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Yu W, Hill SF, Zhu L, Demetriou Y, Reger F, Mattis J, Meisler MH. Dentate gyrus granule cells are a locus of pathology in Scn8a developmental encephalopathy. Neurobiol Dis 2024; 199:106591. [PMID: 38969233 DOI: 10.1016/j.nbd.2024.106591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 07/01/2024] [Accepted: 07/02/2024] [Indexed: 07/07/2024] Open
Abstract
Gain-of-function mutations in SCN8A cause developmental and epileptic encephalopathy (DEE), a disorder characterized by early-onset refractory seizures, deficits in motor and intellectual functions, and increased risk of sudden unexpected death in epilepsy. Altered activity of neurons in the corticohippocampal circuit has been reported in mouse models of DEE. We examined the effect of chronic seizures on gene expression in the hippocampus by single-nucleus RNA sequencing in mice expressing the patient mutation SCN8A-p.Asn1768Asp (N1768D). One hundred and eighty four differentially expressed genes were identified in dentate gyrus granule cells, many more than in other cell types. Electrophysiological recording from dentate gyrus granule cells demonstrated an elevated firing rate. Targeted reduction of Scn8a expression in the dentate gyrus by viral delivery of an shRNA resulted in doubling of median survival time from 4 months to 8 months, whereas delivery of shRNA to the CA1 and CA3 regions did not result in lengthened survival. These data indicate that granule cells of the dentate gyrus are a specific locus of pathology in SCN8A-DEE.
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Affiliation(s)
- Wenxi Yu
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Sophie F Hill
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Limei Zhu
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | | | - Faith Reger
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Joanna Mattis
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA; Department of Neurology, University of Michigan, Ann Arbor, MI, USA.
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Hill SF, Yu W, Ziobro J, Chalasani S, Reger F, Meisler MH. Long-Term Downregulation of the Sodium Channel Gene Scn8a Is Therapeutic in Mouse Models of SCN8A Epilepsy. Ann Neurol 2024; 95:754-759. [PMID: 38113311 PMCID: PMC11170564 DOI: 10.1002/ana.26861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 11/06/2023] [Accepted: 12/14/2023] [Indexed: 12/21/2023]
Abstract
OBJECTIVE De novo mutations of the voltage-gated sodium channel gene SCN8A cause developmental and epileptic encephalopathy (DEE). Most pathogenic variants result in gain-of-function changes in activity of the sodium channel Nav1.6, poorly controlled seizures, and significant comorbidities. In previous work, an antisense oligonucleotide (ASO) reduced Scn8a transcripts and increased lifespan after neonatal administration to a mouse model. Here, we tested long-term ASO treatment initiated after seizure onset, as required for clinical application. METHODS ASO treatment was initiated after observation of a convulsive seizure and repeated at 4 to 6 week intervals for 1 year. We also tested the long-term efficacy of an AAV10-short hairpin RNA (shRNA) virus administered on P1. RESULTS Repeated treatment with the Scn8a ASO initiated after seizure onset provided long-term survival and reduced seizure frequency during a 12 month observation period. A single treatment with viral shRNA was also protective during 12 months of observation. INTERPRETATION Downregulation of Scn8a expression that is initiated after the onset of seizures is effective for long-term treatment in a model of SCN8A-DEE. Repeated ASO administration or a single dose of viral shRNA prevented seizures and extended survival through 12 months of observation. ANN NEUROL 2024;95:754-759.
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Affiliation(s)
- Sophie F Hill
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Wenxi Yu
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Julie Ziobro
- Department of Pediatrics, University of Michigan, Ann Arbor, MI
| | - Sanjna Chalasani
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Faith Reger
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Miriam H Meisler
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
- Department of Neurology, University of Michigan, Ann Arbor, MI
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Hu B, Zhuang XL, Zhou L, Zhang G, Cooper DN, Wu DD. Deciphering the Role of Rapidly Evolving Conserved Elements in Primate Brain Development and Exploring Their Potential Involvement in Alzheimer's Disease. Mol Biol Evol 2024; 41:msae001. [PMID: 38175672 PMCID: PMC10798191 DOI: 10.1093/molbev/msae001] [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: 08/30/2023] [Revised: 12/27/2023] [Accepted: 12/29/2023] [Indexed: 01/05/2024] Open
Abstract
Although previous studies have identified human-specific accelerated regions as playing a key role in the recent evolution of the human brain, the characteristics and cellular functions of rapidly evolving conserved elements (RECEs) in ancestral primate lineages remain largely unexplored. Here, based on large-scale primate genome assemblies, we identify 888 RECEs that have been highly conserved in primates that exhibit significantly accelerated substitution rates in the ancestor of the Simiiformes. This primate lineage exhibits remarkable morphological innovations, including an expanded brain mass. Integrative multiomic analyses reveal that RECEs harbor sequences with potential cis-regulatory functions that are activated in the adult human brain. Importantly, genes linked to RECEs exhibit pronounced expression trajectories in the adult brain relative to the fetal stage. Furthermore, we observed an increase in the chromatin accessibility of RECEs in oligodendrocytes from individuals with Alzheimer's disease (AD) compared to that of a control group, indicating that these RECEs may contribute to brain aging and AD. Our findings serve to expand our knowledge of the genetic underpinnings of brain function during primate evolution.
