyze the contribution of NMDAR subunits to spontaneous postsynaptic activity in identified cells in brain slices using patch clamp whole cell recordings.
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Affiliation(s)
- Louison Pineau
- Mediterranean Institute of Neurobiology (INMED), INSERM, Aix-Marseille University, Marseille, France
| | - Nail Burnashev
- Mediterranean Institute of Neurobiology (INMED), INSERM, Aix-Marseille University, Marseille, France.
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El Mouhi H, Abbassi M, Sayel H, Trhanint S, Natiq A, El Hejjioui B, Jalte M, Ahmadi Y, Chaouki S. Autosomal Dominant Intellectual Development Disorder-6 (MRD6) Without Seizures Linked to a De Novo Mutation in the grin2b Gene Revealed by Exome Sequencing: A Case Report of a Moroccan Child. Cureus 2023; 15:e46456. [PMID: 37927744 PMCID: PMC10623208 DOI: 10.7759/cureus.46456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2023] [Indexed: 11/07/2023] Open
Abstract
Autosomal dominant intellectual development disorder-6 (MRD6) arises from a grin2b gene mutation, inducing neurodevelopmental issues. The effects of MRD6 encompass cognitive disabilities, seizures, muscle tone decline, and autism-like traits. Its severity ranges from mild impairment to severe epilepsy. The disorder's rarity is emphasized by roughly 100 reported GRIN2B-related cases, spotlighting the gene's significance in brain development. We present the case of a three-year-old Moroccan boy who was referred to a neuropediatric department for a molecular diagnosis. Initial genetic testing yielded inconclusive results, and subsequent tests for Angelman syndrome and metabolic diseases showed no abnormalities. Given the complexity of the disorder, exome sequencing was employed to identify the underlying genetic cause. Exome sequencing identified a nonsense (STOP) mutation c.3912C>G (p.Tyr1304Ter) in the grin2b gene in the heterozygous state known to be present in MRD6 (Online Mendelian Inheritance in Man (OMIM) 613970). The family segregation study shows that this is a de novo variant, which is confirmed by Sanger sequencing. This variant has not been previously reported in the GnomAD database. Based on current scientific knowledge, the variant is considered pathogenic (PVS1, PS2, PM2, PP3, PP5) according to the criteria of the American College of Medical Genetics and Genomics (ACMG). The mutation in the grin2b gene (p.Tyr1304Ter) was predicted to be deleterious through bioinformatics analysis tools. This study highlights the crucial role of the grin2b gene in normal brain development and communication within the nervous system. It also sheds light on the impact of a novel genetic mutation, identified through exome sequencing, on causing an intellectual developmental disorder in a child patient from Morocco.
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Affiliation(s)
- Hinde El Mouhi
- Laboratory of Biomedical and Translational Research, Faculty of Medicine and Pharmacy and Dental Medicine, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Center for Doctoral Studies Engineering Sciences and Techniques, Faculty of Sciences and Technologies, Sidi Mohammed Ben Abdellah University, Fez, MAR
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Meriame Abbassi
- Laboratory of Biomedical and Translational Research, Faculty of Medicine and Pharmacy and Dental Medicine, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Hanane Sayel
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Said Trhanint
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Abdelhafid Natiq
- Department of Genetics, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat, MAR
| | - Brahim El Hejjioui
- Laboratory of Biomedical and Translational Research, Faculty of Medicine and Pharmacy and Dental Medicine, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Merym Jalte
- Laboratory of Biotechnology, Environment, Agri-food, and Health (LBEAH), Faculty of Sciences Dhar El Mahraz, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Youssef Ahmadi
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Sana Chaouki
- Laboratory of Biomedical and Translational Research, Faculty of Medicine and Pharmacy and Dental Medicine, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Department of Pediatrics, Centre Hospitalier Universitaire (CHU) Hassan II, FEZ, MAR
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Vavers E, Zvejniece L, Dambrova M. Sigma-1 receptor and seizures. Pharmacol Res 2023; 191:106771. [PMID: 37068533 PMCID: PMC10176040 DOI: 10.1016/j.phrs.2023.106771] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 04/03/2023] [Accepted: 04/13/2023] [Indexed: 04/19/2023]
Abstract
Over the last decade, sigma-1 receptor (Sig1R) has been recognized as a valid target for the treatment of seizure disorders and seizure-related comorbidities. Clinical trials with Sig1R ligands are underway testing therapies for the treatment of drug-resistant seizures, developmental and epileptic encephalopathies, and photosensitive epilepsy. However, the direct molecular mechanism by which Sig1R modulates seizures and the balance between excitatory and inhibitory pathways has not been fully elucidated. This review article aims to summarize existing knowledge of Sig1R and its involvement in seizures by focusing on the evidence obtained from Sig1R knockout animals and the anti-seizure effects of Sig1R ligands. In addition, this review article includes a discussion of the advantages and disadvantages of the use of existing compounds and describes the challenges and future perspectives on the use of Sig1R as a target for the treatment of seizure disorders.
