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Groulx-Boivin E, Bouchet T, Myers KA. Understanding of Consciousness in Absence Seizures: A Literature Review. Neuropsychiatr Dis Treat 2024; 20:1345-1353. [PMID: 38947367 PMCID: PMC11212660 DOI: 10.2147/ndt.s391052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 06/14/2024] [Indexed: 07/02/2024] Open
Abstract
Absence seizures are classically associated with behavioral arrest and transient deficits in consciousness, yet substantial variability exists in the severity of the impairment. Despite several decades of research on the topic, the pathophysiology of absence seizures and the mechanisms underlying behavioral impairment remain unclear. Several rationales have been proposed including widespread cortical deactivation, reduced perception of external stimuli, and transient suspension of the default mode network, among others. This review aims to summarize the current knowledge on the neural correlates of impaired consciousness in absence seizures. We review evidence from studies using animal models of absence epilepsy, electroencephalography, functional magnetic resonance imaging, magnetoencephalography, positron emission tomography, and single photon emission computed tomography.
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Affiliation(s)
- Emilie Groulx-Boivin
- Department of Neurology and Neurosurgery, Montreal Children’s Hospital, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, Montreal Children’s Hospital, McGill University, Montreal, Quebec, Canada
| | - Tasha Bouchet
- Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Kenneth A Myers
- Department of Neurology and Neurosurgery, Montreal Children’s Hospital, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, Montreal Children’s Hospital, McGill University, Montreal, Quebec, Canada
- Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec, Canada
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2
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Ng ACH, Chahine M, Scantlebury MH, Appendino JP. Channelopathies in epilepsy: an overview of clinical presentations, pathogenic mechanisms, and therapeutic insights. J Neurol 2024; 271:3063-3094. [PMID: 38607431 DOI: 10.1007/s00415-024-12352-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
Pathogenic variants in genes encoding ion channels are causal for various pediatric and adult neurological conditions. In particular, several epilepsy syndromes have been identified to be caused by specific channelopathies. These encompass a spectrum from self-limited epilepsies to developmental and epileptic encephalopathies spanning genetic and acquired causes. Several of these channelopathies have exquisite responses to specific antiseizure medications (ASMs), while others ASMs may prove ineffective or even worsen seizures. Some channelopathies demonstrate phenotypic pleiotropy and can cause other neurological conditions outside of epilepsy. This review aims to provide a comprehensive exploration of the pathophysiology of seizure generation, ion channels implicated in epilepsy, and several genetic epilepsies due to ion channel dysfunction. We outline the clinical presentation, pathogenesis, and the current state of basic science and clinical research for these channelopathies. In addition, we briefly look at potential precision therapy approaches emerging for these disorders.
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Affiliation(s)
- Andy Cheuk-Him Ng
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Division of Neurology, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta and Stollery Children's Hospital, Edmonton, AB, Canada
| | - Mohamed Chahine
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
- CERVO, Brain Research Centre, Quebec City, Canada
| | - Morris H Scantlebury
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Calgary, Canada
| | - Juan P Appendino
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada.
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3
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Huang J, Fan X, Jin X, Lyu C, Guo Q, Liu T, Chen J, Davakan A, Lory P, Yan N. Structural basis for human Ca v3.2 inhibition by selective antagonists. Cell Res 2024; 34:440-450. [PMID: 38605177 PMCID: PMC11143251 DOI: 10.1038/s41422-024-00959-8] [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: 12/21/2023] [Accepted: 04/02/2024] [Indexed: 04/13/2024] Open
Abstract
The Cav3.2 subtype of T-type calcium channels has been targeted for developing analgesics and anti-epileptics for its role in pain and epilepsy. Here we present the cryo-EM structures of Cav3.2 alone and in complex with four T-type calcium channel selective antagonists with overall resolutions ranging from 2.8 Å to 3.2 Å. The four compounds display two binding poses. ACT-709478 and TTA-A2 both place their cyclopropylphenyl-containing ends in the central cavity to directly obstruct ion flow, meanwhile extending their polar tails into the IV-I fenestration. TTA-P2 and ML218 project their 3,5-dichlorobenzamide groups into the II-III fenestration and place their hydrophobic tails in the cavity to impede ion permeation. The fenestration-penetrating mode immediately affords an explanation for the state-dependent activities of these antagonists. Structure-guided mutational analysis identifies several key residues that determine the T-type preference of these drugs. The structures also suggest the role of an endogenous lipid in stabilizing drug binding in the central cavity.
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Affiliation(s)
- Jian Huang
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Xiao Fan
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
- Laboratory of Neurophysiology and Behavior, The Rockefeller University, New York, NY, USA.
| | - Xueqin Jin
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Chen Lyu
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qinmeng Guo
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Tao Liu
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jiaofeng Chen
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Amaël Davakan
- IGF, Université de Montpellier, CNRS, INSERM, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Philippe Lory
- IGF, Université de Montpellier, CNRS, INSERM, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Nieng Yan
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.
- Institute of Bio-Architecture and Bio-Interactions, Shenzhen Medical Academy of Research and Translation, Shenzhen, Guangdong, China.
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4
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Szymanowicz O, Drużdż A, Słowikowski B, Pawlak S, Potocka E, Goutor U, Konieczny M, Ciastoń M, Lewandowska A, Jagodziński PP, Kozubski W, Dorszewska J. A Review of the CACNA Gene Family: Its Role in Neurological Disorders. Diseases 2024; 12:90. [PMID: 38785745 PMCID: PMC11119137 DOI: 10.3390/diseases12050090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 04/25/2024] [Accepted: 04/28/2024] [Indexed: 05/25/2024] Open
Abstract
Calcium channels are specialized ion channels exhibiting selective permeability to calcium ions. Calcium channels, comprising voltage-dependent and ligand-gated types, are pivotal in neuronal function, with their dysregulation is implicated in various neurological disorders. This review delves into the significance of the CACNA genes, including CACNA1A, CACNA1B, CACNA1C, CACNA1D, CACNA1E, CACNA1G, and CACNA1H, in the pathogenesis of conditions such as migraine, epilepsy, cerebellar ataxia, dystonia, and cerebellar atrophy. Specifically, variants in CACNA1A have been linked to familial hemiplegic migraine and epileptic seizures, underscoring its importance in neurological disease etiology. Furthermore, different genetic variants of CACNA1B have been associated with migraine susceptibility, further highlighting the role of CACNA genes in migraine pathology. The complex relationship between CACNA gene variants and neurological phenotypes, including focal seizures and ataxia, presents a variety of clinical manifestations of impaired calcium channel function. The aim of this article was to explore the role of CACNA genes in various neurological disorders, elucidating their significance in conditions such as migraine, epilepsy, and cerebellar ataxias. Further exploration of CACNA gene variants and their interactions with molecular factors, such as microRNAs, holds promise for advancing our understanding of genetic neurological disorders.
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Affiliation(s)
- Oliwia Szymanowicz
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (O.S.); (S.P.); (E.P.); (U.G.); (M.K.); (M.C.); (A.L.)
| | - Artur Drużdż
- Department of Neurology, Municipal Hospital in Poznan, 61-285 Poznan, Poland;
| | - Bartosz Słowikowski
- Department of Biochemistry and Molecular Biology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (B.S.); (P.P.J.)
| | - Sandra Pawlak
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (O.S.); (S.P.); (E.P.); (U.G.); (M.K.); (M.C.); (A.L.)
| | - Ewelina Potocka
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (O.S.); (S.P.); (E.P.); (U.G.); (M.K.); (M.C.); (A.L.)
| | - Ulyana Goutor
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (O.S.); (S.P.); (E.P.); (U.G.); (M.K.); (M.C.); (A.L.)
| | - Mateusz Konieczny
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (O.S.); (S.P.); (E.P.); (U.G.); (M.K.); (M.C.); (A.L.)
| | - Małgorzata Ciastoń
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (O.S.); (S.P.); (E.P.); (U.G.); (M.K.); (M.C.); (A.L.)
| | - Aleksandra Lewandowska
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (O.S.); (S.P.); (E.P.); (U.G.); (M.K.); (M.C.); (A.L.)
| | - Paweł P. Jagodziński
- Department of Biochemistry and Molecular Biology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (B.S.); (P.P.J.)
| | - Wojciech Kozubski
- Department of Neurology, Poznan University of Medical Sciences, 61-701 Poznan, Poland;
| | - Jolanta Dorszewska
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, 61-701 Poznan, Poland; (O.S.); (S.P.); (E.P.); (U.G.); (M.K.); (M.C.); (A.L.)
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5
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Lin ZJ, Li B, Lin PX, Song W, Yan LM, Meng H, He N. Clinical application of trio-based whole-exome sequencing in idiopathic generalized epilepsy. Seizure 2024; 116:24-29. [PMID: 36842888 DOI: 10.1016/j.seizure.2023.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/07/2023] [Accepted: 02/10/2023] [Indexed: 02/13/2023] Open
Abstract
PURPOSE Idiopathic generalized epilepsies (IGEs) are a common group of genetic generalized epilepsies with high genetic heterogeneity and complex inheritance. However, the genetic basis is still largely unknown. This study aimed to explore the genetic etiologies in IGEs. METHODS Trio-based whole-exome sequencing was performed in 60 cases with IGEs. The pathogenicity of candidate genetic variants was evaluated by the criteria of the American College of Medical Genetics and Genomics (ACMG), and the clinical causality was assessed by concordance between the observed phenotype and the reported phenotype. RESULTS Seven candidate variants were detected in seven unrelated cases with IGE (11.7%, 7/60). According to ACMG, a de novo SLC2A1 (c.376C>T/p.Arg126Cys) variant identified in childhood absence epilepsy was evaluated as pathogenic with clinical concordance. Six variants were assessed to be uncertain significance by ACMG, but then considered causative after evaluation of clinical concordance. These variants included CLCN4 hemizygous variant (c.2044G>A/p.Glu682Lys) and IQSEC2 heterozygous variant (c.4315C>T/p.Pro1439Ser) in juvenile absence epilepsy, EFHC1 variant (c.1504C>T/p.Arg502Trp) and CACNA1H (c.589G>T/p.Ala197Ser) both with incomplete penetrance in juvenile myoclonic epilepsy, and GRIN2A variant (c.2011C>G/p.Gln671Glu) and GABRB1 variant (c.1075G>A/p.Val359Ile) both co-segregated with juvenile myoclonic epilepsy. Among them, GABRB1 was for the first time identified as potential novel causative gene for IGE. SIGNIFICANCE Considering the genetic heterogeneity and complex inheritance of IGEs, a comprehensive evaluation combined the ACMG scoring and assessment of clinical concordance is suggested for the pathogenicity analysis of variants identified in clinical screening. GABRB1 is probably a novel causative gene for IGE, which warrants further studies.
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Affiliation(s)
- Zhi-Jian Lin
- Department of Neurology, the Affiliated Hospital of Putian University, Putian 351100, Fujian Province, China; Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Bin Li
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Peng-Xing Lin
- Department of Neurology, the Affiliated Hospital of Putian University, Putian 351100, Fujian Province, China
| | - Wang Song
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Li-Min Yan
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, 570311 Haikou, Hainan, China
| | - Heng Meng
- Department of Neurology, the First Affiliated Hospital of Jinan University, Guangzhou 510632, China.
| | - Na He
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.
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6
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Weiss N, Zamponi GW. The T-type calcium channelosome. Pflugers Arch 2024; 476:163-177. [PMID: 38036777 DOI: 10.1007/s00424-023-02891-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 12/02/2023]
Abstract
T-type calcium channels perform crucial physiological roles across a wide spectrum of tissues, spanning both neuronal and non-neuronal system. For instance, they serve as pivotal regulators of neuronal excitability, contribute to cardiac pacemaking, and mediate the secretion of hormones. These functions significantly hinge upon the intricate interplay of T-type channels with interacting proteins that modulate their expression and function at the plasma membrane. In this review, we offer a panoramic exploration of the current knowledge surrounding these T-type channel interactors, and spotlight certain aspects of their potential for drug-based therapeutic intervention.
