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Zhang Y, Wu J, Zheng Y, Xu Y, Yu Z, Ping Y. Voltage Gated Ion Channels and Sleep. J Membr Biol 2024:10.1007/s00232-024-00325-0. [PMID: 39354150 DOI: 10.1007/s00232-024-00325-0] [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: 07/31/2024] [Accepted: 09/24/2024] [Indexed: 10/03/2024]
Abstract
Ion channels are integral components of the nervous system, playing a pivotal role in shaping membrane potential, neuronal excitability, synaptic transmission and plasticity. Dysfunction in these channels, such as improper expression or localization, can lead to irregular neuronal excitability and synaptic communication, which may manifest as various behavioral abnormalities, including disrupted rest-activity cycles. Research has highlighted the significant impact of voltage gated ion channels on sleep parameters, influencing sleep latency, duration and waveforms. Furthermore, these ion channels have been implicated in the vulnerability to, and the pathogenesis of, several neurological and psychiatric disorders, including epilepsy, autism, schizophrenia, and Alzheimer's disease (AD). In this comprehensive review, we aim to provide a summary of the regulatory role of three predominant types of voltage-gated ion channels-calcium (Ca2+), sodium (Na+), and potassium (K+)-in sleep across species, from flies to mammals. We will also discuss the association of sleep disorders with various human diseases that may arise from the dysfunction of these ion channels, thereby underscoring the potential therapeutic benefits of targeting specific ion channel subtypes for sleep disturbance treatment.
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Affiliation(s)
- Yan Zhang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiawen Wu
- Faculty of Brain Sciences, University College London, London, UK
| | - Yuxian Zheng
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yangkun Xu
- Tandon School of Engineering, New York University, Brooklyn, NY, 11201, USA
| | - Ziqi Yu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yong Ping
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, 200240, China.
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2
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Potesta CV, Cargile MS, Yan A, Xiong S, Macdonald RL, Gallagher MJ, Zhou C. Preoptic area controls sleep-related seizure onset in a genetic epilepsy mouse model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.24.568593. [PMID: 39314442 PMCID: PMC11418963 DOI: 10.1101/2023.11.24.568593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
In genetic and refractory epileptic patients, seizure activity exhibits sleep-related modulation/regulation and sleep and seizure are intermingled. In this study, by using one het Gabrg2 Q390X KI mice as a genetic epilepsy model and optogenetic method in vivo, we found that subcortical POA neurons were active within epileptic network from the het Gabrg2 Q390X KI mice and the POA activity preceded epileptic (poly)spike-wave discharges(SWD/PSDs) in the het Gabrg2 Q390X KI mice. Meanwhile, as expected, the manipulating of the POA activity relatively altered NREM sleep and wake periods in both wt and the het Gabrg2 Q390X KI mice. Most importantly, the short activation of epileptic cortical neurons alone did not effectively trigger seizure activity in the het Gabrg2 Q390X KI mice. In contrast, compared to the wt mice, combined the POA nucleus activation and short activation of the epileptic cortical neurons effectively triggered or suppressed epileptic activity in the het Gabrg2 Q390X KI mice, indicating that the POA activity can control the brain state to trigger seizure incidence in the het Gabrg2 Q390X KI mice in vivo. In addition, the suppression of POA nucleus activity decreased myoclonic jerks in the Gabrg2 Q390X KI mice. Overall, this study discloses an operational mechanism for sleep-dependent seizure incidence in the genetic epilepsy model with the implications for refractory epilepsy. This operational mechanism also underlies myoclonic jerk generation, further with translational implications in seizure treatment for genetic/refractory epileptic patients and with contribution to memory/cognitive deficits in epileptic patients.
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Affiliation(s)
| | | | | | | | - Robert L. Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Martin J. Gallagher
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232
- Vanderbilt Brain Institute and Neuroscience graduate program, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232
- Vanderbilt Brain Institute and Neuroscience graduate program, Vanderbilt University Medical Center, Nashville, TN 37232
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3
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Medina E, Peterson S, Ford K, Singletary K, Peixoto L. Critical periods and Autism Spectrum Disorders, a role for sleep. Neurobiol Sleep Circadian Rhythms 2023; 14:100088. [PMID: 36632570 PMCID: PMC9826922 DOI: 10.1016/j.nbscr.2022.100088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Brain development relies on both experience and genetically defined programs. Time windows where certain brain circuits are particularly receptive to external stimuli, resulting in heightened plasticity, are referred to as "critical periods". Sleep is thought to be essential for normal brain development. Importantly, studies have shown that sleep enhances critical period plasticity and promotes experience-dependent synaptic pruning in the developing mammalian brain. Therefore, normal plasticity during critical periods depends on sleep. Problems falling and staying asleep occur at a higher rate in Autism Spectrum Disorder (ASD) relative to typical development. In this review, we explore the potential link between sleep, critical period plasticity, and ASD. First, we review the importance of critical period plasticity in typical development and the role of sleep in this process. Next, we summarize the evidence linking ASD with deficits in synaptic plasticity in rodent models of high-confidence ASD gene candidates. We then show that the high-confidence rodent models of ASD that show sleep deficits also display plasticity deficits. Given how important sleep is for critical period plasticity, it is essential to understand the connections between synaptic plasticity, sleep, and brain development in ASD. However, studies investigating sleep or plasticity during critical periods in ASD mouse models are lacking. Therefore, we highlight an urgent need to consider developmental trajectory in studies of sleep and plasticity in neurodevelopmental disorders.
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Affiliation(s)
- Elizabeth Medina
- Department of Translational Medicine and Physiology, Sleep and Performance Research Center, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, United States
| | - Sarah Peterson
- Department of Translational Medicine and Physiology, Sleep and Performance Research Center, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, United States
| | - Kaitlyn Ford
- Department of Translational Medicine and Physiology, Sleep and Performance Research Center, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, United States
| | - Kristan Singletary
- Department of Translational Medicine and Physiology, Sleep and Performance Research Center, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, United States
| | - Lucia Peixoto
- Department of Translational Medicine and Physiology, Sleep and Performance Research Center, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, United States
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4
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Moysés-Oliveira M, Paschalidis M, Souza-Cunha LA, Esteves-Guerreiro PA, Adami LNG, Kloster AK, Mosini AC, Moreira GA, Doria S, Tempaku PF, Pires GN, Andersen ML, Tufik S. Genetic basis of sleep phenotypes and rare neurodevelopmental syndromes reveal shared molecular pathways. J Neurosci Res 2023; 101:1058-1067. [PMID: 36791049 DOI: 10.1002/jnr.25180] [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: 11/10/2022] [Revised: 01/13/2023] [Accepted: 01/31/2023] [Indexed: 02/16/2023]
Abstract
Sleep-related phenotypes have been frequently reported in early on-set epileptic encephalopathies and in developmental delay syndromes, in particular in syndromes related to autism spectrum disorder. Yet the convergent pathogenetic mechanisms between these comorbidities are largely unknown. We first performed a gene enrichment study that identified shared risk genes among rare epileptic encephalopathies/neurodevelopmental disorders, rare developmental delay genetic syndromes and sleep disturbances. We then determined cellular and molecular pathways enriched among genes shared between sleep phenotypes and those two early onset mental illnesses, aiming to identify genetic disparities and commonalities among these phenotypic groups. The sleep gene set was observed as significantly overlapped with the two gene lists associated to rare genetic syndromes (i.e., epileptic encephalopathies/neurodevelopmental disorders and developmental delay gene sets), suggesting shared genetic contribution. Similarities across significantly enriched pathways between the two intersect lists comprehended mostly synapse-related pathways, such as retrograde endocannabinoid signaling, serotonergic, and GABAergic synapse. Network analysis indicates epileptic encephalopathies/neurodevelopmental disorders versus sleep-specific clusters and developmental delay versus sleep-specific clusters related to synaptic and transcriptional regulation, respectively. Longstanding functional patterns previously described in epileptic encephalopathies and neurodevelopmental disorders genetic architecture were recaptured after dissecting the overlap between the genes associated to those developmental phenotypes and sleep disturbances, suggesting that during neurodevelopment different molecular and functional mechanisms are related to alterations on circadian rhythm. The overlapping gene set and biological pathways highlighted by this study may serve as a primer for new functional investigations of shared molecular mechanisms between sleep disturbances and rare developmental syndromes.
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Affiliation(s)
| | | | | | | | | | | | | | - Gustavo A Moreira
- Sleep Institute, São Paulo, Brazil.,Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil.,Departamento de Pediatria, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Sandra Doria
- Sleep Institute, São Paulo, Brazil.,Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Priscila F Tempaku
- Sleep Institute, São Paulo, Brazil.,Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Gabriel N Pires
- Sleep Institute, São Paulo, Brazil.,Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Monica L Andersen
- Sleep Institute, São Paulo, Brazil.,Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Sergio Tufik
- Sleep Institute, São Paulo, Brazil.,Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
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5
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Grogan DP, Skelton HM, Fernandez AM, Gutekunst CANE, Gross RE. The laterodorsal tegmentum and seizure regulation: Revisiting the evidence. J Neurosci Res 2023; 101:256-262. [PMID: 36349730 DOI: 10.1002/jnr.25144] [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: 09/22/2022] [Accepted: 10/26/2022] [Indexed: 11/10/2022]
Abstract
Electrical deep brain stimulation (DBS) is now a routine treatment option for patients suffering from medically refractory epilepsy. DBS of the anterior nucleus of the thalamus (ANT) has proven to be effective but, despite its success, few patients experience complete cessation of seizure activity. However, improving the therapy is challenging because the mechanism underlying its action remains largely unknown. One angle on improving the effectiveness of ANT stimulation is to better understand the various anatomic regions that send projections to and through this area. Here, the authors utilized a connectomic atlas of the mouse brain to better understand the regions projecting to the ANT and were particularly interested by the presence of robust cholinergic projections from the laterodorsal tegmentum (LDT). A subsequent review of the literature resulted in limited studies, which presented convincing evidence supporting this region's role in seizure control present in acute rodent models of epilepsy. It is thus the purpose of this paper to encourage further research into the role of the LDT on seizure mitigation, with mechanistic effects likely stemming from its cholinergic projections to the ANT. While previous studies have laid a firm foundation supporting the role of this region in modulation of seizure activity, modern scientific methodology has yet to be applied to further elucidate the mechanisms and potential benefits associated with LDT stimulation in the epileptic population.
