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Maraslioglu-Sperber A, Pizzi E, Fisch JO, Kattler K, Ritter T, Friauf E. Molecular and functional profiling of cell diversity and identity in the lateral superior olive, an auditory brainstem center with ascending and descending projections. Front Cell Neurosci 2024; 18:1354520. [PMID: 38846638 PMCID: PMC11153811 DOI: 10.3389/fncel.2024.1354520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/15/2024] [Indexed: 06/09/2024] Open
Abstract
The lateral superior olive (LSO), a prominent integration center in the auditory brainstem, contains a remarkably heterogeneous population of neurons. Ascending neurons, predominantly principal neurons (pLSOs), process interaural level differences for sound localization. Descending neurons (lateral olivocochlear neurons, LOCs) provide feedback into the cochlea and are thought to protect against acoustic overload. The molecular determinants of the neuronal diversity in the LSO are largely unknown. Here, we used patch-seq analysis in mice at postnatal days P10-12 to classify developing LSO neurons according to their functional and molecular profiles. Across the entire sample (n = 86 neurons), genes involved in ATP synthesis were particularly highly expressed, confirming the energy expenditure of auditory neurons. Two clusters were identified, pLSOs and LOCs. They were distinguished by 353 differentially expressed genes (DEGs), most of which were novel for the LSO. Electrophysiological analysis confirmed the transcriptomic clustering. We focused on genes affecting neuronal input-output properties and validated some of them by immunohistochemistry, electrophysiology, and pharmacology. These genes encode proteins such as osteopontin, Kv11.3, and Kvβ3 (pLSO-specific), calcitonin-gene-related peptide (LOC-specific), or Kv7.2 and Kv7.3 (no DEGs). We identified 12 "Super DEGs" and 12 genes showing "Cluster similarity." Collectively, we provide fundamental and comprehensive insights into the molecular composition of individual ascending and descending neurons in the juvenile auditory brainstem and how this may relate to their specific functions, including developmental aspects.
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Affiliation(s)
- Ayse Maraslioglu-Sperber
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Erika Pizzi
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Jonas O. Fisch
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Kathrin Kattler
- Genetics/Epigenetics Group, Department of Biological Sciences, Saarland University, Saarbrücken, Germany
| | - Tamara Ritter
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Eckhard Friauf
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
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Talucci I, Arlt FA, Kreissner KO, Nasouti M, Wiessler AL, Miske R, Mindorf S, Dettmann I, Moniri M, Bayer M, Broegger Christensen P, Ayzenberg I, Kraft A, Endres M, Komorowski L, Villmann C, Doppler K, Prüss H, Maric HM. Molecular dissection of an immunodominant epitope in K v1.2-exclusive autoimmunity. Front Immunol 2024; 15:1329013. [PMID: 38665908 PMCID: PMC11043588 DOI: 10.3389/fimmu.2024.1329013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/22/2024] [Indexed: 04/28/2024] Open
Abstract
Introduction Subgroups of autoantibodies directed against voltage-gated potassium channel (Kv) complex components have been associated with immunotherapy-responsive clinical syndromes. The high prevalence and the role of autoantibodies directly binding Kv remain, however, controversial. Our objective was to determine Kv autoantibody binding requirements and to clarify their contribution to the observed immune response. Methods Binding epitopes were studied in sera (n = 36) and cerebrospinal fluid (CSF) (n = 12) from a patient cohort positive for Kv1.2 but negative for 32 common neurological autoantigens and controls (sera n = 18 and CSF n = 5) by phospho and deep mutational scans. Autoantibody specificity and contribution to the observed immune response were resolved on recombinant cells, cerebellum slices, and nerve fibers. Results 83% of the patients (30/36) within the studied cohort shared one out of the two major binding epitopes with Kv1.2-3 reactivity. Eleven percent (4/36) of the serum samples showed no binding. Fingerprinting resolved close to identical sequence requirements for both shared epitopes. Kv autoantibody response is directed against juxtaparanodal regions in peripheral nerves and the axon initial segment in central nervous system neurons and exclusively mediated by the shared epitopes. Discussion Systematic mapping revealed two shared autoimmune responses, with one dominant Kv1.2-3 autoantibody epitope being unexpectedly prevalent. The conservation of the molecular binding requirements among these patients indicates a uniform autoantibody repertoire with monospecific reactivity. The enhanced sensitivity of the epitope-based (10/12) compared with that of the cell-based detection (7/12) highlights its use for detection. The determined immunodominant epitope is also the primary immune response visible in tissue, suggesting a diagnostic significance and a specific value for routine screening.
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Affiliation(s)
- Ivan Talucci
- Rudolf Virchow Center for Integrative and Translational Bioimaging; University of Würzburg, Würzburg, Germany
- Department of Neurology, University Hospital Würzburg, Würzburg, Germany
| | - Friederike A. Arlt
- Department of Neurology and Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Kai O. Kreissner
- Rudolf Virchow Center for Integrative and Translational Bioimaging; University of Würzburg, Würzburg, Germany
| | - Mahoor Nasouti
- Rudolf Virchow Center for Integrative and Translational Bioimaging; University of Würzburg, Würzburg, Germany
- Department of Neurology and Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, Berlin, Germany
| | - Anna-Lena Wiessler
- Institute for Clinical Neurobiology, University of Wuerzburg, Würzburg, Germany
| | - Ramona Miske
- Institute for Experimental Immunology, affiliated to EUROIMMUN Medizinische Labordiagnostika AG, Lübeck, Germany
| | - Swantje Mindorf
- Institute for Experimental Immunology, affiliated to EUROIMMUN Medizinische Labordiagnostika AG, Lübeck, Germany
| | - Inga Dettmann
- Institute for Experimental Immunology, affiliated to EUROIMMUN Medizinische Labordiagnostika AG, Lübeck, Germany
| | - Mehrnaz Moniri
- Rudolf Virchow Center for Integrative and Translational Bioimaging; University of Würzburg, Würzburg, Germany
| | - Markus Bayer
- Rudolf Virchow Center for Integrative and Translational Bioimaging; University of Würzburg, Würzburg, Germany
| | | | - Ilya Ayzenberg
- Department of Neurology, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Andrea Kraft
- Department of Neurology, Hospital Martha-Maria, Halle, Germany
| | - Matthias Endres
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- Klinik und Hochschulambulanz für Neurologie, Charité-Universitätsmedizin, Berlin, Germany
- Center for Stroke Research, Berlin, Germany
- German Centre for Cardiovascular Research (DZHK), Berlin, Germany
- German Center for Mental Health (DZPG), Berlin, Germany
| | - Lars Komorowski
- Institute for Experimental Immunology, affiliated to EUROIMMUN Medizinische Labordiagnostika AG, Lübeck, Germany
| | - Carmen Villmann
- Institute for Clinical Neurobiology, University of Wuerzburg, Würzburg, Germany
| | - Kathrin Doppler
- Department of Neurology, University Hospital Würzburg, Würzburg, Germany
| | - Harald Prüss
- Department of Neurology and Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Hans M. Maric
- Rudolf Virchow Center for Integrative and Translational Bioimaging; University of Würzburg, Würzburg, Germany
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Zhao R, Qasim A, Sophanpanichkul P, Dai H, Nayak M, Sher I, Chill J, Goldstein SAN. Selective block of human Kv1.1 channels and an epilepsy-associated gain-of-function mutation by AETX-K peptide. FASEB J 2024; 38:e23381. [PMID: 38102952 PMCID: PMC10754259 DOI: 10.1096/fj.202302061r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/11/2023] [Accepted: 12/05/2023] [Indexed: 12/17/2023]
Abstract
Dysfunction of the human voltage-gated K+ channel Kv1.1 has been associated with epilepsy, multiple sclerosis, episodic ataxia, myokymia, and cardiorespiratory dysregulation. We report here that AETX-K, a sea anemone type I (SAK1) peptide toxin we isolated from a phage display library, blocks Kv1.1 with high affinity (Ki ~ 1.6 pM) and notable specificity, inhibiting other Kv channels we tested a million-fold less well. Nuclear magnetic resonance (NMR) was employed both to determine the three-dimensional structure of AETX-K, showing it to employ a classic SAK1 scaffold while exhibiting a unique electrostatic potential surface, and to visualize AETX-K bound to the Kv1.1 pore domain embedded in lipoprotein nanodiscs. Study of Kv1.1 in Xenopus oocytes with AETX-K and point variants using electrophysiology demonstrated the blocking mechanism to employ a toxin-channel configuration we have described before whereby AETX-K Lys23 , two positions away on the toxin interaction surface from the classical blocking residue, enters the pore deeply enough to interact with K+ ions traversing the pathway from the opposite side of the membrane. The mutant channel Kv1.1-L296 F is associated with pharmaco-resistant multifocal epilepsy in infants because it significantly increases K+ currents by facilitating opening and slowing closure of the channels. Consistent with the therapeutic potential of AETX-K for Kv1.1 gain-of-function-associated diseases, AETX-K at 4 pM decreased Kv1.1-L296 F currents to wild-type levels; further, populations of heteromeric channels formed by co-expression Kv1.1 and Kv1.2, as found in many neurons, showed a Ki of ~10 nM even though homomeric Kv1.2 channels were insensitive to the toxin (Ki > 2000 nM).
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Affiliation(s)
- Ruiming Zhao
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Arwa Qasim
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Punyanuch Sophanpanichkul
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Hui Dai
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Maha Nayak
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Inbal Sher
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Jordan Chill
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Steve A. N. Goldstein
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
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Borowicz-Reutt K, Czernia J, Krawczyk M. Genetic Background of Epilepsy and Antiepileptic Treatments. Int J Mol Sci 2023; 24:16280. [PMID: 38003469 PMCID: PMC10671416 DOI: 10.3390/ijms242216280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Advanced identification of the gene mutations causing epilepsy syndromes is expected to translate into faster diagnosis and more effective treatment of these conditions. Over the last 5 years, approximately 40 clinical trials on the treatment of genetic epilepsies have been conducted. As a result, some medications that are not regular antiseizure drugs (e.g., soticlestat, fenfluramine, or ganaxolone) have been introduced to the treatment of drug-resistant seizures in Dravet, Lennox-Gastaut, maternally inherited chromosome 15q11.2-q13.1 duplication (Dup 15q) syndromes, and protocadherin 19 (PCDH 19)-clusterig epilepsy. And although the effects of soticlestat, fenfluramine, and ganaxolone are described as promising, they do not significantly affect the course of the mentioned epilepsy syndromes. Importantly, each of these syndromes is related to mutations in several genes. On the other hand, several mutations can occur within one gene, and different gene variants may be manifested in different disease phenotypes. This complex pattern of inheritance contributes to rather poor genotype-phenotype correlations. Hence, the detection of a specific mutation is not synonymous with a precise diagnosis of a specific syndrome. Bearing in mind that seizures develop as a consequence of the predominance of excitatory over inhibitory processes, it seems reasonable that mutations in genes encoding sodium and potassium channels, as well as glutamatergic and gamma-aminobutyric (GABA) receptors, play a role in the pathogenesis of epilepsy. In some cases, different pathogenic variants of the same gene can result in opposite functional effects, determining the effectiveness of therapy with certain medications. For instance, seizures related to gain-of-function (GoF) mutations in genes encoding sodium channels can be successfully treated with sodium channel blockers. On the contrary, the same drugs may aggravate seizures related to loss-of-function (LoF) variants of the same genes. Hence, knowledge of gene mutation-treatment response relationships facilitates more favorable selection of drugs for anticonvulsant therapy.
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Affiliation(s)
- Kinga Borowicz-Reutt
- Independent Unit of Experimental Neuropathophysiology, Department of Toxicology, Medical University of Lublin, Jaczewskiego 8b, 20-090 Lublin, Poland; (J.C.); (M.K.)
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Kodirov SA. Adam, amigo, brain, and K channel. Biophys Rev 2023; 15:1393-1424. [PMID: 37975011 PMCID: PMC10643815 DOI: 10.1007/s12551-023-01163-5] [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: 05/02/2023] [Accepted: 09/28/2023] [Indexed: 11/19/2023] Open
Abstract
Voltage-dependent K+ (Kv) channels are diverse, comprising the classical Shab - Kv2, Shaker - Kv1, Shal - Kv4, and Shaw - Kv3 families. The Shaker family alone consists of Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv1.5, Kv1.6, and Kv1.7. Moreover, the Shab family comprises two functional (Kv2.1 and Kv2.2) and several "silent" alpha subunits (Kv2.3, Kv5, Kv6, Kv8, and Kv9), which do not generate K current. However, e.g., Kv8.1, via heteromerization, inhibits outward currents of the same family or even that of Shaw. This property of Kv8.1 is similar to those of designated beta subunits or non-selective auxiliary elements, including ADAM or AMIGO proteins. Kv channels and, in turn, ADAM may modulate the synaptic long-term potentiation (LTP). Prevailingly, Kv1.1 and Kv1.5 are attributed to respective brain and heart pathologies, some of which may occur simultaneously. The aforementioned channel proteins are apparently involved in several brain pathologies, including schizophrenia and seizures.
