1
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Tang B, Zhao J, Zhang C, Qi P, Zheng S, Xu C, Chen M, Ye X. Dysregulation of parvalbumin expression and neurotransmitter imbalance in the auditory cortex of the BTBR mouse model of autism spectrum disorder. Dev Neurobiol 2024. [PMID: 39128889 DOI: 10.1002/dneu.22952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 05/01/2024] [Accepted: 07/15/2024] [Indexed: 08/13/2024]
Abstract
Individuals diagnosed with autism spectrum disorder (ASD) frequently exhibit abnormalities in auditory perception, a phenomenon potentially attributed to alterations in the excitatory and inhibitory cells constituting cortical circuits. However, the exact genetic factors and cell types affected by ASD remain unclear. The present study investigated the balance of excitatory and inhibitory activity in the auditory cortex using BTBR T+ Itpr3tf/J (BTBR) mice, a well-established model for autism research. Our investigation unveiled a reduction in parvalbumin-positive (PV+) neurons within the AC of BTBR mice. Remarkably, in vivo magnetic resonance spectroscopy studies disclosed an elevation in glutamate (Glu) levels alongside a decrement in γ-aminobutyric acid (GABA) levels in this cortical region. Additionally, transcriptomic analysis of the mouse model facilitated the classification of several ASD-associated genes based on their cellular function and pathways. By comparing autism risk genes with RNA transcriptome sequencing data from the ASD mouse model, we identified the recurrent target gene Scn1a and performed validation. Intriguingly, we uncovered the specific expression of Scn1a in cortical inhibitory neurons. These findings hold significant value for understanding the underlying neural mechanisms of abnormal sensory perception in animal models of ASD.
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Affiliation(s)
- Binliang Tang
- Center for Rehabilitation Medicine, Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Department of Rehabilitation Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, China
| | - Jingting Zhao
- Center for Rehabilitation Medicine, Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Department of Rehabilitation Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, China
| | - Cui Zhang
- Department of Pharmacology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Pengwei Qi
- Center for Rehabilitation Medicine, Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Department of Rehabilitation Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, China
| | - Shuyu Zheng
- The Fourth School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Chengyuan Xu
- Department of Pharmacology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Ming Chen
- Department of Pharmacology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Xiangming Ye
- Center for Rehabilitation Medicine, Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Department of Rehabilitation Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, China
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2
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Whyte-Fagundes PA, Vance A, Carroll A, Figueroa F, Manukyan C, Baraban SC. Testing of putative antiseizure medications in a preclinical Dravet syndrome zebrafish model. Brain Commun 2024; 6:fcae135. [PMID: 38707709 PMCID: PMC11069116 DOI: 10.1093/braincomms/fcae135] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 03/27/2024] [Accepted: 04/12/2024] [Indexed: 05/07/2024] Open
Abstract
Dravet syndrome is a severe genetic epilepsy primarily caused by de novo mutations in a voltage-activated sodium channel gene (SCN1A). Patients face life-threatening seizures that are largely resistant to available anti-seizure medications. Preclinical Dravet syndrome animal models are a valuable tool to identify candidate anti-seizure medications for these patients. Among these, scn1lab mutant zebrafish, exhibiting spontaneous seizure-like activity, are particularly amenable to large-scale drug screening. Thus far, we have screened more than 3000 drug candidates in scn1lab zebrafish mutants, identifying valproate, stiripentol, and fenfluramine e.g. Food and Drug Administration-approved drugs, with clinical application in the Dravet syndrome population. Successful phenotypic screening in scn1lab mutant zebrafish is rigorous and consists of two stages: (i) a locomotion-based assay measuring high-velocity convulsive swim behaviour and (ii) an electrophysiology-based assay, using in vivo local field potential recordings, to quantify electrographic seizure-like events. Historically, nearly 90% of drug candidates fail during translation from preclinical models to the clinic. With such a high failure rate, it becomes necessary to address issues of replication and false positive identification. Leveraging our scn1lab zebrafish assays is one approach to address these problems. Here, we curated a list of nine anti-seizure drug candidates recently identified by other groups using preclinical Dravet syndrome models: 1-Ethyl-2-benzimidazolinone, AA43279, chlorzoxazone, donepezil, lisuride, mifepristone, pargyline, soticlestat and vorinostat. First-stage locomotion-based assays in scn1lab mutant zebrafish identified only 1-Ethyl-2-benzimidazolinone, chlorzoxazone and lisuride. However, second-stage local field potential recording assays did not show significant suppression of spontaneous electrographic seizure activity for any of the nine anti-seizure drug candidates. Surprisingly, soticlestat induced frank electrographic seizure-like discharges in wild-type control zebrafish. Taken together, our results failed to replicate clear anti-seizure efficacy for these drug candidates highlighting a necessity for strict scientific standards in preclinical identification of anti-seizure medications.
