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Nelson AD, Catalfio AM, Gupta JP, Min L, Caballero-Florán RN, Dean KP, Elvira CC, Derderian KD, Kyoung H, Sahagun A, Sanders SJ, Bender KJ, Jenkins PM. Physical and functional convergence of the autism risk genes Scn2a and Ank2 in neocortical pyramidal cell dendrites. Neuron 2024; 112:1133-1149.e6. [PMID: 38290518 DOI: 10.1016/j.neuron.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 04/26/2023] [Accepted: 01/03/2024] [Indexed: 02/01/2024]
Abstract
Dysfunction in sodium channels and their ankyrin scaffolding partners have both been implicated in neurodevelopmental disorders, including autism spectrum disorder (ASD). In particular, the genes SCN2A, which encodes the sodium channel NaV1.2, and ANK2, which encodes ankyrin-B, have strong ASD association. Recent studies indicate that ASD-associated haploinsufficiency in Scn2a impairs dendritic excitability and synaptic function in neocortical pyramidal cells, but how NaV1.2 is anchored within dendritic regions is unknown. Here, we show that ankyrin-B is essential for scaffolding NaV1.2 to the dendritic membrane of mouse neocortical neurons and that haploinsufficiency of Ank2 phenocopies intrinsic dendritic excitability and synaptic deficits observed in Scn2a+/- conditions. These results establish a direct, convergent link between two major ASD risk genes and reinforce an emerging framework suggesting that neocortical pyramidal cell dendritic dysfunction can contribute to neurodevelopmental disorder pathophysiology.
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Affiliation(s)
- Andrew D Nelson
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Amanda M Catalfio
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Julie P Gupta
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Lia Min
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Kendall P Dean
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Carina C Elvira
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kimberly D Derderian
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Henry Kyoung
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Atehsa Sahagun
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Stephan J Sanders
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA, USA
| | - Kevin J Bender
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA.
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2
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Ovchinnikov DA, Jong S, Cuddy C, Dalby K, Devinsky O, Mullen S, Maljevic S, Petrou S. An iPSC line (FINi003-A) from a male with late-onset developmental and epileptic encephalopathy caused by a heterozygous p.E1211K variant in the SCN2A gene encoding the voltage-gated sodium channel Na v1.2. Stem Cell Res 2024; 76:103367. [PMID: 38479087 DOI: 10.1016/j.scr.2024.103367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/06/2024] [Accepted: 02/25/2024] [Indexed: 03/25/2024] Open
Abstract
Many developmental and epileptic encephalopathies (DEEs) result from variants in cation channel genes. Using mRNA transfection, we generated and characterised an induced pluripotent stem cell (iPSC) line from the fibroblasts of a male late-onset DEE patient carrying a heterozygous missense variant (E1211K) in Nav1.2(SCN2A) protein. The iPSC line displays features characteristic of the human iPSCs, colony morphology and expression of pluripotency-associated marker genes, ability to produce derivatives of all three embryonic germ layers, and normal karyotype without SNP array-detectable abnormalities. We anticipate that this iPSC line will aid in the modelling and development of precision therapies for this debilitating condition.
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Affiliation(s)
- Dmitry A Ovchinnikov
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC, Australia
| | - Sharon Jong
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC, Australia
| | - Claire Cuddy
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC, Australia
| | - Kelly Dalby
- Praxis Precision Medicines, Cambridge, MA, USA
| | - Orrin Devinsky
- Department of Neurology, NYU Grossman School of Medicine, New York, NY, USA
| | - Saul Mullen
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC, Australia; Departments of Medicine and Paediatrics, The University of Melbourne, Austin Health and Royal Children's Hospital, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Snezana Maljevic
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC, Australia.
| | - Steve Petrou
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC, Australia; Praxis Precision Medicines, Cambridge, MA, USA.
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3
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Mao M, Mattei C, Rollo B, Byars S, Cuddy C, Berecki G, Heighway J, Pachernegg S, Menheniott T, Apted D, Jia L, Dalby K, Nemiroff A, Mullen S, Reid CA, Maljevic S, Petrou S. Distinctive In Vitro Phenotypes in iPSC-Derived Neurons From Patients With Gain- and Loss-of-Function SCN2A Developmental and Epileptic Encephalopathy. J Neurosci 2024; 44:e0692232023. [PMID: 38148154 PMCID: PMC10883610 DOI: 10.1523/jneurosci.0692-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 12/28/2023] Open
Abstract
SCN2A encodes NaV1.2, an excitatory neuron voltage-gated sodium channel and a major monogenic cause of neurodevelopmental disorders, including developmental and epileptic encephalopathies (DEE) and autism. Clinical presentation and pharmocosensitivity vary with the nature of SCN2A variant dysfunction and can be divided into gain-of-function (GoF) cases with pre- or peri-natal seizures and loss-of-function (LoF) patients typically having infantile spasms after 6 months of age. We established and assessed patient induced pluripotent stem cell (iPSC) - derived neuronal models for two recurrent SCN2A DEE variants with GoF R1882Q and LoF R853Q associated with early- and late-onset DEE, respectively. Two male patient-derived iPSC isogenic pairs were differentiated using Neurogenin-2 overexpression yielding populations of cortical-like glutamatergic neurons. Functional properties were assessed using patch clamp and multielectrode array recordings and transcriptomic profiles obtained with total mRNA sequencing after 2-4 weeks in culture. At 3 weeks of differentiation, increased neuronal activity at cellular and network levels was observed for R1882Q iPSC-derived neurons. In contrast, R853Q neurons showed only subtle changes in excitability after 4 weeks and an overall reduced network activity after 7 weeks in vitro. Consistent with the reported efficacy in some GoF SCN2A patients, phenytoin (sodium channel blocker) reduced the excitability of neurons to the control levels in R1882Q neuronal cultures. Transcriptomic alterations in neurons were detected for each variant and convergent pathways suggested potential shared mechanisms underlying SCN2A DEE. In summary, patient iPSC-derived neuronal models of SCN2A GoF and LoF pathogenic variants causing DEE show specific functional and transcriptomic in vitro phenotypes.
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Affiliation(s)
- Miaomiao Mao
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Cristiana Mattei
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Ben Rollo
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria 3800, Australia
| | - Sean Byars
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Claire Cuddy
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Geza Berecki
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Jacqueline Heighway
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Svenja Pachernegg
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria 3052, Australia
| | - Trevelyan Menheniott
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria 3052, Australia
| | - Danielle Apted
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Linghan Jia
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Kelley Dalby
- Rogcon Biosciences, Cambridge, MA 02142
- Praxis Precision Medicines, Inc., Cambridge, MA 02142
| | - Alex Nemiroff
- Rogcon Biosciences, Cambridge, MA 02142
- Praxis Precision Medicines, Inc., Cambridge, MA 02142
| | - Saul Mullen
- Austin Health, University of Melbourne, Melbourne, Victoria 3084, Australia
| | - Christopher A Reid
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Snezana Maljevic
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
- Praxis Precision Medicines, Inc., Cambridge, MA 02142
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Panagiotakaki E, Tiziano FD, Mikati MA, Vijfhuizen LS, Nicole S, Lesca G, Abiusi E, Novelli A, Di Pietro L, Harder AVE, Walley NM, De Grandis E, Poulat AL, Portes VD, Lépine A, Nassogne MC, Arzimanoglou A, Vavassori R, Koenderink J, Thompson CH, George AL, Gurrieri F, van den Maagdenberg AMJM, Heinzen EL. Exome sequencing of ATP1A3-negative cases of alternating hemiplegia of childhood reveals SCN2A as a novel causative gene. Eur J Hum Genet 2024; 32:224-231. [PMID: 38097767 PMCID: PMC10853263 DOI: 10.1038/s41431-023-01489-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/25/2023] [Accepted: 10/18/2023] [Indexed: 02/10/2024] Open
Abstract
Alternating hemiplegia of childhood (AHC) is a rare neurodevelopment disorder that is typically characterized by debilitating episodic attacks of hemiplegia, seizures, and intellectual disability. Over 85% of individuals with AHC have a de novo missense variant in ATP1A3 encoding the catalytic α3 subunit of neuronal Na+/K+ ATPases. The remainder of the patients are genetically unexplained. Here, we used next-generation sequencing to search for the genetic cause of 26 ATP1A3-negative index patients with a clinical presentation of AHC or an AHC-like phenotype. Three patients had affected siblings. Using targeted sequencing of exonic, intronic, and flanking regions of ATP1A3 in 22 of the 26 index patients, we found no ultra-rare variants. Using exome sequencing, we identified the likely genetic diagnosis in 9 probands (35%) in five genes, including RHOBTB2 (n = 3), ATP1A2 (n = 3), ANK3 (n = 1), SCN2A (n = 1), and CHD2 (n = 1). In follow-up investigations, two additional ATP1A3-negative individuals were found to have rare missense SCN2A variants, including one de novo likely pathogenic variant and one likely pathogenic variant for which inheritance could not be determined. Functional evaluation of the variants identified in SCN2A and ATP1A2 supports the pathogenicity of the identified variants. Our data show that genetic variants in various neurodevelopmental genes, including SCN2A, lead to AHC or AHC-like presentation. Still, the majority of ATP1A3-negative AHC or AHC-like patients remain unexplained, suggesting that other mutational mechanisms may account for the phenotype or that cases may be explained by oligo- or polygenic risk factors.
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Affiliation(s)
- Eleni Panagiotakaki
- Department of Paediatric Clinical Epileptology, Sleep Disorders and Functional Neurology, Member of the ERN EpiCare, University Hospitals of Lyon (HCL), Lyon, France
| | - Francesco D Tiziano
- Institute of Genomic Medicine, Catholic University and Policlinico Gemelli, Fondazione Policlinico Universitario Agostino Gemelli IRCSS, Rome, Italy
| | - Mohamad A Mikati
- Division of Pediatric Neurology and Developmental Medicine, Duke University, Durham, NC, USA
| | - Lisanne S Vijfhuizen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Sophie Nicole
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Gaetan Lesca
- Department of Medical Genetics, University Hospital of Lyon and Claude Bernard Lyon I University, Lyon France - Pathophysiology and Genetics of Neuron and Muscle (PNMG), UCBL, CNRS UMR5261 - INSERM U1315, Lyon, France
| | - Emanuela Abiusi
- Department of Life Sciences and Public Health, Section of Genomic Medicine, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Agnese Novelli
- Department of Life Sciences and Public Health, Section of Genomic Medicine, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Lorena Di Pietro
- Institute of Genomic Medicine, Catholic University and Policlinico Gemelli, Fondazione Policlinico Universitario Agostino Gemelli IRCSS, Rome, Italy
- Department of Life Sciences and Public Health, Section of Genomic Medicine, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Aster V E Harder
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Nicole M Walley
- Department of Pediatrics, Division of Medical Genetics, Duke Health, Durham, NC, USA
| | - Elisa De Grandis
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
- Child Neuropsychiatry Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Anne-Lise Poulat
- Pediatric Neurology Department, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL), Lyon, France
| | - Vincent Des Portes
- Pediatric Neurology Department, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL), Lyon, France
| | - Anne Lépine
- Service de neuropédiatrie, Centre hospitalo universitaire de la Timone, Marseille, France
| | - Marie-Cecile Nassogne
- Institut des Maladies Rares, Cliniques Universitaires Saint-Luc, UCLouvain, Brussels, Belgium
- Service de Neurologie Pédiatrique, Member of the ERN MetabERN, Cliniques Universitaires Saint-Luc, UCLouvain, Brussels, Belgium
| | - Alexis Arzimanoglou
- Department of Paediatric Clinical Epileptology, Sleep Disorders and Functional Neurology, Member of the ERN EpiCare, University Hospitals of Lyon (HCL), Lyon, France
- Department of Child Neurology and Epilepsy Research Unit, Member of the ERN EpiCARE, Hospital San Juan de Dios, Barcelona, Spain
| | - Rosaria Vavassori
- Euro-Mediterranean Institute for Science and Technology I.E.ME.S.T., Palermo, Italy
| | - Jan Koenderink
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Fiorella Gurrieri
- Department of Medicine, Research Unit of Medical Genetics, Università Campus Bio-Medico di Roma, Roma, Italy
- Operative Research Unit of Medical Genetics Fondazione Policlinico Universitario Campus Bio-Medico, Roma, Italy
| | - Arn M J M van den Maagdenberg
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Erin L Heinzen
- Division of Pharmacology and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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5
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Schamiloglu S, Wu H, Zhou M, Kwan AC, Bender KJ. Dynamic Foraging Behavior Performance Is Not Affected by Scn2a Haploinsufficiency. eNeuro 2023; 10:ENEURO.0367-23.2023. [PMID: 38151324 PMCID: PMC10755640 DOI: 10.1523/eneuro.0367-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/23/2023] [Accepted: 11/14/2023] [Indexed: 12/29/2023] Open
Abstract
Dysfunction in the gene SCN2A, which encodes the voltage-gated sodium channel Nav1.2, is strongly associated with neurodevelopmental disorders including autism spectrum disorder and intellectual disability (ASD/ID). This dysfunction typically manifests in these disorders as a haploinsufficiency, where loss of one copy of a gene cannot be compensated for by the other allele. Scn2a haploinsufficiency affects a range of cells and circuits across the brain, including associative neocortical circuits that are important for cognitive flexibility and decision-making behaviors. Here, we tested whether Scn2a haploinsufficiency has any effect on a dynamic foraging task that engages such circuits. Scn2a +/- mice and wild-type (WT) littermates were trained on a choice behavior where the probability of reward between two options varied dynamically across trials and where the location of the high reward underwent uncued reversals. Despite impairments in Scn2a-related neuronal excitability, we found that both male and female Scn2a +/- mice performed these tasks as well as wild-type littermates, with no behavioral difference across genotypes in learning or performance parameters. Varying the number of trials between reversals or probabilities of receiving reward did not result in an observable behavioral difference, either. These data suggest that, despite heterozygous loss of Scn2a, mice can perform relatively complex foraging tasks that make use of higher-order neuronal circuits.