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Affiliation(s)
- Sodikdjon A. Kodirov
- Department of Biological Sciences, University of Texas at Brownsville, Brownsville, TX 78520 USA
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint Petersburg, Russia
- Instituto de Medicina Molecular, Universidade de Lisboa, 1649-028 Lisbon, Portugal
- Almazov Federal Heart, Blood and Endocrinology Centre, Saint Petersburg, 197341 Russia
- Institute for Physiology and Pathophysiology, Johannes Kepler University, Linz, Austria
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Zhang LM, Chen L, Zhao YF, Duan WM, Zhong LM, Liu MW. Identification of key potassium channel genes of temporal lobe epilepsy by bioinformatics analyses and experimental verification. Front Neurol 2023; 14:1175007. [PMID: 37483435 PMCID: PMC10361730 DOI: 10.3389/fneur.2023.1175007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/16/2023] [Indexed: 07/25/2023] Open
Abstract
One of the most prevalent types of epilepsy is temporal lobe epilepsy (TLE), which has unknown etiological factors and drug resistance. The detailed mechanisms underlying potassium channels in human TLE have not yet been elucidated. Hence, this study aimed to mine potassium channel genes linked to TLE using a bioinformatic approach. The results found that Four key TLE-related potassium channel genes (TERKPCGs) were identified: potassium voltage-gated channel subfamily E member (KCNA) 1, KCNA2, potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11), and KCNS1. A protein-protein interaction (PPI) network was constructed to analyze the relationship between TERKPCGs and other key module genes. The results of gene set enrichment analysis (GSEA) for a single gene indicated that the four TERKPCGs were highly linked to the cation channel, potassium channel, respiratory chain, and oxidative phosphorylation. The mRNA-TF network was established using four mRNAs and 113 predicted transcription factors. A ceRNA network containing seven miRNAs, two mRNAs, and 244 lncRNAs was constructed based on the TERKPCGs. Three common small-molecule drugs (enflurane, promethazine, and miconazole) target KCNA1, KCNA2, and KCNS1. Ten small-molecule drugs (glimepiride, diazoxide, levosimendan, and thiamylal et al.) were retrieved for KCNJ11. Compared to normal mice, the expression of KCNA1, KCNA2, KCNJ11, and KCNS1 was downregulated in the brain tissue of the epilepsy mouse model at both the transcriptional and translational levels, which was consistent with the trend of human data from the public database. The results indicated that key potassium channel genes linked to TLE were identified based on bioinformatics analysis to investigate the potential significance of potassium channel genes in the development and treatment of TLE.
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Affiliation(s)
- Lin-ming Zhang
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Ling Chen
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Yi-fei Zhao
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Wei-mei Duan
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Lian-mei Zhong
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Ming-wei Liu
- Department of Emergency, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
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Hu A, Zhao R, Ren B, Li Y, Lu J, Tai Y. Projection-Specific Heterogeneity of the Axon Initial Segment of Pyramidal Neurons in the Prelimbic Cortex. Neurosci Bull 2023; 39:1050-1068. [PMID: 36849716 PMCID: PMC10313623 DOI: 10.1007/s12264-023-01038-5] [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: 06/08/2022] [Accepted: 11/22/2022] [Indexed: 03/01/2023] Open
Abstract
The axon initial segment (AIS) is a highly specialized axonal compartment where the action potential is initiated. The heterogeneity of AISs has been suggested to occur between interneurons and pyramidal neurons (PyNs), which likely contributes to their unique spiking properties. However, whether the various characteristics of AISs can be linked to specific PyN subtypes remains unknown. Here, we report that in the prelimbic cortex (PL) of the mouse, two types of PyNs with axon projections either to the contralateral PL or to the ipsilateral basal lateral amygdala, possess distinct AIS properties reflected by morphology, ion channel expression, action potential initiation, and axo-axonic synaptic inputs from chandelier cells. Furthermore, projection-specific AIS diversity is more prominent in the superficial layer than in the deep layer. Thus, our study reveals the cortical layer- and axon projection-specific heterogeneity of PyN AISs, which may endow the spiking of various PyN types with exquisite modulation.
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Affiliation(s)
- Ankang Hu
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China
- School of Clinical Medicine, Fudan University, Shanghai, 200032, China
| | - Rui Zhao
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Baihui Ren
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yang Li
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Jiangteng Lu
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
- Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai, 201210, China.
| | - Yilin Tai
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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Labbaf A, Dellin M, Komadowski M, Chetkovich DM, Decher N, Pape HC, Seebohm G, Budde T, Zobeiri M. Characterization of Kv1.2-mediated outward current in TRIP8b-deficient mice. Biol Chem 2023; 404:291-302. [PMID: 36852869 DOI: 10.1515/hsz-2023-0116] [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: 01/30/2023] [Accepted: 02/16/2023] [Indexed: 03/01/2023]
Abstract
Tonic current through hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels is influencing neuronal firing properties and channel function is strongly influenced by the brain-specific auxiliary subunit tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b). Since Kv1.2 channels and TRIP8b were also suggested to interact, we assessed brain Kv1.2 mRNA and protein expression as well as the reduction of K+ outward currents by Kv1.2-blocking compounds (Psora-4; tityustoxin-Kα, TsTX-Kα) in different brain areas of TRIP8b-deficient (TRIP8b -/- ) compared to wildtype (WT) mice. We found that transcription levels of Kv1.2 channels were not different between genotypes. Furthermore, Kv1.2 current amplitude was not affected upon co-expression with TRIP8b in oocytes. However, Kv1.2 immunofluorescence was stronger in dendritic areas of cortical and hippocampal neurons. Furthermore, the peak net outward current was increased and the inactivation of the Psora-4-sensitive current component was less pronounced in cortical neurons in TRIP8b -/- mice. In current clamp recordings, application of TsTX increased the excitability of thalamocortical (TC) neurons with increased number of elicited action potentials upon step depolarization. We conclude that TRIP8b may not preferentially influence the amplitude of current through Kv1.2 channels but seems to affect current inactivation and channel localization. In TRIP8b -/- a compensatory upregulation of other Kv channels was observed.
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Affiliation(s)
- Afsaneh Labbaf
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149 Münster, Germany
| | - Maurice Dellin
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Robert-Koch-Str. 45, D-48149 Münster, Germany
| | - Marlene Komadowski
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
| | - Dane M Chetkovich
- Medical Center, Department of Neurology, Vanderbilt University, Nashville, TN, USA
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
| | - Hans-Chrisitian Pape
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149 Münster, Germany
| | - Guiscard Seebohm
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Robert-Koch-Str. 45, D-48149 Münster, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149 Münster, Germany
| | - Mehrnoush Zobeiri
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149 Münster, Germany
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Primak AL, Orlov NA, Peigneur S, Tytgat J, Ignatova AA, Denisova KR, Yakimov SA, Kirpichnikov MP, Nekrasova OV, Feofanov AV. AgTx2-GFP, Fluorescent Blocker Targeting Pharmacologically Important K v1.x (x = 1, 3, 6) Channels. Toxins (Basel) 2023; 15:toxins15030229. [PMID: 36977120 PMCID: PMC10056440 DOI: 10.3390/toxins15030229] [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: 02/14/2023] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
The growing interest in potassium channels as pharmacological targets has stimulated the development of their fluorescent ligands (including genetically encoded peptide toxins fused with fluorescent proteins) for analytical and imaging applications. We report on the properties of agitoxin 2 C-terminally fused with enhanced GFP (AgTx2-GFP) as one of the most active genetically encoded fluorescent ligands of potassium voltage-gated Kv1.x (x = 1, 3, 6) channels. AgTx2-GFP possesses subnanomolar affinities for hybrid KcsA-Kv1.x (x = 3, 6) channels and a low nanomolar affinity to KcsA-Kv1.1 with moderate dependence on pH in the 7.0-8.0 range. Electrophysiological studies on oocytes showed a pore-blocking activity of AgTx2-GFP at low nanomolar concentrations for Kv1.x (x = 1, 3, 6) channels and at micromolar concentrations for Kv1.2. AgTx2-GFP bound to Kv1.3 at the membranes of mammalian cells with a dissociation constant of 3.4 ± 0.8 nM, providing fluorescent imaging of the channel membranous distribution, and this binding depended weakly on the channel state (open or closed). AgTx2-GFP can be used in combination with hybrid KcsA-Kv1.x (x = 1, 3, 6) channels on the membranes of E. coli spheroplasts or with Kv1.3 channels on the membranes of mammalian cells for the search and study of nonlabeled peptide pore blockers, including measurement of their affinity.
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Affiliation(s)
- Alexandra L Primak
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Nikita A Orlov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Steve Peigneur
- Toxicology and Pharmacology, Campus Gasthuisberg O&N2, University of Leuven (KU Leuven), Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Jan Tytgat
- Toxicology and Pharmacology, Campus Gasthuisberg O&N2, University of Leuven (KU Leuven), Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Anastasia A Ignatova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Kristina R Denisova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Sergey A Yakimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Mikhail P Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Oksana V Nekrasova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Alexey V Feofanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
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10
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Sun S, Wang H. Clocking Epilepsies: A Chronomodulated Strategy-Based Therapy for Rhythmic Seizures. Int J Mol Sci 2023; 24:ijms24044223. [PMID: 36835631 PMCID: PMC9962262 DOI: 10.3390/ijms24044223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/08/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
Epilepsy is a neurological disorder characterized by hypersynchronous recurrent neuronal activities and seizures, as well as loss of muscular control and sometimes awareness. Clinically, seizures have been reported to display daily variations. Conversely, circadian misalignment and circadian clock gene variants contribute to epileptic pathogenesis. Elucidation of the genetic bases of epilepsy is of great importance because the genetic variability of the patients affects the efficacies of antiepileptic drugs (AEDs). For this narrative review, we compiled 661 epilepsy-related genes from the PHGKB and OMIM databases and classified them into 3 groups: driver genes, passenger genes, and undetermined genes. We discuss the potential roles of some epilepsy driver genes based on GO and KEGG analyses, the circadian rhythmicity of human and animal epilepsies, and the mutual effects between epilepsy and sleep. We review the advantages and challenges of rodents and zebrafish as animal models for epileptic studies. Finally, we posit chronomodulated strategy-based chronotherapy for rhythmic epilepsies, integrating several lines of investigation for unraveling circadian mechanisms underpinning epileptogenesis, chronopharmacokinetic and chronopharmacodynamic examinations of AEDs, as well as mathematical/computational modeling to help develop time-of-day-specific AED dosing schedules for rhythmic epilepsy patients.
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Affiliation(s)
- Sha Sun
- Center for Circadian Clocks, Soochow University, Suzhou 215123, China
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou 215123, China
| | - Han Wang
- Center for Circadian Clocks, Soochow University, Suzhou 215123, China
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou 215123, China
- Correspondence: or ; Tel.: +86-186-0512-8971
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11
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Zhou K, Luo W, Liu T, Ni Y, Qin Z. Neurotoxins Acting at Synaptic Sites: A Brief Review on Mechanisms and Clinical Applications. Toxins (Basel) 2022; 15:18. [PMID: 36668838 PMCID: PMC9865788 DOI: 10.3390/toxins15010018] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 12/29/2022] Open
Abstract
Neurotoxins generally inhibit or promote the release of neurotransmitters or bind to receptors that are located in the pre- or post-synaptic membranes, thereby affecting physiological functions of synapses and affecting biological processes. With more and more research on the toxins of various origins, many neurotoxins are now widely used in clinical treatment and have demonstrated good therapeutic outcomes. This review summarizes the structural properties and potential pharmacological effects of neurotoxins acting on different components of the synapse, as well as their important clinical applications, thus could be a useful reference for researchers and clinicians in the study of neurotoxins.
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Affiliation(s)
- Kunming Zhou
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, College of Pharmaceutical Sciences, Suzhou Medical College of Soochow University, Suzhou 215123, China
| | - Weifeng Luo
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou 215004, China
| | - Tong Liu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Yong Ni
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou 215004, China
| | - Zhenghong Qin
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, College of Pharmaceutical Sciences, Suzhou Medical College of Soochow University, Suzhou 215123, China
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12
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Gao K, Lin Z, Wen S, Jiang Y. Potassium channels and epilepsy. Acta Neurol Scand 2022; 146:699-707. [PMID: 36225112 DOI: 10.1111/ane.13695] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 08/16/2022] [Indexed: 01/10/2023]
Abstract
With the development and application of next-generation sequencing technology, the aetiological diagnosis of genetic epilepsy is rapidly becoming easier and less expensive. Additionally, there is a growing body of research into precision therapy based on genetic diagnosis. The numerous genes in the potassium ion channel family constitute the largest family of ion channels: this family is divided into different subtypes. Potassium ion channels play a crucial role in the electrical activity of neurons and are directly involved in the mechanism of epileptic seizures. In China, scientific research on genetic diagnosis and studies of precision therapy for genetic epilepsy are progressing rapidly. Many cases of epilepsy caused by mutation of potassium channel genes have been identified, and several potassium channel gene targets and drug candidates have been discovered. The purpose of this review is to briefly summarize the progress of research on the precise diagnosis and treatment of potassium ion channel-related genetic epilepsy, especially the research conducted in China. Here in, we review several large cohort studies on the genetic diagnosis of epilepsy in China in recent years, summarized the proportion of potassium channel genes. We focus on the progress of precison therapy on some hot epilepsy related potassium channel genes: KCNA1, KCNA2, KCNB1, KCNC1, KCND2, KCNQ2, KCNQ3, KCNMA1, and KCNT1.
