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He G, Zheng Y, Chang S, Wang L, Yang X, Hao H, Li J, Zhang X, Tian F, Liang X, Xu H, Wang P, Chen X, Cao Z, Fang S, Gao Z, Liu H. Discovery of Novel Pyrimidine-Based Derivatives as Nav1.2 Inhibitors with Efficacy in Mouse Models of Epilepsy. J Med Chem 2024. [PMID: 39037114 DOI: 10.1021/acs.jmedchem.4c00861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Dysfunction of voltage-gated sodium channel Nav1.2 causes various epileptic disorders, and inhibition of the channel has emerged as an attractive therapeutic strategy. However, currently available Nav1.2 inhibitors exhibit low potency and limited structural diversity. In this study, a novel series of pyrimidine-based derivatives with Nav1.2 inhibitory activity were designed, synthesized, and evaluated. Compounds 14 and 35 exhibited potent activity against Nav1.2, boasting IC50 values of 120 and 65 nM, respectively. Compound 14 displayed favorable pharmacokinetics (F = 43%) following intraperitoneal injection and excellent brain penetration potency (B/P = 3.6). Compounds 14 and 35 exhibited robust antiepileptic activities in the maximal electroshock test, with ED50 values of 3.2 and 11.1 mg/kg, respectively. Compound 35 also demonstrated potent antiepileptic activity in a 6 Hz (32 mA) model, with an ED50 value of 18.5 mg/kg. Overall, compounds 14 and 35 are promising leads for the development of new small-molecule therapeutics for epilepsy.
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Affiliation(s)
- Guoxue He
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yueming Zheng
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shunzhen Chang
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Long Wang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- Pharmacophenomics Laboratory, Human Phenome Institute, Fudan University, Shanghai 201203, China
| | - Xiaohao Yang
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haishuang Hao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jiyuan Li
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Xian Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Fuyun Tian
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xuewu Liang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haiyan Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Pei Wang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xueqin Chen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Zeyu Cao
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sui Fang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Zhaobing Gao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Hong Liu
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
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Vanoye CG, Abramova TV, DeKeyser JM, Ghabra NF, Oudin MJ, Burge CB, Helbig I, Thompson CH, George AL. Molecular and cellular context influences SCN8A variant function. JCI Insight 2024; 9:e177530. [PMID: 38771640 DOI: 10.1172/jci.insight.177530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 05/15/2024] [Indexed: 05/23/2024] Open
Abstract
Pathogenic variants in SCN8A, which encodes the voltage-gated sodium (NaV) channel NaV1.6, associate with neurodevelopmental disorders, including developmental and epileptic encephalopathy. Previous approaches to determine SCN8A variant function may be confounded by use of a neonatally expressed, alternatively spliced isoform of NaV1.6 (NaV1.6N) and engineered mutations rendering the channel tetrodotoxin (TTX) resistant. We investigated the impact of SCN8A alternative splicing on variant function by comparing the functional attributes of 15 variants expressed in 2 developmentally regulated splice isoforms (NaV1.6N, NaV1.6A). We employed automated patch clamp recording to enhance throughput, and developed a neuronal cell line (ND7/LoNav) with low levels of endogenous NaV current to obviate the need for TTX-resistance mutations. Expression of NaV1.6N or NaV1.6A in ND7/LoNav cells generated NaV currents with small, but significant, differences in voltage dependence of activation and inactivation. TTX-resistant versions of both isoforms exhibited significant functional differences compared with the corresponding WT channels. We demonstrated that many of the 15 disease-associated variants studied exhibited isoform-dependent functional effects, and that many of the studied SCN8A variants exhibited functional properties that were not easily classified as either gain- or loss-of-function. Our work illustrates the value of considering molecular and cellular context when investigating SCN8A variants.
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Affiliation(s)
- Carlos G Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Tatiana V Abramova
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Jean-Marc DeKeyser
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Nora F Ghabra
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Madeleine J Oudin
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, USA
| | - Christopher B Burge
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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3
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Yang Y, Chen Z, Zhou J, Jiang S, Wang G, Wan L, Yu J, Jiang M, Wang Y, Hu J, Liu X, Wang Y. Anti-PD-1 treatment protects against seizure by suppressing sodium channel function. CNS Neurosci Ther 2024; 30:e14504. [PMID: 37904722 PMCID: PMC11017438 DOI: 10.1111/cns.14504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 11/01/2023] Open
Abstract
AIMS Although programmed cell death protein 1 (PD-1) typically serves as a target for immunotherapies, a few recent studies have found that PD-1 is expressed in the nervous system and that neuronal PD-1 might play a crucial role in regulating neuronal excitability. However, whether brain-localized PD-1 is involved in seizures and epileptogenesis is still unknown and worthy of in-depth exploration. METHODS The existence of PD-1 in human neurons was confirmed by immunohistochemistry, and PD-1 expression levels were measured by real-time quantitative PCR (RT-qPCR) and western blotting. Chemoconvulsants, pentylenetetrazol (PTZ) and cyclothiazide (CTZ), were applied for the establishment of in vivo (rodents) and in vitro (primary hippocampal neurons) models of seizure, respectively. SHR-1210 (a PD-1 monoclonal antibody) and sodium stibogluconate (SSG, a validated inhibitor of SH2-containing protein tyrosine phosphatase-1 [SHP-1]) were administrated to investigate the impact of PD-1 pathway blockade on epileptic behaviors of rodents and epileptiform discharges of neurons. A miRNA strategy was applied to determine the impact of PD-1 knockdown on neuronal excitability. The electrical activities and sodium channel function of neurons were determined by whole-cell patch-clamp recordings. The interaction between PD-1 and α-6 subunit of human voltage-gated sodium channel (Nav1.6) was validated by performing co-immunostaining and co-immunoprecipitation (co-IP) experiments. RESULTS Our results reveal that PD-1 protein and mRNA levels were upregulated in lesion cores compared with perifocal tissues of surgically resected specimens from patients with intractable epilepsy. Furthermore, we show that anti-PD-1 treatment has anti-seizure effects both in vivo and in vitro. Then, we reveal that PD-1 blockade can alter the electrophysiological properties of sodium channels. Moreover, we reveal that PD-1 acts together with downstream SHP-1 to regulate sodium channel function and hence neuronal excitability. Further investigation suggests that there is a direct interaction between neuronal PD-1 and Nav1.6. CONCLUSION Our study reveals that neuronal PD-1 plays an important role in epilepsy and that anti-PD-1 treatment protects against seizures by suppressing sodium channel function, identifying anti-PD-1 treatment as a novel therapeutic strategy for epilepsy.