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Affiliation(s)
- Dayton P Grogan
- Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Henry M Skelton
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Alejandra M Fernandez
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | - Robert E Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA.,Department of Neurology, Emory University, Atlanta, Georgia, USA
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6
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Catron MA, Howe RK, Besing GLK, St. John EK, Potesta CV, Gallagher MJ, Macdonald RL, Zhou C. Sleep slow-wave oscillations trigger seizures in a genetic epilepsy model of Dravet syndrome. Brain Commun 2022; 5:fcac332. [PMID: 36632186 PMCID: PMC9830548 DOI: 10.1093/braincomms/fcac332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/09/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Sleep is the preferential period when epileptic spike-wave discharges appear in human epileptic patients, including genetic epileptic seizures such as Dravet syndrome with multiple mutations including SCN1A mutation and GABAA receptor γ2 subunit Gabrg2Q390X mutation in patients, which presents more severe epileptic symptoms in female patients than male patients. However, the seizure onset mechanism during sleep still remains unknown. Our previous work has shown that the sleep-like state-dependent homeostatic synaptic potentiation can trigger epileptic spike-wave discharges in one transgenic heterozygous Gabrg2+/Q390X knock-in mouse model.1 Here, using this heterozygous knock-in mouse model, we hypothesized that slow-wave oscillations themselves in vivo could trigger epileptic seizures. We found that epileptic spike-wave discharges in heterozygous Gabrg2+/Q390X knock-in mice exhibited preferential incidence during non-rapid eye movement sleep period, accompanied by motor immobility/facial myoclonus/vibrissal twitching and more frequent spike-wave discharge incidence appeared in female heterozygous knock-in mice than male heterozygous knock-in mice. Optogenetically induced slow-wave oscillations in vivo significantly increased epileptic spike-wave discharge incidence in heterozygous Gabrg2+/Q390X knock-in mice with longer duration of non-rapid eye movement sleep or quiet-wakeful states. Furthermore, suppression of slow-wave oscillation-related homeostatic synaptic potentiation by 4-(diethylamino)-benzaldehyde injection (i.p.) greatly attenuated spike-wave discharge incidence in heterozygous knock-in mice, suggesting that slow-wave oscillations in vivo did trigger seizure activity in heterozygous knock-in mice. Meanwhile, sleep spindle generation in wild-type littermates and heterozygous Gabrg2+/Q390X knock-in mice involved the slow-wave oscillation-related homeostatic synaptic potentiation that also contributed to epileptic spike-wave discharge generation in heterozygous Gabrg2+/Q390X knock-in mice. In addition, EEG spectral power of delta frequency (0.1-4 Hz) during non-rapid eye movement sleep was significantly larger in female heterozygous Gabrg2+/Q390X knock-in mice than that in male heterozygous Gabrg2+/Q390X knock-in mice, which likely contributes to the gender difference in seizure incidence during non-rapid eye movement sleep/quiet-wake states of human patients. Overall, all these results indicate that slow-wave oscillations in vivo trigger the seizure onset in heterozygous Gabrg2+/Q390X knock-in mice, preferentially during non-rapid eye movement sleep period and likely generate the sex difference in seizure incidence between male and female heterozygous Gabrg2+/Q390X knock-in mice.
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Affiliation(s)
- Mackenzie A Catron
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel K Howe
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Gai-Linn K Besing
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Emily K St. John
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - Martin J Gallagher
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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7
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Ma Z, Eaton M, Liu Y, Zhang J, Chen X, Tu X, Shi Y, Que Z, Wettschurack K, Zhang Z, Shi R, Chen Y, Kimbrough A, Lanman NA, Schust L, Huang Z, Yang Y. Deficiency of autism-related Scn2a gene in mice disrupts sleep patterns and circadian rhythms. Neurobiol Dis 2022; 168:105690. [PMID: 35301122 PMCID: PMC9018617 DOI: 10.1016/j.nbd.2022.105690] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 02/21/2022] [Accepted: 03/09/2022] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorder (ASD) affects ~2% of the population in the US, and monogenic forms of ASD often result in the most severe manifestation of the disorder. Recently, SCN2A has emerged as a leading gene associated with ASD, of which abnormal sleep pattern is a common comorbidity. SCN2A encodes the voltage-gated sodium channel NaV1.2. Predominantly expressed in the brain, NaV1.2 mediates the action potential firing of neurons. Clinical studies found that a large portion of children with SCN2A deficiency have sleep disorders, which severely impact the quality of life of affected individuals and their caregivers. The underlying mechanism of sleep disturbances related to NaV1.2 deficiency, however, is not known. Using a gene-trap Scn2a-deficient mouse model (Scn2atrap), we found that Scn2a deficiency results in increased wakefulness and reduced non-rapid-eye-movement (NREM) sleep. Brain region-specific Scn2a deficiency in the suprachiasmatic nucleus (SCN) containing region, which is involved in circadian rhythms, partially recapitulates the sleep disturbance phenotypes. At the cellular level, we found that Scn2a deficiency disrupted the firing pattern of spontaneously firing neurons in the SCN region. At the molecular level, RNA-sequencing analysis revealed differentially expressed genes in the circadian entrainment pathway including core clock genes Per1 and Per2. Performing a transcriptome-based compound discovery, we identified dexanabinol (HU-211), a putative glutamate receptor modulator, that can partially reverse the sleep disturbance in mice. Overall, our study reveals possible molecular and cellular mechanisms underlying Scn2a deficiency-related sleep disturbances, which may inform the development of potential pharmacogenetic interventions for the affected individuals.
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Affiliation(s)
- Zhixiong Ma
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China; Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Muriel Eaton
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Yushuang Liu
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Jingliang Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Xiaoling Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Xinyu Tu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yiqiang Shi
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Zhefu Que
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Kyle Wettschurack
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA
| | - Zaiyang Zhang
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Riyi Shi
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Yueyi Chen
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Adam Kimbrough
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Nadia A Lanman
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Leah Schust
- FamilieSCN2A Foundation, P.O. Box 82, East Longmeadow, MA 01028, USA
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China.
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy & Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47906, USA.
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8
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Studtmann C, Ladislav M, Topolski MA, Safari M, Swanger SA. NaV1.1 haploinsufficiency impairs glutamatergic and GABAergic neuron function in the thalamus. Neurobiol Dis 2022; 167:105672. [DOI: 10.1016/j.nbd.2022.105672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 02/08/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
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9
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Kaduskar B, Kushwah RBS, Auradkar A, Guichard A, Li M, Bennett JB, Julio AHF, Marshall JM, Montell C, Bier E. Reversing insecticide resistance with allelic-drive in Drosophila melanogaster. Nat Commun 2022; 13:291. [PMID: 35022402 PMCID: PMC8755802 DOI: 10.1038/s41467-021-27654-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 12/02/2021] [Indexed: 12/27/2022] Open
Abstract
A recurring target-site mutation identified in various pests and disease vectors alters the voltage gated sodium channel (vgsc) gene (often referred to as knockdown resistance or kdr) to confer resistance to commonly used insecticides, pyrethroids and DDT. The ubiquity of kdr mutations poses a major global threat to the continued use of insecticides as a means for vector control. In this study, we generate common kdr mutations in isogenic laboratory Drosophila strains using CRISPR/Cas9 editing. We identify differential sensitivities to permethrin and DDT versus deltamethrin among these mutants as well as contrasting physiological consequences of two different kdr mutations. Importantly, we apply a CRISPR-based allelic-drive to replace a resistant kdr mutation with a susceptible wild-type counterpart in population cages. This successful proof-of-principle opens-up numerous possibilities including targeted reversion of insecticide-resistant populations to a native susceptible state or replacement of malaria transmitting mosquitoes with those bearing naturally occurring parasite resistant alleles. Insecticide resistance (IR) poses a major global health challenge. Here, the authors generate common IR mutations in laboratory Drosophila strains and use a CRISPR-based allelic-drive to replace an IR allele with a susceptible wild-type counterpart, providing a potent new tool for vector control.
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Affiliation(s)
- Bhagyashree Kaduskar
- Tata Institute for Genetics and Society, Center at inStem, Bangalore, Karnataka, 560065, India.,Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA.,Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Raja Babu Singh Kushwah
- Tata Institute for Genetics and Society, Center at inStem, Bangalore, Karnataka, 560065, India.,Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA.,Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ankush Auradkar
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Annabel Guichard
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA.,Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Menglin Li
- Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA.,Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Jared B Bennett
- Biophysics Graduate Group, Division of Biological Sciences, College of Letters and Science, University of California, Berkeley, CA, 94720, USA
| | | | - John M Marshall
- Division of Biostatistics and Epidemiology - School of Public Health, University of California, Berkeley, CA, 94720, USA.,Innovative Genomics Institute, Berkeley, CA, 94720, USA
| | - Craig Montell
- Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA.,Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Ethan Bier
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA. .,Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA, 92093, USA.
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10
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Transfer of SCN1A to the brain of adolescent mouse model of Dravet syndrome improves epileptic, motor, and behavioral manifestations. MOLECULAR THERAPY-NUCLEIC ACIDS 2021; 25:585-602. [PMID: 34589280 PMCID: PMC8463324 DOI: 10.1016/j.omtn.2021.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/13/2021] [Indexed: 12/02/2022]
Abstract
Dravet syndrome is a genetic encephalopathy characterized by severe epilepsy combined with motor, cognitive, and behavioral abnormalities. Current antiepileptic drugs achieve only partial control of seizures and provide little benefit on the patient’s neurological development. In >80% of cases, the disease is caused by haploinsufficiency of the SCN1A gene, which encodes the alpha subunit of the Nav1.1 voltage-gated sodium channel. Novel therapies aim to restore SCN1A expression in order to address all disease manifestations. We provide evidence that a high-capacity adenoviral vector harboring the 6-kb SCN1A cDNA is feasible and able to express functional Nav1.1 in neurons. In vivo, the best biodistribution was observed after intracerebral injection in basal ganglia, cerebellum, and prefrontal cortex. SCN1A A1783V knockin mice received the vector at 5 weeks of age, when most neurological alterations were present. Animals were protected from sudden death, and the epileptic phenotype was attenuated. Improvement of motor performance and interaction with the environment was observed. In contrast, hyperactivity persisted, and the impact on cognitive tests was variable (success in novel object recognition and failure in Morris water maze tests). These results provide proof of concept for gene supplementation in Dravet syndrome and indicate new directions for improvement.
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11
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Buchanan GF, Gluckman BJ, Kalume FK, Lhatoo S, Maganti RK, Noebels JL, Simeone KA, Quigg MS, Pavlova MK. Proceedings of the Sleep and Epilepsy Workshop: Section 3 Mortality: Sleep, Night, and SUDEP. Epilepsy Curr 2021; 21:15357597211004556. [PMID: 33787378 PMCID: PMC8609595 DOI: 10.1177/15357597211004556] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy. Likely pathophysiological mechanisms include seizure-induced cardiac and respiratory dysregulation. A frequently identified feature in SUDEP cases is that they occur at night. This raises the question of a role for sleep state in regulating of SUDEP. An association with sleep has been identified in a number of studies with patients and in animal models. The focus of this section of the Sleep and Epilepsy Workshop was on identifying and understanding the role for sleep and time of day in the pathophysiology of SUDEP.