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Affiliation(s)
- Kai Gao
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China.,Children Epilepsy Center, Peking University First Hospital, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
| | - Zehong Lin
- Department of Neurology, Affiliated Children's Hospital of Capital Institute of Pediatrics, Beijing, China
| | - Sijia Wen
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China.,Children Epilepsy Center, Peking University First Hospital, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China.,Children Epilepsy Center, Peking University First Hospital, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China.,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
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13
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Sun H, Patil MJ, Ru F, Meeker S, Undem BJ. K
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1/D‐type potassium channels inhibit the excitability of bronchopulmonary vagal afferent nerves. J Physiol 2022; 600:2953-2971. [PMID: 35430729 PMCID: PMC9203938 DOI: 10.1113/jp282803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/04/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract The KV1/D‐type potassium current (ID) is an important determinant of neuronal excitability. This study explored whether and how ID channels regulate the activation of bronchopulmonary vagal afferent nerves. The single‐neuron RT‐PCR assay revealed that nearly all mouse bronchopulmonary nodose neurons expressed the transcripts of α‐dendrotoxin (α‐DTX)‐sensitive, ID channel‐forming KV1.1, KV1.2 and/or KV1.6 α‐subunits, with the expression of KV1.6 being most prevalent. Patch‐clamp recordings showed that ID, defined as the α‐DTX‐sensitive K+ current, activated at voltages slightly more negative than the resting membrane potential in lung‐specific nodose neurons and displayed little inactivation at subthreshold voltages. Inhibition of ID channels by α‐DTX depolarized the lung‐specific nodose neurons and caused an increase in input resistance, decrease in rheobase, as well as increase in action potential number and firing frequency in response to suprathreshold current steps. Application of α‐DTX to the lungs via trachea in the mouse ex vivo vagally innervated trachea–lungs preparation led to action potential discharges in nearly half of bronchopulmonary nodose afferent nerve fibres, including nodose C‐fibres, as detected by the two‐photon microscopic Ca2+ imaging technique and extracellular electrophysiological recordings. In conclusion, ID channels act as a critical brake on the activation of bronchopulmonary vagal afferent nerves by stabilizing the membrane potential, counterbalancing the subthreshold depolarization and promoting the adaptation of action potential firings. Down‐regulation of ID channels, as occurs in various inflammatory diseases, may contribute to the enhanced C‐fibre activity in airway diseases that are associated with excessive coughing, dyspnoea, and reflex bronchospasm and secretions. Key points The α‐dendrotoxin (α‐DTX)‐sensitive D‐type K+ current (ID) is an important determinant of neuronal excitability. Nearly all bronchopulmonary nodose afferent neurons in the mouse express ID and the transcripts of α‐DTX‐sensitive, ID channel‐forming KV1.1, KV1.2 and/or KV1.6 α‐subunits. Inhibition of ID channels by α‐DTX depolarizes the bronchopulmonary nodose neurons, reduces the minimal depolarizing current needed to evoke an action potential (AP) and increases AP number and AP firing frequency in response to suprathreshold stimulations. Application of α‐DTX to the lungs ex vivo elicits AP discharges in about half of bronchopulmonary nodose C‐fibre terminals.
Our novel finding that ID channels act as a critical brake on the activation of bronchopulmonary vagal afferent nerves suggests that their down‐regulation, as occurs in various inflammatory diseases, may contribute to the enhanced C‐fibre activity in airway inflammation associated with excessive respiratory symptoms.
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Affiliation(s)
- Hui Sun
- Division of Allergy and Clinical Immunology Department of Medicine Johns Hopkins University School of Medicine 5501 Hopkins Bayview Circle Baltimore 21224
| | - Mayur J. Patil
- Division of Allergy and Clinical Immunology Department of Medicine Johns Hopkins University School of Medicine 5501 Hopkins Bayview Circle Baltimore 21224
| | - Fei Ru
- Division of Allergy and Clinical Immunology Department of Medicine Johns Hopkins University School of Medicine 5501 Hopkins Bayview Circle Baltimore 21224
| | - Sonya Meeker
- Division of Allergy and Clinical Immunology Department of Medicine Johns Hopkins University School of Medicine 5501 Hopkins Bayview Circle Baltimore 21224
| | - Bradley J. Undem
- Division of Allergy and Clinical Immunology Department of Medicine Johns Hopkins University School of Medicine 5501 Hopkins Bayview Circle Baltimore 21224
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14
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Wang H, Zhu Y, Cao D, Chen H, Ding X, Zeng Q, Zou H, Liao J. Successful medical treatment of west syndrome with a KCNA2 variant: a case report. ACTA EPILEPTOLOGICA 2022. [DOI: 10.1186/s42494-021-00069-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
West syndrome is a devastating disorder characterized by a triad of epileptic spasms, abnormal electroencephalography (EEG), and developmental arrest or psychomotor delay. In addition to early diagnosis, knowing the etiology of the condition is also important for its treatment. Among various etiologies, the genetic factors, especially mutations of ion channel genes, are very common and strongly linked to West syndrome.
Case presentation
A boy who had epileptic spasms from the age of 4 months was diagnosed with West syndrome based on the clinical manifestation and EEG results in Shenzhen Children’s Hospital in June 2019. Trios whole-exome sequencing (WES) test and protein structural model prediction were performed. We also reviewed the clinical and genetic features of this syndrome and the mechanisms of action of topiramate (TPM) by literature search in databases of Online Mendelian Inheritance in Man, Clinical Genome Resource, PubMed, Chinese National Knowledge Infrastructure and Wanfang database using keywords “KCNA2” “West syndrome” and “Topiramate” by December 2020. The relationship between the effect of TPM and the pathogenesis of the KCNA2 variant was also assessed. The WES test revealed c.244C > T/p. Arg82Cys varaint of KCNA2 (NM_004974.3) in this patient, and Sanger sequencing identified this was a de novo mutation. As far as we know, this is the first report of the c.244C > T/p. Arg82Cys variant in KCNA2, which was likely a pathogenic mutation. The seizures were successfully controlled for 10 months by TPM after failure of sodium valproate, large doses of vitamin B6, and adrenocorticotropic hormone. We speculate that the therapeutic effect of TPM in this patient is partially due to the inhibition of carbonic anhydrase.
Conclusions
Mutations in the KCNA2 gene should be considered for patients with West syndrome. The TPM treatment is probably effective for KCNA2-associated disorders.
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15
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CRISPR-Cas9-Mediated Gene Therapy in Neurological Disorders. Mol Neurobiol 2021; 59:968-982. [PMID: 34813019 DOI: 10.1007/s12035-021-02638-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/03/2021] [Indexed: 12/20/2022]
Abstract
Neurological disorders are primarily diseases with sophisticated etiology that are always refractory and recrudescent. The major obstruction to effective therapies for neurological disorders is the poor understanding of their pathogenic mechanisms. CRISPR-Cas9 technology, which allows precise and effective gene editing in almost any cell type and organism, is accelerating the pace of basic biological research. An increasing number of groups are focusing on uncovering the molecular mechanisms of neurological disorders and developing novel therapies using the CRISPR-Cas9 system. This review highlights the application of CRISPR-Cas9 technology in the treatment of neurological disorders, including Alzheimer's disease, amyotrophic lateral sclerosis and/or frontotemporal dementia, Duchenne muscular dystrophy, Dravet syndrome, epilepsy, Huntington's disease, and Parkinson's disease. Hopefully, it will improve our understanding of neurological disorders and give insights into future treatments for neurological disorders.
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16
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Studying Independent Kcna6 Knock-out Mice Reveals Toxicity of Exogenous LacZ to Central Nociceptor Terminals and Differential Effects of Kv1.6 on Acute and Neuropathic Pain Sensation. J Neurosci 2021; 41:9141-9162. [PMID: 34544832 DOI: 10.1523/jneurosci.0187-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 11/21/2022] Open
Abstract
The potassium channel Kv1.6 has recently been implicated as a major modulatory channel subunit expressed in primary nociceptors. Furthermore, its expression at juxtaparanodes of myelinated primary afferents is induced following traumatic nerve injury as part of an endogenous mechanism to reduce hyperexcitability and pain-related hypersensitivity. In this study, we compared two mouse models of constitutive Kv1.6 knock-out (KO) achieved by different methods: traditional gene trap via homologous recombination and CRISPR-mediated excision. Both Kv1.6 KO mouse lines exhibited an unexpected reduction in sensitivity to noxious heat stimuli, to differing extents: the Kv1.6 mice produced via gene trap had a far more significant hyposensitivity. These mice (Kcna6lacZ ) expressed the bacterial reporter enzyme LacZ in place of Kv1.6 as a result of the gene trap mechanism, and we found that their central primary afferent presynaptic terminals developed a striking neurodegenerative phenotype involving accumulation of lipid species, development of "meganeurites," and impaired transmission to dorsal horn wide dynamic range neurons. The anatomic defects were absent in CRISPR-mediated Kv1.6 KO mice (Kcna6 -/-) but were present in a third mouse model expressing exogenous LacZ in nociceptors under the control of a Nav1.8-promoted Cre recombinase. LacZ reporter enzymes are thus intrinsically neurotoxic to sensory neurons and may induce pathologic defects in transgenic mice, which has confounding implications for the interpretation of gene KOs using lacZ Nonetheless, in Kcna6 -/- mice not affected by LacZ, we demonstrated a significant role for Kv1.6 regulating acute noxious thermal sensitivity, and both mechanical and thermal pain-related hypersensitivity after nerve injury.SIGNIFICANCE STATEMENT In recent decades, the expansion of technologies to experimentally manipulate the rodent genome has contributed significantly to the field of neuroscience. While introduction of enzymatic or fluorescent reporter proteins to label neuronal populations is now commonplace, often potential toxicity effects are not fully considered. We show a role of Kv1.6 in acute and neuropathic pain states through analysis of two mouse models lacking Kv1.6 potassium channels: one with additional expression of LacZ and one without. We show that LacZ reporter enzymes induce unintended defects in sensory neurons, with an impact on behavioral data outcomes. To summarize we highlight the importance of Kv1.6 in recovery of normal sensory function following nerve injury, and careful interpretation of data from LacZ reporter models.
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17
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A Novel KCNA2 Variant in a Patient with Non-Progressive Congenital Ataxia and Epilepsy: Functional Characterization and Sensitivity to 4-Aminopyridine. Int J Mol Sci 2021; 22:ijms22189913. [PMID: 34576077 PMCID: PMC8469797 DOI: 10.3390/ijms22189913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/02/2021] [Accepted: 09/08/2021] [Indexed: 12/26/2022] Open
Abstract
Kv1.2 channels, encoded by the KCNA2 gene, are localized in the central and peripheral nervous system, where they regulate neuronal excitability. Recently, heterozygous mutations in KCNA2 have been associated with a spectrum of symptoms extending from epileptic encephalopathy, intellectual disability, and cerebellar ataxia. Patients are treated with a combination of antiepileptic drugs and 4-aminopyridine (4-AP) has been recently trialed in specific cases. We identified a novel variant in KCNA2, E236K, in a Serbian proband with non-progressive congenital ataxia and early onset epilepsy, treated with sodium valproate. To ascertain the pathogenicity of E236K mutation and to verify its sensitivity to 4-AP, we transfected HEK 293 cells with Kv1.2 WT or E236K cDNAs and recorded potassium currents through the whole-cell patch-clamp. In silico analysis supported the electrophysiological data. E236K channels showed voltage-dependent activation shifted towards negative potentials and slower kinetics of deactivation and activation compared with Kv1.2 WT. Heteromeric Kv1.2 WT+E236K channels, resembling the condition of the heterozygous patient, confirmed a mixed gain- and loss-of-function (GoF/LoF) biophysical phenotype. 4-AP inhibited both Kv1.2 and E236K channels with similar potency. Homology modeling studies of mutant channels suggested a reduced interaction between the residue K236 in the S2 segment and the gating charges at S4. Overall, the biophysical phenotype of E236K channels correlates with the mild end of the clinical spectrum reported in patients with GoF/LoF defects. The response to 4-AP corroborates existing evidence that KCNA2-disorders could benefit from variant-tailored therapeutic approaches, based on functional studies.