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Affiliation(s)
- Benxia Hu
- Key Laboratory of Genetic Evolution & Animal Models, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Xiao-Lin Zhuang
- Key Laboratory of Genetic Evolution & Animal Models, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Long Zhou
- Center of Evolutionary and Organismal Biology, and Women’s Hospital, Zhejiang University School of Medicine, Hangzhou, Guangdong, China
- Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Guangdong, China
| | - Guojie Zhang
- Center of Evolutionary and Organismal Biology, and Women’s Hospital, Zhejiang University School of Medicine, Hangzhou, Guangdong, China
- Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Guangdong, China
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Dong-Dong Wu
- Key Laboratory of Genetic Evolution & Animal Models, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
- National Resource Center for Non-Human Primates, Kunming Primate Research Center, and National Research Facility for Phenotypic and Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
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Borowicz-Reutt K, Czernia J, Krawczyk M. Genetic Background of Epilepsy and Antiepileptic Treatments. Int J Mol Sci 2023; 24:16280. [PMID: 38003469 PMCID: PMC10671416 DOI: 10.3390/ijms242216280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Advanced identification of the gene mutations causing epilepsy syndromes is expected to translate into faster diagnosis and more effective treatment of these conditions. Over the last 5 years, approximately 40 clinical trials on the treatment of genetic epilepsies have been conducted. As a result, some medications that are not regular antiseizure drugs (e.g., soticlestat, fenfluramine, or ganaxolone) have been introduced to the treatment of drug-resistant seizures in Dravet, Lennox-Gastaut, maternally inherited chromosome 15q11.2-q13.1 duplication (Dup 15q) syndromes, and protocadherin 19 (PCDH 19)-clusterig epilepsy. And although the effects of soticlestat, fenfluramine, and ganaxolone are described as promising, they do not significantly affect the course of the mentioned epilepsy syndromes. Importantly, each of these syndromes is related to mutations in several genes. On the other hand, several mutations can occur within one gene, and different gene variants may be manifested in different disease phenotypes. This complex pattern of inheritance contributes to rather poor genotype-phenotype correlations. Hence, the detection of a specific mutation is not synonymous with a precise diagnosis of a specific syndrome. Bearing in mind that seizures develop as a consequence of the predominance of excitatory over inhibitory processes, it seems reasonable that mutations in genes encoding sodium and potassium channels, as well as glutamatergic and gamma-aminobutyric (GABA) receptors, play a role in the pathogenesis of epilepsy. In some cases, different pathogenic variants of the same gene can result in opposite functional effects, determining the effectiveness of therapy with certain medications. For instance, seizures related to gain-of-function (GoF) mutations in genes encoding sodium channels can be successfully treated with sodium channel blockers. On the contrary, the same drugs may aggravate seizures related to loss-of-function (LoF) variants of the same genes. Hence, knowledge of gene mutation-treatment response relationships facilitates more favorable selection of drugs for anticonvulsant therapy.
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Affiliation(s)
- Kinga Borowicz-Reutt
- Independent Unit of Experimental Neuropathophysiology, Department of Toxicology, Medical University of Lublin, Jaczewskiego 8b, 20-090 Lublin, Poland; (J.C.); (M.K.)
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Abstract
In recent years, there has been a significant increase in preclinical studies to test genetic therapies for epilepsy. Some of these therapies have advanced to clinical trials and are being tested in patients with monogenetic or focal refractory epilepsy. This article provides an overview of the current state of preclinical studies that show potential for clinical translation. Specifically, we focus on genetic therapies that have demonstrated a clear effect on seizures in animal models and have the potential to be translated to clinical settings. Both therapies targeting the cause of the disease and those that treat symptoms are discussed. We believe that the next few years will be crucial in determining the potential of genetic therapies for treating patients with epilepsy.
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Affiliation(s)
- James S. Street
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Yichen Qiu
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Gabriele Lignani
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
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Zybura AS, Sahoo FK, Hudmon A, Cummins TR. CaMKII Inhibition Attenuates Distinct Gain-of-Function Effects Produced by Mutant Nav1.6 Channels and Reduces Neuronal Excitability. Cells 2022; 11:2108. [PMID: 35805192 PMCID: PMC9266207 DOI: 10.3390/cells11132108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/16/2022] [Accepted: 06/27/2022] [Indexed: 11/17/2022] Open
Abstract
Aberrant Nav1.6 activity can induce hyperexcitability associated with epilepsy. Gain-of-function mutations in the SCN8A gene encoding Nav1.6 are linked to epilepsy development; however, the molecular mechanisms mediating these changes are remarkably heterogeneous and may involve post-translational regulation of Nav1.6. Because calcium/calmodulin-dependent protein kinase II (CaMKII) is a powerful modulator of Nav1.6 channels, we investigated whether CaMKII modulates disease-linked Nav1.6 mutants. Whole-cell voltage clamp recordings in ND7/23 cells show that CaMKII inhibition of the epilepsy-related mutation R850Q largely recapitulates the effects previously observed for WT Nav1.6. We also characterized a rare missense variant, R639C, located within a regulatory hotspot for CaMKII modulation of Nav1.6. Prediction software algorithms and electrophysiological recordings revealed gain-of-function effects for R639C mutant channel activity, including increased sodium currents and hyperpolarized activation compared to WT Nav1.6. Importantly, the R639C mutation ablates CaMKII phosphorylation at a key regulatory site, T642, and, in contrast to WT and R850Q channels, displays a distinct response to CaMKII inhibition. Computational simulations demonstrate that modeled neurons harboring the R639C or R850Q mutations are hyperexcitable, and simulating the effects of CaMKII inhibition on Nav1.6 activity in modeled neurons differentially reduced hyperexcitability. Acute CaMKII inhibition may represent a promising mechanism to attenuate gain-of-function effects produced by Nav1.6 mutations.
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Affiliation(s)
- Agnes S. Zybura
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Firoj K. Sahoo
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (F.K.S.); (A.H.)
| | - Andy Hudmon
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (F.K.S.); (A.H.)
| | - Theodore R. Cummins
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
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Duan F, Lv Y, Sun Z, Li J. Multi-scale Learning for Multimodal Neurophysiological Signals: Gait Pattern Classification as an Example. Neural Process Lett 2022. [DOI: 10.1007/s11063-021-10738-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Shiu FH, Wong JC, Yamamoto T, Lala T, Purcell RH, Owino S, Zhu D, Van Meir EG, Hall RA, Escayg A. Mice lacking full length Adgrb1 (Bai1) exhibit social deficits, increased seizure susceptibility, and altered brain development. Exp Neurol 2022; 351:113994. [PMID: 35114205 PMCID: PMC9817291 DOI: 10.1016/j.expneurol.2022.113994] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 12/20/2021] [Accepted: 01/24/2022] [Indexed: 01/11/2023]
Abstract
The adhesion G protein-coupled receptor BAI1/ADGRB1 plays an important role in suppressing angiogenesis, mediating phagocytosis, and acting as a brain tumor suppressor. BAI1 is also a critical regulator of dendritic spine and excitatory synapse development and interacts with several autism-relevant proteins. However, little is known about the relationship between altered BAI1 function and clinically relevant phenotypes. Therefore, we studied the effect of reduced expression of full length Bai1 on behavior, seizure susceptibility, and brain morphology in Adgrb1 mutant mice. We compared homozygous (Adgrb1-/-), heterozygous (Adgrb1+/-), and wild-type (WT) littermates using a battery of tests to assess social behavior, anxiety, repetitive behavior, locomotor function, and seizure susceptibility. We found that Adgrb1-/- mice showed significant social behavior deficits and increased vulnerability to seizures. Adgrb1-/- mice also showed delayed growth and reduced brain weight. Furthermore, reduced neuron density and increased apoptosis during brain development were observed in the hippocampus of Adgrb1-/- mice, while levels of astrogliosis and microgliosis were comparable to WT littermates. These results show that reduced levels of full length Bai1 is associated with a broader range of clinically relevant phenotypes than previously reported.
