1
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Shore AN, Li K, Safari M, Qunies AM, Spitznagel BD, Weaver CD, Emmitte K, Frankel W, Weston MC. Heterozygous expression of a Kcnt1 gain-of-function variant has differential effects on somatostatin- and parvalbumin-expressing cortical GABAergic neurons. eLife 2024; 13:RP92915. [PMID: 39392867 PMCID: PMC11469685 DOI: 10.7554/elife.92915] [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] [Indexed: 10/13/2024] Open
Abstract
More than 20 recurrent missense gain-of-function (GOF) mutations have been identified in the sodium-activated potassium (KNa) channel gene KCNT1 in patients with severe developmental and epileptic encephalopathies (DEEs), most of which are resistant to current therapies. Defining the neuron types most vulnerable to KCNT1 GOF will advance our understanding of disease mechanisms and provide refined targets for precision therapy efforts. Here, we assessed the effects of heterozygous expression of a Kcnt1 GOF variant (Kcnt1Y777H) on KNa currents and neuronal physiology among cortical glutamatergic and GABAergic neurons in mice, including those expressing vasoactive intestinal polypeptide (VIP), somatostatin (SST), and parvalbumin (PV), to identify and model the pathogenic mechanisms of autosomal dominant KCNT1 GOF variants in DEEs. Although the Kcnt1Y777H variant had no effects on glutamatergic or VIP neuron function, it increased subthreshold KNa currents in both SST and PV neurons but with opposite effects on neuronal output; SST neurons became hypoexcitable with a higher rheobase current and lower action potential (AP) firing frequency, whereas PV neurons became hyperexcitable with a lower rheobase current and higher AP firing frequency. Further neurophysiological and computational modeling experiments showed that the differential effects of the Kcnt1Y777H variant on SST and PV neurons are not likely due to inherent differences in these neuron types, but to an increased persistent sodium current in PV, but not SST, neurons. The Kcnt1Y777H variant also increased excitatory input onto, and chemical and electrical synaptic connectivity between, SST neurons. Together, these data suggest differential pathogenic mechanisms, both direct and compensatory, contribute to disease phenotypes, and provide a salient example of how a pathogenic ion channel variant can cause opposite functional effects in closely related neuron subtypes due to interactions with other ionic conductances.
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Affiliation(s)
- Amy N Shore
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology ResearchRoanokeUnited States
- Department of Neurological Sciences, University of VermontBurlingtonUnited States
| | - Keyong Li
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology ResearchRoanokeUnited States
| | - Mona Safari
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology ResearchRoanokeUnited States
- Translational Biology, Medicine, and Health Graduate Program, Fralin Biomedical Research Institute at Virginia Tech CarilionRoanokeUnited States
| | - Alshaima'a M Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science CenterFort WorthUnited States
- School of Biomedical Sciences, University of North Texas Health Science CenterFort WorthUnited States
| | - Brittany D Spitznagel
- Department of Pharmacology, Vanderbilt UniversityNashvilleUnited States
- Vanderbilt Institute of Chemical Biology, Vanderbilt UniversityNashvilleUnited States
- Department of Chemistry, Vanderbilt UniversityNashvilleUnited States
| | - C David Weaver
- Department of Pharmacology, Vanderbilt UniversityNashvilleUnited States
- Vanderbilt Institute of Chemical Biology, Vanderbilt UniversityNashvilleUnited States
- Department of Chemistry, Vanderbilt UniversityNashvilleUnited States
| | - Kyle Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science CenterFort WorthUnited States
| | - Wayne Frankel
- Institute for Genomic Medicine, Columbia UniversityNew YorkUnited States
- Department of Neurology, Columbia UniversityNew YorkUnited States
| | - Matthew C Weston
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology ResearchRoanokeUnited States
- Department of Neurological Sciences, University of VermontBurlingtonUnited States
- Translational Biology, Medicine, and Health Graduate Program, Fralin Biomedical Research Institute at Virginia Tech CarilionRoanokeUnited States
- School of Neuroscience, Virginia TechBlacksburgUnited States
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2
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Di C, Wu T, Gao K, Li N, Song H, Wang L, Sun H, Yi J, Zhang X, Chen J, Shah M, Jiang Y, Huang Z. Carvedilol inhibits neuronal hyperexcitability caused by epilepsy-associated KCNT1 mutations. Br J Pharmacol 2024. [PMID: 39370580 DOI: 10.1111/bph.17360] [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: 03/12/2024] [Revised: 08/27/2024] [Accepted: 09/03/2024] [Indexed: 10/08/2024] Open
Abstract
BACKGROUND AND PURPOSE KCNT1 encodes a sodium-activated potassium channel (Slack channel), and its mutation can cause several forms of epilepsy. Traditional antiepileptic medications have limited efficacy in treating patients with KCNT1 mutations. Here, we describe one heterozygous KCNT1 mutation, M267T, in a patient with EIMFS. The pathological channel properties of this mutation and its effect on neuronal excitability were investigated. Additionally, this study aimed to develop a medication for effective prevention of KCNT1 mutation-induced seizures. EXPERIMENTAL APPROACH Wild-type or mutant KCNT1 plasmids were expressed heterologously in Xenopus laevis oocytes, and channel property assessment and drug screening were performed based on two-electrode voltage-clamp recordings. The single-channel properties were investigated using the excised inside-out patches from HEK293T cells. Through in utero electroporation, WT and M267T Slack channels were expressed in the hippocampal CA1 pyramidal neurons in male mice, followed by the examination of the electrical properties using the whole-cell current-clamp technique. The kainic acid-induced epilepsy model in male mice was used to evalute the antiseizure effects of carvedilol. KEY RESULTS The KCNT1 M267T mutation enhanced Slack channel function by increasing single-channel open probability. Through screening 16 FDA-approved ion channel blockers, we found that carvedilol effectively reversed the mutation-induced gain-of-function channel properties. Notably, the KCNT1 M267T mutation in the mouse hippocampal CA1 pyramidal neurons affected afterhyperpolarization properties and induced neuronal hyperexcitability, which was inhibited by carvedilol. Additionally, carvedilol exhibited antiseizure effects in the kainic acid-induced epilepsy model. CONCLUSION AND IMPLICATION Our findings suggest carvedilol as a new potential candidate for treatment of epilepsies.
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Affiliation(s)
- Chang Di
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center; State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, Beijing, China
| | - Tong Wu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Kai Gao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China
- Children Epilepsy Center, Peking University First Hospital, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
| | - Na Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Huifang Song
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Lili Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Haojie Sun
- UCL School of Pharmacy, University College London, London, UK
| | - Jingyun Yi
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Xinran Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Jiexin Chen
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Mala Shah
- UCL School of Pharmacy, University College London, London, UK
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China
- Children Epilepsy Center, Peking University First Hospital, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
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3
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Shore AN, Li K, Safari M, Qunies AM, Spitznagel BD, Weaver CD, Emmitte KA, Frankel WN, Weston MC. Heterozygous expression of a Kcnt1 gain-of-function variant has differential effects on SST- and PV-expressing cortical GABAergic neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.11.561953. [PMID: 37873369 PMCID: PMC10592778 DOI: 10.1101/2023.10.11.561953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
More than twenty recurrent missense gain-of-function (GOF) mutations have been identified in the sodium-activated potassium (KNa) channel gene KCNT1 in patients with severe developmental and epileptic encephalopathies (DEEs), most of which are resistant to current therapies. Defining the neuron types most vulnerable to KCNT1 GOF will advance our understanding of disease mechanisms and provide refined targets for precision therapy efforts. Here, we assessed the effects of heterozygous expression of a Kcnt1 GOF variant (Y777H) on KNa currents and neuronal physiology among cortical glutamatergic and GABAergic neurons in mice, including those expressing vasoactive intestinal polypeptide (VIP), somatostatin (SST), and parvalbumin (PV), to identify and model the pathogenic mechanisms of autosomal dominant KCNT1 GOF variants in DEEs. Although the Kcnt1-Y777H variant had no effects on glutamatergic or VIP neuron function, it increased subthreshold KNa currents in both SST and PV neurons but with opposite effects on neuronal output; SST neurons became hypoexcitable with a higher rheobase current and lower action potential (AP) firing frequency, whereas PV neurons became hyperexcitable with a lower rheobase current and higher AP firing frequency. Further neurophysiological and computational modeling experiments showed that the differential effects of the Y777H variant on SST and PV neurons are not likely due to inherent differences in these neuron types, but to an increased persistent sodium current in PV, but not SST, neurons. The Y777H variant also increased excitatory input onto, and chemical and electrical synaptic connectivity between, SST neurons. Together, these data suggest differential pathogenic mechanisms, both direct and compensatory, contribute to disease phenotypes, and provide a salient example of how a pathogenic ion channel variant can cause opposite functional effects in closely related neuron subtypes due to interactions with other ionic conductances.
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Affiliation(s)
- Amy N. Shore
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, VA, USA
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA
| | - Keyong Li
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, VA, USA
| | - Mona Safari
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, VA, USA
- Translational Biology, Medicine, and Health Graduate Program, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
| | - Alshaima’a M. Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
- School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Brittany D. Spitznagel
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - C. David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Wayne N. Frankel
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
- Department of Neurology, Columbia University, New York, NY, USA
| | - Matthew C. Weston
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, VA, USA
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA
- Translational Biology, Medicine, and Health Graduate Program, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
- School of Neuroscience, Virginia Tech, Blacksburg, VA, USA
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4
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Yang Y, Tuo J, Zhang J, Xu Z, Luo Z. Pathogenic genes implicated in sleep-related hypermotor epilepsy: a research progress update. Front Neurol 2024; 15:1416648. [PMID: 38966089 PMCID: PMC11222571 DOI: 10.3389/fneur.2024.1416648] [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: 04/12/2024] [Accepted: 06/11/2024] [Indexed: 07/06/2024] Open
Abstract
Sleep-related hypermotor epilepsy (SHE) is a focal epilepsy syndrome characterized by a variable age of onset and heterogeneous etiology. Current literature suggests a prevalence rate of approximately 1.8 per 100,000 persons. The discovery of additional pathogenic genes associated with SHE in recent years has significantly expanded the knowledge and understanding of its pathophysiological mechanisms. Identified SHE pathogenic genes include those related to neuronal ligand- and ion-gated channels (CHRNA4, CHRNB2, CHRNA2, GABRG2, and KCNT1), genes upstream of the mammalian target of rapamycin complex 1 signal transduction pathway (DEPDC5, NPRL2, NPRL3, TSC1, and TSC2), and other genes (CRH, CaBP4, STX1B, and PRIMA1). These genes encode proteins associated with ion channels, neurotransmitter receptors, cell signal transduction, and synaptic transmission. Mutations in these genes can result in the dysregulation of encoded cellular functional proteins and downstream neuronal dysfunction, ultimately leading to epileptic seizures. However, the associations between most genes and the SHE phenotype remain unclear. This article presents a literature review on the research progress of SHE-related pathogenic genes to contribute evidence to genotype-phenotype correlations in SHE and establish the necessary theoretical basis for future SHE treatments.
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Affiliation(s)
- Yufang Yang
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Jinmei Tuo
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Department of Nursing, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Jun Zhang
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Zucai Xu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Zhong Luo
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
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5
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Di Matteo F, Mancuso F, Turcio R, Ciaglia T, Stagno C, Di Chio C, Campiglia P, Bertamino A, Giofrè SV, Ostacolo C, Iraci N. KCNT1 Channel Blockers: A Medicinal Chemistry Perspective. Molecules 2024; 29:2940. [PMID: 38931004 PMCID: PMC11206332 DOI: 10.3390/molecules29122940] [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: 05/14/2024] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Potassium channels have recently emerged as suitable target for the treatment of epileptic diseases. Among potassium channels, KCNT1 channels are the most widely characterized as responsible for several epileptic and developmental encephalopathies. Nevertheless, the medicinal chemistry of KCNT1 blockers is underdeveloped so far. In the present review, we describe and analyse the papers addressing the issue of KCNT1 blockers' development and identification, also evidencing the pros and the cons of the scientific approaches therein described. After a short introduction describing the epileptic diseases and the structure-function of potassium channels, we provide an extensive overview of the chemotypes described so far as KCNT1 blockers, and the scientific approaches used for their identification.
