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Currie D, Wong N, Zane I, Rix T, Vardakastanis M, Claxton A, Ong KKV, Macmorland W, Poivet A, Brooks A, Niola P, Huntley D, Montano X. A Potential Prognostic Gene Signature Associated with p53-Dependent NTRK1 Activation and Increased Survival of Neuroblastoma Patients. Cancers (Basel) 2024; 16:722. [PMID: 38398114 PMCID: PMC10886603 DOI: 10.3390/cancers16040722] [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: 12/28/2023] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Neuroblastoma is the most common extracranial solid tumour in children, comprising close to 10% of childhood cancer-related deaths. We have demonstrated that activation of NTRK1 by TP53 repression of PTPN6 expression is significantly associated with favourable survival in neuroblastoma. The molecular mechanisms by which this activation elicits cell molecular changes need to be determined. This is critical to identify dependable biomarkers for the early detection and prognosis of tumours, and for the development of personalised treatment. In this investigation we have identified and validated a gene signature for the prognosis of neuroblastoma using genes differentially expressed upon activation of the NTRK1-PTPN6-TP53 module. A random survival forest model was used to construct a gene signature, which was then assessed across validation datasets using Kaplan-Meier analysis and ROC curves. The analysis demonstrated that high BASP1, CD9, DLG2, FNBP1, FRMD3, IL11RA, ISGF10, IQCE, KCNQ3, and TOX2, and low BSG/CD147, CCDC125, GABRB3, GNB2L1/RACK1 HAPLN4, HEBP2, and HSD17B12 expression was significantly associated with favourable patient event-free survival (EFS). The gene signature was associated with favourable tumour histology and NTRK1-PTPN6-TP53 module activation. Importantly, all genes were significantly associated with favourable EFS in an independent manner. Six of the signature genes, BSG/CD147, GNB2L1/RACK1, TXNDC5, FNPB1, B3GAT1, and IGSF10, play a role in cell differentiation. Our findings strongly suggest that the identified gene signature is a potential prognostic biomarker and therapeutic target for neuroblastoma patients and that it is associated with neuroblastoma cell differentiation through the activation of the NTRK1-PTPN6-TP53 module.
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Affiliation(s)
- David Currie
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; (D.C.); (N.W.); (I.Z.); (T.R.); (M.V.); (A.P.); (D.H.)
| | - Nicole Wong
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; (D.C.); (N.W.); (I.Z.); (T.R.); (M.V.); (A.P.); (D.H.)
| | - Isabelle Zane
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; (D.C.); (N.W.); (I.Z.); (T.R.); (M.V.); (A.P.); (D.H.)
| | - Tom Rix
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; (D.C.); (N.W.); (I.Z.); (T.R.); (M.V.); (A.P.); (D.H.)
| | - Marios Vardakastanis
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; (D.C.); (N.W.); (I.Z.); (T.R.); (M.V.); (A.P.); (D.H.)
| | - Amelia Claxton
- Innovation Hub, Comprehensive Cancer Centre, King’s College London, Great Maze Pond, London SE1 9RT, UK; (A.C.); (K.K.V.O.)
| | - Karine K. V. Ong
- Innovation Hub, Comprehensive Cancer Centre, King’s College London, Great Maze Pond, London SE1 9RT, UK; (A.C.); (K.K.V.O.)
| | - William Macmorland
- Tumour Immunology Group, School of Cancer and Pharmaceutical Sciences, King’s College London, London SE1 1UL, UK;
| | - Arthur Poivet
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; (D.C.); (N.W.); (I.Z.); (T.R.); (M.V.); (A.P.); (D.H.)
| | - Anthony Brooks
- Zayed Centre for Research into Rare Disease in Children, UCL Genomics, London WC1N 1DZ, UK;
| | | | - Derek Huntley
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; (D.C.); (N.W.); (I.Z.); (T.R.); (M.V.); (A.P.); (D.H.)
| | - Ximena Montano
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; (D.C.); (N.W.); (I.Z.); (T.R.); (M.V.); (A.P.); (D.H.)
- Innovation Hub, Comprehensive Cancer Centre, King’s College London, Great Maze Pond, London SE1 9RT, UK; (A.C.); (K.K.V.O.)
- School of Life Sciences, University of Westminster, London W1W 6UW, UK
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Millevert C, Weckhuysen S. ILAE Genetic Literacy Series: Self-limited familial epilepsy syndromes with onset in neonatal age and infancy. Epileptic Disord 2023; 25:445-453. [PMID: 36939707 DOI: 10.1002/epd2.20026] [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: 10/10/2022] [Revised: 12/13/2022] [Accepted: 12/22/2022] [Indexed: 03/21/2023]
Abstract
The self-limited (familial) epilepsies with onset in neonates or infants, formerly called benign familial neonatal and/or infantile epilepsies, are autosomal dominant disorders characterized by neonatal- or infantile-onset focal motor seizures and the absence of neurodevelopmental complications. Seizures tend to remit during infancy or early childhood and are therefore called "self-limited". A positive family history for epilepsy usually suggests the genetic etiology, but incomplete penetrance and de novo inheritance occur. Here, we review the phenotypic spectrum and the genetic architecture of self-limited (familial) epilepsies with onset in neonates or infants. Using an illustrative case study, we describe important clues in recognition of these syndromes, diagnostic steps including genetic testing, management, and genetic counseling.
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Affiliation(s)
- Charissa Millevert
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium
- Department of Neurology, University Hospital, Antwerp, Belgium
| | - Sarah Weckhuysen
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium
- Department of Neurology, University Hospital, Antwerp, Belgium
- μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium
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3
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Hou B, Santaniello S, Tzingounis AV. KCNQ2 channels regulate the population activity of neonatal GABAergic neurons ex vivo. Front Neurol 2023; 14:1207539. [PMID: 37409016 PMCID: PMC10318362 DOI: 10.3389/fneur.2023.1207539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 05/18/2023] [Indexed: 07/07/2023] Open
Abstract
Over the last decade KCNQ2 channels have arisen as fundamental and indispensable regulators of neonatal brain excitability, with KCNQ2 loss-of-function pathogenic variants being increasingly identified in patients with developmental and epileptic encephalopathy. However, the mechanisms by which KCNQ2 loss-of-function variants lead to network dysfunction are not fully known. An important remaining knowledge gap is whether loss of KCNQ2 function alters GABAergic interneuron activity early in development. To address this question, we applied mesoscale calcium imaging ex vivo in postnatal day 4-7 mice lacking KCNQ2 channels in interneurons (Vgat-ires-cre;Kcnq2f/f;GCamp5). In the presence of elevated extracellular potassium concentrations, ablation of KCNQ2 channels from GABAergic cells increased the interneuron population activity in the hippocampal formation and regions of the neocortex. We found that this increased population activity depends on fast synaptic transmission, with excitatory transmission promoting the activity and GABAergic transmission curtailing it. Together, our data show that loss of function of KCNQ2 channels from interneurons increases the network excitability of the immature GABAergic circuits, revealing a new function of KCNQ2 channels in interneuron physiology in the developing brain.
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Affiliation(s)
- Bowen Hou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Sabato Santaniello
- Department of Biomedical Engineering and CT Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, United States
| | - Anastasios V. Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
- Department of Biomedical Engineering and CT Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, United States
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4
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Marafi D, Kozar N, Duan R, Bradley S, Yokochi K, Al Mutairi F, Saadi NW, Whalen S, Brunet T, Kotzaeridou U, Choukair D, Keren B, Nava C, Kato M, Arai H, Froukh T, Faqeih EA, AlAsmari AM, Saleh MM, Pinto e Vairo F, Pichurin PN, Klee EW, Schmitz CT, Grochowski CM, Mitani T, Herman I, Calame DG, Fatih JM, Du H, Coban-Akdemir Z, Pehlivan D, Jhangiani SN, Gibbs RA, Miyatake S, Matsumoto N, Wagstaff LJ, Posey JE, Lupski JR, Meijer D, Wagner M. A reverse genetics and genomics approach to gene paralog function and disease: Myokymia and the juxtaparanode. Am J Hum Genet 2022; 109:1713-1723. [PMID: 35948005 PMCID: PMC9502070 DOI: 10.1016/j.ajhg.2022.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022] Open
Abstract
The leucine-rich glioma-inactivated (LGI) family consists of four highly conserved paralogous genes, LGI1-4, that are highly expressed in mammalian central and/or peripheral nervous systems. LGI1 antibodies are detected in subjects with autoimmune limbic encephalitis and peripheral nerve hyperexcitability syndromes (PNHSs) such as Isaacs and Morvan syndromes. Pathogenic variations of LGI1 and LGI4 are associated with neurological disorders as disease traits including familial temporal lobe epilepsy and neurogenic arthrogryposis multiplex congenita 1 with myelin defects, respectively. No human disease has been reported associated with either LGI2 or LGI3. We implemented exome sequencing and family-based genomics to identify individuals with deleterious variants in LGI3 and utilized GeneMatcher to connect practitioners and researchers worldwide to investigate the clinical and electrophysiological phenotype in affected subjects. We also generated Lgi3-null mice and performed peripheral nerve dissection and immunohistochemistry to examine the juxtaparanode LGI3 microarchitecture. As a result, we identified 16 individuals from eight unrelated families with loss-of-function (LoF) bi-allelic variants in LGI3. Deep phenotypic characterization showed LGI3 LoF causes a potentially clinically recognizable PNHS trait characterized by global developmental delay, intellectual disability, distal deformities with diminished reflexes, visible facial myokymia, and distinctive electromyographic features suggestive of motor nerve instability. Lgi3-null mice showed reduced and mis-localized Kv1 channel complexes in myelinated peripheral axons. Our data demonstrate bi-allelic LoF variants in LGI3 cause a clinically distinguishable disease trait of PNHS, most likely caused by disturbed Kv1 channel distribution in the absence of LGI3.
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Affiliation(s)
- Dana Marafi
- Department of Pediatrics, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nina Kozar
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Ruizhi Duan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Stephen Bradley
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Kenji Yokochi
- Department of Pediatrics, Toyohashi Municipal Hospital, Toyohashi, Aichi 441-8570, Japan,Department of Pediatrics, Seirei Mikatahara General Hospital, Shizuoka 433-8558, Japan
| | - Fuad Al Mutairi
- Genetics and Precision Medicine Department, King Abdullah Specialized Children’s Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, P.O. Box 22490, Riyadh 11426, Kingdom of Saudi Arabia,King Abdullah International Research Center, King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Nebal Waill Saadi
- College of Medicine, University of Baghdad, Baghdad 10001, Iraq,Children Welfare Teaching Hospital, Medical City Complex, Baghdad 10001, Iraq
| | - Sandra Whalen
- UF de Génétique Clinique et Centre de Reference Anomalies du Développement et Syndromes Malformatifs, APHP, Sorbonne Université, Hôpital Trousseau, 75005 Paris, France
| | - Theresa Brunet
- Institute of Human Genetics, Faculty of Medicine, Technical University Munich, Munich, Germany,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Urania Kotzaeridou
- Division of Child Neurology and Inherited Metabolic Diseases, Centre for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Daniela Choukair
- Division of Pediatric Endocrinology, Centre for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Boris Keren
- Département de Génétique, Hôpital Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Paris 75013, France
| | - Caroline Nava
- Département de Génétique, Hôpital Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Paris 75013, France
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo 142-8666, Japan
| | - Hiroshi Arai
- Department of Pediatric Neurology, Bobath Memorial Hospital, Osaka 536-0023, Japan
| | - Tawfiq Froukh
- Department of Biotechnology and Genetic Engineering, Philadelphia University, Amman, Jordan
| | - Eissa Ali Faqeih
- Section of Medical Genetics, King Fahad Medical City, Children’s Specialist Hospital, Riyadh, Saudi Arabia
| | - Ali M. AlAsmari
- Section of Medical Genetics, King Fahad Medical City, Children’s Specialist Hospital, Riyadh, Saudi Arabia
| | - Mohammed M. Saleh
- Section of Medical Genetics, King Fahad Medical City, Children’s Specialist Hospital, Riyadh, Saudi Arabia
| | - Filippo Pinto e Vairo
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | | | - Eric W. Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA,Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | | | | | - Tadahiro Mitani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Isabella Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA,Texas Children’s Hospital, Houston, TX 77030, USA
| | - Daniel G. Calame
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA,Texas Children’s Hospital, Houston, TX 77030, USA
| | - Jawid M. Fatih
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Haowei Du
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA,Texas Children’s Hospital, Houston, TX 77030, USA
| | - Shalini N. Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Richard A. Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan,Clinical Genetics Department, Yokohama City University Hospital, Yokohama, Kanagawa 236-0004, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan
| | - Laura J. Wagstaff
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, UK
| | - Jennifer E. Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Texas Children’s Hospital, Houston, TX 77030, USA,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA,Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA,Corresponding author
| | - Dies Meijer
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
| | - Matias Wagner
- Institute for Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany,Institute of Human Genetics, Technical University Munich, Munich, Germany
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5
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Miceli F, Millevert C, Soldovieri MV, Mosca I, Ambrosino P, Carotenuto L, Schrader D, Lee HK, Riviello J, Hong W, Risen S, Emrick L, Amin H, Ville D, Edery P, de Bellescize J, Michaud V, Van-Gils J, Goizet C, Willemsen MH, Kleefstra T, Møller RS, Bayat A, Devinsky O, Sands T, Korenke GC, Kluger G, Mefford HC, Brilstra E, Lesca G, Milh M, Cooper EC, Taglialatela M, Weckhuysen S. KCNQ2 R144 variants cause neurodevelopmental disability with language impairment and autistic features without neonatal seizures through a gain-of-function mechanism. EBioMedicine 2022; 81:104130. [PMID: 35780567 PMCID: PMC9254340 DOI: 10.1016/j.ebiom.2022.104130] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 01/10/2023] Open
Abstract
Background Prior studies have revealed remarkable phenotypic heterogeneity in KCNQ2-related disorders, correlated with effects on biophysical features of heterologously expressed channels. Here, we assessed phenotypes and functional properties associated with KCNQ2 missense variants R144W, R144Q, and R144G. We also explored in vitro blockade of channels carrying R144Q mutant subunits by amitriptyline. Methods Patients were identified using the RIKEE database and through clinical collaborators. Phenotypes were collected by a standardized questionnaire. Functional and pharmacological properties of variant subunits were analyzed by whole-cell patch-clamp recordings. Findings Detailed clinical information on fifteen patients (14 novel and 1 previously published) was analyzed. All patients had developmental delay with prominent language impairment. R144Q patients were more severely affected than R144W patients. Infantile to childhood onset epilepsy occurred in 40%, while 67% of sleep-EEGs showed sleep-activated epileptiform activity. Ten patients (67%) showed autistic features. Activation gating of homomeric Kv7.2 R144W/Q/G channels was left-shifted, suggesting gain-of-function effects. Amitriptyline blocked channels containing Kv7.2 and Kv7.2 R144Q subunits. Interpretation Patients carrying KCNQ2 R144 gain-of-function variants have developmental delay with prominent language impairment, autistic features, often accompanied by infantile- to childhood-onset epilepsy and EEG sleep-activated epileptiform activity. The absence of neonatal seizures is a robust and important clinical differentiator between KCNQ2 gain-of-function and loss-of-function variants. The Kv7.2/7.3 channel blocker amitriptyline might represent a targeted treatment. Funding Supported by FWO, GSKE, KCNQ2-Cure, Jack Pribaz Foundation, European Joint Programme on Rare Disease 2020, the Italian Ministry for University and Research, the Italian Ministry of Health, the European Commission, the University of Antwerp, NINDS, and Chalk Family Foundation.