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Affiliation(s)
- Norbert Weiss
- Department of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic.
| | - Gerald W Zamponi
- Department of Clinical Neurosciences, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
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7
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Liu N, Li J, Gao K, Perszyk RE, Zhang J, Wang J, Wu Y, Jenkins A, Yuan H, Traynelis SF, Jiang Y. De novo CLPTM1 variants with reduced GABA A R current response in patients with epilepsy. Epilepsia 2023; 64:2968-2981. [PMID: 37577761 PMCID: PMC10840799 DOI: 10.1111/epi.17746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 08/07/2023] [Accepted: 08/10/2023] [Indexed: 08/15/2023]
Abstract
OBJECTIVE To investigate the clinical features and potential pathogenesis mechanism of de novo CLPTM1 variants associated with epilepsy. METHODS Identify de novo genetic variants associated with epilepsy by reanalyzing trio-based whole-exome sequencing data. We analyzed the clinical characteristics of patients with these variants and performed functional in vitro studies in cells expressing mutant complementary DNA for these variants using whole-cell voltage-clamp current recordings and outside-out patch-clamp recordings from transiently transfected human embryonic kidney (HEK) cells. RESULTS Two de novo missense variants related to epilepsy were identified in the CLPTM1 gene. Functional studies indicated that CLPTM1-p.R454H and CLPTM1-p.R568Q variants reduced the γ-aminobutyric acid A receptor (GABAA R) current response amplitude recorded under voltage clamp compared to the wild-type receptors. These variants also reduced the charge transfer and altered the time course of desensitization and deactivation following rapid removal of GABA. The surface expression of the GABAA R γ2 subunit from the CLPTM1-p.R568Q group was significantly reduced compared to CLPTM1-WT. SIGNIFICANCE This is the first report of functionally relevant variants within the CLPTM1 gene. Patch-clamp recordings showed that these de novo CLPTM1 variants reduce GABAA R currents and charge transfer, which should promote excitation and hypersynchronous activity. This study may provide insights into the molecular mechanisms of the CLPTM1 variants underlying the patients' phenotypes, as well as for exploring potential therapeutic targets for epilepsy.
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Affiliation(s)
- Nana Liu
- 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
| | - Jinliang Li
- Department of Pediatrics, Central People's Hospital of Zhanjiang, Guangdong, China
| | - Kai Gao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China
- Children Epilepsy Center, Peking University First Hospital, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
| | - Riley E Perszyk
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jing Zhang
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jingmin Wang
- 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
- Department of Neurology, Affiliated Children's Hospital of Capital Institute of Pediatrics, Beijing, China
| | - Ye Wu
- 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
| | - Andrew Jenkins
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Pharmaceutical Sciences, University of Saint Joseph, West Hartford, Connecticut, USA
| | - Hongjie Yuan
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, Georgia, USA
| | - Stephen F Traynelis
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, Georgia, USA
| | - 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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Lauerer RJ, Lerche H. Voltage-gated calcium channels in genetic epilepsies. J Neurochem 2023. [PMID: 37822150 DOI: 10.1111/jnc.15983] [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: 07/08/2023] [Revised: 09/17/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
Voltage-gated calcium channels (VGCC) are abundant in the central nervous system and serve a broad spectrum of functions, either directly in cellular excitability or indirectly to regulate Ca2+ homeostasis. Ca2+ ions act as one of the main connections in excitation-transcription coupling, muscle contraction and excitation-exocytosis coupling, including synaptic transmission. In recent years, many genes encoding VGCCs main α or additional auxiliary subunits have been associated with epilepsy. This review sums up the current state of knowledge on disease mechanisms and provides guidance on disease-specific therapies where applicable.
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Affiliation(s)
- Robert J Lauerer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University and University Hospital Tuebingen, Tuebingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University and University Hospital Tuebingen, Tuebingen, Germany
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Casillas-Espinosa PM, Lin R, Li R, Nandakumar NM, Dawson G, Braine EL, Martin B, Powell KL, O'Brien TJ. Effects of the T-type calcium channel Ca V3.2 R1584P mutation on absence seizure susceptibility in GAERS and NEC congenic rats models. Neurobiol Dis 2023:106217. [PMID: 37391087 DOI: 10.1016/j.nbd.2023.106217] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 06/13/2023] [Accepted: 06/27/2023] [Indexed: 07/02/2023] Open
Abstract
RATIONALE Low-voltage-activated or T-type Ca2+ channels play a key role in the generation of seizures in absence epilepsy. We have described a homozygous, gain of function substitution mutation (R1584P) in the CaV3.2 T-type Ca2+ channel gene (Cacna1h) in the Genetic Absence Epilepsy Rats from Strasbourg (GAERS). The non-epileptic control (NEC) rats, derived from the same original Wistar strains as GAERS but selectively in-breed not to express seizures, are null for the R1584P mutation. To study the effects of this mutation in rats who otherwise have a GAERS or NEC genetic background, we bred congenic GAERS-Cacna1hNEC (GAERS null for R1584P mutation) and congenic NEC-Cacna1hGAERS (NEC homozygous for R1584P mutation) and evaluated the seizure and behavioral phenotype of these strains in comparison to the original GAERS and NEC strains. METHODS To evaluate seizure expression in the congenic strains, EEG electrodes were implanted in NEC, GAERS, GAERS-Cacna1hNEC without the R1584P mutation, and NEC-Cacna1hGAERS with the R1584P mutation rats. In the first study, continuous EEG recordings were acquired from week 4 (when seizures begin to develop in GAERS) to week 14 of age (when GAERS display hundreds of seizures per day). In the second study, the seizure and behavioral phenotype of GAERS and NEC-Cacna1hGAERS strains were evaluated during young age (6 weeks of age) and adulthood (16 weeks of age) of GAERS, NEC, GAERS-Cacna1hNEC and NEC-Cacna1hGAERS. The Open field test (OFT) and sucrose preference test (SPT) were performed to evaluate anxiety-like and depressive-like behavior, respectively. This was followed by EEG recordings at 18 weeks of age to quantify the seizures, and spike-wave discharge (SWD) cycle frequency. At the end of the study, the whole thalamus was collected for T-type calcium channel mRNA expression analysis. RESULTS GAERS had a significantly shorter latency to first seizures and an increased number of seizures per day compared to GAERS-Cacna1hNEC. On the other hand, the presence of the R1584P mutation in the NEC-Cacna1hGAERS was not enough to generate spontaneous seizures in their seizure-resistant background. 6 and 16-week-old GAERS and GAERS-Cacna1hNEC rats showed anxiety-like behavior in the OFT, in contrast to NEC and NEC-Cacna1hGAERS. Results from the SPT showed that the GAERS developed depressive-like in the SPT compared to GAERS-Cacna1hNEC, NEC, and NEC-Cacna1hGAERS. Analysis of the EEG at 18 weeks of age showed that the GAERS had an increased number of seizures per day, increased total seizure duration and a higher cycle frequency of SWD relative to GAERS-Cacna1hNEC. However, the average seizure duration was not significantly different between strains. Quantitative real-time PCR showed that the T-type Ca2+ channel isoform CaV3.2 channel expression was significantly increased in GAERS compared to NEC, GAERS-Cacna1hNEC and NEC-Cacna1hGAERS. The presence of the R1584P mutation increased the total ratio of CaV3.2 + 25/-25 splice variants in GAERS and NEC-Cacna1hGAERS compared to NEC and GAERS-Cacna1hNEC. DISCUSSION The data from this study demonstrate that the R1584P mutation in isolation on a seizure-resistant NEC genetic background was insufficient to generate absence seizures, and that a GAERS genetic background can cause seizures even without the mutation. However, the study provides evidence that the R1584P mutation acts as a modulator of seizures development and expression, and depressive-like behavior in the SPT, but not the anxiety phenotype of the GAERS model of absence epilepsy.
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Affiliation(s)
- Pablo M Casillas-Espinosa
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Victoria, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Royal Parade, Parkville, Victoria 3050, Australia; Department of Neurology, The Alfred Hospital, Commercial Road, Melbourne, Victoria, 3004, Victoria, Australia.
| | - Runxuan Lin
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Victoria, Australia
| | - Rui Li
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Victoria, Australia
| | - Nanditha M Nandakumar
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Victoria, Australia
| | - Georgia Dawson
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Victoria, Australia
| | - Emma L Braine
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Victoria, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Royal Parade, Parkville, Victoria 3050, Australia
| | - Benoît Martin
- Univ Rennes, INSERM, LTSI - UMR 1099, F-35000 Rennes, France
| | - Kim L Powell
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Victoria, Australia
| | - Terence J O'Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Victoria, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Royal Parade, Parkville, Victoria 3050, Australia; Department of Neurology, The Alfred Hospital, Commercial Road, Melbourne, Victoria, 3004, Victoria, Australia.
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10
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Mayo S, Gómez-Manjón I, Marco-Hernández AV, Fernández-Martínez FJ, Camacho A, Martínez F. N-Type Ca Channel in Epileptic Syndromes and Epilepsy: A Systematic Review of Its Genetic Variants. Int J Mol Sci 2023; 24:6100. [PMID: 37047073 PMCID: PMC10094502 DOI: 10.3390/ijms24076100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/20/2023] [Accepted: 03/22/2023] [Indexed: 04/14/2023] Open
Abstract
N-type voltage-gated calcium channel controls the release of neurotransmitters from neurons. The association of other voltage-gated calcium channels with epilepsy is well-known. The association of N-type voltage-gated calcium channels and pain has also been established. However, the relationship between this type of calcium channel and epilepsy has not been specifically reviewed. Therefore, the present review systematically summarizes existing publications regarding the genetic associations between N-type voltage-dependent calcium channel and epilepsy.
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Affiliation(s)
- Sonia Mayo
- Genetics and Inheritance Research Group, Instituto de Investigación Sanitaria Hospital 12 de Octubre, 28041 Madrid, Spain
- Department of Genetics, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Irene Gómez-Manjón
- Genetics and Inheritance Research Group, Instituto de Investigación Sanitaria Hospital 12 de Octubre, 28041 Madrid, Spain
- Department of Genetics, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Ana Victoria Marco-Hernández
- Neuropediatric Unit, Hospital Universitario Doctor Peset, 46017 Valencia, Spain
- Translational Research in Genetics, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
| | - Francisco Javier Fernández-Martínez
- Genetics and Inheritance Research Group, Instituto de Investigación Sanitaria Hospital 12 de Octubre, 28041 Madrid, Spain
- Department of Genetics, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Ana Camacho
- Division of Pediatric Neurology, Department of Neurology, Hospital Universitario 12 de Octubre, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Francisco Martínez
- Translational Research in Genetics, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
- Genomic Unit, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politecnico La Fe, 46026 Valencia, Spain
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11
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Jeong S, Shim JS, Sin SK, Park KS, Lee JH. Phosphorylation states greatly regulate the activity and gating properties of Ca v 3.1 T-type Ca 2+ channels. J Cell Physiol 2023; 238:210-226. [PMID: 36502489 DOI: 10.1002/jcp.30920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/21/2022] [Accepted: 11/10/2022] [Indexed: 12/14/2022]
Abstract
Cav 3.1 T-type Ca2+ channels play pivotal roles in neuronal low-threshold spikes, visceral pain, and pacemaker activity. Phosphorylation has been reported to potently regulate the activity and gating properties of Cav 3.1 channels. However, systematic identification of phosphorylation sites (phosphosites) in Cav 3.1 channel has been poorly investigated. In this work, we analyzed rat Cav 3.1 protein expressed in HEK-293 cells by mass spectrometry, identified 30 phosphosites located at the cytoplasmic regions, and illustrated them as a Cav 3.1 phosphorylation map which includes the reported mouse Cav 3.1 phosphosites. Site-directed mutagenesis of the phosphosites to Ala residues and functional analysis of the phospho-silent Cav 3.1 mutants expressed in Xenopus oocytes showed that the phospho-silent mutation of the N-terminal Ser18 reduced its current amplitude with accelerated current kinetics and negatively shifted channel availability. Remarkably, the phospho-silent mutations of the C-terminal Ser residues (Ser1924, Ser2001, Ser2163, Ser2166, or Ser2189) greatly reduced their current amplitude without altering the voltage-dependent gating properties. In contrast, the phosphomimetic Asp mutations of Cav 3.1 on the N- and C-terminal Ser residues reversed the effects of the phospho-silent mutations. Collectively, these findings demonstrate that the multiple phosphosites of Cav 3.1 at the N- and C-terminal regions play crucial roles in the regulation of the channel activity and voltage-dependent gating properties.
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Affiliation(s)
- Sua Jeong
- Department of Life Science, Sogang University, Seoul, South Korea
| | - Ji Seon Shim
- Department of Physiology, Kyung-Hee University, Seoul, South Korea
| | - Seok Kyo Sin
- Department of Physiology, Kyung-Hee University, Seoul, South Korea
| | - Kang-Sik Park
- Department of Physiology, Kyung-Hee University, Seoul, South Korea
| | - Jung-Ha Lee
- Department of Life Science, Sogang University, Seoul, South Korea
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12
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Mustafá ER, Gambeta E, Stringer RN, Souza IA, Zamponi GW, Weiss N. Electrophysiological and computational analysis of Ca v3.2 channel variants associated with familial trigeminal neuralgia. Mol Brain 2022; 15:91. [PMID: 36397158 PMCID: PMC9670400 DOI: 10.1186/s13041-022-00978-9] [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: 10/12/2022] [Accepted: 11/02/2022] [Indexed: 11/18/2022] Open
Abstract
Trigeminal neuralgia (TN) is a rare form of chronic neuropathic pain characterized by spontaneous or elicited paroxysms of electric shock-like or stabbing pain in a region of the face. While most cases occur in a sporadic manner and are accompanied by intracranial vascular compression of the trigeminal nerve root, alteration of ion channels has emerged as a potential exacerbating factor. Recently, whole exome sequencing analysis of familial TN patients identified 19 rare variants in the gene CACNA1H encoding for Cav3.2T-type calcium channels. An initial analysis of 4 of these variants pointed to a pathogenic role. In this study, we assessed the electrophysiological properties of 13 additional TN-associated Cav3.2 variants expressed in tsA-201 cells. Our data indicate that 6 out of the 13 variants analyzed display alteration of their gating properties as evidenced by a hyperpolarizing shift of their voltage dependence of activation and/or inactivation resulting in an enhanced window current supported by Cav3.2 channels. An additional variant enhanced the recovery from inactivation. Simulation of neuronal electrical membrane potential using a computational model of reticular thalamic neuron suggests that TN-associated Cav3.2 variants could enhance neuronal excitability. Altogether, the present study adds to the notion that ion channel polymorphisms could contribute to the etiology of some cases of TN and further support a role for Cav3.2 channels.