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Affiliation(s)
- Francesca Di Matteo
- Department of Pharmacy, University of Salerno, Via G. Paolo II, 84084 Fisciano, Italy (R.T.); (T.C.)
| | - Francesca Mancuso
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Rita Turcio
- Department of Pharmacy, University of Salerno, Via G. Paolo II, 84084 Fisciano, Italy (R.T.); (T.C.)
| | - Tania Ciaglia
- Department of Pharmacy, University of Salerno, Via G. Paolo II, 84084 Fisciano, Italy (R.T.); (T.C.)
| | - Claudio Stagno
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Carla Di Chio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Pietro Campiglia
- Department of Pharmacy, University of Salerno, Via G. Paolo II, 84084 Fisciano, Italy (R.T.); (T.C.)
| | - Alessia Bertamino
- Department of Pharmacy, University of Salerno, Via G. Paolo II, 84084 Fisciano, Italy (R.T.); (T.C.)
| | - Salvatore Vincenzo Giofrè
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Carmine Ostacolo
- Department of Pharmacy, University of Salerno, Via G. Paolo II, 84084 Fisciano, Italy (R.T.); (T.C.)
| | - Nunzio Iraci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
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6
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Iraci N, Carotenuto L, Ciaglia T, Belperio G, Di Matteo F, Mosca I, Carleo G, Giovanna Basilicata M, Ambrosino P, Turcio R, Puzo D, Pepe G, Gomez-Monterrey I, Soldovieri MV, Di Sarno V, Campiglia P, Miceli F, Bertamino A, Ostacolo C, Taglialatela M. In Silico Assisted Identification, Synthesis, and In Vitro Pharmacological Characterization of Potent and Selective Blockers of the Epilepsy-Associated KCNT1 Channel. J Med Chem 2024; 67:9124-9149. [PMID: 38782404 PMCID: PMC11181338 DOI: 10.1021/acs.jmedchem.4c00268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/28/2024] [Accepted: 04/09/2024] [Indexed: 05/25/2024]
Abstract
Gain-of-function (GoF) variants in KCNT1 channels cause severe, drug-resistant forms of epilepsy. Quinidine is a known KCNT1 blocker, but its clinical use is limited due to severe drawbacks. To identify novel KCNT1 blockers, a homology model of human KCNT1 was built and used to screen an in-house library of compounds. Among the 20 molecules selected, five (CPK4, 13, 16, 18, and 20) showed strong KCNT1-blocking ability in an in vitro fluorescence-based assay. Patch-clamp experiments confirmed a higher KCNT1-blocking potency of these compounds when compared to quinidine, and their selectivity for KCNT1 over hERG and Kv7.2 channels. Among identified molecules, CPK20 displayed the highest metabolic stability; this compound also blocked KCNT2 currents, although with a lower potency, and counteracted GoF effects prompted by 2 recurrent epilepsy-causing KCNT1 variants (G288S and A934T). The present results provide solid rational basis for future design of novel compounds to counteract KCNT1-related neurological disorders.
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Affiliation(s)
- Nunzio Iraci
- Department
of Chemical, Biological, Pharmaceutical and Environmental Sciences
(CHIBIOFARAM), University of Messina, Viale F. Stagno d’Alcontres
31, 98166 Messina, Italy
| | - Lidia Carotenuto
- Department
of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via S. Pansini, 5, 80131 Naples, Italy
| | - Tania Ciaglia
- Department
of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Giorgio Belperio
- Department
of Science and Technology, University of
Sannio, Via F. De Sanctis, 82100 Benevento, Italy
| | - Francesca Di Matteo
- Department
of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Ilaria Mosca
- Department
of Medicine and Health Science Vincenzo Tiberio, University of Molise, Via C. Gazzani, 86100 Campobasso, Italy
| | - Giusy Carleo
- Department
of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via S. Pansini, 5, 80131 Naples, Italy
| | - Manuela Giovanna Basilicata
- Department
of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, P.zza L. Miraglia 2, 80138 Naples, Italy
| | - Paolo Ambrosino
- Department
of Science and Technology, University of
Sannio, Via F. De Sanctis, 82100 Benevento, Italy
| | - Rita Turcio
- Department
of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Deborah Puzo
- Department
of Medicine and Health Science Vincenzo Tiberio, University of Molise, Via C. Gazzani, 86100 Campobasso, Italy
| | - Giacomo Pepe
- Department
of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Isabel Gomez-Monterrey
- Department
of Pharmacy, University Federico II of Naples, Via D. Montesano 49, 80131 Naples, Italy
| | - Maria Virginia Soldovieri
- Department
of Medicine and Health Science Vincenzo Tiberio, University of Molise, Via C. Gazzani, 86100 Campobasso, Italy
| | - Veronica Di Sarno
- Department
of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Pietro Campiglia
- Department
of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Francesco Miceli
- Department
of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via S. Pansini, 5, 80131 Naples, Italy
| | - Alessia Bertamino
- Department
of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Carmine Ostacolo
- Department
of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Maurizio Taglialatela
- Department
of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via S. Pansini, 5, 80131 Naples, Italy
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7
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Qunies AM, Spitznagel BD, Du Y, Peprah PK, Mohamed YK, Weaver CD, Emmitte KA. Structure-Activity Relationship Studies in a Series of Xanthine Inhibitors of SLACK Potassium Channels. Molecules 2024; 29:2437. [PMID: 38893312 PMCID: PMC11173529 DOI: 10.3390/molecules29112437] [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: 04/30/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
Gain-of-function mutations in the KCNT1 gene, which encodes the sodium-activated potassium channel known as SLACK, are associated with the rare but devastating developmental and epileptic encephalopathy known as epilepsy of infancy with migrating focal seizures (EIMFS). The design of small molecule inhibitors of SLACK channels represents a potential therapeutic approach to the treatment of EIMFS, other childhood epilepsies, and developmental disorders. Herein, we describe a hit optimization effort centered on a xanthine SLACK inhibitor (8) discovered via a high-throughput screen. Across three distinct regions of the chemotype, we synthesized 58 new analogs and tested each one in a whole-cell automated patch-clamp assay to develop structure-activity relationships for inhibition of SLACK channels. We further evaluated selected analogs for their selectivity versus a variety of other ion channels and for their activity versus clinically relevant SLACK mutants. Selectivity within the series was quite good, including versus hERG. Analog 80 (VU0948578) was a potent inhibitor of WT, A934T, and G288S SLACK, with IC50 values between 0.59 and 0.71 µM across these variants. VU0948578 represents a useful in vitro tool compound from a chemotype that is distinct from previously reported small molecule inhibitors of SLACK channels.
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Affiliation(s)
- Alshaima’a M. Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | | | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Paul K. Peprah
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Yasmeen K. Mohamed
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - C. David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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8
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Wu J, El-Hassar L, Datta D, Thomas M, Zhang Y, Jenkins DP, DeLuca NJ, Chatterjee M, Gribkoff VK, Arnsten AFT, Kaczmarek LK. Interaction Between HCN and Slack Channels Regulates mPFC Pyramidal Cell Excitability in Working Memory Circuits. Mol Neurobiol 2024; 61:2430-2445. [PMID: 37889366 DOI: 10.1007/s12035-023-03719-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 10/17/2023] [Indexed: 10/28/2023]
Abstract
The ability of monkeys and rats to carry out spatial working memory tasks has been shown to depend on the persistent firing of pyramidal cells in the prefrontal cortex (PFC), arising from recurrent excitatory connections on dendritic spines. These spines express hyperpolarization-activated cyclic nucleotide-gated (HCN) channels whose open state is increased by cAMP signaling, and which markedly alter PFC network connectivity and neuronal firing. In traditional neural circuits, activation of these non-selective cation channels leads to neuronal depolarization and increased firing rate. Paradoxically, cAMP activation of HCN channels in PFC pyramidal cells reduces working memory-related neuronal firing. This suggests that activation of HCN channels may hyperpolarize rather than depolarize these neurons. The current study tested the hypothesis that Na+ influx through HCN channels activates Slack Na+-activated K+ (KNa) channels to hyperpolarize the membrane. We have found that HCN and Slack KNa channels co-immunoprecipitate in cortical extracts and that, by immunoelectron microscopy, they colocalize at postsynaptic spines of PFC pyramidal neurons. A specific blocker of HCN channels, ZD7288, reduces KNa current in pyramidal cells that express both HCN and Slack channels, but has no effect on KNa currents in an HEK cell line expressing Slack without HCN channels, indicating that blockade of HCN channels in neurons reduces K+ current indirectly by lowering Na+ influx. Activation of HCN channels by cAMP in a cell line expressing a Ca2+ reporter results in elevation of cytoplasmic Ca2+, but the effect of cAMP is reversed if the HCN channels are co-expressed with Slack channels. Finally, we used a novel pharmacological blocker of Slack channels to show that inhibition of Slack in rat PFC improves working memory performance, an effect previously demonstrated for blockers of HCN channels. Our results suggest that the regulation of working memory by HCN channels in PFC pyramidal neurons is mediated by an HCN-Slack channel complex that links activation HCN channels to suppression of neuronal excitability.
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Affiliation(s)
- Jing Wu
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Lynda El-Hassar
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Dibyadeep Datta
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Merrilee Thomas
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Yalan Zhang
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - David P Jenkins
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Nicholas J DeLuca
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Manavi Chatterjee
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Valentin K Gribkoff
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Amy F T Arnsten
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA.
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, 06520, USA.
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9
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Wu J, Quraishi IH, Zhang Y, Bromwich M, Kaczmarek LK. Disease-causing Slack potassium channel mutations produce opposite effects on excitability of excitatory and inhibitory neurons. Cell Rep 2024; 43:113904. [PMID: 38457342 PMCID: PMC11013952 DOI: 10.1016/j.celrep.2024.113904] [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: 04/18/2023] [Revised: 12/18/2023] [Accepted: 02/16/2024] [Indexed: 03/10/2024] Open
Abstract
The KCNT1 gene encodes the sodium-activated potassium channel Slack (KCNT1, KNa1.1), a regulator of neuronal excitability. Gain-of-function mutations in humans cause cortical network hyperexcitability, seizures, and severe intellectual disability. Using a mouse model expressing the Slack-R455H mutation, we find that Na+-dependent K+ (KNa) and voltage-dependent sodium (NaV) currents are increased in both excitatory and inhibitory cortical neurons. These increased currents, however, enhance the firing of excitability neurons but suppress that of inhibitory neurons. We further show that the expression of NaV channel subunits, particularly that of NaV1.6, is upregulated and that the length of the axon initial segment and of axonal NaV immunostaining is increased in both neuron types. Our study on the coordinate regulation of KNa currents and the expression of NaV channels may provide an avenue for understanding and treating epilepsies and other neurological disorders.
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Affiliation(s)
- Jing Wu
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Imran H Quraishi
- Department of Neurology, Yale Comprehensive Epilepsy Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - Yalan Zhang
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Mark Bromwich
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06520, USA.
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10
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Hussain R, Lim CX, Shaukat Z, Islam A, Caseley EA, Lippiat JD, Rychkov GY, Ricos MG, Dibbens LM. Drosophila expressing mutant human KCNT1 transgenes make an effective tool for targeted drug screening in a whole animal model of KCNT1-epilepsy. Sci Rep 2024; 14:3357. [PMID: 38336906 PMCID: PMC10858247 DOI: 10.1038/s41598-024-53588-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: 05/10/2023] [Accepted: 02/01/2024] [Indexed: 02/12/2024] Open
Abstract
Mutations in the KCNT1 potassium channel cause severe forms of epilepsy which are poorly controlled with current treatments. In vitro studies have shown that KCNT1-epilepsy mutations are gain of function, significantly increasing K+ current amplitudes. To investigate if Drosophila can be used to model human KCNT1 epilepsy, we generated Drosophila melanogaster lines carrying human KCNT1 with the patient mutation G288S, R398Q or R928C. Expression of each mutant channel in GABAergic neurons gave a seizure phenotype which responded either positively or negatively to 5 frontline epilepsy drugs most commonly administered to patients with KCNT1-epilepsy, often with little or no improvement of seizures. Cannabidiol showed the greatest reduction of the seizure phenotype while some drugs increased the seizure phenotype. Our study shows that Drosophila has the potential to model human KCNT1- epilepsy and can be used as a tool to assess new treatments for KCNT1- epilepsy.
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Affiliation(s)
- Rashid Hussain
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
| | - Chiao Xin Lim
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
- Pharmacy, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia
| | - Zeeshan Shaukat
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
| | - Anowarul Islam
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, 5042, Australia
| | - Emily A Caseley
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Jonathan D Lippiat
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Grigori Y Rychkov
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
- School of Biomedicine, University of Adelaide, Adelaide, SA, 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, 5005, Australia
| | - Michael G Ricos
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
| | - Leanne M Dibbens
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia.
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11
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Malone TJ, Wu J, Zhang Y, Licznerski P, Chen R, Nahiyan S, Pedram M, Jonas EA, Kaczmarek LK. Neuronal potassium channel activity triggers initiation of mRNA translation through binding of translation regulators. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.07.579306. [PMID: 38370631 PMCID: PMC10871293 DOI: 10.1101/2024.02.07.579306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Neuronal activity stimulates mRNA translation crucial for learning and development. While FMRP (Fragile X Mental Retardation Protein) and CYFIP1 (Cytoplasmic FMR1 Interacting Protein 1) regulate translation, the mechanism linking translation to neuronal activity is not understood. We now find that translation is stimulated when FMRP and CYFIP1 translocate to the potassium channel Slack (KCNT1, Slo2.2). When Slack is activated, both factors are released from eIF4E (Eukaryotic Initiation Factor 4E), where they normally inhibit translation initiation. A constitutively active Slack mutation and pharmacological stimulation of the wild-type channel both increase binding of FMRP and CYFIP1 to the channel, enhancing the translation of a reporter for β-actin mRNA in cell lines and the synthesis of β-actin in neuronal dendrites. Slack activity-dependent translation is abolished when both FMRP and CYFIP1 expression are suppressed. The effects of Slack mutations on activity-dependent translation may explain the severe intellectual disability produced by these mutations in humans. HIGHLIGHTS Activation of Slack channels triggers translocation of the FMRP/CYFIP1 complexSlack channel activation regulates translation initiation of a β-actin reporter constructA Slack gain-of-function mutation increases translation of β-actin reporter construct and endogenous cortical β-actinFMRP and CYFIP1 are required for Slack activity-dependent translation. IN BRIEF Malone et al . show that the activation of Slack channels triggers translocation of the FMRP/CYFIP1 complex from the translation initiation factor eIF4E to the channel. This translocation releases eIF4E and stimulates mRNA translation of a reporter for β-actin and cortical β-actin mRNA, elucidating the mechanism that connects neuronal activity with translational regulation.