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Affiliation(s)
- Yuling Yang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Zhiyun Chen
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Jing Zhou
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
- Rehabilitation CenterShenzhen Second People's Hospital/The First Affiliated Hospital of Shenzhen University Health Science CenterShenzhenChina
| | - Shize Jiang
- Department of Neurosurgery, Huashan HospitalFudan UniversityShanghaiChina
| | - Guoxiang Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Li Wan
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
- Rehabilitation CenterShenzhen Second People's Hospital/The First Affiliated Hospital of Shenzhen University Health Science CenterShenzhenChina
| | - Jiangning Yu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Min Jiang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Yulong Wang
- Rehabilitation CenterShenzhen Second People's Hospital/The First Affiliated Hospital of Shenzhen University Health Science CenterShenzhenChina
| | - Jie Hu
- Department of Neurosurgery, Huashan HospitalFudan UniversityShanghaiChina
| | - Xu Liu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
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Barlow BSM, Longtin A, Joós B. Impact on backpropagation of the spatial heterogeneity of sodium channel kinetics in the axon initial segment. PLoS Comput Biol 2024; 20:e1011846. [PMID: 38489374 PMCID: PMC10942053 DOI: 10.1371/journal.pcbi.1011846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 01/21/2024] [Indexed: 03/17/2024] Open
Abstract
In a variety of neurons, action potentials (APs) initiate at the proximal axon, within a region called the axon initial segment (AIS), which has a high density of voltage-gated sodium channels (NaVs) on its membrane. In pyramidal neurons, the proximal AIS has been reported to exhibit a higher proportion of NaVs with gating properties that are "right-shifted" to more depolarized voltages, compared to the distal AIS. Further, recent experiments have revealed that as neurons develop, the spatial distribution of NaV subtypes along the AIS can change substantially, suggesting that neurons tune their excitability by modifying said distribution. When neurons are stimulated axonally, computational modelling has shown that this spatial separation of gating properties in the AIS enhances the backpropagation of APs into the dendrites. In contrast, in the more natural scenario of somatic stimulation, our simulations show that the same distribution can impede backpropagation, suggesting that the choice of orthodromic versus antidromic stimulation can bias or even invert experimental findings regarding the role of NaV subtypes in the AIS. We implemented a range of hypothetical NaV distributions in the AIS of three multicompartmental pyramidal cell models and investigated the precise kinetic mechanisms underlying such effects, as the spatial distribution of NaV subtypes is varied. With axonal stimulation, proximal NaV availability dominates, such that concentrating right-shifted NaVs in the proximal AIS promotes backpropagation. However, with somatic stimulation, the models are insensitive to availability kinetics. Instead, the higher activation threshold of right-shifted NaVs in the AIS impedes backpropagation. Therefore, recently observed developmental changes to the spatial separation and relative proportions of NaV1.2 and NaV1.6 in the AIS differentially impact activation and availability. The observed effects on backpropagation, and potentially learning via its putative role in synaptic plasticity (e.g. through spike-timing-dependent plasticity), are opposite for orthodromic versus antidromic stimulation, which should inform hypotheses about the impact of the developmentally regulated subcellular localization of these NaV subtypes.
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Affiliation(s)
- Benjamin S. M. Barlow
- Department of Physics, University of Ottawa, STEM Complex, 150 Louis-Pasteur Pvt, Ottawa, Ontario, Canada
| | - André Longtin
- Department of Physics, University of Ottawa, STEM Complex, 150 Louis-Pasteur Pvt, Ottawa, Ontario, Canada
- Center for Neural Dynamics and AI, University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Béla Joós
- Department of Physics, University of Ottawa, STEM Complex, 150 Louis-Pasteur Pvt, Ottawa, Ontario, Canada
- Center for Neural Dynamics and AI, University of Ottawa, Ottawa, Ontario, Canada
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5
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Vanoye CG, Abramova TV, DeKeyser JM, Ghabra NF, Oudin MJ, Burge CB, Helbig I, Thompson CH, George AL. Molecular and Cellular Context Influences SCN8A Variant Function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.11.566702. [PMID: 38014225 PMCID: PMC10680676 DOI: 10.1101/2023.11.11.566702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Pathogenic variants in SCN8A , which encodes the voltage-gated sodium (Na V ) channel Na V 1.6, are associated with neurodevelopmental disorders including epileptic encephalopathy. Previous approaches to determine SCN8A variant function may be confounded by the use of a neonatal-expressed alternatively spliced isoform of Na V 1.6 (Na V 1.6N), and engineered mutations to render the channel tetrodotoxin (TTX) resistant. In this study, we investigated the impact of SCN8A alternative splicing on variant function by comparing the functional attributes of 15 variants expressed in two developmentally regulated splice isoforms (Na V 1.6N, Na V 1.6A). We employed automated patch clamp recording to enhance throughput, and developed a novel neuronal cell line (ND7/LoNav) with low levels of endogenous Na V current to obviate the need for TTX-resistance mutations. Expression of Na V 1.6N or Na V 1.6A in ND7/LoNav cells generated Na V currents that differed significantly in voltage-dependence of activation and inactivation. TTX-resistant versions of both isoforms exhibited significant functional differences compared to the corresponding wild-type (WT) channels. We demonstrated that many of the 15 disease-associated variants studied exhibited isoform-dependent functional effects, and that many of the studied SCN8A variants exhibited functional properties that were not easily classified as either gain- or loss-of-function. Our work illustrates the value of considering molecular and cellular context when investigating SCN8A variants.
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6
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Cheng A, Xiong Q, Wang J, Wang R, Shen L, Zhang G, Huang Y. Development and validation of a predictive model for febrile seizures. Sci Rep 2023; 13:18779. [PMID: 37907555 PMCID: PMC10618474 DOI: 10.1038/s41598-023-45911-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 10/25/2023] [Indexed: 11/02/2023] Open
Abstract
Febrile seizures (FS) are the most prevalent type of seizures in children. Existing predictive models for FS exhibit limited predictive ability. To build a better-performing predictive model, a retrospective analysis study was conducted on febrile children who visited the Children's Hospital of Shanghai from July 2020 to March 2021. These children were divided into training set (n = 1453), internal validation set (n = 623) and external validation set (n = 778). The variables included demographic data and complete blood counts (CBCs). The least absolute shrinkage and selection operator (LASSO) method was used to select the predictors of FS. Multivariate logistic regression analysis was used to develop a predictive model. The coefficients derived from the multivariate logistic regression were used to construct a nomogram that predicts the probability of FS. The calibration plot, area under the receiver operating characteristic curve (AUC), and decision curve analysis (DCA) were used to evaluate model performance. Results showed that the AUC of the predictive model in the training set was 0.884 (95% CI 0.861 to 0.908, p < 0.001) and C-statistic of the nomogram was 0.884. The AUC of internal validation set was 0.883 (95% CI 0.844 to 0.922, p < 0.001), and the AUC of external validation set was 0.858 (95% CI 0.820 to 0.896, p < 0.001). In conclusion, the FS predictive model constructed based on CBCs in this study exhibits good predictive ability and has clinical application value.