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Affiliation(s)
- Fu Hung Shiu
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA; Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, USA
| | - Jennifer C Wong
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Takahiro Yamamoto
- Department of Neurosurgery, School of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Trisha Lala
- Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, USA; Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Ryan H Purcell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Sharon Owino
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Dan Zhu
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Erwin G Van Meir
- Department of Neurosurgery, School of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA; O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Randy A Hall
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA.
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Wong JC, Butler KM, Shapiro L, Thelin JT, Mattison KA, Garber KB, Goldenberg PC, Kubendran S, Schaefer GB, Escayg A. Pathogenic in-Frame Variants in SCN8A: Expanding the Genetic Landscape of SCN8A-Associated Disease. Front Pharmacol 2021; 12:748415. [PMID: 34867351 PMCID: PMC8635767 DOI: 10.3389/fphar.2021.748415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/21/2021] [Indexed: 01/11/2023] Open
Abstract
Numerous SCN8A mutations have been identified, of which, the majority are de novo missense variants. Most mutations result in epileptic encephalopathy; however, some are associated with less severe phenotypes. Mouse models generated by knock-in of human missense SCN8A mutations exhibit seizures and a range of behavioral abnormalities. To date, there are only a few Scn8a mouse models with in-frame deletions or insertions, and notably, none of these mouse lines exhibit increased seizure susceptibility. In the current study, we report the generation and characterization of two Scn8a mouse models (ΔIRL/+ and ΔVIR/+) carrying overlapping in-frame deletions within the voltage sensor of domain 4 (DIVS4). Both mouse lines show increased seizure susceptibility and infrequent spontaneous seizures. We also describe two unrelated patients with the same in-frame SCN8A deletion in the DIV S5-S6 pore region, highlighting the clinical relevance of this class of mutations.
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Affiliation(s)
- Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Kameryn M Butler
- Department of Human Genetics, Emory University, Atlanta, GA, United States.,Greenwood Genetic Center, Greenwood, SC, United States
| | - Lindsey Shapiro
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Jacquelyn T Thelin
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Kari A Mattison
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Kathryn B Garber
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Paula C Goldenberg
- Department of Pediatrics and Medical Genetics, Harvard Medical School, Boston, MA, United States
| | - Shobana Kubendran
- Department of Pediatrics, Kansas University School of Medicine-Wichita, Wichita, KS, United States
| | - G Bradley Schaefer
- University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA, United States
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Autistic-like behavior, spontaneous seizures, and increased neuronal excitability in a Scn8a mouse model. Neuropsychopharmacology 2021; 46:2011-2020. [PMID: 33658654 PMCID: PMC8429750 DOI: 10.1038/s41386-021-00985-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 02/05/2023]
Abstract
Patients with SCN8A epileptic encephalopathy exhibit a range of clinical features, including multiple seizure types, movement disorders, and behavioral abnormalities, such as developmental delay, mild-to-severe intellectual disability, and autism. Recently, the de novo heterozygous SCN8A R1620L mutation was identified in an individual with autism, intellectual disability, and behavioral seizures without accompanying electrographic seizure activity. To date, the effects of SCN8A mutations that are primarily associated with behavioral abnormalities have not been studied in a mouse model. To better understand the phenotypic and functional consequences of the R1620L mutation, we used CRISPR/Cas9 technology to generate mice expressing the corresponding SCN8A amino acid substitution. Homozygous mutants exhibit tremors and a maximum lifespan of 22 days, while heterozygous mutants (RL/+) exhibit autistic-like behaviors, such as hyperactivity and learning and social deficits, increased seizure susceptibility, and spontaneous seizures. Current clamp analyses revealed a reduced threshold for firing action potentials in heterozygous CA3 pyramidal neurons and reduced firing frequency, suggesting that the R1620L mutation has both gain- and loss-of-function effects. In vivo calcium imaging using miniscopes in freely moving RL/+ mutants showed hyperexcitability of cortical excitatory neurons that is likely to increase seizure susceptibility. Finally, we found that oxcarbazepine and Huperzine A, a sodium channel blocker and reversible acetylcholinesterase inhibitor, respectively, were capable of conferring robust protection against induced seizures in RL/+ mutants. This mouse line will provide the opportunity to better understand the range of clinical phenotypes associated with SCN8A mutations and to develop new therapeutic approaches.
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Avazzadeh S, Quinlan LR, Reilly J, McDonagh K, Jalali A, Wang Y, McInerney V, Krawczyk J, Ding Y, Fitzgerald J, O'Sullivan M, Forman EB, Lynch SA, Ennis S, Feerick N, Reilly R, Li W, Shen X, Yang G, Lu Y, Peeters H, Dockery P, O'Brien T, Shen S, Gallagher L. NRXN1α +/- is associated with increased excitability in ASD iPSC-derived neurons. BMC Neurosci 2021; 22:56. [PMID: 34525970 PMCID: PMC8442436 DOI: 10.1186/s12868-021-00661-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 09/01/2021] [Indexed: 12/14/2022] Open
Abstract
Background NRXN1 deletions are identified as one of major rare risk factors for autism spectrum disorder (ASD) and other neurodevelopmental disorders. ASD has 30% co-morbidity with epilepsy, and the latter is associated with excessive neuronal firing. NRXN1 encodes hundreds of presynaptic neuro-adhesion proteins categorized as NRXN1α/β/γ. Previous studies on cultured cells show that the short NRXN1β primarily exerts excitation effect, whereas the long NRXN1α which is more commonly deleted in patients involves in both excitation and inhibition. However, patient-derived models are essential for understanding functional consequences of NRXN1α deletions in human neurons. We recently derived induced pluripotent stem cells (iPSCs) from five controls and three ASD patients carrying NRXN1α+/- and showed increased calcium transients in patient neurons. Methods In this study we investigated the electrophysiological properties of iPSC-derived cortical neurons in control and ASD patients carrying NRXN1α+/- using patch clamping. Whole genome RNA sequencing was carried out to further understand the potential underlying molecular mechanism. Results NRXN1α+/- cortical neurons were shown to display larger sodium currents, higher AP amplitude and accelerated depolarization time. RNASeq analyses revealed transcriptomic changes with significant upregulation glutamatergic synapse and ion channels/transporter activity including voltage-gated potassium channels (GRIN1, GRIN3B, SLC17A6, CACNG3, CACNA1A, SHANK1), which are likely to couple with the increased excitability in NRXN1α+/- cortical neurons. Conclusions Together with recent evidence of increased calcium transients, our results showed that human NRXN1α+/- isoform deletions altered neuronal excitability and non-synaptic function, and NRXN1α+/- patient iPSCs may be used as an ASD model for therapeutic development with calcium transients and excitability as readouts. Supplementary Information The online version contains supplementary material available at 10.1186/s12868-021-00661-0.