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Affiliation(s)
- Edijs Vavers
- Latvian Institute of Organic Synthesis, Laboratory of Pharmaceutical Pharmacology, Aizkraukles 21, LV-1006, Riga, Latvia; University of Tartu, Faculty of Science and Technology, Institute of Chemistry, Ravila 14a, 50411, Tartu, Estonia.
| | - Liga Zvejniece
- Latvian Institute of Organic Synthesis, Laboratory of Pharmaceutical Pharmacology, Aizkraukles 21, LV-1006, Riga, Latvia
| | - Maija Dambrova
- Latvian Institute of Organic Synthesis, Laboratory of Pharmaceutical Pharmacology, Aizkraukles 21, LV-1006, Riga, Latvia; Riga Stradiņš University, Faculty of Pharmacy, Konsula 21, LV-1007, Riga, Latvia
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Sivakumar S, Ghasemi M, Schachter SC. Targeting NMDA Receptor Complex in Management of Epilepsy. Pharmaceuticals (Basel) 2022; 15:ph15101297. [PMID: 36297409 PMCID: PMC9609646 DOI: 10.3390/ph15101297] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 11/05/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) are widely distributed in the central nervous system (CNS) and play critical roles in neuronal excitability in the CNS. Both clinical and preclinical studies have revealed that the abnormal expression or function of these receptors can underlie the pathophysiology of seizure disorders and epilepsy. Accordingly, NMDAR modulators have been shown to exert anticonvulsive effects in various preclinical models of seizures, as well as in patients with epilepsy. In this review, we provide an update on the pathologic role of NMDARs in epilepsy and an overview of the NMDAR antagonists that have been evaluated as anticonvulsive agents in clinical studies, as well as in preclinical seizure models.
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Affiliation(s)
- Shravan Sivakumar
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Mehdi Ghasemi
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
- Correspondence: (M.G.); (S.C.S.)
| | - Steven C. Schachter
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
- Harvard Medical School, Boston, MA 02114, USA
- Consortia for Improving Medicine with Innovation & Technology (CIMIT), Boston, MA 02114, USA
- Correspondence: (M.G.); (S.C.S.)
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Haddow K, Kind PC, Hardingham GE. NMDA Receptor C-Terminal Domain Signalling in Development, Maturity, and Disease. Int J Mol Sci 2022; 23:ijms231911392. [PMID: 36232696 PMCID: PMC9570437 DOI: 10.3390/ijms231911392] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 11/18/2022] Open
Abstract
The NMDA receptor is a Ca2+-permeant glutamate receptor which plays key roles in health and disease. Canonical NMDARs contain two GluN2 subunits, of which 2A and 2B are predominant in the forebrain. Moreover, the relative contribution of 2A vs. 2B is controlled both developmentally and in an activity-dependent manner. The GluN2 subtype influences the biophysical properties of the receptor through difference in their N-terminal extracellular domain and transmembrane regions, but they also have large cytoplasmic Carboxyl (C)-terminal domains (CTDs) which have diverged substantially during evolution. While the CTD identity does not influence NMDAR subunit specific channel properties, it determines the nature of CTD-associated signalling molecules and has been implicated in mediating the control of subunit composition (2A vs. 2B) at the synapse. Historically, much of the research into the differential function of GluN2 CTDs has been conducted in vitro by over-expressing mutant subunits, but more recently, the generation of knock-in (KI) mouse models have allowed CTD function to be probed in vivo and in ex vivo systems without heterologous expression of GluN2 mutants. In some instances, findings involving KI mice have been in disagreement with models that were proposed based on earlier approaches. This review will examine the current research with the aim of addressing these controversies and how methodology may contribute to differences between studies. We will also discuss the outstanding questions regarding the role of GluN2 CTD sequences in regulating NMDAR subunit composition, as well as their relevance to neurodegenerative disease and neurodevelopmental disorders.
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Affiliation(s)
- Kirsty Haddow
- UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Chancellor’s Building, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Peter C. Kind
- UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Chancellor’s Building, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Giles E. Hardingham
- UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Chancellor’s Building, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Correspondence:
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