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Affiliation(s)
- Selin Schamiloglu
- Neuroscience Graduate Program, University of California, San Francisco, CA 94158
- Center for Integrative Neuroscience, Department of Neurology, University of California, San Francisco, CA 94158
| | - Hao Wu
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06511
| | - Mingkang Zhou
- Neuroscience Graduate Program, University of California, San Francisco, CA 94158
- Center for Integrative Neuroscience, Department of Neurology, University of California, San Francisco, CA 94158
| | - Alex C Kwan
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06511
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
| | - Kevin J Bender
- Center for Integrative Neuroscience, Department of Neurology, University of California, San Francisco, CA 94158
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Filippi C, Milito G, Accorsi P, Muda A, Fazzi EM, Martelli P, Riva A, Giordano L. Frequency of SCN2A-related disorder in the regional epilepsy centre of brescia between 2002 and 2021. Clin Neurol Neurosurg 2023; 234:107983. [PMID: 37776663 DOI: 10.1016/j.clineuro.2023.107983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 09/11/2023] [Accepted: 09/14/2023] [Indexed: 10/02/2023]
Abstract
OBJECTIVE SCN2A gene pathogenic variants are associated with a wide phenotypic spectrum, encompassing epilepsy, developmental delay, and autism spectrum disorder. Researches conducted in Denmark have revealed a disease frequency of approximately 1/78,608 (0.0012%) live births in this population. We estimated the frequency of SCN2A-related disorder in the birth cohort of Brescia and its province between 2002 and 2021. METHODS Frequency was calculated by ratio between patients with SCN2A pathogenic variant and the total number of live births at the Regional Epilepsy Center of Brescia, between 2002 and 2021. The number of births in Brescia and province was obtained from the Italian National Institute of Statistics (ISTAT). RESULTS A frequency of 11/23,2678 births (0.0047%) was found. In comparison with Danish data, we noticed a higher frequency of the pathogenic variant in our population, even considering the same time frame (0.0035% of subjects born between 2006 and 2014). CONCLUSION The frequency of SCN2A pathogenic variant among live births in Brescia and its Province between 2006 and 2014 was about three times that of Danish population; this difference was about four times if we consider the period from 2002 to 2021. More studies are needed to further delineate the frequency of SCN2A pathogenic variant in Italian population.
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Affiliation(s)
- Corinna Filippi
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
| | - Giuseppe Milito
- Regional Epilepsy Center, Operative Unit of Childhood and Adolescent Neuropsychiatry - ASST Spedali Civili di Brescia, Brescia, Italy
| | - Patrizia Accorsi
- Regional Epilepsy Center, Operative Unit of Childhood and Adolescent Neuropsychiatry - ASST Spedali Civili di Brescia, Brescia, Italy
| | - Alice Muda
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Elisa Maria Fazzi
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Paola Martelli
- Regional Epilepsy Center, Operative Unit of Childhood and Adolescent Neuropsychiatry - ASST Spedali Civili di Brescia, Brescia, Italy
| | - Antonella Riva
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Lucio Giordano
- Regional Epilepsy Center, Operative Unit of Childhood and Adolescent Neuropsychiatry - ASST Spedali Civili di Brescia, Brescia, Italy
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7
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Thompson CH, Potet F, Abramova TV, DeKeyser JM, Ghabra NF, Vanoye CG, Millichap JJ, George AL. Epilepsy-associated SCN2A (NaV1.2) variants exhibit diverse and complex functional properties. J Gen Physiol 2023; 155:e202313375. [PMID: 37578743 PMCID: PMC10424433 DOI: 10.1085/jgp.202313375] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 06/29/2023] [Accepted: 07/25/2023] [Indexed: 08/15/2023] Open
Abstract
Pathogenic variants in voltage-gated sodium (NaV) channel genes including SCN2A, encoding NaV1.2, are discovered frequently in neurodevelopmental disorders with or without epilepsy. SCN2A is also a high-confidence risk gene for autism spectrum disorder (ASD) and nonsyndromic intellectual disability (ID). Previous work to determine the functional consequences of SCN2A variants yielded a paradigm in which predominantly gain-of-function variants cause neonatal-onset epilepsy, whereas loss-of-function variants are associated with ASD and ID. However, this framework was derived from a limited number of studies conducted under heterogeneous experimental conditions, whereas most disease-associated SCN2A variants have not been functionally annotated. We determined the functional properties of SCN2A variants using automated patch-clamp recording to demonstrate the validity of this method and to examine whether a binary classification of variant dysfunction is evident in a larger cohort studied under uniform conditions. We studied 28 disease-associated variants and 4 common variants using two alternatively spliced isoforms of NaV1.2 expressed in HEK293T cells. Automated patch-clamp recording provided a valid high throughput method to ascertain detailed functional properties of NaV1.2 variants with concordant findings for variants that were previously studied using manual patch clamp. Many epilepsy-associated variants in our study exhibited complex patterns of gain- and loss-of-functions that are difficult to classify by a simple binary scheme. The higher throughput achievable with automated patch clamp enables study of variants with greater standardization of recording conditions, freedom from operator bias, and enhanced experimental rigor. This approach offers an enhanced ability to discern relationships between channel dysfunction and neurodevelopmental disorders.
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Affiliation(s)
- Christopher H. Thompson
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Franck Potet
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Tatiana V. Abramova
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jean-Marc DeKeyser
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Nora F. Ghabra
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Carlos G. Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - John J. Millichap
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Alfred L. George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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8
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Ovchinnikov DA, Jong S, Cuddy C, Scheffer IE, Maljevic S, Petrou S. Generation of an iPSC line (FINi001-A) from a girl with developmental and epileptic encephalopathy due to a heterozygous gain-of-function p.R1882Q variant in the voltage-gated sodium channel Na v1.2 protein encoded by the SCN2A gene. Stem Cell Res 2023; 71:103179. [PMID: 37597357 DOI: 10.1016/j.scr.2023.103179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/02/2023] [Accepted: 08/06/2023] [Indexed: 08/21/2023] Open
Abstract
A range of epilepsies, including the most severe group of developmental and epileptic encephalopathies (DEEs), are caused by gain-of-function variants in voltage-gated channels. Here we report the generation and characterisation of an iPSC cell line from the fibroblasts of a girl with early infantile DEE carrying heterozygous missense gain-of-function mutation (R1882Q) in Nav1.2(SCN2A) protein, using transient transfection with a single mRNA molecule. The established iPSC line displays typical human primed pluripotent stem cell characteristics: typical colony morphology and robust expression of pluripotency-associated marker genes, ability to give rise to derivatives of all three embryonic germ layers, and normal karyotype without any SNP array-detectable copy number variations. We anticipate that this iPSC line will be useful for the development of neuronal hyperactivity-caused human stem cell-based DEE models, advancing both understanding and potential therapy development for this debilitating condition.
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Affiliation(s)
- D A Ovchinnikov
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC Australia
| | - S Jong
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC Australia
| | - C Cuddy
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC Australia
| | - I E Scheffer
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC Australia; Departments of Medicine and Paediatrics, The University of Melbourne, Austin Health and Royal Children's Hospital, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - S Maljevic
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC Australia
| | - S Petrou
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne 3010 VIC Australia; Praxis Precision Medicines, Cambridge, MA, USA.
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9
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Asadollahi R, Delvendahl I, Muff R, Tan G, Rodríguez DG, Turan S, Russo M, Oneda B, Joset P, Boonsawat P, Masood R, Mocera M, Ivanovski I, Baumer A, Bachmann-Gagescu R, Schlapbach R, Rehrauer H, Steindl K, Begemann A, Reis A, Winkler J, Winner B, Müller M, Rauch A. Pathogenic SCN2A variants cause early-stage dysfunction in patient-derived neurons. Hum Mol Genet 2023; 32:2192-2204. [PMID: 37010102 PMCID: PMC10281746 DOI: 10.1093/hmg/ddad048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/23/2023] [Accepted: 03/19/2023] [Indexed: 04/04/2023] Open
Abstract
Pathogenic heterozygous variants in SCN2A, which encodes the neuronal sodium channel NaV1.2, cause different types of epilepsy or intellectual disability (ID)/autism without seizures. Previous studies using mouse models or heterologous systems suggest that NaV1.2 channel gain-of-function typically causes epilepsy, whereas loss-of-function leads to ID/autism. How altered channel biophysics translate into patient neurons remains unknown. Here, we investigated iPSC-derived early-stage cortical neurons from ID patients harboring diverse pathogenic SCN2A variants [p.(Leu611Valfs*35); p.(Arg937Cys); p.(Trp1716*)] and compared them with neurons from an epileptic encephalopathy (EE) patient [p.(Glu1803Gly)] and controls. ID neurons consistently expressed lower NaV1.2 protein levels. In neurons with the frameshift variant, NaV1.2 mRNA and protein levels were reduced by ~ 50%, suggesting nonsense-mediated decay and haploinsufficiency. In other ID neurons, only protein levels were reduced implying NaV1.2 instability. Electrophysiological analysis revealed decreased sodium current density and impaired action potential (AP) firing in ID neurons, consistent with reduced NaV1.2 levels. In contrast, epilepsy neurons displayed no change in NaV1.2 levels or sodium current density, but impaired sodium channel inactivation. Single-cell transcriptomics identified dysregulation of distinct molecular pathways including inhibition of oxidative phosphorylation in neurons with SCN2A haploinsufficiency and activation of calcium signaling and neurotransmission in epilepsy neurons. Together, our patient iPSC-derived neurons reveal characteristic sodium channel dysfunction consistent with biophysical changes previously observed in heterologous systems. Additionally, our model links the channel dysfunction in ID to reduced NaV1.2 levels and uncovers impaired AP firing in early-stage neurons. The altered molecular pathways may reflect a homeostatic response to NaV1.2 dysfunction and can guide further investigations.
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Affiliation(s)
- R Asadollahi
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
- Faculty of Engineering and Science, University of Greenwich London, Medway Campus, Chatham Maritime ME4 4TB, UK
| | - I Delvendahl
- Department of Molecular Life Sciences, University of Zurich, Zurich 8057, Switzerland
- Neuroscience Center Zurich, University of Zurich, Zurich 8057, Switzerland
| | - R Muff
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - G Tan
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich 8057, Switzerland
| | - D G Rodríguez
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich 8057, Switzerland
| | - S Turan
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany
| | - M Russo
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - B Oneda
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - P Joset
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - P Boonsawat
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - R Masood
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - M Mocera
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - I Ivanovski
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - A Baumer
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - R Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - R Schlapbach
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich 8057, Switzerland
| | - H Rehrauer
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich 8057, Switzerland
| | - K Steindl
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - A Begemann
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
| | - A Reis
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany
| | - J Winkler
- Department of Molecular Neurology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany
- Center for Rare Diseases Erlangen, University Hospital Erlangen, Erlangen 91054, Germany
| | - B Winner
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany
- Center for Rare Diseases Erlangen, University Hospital Erlangen, Erlangen 91054, Germany
| | - M Müller
- Department of Molecular Life Sciences, University of Zurich, Zurich 8057, Switzerland
- Neuroscience Center Zurich, University of Zurich, Zurich 8057, Switzerland
- University of Zurich Clinical Research Priority Program (CRPP) Praeclare – Personalized prenatal and reproductive medicine, Zurich 8006, Switzerland
- University of Zurich Research Priority Program (URPP) AdaBD: Adaptive Brain Circuits in Development and Learning, Zurich 8006, Switzerland
| | - A Rauch
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich 8952, Switzerland
- Neuroscience Center Zurich, University of Zurich, Zurich 8057, Switzerland
- University of Zurich Clinical Research Priority Program (CRPP) Praeclare – Personalized prenatal and reproductive medicine, Zurich 8006, Switzerland
- University of Zurich Research Priority Program (URPP) AdaBD: Adaptive Brain Circuits in Development and Learning, Zurich 8006, Switzerland
- University of Zurich Research Priority Program (URPP) ITINERARE: Innovative Therapies in Rare Diseases, Zurich 8006, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich 8057, Switzerland
- University Children's Hospital Zurich, University of Zurich, Zurich 8032, Switzerland
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10
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Ma Z, Eaton M, Liu Y, Zhang J, Chen X, Tu X, Shi Y, Que Z, Wettschurack K, Zhang Z, Shi R, Chen Y, Kimbrough A, Lanman NA, Schust L, Huang Z, Yang Y. Deficiency of autism-related Scn2a gene in mice disrupts sleep patterns and circadian rhythms. Neurobiol Dis 2022; 168:105690. [PMID: 35301122 PMCID: PMC9018617 DOI: 10.1016/j.nbd.2022.105690] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 02/21/2022] [Accepted: 03/09/2022] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorder (ASD) affects ~2% of the population in the US, and monogenic forms of ASD often result in the most severe manifestation of the disorder. Recently, SCN2A has emerged as a leading gene associated with ASD, of which abnormal sleep pattern is a common comorbidity. SCN2A encodes the voltage-gated sodium channel NaV1.2. Predominantly expressed in the brain, NaV1.2 mediates the action potential firing of neurons. Clinical studies found that a large portion of children with SCN2A deficiency have sleep disorders, which severely impact the quality of life of affected individuals and their caregivers. The underlying mechanism of sleep disturbances related to NaV1.2 deficiency, however, is not known. Using a gene-trap Scn2a-deficient mouse model (Scn2atrap), we found that Scn2a deficiency results in increased wakefulness and reduced non-rapid-eye-movement (NREM) sleep. Brain region-specific Scn2a deficiency in the suprachiasmatic nucleus (SCN) containing region, which is involved in circadian rhythms, partially recapitulates the sleep disturbance phenotypes. At the cellular level, we found that Scn2a deficiency disrupted the firing pattern of spontaneously firing neurons in the SCN region. At the molecular level, RNA-sequencing analysis revealed differentially expressed genes in the circadian entrainment pathway including core clock genes Per1 and Per2. Performing a transcriptome-based compound discovery, we identified dexanabinol (HU-211), a putative glutamate receptor modulator, that can partially reverse the sleep disturbance in mice. Overall, our study reveals possible molecular and cellular mechanisms underlying Scn2a deficiency-related sleep disturbances, which may inform the development of potential pharmacogenetic interventions for the affected individuals.
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Affiliation(s)
- Zhixiong Ma
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China; Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Muriel Eaton
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Yushuang Liu
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Jingliang Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Xiaoling Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Xinyu Tu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yiqiang Shi
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Zhefu Que
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Kyle Wettschurack
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Zaiyang Zhang
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Riyi Shi
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Yueyi Chen
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Adam Kimbrough
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Nadia A Lanman
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Leah Schust
- FamilieSCN2A Foundation, P.O. Box 82, East Longmeadow, MA 01028, USA
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China.
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA.
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11
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Richardson R, Baralle D, Bennett C, Briggs T, Bijlsma EK, Clayton-Smith J, Constantinou P, Foulds N, Jarvis J, Jewell R, Johnson DS, McEntagart M, Parker MJ, Radley JA, Robertson L, Ruivenkamp C, Rutten JW, Tellez J, Turnpenny PD, Wilson V, Wright M, Balasubramanian M. Further delineation of phenotypic spectrum of SCN2A-related disorder. Am J Med Genet A 2022; 188:867-877. [PMID: 34894057 DOI: 10.1002/ajmg.a.62595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/28/2021] [Accepted: 11/20/2021] [Indexed: 01/12/2023]
Abstract
SCN2A-related disorders include intellectual disability, autism spectrum disorder, seizures, episodic ataxia, and schizophrenia. In this study, the phenotype-genotype association in SCN2A-related disorders was further delineated by collecting detailed clinical and molecular characteristics. Using previously proposed genotype-phenotype hypotheses based on variant function and position, the potential of phenotype prediction from the variants found was examined. Patients were identified through the Deciphering Developmental Disorders study and gene matching strategies. Phenotypic information and variant interpretation evidence were collated. Seventeen previously unreported patients and five patients who had been previously reported (but with minimal phenotypic and segregation data) were included (10 males, 12 females; median age 10.5 years). All patients had developmental delays and the majority had intellectual disabilities. Seizures were reported in 15 of 22 (68.2%), four of 22 (18.2%) had autism spectrum disorder and no patients were reported with episodic ataxia. The majority of variants were de novo. One family had presumed gonadal mosaicism. The correlation of the use of sodium channel-blocking antiepileptic drugs with phenotype or genotype was variable. These data suggest that variant type and position alone can provide some predictive information about the phenotype in a proportion of cases, but more precise assessment of variant function is needed for meaningful phenotype prediction.