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Singh SP, William M, Malavia M, Chu XP. Behavior of KCNQ Channels in Neural Plasticity and Motor Disorders. MEMBRANES 2022; 12:membranes12050499. [PMID: 35629827 PMCID: PMC9143857 DOI: 10.3390/membranes12050499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/26/2022] [Accepted: 05/03/2022] [Indexed: 02/01/2023]
Abstract
The broad distribution of voltage-gated potassium channels (VGKCs) in the human body makes them a critical component for the study of physiological and pathological function. Within the KCNQ family of VGKCs, these aqueous conduits serve an array of critical roles in homeostasis, especially in neural tissue. Moreover, the greater emphasis on genomic identification in the past century has led to a growth in literature on the role of the ion channels in pathological disease as well. Despite this, there is a need to consolidate the updated findings regarding both the pharmacotherapeutic and pathological roles of KCNQ channels, especially regarding neural plasticity and motor disorders which have the largest body of literature on this channel. Specifically, KCNQ channels serve a remarkable role in modulating the synaptic efficiency required to create appropriate plasticity in the brain. This role can serve as a foundation for clinical approaches to chronic pain. Additionally, KCNQ channels in motor disorders have been utilized as a direction for contemporary pharmacotherapeutic developments due to the muscarinic properties of this channel. The aim of this study is to provide a contemporary review of the behavior of these channels in neural plasticity and motor disorders. Upon review, the behavior of these channels is largely dependent on the physiological role that KCNQ modulatory factors (i.e., pharmacotherapeutic options) serve in pathological diseases.
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Xiong J, Chen S, Chen B, Zhang W, Chen C, Deng X, He F, Zhang C, Yang L, Wang Y, Peng J, Yin F. A novel KCNQ2 missense variant in non-syndromic intellectual disability causes mild gain-of-function of Kv7.2 channel. Clin Chim Acta 2022; 530:74-80. [PMID: 35247435 DOI: 10.1016/j.cca.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/01/2022] [Indexed: 11/26/2022]
Abstract
BACKGROUND Heterozygous variants of KCNQ2 can cause KCNQ2 associated neurodevelopmental disorder, mainly are benign (familial) neonatal or infantile epilepsy (B(F)NE or B(F)IE) and early-onset epileptic encephalopathy (EOEE). Moreover, some intermediate phenotypes, including intellectual disability (ID), and myokymia are related to the gene. METHODS We collected a non-syndromic ID male patient with a novel KCNQ2 missense variant. Whole cell electrophysiology, western blotting, and immunofluorescence were adopted to analyze the variant's functional alterations. RESULTS The patient presented with global developmental delay since his infancy. He still had profound ID but did not have epilepsy at the adolescence. The de novo KCNQ2 variant p.R75C (NM_172107) in the NH2 domain identified here showed a slightly hyperpolarized shift of activation curves and larger current density in homomeric configurations, which could be abolished in co-expression with Kv7.2 or Kv7.3 wild-type. Western blotting and immunocytochemistry supported that the expression of variant p.R75C is lower than the Kv7.2 wild-type. The findings indicated variant p.R75C cause mild gain-of-function (GOF) of Kv7.2 channel. CONCLUSIONS We report a non-syndromic ID patient with a KCNQ2 mild GOF variant, adding evidence for this rare clinical phenotype in the disorder. We propose that individuals with KCNQ2 GOF variants are prone to have cognitive impairments.
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Affiliation(s)
- Juan Xiong
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Shimeng Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Baiyu Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Wen Zhang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Chen Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Xiaolu Deng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Ciliu Zhang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Lifen Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Ying Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China.
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8
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Panagiotakos G, Pasca SP. A matter of space and time: Emerging roles of disease-associated proteins in neural development. Neuron 2022; 110:195-208. [PMID: 34847355 PMCID: PMC8776599 DOI: 10.1016/j.neuron.2021.10.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/11/2021] [Accepted: 10/25/2021] [Indexed: 01/21/2023]
Abstract
Recent genetic studies of neurodevelopmental disorders point to synaptic proteins and ion channels as key contributors to disease pathogenesis. Although many of these proteins, such as the L-type calcium channel Cav1.2 or the postsynaptic scaffolding protein SHANK3, have well-studied functions in mature neurons, new evidence indicates that they may subserve novel, distinct roles in immature cells as the nervous system is assembled in prenatal development. Emerging tools and technologies, including single-cell sequencing and human cellular models of disease, are illuminating differential isoform utilization, spatiotemporal expression, and subcellular localization of ion channels and synaptic proteins in the developing brain compared with the adult, providing new insights into the regulation of developmental processes. We propose that it is essential to consider the temporally distinct and cell-specific roles of these proteins during development and maturity in our framework for understanding neuropsychiatric disorders.
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Affiliation(s)
- Georgia Panagiotakos
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA.
| | - Sergiu P Pasca
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA; Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA.
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9
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Posttranscriptional modulation of KCNQ2 gene expression by the miR-106b microRNA family. Proc Natl Acad Sci U S A 2021; 118:2110200118. [PMID: 34785595 DOI: 10.1073/pnas.2110200118] [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] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
MicroRNAs (miRNAs) have recently emerged as important regulators of ion channel expression. We show here that select miR-106b family members repress the expression of the KCNQ2 K+ channel protein by binding to the 3'-untranslated region of KCNQ2 messenger RNA. During the first few weeks after birth, the expression of miR-106b family members rapidly decreases, whereas KCNQ2 protein level inversely increases. Overexpression of miR-106b mimics resulted in a reduction in KCNQ2 protein levels. Conversely, KCNQ2 levels were up-regulated in neurons transfected with antisense miRNA inhibitors. By constructing more specific and stable forms of miR-106b controlling systems, we further confirmed that overexpression of precursor-miR-106b-5p led to a decrease in KCNQ current density and an increase in firing frequency of hippocampal neurons, while tough decoy miR-106b-5p dramatically increased current density and decreased neuronal excitability. These results unmask a regulatory mechanism of KCNQ2 channel expression in early postnatal development and hint at a role for miR-106b up-regulation in the pathophysiology of epilepsy.
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10
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Kwon CM, Lee KH. KCNQ2-Related Benign Infantile Epilepsy in Preterm Dizygotic Twins. ANNALS OF CHILD NEUROLOGY 2021. [DOI: 10.26815/acn.2021.00493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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11
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Loss of KCNQ2 or KCNQ3 Leads to Multifocal Time-Varying Activity in the Neonatal Forebrain Ex Vivo. eNeuro 2021; 8:ENEURO.0024-21.2021. [PMID: 33863780 PMCID: PMC8143017 DOI: 10.1523/eneuro.0024-21.2021] [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: 01/19/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 12/29/2022] Open
Abstract
Epileptic encephalopathies represent a group of disorders often characterized by refractory seizures, regression in cognitive development, and typically poor prognosis. Dysfunction of KCNQ2 and KCNQ3 channels has emerged as a major cause of neonatal epilepsy. However, our understanding of the cellular mechanisms that may both explain the origins of epilepsy and inform treatment strategies for KCNQ2 and KCNQ3 dysfunction is still lacking. Here, using mesoscale calcium imaging and pharmacology, we demonstrate that in mouse neonatal brain slices, conditional loss of Kcnq2 from forebrain excitatory neurons (Pyr:Kcnq2 mice) or constitutive deletion of Kcnq3 leads to sprawling hyperactivity across the neocortex. Surprisingly, the generation of time-varying hypersynchrony in slices from Pyr:Kcnq2 mice does not require fast synaptic transmission. This is in contrast to control littermates and constitutive Kcnq3 knock-out mice where activity is primarily driven by fast synaptic transmission in the neocortex. Unlike in the neocortex, hypersynchronous activity in the hippocampal formation from Kcnq2 conditional and Kcnq3 constitutive knock-out mice persists in the presence of synaptic transmission blockers. Thus, we propose that loss of KCNQ2 or KCNQ3 function differentially leads to network hyperactivity across the forebrain in a region-specific and macro-circuit-specific manner.
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12
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Springer K, Varghese N, Tzingounis AV. Flexible Stoichiometry: Implications for KCNQ2- and KCNQ3-Associated Neurodevelopmental Disorders. Dev Neurosci 2021; 43:191-200. [PMID: 33794528 PMCID: PMC8440324 DOI: 10.1159/000515495] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/25/2021] [Indexed: 11/19/2022] Open
Abstract
KCNQ2 and KCNQ3 pathogenic channel variants have been associated with a spectrum of developmentally regulated diseases that vary in age of onset, severity, and whether it is transient (i.e., benign familial neonatal seizures) or long-lasting (i.e., developmental and epileptic encephalopathy). KCNQ2 and KCNQ3 channels have also emerged as a target for novel antiepileptic drugs as their activation could reduce epileptic activity. Consequently, a great effort has taken place over the last 2 decades to understand the mechanisms that control the assembly, gating, and modulation of KCNQ2 and KCNQ3 channels. The current view that KCNQ2 and KCNQ3 channels assemble as heteromeric channels (KCNQ2/3) forms the basis of our understanding of KCNQ2 and KCNQ3 channelopathies and drug design. Here, we review the evidence that supports the formation of KCNQ2/3 heteromers in neurons. We also highlight functional and transcriptomic studies that suggest channel composition might not be necessarily fixed in the nervous system, but rather is dynamic and flexible, allowing some neurons to express KCNQ2 and KCNQ3 homomers. We propose that to fully understand KCNQ2 and KCNQ3 channelopathies, we need to adopt a more flexible view of KCNQ2 and KCNQ3 channel stoichiometry, which might differ across development, brain regions, cell types, and disease states.
