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Steele JW, Krishnan V, Finnell RH. Mechanisms of neurodevelopmental toxicity of topiramate. Crit Rev Toxicol 2024; 54:465-475. [PMID: 38995641 PMCID: PMC11296906 DOI: 10.1080/10408444.2024.2368552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/03/2024] [Accepted: 06/11/2024] [Indexed: 07/13/2024]
Abstract
Prescriptions for antiseizure medications (ASMs) have been rapidly growing over the last several decades due, in part, to an expanding list of clinical indications for which they are now prescribed. This trend has raised concern for potential adverse neurodevelopmental outcomes in ASM-exposed pregnancies. Recent large scale population studies have suggested that the use of topiramate (TOPAMAX, Janssen-Cilag), when prescribed for seizure control, migraines, and/or weight management, is associated with an increased risk for autism spectrum disorder (ASD), intellectual disability, and attention-deficit/hyperactivity disorder (ADHD) in exposed offspring. Here, we critically review epidemiologic evidence demonstrating the neurobehavioral teratogenicity of topiramate and speculate on the neuromolecular mechanisms by which prenatal exposure may perturb neurocognitive development. Specifically, we explore the potential role of topiramate's pharmacological interactions with ligand- and voltage-gated ion channels, especially GABAergic signaling, its effects on DNA methylation and histone acetylation, whether topiramate induces oxidative stress, and its association with fetal growth restriction as possible mechanisms contributing to neurodevelopmental toxicity. Resolving this biology will be necessary to reduce the risk of adverse pregnancy outcomes caused by topiramate or other ASMs.
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Affiliation(s)
- John W. Steele
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Vaishnav Krishnan
- Departments of Neurology, Neuroscience and Psychiatry, and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Richard H. Finnell
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA
- Departments of Molecular and Cellular Biology and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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2
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Guo Y, Liu C, Qi F, Chen C, Gao Z, Zhang H. Split intein converting peptide protein interaction into electrochemically assisted metal ion catalytic signal in the prenatal screening of pediatric epilepsy. Bioelectrochemistry 2024; 160:108754. [PMID: 38889537 DOI: 10.1016/j.bioelechem.2024.108754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/22/2024] [Accepted: 06/01/2024] [Indexed: 06/20/2024]
Abstract
Dravet syndrome is a rare form of epilepsy starting from infancy that can plaque the affected individuals all though his/her life with repeated seizures, and this condition is currently without a complete cure. So prenatal screening of molecular markers of this condition is urgently needed to help couples conceiving new lives to steer clear of this potential danger. And such an assay should ideally be of low cost and could be completed in a point-of-care fashion. This work reports an attempt to construct such an assay using simple peptides in the place of conventional biosensing macro-molecules such as antibodies and enzymes. Specifically, a marker protein of this syndrome can bring the two pieces of a self-splitting peptide "intein" together, which in turn facilitate the formation of metal ion coordination site, recruiting cupric ion to generate catalytically amplified signal readout. Using this method, disease marker protein Nav of this syndrome can be quantitatively detected directly in amniotic fluid samples, and samples associated with potential risk factors such as family history of this syndrome shows statistically evident decrease of this marker protein. These results may promise future application of the proposed method in clinical practice to reduce the social burden of Dravet syndrome by reducing its actual incident rate.
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Affiliation(s)
- Yujie Guo
- Department of Epilepsy Center, Children's Hospital Affiliated to Shandong University, No. 23976 Jingshi Road, 250022, Jinan, China
| | - Chen Liu
- Neonatology department, Children's Hospital Affiliated to Shandong University, No. 23976 Jingshi Road, 250022, Jinan, China
| | - Fang Qi
- Department of Epilepsy Center, Children's Hospital Affiliated to Shandong University, No. 23976 Jingshi Road, 250022, Jinan, China
| | - Chuanmei Chen
- Department of Epilepsy Center, Children's Hospital Affiliated to Shandong University, No. 23976 Jingshi Road, 250022, Jinan, China
| | - Zaifen Gao
- Department of Epilepsy Center, Children's Hospital Affiliated to Shandong University, No. 23976 Jingshi Road, 250022, Jinan, China.
| | - Haiyan Zhang
- Department of Epilepsy Center, Children's Hospital Affiliated to Shandong University, No. 23976 Jingshi Road, 250022, Jinan, China.
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3
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Ng ACH, Chahine M, Scantlebury MH, Appendino JP. Channelopathies in epilepsy: an overview of clinical presentations, pathogenic mechanisms, and therapeutic insights. J Neurol 2024; 271:3063-3094. [PMID: 38607431 DOI: 10.1007/s00415-024-12352-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
Pathogenic variants in genes encoding ion channels are causal for various pediatric and adult neurological conditions. In particular, several epilepsy syndromes have been identified to be caused by specific channelopathies. These encompass a spectrum from self-limited epilepsies to developmental and epileptic encephalopathies spanning genetic and acquired causes. Several of these channelopathies have exquisite responses to specific antiseizure medications (ASMs), while others ASMs may prove ineffective or even worsen seizures. Some channelopathies demonstrate phenotypic pleiotropy and can cause other neurological conditions outside of epilepsy. This review aims to provide a comprehensive exploration of the pathophysiology of seizure generation, ion channels implicated in epilepsy, and several genetic epilepsies due to ion channel dysfunction. We outline the clinical presentation, pathogenesis, and the current state of basic science and clinical research for these channelopathies. In addition, we briefly look at potential precision therapy approaches emerging for these disorders.
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Affiliation(s)
- Andy Cheuk-Him Ng
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Division of Neurology, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta and Stollery Children's Hospital, Edmonton, AB, Canada
| | - Mohamed Chahine
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
- CERVO, Brain Research Centre, Quebec City, Canada
| | - Morris H Scantlebury
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Calgary, Canada
| | - Juan P Appendino
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada.
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Romero VI, Sáenz S, Arias-Almeida B, DiCapua D, Hosomichi K. AARS and CACNA1A mutations: diagnostic insights into a case report of uncommon epileptic encephalopathy phenotypes in two siblings. Front Neurol 2024; 15:1376643. [PMID: 38689878 PMCID: PMC11059961 DOI: 10.3389/fneur.2024.1376643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 04/04/2024] [Indexed: 05/02/2024] Open
Abstract
Epilepsy, characterized by recurrent seizures, impacts 70-80% of patients, leading to cognitive deficits. The intricate relationship between seizure control and cognitive impairment remains complex. Epileptic encephalopathy (EE), an intensified form often rooted in genetic factors, is detectable through next-generation sequencing, aiding in precise diagnoses, family counseling, and potential treatment strategies. We present a case involving two sisters with refractory generalized seizures evolving into dysarthria, dysphagia, ataxia, and cognitive decline. Despite normal physical exams, abnormal electroencephalogram results consistent with epilepsy were noted. Whole Exome Sequencing identified heterozygous variants in the alanyl-tRNA synthetase (AARS) and Calcium Voltage-Gated Channel Subunit Alpha 1 (CACNA1A) genes. The AARS variant (c.C2083T, p.R695*) was maternal, while the CACNA1A variant (c.G7400C, p.R2467P) was paternal. Patients A and B exhibited a unique blend of neurological and psychiatric conditions, distinct from common disorders that begin adolescence, like Juvenile Myoclonic Epilepsy. Whole Exome Sequencing uncovered an AARS gene and CACNA1A gene, linked to various autosomal dominant phenotypes. Presence in both parents, coupled with familial reports of migraines and seizures, provides insight into accelerated symptom progression. This study underscores the importance of genetic testing in decoding complex phenotypes and emphasizes the value of documenting family history for anticipating related symptoms and future health risks.
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Affiliation(s)
- Vanessa I. Romero
- School of Medicine, Universidad San Francisco de Quito, Quito, Ecuador
| | - Samantha Sáenz
- School of Medicine, Universidad San Francisco de Quito, Quito, Ecuador
| | | | - Daniela DiCapua
- School of Medicine, Universidad San Francisco de Quito, Quito, Ecuador
- Neurology Service, Hospital de Especialidades Eugenio Espejo, Quito, Ecuador
| | - Kazuyoshi Hosomichi
- Laboratory of Computational Genomics, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
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Qu G, Merchant JP, Clatot J, DeFlitch LM, Frederick DJ, Tang S, Salvatore M, Zhang X, Li J, Anderson SA, Goldberg EM. Targeted blockade of aberrant sodium current in a stem cell-derived neuron model of SCN3A encephalopathy. Brain 2024; 147:1247-1263. [PMID: 37935051 PMCID: PMC10994535 DOI: 10.1093/brain/awad376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 09/30/2023] [Accepted: 10/20/2023] [Indexed: 11/09/2023] Open
Abstract
Missense variants in SCN3A encoding the voltage-gated sodium (Na+) channel α subunit Nav1.3 are associated with SCN3A-related neurodevelopmental disorder (SCN3A-NDD), a spectrum of disease that includes epilepsy and malformation of cortical development. How genetic variation in SCN3A leads to pathology remains unclear, as prior electrophysiological work on disease-associated variants has been performed exclusively in heterologous cell systems. To further investigate the mechanisms of SCN3A-NDD pathogenesis, we used CRISPR/Cas9 gene editing to modify a control human induced pluripotent stem cell (iPSC) line to express the recurrent de novo missense variant SCN3A c.2624T>C (p.Ile875Thr). With the established Ngn2 rapid induction protocol, we generated glutamatergic forebrain-like neurons (iNeurons), which we showed to express SCN3A mRNA and Nav1.3-mediated Na+ currents. We performed detailed whole-cell patch clamp recordings to determine the effect of the SCN3A-p.Ile875Thr variant on endogenous Na+ currents in, and intrinsic excitability of, human neurons. Compared to control iNeurons, variant-expressing iNeurons exhibit markedly increased slowly-inactivating/persistent Na+ current, abnormal firing patterns with paroxysmal bursting and plateau-like potentials with action potential failure, and a hyperpolarized voltage threshold for action potential generation. We then validated these findings using a separate iPSC line generated from a patient harbouring the SCN3A-p.Ile875Thr variant compared to a corresponding CRISPR-corrected isogenic control line. Finally, we found that application of the Nav1.3-selective blocker ICA-121431 normalizes action potential threshold and aberrant firing patterns in SCN3A-p.Ile1875Thr iNeurons; in contrast, consistent with action as a Na+ channel blocker, ICA-121431 decreases excitability of control iNeurons. Our findings demonstrate that iNeurons can model the effects of genetic variation in SCN3A yet reveal a complex relationship between gain-of-function at the level of the ion channel versus impact on neuronal excitability. Given the transient expression of SCN3A in the developing human nervous system, selective blockade or suppression of Nav1.3-containing Na+ channels could represent a therapeutic approach towards SCN3A-NDD.
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Affiliation(s)
- Guojie Qu
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Julie P Merchant
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Jérôme Clatot
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Leah M DeFlitch
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Danny J Frederick
- Department of Child and Adolescent Psychiatry, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Sheng Tang
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Madeleine Salvatore
- Department of Child and Adolescent Psychiatry, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Xiaohong Zhang
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Jianping Li
- Department of Child and Adolescent Psychiatry, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Stewart A Anderson
- The Epilepsy NeuroGenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Child and Adolescent Psychiatry, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Ethan M Goldberg
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
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6
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Kwan R, Das P, Gerrebos N, Li J, Wang XY, DeBoer G, Emnacen-Pankhurst V, Lin S, Feng R, Goodchild S, Sojo LE. Development and application of a multiple reaction monitoring method for the simultaneous quantification of sodium channels Na v 1.1, Na v 1.2, and Na v 1.6 in solubilized membrane proteins from stable HEK293 cell lines, rodents, and human brain tissues. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9672. [PMID: 38211346 DOI: 10.1002/rcm.9672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/13/2023] [Accepted: 10/22/2023] [Indexed: 01/13/2024]
Abstract
RATIONALE Nav 1.1, 1.2, and 1.6 are transmembrane proteins acting as voltage-gated sodium channels implicated in various forms of epilepsy. There is a need for knowing their actual concentration in target tissues during drug development. METHODS Unique peptides for Nav 1.1, Nav 1.2, and Nav 1.6 were selected as quantotropic peptides for each protein and used for their quantification in membranes from stably transfected HEK293 cells and rodent and human brain samples using ultra-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. RESULTS Nav 1.1, 1.2, and 1.6 protein expressions in three stably individually transfected HEK293 cell lines were found to be 2.1 ± 0.2, 6.4 ± 1.2, and 4.0 ± 0.6 fmol/μg membrane protein, respectively. In brains, Nav 1.2 showed the highest expression, with approximately three times higher (P < 0.003) in rodents than in humans at 3.05 ± 0.57, with 3.35 ± 0.56 in mouse and rat brains and 1.09 ± 0.27 fmol/μg in human brain. Both Nav 1.1 and 1.6 expressions were much lower in the brains, with approximately 40% less expression in human Nav 1.1 than rodent Nav 1.1 at 0.49 ± 0.1 (mouse), 0.43 ± 0.3 (rat), and 0.28 ± 0.04 (humans); whereas Nav 1.6 had approximately 60% less expression in humans than rodents at 0.27 ± 0.09 (mouse), 0.26 ± 0.06 (rat), and 0.11 ± 0.02 (humans) fmol/μg membrane proteins. CONCLUSIONS Multiple reaction monitoring was used to quantify sodium channels Nav 1.1, 1.2, and 1.6 expressed in stably transfected HEK293 cells and brain tissues from mice, rats, and humans. We found significant differences in the expression of these channels in mouse, rat, and human brains. Nav expression ranking among the three species was Nav 1.2 ≫ Nav 1.1 > Nav 1.6, with the human brain expressing much lower concentrations overall compared to rodent brain.