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Affiliation(s)
- Gordon F. Buchanan
- Department of Neurology and Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Department of Neurology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Bruce J. Gluckman
- Department of Engineering Science & Mechanics, Penn State University, University Park, PA, USA
- Department of Neurosurgery, Penn State University, University Park, PA, USA
- Department of Biomedical Engineering, Penn State University, University Park, PA, USA
| | - Franck K. Kalume
- Department of Neurological Surgery, University of Washington and Seattle Children’s Research Institute, Seattle, WA, USA
| | - Samden Lhatoo
- Department of Neurology, University of Texas McGovern Medical School, Houston, TX, USA
| | - Rama K. Maganti
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Jeffrey L. Noebels
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Kristina A. Simeone
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Mark S. Quigg
- Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Milena K. Pavlova
- Department of Neurology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
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12
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Mantegazza M, Cestèle S, Catterall WA. Sodium channelopathies of skeletal muscle and brain. Physiol Rev 2021; 101:1633-1689. [PMID: 33769100 DOI: 10.1152/physrev.00025.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium channels initiate action potentials in nerve, skeletal muscle, and other electrically excitable cells. Mutations in them cause a wide range of diseases. These channelopathy mutations affect every aspect of sodium channel function, including voltage sensing, voltage-dependent activation, ion conductance, fast and slow inactivation, and both biosynthesis and assembly. Mutations that cause different forms of periodic paralysis in skeletal muscle were discovered first and have provided a template for understanding structure, function, and pathophysiology at the molecular level. More recent work has revealed multiple sodium channelopathies in the brain. Here we review the well-characterized genetics and pathophysiology of the periodic paralyses of skeletal muscle and then use this information as a foundation for advancing our understanding of mutations in the structurally homologous α-subunits of brain sodium channels that cause epilepsy, migraine, autism, and related comorbidities. We include studies based on molecular and structural biology, cell biology and physiology, pharmacology, and mouse genetics. Our review reveals unexpected connections among these different types of sodium channelopathies.
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Affiliation(s)
- Massimo Mantegazza
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France
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13
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Impaired θ-γ Coupling Indicates Inhibitory Dysfunction and Seizure Risk in a Dravet Syndrome Mouse Model. J Neurosci 2020; 41:524-537. [PMID: 33234612 DOI: 10.1523/jneurosci.2132-20.2020] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/02/2020] [Accepted: 11/12/2020] [Indexed: 01/24/2023] Open
Abstract
Dravet syndrome (DS) is an epileptic encephalopathy that still lacks biomarkers for epileptogenesis and its treatment. Dysfunction of NaV1.1 sodium channels, which are chiefly expressed in inhibitory interneurons, explains the epileptic phenotype. Understanding the network effects of these cellular deficits may help predict epileptogenesis. Here, we studied θ-γ coupling as a potential marker for altered inhibitory functioning and epileptogenesis in a DS mouse model. We found that cortical θ-γ coupling was reduced in both male and female juvenile DS mice and persisted only if spontaneous seizures occurred. θ-γ Coupling was partly restored by cannabidiol (CBD). Locally disrupting NaV1.1 expression in the hippocampus or cortex yielded early attenuation of θ-γ coupling, which in the hippocampus associated with fast ripples, and which was replicated in a computational model when voltage-gated sodium currents were impaired in basket cells (BCs). Our results indicate attenuated θ-γ coupling as a promising early indicator of inhibitory dysfunction and seizure risk in DS.
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14
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Wong JC, Shapiro L, Thelin JT, Heaton EC, Zaman RU, D'Souza MJ, Murnane KS, Escayg A. Nanoparticle encapsulated oxytocin increases resistance to induced seizures and restores social behavior in Scn1a-derived epilepsy. Neurobiol Dis 2020; 147:105147. [PMID: 33189882 DOI: 10.1016/j.nbd.2020.105147] [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: 08/05/2020] [Revised: 10/14/2020] [Accepted: 10/23/2020] [Indexed: 02/06/2023] Open
Abstract
Oxytocin (OT) has broad effects in the brain and plays an important role in cognitive, social, and neuroendocrine function. OT has also been identified as potentially therapeutic in neuropsychiatric disorders such as autism and depression, which are often comorbid with epilepsy, raising the possibility that it might confer protection against the behavioral and seizure phenotypes in epilepsy. Dravet syndrome (DS) is an early-life encephalopathy associated with prolonged and recurrent early-life febrile seizures (FSs), treatment-resistant afebrile epilepsy, and cognitive and behavioral deficits. De novo loss-of-function mutations in the voltage-gated sodium channel SCN1A are the main cause of DS, while genetic epilepsy with febrile seizures plus (GEFS+), also characterized by early-life FSs and afebrile epilepsy, is typically caused by inherited mutations that alter the biophysical properties of SCN1A. Despite the wide range of available antiepileptic drugs, many patients with SCN1A mutations do not achieve adequate seizure control or the amelioration of associated behavioral comorbidities. In the current study, we demonstrate that nanoparticle encapsulation of OT conferred robust and sustained protection against induced seizures and restored more normal social behavior in a mouse model of Scn1a-derived epilepsy. These results demonstrate the ability of a nanotechnology formulation to significantly enhance the efficacy of OT. This approach will provide a general strategy to enhance the therapeutic potential of additional neuropeptides in epilepsy and other neurological disorders.
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Affiliation(s)
- Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, GA, United States of America.
| | - Lindsey Shapiro
- Department of Human Genetics, Emory University, Atlanta, GA, United States of America
| | - Jacquelyn T Thelin
- Department of Human Genetics, Emory University, Atlanta, GA, United States of America
| | - Elizabeth C Heaton
- Department of Human Genetics, Emory University, Atlanta, GA, United States of America
| | - Rokon U Zaman
- Department of Pharmaceutical Sciences, Mercer University, Atlanta, GA, United States of America
| | - Martin J D'Souza
- Department of Pharmaceutical Sciences, Mercer University, Atlanta, GA, United States of America
| | - Kevin S Murnane
- Department of Pharmaceutical Sciences, Mercer University, Atlanta, GA, United States of America
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA, United States of America
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15
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The role of chronobiology in drug-resistance epilepsy: The potential use of a variability and chronotherapy-based individualized platform for improving the response to anti-seizure drugs. Seizure 2020; 80:201-211. [DOI: 10.1016/j.seizure.2020.06.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/27/2020] [Accepted: 06/30/2020] [Indexed: 12/16/2022] Open
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16
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Wintler T, Schoch H, Frank M, Peixoto L. Sleep, brain development, and autism spectrum disorders: Insights from animal models. J Neurosci Res 2020; 98:1137-1149. [PMID: 32215963 PMCID: PMC7199437 DOI: 10.1002/jnr.24619] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/07/2020] [Accepted: 02/29/2020] [Indexed: 01/28/2023]
Abstract
Sleep is an evolutionarily conserved and powerful drive, although its complete functions are still unknown. One possible function of sleep is that it promotes brain development. The amount of sleep is greatest during ages when the brain is rapidly developing, and sleep has been shown to influence critical period plasticity. This supports a role for sleep in brain development and suggests that abnormal sleep in early life may lead to abnormal development. Autism spectrum disorder (ASD) is the most prevalent neurodevelopmental disorder in the United States. It is estimated that insomnia affects 44%-86% of the ASD population, predicting the severity of ASD core symptoms and associated behavioral problems. Sleep problems impact the quality of life of both ASD individuals and their caregivers, thus it is important to understand why they are so prevalent. In this review, we explore the role of sleep in early life as a causal factor in ASD. First, we review fundamental steps in mammalian sleep ontogeny and regulation and how sleep influences brain development. Next, we summarize current knowledge gained from studying sleep in animal models of ASD. Ultimately, our goal is to highlight the importance of understanding the role of sleep in brain development and the use of animal models to provide mechanistic insight into the origin of sleep problems in ASD.
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Affiliation(s)
- Taylor Wintler
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
| | - Hannah Schoch
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
| | - Marcos Frank
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
| | - Lucia Peixoto
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
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17
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Sanchez REA, Bussi IL, Ben-Hamo M, Caldart CS, Catterall WA, De La Iglesia HO. Circadian regulation of sleep in a pre-clinical model of Dravet syndrome: dynamics of sleep stage and siesta re-entrainment. Sleep 2020; 42:5539047. [PMID: 31346614 DOI: 10.1093/sleep/zsz173] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/24/2019] [Indexed: 12/11/2022] Open
Abstract
STUDY OBJECTIVES Sleep disturbances are common co-morbidities of epileptic disorders. Dravet syndrome (DS) is an intractable epilepsy accompanied by disturbed sleep. While there is evidence that daily sleep timing is disrupted in DS, the difficulty of chronically recording polysomnographic sleep from patients has left our understanding of the effect of DS on circadian sleep regulation incomplete. We aim to characterize circadian sleep regulation in a mouse model of DS. METHODS Here we exploit long-term electrocorticographic recordings of sleep in a mouse model of DS in which one copy of the Scn1a gene is deleted. This model both genocopies and phenocopies the disease in humans. We test the hypothesis that the deletion of Scn1a in DS mice is associated with impaired circadian regulation of sleep. RESULTS We find that DS mice show impairments in circadian sleep regulation, including a fragmented rhythm of non-rapid eye movement (NREM) sleep and an elongated circadian period of sleep. Next, we characterize re-entrainment of sleep stages and siesta following jet lag in the mouse. Strikingly, we find that re-entrainment of sleep following jet lag is normal in DS mice, in contrast to previous demonstrations of slowed re-entrainment of wheel-running activity. Finally, we report that DS mice are more likely to have an absent or altered daily "siesta". CONCLUSIONS Our findings support the hypothesis that the circadian regulation of sleep is altered in DS and highlight the value of long-term chronic polysomnographic recording in studying the role of the circadian clock on sleep/wake cycles in pre-clinical models of disease.
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Affiliation(s)
- Raymond E A Sanchez
- Department of Biology, University of Washington, Seattle, WA.,Graduate Program in Neuroscience, University of Washington, Seattle WA
| | - Ivana L Bussi
- Department of Biology, University of Washington, Seattle, WA
| | - Miriam Ben-Hamo
- Department of Biology, University of Washington, Seattle, WA
| | | | - William A Catterall
- Graduate Program in Neuroscience, University of Washington, Seattle WA.,Department of Pharmacology, University of Washington, Seattle WA
| | - Horacio O De La Iglesia
- Department of Biology, University of Washington, Seattle, WA.,Graduate Program in Neuroscience, University of Washington, Seattle WA
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18
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Noebels JL. Predicting the impact of sodium channel mutations in human brain disease. Epilepsia 2020; 60 Suppl 3:S8-S16. [PMID: 31904123 PMCID: PMC6953257 DOI: 10.1111/epi.14724] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/15/2019] [Accepted: 03/18/2019] [Indexed: 12/21/2022]
Abstract
Genetic alteration of the sodium channel provides a remarkable opportunity to understand how epilepsy and its comorbidities arise from a molecular disease of excitable membranes, and a chance to create a better future for children with epileptic encephalopathy. In a single cell, the channel reliably acts as a voltage-sensitive switch, enabling axon impulse firing, whereas at a network level, it becomes a variable rheostat for regulating dynamic patterns of neuronal oscillations, including those underlying cognitive development, seizures, and even premature lethality. Despite steady progress linking genetic variation of the channels with distinctive clinical syndromes, our understanding of the intervening biologic complexity underlying each of them is only just beginning. More research on the functional contribution of individual channel subunits to specific brain networks and cellular plasticity in the developing brain is needed before we can reliably advance from precision diagnosis to precision treatment of inherited sodium channel disorders.