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Affiliation(s)
- Kristen Springer
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Nissi Varghese
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
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13
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Berg AT, Mahida S, Poduri A. KCNQ2-DEE: developmental or epileptic encephalopathy? Ann Clin Transl Neurol 2021; 8:666-676. [PMID: 33616268 PMCID: PMC7951099 DOI: 10.1002/acn3.51316] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 12/12/2022] Open
Abstract
Objective KCNQ2‐associated developmental and epileptic encephalopathies (DEE) present with seizures and developmental impairments. The relation between seizures and functional impairments in affected children and the relation of a specific genetic variant to seizure control remains unknown. Methods Parents of children with documented KCNQ2 variants who participated in a structured, online natural history survey provided information about seizure history, functional mobility, hand use, communication function, and feeding independence. Bivariate analyses were performed with nonparametric methods and logistic regression was used for multivariable analyses. Results Thirty‐nine children (20, 51% girls, median age 4.5 years, interquartile range (IQR) 1.9—19.3) had a median age of seizure onset of 1 day (IQR 1—3 days). The most common seizure types were bilateral tonic‐clonic (N = 72, 28%) and bilateral tonic (N = 13, 33%). Time since last seizure was <6 months (N = 18, 46%), 6–23 months (N = 11, 28%), and ≥24 months (N = 10 26%). Severe functional impairment was reported for mobility (62%), hand grasp (31%), feeding (59%), and communication (77%). Twenty‐eight (72%) were impaired in ≥2 domains. There were only weak and inconsistent associations between seizure recency and individual impairments or number of impairments after adjustment for other factors. The functional location of the variants within the Kv7.2 protein was not associated with seizure control. Interpretation Seizures in KCNQ2‐DEE are often well‐controlled, but children have severe impairments regardless. With the increased potential for precision therapies targeting the Kv7.2 channel or the KCNQ2 gene itself, identifying the most relevant and sensitive clinical endpoints will be critical to ensure successful trials of new therapies.
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Affiliation(s)
- Anne T Berg
- Division of Neurology, Epilepsy Center, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.,Department of Pediatrics, Northwestern Feinberg School of Medicine, Chicago, Illinois, USA
| | - Sonal Mahida
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Neurology, Harvard Medical School, Boston, Massachusetts, USA.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
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14
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Abstract
Kv7.1-Kv7.5 (KCNQ1-5) K+ channels are voltage-gated K+ channels with major roles in neurons, muscle cells and epithelia where they underlie physiologically important K+ currents, such as neuronal M current and cardiac IKs. Specific biophysical properties of Kv7 channels make them particularly well placed to control the activity of excitable cells. Indeed, these channels often work as 'excitability breaks' and are targeted by various hormones and modulators to regulate cellular activity outputs. Genetic deficiencies in all five KCNQ genes result in human excitability disorders, including epilepsy, arrhythmias, deafness and some others. Not surprisingly, this channel family attracts considerable attention as potential drug targets. Here we will review biophysical properties and tissue expression profile of Kv7 channels, discuss recent advances in the understanding of their structure as well as their role in various neurological, cardiovascular and other diseases and pathologies. We will also consider a scope for therapeutic targeting of Kv7 channels for treatment of the above health conditions.
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15
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Maghera J, Li J, Lamothe SM, Braun M, Appendino JP, Au PYB, Kurata HT. Familial neonatal seizures caused by the Kv7.3 selectivity filter mutation T313I. Epilepsia Open 2020; 5:562-573. [PMID: 33336127 PMCID: PMC7733659 DOI: 10.1002/epi4.12438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 08/14/2020] [Accepted: 09/09/2020] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE A spectrum of seizure disorders is linked to mutations in Kv7.2 and Kv7.3 channels. Linking functional effects of identified mutations to their clinical presentation requires ongoing characterization of newly identified variants. In this study, we identified and functionally characterized a previously unreported mutation in the selectivity filter of Kv7.3. METHODS Next-generation sequencing was used to identify the Kv7.3[T313I] mutation in a family affected by neonatal seizures. Electrophysiological approaches were used to characterize the functional effects of this mutation on ion channels expressed in Xenopus laevis oocytes. RESULTS Substitution of residue 313 from threonine to isoleucine (Kv7.3[T313I]) likely disrupts a critical intersubunit hydrogen bond. Characterization of the mutation in homomeric Kv7.3 channels demonstrated a total loss of channel function. Assembly in heteromeric channels (with Kv7.2) leads to modest suppression of total current when expressed in Xenopus laevis oocytes. Using a Kv7 activator with distinct effects on homomeric Kv7.2 vs heteromeric Kv7.2/Kv7.3 channels, we demonstrated that assembly of Kv7.2 and Kv7.3[T313I] generates functional channels. SIGNIFICANCE Biophysical and clinical effects of the T313I mutation are consistent with Kv7.3 mutations previously identified in cases of pharmacoresponsive self-limiting neonatal epilepsy. These findings expand our description of functionally characterized Kv7 channel variants and report new methods to distinguish molecular mechanisms of channel mutations.
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Affiliation(s)
- Jasmine Maghera
- Department of PharmacologyAlberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Jingru Li
- Department of PharmacologyAlberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Shawn M. Lamothe
- Department of PharmacologyAlberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Marvin Braun
- Division of Child NeurologyDepartment of PediatricsWeill Cornell MedicineNew YorkNYUSA
| | - Juan P. Appendino
- Section of NeurologyDepartment of PediatricsCumming School of MedicineUniversity of Calgary, and Alberta Children’s HospitalCalgaryABCanada
| | - P. Y. Billie Au
- Department of Medical GeneticsCumming School of MedicineAlberta Children’s Hospital Research InstituteUniversity of CalgaryCalgaryABCanada
| | - Harley T. Kurata
- Department of PharmacologyAlberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
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16
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Dirkx N, Miceli F, Taglialatela M, Weckhuysen S. The Role of Kv7.2 in Neurodevelopment: Insights and Gaps in Our Understanding. Front Physiol 2020; 11:570588. [PMID: 33192566 PMCID: PMC7657400 DOI: 10.3389/fphys.2020.570588] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/07/2020] [Indexed: 11/13/2022] Open
Abstract
Kv7.2 subunits encoded by the KCNQ2 gene constitute a critical molecular component of the M-current, a subthreshold voltage-gated potassium current controlling neuronal excitability by dampening repetitive action potential firing. Pathogenic loss-of-function variants in KCNQ2 have been linked to epilepsy since 1998, and there is ample functional evidence showing that dysfunction of the channel indeed results in neuronal hyperexcitability. The recent description of individuals with severe developmental delay with or without seizures due to pathogenic variants in KCNQ2 (KCNQ2-encephalopathy) reveals that Kv7.2 channels also have an important role in neurodevelopment. Kv7.2 channels are expressed already very early in the developing brain when key developmental processes such as proliferation, differentiation, and synaptogenesis play a crucial role in brain morphogenesis and maturation. In this review, we will discuss the available evidence for a role of Kv7.2 channels in these neurodevelopmental processes, focusing in particular on insights derived from KCNQ2-related human phenotypes, from the spatio-temporal expression of Kv7.2 and other Kv7 family member, and from cellular and rodent models, highlighting critical gaps and research strategies to be implemented in the future. Lastly, we propose a model which divides the M-current activity in three different developmental stages, correlating with the cell characteristics during these particular periods in neuronal development, and how this can be linked with KCNQ2-related disorders. Understanding these mechanisms can create opportunities for new targeted therapies for KCNQ2-encephalopathy.
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Affiliation(s)
- Nina Dirkx
- Applied and Translational Neurogenomics Group, VIB Center for Molecular Neurology, Vlaams Instituut voor Biotechnologie, Antwerp, Belgium
| | - Francesco Miceli
- Section of Pharmacology, Department of Neuroscience, University of Naples Federico II, Naples, Italy
| | - Maurizio Taglialatela
- Section of Pharmacology, Department of Neuroscience, University of Naples Federico II, Naples, Italy
| | - Sarah Weckhuysen
- Applied and Translational Neurogenomics Group, VIB Center for Molecular Neurology, Vlaams Instituut voor Biotechnologie, Antwerp, Belgium.,Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
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17
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Miceli F, Carotenuto L, Barrese V, Soldovieri MV, Heinzen EL, Mandel AM, Lippa N, Bier L, Goldstein DB, Cooper EC, Cilio MR, Taglialatela M, Sands TT. A Novel Kv7.3 Variant in the Voltage-Sensing S 4 Segment in a Family With Benign Neonatal Epilepsy: Functional Characterization and in vitro Rescue by β-Hydroxybutyrate. Front Physiol 2020; 11:1040. [PMID: 33013448 PMCID: PMC7498716 DOI: 10.3389/fphys.2020.01040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 07/29/2020] [Indexed: 01/09/2023] Open
Abstract
Pathogenic variants in KCNQ2 and KCNQ3, paralogous genes encoding Kv7.2 and Kv7.3 voltage-gated K+ channel subunits, are responsible for early-onset developmental/epileptic disorders characterized by heterogeneous clinical phenotypes ranging from benign familial neonatal epilepsy (BFNE) to early-onset developmental and epileptic encephalopathy (DEE). KCNQ2 variants account for the majority of pedigrees with BFNE and KCNQ3 variants are responsible for a much smaller subgroup, but the reasons for this imbalance remain unclear. Analysis of additional pedigrees is needed to further clarify the nature of this genetic heterogeneity and to improve prediction of pathogenicity for novel variants. We identified a BFNE family with two siblings and a parent affected. Exome sequencing on samples from both parents and siblings revealed a novel KCNQ3 variant (c.719T>G; p.M240R), segregating in the three affected individuals. The M240 residue is conserved among human Kv7.2-5 and lies between the two arginines (R5 and R6) closest to the intracellular side of the voltage-sensing S4 transmembrane segment. Whole cell patch-clamp recordings in Chinese hamster ovary (CHO) cells revealed that homomeric Kv7.3 M240R channels were not functional, whereas heteromeric channels incorporating Kv7.3 M240R mutant subunits with Kv7.2 and Kv7.3 displayed a depolarizing shift of about 10 mV in activation gating. Molecular modeling results suggested that the M240R substitution preferentially stabilized the resting state and possibly destabilized the activated state of the Kv7.3 subunits, a result consistent with functional data. Exposure to β-hydroxybutyrate (BHB), a ketone body generated during the ketogenic diet (KD), reversed channel dysfunction induced by the M240R variant. In conclusion, we describe the first missense loss-of-function (LoF) pathogenic variant within the S4 segment of Kv7.3 identified in patients with BFNE. Studied under conditions mimicking heterozygosity, the M240R variant mainly affects the voltage sensitivity, in contrast to previously analyzed BFNE Kv7.3 variants that reduce current density. Our pharmacological results provide a rationale for the use of KD in patients carrying LoF variants in Kv7.2 or Kv7.3 subunits.
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Affiliation(s)
- Francesco Miceli
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Lidia Carotenuto
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Vincenzo Barrese
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | | | - Erin L Heinzen
- Eshelman School of Pharmacy, Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.,Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Arthur M Mandel
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | - Natalie Lippa
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Louise Bier
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - David B Goldstein
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Edward C Cooper
- Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Maria Roberta Cilio
- Department of Pediatrics and Institute of Experimental and Clinical Research, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | | | - Tristan T Sands
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States.,Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
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18
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Yamamoto A, Saito Y, Oyama Y, Watanabe Y, Ikeda A, Takayama R, Ikeda H, Takeshita S, Takumi I, Itai T, Miyatake S, Matsumoto N. Effect of total callosotomy on KCNQ2-related intractable epilepsy. Brain Dev 2020; 42:612-616. [PMID: 32532640 DOI: 10.1016/j.braindev.2020.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/18/2020] [Accepted: 05/18/2020] [Indexed: 11/25/2022]
Abstract
AIM To describe beneficial effects of callosotomy on KCNQ2-related intractable epilepsy. CASE REPORT Our patient was a 10-year-old girl who had developed epilepsy during the neonatal period, accompanied by a suppression-burst pattern on the electroencephalography (EEG). The patient showed profound psychomotor developmental delay since early infancy. Daily seizures of versive posturing and ocular deviation were transiently controlled by carbamazepine and valproate at the age of 1 year; however, the seizures gradually increased to up to 50 times per day. Ictal EEG and positron emission tomography revealed an epileptic focus in the left frontal lobe at age 5 years. Total callosotomy resulted in marked reduction of epileptic seizures thereafter, as well as improved responses to external auditory and visual stimuli. Whole exome sequencing at age 9 identified a de novo missense variant in KCNQ2 (NM_172107.3:c.563A > C:p.(Gln188Pro)). CONCLUSION This case supports that epilepsy surgery could benefit children with epileptic encephalopathy, even with the etiology of channelopathy.