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Affiliation(s)
- Emilio R. Mustafá
- grid.4491.80000 0004 1937 116XDepartment of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Eder Gambeta
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Robin N. Stringer
- grid.4491.80000 0004 1937 116XDepartment of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic ,grid.418095.10000 0001 1015 3316Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Ivana A. Souza
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Gerald W. Zamponi
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Norbert Weiss
- grid.4491.80000 0004 1937 116XDepartment of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
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13
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Ferron L, Zamponi GW. The road to the brain in Timothy syndrome is paved with enhanced CaV1.2 activation gating. J Gen Physiol 2022; 154:213558. [PMID: 36264243 PMCID: PMC9587385 DOI: 10.1085/jgp.202213272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Specific gating effects of Timothy syndrome CaV1.2 channel mutations determine cardiovascular versus nervous system deficits.
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Affiliation(s)
- Laurent Ferron
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
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14
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Eickhoff A, Tjaden J, Stahlke S, Vorgerd M, Theis V, Matschke V, Theiss C. Effects of progesterone on T-type-Ca 2+-channel expression in Purkinje cells. Neural Regen Res 2022; 17:2465-2471. [PMID: 35535898 PMCID: PMC9120685 DOI: 10.4103/1673-5374.339008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Plasticity of cerebellar Purkinje cells (PC) is influenced by progesterone via the classical progesterone receptors PR-A and PR-B by stimulating dendritogenesis, spinogenesis, and synaptogenesis in these cells. Dissociated PC cultures were used to analyze progesterone effects at a molecular level on the voltage-gated T-type-Ca2+-channels Cav3.1, Cav3.2, and Cav3.3 as they helped determine neuronal plasticity by regulating Ca2+-influx in neuronal cells. The results showed direct effects of progesterone on the mRNA expression of T-type-Ca2+-channels, as well as on the protein kinases A and C being involved in downstream signaling pathways that play an important role in neuronal plasticity. For the mRNA expression studies of T-type-Ca2+-channels and protein kinases of the signaling cascade, laser microdissection and purified PC cultures of different maturation stages were used. Immunohistochemical staining was also performed to characterize the localization of T-type-Ca2+-channels in PC. Experimental progesterone treatment was performed on the purified PC culture for 24 and 48 hours. Our results show that progesterone increases the expression of Cav3.1 and Cav3.3 and associated protein kinases A and C in PC at the mRNA level within 48 hours after treatment at latest. These effects extend the current knowledge of the function of progesterone in the central nervous system and provide an explanatory approach for its influence on neuronal plasticity.
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Affiliation(s)
- Annika Eickhoff
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Jonas Tjaden
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Sarah Stahlke
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Matthias Vorgerd
- Department of Neurology, Neuromuscular Center Ruhrgebiet, University Hospital Bergmannsheil, Ruhr-Universität Bochum, Bochum, Germany
| | - Verena Theis
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Veronika Matschke
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Carsten Theiss
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
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15
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Algahtani HA, Shirah BH, Samman A, Alhazmi A. Epilepsy and Hearing Loss in a Patient with a Rare Heterozygous Variant in the <i>CACNA1H</i> Gene. J Epilepsy Res 2022; 12:33-35. [PMID: 35910327 PMCID: PMC9289382 DOI: 10.14581/jer.22006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 01/22/2022] [Accepted: 02/09/2022] [Indexed: 11/03/2022] Open
Abstract
The calcium voltage-gated channel subunit alpha 1 H (<i>CACNA1H</i>) is a gene present in eukaryotic cells located on chromosome 16 that encodes the T-type calcium channels, which are important for calcium influx and depolarization of cells. Pathogenic variants in <i>CACNA1H</i> cause autosomal dominant susceptibility to idiopathic generalized epilepsy 6 (OMIM: 611942), which is a broad term that encompasses several common seizure phenotypes. In this article, we reported a Saudi female with a heterozygous variant in the <i>CACNA1H</i> gene (OMIM: 607904) who had epilepsy and hearing loss. This is the first case to report the association of epilepsy and hearing loss with a variant in <i>CACNA1H</i>. We believe that variant may be the reason for developing both epilepsy and sensorineural hearing loss. Further studies are needed to identify the role of <i>CACNA1H</i> in the physiology of the ear to allow for a better understanding of the effects of mutations. In children who present with early childhood hearing loss, genetic studies in highly selected cases including those with a strong family history of hearing loss and epilepsy may help detect a <i>CACNA1H</i> variant early and help with the early screening and diagnosis of other associated disorders including subclinical epilepsy.
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Affiliation(s)
- Hussein A. Algahtani
- Department of Medicine, King Abdulaziz Medical City, Jeddah, Saudi Arabia
- King Abdullah International Medical Research Center, Jeddah, Saudi Arabia
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Bader H. Shirah
- Department of Neuroscience, King Faisal Specialist Hospital & Research Centre, Jeddah, Saudi Arabia
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Abstract
Drug-resistant epilepsy is associated with poor health outcomes and increased economic burden. In the last three decades, various new antiseizure medications have been developed, but the proportion of people with drug-resistant epilepsy remains relatively unchanged. Developing strategies to address drug-resistant epilepsy is essential. Here, we define drug-resistant epilepsy and emphasize its relationship to the conceptualization of epilepsy as a symptom complex, delineate clinical risk factors, and characterize mechanisms based on current knowledge. We address the importance of ruling out pseudoresistance and consider the impact of nonadherence on determining whether an individual has drug-resistant epilepsy. We then review the principles of epilepsy drug therapy and briefly touch upon newly approved and experimental antiseizure medications.
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17
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Pong AW, Ross J, Tyrlikova I, Giermek AJ, Kohli MP, Khan YA, Salgado RD, Klein P. Epilepsy: Expert opinion on emerging drugs in phase 2/3 clinical trials. Expert Opin Emerg Drugs 2022; 27:75-90. [PMID: 35341431 DOI: 10.1080/14728214.2022.2059464] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Despite the existence of over 30 anti-seizure medications (ASM), including 20 over the last 30 years, a third of patients with epilepsy remain refractory to treatment, with no disease-modifying or preventive therapies until very recently. The development of new ASMs with new mechanisms of action is therefore critical. Recent clinical trials of new treatments have shifted focus from the traditional common epilepsies to rare, genetic epilepsies with known mechanistic targets for treatment and disease-specific animal models. AREAS COVERED ASMs in phase 2a/b and 3 clinical trials target cholesterol, serotonin, sigma-1 receptors, potassium channels and metabotrobic glutamate receptors. Neuroinflammation, protein misfolding, abnormal thalamocortical firing, and molecular deficiencies are among the targeted pathways. Clinically, the current phase 2a/b-3 agents hold promise for variety of epilepsy conditions, from developmental epileptic encephalopathies (Dravet Syndrome, Lennox-Gastaut syndrome, CDKL5 and PCDH19, Rett's Syndrome), Infantile Spasms, Tuberous Sclerosis as well as focal and idiopathic generalized epilepsies and acute rescue therapy for cluster seizures. EXPERT OPINION New delivery mechanisms increase potency and site-specificity of existing drugs. Novel mechanisms of action involve cholesterol degradation, mitochondrial pathways, anti-inflammation and neuro-regeneration. Earlier identification of genetic conditions through genetic testing will allow for earlier use of disease specific and disease-modifying therapies.
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Affiliation(s)
- Amanda W Pong
- Comprehensive Neurology Clinics of Bethesda, Mid-Atlantic Epilepsy and Sleep Center,Bethesda, MD, USA
| | - Jonathan Ross
- Comprehensive Neurology Clinics of Bethesda, Mid-Atlantic Epilepsy and Sleep Center,Bethesda, MD, USA
| | - Ivana Tyrlikova
- Comprehensive Neurology Clinics of Bethesda, Mid-Atlantic Epilepsy and Sleep Center,Bethesda, MD, USA
| | - Alexander J Giermek
- Comprehensive Neurology Clinics of Bethesda, Mid-Atlantic Epilepsy and Sleep Center,Bethesda, MD, USA
| | - Maya P Kohli
- Comprehensive Neurology Clinics of Bethesda, Mid-Atlantic Epilepsy and Sleep Center,Bethesda, MD, USA
| | - Yousef A Khan
- Comprehensive Neurology Clinics of Bethesda, Mid-Atlantic Epilepsy and Sleep Center,Bethesda, MD, USA
| | - Roger D Salgado
- Comprehensive Neurology Clinics of Bethesda, Mid-Atlantic Epilepsy and Sleep Center,Bethesda, MD, USA
| | - Pavel Klein
- Comprehensive Neurology Clinics of Bethesda, Mid-Atlantic Epilepsy and Sleep Center,Bethesda, MD, USA
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18
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Lanzetti S, Di Biase V. Small Molecules as Modulators of Voltage-Gated Calcium Channels in Neurological Disorders: State of the Art and Perspectives. Molecules 2022; 27:1312. [PMID: 35209100 PMCID: PMC8879281 DOI: 10.3390/molecules27041312] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 01/03/2023] Open
Abstract
Voltage-gated calcium channels (VGCCs) are widely expressed in the brain, heart and vessels, smooth and skeletal muscle, as well as in endocrine cells. VGCCs mediate gene transcription, synaptic and neuronal structural plasticity, muscle contraction, the release of hormones and neurotransmitters, and membrane excitability. Therefore, it is not surprising that VGCC dysfunction results in severe pathologies, such as cardiovascular conditions, neurological and psychiatric disorders, altered glycemic levels, and abnormal smooth muscle tone. The latest research findings and clinical evidence increasingly show the critical role played by VGCCs in autism spectrum disorders, Parkinson's disease, drug addiction, pain, and epilepsy. These findings outline the importance of developing selective calcium channel inhibitors and modulators to treat such prevailing conditions of the central nervous system. Several small molecules inhibiting calcium channels are currently used in clinical practice to successfully treat pain and cardiovascular conditions. However, the limited palette of molecules available and the emerging extent of VGCC pathophysiology require the development of additional drugs targeting these channels. Here, we provide an overview of the role of calcium channels in neurological disorders and discuss possible strategies to generate novel therapeutics.
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Affiliation(s)
| | - Valentina Di Biase
- Institute of Pharmacology, Department of Medical Statistics, Informatics and Health Economics, Medical University of Innsbruck, Peter-Mayr Strasse 1, A-6020 Innsbruck, Austria;
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Miller JP, Moldenhauer HJ, Keros S, Meredith AL. An emerging spectrum of variants and clinical features in KCNMA1-linked channelopathy. Channels (Austin) 2021; 15:447-464. [PMID: 34224328 PMCID: PMC8259716 DOI: 10.1080/19336950.2021.1938852] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 05/18/2021] [Accepted: 06/01/2021] [Indexed: 12/13/2022] Open
Abstract
KCNMA1-linked channelopathy is an emerging neurological disorder characterized by heterogeneous and overlapping combinations of movement disorder, seizure, developmental delay, and intellectual disability. KCNMA1 encodes the BK K+ channel, which contributes to both excitatory and inhibitory neuronal and muscle activity. Understanding the basis of the disorder is an important area of active investigation; however, the rare prevalence has hampered the development of large patient cohorts necessary to establish genotype-phenotype correlations. In this review, we summarize 37 KCNMA1 alleles from 69 patients currently defining the channelopathy and assess key diagnostic and clinical hallmarks. At present, 3 variants are classified as gain-of-function with respect to BK channel activity, 14 loss-of-function, 15 variants of uncertain significance, and putative benign/VUS. Symptoms associated with these variants were curated from patient-provided information and prior publications to define the spectrum of clinical phenotypes. In this newly expanded cohort, seizures showed no differential distribution between patients harboring GOF and LOF variants, while movement disorders segregated by mutation type. Paroxysmal non-kinesigenic dyskinesia was predominantly observed among patients with GOF alleles of the BK channel, although not exclusively so, while additional movement disorders were observed in patients with LOF variants. Neurodevelopmental and structural brain abnormalities were prevalent in patients with LOF mutations. In contrast to mutations, disease-associated KCNMA1 single nucleotide polymorphisms were not predominantly related to neurological phenotypes but covered a wider set of peripheral physiological functions. Together, this review provides additional evidence exploring the genetic and biochemical basis for KCNMA1-linked channelopathy and summarizes the clinical repository of patient symptoms across multiple types of KCNMA1 gene variants.