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12
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Liu R, Sun L, Shi X, Li C, Guo X, Wang Y, Wang X, Zhang K, Wang Y, Wang Q, Wu J. Increased Expression of K Na1.2 Channel by MAPK Pathway Regulates Neuronal Activity Following Traumatic Brain Injury. Neurochem Res 2024; 49:427-440. [PMID: 37875713 DOI: 10.1007/s11064-023-04044-1] [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: 02/05/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/26/2023]
Abstract
Recent studies have indicated that functional abnormalities in the KNa1.2 channel are linked to epileptic encephalopathies. However, the role of KNa1.2 channel in traumatic brain injury (TBI) remains limited. We collected brain tissue from the TBI mice and patients with post-traumatic epilepsy (PTE) to determine changes in KNa1.2 channel following TBI. We also investigated whether the MAPK pathway, which was activated by the released cytokines after injury, regulated KNa1.2 channel in in vitro. Finally, to elucidate the physiological significance of KNa1.2 channel in neuronal excitability, we utilized the null mutant-Kcnt2-/- mice and compared their behavior patterns, seizure susceptibility, and neuronal firing properties to wild type (WT) mice. TBI was induced in both Kcnt2-/- and WT mice to investigate any differences between the two groups under pathological condition. Our findings revealed that the expression of KNa1.2 channel was notably increased only during the acute phase following TBI, while no significant elevation was observed during the late phase. Furthermore, we identified the released cytokines and activated MAPK pathway in the neurons after TBI and confirmed that KNa1.2 channel was enhanced by the MAPK pathway via stimulation of TNF-α. Subsequently, compared to WT mice, neurons from Kcnt2-/- mice showed increased neuronal excitability and Kcnt2-/- mice displayed motor deficits and enhanced seizure susceptibility, which suggested that KNa1.2 channel may be neuroprotective. Therefore, this study suggests that enhanced KNa1.2 channel, facilitated by the inflammatory response, may exert a protective role in an acute phase of the TBI model.
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Affiliation(s)
- Ru Liu
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China
| | - Lei Sun
- Department of Neurology, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Henan University People's Hospital, Zhengzhou, 450008, Henan, China
| | - Xiaorui Shi
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Ci Li
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Xi Guo
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China
| | - Yingting Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Xiu Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Kai Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Yongjun Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China
| | - Qun Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China
- Beijing Institute for Brain Disorders, Beijing, 100070, China
| | - Jianping Wu
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China.
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China.
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, 430070, Hubei, China.
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13
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Khan R, Chaturvedi P, Sahu P, Ludhiadch A, Singh P, Singh G, Munshi A. Role of Potassium Ion Channels in Epilepsy: Focus on Current Therapeutic Strategies. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:67-87. [PMID: 36578258 DOI: 10.2174/1871527322666221227112621] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 11/10/2022] [Accepted: 11/12/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND Epilepsy is one of the prevalent neurological disorders characterized by disrupted synchronization between inhibitory and excitatory neurons. Disturbed membrane potential due to abnormal regulation of neurotransmitters and ion transport across the neural cell membrane significantly contributes to the pathophysiology of epilepsy. Potassium ion channels (KCN) regulate the resting membrane potential and are involved in neuronal excitability. Genetic alterations in the potassium ion channels (KCN) have been reported to result in the enhancement of the release of neurotransmitters, the excitability of neurons, and abnormal rapid firing rate, which lead to epileptic phenotypes, making these ion channels a potential therapeutic target for epilepsy. The aim of this study is to explore the variations reported in different classes of potassium ion channels (KCN) in epilepsy patients, their functional evaluation, and therapeutic strategies to treat epilepsy targeting KCN. METHODOLOGY A review of all the relevant literature was carried out to compile this article. RESULTS A large number of variations have been reported in different genes encoding various classes of KCN. These genetic alterations in KCN have been shown to be responsible for disrupted firing properties of neurons. Antiepileptic drugs (AEDs) are the main therapeutic strategy to treat epilepsy. Some patients do not respond favorably to the AEDs treatment, resulting in pharmacoresistant epilepsy. CONCLUSION Further to address the challenges faced in treating epilepsy, recent approaches like optogenetics, chemogenetics, and genome editing, such as clustered regularly interspaced short palindromic repeats (CRISPR), are emerging as target-specific therapeutic strategies.
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Affiliation(s)
- Rahul Khan
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Pragya Chaturvedi
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Prachi Sahu
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Abhilash Ludhiadch
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Paramdeep Singh
- Department of Radiology, All India Institute of Medical Sciences, Bathinda, Punjab, 151001 India
| | - Gagandeep Singh
- Department of Neurology, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
| | - Anjana Munshi
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
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14
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Qunies AM, Spitznagel BD, Du Y, David Weaver C, Emmitte KA. Design, synthesis, and biological evaluation of a novel series of 1,2,4-oxadiazole inhibitors of SLACK potassium channels: Identification of in vitro tool VU0935685. Bioorg Med Chem 2023; 95:117487. [PMID: 37812884 PMCID: PMC10842602 DOI: 10.1016/j.bmc.2023.117487] [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: 07/05/2023] [Revised: 09/28/2023] [Accepted: 09/29/2023] [Indexed: 10/11/2023]
Abstract
Malignant migrating partial seizure of infancy (MMPSI) is a devastating and pharmacoresistant form of infantile epilepsy. MMPSI has been linked to multiple gain-of-function (GOF) mutations in the KCNT1 gene, which encodes for a potassium channel often referred to as SLACK. SLACK channels are sodium-activated potassium channels distributed throughout the central nervous system (CNS) and the periphery. The investigation described here aims to discover SLACK channel inhibitor tool compounds and profile their pharmacokinetic and pharmacodynamic properties. A SLACK channel inhibitor VU0531245 (VU245) was identified via a high-throughput screen (HTS) campaign. Structure-activity relationship (SAR) studies were conducted in five distinct regions of the hit VU245. VU245 analogs were evaluated for their ability to affect SLACK channel activity using a thallium flux assay in HEK-293 cells stably expressing wild-type (WT) human SLACK. Selected analogs were tested for metabolic stability in mouse liver microsomes and plasma-protein binding in mouse plasma. The same set of analogs was tested via thallium flux for activity versus human A934T SLACK and other structurally related potassium channels, including SLICK and Maxi-K. In addition, potencies for selected VU245 analogs were obtained using whole-cell electrophysiology (EP) assays in CHO cells stably expressing WT human SLACK through an automated patch clamp system. Results revealed that this scaffold tolerates structural changes in some regions, with some analogs demonstrating improved SLACK inhibitory activity, good selectivity against the other channels tested, and modest improvements in metabolic clearance. Analog VU0935685 represents a new, structurally distinct small-molecule inhibitor of SLACK channels that can serve as an in vitro tool for studying this target.
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Affiliation(s)
- Alshaima'a M Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA; School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | | | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - C David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kyle A Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
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15
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Hinckley CA, Zhu Z, Chu JH, Gubbels C, Danker T, Cherry JJ, Whelan CD, Engle SJ, Nguyen V. Functional evaluation of epilepsy-associated KCNT1 variants in multiple cellular systems reveals a predominant gain of function impact on channel properties. Epilepsia 2023; 64:2126-2136. [PMID: 37177976 DOI: 10.1111/epi.17648] [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: 02/03/2023] [Revised: 05/11/2023] [Accepted: 05/11/2023] [Indexed: 05/15/2023]
Abstract
OBJECTIVE Gain of function variants in the sodium-activated potassium channel KCNT1 have been associated with pediatric epilepsy disorders. Here, we systematically examine a spectrum of KCNT1 variants and establish their impact on channel function in multiple cellular systems. METHODS KCNT1 variants identified from published reports and genetic screening of pediatric epilepsy patients were expressed in Xenopus oocytes and HEK cell lines. Variant impact on current magnitude, current-voltage relationships, and sodium ion modulation were examined. RESULTS We determined basic properties of KCNT1 in Xenopus oocyte and HEK systems, including the role of extra- and intracellular sodium in regulating KCNT1 activity. The most common six KCNT1 variants demonstrated strong gain of function (GOF) effects on one or more channel properties. Analysis of 36 total variants identified phenotypic heterogeneity but a strong tendency for pathogenic variants to exert GOF effects on channel properties. By controlling intracellular sodium, we demonstrate that multiple pathogenic KCNT1 variants modulate channel voltage dependence by altering the sensitivity to sodium ions. SIGNIFICANCE This study represents the largest systematic functional examination of KCNT1 variants to date. We both confirm previously reported GOF channel phenotypes and expand the number of variants with in vitro GOF effects. Our data provide further evidence that novel KCNT1 variants identified in epilepsy patients lead to disease through generalizable GOF mechanisms including increases in current magnitude and/or current-voltage relationships.
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Affiliation(s)
| | | | | | | | - Timm Danker
- NMI Technologietransfer GmbH, Reutlingen, Germany
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16
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Wu J, El-Hassar L, Datta D, Thomas M, Zhang Y, Jenkins DP, DeLuca NJ, Chatterjee M, Gribkoff VK, Arnsten AFT, Kaczmarek LK. Interaction Between HCN and Slack Channels Regulates mPFC Pyramidal Cell Excitability and Working Memory. RESEARCH SQUARE 2023:rs.3.rs-2870277. [PMID: 37205397 PMCID: PMC10187370 DOI: 10.21203/rs.3.rs-2870277/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The ability of monkeys and rats to carry out spatial working memory tasks has been shown to depend on the persistent firing of pyramidal cells in the prefrontal cortex (PFC), arising from recurrent excitatory connections on dendritic spines. These spines express hyperpolarization-activated cyclic nucleotide-gated (HCN) channels whose open state is increased by cAMP signaling, and which markedly alter PFC network connectivity and neuronal firing. In traditional neural circuits, activation of these non-selective cation channels leads to neuronal depolarization and increased firing rate. Paradoxically, cAMP activation of HCN channels in PFC pyramidal cells reduces working memory-related neuronal firing. This suggests that activation of HCN channels may hyperpolarize rather than depolarize these neurons. The current study tested the hypothesis that Na+ influx through HCN channels activates Slack Na+-activated K+ (KNa) channels to hyperpolarize the membrane. We have found that HCN and Slack KNa channels coimmunoprecipitate in cortical extracts and that, by immunoelectron microscopy, they colocalize at postsynaptic spines of PFC pyramidal neurons. A specific blocker of HCN channels, ZD7288, reduces KNa current in pyramidal cells that express both HCN and Slack channels, but has no effect on KNa currents in an HEK cell line expressing Slack without HCN channels, indicating that blockade of HCN channels in neurons reduces K+ +current indirectly by lowering Na+ influx. Activation of HCN channels by cAMP in a cell line expressing a Ca2+ reporter results in elevation of cytoplasmic Ca2+, but the effect of cAMP is reversed if the HCN channels are co-expressed with Slack channels. Finally, we used a novel pharmacological blocker of Slack channels to show that inhibition of Slack in rat PFC improves working memory performance, an effect previously demonstrated for blockers of HCN channels. Our results suggest that the regulation of working memory by HCN channels in PFC pyramidal neurons is mediated by an HCN-Slack channel complex that links activation HCN channels to suppression of neuronal excitability.
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Affiliation(s)
- Jing Wu
- Yale University School of Medicine
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17
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Wu J, Quraishi IH, Zhang Y, Bromwich M, Kaczmarek LK. Disease-causing Slack potassium channel mutations produce opposite effects on excitability of excitatory and inhibitory neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.14.528229. [PMID: 36824888 PMCID: PMC9948954 DOI: 10.1101/2023.02.14.528229] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
KCNT1 encodes the sodium-activated potassium channel Slack (KCNT1, K Na 1.1), an important mediator of neuronal membrane excitability. Gain-of-function (GOF) mutations in humans lead cortical network hyperexcitability and seizures, as well as very severe intellectual disability. Using a mouse model of Slack GOF-associated epilepsy, we found that both excitatory and inhibitory neurons of the cerebral cortex have increased Na + -dependent K + (K Na ) currents and voltage-dependent sodium (Na V ) currents. The characteristics of the increased K Na currents were, however, different in the two cell types such that the intrinsic excitability of excitatory neurons was enhanced but that of inhibitory neurons was suppressed. We further showed that the expression of Na V channel subunits, particularly that of Na V 1.6, is upregulated and that the length of the axon initial segment (AIS) and of axonal Na V immunostaining is increased in both neuron types. We found that the proximity of the AIS to the soma is shorter in excitatory neurons than in inhibitory neurons of the mutant animals, potentially contributing to the different effects on membrane excitability. Our study on the coordinate regulation of K Na currents and the expression of Na V channels may provide a new avenue for understanding and treating epilepsies and other neurological disorders. In brief In a genetic mouse model of Na + -activated K + potassium channel gene Slack -related childhood epilepsy, Wu et al . show that a disease-causing gain-of-function (GOF) mutation R455H in Slack channel causes opposite effects on excitability of cortical excitatory and inhibitory neurons. In contrast to heterologous expression systems, they find that the increase in potassium current substantially alters the expression of sodium channel subunits, resulting in increased lengths of axonal initial segments. Highlights GOF mutations in Slack potassium channel cause elevated outward K + currents and inward voltage-dependent Na + (Na V ) currents in cortical neurons Slack GOF does not alter the expression of Slack channel but upregulates the expression of Na V channel Slack GOF enhances the excitability of excitatory neurons but suppresses the firing of inhibitory interneuronsSlack GOF alters the length of AIS in both excitatory and inhibitory neuronsProximity of AIS to the soma is different between excitatory neuron and inhibitory neuron.