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18
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Chou SM, Li KX, Huang MY, Chen C, Lin King YH, Li GG, Zhou W, Teo CF, Jan YN, Jan LY, Yang SB. Kv1.1 channels regulate early postnatal neurogenesis in mouse hippocampus via the TrkB signaling pathway. eLife 2021; 10:e58779. [PMID: 34018923 PMCID: PMC8208815 DOI: 10.7554/elife.58779] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 05/20/2021] [Indexed: 12/20/2022] Open
Abstract
In the postnatal brain, neurogenesis occurs only within a few regions, such as the hippocampal sub-granular zone (SGZ). Postnatal neurogenesis is tightly regulated by factors that balance stem cell renewal with differentiation, and it gives rise to neurons that participate in learning and memory formation. The Kv1.1 channel, a voltage-gated potassium channel, was previously shown to suppress postnatal neurogenesis in the SGZ in a cell-autonomous manner. In this study, we have clarified the physiological and molecular mechanisms underlying Kv1.1-dependent postnatal neurogenesis. First, we discovered that the membrane potential of neural progenitor cells is highly dynamic during development. We further established a multinomial logistic regression model for cell-type classification based on the biophysical characteristics and corresponding cell markers. We found that the loss of Kv1.1 channel activity causes significant depolarization of type 2b neural progenitor cells. This depolarization is associated with increased tropomyosin receptor kinase B (TrkB) signaling and proliferation of neural progenitor cells; suppressing TrkB signaling reduces the extent of postnatal neurogenesis. Thus, our study defines the role of the Kv1.1 potassium channel in regulating the proliferation of postnatal neural progenitor cells in mouse hippocampus.
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Affiliation(s)
- Shu-Min Chou
- Institute of Biomedical Sciences, Academia SinicaTaipeiTaiwan
| | - Ke-Xin Li
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | | | - Chao Chen
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Yuan-Hung Lin King
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Neuroscience Graduate Program, University of California, San FranciscoSan FranciscoUnited States
| | | | - Wei Zhou
- Department of Anesthesia and Perioperative Care, University of California, San FranciscoSan FranciscoUnited States
| | - Chin Fen Teo
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Yuh Nung Jan
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Lily Yeh Jan
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Shi-Bing Yang
- Institute of Biomedical Sciences, Academia SinicaTaipeiTaiwan
- Neuroscience Program of Academia Sinica, Academia SinicaTaipeiTaiwan
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19
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Nikitin ES, Vinogradova LV. Potassium channels as prominent targets and tools for the treatment of epilepsy. Expert Opin Ther Targets 2021; 25:223-235. [PMID: 33754930 DOI: 10.1080/14728222.2021.1908263] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION K+ channels are of great interest to epilepsy research as mutations in their genes are found in humans with inherited epilepsy. At the level of cellular physiology, K+ channels control neuronal intrinsic excitability and are the main contributors to membrane repolarization of active neurons. Recently, a genetically modified voltage-dependent K+ channel has been patented as a remedy for epileptic seizures. AREAS COVERED We review the role of potassium channels in excitability, clinical and experimental evidence for the association of potassium channelopathies with epilepsy, the targeting of K+ channels by drugs, and perspectives of gene therapy in epilepsy with the expression of extra K+ channels in the brain. EXPERT OPINION Control over K+ conductance is of great potential benefit for the treatment of epilepsy. Nowadays, gene therapy affecting K+ channels is one of the most promising approaches to treat pharmacoresistant focal epilepsy.
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Affiliation(s)
- E S Nikitin
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - L V Vinogradova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
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20
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In Search of Molecular Markers for Cerebellar Neurons. Int J Mol Sci 2021; 22:ijms22041850. [PMID: 33673348 PMCID: PMC7918299 DOI: 10.3390/ijms22041850] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/09/2021] [Accepted: 02/09/2021] [Indexed: 02/06/2023] Open
Abstract
The cerebellum, the region of the brain primarily responsible for motor coordination and balance, also contributes to non-motor functions, such as cognition, speech, and language comprehension. Maldevelopment and dysfunction of the cerebellum lead to cerebellar ataxia and may even be associated with autism, depression, and cognitive deficits. Hence, normal development of the cerebellum and its neuronal circuitry is critical for the cerebellum to function properly. Although nine major types of cerebellar neurons have been identified in the cerebellar cortex to date, the exact functions of each type are not fully understood due to a lack of cell-specific markers in neurons that renders cell-specific labeling and functional study by genetic manipulation unfeasible. The availability of cell-specific markers is thus vital for understanding the role of each neuronal type in the cerebellum and for elucidating the interactions between cell types within both the developing and mature cerebellum. This review discusses various technical approaches and recent progress in the search for cell-specific markers for cerebellar neurons.
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21
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Wu J, Kaczmarek LK. Modulation of Neuronal Potassium Channels During Auditory Processing. Front Neurosci 2021; 15:596478. [PMID: 33613177 PMCID: PMC7887315 DOI: 10.3389/fnins.2021.596478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/11/2021] [Indexed: 11/16/2022] Open
Abstract
The extraction and localization of an auditory stimulus of interest from among multiple other sounds, as in the ‘cocktail-party’ situation, requires neurons in auditory brainstem nuclei to encode the timing, frequency, and intensity of sounds with high fidelity, and to compare inputs coming from the two cochleae. Accurate localization of sounds requires certain neurons to fire at high rates with high temporal accuracy, a process that depends heavily on their intrinsic electrical properties. Studies have shown that the membrane properties of auditory brainstem neurons, particularly their potassium currents, are not fixed but are modulated in response to changes in the auditory environment. Here, we review work focusing on how such modulation of potassium channels is critical to shaping the firing pattern and accuracy of these neurons. We describe how insights into the role of specific channels have come from human gene mutations that impair localization of sounds in space. We also review how short-term and long-term modulation of these channels maximizes the extraction of auditory information, and how errors in the regulation of these channels contribute to deficits in decoding complex auditory information.
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Affiliation(s)
- Jing Wu
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, United States
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, United States
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22
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Khoubza L, Chatelain FC, Feliciangeli S, Lesage F, Bichet D. Physiological roles of heteromerization: focus on the two-pore domain potassium channels. J Physiol 2021; 599:1041-1055. [PMID: 33347640 DOI: 10.1113/jp279870] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 12/07/2020] [Indexed: 12/28/2022] Open
Abstract
Potassium channels form the largest family of ion channels with more than 80 members involved in cell excitability and signalling. Most of them exist as homomeric channels, whereas specific conditions are required to obtain heteromeric channels. It is well established that heteromerization of voltage-gated and inward rectifier potassium channels affects their function, increasing the diversity of the native potassium currents. For potassium channels with two pore domains (K2P ), homomerization has long been considered the rule, their polymodal regulation by a wide diversity of physical and chemical stimuli being responsible for the adaptation of the leak potassium currents to cellular needs. This view has recently evolved with the accumulation of evidence of heteromerization between different K2P subunits. Several functional intragroup and intergroup heteromers have recently been identified, which contribute to the functional heterogeneity of this family. K2P heteromerization is involved in the modulation of channel expression and trafficking, promoting functional and signalling diversity. As illustrated in the Abstract Figure, heteromerization of TREK1 and TRAAK provides the cell with more possibilities of regulation. It is becoming increasingly evident that K2P heteromers contribute to important physiological functions including neuronal and cardiac excitability. Since heteromerization also affects the pharmacology of K2P channels, this understanding helps to establish K2P heteromers as new therapeutic targets for physiopathological conditions.
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Affiliation(s)
- Lamyaa Khoubza
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France
| | - Franck C Chatelain
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France
| | - Sylvain Feliciangeli
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France.,Inserm, 101 rue de Tolbiac, 75013, Paris, France
| | - Florian Lesage
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France.,Inserm, 101 rue de Tolbiac, 75013, Paris, France
| | - Delphine Bichet
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France
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Lugarà E, Kaushik R, Leite M, Chabrol E, Dityatev A, Lignani G, Walker MC. LGI1 downregulation increases neuronal circuit excitability. Epilepsia 2020; 61:2836-2846. [DOI: 10.1111/epi.16736] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/29/2020] [Accepted: 09/29/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Eleonora Lugarà
- Department of Clinical and Experimental Epilepsy UCL Queen Square Institute of Neurology London UK
| | - Rahul Kaushik
- German Center for Neurodegenerative Diseases Magdeburg Germany
- Center for Behavioral Brain Sciences Magdeburg Germany
| | - Marco Leite
- Department of Clinical and Experimental Epilepsy UCL Queen Square Institute of Neurology London UK
| | - Elodie Chabrol
- Department of Clinical and Experimental Epilepsy UCL Queen Square Institute of Neurology London UK
| | - Alexander Dityatev
- German Center for Neurodegenerative Diseases Magdeburg Germany
- Center for Behavioral Brain Sciences Magdeburg Germany
- Medical Faculty Otto von Guericke University Magdeburg Germany
| | - Gabriele Lignani
- Department of Clinical and Experimental Epilepsy UCL Queen Square Institute of Neurology London UK
| | - Matthew C. Walker
- Department of Clinical and Experimental Epilepsy UCL Queen Square Institute of Neurology London UK
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24
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Johnson A, Grove RA, Madhavan D, Boone CHT, Braga C, Kyllo H, Samson K, Simeone K, Simeone T, Helikar T, Hanson CK, Adamec J. Changes in lipid profiles of epileptic mouse model. Metabolomics 2020; 16:106. [PMID: 33021695 PMCID: PMC10614666 DOI: 10.1007/s11306-020-01729-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 09/23/2020] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Approximately 1% of the world's population is impacted by epilepsy, a chronic neurological disorder characterized by seizures. One-third of epileptic patients are resistant to AEDs, or have medically refractory epilepsy (MRE). One non-invasive treatment that exists for MRE includes the ketogenic diet, a high-fat, low-carbohydrate diet. Despite the KD's success in seizure attenuation, it has a few risks and its mechanisms remain poorly understood. The KD has been shown to improve metabolism and mitochondrial function in epileptic phenotypes. Potassium channels have implications in epileptic conditions as they have dual roles as metabolic sensors and control neuronal excitation. OBJECTIVES The goal of this study was to explore changes in the lipidome in hippocampal and cortical tissue from Kv1.1-KO model of epilepsy. METHODS FT-ICR/MS analysis was utilized to examine nonpolar metabolome of cortical and hippocampal tissue isolated from a Kv1.1 channel knockout mouse model of epilepsy (n = 5) and wild-type mice (n = 5). RESULTS Distinct metabolic profiles were observed, significant (p < 0.05) features in hippocampus often being upregulated (FC ≥ 2) and the cortex being downregulated (FC ≤ 0.5). Pathway enrichment analysis shows lipid biosynthesis was affected. Partition ratio analysis revealed that the ratio of most metabolites tended to be increased in Kv1.1-/-. Metabolites in hippocampal tissue were commonly upregulated, suggesting seizure initiation in the hippocampus. Aberrant mitochondrial function is implicated by the upregulation of cardiolipin, a common component in the mitochondrial membrane. CONCLUSION Generally, our study finds that the lipidome is changed in the hippocampus and cortex in response to Kv1.1-KO indicating changes in membrane structural integrity and synaptic transmission.
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Affiliation(s)
- Alicia Johnson
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Ryan A Grove
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Deepak Madhavan
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Cory H T Boone
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Camila Braga
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Hannah Kyllo
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Kaeli Samson
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Kristina Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Timothy Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Tomas Helikar
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Corrine K Hanson
- College of Allied Health Professions, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Jiri Adamec
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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Gavrilovici C, Jiang Y, Kiroski I, Teskey GC, Rho JM, Nguyen MD. Postnatal Role of the Cytoskeleton in Adult Epileptogenesis. Cereb Cortex Commun 2020; 1:tgaa024. [PMID: 32864616 PMCID: PMC7446231 DOI: 10.1093/texcom/tgaa024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/08/2020] [Accepted: 06/11/2020] [Indexed: 02/07/2023] Open
Abstract
Mutations in cytoskeletal proteins can cause early infantile and childhood epilepsies by misplacing newly born neurons and altering neuronal connectivity. In the adult epileptic brain, cytoskeletal disruption is often viewed as being secondary to aberrant neuronal activity and/or death, and hence simply represents an epiphenomenon. Here, we review the emerging evidence collected in animal models and human studies implicating the cytoskeleton as a potential causative factor in adult epileptogenesis. Based on the emerging evidence, we propose that cytoskeletal disruption may be an important pathogenic mechanism in the mature epileptic brain.