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Affiliation(s)
- Jacob P. Miller
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hans J. Moldenhauer
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sotirios Keros
- Department of Pediatrics, Weill Cornell Medical College, New York, NY, USA
| | - Andrea L. Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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Wei Z, Liu C, Wu Z, Cao M, Qiao X, Han T, Zhang Y, Liu Y, Deng Y. The prognosis of epilepsy patients with CACNA1H missense variants: A longitudinal cohort study. Seizure 2021; 91:52-59. [PMID: 34098317 DOI: 10.1016/j.seizure.2021.05.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVE CACNA1H is regarded as a gene conferring susceptibility to generalised epilepsy. However, the prognosis of epilepsy patients carrying the CACNA1H missense variants of uncertain significance (VUS) is unknown. A prospective cohort was generated to determine the deleterious effects of these variants and to check whether the presence of these variants affects the prognosis of epilepsy patients. METHOD This study was conducted at Xijing Hospital in Xian, China. All patients were followed up for at least 1 year. Previous reports were searched for previously reported variants. Ensembl database was searched for variants in the general population. Combined Annotation Dependent Depletion (CADD) was used to evaluate the deleterious effect of variants. Logistic regression and Cox regression were used for data analysis. RESULTS The study included 176 epilepsy patients with or without CACNA1H variants. In epilepsy patients with missense variants, we found 35 different variants, including 33 variants with uncertain significance and 2 likely benign variants. No significant difference was observed between the distribution of CADD scores of the variants from this cohort, of the general population, and of those found in previous reports. Among epilepsy patients with missense variants, the number of antiepileptic drugs (AEDs) administered to the patients, a first-degree family history of epilepsy, and possibly the presence of abnormalities in brain radiology findings were correlated with the poorer prognosis. Among the entire cohort, the type of epilepsy, number of AEDs administered, and presence of abnormalities in brain radiology findings were associated with the prognosis of these patients. The deleterious effect of CACNA1H missense variants or their presence was not related to the prognosis of epilepsy patients. CONCLUSION The results of our study suggest that CACNA1H variants are related to multiple epilepsy syndromes. However, there is no strong evidence of the correlation between CACNA1H missense variants and a certain type of epilepsy. In our study cohort, both the deleterious effects and the presence of CACNA1H variants were found to be unrelated to the prognosis of patients with epilepsy. These findings suggest that CACNA1H missense variants that are classified as VUS might not influence the outcome of epilepsy.
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Affiliation(s)
- Zihan Wei
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Chao Liu
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Zhenyu Wu
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, School of Basic Medicine, Fourth Military Medical University, Xi'an 710032, China
| | - Mi Cao
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Xiaozhi Qiao
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Tenghui Han
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Ying Zhang
- Department of Neurology, Xian International Medical Center, People's Republic of China
| | - Yonghong Liu
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Yanchun Deng
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China.
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Pulvirenti G, Caccamo M, Lo Bianco M, Mazzurco M, Praticò ER, Giallongo A, Gangi G, Zanghì A, Falsaperla R. Calcium Channels Genes and Their Epilepsy Phenotypes. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1728684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractCalcium (Ca2+) channel gene mutations play an important role in the pathogenesis of neurological episodic disorders like epilepsy. CACNA1A and CACNA1H genes are involved in the synthesis of calcium channels. Mutations in the α1A subunit of the P/Q type voltage-gated calcium channel gene (CACNA1A) located in 19p13.13, which encodes for the transmembrane pore-forming subunit of CAV2.1 voltage-dependent calcium channel, have been correlated to a large clinical spectrum of epilepsy such as idiopathic genetic epilepsy, early infantile epilepsy, and febrile seizures. Moreover, CACNA1A mutations have been demonstrated to be involved in spinocerebellar ataxia type 6, familiar hemiplegic migraine, episodic ataxia type 2, early-onset encephalopathy, and hemiconvulsion–hemiplegia epilepsy syndrome. This wide phenotype heterogeneity associated with CACNA1A mutations is correlated to different clinical and electrophysiological manifestations. CACNA1H gene, located in 16p13.3, encodes the α1H subunit of T-type calcium channel, expressing the transmembrane pore-forming subunit Cav3.2. Despite data still remain controversial, it has been identified as an important gene whose mutations seem strictly related to the pathogenesis of childhood absence epilepsy and other generalized epilepsies. The studied variants are mainly gain-of-function, hence responsible for an increase in neuronal susceptibility to seizures. CACNA1H mutations have also been associated with autism spectrum disorder and other behavior disorders. More recently, also amyotrophic lateral sclerosis has been related to CACNA1H alterations. The aim of this review, other than describe the CACNA1A and CACNA1H gene functions, is to identify mutations reported in literature and to analyze their possible correlations with specific epileptic disorders, purposing to guide an appropriate medical treatment recommendation.
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Affiliation(s)
- Giulio Pulvirenti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Martina Caccamo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | | | | | - Alessandro Giallongo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Gloria Gangi
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
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22
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Roebuck AJ, Greba Q, Smolyakova AM, Alaverdashvili M, Marks WN, Garai S, Baglot SL, Petrie G, Cain SM, Snutch TP, Thakur GA, Hill MN, Howland JG, Laprairie RB. Positive allosteric modulation of type 1 cannabinoid receptors reduces spike-and-wave discharges in Genetic Absence Epilepsy Rats from Strasbourg. Neuropharmacology 2021; 190:108553. [PMID: 33845076 DOI: 10.1016/j.neuropharm.2021.108553] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 01/30/2023]
Abstract
Childhood Absence Epilepsy (CAE) accounts for approximately 10% of all pediatric epilepsies. Current treatments for CAE are ineffective in approximately 1/3 of patients and can be associated with severe side effects such as hepatotoxicity. Certain cannabinoids, such as cannabidiol (CBD), have shown promise in the treatment of pediatric epilepsies. However, CBD remains limited or prohibited in many jurisdictions, and has not been shown to have efficacy in CAE. Modulation of the type 1 cannabinoid receptor (CB1R) may provide more desirable pharmacological treatments. Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model many aspects of CAE, including cortical spike and wave discharges (SWDs). We have recently demonstrated that Δ9-tetrahydrocannabinol (THC) increases SWDs in GAERS whereas CBD decreases these events. Here, we characterized aspects of the endocannabinoid system in brain areas relevant to seizures in GAERS and tested whether positive allosteric modulators (PAMs) of CB1R reduced SWDs. Both female and male GAERS had reduced (>50%) expression of CB1R and elevated levels of the endocannabinoid 2-AG in cortex compared to non-epileptic controls (NEC). We then administered the CB1R PAMs GAT211 and GAT229 to GAERS implanted with cortical electrodes. Systemic administration of GAT211 to male GAERS reduced SWDs by 40%. Systemic GAT229 administration reduced SWDs in female and male GAERS. Intracerebral infusion of GAT229 into the cortex of male GAERS reduced SWDs by >60% in a CB1R-dependent manner that was blocked by SR141716A. Together, these experiments identify altered endocannabinoid tone in GAERS and suggest that CB1R PAMs should be explored for treatment of absence seizures.
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Affiliation(s)
- Andrew J Roebuck
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada; School of Liberal Arts, Yukon University, Whitehorse, YT, Y1A 5K4, Canada
| | - Quentin Greba
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada
| | - Anna-Maria Smolyakova
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, S7N 2Z4, Canada
| | - Mariam Alaverdashvili
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, S7N 2Z4, Canada
| | - Wendie N Marks
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada
| | - Sumanta Garai
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, United States
| | - Samantha L Baglot
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Gavin Petrie
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Stuart M Cain
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Terrance P Snutch
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, United States
| | - Matthew N Hill
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - John G Howland
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada.
| | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, S7N 2Z4, Canada; Department of Pharmacology, College of Medicine, Dalhousie University, Halifax, NS, Canada, B3H 4R2.
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23
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Bladen C, Mirlohi S, Santiago M, Longworth M, Kassiou M, Banister S, Connor M. Modulation of human T-type calcium channels by synthetic cannabinoid receptor agonists in vitro. Neuropharmacology 2021; 187:108478. [PMID: 33600843 DOI: 10.1016/j.neuropharm.2021.108478] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/07/2021] [Accepted: 01/26/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND AND PURPOSE Consumption of Synthetic Cannabinoid Receptor agonists (SCRAs) is associated with severe adverse reactions including seizures, arrhythmias and death, but the molecular mechanisms surrounding SCRA toxicity are not yet established. These disease-like symptoms are also synonymous with altered T-type calcium channel activity which controls rhythmicity in the heart and brain. This study examined whether SCRAs alter T-type activity and whether this represents a possible mechanism of toxicity. EXPERIMENTAL APPROACH Fluorescence-based and electrophysiology assays were used to screen 16 structurally related synthetic cannabinoids for their ability to inhibit human T-type calcium channels expressed in HEK293 cells. The most potent compounds were then further examined using patch clamp electrophysiology. KEY RESULTS MDMB-CHMICA and AMB-CHMINACA potently blocked Cav3.2 with IC50 values of 1.5 and 0.74 μM respectively. Current inhibition increased from 47 to 80% and 45-87% respectively when the channel was in slow-inactivated state. Both SCRAs had little effect on steady state inactivation, however MDMB-CHMICA significantly shifted the half activation potential by -7mV. Neither drug produced frequency dependent block, in contrast to the phytocannabinoid Δ9-THC. CONCLUSIONS AND IMPLICATIONS SCRAs are potent agonists of CB1 receptors and can be extremely toxic, but observed toxicity also resembles symptoms associated with altered Cav3.2 activity. Many SCRAs tested were potent modulators of Cav3.2, raising the possibility that SC toxicity may be due in part to Cav3.2 modulation. This potent T-type channel modulation suggests the possibility of SCRAs as a new drug class with potential to treat diseases associated with altered T-type channel activity. This article is part of the special issue on 'Cannabinoids'.
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Affiliation(s)
- Chris Bladen
- Biomedical Sciences, Macquarie University, Sydney, NSW, Australia.
| | - Somayeh Mirlohi
- Biomedical Sciences, Macquarie University, Sydney, NSW, Australia
| | - Marina Santiago
- Biomedical Sciences, Macquarie University, Sydney, NSW, Australia
| | | | - Michael Kassiou
- School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia
| | - Sam Banister
- School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia; The Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, Sydney, NSW, 2006, Australia
| | - Mark Connor
- Biomedical Sciences, Macquarie University, Sydney, NSW, Australia
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24
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Huang M, Nibbeling EAR, Lagrand TJ, Souza IA, Groen JL, Gandini MA, Zhang FX, Koelman JHTM, Adir N, Sinke RJ, Zamponi GW, Tijssen MAJ, Verbeek DS. Rare functional missense variants in CACNA1H: What can we learn from Writer's cramp? Mol Brain 2021; 14:18. [PMID: 33478561 PMCID: PMC7819179 DOI: 10.1186/s13041-021-00736-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/13/2021] [Indexed: 11/10/2022] Open
Abstract
Writer's cramp (WC) is a task-specific focal dystonia that occurs selectively in the hand and arm during writing. Previous studies have shown a role for genetics in the pathology of task-specific focal dystonia. However, to date, no causal gene has been reported for task-specific focal dystonia, including WC. In this study, we investigated the genetic background of a large Dutch family with autosomal dominant‒inherited WC that was negative for mutations in known dystonia genes. Whole exome sequencing identified 4 rare variants of unknown significance that segregated in the family. One candidate gene was selected for follow-up, Calcium Voltage-Gated Channel Subunit Alpha1 H, CACNA1H, due to its links with the known dystonia gene Potassium Channel Tetramerization Domain Containing 17, KCTD17, and with paroxysmal movement disorders. Targeted resequencing of CACNA1H in 82 WC cases identified another rare, putative damaging variant in a familial WC case that did not segregate. Using structural modelling and functional studies in vitro, we show that both the segregating p.Arg481Cys variant and the non-segregating p.Glu1881Lys variant very likely cause structural changes to the Cav3.2 protein and lead to similar gains of function, as seen in an accelerated recovery from inactivation. Both mutant channels are thus available for re-activation earlier, which may lead to an increase in intracellular calcium and increased neuronal excitability. Overall, we conclude that rare functional variants in CACNA1H need to be interpreted very carefully, and additional studies are needed to prove that the p.Arg481Cys variant is the cause of WC in the large Dutch family.