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18
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Potassium channelopathies associated with epilepsy-related syndromes and directions for therapeutic intervention. Biochem Pharmacol 2023; 208:115413. [PMID: 36646291 DOI: 10.1016/j.bcp.2023.115413] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
A number of mutations to members of several CNS potassium (K) channel families have been identified which result in rare forms of neonatal onset epilepsy, or syndromes of which one prominent characteristic is a form of epilepsy. Benign Familial Neonatal Convulsions or Seizures (BFNC or BFNS), also referred to as Self-Limited Familial Neonatal Epilepsy (SeLNE), results from mutations in 2 members of the KV7 family (KCNQ) of K channels; while generally self-resolving by about 15 weeks of age, these mutations significantly increase the probability of generalized seizure disorders in the adult, in some cases they result in more severe developmental syndromes. Epilepsy of Infancy with Migrating Focal Seizures (EIMSF), or Migrating Partial Seizures of Infancy (MMPSI), is a rare severe form of epilepsy linked primarily to gain of function mutations in a member of the sodium-dependent K channel family, KCNT1 or SLACK. Finally, KCNMA1 channelopathies, including Liang-Wang syndrome (LIWAS), are rare combinations of neurological symptoms including seizure, movement abnormalities, delayed development and intellectual disabilities, with Liang-Wang syndrome an extremely serious polymalformative syndrome with a number of neurological sequelae including epilepsy. These are caused by mutations in the pore-forming subunit of the large-conductance calcium-activated K channel (BK channel) KCNMA1. The identification of these rare but significant channelopathies has resulted in a resurgence of interest in their treatment by direct pharmacological or genetic modulation. We will briefly review the genetics, biophysics and pharmacology of these K channels, their linkage with the 3 syndromes described above, and efforts to more effectively target these syndromes.
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19
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Burbano LE, Li M, Jancovski N, Jafar-Nejad P, Richards K, Sedo A, Soriano A, Rollo B, Jia L, Gazina EV, Piltz S, Adikusuma F, Thomas PQ, Kopsidas H, Rigo F, Reid CA, Maljevic S, Petrou S. Antisense oligonucleotide therapy for KCNT1 encephalopathy. JCI Insight 2022; 7:146090. [PMID: 36173683 PMCID: PMC9746904 DOI: 10.1172/jci.insight.146090] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 09/27/2022] [Indexed: 01/12/2023] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are characterized by pharmaco-resistant seizures with concomitant intellectual disability. Epilepsy of infancy with migrating focal seizures (EIMFS) is one of the most severe of these syndromes. De novo variants in ion channels, including gain-of-function variants in KCNT1, which encodes for sodium activated potassium channel protein KNa1.1, have been found to play a major role in the etiology of EIMFS. Here, we test a potential precision therapeutic approach in KCNT1-associated DEE using a gene-silencing antisense oligonucleotide (ASO) approach. We generated a mouse model carrying the KCNT1 p.P924L pathogenic variant; only the homozygous animals presented with the frequent, debilitating seizures and developmental compromise that are seen in patients. After a single intracerebroventricular bolus injection of a Kcnt1 gapmer ASO in symptomatic mice at postnatal day 40, seizure frequency was significantly reduced, behavioral abnormalities improved, and overall survival was extended compared with mice treated with a control ASO (nonhybridizing sequence). ASO administration at neonatal age was also well tolerated and effective in controlling seizures and extending the life span of treated animals. The data presented here provide proof of concept for ASO-based gene silencing as a promising therapeutic approach in KCNT1-associated epilepsies.
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Affiliation(s)
- Lisseth Estefania Burbano
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Melody Li
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Nikola Jancovski
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | | | - Kay Richards
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Alicia Sedo
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | | | - Ben Rollo
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Linghan Jia
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Elena V. Gazina
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Sandra Piltz
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Fatwa Adikusuma
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Paul Q. Thomas
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.,South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Helen Kopsidas
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | - Christopher A. Reid
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.,Praxis Precision Medicines, Cambridge, Massachusetts, USA
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20
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Rychkov GY, Shaukat Z, Lim CX, Hussain R, Roberts BJ, Bonardi CM, Rubboli G, Meaney BF, Whitney R, Møller RS, Ricos MG, Dibbens LM. Functional Effects of Epilepsy Associated KCNT1 Mutations Suggest Pathogenesis via Aberrant Inhibitory Neuronal Activity. Int J Mol Sci 2022; 23:ijms232315133. [PMID: 36499459 PMCID: PMC9740882 DOI: 10.3390/ijms232315133] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
KCNT1 (K+ channel subfamily T member 1) is a sodium-activated potassium channel highly expressed in the nervous system which regulates neuronal excitability by contributing to the resting membrane potential and hyperpolarisation following a train of action potentials. Gain of function mutations in the KCNT1 gene are the cause of neurological disorders associated with different forms of epilepsy. To gain insights into the underlying pathobiology we investigated the functional effects of 9 recently published KCNT1 mutations, 4 previously studied KCNT1 mutations, and one previously unpublished KCNT1 variant of unknown significance. We analysed the properties of KCNT1 potassium currents and attempted to find a correlation between the changes in KCNT1 characteristics due to the mutations and severity of the neurological disorder they cause. KCNT1 mutations identified in patients with epilepsy were introduced into the full length human KCNT1 cDNA using quick-change site-directed mutagenesis protocol. Electrophysiological properties of different KCNT1 constructs were investigated using a heterologous expression system (HEK293T cells) and patch clamping. All mutations studied, except T314A, increased the amplitude of KCNT1 currents, and some mutations shifted the voltage dependence of KCNT1 open probability, increasing the proportion of channels open at the resting membrane potential. The T314A mutation did not affect KCNT1 current amplitude but abolished its voltage dependence. We observed a positive correlation between the severity of the neurological disorder and the KCNT1 channel open probability at resting membrane potential. This suggests that gain of function KCNT1 mutations cause epilepsy by increasing resting potassium conductance and suppressing the activity of inhibitory neurons. A reduction in action potential firing in inhibitory neurons due to excessively high resting potassium conductance leads to disinhibition of neural circuits, hyperexcitability and seizures.
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Affiliation(s)
- Grigori Y. Rychkov
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA 5005, Australia
- Correspondence:
| | - Zeeshan Shaukat
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Chiao Xin Lim
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Rashid Hussain
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Ben J. Roberts
- Clinical and Health Sciences, Health and Biomedical Innovation, University of South Australia, Adelaide, SA 5000, Australia
| | - Claudia M. Bonardi
- Department of Woman’s and Child’s Health, Padua University Hospital, 35128 Padua, Italy
- The Danish Epilepsy Centre, 4293 Dianalund, Denmark
| | - Guido Rubboli
- Denmark Department of Clinical Medicine, Copenhagen University Hospital, 2200 Copenhagen, Denmark
| | - Brandon F. Meaney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON 8SL 4L8, Canada
| | - Robyn Whitney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON 8SL 4L8, Canada
| | - Rikke S. Møller
- Department of Epilepsy Genetics and Personalized Treatment, Member of the ERN EpiCARE, The Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5000 Odense, Denmark
| | - Michael G. Ricos
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Leanne M. Dibbens
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
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21
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Miziak B, Czuczwar SJ. Approaches for the discovery of drugs that target K Na 1.1 channels in KCNT1-associated epilepsy. Expert Opin Drug Discov 2022; 17:1313-1328. [PMID: 36408599 DOI: 10.1080/17460441.2023.2150164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
INTRODUCTION There are approximately 70 million people with epilepsy and about 30% of patients are not satisfactorily treated. A link between gene mutations and epilepsy is well documented. A number of pathological variants of KCNT1 gene (encoding the weakly voltage-dependent sodium-activated potassium channel - KNa 1.1) mutations has been found. For instance, epilepsy of infancy with migrating focal seizures, autosomal sleep-related hypermotor epilepsy or Ohtahara syndrome have been associated with KCNT1 gene mutations. AREAS COVERED Several methods for studies on KNa 1.1 channels have been reviewed - patch clamp analysis, Förster resonance energy transfer spectroscopy and whole-exome sequencing. The authors also review available drugs for the management of KCNT1 epilepsies. EXPERT OPINION The current methods enable deeper insights into electrophysiology of KNa 1.1 channels or its functioning in different activation states. It is also possible to identify a given KCNT1 mutation. Quinidine and cannabidiol show variable efficacy as add-on to baseline antiepileptic drugs so more effective treatments are required. A combined approach with the methods shown above, in silico methods and the animal model of KCNT1 epilepsies seems likely to create personalized treatment of patients with KCNT1 gene mutations.
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Affiliation(s)
- Barbara Miziak
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
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22
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Qunies AM, Mishra NM, Spitznagel BD, Du Y, Acuña VS, David Weaver C, Emmitte KA. Structure-activity relationship studies in a new series of 2-amino-N-phenylacetamide inhibitors of Slack potassium channels. Bioorg Med Chem Lett 2022; 76:129013. [PMID: 36184030 PMCID: PMC10230575 DOI: 10.1016/j.bmcl.2022.129013] [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: 07/14/2022] [Revised: 09/20/2022] [Accepted: 09/26/2022] [Indexed: 11/02/2022]
Abstract
In this Letter we describe structure-activity relationship (SAR) studies conducted in five distinct regions of a new 2-amino-N-phenylacetamides series of Slack potassium channel inhibitors exemplified by recently disclosed high-throughput screening (HTS) hit VU0606170 (4). New analogs were screened in a thallium (Tl+) flux assay in HEK-293 cells stably expressing wild-type human (WT) Slack. Selected analogs were screened in Tl+ flux versus A934T Slack and other Slo family members Slick and Maxi-K and evaluated in whole-cell electrophysiology (EP) assays using an automated patch clamp system. Results revealed the series to have flat SAR with significant structural modifications resulting in a loss of Slack activity. More minor changes led to compounds with Slack activity and Slo family selectivity similar to the HTS hit.
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Affiliation(s)
- Alshaima'a M Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA; Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Nigam M Mishra
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | | | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Valerie S Acuña
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - C David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kyle A Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA.
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23
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Induced pluripotent stem cells (SHCDNi006-A cells) isolated from the peripheral blood mononuclear cells of a five-month-old Chinese girl with the heterozygous missense mutation (c.2800 G>A) in the KCNT1 gene. Stem Cell Res 2022; 62:102798. [DOI: 10.1016/j.scr.2022.102798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/24/2022] [Accepted: 04/29/2022] [Indexed: 11/23/2022] Open
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24
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Liu R, Sun L, Wang Y, Jia M, Wang Q, Cai X, Wu J. Double-edged Role of K Na Channels in Brain Tuning: Identifying Epileptogenic Network Micro-Macro Disconnection. Curr Neuropharmacol 2022; 20:916-928. [PMID: 34911427 PMCID: PMC9881102 DOI: 10.2174/1570159x19666211215104829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/09/2021] [Accepted: 12/10/2021] [Indexed: 11/22/2022] Open
Abstract
Epilepsy is commonly recognized as a disease driven by generalized hyperexcited and hypersynchronous neural activity. Sodium-activated potassium channels (KNa channels), which are encoded by the Slo 2.2 and Slo 2.1 genes, are widely expressed in the central nervous system and considered as "brakes" to adjust neuronal adaptation through regulating action potential threshold or after-hyperpolarization under physiological condition. However, the variants in KNa channels, especially gain-of-function variants, have been found in several childhood epileptic conditions. Most previous studies focused on mapping the epileptic network on the macroscopic scale while ignoring the value of microscopic changes. Notably, paradoxical role of KNa channels working on individual neuron/microcircuit and the macroscopic epileptic expression highlights the importance of understanding epileptogenic network through combining microscopic and macroscopic methods. Here, we first illustrated the molecular and physiological function of KNa channels on preclinical seizure models and patients with epilepsy. Next, we summarized current hypothesis on the potential role of KNa channels during seizures to provide essential insight into what emerged as a micro-macro disconnection at different levels. Additionally, we highlighted the potential utility of KNa channels as therapeutic targets for developing innovative anti-seizure medications.