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Affiliation(s)
- Anna Cheng
- Department of Emergency, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Qin Xiong
- Department of Emergency, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jing Wang
- Department of Emergency, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Renjian Wang
- Department of Emergency, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lei Shen
- Department of Emergency, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Guoqin Zhang
- Department of Emergency, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yujuan Huang
- Department of Emergency, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
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Laliberté A, Myers KA. Ataxia and Diplopia: A New SCN8A-Related Phenotype. Neurol Genet 2023; 9:e200085. [PMID: 37440794 PMCID: PMC10335842 DOI: 10.1212/nxg.0000000000200085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/09/2023] [Indexed: 07/15/2023]
Abstract
Objectives The objective of this study was to describe the first patient with recurrent ataxia and diplopia in association with a pathogenic variant in SCN8A. Methods We identified a girl with a heterozygous SCN8A pathogenic variant and performed thorough phenotyping. Results A 10-year-old girl was previously well with normal intelligence. She had recurrent diplopia, dysmetria, and unsteady gait, which occurred only in the context of febrile illnesses. EEG during her initial acute episode showed multifocal epileptiform discharges, with similar findings seen on a follow-up study 3 months later when she was well. Brain MRI finding was normal. A gene panel identified a de novo SCN8A variant, p.Arg847Gln, classified as likely pathogenic. One year after her initial presentation, the girl is well and developmentally normal and has never had an event concerning for seizure. Discussion This case presentation demonstrates that SCN8A pathogenic variants should be considered in children with transient ataxia, dysmetria, and diplopia in the context of viral febrile illnesses, even if there is no history of seizures. While there are clinical and molecular data suggesting that SCN8A dysfunction can cause temperature-sensitive phenotypes, further research is necessary to determine how the functional changes caused by our patient's SCN8A variant result in her unique phenotype.
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Affiliation(s)
- Alexandra Laliberté
- From the Faculty of Medicine and Health Sciences (A.L.), McGill University; and Research Institute of the McGill University Medical Centre (K.A.M.), Montreal, Quebec, Canada
| | - Kenneth A Myers
- From the Faculty of Medicine and Health Sciences (A.L.), McGill University; and Research Institute of the McGill University Medical Centre (K.A.M.), Montreal, Quebec, Canada
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8
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Hu A, Zhao R, Ren B, Li Y, Lu J, Tai Y. Projection-Specific Heterogeneity of the Axon Initial Segment of Pyramidal Neurons in the Prelimbic Cortex. Neurosci Bull 2023; 39:1050-1068. [PMID: 36849716 PMCID: PMC10313623 DOI: 10.1007/s12264-023-01038-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 11/22/2022] [Indexed: 03/01/2023] Open
Abstract
The axon initial segment (AIS) is a highly specialized axonal compartment where the action potential is initiated. The heterogeneity of AISs has been suggested to occur between interneurons and pyramidal neurons (PyNs), which likely contributes to their unique spiking properties. However, whether the various characteristics of AISs can be linked to specific PyN subtypes remains unknown. Here, we report that in the prelimbic cortex (PL) of the mouse, two types of PyNs with axon projections either to the contralateral PL or to the ipsilateral basal lateral amygdala, possess distinct AIS properties reflected by morphology, ion channel expression, action potential initiation, and axo-axonic synaptic inputs from chandelier cells. Furthermore, projection-specific AIS diversity is more prominent in the superficial layer than in the deep layer. Thus, our study reveals the cortical layer- and axon projection-specific heterogeneity of PyN AISs, which may endow the spiking of various PyN types with exquisite modulation.
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Affiliation(s)
- Ankang Hu
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China
- School of Clinical Medicine, Fudan University, Shanghai, 200032, China
| | - Rui Zhao
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Baihui Ren
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yang Li
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Jiangteng Lu
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
- Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai, 201210, China.
| | - Yilin Tai
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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9
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Structure of human Na V1.6 channel reveals Na + selectivity and pore blockade by 4,9-anhydro-tetrodotoxin. Nat Commun 2023; 14:1030. [PMID: 36823201 PMCID: PMC9950489 DOI: 10.1038/s41467-023-36766-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 02/15/2023] [Indexed: 02/25/2023] Open
Abstract
The sodium channel NaV1.6 is widely expressed in neurons of the central and peripheral nervous systems, which plays a critical role in regulating neuronal excitability. Dysfunction of NaV1.6 has been linked to epileptic encephalopathy, intellectual disability and movement disorders. Here we present cryo-EM structures of human NaV1.6/β1/β2 alone and complexed with a guanidinium neurotoxin 4,9-anhydro-tetrodotoxin (4,9-ah-TTX), revealing molecular mechanism of NaV1.6 inhibition by the blocker. The apo-form structure reveals two potential Na+ binding sites within the selectivity filter, suggesting a possible mechanism for Na+ selectivity and conductance. In the 4,9-ah-TTX bound structure, 4,9-ah-TTX binds to a pocket similar to the tetrodotoxin (TTX) binding site, which occupies the Na+ binding sites and completely blocks the channel. Molecular dynamics simulation results show that subtle conformational differences in the selectivity filter affect the affinity of TTX analogues. Taken together, our results provide important insights into NaV1.6 structure, ion conductance, and inhibition.
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10
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Kumari PL, Rajamohanan K, Krishnan ASA. Risk Factors of First Episode Simple Febrile Seizures in Children Aged 6 Month to 5 Year: A Case Control Study. Indian Pediatr 2022. [DOI: 10.1007/s13312-022-2646-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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A dynamics model of neuron-astrocyte network accounting for febrile seizures. Cogn Neurodyn 2021; 16:411-423. [PMID: 35401866 PMCID: PMC8934847 DOI: 10.1007/s11571-021-09706-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 06/03/2021] [Accepted: 07/17/2021] [Indexed: 10/20/2022] Open
Abstract
Febrile seizure (FS) is a full-body convulsion caused by a high body temperature that affect young kids, however, how these most common of human seizures are generated by fever has not been known. One common observation is that cortical neurons become overexcited with abnormal running of sodium and potassium ions cross membrane in raised body temperature condition, Considering that astrocyte Kir4.1 channel play a critical role in maintaining extracellular homeostasis of ionic concentrations and electrochemical potentials of neurons by fast depletion of extracellular potassium ions, we examined here the potential role of temperature-dependent Kir4.1 channel in astrocytes in causing FS. We first built up a temperature-dependent computational model of the Kir4.1 channel in astrocytes and validated with experiments. We have then built up a neuron-astrocyte network and examine the role of the Kir4.1 channel in modulating neuronal firing dynamics as temperature increase. The numerical experiment demonstrated that the Kir4.1 channel function optimally in the body temperature around 37 °C in cleaning 'excessive' extracellular potassium ions during neuronal firing process, however, higher temperature deteriorates its cleaning function, while lower temperature slows down its cleaning efficiency. With the increase of temperature, neurons go through different stages of spiking dynamics from spontaneous slow oscillations, to tonic spiking, fast bursting oscillations, and eventually epileptic bursting. Thus, our study may provide a potential new mechanism that febrile seizures may be happened due to temperature-dependent functional disorders of Kir4.1 channel in astrocytes. Supplementary Information The online version contains supplementary material available at 10.1007/s11571-021-09706-w.