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Affiliation(s)
- Jeffrey L Noebels
- Blue Bird Circle Developmental Neurogenetics Laboratory, Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
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19
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Mantegazza M, Broccoli V. SCN1A/Na V 1.1 channelopathies: Mechanisms in expression systems, animal models, and human iPSC models. Epilepsia 2020; 60 Suppl 3:S25-S38. [PMID: 31904127 DOI: 10.1111/epi.14700] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 03/04/2019] [Indexed: 12/20/2022]
Abstract
Pathogenic SCN1A/NaV 1.1 mutations cause well-defined epilepsies, including genetic epilepsy with febrile seizures plus (GEFS+) and the severe epileptic encephalopathy Dravet syndrome. In addition, they cause a severe form of migraine with aura, familial hemiplegic migraine. Moreover, SCN1A/NaV 1.1 variants have been inferred as risk factors in other types of epilepsy. We review here the advancements obtained studying pathologic mechanisms of SCN1A/NaV 1.1 mutations with experimental systems. We present results gained with in vitro expression systems, gene-targeted animal models, and the induced pluripotent stem cell (iPSC) technology, highlighting advantages, limits, and pitfalls for each of these systems. Overall, the results obtained in the last two decades confirm that the initial pathologic mechanism of epileptogenic SCN1A/NaV 1.1 mutations is loss-of-function of NaV 1.1 leading to hypoexcitability of at least some types of γ-aminobutyric acid (GABA)ergic neurons (including cortical and hippocampal parvalbumin-positive and somatostatin-positive ones). Conversely, more limited results point to NaV 1.1 gain-of-function for familial hemiplegic migraine (FHM) mutations. Behind these relatively simple pathologic mechanisms, an unexpected complexity has been observed, in part generated by technical issues in experimental studies and in part related to intrinsically complex pathophysiologic responses and remodeling, which yet remain to be fully disentangled.
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Affiliation(s)
- Massimo Mantegazza
- University Cote d'Azur (UCA), CNRS UMR7275, INSERM, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Vania Broccoli
- San Raffaele Scientific Institute, Milan, Italy.,Institute of Neuroscience, National Research Council (CNR), Milan, Italy
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20
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Ritter-Makinson S, Clemente-Perez A, Higashikubo B, Cho FS, Holden SS, Bennett E, Chkhaidze A, Eelkman Rooda OHJ, Cornet MC, Hoebeek FE, Yamakawa K, Cilio MR, Delord B, Paz JT. Augmented Reticular Thalamic Bursting and Seizures in Scn1a-Dravet Syndrome. Cell Rep 2020; 26:54-64.e6. [PMID: 30605686 PMCID: PMC6555418 DOI: 10.1016/j.celrep.2018.12.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/07/2018] [Accepted: 12/03/2018] [Indexed: 11/26/2022] Open
Abstract
Loss of function in the Scn1a gene leads to a severe epileptic encephalopathy called Dravet syndrome (DS). Reduced excitability in cortical inhibitory neurons is thought to be the major cause of DS seizures. Here, in contrast, we show enhanced excitability in thalamic inhibitory neurons that promotes the non-convulsive seizures that are a prominent yet poorly understood feature of DS. In a mouse model of DS with a loss of function in Scn1a, reticular thalamic cells exhibited abnormally long bursts of firing caused by the downregulation of calcium-activated potassium SK channels. Our study supports a mechanism in which loss of SK activity causes the reticular thalamic neurons to become hyperexcitable and promote non-convulsive seizures in DS. We propose that reduced excitability of inhibitory neurons is not global in DS and that non-GABAergic mechanisms such as SK channels may be important targets for treatment. In a mouse model of Dravet syndrome (DS) resulting from voltage-gated sodium channel deficiency, Ritter-Makinson et al. find that inhibitory neurons of the reticular thalamic nucleus are paradoxically hyperexcitable due to compensatory reductions in a potassium SK current. Boosting this SK current treats nonconvulsive seizures in DS mice.
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Affiliation(s)
- Stefanie Ritter-Makinson
- Gladstone Institute of Neurological Disease, San Francisco, San Francisco, CA 94158, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alexandra Clemente-Perez
- Gladstone Institute of Neurological Disease, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA; Neurosciences Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Bryan Higashikubo
- Gladstone Institute of Neurological Disease, San Francisco, San Francisco, CA 94158, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Frances S Cho
- Gladstone Institute of Neurological Disease, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA; Neurosciences Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Stephanie S Holden
- Gladstone Institute of Neurological Disease, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA; Neurosciences Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Eric Bennett
- Gladstone Institute of Neurological Disease, San Francisco, San Francisco, CA 94158, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Ana Chkhaidze
- Gladstone Institute of Neurological Disease, San Francisco, San Francisco, CA 94158, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Oscar H J Eelkman Rooda
- Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands; Department of Neurosurgery, Erasmus MC, Rotterdam, the Netherlands
| | - Marie-Coralie Cornet
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Pediatrics, Catholic University of Louvain, Louvain, Belgium
| | - Freek E Hoebeek
- Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands; Department of Neurosurgery, Erasmus MC, Rotterdam, the Netherlands; NIDOD Institute, Wilhelmina Children's Hospital, University Medical Center Utrecht and Brain Center Rudolf Magnus, Utrecht, the Netherlands
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, Wako, Japan
| | - Maria Roberta Cilio
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Bruno Delord
- Institut des Systèmes Intelligents et de Robotique (ISIR), Sorbonne University, 4 Place Jussieu, 75005 Paris, France
| | - Jeanne T Paz
- Gladstone Institute of Neurological Disease, San Francisco, San Francisco, CA 94158, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA; Neurosciences Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA.
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21
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Schoonjans AS, De Keersmaecker S, Van Bouwel M, Ceulemans B. More daytime sleepiness and worse quality of sleep in patients with Dravet Syndrome compared to other epilepsy patients. Eur J Paediatr Neurol 2019; 23:61-69. [PMID: 30340858 DOI: 10.1016/j.ejpn.2018.09.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 09/13/2018] [Accepted: 09/23/2018] [Indexed: 01/15/2023]
Abstract
AIM Sleep problems are often reported in patients with a Dravet Syndrome (DS). In this study we explored the sleep behavior in DS and compared the prevalence of sleep problems with other epilepsy patients. METHODS An online questionnaire based on the 'Sleep Behavior Questionnaire by Simonds & Parraga (SQ-SP)' was distributed amongst DS parents and a control group (parents from children with epilepsy). Completed questionnaires were evaluated by factor scores and Composite Sleep Index (CSI). RESULTS Fifty-six responses were recorded in the DS group (42 were ≤18 year). Caregivers reported an overall frequency of sleep problems in 42.3% (22/52). Severe sleep problems, measured by CSI, were found in 28.3% (13/46) mainly related to night waking or daytime sleepiness. In the control group (n = 66, 62 were ≤18 year), sleep problems were reported by 21.2% (14/52) of the parents. Comparison analysis between pediatric DS and epilepsy patients revealed no significant differences between the prevalence of different types of sleep disorders, except for daytime sleepiness (p = 0.042). However, the parent (or caregiver)-reported quality of sleep was significantly lower in the DS group (p = 0.011). INTERPRETATION Sleep problems are frequent in DS patients and are mainly related to daytime sleepiness and night waking. Compared with other epilepsy patients, severe sleep problems are not more common in patients with a DS. However DS patients tend to have more mild night waking problems, which may explain the worse parental-reported sleep quality in DS patients.
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Affiliation(s)
- An-Sofie Schoonjans
- Department of Pediatric Neurology, Antwerp University Hospital, University of Antwerp, Belgium.
| | | | - Maxime Van Bouwel
- Faculty of Medicine and Health Sciences, Antwerp University Hospital, Antwerp, Belgium
| | - Berten Ceulemans
- Department of Pediatric Neurology, Antwerp University Hospital, University of Antwerp, Belgium
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22
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Griffin A, Hamling KR, Hong S, Anvar M, Lee LP, Baraban SC. Preclinical Animal Models for Dravet Syndrome: Seizure Phenotypes, Comorbidities and Drug Screening. Front Pharmacol 2018; 9:573. [PMID: 29915537 PMCID: PMC5994396 DOI: 10.3389/fphar.2018.00573] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/14/2018] [Indexed: 12/18/2022] Open
Abstract
Epilepsy is a common chronic neurological disease affecting almost 3 million people in the United States and 50 million people worldwide. Despite availability of more than two dozen FDA-approved anti-epileptic drugs (AEDs), one-third of patients fail to receive adequate seizure control. Specifically, pediatric genetic epilepsies are often the most severe, debilitating and pharmaco-resistant forms of epilepsy. Epileptic syndromes share a common symptom of unprovoked seizures. While some epilepsies/forms of epilepsy are the result of acquired insults such as head trauma, febrile seizure, or viral infection, others have a genetic basis. The discovery of epilepsy associated genes suggests varied underlying pathologies and opens the door for development of new "personalized" treatment options for each genetic epilepsy. Among these, Dravet syndrome (DS) has received substantial attention for both the pre-clinical and early clinical development of novel therapeutics. Despite these advances, there is no FDA-approved treatment for DS. Over 80% of patients diagnosed with DS carry a de novo mutation within the voltage-gated sodium channel gene SCN1A and these patients suffer with drug resistant and life-threatening seizures. Here we will review the preclinical animal models for DS featuring inactivation of SCN1A (including zebrafish and mice) with an emphasis on seizure phenotypes and behavioral comorbidities. Because many drugs fail somewhere between initial preclinical discovery and clinical trials, it is equally important that we understand how these models respond to known AEDs. As such, we will also review the available literature and recent drug screening efforts using these models with a focus on assay protocols and predictive pharmacological profiles. Validation of these preclinical models is a critical step in our efforts to efficiently discover new therapies for these patients. The behavioral and electrophysiological drug screening assays in zebrafish will be discussed in detail including specific examples from our laboratory using a zebrafish scn1 mutant and a summary of the nearly 3000 drugs screened to date. As the discovery and development phase rapidly moves from the lab-to-the-clinic for DS, it is hoped that this preclinical strategy offers a platform for how to approach any genetic epilepsy.