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Affiliation(s)
- Ayako Yamamoto
- Department of Pediatrics, Yokohama City University Medical Center, 4-57 Urafune, Minami-ku, Yokohama 232-0024, Japan.
| | - Yoshiaki Saito
- Department of Pediatrics, Yokohama City University Medical Center, 4-57 Urafune, Minami-ku, Yokohama 232-0024, Japan; Division of Child Neurology, Yokohama Medical and Welfare Center, Konan, 4-6-20 Konan-ku, Yokohama 234-0054, Japan
| | - Yoshitaka Oyama
- Department of Pediatrics, Yokohama City University Medical Center, 4-57 Urafune, Minami-ku, Yokohama 232-0024, Japan
| | - Yoshihiro Watanabe
- Department of Pediatrics, Yokohama City University Medical Center, 4-57 Urafune, Minami-ku, Yokohama 232-0024, Japan
| | - Azusa Ikeda
- Department of Pediatrics, Yokohama City University Medical Center, 4-57 Urafune, Minami-ku, Yokohama 232-0024, Japan
| | - Rumiko Takayama
- Department of Pediatrics, National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka 420-8688, Japan
| | - Hiroko Ikeda
- Department of Pediatrics, National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka 420-8688, Japan
| | - Saoko Takeshita
- Department of Pediatrics, Yokohama City University Medical Center, 4-57 Urafune, Minami-ku, Yokohama 232-0024, Japan
| | - Ichiro Takumi
- Department of Neurological Surgery, Nippon Medical School Musashi Kosugi Hospital, 1-396 Kosugi-cho, Nakahara-ku, Kawasaki 211-8553, Japan; Department of Neurosurgery, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki 216-8511, Japan
| | - Toshiyuki Itai
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-2606, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-2606, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-2606, Japan
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19
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Heteromeric Kv7.2 current changes caused by loss-of-function of KCNQ2 mutations are correlated with long-term neurodevelopmental outcomes. Sci Rep 2020; 10:13375. [PMID: 32770121 PMCID: PMC7415140 DOI: 10.1038/s41598-020-70212-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 07/22/2020] [Indexed: 12/19/2022] Open
Abstract
Pediatric epilepsy caused by KCNQ2 mutations can manifest benign familial neonatal convulsions (BFNC) to neonatal-onset epileptic encephalopathy (EE). Patients might manifest mild to profound neurodevelopmental disabilities. We analysed c.853C > A (P285T) and three mutations that cause KCNQ2 protein changes in the 247 position: c.740C > T (S247L), c.740C > A (S247X), and c.740C > G (S247W). S247L, S247W, and P285T cause neonatal-onset EE and poor neurodevelopmental outcomes; S247X cause BFNC and normal outcome. We investigated the phenotypes correlated with human embryonic kidney 293 (HEK293) cell functional current changes. More cell-current changes and a worse conductance curve were present in the homomeric transfected S247X than in S247L, S247W, and P285T. But in the heteromeric channel, S247L, S247W and P285T had more current impairments than did S247X. The protein expressions of S247X were nonfunctional. The outcomes were most severe in S247L and S247W, and severity was correlated with heteromeric current. Current changes were more significant in cells with homomeric S247X, but currents were “rescued” after heteromeric transfection of KCNQ2 and KCNQ3. This was not the case in cells with S247L, S247W. Our findings support that homomeric current changes are common in KCNQ2 neonatal-onset EE and KCNQ2 BFNC; however, heteromeric functional current changes are correlated with long-term neurodevelopmental outcomes.
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20
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Wilenkin B, Burris KD, Eastwood BJ, Sher E, Williams AC, Priest BT. Development of an Electrophysiological Assay for Kv7 Modulators on IonWorks Barracuda. Assay Drug Dev Technol 2020; 17:310-321. [PMID: 31634018 DOI: 10.1089/adt.2019.942] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Relief from chronic pain continues to represent a large unmet need. The voltage-gated potassium channel Kv7.2/7.3, also known as KCNQ2/3, is a key contributor to the control of resting membrane potential and excitability in nociceptive neurons and represents a promising target for potential therapeutics. In this study, we present a medium throughput electrophysiological assay for the identification and characterization of modulators of Kv7.2/7.3 channels, using the IonWorks Barracuda™ automated voltage clamp platform. The assay combines a family of voltage steps used to construct conductance curves with a unique analysis method. Kv7.2/7.3 modulators shift the activation voltage and/or change the maximal conductance of the current, and both parameters have been used to quantify compound mediated effects. Both effects are expected to modulate neuronal excitability in vivo. The analysis method described assigns a single potency value that combines changes in activation voltage and maximal conductance and is expected to predict compound mediated changes in excitability.
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Affiliation(s)
- Benjamin Wilenkin
- Department of Quantitative Biology, Eli Lilly and Company, Indianapolis, Indiana
| | - Kevin D Burris
- Department of Quantitative Biology, Eli Lilly and Company, Indianapolis, Indiana
| | - Brian J Eastwood
- Department of Statistics, Eli Lilly and Company, Indianapolis, Indiana
| | - Emanuele Sher
- Department of Discovery Pain Group, Eli Lilly and Company, Indianapolis, Indiana
| | - Andrew C Williams
- Department of Medicinal Chemistry, Eli Lilly and Company, Indianapolis, Indiana
| | - Birgit T Priest
- Department of Quantitative Biology, Eli Lilly and Company, Indianapolis, Indiana
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21
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Nappi P, Miceli F, Soldovieri MV, Ambrosino P, Barrese V, Taglialatela M. Epileptic channelopathies caused by neuronal Kv7 (KCNQ) channel dysfunction. Pflugers Arch 2020; 472:881-898. [PMID: 32506321 DOI: 10.1007/s00424-020-02404-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 05/12/2020] [Accepted: 05/18/2020] [Indexed: 11/28/2022]
Abstract
Seizures are the most common neurological manifestation in the newborn period, with an estimated incidence of 1.8-3.5 per 1000 live births. Prolonged or intractable seizures have a detrimental effect on cognition and brain function in experimental animals and are associated with adverse long-term neurodevelopmental sequelae and an increased risk of post-neonatal epilepsy in humans. The developing brain is particularly susceptible to the potentially severe effects of epilepsy, and epilepsy, especially when refractory to medications, often results in a developmental and epileptic encephalopathy (DEE) with developmental arrest or regression. DEEs can be primarily attributed to genetic causes. Given the critical role of potassium (K+) currents with distinct subcellular localization, biophysical properties, modulation, and pharmacological profile in regulating intrinsic electrical properties of neurons and their responsiveness to synaptic inputs, it is not too surprising that genetic research in the past two decades has identified several K+ channel genes as responsible for a large fraction of DEE. In the present article, we review the genetically determined epileptic channelopathies affecting three members of the Kv7 family, namely Kv7.2 (KCNQ2), Kv7.3 (KCNQ3), and Kv7.5 (KCNQ5); we review the phenotypic spectrum of Kv7-related epileptic channelopathies, the different genetic and pathogenetic mechanisms, and the emerging genotype-phenotype correlations which may prove crucial for prognostic predictions, disease management, parental counseling, and individually tailored therapeutic attempts.
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Affiliation(s)
- Piera Nappi
- Section of Pharmacology, Department of Neuroscience, University of Naples, "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Francesco Miceli
- Section of Pharmacology, Department of Neuroscience, University of Naples, "Federico II", Via Pansini 5, 80131, Naples, Italy
| | | | - Paolo Ambrosino
- Department of Science and Technology (DST), University of Sannio, Benevento, Italy
| | - Vincenzo Barrese
- Section of Pharmacology, Department of Neuroscience, University of Naples, "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Maurizio Taglialatela
- Section of Pharmacology, Department of Neuroscience, University of Naples, "Federico II", Via Pansini 5, 80131, Naples, Italy.
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22
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Ambrosino P, Soldovieri MV, Di Zazzo E, Paventi G, Iannotti FA, Mosca I, Miceli F, Franco C, Canzoniero LMT, Taglialatela M. Activation of Kv7 Potassium Channels Inhibits Intracellular Ca 2+ Increases Triggered By TRPV1-Mediated Pain-Inducing Stimuli in F11 Immortalized Sensory Neurons. Int J Mol Sci 2019; 20:ijms20184322. [PMID: 31487785 PMCID: PMC6769798 DOI: 10.3390/ijms20184322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/01/2019] [Accepted: 09/02/2019] [Indexed: 12/11/2022] Open
Abstract
Kv7.2-Kv7.5 channels mediate the M-current (IKM), a K+-selective current regulating neuronal excitability and representing an attractive target for pharmacological therapy against hyperexcitability diseases such as pain. Kv7 channels interact functionally with transient receptor potential vanilloid 1 (TRPV1) channels activated by endogenous and/or exogenous pain-inducing substances, such as bradykinin (BK) or capsaicin (CAP), respectively; however, whether Kv7 channels of specific molecular composition provide a dominant contribution in BK- or CAP-evoked responses is yet unknown. To this aim, Kv7 transcripts expression and function were assessed in F11 immortalized sensorial neurons, a cellular model widely used to assess nociceptive molecular mechanisms. In these cells, the effects of the pan-Kv7 activator retigabine were investigated, as well as the effects of ICA-27243 and (S)-1, two Kv7 activators acting preferentially on Kv7.2/Kv7.3 and Kv7.4/Kv7.5 channels, respectively, on BK- and CAP-induced changes in intracellular Ca2+ concentrations ([Ca2+]i). The results obtained revealed the expression of transcripts of all Kv7 genes, leading to an IKM-like current. Moreover, all tested Kv7 openers inhibited BK- and CAP-induced responses by a similar extent (~60%); at least for BK-induced Ca2+ responses, the potency of retigabine (IC50~1 µM) was higher than that of ICA-27243 (IC50~5 µM) and (S)-1 (IC50~7 µM). Altogether, these results suggest that IKM activation effectively counteracts the cellular processes triggered by TRPV1-mediated pain-inducing stimuli, and highlight a possible critical contribution of Kv7.4 subunits.
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Affiliation(s)
- Paolo Ambrosino
- Department of Science and Technology, University of Sannio, 82100 Benevento, Italy
| | - Maria Virginia Soldovieri
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, 86100 Campobasso, Italy
| | - Erika Di Zazzo
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, 86100 Campobasso, Italy
| | - Gianluca Paventi
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, 86100 Campobasso, Italy
| | - Fabio Arturo Iannotti
- Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, 80121 Naples, Italy
| | - Ilaria Mosca
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, 86100 Campobasso, Italy
| | - Francesco Miceli
- Division of Pharmacology, Department of Neuroscience, University of Naples "Federico II", 80131 Naples, Italy
| | - Cristina Franco
- Department of Science and Technology, University of Sannio, 82100 Benevento, Italy
| | | | - Maurizio Taglialatela
- Division of Pharmacology, Department of Neuroscience, University of Naples "Federico II", 80131 Naples, Italy.
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23
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Lauritano A, Moutton S, Longobardi E, Tran Mau‐Them F, Laudati G, Nappi P, Soldovieri MV, Ambrosino P, Cataldi M, Jouan T, Lehalle D, Maurey H, Philippe C, Miceli F, Vitobello A, Taglialatela M. A novel homozygous KCNQ3 loss-of-function variant causes non-syndromic intellectual disability and neonatal-onset pharmacodependent epilepsy. Epilepsia Open 2019; 4:464-475. [PMID: 31440727 PMCID: PMC6698674 DOI: 10.1002/epi4.12353] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/04/2019] [Accepted: 07/28/2019] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Heterozygous variants in KCNQ2 or, more rarely, KCNQ3 genes are responsible for early-onset developmental/epileptic disorders characterized by heterogeneous clinical presentation and course, genetic transmission, and prognosis. While familial forms mostly include benign epilepsies with seizures starting in the neonatal or early-infantile period, de novo variants in KCNQ2 or KCNQ3 have been described in sporadic cases of early-onset encephalopathy (EOEE) with pharmacoresistant seizures, various age-related pathological EEG patterns, and moderate/severe developmental impairment. All pathogenic variants in KCNQ2 or KCNQ3 occur in heterozygosity. The aim of this work was to report the clinical, molecular, and functional properties of a new KCNQ3 variant found in homozygous configuration in a 9-year-old girl with pharmacodependent neonatal-onset epilepsy and non-syndromic intellectual disability. METHODS Exome sequencing was used for genetic investigation. KCNQ3 transcript and subunit expression in fibroblasts was analyzed with quantitative real-time PCR and Western blotting or immunofluorescence, respectively. Whole-cell patch-clamp electrophysiology was used for functional characterization of mutant subunits. RESULTS A novel single-base duplication in exon 12 of KCNQ3 (NM_004519.3:c.1599dup) was found in homozygous configuration in the proband born to consanguineous healthy parents; this frameshift variant introduced a premature termination codon (PTC), thus deleting a large part of the C-terminal region. Mutant KCNQ3 transcript and protein abundance was markedly reduced in primary fibroblasts from the proband, consistent with nonsense-mediated mRNA decay. The variant fully abolished the ability of KCNQ3 subunits to assemble into functional homomeric or heteromeric channels with KCNQ2 subunits. SIGNIFICANCE The present results indicate that a homozygous KCNQ3 loss-of-function variant is responsible for a severe phenotype characterized by neonatal-onset pharmacodependent seizures, with developmental delay and intellectual disability. They also reveal difference in genetic and pathogenetic mechanisms between KCNQ2- and KCNQ3-related epilepsies, a crucial observation for patients affected with EOEE and/or developmental disabilities.