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Affiliation(s)
- Sahar Avazzadeh
- School of Medicine, Regenerative Medicine Institute, Biomedical Science Building BMS-1021, National University of Ireland Galway, Dangan, Ireland
| | - Leo R Quinlan
- Physiology and Cellular Physiology Research Laboratory, School of Medicine, CÚRAM SFI Centre for Research in Medical Devices, National University of Ireland (NUI), Galway, Ireland
| | - Jamie Reilly
- School of Medicine, Regenerative Medicine Institute, Biomedical Science Building BMS-1021, National University of Ireland Galway, Dangan, Ireland
| | - Katya McDonagh
- School of Medicine, Regenerative Medicine Institute, Biomedical Science Building BMS-1021, National University of Ireland Galway, Dangan, Ireland
| | | | - Yanqin Wang
- School of Medicine, Regenerative Medicine Institute, Biomedical Science Building BMS-1021, National University of Ireland Galway, Dangan, Ireland.,Department of Physiology, College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Veronica McInerney
- HRB Clinical Research Facility, National University of Ireland (NUI), Galway, Ireland
| | - Janusz Krawczyk
- Department of Haematology, Galway University Hospital, Galway, Ireland
| | - Yicheng Ding
- School of Medicine, Regenerative Medicine Institute, Biomedical Science Building BMS-1021, National University of Ireland Galway, Dangan, Ireland
| | | | - Matthew O'Sullivan
- Trinity Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Eva B Forman
- Children's University Hospital, Temple Street, Dublin, Ireland
| | - Sally A Lynch
- Children's University Hospital, Temple Street, Dublin, Ireland.,Department of Clinical Genetics, OLCHC, Dublin 12, Ireland
| | - Sean Ennis
- School of Medicine and Medical Science, UCD Academic Centre On Rare Diseases, University College Dublin, Dublin, Ireland
| | - Niamh Feerick
- Centre for Bioengineering, Trinity College Institute of Neuroscience, School of Medicine, School of Engineering, Trinity College Dublin, Dublin, Ireland
| | - Richard Reilly
- Centre for Bioengineering, Trinity College Institute of Neuroscience, School of Medicine, School of Engineering, Trinity College Dublin, Dublin, Ireland
| | - Weidong Li
- Bio-X Institutes, Key Laboratory for the Genetics of Development and Neuropsychiatric Disorders (Ministry of Education), Shanghai Key Laboratory of Psychotic Disorders, and Brain Science and Technology Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Xu Shen
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, 138 Xianlin Road, Nanjing, 210023, China
| | - Guangming Yang
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
| | - Yin Lu
- College of Pharmacy, Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine (TCM) Prevention and Treatment of Tumor, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Hilde Peeters
- Centre for Human Genetics, University Hospital Leuven, KU Leuven, 3000, Leuven, Belgium
| | - Peter Dockery
- Centre for Microscopy and Imaging, Anatomy, School of Medicine, National University of Ireland (NUI), Galway, Ireland
| | - Timothy O'Brien
- School of Medicine, Regenerative Medicine Institute, Biomedical Science Building BMS-1021, National University of Ireland Galway, Dangan, Ireland
| | - Sanbing Shen
- School of Medicine, Regenerative Medicine Institute, Biomedical Science Building BMS-1021, National University of Ireland Galway, Dangan, Ireland. .,FutureNeuro Research Centre, Royal College of Surgeons in Ireland, Dublin, D02, Ireland.
| | - Louise Gallagher
- Trinity Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
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12
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Zybura A, Hudmon A, Cummins TR. Distinctive Properties and Powerful Neuromodulation of Na v1.6 Sodium Channels Regulates Neuronal Excitability. Cells 2021; 10:cells10071595. [PMID: 34202119 PMCID: PMC8307729 DOI: 10.3390/cells10071595] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/20/2021] [Accepted: 06/21/2021] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (Navs) are critical determinants of cellular excitability. These ion channels exist as large heteromultimeric structures and their activity is tightly controlled. In neurons, the isoform Nav1.6 is highly enriched at the axon initial segment and nodes, making it critical for the initiation and propagation of neuronal impulses. Changes in Nav1.6 expression and function profoundly impact the input-output properties of neurons in normal and pathological conditions. While mutations in Nav1.6 may cause channel dysfunction, aberrant changes may also be the result of complex modes of regulation, including various protein-protein interactions and post-translational modifications, which can alter membrane excitability and neuronal firing properties. Despite decades of research, the complexities of Nav1.6 modulation in health and disease are still being determined. While some modulatory mechanisms have similar effects on other Nav isoforms, others are isoform-specific. Additionally, considerable progress has been made toward understanding how individual protein interactions and/or modifications affect Nav1.6 function. However, there is still more to be learned about how these different modes of modulation interact. Here, we examine the role of Nav1.6 in neuronal function and provide a thorough review of this channel’s complex regulatory mechanisms and how they may contribute to neuromodulation.
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Affiliation(s)
- Agnes Zybura
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Andy Hudmon
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA;
| | - Theodore R. Cummins
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
- Correspondence:
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13
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Prakash C, Mishra M, Kumar P, Kumar V, Sharma D. Response of Voltage-Gated Sodium and Calcium Channels Subtypes on Dehydroepiandrosterone Treatment in Iron-Induced Epilepsy. Cell Mol Neurobiol 2021; 41:279-292. [PMID: 32318899 DOI: 10.1007/s10571-020-00851-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/14/2020] [Indexed: 12/28/2022]
Abstract
Epilepsy is a neurological disorder characterized by the occurrence of spontaneous and recurrent seizures. In post-traumatic epilepsy (PTE), the mechanism of epileptogenesis is very complex and seems to be linked with voltage-gated ion channels. Dehydroepiandrosterone (DHEA), a neurosteroid have shown beneficial effect against various neurological disorders. We investigated antiepileptic effect of DHEA with respect to expression of voltage-gated ion channels subtypes in iron-induced epilepsy. Iron (FeCl3) solution was intracartically injected to induce epilepsy in rats and DHEA was intraperitoneally administered for 21 days. Results showed markedly increased epileptiform seizures activity along with up-regulation of Nav1.1 and Nav1.6, and down-regulation of Cav2.1α at the mRNA and protein level in the cortex and hippocampus of epileptic rats. Moreover, the study demonstrated that these channels subtypes were predominantly expressed in the neurons. DHEA treatment has countered the epileptic seizures, down-regulated Nav1.1 and Nav1.6, and up-regulated Cav2.1α without affecting their cellular localization. In conclusion, the present study demonstrates antiepileptic potential of DHEA, escorted by regulation of Nav1.1, Nav1.6, and Cav2.1α subtypes in the neurons of iron-induced epileptic rats.