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Affiliation(s)
- Aliesha Griffin
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - Kyla R Hamling
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - SoonGweon Hong
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Mana Anvar
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - Luke P Lee
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Scott C Baraban
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
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23
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Licheni SH, Mcmahon JM, Schneider AL, Davey MJ, Scheffer IE. Sleep problems in Dravet syndrome: a modifiable comorbidity. Dev Med Child Neurol 2018; 60:192-198. [PMID: 29110313 DOI: 10.1111/dmcn.13601] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/28/2017] [Indexed: 01/08/2023]
Abstract
AIM Many children with severe developmental and epileptic encephalopathies experience significant sleep disturbance, causing major disruption to the family's quality of life. We aimed to determine the frequency and nature of sleep problems in individuals with Dravet syndrome. METHODS The Sleep Disturbance Scale for Children and a seizure questionnaire were distributed to the parents/guardians of 96 patients with Dravet syndrome. Sixteen patients had two nights of home oximetry. RESULTS Fifty-seven out of 96 questionnaires were completed. Forty-three out of 57 (75%) individuals had sleep problems. Twenty-five out of 57 (44%) individuals had an abnormal total sleep score, with difficulty initiating and maintaining sleep (22 out of 57, 39%), sleep-wake transition disorders (20 out of 57, 35%), and sleep breathing disorders (19 out of 57, 33%). Twenty-two out of 57 (39%) individuals took medication to assist sleep, predominantly melatonin (n=14). Thirty out of 57 (53%) recently had nocturnal seizures. Overnight oximetry showed 14 out of 16 (88%) had a higher oxygen desaturation index (>3%), and six out of 16 (38%) had higher mean pulse rates than normative values. Home oximetry was normal or inconclusive in all patients. INTERPRETATION Seventy-five per cent of individuals with Dravet syndrome had sleep problems, highlighting the importance of routinely assessing sleep and initiating appropriate behavioural and pharmacological interventions to improve the patient and family's quality of life. A high oxygen desaturation index and mean pulse rates on pulse oximetry may reflect unrecognized nocturnal seizures. WHAT THIS PAPER ADDS More than 70% of patients with Dravet syndrome have sleep problems. Difficulty initiating and maintaining sleep was most common, particularly in those older than 20 years. Second most common were sleep-wake transition disorders, affecting more than 50% of those younger than 5 years. Sleep breathing disorders were a frequent problem across all age groups. Oximetry was not diagnostic of sleep-disordered breathing or obvious seizures.
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Affiliation(s)
- Shane H Licheni
- Department of Medicine, Austin Health, University of Melbourne, Melbourne, Australia
| | - Jacinta M Mcmahon
- Department of Medicine, Austin Health, University of Melbourne, Melbourne, Australia
| | - Amy L Schneider
- Department of Medicine, Austin Health, University of Melbourne, Melbourne, Australia
| | - Margot J Davey
- Melbourne Children's Sleep Centre, Monash Children's Hospital, Melbourne, Australia
| | - Ingrid E Scheffer
- Department of Medicine, Austin Health, University of Melbourne, Melbourne, Australia.,Florey Institute of Neuroscience and Mental Health, Melbourne, Australia.,Department of Neurology and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia
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Wong JC, Makinson CD, Lamar T, Cheng Q, Wingard JC, Terwilliger EF, Escayg A. Selective targeting of Scn8a prevents seizure development in a mouse model of mesial temporal lobe epilepsy. Sci Rep 2018; 8:126. [PMID: 29317669 PMCID: PMC5760706 DOI: 10.1038/s41598-017-17786-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/30/2017] [Indexed: 11/08/2022] Open
Abstract
We previously found that genetic mutants with reduced expression or activity of Scn8a are resistant to induced seizures and that co-segregation of a mutant Scn8a allele can increase survival and seizure resistance of Scn1a mutant mice. In contrast, Scn8a expression is increased in the hippocampus following status epilepticus and amygdala kindling. These findings point to Scn8a as a promising therapeutic target for epilepsy and raise the possibility that aberrant overexpression of Scn8a in limbic structures may contribute to some epilepsies, including temporal lobe epilepsy. Using a small-hairpin-interfering RNA directed against the Scn8a gene, we selectively reduced Scn8a expression in the hippocampus of the intrahippocampal kainic acid (KA) mouse model of mesial temporal lobe epilepsy. We found that Scn8a knockdown prevented the development of spontaneous seizures in 9/10 mice, ameliorated KA-induced hyperactivity, and reduced reactive gliosis. These results support the potential of selectively targeting Scn8a for the treatment of refractory epilepsy.
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Affiliation(s)
- Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, Georgia, 30322, USA
| | | | - Tyra Lamar
- Department of Human Genetics, Emory University, Atlanta, Georgia, 30322, USA
| | - Qi Cheng
- Department of Human Genetics, Emory University, Atlanta, Georgia, 30322, USA
| | - Jeffrey C Wingard
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Ernest F Terwilliger
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, Georgia, 30322, USA.
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Iyer SH, Matthews SA, Simeone TA, Maganti R, Simeone KA. Accumulation of rest deficiency precedes sudden death of epileptic Kv1.1 knockout mice, a model of sudden unexpected death in epilepsy. Epilepsia 2017; 59:92-105. [PMID: 29193044 DOI: 10.1111/epi.13953] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2017] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Chronic sleep deficiency is associated with early mortality. In the epileptic population, there is a higher prevalence of sleep disorders, and individuals with severe refractory epilepsy are at greater risk of premature mortality than the general population. Sudden unexpected death in epilepsy affects 1:1000 cases of epilepsy each year. Ketogenic diet (KD) treatment is one of the few effective options for refractory seizures. Despite KD reducing seizures and increasing longevity in Kv1.1 knockout (KO) mice, they still succumb to sudden death. This study aims to determine whether (1) the rest profiles of KO and KD-treated KO (KOKD) mice resemble each other as a function of either age or proximity to death and (2) the timing of death correlates with acute or chronic changes in rest. METHODS Noninvasive actimetry was used to monitor rest throughout the lives of KO and wild-type (WT) littermates administered standard diet or KD. RESULTS As KO mice age, rest is reduced (P < .0001). Rest is significantly improved in KDKO mice (P < .0001), resembling WT values at several ages. When age is removed as a variable and data are realigned to the day of death, the rest profiles of KO and KOKD groups worsen to similar degrees as a function of proximity to death. The amount of rest acutely is not sensitive to the timing of death, whereas chronic rest deficiency profiles (10-15 days prior to death) of both groups were indistinguishable. Chronic accumulation of rest deficiency over the final 15 days was associated with 75% of deaths. SIGNIFICANCE Our data suggest that the accumulated rest deficiency is associated with sudden death in Kv1.1 KO mice. These data (1) support the proposed clinical hypothesis that chronic sleep deficiency may be associated with early mortality in epileptic patients and (2) warrant future preclinical and clinical studies on sleep monitoring in epileptic patients.
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Affiliation(s)
- Shruthi H Iyer
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Stephanie A Matthews
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Timothy A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Rama Maganti
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Kristina A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
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26
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Knupp KG, Scarbro S, Wilkening G, Juarez-Colunga E, Kempe A, Dempsey A. Parental Perception of Comorbidities in Children With Dravet Syndrome. Pediatr Neurol 2017; 76:60-65. [PMID: 28982531 DOI: 10.1016/j.pediatrneurol.2017.06.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 06/08/2017] [Accepted: 06/17/2017] [Indexed: 01/05/2023]
Abstract
BACKGROUND We hypothesized that children with Dravet syndrome may have additional common features beyond seizures and cognitive impairment. To address this gap in knowledge, we conducted a survey of caregivers of children with Dravet syndrome to identify and quantify their perception of associated symptoms in this population. METHODS An electronic survey was developed in REDcap (Research Electronic Data Capture) and sent via e-mail to the participants on the Dravet Syndrome Foundation e-mail list. Questions focused on eating, sleep, behavior, and other symptoms that might be related to Dravet syndrome. The questions were assessed using a four-point Likert scale (e.g., strongly agree to strongly disagree). Results were later dichotomized for analysis. Logistic regression was used to calculate odds ratios of various demographic factors potentially associated with symptoms. Multivariable models were constructed using backward elimination to assess the relationship among a variety of symptoms. RESULTS There were 202 respondents, 96% were parents of a child with Dravet syndrome (the remainder were grandparents or guardians); 90.5% were female. The median age of the affected child was eight years (interquartile range five to 14), 50% were male, and 90.5% were reported to have a known SCN1A mutation. At least one symptom associated with appetite was reported in 99% of respondents, 82% reported a disturbance of sleep, one third reported autonomic symptoms, and 75% reported problems with gait. Inattention and perseveration were reported more commonly than other behavioral disturbances. SIGNIFICANCE Caregivers have the perception of many symptoms in children with Dravet syndrome in addition to those that have been previously reported, including appetite, sleep, gait, and behavior. Many of these can significantly affect quality of life for both the child and the caregiver.
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Affiliation(s)
- Kelly G Knupp
- Department of Pediatrics and Neurology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado; ACCORDS (Adult and Child Consortium for Health Outcomes Research and Delivery Science), University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado.
| | - Sharon Scarbro
- ACCORDS (Adult and Child Consortium for Health Outcomes Research and Delivery Science), University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado; Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Greta Wilkening
- Department of Pediatrics and Neurology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Elizabeth Juarez-Colunga
- ACCORDS (Adult and Child Consortium for Health Outcomes Research and Delivery Science), University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado; Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Allison Kempe
- ACCORDS (Adult and Child Consortium for Health Outcomes Research and Delivery Science), University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado; Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Amanda Dempsey
- ACCORDS (Adult and Child Consortium for Health Outcomes Research and Delivery Science), University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado; Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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Behavioral Comorbidities and Drug Treatments in a Zebrafish scn1lab Model of Dravet Syndrome. eNeuro 2017; 4:eN-NWR-0066-17. [PMID: 28812061 PMCID: PMC5555352 DOI: 10.1523/eneuro.0066-17.2017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/11/2017] [Accepted: 07/30/2017] [Indexed: 12/15/2022] Open
Abstract
Loss-of-function mutations in SCN1A cause Dravet syndrome (DS), a catastrophic childhood epilepsy in which patients experience comorbid behavioral conditions, including movement disorders, sleep abnormalities, anxiety, and intellectual disability. To study the functional consequences of voltage-gated sodium channel mutations, we use zebrafish with a loss-of-function mutation in scn1lab, a zebrafish homolog of human SCN1A. Homozygous scn1labs552/s552 mutants exhibit early-life seizures, metabolic deficits, and early death. Here, we developed in vivo assays using scn1labs552 mutants between 3 and 6 d postfertilization (dpf). To evaluate sleep disturbances, we monitored larvae for 24 h with locomotion tracking software. Locomotor activity during dark (night phase) was significantly higher in mutants than in controls. Among anticonvulsant drugs, clemizole and diazepam, but not trazodone or valproic acid, decreased distance moved at night for scn1labs552 mutant larvae. To monitor exploratory behavior in an open field, we tracked larvae in a novel arena. Mutant larvae exhibited impaired exploratory behavior, with increased time spent near the edge of the arena and decreased mobility, suggesting greater anxiety. Both clemizole and diazepam, but not trazodone or valproic acid, decreased distance moved and increased time spent in the center of the arena. Counting inhibitory neurons in vivo revealed no differences between scn1labs552 mutants and siblings. Taken together, our results demonstrate conserved features of sleep, anxiety, and movement disorders in scn1lab mutant zebrafish, and provide evidence that a zebrafish model allows effective tests of treatments for behavioral comorbidities associated with DS.