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Affiliation(s)
- Paige A Whyte-Fagundes
- Epilepsy Research Laboratory and Weill Institute for Neuroscience, Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Anjelica Vance
- Epilepsy Research Laboratory and Weill Institute for Neuroscience, Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Aloe Carroll
- Behavioral Neurosciences, Northeastern University, Boston, MA 02115, USA
| | - Francisco Figueroa
- Epilepsy Research Laboratory and Weill Institute for Neuroscience, Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Catherine Manukyan
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720, USA
| | - Scott C Baraban
- Epilepsy Research Laboratory and Weill Institute for Neuroscience, Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720, USA
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3
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Lersch R, Jannadi R, Grosse L, Wagner M, Schneider MF, von Stülpnagel C, Heinen F, Potschka H, Borggraefe I. Targeted Molecular Strategies for Genetic Neurodevelopmental Disorders: Emerging Lessons from Dravet Syndrome. Neuroscientist 2023; 29:732-750. [PMID: 35414300 PMCID: PMC10623613 DOI: 10.1177/10738584221088244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Dravet syndrome is a severe developmental and epileptic encephalopathy mostly caused by heterozygous mutation of the SCN1A gene encoding the voltage-gated sodium channel α subunit Nav1.1. Multiple seizure types, cognitive deterioration, behavioral disturbances, ataxia, and sudden unexpected death associated with epilepsy are a hallmark of the disease. Recently approved antiseizure medications such as fenfluramine and cannabidiol have been shown to reduce seizure burden. However, patients with Dravet syndrome are still medically refractory in the majority of cases, and there is a high demand for new therapies aiming to improve behavioral and cognitive outcome. Drug-repurposing approaches for SCN1A-related Dravet syndrome are currently under investigation (i.e., lorcaserin, clemizole, and ataluren). New therapeutic concepts also arise from the field of precision medicine by upregulating functional SCN1A or by activating Nav1.1. These include antisense nucleotides directed against the nonproductive transcript of SCN1A with the poison exon 20N and against an inhibitory noncoding antisense RNA of SCN1A. Gene therapy approaches such as adeno-associated virus-based upregulation of SCN1A using a transcriptional activator (ETX101) or CRISPR/dCas technologies show promising results in preclinical studies. Although these new treatment concepts still need further clinical research, they offer great potential for precise and disease modifying treatment of Dravet syndrome.
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Affiliation(s)
- Robert Lersch
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
| | - Rawan Jannadi
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
- Institute of Human Genetics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
| | - Leonie Grosse
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
| | - Matias Wagner
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Institute for Neurogenomics, Helmholtz Centre Munich, German Research Center for Health and Environment (GmbH), Munich, Germany
| | - Marius Frederik Schneider
- Metabolic Biochemistry, Biomedical Center Munich, Medical Faculty, Ludwig Maximilians University, Munich, Germany
- International Max Planck Research School (IMPRS) for Molecular Life Sciences, Planegg-Martinsried, Germany
| | - Celina von Stülpnagel
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
- Research Institute for Rehabilitation, Transition and Palliation, Paracelsus Medical Private University (PMU), Salzburg, Austria
| | - Florian Heinen
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilians University, Munich, Germany
| | - Ingo Borggraefe
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
- Comprehensive Epilepsy Center, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
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4
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Whyte-Fagundes P, Vance A, Carroll A, Figueroa F, Manukyan C, Baraban SC. Testing of putative antiseizure drugs in a preclinical Dravet syndrome zebrafish model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.11.566723. [PMID: 38014342 PMCID: PMC10680609 DOI: 10.1101/2023.11.11.566723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Dravet syndrome (DS) is a severe genetic epilepsy primarily caused by de novo mutations in a voltage-activated sodium channel gene (SCN1A). Patients face life-threatening seizures that are largely resistant to available anti-seizure medications (ASM). Preclinical DS animal models are a valuable tool to identify candidate ASMs for these patients. Among these, scn1lab mutant zebrafish exhibiting spontaneous seizure-like activity are particularly amenable to large-scale drug screening. Prior screening in a scn1lab mutant zebrafish line generated using N-ethyl-Nnitrosourea (ENU) identified valproate, stiripentol, and fenfluramine e.g., Federal Drug Administration (FDA) approved drugs with clinical application in the DS population. Successful phenotypic screening in scn1lab mutant zebrafish consists of two stages: (i) a locomotion-based assay measuring high-velocity convulsive swim behavior and (ii) an electrophysiology-based assay, using in vivo local field potential (LFP) recordings, to quantify electrographic seizure-like events. Using this strategy more than 3000 drug candidates have been screened in scn1lab zebrafish mutants. Here, we curated a list of nine additional anti-seizure drug candidates recently identified in preclinical models: 1-EBIO, AA43279, chlorzoxazone, donepezil, lisuride, mifepristone, pargyline, soticlestat and vorinostat. First-stage locomotion-based assays in scn1lab mutant zebrafish identified only 1-EBIO, chlorzoxazone and lisuride. However, second-stage LFP recording assays did not show significant suppression of spontaneous electrographic seizure activity for any of the nine anti-seizure drug candidates. Surprisingly, soticlestat induced frank electrographic seizure-like discharges in wild-type control zebrafish. Taken together, our results failed to replicate clear anti-seizure efficacy for these drug candidates highlighting a necessity for strict scientific standards in preclinical identification of ASMs.