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Affiliation(s)
- Chandra Prakash
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Monika Mishra
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Pavan Kumar
- Department of Developmental Neurogenetics, Medical University of South Carolina, Charleston, SC, USA
| | - Vikas Kumar
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Deepak Sharma
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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14
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Abstract
The voltage-gated sodium channel α-subunit genes comprise a highly conserved gene family. Mutations of three of these genes, SCN1A, SCN2A and SCN8A, are responsible for a significant burden of neurological disease. Recent progress in identification and functional characterization of patient variants is generating new insights and novel approaches to therapy for these devastating disorders. Here we review the basic elements of sodium channel function that are used to characterize patient variants. We summarize a large body of work using global and conditional mouse mutants to characterize the in vivo roles of these channels. We provide an overview of the neurological disorders associated with mutations of the human genes and examples of the effects of patient mutations on channel function. Finally, we highlight therapeutic interventions that are emerging from new insights into mechanisms of sodium channelopathies.
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15
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Huguenard JR. Perspective: Is Cortical Hyperexcitability the Only Path to Generalized Absence Epilepsy? Epilepsy Curr 2020; 20:59S-61S. [PMID: 33287573 PMCID: PMC7726732 DOI: 10.1177/1535759720959325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- John R Huguenard
- Department of Neurology and Neurological Sciences, 10624Stanford University, Neurosciences Building, 290 Jane Stanford Way, Stanford, CA 94305, USA
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16
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Li J, Leverton LK, Naganatanahalli LM, Christian-Hinman CA. Seizure burden fluctuates with the female reproductive cycle in a mouse model of chronic temporal lobe epilepsy. Exp Neurol 2020; 334:113492. [PMID: 33007292 DOI: 10.1016/j.expneurol.2020.113492] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/22/2020] [Accepted: 09/28/2020] [Indexed: 12/30/2022]
Abstract
Women with catamenial epilepsy often experience increased seizure burden near the time of ovulation (periovulatory) or menstruation (perimenstrual). To date, a rodent model of chronic temporal lobe epilepsy (TLE) that exhibits similar endogenous fluctuations in seizures has not been identified. Here, we investigated whether seizure burden changes with the estrous cycle in the intrahippocampal kainic acid (IHKA) mouse model of TLE. Adult female IHKA mice and saline-injected controls were implanted with EEG electrodes in the ipsilateral hippocampus. At one and two months post-injection, 24/7 video-EEG recordings were collected and estrous cycle stage was assessed daily. Seizures were detected using a custom convolutional neural network machine learning process. Seizure burden was compared within each mouse between diestrus and combined proestrus and estrus days (pro/estrus) at two months post-injection. IHKA mice showed higher seizure burden on pro/estrus compared with diestrus, characterized by increased time in seizures and longer seizure duration. When all IHKA mice were included, no group differences were observed in seizure frequency or EEG power. However, increased baseline seizure burden on diestrus was correlated with larger cycle-associated differences, and when analyses were restricted to mice that showed the severe epilepsy typical of the IHKA model, increased seizure frequency on pro/estrus was also revealed. Controls showed no differences in EEG parameters with cycle stage. These results suggest that the stages of proestrus and estrus are associated with higher seizure burden in IHKA mice. The IHKA model may thus recapitulate at least some aspects of reproductive cycle-associated seizure clustering.
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Affiliation(s)
- Jiang Li
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Leanna K Leverton
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Laxmi Manisha Naganatanahalli
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Catherine A Christian-Hinman
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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17
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D'Adamo MC, Liantonio A, Conte E, Pessia M, Imbrici P. Ion Channels Involvement in Neurodevelopmental Disorders. Neuroscience 2020; 440:337-359. [PMID: 32473276 DOI: 10.1016/j.neuroscience.2020.05.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/16/2020] [Accepted: 05/19/2020] [Indexed: 12/14/2022]
Abstract
Inherited and sporadic mutations in genes encoding for brain ion channels, affecting membrane expression or biophysical properties, have been associated with neurodevelopmental disorders characterized by epilepsy, cognitive and behavioral deficits with significant phenotypic and genetic heterogeneity. Over the years, the screening of a growing number of patients and the functional characterization of newly identified mutations in ion channels genes allowed to recognize new phenotypes and to widen the clinical spectrum of known diseases. Furthermore, advancements in understanding disease pathogenesis at atomic level or using patient-derived iPSCs and animal models have been pivotal to orient therapeutic intervention and to put the basis for the development of novel pharmacological options for drug-resistant disorders. In this review we will discuss major improvements and critical issues concerning neurodevelopmental disorders caused by dysfunctions in brain sodium, potassium, calcium, chloride and ligand-gated ion channels.
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Affiliation(s)
- Maria Cristina D'Adamo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Malta
| | | | - Elena Conte
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Italy
| | - Mauro Pessia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Malta; Department of Physiology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Italy.
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18
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Tanioka M, Park WK, Shim I, Kim K, Choi S, Kim UJ, Lee KH, Hong SK, Lee BH. Neuroprotection from Excitotoxic Injury by Local Administration of Lipid Emulsion into the Brain of Rats. Int J Mol Sci 2020; 21:ijms21082706. [PMID: 32295117 PMCID: PMC7215821 DOI: 10.3390/ijms21082706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/10/2020] [Accepted: 04/12/2020] [Indexed: 01/10/2023] Open
Abstract
Lipid emulsion was recently shown to attenuate cell death caused by excitotoxic conditions in the heart. There are key similarities between neurons and cardiomyocytes, such as excitability and conductibility, which yield vulnerability to excitotoxic conditions. However, systematic investigations on the protective effects of lipid emulsion in the central nervous system are still lacking. This study aimed to determine the neuroprotective effects of lipid emulsion in an in vivo rat model of kainic acid-induced excitotoxicity through intrahippocampal microinjections. Kainic acid and/or lipid emulsion-injected rats were subjected to the passive avoidance test and elevated plus maze for behavioral assessment. Rats were sacrificed at 24 h and 72 h after kainic acid injections for molecular study, including immunoblotting and qPCR. Brains were also cryosectioned for morphological analysis through cresyl violet staining and Fluorojade-C staining. Anxiety and memory functions were significantly preserved in 1% lipid emulsion-treated rats. Lipid emulsion was dose-dependent on the protein expression of β-catenin and the phosphorylation of GSK3-β and Akt. Wnt1 mRNA expression was elevated in lipid emulsion-treated rats compared to the vehicle. Neurodegeneration was significantly reduced mainly in the CA1 region with increased cell survival. Our results suggest that lipid emulsion has neuroprotective effects against excitotoxic conditions in the brain and may provide new insight into its potential therapeutic utility.