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12
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Thompson CH, Ben-Shalom R, Bender KJ, George AL. Alternative splicing potentiates dysfunction of early-onset epileptic encephalopathy SCN2A variants. J Gen Physiol 2021; 152:133672. [PMID: 31995133 PMCID: PMC7054859 DOI: 10.1085/jgp.201912442] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 01/07/2020] [Indexed: 01/06/2023] Open
Abstract
Epileptic encephalopathies are severe forms of infantile-onset epilepsy often complicated by severe neurodevelopmental impairments. Some forms of early-onset epileptic encephalopathy (EOEE) have been associated with variants in SCN2A, which encodes the brain voltage-gated sodium channel NaV1.2. Many voltage-gated sodium channel genes, including SCN2A, undergo developmentally regulated mRNA splicing. The early onset of these disorders suggests that developmentally regulated alternative splicing of NaV1.2 may be an important consideration when elucidating the pathophysiological consequences of epilepsy-associated variants. We hypothesized that EOEE-associated NaV1.2 variants would exhibit greater dysfunction in a splice isoform that is prominently expressed during early development. We engineered five EOEE-associated NaV1.2 variants (T236S, E999K, S1336Y, T1623N, and R1882Q) into the adult and neonatal splice isoforms of NaV1.2 and performed whole-cell voltage clamp to elucidate their functional properties. All variants exhibited functional defects that could enhance neuronal excitability. Three of the five variants (T236S, E999K, and S1336Y) exhibited greater dysfunction in the neonatal isoform compared with those observed in the adult isoform. Computational modeling of a developing cortical pyramidal neuron indicated that T236S, E999K, S1336Y, and R1882Q showed hyperexcitability preferentially in immature neurons. These results suggest that both splice isoform and neuronal developmental stage influence how EOEE-associated NaV1.2 variants affect neuronal excitability.
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Affiliation(s)
- Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Roy Ben-Shalom
- Center for Integrative Neuroscience, Kavli Institute for Fundamental Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA
| | - Kevin J Bender
- Center for Integrative Neuroscience, Kavli Institute for Fundamental Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
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13
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Hippocampal astrocytic neogenin regulating glutamate uptake, a critical pathway for preventing epileptic response. Proc Natl Acad Sci U S A 2021; 118:2022921118. [PMID: 33850017 DOI: 10.1073/pnas.2022921118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Epilepsy, a common neurological disorder, is featured with recurrent seizures. Its underlying pathological mechanisms remain elusive. Here, we provide evidence for loss of neogenin (NEO1), a coreceptor for multiple ligands, including netrins and bone morphological proteins, in the development of epilepsy. NEO1 is reduced in hippocampi from patients with epilepsy based on transcriptome and proteomic analyses. Neo1 knocking out (KO) in mouse brains displays elevated epileptiform spikes and seizure susceptibility. These phenotypes were undetectable in mice, with selectively depleted NEO1 in excitatory (NeuroD6-Cre+) or inhibitory (parvalbumin+) neurons, but present in mice with specific hippocampal astrocytic Neo1 KO. Additionally, neurons in hippocampal dentate gyrus, a vulnerable region in epilepsy, in mice with astrocyte-specific Neo1 KO show reductions in inhibitory synaptic vesicles and the frequency of miniature inhibitory postsynaptic current(mIPSC), but increase of the duration of miniature excitatory postsynaptic current and tonic NMDA receptor currents, suggesting impairments in both GABAergic transmission and extracellular glutamate clearance. Further proteomic and cell biological analyses of cell-surface proteins identified GLAST, a glutamate-aspartate transporter that is marked reduced in Neo1 KO astrocytes and the hippocampus. NEO1 interacts with GLAST and promotes GLAST surface distribution in astrocytes. Expressing NEO1 or GLAST in Neo1 KO astrocytes in the hippocampus abolishes the epileptic phenotype. Taken together, these results uncover an unrecognized pathway of NEO1-GLAST in hippocampal GFAP+ astrocytes, which is critical for GLAST surface distribution and function, and GABAergic transmission, unveiling NEO1 as a valuable therapeutic target to protect the brain from epilepsy.
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14
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Stefano M, Cordella F, Loppini A, Filippi S, Zollo L. A Multiscale Approach to Axon and Nerve Stimulation Modeling: A Review. IEEE Trans Neural Syst Rehabil Eng 2021; 29:397-407. [PMID: 33497336 DOI: 10.1109/tnsre.2021.3054551] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Electrical nerve fiber stimulation is a technique widely used in prosthetics and rehabilitation, and its study from a computational point of view can be a useful instrument to support experimental tests. In the last years, there was an increasing interest in computational modeling of neural cells and numerical simulations on nerve fibers stimulation because of its usefulness in forecasting the effect of electrical current stimuli delivered to tissues through implanted electrodes, in the design of optimal stimulus waveforms based on the specific application (i.e., inducing limb movements, sensory feedback or physiological function restoring), and in the evaluation of the current stimuli properties according to the characteristics of the nerves surrounding tissue. Therefore, a review study on the main modeling and computational frameworks adopted to investigate peripheral nerve stimulation is an important instrument to support and drive future research works. To this aim, this paper deals with mathematical models of neural cells with a detailed description of ion channels and numerical simulations using finite element methods to describe the dynamics of electrical stimulation by implanted electrodes in peripheral nerve fibers. In particular, we evaluate different nerve cell models considering different ion channels present in neurons and provide a guideline on multiscale numerical simulations of electrical nerve fibers stimulation.