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Affiliation(s)
- Cezar Gavrilovici
- Departments of Neurosciences & Pediatrics, University of California San Diego, Rady Children's Hospital San Diego, San Diego, CA 92123, USA
| | - Yulan Jiang
- Departments of Clinical Neurosciences, Cell Biology & Anatomy, and Biochemistry & Molecular Biology, Hotchkiss Brain Institute, Alberta Children Hospital Research Institute, University of Calgary, Calgary T2N 4N1, Canada
| | - Ivana Kiroski
- Departments of Clinical Neurosciences, Cell Biology & Anatomy, and Biochemistry & Molecular Biology, Hotchkiss Brain Institute, Alberta Children Hospital Research Institute, University of Calgary, Calgary T2N 4N1, Canada
| | - G Campbell Teskey
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute, Alberta Children Hospital Research Institute, University of Calgary, Calgary T2N 4N1, Canada
| | - Jong M Rho
- Departments of Neurosciences & Pediatrics, University of California San Diego, Rady Children's Hospital San Diego, San Diego, CA 92123, USA
| | - Minh Dang Nguyen
- Departments of Clinical Neurosciences, Cell Biology & Anatomy, and Biochemistry & Molecular Biology, Hotchkiss Brain Institute, Alberta Children Hospital Research Institute, University of Calgary, Calgary T2N 4N1, Canada
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Clinical Spectrum of KCNA1 Mutations: New Insights into Episodic Ataxia and Epilepsy Comorbidity. Int J Mol Sci 2020; 21:ijms21082802. [PMID: 32316562 PMCID: PMC7215408 DOI: 10.3390/ijms21082802] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 12/13/2022] Open
Abstract
Mutations in the KCNA1 gene, which encodes voltage-gated Kv1.1 potassium channel α-subunits, cause a variety of human diseases, complicating simple genotype–phenotype correlations in patients. KCNA1 mutations are primarily associated with a rare neurological movement disorder known as episodic ataxia type 1 (EA1). However, some patients have EA1 in combination with epilepsy, whereas others have epilepsy alone. KCNA1 mutations can also cause hypomagnesemia and paroxysmal dyskinesia in rare cases. Why KCNA1 variants are associated with such phenotypic heterogeneity in patients is not yet understood. In this review, literature databases (PubMed) and public genetic archives (dbSNP and ClinVar) were mined for known pathogenic or likely pathogenic mutations in KCNA1 to examine whether patterns exist between mutation type and disease manifestation. Analyses of the 47 deleterious KCNA1 mutations that were identified revealed that epilepsy or seizure-related variants tend to cluster in the S1/S2 transmembrane domains and in the pore region of Kv1.1, whereas EA1-associated variants occur along the whole length of the protein. In addition, insights from animal models of KCNA1 channelopathy were considered, as well as the possible influence of genetic modifiers on disease expressivity and severity. Elucidation of the complex relationship between KCNA1 variants and disease will enable better diagnostic risk assessment and more personalized therapeutic strategies for KCNA1 channelopathy.
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Spaiardi P, Tavazzani E, Manca M, Russo G, Prigioni I, Biella G, Giunta R, Johnson SL, Marcotti W, Masetto S. K + Accumulation and Clearance in the Calyx Synaptic Cleft of Type I Mouse Vestibular Hair Cells. Neuroscience 2020; 426:69-86. [PMID: 31846752 PMCID: PMC6985899 DOI: 10.1016/j.neuroscience.2019.11.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 11/07/2019] [Accepted: 11/16/2019] [Indexed: 11/29/2022]
Abstract
Vestibular organs of Amniotes contain two types of sensory cells, named Type I and Type II hair cells. While Type II hair cells are contacted by several small bouton nerve terminals, Type I hair cells receive a giant terminal, called a calyx, which encloses their basolateral membrane almost completely. Both hair cell types release glutamate, which depolarizes the afferent terminal by binding to AMPA post-synaptic receptors. However, there is evidence that non-vesicular signal transmission also occurs at the Type I hair cell-calyx synapse, possibly involving direct depolarization of the calyx by K+ exiting the hair cell. To better investigate this aspect, we performed whole-cell patch-clamp recordings from mouse Type I hair cells or their associated calyx. We found that [K+] in the calyceal synaptic cleft is elevated at rest relative to the interstitial (extracellular) solution and can increase or decrease during hair cell depolarization or repolarization, respectively. The change in [K+] was primarily driven by GK,L, the low-voltage-activated, non-inactivating K+ conductance specifically expressed by Type I hair cells. Simple diffusion of K+ between the cleft and the extracellular compartment appeared substantially restricted by the calyx inner membrane, with the ion channels and active transporters playing a crucial role in regulating intercellular [K+]. Calyx recordings were consistent with K+ leaving the synaptic cleft through postsynaptic voltage-gated K+ channels involving KV1 and KV7 subunits. The above scenario is consistent with direct depolarization and hyperpolarization of the calyx membrane potential by intercellular K+.
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Affiliation(s)
- P Spaiardi
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - E Tavazzani
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - M Manca
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - G Russo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - I Prigioni
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - G Biella
- Department of Biology and Biotechnology, University of Pavia, Pavia 27100, Italy
| | - R Giunta
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - S L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - W Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - S Masetto
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy.
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Yang F, Yang L, Wataya-Kaneda M, Teng L, Katayama I. Epilepsy in a melanocyte-lineage mTOR hyperactivation mouse model: A novel epilepsy model. PLoS One 2020; 15:e0228204. [PMID: 31978189 PMCID: PMC6980560 DOI: 10.1371/journal.pone.0228204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/09/2020] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To clarify the complex mechanism underlying epileptogeneis, a novel animal model was generated. METHODS In our previous research, we have generated a melanocyte-lineage mTOR hyperactivation mouse model (Mitf-M-Cre Tsc2 KO mice; cKO mice) to investigate mTOR pathway in melanogenesis regulation, markedly reduced skin pigmentation was observed. Very unexpectedly, spontaneous recurrent epilepsy was also developed in this mouse model. RESULTS Compared with control littermates, no change was found in either brain size or brain mass in cKO mice. Hematoxylin staining revealed no obvious aberrant histologic features in the whole brains of cKO mice. Histoimmunofluorescence staining and electron microscopy examination revealed markedly increased mTOR signaling and hyperproliferation of mitochondria in cKO mice, especially in the hippocampus. Furthermore, rapamycin treatment reversed these abnormalities. CONCLUSIONS This study suggests that our melanocyte-lineage mTOR hyperactivation mouse is a novel animal model of epilepsy, which may promote the progress of both epilepsy and neurophysiology research.
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Affiliation(s)
- Fei Yang
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Lingli Yang
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Mari Wataya-Kaneda
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Lanting Teng
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Ichiro Katayama
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
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29
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Ison JR, Allen PD, Tempel BL, Brew HM. Sound Localization in Preweanling Mice Was More Severely Affected by Deleting the Kcna1 Gene Compared to Deleting Kcna2, and a Curious Inverted-U Course of Development That Appeared to Exceed Adult Performance Was Observed in All Groups. J Assoc Res Otolaryngol 2019; 20:565-577. [PMID: 31410614 PMCID: PMC6889093 DOI: 10.1007/s10162-019-00731-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 07/18/2019] [Indexed: 11/30/2022] Open
Abstract
The submillisecond acuity for detecting rapid spatial and temporal fluctuations in acoustic stimuli observed in humans and laboratory animals depends in part on select groups of auditory neurons that preserve synchrony from the ears to the binaural nuclei in the brainstem. These fibers have specialized synapses and axons that use a low-threshold voltage-activated outward current, IKL, conducted through Kv1 potassium ion channels. These are in turn coupled with HCN channels that express a mixed cation inward mixed current, IH, to support precise synchronized firing. The behavioral evidence is that their respective Kcna1 or HCN1 genes are absent in adult mice; the results are weak startle reflexes, slow responding to noise offsets, and poor sound localization. The present behavioral experiments were motivated by an in vitro study reporting increased IKL in an auditory nucleus in Kcna2-/- mice lacking the Kv1.2 subunit, suggesting that Kcna2-/- mice might perform better than Kcna2+/+ mice. Because Kcna2-/- mice have only a 17-18-day lifespan, we compared both preweanling Kcna2-/- vs. Kcna2+/+ mice and Kcna1-/- vs. Kcna1+/+ mice at P12-P17/18; then, the remaining mice were tested at P23/P25. Both null mutant strains had a stunted physique, but the Kcna1-/- mice had severe behavioral deficits while those in Kcna2-/- mice were relatively few and minor. The in vitro increase of IKL could have resulted from Kv1.1 subunits substituting for Kv1.2 units and the loss of the inhibitory "managerial" effect of Kv1.2 on Kv1.1. However, any increased neuronal synchronicity that accompanies increased IKL may not have been enough to affect behavior. All mice performed unusually well on the early spatial tests, but then, they fell towards adult levels. This unexpected effect may reflect a shift from summated independent monaural pathways to integrated binaural processing, as has been suggested for similar observations for human infants.
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Affiliation(s)
- James R Ison
- Department of Brain and Cognitive Sciences, Meliora Hall, University of Rochester, Rochester, NY, 14627, USA.
- Department of Neuroscience and The Del Monte Neuromedicine Institute, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Paul D Allen
- Department of Otolaryngology, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Bruce L Tempel
- The Virginia Merrill Bloedel Hearing Research Center and the Departments of Otolaryngology-Head and Neck Surgery and Pharmacology, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Helen M Brew
- The Virginia Merrill Bloedel Hearing Research Center and the Departments of Otolaryngology-Head and Neck Surgery and Pharmacology, University of Washington School of Medicine, Seattle, WA, 98195, USA
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30
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Roles of ErbB3-binding protein 1 (EBP1) in embryonic development and gene-silencing control. Proc Natl Acad Sci U S A 2019; 116:24852-24860. [PMID: 31748268 DOI: 10.1073/pnas.1916306116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
ErbB3-binding protein 1 (EBP1) is implicated in diverse cellular functions, including apoptosis, cell proliferation, and differentiation. Here, by generating genetic inactivation of Ebp1 mice, we identified the physiological roles of EBP1 in vivo. Loss of Ebp1 in mice caused aberrant organogenesis, including brain malformation, and death between E13.5 and 15.5 owing to severe hemorrhages, with massive apoptosis and cessation of cell proliferation. Specific ablation of Ebp1 in neurons caused structural abnormalities of brain with neuron loss in [Nestin-Cre; Ebp1 flox/flox ] mice. Notably, global methylation increased with high levels of the gene-silencing unit Suv39H1/DNMT1 in Ebp1-deficient mice. EBP1 repressed the transcription of Dnmt1 by binding to its promoter region and interrupted DNMT1-mediated methylation at its target gene, Survivin promoter region. Reinstatement of EBP1 into embryo brain relived gene repression and rescued neuron death. Our findings uncover an essential role for EBP1 in embryonic development and implicate its function in transcriptional regulation.
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31
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Muheim CM, Spinnler A, Sartorius T, Dürr R, Huber R, Kabagema C, Ruth P, Brown SA. Dynamic- and Frequency-Specific Regulation of Sleep Oscillations by Cortical Potassium Channels. Curr Biol 2019; 29:2983-2992.e3. [PMID: 31474531 DOI: 10.1016/j.cub.2019.07.056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 06/15/2019] [Accepted: 07/17/2019] [Indexed: 10/26/2022]
Abstract
Primary electroencephalographic (EEG) features of sleep arise in part from thalamocortical neural assemblies, and cortical potassium channels have long been thought to play a critical role. We have exploited the regionally dynamic nature of sleep EEG to develop a novel screening strategy and used it to conduct an adeno-associated virus (AAV)-mediated RNAi screen for cellular roles of 31 different voltage-gated potassium channels in modulating cortical EEG features across the circadian sleep-wake cycle. Surprisingly, a majority of channels modified only electroencephalographic frequency bands characteristic of sleep, sometimes diurnally or even in specific vigilance states. Confirming our screen for one channel, we show that depletion of the KCa1.1 (or "BK") channel reduces EEG power in slow-wave sleep by slowing neuronal repolarization. Strikingly, this reduction completely abolishes transcriptomic changes between sleep and wake. Thus, our data establish an unexpected connection between transcription and EEG power controlled by specific potassium channels. We postulate that additive dynamic roles of individual potassium channels could integrate different influences upon sleep and wake within single neurons.
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Affiliation(s)
- Christine M Muheim
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Andrea Spinnler
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Tina Sartorius
- Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen 72076, Germany
| | - Roland Dürr
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Reto Huber
- University Children's Hospital Zurich, University of Zürich, Steinwiesstrasse 75, Zürich 8032, Switzerland
| | - Clement Kabagema
- Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen 72076, Germany
| | - Peter Ruth
- Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen 72076, Germany
| | - Steven A Brown
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, Zürich 8057, Switzerland.
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Abraham MJ, Fleming KL, Raymond S, Wong AYC, Bergeron R. The sigma-1 receptor behaves as an atypical auxiliary subunit to modulate the functional characteristics of Kv1.2 channels expressed in HEK293 cells. Physiol Rep 2019; 7:e14147. [PMID: 31222975 PMCID: PMC6586770 DOI: 10.14814/phy2.14147] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/17/2019] [Accepted: 05/25/2019] [Indexed: 12/11/2022] Open
Abstract
Expression of Kv1.2 within Kv1.x potassium channel complexes is critical in maintaining appropriate neuronal excitability and determining the threshold for action potential firing. This is attributed to the interaction of Kv1.2 with a hitherto unidentified protein that confers bimodal channel activation gating, allowing neurons to adapt to repetitive trains of stimulation and protecting against hyperexcitability. One potential protein candidate is the sigma-1 receptor (Sig-1R), which regulates other members of the Kv1.x channel family; however, the biophysical nature of the interaction between Sig-1R and Kv1.2 has not been elucidated. We hypothesized that Sig-1R may regulate Kv1.2 and may further act as the unidentified modulator of Kv1.2 activation. In transiently transfected HEK293 cells, we found that ligand activation of the Sig-1R modulates Kv1.2 current amplitude. More importantly, Sig-1R interacts with Kv1.2 in baseline conditions to influence bimodal activation gating. These effects are abolished in the presence of the auxiliary subunit Kvβ2 and when the Sig-1R mutation underlying ALS16 (Sig-1R-E102Q), is expressed. These data suggest that Kvβ2 occludes the interaction of Sig-1R with Kv1.2, and that E102 may be a residue critical for Sig-1R modulation of Kv1.2. The results of this investigation describe an important new role for Sig-1R in the regulation of neuronal excitability and introduce a novel mechanism of pathophysiology in Sig-1R dysfunction.