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Affiliation(s)
- Ru Liu
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China;,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China;,China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Lei Sun
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China;,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China;,China National Clinical Research Center for Neurological Diseases, Beijing, China
| | | | - Meng Jia
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China;,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China;,China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Qun Wang
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China;,China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Xiang Cai
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China;,Address correspondence to these authors at the Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Tel: +0086-18062552085; E-mail: Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China; Tel: +0086-13319285082; E-mail:
| | - Jianping Wu
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China;,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China;,China National Clinical Research Center for Neurological Diseases, Beijing, China;,Address correspondence to these authors at the Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Tel: +0086-18062552085; E-mail: Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China; Tel: +0086-13319285082; E-mail:
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25
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Gertler TS, Cherian S, DeKeyser JM, Kearney JA, George AL. K Na1.1 gain-of-function preferentially dampens excitability of murine parvalbumin-positive interneurons. Neurobiol Dis 2022; 168:105713. [PMID: 35346832 PMCID: PMC9169414 DOI: 10.1016/j.nbd.2022.105713] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/07/2022] [Accepted: 03/24/2022] [Indexed: 10/25/2022] Open
Abstract
KCNT1 encodes the sodium-activated potassium channel KNa1.1, expressed preferentially in the frontal cortex, hippocampus, cerebellum, and brainstem. Pathogenic missense variants in KCNT1 are associated with intractable epilepsy, namely epilepsy of infancy with migrating focal seizures (EIMFS), and sleep-related hypermotor epilepsy (SHE). In vitro studies of pathogenic KCNT1 variants support predominantly a gain-of-function molecular mechanism, yet how these variants behave in a neuron or ultimately drive formation of an epileptogenic circuit is an important and timely question. Using CRISPR/Cas9 gene editing, we introduced a gain-of-function variant into the endogenous mouse Kcnt1 gene. Compared to wild-type (WT) littermates, heterozygous and homozygous knock-in mice displayed greater seizure susceptibility to the chemoconvulsants kainate and pentylenetetrazole (PTZ), but not to flurothyl. Using acute slice electrophysiology in heterozygous and homozygous Kcnt1 knock-in and WT littermates, we demonstrated that CA1 hippocampal pyramidal neurons exhibit greater amplitude of miniature inhibitory postsynaptic currents in mutant mice with no difference in frequency, suggesting greater inhibitory tone associated with the Kcnt1 mutation. To address alterations in GABAergic signaling, we bred Kcnt1 knock-in mice to a parvalbumin-tdTomato reporter line, and found that parvalbumin-expressing (PV+) interneurons failed to fire repetitively with large amplitude current injections and were more prone to depolarization block. These alterations in firing can be recapitulated by direct application of the KNa1.1 channel activator loxapine in WT but are occluded in knock-in littermates, supporting a direct channel gain-of-function mechanism. Taken together, these results suggest that KNa1.1 gain-of-function dampens interneuron excitability to a greater extent than it impacts pyramidal neuron excitability, driving seizure susceptibility in a mouse model of KCNT1-associated epilepsy.
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Affiliation(s)
- Tracy S Gertler
- Division of Pediatric Neurology, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, United States of America; Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America.
| | - Suraj Cherian
- Division of Pediatric Neurology, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, United States of America; Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Jean-Marc DeKeyser
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Jennifer A Kearney
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America.
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26
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Small-molecule inhibitors of Slack potassium channels as potential therapeutics for childhood epilepsies. Pharm Pat Anal 2022; 11:45-56. [PMID: 35369761 PMCID: PMC9260495 DOI: 10.4155/ppa-2022-0002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Slack channels are sodium-activated potassium channels that are encoded by the KCNT1 gene. Several KCNT1 gain of function mutations have been linked to malignant migrating partial seizures of infancy. Quinidine is an anti-arrhythmic drug that functions as a moderately potent inhibitor of Slack channels; however, quinidine use is limited by its poor selectivity, safety and pharmacokinetic profile. Slack channels represent an interesting target for developing novel therapeutics for the treatment of malignant migrating partial seizures of infancy and other childhood epilepsies; thus, ongoing efforts are directed toward the discovery of small-molecules that inhibit Slack currents. This review summarizes patent applications published in 2020-2021 that describe the discovery of novel small-molecule Slack inhibitors.
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27
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Dixon RE, Navedo MF, Binder MD, Santana LF. Mechanisms and Physiological Implications of Cooperative Gating of Ion Channels Clusters. Physiol Rev 2021; 102:1159-1210. [PMID: 34927454 DOI: 10.1152/physrev.00022.2021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ion channels play a central role in the regulation of nearly every cellular process. Dating back to the classic 1952 Hodgkin-Huxley model of the generation of the action potential, ion channels have always been thought of as independent agents. A myriad of recent experimental findings exploiting advances in electrophysiology, structural biology, and imaging techniques, however, have posed a serious challenge to this long-held axiom as several classes of ion channels appear to open and close in a coordinated, cooperative manner. Ion channel cooperativity ranges from variable-sized oligomeric cooperative gating in voltage-gated, dihydropyridine-sensitive Cav1.2 and Cav1.3 channels to obligatory dimeric assembly and gating of voltage-gated Nav1.5 channels. Potassium channels, transient receptor potential channels, hyperpolarization cyclic nucleotide-activated channels, ryanodine receptors (RyRs), and inositol trisphosphate receptors (IP3Rs) have also been shown to gate cooperatively. The implications of cooperative gating of these ion channels range from fine tuning excitation-contraction coupling in muscle cells to regulating cardiac function and vascular tone, to modulation of action potential and conduction velocity in neurons and cardiac cells, and to control of pace-making activity in the heart. In this review, we discuss the mechanisms leading to cooperative gating of ion channels, their physiological consequences and how alterations in cooperative gating of ion channels may induce a range of clinically significant pathologies.
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Affiliation(s)
- Rose Ellen Dixon
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA, United States
| | - Marc D Binder
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
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28
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Slo2/K Na Channels in Drosophila Protect against Spontaneous and Induced Seizure-like Behavior Associated with an Increased Persistent Na + Current. J Neurosci 2021; 41:9047-9063. [PMID: 34544836 DOI: 10.1523/jneurosci.0290-21.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/20/2021] [Accepted: 09/13/2021] [Indexed: 11/21/2022] Open
Abstract
Na+ sensitivity is a unique feature of Na+-activated K+ (KNa) channels, making them naturally suited to counter a sudden influx in Na+ ions. As such, it has long been suggested that KNa channels may serve a protective function against excessive excitation associated with neuronal injury and disease. This hypothesis, however, has remained largely untested. Here, we examine KNa channels encoded by the Drosophila Slo2 (dSlo2) gene in males and females. We show that dSlo2/KNa channels are selectively expressed in cholinergic neurons in the adult brain, as well as in glutamatergic motor neurons, where dampening excitation may function to inhibit global hyperactivity and seizure-like behavior. Indeed, we show that effects of feeding Drosophila a cholinergic agonist are exacerbated by the loss of dSlo2/KNa channels. Similar to mammalian Slo2/KNa channels, we show that dSlo2/KNa channels encode a TTX-sensitive K+ conductance, indicating that dSlo2/KNa channels can be activated by Na+ carried by voltage-dependent Na+ channels. We then tested the role of dSlo2/KNa channels in established genetic seizure models in which the voltage-dependent persistent Na+ current (INap) is elevated. We show that the absence of dSlo2/KNa channels increased susceptibility to mechanically induced seizure-like behavior. Similar results were observed in WT flies treated with veratridine, an enhancer of INap Finally, we show that loss of dSlo2/KNa channels in both genetic and pharmacologically primed seizure models resulted in the appearance of spontaneous seizures. Together, our results support a model in which dSlo2/KNa channels, activated by neuronal overexcitation, contribute to a protective threshold to suppress the induction of seizure-like activity.SIGNIFICANCE STATEMENT Slo2/KNa channels are unique in that they constitute a repolarizing K+ pore that is activated by the depolarizing Na+ ion, making them naturally suited to function as a protective "brake" against overexcitation and Na+ overload. Here, we test this hypothesis in vivo by examining how a null mutation of the Drosophila Slo2 (dSlo2)/KNa gene affects seizure-like behavior in genetic and pharmacological models of epilepsy. We show that indeed the loss of dSlo2/KNa channels results in increased incidence and severity of induced seizure behavior, as well as the appearance of spontaneous seizure activity. Our results advance our understanding of neuronal excitability and protective mechanisms that preserve normal physiology and the suppression of seizure susceptibility.
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29
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Zhang Y, Ali SR, Nabbout R, Barcia G, Kaczmarek LK. A KCNC1 mutation in epilepsy of infancy with focal migrating seizures produces functional channels that fail to be regulated by PKC phosphorylation. J Neurophysiol 2021; 126:532-539. [PMID: 34232791 DOI: 10.1152/jn.00257.2021] [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] [Indexed: 12/21/2022] Open
Abstract
Channelopathies caused by mutations in genes encoding ion channels generally produce a clear change in channel function. Accordingly, mutations in KCNC1, which encodes the voltage-dependent Kv3.1 potassium channel, result in progressive myoclonus epilepsy as well as other developmental and epileptic encephalopathies, and these have been shown to reduce or fully abolish current amplitude. One exception to this is the mutation A513V Kv3.1b, located in the cytoplasmic C-terminal domain of the channel protein. This de novo variant was detected in a patient with epilepsy of infancy with focal migrating seizures (EIFMS), but no difference could be detected between A513V Kv3.1 current and that of wild-type Kv3.1. Using both biochemical and electrophysiological approaches, we have now confirmed that this variant produces functional channels but find that the A513V mutation renders the channel completely insensitive to regulation by phosphorylation at S503, a nearby regulatory site in the C-terminus. In this respect, the mutation resembles those in another channel, KCNT1, which are the major cause of EIFMS. Because the amplitude of Kv3.1 current is constantly adjusted by phosphorylation in vivo, our findings suggest that loss of such regulation contributes to EIFMS phenotype and emphasize the role of channel modulation for normal neuronal function.NEW & NOTEWORTHY Ion channel mutations that cause serious human diseases generally alter the biophysical properties or expression of the channel. We describe a de novo mutation in the Kv3.1 potassium channel that causes severe intellectual disability with early-onset epilepsy. The properties of this channel appear identical to those of wild-type channels, but the mutation prevents phosphorylation of the channel by protein kinase C. Our findings emphasize the role of channel modulation in normal brain function.
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Affiliation(s)
- Yalan Zhang
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut
| | - Syed R Ali
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut
| | - Rima Nabbout
- Department of Pediatric Neurology, Necker-Enfants Malades Hospital, Centre de Référence Épilepsies Rares, Member of ERN EPICARE, Institut Imagine, Université de Paris, Paris, France
| | - Giulia Barcia
- Department of Pediatric Neurology, Necker-Enfants Malades Hospital, Centre de Référence Épilepsies Rares, Member of ERN EPICARE, Institut Imagine, Université de Paris, Paris, France.,Department of Medical Genetics, Necker-Enfants Malades Hospital, Université de Paris, Paris, France
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut.,Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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30
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Abstract
Genetic testing has yielded major advances in our understanding of the causes of epilepsy. Seizures remain resistant to treatment in a significant proportion of cases, particularly in severe, childhood-onset epilepsy, the patient population in which an underlying causative genetic variant is most likely to be identified. A genetic diagnosis can be explanatory as to etiology, and, in some cases, might suggest a therapeutic approach; yet, a clear path from genetic diagnosis to treatment remains unclear in most cases. Here, we discuss theoretical considerations behind the attempted use of small molecules for the treatment of genetic epilepsies, which is but one among various approaches currently under development. We explore a few salient examples and consider the future of the small molecule approach for genetic epilepsies. We conclude that significant additional work is required to understand how genetic variation leads to dysfunction of epilepsy-associated protein targets, and how this impacts the function of diverse subtypes of neurons embedded within distributed brain circuits to yield epilepsy and epilepsy-associated comorbidities. A syndrome- or even variant-specific approach may be required to achieve progress. Advances in the field will require improved methods for large-scale target validation, compound identification and optimization, and the development of accurate model systems that reflect the core features of human epilepsy syndromes, as well as novel approaches towards clinical trials of such compounds in small rare disease cohorts.
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Affiliation(s)
- Ethan M Goldberg
- Department of Pediatrics, Division of Neurology, Abramson Research Center, The Epilepsy Neurogenetics Initiative, The Children's Hospital of Philadelphia, Abramson Research Center Room 502A, 19104, Philadelphia, PA, USA.
- Departments of Neurology and Neuroscience, The University of Pennsylvania Perelman School of Medicine, 19104, Philadelphia, PA, USA.
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31
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Cole BA, Clapcote SJ, Muench SP, Lippiat JD. Targeting K Na1.1 channels in KCNT1-associated epilepsy. Trends Pharmacol Sci 2021; 42:700-713. [PMID: 34074526 DOI: 10.1016/j.tips.2021.05.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/30/2021] [Accepted: 05/05/2021] [Indexed: 12/19/2022]
Abstract
Gain-of-function (GOF) pathogenic variants of KCNT1, the gene encoding the largest known potassium channel subunit, KNa1.1, are associated with developmental and epileptic encephalopathies accompanied by severe psychomotor and intellectual disabilities. Blocking hyperexcitable KNa1.1 channels with quinidine, a class I antiarrhythmic drug, has shown variable success in patients in part because of dose-limiting off-target effects, poor blood-brain barrier (BBB) penetration, and low potency. In recent years, high-resolution cryogenic electron microscopy (cryo-EM) structures of the chicken KNa1.1 channel in different activation states have been determined, and animal models of the diseases have been generated. Alongside increasing information about the functional effects of GOF pathogenic variants on KNa1.1 channel behaviour and how they lead to hyperexcitability, these tools will facilitate the development of more effective treatment strategies. We review the range of KCNT1 variants and their functional effects, the challenges posed by current treatment strategies, and recent advances in finding more potent and selective therapeutic interventions for KCNT1-related epilepsies.