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Affiliation(s)
- Miaozhen Huang
- Department of Genetics, University Medical Center Groningen, University of Groningen, P.O. box 30 001, 9700 RB, Groningen, The Netherlands
| | - Esther A R Nibbeling
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Tjerk J Lagrand
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ivana A Souza
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Justus L Groen
- Department of Neurosurgery, Leiden University Medical Centre, Leiden, The Netherlands
| | - Maria A Gandini
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Fang-Xiong Zhang
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Johannes H T M Koelman
- Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Noam Adir
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion, Israel
| | - Richard J Sinke
- Department of Genetics, University Medical Center Groningen, University of Groningen, P.O. box 30 001, 9700 RB, Groningen, The Netherlands
| | - Gerald W Zamponi
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Marina A J Tijssen
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Dineke S Verbeek
- Department of Genetics, University Medical Center Groningen, University of Groningen, P.O. box 30 001, 9700 RB, Groningen, The Netherlands.
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25
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Myers KA, Bennett MF, Grinton BE, Dabscheck G, Chan EK, Bello-Espinosa LE, Sadleir LG, D'Alfonso S, Schneider AL, Damiano JA, Hildebrand MS, Bahlo M, Berkovic SF, Buchhalter J, Scheffer IE. Contribution of rare genetic variants to drug response in absence epilepsy. Epilepsy Res 2021; 170:106537. [PMID: 33421703 DOI: 10.1016/j.eplepsyres.2020.106537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 01/02/2023]
Abstract
OBJECTIVE We investigated the possible significance of rare genetic variants to response to valproic acid (VPA) and ethosuximide (ETX) in patients with absence epilepsy. Our primary hypothesis was that rare CACNA1H variants are more frequent in ETX-non-responsive patients compared to ETX-responsive. Our secondary hypothesis was that rare variants in GABA-receptor genes are more frequent in VPA-non-responsive patients compared to VPA-responsive. METHODS We recruited patients with absence epilepsy treated with both VPA and ETX, and performed whole exome sequencing in order to investigate the potential role of rare variants in CACNA1H, other voltage-gated calcium channel (VGCC) genes, or GABA-receptor genes in predicting response to ETX or VPA. RESULTS Sixty-two patients were included; 12 were ETX-responsive, 14 VPA-responsive, and 36 did not have a clear positive response to either medication. We did not find significant enrichment inCACNA1H rare variants in ETX-responsive patients (odds ratio 3.43; 0.43-27.65; p = 0.20), nor was there enrichment for other VGCC genes. No significant enrichment of GABA-receptor gene rare variants was seen for VPA-non-responsive patients versus VPA-responsive. We found enrichment of rare GABA-receptor variants in our absence cohort compared to controls (odds ratio 3.82; 1.68-8.69). There was no difference in frequency of CACNA1H rs61734410 and CACNA1I rs3747178 polymorphisms between ETX-responsive and ETX-non-responsive groups; these polymorphisms have previously been reported to predict lack of response to ETX in absence epilepsy. SIGNIFICANCE We conclude that if CACNA1H rare variants predict lack of response to ETX, a larger sample is necessary to test this with sufficient power. Increased GABA-receptor gene rare variant frequency in absence epilepsy patients who fail initial anti-seizure therapy suggests subtle GABA receptor dysfunction may contribute to the underlying pathophysiology.
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Affiliation(s)
- Kenneth A Myers
- Department of Pediatrics, Division of Child Neurology, Montreal Children's Hospital, McGill University Health Centre, 1001 Décarie Blvd, Montreal, PQ, H4A 3J1, Canada; Department of Neurology & Neurosurgery, Montreal Children's Hospital, McGill University Health Centre, 1001 Décarie Blvd, Montreal, PQ, H4A 3J1, Canada; Research Institute of the McGill University Health Center, 1001 Décarie Blvd, Montreal, PQ, H4A 3J1, Canada; Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, 245 Burgundy St, Heidelberg, VIC, 3084, Australia.
| | - Mark F Bennett
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, 245 Burgundy St, Heidelberg, VIC, 3084, Australia; Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, 1G, Royal Parade, Parkville, VIC, 3052, Australia; Department of Medical Biology, The University of Melbourne, 1G, Royal Parade, Parkville, VIC, 3052, Australia
| | - Bronwyn E Grinton
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, 245 Burgundy St, Heidelberg, VIC, 3084, Australia
| | - Gabriel Dabscheck
- Department of Neurology, Royal Children's Hospital, The University of Melbourne, 50 Flemington Rd, Parkville, VIC, 3052, Australia
| | - Eunice K Chan
- Department of Neurology, Royal Children's Hospital, The University of Melbourne, 50 Flemington Rd, Parkville, VIC, 3052, Australia
| | - Luis E Bello-Espinosa
- Division of Pediatric Neurology, Department of Pediatrics, Alberta Children's Hospital, Cumming School of Medicine, University of Calgary, 28 Oki Dr NW, Calgary, AB, T3B 6A8, Canada
| | - Lynette G Sadleir
- Department of Paediatrics and Child Health, University of Otago, Wellington, 23 Mein Street, Newtown, Wellington, 6021, New Zealand
| | - Sabrina D'Alfonso
- Division of Pediatric Neurology, Department of Pediatrics, Alberta Children's Hospital, Cumming School of Medicine, University of Calgary, 28 Oki Dr NW, Calgary, AB, T3B 6A8, Canada
| | - Amy L Schneider
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, 245 Burgundy St, Heidelberg, VIC, 3084, Australia
| | - John A Damiano
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, 245 Burgundy St, Heidelberg, VIC, 3084, Australia
| | - Michael S Hildebrand
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, 245 Burgundy St, Heidelberg, VIC, 3084, Australia; Murdoch Children's Research Institute, Royal Children's Hospital, 50 Flemington Rd, Parkville, VIC, 3052, Australia
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, 1G, Royal Parade, Parkville, VIC, 3052, Australia; Department of Medical Biology, The University of Melbourne, 1G, Royal Parade, Parkville, VIC, 3052, Australia
| | - Samuel F Berkovic
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, 245 Burgundy St, Heidelberg, VIC, 3084, Australia
| | - Jeffrey Buchhalter
- Division of Pediatric Neurology, Department of Pediatrics, Alberta Children's Hospital, Cumming School of Medicine, University of Calgary, 28 Oki Dr NW, Calgary, AB, T3B 6A8, Canada
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, 245 Burgundy St, Heidelberg, VIC, 3084, Australia; Department of Neurology, Royal Children's Hospital, The University of Melbourne, 50 Flemington Rd, Parkville, VIC, 3052, Australia; Murdoch Children's Research Institute, Royal Children's Hospital, 50 Flemington Rd, Parkville, VIC, 3052, Australia; Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia
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26
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Roebuck AJ, Greba Q, Onofrychuk TJ, McElroy DL, Sandini TM, Zagzoog A, Simone J, Cain SM, Snutch TP, Laprairie RB, Howland JG. Dissociable changes in spike and wave discharges following exposure to injected cannabinoids and smoked cannabis in Genetic Absence Epilepsy Rats from Strasbourg. Eur J Neurosci 2020; 55:1063-1078. [PMID: 33370468 DOI: 10.1111/ejn.15096] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/14/2020] [Accepted: 12/22/2020] [Indexed: 12/11/2022]
Abstract
There is significant interest in the use of cannabinoids for the treatment of many epilepsies including absence epilepsy (AE). Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model many aspects of AE including the presence of spike-and-wave discharges (SWDs) on electroencephalogram (EEG) and behavioral comorbidities, such as elevated anxiety. However, the effects of cannabis plant-based phytocannabinoids have not been tested in GAERS. Therefore, we investigated how SWDs in GAERS are altered by the two most common phytocannabinoids, Δ9 -tetrahydrocannabinol (THC) and cannabidiol (CBD), and exposure to smoke from two different chemovars of cannabis. Animals were implanted with bipolar electrodes in the somatosensory cortex and EEGs were recorded for 2 hr. Injected THC (1-10 mg/kg, i.p.) dose-dependently increased SWDs to over 200% of baseline. In contrast, CBD (30-100 mg/kg, i.p.) produced a ~50% reduction in SWDs. Exposure to smoke from a commercially available chemovar of high-THC cannabis (Mohawk, Aphria Inc.) increased SWDs whereas a low-THC/high-CBD chemovar of cannabis (Treasure Island, Aphria Inc.) did not significantly affect SWDs in GAERS. Pre-treatment with a CB1R antagonist (SR141716A) did not prevent the high-THC cannabis smoke from increasing SWDs, suggesting that the THC-mediated increase may not be CB1R-dependent. Plasma concentrations of THC and CBD were similar to previously reported values following injection and smoke exposure. Compared to injected CBD, it appears Treasure Island did not increase plasma levels sufficiently to observe an anti-epileptic effect. Together these experiments provide initial evidence that acute phytocannabinoid administration exerts the biphasic modulation of SWDs and may differentially impact patients with AE.
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Affiliation(s)
- Andrew J Roebuck
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada.,School of Liberal Arts, Yukon University, Whitehorse, YT, Canada
| | - Quentin Greba
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Timothy J Onofrychuk
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Dan L McElroy
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Thaísa M Sandini
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Jonathan Simone
- Department of Biological Sciences, Centre for Neuroscience, Brock University, St. Catharines, ON, Canada
| | - Stuart M Cain
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Colombia, Vancouver, BC, Canada
| | - Terrance P Snutch
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Colombia, Vancouver, BC, Canada
| | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Pharmacology, College of Medicine, Dalhousie University, Halifax, NS, Canada
| | - John G Howland
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
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27
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Juvale IIA, Che Has AT. Possible interplay between the theories of pharmacoresistant epilepsy. Eur J Neurosci 2020; 53:1998-2026. [PMID: 33306252 DOI: 10.1111/ejn.15079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/22/2020] [Accepted: 12/04/2020] [Indexed: 02/06/2023]
Abstract
Epilepsy is one of the oldest known neurological disorders and is characterized by recurrent seizure activity. It has a high incidence rate, affecting a broad demographic in both developed and developing countries. Comorbid conditions are frequent in patients with epilepsy and have detrimental effects on their quality of life. Current management options for epilepsy include the use of anti-epileptic drugs, surgery, or a ketogenic diet. However, more than 30% of patients diagnosed with epilepsy exhibit drug resistance to anti-epileptic drugs. Further, surgery and ketogenic diets do little to alleviate the symptoms of patients with pharmacoresistant epilepsy. Thus, there is an urgent need to understand the underlying mechanisms of pharmacoresistant epilepsy to design newer and more effective anti-epileptic drugs. Several theories of pharmacoresistant epilepsy have been suggested over the years, the most common being the gene variant hypothesis, network hypothesis, multidrug transporter hypothesis, and target hypothesis. In our review, we discuss the main theories of pharmacoresistant epilepsy and highlight a possible interconnection between their mechanisms that could lead to the development of novel therapies for pharmacoresistant epilepsy.
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Affiliation(s)
- Iman Imtiyaz Ahmed Juvale
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Ahmad Tarmizi Che Has
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
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28
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Genomic analysis of 21 patients with corneal neuralgia after refractive surgery. Pain Rep 2020; 5:e826. [PMID: 32766464 PMCID: PMC7390595 DOI: 10.1097/pr9.0000000000000826] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/30/2020] [Accepted: 05/13/2020] [Indexed: 12/19/2022] Open
Abstract
Background Refractive surgery, specifically laser-assisted in situ keratomileusis and photorefractive keratectomy, are widely applied procedures to treat myopia, hyperopia, and astigmatism. After surgery, a subgroup of cases suffers from persistent and intractable pain of obscure etiology, thought to be neuropathic. We aimed to investigate the contribution of genomic factors in the pathogenesis of these patients with corneal neuralgia. Methods We enrolled 21 cases (6 males and 15 females) from 20 unrelated families, who reported persistent pain (>3 months), after refractive surgery (20 laser-assisted in situ keratomileusis and 1 photorefractive keratectomy patients). Whole-exome sequencing and gene-based association test were performed. Results Whole-exome sequencing demonstrated low-frequency variants (allele frequency < 0.05) in electrogenisome-related ion channels and cornea-expressed collagens, most frequently in SCN10A (5 cases), SCN9A (4 cases), TRPV1 (4 cases), CACNA1H and CACNA2D2 (5 cases each), COL5A1 (6 cases), COL6A3 (5 cases), and COL4A2 (4 cases). Two variants, p.K655R of SCN9A and p.Q85R of TRPV1, were previously characterized as gain-of-function. Gene-based association test assessing "damaging" missense variants against gnomAD exome database (non-Finnish European or global), identified a gene, SLC9A3R1, with statistically significant effect (odds ratio = 17.09 or 17.04; Bonferroni-corrected P-value < 0.05). Conclusion These findings in a small patient cohort did not identify a common gene/variant among most of these cases, as found in other disorders, for example small-fiber neuropathy. Further studies of these candidate genes/variants might enhance understanding of the role of genetic factors in the pathogenesis of corneal neuralgia.