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Affiliation(s)
- P Whyte-Fagundes
- Epilepsy Research Laboratory and Weill Institute for Neuroscience, Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA
| | - A Vance
- Epilepsy Research Laboratory and Weill Institute for Neuroscience, Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA
| | - A Carroll
- Behavioral Neurosciences, Northeastern University, Boston, MA, USA
| | - F Figueroa
- Epilepsy Research Laboratory and Weill Institute for Neuroscience, Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA
| | - C Manukyan
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - S C Baraban
- Epilepsy Research Laboratory and Weill Institute for Neuroscience, Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
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5
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Riva A, D'Onofrio G, Amadori E, Tripodi D, Balagura G, Iurilli V, Vari MS, Verrotti A, Striano P. Current and promising therapeutic options for Dravet syndrome. Expert Opin Pharmacother 2022; 23:1727-1736. [PMID: 36124778 DOI: 10.1080/14656566.2022.2127089] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Dravet Syndrome (DS) is a developmental and epileptic encephalopathy carrying high-level psychobehavioral burdens. Although the disease has been known for almost 4 decades, and despite significant progress in the understanding of its physiopathology and natural course, the pharmacological treatment leaves patients and caregivers with significant unmet needs. This review provides a summary of the current and promising therapeutic options for DS. AREAS COVERED PubMed and ClinicalTrials.gov were screened using 'Dravet Syndrome' OR 'DS,' AND 'pharmacotherapy,' AND 'treatments.' Randomized clinical trials, structured reviews, and meta-analyses were selected for in-human application of well-known anti-seizure medications; while in-vivo experiments on models of DS were selected to evaluate the potential of new therapeutic strategies. EXPERT OPINION The search for new pharmacological treatment options is led by the need for care and defeat of the natural course of the disease, an aspect still largely neglected by the available therapeutic strategies. Yet, the last 6 years have led to a climate of increased interest and availability of clinical trials. Particularly, gene therapy could hopefully prevent DS evolution by directly relieving the specific genetic defect, although the possibility of off-target editing, and the uneasy administration route have still largely prevented its use.
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Affiliation(s)
- Antonella Riva
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Gianluca D'Onofrio
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Elisabetta Amadori
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Domenico Tripodi
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti, Genoa, Italy
| | - Ganna Balagura
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU), de Boelelaan, Amsterdam, Netherlands
| | | | - Maria Stella Vari
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | | | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
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6
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Specchio N, Pietrafusa N, Perucca E, Cross JH. New paradigms for the treatment of pediatric monogenic epilepsies: Progressing toward precision medicine. Epilepsy Behav 2022; 131:107961. [PMID: 33867301 DOI: 10.1016/j.yebeh.2021.107961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/25/2022]
Abstract
Despite the availability of 28 antiseizure medications (ASMs), one-third of people with epilepsy fail to achieve sustained freedom from seizures. Clinical outcome is even poorer for children with developmental and epileptic encephalopathies (DEEs), many of which are due to single-gene mutations. Discovery of causative genes, however, has paved the way to understanding the molecular mechanism underlying these epilepsies, and to the rational application, or development, of precision treatments aimed at correcting the specific functional defects or their consequences. This article provides an overview of current progress toward precision medicine (PM) in the management of monogenic pediatric epilepsies, by focusing on four different scenarios, namely (a) rational selection of ASMs targeting specifically the underlying pathogenetic mechanisms; (b) development of targeted therapies based on novel molecules; (c) use of dietary treatments or food constituents aimed at correcting specific metabolic defects; and (d) repurposing of medications originally approved for other indications. This article is part of the Special Issue "Severe Infantile Epilepsies".
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Affiliation(s)
- Nicola Specchio
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy.
| | - Nicola Pietrafusa
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Emilio Perucca
- Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy
| | - J Helen Cross
- UCL NIHR BRC Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children, London, UK
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Chronic partial TrkB activation reduces seizures and mortality in a mouse model of Dravet syndrome. Proc Natl Acad Sci U S A 2022; 119:2022726119. [PMID: 35165147 PMCID: PMC8851461 DOI: 10.1073/pnas.2022726119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2021] [Indexed: 12/03/2022] Open
Abstract
Dravet syndrome (DS) is a severe childhood epileptic encephalopathy characterized by intractable seizures and comorbidities, including a high rate of premature mortality. DS is mainly caused by loss-of-function mutations of the Scn1a gene encoding sodium channel Nav1.1 that is predominantly expressed in inhibitory parvalbumin-containing (PV) interneurons. Decreased Nav1.1 impairs PV cell function, causing DS phenotypes. Effective pharmacological therapy targeting defective PV interneurons is currently not available. This study demonstrated that early treatment with a partial TrkB receptor agonist, LM22A-4, increased Nav1.1 expression, improved PV interneuron function, and reduced seizure occurrence and mortality rate in DS mice, suggesting a potential therapy for DS. Dravet syndrome (DS) is one of the most severe childhood epilepsies, characterized by intractable seizures and comorbidities including cognitive and social dysfunction and high premature mortality. DS is mainly caused by loss-of-function mutations in the Scn1a gene encoding Nav1.1 that is predominantly expressed in inhibitory parvalbumin-containing (PV) interneurons. Decreased Nav1.1 impairs PV cell function, contributing to DS phenotypes. Effective pharmacological therapy that targets defective PV interneurons is not available. The known role of brain-derived neurotrophic factor (BDNF) in the development and maintenance of interneurons, together with our previous results showing improved PV interneuronal function and antiepileptogenic effects of a TrkB receptor agonist in a posttraumatic epilepsy model, led to the hypothesis that early treatment with a TrkB receptor agonist might prevent or reduce seizure activity in DS mice. To test this hypothesis, we treated DS mice with LM22A-4 (LM), a partial agonist at the BDNF TrkB receptor, for 7 d starting at postnatal day 13 (P13), before the onset of spontaneous seizures. Results from immunohistochemistry, Western blot, whole-cell patch-clamp recording, and in vivo seizure monitoring showed that LM treatment increased the number of perisomatic PV interneuronal synapses around cortical pyramidal cells in layer V, upregulated Nav1.1 in PV neurons, increased inhibitory synaptic transmission, and decreased seizures and the mortality rate in DS mice. The results suggest that early treatment with a partial TrkB receptor agonist may be a promising therapeutic approach to enhance PV interneuron function and reduce epileptogenesis and premature death in DS.