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Affiliation(s)
- Ruth Richardson
- Northern Genetics Service, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle, UK
| | - Diana Baralle
- University Hospital of Southampton NHS Foundation Trust, Southampton, UK
- Faculty of Medicine, University of Southampton, Southampton, UK
| | - Christopher Bennett
- Yorkshire Regional Genetics Service, The Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Tracy Briggs
- NW Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Emilia K Bijlsma
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jill Clayton-Smith
- NW Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK
| | | | - Nicola Foulds
- University Hospital of Southampton NHS Foundation Trust, Southampton, UK
| | - Joanna Jarvis
- Clinical Genetics Unit, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - Rosalyn Jewell
- Yorkshire Regional Genetics Service, The Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Diana S Johnson
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Meriel McEntagart
- South West Thames Regional Genetics Centre, St. George's Healthcare NHS Trust, St. George's, University of London, London, UK
| | - Michael J Parker
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Jessica A Radley
- London North West Regional Genetics Service, St. Mark's and Northwick Park Hospitals, London, UK
| | | | - Claudia Ruivenkamp
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Julie W Rutten
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - James Tellez
- Northern Genetics Service, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle, UK
| | - Peter D Turnpenny
- Clinical Genetics Department, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Valerie Wilson
- Northern Genetics Service, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle, UK
| | - Michael Wright
- Northern Genetics Service, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle, UK
| | - Meena Balasubramanian
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
- Academic Unit of Child Health, Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
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12
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Guan J, Du KX, Dong Y, Li L, Song PP, Gong H, Zhang XL, Jia TM. [Clinical and genetic spectrum of SCN2A gene associated epilepsy and episodic ataxia]. Zhonghua Er Ke Za Zhi 2022; 60:51-55. [PMID: 34986624 DOI: 10.3760/cma.j.cn112140-20210610-00491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Objective: To explore the clinical manifestations and genetic characteristics of patients with epilepsy and episodic ataxia caused by SCN2A gene variation. Methods: The clinical data of seizure manifestation, imaging examination and genetic results of 5 patients with epilepsy and (or) episodic ataxia because of SCN2A gene variation admitted to the Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University from July 2017 to January 2021 were analyzed retrospectively. Results: Among 5 patients, 4 were female and 1 was male. The onset age of epilepsy ranged from 4 days to 8 months. There were 2 cases of benign neonatal or infantile epilepsy and 3 cases of epileptic encephalopathy, in whom 1 case had development retardation,1 case transformed from West syndrome to infantile spasm and another one transformed from infantile spasm to Lennox-Gastaut syndrome. One case of benign neonatal-infantile epilepsy was characterized by neonatal onset seizures and episodic ataxia developed at the age of 78 months. Electroencephalograms at first visit of 5 cases showed that 2 cases were normal, 1 case had focal epileptic discharge, and 2 cases had multi-focal abnormal discharge with peak arrhythmia. The brain magnetic resonance imaging (MRI) of 3 cases were nomal, 1 case was abnormal (brain atrophy with decreased white matter) and the results of 1 case was unknown. The follow-up time ranged from 17 months to 89 months. Four cases of epilepsy were controlled and 1 case died at 2 years of age. Two cases had normal intelligence and motor development, 2 had moderate to severe intelligence retardation and motor critical state, and 1 had moderate to severe intelligence and motor development retardation. SCN2A gene variations were identified in all cases. There were 4 missense variations and 1 frameshift variation. Three variations had not been reported so far, including c.4906A>G,c.3643G>T,c.638delT. Conclusions: Variations in SCN2A gene can cause benign neonatal or infantile epilepsy and epileptic encephalopathy. Some children develop episodic ataxia with growing age. The variation of SCN2A gene is mainly missense variation.
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Affiliation(s)
- J Guan
- Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450002, China
| | - K X Du
- Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450002, China
| | - Y Dong
- Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450002, China
| | - L Li
- Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450002, China
| | - P P Song
- Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450002, China
| | - H Gong
- Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450002, China
| | - X L Zhang
- Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450002, China
| | - T M Jia
- Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450002, China
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13
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Berseem NF, Khattab ESAEH, Saad DS, Abd Elnaby SA. Role of SCN2A c.56G/A Gene Polymorphism in Egyptian Children with Genetic Epilepsy with Febrile Seizure Plus. CNS Neurol Disord Drug Targets 2022; 21:450-457. [PMID: 34607551 DOI: 10.2174/1871527320666211004123731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/11/2020] [Accepted: 11/30/2020] [Indexed: 06/13/2023]
Abstract
BACKGROUND Febrile Seizures (FS) are the most common seizures in children younger than 5 years. In the last decade, various coding and noncoding sequence variations of voltage-gated sodium channels SCN2A have been identified in patients with seizures, implying their genetic base. We aimed to evaluate the association between SCN2A c. G/A genetic polymorphism among Egyptian children with febrile seizure plus. METHODS The present cross-sectional study was carried out on 100 epileptic infants and children, attendants of the Neurology Unit, pediatric department, Menoufia University Hospitals (Group Ι). The patients were sub-classified into two groups, according to response to anti-epileptic treatment; Group Ι a (drug responder) and Group Ι b (drug-resistant). Evenly divided number of apparently healthy, age and gender-matched children were selected as controls (Group II). A complete history, throughout the systemic examination and radiological & metabolic assessment, whenever needed was provided, all participants were genotyped for SCN2A rs17183814 polymorphism by Restriction Fragment Length Polymorphism (PCR-RFLP). RESULTS Both of A allele and AA, GA genotypes of SCN2A c. 56 G/A were detected more in patients with febrile seizure plus comparison to the control group with a statistically significant difference at frequencies of 17% and 11% and 12% respectively; OR (CI95%): 10.04 (3.49-28.87) and p <0.001. On classifying epileptic patients into 2 subgroups, carriers of SCN2A rs17183814 AA genotype tended to respond poorly to Anti-epileptic Drugs (AEDs). Moreover, multivariate analysis revealed that rs17183814 A allele and positive family history of epilepsy were considered the highest predicted risk factors for the development of epilepsy; p<0.05. CONCLUSION SCN2A rs17183814 (A) allele was specifically associated with developing febrile seizure plus and could modulate the patient's response to anti-epileptic medications.
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Affiliation(s)
- Naglaa Fathy Berseem
- Genetic and Endocrinology Unit, Department of Pediatric, Menoufia University-Shebeen Elkom, Egypt
| | | | - Dalia S Saad
- Faculty of Medicine, Menoufia University, Shebeen Elkom, Egypt
| | - Sameh A Abd Elnaby
- Pediatric Department, Faculty of Medicine, Menoufia University, Shebeen Elkom, Egypt
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14
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Mahling R, Hovey L, Isbell HM, Marx DC, Miller MS, Kilpatrick AM, Weaver LD, Yoder JB, Kim EH, Andresen CNJ, Li S, Shea MA. Na V1.2 EFL domain allosterically enhances Ca 2+ binding to sites I and II of WT and pathogenic calmodulin mutants bound to the channel CTD. Structure 2021; 29:1339-1356.e7. [PMID: 33770503 PMCID: PMC8458505 DOI: 10.1016/j.str.2021.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 12/23/2020] [Accepted: 03/03/2021] [Indexed: 11/23/2022]
Abstract
Neuronal voltage-gated sodium channel NaV1.2 C-terminal domain (CTD) binds calmodulin (CaM) constitutively at its IQ motif. A solution structure (6BUT) and other NMR evidence showed that the CaM N domain (CaMN) is structurally independent of the C-domain (CaMC) whether CaM is bound to the NaV1.2IQp (1,901-1,927) or NaV1.2CTD (1,777-1,937) with or without calcium. However, in the CaM + NaV1.2CTD complex, the Ca2+ affinity of CaMN was more favorable than in free CaM, while Ca2+ affinity for CaMC was weaker than in the CaM + NaV1.2IQp complex. The CTD EF-like (EFL) domain allosterically widened the energetic gap between CaM domains. Cardiomyopathy-associated CaM mutants (N53I(N54I), D95V(D96V), A102V(A103V), E104A(E105A), D129G(D130G), and F141L(F142L)) all bound the NaV1.2 IQ motif favorably under resting (apo) conditions and bound calcium normally at CaMN sites. However, only N53I and A102V bound calcium at CaMC sites at [Ca2+] < 100 μM. Thus, they are expected to respond like wild-type CaM to Ca2+ spikes in excitable cells.
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Affiliation(s)
- Ryan Mahling
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Liam Hovey
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Holly M Isbell
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Dagan C Marx
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Mark S Miller
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Adina M Kilpatrick
- Department of Physics and Astronomy, Drake University, Des Moines, IA 50311-4516, USA
| | - Lisa D Weaver
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Jesse B Yoder
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Elaine H Kim
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Corinne N J Andresen
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Shuxiang Li
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Madeline A Shea
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA.
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15
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Goldberg EM. All our knowledge begins with the antisenses. J Clin Invest 2021; 131:e155233. [PMID: 34850739 PMCID: PMC8631590 DOI: 10.1172/jci155233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Epilepsy is the neurological disorder defined by spontaneous recurrent seizures, which are abnormal patterns of electrical discharge in the brain. A major advance in neurology over the last 20 years is the identification of genetic variation as an important cause of epilepsy, and in particular as a cause of the epileptic encephalopathies, defined by childhood-onset, treatment-resistant epilepsy accompanied by developmental delay leading to intellectual disability. Unfortunately, this progress in genetic diagnosis has yet to translate to effective precision or targeted therapeutics. However, in this issue of the JCI, Li and Jancovski et al. use antisense oligonucleotides (ASO) to treat or prevent epilepsy and epilepsy-associated cognitive and behavioral comorbidities in a mouse model of SCN2A encephalopathy, paralogous to the recurrent human variant SCN2A c.5645G>A (p.R1882Q) associated with epileptic encephalopathy. These findings may inform the development of targeted or personalized therapies for what is currently an incurable and largely untreatable disorder.
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Affiliation(s)
- Ethan M. Goldberg
- Division of Neurology, Department of Pediatrics and
- The Epilepsy NeuroGenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Neuroscience and
- Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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16
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Ganguly S, Thompson CH, George AL. Enhanced slow inactivation contributes to dysfunction of a recurrent SCN2A mutation associated with developmental and epileptic encephalopathy. J Physiol 2021; 599:4375-4388. [PMID: 34287911 PMCID: PMC8446326 DOI: 10.1113/jp281834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/16/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The recurrent SCN2A mutation R853Q is associated with developmental and epileptic encephalopathy with typical onset after the first months of life. Heterologously expressed R853Q channels exhibit an overall loss-of-function as a result of multiple defects in time- and voltage-dependent channel properties. A previously unrecognized enhancement of slow inactivation is conferred by the R853Q mutation and is a major driver of loss-of-function. Enhanced slow inactivation is potentiated in the canonical splice isoform of the channel and this may explain the later onset of symptoms associated with R853Q. ABSTRACT Mutations in voltage gated sodium (NaV ) channel genes, including SCN2A (encoding NaV 1.2), are associated with diverse neurodevelopmental disorders with or without epilepsy that present clinically with varying severity, age-of-onset and pharmacoresponsiveness. We examined the functional properties of the most recurrent SCN2A mutation (R853Q) to determine whether developmentally-regulated alternative splicing impacts dysfunction severity and to investigate effects of the mutation on slow inactivation. We engineered the R853Q mutation into neonatal and adult NaV 1.2 splice isoforms. Channel constructs were heterologously co-expressed in HEK293T cells with human β1 and β2 subunits. Whole-cell patch clamp recording was used to compare time- and voltage-dependent properties of mutant and wild-type channels. The R853Q mutation exhibits an overall loss-of-function attributed to multiple functional defects including a previously undiscovered enhancement of slow inactivation. The mutation exhibited altered voltage dependence of activation and inactivation, slower recovery from inactivation and decreased channel availability during high-frequency depolarizations. More notable were effects on slow inactivation, including a 10-fold slower rate of recovery from slow inactivation exhibited by mutant channels. The impairments in fast inactivation properties were more severe in the neonatal splice isoform, whereas slow inactivation was more pronounced in the splice isoform of the channel expressed predominantly in later childhood. Enhanced later-onset slow inactivation may be a primary driver of the later onset of neurological features associated with this mutation.
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Affiliation(s)
- Surobhi Ganguly
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Christopher H. Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Alfred L. George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL USA
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17
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Chau KK, Zhang P, Urresti J, Amar M, Pramod AB, Chen J, Thomas A, Corominas R, Lin GN, Iakoucheva LM. Full-length isoform transcriptome of the developing human brain provides further insights into autism. Cell Rep 2021; 36:109631. [PMID: 34469739 PMCID: PMC8437376 DOI: 10.1016/j.celrep.2021.109631] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 04/23/2021] [Accepted: 08/09/2021] [Indexed: 12/13/2022] Open
Abstract
Alternative splicing plays an important role in brain development, but its global contribution to human neurodevelopmental diseases (NDDs) requires further investigation. Here we examine the relationships between splicing isoform expression in the brain and de novo loss-of-function mutations from individuals with NDDs. We analyze the full-length isoform transcriptome of the developing human brain and observe differentially expressed isoforms and isoform co-expression modules undetectable by gene-level analyses. These isoforms are enriched in loss-of-function mutations and microexons, are co-expressed with a unique set of partners, and have higher prenatal expression. We experimentally test the effect of splice-site mutations and demonstrate exon skipping in five NDD risk genes, including SCN2A, DYRK1A, and BTRC. Our results suggest that the splice site mutation in BTRC reduces translational efficiency, likely affecting Wnt signaling through impaired degradation of β-catenin. We propose that functional effects of mutations should be investigated at the isoform- rather than gene-level resolution.
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Affiliation(s)
- Kevin K Chau
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA; Department of Biology, University of California, San Diego, La Jolla, CA, USA
| | - Pan Zhang
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Jorge Urresti
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Megha Amar
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Akula Bala Pramod
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Jiaye Chen
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Amy Thomas
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Roser Corominas
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Guan Ning Lin
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Lilia M Iakoucheva
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.