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Affiliation(s)
- Anna Lauritano
- Division of Pharmacology, Department of NeuroscienceUniversity of Naples “Federico II”NaplesItaly
| | - Sebastien Moutton
- Reference Center for Developmental Anomalies, Department of Medical GeneticsDijon University HospitalDijonFrance
- INSERM U1231, LNC UMR1231 GADBurgundy UniversityDijonFrance
| | - Elena Longobardi
- Division of Pharmacology, Department of NeuroscienceUniversity of Naples “Federico II”NaplesItaly
| | - Frédéric Tran Mau‐Them
- INSERM U1231, LNC UMR1231 GADBurgundy UniversityDijonFrance
- Laboratoire de Génétique, Innovation en Diagnostic Génomique des Maladies Rares UF6254, Plateau Technique de BiologieCHU DijonDijonFrance
| | - Giusy Laudati
- Division of Pharmacology, Department of NeuroscienceUniversity of Naples “Federico II”NaplesItaly
| | - Piera Nappi
- Division of Pharmacology, Department of NeuroscienceUniversity of Naples “Federico II”NaplesItaly
| | | | - Paolo Ambrosino
- Division of Pharmacology, Department of Science and TechnologyUniversity of SannioBeneventoItaly
| | - Mauro Cataldi
- Division of Pharmacology, Department of NeuroscienceUniversity of Naples “Federico II”NaplesItaly
| | - Thibaud Jouan
- INSERM U1231, LNC UMR1231 GADBurgundy UniversityDijonFrance
- Laboratoire de Génétique, Innovation en Diagnostic Génomique des Maladies Rares UF6254, Plateau Technique de BiologieCHU DijonDijonFrance
| | - Daphné Lehalle
- Reference Center for Developmental Anomalies, Department of Medical GeneticsDijon University HospitalDijonFrance
- INSERM U1231, LNC UMR1231 GADBurgundy UniversityDijonFrance
| | - Hélène Maurey
- Service de Neurologie PédiatriqueAPHP, Hôpital Universitaire BicêtreLe Kremlin‐BicêtreFrance
| | - Christophe Philippe
- INSERM U1231, LNC UMR1231 GADBurgundy UniversityDijonFrance
- Laboratoire de Génétique, Innovation en Diagnostic Génomique des Maladies Rares UF6254, Plateau Technique de BiologieCHU DijonDijonFrance
| | - Francesco Miceli
- Division of Pharmacology, Department of NeuroscienceUniversity of Naples “Federico II”NaplesItaly
| | - Antonio Vitobello
- INSERM U1231, LNC UMR1231 GADBurgundy UniversityDijonFrance
- Laboratoire de Génétique, Innovation en Diagnostic Génomique des Maladies Rares UF6254, Plateau Technique de BiologieCHU DijonDijonFrance
| | - Maurizio Taglialatela
- Division of Pharmacology, Department of NeuroscienceUniversity of Naples “Federico II”NaplesItaly
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24
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Epileptic Encephalopathy In A Patient With A Novel Variant In The Kv7.2 S2 Transmembrane Segment: Clinical, Genetic, and Functional Features. Int J Mol Sci 2019; 20:ijms20143382. [PMID: 31295832 PMCID: PMC6678645 DOI: 10.3390/ijms20143382] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/04/2019] [Accepted: 07/05/2019] [Indexed: 11/18/2022] Open
Abstract
Kv7.2 subunits encoded by the KCNQ2 gene provide a major contribution to the M-current (IKM), a voltage-gated K+ current crucially involved in the regulation of neuronal excitability. Heterozygous missense variants in Kv7.2 are responsible for epileptic diseases characterized by highly heterogeneous genetic transmission and clinical severity, ranging from autosomal-dominant Benign Familial Neonatal Seizures (BFNS) to sporadic cases of severe epileptic and developmental encephalopathy (DEE). Here, we describe a patient with neonatal onset DEE, carrying a previously undescribed heterozygous KCNQ2 c.418G > C, p.Glu140Gln (E140Q) variant. Patch-clamp recordings in CHO cells expressing the E140Q mutation reveal dramatic loss of function (LoF) effects. Multistate structural modelling suggested that the E140Q substitution impeded an intrasubunit electrostatic interaction occurring between the E140 side chain in S2 and the arginine at position 210 in S4 (R210); this interaction is critically involved in stabilizing the activated configuration of the voltage-sensing domain (VSD) of Kv7.2. Functional results from coupled charge reversal or disulfide trapping experiments supported such a hypothesis. Finally, retigabine restored mutation-induced functional changes, reinforcing the rationale for the clinical use of Kv7 activators as personalized therapy for DEE-affected patients carrying Kv7.2 LoF mutations.
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25
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Sands TT, Miceli F, Lesca G, Beck AE, Sadleir LG, Arrington DK, Schönewolf-Greulich B, Moutton S, Lauritano A, Nappi P, Soldovieri MV, Scheffer IE, Mefford HC, Stong N, Heinzen EL, Goldstein DB, Perez AG, Kossoff EH, Stocco A, Sullivan JA, Shashi V, Gerard B, Francannet C, Bisgaard AM, Tümer Z, Willems M, Rivier F, Vitobello A, Thakkar K, Rajan DS, Barkovich AJ, Weckhuysen S, Cooper EC, Taglialatela M, Cilio MR. Autism and developmental disability caused by KCNQ3 gain-of-function variants. Ann Neurol 2019; 86:181-192. [PMID: 31177578 DOI: 10.1002/ana.25522] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 06/03/2019] [Accepted: 06/06/2019] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Recent reports have described single individuals with neurodevelopmental disability (NDD) harboring heterozygous KCNQ3 de novo variants (DNVs). We sought to assess whether pathogenic variants in KCNQ3 cause NDD and to elucidate the associated phenotype and molecular mechanisms. METHODS Patients with NDD and KCNQ3 DNVs were identified through an international collaboration. Phenotypes were characterized by clinical assessment, review of charts, electroencephalographic (EEG) recordings, and parental interview. Functional consequences of variants were analyzed in vitro by patch-clamp recording. RESULTS Eleven patients were assessed. They had recurrent heterozygous DNVs in KCNQ3 affecting residues R230 (R230C, R230H, R230S) and R227 (R227Q). All patients exhibited global developmental delay within the first 2 years of life. Most (8/11, 73%) were nonverbal or had a few words only. All patients had autistic features, and autism spectrum disorder (ASD) was diagnosed in 5 of 11 (45%). EEGs performed before 10 years of age revealed frequent sleep-activated multifocal epileptiform discharges in 8 of 11 (73%). For 6 of 9 (67%) recorded between 1.5 and 6 years of age, spikes became near-continuous during sleep. Interestingly, most patients (9/11, 82%) did not have seizures, and no patient had seizures in the neonatal period. Voltage-clamp recordings of the mutant KCNQ3 channels revealed gain-of-function (GoF) effects. INTERPRETATION Specific GoF variants in KCNQ3 cause NDD, ASD, and abundant sleep-activated spikes. This new phenotype contrasts both with self-limited neonatal epilepsy due to KCNQ3 partial loss of function, and with the neonatal or infantile onset epileptic encephalopathies due to KCNQ2 GoF. ANN NEUROL 2019;86:181-192.
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Affiliation(s)
- Tristan T Sands
- Department of Neurology, Columbia University Medical Center, New York, NY.,Institute for Genomic Medicine, Columbia University Medical Center, New York, NY
| | - Francesco Miceli
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II,", Naples, Italy
| | - Gaetan Lesca
- Department of Medical Genetics, Reference Center for Developmental Anomalies, Civil Hospices of Lyon, Lyon, France.,French Institute of Health and Medical Research U1028, French National Center for Scientific Research UMR5292, Center for Research in Neuroscience in Lyon, Genetics of Neurodevelopment Team, Claude Bernard University Lyon 1, Lyon, France.,Claude Bernard University Lyon 1, Lyon, France
| | - Anita E Beck
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA.,Seattle Children's Hospital, Seattle, WA
| | - Lynette G Sadleir
- Department of Paediatrics and Child Health, University of Otago, Wellington, New Zealand
| | | | - Bitten Schönewolf-Greulich
- Center for Rett Syndrome, Department of Pediatrics and Adolescent Medicine, National Hospital, Copenhagen, Denmark.,Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Sébastien Moutton
- French Institute of Health and Medical Research U1231, Laboratory of Cognitive Neuroscience UMR1231, Genetics of Developmental Anomalies, Burgundy University, F-21000, Dijon, France
| | - Anna Lauritano
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II,", Naples, Italy
| | - Piera Nappi
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II,", Naples, Italy
| | - Maria Virginia Soldovieri
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - Ingrid E Scheffer
- University of Melbourne, Austin Health, Royal Children's Hospital, Florey and Murdoch Institutes, Melbourne, Victoria, Australia
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA
| | - Nicholas Stong
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY
| | - Erin L Heinzen
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY
| | - David B Goldstein
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY
| | - Ana Grijalvo Perez
- Department of Neurology, University of California, San Francisco, San Francisco, CA
| | - Eric H Kossoff
- Departments of Pediatrics and Neurology, Johns Hopkins School of Medicine, Baltimore, MD
| | - Amber Stocco
- Pediatric Neurology, INTEGRIS Baptist Medical Center, Oklahoma City, OK
| | - Jennifer A Sullivan
- Division of Medical Genetics, Department of Pediatrics, Duke University, Durham, NC
| | - Vandana Shashi
- Division of Medical Genetics, Department of Pediatrics, Duke University, Durham, NC
| | - Benedicte Gerard
- Molecular Genetic Unit, Strasbourg University Hospital, Strasbourg, France
| | - Christine Francannet
- Genetics Department, Reference Center for Developmental Anomalies, Clermont-Ferrand University Hospital, Clermont-Ferrand, France
| | - Anne-Marie Bisgaard
- Center for Rett Syndrome, Department of Pediatrics and Adolescent Medicine, National Hospital, Copenhagen, Denmark
| | - Zeynep Tümer
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marjolaine Willems
- Reference Center for Developmental Disorders, Department of Medical Genetics, Arnaud de Villeneuve Hospital, Montpellier University Hospital, Montpellier, France
| | - François Rivier
- Department of Pediatric Neurology, University Hospital of Montpellier, and Physiology and Experimental Medicine of Heart and Muscle Unit, University of Montpellier, National Institute for Health and Medical Research, French National Center for Scientific Research, Montpellier, France
| | - Antonio Vitobello
- Functional Unit 12, Innovation in Genomic Diagnosis of Rare Diseases, University Hospital Dijon-Bourgogne, Dijon, France
| | - Kavita Thakkar
- Division of Neurology, Department of Pediatrics, Children's Hospital of Pittsburgh and University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Deepa S Rajan
- Division of Neurology, Department of Pediatrics, Children's Hospital of Pittsburgh and University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - A James Barkovich
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Sarah Weckhuysen
- Neurogenetics Group, University of Antwerp, Antwerp, Belgium.,Neurology Department, University Hospital Antwerp, Antwerp, Belgium
| | - Edward C Cooper
- Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Maurizio Taglialatela
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II,", Naples, Italy
| | - M Roberta Cilio
- Department of Neurology, University of California, San Francisco, San Francisco, CA.,Departments of Pediatrics and Institute of Experimental and Clinical Research, University of Louvain, Brussels, Belgium
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26
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From molecules to medicines: the dawn of targeted therapies for genetic epilepsies. Nat Rev Neurol 2018; 14:735-745. [DOI: 10.1038/s41582-018-0099-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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27
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Zhang T, Todorovic MS, Williamson J, Kapur J. Flupirtine and diazepam combination terminates established status epilepticus: results in three rodent models. Ann Clin Transl Neurol 2017; 4:888-896. [PMID: 29296617 PMCID: PMC5740237 DOI: 10.1002/acn3.497] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/30/2017] [Accepted: 10/09/2017] [Indexed: 12/17/2022] Open
Abstract
Objective Status epilepticus (SE) is a neurological emergency requiring rapid termination of seizures. New treatment choices are needed for benzodiazepine-refractory SE or established SE (ESE). Previous studies have demonstrated that the potassium-channel opener flupirtine terminates seizures in neonatal animals. However, its effectiveness in adult ESE has not been tested. We tested whether flupirtine alone or in combination with the benzodiazepine diazepam would terminate ESE in three animal models. Methods SE was induced by administration of lithium followed by pilocarpine, by electrical stimulation of the hippocampus or by diisopropylfluorophosphate (DFP) administration. Seizures were assessed by EEG recorded from the hippocampus and cortex. Results Flupirtine alone did not terminate ESE within 60 min of administration in any of the three models of ESE. A combination of flupirtine and diazepam terminated ESE within 60 min in all the three models. The drug combination shortened the duration of ESE in all three models. Drug responsiveness was distinct between each model. Conclusion A combination of the potassium channel opener flupirtine and diazepam is a potential therapy for ESE.