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Cardenal-Muñoz E, Auvin S, Villanueva V, Cross JH, Zuberi SM, Lagae L, Aibar JÁ. Guidance on Dravet syndrome from infant to adult care: Road map for treatment planning in Europe. Epilepsia Open 2021; 7:11-26. [PMID: 34882995 PMCID: PMC8886070 DOI: 10.1002/epi4.12569] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/24/2021] [Accepted: 12/02/2021] [Indexed: 12/22/2022] Open
Abstract
Dravet syndrome (DS) is a severe, rare, and complex developmental and epileptic encephalopathy affecting 1 in 16 000 live births and characterized by a drug‐resistant epilepsy, cognitive, psychomotor, and language impairment, and behavioral disorders. Evidence suggests that optimal treatment of seizures in DS may improve outcomes, even though neurodevelopmental impairments are the likely result of both the underlying genetic variant and the epilepsy. We present an updated guideline for DS diagnosis and treatment, taking into consideration care of the adult patient and nonpharmaceutical therapeutic options for this disease. This up‐to‐date guideline, which is based on an extensive review of the literature and culminates with a new treatment algorithm for DS, is a European consensus developed through a survey involving 29 European clinical experts in DS. This guideline will serve professionals in their clinical practice and, as a consequence, will benefit DS patients and their families.
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Affiliation(s)
- Elena Cardenal-Muñoz
- Dravet Syndrome Foundation Spain, Member of the EpiCARE ePAG Group, Madrid, Spain
| | - Stéphane Auvin
- APHP. Service de Neurologie Pédiatrique, Hôpital Robert Debré, Paris, France.,INSERM NeuroDiderot, Université de Paris, Paris, France.,Institut Universitaire de France (IUF), Paris, France
| | - Vicente Villanueva
- Refractory Epilepsy Unit, Hospital Universitario y Politécnico La Fe, Member of the ERN EpiCARE, Valencia, Spain
| | - J Helen Cross
- Department of Developmental Neurosciences, UCL NIHR BRC Great Ormond Street Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital for Children, Member of the ERN EpiCARE, London, UK
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Member of the ERN EpiCARE, Glasgow, UK.,Institute of Health & Wellbeing, University of Glasgow, Glasgow, UK
| | - Lieven Lagae
- Department of Development and Regeneration, KU Leuven, Member of the ERN EpiCARE, Leuven, Belgium
| | - José Ángel Aibar
- Dravet Syndrome Foundation Spain, Member of the EpiCARE ePAG Group, Madrid, Spain
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Nicole S, Lory P. New Challenges Resulting From the Loss of Function of Na v1.4 in Neuromuscular Diseases. Front Pharmacol 2021; 12:751095. [PMID: 34671263 PMCID: PMC8521073 DOI: 10.3389/fphar.2021.751095] [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: 07/31/2021] [Accepted: 09/16/2021] [Indexed: 11/13/2022] Open
Abstract
The voltage-gated sodium channel Nav1.4 is a major actor in the excitability of skeletal myofibers, driving the muscle force in response to nerve stimulation. Supporting further this key role, mutations in SCN4A, the gene encoding the pore-forming α subunit of Nav1.4, are responsible for a clinical spectrum of human diseases ranging from muscle stiffness (sodium channel myotonia, SCM) to muscle weakness. For years, only dominantly-inherited diseases resulting from Nav1.4 gain of function (GoF) were known, i.e., non-dystrophic myotonia (delayed muscle relaxation due to myofiber hyperexcitability), paramyotonia congenita and hyperkalemic or hypokalemic periodic paralyses (episodic flaccid muscle weakness due to transient myofiber hypoexcitability). These last 5 years, SCN4A mutations inducing Nav1.4 loss of function (LoF) were identified as the cause of dominantly and recessively-inherited disorders with muscle weakness: periodic paralyses with hypokalemic attacks, congenital myasthenic syndromes and congenital myopathies. We propose to name this clinical spectrum sodium channel weakness (SCW) as the mirror of SCM. Nav1.4 LoF as a cause of permanent muscle weakness was quite unexpected as the Na+ current density in the sarcolemma is large, securing the ability to generate and propagate muscle action potentials. The properties of SCN4A LoF mutations are well documented at the channel level in cellular electrophysiological studies However, much less is known about the functional consequences of Nav1.4 LoF in skeletal myofibers with no available pertinent cell or animal models. Regarding the therapeutic issues for Nav1.4 channelopathies, former efforts were aimed at developing subtype-selective Nav channel antagonists to block myofiber hyperexcitability. Non-selective, Nav channel blockers are clinically efficient in SCM and paramyotonia congenita, whereas patient education and carbonic anhydrase inhibitors are helpful to prevent attacks in periodic paralyses. Developing therapeutic tools able to counteract Nav1.4 LoF in skeletal muscles is then a new challenge in the field of Nav channelopathies. Here, we review the current knowledge regarding Nav1.4 LoF and discuss the possible therapeutic strategies to be developed in order to improve muscle force in SCW.