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29
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Lory P, Nicole S, Monteil A. Neuronal Cav3 channelopathies: recent progress and perspectives. Pflugers Arch 2020; 472:831-844. [PMID: 32638069 PMCID: PMC7351805 DOI: 10.1007/s00424-020-02429-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/08/2020] [Accepted: 06/26/2020] [Indexed: 12/22/2022]
Abstract
T-type, low-voltage activated, calcium channels, now designated Cav3 channels, are involved in a wide variety of physiological functions, especially in nervous systems. Their unique electrophysiological properties allow them to finely regulate neuronal excitability and to contribute to sensory processing, sleep, and hormone and neurotransmitter release. In the last two decades, genetic studies, including exploration of knock-out mouse models, have greatly contributed to elucidate the role of Cav3 channels in normal physiology, their regulation, and their implication in diseases. Mutations in genes encoding Cav3 channels (CACNA1G, CACNA1H, and CACNA1I) have been linked to a variety of neurodevelopmental, neurological, and psychiatric diseases designated here as neuronal Cav3 channelopathies. In this review, we describe and discuss the clinical findings and supporting in vitro and in vivo studies of the mutant channels, with a focus on de novo, gain-of-function missense mutations recently discovered in CACNA1G and CACNA1H. Overall, the studies of the Cav3 channelopathies help deciphering the pathogenic mechanisms of corresponding diseases and better delineate the properties and physiological roles Cav3 channels.
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Affiliation(s)
- Philippe Lory
- Institut de Génomique Fonctionnelle, CNRS, INSERM, University Montpellier, 141, rue de la Cardonille, 34094, Montpellier, France. .,LabEx 'Ion Channel Science and Therapeutics' (ICST), Montpellier, France.
| | - Sophie Nicole
- Institut de Génomique Fonctionnelle, CNRS, INSERM, University Montpellier, 141, rue de la Cardonille, 34094, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics' (ICST), Montpellier, France
| | - Arnaud Monteil
- Institut de Génomique Fonctionnelle, CNRS, INSERM, University Montpellier, 141, rue de la Cardonille, 34094, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics' (ICST), Montpellier, France
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30
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Chow CY, Absalom N, Biggs K, King GF, Ma L. Venom-derived modulators of epilepsy-related ion channels. Biochem Pharmacol 2020; 181:114043. [PMID: 32445870 DOI: 10.1016/j.bcp.2020.114043] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/18/2020] [Indexed: 12/18/2022]
Abstract
Epilepsy is characterised by spontaneous recurrent seizures that are caused by an imbalance between neuronal excitability and inhibition. Since ion channels play fundamental roles in the generation and propagation of action potentials as well as neurotransmitter release at a subset of excitatory and inhibitory synapses, their dysfunction has been linked to a wide variety of epilepsies. Indeed, these unique proteins are the major biological targets for antiepileptic drugs. Selective targeting of a specific ion channel subtype remains challenging for small molecules, due to the high level of homology among members of the same channel family. As a consequence, there is a growing trend to target ion channels with biologics. Venoms are the best known natural source of ion channel modulators, and venom peptides are increasingly recognised as potential therapeutics due to their high selectivity and potency gained through millions of years of evolutionary selection pressure. Here we describe the major ion channel families involved in the pathogenesis of various types of epilepsy, including voltage-gated Na+, K+, Ca2+ channels, Cys-loop receptors, ionotropic glutamate receptors and P2X receptors, and currently available venom-derived peptides that target these channel proteins. Although only a small number of venom peptides have successfully progressed to the clinic, there is reason to be optimistic about their development as antiepileptic drugs, notwithstanding the challenges associated with development of any class of peptide drug.
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Affiliation(s)
- Chun Yuen Chow
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nathan Absalom
- Brain and Mind Centre, School of Pharmacy, Faculty of Health and Medicine, The University of Sydney, Sydney, NSW 2050, Australia
| | - Kimberley Biggs
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Linlin Ma
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia.
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31
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Calhoun JD, Huffman AM, Bellinski I, Kinsley L, Bachman E, Gerard E, Kearney JA, Carvill GL. CACNA1H variants are not a cause of monogenic epilepsy. Hum Mutat 2020; 41:1138-1144. [PMID: 32227660 DOI: 10.1002/humu.24017] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/06/2020] [Accepted: 03/17/2020] [Indexed: 12/18/2022]
Abstract
CACNA1H genetic variants were originally reported in a childhood absence epilepsy cohort. Subsequently, genetic testing for CACNA1H became available and is currently offered by commercial laboratories. However, the current status of CACNA1H as a monogenic cause of epilepsy is controversial, highlighted by ClinGen's recent reclassification of CACNA1H as disputed. We analyzed published CACNA1H variants and those reported in ClinVar and found none would be classified as pathogenic or likely pathogenic per the American College of Medical Genetics classification criteria. Moreover, Cacna1h did not modify survival in a Dravet Syndrome mouse model. We observed a mild increase in susceptibility to hyperthermia-induced seizures in mice with reduced Cacna1h expression. Overall, we conclude that there is limited evidence that CACNA1H is a monogenic cause of epilepsy in humans and that this gene should be removed from commercial genetic testing panels to reduce the burden of variants of uncertain significance for healthcare providers, families and patients with epilepsy.
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Affiliation(s)
- Jeffrey D Calhoun
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Alexandra M Huffman
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Irena Bellinski
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Lisa Kinsley
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Elizabeth Bachman
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Elizabeth Gerard
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Jennifer A Kearney
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Gemma L Carvill
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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32
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Abstract
Primary aldosteronism (PA) is the most common form of secondary hypertension affecting 5%-10% of patients with arterial hypertension. In PA, high blood pressure is associated with high aldosterone and low renin levels, and often hypokalemia. In a majority of cases, autonomous aldosterone production by the adrenal gland is caused by an aldosterone producing adenoma (APA) or bilateral adrenal hyperplasia (BAH). During the last ten years, a better knowledge of the pathophysiology of PA came from the discovery of somatic and germline mutations in different genes in both sporadic and familial forms of the disease. Those genes code for ion channels and pumps, as well as proteins involved in adrenal cortex development and function. Targeted next generation sequencing following immunohistochemistry guided detection of aldosterone synthase expression allows detection of somatic mutations in up to 90% of APA, while whole exome sequencing has discovered the genetic causes of four different familial forms of PA. The identification, in BAH, of somatic mutations in aldosterone producing cell clusters open new perspectives in our understanding of the bilateral form of the disease and the development of new therapeutic approaches.
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Affiliation(s)
| | | | - Maria-Christina Zennaro
- Université de Paris, PARCC, INSERM, Paris, France; Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France
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33
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Cárdenas-Rodríguez N, Carmona-Aparicio L, Pérez-Lozano DL, Ortega-Cuellar D, Gómez-Manzo S, Ignacio-Mejía I. Genetic variations associated with pharmacoresistant epilepsy (Review). Mol Med Rep 2020; 21:1685-1701. [PMID: 32319641 PMCID: PMC7057824 DOI: 10.3892/mmr.2020.10999] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is a common, serious neurological disorder worldwide. Although this disease can be successfully treated in most cases, not all patients respond favorably to medical treatments, which can lead to pharmacoresistant epilepsy. Drug-resistant epilepsy can be caused by a number of mechanisms that may involve environmental and genetic factors, as well as disease- and drug-related factors. In recent years, numerous studies have demonstrated that genetic variation is involved in the drug resistance of epilepsy, especially genetic variations found in drug resistance-related genes, including the voltage-dependent sodium and potassium channels genes, and the metabolizer of endogenous and xenobiotic substances genes. The present review aimed to highlight the genetic variants that are involved in the regulation of drug resistance in epilepsy; a comprehensive understanding of the role of genetic variation in drug resistance will help us develop improved strategies to regulate drug resistance efficiently and determine the pathophysiological processes that underlie this common human neurological disease.
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Affiliation(s)
- Noemí Cárdenas-Rodríguez
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Liliana Carmona-Aparicio
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Diana L Pérez-Lozano
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Daniel Ortega-Cuellar
- Laboratory of Experimental Nutrition, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Saúl Gómez-Manzo
- Laboratory of Genetic Biochemistry, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Iván Ignacio-Mejía
- Laboratory of Translational Medicine, Military School of Health Graduates, Lomas de Sotelo, Militar, Mexico City 11200, Mexico
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34
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Weiss N, Zamponi GW. Genetic T-type calcium channelopathies. J Med Genet 2020; 57:1-10. [PMID: 31217264 PMCID: PMC6929700 DOI: 10.1136/jmedgenet-2019-106163] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/02/2019] [Accepted: 05/18/2019] [Indexed: 12/13/2022]
Abstract
T-type channels are low-voltage-activated calcium channels that contribute to a variety of cellular and physiological functions, including neuronal excitability, hormone and neurotransmitter release as well as developmental aspects. Several human conditions including epilepsy, autism spectrum disorders, schizophrenia, motor neuron disorders and aldosteronism have been traced to variations in genes encoding T-type channels. In this short review, we present the genetics of T-type channels with an emphasis on structure-function relationships and associated channelopathies.
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Affiliation(s)
- Norbert Weiss
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Praha, Czech Republic
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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35
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Miao QL, Herlitze S, Mark MD, Noebels JL. Adult loss of Cacna1a in mice recapitulates childhood absence epilepsy by distinct thalamic bursting mechanisms. Brain 2020; 143:161-174. [PMID: 31800012 PMCID: PMC6935748 DOI: 10.1093/brain/awz365] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/09/2019] [Accepted: 09/29/2019] [Indexed: 12/15/2022] Open
Abstract
Inborn errors of CACNA1A-encoded P/Q-type calcium channels impair synaptic transmission, producing early and lifelong neurological deficits, including childhood absence epilepsy, ataxia and dystonia. Whether these impairments owe their pathologies to defective channel function during the critical period for thalamic network stabilization in immature brain remains unclear. Here we show that mice with tamoxifen-induced adult-onset ablation of P/Q channel alpha subunit (iKOp/q) display identical patterns of dysfunction, replicating the inborn loss-of-function phenotypes and, therefore demonstrate that these neurological defects do not rely upon developmental abnormality. Unexpectedly, unlike the inborn model, the adult-onset pattern of excitability changes believed to be pathogenic within the thalamic network is non-canonical. Specifically, adult ablation of P/Q channels does not promote Cacna1g-mediated burst firing or T-type calcium current (IT) in the thalamocortical relay neurons; however, burst firing in thalamocortical relay neurons remains essential as iKOp/q mice generated on a Cacna1g deleted background show substantially diminished seizure generation. Moreover, in thalamic reticular nucleus neurons, burst firing is impaired accompanied by attenuated IT. Interestingly, inborn deletion of thalamic reticular nucleus-enriched, human childhood absence epilepsy-linked gene Cacna1h in iKOp/q mice reduces thalamic reticular nucleus burst firing and promotes rather than reduces seizure, indicating an epileptogenic role for loss-of-function Cacna1h gene variants reported in human childhood absence epilepsy cases. Together, our results demonstrate that P/Q channels remain critical for maintaining normal thalamocortical oscillations and motor control in the adult brain, and suggest that the developmental plasticity of membrane currents regulating pathological rhythmicity is both degenerate and age-dependent.
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Affiliation(s)
- Qing-Long Miao
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston TX, USA
| | - Stefan Herlitze
- Department of Zoology and Neurobiology, Ruhr University of Bochum, Bochum, Germany
| | - Melanie D Mark
- Department of Zoology and Neurobiology, Ruhr University of Bochum, Bochum, Germany
| | - Jeffrey L Noebels
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX, USA
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36
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Zhao Y, Huang G, Wu Q, Wu K, Li R, Lei J, Pan X, Yan N. Cryo-EM structures of apo and antagonist-bound human Ca v3.1. Nature 2019; 576:492-497. [PMID: 31766050 DOI: 10.1038/s41586-019-1801-3] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 11/01/2019] [Indexed: 01/02/2023]
Abstract
Among the ten subtypes of mammalian voltage-gated calcium (Cav) channels, Cav3.1-Cav3.3 constitute the T-type, or the low-voltage-activated, subfamily, the abnormal activities of which are associated with epilepsy, psychiatric disorders and pain1-5. Here we report the cryo-electron microscopy structures of human Cav3.1 alone and in complex with a highly Cav3-selective blocker, Z9446,7, at resolutions of 3.3 Å and 3.1 Å, respectively. The arch-shaped Z944 molecule reclines in the central cavity of the pore domain, with the wide end inserting into the fenestration on the interface between repeats II and III, and the narrow end hanging above the intracellular gate like a plug. The structures provide the framework for comparative investigation of the distinct channel properties of different Cav subfamilies.