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Affiliation(s)
- Terry Zhang
- Department of Neurology University of Virginia Health Sciences Center Charlottesville Virginia 22908
| | - Marko S Todorovic
- Department of Neurology University of Virginia Health Sciences Center Charlottesville Virginia 22908
| | - John Williamson
- Department of Neurology University of Virginia Health Sciences Center Charlottesville Virginia 22908
| | - Jaideep Kapur
- Department of Neurology University of Virginia Health Sciences Center Charlottesville Virginia 22908.,Department of Neuroscience University of Virginia Health Sciences Center Charlottesville Virginia 22908
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28
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Liu Y, Wang T, Liu X, Wei X, Xu T, Yin M, Ding X, Mo L, Chen L. Neuronal zinc-α2-glycoprotein is decreased in temporal lobe epilepsy in patients and rats. Neuroscience 2017; 357:56-66. [DOI: 10.1016/j.neuroscience.2017.05.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/22/2017] [Accepted: 05/23/2017] [Indexed: 12/13/2022]
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29
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Pellock JM, Arzimanoglou A, D'Cruz O, Holmes GL, Nordli D, Shinnar S. Extrapolating evidence of antiepileptic drug efficacy in adults to children ≥2 years of age with focal seizures: The case for disease similarity. Epilepsia 2017; 58:1686-1696. [PMID: 28755452 DOI: 10.1111/epi.13859] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2017] [Indexed: 12/18/2022]
Abstract
Expediting pediatric access to new antiseizure drugs is particularly compelling, because epileptic seizures are the most common serious neurological symptom in children. Analysis of antiepileptic drug (AED) efficacy outcomes of randomized controlled trials, conducted during the past 20 years in different populations and a broad range of study sites and countries, has shown considerable consistency for each drug between adult and pediatric populations. Historically, the majority of regulatory approvals for AEDs have been for seizure types and not for specific epilepsy syndromes. Available data, both anatomical and neurophysiological, support a similar pathophysiology of focal seizures in adults and young children, and suggest that by age 2 years the structural and physiological milieu upon which seizures develop is similar. Although the distribution of specific etiologies and epilepsy syndromes is different in children from in adults, this should not impact approvals of efficacy based on seizure type, because the pathophysiology of focal seizures and the drug responsiveness of these seizure types are quite similar. Safety and pharmacokinetics cannot be extrapolated from adults to children. The scientific rationale, clinical consensus, and published data support a future approach accepting efficacy data from adult trials and focusing exclusively on prospective pharmacokinetic, tolerability, and safety studies and long-term follow-up in children. Whereas tolerability studies can be compared easily in children and adults, safety studies require large numbers of patients followed for many years.
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Affiliation(s)
- John M Pellock
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia, U.S.A
| | - Alexis Arzimanoglou
- Department of Clinical Epileptology, Sleep Disorders, and Functional Pediatric Neurology, University Hospitals of Lyon, Lyon, France.,Epilepsy, Sleep, and Neurophysiology Section, Neurology Service, Hospital Sant Joan de Déu Barcelona, Barcelona, Spain
| | - O'Neill D'Cruz
- Consulting and Neurological Services, Chapel Hill, North Carolina, U.S.A
| | - Gregory L Holmes
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont, U.S.A
| | - Douglas Nordli
- Division of Pediatric Neurology, Children's Hospital Los Angeles, Keck School of Medicine of the University of Southern California, Los Angeles, California, U.S.A
| | - Shlomo Shinnar
- Departments of Neurology, Pediatrics, and Epidemiology and Population Health, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A
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30
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Sampath D, Valdez R, White AM, Raol YH. Anticonvulsant effect of flupirtine in an animal model of neonatal hypoxic-ischemic encephalopathy. Neuropharmacology 2017; 123:126-135. [PMID: 28587899 DOI: 10.1016/j.neuropharm.2017.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 05/07/2017] [Accepted: 06/02/2017] [Indexed: 12/20/2022]
Abstract
Research studies suggest that neonatal seizures, which are most commonly associated with hypoxic-ischemic injury, may contribute to brain injury and adverse neurologic outcome. Unfortunately, neonatal seizures are often resistant to treatment with current anticonvulsants. In the present study, we evaluated the efficacy of flupirtine, administered at clinically relevant time-points, for the treatment of neonatal seizures in an animal model of hypoxic-ischemic injury that closely replicates features of the human syndrome. We also compared the efficacy of flupirtine to that of phenobarbital, the current first-line drug for neonatal seizures. Flupirtine is a KCNQ potassium channel opener. KCNQ channels play an important role in controlling brain excitability during early development. In this study, hypoxic-ischemic injury was induced in neonatal rats, and synchronized video-EEG records were acquired at various time-points during the experiment to identify seizures. The results revealed that flupirtine, administered either 5 min after the first electroclinical seizure, or following completion of 2 h of hypoxia, i.e., during the immediate reperfusion period, reduced the number of rats with electroclinical seizures, and also the frequency and total duration of electroclinical seizures. Further, daily dosing of flupirtine decreased the seizure burden over 3 days following HI-induction, and modified the natural evolution of acute seizures. Moreover, compared to a therapeutic dose of phenobarbital, which was modestly effective against electroclinical seizures, flupirtine showed greater efficacy. Our results indicate that flupirtine is an extremely effective treatment for neonatal seizures in rats and provide evidence for a trial of this medication in newborn humans.
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Affiliation(s)
- Dayalan Sampath
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Robert Valdez
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Andrew M White
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Yogendra H Raol
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA.
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31
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Uchida T, Lossin C, Ihara Y, Deshimaru M, Yanagawa Y, Koyama S, Hirose S. Abnormal γ-aminobutyric acid neurotransmission in aKcnq2model of early onset epilepsy. Epilepsia 2017; 58:1430-1439. [DOI: 10.1111/epi.13807] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2015] [Indexed: 12/01/2022]
Affiliation(s)
- Taku Uchida
- Central Research Institute for the Pathomechanisms of Epilepsy; Fukuoka University; Fukuoka Japan
- Department of Neuroscience; Section of Integrative Physiology; Faculty of Medicine; University of Miyazaki; Miyazaki Japan
| | - Christoph Lossin
- Department of Neurology; University of California, Davis; Sacramento California U.S.A
| | - Yukiko Ihara
- Department of Pediatrics; Fukuoka University School of Medicine; Fukuoka Japan
| | - Masanobu Deshimaru
- Department of Chemistry; Faculty of Science; Fukuoka University; Fukuoka Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience; Gunma University Graduate School of Medicine; Maebashi Japan
| | - Susumu Koyama
- Department of Advanced Pharmacology; Daiichi University of Pharmacy; Fukuoka Japan
| | - Shinichi Hirose
- Central Research Institute for the Pathomechanisms of Epilepsy; Fukuoka University; Fukuoka Japan
- Department of Pediatrics; Fukuoka University School of Medicine; Fukuoka Japan
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A KCNQ2 E515D mutation associated with benign familial neonatal seizures and continuous spike and waves during slow-wave sleep syndrome in Taiwan. J Formos Med Assoc 2016; 116:711-719. [PMID: 28038823 DOI: 10.1016/j.jfma.2016.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 10/19/2016] [Accepted: 11/21/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND/PURPOSE Pediatric epilepsy caused by a KCNQ2 gene mutation usually manifests as benign familial neonatal seizures (BFNS) during the 1st week of life. However, the exact mechanism, phenotype, and genotype of the KCNQ2 mutation are unclear. METHODS We studied the KCNQ2 genotype from 75 nonconsanguineous patients with childhood epilepsy without an identified cause (age range: from 2 days to 18 years) and from 55 healthy adult controls without epilepsy. KCNQ2 mutation variants were transfected into HEK293 cells to investigate what functional changes they induced. RESULTS Four (5%) of the patients had the E515D KCNQ2 mutation, which the computer-based PolyPhen algorithm predicted to be deleterious. Their seizure outcomes were favorable, but three had an intellectual disability. Two patients with E515D presented with continuous spikes and waves during slow-wave sleep (CSWS), and the other two presented with BFNS. We also analyzed 10 affected family members with the same KCNQ2 mutation: all had epilepsy (8 had BFNS and 2 had CSWS). A functional analysis showed that the recordings of the E515D currents were significantly different (p<0.05), which suggested that channels with KCNQ2 E515D variants are less sensitive to voltage and require stronger depolarization to reach opening probabilities than those with the wild type or N780T (a benign polymorphism). CONCLUSION KCNQ2 mutations can cause various phenotypes in children: they lead to BFNS and CSWS. We hypothesize that patients with the KCNQ2 E515D mutation are susceptible to seizures.
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Frankel S, Medvedeva N, Gutherz S, Kulick C, Kondratyev A, Forcelli PA. Comparison of the long-term behavioral effects of neonatal exposure to retigabine or phenobarbital in rats. Epilepsy Behav 2016; 57:34-40. [PMID: 26921596 PMCID: PMC4828307 DOI: 10.1016/j.yebeh.2016.01.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 01/18/2023]
Abstract
Anticonvulsant drugs, when given during vulnerable periods of brain development, can have long-lasting consequences on nervous system function. In rats, the second postnatal week approximately corresponds to the late third trimester of gestation/early infancy in humans. Exposure to phenobarbital during this period has been associated with deficits in learning and memory, anxiety-like behavior, and social behavior, among other domains. Phenobarbital is the most common anticonvulsant drug used in neonatology. Several other drugs, such as lamotrigine, phenytoin, and clonazepam, have also been reported to trigger behavioral changes. A new generation anticonvulsant drug, retigabine, has not previously been evaluated for long-term effects on behavior. Retigabine acts as an activator of KCNQ channels, a mechanism that is unique among anticonvulsants. Here, we examined the effects retigabine exposure from postnatal day (P)7 to P14 on behavior in adult rats. We compared these effects with those produced by phenobarbital (as a positive control) and saline (as a negative control). Motor behavior was assessed by using the open field and rotarod, anxiety-like behavior by the open field, elevated plus maze, and light-dark transition task, and learning/memory by the passive avoidance task; social interactions were assessed in same-treatment pairs, and nociceptive sensitivity was assessed via the tail-flick assay. Motor behavior was unaltered by exposure to either drug. We found that retigabine exposure and phenobarbital exposure both induced increased anxiety-like behavior in adult animals. Phenobarbital, but not retigabine, exposure impaired learning and memory. These drugs also differed in their effects on social behavior, with retigabine-exposed animals displaying greater social interaction than phenobarbital-exposed animals. These results indicate that neonatal retigabine induces a subset of behavioral alterations previously described for other anticonvulsant drugs and extend our knowledge of drug-induced behavioral teratogenesis to a new mechanism of anticonvulsant action.
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Affiliation(s)
- Sari Frankel
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Natalia Medvedeva
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Samuel Gutherz
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Catherine Kulick
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Alexei Kondratyev
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Patrick A Forcelli
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States.
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Devaux J, Abidi A, Roubertie A, Molinari F, Becq H, Lacoste C, Villard L, Milh M, Aniksztejn L. A Kv7.2 mutation associated with early onset epileptic encephalopathy with suppression-burst enhances Kv7/M channel activity. Epilepsia 2016; 57:e87-93. [PMID: 27030113 DOI: 10.1111/epi.13366] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2016] [Indexed: 02/04/2023]
Abstract
Mutations in the KCNQ2 gene encoding the voltage-gated potassium channel subunit Kv7.2 cause early onset epileptic encephalopathy (EOEE). Most mutations have been shown to induce a loss of function or to affect the subcellular distribution of Kv7 channels in neurons. Herein, we investigated functional consequences and subcellular distribution of the p.V175L mutation of Kv7.2 (Kv7.2(V175L) ) found in a patient presenting EOEE. We observed that the mutation produced a 25-40 mV hyperpolarizing shift of the conductance-voltage relationship of both the homomeric Kv7.2(V175L) and heteromeric Kv7.2(V175L) /Kv7.3 channels compared to wild-type channels and a 10 mV hyperpolarizing shift of Kv7.2(V175L) /Kv7.2/Kv7.3 channels in a 1:1:2 ratio mimicking the patient situation. Mutant channels also displayed faster activation kinetics and an increased current density that was prevented by 1 μm linopirdine. The p.V175L mutation did not affect the protein expression of Kv7 channels and its localization at the axon initial segment. We conclude that p.V175L is a gain of function mutation. This confirms previous observations showing that mutations having opposite consequences on M channels can produce EOEE. These findings alert us that drugs aiming to increase Kv7 channel activity might have adverse effects in EOEE in the case of gain-of-function variants.