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Affiliation(s)
- Sophie Nicole
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics (ICST), Montpellier, France
| | - Philippe Lory
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics (ICST), Montpellier, France
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10
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New avenues in molecular genetics for the diagnosis and application of therapeutics to the epilepsies. Epilepsy Behav 2021; 121:106428. [PMID: 31400936 DOI: 10.1016/j.yebeh.2019.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 06/14/2019] [Accepted: 07/06/2019] [Indexed: 11/22/2022]
Abstract
Genetic epidemiology studies have shown that most epilepsies involve some genetic cause. In addition, twin studies have helped strengthen the hypothesis that in most patients with epilepsy, a complex inheritance is involved. More recently, with the development of high-density single-nucleotide polymorphism (SNP) microarrays and next-generation sequencing (NGS) technologies, the discovery of genes related to the epilepsies has accelerated tremendously. Especially, the use of whole exome sequencing (WES) has had a considerable impact on the identification of rare genetic variants with large effect sizes, including inherited or de novo mutations in severe forms of childhood epilepsies. The identification of pathogenic variants in patients with these childhood epilepsies provides many benefits for patients and families, such as the confirmation of the genetic nature of the diseases. This process will allow for better genetic counseling, more accurate therapy decisions, and a significant positive emotional impact. However, to study the genetic component of the more common forms of epilepsy, the use of high-density SNP arrays in genome-wide association studies (GWAS) seems to be the strategy of choice. As such, researchers can identify loci containing genetic variants associated with the common forms of epilepsy. The knowledge generated over the past two decades about the effects of the mutations that cause the monogenic epilepsy is tremendous; however, the scientific community is just starting to apply this information in order to generate better target treatments.
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11
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Zhang Y, Wang K, Yu Z. Drug Development in Channelopathies: Allosteric Modulation of Ligand-Gated and Voltage-Gated Ion Channels. J Med Chem 2020; 63:15258-15278. [PMID: 33253554 DOI: 10.1021/acs.jmedchem.0c01304] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ion channels have been characterized as promising drug targets for treatment of numerous human diseases. Functions of ion channels can be fine-tuned by allosteric modulators, which interact with channels and modulate their activities by binding to sites spatially discrete from those of orthosteric ligands. Positive and negative allosteric modulators have presented a plethora of potential therapeutic advantages over traditionally orthosteric agonists and antagonists in terms of selectivity and safety. This thematic review highlights the discovery of representative allosteric modulators for ligand-gated and voltage-gated ion channels, discussing in particular their identifications, locations, and therapeutic uses in the treatment of a range of channelopathies. Additionally, structures and functions of selected ion channels are briefly described to aid in the rational design of channel modulators. Overall, allosteric modulation represents an innovative targeting approach, and the corresponding modulators provide an abundant but challenging landscape for novel therapeutics targeting ligand-gated and voltage-gated ion channels.
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Affiliation(s)
- Yanyun Zhang
- Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Ke Wang
- Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Zhiyi Yu
- Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
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12
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Löscher W, Potschka H, Sisodiya SM, Vezzani A. Drug Resistance in Epilepsy: Clinical Impact, Potential Mechanisms, and New Innovative Treatment Options. Pharmacol Rev 2020; 72:606-638. [PMID: 32540959 PMCID: PMC7300324 DOI: 10.1124/pr.120.019539] [Citation(s) in RCA: 355] [Impact Index Per Article: 88.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Epilepsy is a chronic neurologic disorder that affects over 70 million people worldwide. Despite the availability of over 20 antiseizure drugs (ASDs) for symptomatic treatment of epileptic seizures, about one-third of patients with epilepsy have seizures refractory to pharmacotherapy. Patients with such drug-resistant epilepsy (DRE) have increased risks of premature death, injuries, psychosocial dysfunction, and a reduced quality of life, so development of more effective therapies is an urgent clinical need. However, the various types of epilepsy and seizures and the complex temporal patterns of refractoriness complicate the issue. Furthermore, the underlying mechanisms of DRE are not fully understood, though recent work has begun to shape our understanding more clearly. Experimental models of DRE offer opportunities to discover, characterize, and challenge putative mechanisms of drug resistance. Furthermore, such preclinical models are important in developing therapies that may overcome drug resistance. Here, we will review the current understanding of the molecular, genetic, and structural mechanisms of ASD resistance and discuss how to overcome this problem. Encouragingly, better elucidation of the pathophysiological mechanisms underpinning epilepsies and drug resistance by concerted preclinical and clinical efforts have recently enabled a revised approach to the development of more promising therapies, including numerous potential etiology-specific drugs (“precision medicine”) for severe pediatric (monogenetic) epilepsies and novel multitargeted ASDs for acquired partial epilepsies, suggesting that the long hoped-for breakthrough in therapy for as-yet ASD-resistant patients is a feasible goal.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany (W.L.); Center for Systems Neuroscience, Hannover, Germany (W.L.); Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany (H.P.); Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom (S.S); and Department of Neuroscience, Mario Negri Institute for Pharmacological Research Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy (A.V.)
| | - Heidrun Potschka
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany (W.L.); Center for Systems Neuroscience, Hannover, Germany (W.L.); Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany (H.P.); Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom (S.S); and Department of Neuroscience, Mario Negri Institute for Pharmacological Research Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy (A.V.)
| | - Sanjay M Sisodiya
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany (W.L.); Center for Systems Neuroscience, Hannover, Germany (W.L.); Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany (H.P.); Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom (S.S); and Department of Neuroscience, Mario Negri Institute for Pharmacological Research Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy (A.V.)
| | - Annamaria Vezzani
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany (W.L.); Center for Systems Neuroscience, Hannover, Germany (W.L.); Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany (H.P.); Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom (S.S); and Department of Neuroscience, Mario Negri Institute for Pharmacological Research Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy (A.V.)