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15
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Karahuseyinoglu S, Sekerdag E, Aria MM, Cetin Tas Y, Nizamoglu S, Solaroglu I, Gürsoy-Özdemir Y. Three-dimensional neuron-astrocyte construction on matrigel enhances establishment of functional voltage-gated sodium channels. J Neurochem 2020; 156:848-866. [PMID: 32939791 DOI: 10.1111/jnc.15185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/14/2020] [Accepted: 09/04/2020] [Indexed: 11/28/2022]
Abstract
This study aimed to investigate and compare cell growth manners and functional differences of primary cortical neurons cultured on either poly-d-lysine (PDL) and or Matrigel, to delineate the role of extracellular matrix on providing resemblance to in vivo cellular interactions in nervous tissue. Primary cortical neurons, obtained from embryonic day 15 mice pups, seeded either on PDL- or Matrigel-coated culture ware were investigated by DIC/bright field and fluorescence/confocal microscopy for their morphology, 2D and 3D structure, and distribution patterns. Patch clamp, western blot, and RT-PCR studies were performed to investigate neuronal firing thresholds and sodium channel subtypes Nav1.2 and Nav1.6 expression. Cortical neurons cultured on PDL coating possessed a 2D structure composed of a few numbers of branched and tortuous neurites that contacted with each other in one to one manner, however, neurons on Matrigel coating showed a more complicated dimensional network that depicted tight, linear axonal bundles forming a 3D interacted neuron-astrocyte construction. This difference in growth patterns also showed a significant alteration in neuronal firing threshold which was recorded between 80 < Iinj > 120 pA on PDL and 2 < Iinj > 160 pA on Matrigel. Neurons grown up on Matrigel showed increased levels of sodium channel protein expression of Nav1.2 and Nav1.6 compared to neurons on PDL. These results have demonstrated that a 3D interacted neuron-astrocyte construction on Matrigel enhances the development of Nav1.2 and Nav1.6 in vitro and decreases neuronal firing threshold by 40 times compared to conventional PDL, resembling in vivo neuronal networks and hence would be a better in vitro model of adult neurons.
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Affiliation(s)
- Sercin Karahuseyinoglu
- Department of Histology and Embryology, School of Medicine, Koç University, Istanbul, Turkey
| | - Emine Sekerdag
- Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey
| | | | - Yagmur Cetin Tas
- Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey
| | - Sedat Nizamoglu
- Department of Electrical and Electronics Engineering, Koç University, Istanbul, Turkey
| | - Ihsan Solaroglu
- Department of Neurosurgery, School of Medicine, Koç University, Istanbul, Turkey.,Department of Basic Science, Loma Linda University, Loma Linda, CA, USA
| | - Yasemin Gürsoy-Özdemir
- Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey.,Department of Neurology, School of Medicine, Koç University, Istanbul, Turkey
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16
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Chow CY, Absalom N, Biggs K, King GF, Ma L. Venom-derived modulators of epilepsy-related ion channels. Biochem Pharmacol 2020; 181:114043. [PMID: 32445870 DOI: 10.1016/j.bcp.2020.114043] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/18/2020] [Indexed: 12/18/2022]
Abstract
Epilepsy is characterised by spontaneous recurrent seizures that are caused by an imbalance between neuronal excitability and inhibition. Since ion channels play fundamental roles in the generation and propagation of action potentials as well as neurotransmitter release at a subset of excitatory and inhibitory synapses, their dysfunction has been linked to a wide variety of epilepsies. Indeed, these unique proteins are the major biological targets for antiepileptic drugs. Selective targeting of a specific ion channel subtype remains challenging for small molecules, due to the high level of homology among members of the same channel family. As a consequence, there is a growing trend to target ion channels with biologics. Venoms are the best known natural source of ion channel modulators, and venom peptides are increasingly recognised as potential therapeutics due to their high selectivity and potency gained through millions of years of evolutionary selection pressure. Here we describe the major ion channel families involved in the pathogenesis of various types of epilepsy, including voltage-gated Na+, K+, Ca2+ channels, Cys-loop receptors, ionotropic glutamate receptors and P2X receptors, and currently available venom-derived peptides that target these channel proteins. Although only a small number of venom peptides have successfully progressed to the clinic, there is reason to be optimistic about their development as antiepileptic drugs, notwithstanding the challenges associated with development of any class of peptide drug.
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Affiliation(s)
- Chun Yuen Chow
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nathan Absalom
- Brain and Mind Centre, School of Pharmacy, Faculty of Health and Medicine, The University of Sydney, Sydney, NSW 2050, Australia
| | - Kimberley Biggs
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Linlin Ma
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia.
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17
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Van Hook MJ. Temperature effects on synaptic transmission and neuronal function in the visual thalamus. PLoS One 2020; 15:e0232451. [PMID: 32353050 PMCID: PMC7192487 DOI: 10.1371/journal.pone.0232451] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/15/2020] [Indexed: 12/11/2022] Open
Abstract
Numerous neuronal properties including the synaptic vesicle release process, neurotransmitter receptor complement, and postsynaptic ion channels are involved in transforming synaptic inputs into postsynaptic spiking. Temperature is a significant influencer of neuronal function and synaptic integration. Changing temperature can affect neuronal physiology in a diversity of ways depending on how it affects different members of the cell’s ion channel complement. Temperature’s effects on neuronal function are critical for pathological states such as fever, which can trigger seizure activity, but are also important in interpreting and comparing results of experiments conducted at room vs physiological temperature. The goal of this study was to examine the influence of temperature on synaptic properties and ion channel function in thalamocortical (TC) relay neurons in acute brain slices of the dorsal lateral geniculate nucleus, a key synaptic target of retinal ganglion cells in the thalamus. Warming the superfusate in patch clamp experiments with acutely-prepared brain slices led to an overall inhibition of synaptically-driven spiking behavior in TC neurons in response to a retinal ganglion cell spike train. Further study revealed that this was associated with an increase in presynaptic synaptic vesicle release probability and synaptic depression and altered passive and active membrane properties. Additionally, warming the superfusate triggered activation of an inwardly rectifying potassium current and altered the voltage-dependence of voltage-gated Na+ currents and T-type calcium currents. This study highlights the importance of careful temperature control in ex vivo physiological experiments and illustrates how numerous properties such as synaptic inputs, active conductances, and passive membrane properties converge to determine spike output.
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Affiliation(s)
- Matthew J. Van Hook
- Department of Ophthalmology & Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America
- * E-mail: ,
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18
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Piarroux J, Riant F, Humbertclaude V, Remerand G, Hadjadj J, Rejou F, Coubes C, Pinson L, Meyer P, Roubertie A. FGF14-related episodic ataxia: delineating the phenotype of Episodic Ataxia type 9. Ann Clin Transl Neurol 2020; 7:565-572. [PMID: 32162847 PMCID: PMC7187715 DOI: 10.1002/acn3.51005] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 11/09/2022] Open
Abstract
We report four patients from two families who presented attacks of childhood-onset episodic ataxia associated with pathogenic mutations in the FGF14 gene. Attacks were triggered by fever, lasted several days, and had variable frequencies. Nystagmus and/or postural tremor and/or learning disabilities were noticed in individuals harboring FGF14 mutation with or without episodic ataxia. These cases and literature data delineate the FGF14-mutation-related episodic ataxia phenotype: wide range of age at onset (from childhood to adulthood), variable durations and frequencies, triggering factors including fever, and association to chronic symptoms. We propose to add FGF14-related episodic ataxia to the list of primary episodic ataxia as Episodic Ataxia type 9.