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18
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Wang HG, Bavley CC, Li A, Jones RM, Hackett J, Bayleyen Y, Lee FS, Rajadhyaksha AM, Pitt GS. Scn2a severe hypomorphic mutation decreases excitatory synaptic input and causes autism-associated behaviors. JCI Insight 2021; 6:150698. [PMID: 34156984 PMCID: PMC8410058 DOI: 10.1172/jci.insight.150698] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/17/2021] [Indexed: 12/02/2022] Open
Abstract
SCN2A, encoding the neuronal voltage-gated Na+ channel NaV1.2, is one of the most commonly affected loci linked to autism spectrum disorders (ASDs). Most ASD-associated mutations in SCN2A are loss-of-function mutations, but studies examining how such mutations affect neuronal function and whether Scn2a mutant mice display ASD endophenotypes have been inconsistent. We generated a protein truncation variant Scn2a mouse model (Scn2aΔ1898/+) by CRISPR that eliminates the NaV1.2 channel's distal intracellular C-terminal domain, and we analyzed the molecular and cellular consequences of this variant in a heterologous expression system, in neuronal culture, in brain slices, and in vivo. We also analyzed multiple behaviors in WT and Scn2aΔ1898/+ mice and correlated behaviors with clinical data obtained in human subjects with SCN2A variants. Expression of the NaV1.2 mutant in a heterologous expression system revealed decreased NaV1.2 channel function, and cultured pyramidal neurons isolated from Scn2aΔ1898/+ forebrain showed correspondingly reduced voltage-gated Na+ channel currents without compensation from other CNS voltage-gated Na+ channels. Na+ currents in inhibitory neurons were unaffected. Consistent with loss of voltage-gated Na+ channel currents, Scn2aΔ1898/+ pyramidal neurons displayed reduced excitability in forebrain neuronal culture and reduced excitatory synaptic input onto the pyramidal neurons in brain slices. Scn2aΔ1898/+ mice displayed several behavioral abnormalities, including abnormal social interactions that reflect behavior observed in humans with ASD and with harboring loss-of-function SCN2A variants. This model and its cellular electrophysiological characterizations provide a framework for tracing how a SCN2A loss-of-function variant leads to cellular defects that result in ASD-associated behaviors.
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Affiliation(s)
| | - Charlotte C. Bavley
- Feil Family Brain and Mind Research Institute, and
- Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York, New York, USA
| | - Anfei Li
- Feil Family Brain and Mind Research Institute, and
| | - Rebecca M. Jones
- Weill Cornell Medicine, Center for Autism and the Developing Brain, White Plains, New York, USA
- Weill Cornell Autism Research Program and
- Sackler Institute for Developmental Psychobiology, Department of Psychiatry, Weill Cornell Medicine, New York, New York, USA
| | - Jonathan Hackett
- Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York, New York, USA
| | | | - Francis S. Lee
- Feil Family Brain and Mind Research Institute, and
- Weill Cornell Autism Research Program and
- Sackler Institute for Developmental Psychobiology, Department of Psychiatry, Weill Cornell Medicine, New York, New York, USA
| | - Anjali M. Rajadhyaksha
- Feil Family Brain and Mind Research Institute, and
- Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York, New York, USA
- Weill Cornell Autism Research Program and
| | - Geoffrey S. Pitt
- Cardiovascular Research Institute
- Weill Cornell Autism Research Program and
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19
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Wen Z, Chen J, Zhu B, Lu Y, Chen L. Effects of SCN1A and SCN2A polymorphisms on responsiveness to valproic acid monotherapy in epileptic children: A protocol for systematic review and meta-analysis. Medicine (Baltimore) 2021; 100:e25831. [PMID: 34011048 PMCID: PMC8136989 DOI: 10.1097/md.0000000000025831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND : The gene mutation of coding sodium channel is one of the most important mechanisms in the pathogenesis of epilepsy. There exists a large inter-individual variation in the efficacy of valproic acid (VPA) against epilepsy. What are the genetic polymorphism influences of sodium channels on VPA response is still under discussion. In this study, a meta-analysis was used to further explore the effects of SCN1A and SCN2A gene polymorphism on VPA response in children with epilepsy. METHODS : The PubMed, EMBASE, Web of Science, Chinese National Knowledge Infrastructure, Chinese Science and Technique Journals Database, China Biology Medicine disc, and Wan Fang Database were searched up to April 2021 for appropriate studies regarding the association between SCN1A and SCN2A gene polymorphism on VPA response in children suffering from epilepsy. The meta-analysis was conducted by Review Manager 5.3 software. RESULTS : The results of this meta-analysis will be submitted to a peer-reviewed journal for publication. CONCLUSION : This meta-analysis will summarize the effects of SCN1A and SCN2A gene polymorphisms on VPA response in children with epilepsy. OSF REGISTRATION NUMBER DOI 10.17605/OSF.IO/N2786.
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Affiliation(s)
| | - Jiang Chen
- Department of Pediatrics, Haikou Hospital of the Maternal and Child Health, Haikou, Hainan Province, China
| | - Bin Zhu
- Department of Child Rehabilitation
| | - Yan Lu
- Department of Child Rehabilitation
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20
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Tian X, Zhang Y, Zhang J, Lu Y, Men X, Wang X. Ketogenic Diet in Infants with Early-Onset Epileptic Encephalopathy and SCN2A Mutation. Yonsei Med J 2021; 62:370-373. [PMID: 33779092 PMCID: PMC8007422 DOI: 10.3349/ymj.2021.62.4.370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 12/18/2020] [Accepted: 12/28/2020] [Indexed: 11/29/2022] Open
Abstract
Research has shown mutations in the voltage-gated sodium channel gene SCN2A to be associated with developmental delays and infantile seizures in patients with early-onset epileptic encephalopathies (EOEEs). Here, we report the case of an infant with a de novo SCN2A mutation with EOEE who had medically refractory seizures that improved with a ketogenic diet (KD) implemented at an age less than 2 months. On the day of his birth, the infant presented with a pattern of convulsions with dozens of episodes per day. An initial video electroencephalogram revealed poor reactivity of background activity, with multiple partial episodes starting from the right temporal region, and abnormal electrical activity in the right hemisphere. The seizures previously were not controlled with successive therapy with phenobarbital, topiramate, and levetiracetam. Genetic testing revealed the presence of a mutation in the SCN2A gene (c.4425C>G, p.Asn1475Lys). The infant's seizures decreased significantly with a combination of KD and medication. The present case exemplifies the potential for personalized genomics in identifying the etiology of an illness. Furthermore, the KD appears to feasible in infants younger than 2 months and might elicit good responses to EOEE associated with SCN2A mutation.
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Affiliation(s)
- Xiaoyu Tian
- Department of Pediatrics, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yange Zhang
- Department of Pediatrics, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Jinhong Zhang
- Department of Pediatrics, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yan Lu
- Department of Pediatrics, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xinyi Men
- Department of Pediatrics, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xiuxia Wang
- Department of Pediatrics, The Second Hospital of Hebei Medical University, Shijiazhuang, China.
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21
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Eaton M, Zhang J, Ma Z, Park AC, Lietzke E, Romero CM, Liu Y, Coleman ER, Chen X, Xiao T, Que Z, Lai S, Wu J, Lee JH, Palant S, Nguyen HP, Huang Z, Skarnes WC, Koss WA, Yang Y. Generation and basic characterization of a gene-trap knockout mouse model of Scn2a with a substantial reduction of voltage-gated sodium channel Na v 1.2 expression. Genes Brain Behav 2021; 20:e12725. [PMID: 33369088 DOI: 10.1111/gbb.12725] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022]
Abstract
Large-scale genetic studies revealed SCN2A as one of the most frequently mutated genes in patients with neurodevelopmental disorders. SCN2A encodes for the voltage-gated sodium channel isoform 1.2 (Nav 1.2) expressed in the neurons of the central nervous system. Homozygous knockout (null) of Scn2a in mice is perinatal lethal, whereas heterozygous knockout of Scn2a (Scn2a+/- ) results in mild behavior abnormalities. The Nav 1.2 expression level in Scn2a+/- mice is reported to be around 50-60% of the wild-type (WT) level, which indicates that a close to 50% reduction of Nav 1.2 expression may not be sufficient to lead to major behavioral phenotypes in mice. To overcome this barrier, we characterized a novel mouse model of severe Scn2a deficiency using a targeted gene-trap knockout (gtKO) strategy. This approach produces viable homozygous mice (Scn2agtKO/gtKO ) that can survive to adulthood, with about a quarter of Nav 1.2 expression compared to WT mice. Innate behaviors like nesting and mating were profoundly disrupted in Scn2agtKO/gtKO mice. Notably, Scn2agtKO/gtKO mice have a significantly decreased center duration compared to WT in the open field test, suggesting anxiety-like behaviors in a novel, open space. These mice also have decreased thermal and cold tolerance. Additionally, Scn2agtKO/gtKO mice have increased fix-pattern exploration in the novel object exploration test and a slight increase in grooming, indicating a detectable level of repetitive behaviors. They bury little to no marbles and have decreased interaction with novel objects. These Scn2a gene-trap knockout mice thus provide a unique model to study pathophysiology associated with severe Scn2a deficiency.
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Affiliation(s)
- Muriel Eaton
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Jingliang Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Zhixiong Ma
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Anthony C Park
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Emma Lietzke
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Chloé M Romero
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Yushuang Liu
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Emily R Coleman
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Xiaoling Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Tiange Xiao
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Zhefu Que
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Shirong Lai
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Jiaxiang Wu
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Ji Hea Lee
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Sophia Palant
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Huynhvi P Nguyen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Zhuo Huang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - William C Skarnes
- Department of Cellular Engineering, The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA
| | - Wendy A Koss
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
- Office of the Executive Vice President for Research and Partnerships, Purdue University, West Lafayette, Indiana, USA
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
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22
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Hanly C, Shah H, Au PYB, Murias K. Description of neurodevelopmental phenotypes associated with 10 genetic neurodevelopmental disorders: A scoping review. Clin Genet 2021; 99:335-346. [PMID: 33179249 DOI: 10.1111/cge.13882] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/22/2020] [Accepted: 11/08/2020] [Indexed: 12/25/2022]
Abstract
Neurodevelopmental disorders (NDDs) are a heterogeneous group of conditions including intellectual disability, global developmental delay, autism spectrum disorder, and attention deficit hyperactivity disorder. Advances in genetic diagnostic technology have led to the identification of a number of NDD-associated genes, but reports of cognitive and developmental outcomes in affected individuals have been variable. The objective of this scoping review is to synthesize available information pertaining to the developmental outcomes of individuals with pathogenic variants in ten emerging recurrent NDD-associated genes identified from large scale sequencing studies; ADNP, ANKRD11, ARID1B, CHD2, CHD8, CTNNB1, DDX3X, DYRK1A, SCN2A, and SYNGAP1. After a comprehensive search, 260 articles were selected that reported on neurodevelopmental measures or diagnoses. We identify the spectrum of developmental outcomes for each genetic NDD, including prevalence of intellectual disability, frequency of co-morbid NDDs such as ADHD and autism, and commonly reported medical issues that can help inform diagnosis and treatment. There are significant gaps in our understanding of the natural history of these conditions. Future research focusing on barriers to assessment, the development of modified assessment tools appropriate for long-term outcomes in genetic NDD, and collection of longitudinal data will increase understanding of prognosis in these conditions and inform evaluations of treatment.
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Affiliation(s)
- Ciara Hanly
- Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Harshil Shah
- Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Ping Yee Billie Au
- Cumming School of Medicine, University of Calgary, Calgary, Canada
- Department of Medical Genetics, University of Calgary, Calgary, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Kara Murias
- Cumming School of Medicine, University of Calgary, Calgary, Canada
- Departments of Pediatrics and Clinical Neuroscience, University of Calgary, Calgary, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
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23
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DeKeyser JM, Thompson CH, George AL. Cryptic prokaryotic promoters explain instability of recombinant neuronal sodium channels in bacteria. J Biol Chem 2021; 296:100298. [PMID: 33460646 PMCID: PMC7948969 DOI: 10.1016/j.jbc.2021.100298] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/09/2021] [Accepted: 01/12/2021] [Indexed: 11/18/2022] Open
Abstract
Mutations in genes encoding the human-brain-expressed voltage-gated sodium (NaV) channels NaV1.1, NaV1.2, and NaV1.6 are associated with a variety of human diseases including epilepsy, autism spectrum disorder, familial migraine, and other neurodevelopmental disorders. A major obstacle hindering investigations of the functional consequences of brain NaV channel mutations is an unexplained instability of the corresponding recombinant complementary DNA (cDNA) when propagated in commonly used bacterial strains manifested by high spontaneous rates of mutation. Here, using a combination of in silico analysis, random and site-directed mutagenesis, we investigated the cause for instability of human NaV1.1 cDNA. We identified nucleotide sequences within the NaV1.1 coding region that resemble prokaryotic promoter-like elements, which are presumed to drive transcription of translationally toxic mRNAs in bacteria as the cause of the instability. We further demonstrated that mutations disrupting these elements mitigate the instability. Extending these observations, we generated full-length human NaV1.1, NaV1.2, and NaV1.6 plasmids using one or two introns that interrupt the latent reading frames along with a minimum number of silent nucleotide changes that achieved stable propagation in bacteria. Expression of the stabilized sequences in cultured mammalian cells resulted in functional NaV channels with properties that matched their parental constructs. Our findings explain a widely observed instability of recombinant neuronal human NaV channels, and we describe re-engineered plasmids that attenuate this problem.
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Affiliation(s)
- Jean-Marc DeKeyser
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
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24
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Abstract
The term Episodic Ataxias (EA) was originally used for a few autosomal dominant diseases, characterized by attacks of cerebellar dysfunction of variable duration and frequency, often accompanied by other ictal and interictal signs. The original group subsequently grew to include other very rare EAs, frequently reported in single families, for some of which no responsible gene was found. The clinical spectrum of these diseases has been enormously amplified over time. In addition, episodes of ataxia have been described as phenotypic variants in the context of several different disorders. The whole group is somewhat confused, since a strong evidence linking the mutation to a given phenotype has not always been established. In this review we will collect and examine all instances of ataxia episodes reported so far, emphasizing those for which the pathophysiology and the clinical spectrum is best defined.
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Affiliation(s)
- Paola Giunti
- Laboratory of Neurogenetics, Department of Molecular Neuroscience, UCL Institute of Neurology, London WC2N 5DU, UK
- Correspondence: (P.G.); (M.F.)
| | - Elide Mantuano
- Laboratory of Neurogenetics, Institute of Translational Pharmacology, National Research Council of Italy, 00133 Rome, Italy;
| | - Marina Frontali
- Laboratory of Neurogenetics, Institute of Translational Pharmacology, National Research Council of Italy, 00133 Rome, Italy;
- Correspondence: (P.G.); (M.F.)