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Affiliation(s)
- Bethan A Cole
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Steven J Clapcote
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Stephen P Muench
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
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32
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Venti V, Ciccia L, Scalia B, Sciuto L, Cimino C, Marino S, Praticò AD, Falsaperla R. KCNT1-Related Epilepsy: A Review. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1728688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
KCNT1 gene encodes the sodium-dependent potassium channel reported as a causal factor for several different epileptic disorders. The gene has been also linked with cardiac disorders and in a family to sudden unexpected death in epilepsy. KCNT1 mutations, in most cases, result in a gain of function causing a neuronal hyperpolarization with loss of inhibition. Many early-onset epileptic encephalopathies related to gain of function of KCNT1 gene have been described, most often associated with two phenotypes: malignant migrating focal seizures of infancy and familial autosomal-dominant nocturnal frontal lobe epilepsy; however, there is no clear phenotype–genotype correlation, in fact same mutations have been represented in patients with West syndrome, Ohtahara syndrome, and early myoclonic encephalopathy. Additional neurologic features include intellectual disability, psychiatric disorders, hypotonia, microcephaly, strabismus, and movement disorders. Conventional anticonvulsant, vagal stimulation, and ketogenic diet have been used in the absence of clinical benefit in individuals with KCNT1-related epilepsy; in some patients, quinidine therapy off-label has been practiced successfully. This review aims to describe the characteristics of the gene, the phenotypes related to genetic mutations with the possible genotype–phenotype correlations and the treatments proposed to date, discussing the comorbidities reported in the literature.
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Affiliation(s)
- Valeria Venti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Lina Ciccia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Bruna Scalia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Laura Sciuto
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Carla Cimino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Simona Marino
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
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33
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Shrivastava R, Ghosh S. Collective Dynamics of Ion Channels on Bilayer Lipid Membranes. ACS OMEGA 2021; 6:7544-7557. [PMID: 33778266 PMCID: PMC7992176 DOI: 10.1021/acsomega.0c06061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 02/02/2021] [Indexed: 05/06/2023]
Abstract
Ion channels self-organize on cellular and organelle membranes as clusters and mutually modulate their gating behavior. It has been reported that the efficient information transfer is achieved by cooperative clustering of ion channels. To address the origin and nature of collective dynamics in ion channel clusters, a statistical mechanical model, namely, the Zimm-Bragg-type model in two dimensions with unequal weight distribution in channel-channel interactions, has been proposed. Nearest neighbor interaction along with next-nearest neighbor interaction has been considered, assuming symmetric spatial organization. The multichannel bilayer electrophysiology recordings of the voltage-dependent anion channel (VDAC) from rat brain mitochondria have been analyzed in order to test and further extend the model. The model successfully describes the multichannel gating behavior and self-organization of the VDAC cluster.
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34
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Kuchenbuch M, Nabbout R, Yochum M, Sauleau P, Modolo J, Wendling F, Benquet P. In silico model reveals the key role of GABA in KCNT1-epilepsy in infancy with migrating focal seizures. Epilepsia 2021; 62:683-697. [PMID: 33617692 DOI: 10.1111/epi.16834] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/08/2020] [Accepted: 01/18/2021] [Indexed: 02/06/2023]
Abstract
OBJECTIVE This study was undertaken to investigate how gain of function (GOF) of slack channel due to a KCNT1 pathogenic variant induces abnormal neuronal cortical network activity and generates specific electroencephalographic (EEG) patterns of epilepsy in infancy with migrating focal seizures. METHODS We used detailed microscopic computational models of neurons to explore the impact of GOF of slack channel (explicitly coded) on each subtype of neurons and on a cortical micronetwork. Then, we adapted a thalamocortical macroscopic model considering results obtained in detailed models and immature properties related to epileptic brain in infancy. Finally, we compared simulated EEGs resulting from the macroscopic model with interictal and ictal patterns of affected individuals using our previously reported EEG markers. RESULTS The pathogenic variants of KCNT1 strongly decreased the firing rate properties of γ-aminobutyric acidergic (GABAergic) interneurons and, to a lesser extent, those of pyramidal cells. This change led to hyperexcitability with increased synchronization in a cortical micronetwork. At the macroscopic scale, introducing slack GOF effect resulted in epilepsy of infancy with migrating focal seizures (EIMFS) EEG interictal patterns. Increased excitation-to-inhibition ratio triggered seizure, but we had to add dynamic depolarizing GABA between somatostatin-positive interneurons and pyramidal cells to obtain migrating seizure. The simulated migrating seizures were close to EIMFS seizures, with similar values regarding the delay between the different ictal activities (one of the specific EEG markers of migrating focal seizures due to KCNT1 pathogenic variants). SIGNIFICANCE This study illustrates the interest of biomathematical models to explore pathophysiological mechanisms bridging the gap between the functional effect of gene pathogenic variants and specific EEG phenotype. Such models can be complementary to in vitro cellular and animal models. This multiscale approach provides an in silico framework that can be further used to identify candidate innovative therapies.
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Affiliation(s)
- Mathieu Kuchenbuch
- LTSI-U1099, Université de Rennes 1, INSERM, Rennes, France.,Department of Pediatric Neurology, Reference Center for Rare Epilepsies, Hôpital Necker-Enfants malades, member of European Network EPICARE, Paris, France.,Laboratory of Translational Research for Neurological Disorders (UMR 1163), IHU Imagine Institute of Genetic Diseases, INSERM, University of Paris, Paris, France
| | - Rima Nabbout
- Department of Pediatric Neurology, Reference Center for Rare Epilepsies, Hôpital Necker-Enfants malades, member of European Network EPICARE, Paris, France.,Laboratory of Translational Research for Neurological Disorders (UMR 1163), IHU Imagine Institute of Genetic Diseases, INSERM, University of Paris, Paris, France
| | - Maxime Yochum
- LTSI-U1099, Université de Rennes 1, INSERM, Rennes, France
| | - Paul Sauleau
- CHU de Rennes (Department of Neurophysiology), "Behavior and Basal Ganglia" Research Unit (EA4712), University of Rennes, Rennes, France
| | - Julien Modolo
- LTSI-U1099, Université de Rennes 1, INSERM, Rennes, France
| | | | - Pascal Benquet
- LTSI-U1099, Université de Rennes 1, INSERM, Rennes, France
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35
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The Na +-activated K + channel Slack contributes to synaptic development and plasticity. Cell Mol Life Sci 2021; 78:7569-7587. [PMID: 34664085 PMCID: PMC8629810 DOI: 10.1007/s00018-021-03953-0] [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: 01/20/2021] [Revised: 09/08/2021] [Accepted: 09/22/2021] [Indexed: 11/29/2022]
Abstract
Human mutations of the Na+-activated K+ channel Slack (KCNT1) are associated with epilepsy and intellectual disability. Accordingly, Slack knockout mice (Slack-/-) exhibit cognitive flexibility deficits in distinct behavioral tasks. So far, however, the underlying causes as well as the role of Slack in hippocampus-dependent memory functions remain enigmatic. We now report that infant (P6-P14) Slack-/- lack both hippocampal LTD and LTP, likely due to impaired NMDA receptor (NMDAR) signaling. Postsynaptic GluN2B levels are reduced in infant Slack-/-, evidenced by lower amplitudes of NMDAR-meditated excitatory postsynaptic potentials. Low GluN2B affected NMDAR-mediated Ca2+-influx, rendering cultured hippocampal Slack-/-neurons highly insensitive to the GluN2B-specific inhibitor Ro 25-6981. Furthermore, dephosphorylation of the AMPA receptor (AMPAR) subunit GluA1 at S845, which is involved in AMPAR endocytosis during homeostatic and neuromodulator-regulated plasticity, is reduced after chemical LTD (cLTD) in infant Slack-/-. We additionally detect a lack of mGluR-induced LTD in infant Slack-/-, possibly caused by upregulation of the recycling endosome-associated small GTPase Rab4 which might accelerate AMPAR recycling from early endosomes. Interestingly, LTP and mGluR LTD, but not LTD and S845 dephosphorylation after cLTD are restored in adult Slack-/-. This together with normalized expression levels of GluN2B and Rab4 hints to developmental "restoration" of LTP expression despite Slack ablation, whereas in infant and adult brain, NMDAR-dependent LTD induction depends on this channel. Based on the present findings, NMDAR and vesicular transport might represent novel targets for the therapy of intellectual disability associated with Slack mutations. Consequently, careful modulation of hippocampal Slack activity should also improve learning abilities.
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36
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Spitznagel BD, Mishra NM, Qunies AM, Prael FJ, Du Y, Kozek KA, Lazarenko RM, Denton JS, Emmitte KA, Weaver CD. VU0606170, a Selective Slack Channels Inhibitor, Decreases Calcium Oscillations in Cultured Cortical Neurons. ACS Chem Neurosci 2020; 11:3658-3671. [PMID: 33143429 DOI: 10.1021/acschemneuro.0c00583] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Malignant migrating partial seizures of infancy is a rare, devastating form of epilepsy most commonly associated with gain-of-function mutations in the potassium channel, Slack. Not only is this condition almost completely pharmacoresistant, there are not even selective drug-like tools available to evaluate whether inhibition of these overactivated, mutant Slack channels may represent a viable path forward toward new antiepileptic therapies. Therefore, we used a high-throughput thallium flux assay to screen a drug-like, 100 000-compound library in search of inhibitors of both wild-type and a disease-associated mutant Slack channel. Using this approach, we discovered VU0606170, a selective Slack channel inhibitor with low micromolar potency. Critically, VU0606170 also proved effective at significantly decreasing the firing rate in overexcited, spontaneously firing cortical neuron cultures. Taken together, our data provide compelling evidence that selective inhibition of Slack channel activity can be achieved with small molecules and that inhibition of Slack channel activity in neurons produces efficacy consistent with an antiepileptic effect. Thus, the identification of VU0606170 provides a much-needed tool for advancing our understanding of the role of the Slack channel in normal physiology and disease as well as its potential as a target for therapeutic intervention.
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Affiliation(s)
- Brittany D. Spitznagel
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Nigam M. Mishra
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Alshaima’a M. Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
- Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Francis J. Prael
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Krystian A. Kozek
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Vanderbilt Medical Scientist Training Program, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Roman M. Lazarenko
- Department of Anesthesiology, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Jerod S. Denton
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Anesthesiology, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - C. David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
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37
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Shore AN, Colombo S, Tobin WF, Petri S, Cullen ER, Dominguez S, Bostick CD, Beaumont MA, Williams D, Khodagholy D, Yang M, Lutz CM, Peng Y, Gelinas JN, Goldstein DB, Boland MJ, Frankel WN, Weston MC. Reduced GABAergic Neuron Excitability, Altered Synaptic Connectivity, and Seizures in a KCNT1 Gain-of-Function Mouse Model of Childhood Epilepsy. Cell Rep 2020; 33:108303. [PMID: 33113364 PMCID: PMC7712469 DOI: 10.1016/j.celrep.2020.108303] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 08/06/2020] [Accepted: 10/01/2020] [Indexed: 01/07/2023] Open
Abstract
Gain-of-function (GOF) variants in K+ channels cause severe childhood epilepsies, but there are no mechanisms to explain how increased K+ currents lead to network hyperexcitability. Here, we introduce a human Na+-activated K+ (KNa) channel variant (KCNT1-Y796H) into mice and, using a multiplatform approach, find motor cortex hyperexcitability and early-onset seizures, phenotypes strikingly similar to those of human patients. Although the variant increases KNa currents in cortical excitatory and inhibitory neurons, there is an increase in the KNa current across subthreshold voltages only in inhibitory neurons, particularly in those with non-fast-spiking properties, resulting in inhibitory-neuron-specific impairments in excitability and action potential (AP) generation. We further observe evidence of synaptic rewiring, including increases in homotypic synaptic connectivity, accompanied by network hyperexcitability and hypersynchronicity. These findings support inhibitory-neuron-specific mechanisms in mediating the epileptogenic effects of KCNT1 channel GOF, offering cell-type-specific currents and effects as promising targets for therapeutic intervention.
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Affiliation(s)
- Amy N Shore
- Department of Neurological Sciences, University of Vermont, Burlington, VT 05405, USA
| | - Sophie Colombo
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA
| | - William F Tobin
- Department of Neurological Sciences, University of Vermont, Burlington, VT 05405, USA
| | - Sabrina Petri
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA
| | - Erin R Cullen
- Department of Neurological Sciences, University of Vermont, Burlington, VT 05405, USA
| | - Soledad Dominguez
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA
| | | | - Michael A Beaumont
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA; Axion BioSystems, Atlanta, GA 30309, USA
| | - Damian Williams
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA
| | - Dion Khodagholy
- Department of Electrical Engineering, Columbia University, New York, NY 10032, USA
| | - Mu Yang
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA
| | | | - Yueqing Peng
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Jennifer N Gelinas
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA; Department of Neurology, Columbia University, New York, NY 10032, USA
| | - David B Goldstein
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA; Department of Genetics and Development, Columbia University, New York, NY 10032, USA
| | - Michael J Boland
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA; Department of Genetics and Development, Columbia University, New York, NY 10032, USA
| | - Wayne N Frankel
- Institute for Genomic Medicine, Columbia University, New York, NY 10032, USA; Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Matthew C Weston
- Department of Neurological Sciences, University of Vermont, Burlington, VT 05405, USA.