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Affiliation(s)
- Julie Piarroux
- Département de Neuropédiatrie, CHU Gui de Chauliac, Montpellier, France
| | - Florence Riant
- Service de Génétique Moléculaire Neurovasculaire, Groupe hospitalier Saint-Louis - Lariboisière - Fernand Widal AP-HP, Paris, France
| | - Véronique Humbertclaude
- Service de Médecine Psychologique Enfants et Adolescents, CHU Saint Eloi, Montpellier, France
| | | | - Jessica Hadjadj
- Service de Génétique Moléculaire Neurovasculaire, Groupe hospitalier Saint-Louis - Lariboisière - Fernand Widal AP-HP, Paris, France
| | - Franck Rejou
- Département de Neuropédiatrie, CHU Gui de Chauliac, Montpellier, France
| | - Christine Coubes
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Lucile Pinson
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Pierre Meyer
- Département de Neuropédiatrie, CHU Gui de Chauliac, Montpellier, France.,PhyMedExp, U1046 INSERM, UMR9214 CNRS, Montpellier, France
| | - Agathe Roubertie
- Département de Neuropédiatrie, CHU Gui de Chauliac, Montpellier, France.,INSERM U 1051, Institut des Neurosciences de Montpellier, Montpellier, France
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19
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Weuring WJ, Singh S, Volkers L, Rook MB, van ‘t Slot RH, Bosma M, Inserra M, Vetter I, Verhoeven-Duif NM, Braun KPJ, Rivara M, Koeleman BPC. NaV1.1 and NaV1.6 selective compounds reduce the behavior phenotype and epileptiform activity in a novel zebrafish model for Dravet Syndrome. PLoS One 2020; 15:e0219106. [PMID: 32134913 PMCID: PMC7058281 DOI: 10.1371/journal.pone.0219106] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 02/04/2020] [Indexed: 12/03/2022] Open
Abstract
Dravet syndrome is caused by dominant loss-of-function mutations in SCN1A which cause reduced activity of Nav1.1 leading to lack of neuronal inhibition. On the other hand, gain-of-function mutations in SCN8A can lead to a severe epileptic encephalopathy subtype by over activating NaV1.6 channels. These observations suggest that Nav1.1 and Nav1.6 represent two opposing sides of the neuronal balance between inhibition and activation. Here, we hypothesize that Dravet syndrome may be treated by either enhancing Nav1.1 or reducing Nav1.6 activity. To test this hypothesis we generated and characterized a novel DS zebrafish model and tested new compounds that selectively activate or inhibit the human NaV1.1 or NaV1.6 channel respectively. We used CRISPR/Cas9 to generate two separate Scn1Lab knockout lines as an alternative to previous zebrafish models generated by random mutagenesis or morpholino oligomers. Using an optimized locomotor assay, spontaneous burst movements were detected that were unique to Scn1Lab knockouts and disappear when introducing human SCN1A mRNA. Besides the behavioral phenotype, Scn1Lab knockouts show sudden, electrical discharges in the brain that indicate epileptic seizures in zebrafish. Scn1Lab knockouts showed increased sensitivity to the GABA antagonist pentylenetetrazole and a reduction in whole organism GABA levels. Drug screenings further validated a Dravet syndrome phenotype. We tested the NaV1.1 activator AA43279 and two novel NaV1.6 inhibitors MV1369 and MV1312 in the Scn1Lab knockouts. Both type of compounds significantly reduced the number of spontaneous burst movements and seizure activity. Our results show that selective inhibition of NaV1.6 could be just as efficient as selective activation of NaV1.1 and these approaches could prove to be novel potential treatment strategies for Dravet syndrome and other (genetic) epilepsies. Compounds tested in zebrafish however, should always be further validated in other model systems for efficacy in mammals and to screen for potential side effects.
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Affiliation(s)
- Wout J. Weuring
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Sakshi Singh
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Linda Volkers
- Department of Cardiology, Laboratory of Experimental Cardiology, University Medical Centre Leiden, Leiden, the Netherlands
| | - Martin B. Rook
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Ruben H. van ‘t Slot
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Marjolein Bosma
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Marco Inserra
- Centre for Pain Research & School of Pharmacy, University of Queensland, Brisbane, Australia
| | - Irina Vetter
- Centre for Pain Research & School of Pharmacy, University of Queensland, Brisbane, Australia
| | - Nanda M. Verhoeven-Duif
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Kees P. J. Braun
- Department of Neurology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Mirko Rivara
- Food and Drug Department, University of Parma, Parma, Italy
| | - Bobby P. C. Koeleman
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
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20
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Toh MF, Brooks JM, Strassmaier T, Haedo RJ, Puryear CB, Roth BL, Ouk K, Pin SS. Application of High-Throughput Automated Patch-Clamp Electrophysiology to Study Voltage-Gated Ion Channel Function in Primary Cortical Cultures. SLAS DISCOVERY 2020; 25:447-457. [PMID: 32003306 DOI: 10.1177/2472555220902388] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Conventionally, manual patch-clamp electrophysiological approaches are the gold standard for studying ion channel function in neurons. However, these approaches are labor-intensive, yielding low-throughput results, and are therefore not amenable for compound profiling efforts during the early stages of drug discovery. The SyncroPatch 384PE has been successfully implemented for pharmacological experiments in heterologous overexpression systems that may not reproduce the function of voltage-gated ion channels in a native, heterogeneous environment. Here, we describe a protocol allowing the characterization of endogenous voltage-gated potassium (Kv) and sodium (Nav) channel function in developing primary rat cortical cultures, allowing investigations at a significantly improved throughput compared with manual approaches. Key neuronal marker expression and microelectrode array recordings of electrophysiological activity over time correlated well with neuronal maturation. Gene expression data revealed high molecular diversity in Kv and Nav subunit composition throughout development. Voltage-clamp experiments elicited three major current components composed of inward and outward conductances. Further pharmacological experiments confirmed the endogenous expression of functional Kv and Nav channels in primary cortical neurons. The major advantages of this approach compared with conventional manual patch-clamp systems include unprecedented improvements in experimental ease and throughput for ion channel research in primary neurons. These efforts demonstrated feasibility for primary neuronal ion channel investigation with the SyncroPatch, providing the foundation for future studies characterizing biophysical changes in endogenous ion channels in primary systems associated with disease or development.