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Weuring WJ, Singh S, Volkers L, Rook MB, van ‘t Slot RH, Bosma M, Inserra M, Vetter I, Verhoeven-Duif NM, Braun KPJ, Rivara M, Koeleman BPC. NaV1.1 and NaV1.6 selective compounds reduce the behavior phenotype and epileptiform activity in a novel zebrafish model for Dravet Syndrome. PLoS One 2020; 15:e0219106. [PMID: 32134913 PMCID: PMC7058281 DOI: 10.1371/journal.pone.0219106] [Citation(s) in RCA: 20] [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: 07/08/2019] [Accepted: 02/04/2020] [Indexed: 12/03/2022] Open
Abstract
Dravet syndrome is caused by dominant loss-of-function mutations in SCN1A which cause reduced activity of Nav1.1 leading to lack of neuronal inhibition. On the other hand, gain-of-function mutations in SCN8A can lead to a severe epileptic encephalopathy subtype by over activating NaV1.6 channels. These observations suggest that Nav1.1 and Nav1.6 represent two opposing sides of the neuronal balance between inhibition and activation. Here, we hypothesize that Dravet syndrome may be treated by either enhancing Nav1.1 or reducing Nav1.6 activity. To test this hypothesis we generated and characterized a novel DS zebrafish model and tested new compounds that selectively activate or inhibit the human NaV1.1 or NaV1.6 channel respectively. We used CRISPR/Cas9 to generate two separate Scn1Lab knockout lines as an alternative to previous zebrafish models generated by random mutagenesis or morpholino oligomers. Using an optimized locomotor assay, spontaneous burst movements were detected that were unique to Scn1Lab knockouts and disappear when introducing human SCN1A mRNA. Besides the behavioral phenotype, Scn1Lab knockouts show sudden, electrical discharges in the brain that indicate epileptic seizures in zebrafish. Scn1Lab knockouts showed increased sensitivity to the GABA antagonist pentylenetetrazole and a reduction in whole organism GABA levels. Drug screenings further validated a Dravet syndrome phenotype. We tested the NaV1.1 activator AA43279 and two novel NaV1.6 inhibitors MV1369 and MV1312 in the Scn1Lab knockouts. Both type of compounds significantly reduced the number of spontaneous burst movements and seizure activity. Our results show that selective inhibition of NaV1.6 could be just as efficient as selective activation of NaV1.1 and these approaches could prove to be novel potential treatment strategies for Dravet syndrome and other (genetic) epilepsies. Compounds tested in zebrafish however, should always be further validated in other model systems for efficacy in mammals and to screen for potential side effects.
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Affiliation(s)
- Wout J. Weuring
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Sakshi Singh
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Linda Volkers
- Department of Cardiology, Laboratory of Experimental Cardiology, University Medical Centre Leiden, Leiden, the Netherlands
| | - Martin B. Rook
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Ruben H. van ‘t Slot
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Marjolein Bosma
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Marco Inserra
- Centre for Pain Research & School of Pharmacy, University of Queensland, Brisbane, Australia
| | - Irina Vetter
- Centre for Pain Research & School of Pharmacy, University of Queensland, Brisbane, Australia
| | - Nanda M. Verhoeven-Duif
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Kees P. J. Braun
- Department of Neurology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Mirko Rivara
- Food and Drug Department, University of Parma, Parma, Italy
| | - Bobby P. C. Koeleman
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
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Nakazawa K, Sapkota K. The origin of NMDA receptor hypofunction in schizophrenia. Pharmacol Ther 2019; 205:107426. [PMID: 31629007 DOI: 10.1016/j.pharmthera.2019.107426] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/10/2019] [Indexed: 12/12/2022]
Abstract
N-methyl-d-aspartate (NMDA) receptor (NMDAR) hypofunction plays a key role in pathophysiology of schizophrenia. Since NMDAR hypofunction has also been reported in autism, Alzheimer's disease and cognitive dementia, it is crucial to identify the location, timing, and mechanism of NMDAR hypofunction for schizophrenia for better understanding of disease etiology and for novel therapeutic intervention. In this review, we first discuss the shared underlying mechanisms of NMDAR hypofunction in NMDAR antagonist models and the anti-NMDAR autoantibody model of schizophrenia and suggest that NMDAR hypofunction could occur in GABAergic neurons in both models. Preclinical models using transgenic mice have shown that NMDAR hypofunction in cortical GABAergic neurons, in particular parvalbumin-positive fast-spiking interneurons, in the early postnatal period confers schizophrenia-related phenotypes. Recent studies suggest that NMDAR hypofunction can also occur in PV-positive GABAergic neurons with alterations of NMDAR-associated proteins, such as neuregulin/ErbB4, α7nAChR, and serine racemase. Furthermore, several environmental factors, such as oxidative stress, kynurenic acid and hypoxia, may also potentially elicit NMDAR hypofunction in GABAergic neurons in early postnatal period. Altogether, the studies discussed here support a central role for GABAergic abnormalities in the context of NMDAR hypofunction. We conclude by suggesting potential therapeutic strategies to improve the function of fast-spiking neurons.