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25
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Encinas AC, Watkins JC, Longoria IA, Johnson JP, Hammer MF. Variable patterns of mutation density among NaV1.1, NaV1.2 and NaV1.6 point to channel-specific functional differences associated with childhood epilepsy. PLoS One 2020; 15:e0238121. [PMID: 32845893 PMCID: PMC7449494 DOI: 10.1371/journal.pone.0238121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 08/10/2020] [Indexed: 11/28/2022] Open
Abstract
Variants implicated in childhood epilepsy have been identified in all four voltage-gated sodium channels that initiate action potentials in the central nervous system. Previous research has focused on the functional effects of particular variants within the most studied of these channels (NaV1.1, NaV1.2 and NaV1.6); however, there have been few comparative studies across channels to infer the impact of mutations in patients with epilepsy. Here we compare patterns of variation in patient and public databases to test the hypothesis that regions of known functional significance within voltage-gated sodium (NaV) channels have an increased burden of deleterious variants. We assessed mutational burden in different regions of the Nav channels by (1) performing Fisher exact tests on odds ratios to infer excess variants in domains, segments, and loops of each channel in patient databases versus public “control” databases, and (2) comparing the cumulative distribution of variant sites along DNA sequences of each gene in patient and public databases (i.e., independent of protein structure). Patient variant density was concordant among channels in regions known to play a role in channel function, with statistically significant higher patient variant density in S4-S6 and DIII-DIV and an excess of public variants in SI-S3, DI-DII, DII-DIII. On the other hand, channel-specific patterns of patient burden were found in the NaV1.6 inactivation gate and NaV1.1 S5-S6 linkers, while NaV1.2 and NaV1.6 S4-S5 linkers and S5 segments shared patient variant patterns that contrasted with those in NaV1.1. These different patterns may reflect different roles played by the NaV1.6 inactivation gate in action potential propagation, and by NaV1.1 S5-S6 linkers in loss of function and haploinsufficiency. Interestingly, NaV1.2 and NaV1.6 both lack amino acid substitutions over significantly long stretches in both the patient and public databases suggesting that new mutations in these regions may cause embryonic lethality or a non-epileptic disease phenotype.
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Affiliation(s)
- Alejandra C. Encinas
- Graduate Program in Genetics, University of Arizona, Tucson, Arizona, United States of America
| | - Joseph C. Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | - Iris Arenas Longoria
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | | | - Michael F. Hammer
- Department of Neurology, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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Mason ER, Cummins TR. Differential Inhibition of Human Nav1.2 Resurgent and Persistent Sodium Currents by Cannabidiol and GS967. Int J Mol Sci 2020; 21:ijms21072454. [PMID: 32244818 PMCID: PMC7177867 DOI: 10.3390/ijms21072454] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 12/24/2022] Open
Abstract
Many epilepsy patients are refractory to conventional antiepileptic drugs. Resurgent and persistent currents can be enhanced by epilepsy mutations in the Nav1.2 channel, but conventional antiepileptic drugs inhibit normal transient currents through these channels, along with aberrant resurgent and persistent currents that are enhanced by Nav1.2 epilepsy mutations. Pharmacotherapies that specifically target aberrant resurgent and/or persistent currents would likely have fewer unwanted side effects and be effective in many patients with refractory epilepsy. This study investigated the effects of cannbidiol (CBD) and GS967 (each at 1 μM) on transient, resurgent, and persistent currents in human embryonic kidney (HEK) cells stably expressing wild-type hNav1.2 channels. We found that CBD preferentially inhibits resurgent currents over transient currents in this paradigm; and that GS967 preferentially inhibits persistent currents over transient currents. Therefore, CBD and GS967 may represent a new class of more targeted and effective antiepileptic drugs.
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Affiliation(s)
- Emily R. Mason
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, IUPUI campus, Indianapolis, IN 46202, USA
- Correspondence:
| | - Theodore R. Cummins
- Department of Biology, Purdue School of Science, IUPUI campus, Indianapolis, IN 46202, USA;
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Risner ML, McGrady NR, Pasini S, Lambert WS, Calkins DJ. Elevated ocular pressure reduces voltage-gated sodium channel NaV1.2 protein expression in retinal ganglion cell axons. Exp Eye Res 2020; 190:107873. [PMID: 31734278 PMCID: PMC6957720 DOI: 10.1016/j.exer.2019.107873] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/16/2019] [Accepted: 11/13/2019] [Indexed: 01/05/2023]
Abstract
Glaucoma is an age-related neurodegenerative disease that is commonly associated with sensitivity to intraocular pressure. The disease selectively targets retinal ganglion cells (RGCs) and constituent axons. RGC axons are rich in voltage-gated sodium channels, which are essential for action potential initiation and regeneration. Here, we identified voltage-dependent sodium channel, NaV1.2, in the retina, examined how this channel contributes to RGC light responses, and monitored NaV1.2 mRNA and protein expression in the retina during progression of modeled glaucoma. We found NaV1.2 is predominately localized in ganglion cell intraretinal axons with dispersed expression in the outer and inner plexiform layers. We showed Phrixotoxin-3, a potent NaV1.2 channel blocker, significantly decreased RGC electrical activity in a dose-dependent manner with an IC50 of 40 nM. Finally, we found four weeks of raised intraocular pressure (30% above baseline) significantly increased NaV1.2 mRNA expression but reduced NaV1.2 protein level in the retina up to 57% (p < 0.001). Following prolonged intraocular pressure elevation, NaV1.2 protein expression particularly diminished at distal sections of ganglion cell intraretinal axons (p ≤ 0.01). Our results suggest NaV1.2 might be a therapeutic target during disease progression to maintain RGC excitability, preserving presynaptic connections through action potential backpropagation.
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Affiliation(s)
- Michael L Risner
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, 11435 Medical Research Building IV, 2215B Garland Ave, Nashville, TN, 37232-0654, USA
| | - Nolan R McGrady
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, 11435 Medical Research Building IV, 2215B Garland Ave, Nashville, TN, 37232-0654, USA
| | - Silvia Pasini
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, 11435 Medical Research Building IV, 2215B Garland Ave, Nashville, TN, 37232-0654, USA
| | - Wendi S Lambert
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, 11435 Medical Research Building IV, 2215B Garland Ave, Nashville, TN, 37232-0654, USA
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, 11435 Medical Research Building IV, 2215B Garland Ave, Nashville, TN, 37232-0654, USA.
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Mason ER, Wu F, Patel RR, Xiao Y, Cannon SC, Cummins TR. Resurgent and Gating Pore Currents Induced by De Novo SCN2A Epilepsy Mutations. eNeuro 2019; 6:ENEURO.0141-19.2019. [PMID: 31558572 PMCID: PMC6795554 DOI: 10.1523/eneuro.0141-19.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 09/12/2019] [Accepted: 09/16/2019] [Indexed: 12/31/2022] Open
Abstract
Over 150 mutations in the SCN2A gene, which encodes the neuronal Nav1.2 protein, have been implicated in human epilepsy cases. Of these, R1882Q and R853Q are two of the most commonly reported mutations. This study utilized voltage-clamp electrophysiology to characterize the biophysical effects of the R1882Q and R853Q mutations on the hNav1.2 channel, including their effects on resurgent current and gating pore current, which are not typically investigated in the study of Nav1.2 channel mutations. HEK cells transiently transfected with DNA encoding either wild-type (WT) or mutant hNav1.2 revealed that the R1882Q mutation induced a gain-of-function phenotype, including slowed fast inactivation, depolarization of the voltage dependence of inactivation, and increased persistent current. In this model system, the R853Q mutation primarily produced loss-of-function effects, including reduced transient current amplitude and density, hyperpolarization of the voltage dependence of inactivation, and decreased persistent current. The presence of a Navβ4 peptide (KKLITFILKKTREK-OH) in the pipette solution induced resurgent currents, which were increased by the R1882Q mutation and decreased by the R853Q mutation. Further study of the R853Q mutation in Xenopus oocytes indicated a reduced surface expression and revealed a robust gating pore current at negative membrane potentials, a function absent in the WT channel. This not only shows that different epileptogenic point mutations in hNav1.2 have distinct biophysical effects on the channel, but also illustrates that individual mutations can have complex consequences that are difficult to identify using conventional analyses. Distinct mutations may, therefore, require tailored pharmacotherapies in order to eliminate seizures.
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Affiliation(s)
- Emily R Mason
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Fenfen Wu
- Department of Physiology, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA 90095-1751
| | - Reesha R Patel
- Program in Medical Neuroscience, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Yucheng Xiao
- School of Science, Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA 90095-1751
| | - Theodore R Cummins
- School of Science, Biology Department Chair, Indiana University-Purdue University of Indianapolis, Indianapolis, IN 46202
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Sahli M, Zrhidri A, Elaloui SC, Smaili W, Lyahyai J, Oudghiri FZ, Sefiani A. Clinical exome sequencing identifies two novel mutations of the SCN1A and SCN2A genes in Moroccan patients with epilepsy: a case series. J Med Case Rep 2019; 13:266. [PMID: 31439038 PMCID: PMC6706917 DOI: 10.1186/s13256-019-2203-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/17/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Epilepsy is the most common neurological disorder that causes spontaneous, unprovoked, and recurrent seizures. Epilepsy is clinically and genetically heterogeneous with various modes of inheritance. The complexity of epilepsy presents a challenge and identification of the causal genetic mutation allows diagnosis, genetic counseling, predicting prognosis, and, in some cases, treatment decisions. Clinical exome sequencing is actually becoming a powerful approach for molecular diagnosis of heterogeneous neurological disorders in clinical practice. CASE PRESENTATION We report our observations of three unrelated Moroccan patients referred to our genetics department for molecular diagnosis of epilepsy: a 4-year-old Moroccan boy, a 3-year-old Moroccan girl, and a 7-year-old Moroccan boy. Due to the heterogeneity and complexity of epilepsy, we performed clinical exome sequencing followed by targeted analysis of 936 epilepsy genes. A total of three mutations were identified in known epilepsy genes (SCN1A, SCN2A). By clinical exome sequencing, we identified two novel mutations: c.4973C>A (p.Thr1658Lys) in SCN1A gene and c.1283A>G (p.Tyr428Cys) in the SCN2A gene, whereas the third mutation c.3295G>T (p.Glu1099*) was already described in patients with Dravet syndrome. CONCLUSION This study demonstrates that clinical exome sequencing is an effective diagnosis tool to investigate this group of diseases with huge diversity and defends its use in clinical routine.
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Affiliation(s)
- Maryem Sahli
- Centre de Recherche en Génomique des Pathologies Humaines (GENOPATH), Faculté de Médecine et de Pharmacie, Mohammed V University of Rabat, 10100 Rabat, Morocco
- Département de génétique médicale, Institut National d’Hygiène, BP 769 Agdal, 10090 Rabat, Morocco
- Département de Génétique Médicale, Institut National d’Hygiène, 7Avenue Ibn Batouta, B.P. 769, 11400 Rabat, Morocco
| | - Abdelali Zrhidri
- Centre de Recherche en Génomique des Pathologies Humaines (GENOPATH), Faculté de Médecine et de Pharmacie, Mohammed V University of Rabat, 10100 Rabat, Morocco
- Département de génétique médicale, Institut National d’Hygiène, BP 769 Agdal, 10090 Rabat, Morocco
| | - Siham Chafai Elaloui
- Centre de Recherche en Génomique des Pathologies Humaines (GENOPATH), Faculté de Médecine et de Pharmacie, Mohammed V University of Rabat, 10100 Rabat, Morocco
| | - Wiam Smaili
- Département de génétique médicale, Institut National d’Hygiène, BP 769 Agdal, 10090 Rabat, Morocco
| | - Jaber Lyahyai
- Centre de Recherche en Génomique des Pathologies Humaines (GENOPATH), Faculté de Médecine et de Pharmacie, Mohammed V University of Rabat, 10100 Rabat, Morocco
| | | | - Abdelaziz Sefiani
- Centre de Recherche en Génomique des Pathologies Humaines (GENOPATH), Faculté de Médecine et de Pharmacie, Mohammed V University of Rabat, 10100 Rabat, Morocco
- Département de génétique médicale, Institut National d’Hygiène, BP 769 Agdal, 10090 Rabat, Morocco
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Vlachou V, Larsen L, Pavlidou E, Ismayilova N, Mazarakis ND, Scala M, Pantazi M, Mankad K, Kinali M. SCN2A mutation in an infant with Ohtahara syndrome and neuroimaging findings: expanding the phenotype of neuronal migration disorders. J Genet 2019; 98:54. [PMID: 31204721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Neuronal migration disorders (NMDs) are a heterogeneous group of conditions caused by the abnormal migration of neuroblasts in the developing brain and nervous system, resulting in severe developmental impairment, intractable epilepsy and intellectual disability (Spalice et al. 2009). To date, many genes have been identified as the leading cause of migration defects, i.e. agyria/pachygyria, polymicrogyria, heterotopias, agenesis of the corpus callosum and agenesis of the cranial nerves (Spalice et al. 2009). Here, we present a patient with early infantile epileptic encephalopathy (Ohtahara syndrome) with seizure onset on the first dayof life, severe developmental delay and an abnormal brain MRI with excessive folding of small, fused gyri and bilateral perisylvian polymicrogyria, suggestive of neuronal migration disorder. To clarify the unknown aetiology, we conducted whole-exome sequencing, which detected a de novo missense variant (c.5308A>T; p.(Met1770Leu)) in the SCN2A gene. This is a report of SCN2A gene variant identified in a patient with neuronal migration disorder which could further expand the phenotypic spectrum of these genetic disorders.
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Affiliation(s)
- Victoria Vlachou
- Department of Paediatric Neurology, Chelsea and Westminster NHS Foundation Trust, London SW10 9NH, UK.
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Kamate M, Detroja M. Uncommon Treatable Genetic Epileptic Encephalopathies. Indian Pediatr 2019; 56:427-428. [PMID: 31102386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Mahesh Kamate
- Department of Pediatric Neurology, KLE University's JN Medical College, Belgaum, India.
| | - Mayank Detroja
- Department of Pediatric Neurology, KLE University's JN Medical College, Belgaum, India
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Abstract
SCN2A mutations have been described in a very broad spectrum of clinical phenotypes including benign (familial) neonatal/infantile seizures and early infantile epileptic encephalopathies (EIEE) as Ohtahara syndrome (OS), Dravet syndrome (DS), epilepsy of infancy with migrating focal seizures and West syndrome (WS). Treatment modalities for epilepsy caused by SCN2A mutations mainly consist of sodium channel blockers but ketogenic diet (KD) is also considered as an option of treatment for intractible seizures caused by SCN2A mutations. Because of the wide nature of the heterogeneity of mutations related to SCN2A gene, the clinical phenotypes vary in severity and treatment response to KD has been reported to be controversial. We present a patient diagnosed with OS associated with a novel SCN2A mutation (c.408G > A, p.Met136lle; OMIM®: 182390) who had a complete resolution of seizures and EEG abnormalities with KD commenced at 39 days of age. As far as we are aware our case is the youngest patient with SCN2A mutation treated with KD with complete resolution of epilepsy at an early age and has been seizure free of antiepileptic medications for a long duration.