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21
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Inglis GAS, Wong JC, Butler KM, Thelin JT, Mistretta OC, Wu X, Lin X, English AW, Escayg A. Mutations in the Scn8a DIIS4 voltage sensor reveal new distinctions among hypomorphic and null Na v 1.6 sodium channels. GENES BRAIN AND BEHAVIOR 2019; 19:e12612. [PMID: 31605437 DOI: 10.1111/gbb.12612] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/30/2019] [Accepted: 09/22/2019] [Indexed: 12/14/2022]
Abstract
Mutations in the voltage-gated sodium channel gene SCN8A cause a broad range of human diseases, including epilepsy, intellectual disability, and ataxia. Here we describe three mouse lines on the C57BL/6J background with novel, overlapping mutations in the Scn8a DIIS4 voltage sensor: an in-frame 9 bp deletion (Δ9), an in-frame 3 bp insertion (∇3) and a 35 bp deletion that results in a frameshift and the generation of a null allele (Δ35). Scn8a Δ9/+ and Scn8a ∇3/+ heterozygous mutants display subtle motor deficits, reduced acoustic startle response, and are resistant to induced seizures, suggesting that these mutations reduce activity of the Scn8a channel protein, Nav 1.6. Heterozygous Scn8a Δ35/+ mutants show no alterations in motor function or acoustic startle response, but are resistant to induced seizures. Homozygous mutants from each line exhibit premature lethality and severe motor impairments, ranging from uncoordinated gait with tremor (Δ9 and ∇3) to loss of hindlimb control (Δ35). Scn8a Δ9/Δ9 and Scn8a ∇3/∇3 homozygous mutants also exhibit impaired nerve conduction velocity, while normal nerve conduction was observed in Scn8a Δ35/Δ35 homozygous mice. Our results suggest that hypomorphic mutations that reduce Nav 1.6 activity will likely result in different clinical phenotypes compared to null alleles. These three mouse lines represent a valuable opportunity to examine the phenotypic impacts of hypomorphic and null Scn8a mutations without the confound of strain-specific differences.
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Affiliation(s)
| | - Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, Georgia
| | - Kameryn M Butler
- Department of Human Genetics, Emory University, Atlanta, Georgia
| | | | | | - Xuewen Wu
- Department of Cell Biology, Emory University, Atlanta, Georgia.,Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia
| | - Xi Lin
- Department of Cell Biology, Emory University, Atlanta, Georgia.,Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia
| | | | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, Georgia
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22
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Nadella RK, Chellappa A, Subramaniam AG, More RP, Shetty S, Prakash S, Ratna N, Vandana VP, Purushottam M, Saini J, Viswanath B, Bindu PS, Nagappa M, Mehta B, Jain S, Kannan R. Identification and functional characterization of two novel mutations in KCNJ10 and PI4KB in SeSAME syndrome without electrolyte imbalance. Hum Genomics 2019; 13:53. [PMID: 31640787 PMCID: PMC6805350 DOI: 10.1186/s40246-019-0236-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 08/23/2019] [Indexed: 12/27/2022] Open
Abstract
Background Dysfunction in inwardly rectifying potassium channel Kir4.1 has been implicated in SeSAME syndrome, an autosomal-recessive (AR), rare, multi-systemic disorder. However, not all neurological, intellectual disability, and comorbid phenotypes in SeSAME syndrome can be mechanistically linked solely to Kir4.1 dysfunction. Methods We therefore performed whole-exome sequencing and identified additional genetic risk-elements that might exert causative effects either alone or in concert with Kir4.1 in a family diagnosed with SeSAME syndrome. Results Two variant prioritization pipelines based on AR inheritance and runs of homozygosity (ROH), identified two novel homozygous variants in KCNJ10 and PI4KB and five rare homozygous variants in PVRL4, RORC, FLG2, FCRL1, NIT1 and one common homozygous variant in HSPA6 segregating in all four patients. The novel mutation in KCNJ10 resides in the cytoplasmic domain of Kir4.1, a seat of phosphatidylinositol bisphosphate (PIP2) binding. The mutation altered the subcellular localization and stability of Kir4.1 in patient-specific lymphoblastoid cells (LCLs) compared to parental controls. Barium-sensitive endogenous K+ currents in patient-specific LCLs using whole-cell patch-clamp electrophysiology revealed membrane depolarization and defects in inward K+ ion conductance across the membrane, thereby suggesting a loss-of-function effect of KCNJ10 variant. Conclusion Altogether, our findings implicate the role of new genes in SeSAME syndrome without electrolyte imbalance and thereby speculate the regulation of Kir4.1 channel activity by PIP2 and integrin-mediated adhesion signaling mechanisms. Electronic supplementary material The online version of this article (10.1186/s40246-019-0236-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ravi K Nadella
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India
| | - Anirudh Chellappa
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India
| | - Anand G Subramaniam
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India
| | - Ravi Prabhakar More
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
| | - Srividya Shetty
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India
| | - Suriya Prakash
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India
| | - Nikhil Ratna
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India
| | - V P Vandana
- Department of Speech Pathology and Audiology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Meera Purushottam
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India
| | - Jitender Saini
- Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Biju Viswanath
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India
| | - P S Bindu
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Madhu Nagappa
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Bhupesh Mehta
- Department of Biophysics, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Sanjeev Jain
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India.,National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
| | - Ramakrishnan Kannan
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India.
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23
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Yang J, Xiao Y, Li L, He Q, Li M, Shu Y. Biophysical Properties of Somatic and Axonal Voltage-Gated Sodium Channels in Midbrain Dopaminergic Neurons. Front Cell Neurosci 2019; 13:317. [PMID: 31354436 PMCID: PMC6636218 DOI: 10.3389/fncel.2019.00317] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/27/2019] [Indexed: 01/14/2023] Open
Abstract
Spiking activities of midbrain dopaminergic neurons are critical for key brain functions including motor control and affective behaviors. Voltage-gated Na+ channels determine neuronal excitability and action potential (AP) generation. Previous studies on dopaminergic neuron excitability mainly focused on Na+ channels at the somatodendritic compartments. Properties of axonal Na+ channels, however, remain largely unknown. Using patch-clamp recording from somatic nucleated patches and isolated axonal blebs from the axon initial segment (AIS) of dopaminergic neurons in mouse midbrain slices, we found that AIS channel density is approximately 4–9 fold higher than that at the soma. Similar voltage dependence of channel activation and inactivation was observed between somatic and axonal channels in both SNc and VTA cells, except that SNc somatic channels inactivate at more hyperpolarized membrane potentials (Vm). In both SNc and VTA, axonal channels take longer time to inactivate at a subthreshold depolarization Vm level, but are faster to recover from inactivation than somatic channels. Moreover, we found that immunosignals of Nav1.2 accumulate at the AIS of dopaminergic neurons. In contrast, Nav1.1 and Nav1.6 immunosignals are not detectible. Together, our results reveal a high density of Na+ channels at the AIS and their molecular identity. In general, somatic and axonal channels of both SNc and VTA dopaminergic neurons share similar biophysical properties. The relatively delayed inactivation onset and faster recovery from inactivation of axonal Na+ channels may ensure AP initiation at high frequencies and faithful signal conduction along the axon.