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Affiliation(s)
- Rainbow Kwan
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
| | - Prerna Das
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
| | - Neelan Gerrebos
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
| | - Jenny Li
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
| | - Xin Yin Wang
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
| | - Gina DeBoer
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
| | | | - Sophia Lin
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
| | - Raymond Feng
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
| | - Sam Goodchild
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
| | - Luis E Sojo
- Xenon Pharmaceuticals Inc., Burnaby, British Columbia, Canada
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7
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Clatot J, Currin CB, Liang Q, Pipatpolkai T, Massey SL, Helbig I, Delemotte L, Vogels TP, Covarrubias M, Goldberg EM. A structurally precise mechanism links an epilepsy-associated KCNC2 potassium channel mutation to interneuron dysfunction. Proc Natl Acad Sci U S A 2024; 121:e2307776121. [PMID: 38194456 PMCID: PMC10801864 DOI: 10.1073/pnas.2307776121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/17/2023] [Indexed: 01/11/2024] Open
Abstract
De novo heterozygous variants in KCNC2 encoding the voltage-gated potassium (K+) channel subunit Kv3.2 are a recently described cause of developmental and epileptic encephalopathy (DEE). A de novo variant in KCNC2 c.374G > A (p.Cys125Tyr) was identified via exome sequencing in a patient with DEE. Relative to wild-type Kv3.2, Kv3.2-p.Cys125Tyr induces K+ currents exhibiting a large hyperpolarizing shift in the voltage dependence of activation, accelerated activation, and delayed deactivation consistent with a relative stabilization of the open conformation, along with increased current density. Leveraging the cryogenic electron microscopy (cryo-EM) structure of Kv3.1, molecular dynamic simulations suggest that a strong π-π stacking interaction between the variant Tyr125 and Tyr156 in the α-6 helix of the T1 domain promotes a relative stabilization of the open conformation of the channel, which underlies the observed gain of function. A multicompartment computational model of a Kv3-expressing parvalbumin-positive cerebral cortex fast-spiking γ-aminobutyric acidergic (GABAergic) interneuron (PV-IN) demonstrates how the Kv3.2-Cys125Tyr variant impairs neuronal excitability and dysregulates inhibition in cerebral cortex circuits to explain the resulting epilepsy.
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Affiliation(s)
- Jerome Clatot
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
- The Epilepsy Neurogenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia,PA19104
| | | | - Qiansheng Liang
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA19107
| | - Tanadet Pipatpolkai
- Department of Applied Physics, Science for Life Laboratory, Royal Institute of Technology, SolnaSE-171 21, Sweden
| | - Shavonne L. Massey
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
- The Epilepsy Neurogenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia,PA19104
- The Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA19104
| | - Ingo Helbig
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
- The Epilepsy Neurogenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia,PA19104
- The Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA19104
- Department of Biomedical and Health Informatics, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
| | - Lucie Delemotte
- Department of Applied Physics, Science for Life Laboratory, Royal Institute of Technology, SolnaSE-171 21, Sweden
| | - Tim P. Vogels
- The Institute of Science and Technology Austria, Klosterneuburg3400, Austria
| | - Manuel Covarrubias
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA19107
| | - Ethan M. Goldberg
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
- The Epilepsy Neurogenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia,PA19104
- The Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA19104
- The Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA19104
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Fan HC, Yang MT, Lin LC, Chiang KL, Chen CM. Clinical and Genetic Features of Dravet Syndrome: A Prime Example of the Role of Precision Medicine in Genetic Epilepsy. Int J Mol Sci 2023; 25:31. [PMID: 38203200 PMCID: PMC10779156 DOI: 10.3390/ijms25010031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 12/14/2023] [Accepted: 12/17/2023] [Indexed: 01/12/2024] Open
Abstract
Dravet syndrome (DS), also known as severe myoclonic epilepsy of infancy, is a rare and drug-resistant form of developmental and epileptic encephalopathies, which is both debilitating and challenging to manage, typically arising during the first year of life, with seizures often triggered by fever, infections, or vaccinations. It is characterized by frequent and prolonged seizures, developmental delays, and various other neurological and behavioral impairments. Most cases result from pathogenic mutations in the sodium voltage-gated channel alpha subunit 1 (SCN1A) gene, which encodes a critical voltage-gated sodium channel subunit involved in neuronal excitability. Precision medicine offers significant potential for improving DS diagnosis and treatment. Early genetic testing enables timely and accurate diagnosis. Advances in our understanding of DS's underlying genetic mechanisms and neurobiology have enabled the development of targeted therapies, such as gene therapy, offering more effective and less invasive treatment options for patients with DS. Targeted and gene therapies provide hope for more effective and personalized treatments. However, research into novel approaches remains in its early stages, and their clinical application remains to be seen. This review addresses the current understanding of clinical DS features, genetic involvement in DS development, and outcomes of novel DS therapies.
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Affiliation(s)
- Hueng-Chuen Fan
- Department of Pediatrics, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan;
- Department of Rehabilitation, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli 356, Taiwan
- Department of Life Sciences, Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
| | - Ming-Tao Yang
- Department of Pediatrics, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan;
- Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan
| | - Lung-Chang Lin
- Department of Pediatrics, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan;
- Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Kuo-Liang Chiang
- Department of Pediatric Neurology, Kuang-Tien General Hospital, Taichung 433, Taiwan;
- Department of Nutrition, Hungkuang University, Taichung 433, Taiwan
| | - Chuan-Mu Chen
- Department of Life Sciences, Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
- The iEGG and Animal Biotechnology Center, and Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung 402, Taiwan
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9
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Zidar N, Tomašič T, Kikelj D, Durcik M, Tytgat J, Peigneur S, Rogers M, Haworth A, Kirby RW. New aryl and acylsulfonamides as state-dependent inhibitors of Na v1.3 voltage-gated sodium channel. Eur J Med Chem 2023; 258:115530. [PMID: 37329714 DOI: 10.1016/j.ejmech.2023.115530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 06/19/2023]
Abstract
Voltage-gated sodium channels (Navs) play an essential role in neurotransmission, and their dysfunction is often a cause of various neurological disorders. The Nav1.3 isoform is found in the CNS and upregulated after injury in the periphery, but its role in human physiology has not yet been fully elucidated. Reports suggest that selective Nav1.3 inhibitors could be used as novel therapeutics to treat pain or neurodevelopmental disorders. Few selective inhibitors of this channel are known in the literature. In this work, we report the discovery of a new series of aryl and acylsulfonamides as state-dependent inhibitors of Nav1.3 channels. Using a ligand-based 3D similarity search and subsequent hit optimization, we identified and prepared a series of 47 novel compounds and tested them on Nav1.3, Nav1.5, and a selected subset also on Nav1.7 channels in a QPatch patch-clamp electrophysiology assay. Eight compounds had an IC50 value of less than 1 μM against the Nav1.3 channel inactivated state, with one compound displaying an IC50 value of 20 nM, whereas activity against the inactivated state of the Nav1.5 channel and Nav1.7 channel was approximately 20-fold weaker. None of the compounds showed use-dependent inhibition of the cardiac isoform Nav1.5 at a concentration of 30 μM. Further selectivity testing of the most promising hits was measured using the two-electrode voltage-clamp method against the closed state of the Nav1.1-Nav1.8 channels, and compound 15b displayed small, yet selective, effects against the Nav1.3 channel, with no activity against the other isoforms. Additional selectivity testing of promising hits against the inactivated state of the Nav1.3, Nav1.7, and Nav1.8 channels revealed several compounds with robust and selective activity against the inactivated state of the Nav1.3 channel among the three isoforms tested. Moreover, the compounds were not cytotoxic at a concentration of 50 μM, as demonstrated by the assay in human HepG2 cells (hepatocellular carcinoma cells). The novel state-dependent inhibitors of Nav1.3 discovered in this work provide a valuable tool to better evaluate this channel as a potential drug target.
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Affiliation(s)
- Nace Zidar
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, 1000, Ljubljana, Slovenia.
| | - Tihomir Tomašič
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, 1000, Ljubljana, Slovenia
| | - Danijel Kikelj
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, 1000, Ljubljana, Slovenia
| | - Martina Durcik
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, 1000, Ljubljana, Slovenia
| | - Jan Tytgat
- University of Leuven (KU Leuven), Toxicology & Pharmacology, O&N2, PO Box 922, Herestraat 49, 3000, Leuven, Belgium
| | - Steve Peigneur
- University of Leuven (KU Leuven), Toxicology & Pharmacology, O&N2, PO Box 922, Herestraat 49, 3000, Leuven, Belgium
| | - Marc Rogers
- Metrion Biosciences Limited, Building 2, Granta Centre, Granta Park, Great Abington, Cambridge, CB21 6AL, UK
| | - Alexander Haworth
- Metrion Biosciences Limited, Building 2, Granta Centre, Granta Park, Great Abington, Cambridge, CB21 6AL, UK
| | - Robert W Kirby
- Metrion Biosciences Limited, Building 2, Granta Centre, Granta Park, Great Abington, Cambridge, CB21 6AL, UK
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10
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Tahara M, Higurashi N, Hata J, Nishikawa M, Ito K, Hirose S, Kaneko T, Mashimo T, Sakuma T, Yamamoto T, Okano HJ. Developmental changes in brain activity of heterozygous Scn1a knockout rats. Front Neurol 2023; 14:1125089. [PMID: 36998780 PMCID: PMC10043303 DOI: 10.3389/fneur.2023.1125089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/20/2023] [Indexed: 03/17/2023] Open
Abstract
IntroductionDravet syndrome (DS) is an infantile-onset developmental and epileptic encephalopathy characterized by an age-dependent evolution of drug-resistant seizures and poor developmental outcomes. Functional impairment of gamma-aminobutyric acid (GABA)ergic interneurons due to loss-of-function mutation of SCN1A is currently considered the main pathogenesis. In this study, to better understand the age-dependent changes in the pathogenesis of DS, we characterized the activity of different brain regions in Scn1a knockout rats at each developmental stage.MethodsWe established an Scn1a knockout rat model and examined brain activity from postnatal day (P) 15 to 38 using a manganese-enhanced magnetic resonance imaging technique (MEMRI).ResultsScn1a heterozygous knockout (Scn1a+/−) rats showed a reduced expression of voltage-gated sodium channel alpha subunit 1 protein in the brain and heat-induced seizures. Neural activity was significantly higher in widespread brain regions of Scn1a+/− rats than in wild-type rats from P19 to P22, but this difference did not persist thereafter. Bumetanide, a Na+-K+-2Cl− cotransporter 1 inhibitor, mitigated hyperactivity to the wild-type level, although no change was observed in the fourth postnatal week. Bumetanide also increased heat-induced seizure thresholds of Scn1a+/− rats at P21.ConclusionsIn Scn1a+/− rats, neural activity in widespread brain regions increased during the third postnatal week, corresponding to approximately 6 months of age in humans, when seizures most commonly develop in DS. In addition to impairment of GABAergic interneurons, the effects of bumetanide suggest a possible contribution of immature type A gamma-aminobutyric acid receptor signaling to transient hyperactivity and seizure susceptibility during the early stage of DS. This hypothesis should be addressed in the future. MEMRI is a potential technique for visualizing changes in basal brain activity in developmental and epileptic encephalopathies.
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Affiliation(s)
- Mayu Tahara
- Department of Pediatrics, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- Division of Regenerative Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Norimichi Higurashi
- Department of Pediatrics, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- *Correspondence: Norimichi Higurashi
| | - Junichi Hata
- Division of Regenerative Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Arakawa-ku, Tokyo, Japan
| | - Masako Nishikawa
- Clinical Research Support Center, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Ken Ito
- Department of Pediatrics, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- Division of Regenerative Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Shinichi Hirose
- General Medical Research Center, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Takehito Kaneko
- Division of Fundamental and Applied Sciences, Graduate School of Science and Engineering, Iwate University, Morioka, Japan
| | - Tomoji Mashimo
- Division of Animal Genetics, Laboratory Animal Research Center, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo, Japan
| | - Tetsushi Sakuma
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Takashi Yamamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Hirotaka James Okano
- Division of Regenerative Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- Hirotaka James Okano
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11
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Structure and Function of Sodium Channel Nav1.3 in Neurological Disorders. Cell Mol Neurobiol 2023; 43:575-584. [PMID: 35332400 DOI: 10.1007/s10571-022-01211-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 03/07/2022] [Indexed: 11/03/2022]
Abstract
Nav1.3, encoded by the SCN3A gene, is a voltage-gated sodium channel on the cell membrane. It is expressed abundantly in the fetal brain but little in the normal adult brain. It is involved in the generation and conduction of action potentials in excitable cells. Nav1.3 plays an important role in many neurological diseases. The aim of this review is to summarize new findings about Nav1.3 in the field of neurology. Many mutations of SCN3A can lead to neuronal hyperexcitability and then cause epilepsy. The rapid recovery from inactivation and slow closed-state inactivation kinetics of Nav1.3 leads to a reduced activation threshold of the channel and a high frequency of firing of neurons. Hyperactivity of Nav1.3 also induces increased excitability of sensory neurons, a lower nociceptive threshold, and neuropathic pain. This review summarizes the structure and the function of Nav1.3 and focuses on its relationship with epilepsy and neuropathic pain.