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38
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Modulation of Function, Structure and Clustering of K + Channels by Lipids: Lessons Learnt from KcsA. Int J Mol Sci 2020; 21:ijms21072554. [PMID: 32272616 PMCID: PMC7177331 DOI: 10.3390/ijms21072554] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/02/2020] [Accepted: 04/05/2020] [Indexed: 12/19/2022] Open
Abstract
KcsA, a prokaryote tetrameric potassium channel, was the first ion channel ever to be structurally solved at high resolution. This, along with the ease of its expression and purification, made KcsA an experimental system of choice to study structure–function relationships in ion channels. In fact, much of our current understanding on how the different channel families operate arises from earlier KcsA information. Being an integral membrane protein, KcsA is also an excellent model to study how lipid–protein and protein–protein interactions within membranes, modulate its activity and structure. In regard to the later, a variety of equilibrium and non-equilibrium methods have been used in a truly multidisciplinary effort to study the effects of lipids on the KcsA channel. Remarkably, both experimental and “in silico” data point to the relevance of specific lipid binding to two key arginine residues. These residues are at non-annular lipid binding sites on the protein and act as a common element to trigger many of the lipid effects on this channel. Thus, processes as different as the inactivation of channel currents or the assembly of clusters from individual KcsA channels, depend upon such lipid binding.
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39
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Impaired motor skill learning and altered seizure susceptibility in mice with loss or gain of function of the Kcnt1 gene encoding Slack (K Na1.1) Na +-activated K + channels. Sci Rep 2020; 10:3213. [PMID: 32081855 PMCID: PMC7035262 DOI: 10.1038/s41598-020-60028-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 02/03/2020] [Indexed: 12/23/2022] Open
Abstract
Gain-of-function mutations in KCNT1, the gene encoding Slack (KNa1.1) channels, result in epilepsy of infancy with migrating focal seizures (EIMFS) and several other forms of epilepsy associated with severe intellectual disability. We have generated a mouse model of this condition by replacing the wild type gene with one encoding Kcnt1R455H, a cytoplasmic C-terminal mutation homologous to a human R474H variant that results in EIMFS. We compared behavior patterns and seizure activity in these mice with those of wild type mice and Kcnt1-/- mice. Complete loss of Kcnt1 produced deficits in open field behavior and motor skill learning. Although their thresholds for electrically and chemically induced seizures were similar to those of wild type animals, Kcnt1-/- mice were significantly protected from death after maximum electroshock-induced seizures. In contrast, homozygous Kcnt1R455H/R455H mice were embryonic lethal. Video-EEG monitoring of heterozygous Kcnt1+/R455H animals revealed persistent interictal spikes, spontaneous seizures and a substantially decreased threshold for pentylenetetrazole-induced seizures. Surprisingly, Kcnt1+/R455H mice were not impaired in tasks of exploratory behavior or procedural motor learning. These findings provide an animal model for EIMFS and suggest that Slack channels are required for the development of procedural learning and of pathways that link cortical seizures to other regions required for animal survival.
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40
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Pfeiffer P, Egorov AV, Lorenz F, Schleimer JH, Draguhn A, Schreiber S. Clusters of cooperative ion channels enable a membrane-potential-based mechanism for short-term memory. eLife 2020; 9:49974. [PMID: 32031523 PMCID: PMC7007218 DOI: 10.7554/elife.49974] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 01/14/2020] [Indexed: 12/11/2022] Open
Abstract
Across biological systems, cooperativity between proteins enables fast actions, supra-linear responses, and long-lasting molecular switches. In the nervous system, however, the function of cooperative interactions between voltage-dependent ionic channels remains largely unknown. Based on mathematical modeling, we here demonstrate that clusters of strongly cooperative ion channels can plausibly form bistable conductances. Consequently, clusters are permanently switched on by neuronal spiking, switched off by strong hyperpolarization, and remain in their state for seconds after stimulation. The resulting short-term memory of the membrane potential allows to generate persistent firing when clusters of cooperative channels are present together with non-cooperative spike-generating conductances. Dynamic clamp experiments in rodent cortical neurons confirm that channel cooperativity can robustly induce graded persistent activity - a single-cell based, multistable mnemonic firing mode experimentally observed in several brain regions. We therefore propose that ion channel cooperativity constitutes an efficient cell-intrinsic implementation for short-term memories at the voltage level.
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Affiliation(s)
- Paul Pfeiffer
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany.,Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Alexei V Egorov
- Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Franziska Lorenz
- Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Jan-Hendrik Schleimer
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany.,Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Susanne Schreiber
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany.,Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin, Germany
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41
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Ali SR, Malone TJ, Zhang Y, Prechova M, Kaczmarek LK. Phactr1 regulates Slack (KCNT1) channels via protein phosphatase 1 (PP1). FASEB J 2020; 34:1591-1601. [PMID: 31914597 PMCID: PMC6956700 DOI: 10.1096/fj.201902366r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 12/14/2022]
Abstract
The Slack (KCNT1) gene encodes sodium-activated potassium channels that are abundantly expressed in the central nervous system. Human mutations alter the function of Slack channels, resulting in epilepsy and intellectual disability. Most of the disease-causing mutations are located in the extended cytoplasmic C-terminus of Slack channels and result in increased Slack current. Previous experiments have shown that the C-terminus of Slack channels binds a number of cytoplasmic signaling proteins. One of these is Phactr1, an actin-binding protein that recruits protein phosphatase 1 (PP1) to certain phosphoprotein substrates. Using co-immunoprecipitation, we found that Phactr1 is required to link the channels to actin. Using patch clamp recordings, we found that co-expression of Phactr1 with wild-type Slack channels reduces the current amplitude but has no effect on Slack channels in which a conserved PKC phosphorylation site (S407) that regulates the current amplitude has been mutated. Furthermore, a Phactr1 mutant that disrupts the binding of PP1 but not that of actin fails to alter Slack currents. Our data suggest that Phactr1 regulates the Slack by linking PP1 to the channel. Targeting Slack-Phactr1 interactions may therefore be helpful in developing the novel therapies for brain disorders associated with the malfunction of Slack channels.
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Affiliation(s)
- Syed Rydwan Ali
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA
| | | | - Yalan Zhang
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA
| | - Magdalena Prechova
- Signalling and Transcription Group, The Francis Crick Institute, London, UK
- Laboratory of Integrative Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, CZ
| | - Leonard Konrad Kaczmarek
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
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Abstract
The new concept of developmental and epileptic encephalopathy is based on the understanding that many genetic epilepsies are associated with developmental impairment as a direct consequence of the genetic mutation, in addition to the effect of the frequent epileptic activity on brain development. As an example, in infants with KCNQ2 or STXBP1 encephalopathy, seizures may be controlled early after onset or cease spontaneously after a few years, but the developmental consequences tend to remain profound. The term "developmental and epileptic encephalopathy" expresses the concept that the genetic defect may be responsible for both the epilepsy and adverse development which is crucial to understanding the disease process for both families and clinicians. The increased use of EEG monitoring, neuroimaging, and metabolic and genetic testing in the Neonatal Intensive Care Unit has greatly improved our understanding of neonatal-onset epilepsies as seen with the syndromes Ohtahara and Early Myoclonic Encephalopathy outlined in the 1970s into distinct etiology-specific electroclinical phenotypes.
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Affiliation(s)
- Charbel El Kosseifi
- Catholic University of Louvain, Cliniques Universitaires Saint Luc, Brussels, Belgium
| | | | - Maria Roberta Cilio
- Division of Pediatric Neurology, Saint-Luc University Hospital, and Institute of Experimental and Clinical Research (IREC), University of Louvain, Brussels, Belgium.
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Barcia G, Chemaly N, Kuchenbuch M, Eisermann M, Gobin-Limballe S, Ciorna V, Macaya A, Lambert L, Dubois F, Doummar D, Billette de Villemeur T, Villeneuve N, Barthez MA, Nava C, Boddaert N, Kaminska A, Bahi-Buisson N, Milh M, Auvin S, Bonnefont JP, Nabbout R. Epilepsy with migrating focal seizures: KCNT1 mutation hotspots and phenotype variability. NEUROLOGY-GENETICS 2019; 5:e363. [PMID: 31872048 PMCID: PMC6878841 DOI: 10.1212/nxg.0000000000000363] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 09/04/2019] [Indexed: 01/29/2023]
Abstract
Objective To report new sporadic cases and 1 family with epilepsy of infancy with migrating focal seizures (EIMFSs) due to KCNT1 gain-of-function and to assess therapies' efficacy including quinidine. Methods We reviewed the clinical, EEG, and molecular data of 17 new patients with EIMFS and KCNT1 mutations, in collaboration with the network of the French reference center for rare epilepsies. Results The mean seizure onset age was 1 month (range: 1 hour to 4 months), and all children had focal motor seizures with autonomic signs and migrating ictal pattern on EEG. Three children also had infantile spasms and hypsarrhythmia. The identified KCNT1 variants clustered as “hot spots” on the C-terminal domain, and all mutations occurred de novo except the p.R398Q mutation inherited from the father with nocturnal frontal lobe epilepsy, present in 2 paternal uncles, one being asymptomatic and the other with single tonic-clonic seizure. In 1 patient with EIMFS, we identified the p.R1106Q mutation associated with Brugada syndrome and saw no abnormality in cardiac rhythm. Quinidine was well tolerated when administered to 2 and 4-year-old patients but did not reduce seizure frequency. Conclusions The majority of the KCNT1 mutations appear to cluster in hot spots essential for the channel activity. A same mutation can be linked to a spectrum of conditions ranging from EMFSI to asymptomatic carrier, even in the same family. None of the antiepileptic therapies displayed clinical efficacy, including quinidine in 2 patients.
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Affiliation(s)
- Giulia Barcia
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Nicole Chemaly
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Mathieu Kuchenbuch
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Monika Eisermann
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Stéphanie Gobin-Limballe
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Viorica Ciorna
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Alfons Macaya
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Laetitia Lambert
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Fanny Dubois
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Diane Doummar
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Thierry Billette de Villemeur
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Nathalie Villeneuve
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Marie-Anne Barthez
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Caroline Nava
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Nathalie Boddaert
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Anna Kaminska
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Nadia Bahi-Buisson
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Mathieu Milh
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Stéphane Auvin
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Jean-Paul Bonnefont
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Rima Nabbout
- Service de Génétique (G.B., J.-P.B., S.G.-L.), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1163 (G.B., N.B-.B., R.N.), Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, France; Service de Neurologie Pédiatrique (N.C., N.B-.B., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Centre de Référence des Epilepsies Rares (N.C., A.K., R.N.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM U1129 (N.N., A.K., R.N.), Paris, France; Service de Neurophysiologie Clinique et Pédiatrie (M.K.), INSERM U1099, Hôpital Universitaire de Rennes, Université de Rennes, France; Service de Neurophysiologie Clinique (M.E., A.K.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Génétique Clinique (V.C.), Hôpital Femme Mère Enfant, Metz-Thionville, France; Pediatric Neurology Research Group (A.M.), Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Service de Génétique Clinique (L.L.), Hôpital d'Enfants, CHU de Nancy, Vandoeuvre-Lès-Nancy, France; Service de Pédiatrie (F.D.), CHU de Grenoble, France; Service de Neurologie Pédiatrique (D.D., T.B.V.), Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Neurologie Pédiatrique (N.V., M.M.), APHM, Hôpital d'Enfants de La Timone, Marseille, France; Service de Neurologie Pédiatrique (M-.A.B., M.M.), Centre Hospitalier Universitaire de Tours, Tours, France; Département de Génétique (C.N., M.M.), Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France; Service de Radiologie Pédiatrique (N.B., M.M.), Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France; Université Aix-Marseille (M.M.), INSERM, MMG, UMR-S 1251, Faculté de Médecine, Marseille, France; and Unité de Neurologie Pédiatrique (S.A.), Hôpital Rober Debré, Assistance Publique-Hôpitaux de Paris, Paris, France
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Datta AN, Michoulas A, Guella I, Demos M. Two Patients With KCNT1-Related Epilepsy Responding to Phenobarbital and Potassium Bromide. J Child Neurol 2019; 34:728-734. [PMID: 31208268 DOI: 10.1177/0883073819854853] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
KCNT1 encodes a sodium-activated potassium channel highly expressed in the brain, regulating hyperpolarization following repetitive firing. Mutations in KCNT1 were originally implicated in autosomal-dominant nocturnal frontal lobe epilepsy and epilepsy of infancy with migrating focal seizures. It is now known that there is variability in phenotypic expression and incomplete penetrance. We describe 2 patients with KCNT1-related epilepsy, one with epilepsy of infancy with migrating focal seizures and one with multifocal epilepsy. As most patients with KCNT1 variants have treatment-resistant epilepsy, drugs that specifically target the KCNT1 channel have been of great interest. Quinidine, a broad-spectrum potassium channel blocker, has shown promise; however, clinical trial results have been variable. Our patient with epilepsy of infancy with migrating focal seizures did not respond to a trial of quinidine at 6 weeks of age-one of the earliest reported quinidine trials in the literature for KCNT1-related epilepsy. This indicates that timing of treatment and response may not be related. Both patients responded to high-dose phenobarbital. The patient with epilepsy of infancy with migrating focal seizures also had a significant reduction in seizures with potassium bromide (KBr). Our data suggest that alternative therapies to quinidine should be considered as a therapeutic option for patients with KCNT1-related epilepsy. Although improved seizure control led to parent-reported improvements in neurodevelopment, it is unknown if phenobarbital and KBr impact the overall developmental trajectory of patients with KCNT1-related epilepsy. Further multicenter longitudinal studies are required.