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Affiliation(s)
- Jérôme Devaux
- CNRS, Aix-Marseille University, CRN2M-UMR7286, Marseille, France
| | - Affef Abidi
- GMGF, Aix-Marseille University, Marseille, France.,INSERM, UMR_S 910, Marseille, France
| | - Agathe Roubertie
- Pediatric Neurology Department, Montpellier University Hospital, Montpellier, France.,INSERM U1051, INM Montpellier, Montpellier, France
| | - Florence Molinari
- Mediterranean Neurobiology Institute INMED, Aix-Marseille University, Marseille, France.,INSERM, UMR_S 901, Marseille, France
| | - Hélène Becq
- Mediterranean Neurobiology Institute INMED, Aix-Marseille University, Marseille, France.,INSERM, UMR_S 901, Marseille, France
| | - Caroline Lacoste
- GMGF, Aix-Marseille University, Marseille, France.,INSERM, UMR_S 910, Marseille, France.,Timone Children Hospital, Pediatric Neurology Department, APHM, Marseille, France
| | - Laurent Villard
- GMGF, Aix-Marseille University, Marseille, France.,INSERM, UMR_S 910, Marseille, France
| | - Mathieu Milh
- GMGF, Aix-Marseille University, Marseille, France.,INSERM, UMR_S 910, Marseille, France.,Timone Children Hospital, Pediatric Neurology Department, APHM, Marseille, France
| | - Laurent Aniksztejn
- Mediterranean Neurobiology Institute INMED, Aix-Marseille University, Marseille, France.,INSERM, UMR_S 901, Marseille, France
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Ihara Y, Tomonoh Y, Deshimaru M, Zhang B, Uchida T, Ishii A, Hirose S. Retigabine, a Kv7.2/Kv7.3-Channel Opener, Attenuates Drug-Induced Seizures in Knock-In Mice Harboring Kcnq2 Mutations. PLoS One 2016; 11:e0150095. [PMID: 26910900 PMCID: PMC4766199 DOI: 10.1371/journal.pone.0150095] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 02/09/2016] [Indexed: 12/30/2022] Open
Abstract
The hetero-tetrameric voltage-gated potassium channel Kv7.2/Kv7.3, which is encoded by KCNQ2 and KCNQ3, plays an important role in limiting network excitability in the neonatal brain. Kv7.2/Kv7.3 dysfunction resulting from KCNQ2 mutations predominantly causes self-limited or benign epilepsy in neonates, but also causes early onset epileptic encephalopathy. Retigabine (RTG), a Kv7.2/ Kv7.3-channel opener, seems to be a rational antiepileptic drug for epilepsies caused by KCNQ2 mutations. We therefore evaluated the effects of RTG on seizures in two strains of knock-in mice harboring different Kcnq2 mutations, in comparison to the effects of phenobarbital (PB), which is the first-line antiepileptic drug for seizures in neonates. The subjects were heterozygous knock-in mice (Kcnq2Y284C/+ and Kcnq2A306T/+) bearing the Y284C or A306T Kcnq2 mutation, respectively, and their wild-type (WT) littermates, at 63–100 days of age. Seizures induced by intraperitoneal injection of kainic acid (KA, 12mg/kg) were recorded using a video-electroencephalography (EEG) monitoring system. Effects of RTG on KA-induced seizures of both strains of knock-in mice were assessed using seizure scores from a modified Racine’s scale and compared with those of PB. The number and total duration of spike bursts on EEG and behaviors monitored by video recording were also used to evaluate the effects of RTG and PB. Both Kcnq2Y284C/+ and Kcnq2A306T/+ mice showed significantly more KA-induced seizures than WT mice. RTG significantly attenuated KA-induced seizure activities in both Kcnq2Y284C/+ and Kcnq2A306T/+ mice, and more markedly than PB. This is the first reported evidence of RTG ameliorating KA-induced seizures in knock-in mice bearing mutations of Kcnq2, with more marked effects than those observed with PB. RTG or other Kv7.2-channel openers may be considered as first-line antiepileptic treatments for epilepsies resulting from KCNQ2 mutations.
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Affiliation(s)
- Yukiko Ihara
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Yuko Tomonoh
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Masanobu Deshimaru
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Bo Zhang
- Department of Biochemistry, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Taku Uchida
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka City, Japan
| | - Atsushi Ishii
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Shinichi Hirose
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka City, Japan
- * E-mail:
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36
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Sun W, Liu J, Zhang C, Zhou N, Manohar S, Winchester W, Miranda JA, Salvi RJ. Potassium channel activator attenuates salicylate-induced cochlear hearing loss potentially ameliorating tinnitus. Front Neurol 2015; 6:77. [PMID: 25904892 PMCID: PMC4387930 DOI: 10.3389/fneur.2015.00077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/20/2015] [Indexed: 11/13/2022] Open
Abstract
High dose sodium salicylate causes moderate, reversible hearing loss and tinnitus. Salicylate-induced hearing loss is believed to arise from a reduction in the electromotile response of outer hair cells (OHCs) and/or reduction of KCNQ4 potassium currents in OHCs, which decreases the driving force for the transduction current. Therefore, enhancing OHC potassium currents could potentially prevent salicylate-induced temporary hearing loss. In this study, we tested whether opening voltage-gated potassium channels using ICA-105665, a novel small molecule that opens KCNQ2/3 and KCNQ3/5 channels, can reduce salicylate-induced hearing loss. We found that systemic application of ICA-105665 at 10 mg/kg prevented the salicylate-induced amplitude reduction and threshold shift in the compound action potentials recorded at the round window of the cochlea. ICA-105665 also prevented the salicylate-induced reduction of distortion-product otoacoustic emission. These results suggest that ICA-105665 partially compensates for salicylate-induced cochlear hearing loss by enhancing KCNQ2/3 and KCNQ3/5 potassium currents and the motility of OHCs.
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Affiliation(s)
- Wei Sun
- Center for Hearing and Deafness, State University of New York at Buffalo , Buffalo, NY , USA
| | - Jun Liu
- Department of Otolaryngology, General Hospital of PLA , Beijing , China
| | - Chao Zhang
- Department of Otolaryngology, General Hospital of PLA , Beijing , China
| | - Na Zhou
- Department of Otolaryngology, Peking University Third Hospital , Beijing , China
| | - Senthilvelan Manohar
- Center for Hearing and Deafness, State University of New York at Buffalo , Buffalo, NY , USA
| | | | | | - Richard J Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo , Buffalo, NY , USA
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Lv J, Cui W, Liu H, He H, Xiu Y, Guo J, Liu H, Liu Q, Zeng T, Chen Y, Zhang Y, Wu Q. Identification and characterization of long non-coding RNAs related to mouse embryonic brain development from available transcriptomic data. PLoS One 2013; 8:e71152. [PMID: 23967161 PMCID: PMC3743905 DOI: 10.1371/journal.pone.0071152] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 06/21/2013] [Indexed: 11/18/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) as a key group of non-coding RNAs have gained widely attention. Though lncRNAs have been functionally annotated and systematic explored in higher mammals, few are under systematical identification and annotation. Owing to the expression specificity, known lncRNAs expressed in embryonic brain tissues remain still limited. Considering a large number of lncRNAs are only transcribed in brain tissues, studies of lncRNAs in developmental brain are therefore of special interest. Here, publicly available RNA-sequencing (RNA-seq) data in embryonic brain are integrated to identify thousands of embryonic brain lncRNAs by a customized pipeline. A significant proportion of novel transcripts have not been annotated by available genomic resources. The putative embryonic brain lncRNAs are shorter in length, less spliced and show less conservation than known genes. The expression of putative lncRNAs is in one tenth on average of known coding genes, while comparable with known lncRNAs. From chromatin data, putative embryonic brain lncRNAs are associated with active chromatin marks, comparable with known lncRNAs. Embryonic brain expressed lncRNAs are also indicated to have expression though not evident in adult brain. Gene Ontology analysis of putative embryonic brain lncRNAs suggests that they are associated with brain development. The putative lncRNAs are shown to be related to possible cis-regulatory roles in imprinting even themselves are deemed to be imprinted lncRNAs. Re-analysis of one knockdown data suggests that four regulators are associated with lncRNAs. Taken together, the identification and systematic analysis of putative lncRNAs would provide novel insights into uncharacterized mouse non-coding regions and the relationships with mammalian embryonic brain development.
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Affiliation(s)
- Jie Lv
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Wei Cui
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Hongbo Liu
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Hongjuan He
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Youcheng Xiu
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Jing Guo
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Hui Liu
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Qi Liu
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Tiebo Zeng
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Yan Chen
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Yan Zhang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Qiong Wu
- School of Life Science and Technology, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
- * E-mail:
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38
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Maslarova A, Salar S, Lapilover E, Friedman A, Veh RW, Heinemann U. Increased susceptibility to acetylcholine in the entorhinal cortex of pilocarpine-treated rats involves alterations in KCNQ channels. Neurobiol Dis 2013; 56:14-24. [DOI: 10.1016/j.nbd.2013.02.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 02/19/2013] [Accepted: 02/25/2013] [Indexed: 02/03/2023] Open
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Li P, Zhu J, Kong Q, Jiang B, Wan X, Yue J, Li M, Jiang H, Li J, Gao Z. The ethylene bis-dithiocarbamate fungicide Mancozeb activates voltage-gated KCNQ2 potassium channel. Toxicol Lett 2013; 219:211-7. [DOI: 10.1016/j.toxlet.2013.03.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 03/15/2013] [Accepted: 03/20/2013] [Indexed: 10/27/2022]
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40
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Fister P, Soltirovska-Salamon A, Debeljak M, Paro-Panjan D. Benign familial neonatal convulsions caused by mutation in KCNQ3, exon 6: a European case. Eur J Paediatr Neurol 2013; 17:308-10. [PMID: 23146207 DOI: 10.1016/j.ejpn.2012.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 03/11/2012] [Accepted: 10/21/2012] [Indexed: 11/18/2022]
Abstract
Benign familial neonatal convulsions (BFNC) is a rare, clinically and genetically heterogenous epileptic disorder. Two voltage gated potassium genes, KCNQ2 and KCNQ3, have been identified as genes responsible for BFNC1 and BFNC2 respectively. While as many as 73 mutations of KCNQ2 have been described up to date, only 4 mutations in KCNQ3, 3 of them appearing in exon 5, have been identified. Mutation in exon 6 was found for the first time in a Chinese family, and here we report the same missense mutation of KCNQ3 within exon 6 in a Caucasian family, whose history and clinical picture were in accordance with BFNC.
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Affiliation(s)
- Petja Fister
- Department of Neonatology, University Children's Hospital, University Medical Centre, Bohoričeva ulica 20, Ljubljana, Slovenia
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41
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Blumkin L, Suls A, Deconinck T, De Jonghe P, Linder I, Kivity S, Dabby R, Leshinsky-Silver E, Lev D, Lerman-Sagie T. Neonatal seizures associated with a severe neonatal myoclonus like dyskinesia due to a familial KCNQ2 gene mutation. Eur J Paediatr Neurol 2012; 16:356-60. [PMID: 22169383 DOI: 10.1016/j.ejpn.2011.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 11/09/2011] [Accepted: 11/20/2011] [Indexed: 10/14/2022]
Abstract
UNLABELLED Mutations in the potassium channel gene KCNQ2, usually cause benign familial neonatal epilepsy. This is an autosomal dominant disorder characterized by clusters of seizures occurring in the first days of life. Most patients have normal psychomotor development and spontaneous remission of seizures by 12 months of age. Since Rett and Teubel reported the first family in 1964 and the identification of KCNQ2 gene mutations in this family by Zimprich et al. in 2006, phenotypic variability has been recognized including: later onset of seizures, myokymia in isolation or accompanied by seizures, neurological deficit and mental retardation. We report a mother and son with an atypical presentation of familial neonatal epilepsy. The mother has persistent epilepsy and subnormal intelligence. The son developed a severe dyskinesia clinically compatible with multifocal myoclonus in the neonatal period that only responded to carbamazepine. He also has ataxia and delayed psychomotor development. EMG revealed a spontaneous occurrence of repetitive normal motor potentials in different muscle groups. Genetic analysis identified a heterozygous missense mutation in KCNQ2 in the child and his mother. CONCLUSION KCNQ2 mutations can present with a neonatal onset multifocal myoclonus-like dyskinesia.