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12
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A nutraceutical product, extracted from Cannabis sativa, modulates voltage-gated sodium channel function. J Cannabis Res 2022; 4:30. [PMID: 35689251 PMCID: PMC9185959 DOI: 10.1186/s42238-022-00136-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 05/08/2022] [Indexed: 11/24/2022] Open
Abstract
Background Purified cannabidiol (CBD), a non-psychoactive phytocannabinoid, has gained regulatory approval to treat intractable childhood epilepsies. Despite this, artisanal and commercial CBD-dominant hemp-based products continue to be used by epilepsy patients. Notably, the CBD doses used in these latter products are much lower than that found to be effective in reducing seizures in clinical trials with purified CBD. This might be because these CBD-dominant hemp products contain other bioactive compounds, including phytocannabinoids and terpenes, which may exert unique effects on epilepsy-relevant drug targets. Voltage-gated sodium (NaV) channels are vital for initiation of neuronal action potential propagation and genetic mutations in these channels result in epilepsy phenotypes. Recent studies suggest that NaV channels are inhibited by purified CBD. However, the effect of cannabis-based products on the function of NaV channels is unknown. Methods Using automated-planar patch-clamp technology, we profile a hemp-derived nutraceutical product (NP) against human NaV1.1–NaV1.8 expressed in mammalian cells to examine effects on the biophysical properties of channel conductance, steady-state fast inactivation and recovery from fast inactivation. Results NP modifies peak current amplitude of the NaV1.1–NaV1.7 subtypes and has variable effects on the biophysical properties for all channel subtypes tested. NP potently inhibits NaV channels revealing half-maximal inhibitory concentration (IC50) values of between 1.6 and 4.2 μg NP/mL. Purified CBD inhibits NaV1.1, NaV1.2, NaV1.6 and NaV1.7 to reveal IC50 values in the micromolar range. The CBD content of the product equates to IC50 values (93–245 nM), which are at least an order of magnitude lower than purified CBD. Unlike NP, hemp seed oil vehicle alone did not inhibit NaV channels, suggesting that the inhibitory effects of NP are independent of hemp seed oil. Conclusions This CBD-dominant NP potently inhibits NaV channels. Future study of the individual elements of NP, including phytocannabinoids and terpenes, may reveal a potent individual component or that its components interact to modulate NaV channels. Supplementary Information The online version contains supplementary material available at 10.1186/s42238-022-00136-x.
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13
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Sodium channel expression and transcript variation in the developing brain of human, Rhesus monkey, and mouse. Neurobiol Dis 2022; 164:105622. [PMID: 35031483 DOI: 10.1016/j.nbd.2022.105622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 12/16/2022] Open
Abstract
Genetic variation in voltage-gated sodium (NaV) channels is a significant contributor to neurodevelopmental disorders. NaV channel alpha subunits are encoded by the SCNxA family and four are predominately expressed in the brain: SCN1A, SCN2A, SCN3A, and SCN8A. Gene expression is developmentally regulated, and they are known to express functionally distinct transcript variants. Precision therapies targeting these genes and their transcript variants are currently in preclinical development, yet the developmental expression of these transcripts in the human brain is yet to be fully understood. Additionally, the functional consequences of some mutations differ depending on the studied channel isoform, suggesting differential transcript variant expression can affect disease prognoses. We characterise the expression of the four SCNxAs and their transcript variants in human, Rhesus monkey and mouse brain using publicly available RNA-sequencing data and analysis tools, demonstrating that this approach can be used to answer important biological questions of gene and transcript developmental regulation. We find that gene expression and transcript variant regulation are conserved across species at similar developmental stages and determine the developmental milestones for transcript variant expression. Our study provides a guide to researchers testing therapies and clinicians advising prognoses based on the expression of channel isoforms.
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14
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Layer N, Sonnenberg L, Pardo González E, Benda J, Hedrich UBS, Lerche H, Koch H, Wuttke TV. Dravet Variant SCN1A A1783V Impairs Interneuron Firing Predominantly by Altered Channel Activation. Front Cell Neurosci 2021; 15:754530. [PMID: 34776868 PMCID: PMC8581729 DOI: 10.3389/fncel.2021.754530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/28/2021] [Indexed: 11/23/2022] Open
Abstract
Dravet syndrome (DS) is a developmental epileptic encephalopathy mainly caused by functional NaV1.1 haploinsufficiency in inhibitory interneurons. Recently, a new conditional mouse model expressing the recurrent human p.(Ala1783Val) missense variant has become available. In this study, we provided an electrophysiological characterization of this variant in tsA201 cells, revealing both altered voltage-dependence of activation and slow inactivation without reduced sodium peak current density. Based on these data, simulated interneuron (IN) firing properties in a conductance-based single-compartment model suggested surprisingly similar firing deficits for NaV1.1A1783V and full haploinsufficiency as caused by heterozygous truncation variants. Impaired NaV1.1A1783V channel activation was predicted to have a significantly larger impact on channel function than altered slow inactivation and is therefore proposed as the main mechanism underlying IN dysfunction. The computational model was validated in cortical organotypic slice cultures derived from conditional Scn1aA1783V mice. Pan-neuronal activation of the p.Ala1783V in vitro confirmed a predicted IN firing deficit and revealed an accompanying reduction of interneuronal input resistance while demonstrating normal excitability of pyramidal neurons. Altered input resistance was fed back into the model for further refinement. Taken together these data demonstrate that primary loss of function (LOF) gating properties accompanied by altered membrane characteristics may match effects of full haploinsufficiency on the neuronal level despite maintaining physiological peak current density, thereby causing DS.
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Affiliation(s)
- Nikolas Layer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lukas Sonnenberg
- Institute for Neurobiology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Emilio Pardo González
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Jan Benda
- Institute for Neurobiology, Eberhard Karls University Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, Eberhard Karls Universitat, Tübingen, Germany
| | - Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Henner Koch
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Epileptology, Neurology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany
| | - Thomas V Wuttke
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Neurosurgery, University of Tübingen, Tübingen, Germany
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15
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Inherited Developmental and Epileptic Encephalopathies. Neurol Int 2021; 13:555-568. [PMID: 34842787 PMCID: PMC8628919 DOI: 10.3390/neurolint13040055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 01/13/2023] Open
Abstract
Epileptic encephalopathies often have a genetic etiology. The epileptic activity itself exerts a direct detrimental effect on neurodevelopment, which may add to the cognitive impairment induced by the underlying mutation (“developmental and epileptic encephalopathy”). The focus of this review is on inherited syndromes. The phenotypes of genetic disorders affecting ion channels, metabolic signalling, membrane trafficking and exocytosis, cell adhesion, cell growth and proliferation are discussed. Red flags suggesting family of genes or even specific genes are highlighted. The knowledge of the phenotypical spectrum can indeed prompt the clinician to suspect specific etiologies, expediting the diagnosis.
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16
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Auffenberg E, Hedrich UB, Barbieri R, Miely D, Groschup B, Wuttke TV, Vogel N, Lührs P, Zanardi I, Bertelli S, Spielmann N, Gailus-Durner V, Fuchs H, Hrabě de Angelis M, Pusch M, Dichgans M, Lerche H, Gavazzo P, Plesnila N, Freilinger T. Hyperexcitable interneurons trigger cortical spreading depression in an Scn1a migraine model. J Clin Invest 2021; 131:142202. [PMID: 34546973 PMCID: PMC8553559 DOI: 10.1172/jci142202] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/02/2021] [Indexed: 12/12/2022] Open
Abstract
Cortical spreading depression (CSD), a wave of depolarization followed by depression of cortical activity, is a pathophysiological process implicated in migraine with aura and various other brain pathologies, such as ischemic stroke and traumatic brain injury. To gain insight into the pathophysiology of CSD, we generated a mouse model for a severe monogenic subtype of migraine with aura, familial hemiplegic migraine type 3 (FHM3). FHM3 is caused by mutations in SCN1A, encoding the voltage-gated Na+ channel NaV1.1 predominantly expressed in inhibitory interneurons. Homozygous Scn1aL1649Q knock-in mice died prematurely, whereas heterozygous mice had a normal lifespan. Heterozygous Scn1aL1649Q knock-in mice compared with WT mice displayed a significantly enhanced susceptibility to CSD. We found L1649Q to cause a gain-of-function effect with an impaired Na+-channel inactivation and increased ramp Na+ currents leading to hyperactivity of fast-spiking inhibitory interneurons. Brain slice recordings using K+-sensitive electrodes revealed an increase in extracellular K+ in the early phase of CSD in heterozygous mice, likely representing the mechanistic link between interneuron hyperactivity and CSD initiation. The neuronal phenotype and premature death of homozygous Scn1aL1649Q knock-in mice was partially rescued by GS967, a blocker of persistent Na+ currents. Collectively, our findings identify interneuron hyperactivity as a mechanism to trigger CSD.
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Affiliation(s)
- Eva Auffenberg
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany
| | - Ulrike Bs Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Raffaella Barbieri
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Daniela Miely
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Bernhard Groschup
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany
| | - Thomas V Wuttke
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Niklas Vogel
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Philipp Lührs
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ilaria Zanardi
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Sara Bertelli
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Nadine Spielmann
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Valerie Gailus-Durner
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Helmut Fuchs
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Martin Hrabě de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.,Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, Freising, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Michael Pusch
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Martin Dichgans
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Paola Gavazzo
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Tobias Freilinger
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Neurology, Klinikum Passau, Passau, Germany
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Huang CH, Hung PL, Fan PC, Lin KL, Hsu TR, Chou IJ, Ho CS, Chou IC, Lin WS, Lee IC, Fan HC, Chen SJ, Liang JS, Tu YF, Chang TM, Hu SC, Wong LC, Hung KL, Lee WT. Clinical spectrum and the comorbidities of Dravet syndrome in Taiwan and the possible molecular mechanisms. Sci Rep 2021; 11:20242. [PMID: 34642351 PMCID: PMC8511137 DOI: 10.1038/s41598-021-98517-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 09/03/2021] [Indexed: 11/09/2022] Open
Abstract
Dravet syndrome (DS) is an uncommon epilepsy syndrome that may negatively affect the patients and their caregivers. However, reliable and valid measures of its impact on caregivers and the characteristics of patients with DS in Taiwan are lacking. This study aimed to describe the characteristics of patients with DS and concerns of their caregivers and establish a baseline frequency of disease characteristics using a cross-sectional survey in Taiwan. We assessed the caregivers of patients with DS using an online anonymous questionnaire. The seizure frequency decreased with age, although lacking statistical significance. Vaccines show no influence on the condition of patients with DS. Our findings revealed the highest impact on the domains affecting the caregivers’ daily life, including additional household tasks, symptom observation, further medical plan, and financial issues. Caregivers also expressed concerns regarding the lack of independence/constant care, seizure control, speech/communication, and impacts on siblings because of long-term care of the patients in parents’ absence. Our findings highlight the significant effects of caring for a child with DS on the lives of their caregivers in Taiwan; these findings will help raise awareness regarding the needs of these families. Furthermore, we discussed the possible pathophysiological mechanisms of associated comorbidities.
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Affiliation(s)
- Chia-Hsuan Huang
- Division of Pediatric Neurology, Department of Pediatrics, National Taiwan University Hospital Yunlin Branch, Yunlin County, Taiwan
| | - Pi-Lien Hung
- Department of Pediatric Neurology, Chang Gung Memorial Hospital-Kaohsiung, Kaohsiung, Taiwan
| | - Pi-Chuan Fan
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Kuang-Lin Lin
- Division of Pediatric Neurology, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Ting-Rong Hsu
- Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - I-Jun Chou
- Division of Pediatric Neurology, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Che-Sheng Ho
- Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan
| | - I-Ching Chou
- Division of Pediatrics Neurology, China Medical University Children's Hospital, Taichung, Taiwan
| | - Wei-Sheng Lin
- Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Inn-Chi Lee
- Institute of Medicine, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Hueng-Chuen Fan
- Department of Pediatrics, Tungs' Taichung Metroharbor Hospital, Taichung, Taiwan
| | - Shyi-Jou Chen
- Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Jao-Shwann Liang
- Department of Pediatrics, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Yi-Fang Tu
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Tung-Ming Chang
- Department of Pediatric Neurology, Changhua Christian Children's Hospital, Changhua, Taiwan
| | - Su-Ching Hu
- Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan
| | - Lee-Chin Wong
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan
| | - Kun-Long Hung
- Department of Pediatrics, Fu-Jen Catholic University Hospital, Fu-Jen Catholic University, New Taipei City, Taiwan
| | - Wang-Tso Lee
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan. .,Department of Pediatric Neurology, National Taiwan University Children's Hospital, 8, Chung-Shan South Road, Taipei, 100, Taiwan.