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Miyazaki T, Kawasaki M, Suzuki A, Ito Y, Imanishi A, Maru T, Kawamoto T, Koike T. Discovery of novel 4-phenyl-2-(pyrrolidinyl)nicotinamide derivatives as potent Na v1.1 activators. Bioorg Med Chem Lett 2019; 29:815-820. [PMID: 30704812 DOI: 10.1016/j.bmcl.2019.01.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 11/25/2022]
Abstract
The voltage-gated sodium channel, Nav1.1, is predominantly expressed in parvalbumin-positive fast spiking interneurons and has been genetically linked to Dravet syndrome. Starting from a high throughput screening hit isoxazole derivative 5, modifications of 5 via combinations of IonWorks and Q-patch assays successfully identified the nicotinamide derivative 4. Its increasing decay time constant (tau) of Nav1.1 currents at 0.03 μM along with significant selectivity against Nav1.2, Nav1.5, and Nav1.6 and acceptable brain exposure in mice was observed. Compound 4 is a promising Nav1.1 activator that can be used to analyze pathophysiological functions of the Nav1.1 channel towards treating various central nervous system diseases.
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Affiliation(s)
- Tohru Miyazaki
- Research, Takeda Pharmaceutical Company Ltd., Fujisawa, Kanagawa 251-8555, Japan.
| | - Masanori Kawasaki
- Research, Takeda Pharmaceutical Company Ltd., Fujisawa, Kanagawa 251-8555, Japan
| | - Atsushi Suzuki
- Research, Takeda Pharmaceutical Company Ltd., Fujisawa, Kanagawa 251-8555, Japan
| | - Yuki Ito
- Research, Takeda Pharmaceutical Company Ltd., Fujisawa, Kanagawa 251-8555, Japan
| | - Akio Imanishi
- Research, Takeda Pharmaceutical Company Ltd., Fujisawa, Kanagawa 251-8555, Japan
| | - Takamitsu Maru
- Axcelead Drug Discovery Partners, Inc., Fujisawa, Kanagawa 251-0012, Japan
| | - Tomohiro Kawamoto
- Axcelead Drug Discovery Partners, Inc., Fujisawa, Kanagawa 251-0012, Japan
| | - Tatsuki Koike
- Research, Takeda Pharmaceutical Company Ltd., Fujisawa, Kanagawa 251-8555, Japan
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16
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Novel Quantitative Analyses of Spontaneous Synaptic Events in Cortical Pyramidal Cells Reveal Subtle Parvalbumin-Expressing Interneuron Dysfunction in a Knock-In Mouse Model of Alzheimer's Disease. eNeuro 2018; 5:eN-CFN-0059-18. [PMID: 30105300 PMCID: PMC6088364 DOI: 10.1523/eneuro.0059-18.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/19/2018] [Accepted: 06/24/2018] [Indexed: 12/19/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder that has become a compelling global public health concern. Besides pathological hallmarks such as extracellular amyloid plaques, intracellular neurofibrillary tangles (NFTs), and loss of neurons and synapses, clinical reports have shown that epileptiform activity, even seizures, can occur early in the disease. Aberrant synaptic and network activities as well as epileptiform discharges have also been observed in various mouse models of AD. The new AppNL-F mouse model is generated by a gene knock-in approach and there are limited studies on basic synaptic properties in AppNL-F mice. Therefore, we applied quantitative methods to analyze spontaneous excitatory and inhibitory synaptic events in parietal cortex layer 2/3 pyramidal cells. First, by an objective amplitude distribution analysis, we found decreased amplitudes of spontaneous IPSCs (sIPSCs) in aged AppNL-F mice caused by a reduction in the amplitudes of the large sIPSCs with fast rates of rise, consistent with deficits in the function of parvalbumin-expressing interneurons (PV INs). Second, we calculated the burstiness and memory in a series of successive synaptic events. Lastly, by using a novel approach to determine the excitation-to-inhibition (E/I) ratio, we found no changes in the AppNL-F mice, indicating that homeostatic mechanisms may have maintained the overall balance of excitation and inhibition in spite of a mildly impaired PV IN function.
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A Transient Developmental Window of Fast-Spiking Interneuron Dysfunction in a Mouse Model of Dravet Syndrome. J Neurosci 2018; 38:7912-7927. [PMID: 30104343 DOI: 10.1523/jneurosci.0193-18.2018] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 07/12/2018] [Accepted: 07/17/2018] [Indexed: 01/06/2023] Open
Abstract
Dravet syndrome is a severe, childhood-onset epilepsy largely due to heterozygous loss-of-function mutation of the gene SCN1A, which encodes the type 1 neuronal voltage-gated sodium (Na+) channel α subunit Nav1.1. Prior studies in mouse models of Dravet syndrome (Scn1a+/- mice) indicate that, in cerebral cortex, Nav1.1 is predominantly expressed in GABAergic interneurons, in particular in parvalbumin-positive fast-spiking basket cell interneurons (PVINs). This has led to a model of Dravet syndrome pathogenesis in which Nav1.1 mutation leads to preferential dysfunction of interneurons, decreased synaptic inhibition, hyperexcitability, and epilepsy. However, such studies have been implemented at early developmental time points. Here, we performed electrophysiological recordings in acute brain slices prepared from male and female Scn1a+/- mice as well as age-matched wild-type littermate controls and found that, later in development, the excitability of PVINs had normalized. Analysis of action potential waveforms indirectly suggests a reorganization of axonal Na+ channels in PVINs from Scn1a+/- mice, a finding supported by immunohistochemical data showing elongation of the axon initial segment. Our results imply that transient impairment of action potential generation by PVINs may contribute to the initial appearance of epilepsy, but is not the mechanism of ongoing, chronic epilepsy in Dravet syndrome.SIGNIFICANCE STATEMENT Dravet syndrome is characterized by normal early development, temperature-sensitive seizures in infancy, progression to treatment-resistant epilepsy, developmental delay, autism, and sudden unexplained death due to mutation in SCN1A encoding the Na+ channel subunit Nav1.1. Prior work has revealed a preferential impact of Nav1.1 loss on the function of GABAergic inhibitory interneurons. However, such data derive exclusively from recordings of neurons in young Scn1a+/- mice. Here, we show that impaired action potential generation observed in parvalbumin-positive fast-spiking interneurons (PVINs) in Scn1a+/- mice during early development has normalized by postnatal day 35. This work suggests that a transient impairment of PVINs contributes to epilepsy onset, but is not the mechanism of ongoing, chronic epilepsy in Dravet syndrome.