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Affiliation(s)
- Lubov Blumkin
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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Sun J, Kapur J. M-type potassium channels modulate Schaffer collateral-CA1 glutamatergic synaptic transmission. J Physiol 2012; 590:3953-64. [PMID: 22674722 DOI: 10.1113/jphysiol.2012.235820] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Previous studies have suggested that muscarinic receptor activation modulates glutamatergic transmission. M-type potassium channels mediate the effects of muscarinic activation in the hippocampus, and it has been proposed that they modulate glutamatergic synaptic transmission. We tested whether M1 muscarinic receptor activation enhances glutamatergic synaptic transmission via the inhibition of the M-type potassium channels that are present in Schaffer collateral axons and terminals. Miniature excitatory postsynaptic currents (mEPSCs) were recorded from CA1 pyramidal neurons. The M1 receptor agonist, NcN-A-343, increased the frequency of mEPSCs, but did not alter their amplitude. The M-channel blocker XE991 and its analogue linopirdine also increased the frequency of mEPSCs. Flupirtine, which opens M-channels, had the opposite effect. XE991 did not enhance mEPSCs frequency in a calcium-free external medium. Blocking P/Q- and N-type calcium channels abolished the effect of XE991 on mEPSCs. These data suggested that the inhibition of M-channels increases presynaptic calcium-dependent glutamate release in CA1 pyramidal neurons. The effects of these agents on the membrane potentials of presynaptic CA3 pyramidal neurons were studied using current clamp recordings; activation of M1 receptors and blocking M-channels depolarized neurons and increased burst firing. The input resistance of CA3 neurons was increased by the application of McN-A-343 and XE991; these effects were consistent with the closure of M-channels. Muscarinic activation inhibits M-channels in CA3 pyramidal neurons and its efferents – Schaffer collateral, which causes the depolarization, activates voltage-gated calcium channels, and ultimately elevates the intracellular calcium concentration to increase the release of glutamate on CA1 pyramidal neurons.
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Affiliation(s)
- Jianli Sun
- Department of Neurology, Box 800394, University of Virginia-HSC, Charlottesville, VA 22908, USA
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Chege SW, Hortopan GA, T Dinday M, Baraban SC. Expression and function of KCNQ channels in larval zebrafish. Dev Neurobiol 2012; 72:186-98. [PMID: 21692188 DOI: 10.1002/dneu.20937] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Members of the K(v)7 family generate a subthreshold potassium current, termed M-current, that regulates the excitability of principal central neurons. Mutations in two members of this family, K(v)7.2 (KCNQ2) and K(v)7.3 (KCNQ3) are associated with a neurological disorder known as benign familial neonatal convulsion (BFNC). Despite their importance in normal and pathological brain function, developmental expression and function of these channels remains relatively unexplored. Here, we examined the temporal expression of K(v)7 channel subunits in zebrafish larvae using a real-time quantitative PCR approach. Spatial expression in the larval zebrafish brain was assessed using whole-mount in situ hybridization. The mRNA for three members of the K(v)7 family (KCNQ2, 3 and 5) is reported in zebrafish between two and seven days post-fertilization (dpf). Using electrophysiological techniques, we show that inhibitors of K(v)7 channels (linopirdine and XE991) induce burst discharge activity in immature zebrafish between 3 and 7 dpf. This abnormal electrical activity is blocked by a K(v)7 channel opener (retigabine) and was also shown to evoke convulsive behaviors in freely swimming zebrafish. Using morpholino oligonucleotides directed against KCNQ3, we confirmed a role for KCNQ channels in generation of electrical burst discharges. These results indicate that functional K(v)7 channels are expressed in the larval zebrafish nervous system and could play a direct role in generation of seizure activity.
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Affiliation(s)
- Sally W Chege
- PIBS Graduate Program in Neuroscience, University of California, San Francisco, San Francisco, California 94143, USA
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44
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The genetics of monogenic idiopathic epilepsies and epileptic encephalopathies. Seizure 2011; 21:3-11. [PMID: 21917483 DOI: 10.1016/j.seizure.2011.08.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 08/06/2011] [Accepted: 08/09/2011] [Indexed: 12/23/2022] Open
Abstract
The group of idiopathic epilepsies encompasses numerous syndromes without known organic substrate. Genetic anomalies are thought to be responsible for pathogenesis, with a monogenic or polygenic model of inheritance. Over the last two decades, a number of genetic anomalies and encoded proteins have been related to particular idiopathic epilepsies and epileptic encephalopathies. Most of these mutations involve subunits of neuronal ion channels (e.g. potassium, sodium, and chloride channels), and may result in abnormal neuronal hyperexcitability manifesting with seizures. However non-ion channel proteins may also be affected. Correlations between genotype and phenotype are not easy to establish, since genetic and non-genetic factors are likely to play a role in determining the severity of clinical features. The growing number of discoveries on this topic are improving classification, prognosis and counseling of patients and families with these forms of epilepsy, and may lead to targeted therapeutic approaches in the near future. In this article the authors have reviewed the main genetic discoveries in the field of the monogenic idiopathic epilepsies and epileptic encephalopathies, in order to provide epileptologists with a concise and comprehensive summary of clinical and genetic features of these seizure disorders.
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Wang W, Takashima S, Segawa Y, Itoh M, Shi X, Hwang SK, Nabeshima K, Takeshita M, Hirose S. The developmental changes of Na(v)1.1 and Na(v)1.2 expression in the human hippocampus and temporal lobe. Brain Res 2011; 1389:61-70. [PMID: 21377452 DOI: 10.1016/j.brainres.2011.02.083] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 02/24/2011] [Accepted: 02/25/2011] [Indexed: 01/01/2023]
Abstract
Alterations of the genes encoding α1 and α2 subunits of voltage-gated sodium channels (SCN1A, SCN2A) have been reported as causes of various types of epilepsy, most of which occur during the first year of life; as yet, however, the detailed mechanisms are unclear. We suppose that developmental changes of SCN1A and SCN2A in the human brain, which are unknown yet, may play an important role. So here, we studied the developmental changes of their corresponding proteins (Na(v)1.1 and Na(v)1.2) in the human hippocampus and temporal lobe in 28 autopsy cases, which age from 13weeks of gestation (GW) to 63years of age (Y). Using comparative microscopic immunohistochemical (IHC) analysis, we found that Na(v)1.1 and Na(v)1.2 immunoreactivity first appeared at 19GW, simultaneously in the hippocampus and the white matter of temporal lobe. In nearly all age groups, Na(v)1.1 immunoreactivity was weak and relatively homogeneous. In general, Na(v)1.1 immunoreactive (IR) neurons and neurites increased during the late fetal and postnatal periods, reached their peaks 7-9months after birth (M), then decreased and remained stable at a relatively low level during childhood and adulthood. On the other hand, Na(v)1.2 immunoreactivity was strong and heterogeneous. In the hippocampus, Na(v)1.2 IR neurons increased gradually during the late fetal period, reached their peaks at 7-9M, sustained this high level during childhood, and then decreased slightly at adulthood. In the temporal lobe, Na(v)1.2 IR neurons reached a high level during the late fetal period, and maintained that level during subsequent developmental stages; Na(v)1.2 IR neurites also increased to a relatively high level during the late fetal period and continued to increase up to and during adulthood. Using double-staining IHC, we found that Na(v)1.1 and Na(v)1.2 had a relatively high colocalization rate with parvalbumin and showed distinct developmental changes. These findings extend our previous understanding of sodium channels and may help us discover the pathomechanisms of sodium channel-related age-dependent epilepsy.
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Affiliation(s)
- Wenze Wang
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
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46
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Zappella M. Autistic regression with and without EEG abnormalities followed by favourable outcome. Brain Dev 2010; 32:739-45. [PMID: 20708360 DOI: 10.1016/j.braindev.2010.05.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 05/12/2010] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To explore the relationship between autistic regression (AR) with and without EEG abnormalities and favourable outcome. METHODS Follow up data on children with favourable outcome in a series of 534 cases aged below 5 years and diagnosed as ASD. RESULTS Cases with regression were 167 (31.8%), usually with persistent ASD, intellectual disabilities and EEG abnormalities. Thirty nine children (7.3%) went off autism and recovered entirely their intellectual and social abilities. Few of them included examples of pharmacologically treated Landau and Kleffner syndrome and other similar complex cases with abnormal EEG. The majority was represented by 36 (6.7%) children, mostly males, with a dysmaturational syndrome: their development was initially normal up to 18 months when an autistic regression occurred accompanied by the appearance of motor and vocal tics. Relational therapies were followed by rapid improvement. By 6 years all children had lost features of ASD and their I.Q. was in most cases between 90 and 110. Convulsions were absent and EEG was normal in all cases except one. In a few of them recovery was spontaneous. Seventeen children were followed after 5 years 6 months: 12 (70%) had ADHD, 10 (56%) persistent tics. Tics were often present in parents and relatives, ASD absent, suggesting a genetic background different from cases with persistent ASD. With one exception all "off autism" children had a previous autistic regression. CONCLUSIONS In this series "off autism" children had either early onset epilepsy and/or EEG abnormalities or cases of dysmaturational syndrome. Autistic regression was present in almost all.
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Yum MS, Ko TS, Yoo HW. The first Korean case of KCNQ2 mutation in a family with benign familial neonatal convulsions. J Korean Med Sci 2010; 25:324-6. [PMID: 20119593 PMCID: PMC2811307 DOI: 10.3346/jkms.2010.25.2.324] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 08/23/2008] [Indexed: 12/02/2022] Open
Abstract
Neonatal seizures represent a heterogeneous group of disorders with vastly different etiologies and outcomes. Benign familial neonatal convulsions (BFNC) are a distinctive epileptic syndrome of autosomal dominant inheritance with a favorable prognosis, characterized by the occurrence of unprovoked partial or generalized clonic seizures in the neonatal period or early infancy. Recently, mutations in two potassium channel genes, KCNQ2 and KCNQ3, have been described in this disorder. In this report, we describe a family with BFNC due to a KCNQ2 mutation, the first such family to be described in the Korean population. The diagnosis of BFNC can be made based on clinical suspicion and careful history taking with special emphasis on the familial nature of the disorder. KCNQ2 mutations may be associated with BFNC in a number of different races, as has been reported in other ethnic groups.
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Affiliation(s)
- Mi-Sun Yum
- Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Tae-Sung Ko
- Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Han-Wook Yoo
- Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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Functional analysis of novel KCNQ2 mutations found in patients with Benign Familial Neonatal Convulsions. Neurosci Lett 2009; 462:24-9. [PMID: 19559753 DOI: 10.1016/j.neulet.2009.06.064] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 06/19/2009] [Accepted: 06/19/2009] [Indexed: 12/16/2022]
Abstract
Benign Familial Neonatal Convulsions (BFNC) are a rare epilepsy disorder with an autosomal-dominant inheritance. It is linked to mutations in the potassium channel genes KCNQ2 and KCNQ3. These encode for Kv7.2 and Kv7.3 potassium ion channels, which produce an M-current that regulates the potential firing action in neurons through modulation of the membrane potential. We report on the biophysical and biochemical properties of V589X, T359K and P410fs12X mutant-KCNQ2 ion channels that were detected in three BFNC families. Mutant KCNQ2 cDNAs were co-expressed with WT-KCNQ2 and KCNQ3 cDNAs in HEK293 cells to mimic heterozygous expression of the KCNQ2 mutations in BFNC patients. The resulting potassium currents were measured using patch-clamp techniques and showed an approximately 75% reduction in current and a depolarized shift in the voltage dependence of activation. Furthermore, the time-constant of activation of M-currents in cells expressing T359K and P410fs12X was slower compared to cells expressing only wild-type proteins. Immunofluorescent labeling of HEK293 cells stably expressing GFP-tagged KCNQ2-WT or mutant alpha-subunits indicated cell surface expression of WT, V589X and T359K mutants, suggesting a loss-of-function, while P410fs12X was predominantly retained in the ER and sub-cellular compartments outside the ER suggesting an effectively haplo-insufficient effect.
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49
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Mechanisms of human inherited epilepsies. Prog Neurobiol 2009; 87:41-57. [DOI: 10.1016/j.pneurobio.2008.09.016] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 08/25/2008] [Accepted: 09/29/2008] [Indexed: 12/19/2022]
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50
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Bender RA, Baram TZ. Hyperpolarization activated cyclic-nucleotide gated (HCN) channels in developing neuronal networks. Prog Neurobiol 2008; 86:129-40. [PMID: 18834920 PMCID: PMC2606691 DOI: 10.1016/j.pneurobio.2008.09.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 07/24/2008] [Accepted: 09/04/2008] [Indexed: 12/23/2022]
Abstract
Developing neuronal networks evolve continuously, requiring that neurons modulate both their intrinsic properties and their responses to incoming synaptic signals. Emerging evidence supports roles for the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in this neuronal plasticity. HCN channels seem particularly suited for fine-tuning neuronal properties and responses because of their remarkably large and variable repertoire of functions, enabling integration of a wide range of cellular signals. Here, we discuss the involvement of HCN channels in cortical and hippocampal network maturation, and consider potential roles of developmental HCN channel dysregulation in brain disorders such as epilepsy.
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Affiliation(s)
- Roland A. Bender
- Institute of Anatomy I, University of Hamburg, D-20246 Hamburg, Germany, Phone: +49-40-428034333, Fax: +49-40-428034966, E-mail:
| | - Tallie Z. Baram
- Departments Anatomy/Neurobiology, Pediatrics & Neurology, University of California, Irvine, CA 92697-4475, USA, Phone: +1-949-824-3307, Fax: +1-949-824-1106, E-mail:
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