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Affiliation(s)
- Motomasa Tanioka
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Wyun Kon Park
- Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul 03722, Korea;
| | - Insop Shim
- Department of Physiology, School of Medicine, Kyung Hee University, Seoul 02447, Korea;
| | - Kyeongmin Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Songyeon Choi
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Un Jeng Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
| | - Kyung Hee Lee
- Department of Dental Hygiene, Division of Health Science, Dongseo University, Busan 47011, Korea;
| | - Seong-Karp Hong
- Division of Biomedical Engineering, Mokwon University, Daejeon 35349, Korea;
| | - Bae Hwan Lee
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
- Correspondence: ; Tel.: + 82-2-2228-1711
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19
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Lenk GM, Jafar-Nejad P, Hill SF, Huffman LD, Smolen CE, Wagnon JL, Petit H, Yu W, Ziobro J, Bhatia K, Parent J, Giger RJ, Rigo F, Meisler MH. Scn8a Antisense Oligonucleotide Is Protective in Mouse Models of SCN8A Encephalopathy and Dravet Syndrome. Ann Neurol 2020; 87:339-346. [PMID: 31943325 PMCID: PMC7064908 DOI: 10.1002/ana.25676] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 01/07/2020] [Accepted: 01/07/2020] [Indexed: 12/19/2022]
Abstract
Objective SCN8A encephalopathy is a developmental and epileptic encephalopathy (DEE) caused by de novo gain‐of‐function mutations of sodium channel Nav1.6 that result in neuronal hyperactivity. Affected individuals exhibit early onset drug‐resistant seizures, developmental delay, and cognitive impairment. This study was carried out to determine whether reducing the abundance of the Scn8a transcript with an antisense oligonucleotide (ASO) would delay seizure onset and prolong survival in a mouse model of SCN8A encephalopathy. Methods ASO treatment was tested in a conditional mouse model with Cre‐dependent expression of the pathogenic patient SCN8A mutation p.Arg1872Trp (R1872W). This model exhibits early onset of seizures, rapid progression, and 100% penetrance. An Scn1a+/− haploinsufficient mouse model of Dravet syndrome was also treated. ASO was administered by intracerebroventricular injection at postnatal day 2, followed in some cases by stereotactic injection at postnatal day 30. Results We observed a dose‐dependent increase in length of survival from 15 to 65 days in the Scn8a‐R1872W/+ mice treated with ASO. Electroencephalographic recordings were normal prior to seizure onset. Weight gain and activity in an open field were unaffected, but treated mice were less active in a wheel running assay. A single treatment with Scn8a ASO extended survival of Dravet syndrome mice from 3 weeks to >5 months. Interpretation Reduction of Scn8a transcript by 25 to 50% delayed seizure onset and lethality in mouse models of SCN8A encephalopathy and Dravet syndrome. Reduction of SCN8A transcript is a promising approach to treatment of intractable childhood epilepsies. Ann Neurol 2020;87:339–346
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Affiliation(s)
- Guy M Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | | | - Sophie F Hill
- Department of Human Genetics, University of Michigan, Ann Arbor, MI.,Neuroscience Program, Ann Arbor, MI
| | - Lucas D Huffman
- Neuroscience Program, Ann Arbor, MI.,Department of Cell and Developmental Biology, Ann Arbor, MI
| | - Corrine E Smolen
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Jacy L Wagnon
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Hayley Petit
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Wenxi Yu
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Julie Ziobro
- Department of Neurology, University of Michigan, Ann Arbor, MI
| | - Kritika Bhatia
- Department of Neurology, University of Michigan, Ann Arbor, MI
| | - Jack Parent
- Department of Neurology, University of Michigan, Ann Arbor, MI
| | - Roman J Giger
- Neuroscience Program, Ann Arbor, MI.,Department of Cell and Developmental Biology, Ann Arbor, MI.,Department of Neurology, University of Michigan, Ann Arbor, MI
| | | | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI.,Neuroscience Program, Ann Arbor, MI.,Department of Neurology, University of Michigan, Ann Arbor, MI
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20
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Pan Y, Cummins TR. Distinct functional alterations in SCN8A epilepsy mutant channels. J Physiol 2020; 598:381-401. [PMID: 31715021 PMCID: PMC7216308 DOI: 10.1113/jp278952] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 11/12/2019] [Indexed: 01/12/2023] Open
Abstract
KEY POINTS Mutations in the SCN8A gene cause early infantile epileptic encephalopathy. We characterize a new epilepsy-related SCN8A mutation, R850Q, in the human SCN8A channel and present gain-of-function properties of the mutant channel. Systematic comparison of R850Q with three other SCN8A epilepsy mutations, T761I, R1617Q and R1872Q, identifies one common dysfunction in resurgent current, although these mutations alter distinct properties of the channel. Computational simulations in two different neuron models predict an increased excitability of neurons carrying these mutations, which explains the over-excitation that underlies seizure activities in patients. These data provide further insight into the mechanism of SCN8A-related epilepsy and reveal subtle but potentially important distinction of functional characterization performed in the human vs. rodent channels. ABSTRACT SCN8A is a novel causal gene for early infantile epileptic encephalopathy. It is well accepted that gain-of-function mutations in SCN8A underlie the disorder, although the remarkable heterogeneity of its clinical presentation and poor treatment response demand a better understanding of the disease mechanisms. Here, we characterize a new epilepsy-related SCN8A mutation, R850Q, in human Nav1.6. We show that it is a gain-of-function mutation, with a hyperpolarizing shift in voltage dependence of activation, a two-fold increase of persistent current and a slowed decay of resurgent current. We systematically compare its biophysics with three other SCN8A epilepsy mutations, T767I, R1617Q and R1872Q, in the human Nav1.6 channel. Although all of these mutations are gain-of-function, the mutations affect different aspects of channel properties. One commonality that we discovered is an alteration of resurgent current kinetics, although the mechanisms by which resurgent currents are augmented remain unclear for all of the mutations. Computational simulations predict an increased excitability of neurons carrying these mutations with differential enhancement by open channel blockade.