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Makinson CD, Tanaka BS, Sorokin JM, Wong JC, Christian CA, Goldin AL, Escayg A, Huguenard JR. Regulation of Thalamic and Cortical Network Synchrony by Scn8a. Neuron 2017; 93:1165-1179.e6. [PMID: 28238546 DOI: 10.1016/j.neuron.2017.01.031] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/30/2016] [Accepted: 01/30/2017] [Indexed: 12/22/2022]
Abstract
Voltage-gated sodium channel (VGSC) mutations cause severe epilepsies marked by intermittent, pathological hypersynchronous brain states. Here we present two mechanisms that help to explain how mutations in one VGSC gene, Scn8a, contribute to two distinct seizure phenotypes: (1) hypoexcitation of cortical circuits leading to convulsive seizure resistance, and (2) hyperexcitation of thalamocortical circuits leading to non-convulsive absence epilepsy. We found that loss of Scn8a leads to altered RT cell intrinsic excitability and a failure in recurrent RT synaptic inhibition. We propose that these deficits cooperate to enhance thalamocortical network synchrony and generate pathological oscillations. To our knowledge, this finding is the first clear demonstration of a pathological state tied to disruption of the RT-RT synapse. Our observation that loss of a single gene in the thalamus of an adult wild-type animal is sufficient to cause spike-wave discharges is striking and represents an example of absence epilepsy of thalamic origin.
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Affiliation(s)
- Christopher D Makinson
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304, USA
| | - Brian S Tanaka
- Departments of Microbiology and Molecular Genetics and Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA
| | - Jordan M Sorokin
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304, USA
| | - Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - Catherine A Christian
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304, USA
| | - Alan L Goldin
- Departments of Microbiology and Molecular Genetics and Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA.
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304, USA.
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Lamar T, Vanoye CG, Calhoun J, Wong JC, Dutton SBB, Jorge BS, Velinov M, Escayg A, Kearney JA. SCN3A deficiency associated with increased seizure susceptibility. Neurobiol Dis 2017; 102:38-48. [PMID: 28235671 DOI: 10.1016/j.nbd.2017.02.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 01/24/2017] [Accepted: 02/20/2017] [Indexed: 11/25/2022] Open
Abstract
Mutations in voltage-gated sodium channels expressed highly in the brain (SCN1A, SCN2A, SCN3A, and SCN8A) are responsible for an increasing number of epilepsy syndromes. In particular, mutations in the SCN3A gene, encoding the pore-forming Nav1.3 α subunit, have been identified in patients with focal epilepsy. Biophysical characterization of epilepsy-associated SCN3A variants suggests that both gain- and loss-of-function SCN3A mutations may lead to increased seizure susceptibility. In this report, we identified a novel SCN3A variant (L247P) by whole exome sequencing of a child with focal epilepsy, developmental delay, and autonomic nervous system dysfunction. Voltage clamp analysis showed no detectable sodium current in a heterologous expression system expressing the SCN3A-L247P variant. Furthermore, cell surface biotinylation demonstrated a reduction in the amount of SCN3A-L247P at the cell surface, suggesting the SCN3A-L247P variant is a trafficking-deficient mutant. To further explore the possible clinical consequences of reduced SCN3A activity, we investigated the effect of a hypomorphic Scn3a allele (Scn3aHyp) on seizure susceptibility and behavior using a gene trap mouse line. Heterozygous Scn3a mutant mice (Scn3a+/Hyp) did not exhibit spontaneous seizures nor were they susceptible to hyperthermia-induced seizures. However, they displayed increased susceptibility to electroconvulsive (6Hz) and chemiconvulsive (flurothyl and kainic acid) induced seizures. Scn3a+/Hyp mice also exhibited deficits in locomotor activity and motor learning. Taken together, these results provide evidence that loss-of-function of SCN3A caused by reduced protein expression or deficient trafficking to the plasma membrane may contribute to increased seizure susceptibility.
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Affiliation(s)
- Tyra Lamar
- Department of Human Genetics, Emory University, Atlanta, GA, USA
| | - Carlos G Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jeffrey Calhoun
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, GA, USA
| | | | - Benjamin S Jorge
- Neuroscience Program, Vanderbilt University, Nashville, TN 37232, USA
| | - Milen Velinov
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA; Albert Einstein College of Medicine, Bronx, NY, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA, USA.
| | - Jennifer A Kearney
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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30
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Wong JC, Dutton SBB, Collins SD, Schachter S, Escayg A. Huperzine A Provides Robust and Sustained Protection against Induced Seizures in Scn1a Mutant Mice. Front Pharmacol 2016; 7:357. [PMID: 27799911 PMCID: PMC5065986 DOI: 10.3389/fphar.2016.00357] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/20/2016] [Indexed: 01/21/2023] Open
Abstract
De novo loss-of-function mutations in the voltage-gated sodium channel (VGSC) SCN1A (encoding Nav1.1) are the main cause of Dravet syndrome (DS), a catastrophic early-life encephalopathy associated with prolonged and recurrent early-life febrile seizures (FSs), refractory afebrile epilepsy, cognitive and behavioral deficits, and a 15–20% mortality rate. SCN1A mutations also lead to genetic epilepsy with febrile seizures plus (GEFS+), which is an inherited disorder characterized by early-life FSs and the development of a range of adult epilepsy subtypes. Current antiepileptic drugs often fail to protect against the severe seizures and behavioral and cognitive deficits found in patients with SCN1A mutations. To address the need for more efficacious treatments for SCN1A-derived epilepsies, we evaluated the therapeutic potential of Huperzine A, a naturally occurring reversible acetylcholinesterase inhibitor. In CF1 mice, Hup A (0.56 or 1 mg/kg) was found to confer protection against 6 Hz-, pentylenetetrazole (PTZ)-, and maximal electroshock (MES)-induced seizures. Robust protection against 6 Hz-, MES-, and hyperthermia-induced seizures was also achieved following Hup A administration in mouse models of DS (Scn1a+/−) and GEFS+ (Scn1aRH/+). Furthermore, Hup A-mediated seizure protection was sustained during 3 weeks of daily injections in Scn1aRH/+ mutants. Finally, we determined that muscarinic and GABAA receptors play a role in Hup A-mediated seizure protection. These findings indicate that Hup A might provide a novel therapeutic strategy for increasing seizure resistance in DS and GEFS+, and more broadly, in other forms of refractory epilepsy.
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Affiliation(s)
- Jennifer C Wong
- Department of Human Genetics, Emory University Atlanta, GA, USA
| | - Stacey B B Dutton
- Department of Human Genetics, Emory UniversityAtlanta, GA, USA; Department of Biology, Agnes Scott CollegeAtlanta, GA, USA
| | | | - Steven Schachter
- Department of Neurology, Harvard Medical School, Beth Israel Deaconess Medical Center, and Massachusetts General Hospital Boston, MA, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University Atlanta, GA, USA
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Bender AC, Luikart BW, Lenck-Santini PP. Cognitive Deficits Associated with Nav1.1 Alterations: Involvement of Neuronal Firing Dynamics and Oscillations. PLoS One 2016; 11:e0151538. [PMID: 26978272 PMCID: PMC4792481 DOI: 10.1371/journal.pone.0151538] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/11/2016] [Indexed: 11/19/2022] Open
Abstract
Brain oscillations play a critical role in information processing and may, therefore, be essential to uncovering the mechanisms of cognitive impairment in neurological disease. In Dravet syndrome (DS), a mutation in SCN1A, coding for the voltage-gated sodium channel Nav1.1, is associated with severe cognitive impairment and seizures. While seizure frequency and severity do not correlate with the extent of impairment, the slowing of brain rhythms may be involved. Here we investigate the role of Nav1.1 on brain rhythms and cognition using RNA interference. We demonstrate that knockdown of Nav1.1 impairs fast- and burst-firing properties of neurons in the medial septum in vivo. The proportion of neurons that fired phase-locked to hippocampal theta oscillations was reduced, and medial septal regulation of theta rhythm was disrupted. During a working memory task, this deficit was characterized by a decrease in theta frequency and was negatively correlated with performance. These findings suggest a fundamental role for Nav1.1 in facilitating fast-firing properties in neurons, highlight the importance of precise temporal control of theta frequency for working memory, and imply that Nav1.1 deficits may disrupt information processing in DS via a dysregulation of brain rhythms.
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Affiliation(s)
- Alex C. Bender
- Department of Neurology, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States of America
| | - Bryan W. Luikart
- Department of Physiology & Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States of America
| | - Pierre-Pascal Lenck-Santini
- Department of Neurological Sciences, University of Vermont, Burlington, VT, United States of America
- Institut de Neurobiologie de la Méditerranée, INSERM, Marseille, France
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Sawyer NT, Helvig AW, Makinson CD, Decker MJ, Neigh GN, Escayg A. Scn1a dysfunction alters behavior but not the effect of stress on seizure response. GENES, BRAIN, AND BEHAVIOR 2016; 15:335-47. [PMID: 26694226 DOI: 10.1111/gbb.12281] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/14/2015] [Accepted: 12/18/2015] [Indexed: 12/20/2022]
Abstract
Mutations in the voltage-gated sodium channel gene SCN1A are responsible for a number of epilepsy disorders, including genetic epilepsy with febrile seizures plus (GEFS+) and Dravet syndrome. In addition, dysfunction in SCN1A is increasingly being linked to neuropsychiatric abnormalities, social deficits and cognitive disabilities. We have previously reported that mice heterozygous for the SCN1A R1648H mutation identified in a GEFS+ family have infrequent spontaneous seizures, increased susceptibility to chemically and hyperthermia-induced generalized seizures and sleep abnormalities. In this study, we characterized the behavior of heterozygous mice expressing the SCN1A R1648H mutation (Scn1a(RH/+)) and the effect of stress on spontaneous and induced seizures. We also examined the effect of the R1648H mutation on the hypothalamic-pituitary-adrenal (HPA) axis response. We confirmed our previous finding that Scn1a(RH/+) mutants are hyperactive, and also identified deficits in social behavior, spatial memory, cued fear conditioning, pre-pulse inhibition and risk assessment. Furthermore, while exposure to a stressor did increase seizure susceptibility, the effect seen in the Scn1a(RH/+) mutants was similar to that seen in wild-type littermates. In addition, Scn1a dysfunction does not appear to alter HPA axis function in adult animals. Our results suggest that the behavioral abnormalities associated with Scn1a dysfunction encompass a wider range of phenotypes than previously reported and factors such as stress exposure may alter disease severity in patients with SCN1A mutations.