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Affiliation(s)
- Dilsad Turkdogan
- Division of Child Neurology, Department of Pediatrics, Marmara University, Faculty of Medicine, Turkey
| | - Gulten Thomas
- Division of Child Neurology, Department of Pediatrics, Marmara University, Faculty of Medicine, Turkey.
| | - Birsen Demirel
- Department of Nutrition and Dietetics, Bilgi University School of Medicine, Turkey
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Yang X, Yan Y, Fang S, Zeng S, Ma H, Qian L, Chen X, Wei J, Gong Z, Xu Z. Comparison of oxcarbazepine efficacy and MHD concentrations relative to age and BMI: Associations among ABCB1, ABCC2, UGT2B7, and SCN2A polymorphisms. Medicine (Baltimore) 2019; 98:e14908. [PMID: 30896644 PMCID: PMC6708905 DOI: 10.1097/md.0000000000014908] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Genetic polymorphisms are related to the concentration and efficacy of oxcarbazepine (OXC). 10-Hydroxycarbazepine (MHD) is the major pharmacologically active metabolite of OXC, and it exerts an antiepileptic effect. This study aimed to explore the connection between the MHD concentration and genes such as ATP-binding cassette B1 (ABCB1), ATP-binding cassette C2 (ABCC2), UDP-glucuronosyltransferase-2B7 and sodium voltage-gated channel alpha subunit 2 (SCN2A), which participate in the antiepileptic function of OXC.Total 218 Chinese epileptic patients, were stratified into different groups according to their age, body mass index (BMI) and OXC efficacy. The genotypes of 7 single nucleotide polymorphisms in all subjects were determined by polymerase chain reaction-improved multiple ligase detection reaction assay. The MHD plasma concentration was detected by high-performance liquid chromatography and then standardized through dosage and body weight.In general, the ABCC2 rs2273697 mutant (P = .026) required a significantly higher standardized MHD concentration. For age groups, carriers of the ABCC2 rs2273697 mutant showed a significantly higher standardized MHD concentration than noncarriers in the juvenile group (P = .033). In terms of BMI, a significantly higher standardized MHD concentration was found in the ABCB1 rs2032582 mutant of the normal weight group (P = .026). The SCN2A rs17183814 mutant required a significantly higher OXC maintenance (P = .014) in the low-weight group, while lower OXC maintenance dose (P = .044) and higher standardized MHD concentration (P = .007) in the overweight group.The ABCC2 rs2273697 polymorphism was significantly associated with MHD plasma concentration in the whole patient cohort and in patients stratified by different ages, this finding provides potential theoretical guidance for the rational and safe clinical use of OXC.
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Affiliation(s)
- Xue Yang
- Department of Pharmacy
- Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders
| | - Yuanliang Yan
- Department of Pharmacy
- Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders
| | - Shu Fang
- Department of Pharmacy
- Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders
| | - Shuangshuang Zeng
- Department of Pharmacy
- Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders
| | | | - Long Qian
- Department of Pharmacy
- Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders
| | - Xi Chen
- Department of Pharmacy
- Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders
| | - Jie Wei
- Department of Pharmacy
- Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders
| | - Zhicheng Gong
- Department of Pharmacy
- Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders
| | - Zhijie Xu
- Department of Pathology, Xiangya Hospital, Central South University, China
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Abstract
RATIONALE The phenotypic spectrum caused by SCN2A mutations includes benign neonatal/infantile seizures, Ohtahara syndrome, infantile spasms, West syndrome, and other unclassified epileptic phenotypes. Mutations in SCN2A have been implicated in neonatal seizure cases. Here, we described a Chinese family with 2 members having juvenile-onset myoclonus and identified a novel SCN2A point mutation within this family. PATIENT CONCERNS The 21-year-old male proband suffered from frequent myoclonus at 11 years old with subsequent progressive ataxia. His elder maternal half-sister also experienced myoclonus. Genomic DNA of the patients was extracted from the peripheral blood cells of the proband, elder maternal half-sister, parents, and uncle of the proband. Targeted next-generation sequencing was used to screen gene mutations in the proband. The potential functional effects of mutations within SCN2A were predicted In silico analyses. DIAGNOSES Genetic testing revealed a novel SCN2A variant, c.T4820C, which contains a highly conserved amino acid substitution within segment S5 (p.V1607A). This mutation was predicted to produce a dysfunctional Nav1.2 protein by Mutation Taster and Protein Variation Effect Analyzer (PROVEAN). Genotype-phenotype correlation showed an incomplete penetrance of p.V1607A. INTERVENTIONS The proband was treated by multiple antiepileptic drugs. These included carbamazepine, oxcarbazepine, valproate, and topiramate. OUTCOMES The duration of follow up was 2 years, and the proband developed drug-resistant epilepsy. LESSONS The case gives us the lesson that SCN2A mutation can contribute to juvenile-onset myoclonus. Our findings extend the spectrums of SCN2A mutations and the clinical features of patients with SCN2A mutations.
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Zhao L, Chang H, Zhou DS, Cai J, Fan W, Tang W, Tang W, Li X, Liu W, Liu F, He Y, Bai Y, Sun Y, Dai J, Li L, Xiao X, Zhang C, Li M. Replicated associations of FADS1, MAD1L1, and a rare variant at 10q26.13 with bipolar disorder in Chinese population. Transl Psychiatry 2018; 8:270. [PMID: 30531795 PMCID: PMC6286364 DOI: 10.1038/s41398-018-0337-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 10/07/2018] [Accepted: 11/13/2018] [Indexed: 12/12/2022] Open
Abstract
Genetic analyses of psychiatric illnesses, such as bipolar disorder (BPD), have revealed essential information regarding the underlying pathological mechanisms. While such studies in populations of European ancestry have achieved prominent success, understanding the genetic risk factors of these illnesses (especially BPD) in Chinese population remains an urgent task. Given the lack of genome-wide association study (GWAS) of BPD in Chinese population from Mainland China, replicating the previously reported GWAS hits in distinct populations will provide valuable information for future GWAS analysis in Han Chinese. In the present study, we have recruited 1146 BPD cases and 1956 controls from Mainland China for genetic analyses, as well as 65 Han Chinese brain amygdala tissues for mRNA expression analyses. Using this clinical sample, one of the largest Han Chinese BPD samples till now, we have conducted replication analyses of 21 single nucleotide polymorphisms (SNPs) extracted from previous GWAS of distinct populations. Among the 21 tested SNPs, 16 showed the same direction of allelic effects in our samples compared with previous studies; 6 SNPs achieved nominal significance (p < 0.05) at one-tailed test, and 2 additional SNPs showed marginal significance (p < 0.10). Aside from replicating previously reported BPD risk SNPs, we herein also report several intriguing findings: (1) the SNP rs174576 was associated with BPD in our Chinese sample and in the overall global meta-analysis, and was significantly correlated with FADS1 mRNA in diverse public RNA-seq datasets as well as our in house collected Chinese amygdala samples; (2) two (partially) independent SNPs in MAD1L1 were both significantly associated with BPD in our Chinese sample, which was also supported by haplotype analysis; (3) a rare SNP rs78089757 in 10q26.13 region was a genome-wide significant variant for BPD in East Asians, and this SNP was near monomorphic in Europeans. In sum, these results confirmed several significant BPD risk genes. We hope this Chinese BPD case-control sample and the current brain amygdala tissues (with continuous increasing sample size in the near future) will provide helpful resources in elucidating the genetic and molecular basis of BPD in this major world population.
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Affiliation(s)
- Lijuan Zhao
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Hong Chang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, China
| | - Dong-Sheng Zhou
- Department of Psychiatry, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Jun Cai
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weixing Fan
- Jinhua Second Hospital, Jinhua, Zhejiang, China
| | - Wei Tang
- Wenzhou Kangning Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Wenxin Tang
- Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang, China
| | - Xingxing Li
- Department of Psychiatry, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Weiqing Liu
- Department of Psychiatry, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Fang Liu
- Department of Psychiatry, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Yuanfang He
- Department of Psychiatry, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Yan Bai
- Department of Psychiatry, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Yan Sun
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China
- Chinese Brain Bank Center, Wuhan, Hubei, China
| | - Jiapei Dai
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China
- Chinese Brain Bank Center, Wuhan, Hubei, China
| | - Lingyi Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, China
| | - Xiao Xiao
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, China.
| | - Chen Zhang
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Ming Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, China.
- CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.
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Maksemous N, Smith RA, Sutherland HG, Sampaio H, Griffiths LR. Whole-Exome Sequencing Implicates SCN2A in Episodic Ataxia, but Multiple Ion Channel Variants May Contribute to Phenotypic Complexity. Int J Mol Sci 2018; 19:ijms19103113. [PMID: 30314295 PMCID: PMC6213185 DOI: 10.3390/ijms19103113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/08/2018] [Accepted: 10/10/2018] [Indexed: 01/04/2023] Open
Abstract
Although the clinical use of targeted gene sequencing-based diagnostics is valuable, whole-exome sequencing has also emerged as a successful diagnostic tool in molecular genetics laboratories worldwide. Molecular genetic tests for episodic ataxia type 2 (EA2) usually target only the specific calcium channel gene (CACNA1A) that is known to cause EA2. In cases where no mutations are identified in the CACNA1A gene, it is important to identify the causal gene so that more effective treatment can be prioritized for patients. Here we present a case of a proband with a complex episodic ataxias (EA)/seizure phenotype with an EA-affected father; and an unaffected mother, all negative for CACNA1A gene mutations. The trio was studied by whole-exome sequencing to identify candidate genes responsible for causing the complex EA/seizure phenotype. Three rare or novel variants in Sodium channel α2-subunit; SCN2A (c.3973G>T: p.Val1325Phe), Potassium channel, Kv3.2; KCNC2 (c.1006T>C: p.Ser336Pro) and Sodium channel Nav1.6; SCN8A (c.3421C>A: p.Pro1141Thr) genes were found in the proband. While the SCN2A variant is likely to be causal for episodic ataxia, each variant may potentially contribute to the phenotypes observed in this family. This study highlights that a major challenge of using whole-exome/genome sequencing is the identification of the unique causative mutation that is associated with complex disease.
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Affiliation(s)
- Neven Maksemous
- Genomics Research Centre, Institute of Health and Biomedical Innovation (IHBI), School of Biomedical Sciences, Queensland University of Technology (QUT), Q Block, 60 Musk Ave, Kelvin Grove Campus, Brisbane 4059, QLD, Australia.
| | - Robert A Smith
- Genomics Research Centre, Institute of Health and Biomedical Innovation (IHBI), School of Biomedical Sciences, Queensland University of Technology (QUT), Q Block, 60 Musk Ave, Kelvin Grove Campus, Brisbane 4059, QLD, Australia.
| | - Heidi G Sutherland
- Genomics Research Centre, Institute of Health and Biomedical Innovation (IHBI), School of Biomedical Sciences, Queensland University of Technology (QUT), Q Block, 60 Musk Ave, Kelvin Grove Campus, Brisbane 4059, QLD, Australia.
| | - Hugo Sampaio
- Department of Women and Children's Health, Randwick Campus, University of New South Wales, Randwick 2031, NSW, Australia.
- Sydney Children's Hospital, Randwick 2031, NSW, Australia.
| | - Lyn R Griffiths
- Genomics Research Centre, Institute of Health and Biomedical Innovation (IHBI), School of Biomedical Sciences, Queensland University of Technology (QUT), Q Block, 60 Musk Ave, Kelvin Grove Campus, Brisbane 4059, QLD, Australia.
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Flood E, Boiteux C, Allen TW. Selective ion permeation involves complexation with carboxylates and lysine in a model human sodium channel. PLoS Comput Biol 2018; 14:e1006398. [PMID: 30208027 PMCID: PMC6152994 DOI: 10.1371/journal.pcbi.1006398] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 09/24/2018] [Accepted: 07/24/2018] [Indexed: 12/21/2022] Open
Abstract
Bacterial and human voltage-gated sodium channels (Navs) exhibit similar cation selectivity, despite their distinct EEEE and DEKA selectivity filter signature sequences. Recent high-resolution structures for bacterial Navs have allowed us to learn about ion conduction mechanisms in these simpler homo-tetrameric channels, but our understanding of the function of their mammalian counterparts remains limited. To probe these conduction mechanisms, a model of the human Nav1.2 channel has been constructed by grafting residues of its selectivity filter and external vestibular region onto the bacterial NavRh channel with atomic-resolution structure. Multi-μs fully atomistic simulations capture long time-scale ion and protein movements associated with the permeation of Na+ and K+ ions, and their differences. We observe a Na+ ion knock-on conduction mechanism facilitated by low energy multi-carboxylate/multi-Na+ complexes, akin to the bacterial channels. These complexes involve both the DEKA and vestibular EEDD rings, acting to draw multiple Na+ into the selectivity filter and promote permeation. When the DEKA ring lysine is protonated, we observe that its ammonium group is actively participating in Na+ permeation, presuming the role of another ion. It participates in the formation of a stable complex involving carboxylates that collectively bind both Na+ and the Lys ammonium group in a high-field strength site, permitting pass-by translocation of Na+. In contrast, multiple K+ ion complexes with the DEKA and EEDD rings are disfavored by up to 8.3 kcal/mol, with the K+-lysine-carboxylate complex non-existent. As a result, lysine acts as an electrostatic plug that partially blocks the flow of K+ ions, which must instead wait for isomerization of lysine downward to clear the path for K+ passage. These distinct mechanisms give us insight into the nature of ion conduction and selectivity in human Nav channels, while uncovering high field strength carboxylate binding complexes that define the more general phenomenon of Na+-selective ion transport in nature.
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Affiliation(s)
- Emelie Flood
- School of Science, RMIT University, Melbourne, Vic, Australia
| | - Céline Boiteux
- School of Science, RMIT University, Melbourne, Vic, Australia
| | - Toby W. Allen
- School of Science, RMIT University, Melbourne, Vic, Australia
- * E-mail:
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Nunes D, Kuner T. Axonal sodium channel NaV1.2 drives granule cell dendritic GABA release and rapid odor discrimination. PLoS Biol 2018; 16:e2003816. [PMID: 30125271 PMCID: PMC6117082 DOI: 10.1371/journal.pbio.2003816] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 08/30/2018] [Accepted: 08/06/2018] [Indexed: 12/19/2022] Open
Abstract
Dendrodendritic synaptic interactions between olfactory bulb mitral and granule cells represent a key neuronal mechanism of odor discrimination. Dendritic release of gamma-aminobutyric acid (GABA) from granule cells contributes to stimulus-dependent, rapid, and accurate odor discrimination, yet the physiological mechanisms governing this release and its behavioral relevance are unknown. Here, we show that granule cells express the voltage-gated sodium channel α-subunit NaV1.2 in clusters distributed throughout the cell surface including dendritic spines. Deletion of NaV1.2 in granule cells abolished spiking and GABA release as well as inhibition of synaptically connected mitral cells (MCs). As a consequence, mice required more time to discriminate highly similar odorant mixtures, while odor discrimination learning remained unaffected. In conclusion, we show that expression of NaV1.2 in granule cells is crucial for physiological dendritic GABA release and rapid discrimination of similar odorants with high accuracy. Hence, our data indicate that neurotransmitter-releasing dendritic spines function just like axon terminals. In axonal nerve terminals, neurotransmitter release is triggered by a localized Ca2+ nanodomain generated by voltage-gated calcium channels in response to an action potential, which in turn is mediated by voltage-gated sodium channels. Dendritic neurotransmitter release has been thought to work differently, mainly depending on Ca2+ entering directly through N-methyl-D-aspartate (NMDA) receptors, a subtype of ligand-gated ion channel. To further investigate how dendritic neurotransmitter is released, we studied granule cells in the olfactory bulb of mice, which establish inhibitory dendrodendritic synapses with mitral cells. We show that granule cells express voltage-gated sodium channels predominantly localized in dendrites and spines. Down-regulation of these channels precludes action potential firing in granule cells and strongly reduces mitral cell inhibition. Behaviorally, these mice require more time to discriminate highly similar odorants at maximal accuracy. Therefore, the inhibition of mitral cells relies on neurotransmitter released from the dendrites of granule cells by a mechanism that resembles axonal neurotransmitter release much more than previously thought.