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18
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Boscia F, Elkjaer ML, Illes Z, Kukley M. Altered Expression of Ion Channels in White Matter Lesions of Progressive Multiple Sclerosis: What Do We Know About Their Function? Front Cell Neurosci 2021; 15:685703. [PMID: 34276310 PMCID: PMC8282214 DOI: 10.3389/fncel.2021.685703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/23/2021] [Indexed: 12/19/2022] Open
Abstract
Despite significant advances in our understanding of the pathophysiology of multiple sclerosis (MS), knowledge about contribution of individual ion channels to axonal impairment and remyelination failure in progressive MS remains incomplete. Ion channel families play a fundamental role in maintaining white matter (WM) integrity and in regulating WM activities in axons, interstitial neurons, glia, and vascular cells. Recently, transcriptomic studies have considerably increased insight into the gene expression changes that occur in diverse WM lesions and the gene expression fingerprint of specific WM cells associated with secondary progressive MS. Here, we review the ion channel genes encoding K+, Ca2+, Na+, and Cl- channels; ryanodine receptors; TRP channels; and others that are significantly and uniquely dysregulated in active, chronic active, inactive, remyelinating WM lesions, and normal-appearing WM of secondary progressive MS brain, based on recently published bulk and single-nuclei RNA-sequencing datasets. We discuss the current state of knowledge about the corresponding ion channels and their implication in the MS brain or in experimental models of MS. This comprehensive review suggests that the intense upregulation of voltage-gated Na+ channel genes in WM lesions with ongoing tissue damage may reflect the imbalance of Na+ homeostasis that is observed in progressive MS brain, while the upregulation of a large number of voltage-gated K+ channel genes may be linked to a protective response to limit neuronal excitability. In addition, the altered chloride homeostasis, revealed by the significant downregulation of voltage-gated Cl- channels in MS lesions, may contribute to an altered inhibitory neurotransmission and increased excitability.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", Naples, Italy
| | - Maria Louise Elkjaer
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Maria Kukley
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
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Abstract
Pathogenic variants in epilepsy genes result in a spectrum of clinical severity. One source of phenotypic heterogeneity is modifier genes that affect expressivity of a primary pathogenic variant. Mouse epilepsy models also display varying degrees of clinical severity on different genetic backgrounds. Mice with heterozygous deletion of Scn1a (Scn1a+/−) model Dravet syndrome, a severe epilepsy most often caused by SCN1A haploinsufficiency. Scn1a+/− mice recapitulate features of Dravet syndrome, including spontaneous seizures, sudden death, and cognitive/behavioral deficits. Scn1a+/− mice maintained on the 129S6/SvEvTac (129) strain have normal lifespan and no spontaneous seizures. In contrast, admixture with C57BL/6J (B6) results in epilepsy and premature lethality. We previously mapped Dravet Survival Modifier loci (Dsm1-Dsm5) responsible for strain-dependent differences in survival. Gabra2, encoding the GABAA α2 subunit, was nominated as a candidate modifier at Dsm1. Direct measurement of GABAA receptors found lower abundance of α2-containing receptors in hippocampal synapses of B6 mice relative to 129. We also identified a B6-specific single nucleotide deletion within Gabra2 that lowers mRNA and protein by nearly 50%. Repair of this deletion reestablished normal levels of Gabra2 expression. In this study, we used B6 mice with a repaired Gabra2 allele to evaluate Gabra2 as a genetic modifier of severity in Scn1a+/− mice. Gabra2 repair restored transcript and protein expression, increased abundance of α2-containing GABAA receptors in hippocampal synapses, and rescued epilepsy phenotypes of Scn1a+/− mice. These findings validate Gabra2 as a genetic modifier of Dravet syndrome, and support enhancing function of α2-containing GABAA receptors as treatment strategy for Dravet syndrome.
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20
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Li W, Zhao W, Wang J, Zhang X, Qian X, Gu R, He G. Identification of a novel variant p.Ser606Gly in SCN3A associated with childhood absence epilepsy. Epilepsy Res 2021; 175:106682. [PMID: 34102392 DOI: 10.1016/j.eplepsyres.2021.106682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/14/2021] [Accepted: 05/31/2021] [Indexed: 10/21/2022]
Abstract
Sodium (Na+) channels are the basis for action potential generation and propagation, which play a key role in the regulation of neuronal excitability. SCN3A is a gene encoding for sodium channel protein type 3 subunit alpha (or known as Nav1.3). This study aimed to explore SCN3A genetic variants in a cohort of childhood absence epilepsy (CAE) via whole exome sequencing. A novel SCN3A missense variant (c.A1816G, p.Ser606Gly) was identified in a patient with CAE. This variant had not been reported in both 1000G and ExAC databases. Bioinformatics analysis revealed that this variant was pathogenic and could transform the protein structure of Nav1.3. The reported phenotypes of SCN3A-related central nerve system disorders included multiple seizure types, polymicrogyria and different degrees of developmental delay/intellectual disability. The patient with p.Ser606Gly variant exhibited typical absence seizures. The MRI and CT scan results were normal, and EEG showed that 3-Hz spike-slow wave discharges. In conclusion, our findings not only broaden the pathogenic spectrum of SCN3A, but also extend the clinical phenotypes of SCN3A-related CAE.
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Affiliation(s)
- Wei Li
- School of Forensic Medicine, Xinxiang Medical University, Xinxiang, China
| | - Wenli Zhao
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
| | - Jing Wang
- School of Forensic Medicine, Xinxiang Medical University, Xinxiang, China
| | - Xiaoli Zhang
- Department of Neurology, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Xinlai Qian
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China.
| | - Renjun Gu
- Department of Neurology, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China.
| | - Guoyang He
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China.
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21
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Haigh JL, Adhikari A, Copping NA, Stradleigh T, Wade AA, Catta-Preta R, Su-Feher L, Zdilar I, Morse S, Fenton TA, Nguyen A, Quintero D, Agezew S, Sramek M, Kreun EJ, Carter J, Gompers A, Lambert JT, Canales CP, Pennacchio LA, Visel A, Dickel DE, Silverman JL, Nord AS. Deletion of a non-canonical regulatory sequence causes loss of Scn1a expression and epileptic phenotypes in mice. Genome Med 2021; 13:69. [PMID: 33910599 PMCID: PMC8080386 DOI: 10.1186/s13073-021-00884-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/06/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Genes with multiple co-active promoters appear common in brain, yet little is known about functional requirements for these potentially redundant genomic regulatory elements. SCN1A, which encodes the NaV1.1 sodium channel alpha subunit, is one such gene with two co-active promoters. Mutations in SCN1A are associated with epilepsy, including Dravet syndrome (DS). The majority of DS patients harbor coding mutations causing SCN1A haploinsufficiency; however, putative causal non-coding promoter mutations have been identified. METHODS To determine the functional role of one of these potentially redundant Scn1a promoters, we focused on the non-coding Scn1a 1b regulatory region, previously described as a non-canonical alternative transcriptional start site. We generated a transgenic mouse line with deletion of the extended evolutionarily conserved 1b non-coding interval and characterized changes in gene and protein expression, and assessed seizure activity and alterations in behavior. RESULTS Mice harboring a deletion of the 1b non-coding interval exhibited surprisingly severe reductions of Scn1a and NaV1.1 expression throughout the brain. This was accompanied by electroencephalographic and thermal-evoked seizures, and behavioral deficits. CONCLUSIONS This work contributes to functional dissection of the regulatory wiring of a major epilepsy risk gene, SCN1A. We identified the 1b region as a critical disease-relevant regulatory element and provide evidence that non-canonical and seemingly redundant promoters can have essential function.
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Affiliation(s)
- Jessica L Haigh
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Anna Adhikari
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- MIND Institute and Department of Psychiatry and Behavioral Sciences, UC Davis School of Medicine, Sacramento, CA, USA
| | - Nycole A Copping
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- MIND Institute and Department of Psychiatry and Behavioral Sciences, UC Davis School of Medicine, Sacramento, CA, USA
| | - Tyler Stradleigh
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - A Ayanna Wade
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Rinaldo Catta-Preta
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Linda Su-Feher
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Iva Zdilar
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Sarah Morse
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Timothy A Fenton
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- MIND Institute and Department of Psychiatry and Behavioral Sciences, UC Davis School of Medicine, Sacramento, CA, USA
| | - Anh Nguyen
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Diana Quintero
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Samrawit Agezew
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Michael Sramek
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Ellie J Kreun
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Jasmine Carter
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Andrea Gompers
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Jason T Lambert
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Cesar P Canales
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Len A Pennacchio
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
- Comparative Biochemistry Program, University of California, Berkeley, Berkeley, CA, USA
| | - Axel Visel
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
- Comparative Biochemistry Program, University of California, Berkeley, Berkeley, CA, USA
- School of Natural Sciences, University of California, Merced, CA, USA
| | - Diane E Dickel
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
- Comparative Biochemistry Program, University of California, Berkeley, Berkeley, CA, USA
| | - Jill L Silverman
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA.
- MIND Institute and Department of Psychiatry and Behavioral Sciences, UC Davis School of Medicine, Sacramento, CA, USA.
| | - Alex S Nord
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA.
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA.
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22
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Mantegazza M, Cestèle S, Catterall WA. Sodium channelopathies of skeletal muscle and brain. Physiol Rev 2021; 101:1633-1689. [PMID: 33769100 DOI: 10.1152/physrev.00025.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium channels initiate action potentials in nerve, skeletal muscle, and other electrically excitable cells. Mutations in them cause a wide range of diseases. These channelopathy mutations affect every aspect of sodium channel function, including voltage sensing, voltage-dependent activation, ion conductance, fast and slow inactivation, and both biosynthesis and assembly. Mutations that cause different forms of periodic paralysis in skeletal muscle were discovered first and have provided a template for understanding structure, function, and pathophysiology at the molecular level. More recent work has revealed multiple sodium channelopathies in the brain. Here we review the well-characterized genetics and pathophysiology of the periodic paralyses of skeletal muscle and then use this information as a foundation for advancing our understanding of mutations in the structurally homologous α-subunits of brain sodium channels that cause epilepsy, migraine, autism, and related comorbidities. We include studies based on molecular and structural biology, cell biology and physiology, pharmacology, and mouse genetics. Our review reveals unexpected connections among these different types of sodium channelopathies.
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Affiliation(s)
- Massimo Mantegazza
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France
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23
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Voskobiynyk Y, Battu G, Felker SA, Cochran JN, Newton MP, Lambert LJ, Kesterson RA, Myers RM, Cooper GM, Roberson ED, Barsh GS. Aberrant regulation of a poison exon caused by a non-coding variant in a mouse model of Scn1a-associated epileptic encephalopathy. PLoS Genet 2021; 17:e1009195. [PMID: 33411788 PMCID: PMC7790302 DOI: 10.1371/journal.pgen.1009195] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/14/2020] [Indexed: 12/20/2022] Open
Abstract
Dravet syndrome (DS) is a developmental and epileptic encephalopathy that results from mutations in the Nav1.1 sodium channel encoded by SCN1A. Most known DS-causing mutations are in coding regions of SCN1A, but we recently identified several disease-associated SCN1A mutations in intron 20 that are within or near to a cryptic and evolutionarily conserved "poison" exon, 20N, whose inclusion is predicted to lead to transcript degradation. However, it is not clear how these intron 20 variants alter SCN1A expression or DS pathophysiology in an organismal context, nor is it clear how exon 20N is regulated in a tissue-specific and developmental context. We address those questions here by generating an animal model of our index case, NM_006920.4(SCN1A):c.3969+2451G>C, using gene editing to create the orthologous mutation in laboratory mice. Scn1a heterozygous knock-in (+/KI) mice exhibited an ~50% reduction in brain Scn1a mRNA and Nav1.1 protein levels, together with characteristics observed in other DS mouse models, including premature mortality, seizures, and hyperactivity. In brain tissue from adult Scn1a +/+ animals, quantitative RT-PCR assays indicated that ~1% of Scn1a mRNA included exon 20N, while brain tissue from Scn1a +/KI mice exhibited an ~5-fold increase in the extent of exon 20N inclusion. We investigated the extent of exon 20N inclusion in brain during normal fetal development in RNA-seq data and discovered that levels of inclusion were ~70% at E14.5, declining progressively to ~10% postnatally. A similar pattern exists for the homologous sodium channel Nav1.6, encoded by Scn8a. For both genes, there is an inverse relationship between the level of functional transcript and the extent of poison exon inclusion. Taken together, our findings suggest that poison exon usage by Scn1a and Scn8a is a strategy to regulate channel expression during normal brain development, and that mutations recapitulating a fetal-like pattern of splicing cause reduced channel expression and epileptic encephalopathy.
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Affiliation(s)
- Yuliya Voskobiynyk
- Center for Neurodegeneration and Experimental Therapeutics, Alzheimer’s Disease Center, and Evelyn F. McKnight Brain Institute, Departments, of Neurology and Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Gopal Battu
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, United States of America
| | - Stephanie A. Felker
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, United States of America
- Department of Department of Biotechnology Science and Engineering, University of Alabama in Huntsville, Hunstville, AL, United States AL, United States of America
| | - J. Nicholas Cochran
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, United States of America
| | - Megan P. Newton
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Laura J. Lambert
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Robert A. Kesterson
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Richard M. Myers
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, United States of America
| | - Gregory M. Cooper
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, United States of America
| | - Erik D. Roberson
- Center for Neurodegeneration and Experimental Therapeutics, Alzheimer’s Disease Center, and Evelyn F. McKnight Brain Institute, Departments, of Neurology and Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States of America
- * E-mail: (GSB); (EDR)
| | - Gregory S. Barsh
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, United States of America
- * E-mail: (GSB); (EDR)
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24
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Mohamed SA, Aldeaf SA, Elhassan R, Hussein A, Gassoum A, Abdrabo AEA. Association of SCN1A Mutations with Epilepsy among Sudanese Patients. NEUROSCIENCE AND MEDICINE 2021; 12:90-102. [DOI: 10.4236/nm.2021.123008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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25
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A selective NaV1.1 activator with potential for treatment of Dravet syndrome epilepsy. Biochem Pharmacol 2020; 181:113991. [DOI: 10.1016/j.bcp.2020.113991] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/21/2020] [Indexed: 12/19/2022]
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26
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Menezes LFS, Sabiá Júnior EF, Tibery DV, Carneiro LDA, Schwartz EF. Epilepsy-Related Voltage-Gated Sodium Channelopathies: A Review. Front Pharmacol 2020; 11:1276. [PMID: 33013363 PMCID: PMC7461817 DOI: 10.3389/fphar.2020.01276] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/31/2020] [Indexed: 12/29/2022] Open
Abstract
Epilepsy is a disease characterized by abnormal brain activity and a predisposition to generate epileptic seizures, leading to neurobiological, cognitive, psychological, social, and economic impacts for the patient. There are several known causes for epilepsy; one of them is the malfunction of ion channels, resulting from mutations. Voltage-gated sodium channels (NaV) play an essential role in the generation and propagation of action potential, and malfunction caused by mutations can induce irregular neuronal activity. That said, several genetic variations in NaV channels have been described and associated with epilepsy. These mutations can affect channel kinetics, modifying channel activation, inactivation, recovery from inactivation, and/or the current window. Among the NaV subtypes related to epilepsy, NaV1.1 is doubtless the most relevant, with more than 1500 mutations described. Truncation and missense mutations are the most observed alterations. In addition, several studies have already related mutated NaV channels with the electrophysiological functioning of the channel, aiming to correlate with the epilepsy phenotype. The present review provides an overview of studies on epilepsy-associated mutated human NaV1.1, NaV1.2, NaV1.3, NaV1.6, and NaV1.7.