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Affiliation(s)
- N T Sawyer
- Department of Human Genetics, Emory University, Atlanta, GA
- Department of Biology, Clayton State University, Morrow, GA
| | - A W Helvig
- Byrdine F. Lewis School of Nursing and Health Professions, Georgia State University, Atlanta, GA
| | - C D Makinson
- Department of Human Genetics, Emory University, Atlanta, GA
| | - M J Decker
- Departments of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH
- Department of Neuroscience, School of Nursing, Case Western Reserve University, Cleveland, OH
| | - G N Neigh
- Department of Physiology, Emory University, Atlanta, GA, USA
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
| | - A Escayg
- Department of Human Genetics, Emory University, Atlanta, GA
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Schutte SS, Schutte RJ, Barragan EV, O'Dowd DK. Model systems for studying cellular mechanisms of SCN1A-related epilepsy. J Neurophysiol 2016; 115:1755-66. [PMID: 26843603 DOI: 10.1152/jn.00824.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 01/22/2016] [Indexed: 11/22/2022] Open
Abstract
Mutations in SCN1A, the gene encoding voltage-gated sodium channel NaV1.1, cause a spectrum of epilepsy disorders that range from genetic epilepsy with febrile seizures plus to catastrophic disorders such as Dravet syndrome. To date, more than 1,250 mutations in SCN1A have been linked to epilepsy. Distinct effects of individual SCN1A mutations on neuronal function are likely to contribute to variation in disease severity and response to treatment in patients. Several model systems have been used to explore seizure genesis in SCN1A epilepsies. In this article we review what has been learned about cellular mechanisms and potential new therapies from these model systems, with a particular emphasis on the novel model system of knock in Drosophila and a look toward the future with expanded use of patient-specific induced pluripotent stem cell-derived neurons.
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Affiliation(s)
- Soleil S Schutte
- Department of Developmental and Cell Biology and Department of Anatomy and Neurobiology, University of California, Irvine, California
| | - Ryan J Schutte
- Department of Developmental and Cell Biology and Department of Anatomy and Neurobiology, University of California, Irvine, California
| | - Eden V Barragan
- Department of Developmental and Cell Biology and Department of Anatomy and Neurobiology, University of California, Irvine, California
| | - Diane K O'Dowd
- Department of Developmental and Cell Biology and Department of Anatomy and Neurobiology, University of California, Irvine, California
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Makinson CD, Dutt K, Lin F, Papale LA, Shankar A, Barela AJ, Liu R, Goldin AL, Escayg A. An Scn1a epilepsy mutation in Scn8a alters seizure susceptibility and behavior. Exp Neurol 2015; 275 Pt 1:46-58. [PMID: 26410685 DOI: 10.1016/j.expneurol.2015.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 09/03/2015] [Accepted: 09/12/2015] [Indexed: 11/26/2022]
Abstract
Understanding the role of SCN8A in epilepsy and behavior is critical in light of recently identified human SCN8A epilepsy mutations. We have previously demonstrated that Scn8a(med) and Scn8a(med-jo) mice carrying mutations in the Scn8a gene display increased resistance to flurothyl and kainic acid-induced seizures; however, they also exhibit spontaneous absence seizures. To further investigate the relationship between altered SCN8A function and epilepsy, we introduced the SCN1A-R1648H mutation, identified in a family with generalized epilepsy with febrile seizures plus (GEFS+), into the corresponding position (R1627H) of the mouse Scn8a gene. Heterozygous R1627H mice exhibited increased resistance to some forms of pharmacologically and electrically induced seizures and the mutant Scn8a allele ameliorated the phenotype of Scn1a-R1648H mutants. Hippocampal slices from heterozygous R1627H mice displayed decreased bursting behavior compared to wild-type littermates. Paradoxically, at the homozygous level, R1627H mice did not display increased seizure resistance and were susceptible to audiogenic seizures. We furthermore observed increased hippocampal pyramidal cell excitability in heterozygous and homozygous Scn8a-R1627H mutants, and decreased interneuron excitability in heterozygous Scn8a-R1627H mutants. These results expand the phenotypes associated with disruption of the Scn8a gene and demonstrate that an Scn8a mutation can both confer seizure protection and increase seizure susceptibility.
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Affiliation(s)
| | - Karoni Dutt
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, CA 92697, USA
| | - Frank Lin
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Ligia A Papale
- Department of Human Genetics, Emory University, Atlanta, GA 30022, USA
| | - Anupama Shankar
- Department of Human Genetics, Emory University, Atlanta, GA 30022, USA
| | - Arthur J Barela
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, CA 92697, USA
| | - Robert Liu
- Department of Biology, Emory University, Atlanta, GA 30022, USA
| | - Alan L Goldin
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, CA 92697, USA.
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA 30022, USA.
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Petruccelli E, Lansdon P, Kitamoto T. Exaggerated Nighttime Sleep and Defective Sleep Homeostasis in a Drosophila Knock-In Model of Human Epilepsy. PLoS One 2015; 10:e0137758. [PMID: 26361221 PMCID: PMC4567262 DOI: 10.1371/journal.pone.0137758] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/20/2015] [Indexed: 01/17/2023] Open
Abstract
Despite an established link between epilepsy and sleep behavior, it remains unclear how specific epileptogenic mutations affect sleep and subsequently influence seizure susceptibility. Recently, Sun et al. (2012) created a fly knock-in model of human generalized epilepsy with febrile seizures plus (GEFS+), a wide-spectrum disorder characterized by fever-associated seizing in childhood and lifelong affliction. GEFS+ flies carry a disease-causing mutation in their voltage-gated sodium channel (VGSC) gene and display semidominant heat-induced seizing, likely due to reduced GABAergic inhibitory activity at high temperature. Here, we show that at room temperature the GEFS+ mutation dominantly modifies sleep, with mutants exhibiting rapid sleep onset at dusk and increased nighttime sleep as compared to controls. These characteristics of GEFS+ sleep were observed regardless of sex, mating status, and genetic background. GEFS+ mutant sleep phenotypes were more resistant to pharmacologic reduction of GABA transmission by carbamazepine (CBZ) than controls, and were mitigated by reducing GABAA receptor expression specifically in wake-promoting pigment dispersing factor (PDF) neurons. These findings are consistent with increased GABAergic transmission to PDF neurons being mainly responsible for the enhanced nighttime sleep of GEFS+ mutants. Additionally, analyses under other light conditions suggested that the GEFS+ mutation led to reduced buffering of behavioral responses to light on and off stimuli, which contributed to characteristic GEFS+ sleep phenotypes. We further found that GEFS+ mutants had normal circadian rhythms in free-running dark conditions. Interestingly, the mutants lacked a homeostatic rebound following mechanical sleep deprivation, and whereas deprivation treatment increased heat-induced seizure susceptibility in control flies, it unexpectedly reduced seizure activity in GEFS+ mutants. Our study has revealed the sleep architecture of a Drosophila VGSC mutant that harbors a human GEFS+ mutation, and provided unique insight into the relationship between sleep and epilepsy.
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Affiliation(s)
- Emily Petruccelli
- Interdisciplinary Program in Genetics, University of Iowa, Iowa City, IA, United States of America
| | - Patrick Lansdon
- Interdisciplinary Program in Genetics, University of Iowa, Iowa City, IA, United States of America
| | - Toshihiro Kitamoto
- Interdisciplinary Program in Genetics, University of Iowa, Iowa City, IA, United States of America
- Department of Anesthesia, Carver College of Medicine, University of Iowa, Iowa City, IA, United States of America
- * E-mail:
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Kalume F, Oakley JC, Westenbroek RE, Gile J, de la Iglesia HO, Scheuer T, Catterall WA. Sleep impairment and reduced interneuron excitability in a mouse model of Dravet Syndrome. Neurobiol Dis 2015; 77:141-54. [PMID: 25766678 DOI: 10.1016/j.nbd.2015.02.016] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 02/12/2015] [Accepted: 02/19/2015] [Indexed: 01/17/2023] Open
Abstract
Dravet Syndrome (DS) is caused by heterozygous loss-of-function mutations in voltage-gated sodium channel NaV1.1. Our mouse genetic model of DS recapitulates its severe seizures and premature death. Sleep disturbance is common in DS, but its mechanism is unknown. Electroencephalographic studies revealed abnormal sleep in DS mice, including reduced delta wave power, reduced sleep spindles, increased brief wakes, and numerous interictal spikes in Non-Rapid-Eye-Movement sleep. Theta power was reduced in Rapid-Eye-Movement sleep. Mice with NaV1.1 deleted specifically in forebrain interneurons exhibited similar sleep pathology to DS mice, but without changes in circadian rhythm. Sleep architecture depends on oscillatory activity in the thalamocortical network generated by excitatory neurons in the ventrobasal nucleus (VBN) of the thalamus and inhibitory GABAergic neurons in the reticular nucleus of the thalamus (RNT). Whole-cell NaV current was reduced in GABAergic RNT neurons but not in VBN neurons. Rebound firing of action potentials following hyperpolarization, the signature firing pattern of RNT neurons during sleep, was also reduced. These results demonstrate imbalance of excitatory vs. inhibitory neurons in this circuit. As predicted from this functional impairment, we found substantial deficit in homeostatic rebound of slow wave activity following sleep deprivation. Although sleep disorders in epilepsies have been attributed to anti-epileptic drugs, our results show that sleep disorder in DS mice arises from loss of NaV1.1 channels in forebrain GABAergic interneurons without drug treatment. Impairment of NaV currents and excitability of GABAergic RNT neurons are correlated with impaired sleep quality and homeostasis in these mice.
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Affiliation(s)
- Franck Kalume
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Department of Neurological Surgery, University of Washington, Seattle, WA 98195, USA; Center for Integrative Brain Research, Seattle Children Hospital Research Institute, Seattle, WA 98101, USA
| | - John C Oakley
- Department of Neurology, University of Washington, Seattle, WA 98195, USA
| | - Ruth E Westenbroek
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Jennifer Gile
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Department of Biology, University of Washington, Seattle, WA 98195, USA
| | | | - Todd Scheuer
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
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Puzerey PA, Decker MJ, Galán RF. Elevated serotonergic signaling amplifies synaptic noise and facilitates the emergence of epileptiform network oscillations. J Neurophysiol 2014; 112:2357-73. [PMID: 25122717 DOI: 10.1152/jn.00031.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Serotonin fibers densely innervate the cortical sheath to regulate neuronal excitability, but its role in shaping network dynamics remains undetermined. We show that serotonin provides an excitatory tone to cortical neurons in the form of spontaneous synaptic noise through 5-HT3 receptors, which is persistent and can be augmented using fluoxetine, a selective serotonin re-uptake inhibitor. Augmented serotonin signaling also increases cortical network activity by enhancing synaptic excitation through activation of 5-HT2 receptors. This in turn facilitates the emergence of epileptiform network oscillations (10-16 Hz) known as fast runs. A computational model of cortical dynamics demonstrates that these two combined mechanisms, increased background synaptic noise and enhanced synaptic excitation, are sufficient to replicate the emergence fast runs and their statistics. Consistent with these findings, we show that blocking 5-HT2 receptors in vivo significantly raises the threshold for convulsant-induced seizures.