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Affiliation(s)
- Anita N Datta
- 1 Division of Pediatric Neurology, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aspasia Michoulas
- 1 Division of Pediatric Neurology, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ilaria Guella
- 2 Centre for Applied Neurogenetics, University of British Columbia, Vancouver, British Columbia, Canada
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- 3 University of British Columbia, Vancouver, British Columbia, Canada.,EPGEN Study investigators include Shelin Adam, Cyrus Boelman, Corneliu Bolbocean, Sarah E. Buerki, Tara Candido, Patrice Eydoux, Daniel M. Evans, William Gibson, Gabriella Horvath, Linda Huh, Tanya N. Nelson, Graham Sinclair, Tamsin Tarling, Eric B. Toyota, Katelin N. Townsend, Margot I. Van Allen, Clara van Karnebeek, and Suzanne Vercauteren
| | - Michelle Demos
- 1 Division of Pediatric Neurology, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
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Abstract
Axons functionally link the somato-dendritic compartment to synaptic terminals. Structurally and functionally diverse, they accomplish a central role in determining the delays and reliability with which neuronal ensembles communicate. By combining their active and passive biophysical properties, they ensure a plethora of physiological computations. In this review, we revisit the biophysics of generation and propagation of electrical signals in the axon and their dynamics. We further place the computational abilities of axons in the context of intracellular and intercellular coupling. We discuss how, by means of sophisticated biophysical mechanisms, axons expand the repertoire of axonal computation, and thereby, of neural computation.
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Affiliation(s)
- Pepe Alcami
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet Muenchen, Martinsried, Germany
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany
| | - Ahmed El Hady
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, United States
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ, United States
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46
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Gataullina S, Bienvenu T, Nabbout R, Huberfeld G, Dulac O. Gene mutations in paediatric epilepsies cause NMDA-pathy, and phasic and tonic GABA-pathy. Dev Med Child Neurol 2019; 61:891-898. [PMID: 30680721 DOI: 10.1111/dmcn.14152] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/20/2018] [Indexed: 12/28/2022]
Abstract
The aim of this study was to disentangle mechanisms of epileptogenesis in monogenic epilepsies in children. We reviewed paediatric monogenic epilepsies excluding brain malformation or an inborn error of metabolism, but including the gene function whether there is loss-of-function or gain-of-function, age at gene expression when available, and associated epilepsy syndrome. Genes for which at least five patients with similar epilepsy phenotype had been reported were selected. Three mechanisms are shared by most monogenic epilepsies: (1) excess of N-methyl-d-aspartate (NMDA) transmission activation (NMDA-pathies); (2) abnormal gamma-aminobutyric acid (GABA) transmission with reduced inhibition (phasic GABA-pathies); and (3) tonic activation of extrasynaptic GABAA receptors by extracellular GABA (tonic GABA-pathies). NMDA-pathies comprise early epileptic encephalopathy with suppression-burst, neonatal/infantile benign seizures, West and Lennox-Gastaut syndromes, and encephalopathy with continuous spike waves in slow sleep, thus brief seizures with major interictal spiking. Phasic GABA-pathies comprise mostly generalized epilepsy with febrile seizures plus and Dravet syndrome, thus long-lasting seizures with mild interictal spiking. Tonic GABA-pathies cause epilepsy with myoclonic-atonic seizures and Angelman syndrome, thus major high-amplitude slow-wave activity. This pathophysiological approach to monogenic epilepsies provides diagnostic clues and helps to guide treatment strategy. WHAT THIS PAPER ADDS: In paediatric monogenic epilepsies, electroclinical patterns point to three main mechanisms: NMDA-pathies, and phasic and tonic GABA-pathies. Antiepileptic treatment choice could be guided by each of these mechanisms.
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Affiliation(s)
- Svetlana Gataullina
- Service d' Explorations Fonctionnelles multidisciplinaires Hôpital Antoine Béclère, AP-HP, Clamart, France.,Inserm U1129, Infantile Epilepsies and Brain Plasticity, CEA Gif/Yvette, Pôle de Recherche et d'Enseignement Supérieur Sorbonne Paris Cité, Paris Descartes University, Paris, France.,Service de Pédiatrie, Centre Hospitalier Intercommunal, Montreuil, France
| | - Thierry Bienvenu
- Biochemistry and Molecular Genetics Laboratory, Hôpital Cochin, Paris Centre University Group, Paris, France.,Institut Cochin, Inserm U1016, Paris Descartes University, Paris, France
| | - Rima Nabbout
- Centre de Reference Épilepsies Rares, Necker-Enfants Malades Hospital, Paris, France
| | - Gilles Huberfeld
- Inserm U1129, Infantile Epilepsies and Brain Plasticity, CEA Gif/Yvette, Pôle de Recherche et d'Enseignement Supérieur Sorbonne Paris Cité, Paris Descartes University, Paris, France.,Clinical Neurophysiology Department, Pitié-Salpêtrière Hospital, Sorbone University, AP-HP, Paris, France.,Neuroglial Interactions in Cerebral Pathophysiology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7421, Inserm U1050, Labex MemolifePSL Research University, Paris, France
| | - Olivier Dulac
- Inserm U1129, Infantile Epilepsies and Brain Plasticity, CEA Gif/Yvette, Pôle de Recherche et d'Enseignement Supérieur Sorbonne Paris Cité, Paris Descartes University, Paris, France.,AdPueriVitam, Antony, France
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An Epilepsy-Associated KCNT1 Mutation Enhances Excitability of Human iPSC-Derived Neurons by Increasing Slack K Na Currents. J Neurosci 2019; 39:7438-7449. [PMID: 31350261 DOI: 10.1523/jneurosci.1628-18.2019] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 07/08/2019] [Accepted: 07/17/2019] [Indexed: 12/26/2022] Open
Abstract
Mutations in the KCNT1 (Slack, KNa1.1) sodium-activated potassium channel produce severe epileptic encephalopathies. Expression in heterologous systems has shown that the disease-causing mutations give rise to channels that have increased current amplitude. It is not known, however, whether such gain of function occurs in human neurons, nor whether such increased KNa current is expected to suppress or increase the excitability of cortical neurons. Using genetically engineered human induced pluripotent stem cell (iPSC)-derived neurons, we have now found that sodium-dependent potassium currents are increased several-fold in neurons bearing a homozygous P924L mutation. In current-clamp recordings, the increased KNa current in neurons with the P924L mutation acts to shorten the duration of action potentials and to increase the amplitude of the afterhyperpolarization that follows each action potential. Strikingly, the number of action potentials that were evoked by depolarizing currents as well as maximal firing rates were increased in neurons expressing the mutant channel. In networks of spontaneously active neurons, the mean firing rate, the occurrence of rapid bursts of action potentials, and the intensity of firing during the burst were all increased in neurons with the P924L Slack mutation. The feasibility of an increased KNa current to increase firing rates independent of any compensatory changes was validated by numerical simulations. Our findings indicate that gain-of-function in Slack KNa channels causes hyperexcitability in both isolated neurons and in neural networks and occurs by a cell-autonomous mechanism that does not require network interactions.SIGNIFICANCE STATEMENT KCNT1 mutations lead to severe epileptic encephalopathies for which there are no effective treatments. This study is the first demonstration that a KCNT1 mutation increases the Slack current in neurons. It also provides the first explanation for how this increased potassium current induces hyperexcitability, which could be the underlining factor causing seizures.
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Bisulli F, Licchetta L, Tinuper P. Sleep related hyper motor epilepsy (SHE): a unique syndrome with heterogeneous genetic etiologies. SLEEP SCIENCE AND PRACTICE 2019. [DOI: 10.1186/s41606-019-0035-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Hamada N, Ogaya S, Nakashima M, Nishijo T, Sugawara Y, Iwamoto I, Ito H, Maki Y, Shirai K, Baba S, Maruyama K, Saitsu H, Kato M, Matsumoto N, Momiyama T, Nagata KI. De novo PHACTR1 mutations in West syndrome and their pathophysiological effects. Brain 2019; 141:3098-3114. [PMID: 30256902 DOI: 10.1093/brain/awy246] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 08/02/2018] [Indexed: 12/11/2022] Open
Abstract
Trio-based whole exome sequencing identified two de novo heterozygous missense mutations [c.1449T > C/p.(Leu500Pro) and c.1436A > T/p.(Asn479Ile)] in PHACTR1, encoding a molecule critical for the regulation of protein phosphatase 1 (PP1) and the actin cytoskeleton, in unrelated Japanese individuals with West syndrome (infantile spasms with intellectual disability). We then examined the role of Phactr1 in the development of mouse cerebral cortex and the pathophysiological significance of these two mutations and others [c.1561C > T/p.(Arg521Cys) and c.1553T > A/p.(Ile518Asn)], which had been reported in undiagnosed patients with intellectual disability. Immunoprecipitation analyses revealed that actin-binding activity of PHACTR1 was impaired by the p.Leu500Pro, p.Asn479Ile and p.Ile518Asn mutations while the p.Arg521Cys mutation exhibited impaired binding to PP1. Acute knockdown of mouse Phactr1 using in utero electroporation caused defects in cortical neuron migration during corticogenesis, which were rescued by an RNAi-resistant PHACTR1 but not by the four mutants. Experiments using knockdown combined with expression mutants, aimed to mimic the effects of the heterozygous mutations under conditions of haploinsufficiency, suggested a dominant negative effect of the mutant allele. As for dendritic development in vivo, only the p.Arg521Cys mutant was determined to have dominant negative effects, because the three other mutants appeared to be degraded with these experimental conditions. Electrophysiological analyses revealed abnormal synaptic properties in Phactr1-deficient excitatory cortical neurons. Our data show that the PHACTR1 mutations may cause morphological and functional defects in cortical neurons during brain development, which is likely to be related to the pathophysiology of West syndrome and other neurodevelopmental disorders.
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Affiliation(s)
- Nanako Hamada
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan.,Research Fellow of Japan Society for the Promotion of Science, Japan
| | - Shunsuke Ogaya
- Department of Pediatric Neurology, Central Hospital, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Mitsuko Nakashima
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan
| | - Takuma Nishijo
- Department of Pharmacology, Jikei University School of Medicine, 3-19-18 Nishishimbashi, Minato-ku, Tokyo, Japan
| | - Yuji Sugawara
- Department of Pediatrics, Soka Municipal Hospital, 2-21-1 Soka, Soka, Saitama, Japan
| | - Ikuko Iwamoto
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Hidenori Ito
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Yuki Maki
- Department of Pediatric Neurology, Central Hospital, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Kentaro Shirai
- Department of Pediatrics, Tsuchiura Kyodo Hospital, 4-1-1 Ootsuno, Tsuchiura, Ibaraki, Japan
| | - Shimpei Baba
- Department of Child Neurology, Comprehensive Epilepsy Center, Seirei-Hamamatsu General Hospital, 2-12-12 Sumiyoshi, Naka-ku, Hamamatsu, Shizuoka, Japan
| | - Koichi Maruyama
- Department of Pediatric Neurology, Central Hospital, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan
| | - Toshihiko Momiyama
- Department of Pharmacology, Jikei University School of Medicine, 3-19-18 Nishishimbashi, Minato-ku, Tokyo, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan.,Department of Neurochemistry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, Japan
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50
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Gertler TS, Thompson CH, Vanoye CG, Millichap JJ, George AL. Functional consequences of a KCNT1 variant associated with status dystonicus and early-onset infantile encephalopathy. Ann Clin Transl Neurol 2019; 6:1606-1615. [PMID: 31560846 PMCID: PMC6764634 DOI: 10.1002/acn3.50847] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/13/2022] Open
Abstract
Objective We identified a novel de novo KCNT1 variant in a patient with early‐infantile epileptic encephalopathy (EIEE) and status dystonicus, a life‐threatening movement disorder. We determined the functional consequences of this variant on the encoded KNa1.1 channel to investigate the molecular mechanisms responsible for this disorder. Methods A retrospective case review of the proband is presented. We performed manual and automated electrophysiologic analyses of the KCNT1‐L437F variant expressed heterologously in Chinese hamster ovary (CHO) cells in the presence of channel activators/blockers. Results The KCNT1‐L437F variant, identified in a patient with refractory EIEE and status dystonicus, confers a gain‐of‐function channel phenotype characterized by instantaneous, voltage‐dependent activation. Channel openers do not further increase L437F channel function, suggesting maximal activation, whereas channel blockers similarly block wild‐type and variant channels. We further demonstrated that KCNT1 current can be measured on a high‐throughput automated electrophysiology platform with potential value for future screening of novel and repurposed pharmacotherapies. Interpretation A novel pathogenic variant in KCNT1 associated with early‐onset, medication‐refractory epilepsy and dystonia causes gain‐of‐function with rapid activation kinetics. Our findings extend the genotype–phenotype relationships of KCNT1 variants to include severe dystonia.
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Affiliation(s)
- Tracy S Gertler
- Division of Neurology, Department of Pediatrics, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.,Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Carlos G Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - John J Millichap
- Division of Neurology, Department of Pediatrics, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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