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Affiliation(s)
- Yanling Pan
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, IN, USA
| | - Theodore R Cummins
- Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, IN, USA
- Department of Biology, School of Science, IUPUI, IN, USA
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21
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Shapiro L, Wong JC, Escayg A. Reduced cannabinoid 2 receptor activity increases susceptibility to induced seizures in mice. Epilepsia 2019; 60:2359-2369. [PMID: 31758544 DOI: 10.1111/epi.16388] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/22/2019] [Accepted: 10/22/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVE The endocannabinoid system (ECS) is comprised of cannabinoid receptors 1 and 2 (CB1R and CB2R), endogenous ligands, and regulatory enzymes, and serves to regulate several important physiological functions throughout the brain and body. Recent evidence suggests that the ECS may be a promising target for the treatment of epilepsy, including epilepsy subtypes that arise from mutations in the voltage-gated sodium channel SCN1A. The objective of this study was to explore the effects of modulating CB2R activity on seizure susceptibility. METHODS We examined susceptibility to induced seizures using a number of paradigms in CB2R knockout mice (Cnr2-/- ), and determined the effects of the CB2R agonist, JWH-133, and the CB2R antagonist, SR144528, on seizure susceptibility in wild-type mice. We also examined seizure susceptibility in Cnr2 mutants harboring the human SCN1A R1648H (RH) epilepsy mutation and performed Electroencephalography (EEG) analysis to determine whether the loss of CB2Rs would increase spontaneous seizure frequency in Scn1a RH mutant mice. RESULTS Both heterozygous (Cnr2+/- ) and homozygous (Cnr2-/- ) knockout mice exhibited increased susceptibility to pentylenetetrazole (PTZ)-induced seizures. The CB2R agonist JWH-133 did not significantly alter seizure susceptibility in wild-type mice; however, administration of the CB2R antagonist SR144528 resulted in increased susceptibility to PTZ-induced seizures. In offspring from a cross between the Cnr2 × RH lines, both Cnr2 and RH mutants were susceptible to PTZ-induced seizures; however, seizure susceptibility was not significantly increased in mutants expressing both mutations. No spontaneous seizures were observed in either RH or Cnr2/RH mutants during 336-504 hours of continuous EEG recordings. SIGNIFICANCE Our results demonstrate that reduced CB2R activity is associated with increased seizure susceptibility. CB2Rs might therefore provide a therapeutic target for the treatment of some forms of epilepsy.
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Affiliation(s)
- Lindsey Shapiro
- Department of Human Genetics, Emory University, Atlanta, Georgia
| | - Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, Georgia
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, Georgia
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22
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Inglis GAS, Wong JC, Butler KM, Thelin JT, Mistretta OC, Wu X, Lin X, English AW, Escayg A. Mutations in the Scn8a DIIS4 voltage sensor reveal new distinctions among hypomorphic and null Na v 1.6 sodium channels. GENES BRAIN AND BEHAVIOR 2019; 19:e12612. [PMID: 31605437 DOI: 10.1111/gbb.12612] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/30/2019] [Accepted: 09/22/2019] [Indexed: 12/14/2022]
Abstract
Mutations in the voltage-gated sodium channel gene SCN8A cause a broad range of human diseases, including epilepsy, intellectual disability, and ataxia. Here we describe three mouse lines on the C57BL/6J background with novel, overlapping mutations in the Scn8a DIIS4 voltage sensor: an in-frame 9 bp deletion (Δ9), an in-frame 3 bp insertion (∇3) and a 35 bp deletion that results in a frameshift and the generation of a null allele (Δ35). Scn8a Δ9/+ and Scn8a ∇3/+ heterozygous mutants display subtle motor deficits, reduced acoustic startle response, and are resistant to induced seizures, suggesting that these mutations reduce activity of the Scn8a channel protein, Nav 1.6. Heterozygous Scn8a Δ35/+ mutants show no alterations in motor function or acoustic startle response, but are resistant to induced seizures. Homozygous mutants from each line exhibit premature lethality and severe motor impairments, ranging from uncoordinated gait with tremor (Δ9 and ∇3) to loss of hindlimb control (Δ35). Scn8a Δ9/Δ9 and Scn8a ∇3/∇3 homozygous mutants also exhibit impaired nerve conduction velocity, while normal nerve conduction was observed in Scn8a Δ35/Δ35 homozygous mice. Our results suggest that hypomorphic mutations that reduce Nav 1.6 activity will likely result in different clinical phenotypes compared to null alleles. These three mouse lines represent a valuable opportunity to examine the phenotypic impacts of hypomorphic and null Scn8a mutations without the confound of strain-specific differences.
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Affiliation(s)
| | - Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, Georgia
| | - Kameryn M Butler
- Department of Human Genetics, Emory University, Atlanta, Georgia
| | | | | | - Xuewen Wu
- Department of Cell Biology, Emory University, Atlanta, Georgia.,Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia
| | - Xi Lin
- Department of Cell Biology, Emory University, Atlanta, Georgia.,Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia
| | | | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, Georgia
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23
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Focken T, Burford K, Grimwood ME, Zenova A, Andrez JC, Gong W, Wilson M, Taron M, Decker S, Lofstrand V, Chowdhury S, Shuart N, Lin S, Goodchild SJ, Young C, Soriano M, Tari PK, Waldbrook M, Nelkenbrecher K, Kwan R, Lindgren A, de Boer G, Lee S, Sojo L, DeVita RJ, Cohen CJ, Wesolowski SS, Johnson JP, Dehnhardt CM, Empfield JR. Identification of CNS-Penetrant Aryl Sulfonamides as Isoform-Selective Na V1.6 Inhibitors with Efficacy in Mouse Models of Epilepsy. J Med Chem 2019; 62:9618-9641. [PMID: 31525968 DOI: 10.1021/acs.jmedchem.9b01032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nonselective antagonists of voltage-gated sodium (NaV) channels have been long used for the treatment of epilepsies. The efficacy of these drugs is thought to be due to the block of sodium channels on excitatory neurons, primarily NaV1.6 and NaV1.2. However, these currently marketed drugs require high drug exposure and suffer from narrow therapeutic indices. Selective inhibition of NaV1.6, while sparing NaV1.1, is anticipated to provide a more effective and better tolerated treatment for epilepsies. In addition, block of NaV1.2 may complement the anticonvulsant activity of NaV1.6 inhibition. We discovered a novel series of aryl sulfonamides as CNS-penetrant, isoform-selective NaV1.6 inhibitors, which also displayed potent block of NaV1.2. Optimization focused on increasing selectivity over NaV1.1, improving metabolic stability, reducing active efflux, and addressing a pregnane X-receptor liability. We obtained compounds 30-32, which produced potent anticonvulsant activity in mouse seizure models, including a direct current maximal electroshock seizure assay.