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Affiliation(s)
- Daniel Nunes
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal
- Functional Neuroanatomy Department, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
- * E-mail: (DN); (TK)
| | - Thomas Kuner
- Functional Neuroanatomy Department, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
- * E-mail: (DN); (TK)
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Zhu X, Padmanabhan R, Copeland B, Bridgers J, Ren Z, Kamalakaran S, O'Driscoll-Collins A, Berkovic SF, Scheffer IE, Poduri A, Mei D, Guerrini R, Lowenstein DH, Allen AS, Heinzen EL, Goldstein DB. A case-control collapsing analysis identifies epilepsy genes implicated in trio sequencing studies focused on de novo mutations. PLoS Genet 2017; 13:e1007104. [PMID: 29186148 PMCID: PMC5724893 DOI: 10.1371/journal.pgen.1007104] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 12/11/2017] [Accepted: 11/07/2017] [Indexed: 12/22/2022] Open
Abstract
Trio exome sequencing has been successful in identifying genes with de novo mutations (DNMs) causing epileptic encephalopathy (EE) and other neurodevelopmental disorders. Here, we evaluate how well a case-control collapsing analysis recovers genes causing dominant forms of EE originally implicated by DNM analysis. We performed a genome-wide search for an enrichment of "qualifying variants" in protein-coding genes in 488 unrelated cases compared to 12,151 unrelated controls. These "qualifying variants" were selected to be extremely rare variants predicted to functionally impact the protein to enrich for likely pathogenic variants. Despite modest sample size, three known EE genes (KCNT1, SCN2A, and STXBP1) achieved genome-wide significance (p<2.68×10−6). In addition, six of the 10 most significantly associated genes are known EE genes, and the majority of the known EE genes (17 out of 25) originally implicated in trio sequencing are nominally significant (p<0.05), a proportion significantly higher than the expected (Fisher’s exact p = 2.33×10−17). Our results indicate that a case-control collapsing analysis can identify several of the EE genes originally implicated in trio sequencing studies, and clearly show that additional genes would be implicated with larger sample sizes. The case-control analysis not only makes discovery easier and more economical in early onset disorders, particularly when large cohorts are available, but also supports the use of this approach to identify genes in diseases that present later in life when parents are not readily available. Trio exome sequencing and de novo mutation (DNM) analysis has been the main approach to discovering genes responsible for severe sporadic disorders, including a range of neurodevelopmental disorders. This approach requires sequencing parents, identifying DNMs from trio sequence data, and comparing the observed rate of DNMs to the expected. In this study, we adopted a case-control design, performed a gene-based collapsing analysis, and rediscovered several of the epileptic encephalopathy (EE) genes originally implicated by DNM analysis of EE trios. Our collapsing analysis focused on ultra-rare, highly impactful variants (“qualifying variants”) by filtering against large-scale population datasets, and this approach revealed that most of the standing variation can be filtered out and DNMs are enriched in “qualifying variants”. Our study suggests that a case-control analysis approach can be used to identify disease genes with causal mutations that are predominantly de novo in place of trio-based analysis methods. This offers an efficient and cost effective alternative approach when large-scale trio sequencing is not possible.
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Affiliation(s)
- Xiaolin Zhu
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, United States of America
| | - Raghavendra Padmanabhan
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, United States of America
| | - Brett Copeland
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, United States of America
| | - Joshua Bridgers
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, United States of America
| | - Zhong Ren
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, United States of America
| | - Sitharthan Kamalakaran
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, United States of America
| | | | - Samuel F. Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne at Austin Health, Heidelberg, Australia
| | - Ingrid E. Scheffer
- Epilepsy Research Centre, Department of Medicine, University of Melbourne at Austin Health, Heidelberg, Australia
- Florey Institute for Neuroscience and Mental Health, University of Melbourne, Heidelberg, Australia
- Departments of Paediatrics and Neurology, Royal Children's Hospital, University of Melbourne, Melbourne, Australia
| | - Annapurna Poduri
- Epilepsy Genetics Program and Department of Neurology, Harvard Medical School, Boston, MA, United States of America
| | - Davide Mei
- Pediatric Neurology Unit and Laboratories, Meyer Children’s Hospital, University of Florence, Florence, Italy
| | - Renzo Guerrini
- Pediatric Neurology Unit and Laboratories, Meyer Children’s Hospital, University of Florence, Florence, Italy
- IRCCS Stella Maris Foundation, Pisa, Italy
| | - Daniel H. Lowenstein
- Department of Neurology, University of California, San Francisco, San Francisco, California, United States of America
| | - Andrew S. Allen
- Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina, United States of America
| | - Erin L. Heinzen
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, United States of America
| | - David B. Goldstein
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, United States of America
- Department of Medicine, Royal College of Surgeons in Ireland, St Stephen's Green, Dublin, Ireland
- * E-mail:
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Wang G, Wu L, Chen Z, Sun J. Identification of crucial miRNAs and the targets in renal cortex of hypertensive patients by expression profiles. Ren Fail 2017; 39:92-99. [PMID: 27802793 PMCID: PMC6014400 DOI: 10.1080/0886022x.2016.1244083] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 09/04/2016] [Accepted: 09/16/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUNDS Defect in kidney is one major reason of hypertension. The study aimed ao uncovering the regulatory mechanisms of miRNAs and the targets in hypertensive kidney. METHODS Gene expression profile of GSE28345 and miRNA expression profile of GSE28283 were downloaded from GEO database. After data preprocessing, differently expressed genes (DEGs) and miRNAs (DE-miRs) were identified using limma package. Then targets of miRNAs were predicted according to information in relevant databases. Function and pathway enrichment analyses were performed for DEGs using DAVID software. Furthermore, protein-protein interaction (PPI) networks were constructed for up- and down-regulated genes, respectively, using the Cytoscape. Additionally, for down-regulated DEGs, the integrated regulatory network was established combining PPI network with the miRNA-mRNA interactions. RESULTS As a result, 285 DEGs were identified, including 177 up-regulated and 108 down-regulated genes. Combined with the predicted targets of miRNAs, 22 up-regulated DE-miRs were identified. In the integrated network for down-regulated DEGs, three crucial nodes were identified as ASPN, COL12A1, and SCN2A. ASPN was predicted as target of miR-21 and miR-374b, and COL12A1 was the target of miR-30e, miR-21, and miR-195, while SCN2A was the target of miR-30e, miR-374b, and miR-195. Notably, COL12A1 and ASPN were linked with each other in the network. CONCLUSION Three crucial genes were identified in hypertensive kidney, such as COL12A1, ASPN, and SCN2A. ASPN might co-function with COL12A1, and they both might be the targets of miR-21. SCN2A might be a novel target of miR-30e and miR-374b. However, more experiments are needed to validate these results.
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Affiliation(s)
- Guohua Wang
- Department of Pediatrics, The First Hospital of Jilin University, Changchun, China
| | - Lan Wu
- Department of Pediatrics, The First Hospital of Jilin University, Changchun, China
| | - Zhi Chen
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China
| | - Jinghui Sun
- Department of Pediatrics, The First Hospital of Jilin University, Changchun, China
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Ben-Shalom R, Keeshen CM, Berrios KN, An JY, Sanders SJ, Bender KJ. Opposing Effects on Na V1.2 Function Underlie Differences Between SCN2A Variants Observed in Individuals With Autism Spectrum Disorder or Infantile Seizures. Biol Psychiatry 2017; 82:224-232. [PMID: 28256214 PMCID: PMC5796785 DOI: 10.1016/j.biopsych.2017.01.009] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/14/2016] [Accepted: 01/10/2017] [Indexed: 01/02/2023]
Abstract
BACKGROUND Variants in the SCN2A gene that disrupt the encoded neuronal sodium channel NaV1.2 are important risk factors for autism spectrum disorder (ASD), developmental delay, and infantile seizures. Variants observed in infantile seizures are predominantly missense, leading to a gain of function and increased neuronal excitability. How variants associated with ASD affect NaV1.2 function and neuronal excitability are unclear. METHODS We examined the properties of 11 ASD-associated SCN2A variants in heterologous expression systems using whole-cell voltage-clamp electrophysiology and immunohistochemistry. Resultant data were incorporated into computational models of developing and mature cortical pyramidal cells that express NaV1.2. RESULTS In contrast to gain of function variants that contribute to seizure, we found that all ASD-associated variants dampened or eliminated channel function. Incorporating these electrophysiological results into a compartmental model of developing excitatory neurons demonstrated that all ASD variants, regardless of their mechanism of action, resulted in deficits in neuronal excitability. Corresponding analysis of mature neurons predicted minimal change in neuronal excitability. CONCLUSIONS This functional characterization thus identifies SCN2A mutation and NaV1.2 dysfunction as the most frequently observed ASD risk factor detectable by exome sequencing and suggests that associated changes in neuronal excitability, particularly in developing neurons, may contribute to ASD etiology.
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Affiliation(s)
- Roy Ben-Shalom
- Center for Integrative Neuroscience, Kavli Institute for Fundamental Neuroscience, Department of Neurology, San Francisco, San Francisco; Computational Research Division , Lawrence Berkeley National Laboratory, Berkeley, California
| | - Caroline M Keeshen
- Center for Integrative Neuroscience, Kavli Institute for Fundamental Neuroscience, Department of Neurology, San Francisco, San Francisco
| | - Kiara N Berrios
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico
| | - Joon Y An
- Department of Psychiatry, San Francisco, San Francisco; UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco
| | - Stephan J Sanders
- Department of Psychiatry, San Francisco, San Francisco; UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco
| | - Kevin J Bender
- Center for Integrative Neuroscience, Kavli Institute for Fundamental Neuroscience, Department of Neurology, San Francisco, San Francisco; UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco; Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico.
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Li T, Lu G, Chiang EY, Chernov-Rogan T, Grogan JL, Chen J. High-throughput electrophysiological assays for voltage gated ion channels using SyncroPatch 768PE. PLoS One 2017; 12:e0180154. [PMID: 28683073 PMCID: PMC5500279 DOI: 10.1371/journal.pone.0180154] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/09/2017] [Indexed: 01/08/2023] Open
Abstract
Ion channels regulate a variety of physiological processes and represent an important class of drug target. Among the many methods of studying ion channel function, patch clamp electrophysiology is considered the gold standard by providing the ultimate precision and flexibility. However, its utility in ion channel drug discovery is impeded by low throughput. Additionally, characterization of endogenous ion channels in primary cells remains technical challenging. In recent years, many automated patch clamp (APC) platforms have been developed to overcome these challenges, albeit with varying throughput, data quality and success rate. In this study, we utilized SyncroPatch 768PE, one of the latest generation APC platforms which conducts parallel recording from two-384 modules with giga-seal data quality, to push these 2 boundaries. By optimizing various cell patching parameters and a two-step voltage protocol, we developed a high throughput APC assay for the voltage-gated sodium channel Nav1.7. By testing a group of Nav1.7 reference compounds’ IC50, this assay was proved to be highly consistent with manual patch clamp (R > 0.9). In a pilot screening of 10,000 compounds, the success rate, defined by > 500 MΩ seal resistance and >500 pA peak current, was 79%. The assay was robust with daily throughput ~ 6,000 data points and Z’ factor 0.72. Using the same platform, we also successfully recorded endogenous voltage-gated potassium channel Kv1.3 in primary T cells. Together, our data suggest that SyncroPatch 768PE provides a powerful platform for ion channel research and drug discovery.
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Affiliation(s)
- Tianbo Li
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., South San Francisco, California, United States of America
- * E-mail: (TL); (JC)
| | - Gang Lu
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., South San Francisco, California, United States of America
| | - Eugene Y. Chiang
- Department of Cancer Immunology, Genentech Inc., South San Francisco, California, United States of America
| | - Tania Chernov-Rogan
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., South San Francisco, California, United States of America
| | - Jane L. Grogan
- Department of Cancer Immunology, Genentech Inc., South San Francisco, California, United States of America
| | - Jun Chen
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., South San Francisco, California, United States of America
- * E-mail: (TL); (JC)
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Andoh M, Ikegaya Y, Koyama R. [Autism spectrum disorders and epilepsy]. Nihon Yakurigaku Zasshi 2016; 148:121-122. [PMID: 27478051 DOI: 10.1254/fpj.148.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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Carroll LS, Woolf R, Ibrahim Y, Williams HJ, Dwyer S, Walters J, Kirov G, O'Donovan MC, Owen MJ. Mutation screening of SCN2A in schizophrenia and identification of a novel loss-of-function mutation. Psychiatr Genet 2016; 26:60-5. [PMID: 26555645 PMCID: PMC4756433 DOI: 10.1097/ypg.0000000000000110] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVES There is a growing body of evidence suggesting a shared genetic susceptibility between many neuropsychiatric disorders, including schizophrenia, autism, intellectual disability (ID) and epilepsy. The sodium channel, voltage-gated type II α subunit gene SCN2A has been shown to exhibit loss-of-function (LoF) mutations in individuals with seizure disorders, ID, autism and schizophrenia. The role of LoF mutations in schizophrenia is still uncertain with only one such mutation identified to date. METHODS To seek additional evidence for a role for LoF mutations at SCN2A in schizophrenia we performed mutation screening of the entire coding sequence in 980 schizophrenia cases. Given an absence of LoF mutations in a public exome cohort (ESP6500, N=6503), we did not additionally sequence controls. RESULTS We identified a novel, nonsense (i.e. stop codon) mutation in one case (E169X) that is absent in 4300 European-American and 2203 African-American individuals from the NHLBI Exome Sequencing Project. This is the second LoF allele identified in a schizophrenia case to date. We also show a novel, missense variant, V1282F, that occurs in two cases and is absent in the control dataset. CONCLUSION We argue that very rare, LoF mutations at SCN2A act in a moderately penetrant manner to increase the risk of developing several neuropsychiatric disorders including seizure disorders, ID, autism and schizophrenia.