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18
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Sanders SJ, Campbell AJ, Cottrell JR, Moller RS, Wagner FF, Auldridge AL, Bernier RA, Catterall WA, Chung WK, Empfield JR, George AL, Hipp JF, Khwaja O, Kiskinis E, Lal D, Malhotra D, Millichap JJ, Otis TS, Petrou S, Pitt G, Schust LF, Taylor CM, Tjernagel J, Spiro JE, Bender KJ. Progress in Understanding and Treating SCN2A-Mediated Disorders. Trends Neurosci 2018; 41:442-456. [PMID: 29691040 DOI: 10.1016/j.tins.2018.03.011] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 03/09/2018] [Accepted: 03/14/2018] [Indexed: 01/20/2023]
Abstract
Advances in gene discovery for neurodevelopmental disorders have identified SCN2A dysfunction as a leading cause of infantile seizures, autism spectrum disorder, and intellectual disability. SCN2A encodes the neuronal sodium channel NaV1.2. Functional assays demonstrate strong correlation between genotype and phenotype. This insight can help guide therapeutic decisions and raises the possibility that ligands that selectively enhance or diminish channel function may improve symptoms. The well-defined function of sodium channels makes SCN2A an important test case for investigating the neurobiology of neurodevelopmental disorders more generally. Here, we discuss the progress made, through the concerted efforts of a diverse group of academic and industry scientists as well as policy advocates, in understanding and treating SCN2A-related disorders.
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Affiliation(s)
- Stephan J Sanders
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Arthur J Campbell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, MA 02142, USA
| | - Jeffrey R Cottrell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, MA 02142, USA
| | - Rikke S Moller
- The Danish Epilepsy Centre, Dianalund, Denmark; Institute for Regional Health Services, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Florence F Wagner
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, MA 02142, USA
| | - Angie L Auldridge
- FamilieSCN2a Foundation, P.O. Box 82, East Longmeadow, MA 01028, USA
| | - Raphael A Bernier
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Wendy K Chung
- Simons Foundation, New York, NY 10010, USA; Department of Pediatrics and Medicine, Columbia University, New York, NY 10032, USA
| | - James R Empfield
- Xenon Pharmaceuticals Inc., 3650 Gilmore Way, Burnaby, BC V5G 4W8, Canada
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Joerg F Hipp
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Omar Khwaja
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Evangelos Kiskinis
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA; Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Dennis Lal
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, MA 02142, USA
| | - Dheeraj Malhotra
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - John J Millichap
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA; Epilepsy Center and Division of Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, IL 60611, USA; Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Thomas S Otis
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, 25 Howland Street, London W1T 4JG, UK
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Geoffrey Pitt
- Cardiovascular Research Institute, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
| | - Leah F Schust
- FamilieSCN2a Foundation, P.O. Box 82, East Longmeadow, MA 01028, USA
| | - Cora M Taylor
- Geisinger Health System, 100 North Academy Avenue, Danville, PA 17822, USA
| | | | | | - Kevin J Bender
- Department of Neurology, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA.
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Carpenter JC, Schorge S. The voltage-gated channelopathies as a paradigm for studying epilepsy-causing genes. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Oyrer J, Maljevic S, Scheffer IE, Berkovic SF, Petrou S, Reid CA. Ion Channels in Genetic Epilepsy: From Genes and Mechanisms to Disease-Targeted Therapies. Pharmacol Rev 2018; 70:142-173. [PMID: 29263209 DOI: 10.1124/pr.117.014456] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy is a common and serious neurologic disease with a strong genetic component. Genetic studies have identified an increasing collection of disease-causing genes. The impact of these genetic discoveries is wide reaching-from precise diagnosis and classification of syndromes to the discovery and validation of new drug targets and the development of disease-targeted therapeutic strategies. About 25% of genes identified in epilepsy encode ion channels. Much of our understanding of disease mechanisms comes from work focused on this class of protein. In this study, we review the genetic, molecular, and physiologic evidence supporting the pathogenic role of a number of different voltage- and ligand-activated ion channels in genetic epilepsy. We also review proposed disease mechanisms for each ion channel and highlight targeted therapeutic strategies.
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Affiliation(s)
- Julia Oyrer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Ingrid E Scheffer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Samuel F Berkovic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
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21
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von Schoubye NL, Frederiksen K, Kristiansen U, Petersen AV, Dalby NO, Grunnet M, Jensen HS, Jespersen T, Sohal VS, Perrier JF. The sodium channel activator Lu AE98134 normalizes the altered firing properties of fast spiking interneurons in Dlx5/6+/− mice. Neurosci Lett 2018; 662:29-35. [DOI: 10.1016/j.neulet.2017.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/22/2017] [Accepted: 10/03/2017] [Indexed: 11/25/2022]
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