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Affiliation(s)
- Thilo Focken
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Kristen Burford
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Michael E Grimwood
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Alla Zenova
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Jean-Christophe Andrez
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Wei Gong
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Michael Wilson
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Matt Taron
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Shannon Decker
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Verner Lofstrand
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Sultan Chowdhury
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Noah Shuart
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Sophia Lin
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Samuel J Goodchild
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Clint Young
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Maegan Soriano
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Parisa K Tari
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Matthew Waldbrook
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Karen Nelkenbrecher
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Rainbow Kwan
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Andrea Lindgren
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Gina de Boer
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Stephanie Lee
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Luis Sojo
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Robert J DeVita
- RJD Medicinal Chemistry and Drug Discovery Consulting LLC , Westfield , New Jersey 07090 , United States
| | - Charles J Cohen
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Steven S Wesolowski
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - J P Johnson
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - Christoph M Dehnhardt
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
| | - James R Empfield
- Xenon Pharmaceuticals Inc. , 200-3650 Gilmore Way , Burnaby , British Columbia V5G 4W8 , Canada
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Saba L, Viscomi MT, Martini A, Caioli S, Mercuri NB, Guatteo E, Zona C. Modified age-dependent expression of NaV1.6 in an ALS model correlates with motor cortex excitability alterations. Neurobiol Dis 2019; 130:104532. [PMID: 31302244 DOI: 10.1016/j.nbd.2019.104532] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/28/2019] [Accepted: 07/10/2019] [Indexed: 12/13/2022] Open
Abstract
Cortical hyperexcitability is an early and intrinsic feature of Amyotrophic Lateral Sclerosis (ALS), but the mechanisms underlying this critical neuronal dysfunction are poorly understood. Recently, we have demonstrated that layer V pyramidal neurons (PNs) in the primary motor cortex (M1) of one-month old (P30) G93A ALS mice display an early hyperexcitability status compared to Control mice. In order to investigate the time-dependent evolution of the cortical excitability in the G93A ALS model, here we have performed an electrophysiological and immunohistochemical study at three different mouse ages. M1 PNs from 14-days old (P14) G93A mice have shown no excitability alterations, while M1 PNs from 3-months old (P90) G93A mice have shown a hypoexcitability status, compared to Control mice. These age-dependent cortical excitability dysfunctions correlate with a similar time-dependent trend of the persistent sodium current (INaP) amplitude alterations, suggesting that INaP may play a crucial role in the G93A cortical excitability aberrations. Specifically, immunohistochemistry experiments have indicated that the expression level of the NaV1.6 channel, one of the voltage-gated Na+ channels mainly distributed within the central nervous system, varies in G93A primary motor cortex during disease progression, according to the excitability and INaP alterations, but not in other cortical areas. Microfluorometry experiments, combined with electrophysiological recordings, have verified that P30 G93A PNs hyperexcitability is associated to a greater accumulation of intracellular calcium ([Ca2+]i) compared to Control PNs, and that this difference is still present when G93A and Control PNs fire action potentials at the same frequency. These results suggest that [Ca2+]i de-regulation in G93A PNs may contribute to neuronal demise and that the NaV1.6 channels could be a potential therapeutic target to ameliorate ALS disease progression.
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Affiliation(s)
- Luana Saba
- Department of Systems Medicine, University of Rome "Tor Vergata" via Montpellier 1, Rome 00133, Italy
| | - Maria Teresa Viscomi
- Università Cattolica del Sacro Cuore, Istituto di Istologia ed Embriologia, Fondazione Policlinico Universitario A. Gemelli, Largo F. Vito 1, Rome 00168, Italy
| | - Alessandro Martini
- IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy
| | - Silvia Caioli
- IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy
| | - Nicola Biagio Mercuri
- Department of Systems Medicine, University of Rome "Tor Vergata" via Montpellier 1, Rome 00133, Italy; IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy
| | - Ezia Guatteo
- IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy; Department of Motor Science and Wellness, University of Naples 'Parthenope', Via Medina 40, Naples 80133, Italy
| | - Cristina Zona
- Department of Systems Medicine, University of Rome "Tor Vergata" via Montpellier 1, Rome 00133, Italy; IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy.
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Abstract
Pharmaco-Genetic Therapeutics Targeting Parvalbumin Neurons Attenuate Temporal Lobe Epilepsy Wang Y, Liang J, Chen L, Shen Y, Zhao J, Xu C, Wu X, Cheng H, Ying X, Guo Y, Wang S, Zhou Y, Wang Y, Chen Z. Neurobiol Dis. 2018;117:149-60. Epub 2018/06/13. doi: 10.1016/j.nbd.2018.06.006. PubMed PMID: 29894753. Temporal lobe epilepsy (TLE) is the most common type of epilepsy and is often medically refractory. Previous studies suggest that selective pharmaco-genetic inhibition of pyramidal neurons has therapeutic value for the treatment of epilepsy; however, there is a risk of disrupting normal physical functions. Here, we test whether pharmaco-genetic activation of parvalbumin neurons, which are transgenetically transduced with the modified muscarinic receptor hM3Dq, can attenuate TLE. We found that pharmaco-genetic activation of hippocampal parvalbumin neurons in epileptogenic zone not only significantly extends the latency to different seizure stages and attenuates seizure activities in acute seizure model but also greatly alleviates the severity of seizure onsets in 2 chronic epilepsy models. This manipulation did not affect the normal physical function evaluated in various cognitive tasks. Further, the activation of parvalbumin neurons produced an inhibition on parts of surrounding pyramidal neurons, and the direct inactivation of pyramidal neurons via the viral expression of a modified muscarinic receptor hM4Di produced a similar anti-ictogenic effect. Interestingly, pharmacogenetic inactivation of pyramidal neurons was more sensitive to impair cognitive function. Those data demonstrated that pharmaco-genetic seizure attenuation through targeting parvalbumin neurons rather than pyramidal neurons may be a novel and relatively safe approach for treating refractory TLE.
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Bialer M, Johannessen SI, Koepp MJ, Levy RH, Perucca E, Tomson T, White HS. Progress report on new antiepileptic drugs: A summary of the Fourteenth Eilat Conference on New Antiepileptic Drugs and Devices (EILAT XIV). I. Drugs in preclinical and early clinical development. Epilepsia 2018; 59:1811-1841. [DOI: 10.1111/epi.14557] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/08/2018] [Accepted: 08/08/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Meir Bialer
- Faculty of Medicine; School of Pharmacy and David R. Bloom Center for Pharmacy; Institute for Drug Research; Hebrew University of Jerusalem; Jerusalem Israel
| | - Svein I. Johannessen
- National Center for Epilepsy; Sandvika Norway
- Department of Pharmacology; Oslo University Hospital; Oslo Norway
| | - Matthias J. Koepp
- Department of Clinical and Experimental Epilepsy; UCL Institute of Neurology; London UK
| | - René H. Levy
- Departments of Pharmaceutics and Neurological Surgery; University of Washington; Seattle Washington
| | - Emilio Perucca
- Department of Internal Medicine and Therapeutics; University of Pavia; Pavia Italy
- IRCCS Mondino Foundation; Pavia Italy
| | - Torbjörn Tomson
- Department of Clinical Neuroscience; Karolinska Institute; Stockholm Sweden
| | - H. Steve White
- Department of Pharmacy; School of Pharmacy; University of Washington; Seattle Washington
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