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Affiliation(s)
- Luis Felipe Santos Menezes
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Elias Ferreira Sabiá Júnior
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Diogo Vieira Tibery
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Lilian Dos Anjos Carneiro
- Faculdade de Medicina, Centro Universitário Euro Americano, Brasília, Brazil.,Faculdade de Medicina, Centro Universitário do Planalto Central, Brasília, Brazil
| | - Elisabeth Ferroni Schwartz
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
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27
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Martín-Suárez S, Abiega O, Ricobaraza A, Hernandez-Alcoceba R, Encinas JM. Alterations of the Hippocampal Neurogenic Niche in a Mouse Model of Dravet Syndrome. Front Cell Dev Biol 2020; 8:654. [PMID: 32793597 PMCID: PMC7385077 DOI: 10.3389/fcell.2020.00654] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/01/2020] [Indexed: 01/24/2023] Open
Abstract
Hippocampal neurogenesis, the process by which neural stem cells (NSCs) continuously generate new neurons in the dentate gyrus (DG) of most mammals including humans, is chiefly regulated by neuronal activity. Thus, severe alterations have been found in samples from epilepsy patients and in the hippocampal neurogenic niche in mouse models of epilepsy. Reactive-like and gliogenic NSCs plus aberrant newborn neurons with altered migration, morphology, and functional properties are induced by seizures in experimental models of temporal lobe epilepsy. Hippocampal neurogenesis participates in memory and learning and in the control of anxiety and stress. It has been therefore hypothesized that part of the cognitive symptoms associated with epilepsy could be promoted by impaired hippocampal neurogenesis. We here analyze for the first time the alterations of the neurogenic niche in a novel mouse model of Dravet syndrome (DS), a genetic encephalopathy with severe epilepsy in infancy and multiple neurological comorbidities. Scn1aWT/A1783V mice, hereafter referred to as DS, carrying a heterozygous and clinically relevant SCN1A mutation (A1783V) recapitulate the disease at the genetic and phenotypic levels. We demonstrate that in the neurogenic niche of young adult DS mice there are fewer NSCs, they have impaired cell division and bear reactive-like morphology. In addition, there is significant aberrant neurogenesis. Newborn immature neurons migrate abnormally, and several morphological features are drastically changed. Thus, this study shows for the first time important modifications in hippocampal neurogenesis in DS and opens venues for further research on this topic.
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Affiliation(s)
- Soraya Martín-Suárez
- The Neural Stem Cell and Neurogenesis Laboratory, Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Oihane Abiega
- The Neural Stem Cell and Neurogenesis Laboratory, Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Ana Ricobaraza
- Gene Therapy Program CIMA, IdiSNA, Navarra Institute for Health Research, University of Navarra, Pamplona, Spain
| | - Rubén Hernandez-Alcoceba
- Gene Therapy Program CIMA, IdiSNA, Navarra Institute for Health Research, University of Navarra, Pamplona, Spain
| | - Juan Manuel Encinas
- The Neural Stem Cell and Neurogenesis Laboratory, Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain.,IKERBASQUE, The Basque Foundation for Science, Bilbao, Spain
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28
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Zaman T, Helbig KL, Clatot J, Thompson CH, Kang SK, Stouffs K, Jansen AE, Verstraete L, Jacquinet A, Parrini E, Guerrini R, Fujiwara Y, Miyatake S, Ben‐Zeev B, Bassan H, Reish O, Marom D, Hauser N, Vu T, Ackermann S, Spencer CE, Lippa N, Srinivasan S, Charzewska A, Hoffman‐Zacharska D, Fitzpatrick D, Harrison V, Vasudevan P, Joss S, Pilz DT, Fawcett KA, Helbig I, Matsumoto N, Kearney JA, Fry AE, Goldberg EM. SCN3A
‐Related Neurodevelopmental Disorder: A Spectrum of Epilepsy and Brain Malformation. Ann Neurol 2020; 88:348-362. [DOI: 10.1002/ana.25809] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 05/05/2020] [Accepted: 05/25/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Tariq Zaman
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Katherine L. Helbig
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Jérôme Clatot
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Christopher H. Thompson
- Department of Pharmacology Northwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Seok Kyu Kang
- Department of Pharmacology Northwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Katrien Stouffs
- Center for Medical Genetics/Research Center for Reproduction and Genetics University Hospital Brussels, Free University of Brussels Brussels Belgium
| | - Anna E. Jansen
- Pediatric Neurology Unit, Department of Pediatrics University Hospital Brussels Brussels Belgium
- Neurogenetics Research Group Free University of Brussels Brussels Belgium
| | | | - Adeline Jacquinet
- Human Genetics Service Sart Tilman University Hospital Center Liege Belgium
| | - Elena Parrini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, Department of Neuroscience A. Meyer Children's Hospital, University of Florence Florence Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, Department of Neuroscience A. Meyer Children's Hospital, University of Florence Florence Italy
| | - Yuh Fujiwara
- Department of Pediatrics Yokohama City University Medical Center Yokohama Japan
| | - Satoko Miyatake
- Department of Human Genetics Yokohama City University Graduate School of Medicine Yokohama Japan
| | - Bruria Ben‐Zeev
- Pediatric Neurology Unit Edmond and Lili Safra Children's Hospital, Haim Sheba Medical Center Ramat Gan Israel
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Haim Bassan
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Pediatric Neurology & Development Center Shamir Medical Center (Assaf Harofe) Zerifin Israel
| | - Orit Reish
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Genetics Institute Shamir Medical Center (Assaf Harofe) Zerifin Zerifin Israel
| | - Daphna Marom
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Genetics Institute Shamir Medical Center (Assaf Harofe) Zerifin Zerifin Israel
| | - Natalie Hauser
- Inova Translational Medicine Institute Inova Health System Fairfax Virginia USA
| | - Thuy‐Anh Vu
- Department of Pediatric Neurology Children's National Medical Center, Washington, District of Columbia, and Pediatric Specialists of Virginia Fairfax Virginia USA
| | - Sally Ackermann
- Division of Paediatric Neurology, Department of Paediatrics and Child Health Red Cross War Memorial Children's Hospital, University of Cape Town Cape Town South Africa
| | - Careni E. Spencer
- Division of Human Genetics, Department of Medicine University of Cape Town, South Africa and Groote Schuur Hospital Cape Town South Africa
| | - Natalie Lippa
- Institute for Genomic Medicine Columbia University Medical Center New York New York USA
| | - Shraddha Srinivasan
- Department of Neurology Columbia University Medical Center New York New York USA
| | | | | | - David Fitzpatrick
- Medical Research Council Human Genetics Unit Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh Edinburgh United Kingdom
| | - Victoria Harrison
- Wessex Clinical Genetics Service Princess Anne Hospital Southampton United Kingdom
| | - Pradeep Vasudevan
- Department of Clinical Genetics University Hospitals Leicester National Health Service Trust Leicester United Kingdom
| | - Shelagh Joss
- West of Scotland Clinical Genetics Service Queen Elizabeth University Hospital Glasgow United Kingdom
| | - Daniela T. Pilz
- West of Scotland Clinical Genetics Service Queen Elizabeth University Hospital Glasgow United Kingdom
- Division of Cancer and Genetics School of Medicine, Cardiff University Cardiff United Kingdom
| | - Katherine A. Fawcett
- Medical Research Council (MRC) Computational Genomics Analysis and Training Programme, MRC Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital Oxford United Kingdom
| | - Ingo Helbig
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Department of Neurology, Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania USA
- Department of Biomedical and Health Informatics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Naomichi Matsumoto
- Department of Human Genetics Yokohama City University Graduate School of Medicine Yokohama Japan
| | - Jennifer A. Kearney
- Department of Pharmacology Northwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Andrew E. Fry
- Division of Cancer and Genetics School of Medicine, Cardiff University Cardiff United Kingdom
- Institute of Medical Genetics University Hospital of Wales Cardiff United Kingdom
| | - Ethan M. Goldberg
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Department of Neurology, Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania USA
- Department of Neuroscience Perelman School of Medicine, University of Pennsylvania Philadelphia Pennsylvania USA
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29
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Denomme N, Lukowski AL, Hull JM, Jameson MB, Bouza AA, Narayan ARH, Isom LL. The voltage-gated sodium channel inhibitor, 4,9-anhydrotetrodotoxin, blocks human Na v1.1 in addition to Na v1.6. Neurosci Lett 2020; 724:134853. [PMID: 32114117 PMCID: PMC7096269 DOI: 10.1016/j.neulet.2020.134853] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 02/12/2020] [Accepted: 02/18/2020] [Indexed: 11/23/2022]
Abstract
Voltage-gated sodium channels (VGSCs) are responsible for the initiation and propagation of action potentials in neurons. The human genome includes ten human VGSC α-subunit genes, SCN(X)A, encoding Nav1.1-1.9 plus Nax. To understand the unique role that each VGSC plays in normal and pathophysiological function in neural networks, compounds with high affinity and selectivity for specific VGSC subtypes are required. Toward that goal, a structural analog of the VGSC pore blocker tetrodotoxin, 4,9-anhydrotetrodotoxin (4,9-ah-TTX), has been reported to be more selective in blocking Na+ current mediated by Nav1.6 than other TTX-sensitive VGSCs, including Nav1.2, Nav1.3, Nav1.4, and Nav1.7. While SCN1A, encoding Nav1.1, has been implicated in several neurological diseases, the effects of 4,9-ah-TTX on Nav1.1-mediated Na+ current have not been tested. Here, we compared the binding of 4,9-ah-TTX for human and mouse brain preparations, and the effects of 4,9-ah-TTX on human Nav1.1-, Nav1.3- and Nav1.6-mediated Na+ currents using the whole-cell patch clamp technique in heterologous cells. We show that, while 4,9-ah-TTX administration results in significant blockade of Nav1.6-mediated Na+ current in the nanomolar range, it also has significant effects on Nav1.1-mediated Na+ current. Thus, 4,9-ah-TTX is not a useful tool in identifying Nav1.6-specific effects in human brain networks.
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Affiliation(s)
- Nicholas Denomme
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, 48109 United States; Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan, 48109 United States
| | - April L Lukowski
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, 48109 United States; Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, 48109 United States
| | - Jacob M Hull
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, 48109 United States
| | - Margaret B Jameson
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, 48109 United States; Molecular and Cellular Pharmacology Training Program, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 United States
| | - Alexandra A Bouza
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, 48109 United States
| | - Alison R H Narayan
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, 48109 United States; Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, 48109 United States; Department of Chemistry, University of Michigan, Ann Arbor, Michigan, 48109 United States
| | - Lori L Isom
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, 48109 United States; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, 48109 United States; Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, 48109 United States; Department of Neurology, University of Michigan, Ann Arbor, Michigan, 48109 United States.
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30
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Brunklaus A, Du J, Steckler F, Ghanty II, Johannesen KM, Fenger CD, Schorge S, Baez-Nieto D, Wang HR, Allen A, Pan JQ, Lerche H, Heyne H, Symonds JD, Zuberi SM, Sanders S, Sheidley BR, Craiu D, Olson HE, Weckhuysen S, DeJonge P, Helbig I, Van Esch H, Busa T, Milh M, Isidor B, Depienne C, Poduri A, Campbell AJ, Dimidschstein J, Møller RS, Lal D. Biological concepts in human sodium channel epilepsies and their relevance in clinical practice. Epilepsia 2020; 61:387-399. [PMID: 32090326 DOI: 10.1111/epi.16438] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/06/2020] [Accepted: 01/06/2020] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Voltage-gated sodium channels (SCNs) share similar amino acid sequence, structure, and function. Genetic variants in the four human brain-expressed SCN genes SCN1A/2A/3A/8A have been associated with heterogeneous epilepsy phenotypes and neurodevelopmental disorders. To better understand the biology of seizure susceptibility in SCN-related epilepsies, our aim was to determine similarities and differences between sodium channel disorders, allowing us to develop a broader perspective on precision treatment than on an individual gene level alone. METHODS We analyzed genotype-phenotype correlations in large SCN-patient cohorts and applied variant constraint analysis to identify severe sodium channel disease. We examined temporal patterns of human SCN expression and correlated functional data from in vitro studies with clinical phenotypes across different sodium channel disorders. RESULTS Comparing 865 epilepsy patients (504 SCN1A, 140 SCN2A, 171 SCN8A, four SCN3A, 46 copy number variation [CNV] cases) and analysis of 114 functional studies allowed us to identify common patterns of presentation. All four epilepsy-associated SCN genes demonstrated significant constraint in both protein truncating and missense variation when compared to other SCN genes. We observed that age at seizure onset is related to SCN gene expression over time. Individuals with gain-of-function SCN2A/3A/8A missense variants or CNV duplications share similar characteristics, most frequently present with early onset epilepsy (<3 months), and demonstrate good response to sodium channel blockers (SCBs). Direct comparison of corresponding SCN variants across different SCN subtypes illustrates that the functional effects of variants in corresponding channel locations are similar; however, their clinical manifestation differs, depending on their role in different types of neurons in which they are expressed. SIGNIFICANCE Variant function and location within one channel can serve as a surrogate for variant effects across related sodium channels. Taking a broader view on precision treatment suggests that in those patients with a suspected underlying genetic epilepsy presenting with neonatal or early onset seizures (<3 months), SCBs should be considered.