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Affiliation(s)
- Pavel A Puzerey
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and
| | - Michael J Decker
- School of Nursing, Case Western Reserve University, Cleveland, Ohio
| | - Roberto F Galán
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and
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McClelland S, Brennan GP, Dubé C, Rajpara S, Iyer S, Richichi C, Bernard C, Baram TZ. The transcription factor NRSF contributes to epileptogenesis by selective repression of a subset of target genes. eLife 2014; 3:e01267. [PMID: 25117540 PMCID: PMC4129437 DOI: 10.7554/elife.01267] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The mechanisms generating epileptic neuronal networks following insults such as severe seizures are unknown. We have previously shown that interfering with the function of the neuron-restrictive silencer factor (NRSF/REST), an important transcription factor that influences neuronal phenotype, attenuated development of this disorder. In this study, we found that epilepsy-provoking seizures increased the low NRSF levels in mature hippocampus several fold yet surprisingly, provoked repression of only a subset (∼10%) of potential NRSF target genes. Accordingly, the repressed gene-set was rescued when NRSF binding to chromatin was blocked. Unexpectedly, genes selectively repressed by NRSF had mid-range binding frequencies to the repressor, a property that rendered them sensitive to moderate fluctuations of NRSF levels. Genes selectively regulated by NRSF during epileptogenesis coded for ion channels, receptors, and other crucial contributors to neuronal function. Thus, dynamic, selective regulation of NRSF target genes may play a role in influencing neuronal properties in pathological and physiological contexts. DOI:http://dx.doi.org/10.7554/eLife.01267.001 Epilepsy is a common brain disease that can cause disabling seizures. During a seizure, brain cells send out abnormal signals, which can mean that people having seizures may be unaware of their surroundings and may fall or otherwise injure themselves. Individuals with epilepsy develop changes in their brain cells and in the circuits that connect these cells together. Some people develop epilepsy because they have mutations in genes. Others develop the condition after an injury or a long seizure, which leads to changes in gene expression and therefore changes to the brain's cells and circuits. In 2011, researchers found that a protein that normally switches off the expression of certain genes during brain development, but which is almost absent in the adult brain, may run amok after a seizure. The level of this protein—a transcription factor called NRSF—increased in the brains of rats that had been caused to have a seizure. A long provoked seizure caused many of the rats to develop epilepsy. But, if NRSF was blocked after the original seizure, the rats were less likely to have further seizures later on. Now McClelland et al., including several of the researchers involved in the 2011 work, have examined what normally happens to the expression of genes after a seizure and what happens when the NRSF transcription factor is blocked. McClelland et al. found that only a small subset—about 10%—of the genes that can theoretically be silenced by NRSF are switched off in the brain when this protein's levels increase after a seizure. The increased NRSF levels, unexpectedly, did not affect the genes that bind tightly to this transcription factor. Nor did NRSF affect genes that bind loosely. Instead, the genes that the transcription factor binds to with an intermediate strength were the ones that were switched off. McClelland et al. suggest that this ‘mid-range binding’ to NRSF allows the expression of these genes to be increased or decreased in response to there being more or less NRSF in the cell. Genes that bind tightly to NRSF are likely to already have a lot of NRSF bound and are therefore already switched off; and loosely-binding genes would likely need even more NRSF before they are switched off. The subset of genes that were switched off by the increased levels of NRSF after a seizure code for a number of proteins that brain cells need to be able to effectively send and receive messages. Blocking the ability of NRSF to bind to these genes and switch them off may help to prevent the brain changes that cause epilepsy. DOI:http://dx.doi.org/10.7554/eLife.01267.002
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Affiliation(s)
- Shawn McClelland
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States Department of Pediatrics, University of California, Irvine, Irvine, United States Department of Neurology, University of California, Irvine, Irvine, United States
| | - Gary P Brennan
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States Department of Pediatrics, University of California, Irvine, Irvine, United States Department of Neurology, University of California, Irvine, Irvine, United States
| | - Celine Dubé
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States Department of Pediatrics, University of California, Irvine, Irvine, United States Department of Neurology, University of California, Irvine, Irvine, United States
| | - Seeta Rajpara
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States Department of Pediatrics, University of California, Irvine, Irvine, United States Department of Neurology, University of California, Irvine, Irvine, United States
| | - Shruti Iyer
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States Department of Pediatrics, University of California, Irvine, Irvine, United States Department of Neurology, University of California, Irvine, Irvine, United States
| | - Cristina Richichi
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States Department of Pediatrics, University of California, Irvine, Irvine, United States Department of Neurology, University of California, Irvine, Irvine, United States
| | - Christophe Bernard
- Laboratoire Epilepsie et Cognition, Institut National de la Santé et de la Recherche Médicale, Marseille, France
| | - Tallie Z Baram
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States Department of Pediatrics, University of California, Irvine, Irvine, United States Department of Neurology, University of California, Irvine, Irvine, United States
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PER2 rs2304672, CLOCK rs1801260, and PER3 rs57875989 polymorphisms are not associated with juvenile myoclonic epilepsy. Epilepsy Behav 2014; 36:82-5. [PMID: 24892753 DOI: 10.1016/j.yebeh.2014.04.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/24/2014] [Accepted: 04/29/2014] [Indexed: 11/23/2022]
Abstract
Sleep disturbance is common in several epilepsy types, such as juvenile myoclonic epilepsy (JME). Genetic background could increase susceptibility to seizure and sleep abnormalities. From this perspective, a susceptibility gene for sleep disturbance or chronotype could contribute to the genetic susceptibility threshold for epilepsy and vice versa. Accordingly, we investigated whether functional clock gene polymorphisms (PER2 111C>G, CLOCK 3111T>C, and PER3 VNTR) might influence the risk for JME. All these polymorphisms have recently been reported to be associated with sleep disturbance, diurnal variation, and neurological diseases. The polymorphisms were genotyped in 97 patients and 212 controls using polymerase chain reaction or restriction fragment length polymorphism methods. No significant differences were observed in the genotypic and allelic frequencies of these polymorphisms between cases and controls even when analyses were restricted to patients that presented a diurnal preferential seizure occurrence. We also tested for interactions between polymorphisms by multifactor dimensionality reduction analysis. None of the combined genotypes differed significantly between the groups. These results present no evidence for an association of these polymorphisms with JME. Further studies including other types of epilepsy and/or other functional polymorphisms are required to investigate the possible relationship between clock genes and the genetic susceptibility to chronic seizure.
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Dhamija R, Erickson MK, St Louis EK, Wirrell E, Kotagal S. Sleep abnormalities in children with Dravet syndrome. Pediatr Neurol 2014; 50:474-8. [PMID: 24656210 DOI: 10.1016/j.pediatrneurol.2014.01.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 12/17/2013] [Accepted: 01/01/2014] [Indexed: 01/06/2023]
Abstract
BACKGROUND Mutations in the voltage-gated sodium channel SCN1A gene are responsible for the majority of Dravet syndrome cases. There is evidence that the Nav1.1 channel coded by the SCN1A gene is involved in sleep regulation. We evaluated sleep abnormalities in children with Dravet syndrome using nocturnal polysomnography. METHODS We identified six children at our institution with genetically confirmed Dravet syndrome who had also undergone formal sleep consultation with nocturnal polysomnography. Indications for polysomnography were parental concern of daytime fatigue or sleepiness, hyperactivity, inattention, disruptive behavior, nighttime awakenings, or nocturnal seizures. Sleep studies were scored according to guidelines of the American Academy of Sleep Medicine and non-rapid eye movement cyclic alternating pattern was visually identified and scored according to established methods. RESULTS The mean age of the subjects at the time of polysomnography was 6 years. Standard polysomnography did not show any consistent abnormalities in the obstructive or central apnea index, arousal index, sleep efficiency, or architecture. Cyclic alternating pattern analysis on five patients showed an increased mean rate of 50.3% (vs 31% to 34% in neurological normal children) with a mild increase in A1 subtype of 89.4% (vs 84.5%). A2/A3 subtype (5.3% vs 7.3%) and B phase duration (22.4 vs 24.7 seconds) were similar to previously reported findings in neurologically normal children. CONCLUSION Despite parental concerns for sleep disturbance in patients with Dravet syndrome, we could not identify abnormalities in sleep macroarchitecture. Non-rapid eye movement sleep microarchitecture was, however, abnormal, with increased A1 subtype, somewhat resembling a tracé alternant pattern of neonates and possibly suggestive of cortical synaptic immaturity in Dravet syndrome. Larger studies are needed to replicate these results.
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Affiliation(s)
- Radhika Dhamija
- Department of Medical Genetics, Mayo Clinic, Rochester, Minnesota
| | - Maia K Erickson
- Center for Sleep Medicine, Mayo Clinic, Rochester, Minnesota
| | - Erik K St Louis
- Department of Neurology, Mayo Clinic, Rochester, Minnesota; Center for Sleep Medicine, Mayo Clinic, Rochester, Minnesota
| | - Elaine Wirrell
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Suresh Kotagal
- Department of Neurology, Mayo Clinic, Rochester, Minnesota; Center for Sleep Medicine, Mayo Clinic, Rochester, Minnesota.
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Makinson CD, Tanaka BS, Lamar T, Goldin AL, Escayg A. Role of the hippocampus in Nav1.6 (Scn8a) mediated seizure resistance. Neurobiol Dis 2014; 68:16-25. [PMID: 24704313 DOI: 10.1016/j.nbd.2014.03.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 03/13/2014] [Accepted: 03/25/2014] [Indexed: 10/25/2022] Open
Abstract
SCN1A mutations are the main cause of the epilepsy disorders Dravet syndrome (DS) and genetic epilepsy with febrile seizures plus (GEFS+). Mutations that reduce the activity of the mouse Scn8a gene, in contrast, are found to confer seizure resistance and extend the lifespan of mouse models of DS and GEFS+. To investigate the mechanism by which reduced Scn8a expression confers seizure resistance, we induced interictal-like burst discharges in hippocampal slices of heterozygous Scn8a null mice (Scn8a(med/+)) with elevated extracellular potassium. Scn8a(med/+) mutants exhibited reduced epileptiform burst discharge activity after P20, indicating an age-dependent increased threshold for induction of epileptiform discharges. Scn8a deficiency also reduced the occurrence of burst discharges in a GEFS+ mouse model (Scn1a(R1648H/+)). There was no detectable change in the expression levels of Scn1a (Nav1.1) or Scn2a (Nav1.2) in the hippocampus of adult Scn8a(med/+) mutants. To determine whether the increased seizure resistance associated with reduced Scn8a expression was due to alterations that occurred during development, we examined the effect of deleting Scn8a in adult mice. Global Cre-mediated deletion of a heterozygous floxed Scn8a allele in adult mice was found to increase thresholds to chemically and electrically induced seizures. Finally, knockdown of Scn8a gene expression in the adult hippocampus via lentiviral Cre injection resulted in a reduction in the number of EEG-confirmed seizures following the administration of picrotoxin. Our results identify the hippocampus as an important structure in the mediation of Scn8a-dependent seizure protection and suggest that selective targeting of Scn8a activity might be efficacious in patients with epilepsy.
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Affiliation(s)
| | - Brian S Tanaka
- Departments of Microbiology and Molecular Genetics and Anatomy and Neurobiology, University of California, Irvine, CA 92697
| | - Tyra Lamar
- Department of Human Genetics, Emory University, Atlanta, GA 30322
| | - Alan L Goldin
- Departments of Microbiology and Molecular Genetics and Anatomy and Neurobiology, University of California, Irvine, CA 92697
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA 30322
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