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Affiliation(s)
- Madelyn J. Abraham
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
| | - Kayla L. Fleming
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
| | - Sophie Raymond
- NeuroscienceOttawa Hospital Research InstituteOttawaOntarioCanada
| | | | - Richard Bergeron
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- NeuroscienceOttawa Hospital Research InstituteOttawaOntarioCanada
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Farrell JS, Nguyen QA, Soltesz I. Resolving the Micro-Macro Disconnect to Address Core Features of Seizure Networks. Neuron 2019; 101:1016-1028. [PMID: 30897354 PMCID: PMC6430140 DOI: 10.1016/j.neuron.2019.01.043] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/14/2018] [Accepted: 01/18/2019] [Indexed: 02/07/2023]
Abstract
Current drug treatments for epilepsy attempt to broadly restrict excitability to mask a symptom, seizures, with little regard for the heterogeneous mechanisms that underlie disease manifestation across individuals. Here, we discuss the need for a more complete view of epilepsy, outlining how key features at the cellular and microcircuit level can significantly impact disease mechanisms that are not captured by the most common methodology to study epilepsy, electroencephalography (EEG). We highlight how major advances in neuroscience tool development now enable multi-scale investigation of fundamental questions to resolve the currently controversial understanding of seizure networks. These findings will provide essential insight into what has emerged as a disconnect between the different levels of investigation and identify new targets and treatment options.
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Affiliation(s)
- Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA, USA.
| | - Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA.
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34
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Neurobiology and therapeutic applications of neurotoxins targeting transmitter release. Pharmacol Ther 2019; 193:135-155. [DOI: 10.1016/j.pharmthera.2018.08.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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35
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Saporito MS, Gruner JA, DiCamillo A, Hinchliffe R, Barker-Haliski M, White HS. Intravenously Administered Ganaxolone Blocks Diazepam-Resistant Lithium-Pilocarpine–Induced Status Epilepticus in Rats: Comparison with Allopregnanolone. J Pharmacol Exp Ther 2018; 368:326-337. [DOI: 10.1124/jpet.118.252155] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 12/12/2018] [Indexed: 11/22/2022] Open
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36
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Altered Auditory Processing, Filtering, and Reactivity in the Cntnap2 Knock-Out Rat Model for Neurodevelopmental Disorders. J Neurosci 2018; 38:8588-8604. [PMID: 30126973 DOI: 10.1523/jneurosci.0759-18.2018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 08/13/2018] [Accepted: 08/14/2018] [Indexed: 12/21/2022] Open
Abstract
Sensory processing, and auditory processing in particular, is altered in individuals with neurodevelopmental disorders such as autism spectrum disorders (ASDs). The typical maturation of the auditory system is perturbed in these individuals during early development, which may underlie altered auditory reactivity that persists in later life. Of the many genes that regulate the auditory system development, loss-of-function mutations in the CNTNAP2 gene are strongly associated with language processing deficits and ASD. Therefore, using a novel Cntnap2 knock-out rat model, we tested the impact of Cntnap2 loss on auditory processing, filtering, and reactivity throughout development and young adulthood in male and female animals. Although hearing thresholds were not altered in Cntnap2 knock-out animals, we found a reduction in response amplitudes and a delay in response latency of the auditory brainstem response (ABR) in juvenile Cntnap2 knock-out rats compared with age-matched controls. Amplitudes and latency of the ABR largely normalized by adulthood, indicating a delayed maturation of auditory processing pathways in Cntnap2 knock-out rats. Despite the reduced ABR amplitudes, adolescent Cntnap2 knock-out animals displayed increased startle reactivity accompanied by disruptions in sensory filtering and sensorimotor gating across various conditions, most of which persisted in adulthood. All of these observations show striking parallels to disruptions reported in ASD. Our results also imply that developmental disruptions of sensory signal processing are associated with persistent changes in neural circuitries responsible for implicit auditory evoked behavior, emphasizing the need for interventions that target sensory processing disruptions early during development in ASD.SIGNIFICANCE STATEMENT This is the first study of brainstem auditory processing in a novel knock-out rat model with very high construct and face validity for autism spectrum disorders. Electrophysiological and behavioral measures of implicit auditory-evoked responses were systematically taken across developmental stages. Auditory processing, filtering, and reactivity disruptions show striking similarities to observations in autism. We also show for the first time that, whereas auditory brainstem responses normalize by adulthood, disruptions in brainstem-mediated auditory-evoked behavior persist. This indicates that early developmental perturbations in sensory processing can cause permanent maladaptive changes in circuitries responsible for auditory reactivity, underlining the importance for interventions early during development aiming at normalizing sensory processing.
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Zhu P, Li J, Zhang L, Liang Z, Tang B, Liao WP, Yi YH, Su T. Development-related aberrations in Kv1.1 α-subunit exert disruptive effects on bioelectrical activities of neurons in a mouse model of fragile X syndrome. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:140-151. [PMID: 29481897 DOI: 10.1016/j.pnpbp.2018.02.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 02/22/2018] [Accepted: 02/22/2018] [Indexed: 10/18/2022]
Abstract
Kv1.1, a Shaker homologue potassium channel, plays a critical role in homeostatic regulation of neuronal excitability. Aberrations in the functional properties of Kv1.1 have been implicated in several neurological disorders featured by neuronal hyperexcitability. Fragile X syndrome (FXS), the most common form of inherited mental retardation, is characterized by hyperexcitability in neural network and intrinsic membrane properties. The Kv1.1 channel provides an intriguing mechanistic candidate for FXS. We investigated the development-related expression pattern of the Kv1.1 α-subunit by using a Fmr1 knockout (KO) mouse model of FXS. Markedly decreased protein expression of Kv1.1 was found in neonatal and adult stages when compared to age-matched wild-type (WT) mice. Immunohistochemical investigations supported the delayed development-related increases in Kv1.1 expression, especially in CA3 pyramidal neurons. By applying a Kv1.1-specific blocker, dendrotoxin-κ (DTX-κ), we isolated the Kv1.1-mediated currents in the CA3 pyramidal neurons. The isolated DTX-κ-sensitive current of neurons from KO mice exhibited decreased amplitude, lower threshold of activation, and faster recovery from inactivation. The equivalent reduction in potassium current in the WT neurons following application of the appropriate amount of DTX-κ reproduced the enhanced firing abilities of KO neurons, suggesting the Kv1.1 channel as a critical contributor to the hyperexcitability of KO neurons. The role of Kv1.1 in controlling neuronal discharges was further supported by the parallel developmental trajectories of Kv1.1 expression, current amplitude, and discharge impacts, with a significant correlation between the amplitude of Kv1.1-mediated currents and Kv1.1-blocking-induced firing enhancement. These data suggest that the expression of the Kv1.1 α-subunit has a profound pathological relevance to hyperexcitability in FXS, as well as implications for normal development, maintenance, and control of neuronal activities.
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Affiliation(s)
- Pingping Zhu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China; Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, Guangzhou, China
| | - Jialing Li
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Liting Zhang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Zhanrong Liang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Bin Tang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Wei-Ping Liao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Yong-Hong Yi
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Tao Su
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China.
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Abstract
The molecular process of RNA editing allows changes in RNA transcripts that increase genomic diversity. These highly conserved RNA editing events are catalyzed by a group of enzymes known as adenosine deaminases acting on double-stranded RNA (ADARs). ADARs are necessary for normal development, they bind to over thousands of genes, impact millions of editing sites, and target critical components of the central nervous system (CNS) such as glutamate receptors, serotonin receptors, and potassium channels. Dysfunctional ADARs are known to cause alterations in CNS protein products and therefore play a role in chronic or acute neurodegenerative and psychiatric diseases as well as CNS cancer. Here, we review how RNA editing deficiency impacts CNS function and summarize its role during disease pathogenesis.
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Affiliation(s)
- Ileana Lorenzini
- Barrow Neurological Institute, Department of Neurobiology, Dignity Health, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Stephen Moore
- Barrow Neurological Institute, Department of Neurobiology, Dignity Health, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
- Interdisciplinary Graduate Program in Neuroscience, Arizona State University, Tempe, AZ, USA
| | - Rita Sattler
- Department of Neurobiology and Neurology, Dignityhealth St. Joseph's Hospital, Barrow Neurological Institute, Phoenix, AZ, USA.
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Iyer SH, Matthews SA, Simeone TA, Maganti R, Simeone KA. Accumulation of rest deficiency precedes sudden death of epileptic Kv1.1 knockout mice, a model of sudden unexpected death in epilepsy. Epilepsia 2017; 59:92-105. [PMID: 29193044 DOI: 10.1111/epi.13953] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2017] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Chronic sleep deficiency is associated with early mortality. In the epileptic population, there is a higher prevalence of sleep disorders, and individuals with severe refractory epilepsy are at greater risk of premature mortality than the general population. Sudden unexpected death in epilepsy affects 1:1000 cases of epilepsy each year. Ketogenic diet (KD) treatment is one of the few effective options for refractory seizures. Despite KD reducing seizures and increasing longevity in Kv1.1 knockout (KO) mice, they still succumb to sudden death. This study aims to determine whether (1) the rest profiles of KO and KD-treated KO (KOKD) mice resemble each other as a function of either age or proximity to death and (2) the timing of death correlates with acute or chronic changes in rest. METHODS Noninvasive actimetry was used to monitor rest throughout the lives of KO and wild-type (WT) littermates administered standard diet or KD. RESULTS As KO mice age, rest is reduced (P < .0001). Rest is significantly improved in KDKO mice (P < .0001), resembling WT values at several ages. When age is removed as a variable and data are realigned to the day of death, the rest profiles of KO and KOKD groups worsen to similar degrees as a function of proximity to death. The amount of rest acutely is not sensitive to the timing of death, whereas chronic rest deficiency profiles (10-15 days prior to death) of both groups were indistinguishable. Chronic accumulation of rest deficiency over the final 15 days was associated with 75% of deaths. SIGNIFICANCE Our data suggest that the accumulated rest deficiency is associated with sudden death in Kv1.1 KO mice. These data (1) support the proposed clinical hypothesis that chronic sleep deficiency may be associated with early mortality in epileptic patients and (2) warrant future preclinical and clinical studies on sleep monitoring in epileptic patients.
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Affiliation(s)
- Shruthi H Iyer
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Stephanie A Matthews
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Timothy A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Rama Maganti
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Kristina A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
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Masnada S, Hedrich UBS, Gardella E, Schubert J, Kaiwar C, Klee EW, Lanpher BC, Gavrilova RH, Synofzik M, Bast T, Gorman K, King MD, Allen NM, Conroy J, Ben Zeev B, Tzadok M, Korff C, Dubois F, Ramsey K, Narayanan V, Serratosa JM, Giraldez BG, Helbig I, Marsh E, O'Brien M, Bergqvist CA, Binelli A, Porter B, Zaeyen E, Horovitz DD, Wolff M, Marjanovic D, Caglayan HS, Arslan M, Pena SDJ, Sisodiya SM, Balestrini S, Syrbe S, Veggiotti P, Lemke JR, Møller RS, Lerche H, Rubboli G. Clinical spectrum and genotype-phenotype associations of KCNA2-related encephalopathies. Brain 2017; 140:2337-2354. [PMID: 29050392 DOI: 10.1093/brain/awx184] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 06/06/2017] [Indexed: 11/14/2022] Open
Abstract
Recently, de novo mutations in the gene KCNA2, causing either a dominant-negative loss-of-function or a gain-of-function of the voltage-gated K+ channel Kv1.2, were described to cause a new molecular entity within the epileptic encephalopathies. Here, we report a cohort of 23 patients (eight previously described) with epileptic encephalopathy carrying either novel or known KCNA2 mutations, with the aim to detail the clinical phenotype associated with each of them, to characterize the functional effects of the newly identified mutations, and to assess genotype-phenotype associations. We identified five novel and confirmed six known mutations, three of which recurred in three, five and seven patients, respectively. Ten mutations were missense and one was a truncation mutation; de novo occurrence could be shown in 20 patients. Functional studies using a Xenopus oocyte two-microelectrode voltage clamp system revealed mutations with only loss-of-function effects (mostly dominant-negative current amplitude reduction) in eight patients or only gain-of-function effects (hyperpolarizing shift of voltage-dependent activation, increased amplitude) in nine patients. In six patients, the gain-of-function was diminished by an additional loss-of-function (gain-and loss-of-function) due to a hyperpolarizing shift of voltage-dependent activation combined with either decreased amplitudes or an additional hyperpolarizing shift of the inactivation curve. These electrophysiological findings correlated with distinct phenotypic features. The main differences were (i) predominant focal (loss-of-function) versus generalized (gain-of-function) seizures and corresponding epileptic discharges with prominent sleep activation in most cases with loss-of-function mutations; (ii) more severe epilepsy, developmental problems and ataxia, and atrophy of the cerebellum or even the whole brain in about half of the patients with gain-of-function mutations; and (iii) most severe early-onset phenotypes, occasionally with neonatal onset epilepsy and developmental impairment, as well as generalized and focal seizures and EEG abnormalities for patients with gain- and loss-of-function mutations. Our study thus indicates well represented genotype-phenotype associations between three subgroups of patients with KCNA2 encephalopathy according to the electrophysiological features of the mutations.