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Affiliation(s)
- Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Juanjiangmeng Du
- Cologne Center for Genomics, University of Cologne, University Hospital Cologne, Cologne, Germany
| | - Felix Steckler
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Ismael I Ghanty
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Katrine M Johannesen
- Deparment of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Christina Dühring Fenger
- Deparment of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Amplexa Genetics, Odense, Denmark
| | - Stephanie Schorge
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.,School of Pharmacy, University College London, London, UK
| | - David Baez-Nieto
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Hao-Ran Wang
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Andrew Allen
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Jen Q Pan
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
| | - Henrike Heyne
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts.,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts.,Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Joseph D Symonds
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Stephan Sanders
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Beth R Sheidley
- Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Dana Craiu
- Carol Davila University of Medicine, Department of Clinical Neurosciences, Pediatric Neurology Discipline, Bucharest, Romania.,Alexandru Obregia Hospital, Pediatric Neurology Clinic, Bucharest, Romania
| | - Heather E Olson
- Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Sarah Weckhuysen
- Neurogenetics Group, Center for Molecular Neurology, VIB, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Peter DeJonge
- Neurogenetics Group, Center for Molecular Neurology, VIB, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Neuropediatrics, University of Kiel, Kiel, Germany
| | - Hilde Van Esch
- Department of Human Genetics and Center for Human Genetics, Laboratory for Genetics of Cognition, University Hospitals Leuven, Leuven, Belgium
| | - Tiffany Busa
- Genetics Department, Timone Enfants University Hospital Center, Public Assistance-Marseille Hospitals, Marseille, France
| | - Matthieu Milh
- Medical Genetics and Functional Genomics, National Institute of Health and Medical Research, Mixed Unit of Research S910, Aix-Marseille University, Marseille, France.,Hematology Laboratory, Le Mans Hospital Center, Le Mans, France
| | - Bertrand Isidor
- Medical Genetics Department, Nantes University Hospital Center, Nantes, France
| | - Christel Depienne
- Institute of Human Genetics, Essen University Hospital, Essen, Germany.,Brain and Spinal Cord Institute, National Institute of Health and Medical Research, Unit 1127, National Center for Scientific Research, Mixed Unit of Research 7225, Sorbonne Universities, Pierre and Marie Curie University, Mixed Unit of Research S 1127, Brain & Spine Institute, Paris, France
| | - Annapurna Poduri
- Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.,Harvard Medical School, Boston, Massachusetts
| | | | - Jordane Dimidschstein
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Rikke S Møller
- Deparment of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Dennis Lal
- Cologne Center for Genomics, University of Cologne, University Hospital Cologne, Cologne, Germany.,Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts.,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio.,Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
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31
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Colasante G, Lignani G, Brusco S, Di Berardino C, Carpenter J, Giannelli S, Valassina N, Bido S, Ricci R, Castoldi V, Marenna S, Church T, Massimino L, Morabito G, Benfenati F, Schorge S, Leocani L, Kullmann DM, Broccoli V. dCas9-Based Scn1a Gene Activation Restores Inhibitory Interneuron Excitability and Attenuates Seizures in Dravet Syndrome Mice. Mol Ther 2020; 28:235-253. [PMID: 31607539 PMCID: PMC6952031 DOI: 10.1016/j.ymthe.2019.08.018] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 01/05/2023] Open
Abstract
Dravet syndrome (DS) is a severe epileptic encephalopathy caused mainly by heterozygous loss-of-function mutations of the SCN1A gene, indicating haploinsufficiency as the pathogenic mechanism. Here we tested whether catalytically dead Cas9 (dCas9)-mediated Scn1a gene activation can rescue Scn1a haploinsufficiency in a mouse DS model and restore physiological levels of its gene product, the Nav1.1 voltage-gated sodium channel. We screened single guide RNAs (sgRNAs) for their ability to stimulate Scn1a transcription in association with the dCas9 activation system. We identified a specific sgRNA that increases Scn1a gene expression levels in cell lines and primary neurons with high specificity. Nav1.1 protein levels were augmented, as was the ability of wild-type immature GABAergic interneurons to fire action potentials. A similar enhancement of Scn1a transcription was achieved in mature DS interneurons, rescuing their ability to fire. To test the therapeutic potential of this approach, we delivered the Scn1a-dCas9 activation system to DS pups using adeno-associated viruses. Parvalbumin interneurons recovered their firing ability, and febrile seizures were significantly attenuated. Our results pave the way for exploiting dCas9-based gene activation as an effective and targeted approach to DS and other disorders resulting from altered gene dosage.
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Affiliation(s)
- Gaia Colasante
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy.
| | - Gabriele Lignani
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Simone Brusco
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Claudia Di Berardino
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Jenna Carpenter
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Serena Giannelli
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Nicholas Valassina
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Simone Bido
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Raffaele Ricci
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Valerio Castoldi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Silvia Marenna
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Timothy Church
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Luca Massimino
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Giuseppe Morabito
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genova, Italy; IRCCS Ospedale Policlinico San Martino, University of Genova, 16132 Genova, Italy
| | - Stephanie Schorge
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Letizia Leocani
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Dimitri M Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Vania Broccoli
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy; CNR Institute of Neuroscience, 20129 Milan, Italy.
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Bartolini E, Campostrini R, Kiferle L, Pradella S, Rosati E, Chinthapalli K, Palumbo P. Epilepsy and brain channelopathies from infancy to adulthood. Neurol Sci 2019; 41:749-761. [PMID: 31838630 DOI: 10.1007/s10072-019-04190-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 12/06/2019] [Indexed: 01/04/2023]
Abstract
Genetic brain channelopathies result from inherited or de novo mutations of genes encoding ion channel subunits within the central nervous system. Most neurological channelopathies arise in childhood with paroxysmal or episodic symptoms, likely because of a transient impairment of homeostatic mechanisms regulating membrane excitability, and the prototypical expression of this impairment is epilepsy. Migraine, episodic ataxia and alternating hemiplegia can also occur, as well as chronic phenotypes, such as spinocerebellar ataxias, intellectual disability and autism spectrum disorder. Voltage-gated and ligand-gated channels may be involved. In most cases, a single gene may be associated with a phenotypical spectrum that shows variable expressivity. Different clinical features may arise at different ages and the adult phenotype may be remarkably modified from the syndrome onset in childhood or adolescence. Recognizing the prominent phenotypical traits of brain channelopathies is essential to perform appropriate diagnostic investigations and to provide the better care not only in the paediatric setting but also for adult patients and their caregivers. Herein, we provide an overview of genetic brain channelopathies associated with epilepsy, highlight the different molecular mechanisms and describe the different clinical characteristics which may prompt the clinician to suspect specific syndromes and to possibly establish tailored treatments.
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Affiliation(s)
- Emanuele Bartolini
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy.
| | - Roberto Campostrini
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | - Lorenzo Kiferle
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | - Silvia Pradella
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | - Eleonora Rosati
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | | | - Pasquale Palumbo
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
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Friedrich SR, Lovell PV, Kaser TM, Mello CV. Exploring the molecular basis of neuronal excitability in a vocal learner. BMC Genomics 2019; 20:629. [PMID: 31375088 PMCID: PMC6679542 DOI: 10.1186/s12864-019-5871-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/31/2019] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Vocal learning, the ability to learn to produce vocalizations through imitation, relies on specialized brain circuitry known in songbirds as the song system. While the connectivity and various physiological properties of this system have been characterized, the molecular genetic basis of neuronal excitability in song nuclei remains understudied. We have focused our efforts on examining voltage-gated ion channels to gain insight into electrophysiological and functional features of vocal nuclei. A previous investigation of potassium channel genes in zebra finches (Taeniopygia guttata) revealed evolutionary modifications unique to songbirds, as well as transcriptional specializations in the song system [Lovell PV, Carleton JB, Mello CV. BMC Genomics 14:470 2013]. Here, we expand this approach to sodium, calcium, and chloride channels along with their modulatory subunits using comparative genomics and gene expression analysis encompassing microarrays and in situ hybridization. RESULTS We found 23 sodium, 38 calcium, and 33 chloride channel genes (HGNC-based classification) in the zebra finch genome, several of which were previously unannotated. We determined 15 genes are missing relative to mammals, including several genes (CLCAs, BEST2) linked to olfactory transduction. The majority of sodium and calcium but few chloride channels showed differential expression in the song system, among them SCN8A and CACNA1E in the direct motor pathway, and CACNG4 and RYR2 in the anterior forebrain pathway. In several cases, we noted a seemingly coordinated pattern across multiple nuclei (SCN1B, SCN3B, SCN4B, CACNB4) or sparse expression (SCN1A, CACNG5, CACNA1B). CONCLUSION The gene families examined are highly conserved between avian and mammalian lineages. Several cases of differential expression likely support high-frequency and burst firing in specific song nuclei, whereas cases of sparse patterns of expression may contribute to the unique electrophysiological signatures of distinct cell populations. These observations lay the groundwork for manipulations to determine how ion channels contribute to the neuronal excitability properties of vocal learning systems.
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Affiliation(s)
- Samantha R. Friedrich
- Department of Behavioral Neuroscience, Oregon Health and Science University, 3181 Sam Jackson Park Rd L470, Portland, OR USA
| | - Peter V. Lovell
- Department of Behavioral Neuroscience, Oregon Health and Science University, 3181 Sam Jackson Park Rd L470, Portland, OR USA
| | - Taylor M. Kaser
- Department of Behavioral Neuroscience, Oregon Health and Science University, 3181 Sam Jackson Park Rd L470, Portland, OR USA
| | - Claudio V. Mello
- Department of Behavioral Neuroscience, Oregon Health and Science University, 3181 Sam Jackson Park Rd L470, Portland, OR USA
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Hippocampal deletion of Na V1.1 channels in mice causes thermal seizures and cognitive deficit characteristic of Dravet Syndrome. Proc Natl Acad Sci U S A 2019; 116:16571-16576. [PMID: 31346088 DOI: 10.1073/pnas.1906833116] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dravet Syndrome is a severe childhood epileptic disorder caused by haploinsufficiency of the SCN1A gene encoding brain voltage-gated sodium channel NaV1.1. Symptoms include treatment-refractory epilepsy, cognitive impairment, autistic-like behavior, and premature death. The specific loci of NaV1.1 function in the brain that underlie these global deficits remain unknown. Here we specifically deleted Scn1a in the hippocampus using the Cre-Lox method in weanling mice. Local gene deletion caused selective reduction of inhibitory neurotransmission measured in dentate granule cells. Mice with local NaV1.1 reduction had thermally evoked seizures and spatial learning deficits, but they did not have abnormalities of locomotor activity or social interaction. Our results show that local gene deletion in the hippocampus can induce two of the most severe dysfunctions of Dravet Syndrome: Epilepsy and cognitive deficit. Considering these results, the hippocampus may be a potential target for future gene therapy for Dravet Syndrome.
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Strzelczyk A, Kalski M, Bast T, Wiemer-Kruel A, Bettendorf U, Kay L, Kieslich M, Kluger G, Kurlemann G, Mayer T, Neubauer BA, Polster T, Herting A, von Spiczak S, Trollmann R, Wolff M, Irwin J, Carroll J, Macdonald D, Pritchard C, Klein KM, Rosenow F, Schubert-Bast S. Burden-of-illness and cost-driving factors in Dravet syndrome patients and carers: A prospective, multicenter study from Germany. Eur J Paediatr Neurol 2019; 23:392-403. [PMID: 30871879 DOI: 10.1016/j.ejpn.2019.02.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/21/2019] [Accepted: 02/24/2019] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Dravet syndrome (DS) is a rare developmental and epileptic encephalopathy. This study estimated cost, cost-driving factors and quality of life (QoL) in patients with Dravet syndrome and their caregivers in a prospective, multicenter study in Germany. METHODS A validated 3-12-month retrospective questionnaire and a prospective 3-month diary assessing clinical characteristics, QoL, and direct, indirect and out-of-pocket (OOP) costs were administered to caregivers of patients with DS throughout Germany. RESULTS Caregivers of 93 patients (mean age 10.1 years, ±7.1, range 15 months-33.7 years) submitted questionnaires and 77 prospective diaries. The majority of patients (95%) experienced at least one seizure during the previous 12 months and 77% a status epilepticus (SE) at least once in their lives. Over 70% of patients had behavioural problems and delayed speech development and over 80% attention deficit symptoms and disturbance of motor skills and movement coordination. Patient QoL was lower than in the general population and 45% of caregivers had some form of depressive symptoms. Direct health care costs per three months were a mean of €6,043 ± €5,825 (median €4054, CI €4935-€7350) per patient. Inpatient costs formed the single most important cost category (28%, €1,702 ± €4,315), followed by care grade benefits (19%, €1,130 ± €805), anti-epileptic drug (AED) costs (15%, €892 ± €1,017) and ancillary treatments (9%, €559 ± €503). Total indirect costs were €4,399 ±€ 4,989 (median €0, CI €3466-€5551) in mothers and €391 ± €1,352 (median €0, CI €195-€841) in fathers. In univariate analysis seizure frequency, experience of SE, nursing care level and severe additional symptoms were found to be associated with total direct healthcare costs. Severe additional symptoms was the single independently significant explanatory factor in a multivariate analysis. CONCLUSIONS This study over a period up to 15 months revealed substantial direct and indirect healthcare costs of DS in Germany and highlights the relatively low patient and caregiver QoL compared with the general population.