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Affiliation(s)
- Yanyu Zhao
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Gaoxingyu Huang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qiurong Wu
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Kun Wu
- Medical Research Center, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Ruiqi Li
- Medical Research Center, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Jianlin Lei
- Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiaojing Pan
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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37
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Souza IA, Gandini MA, Zhang FX, Mitchell WG, Matsumoto J, Lerner J, Pierson TM, Zamponi GW. Pathogenic Cav3.2 channel mutation in a child with primary generalized epilepsy. Mol Brain 2019; 12:86. [PMID: 31651342 PMCID: PMC6814130 DOI: 10.1186/s13041-019-0509-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/02/2019] [Indexed: 12/31/2022] Open
Abstract
Two paternally-inherited missense variants in CACNA1H were identified and characterized in a 6-year-old child with generalized epilepsy. Febrile and unprovoked seizures were present in this child. Both variants were expressed in cis or isolation using human recombinant Cav3.2 calcium channels in tsA-201 cells. Whole-cell patch-clamp recordings indicated that one variant (c.3844C > T; p.R1282W) caused a significant increase in current density consistent with a pathogenic gain-of-function phenotype; while the other cis-related variant (c.5294C > T; p.A1765V) had a benign profile.
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Affiliation(s)
- Ivana A Souza
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, T2N 4N1, Canada
| | - Maria A Gandini
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, T2N 4N1, Canada
| | - Fang-Xiong Zhang
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, T2N 4N1, Canada
| | - Wendy G Mitchell
- Neurology Division, Children's Hospital Los Angeles & Department of Neurology, Keck School of Medicine of University of Southern California, Los Angeles, USA
| | - Joyce Matsumoto
- Department of Pediatrics, Division of Pediatric Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Jason Lerner
- Department of Pediatrics, Division of Pediatric Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Tyler Mark Pierson
- Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, T2N 4N1, Canada.
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38
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Mustafá ER, Cordisco Gonzalez S, Raingo J. Ghrelin Selectively Inhibits CaV3.3 Subtype of Low-Voltage-Gated Calcium Channels. Mol Neurobiol 2019; 57:722-735. [DOI: 10.1007/s12035-019-01738-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 08/16/2019] [Indexed: 01/01/2023]
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39
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Tangwiriyasakul C, Perani S, Centeno M, Yaakub SN, Abela E, Carmichael DW, Richardson MP. Dynamic brain network states in human generalized spike-wave discharges. Brain 2019; 141:2981-2994. [PMID: 30169608 PMCID: PMC6158757 DOI: 10.1093/brain/awy223] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 07/15/2018] [Indexed: 12/21/2022] Open
Abstract
Generalized spike-wave discharges in idiopathic generalized epilepsy are conventionally assumed to have abrupt onset and offset. However, in rodent models, discharges emerge during a dynamic evolution of brain network states, extending several seconds before and after the discharge. In human idiopathic generalized epilepsy, simultaneous EEG and functional MRI shows cortical regions may be active before discharges, and network connectivity around discharges may not be normal. Here, in human idiopathic generalized epilepsy, we investigated whether generalized spike-wave discharges emerge during a dynamic evolution of brain network states. Using EEG-functional MRI, we studied 43 patients and 34 healthy control subjects. We obtained 95 discharges from 20 patients. We compared data from patients with discharges with data from patients without discharges and healthy controls. Changes in MRI (blood oxygenation level-dependent) signal amplitude in discharge epochs were observed only at and after EEG onset, involving a sequence of parietal and frontal cortical regions then thalamus (P < 0.01, across all regions and measurement time points). Examining MRI signal phase synchrony as a measure of functional connectivity between each pair of 90 brain regions, we found significant connections (P < 0.01, across all connections and measurement time points) involving frontal, parietal and occipital cortex during discharges, and for 20 s after EEG offset. This network prominent during discharges showed significantly low synchrony (below 99% confidence interval for synchrony in this network in non-discharge epochs in patients) from 16 s to 10 s before discharges, then ramped up steeply to a significantly high level of synchrony 2 s before discharge onset. Significant connections were seen in a sensorimotor network in the minute before discharge onset. This network also showed elevated synchrony in patients without discharges compared to healthy controls (P = 0.004). During 6 s prior to discharges, additional significant connections to this sensorimotor network were observed, involving prefrontal and precuneus regions. In healthy subjects, significant connections involved a posterior cortical network. In patients with discharges, this posterior network showed significantly low synchrony during the minute prior to discharge onset. In patients without discharges, this network showed the same level of synchrony as in healthy controls. Our findings suggest persistently high sensorimotor network synchrony, coupled with transiently (at least 1 min) low posterior network synchrony, may be a state predisposing to generalized spike-wave discharge onset. Our findings also show that EEG onset and associated MRI signal amplitude change is embedded in a considerably longer period of evolving brain network states before and after discharge events.
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Affiliation(s)
- Chayanin Tangwiriyasakul
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK
| | - Suejen Perani
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK.,Developmental Imaging and Biophysics Section, Developmental Neurosciences Program, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Maria Centeno
- Developmental Imaging and Biophysics Section, Developmental Neurosciences Program, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Siti Nurbaya Yaakub
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK
| | - Eugenio Abela
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK
| | - David W Carmichael
- Developmental Imaging and Biophysics Section, Developmental Neurosciences Program, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Mark P Richardson
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK.,King's College Hospital, London, UK
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40
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Routier L, Verny F, Barcia G, Chemaly N, Desguerre I, Colleaux L, Nabbout R. Exome sequencing findings in 27 patients with myoclonic-atonic epilepsy: Is there a major genetic factor? Clin Genet 2019; 96:254-260. [PMID: 31170314 DOI: 10.1111/cge.13581] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/22/2019] [Accepted: 06/02/2019] [Indexed: 01/31/2023]
Abstract
Myoclonic-atonic epilepsy (MAE) is thought to have a genetic etiology. Mutations in CHD2, SLC2A1 and SLC6A1 genes have been reported in few patients showing often intellectual disability prior to MAE onset. We aimed to explore putative causal genetic factors in MAE. We performed array-CGH and whole-exome sequencing in 27 patients. We considered non-synonymous variants, splice acceptor, donor site mutations, and coding insertions/deletions. A gene was causal when its mutations have been already linked to epilepsy or other brain diseases or when it has a putative function in neuronal excitability or brain development. We identified candidate disease-causing variants in 11 patients (41%). Single variants were found in some known epilepsy-associated genes (namely CHD2, KCNT1, KCNA2 and STXBP1) but not in others (SLC2A1 and SLC6A1). One new candidate gene SUN1 requires further validation. MAE shows underlying genetic heterogeneity with only few cases linked to mutations in genes reported in developmental and epileptic encephalopathies.
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Affiliation(s)
- Laura Routier
- Reference Centre for Rare Epilepsies, Pediatric Neurology, Necker Enfants-Malades Hospital, Paris, France.,Pediatric Neurology, Amiens-Picardie University Hospital, Amiens, France.,GRAMFC-INSERM U1105, UPJV, Amiens, France
| | - Florine Verny
- Reference Centre for Rare Epilepsies, Pediatric Neurology, Necker Enfants-Malades Hospital, Paris, France.,INSERM UMR1163, Translational Research for Neurological Disorders, Imagine Institute, Paris-Descartes University, Paris, France
| | - Giulia Barcia
- Clinical Genetics, Necker Enfants-Malades Hospital, Paris, France
| | - Nicole Chemaly
- Reference Centre for Rare Epilepsies, Pediatric Neurology, Necker Enfants-Malades Hospital, Paris, France.,INSERM UMR1163, Translational Research for Neurological Disorders, Imagine Institute, Paris-Descartes University, Paris, France
| | - Isabelle Desguerre
- Reference Centre for Rare Epilepsies, Pediatric Neurology, Necker Enfants-Malades Hospital, Paris, France
| | - Laurence Colleaux
- INSERM UMR1163, Translational Research for Neurological Disorders, Imagine Institute, Paris-Descartes University, Paris, France
| | - Rima Nabbout
- Reference Centre for Rare Epilepsies, Pediatric Neurology, Necker Enfants-Malades Hospital, Paris, France.,INSERM UMR1163, Translational Research for Neurological Disorders, Imagine Institute, Paris-Descartes University, Paris, France
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41
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Zastrow DB, Kohler JN, Bonner D, Reuter CM, Fernandez L, Grove ME, Fisk DG, Yang Y, Eng CM, Ward PA, Bick D, Worthey EA, Fisher PG, Ashley EA, Bernstein JA, Wheeler MT. A toolkit for genetics providers in follow-up of patients with non-diagnostic exome sequencing. J Genet Couns 2019; 28:213-228. [PMID: 30964584 PMCID: PMC7385984 DOI: 10.1002/jgc4.1119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 03/01/2019] [Accepted: 03/04/2019] [Indexed: 12/11/2022]
Abstract
There are approximately 7,000 rare diseases affecting 25-30 million Americans, with 80% estimated to have a genetic basis. This presents a challenge for genetics practitioners to determine appropriate testing, make accurate diagnoses, and conduct up-to-date patient management. Exome sequencing (ES) is a comprehensive diagnostic approach, but only 25%-41% of the patients receive a molecular diagnosis. The remaining three-fifths to three-quarters of patients undergoing ES remain undiagnosed. The Stanford Center for Undiagnosed Diseases (CUD), a clinical site of the Undiagnosed Diseases Network, evaluates patients with undiagnosed and rare diseases using a combination of methods including ES. Frequently these patients have non-diagnostic ES results, but strategic follow-up techniques identify diagnoses in a subset. We present techniques used at the CUD that can be adopted by genetics providers in clinical follow-up of cases where ES is non-diagnostic. Solved case examples illustrate different types of non-diagnostic results and the additional techniques that led to a diagnosis. Frequent approaches include segregation analysis, data reanalysis, genome sequencing, additional variant identification, careful phenotype-disease correlation, confirmatory testing, and case matching. We also discuss prioritization of cases for additional analyses.
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Affiliation(s)
- Diane B Zastrow
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Jennefer N Kohler
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Devon Bonner
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Chloe M Reuter
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Liliana Fernandez
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Megan E Grove
- Clinical Genomics Program, Stanford Health Care, Stanford, California
| | - Dianna G Fisk
- Clinical Genomics Program, Stanford Health Care, Stanford, California
| | | | | | | | - David Bick
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama
| | | | - Paul G Fisher
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Department of Neurology, Stanford University School of Medicine, Stanford, California
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Euan A Ashley
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Clinical Genomics Program, Stanford Health Care, Stanford, California
- Department of Genetics, Stanford University School of Medicine, Stanford, California
- Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Jonathan A Bernstein
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Matthew T Wheeler
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Department of Medicine, Stanford University School of Medicine, Stanford, California
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42
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Chourasia N, Ossó-Rivera H, Ghosh A, Von Allmen G, Koenig MK. Expanding the Phenotypic Spectrum of CACNA1H Mutations. Pediatr Neurol 2019; 93:50-55. [PMID: 30686625 DOI: 10.1016/j.pediatrneurol.2018.11.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 10/29/2018] [Accepted: 11/23/2018] [Indexed: 10/27/2022]
Abstract
BACKGROUND The CACNA1H gene mutations encoding the α1H subunit of Cav3.2 T-type calcium channels have been associated with generalized epilepsy. Focal or multifocal epilepsy and systemic (immunologic and gastrointestinal) involvement associated with these mutations have not been described previously. We detail the clinical characteristics of five patients with CACNA1H mutations and expand its phenotypic spectrum. METHODS A case series of five patients with pathogenic CACNA1H mutations was evaluated. The pathogenicity of the mutations was predicted by polymorphism phenotyping (Polyphen-2) and sorting-intolerant-from-tolerant analysis. RESULTS Mean age of seizure onset was 8.2 ± 3.7 years. Three patients had de novo mutations in the CACNA1H gene, and two patients inherited the mutation from an asymptomatic parent. The patients experienced different types of seizures including absence, focal seizures without awareness, focal seizures with secondary generalization, and myoclonic, atonic, and generalized tonic-clonic seizures. Electroencephalography showed focal, multifocal, or generalized discharges. One patient had autism and global developmental delay. Two patients had failure to thrive and selective antibody deficiency. CONCLUSIONS CACNA1H mutations can be associated with susceptibility to develop generalized epilepsy and focal or multifocal epilepsy of varying severity. Phenotypic features involving other organ systems (immune, gastrointestinal) can occur in addition to epilepsy, developmental delay, and autism.