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Affiliation(s)
- Silvia Masnada
- Brain and Behaviour Department, University of Pavia, Italy.,Department of Child Neurology and Psychiatry, IRCCS C. Mondino National Neurological Institute, Pavia, Italy.,Danish Epilepsy Centre, Dianalund, Denmark
| | - Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie Institute of Clinical Brain Research, University of Tübingen, Germany
| | - Elena Gardella
- Clinical Neurophysiology, Danish Epilepsy Centre, Dianalund, Denmark.,Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Julian Schubert
- Department of Neurology and Epileptology, Hertie Institute of Clinical Brain Research, University of Tübingen, Germany
| | - Charu Kaiwar
- Center for Individualized Medicine, Mayo Clinic, Scottsdale AZ, USA
| | - Eric W Klee
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA
| | | | - Ralitza H Gavrilova
- Departments of Clinical Genomics and Neurology Mayo Clinic, Rochester, MN, USA
| | - Matthis Synofzik
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research (HIH), University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | | | - Kathleen Gorman
- Department of Neurology and Clinical Neurophysiology, Children's University Hospital, Temple Street, Dublin, Ireland.,Academic Centre on Rare Diseases, School of Medicine and Medical Science, University College Dublin, Ireland
| | - Mary D King
- Department of Neurology and Clinical Neurophysiology, Children's University Hospital, Temple Street, Dublin, Ireland.,Academic Centre on Rare Diseases, School of Medicine and Medical Science, University College Dublin, Ireland
| | - Nicholas M Allen
- Department of Neurology and Clinical Neurophysiology, Children's University Hospital, Temple Street, Dublin, Ireland.,Academic Centre on Rare Diseases, School of Medicine and Medical Science, University College Dublin, Ireland
| | - Judith Conroy
- Academic Centre on Rare Diseases, School of Medicine and Medical Science, University College Dublin, Ireland
| | - Bruria Ben Zeev
- Sackler school of medicine Tel Aviv University, Tel Aviv, Israel
| | - Michal Tzadok
- Pediatric Neurology Unit, Sheba Medical Center, Israel
| | - Christian Korff
- Pediatric Neurology University Hospitals, Geneva, Switzerland
| | | | - Keri Ramsey
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, USA.,Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, USA.,Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Jose M Serratosa
- Neurology Laboratory and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Beatriz G Giraldez
- Neurology Laboratory and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Ingo Helbig
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, USA.,Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Kiel Germany
| | - Eric Marsh
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, USA
| | - Margaret O'Brien
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, USA
| | | | - Adrian Binelli
- Department of Pediatric Neurology, Elizalde Children's Hospital, Buenos Aires, Argentina.,Sociedad Argentina de Neurología Infantil (SANI) / Argentinian Child Neurology Society
| | - Brenda Porter
- Department of Neurology and Neurological Sciences, Stanford University, Palo Alto California, USA
| | - Eduardo Zaeyen
- Neuropediatrics Committee of State of Rio De Janeiro, Rio De Janeiro, Brazil
| | - Dafne D Horovitz
- Medical Genetics Department, National Institute for Women, Children and Adolescents Health Fernandes Figueira - Fiocruz, Rio de Janeiro, Brazil
| | - Markus Wolff
- Department of Pediatric Neurology and Developmental Medecine, University Children's Hospital, Tübingen, Germany
| | | | - Hande S Caglayan
- Department of Molecular Biology and Genetics, Bogazici University, Istanbul, Turkey
| | - Mutluay Arslan
- Department of Pediatric Neurology, Gulhane Military Medical School, Ankara, Turkey
| | - Sergio D J Pena
- GENE - Núcleo de Genética Médica, Belo Horizonte, MG, Brazil
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology and Epilepsy Society, UK
| | - Simona Balestrini
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology and Epilepsy Society, UK
| | - Steffen Syrbe
- Department of General Paediatrics, Division of Child Neurology and Inherited Metabolic Diseases, Centre for Paediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany.,Department of Women and Child Health, Hospital for Children and Adolescents, University of Leipzig Hospitals and Clinics, Leipzig, Germany
| | - Pierangelo Veggiotti
- Brain and Behaviour Department, University of Pavia, Italy.,Department of Child Neurology and Psychiatry, IRCCS C. Mondino National Neurological Institute, Pavia, Italy
| | | | - Rikke S Møller
- Danish Epilepsy Centre, Dianalund, Denmark.,Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute of Clinical Brain Research, University of Tübingen, Germany
| | - Guido Rubboli
- Danish Epilepsy Centre, Dianalund, Denmark.,University of Copenhagen, Copenhagen, Denmark
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Mishra V, Karumuri BK, Gautier NM, Liu R, Hutson TN, Vanhoof-Villalba SL, Vlachos I, Iasemidis L, Glasscock E. Scn2a deletion improves survival and brain-heart dynamics in the Kcna1-null mouse model of sudden unexpected death in epilepsy (SUDEP). Hum Mol Genet 2017; 26:2091-2103. [PMID: 28334922 DOI: 10.1093/hmg/ddx104] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/13/2017] [Indexed: 12/20/2022] Open
Abstract
People with epilepsy have greatly increased probability of premature mortality due to sudden unexpected death in epilepsy (SUDEP). Identifying which patients are most at risk of SUDEP is hindered by a complex genetic etiology, incomplete understanding of the underlying pathophysiology and lack of prognostic biomarkers. Here we evaluated heterozygous Scn2a gene deletion (Scn2a+/-) as a protective genetic modifier in the Kcna1 knockout mouse (Kcna1-/-) model of SUDEP, while searching for biomarkers of SUDEP risk embedded in electroencephalography (EEG) and electrocardiography (ECG) recordings. The human epilepsy gene Kcna1 encodes voltage-gated Kv1.1 potassium channels that act to dampen neuronal excitability whereas Scn2a encodes voltage-gated Nav1.2 sodium channels important for action potential initiation and conduction. SUDEP-prone Kcna1-/- mice with partial genetic ablation of Nav1.2 channels (i.e. Scn2a+/-; Kcna1-/-) exhibited a two-fold increase in survival. Classical analysis of EEG and ECG recordings separately showed significantly decreased seizure durations in Scn2a+/-; Kcna1-/- mice compared with Kcna1-/- mice, without substantial modification of cardiac abnormalities. Novel analysis of the EEG and ECG together revealed a significant reduction in EEG-ECG association in Kcna1-/- mice compared with wild types, which was partially restored in Scn2a+/-; Kcna1-/- mice. The degree of EEG-ECG association was also proportional to the survival rate of mice across genotypes. These results show that Scn2a gene deletion acts as protective genetic modifier of SUDEP and suggest measures of brain-heart association as potential indices of SUDEP susceptibility.
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Affiliation(s)
- Vikas Mishra
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Bharat K Karumuri
- Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA
| | - Nicole M Gautier
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Rui Liu
- Department of Mathematics and Statistics, Louisiana Tech University, Ruston, LA 71272, USA
| | - Timothy N Hutson
- Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA
| | - Stephanie L Vanhoof-Villalba
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Ioannis Vlachos
- Department of Mathematics and Statistics, Louisiana Tech University, Ruston, LA 71272, USA
| | - Leonidas Iasemidis
- Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA
| | - Edward Glasscock
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
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Jiménez-Vargas JM, Possani LD, Luna-Ramírez K. Arthropod toxins acting on neuronal potassium channels. Neuropharmacology 2017; 127:139-160. [PMID: 28941737 DOI: 10.1016/j.neuropharm.2017.09.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 01/01/2023]
Abstract
Arthropod venoms are a rich mixture of biologically active compounds exerting different physiological actions across diverse phyla and affecting multiple organ systems including the central nervous system. Venom compounds can inhibit or activate ion channels, receptors and transporters with high specificity and affinity providing essential insights into ion channel function. In this review, we focus on arthropod toxins (scorpions, spiders, bees and centipedes) acting on neuronal potassium channels. A brief description of the K+ channels classification and structure is included and a compendium of neuronal K+ channels and the arthropod toxins that modify them have been listed. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Juana María Jiménez-Vargas
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad, 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - Lourival D Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad, 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - Karen Luna-Ramírez
- Illawarra Health and Medical Research Institute, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia.
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Baronas VA, Yang RY, Kurata HT. Extracellular redox sensitivity of Kv1.2 potassium channels. Sci Rep 2017; 7:9142. [PMID: 28831076 PMCID: PMC5567313 DOI: 10.1038/s41598-017-08718-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/17/2017] [Indexed: 12/03/2022] Open
Abstract
Kv1.2 is a prominent potassium channel subtype in the nervous system and serves as an important structural template for investigation of ion channel function. However, Kv1.2 voltage-dependence exhibits dramatic cell-to-cell variability due to a gating mode shift that is regulated by an unknown mechanism. We report that this variable behavior is regulated by the extracellular redox environment. Exposure to reducing agents promotes a shift in gating properties towards an 'inhibited' gating mode that resists opening, and causes channels to exhibit pronounced use-dependent activation during trains of repetitive depolarizations. This sensitivity to extracellular redox potential is absent in other Kv1 channels, but is apparent in heteromeric channels containing Kv1.2 subunits, and overlaps with the reported physiological range of extracellular redox couples. Mutagenesis of candidate cysteine residues fails to abolish redox sensitivity. Therefore, we suggest that an extrinsic, redox-sensitive binding partner imparts these properties.
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Affiliation(s)
- Victoria A Baronas
- Department of Pharmacology, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Runying Y Yang
- Department of Pharmacology, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Harley T Kurata
- Department of Pharmacology, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada.
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Tanner MR, Tajhya RB, Huq R, Gehrmann EJ, Rodarte KE, Atik MA, Norton RS, Pennington MW, Beeton C. Prolonged immunomodulation in inflammatory arthritis using the selective Kv1.3 channel blocker HsTX1[R14A] and its PEGylated analog. Clin Immunol 2017; 180:45-57. [PMID: 28389388 PMCID: PMC5484050 DOI: 10.1016/j.clim.2017.03.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/27/2017] [Accepted: 03/28/2017] [Indexed: 12/31/2022]
Abstract
Effector memory T lymphocytes (TEM cells) that lack expression of CCR7 are major drivers of inflammation in a number of autoimmune diseases, including multiple sclerosis and rheumatoid arthritis. The Kv1.3 potassium channel is a key regulator of CCR7- TEM cell activation. Blocking Kv1.3 inhibits TEM cell activation and attenuates inflammation in autoimmunity, and as such, Kv1.3 has emerged as a promising target for the treatment of TEM cell-mediated autoimmune diseases. The scorpion venom-derived peptide HsTX1 and its analog HsTX1[R14A] are potent Kv1.3 blockers and HsTX1[R14A] is selective for Kv1.3 over closely-related Kv1 channels. PEGylation of HsTX1[R14A] to create a Kv1.3 blocker with a long circulating half-life reduced its affinity but not its selectivity for Kv1.3, dramatically reduced its adsorption to inert surfaces, and enhanced its circulating half-life in rats. PEG-HsTX1[R14A] is equipotent to HsTX1[R14A] in preferential inhibition of human and rat CCR7- TEM cell proliferation, leaving CCR7+ naïve and central memory T cells able to proliferate. It reduced inflammation in an active delayed-type hypersensitivity model and in the pristane-induced arthritis (PIA) model of rheumatoid arthritis (RA). Importantly, a single subcutaneous dose of PEG-HsTX1[R14A] reduced inflammation in PIA for a longer period of time than the non-PEGylated HsTX1[R14A]. Together, these data indicate that HsTX1[R14A] and PEG-HsTX1[R14A] are effective in a model of RA and are therefore potential therapeutics for TEM cell-mediated autoimmune diseases. PEG-HsTX1[R14A] has the additional advantages of reduced non-specific adsorption to inert surfaces and enhanced circulating half-life.
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Affiliation(s)
- Mark R Tanner
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Interdepartmental Graduate Program in Translational Biology & Molecular Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Rajeev B Tajhya
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Redwan Huq
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Elizabeth J Gehrmann
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kathia E Rodarte
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mustafa A Atik
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | | | - Christine Beeton
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Biology of Inflammation Center and Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA.