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Affiliation(s)
- Adam Strzelczyk
- Epilepsy Center Frankfurt Rhine-Main and Department of Neurology, Goethe-University, Frankfurt am Main, Germany; Epilepsy Center Hessen and Department of Neurology, Philipps-University Marburg, Marburg, Germany; LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University, Frankfurt am Main, Germany.
| | - Malin Kalski
- Epilepsy Center Frankfurt Rhine-Main and Department of Neurology, Goethe-University, Frankfurt am Main, Germany
| | - Thomas Bast
- Epilepsy Center Kork, Kehl-Kork, Germany; Faculty of Medicine, University of Freiburg, Germany
| | | | | | - Lara Kay
- Epilepsy Center Frankfurt Rhine-Main and Department of Neurology, Goethe-University, Frankfurt am Main, Germany; LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University, Frankfurt am Main, Germany
| | - Matthias Kieslich
- Epilepsy Center Frankfurt Rhine-Main and Department of Neurology, Goethe-University, Frankfurt am Main, Germany; Department of Neuropediatrics, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Gerhard Kluger
- Clinic for Neuropediatrics and Neurorehabilitation, Epilepsy Center for Children and Adolescents, Schön Klinik Vogtareuth, Germany; Research Institute "Rehabilitation, Transition, and Palliation", PMU Salzburg, Salzburg, Austria
| | - Gerhard Kurlemann
- Department of Neuropediatrics, University of Münster, Münster, Germany
| | - Thomas Mayer
- Epilepsy Center Kleinwachau, Dresden-Radeberg, Germany
| | - Bernd A Neubauer
- Department of Neuropediatrics, Justus-Liebig-University Giessen, Giessen, Germany
| | | | | | - Sarah von Spiczak
- Northern German Epilepsy Centre for Children and Adolescents, Kiel-Raisdorf, Germany
| | - Regina Trollmann
- Department of Neuropediatrics, Friedrich-Alexander University, Erlangen, Germany
| | - Markus Wolff
- Department of Neuropediatrics, University of Tübingen, Tübingen, Germany
| | - John Irwin
- Zogenix International Limited, Maidenhead, United Kingdom
| | | | | | | | - Karl Martin Klein
- Epilepsy Center Frankfurt Rhine-Main and Department of Neurology, Goethe-University, Frankfurt am Main, Germany; LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University, Frankfurt am Main, Germany; Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Felix Rosenow
- Epilepsy Center Frankfurt Rhine-Main and Department of Neurology, Goethe-University, Frankfurt am Main, Germany; LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University, Frankfurt am Main, Germany
| | - Susanne Schubert-Bast
- Epilepsy Center Frankfurt Rhine-Main and Department of Neurology, Goethe-University, Frankfurt am Main, Germany; LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University, Frankfurt am Main, Germany; Department of Neuropediatrics, Goethe-University Frankfurt, Frankfurt am Main, Germany
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Kumar V, Prakash C, Singh R, Sharma D. Curcumin's antiepileptic effect, and alterations in Na v1.1 and Na v1.6 expression in iron-induced epilepsy. Epilepsy Res 2018; 150:7-16. [PMID: 30605865 DOI: 10.1016/j.eplepsyres.2018.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 12/08/2018] [Accepted: 12/14/2018] [Indexed: 10/27/2022]
Abstract
The present study was carried out to evaluate: the antiepileptic effect of dietary curcumin, and the effect of epileptic state and curcumin on the molecular expression of voltage-activated Na+ channel subtypes Nav1.1 and Nav1.6 in the iron-induced experimental epilepsy in the rat. Rats were divided into four groups; Group I (control rats), Group II (epileptic rats), Group III (curcumin-fed epileptic rats), and Group IV (curcumin-fed rats). Curcumin was fed chronically to rats approximately at the dose of 100 mg/kg body wt. The animals were made epileptic by intracortical injection of FeCl3. The mRNA and protein expressions of Nav1.1 and Nav1.6 were examined by RT-PCR analysis and immuno-histochemistry. Results showed a significant increase (upregulation) in the expression of both Nav1.1 and Nav1.6 with seizure activity in the cortex and hippocampus of epileptic rats. Epileptic rats fed with curcumin showed a marked decrease in epileptiform activity, and reduced mRNA and protein levels of Nav1.1. It appears that the antiepileptic action of curcumin may be associated with the downregulation of Nav1.1 in the cortex.
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Affiliation(s)
- Vikas Kumar
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Chandra Prakash
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Rameshwar Singh
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Deepak Sharma
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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Selective Na V1.1 activation rescues Dravet syndrome mice from seizures and premature death. Proc Natl Acad Sci U S A 2018; 115:E8077-E8085. [PMID: 30076230 PMCID: PMC6112713 DOI: 10.1073/pnas.1804764115] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Spider venom is a rich source of peptides, many targeting ion channels. We assessed a venom peptide, Hm1a, as a potential targeted therapy for Dravet syndrome, the genetic epilepsy linked to a mutation in the gene encoding the sodium channel alpha subunit NaV1.1. Cell-based assays showed Hm1a was selective for hNaV1.1 over other sodium and potassium channels. Utilizing a mouse model of Dravet syndrome, Hm1a restored inhibitory neuron function and significantly reduced seizures and mortality in heterozygote mice. Evidence from the structure of Hm1a and modeling suggest Hm1a interacts with NaV1.1 inactivation domains, providing a structural correlate of the functional mechanisms. This proof-of-concept study provides a promising strategy for future drug development in genetic epilepsy and other neurogenetic disorders. Dravet syndrome is a catastrophic, pharmacoresistant epileptic encephalopathy. Disease onset occurs in the first year of life, followed by developmental delay with cognitive and behavioral dysfunction and substantially elevated risk of premature death. The majority of affected individuals harbor a loss-of-function mutation in one allele of SCN1A, which encodes the voltage-gated sodium channel NaV1.1. Brain NaV1.1 is primarily localized to fast-spiking inhibitory interneurons; thus the mechanism of epileptogenesis in Dravet syndrome is hypothesized to be reduced inhibitory neurotransmission leading to brain hyperexcitability. We show that selective activation of NaV1.1 by venom peptide Hm1a restores the function of inhibitory interneurons from Dravet syndrome mice without affecting the firing of excitatory neurons. Intracerebroventricular infusion of Hm1a rescues Dravet syndrome mice from seizures and premature death. This precision medicine approach, which specifically targets the molecular deficit in Dravet syndrome, presents an opportunity for treatment of this intractable epilepsy.
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Goldberg EM, Helbig I. Reply to “Recurrent SCN3A
p.Ile875Thr variant in patients with polymicrogyria”. Ann Neurol 2018; 84:161. [DOI: 10.1002/ana.25254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/16/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Ethan M. Goldberg
- Division of Neurology, Department of Pediatrics; Children's Hospital of Philadelphia; Philadelphia PA
- Department of Neurology, Perelman School of Medicine at University of Pennsylvania; Philadelphia PA
- Department of Neuroscience; Perelman School of Medicine at University of Pennsylvania; Philadelphia PA
| | - Ingo Helbig
- Division of Neurology, Department of Pediatrics; Children's Hospital of Philadelphia; Philadelphia PA
- Department of Neurology, Perelman School of Medicine at University of Pennsylvania; Philadelphia PA
- Department of Neuropediatrics; University Medical Center Schleswig-Holstein, Christian Albrechts University; Kiel Germany
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Abnormal changes in voltage-gated sodium channels subtypes Na V 1.1, Na V 1.2, Na V 1.3, Na V 1.6 and CaM/CaMKII pathway in low-grade astrocytoma. Neurosci Lett 2018; 674:148-155. [DOI: 10.1016/j.neulet.2018.03.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 03/20/2018] [Accepted: 03/20/2018] [Indexed: 12/19/2022]
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Abstract
Dravet Syndrome is a devastating childhood epilepsy disorder with high incidence of premature death plus comorbidities of ataxia, circadian rhythm disorder, impaired sleep quality, autistic-like social-interaction deficits and severe cognitive impairment. It is primarily caused by heterozygous loss-of-function mutations in the SCN1A gene that encodes brain voltage-gated sodium channel type-1, termed NaV1.1. Here I review experiments on mouse genetic models that implicate specific loss of sodium currents and action potential firing in GABAergic inhibitory interneurons as the fundamental cause of Dravet Syndrome. The resulting imbalance of excitatory to inhibitory neurotransmission in neural circuits causes both epilepsy and co-morbidities. Promising therapeutic approaches involving atypical sodium channel blockers, novel drug combinations, and cannabidiol give hope for improved outcomes for Dravet Syndrome patients.
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Affiliation(s)
- William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280 USA
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Zaman T, Helbig I, Božović IB, DeBrosse SD, Bergqvist AC, Wallis K, Medne L, Maver A, Peterlin B, Helbig KL, Zhang X, Goldberg EM. Mutations in SCN3A cause early infantile epileptic encephalopathy. Ann Neurol 2018; 83:703-717. [PMID: 29466837 DOI: 10.1002/ana.25188] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 02/01/2018] [Accepted: 02/18/2018] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Voltage-gated sodium (Na+ ) channels underlie action potential generation and propagation and hence are central to the regulation of excitability in the nervous system. Mutations in the genes SCN1A, SCN2A, and SCN8A, encoding the Na+ channel pore-forming (α) subunits Nav1.1, 1.2, and 1.6, respectively, and SCN1B, encoding the accessory subunit β1 , are established causes of genetic epilepsies. SCN3A, encoding Nav1.3, is known to be highly expressed in brain, but has not previously been linked to early infantile epileptic encephalopathy. Here, we describe a cohort of 4 patients with epileptic encephalopathy and heterozygous de novo missense variants in SCN3A (p.Ile875Thr in 2 cases, p.Pro1333Leu, and p.Val1769Ala). METHODS All patients presented with treatment-resistant epilepsy in the first year of life, severe to profound intellectual disability, and in 2 cases (both with the variant p.Ile875Thr), diffuse polymicrogyria. RESULTS Electrophysiological recordings of mutant channels revealed prominent gain of channel function, with a markedly increased amplitude of the slowly inactivating current component, and for 2 of 3 mutants (p.Ile875Thr and p.Pro1333Leu), a leftward shift in the voltage dependence of activation to more hyperpolarized potentials. Gain of function was not observed for Nav1.3 variants known or presumed to be inherited (p.Arg1642Cys and p.Lys1799Gln). The antiseizure medications phenytoin and lacosamide selectively blocked slowly inactivating over transient current in wild-type and mutant Nav1.3 channels. INTERPRETATION These findings establish SCN3A as a new gene for infantile epileptic encephalopathy and suggest a potential pharmacologic intervention. These findings also reinforce the role of Nav1.3 as an important regulator of neuronal excitability in the developing brain, while providing additional insight into mechanisms of slow inactivation of Nav1.3. Ann Neurol 2018;83:703-717.
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Affiliation(s)
- Tariq Zaman
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Ingo Helbig
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Christian Albrecht University, Kiel, Germany.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ivana Babić Božović
- Department of Biology and Medical Genetics, School of Medicine, University of Rijeka, Rijeka, Croatia
| | - Suzanne D DeBrosse
- Departments of Genetics and Genome Sciences, Pediatrics, and Neurology, and Center for Human Genetics, Case Western Reserve University School of Medicine, Cleveland, OH
| | - A Christina Bergqvist
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Kimberly Wallis
- Departments of Genetics and Genome Sciences, Pediatrics, and Neurology, and Center for Human Genetics, Case Western Reserve University School of Medicine, Cleveland, OH
| | - Livija Medne
- Division of Human Genetics, Department of Pediatrics, Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Aleš Maver
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Borut Peterlin
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Katherine L Helbig
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA.,Division of Clinical Genomics, Ambry Genetics, Aliso Viejo, CA
| | - Xiaohong Zhang
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Ethan M Goldberg
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.,Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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Maljevic S, Reid CA, Petrou S. Models for discovery of targeted therapy in genetic epileptic encephalopathies. J Neurochem 2017; 143:30-48. [PMID: 28742937 DOI: 10.1111/jnc.14134] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/14/2017] [Accepted: 07/19/2017] [Indexed: 12/20/2022]
Abstract
Epileptic encephalopathies are severe disorders emerging in the first days to years of life that commonly include refractory seizures, various types of movement disorders, and different levels of developmental delay. In recent years, many de novo occurring variants have been identified in individuals with these devastating disorders. To unravel disease mechanisms, the functional impact of detected variants associated with epileptic encephalopathies is investigated in a range of cellular and animal models. This review addresses efforts to advance and use such models to identify specific molecular and cellular targets for the development of novel therapies. We focus on ion channels as the best-studied group of epilepsy genes. Given the clinical and genetic heterogeneity of epileptic encephalopathy disorders, experimental models that can reflect this complexity are critical for the development of disease mechanisms-based targeted therapy. The convergence of technological advances in gene sequencing, stem cell biology, genome editing, and high throughput functional screening together with massive unmet clinical needs provides unprecedented opportunities and imperatives for precision medicine in epileptic encephalopathies.