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Affiliation(s)
- Liam S Carroll
- MRC Centre for Neuropsychiatric Genetics and Genomics, Department of Psychological Medicine & Neurology, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK
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Horvath GA, Demos M, Shyr C, Matthews A, Zhang L, Race S, Stockler-Ipsiroglu S, Van Allen MI, Mancarci O, Toker L, Pavlidis P, Ross CJ, Wasserman WW, Trump N, Heales S, Pope S, Cross JH, van Karnebeek CDM. Secondary neurotransmitter deficiencies in epilepsy caused by voltage-gated sodium channelopathies: A potential treatment target? Mol Genet Metab 2016; 117:42-8. [PMID: 26647175 DOI: 10.1016/j.ymgme.2015.11.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/16/2015] [Accepted: 11/16/2015] [Indexed: 12/26/2022]
Abstract
We describe neurotransmitter abnormalities in two patients with drug-resistant epilepsy resulting from deleterious de novo mutations in sodium channel genes. Whole exome sequencing identified a de novo SCN2A splice-site mutation (c.2379+1G>A, p.Glu717Gly.fs*30) resulting in deletion of exon 14, in a 10-year old male with early onset global developmental delay, intermittent ataxia, autism, hypotonia, epileptic encephalopathy and cerebral/cerebellar atrophy. In the cerebrospinal fluid both homovanillic acid and 5-hydroxyindoleacetic acid were significantly decreased; extensive biochemical and genetic investigations ruled out primary neurotransmitter deficiencies and other known inborn errors of metabolism. In an 8-year old female with an early onset intractable epileptic encephalopathy, developmental regression, and progressive cerebellar atrophy, a previously unreported de novo missense mutation was identified in SCN8A (c.5615G>A; p.Arg1872Gln), affecting a highly conserved residue located in the C-terminal of the Nav1.6 protein. Aside from decreased homovanillic acid and 5-hydroxyindoleacetic acid, 5-methyltetrahydrofolate was also found to be low. We hypothesize that these channelopathies cause abnormal synaptic mono-amine metabolite secretion/uptake via impaired vesicular release and imbalance in electrochemical ion gradients, which in turn aggravate the seizures. Treatment with oral 5-hydroxytryptophan, l-Dopa/Carbidopa, and a dopa agonist resulted in mild improvement of seizure control in the male case, most likely via dopamine and serotonin receptor activated signal transduction and modulation of glutamatergic, GABA-ergic and glycinergic neurotransmission. Neurotransmitter analysis in other sodium channelopathy patients will help validate our findings, potentially yielding novel treatment opportunities.
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Affiliation(s)
- Gabriella A Horvath
- Division of Biochemical Diseases, Dept of Pediatrics, B.C. Children's Hospital, University of British Columbia, Vancouver, Canada
| | - Michelle Demos
- Div. of Pediatric Neurology, Dept of Pediatrics, B.C. Children's Hospital, University of British Columbia, Vancouver, Canada
| | - Casper Shyr
- Center for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Allison Matthews
- Center for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Linhua Zhang
- Center for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, Canada
| | - Simone Race
- Division of Biochemical Diseases, Dept of Pediatrics, B.C. Children's Hospital, University of British Columbia, Vancouver, Canada
| | - Sylvia Stockler-Ipsiroglu
- Division of Biochemical Diseases, Dept of Pediatrics, B.C. Children's Hospital, University of British Columbia, Vancouver, Canada
| | - Margot I Van Allen
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Ogan Mancarci
- Department of Psychiatry and Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Lilah Toker
- Department of Psychiatry and Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Paul Pavlidis
- Department of Psychiatry and Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Colin J Ross
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Wyeth W Wasserman
- Center for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Natalie Trump
- Molecular Genetics, Great Ormond Street Hospital for Children, London, United Kingdom
| | - Simon Heales
- Neurometabolic Unit, National Hospital, Queen Square, London, United Kindgdom; Chemical Pathology, Great Ormond Street Hospital, UCL Institute of Child Health, London, United Kingdom
| | - Simon Pope
- Neurometabolic Unit, National Hospital, Queen Square, London, United Kindgdom
| | - J Helen Cross
- Developmental Neurosciences Programme, UCL Institute of Child Health, and Great Ormond Street Hospital for Children, London, United Kingdom
| | - Clara D M van Karnebeek
- Division of Biochemical Diseases, Dept of Pediatrics, B.C. Children's Hospital, University of British Columbia, Vancouver, Canada; Center for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, Canada.
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Abstract
Daphnia pulex is a widely used toxicological model and is known for its sensitivity to cadmium (Cd). Recent research suggests that microRNAs (miRNAs) play a critical role in animal responses to heavy metals. To investigate the functions of D. pulex miRNAs under Cd exposure, we analyzed the miRNA profiles of D. pulex after 48 h using miRNA microarrays and validated our findings by q-PCR. miRNA dpu-let-7 was identified as a stably expressed gene and used as a reference. We identified 22 and 21 differentially expressed miRNAs under low (20 μg/L CdCl2) and high-exposure (40 μg/L CdCl2) concentrations compared to controls, respectively. Cellular functions of predicted miRNA target Cd-responsive genes included oxidative stress, ion transport, mitochondrial damage, and DNA repair. An insulin-related network was also identified in relation to several Cd-responsive miRNAs. The expression of three predicted target genes for miR-71 and miR-210 were evaluated, and expression of two of them (SCN2A and SLC31A1) was negatively correlated with the expression of their regulator miRNAs. We show miR-210 is hypoxia-responsive in D. pulex and propose Cd and hypoxia induce miR-210 via a same HIF1α modulated pathway. Collectively, this research advances our understanding on the role of miRNAs in response to heavy-metal exposure.
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Affiliation(s)
- Shuai Chen
- Department of Forestry and Natural Resources, Purdue University , West Lafayette, Indiana, 47907 United States
| | - Garrett J McKinney
- School of Aquatic and Fishery Sciences, University of Washington , Seattle, Washington, 98195 United States
| | - Krista M Nichols
- Department of Forestry and Natural Resources, Purdue University , West Lafayette, Indiana, 47907 United States
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Ocean and Atmospheric Administration , Seattle, Washington, 98112 United States
| | - John K Colbourne
- Environmental Genomics Group, School of Biosciences, University of Birmingham , Edgbaston, Birmingham B15 2TT, U.K
| | - Maria S Sepúlveda
- Department of Forestry and Natural Resources, Purdue University , West Lafayette, Indiana, 47907 United States
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D'Gama AM, Pochareddy S, Li M, Jamuar SS, Reiff RE, Lam ATN, Sestan N, Walsh CA. Targeted DNA Sequencing from Autism Spectrum Disorder Brains Implicates Multiple Genetic Mechanisms. Neuron 2015; 88:910-917. [PMID: 26637798 PMCID: PMC4672379 DOI: 10.1016/j.neuron.2015.11.009] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/16/2015] [Accepted: 10/27/2015] [Indexed: 11/18/2022]
Abstract
Single nucleotide variants (SNVs), particularly loss-of-function mutations, are significant contributors to autism spectrum disorder (ASD) risk. Here we report the first systematic deep sequencing study of 55 postmortem ASD brains for SNVs in 78 known ASD candidate genes. Remarkably, even without parental samples, we find more ASD brains with mutations that are protein-altering (26/55 cases versus 12/50 controls, p = 0.015), deleterious (16/55 versus 5/50, p = 0.016), or loss-of-function (6/55 versus 0/50, p = 0.028) compared to controls, with recurrent deleterious mutations in ARID1B, SCN1A, SCN2A, and SETD2, suggesting these mutations contribute to ASD risk. In several cases, the identified mutations and medical records suggest syndromic ASD diagnoses. Two ASD and one Fragile X premutation case showed deleterious somatic mutations, providing evidence that somatic mutations occur in ASD cases, and supporting a model in which a combination of germline and/or somatic mutations may contribute to ASD risk on a case-by-case basis.
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Affiliation(s)
- Alissa M D'Gama
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Sirisha Pochareddy
- Departments of Neuroscience, Genetics, and Psychiatry, and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | - Mingfeng Li
- Departments of Neuroscience, Genetics, and Psychiatry, and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | - Saumya S Jamuar
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Paediatrics, KK Women's and Children's Hospital, Singapore; Paediatrics Academic Clinical Programme, Duke-NUS Graduate School of Medicine, Singapore
| | - Rachel E Reiff
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Anh-Thu N Lam
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Nenad Sestan
- Departments of Neuroscience, Genetics, and Psychiatry, and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | - Christopher A Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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Magdaleno-Méndez A, Domínguez B, Rodríguez-Andrade A, Barrientos-Morales M, Cervantes-Acosta P, Hernández-Beltrán A, González-Ramírez R, Felix R. Ghrelin increases growth hormone production and functional expression of NaV1.1 and Na V1.2 channels in pituitary somatotropes. Endocrine 2015; 48:929-36. [PMID: 25151402 DOI: 10.1007/s12020-014-0392-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/11/2014] [Indexed: 12/19/2022]
Abstract
A variety of ion channels are expressed in the plasma membrane of somatotropes within the anterior pituitary gland. Modification of these channels is linked to intracellular Ca2+ levels and therefore to hormone secretion. Previous investigations have shown that the gut-derived orexigenic peptide hormone ghrelin and synthetic GH-releasing peptides (GHRPs) stimulate release of growth hormone (GH) and increase the number of functional voltage-gated Ca2+ and Na+ channels in the membrane of clonal GC somatotropes. Here, we reveal that chronic treatment with ghrelin and its synthetic analog GHRP-6 also increases GH release from bovine pituitary somatotropes in culture, and that this action is associated with a significant increase in Na+ macroscopic current. Consistent with this, Na+ current blockade with tetrodotoxin (TTX) abolished the ghrelin- and GHRP-6-induced increase in GH release. Furthermore, semi-quantitative and real-time RT-PCR analysis revealed an upregulation in the transcript levels of GH, as well as of NaV1.1 and NaV1.2, two isoforms of TTX-sensitive Na+ channels expressed in somatotropes, after treatment with ghrelin or GHRP-6. These findings improve our knowledge on (i) the cellular mechanisms involved in the control of GH secretion, (ii) the molecular diversity of Na+ channels in pituitary somatotropes, and (iii) the regulation of GH and Na+ channel gene expression by ghrelin and GHRPs.
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Affiliation(s)
- Adasue Magdaleno-Méndez
- Laboratory of Cell Biology, School of Veterinary Medicine and Animal Science, University of Veracruz, Circunvalación esquina Yáñez s/n, C.P. 91710, Veracruz, Mexico
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Abstract
Cinobufagin and resibufogenin are two major effective bufadienolides of Chan su (toad venom), which is a Chinese medicine obtained from the skin venom gland of toads and is used as a cardiotonic and central nervous system (CNS) respiratory agent, an analgesic and anesthetic, and as a remedy for ulcers. Many clinical cases showed that Chan su has severe side-effects on the CNS, causing shortness of breath, breathlessness, seizure, coma and cardiac arrhythmia. We used whole-cell recordings from brain slices to determine the effects of bufadienolides on excitability of a principal neuron in main olfactory bulb (MOB), mitral cells (MCs), and the cellular mechanism underlying the excitation. At higher concentrations, cinobufagin and resibufogenin induced irreversible over-excitation of MCs indicating a toxic effect. At lower concentrations, they concentration-dependently increased spontaneous firing rate, depolarized the membrane potential of MCs, and elicited inward currents. The excitatory effects were due to a direct action on MCs rather than an indirect phasic action. Bufadienolides and ouabain had similar effects on firing of MCs which suggested that bufadienolides activated neuron through a ouabain-like effect, most likely by inhibiting Na+/K+-ATPase. The direct action of bufadienolide on brain Na+ channels was tested by recordings from stably Nav1.2-transfected cells. Bufadienolides failed to make significant changes of the main properties of Nav1.2 channels in current amplitude, current-voltage (I-V) relationships, activation and inactivation. Our results suggest that inhibition of Na+/K+-ATPase may be involved in both the pharmacological and toxic effects of bufadienolide-evoked CNS excitation.
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Affiliation(s)
- Ze-Jun Wang
- Department of Anatomy, College of Medicine, Howard University, Washington, DC, United States of America
- * E-mail: (ZW); (TH)
| | - Liqin Sun
- Department of Anatomy, College of Medicine, Howard University, Washington, DC, United States of America
| | - Thomas Heinbockel
- Department of Anatomy, College of Medicine, Howard University, Washington, DC, United States of America
- * E-mail: (ZW); (TH)
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Li T, Tian C, Scalmani P, Frassoni C, Mantegazza M, Wang Y, Yang M, Wu S, Shu Y. Action potential initiation in neocortical inhibitory interneurons. PLoS Biol 2014; 12:e1001944. [PMID: 25203314 PMCID: PMC4159120 DOI: 10.1371/journal.pbio.1001944] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 07/31/2014] [Indexed: 01/22/2023] Open
Abstract
Sodium channels add variety to inhibitory interneurons Different populations of inhibitory interneurons in the cerebral cortex express distinct subtypes of sodium channels, resulting in diverse action potential thresholds and network excitability. Action potential (AP) generation in inhibitory interneurons is critical for cortical excitation-inhibition balance and information processing. However, it remains unclear what determines AP initiation in different interneurons. We focused on two predominant interneuron types in neocortex: parvalbumin (PV)- and somatostatin (SST)-expressing neurons. Patch-clamp recording from mouse prefrontal cortical slices showed that axonal but not somatic Na+ channels exhibit different voltage-dependent properties. The minimal activation voltage of axonal channels in SST was substantially higher (∼7 mV) than in PV cells, consistent with differences in AP thresholds. A more mixed distribution of high- and low-threshold channel subtypes at the axon initial segment (AIS) of SST cells may lead to these differences. Surprisingly, NaV1.2 was found accumulated at AIS of SST but not PV cells; reducing NaV1.2-mediated currents in interneurons promoted recurrent network activity. Together, our results reveal the molecular identity of axonal Na+ channels in interneurons and their contribution to AP generation and regulation of network activity. Inhibitory interneurons in the cerebral cortex are diverse in many respects. Here, we examine whether this diversity extends to the composition of ion channels along the axon, which might determine the neurons' excitability. We performed patch-clamp recordings from cortical interneuron axons in brain slices obtained from two transgenic mouse lines. In each mouse line, distinct populations of inhibitory interneurons—those that express parvalbumin (PV) or those that express somatostatin (SST)—were labeled with green fluorescent protein to allow visualization. We show that action potentials initiate at the axon initial segment (a specialized region of the axon closest to the cell body) in both cell types, but SST neurons have a higher action potential threshold than PV neurons because their sodium channels require a greater degree of depolarization to be fully activated. At the molecular level, we found that the population of sodium channels in SST neurons requires a larger depolarization because it has a more mixed composition of high- and low-threshold sodium channel subtypes. In summary, this study reveals diversity in the molecular identity and voltage dependence of sodium channels that are responsible for initiating action potentials in different populations of interneurons. In addition, the presence of a particular subtype of sodium channel—NaV1.2—in inhibitory interneurons might explain why loss-of-function mutations in this channel result in epilepsy.
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Affiliation(s)
- Tun Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai, China
| | - Cuiping Tian
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai, China
| | - Paolo Scalmani
- U.O. of Neurophysiopathology and Diagnostic Epileptology, Foundation Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Neurological Institute Carlo Besta, Milano, Italy
| | - Carolina Frassoni
- U.O. of Clinical Epileptology and Experimental Neurophysiology, Foundation Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Neurological Institute Carlo Besta, Milano, Italy
| | - Massimo Mantegazza
- Institute of Molecular and Cellular Pharmacology (IPMC), Laboratory of Excellence Ion Channel Science and Therapeutics (LabEx ICST), CNRS UMR7275 and University of Nice-Sophia Antipolis, Valbonne, France
| | - Yonghong Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai, China
| | - Mingpo Yang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai, China
| | - Si Wu
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, School of Brain and Cognitive Sciences, Beijing Normal University, Beijing, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, China
| | - Yousheng Shu
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, School of Brain and Cognitive Sciences, Beijing Normal University, Beijing, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, China
- * E-mail:
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