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Kleinecke S, Richert S, de Hoz L, Brügger B, Kungl T, Asadollahi E, Quintes S, Blanz J, McGonigal R, Naseri K, Sereda MW, Sachsenheimer T, Lüchtenborg C, Möbius W, Willison H, Baes M, Nave KA, Kassmann CM. Peroxisomal dysfunctions cause lysosomal storage and axonal Kv1 channel redistribution in peripheral neuropathy. eLife 2017; 6. [PMID: 28470148 PMCID: PMC5417850 DOI: 10.7554/elife.23332] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 04/06/2017] [Indexed: 12/12/2022] Open
Abstract
Impairment of peripheral nerve function is frequent in neurometabolic diseases, but mechanistically not well understood. Here, we report a novel disease mechanism and the finding that glial lipid metabolism is critical for axon function, independent of myelin itself. Surprisingly, nerves of Schwann cell-specific Pex5 mutant mice were unaltered regarding axon numbers, axonal calibers, and myelin sheath thickness by electron microscopy. In search for a molecular mechanism, we revealed enhanced abundance and internodal expression of axonal membrane proteins normally restricted to juxtaparanodal lipid-rafts. Gangliosides were altered and enriched within an expanded lysosomal compartment of paranodal loops. We revealed the same pathological features in a mouse model of human Adrenomyeloneuropathy, preceding disease-onset by one year. Thus, peroxisomal dysfunction causes secondary failure of local lysosomes, thereby impairing the turnover of gangliosides in myelin. This reveals a new aspect of axon-glia interactions, with Schwann cell lipid metabolism regulating the anchorage of juxtaparanodal Kv1-channels. DOI:http://dx.doi.org/10.7554/eLife.23332.001 Nerve cells transmit messages along their length in the form of electrical signals. Much like an electrical wire, the nerve fiber or axon is coated by a multiple-layered insulation, called the myelin sheath. However, unlike electrical insulation, the myelin sheath is regularly interrupted to expose short regions of the underlying nerve. These exposed regions and the adjacent regions underneath the myelin contain ion channels that help to propagate electrical signals along the axon. Peroxisomes are compartments in animal cells that process fats. Genetic mutations that prevent peroxisomes from working properly can lead to diseases where the nerves cannot transmit signals correctly. This is thought to be because the nerves lose their myelin sheath, which largely consists of fatty molecules. The nerves outside of the brain and spinal cord are known as peripheral nerves. Kleinecke et al. have now analyzed peripheral nerves from mice that had one of three different genetic mutations, preventing their peroxisomes from working correctly. Even in cases where the mutation severely impaired nerve signaling, the peripheral nerves retained their myelin sheath. The peroxisome mutations did affect a particular type of potassium ion channel and the anchor proteins that hold these channels in place. The role of these potassium ion channels is not fully known, but normally they are only found close to regions of the axon that are not coated by myelin. However, the peroxisome mutations meant that the channels and their protein anchors were now also located along the myelinated segments of the nerve’s axons. This redistribution of the potassium ion channels likely contributes to the peripheral nerves being unable to signal properly. In addition, Kleinecke et al. found that disrupting the peroxisomes also affected another cell compartment, called the lysosome, in the nerve cells that insulate axons with myelin sheaths. Lysosomes help to break down unwanted fat molecules. Mutant mice had more lysosomes than normal, but these lysosomes did not work efficiently. This caused the nerve cells to store more of certain types of molecules, including molecules called glycolipids that stabilize protein anchors, which hold the potassium channels in place. A likely result is that protein anchors that would normally be degraded are not, leading to the potassium channels appearing inappropriately throughout the nerve. Future work is now needed to investigate whether peroxisomal diseases cause similar changes in the brain. The results presented by Kleinecke et al. also suggest that targeting the lysosomes or the potassium channels could present new ways to treat disorders of the peroxisomes. DOI:http://dx.doi.org/10.7554/eLife.23332.002
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Affiliation(s)
- Sandra Kleinecke
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Sarah Richert
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Livia de Hoz
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Britta Brügger
- University of Heidelberg, Biochemistry Center (BZH), Heidelberg, Germany
| | - Theresa Kungl
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ebrahim Asadollahi
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Susanne Quintes
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Judith Blanz
- Unit of Molecular Cell Biology and Transgenic, Institute of Biochemistry, University of Kiel, Kiel, Germany
| | - Rhona McGonigal
- Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Kobra Naseri
- Birjand University of Medical Sciences, Birjand, Iran
| | - Michael W Sereda
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Timo Sachsenheimer
- University of Heidelberg, Biochemistry Center (BZH), Heidelberg, Germany
| | | | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Hugh Willison
- Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Myriam Baes
- Department of Pharmaceutical and Pharmacological Sciences, Cell Metabolism, KU Leuven- University of Leuven, Leuven, Belgium
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Celia Michèle Kassmann
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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Mutations underlying Episodic Ataxia type-1 antagonize Kv1.1 RNA editing. Sci Rep 2017; 7:41095. [PMID: 28216637 PMCID: PMC5316942 DOI: 10.1038/srep41095] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/14/2016] [Indexed: 11/08/2022] Open
Abstract
Adenosine-to-inosine RNA editing in transcripts encoding the voltage-gated potassium channel Kv1.1 converts an isoleucine to valine codon for amino acid 400, speeding channel recovery from inactivation. Numerous Kv1.1 mutations have been associated with the human disorder Episodic Ataxia Type-1 (EA1), characterized by stress-induced ataxia, myokymia, and increased prevalence of seizures. Three EA1 mutations, V404I, I407M, and V408A, are located within the RNA duplex structure required for RNA editing. Each mutation decreased RNA editing both in vitro and using an in vivo mouse model bearing the V408A allele. Editing of transcripts encoding mutant channels affects numerous biophysical properties including channel opening, closing, and inactivation. Thus EA1 symptoms could be influenced not only by the direct effects of the mutations on channel properties, but also by their influence on RNA editing. These studies provide the first evidence that mutations associated with human genetic disorders can affect cis-regulatory elements to alter RNA editing.
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Cao XJ, Oertel D. Genetic perturbations suggest a role of the resting potential in regulating the expression of the ion channels of the KCNA and HCN families in octopus cells of the ventral cochlear nucleus. Hear Res 2017; 345:57-68. [PMID: 28065805 DOI: 10.1016/j.heares.2017.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/02/2017] [Accepted: 01/03/2017] [Indexed: 10/20/2022]
Abstract
Low-voltage-activated K+ (gKL) and hyperpolarization-activated mixed cation conductances (gh) mediate currents, IKL and Ih, through channels of the Kv1 (KCNA) and HCN families respectively and give auditory neurons the temporal precision required for signaling information about the onset, fine structure, and time of arrival of sounds. Being partially activated at rest, gKL and gh contribute to the resting potential and shape responses to even small subthreshold synaptic currents. Resting gKL and gh also affect the coupling of somatic depolarization with the generation of action potentials. To learn how these important conductances are regulated we have investigated how genetic perturbations affect their expression in octopus cells of the ventral cochlear nucleus (VCN). We report five new findings: First, the magnitude of gh and gKL varied over more than two-fold between wild type strains of mice. Second, average resting potentials are not different in different strains of mice even in the face of large differences in average gKL and gh. Third, IKL has two components, one being α-dendrotoxin (α-DTX)-sensitive and partially inactivating and the other being α-DTX-insensitive, tetraethylammonium (TEA)-sensitive, and non-inactivating. Fourth, the loss of Kv1.1 results in diminution of the α-DTX-sensitive IKL, and compensatory increased expression of an α-DTX-insensitive, tetraethylammonium (TEA)-sensitive IKL. Fifth, Ih and IKL are balanced at the resting potential in all wild type and mutant octopus cells even when resting potentials vary in individual cells over nearly 10 mV, indicating that the resting potential influences the expression of gh and gKL. The independence of resting potentials on gKL and gh shows that gKL and gh do not, over days or weeks, determine the resting potential but rather that the resting potential plays a role in regulating the magnitude of either or both gKL and gh.
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Affiliation(s)
- Xiao-Jie Cao
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA
| | - Donata Oertel
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA.
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Abstract
Classic hallucinogens share pharmacology as serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonists. Unique among most other Schedule 1 drugs, they are generally non-addictive and can be effective tools in the treatment of addiction. Mechanisms underlying these attributes are largely unknown. However, many preclinical studies show that 5-HT2C agonists counteract the addictive effects of drugs from several classes, suggesting this pharmacological property of classic hallucinogens may be significant. Drawing from a comprehensive analysis of preclinical behavior, neuroanatomy, and neurochemistry studies, this review builds rationale for this hypothesis, and also proposes a testable, neurobiological framework. 5-HT2C agonists work, in part, by modulating dopamine neuron activity in the ventral tegmental area-nucleus accumbens (NAc) reward pathway. We argue that activation of 5-HT2C receptors on NAc shell, GABAergic, medium spiny neurons inhibits potassium Kv1.x channels, thereby enhancing inhibitory activity via intrinsic mechanisms. Together with experiments that show that addictive drugs, such as cocaine, potentiate Kv1.x channels, thereby suppressing NAc shell GABAergic activity, this hypothesis provides a mechanism by which classic hallucinogen-mediated stimulation of 5-HT2C receptors could thwart addiction. It also provides a potential reason for the non-addictive nature of classic hallucinogens.
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Affiliation(s)
- Clinton E Canal
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, USA
| | - Kevin S Murnane
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, USA
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Parrini E, Marini C, Mei D, Galuppi A, Cellini E, Pucatti D, Chiti L, Rutigliano D, Bianchini C, Virdò S, De Vita D, Bigoni S, Barba C, Mari F, Montomoli M, Pisano T, Rosati A, Guerrini R. Diagnostic Targeted Resequencing in 349 Patients with Drug-Resistant Pediatric Epilepsies Identifies Causative Mutations in 30 Different Genes. Hum Mutat 2016; 38:216-225. [DOI: 10.1002/humu.23149] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/13/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Elena Parrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Carla Marini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Davide Mei
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Anna Galuppi
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Elena Cellini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Daniela Pucatti
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Laura Chiti
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Domenico Rutigliano
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Claudia Bianchini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Simona Virdò
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Dalila De Vita
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Stefania Bigoni
- UOL of Medical Genetics; Ferrara University Hospital; Ferrara Italy
| | - Carmen Barba
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Francesco Mari
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Martino Montomoli
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Tiziana Pisano
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Anna Rosati
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
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Corbett MA, Bellows ST, Li M, Carroll R, Micallef S, Carvill GL, Myers CT, Howell KB, Maljevic S, Lerche H, Gazina EV, Mefford HC, Bahlo M, Berkovic SF, Petrou S, Scheffer IE, Gecz J. Dominant KCNA2 mutation causes episodic ataxia and pharmacoresponsive epilepsy. Neurology 2016; 87:1975-1984. [PMID: 27733563 DOI: 10.1212/wnl.0000000000003309] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 07/26/2016] [Indexed: 01/14/2023] Open
Abstract
OBJECTIVE To identify the genetic basis of a family segregating episodic ataxia, infantile seizures, and heterogeneous epilepsies and to study the phenotypic spectrum of KCNA2 mutations. METHODS A family with 7 affected individuals over 3 generations underwent detailed phenotyping. Whole genome sequencing was performed on a mildly affected grandmother and her grandson with epileptic encephalopathy (EE). Segregating variants were filtered and prioritized based on functional annotations. The effects of the mutation on channel function were analyzed in vitro by voltage clamp assay and in silico by molecular modeling. KCNA2 was sequenced in 35 probands with heterogeneous phenotypes. RESULTS The 7 family members had episodic ataxia (5), self-limited infantile seizures (5), evolving to genetic generalized epilepsy (4), focal seizures (2), and EE (1). They had a segregating novel mutation in the shaker type voltage-gated potassium channel KCNA2 (CCDS_827.1: c.765_773del; p.255_257del). A rare missense SCN2A (rs200884216) variant was also found in 2 affected siblings and their unaffected mother. The p.255_257del mutation caused dominant negative loss of channel function. Molecular modeling predicted repositioning of critical arginine residues in the voltage-sensing domain. KCNA2 sequencing revealed 1 de novo mutation (CCDS_827.1: c.890G>A; p.Arg297Gln) in a girl with EE, ataxia, and tremor. CONCLUSIONS A KCNA2 mutation caused dominantly inherited episodic ataxia, mild infantile-onset seizures, and later generalized and focal epilepsies in the setting of normal intellect. This observation expands the KCNA2 phenotypic spectrum from EE often associated with chronic ataxia, reflecting the marked variation in severity observed in many ion channel disorders.
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Affiliation(s)
- Mark A Corbett
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Susannah T Bellows
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Melody Li
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Renée Carroll
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Silvana Micallef
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Gemma L Carvill
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Candace T Myers
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Katherine B Howell
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Snezana Maljevic
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Holger Lerche
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Elena V Gazina
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Heather C Mefford
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Melanie Bahlo
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Samuel F Berkovic
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Steven Petrou
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia
| | - Ingrid E Scheffer
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia.
| | - Jozef Gecz
- From the School of Medicine and Robinson Research Institute (M.A.C., R.C., J.G.) and School of Biological Sciences (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (S.T.B., S. Micallef, S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg; Florey Institute of Neuroscience and Mental Health (M.L., S. Maljevic, E.V.G., S.P., I.E.S.), Melbourne; Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.T.M., H.C.M.), University of Washington, Seattle; Department of Neurology (K.B.H., I.E.S.), Royal Children's Hospital; Neurosciences Group (K.B.H.), Murdoch Childrens Research Institute, Melbourne; Department of Paediatrics (K.B.H.), University of Melbourne, Royal Children's Hospital, Parkville, Australia; Department of Neurology and Epileptology (S. Maljevic, H.L.), Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; The Walter and Eliza Hall Institute of Medical Research (M.B.); Department of Medical Biology (M.B.), The University of Melbourne, Parkville; and Department of Medicine, Royal Melbourne Hospital (S.P.), The University of Melbourne, Australia.
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