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Affiliation(s)
- Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia.,University of Melbourne, Melbourne, Australia
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Lamar T, Vanoye CG, Calhoun J, Wong JC, Dutton SBB, Jorge BS, Velinov M, Escayg A, Kearney JA. SCN3A deficiency associated with increased seizure susceptibility. Neurobiol Dis 2017; 102:38-48. [PMID: 28235671 DOI: 10.1016/j.nbd.2017.02.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 01/24/2017] [Accepted: 02/20/2017] [Indexed: 11/25/2022] Open
Abstract
Mutations in voltage-gated sodium channels expressed highly in the brain (SCN1A, SCN2A, SCN3A, and SCN8A) are responsible for an increasing number of epilepsy syndromes. In particular, mutations in the SCN3A gene, encoding the pore-forming Nav1.3 α subunit, have been identified in patients with focal epilepsy. Biophysical characterization of epilepsy-associated SCN3A variants suggests that both gain- and loss-of-function SCN3A mutations may lead to increased seizure susceptibility. In this report, we identified a novel SCN3A variant (L247P) by whole exome sequencing of a child with focal epilepsy, developmental delay, and autonomic nervous system dysfunction. Voltage clamp analysis showed no detectable sodium current in a heterologous expression system expressing the SCN3A-L247P variant. Furthermore, cell surface biotinylation demonstrated a reduction in the amount of SCN3A-L247P at the cell surface, suggesting the SCN3A-L247P variant is a trafficking-deficient mutant. To further explore the possible clinical consequences of reduced SCN3A activity, we investigated the effect of a hypomorphic Scn3a allele (Scn3aHyp) on seizure susceptibility and behavior using a gene trap mouse line. Heterozygous Scn3a mutant mice (Scn3a+/Hyp) did not exhibit spontaneous seizures nor were they susceptible to hyperthermia-induced seizures. However, they displayed increased susceptibility to electroconvulsive (6Hz) and chemiconvulsive (flurothyl and kainic acid) induced seizures. Scn3a+/Hyp mice also exhibited deficits in locomotor activity and motor learning. Taken together, these results provide evidence that loss-of-function of SCN3A caused by reduced protein expression or deficient trafficking to the plasma membrane may contribute to increased seizure susceptibility.
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Affiliation(s)
- Tyra Lamar
- Department of Human Genetics, Emory University, Atlanta, GA, USA
| | - Carlos G Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jeffrey Calhoun
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, GA, USA
| | | | - Benjamin S Jorge
- Neuroscience Program, Vanderbilt University, Nashville, TN 37232, USA
| | - Milen Velinov
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA; Albert Einstein College of Medicine, Bronx, NY, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA, USA.
| | - Jennifer A Kearney
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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44
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Abstract
Dravet syndrome is one of the most severe epilepsy syndromes of early childhood, and it comes with very high morbidity and mortality. The typical presentation is characterized by hemiclonic or generalized clonic seizures triggered by fever during the first year of life, followed by myoclonic, absence, focal and generalized tonic-clonic seizures. Non-convulsive status epilepticus and epileptic encephalopathy are common. Development is normal in the first year of life, but most individuals eventually suffer from intellectual impairment. Dravet syndrome is associated with mutations in the sodium channel alpha1 subunit gene (SCN1A) in 70-80% of individuals. SCN1A mutation results in inhibition of the GABAergic inhibitory interneurons, leading to excessive neuronal excitation. The "interneuron hypothesis" is the current most accepted pathophysiological mechanism of Dravet syndrome. The mortality rate is increased significantly in Dravet syndrome. Ataxia, a characteristic crouched gait and Parkinson's symptoms may develop in some individuals. It is likely that Dravet syndrome is underdiagnosed in adults with treatment-resistant epilepsy. Early diagnosis is important to avoid anti-seizure medications that exacerbate seizures.
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45
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Okuda H, Noguchi A, Kobayashi H, Kondo D, Harada KH, Youssefian S, Shioi H, Kabata R, Domon Y, Kubota K, Kitano Y, Takayama Y, Hitomi T, Ohno K, Saito Y, Asano T, Tominaga M, Takahashi T, Koizumi A. Infantile Pain Episodes Associated with Novel Nav1.9 Mutations in Familial Episodic Pain Syndrome in Japanese Families. PLoS One 2016; 11:e0154827. [PMID: 27224030 PMCID: PMC4880298 DOI: 10.1371/journal.pone.0154827] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 04/19/2016] [Indexed: 12/19/2022] Open
Abstract
Painful peripheral neuropathy has been correlated with various voltage-gated sodium channel mutations in sensory neurons. Recently Nav1.9, a voltage-gated sodium channel subtype, has been established as a genetic influence for certain peripheral pain syndromes. In this study, we performed a genetic study in six unrelated multigenerational Japanese families with episodic pain syndrome. Affected participants (n = 23) were characterized by infantile recurrent pain episodes with spontaneous mitigation around adolescence. This unique phenotype was inherited in an autosomal-dominant mode. Linkage analysis was performed for two families with 12 affected and nine unaffected members, and a single locus was identified on 3p22 (LOD score 4.32). Exome analysis (n = 14) was performed for affected and unaffected members in these two families and an additional family. Two missense variants were identified: R222H and R222S in SCN11A. Next, we generated a knock-in mouse model harboring one of the mutations (R222S). Behavioral tests (Hargreaves test and cold plate test) using R222S and wild-type C57BL/6 (WT) mice, young (8-9 weeks old; n = 10-12 for each group) and mature (36-38 weeks old; n = 5-6 for each group), showed that R222S mice were significantly (p < 0.05) more hypersensitive to hot and cold stimuli than WT mice. Electrophysiological studies using dorsal root ganglion neurons from 8-9-week-old mice showed no significant difference in resting membrane potential, but input impedance and firing frequency of evoked action potentials were significantly increased in R222S mice compared with WT mice. However, there was no significant difference among Nav1.9 (WT, R222S, and R222H)-overexpressing ND7/23 cell lines. These results suggest that our novel mutation is a gain-of-function mutation that causes infantile familial episodic pain. The mouse model developed here will be useful for drug screening for familial episodic pain syndrome associated with SCN11A mutations.
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Affiliation(s)
- Hiroko Okuda
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Atsuko Noguchi
- Department of Pediatrics, Akita University School of Medicine, Akita, Japan
| | - Hatasu Kobayashi
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Daiki Kondo
- Department of Pediatrics, Akita University School of Medicine, Akita, Japan
| | - Kouji H. Harada
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shohab Youssefian
- Laboratory of Molecular Biosciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hirotomo Shioi
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Risako Kabata
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yuki Domon
- Biological Research Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa-ku, Tokyo, Japan
| | - Kazufumi Kubota
- Biological Research Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa-ku, Tokyo, Japan
| | - Yutaka Kitano
- Biological Research Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa-ku, Tokyo, Japan
| | - Yasunori Takayama
- Okazaki Institute for Integrative Bioscience, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Aichi, Japan
| | - Toshiaki Hitomi
- Department of Preventive Medicine, St. Marianna University School of Medicine, Kanagawa, Japan
| | - Kousaku Ohno
- Department of Pediatrics, Sanin Rosai Hospital, Tottori, Japan
| | - Yoshiaki Saito
- Division of Child Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, Tottori, Japan
| | - Takeshi Asano
- Department of Pediatrics, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
| | - Makoto Tominaga
- Okazaki Institute for Integrative Bioscience, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Aichi, Japan
| | - Tsutomu Takahashi
- Department of Pediatrics, Akita University School of Medicine, Akita, Japan
- * E-mail: (AK); (TT)
| | - Akio Koizumi
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- * E-mail: (AK); (TT)
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Hsiao J, Yuan TY, Tsai MS, Lu CY, Lin YC, Lee ML, Lin SW, Chang FC, Liu Pimentel H, Olive C, Coito C, Shen G, Young M, Thorne T, Lawrence M, Magistri M, Faghihi MA, Khorkova O, Wahlestedt C. Upregulation of Haploinsufficient Gene Expression in the Brain by Targeting a Long Non-coding RNA Improves Seizure Phenotype in a Model of Dravet Syndrome. EBioMedicine 2016; 9:257-277. [PMID: 27333023 PMCID: PMC4972487 DOI: 10.1016/j.ebiom.2016.05.011] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/02/2016] [Accepted: 05/09/2016] [Indexed: 02/07/2023] Open
Abstract
Dravet syndrome is a devastating genetic brain disorder caused by heterozygous loss-of-function mutation in the voltage-gated sodium channel gene SCN1A. There are currently no treatments, but the upregulation of SCN1A healthy allele represents an appealing therapeutic strategy. In this study we identified a novel, evolutionary conserved mechanism controlling the expression of SCN1A that is mediated by an antisense non-coding RNA (SCN1ANAT). Using oligonucleotide-based compounds (AntagoNATs) targeting SCN1ANAT we were able to induce specific upregulation of SCN1A both in vitro and in vivo, in the brain of Dravet knock-in mouse model and a non-human primate. AntagoNAT-mediated upregulation of Scn1a in postnatal Dravet mice led to significant improvements in seizure phenotype and excitability of hippocampal interneurons. These results further elucidate the pathophysiology of Dravet syndrome and outline a possible new approach for the treatment of this and other genetic disorders with similar etiology.
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Affiliation(s)
- J Hsiao
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - T Y Yuan
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - M S Tsai
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University Hospital, College of Medicine, National Taiwan University, No. 1, Sec. 1, Jen-Ai Rd., Taipei 100, Taiwan
| | - C Y Lu
- Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan
| | - Y C Lin
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - M L Lee
- Dep. Clinical Laboratory Science and Medical Biotechnology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - S W Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University Hospital, College of Medicine, National Taiwan University, No. 1, Sec. 1, Jen-Ai Rd., Taipei 100, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, No. 7, Chung-Shan S. Rd., Taipei 100, Taiwan; Center for Genomic Medicine, National Taiwan University, No. 7, Chung-Shan S. Rd., Taipei 100, Taiwan
| | - F C Chang
- Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, No. 1, Sec. 1, Jen-Ai Rd., Taipei 100, Taiwan; Graduate Institute of Acupuncture Science, College of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - H Liu Pimentel
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - C Olive
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - C Coito
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - G Shen
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - M Young
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - T Thorne
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - M Lawrence
- RxGen, 100 Deepwood Drive, Hamden, CT 06517, USA
| | - M Magistri
- Center for Therapeutic Innovation and the Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Avenue, Miami 33136, FL, USA
| | - M A Faghihi
- Center for Therapeutic Innovation and the Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Avenue, Miami 33136, FL, USA
| | - O Khorkova
- OPKO Health Inc., 10320 USA Today Way, Miramar, FL 33025, USA
| | - C Wahlestedt
- Center for Therapeutic Innovation and the Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Avenue, Miami 33136, FL, USA.
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47
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Battaglia D, Ricci D, Chieffo D, Guzzetta F. Outlining a core neuropsychological phenotype for Dravet syndrome. Epilepsy Res 2016; 120:91-7. [DOI: 10.1016/j.eplepsyres.2015.11.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/15/2015] [Accepted: 11/27/2015] [Indexed: 11/16/2022]
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48
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Kazdoba TM, Leach PT, Crawley JN. Behavioral phenotypes of genetic mouse models of autism. GENES, BRAIN, AND BEHAVIOR 2016; 15:7-26. [PMID: 26403076 PMCID: PMC4775274 DOI: 10.1111/gbb.12256] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/27/2015] [Accepted: 09/18/2015] [Indexed: 12/11/2022]
Abstract
More than a hundred de novo single gene mutations and copy-number variants have been implicated in autism, each occurring in a small subset of cases. Mutant mouse models with syntenic mutations offer research tools to gain an understanding of the role of each gene in modulating biological and behavioral phenotypes relevant to autism. Knockout, knockin and transgenic mice incorporating risk gene mutations detected in autism spectrum disorder and comorbid neurodevelopmental disorders are now widely available. At present, autism spectrum disorder is diagnosed solely by behavioral criteria. We developed a constellation of mouse behavioral assays designed to maximize face validity to the types of social deficits and repetitive behaviors that are central to an autism diagnosis. Mouse behavioral assays for associated symptoms of autism, which include cognitive inflexibility, anxiety, hyperactivity, and unusual reactivity to sensory stimuli, are frequently included in the phenotypic analyses. Over the past 10 years, we and many other laboratories around the world have employed these and additional behavioral tests to phenotype a large number of mutant mouse models of autism. In this review, we highlight mouse models with mutations in genes that have been identified as risk genes for autism, which work through synaptic mechanisms and through the mTOR signaling pathway. Robust, replicated autism-relevant behavioral outcomes in a genetic mouse model lend credence to a causal role for specific gene contributions and downstream biological mechanisms in the etiology of autism.
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Affiliation(s)
- T. M. Kazdoba
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - P. T. Leach
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - J. N. Crawley
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
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Brunklaus A, Zuberi SM. Dravet syndrome--from epileptic encephalopathy to channelopathy. Epilepsia 2014; 55:979-84. [PMID: 24836964 DOI: 10.1111/epi.12652] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2014] [Indexed: 12/19/2022]
Abstract
Mutations in the gene encoding the α1 subunit of the voltage gated sodium channel (SCN1A) are associated with several epilepsy syndromes, ranging from relatively mild phenotypes found in families with genetic epilepsy with febrile seizures plus (GEFS+) to the severe infant-onset epilepsy Dravet syndrome. Evidence has emerged of the consequences of SCN1α dysfunction in different neuronal networks across the brain pointing toward a channelopathy model causing the neurologic features of Dravet syndrome that is beyond purely seizure related damage. A genetic change will present according to its severity, the genetic background of the individual, and environmental factors, and will affect a variety of neuronal networks according to channel distribution. This already-vulnerable system may be susceptible to secondary aggravating events such as status epilepticus. The channelopathy model implies that pharmacologic treatment and the restoration of impaired γ-aminobutyric acid (GABA)ergic neurotransmission might not only help prevent seizures but might affect the comorbidities of the syndrome. This critical review explores recent evidence relating to the pathogenicity of SCN1A mutations in Dravet syndrome and the effect these have on the wider disease phenotype and discusses whether knowledge of specific genotypes can influence clinical practice. Genetic technology is currently advancing at unprecedented speed and will increase our knowledge of new genes and interacting genetic networks. Clinicians and geneticists will have to work in close collaboration to guarantee good delivery and counseling of genetic testing results.
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Affiliation(s)
- Andreas Brunklaus
- The Paediatric Neurosciences Research Group, Royal Hospital for Sick Children, Glasgow, United Kingdom; College of Medicine, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
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