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Affiliation(s)
- Nitish Chourasia
- McGovern Medical School, UTHealth, Division of Child and Adolescent Neurology, Houston, Texas.
| | - Henry Ossó-Rivera
- McGovern Medical School, UTHealth, Division of Child and Adolescent Neurology, Houston, Texas
| | - Ankita Ghosh
- McGovern Medical School, UTHealth, Division of Child and Adolescent Neurology, Houston, Texas
| | - Gretchen Von Allmen
- McGovern Medical School, UTHealth, Division of Pediatric Epilepsy, Houston, Texas
| | - Mary Kay Koenig
- McGovern Medical School, UTHealth, Mitochondrial Center of Excellence, Houston, Texas
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43
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Rebellato P, Kaczynska D, Kanatani S, Rayyes IA, Zhang S, Villaescusa C, Falk A, Arenas E, Hermanson O, Louhivuori L, Uhlén P. The T-type Ca 2+ Channel Ca v3.2 Regulates Differentiation of Neural Progenitor Cells during Cortical Development via Caspase-3. Neuroscience 2019; 402:78-89. [PMID: 30677486 DOI: 10.1016/j.neuroscience.2019.01.015] [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: 07/05/2018] [Revised: 12/11/2018] [Accepted: 01/12/2019] [Indexed: 01/02/2023]
Abstract
Here we report that the low-voltage-dependent T-type calcium (Ca2+) channel Cav3.2, encoded by the CACNA1H gene, regulates neuronal differentiation during early embryonic brain development through activating caspase-3. At the onset of neuronal differentiation, neural progenitor cells exhibited spontaneous Ca2+ activity. This activity strongly correlated with the upregulation of CACNA1H mRNA. Cells exhibiting robust spontaneous Ca2+ signaling had increased caspase-3 activity unrelated to apoptosis. Inhibition of Cav3.2 by drugs or viral CACNA1H knock down resulted in decreased caspase-3 activity followed by suppressed neurogenesis. In contrast, when CACNA1H was overexpressed, increased neurogenesis was detected. Cortical slices from Cacna1h knockout mice showed decreased spontaneous Ca2+ activity, a significantly lower protein level of cleaved caspase-3, and microanatomical abnormalities in the subventricular/ventricular and cortical plate zones when compared to their respective embryonic controls. In summary, we demonstrate a novel relationship between Cav3.2 and caspase-3 signaling that affects neurogenesis in the developing brain.
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Affiliation(s)
- Paola Rebellato
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Dagmara Kaczynska
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Shigeaki Kanatani
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Ibrahim Al Rayyes
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Songbai Zhang
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Carlos Villaescusa
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Anna Falk
- Department of Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Ernest Arenas
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Ola Hermanson
- Department of Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Lauri Louhivuori
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
| | - Per Uhlén
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
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44
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Garcia-Caballero A, Gandini MA, Huang S, Chen L, Souza IA, Dang YL, Stutts MJ, Zamponi GW. Cav3.2 calcium channel interactions with the epithelial sodium channel ENaC. Mol Brain 2019; 12:12. [PMID: 30736831 PMCID: PMC6368719 DOI: 10.1186/s13041-019-0433-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 02/04/2019] [Indexed: 11/10/2022] Open
Abstract
This study describes the functional interaction between Cav3.2 calcium channels and the Epithelial Sodium Channel (ENaC). β-ENaC subunits showed overlapping expression with endogenous Cav3.2 calcium channels in the thalamus and hypothalamus as detected by immunostaining. Moreover, β- and γ-ENaC subunits could be co-immunoprecipitated with Cav3.2 calcium channels from brain lysates, dorsal horn and lumbar dorsal root ganglia. Mutation of a cluster of lysines present in the intracellular N-terminus region of β-ENaC (K4R/ K5R/ K9R/ K16R/ K23R) reduced interactions with Cav3.2 calcium channels. Αβγ-ENaC channels enhanced Cav3.2 calcium channel trafficking to the plasma membrane in tsA-201 cells. This effect was reciprocal such that Cav3.2 channel expression also enhanced β-ENaC trafficking to the cell surface. T-type current density was increased when fully assembled αβγ-ENaC channels were transiently expressed in CAD cells, a neuronal derived cell line. Altogether, these findings reveal ENaC as an interactor and potential regulator of Cav3.2 calcium channels expressed in neuronal tissues.
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Affiliation(s)
- Agustin Garcia-Caballero
- Molecular Neuroscience, Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, T2N 4N1, Canada
| | - Maria A Gandini
- Molecular Neuroscience, Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, T2N 4N1, Canada
| | - Shuo Huang
- Molecular Neuroscience, Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, T2N 4N1, Canada
| | - Lina Chen
- Molecular Neuroscience, Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, T2N 4N1, Canada
| | - Ivana A Souza
- Molecular Neuroscience, Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, T2N 4N1, Canada
| | - Yan L Dang
- Cystic Fibrosis Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - M Jackson Stutts
- Cystic Fibrosis Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Gerald W Zamponi
- Molecular Neuroscience, Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, T2N 4N1, Canada.
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45
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Wang M, Greenberg DA, Stewart WCL. Replication, reanalysis, and gene expression: ME2 and genetic generalized epilepsy. Epilepsia 2019; 60:539-546. [PMID: 30719716 DOI: 10.1111/epi.14654] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 12/28/2018] [Accepted: 01/04/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Genetic generalized epilepsy (GGE) consists of epileptic syndromes with overlapping symptoms and is considered to be largely genetic. Previous cosegregation and association studies have pointed to malic enzyme 2 (ME2) as a candidate susceptibility gene for adolescent-onset GGE. In this article, we present new evidence supporting ME2's involvement in GGE. METHODS To definitively test ME2's influence on GGE, we used 3 different approaches. First, we compared a newly recruited GGE cohort with an ethnically matched reference sample from 1000 Genomes Project, using an efficient test of association (POPFAM+). Second, we used POPFAM+ to reanalyze a previously collected data set, wherein the original controls were replaced with ethnically matched reference samples to minimize the confounding effect of population stratification. Third, in a post hoc analysis of expression data from healthy human prefrontal cortex, we identified single nucleotide polymorphisms (SNPs) influencing ME2 messenger RNA (mRNA) expression; and then we tested those same SNPs for association with GGE in a large case-control cohort. RESULTS First, in the analysis of our newly recruited GGE Cohort, we found a strong association between an ME2 SNP and GGE (P = 0.0006 at rs608781). Second, in the reanalysis of previously collected data, we confirmed the Greenberg et al (2005) finding of a GGE-associated ME2 risk haplotype. Third, in the post hoc ME2 expression analysis, we found evidence for a possible link between GGE and ME2 gene expression in human brain. SIGNIFICANCE Overall, our research, and the research of others, provides compelling evidence that ME2 influences susceptibility to adolescent-onset GGE.
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Affiliation(s)
- Meng Wang
- The Research Institute at Nationwide Children's Hospital, Nationwide Children's Hospital, Columbus, Ohio
| | | | - William C L Stewart
- The Research Institute at Nationwide Children's Hospital, Nationwide Children's Hospital, Columbus, Ohio.,Department of Statistics, The Ohio State University, Columbus, Ohio.,Department of Pediatrics, The Ohio State University, Columbus, Ohio
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46
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Salvati KA, Beenhakker MP. Out of thin air: Hyperventilation-triggered seizures. Brain Res 2019; 1703:41-52. [PMID: 29288644 PMCID: PMC6546426 DOI: 10.1016/j.brainres.2017.12.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/29/2017] [Accepted: 12/27/2017] [Indexed: 12/11/2022]
Abstract
Voluntary hyperventilation triggers seizures in the vast majority of people with absence epilepsy. The mechanisms that underlie this phenomenon remain unknown. Herein, we review observations - many made long ago - that provide insight into the relationship between breathing and absence seizures.
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Affiliation(s)
- Kathryn A Salvati
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22903, United States
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22903, United States.
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47
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Wang D, Ragnarsson L, Lewis RJ. T-type Calcium Channels in Health and Disease. Curr Med Chem 2018; 27:3098-3122. [PMID: 30277145 DOI: 10.2174/0929867325666181001112821] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/28/2018] [Accepted: 08/30/2018] [Indexed: 12/12/2022]
Abstract
Low Voltage-Activated (LVA) T-type calcium channels are characterized by transient current and Low Threshold Spikes (LTS) that trigger neuronal firing and oscillatory behavior. Combined with their preferential localization in dendrites and their specific "window current", T-type calcium channels are considered to be key players in signal amplification and synaptic integration. Assisted by the emerging pharmacological tools, the structural determinants of channel gating and kinetics, as well as novel physiological and pathological functions of T-type calcium channels, are being uncovered. In this review, we provide an overview of structural determinants in T-type calcium channels, their involvement in disorders and diseases, the development of novel channel modulators, as well as Structure-Activity Relationship (SAR) studies that lead to rational drug design.
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Affiliation(s)
- Dan Wang
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Lotten Ragnarsson
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Richard J Lewis
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
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48
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Voltage-Dependent Calcium Channels, Calcium Binding Proteins, and Their Interaction in the Pathological Process of Epilepsy. Int J Mol Sci 2018; 19:ijms19092735. [PMID: 30213136 PMCID: PMC6164075 DOI: 10.3390/ijms19092735] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 01/08/2023] Open
Abstract
As an important second messenger, the calcium ion (Ca2+) plays a vital role in normal brain function and in the pathophysiological process of different neurodegenerative diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), and epilepsy. Ca2+ takes part in the regulation of neuronal excitability, and the imbalance of intracellular Ca2+ is a trigger factor for the occurrence of epilepsy. Several anti-epileptic drugs target voltage-dependent calcium channels (VDCCs). Intracellular Ca2+ levels are mainly controlled by VDCCs located in the plasma membrane, the calcium-binding proteins (CBPs) inside the cytoplasm, calcium channels located on the intracellular calcium store (particular the endoplasmic reticulum/sarcoplasmic reticulum), and the Ca2+-pumps located in the plasma membrane and intracellular calcium store. So far, while many studies have established the relationship between calcium control factors and epilepsy, the mechanism of various Ca2+ regulatory factors in epileptogenesis is still unknown. In this paper, we reviewed the function, distribution, and alteration of VDCCs and CBPs in the central nervous system in the pathological process of epilepsy. The interaction of VDCCs with CBPs in the pathological process of epilepsy was also summarized. We hope this review can provide some clues for better understanding the mechanism of epileptogenesis, and for the development of new anti-epileptic drugs targeting on VDCCs and CBPs.
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49
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Myers KA, Johnstone DL, Dyment DA. Epilepsy genetics: Current knowledge, applications, and future directions. Clin Genet 2018; 95:95-111. [PMID: 29992546 DOI: 10.1111/cge.13414] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 07/03/2018] [Accepted: 07/06/2018] [Indexed: 12/12/2022]
Abstract
The rapid pace of disease gene discovery has resulted in tremendous advances in the field of epilepsy genetics. Clinical testing with comprehensive gene panels, exomes, and genomes are now available and have led to higher diagnostic rates and insights into the underlying disease processes. As such, the contribution to the care of patients by medical geneticists, neurogeneticists and genetic counselors are significant; the dysmorphic examination, the necessary pre- and post-test counseling, the selection of the appropriate next-generation sequencing-based test(s), and the interpretation of sequencing results require a care provider to have a comprehensive working knowledge of the strengths and limitations of the available testing technologies. As the underlying mechanisms of the encephalopathies and epilepsies are better understood, there may be opportunities for the development of novel therapies based on an individual's own specific genotype. Drug screening with in vitro and in vivo models of epilepsy can potentially facilitate new treatment strategies. The future of epilepsy genetics will also probably include other-omic approaches such as transcriptomes, metabolomes, and the expanded use of whole genome sequencing to further improve our understanding of epilepsy and provide better care for those with the disease.
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Affiliation(s)
- K A Myers
- Department of Pediatrics, University of McGill, Montreal, Canada.,Research Institute of the McGill University Health Centre, Montreal, Canada
| | - D L Johnstone
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - D A Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada.,Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada
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50
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Clinical and genetic study of Tunisian families with genetic generalized epilepsy: contribution of CACNA1H and MAST4 genes. Neurogenetics 2018; 19:165-178. [PMID: 29948376 DOI: 10.1007/s10048-018-0550-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 06/01/2018] [Accepted: 06/03/2018] [Indexed: 12/11/2022]
Abstract
Genetic generalized epilepsies (GGE) (childhood absence epilepsy (CAE), juvenile myoclonic epilepsy (JME) and epilepsy with generalized tonic-clonic seizures (GTCS)) are mainly determined by genetic factors. Since few mutations were identified in rare families with autosomal dominant GGE, a polygenic inheritance was suspected in most patients. Recent studies on large American or European cohorts of sporadic cases showed that susceptibility genes were numerous although their variants were rare, making their identification difficult. Here, we reported clinical and genetic characteristics of 30 Tunisian GGE families, including 71 GGE patients. The phenotype was close to that in sporadic cases. Nineteen pedigrees had a homogeneous type of GGE (JME-CAE-CGTS), and 11 combined these epileptic syndromes. Rare non-synonymous variants were selected in probands using a targeted panel of 30 candidate genes and their segregation was determined in families. Molecular studies incriminated different genes, mainly CACNA1H and MAST4. The segregation of at least two variants in different genes in some pedigrees was compatible with the hypothesis of an oligogenic inheritance, which was in accordance with the relatively low frequency of consanguineous probands. Since at least 2 susceptibility genes were likely shared by different populations, genetic factors involved in the majority of Tunisian GGE families remain to be discovered. Their identification should be easier in families with a homogeneous type of GGE, in which an intra-familial genetic homogeneity could be suspected.
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