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Affiliation(s)
- Jun Yang
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Yujie Xiao
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Liang Li
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Quansheng He
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Min Li
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Yousheng Shu
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
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24
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Saez NJ, Herzig V. Versatile spider venom peptides and their medical and agricultural applications. Toxicon 2018; 158:109-126. [PMID: 30543821 DOI: 10.1016/j.toxicon.2018.11.298] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 11/12/2018] [Accepted: 11/14/2018] [Indexed: 02/07/2023]
Abstract
Spiders have been evolving complex and diverse repertoires of peptides in their venoms with vast pharmacological activities for more than 300 million years. Spiders use their venoms for prey capture and defense, hence they contain peptides that target both prey (mainly arthropods) and predators (other arthropods or vertebrates). This includes peptides that potently and selectively modulate a range of targets such as ion channels, receptors and signaling pathways involved in physiological processes. The contribution of these targets in particular disease pathophysiologies makes spider venoms a valuable source of peptides with potential therapeutic use. In addition, peptides with insecticidal activities, used for prey capture, can be exploited for the development of novel bioinsecticides for agricultural use. Although we have already reviewed potential applications of spider venom peptides as therapeutics (in 2010) and as bioinsecticides (in 2012), a considerable number of research articles on both topics have been published since, warranting an updated review. Here we explore the most recent research on the use of spider venom peptides for both medical and agricultural applications.
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Affiliation(s)
- Natalie J Saez
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Volker Herzig
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
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25
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Ogiwara I, Miyamoto H, Tatsukawa T, Yamagata T, Nakayama T, Atapour N, Miura E, Mazaki E, Ernst SJ, Cao D, Ohtani H, Itohara S, Yanagawa Y, Montal M, Yuzaki M, Inoue Y, Hensch TK, Noebels JL, Yamakawa K. Nav1.2 haplodeficiency in excitatory neurons causes absence-like seizures in mice. Commun Biol 2018; 1:96. [PMID: 30175250 PMCID: PMC6115194 DOI: 10.1038/s42003-018-0099-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Mutations in the SCN2A gene encoding a voltage-gated sodium channel Nav1.2 are associated with epilepsies, intellectual disability, and autism. SCN2A gain-of-function mutations cause early-onset severe epilepsies, while loss-of-function mutations cause autism with milder and/or later-onset epilepsies. Here we show that both heterozygous Scn2a-knockout and knock-in mice harboring a patient-derived nonsense mutation exhibit ethosuximide-sensitive absence-like seizures associated with spike-and-wave discharges at adult stages. Unexpectedly, identical seizures are reproduced and even more prominent in mice with heterozygous Scn2a deletion specifically in dorsal-telencephalic (e.g., neocortical and hippocampal) excitatory neurons, but are undetected in mice with selective Scn2a deletion in inhibitory neurons. In adult cerebral cortex of wild-type mice, most Nav1.2 is expressed in excitatory neurons with a steady increase and redistribution from proximal (i.e., axon initial segments) to distal axons. These results indicate a pivotal role of Nav1.2 haplodeficiency in excitatory neurons in epilepsies of patients with SCN2A loss-of-function mutations.
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Affiliation(s)
- Ikuo Ogiwara
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Department of Physiology, Nippon Medical School, Tokyo, 113-8602, Japan
| | - Hiroyuki Miyamoto
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Laboratory for Neuronal Circuit Development, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,PRESTO, Japan Science and Technology Agency, Saitama, 332-0012, Japan
| | - Tetsuya Tatsukawa
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Tetsushi Yamagata
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Tojo Nakayama
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Department of Pediatrics, Tohoku University School of Medicine, Sendai, 980-8574, Japan.,Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Nafiseh Atapour
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Laboratory for Neuronal Circuit Development, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, VIC, 3050, Australia
| | - Eriko Miura
- Department of Physiology, School of Medicine, Keio University, Tokyo, 160-8582, Japan
| | - Emi Mazaki
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Sara J Ernst
- Department of Neurology, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Dezhi Cao
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, 420-8688, Japan.,Neurology Department, Shenzhen Children's Hospital, 518026, Guangdong, China
| | - Hideyuki Ohtani
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, 420-8688, Japan
| | - Shigeyoshi Itohara
- Laboratory for Behavioral Genetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,FIRST, Japan Science and Technology Agency, Saitama, 332-0012, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, 371-8511, Japan.,CREST, Japan Science and Technology Agency, Saitama, 332-0012, Japan
| | - Mauricio Montal
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Michisuke Yuzaki
- Department of Physiology, School of Medicine, Keio University, Tokyo, 160-8582, Japan
| | - Yushi Inoue
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, 420-8688, Japan
| | - Takao K Hensch
- Laboratory for Neuronal Circuit Development, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA.,Department of Neurology, FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jeffrey L Noebels
- Department of Neurology, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.
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26
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Leung AK, Hon KL, Leung TN. Febrile seizures: an overview. Drugs Context 2018; 7:212536. [PMID: 30038660 PMCID: PMC6052913 DOI: 10.7573/dic.212536] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/16/2018] [Accepted: 06/19/2018] [Indexed: 12/14/2022] Open
Abstract
Background Febrile seizures are the most common neurologic disorder in childhood. Physicians should be familiar with the proper evaluation and management of this common condition. Objective To provide an update on the current understanding, evaluation, and management of febrile seizures. Methods A PubMed search was completed in Clinical Queries using the key terms ‘febrile convulsions’ and ‘febrile seizures’. The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews. Results Febrile seizures, with a peak incidence between 12 and 18 months of age, likely result from a vulnerability of the developing central nervous system to the effects of fever, in combination with an underlying genetic predisposition and environmental factors. The majority of febrile seizures occur within 24 hours of the onset of the fever. Febrile seizures can be simple or complex. Clinical judgment based on variable presentations must direct the diagnostic studies which are usually not necessary in the majority of cases. A lumbar puncture should be considered in children younger than 12 months of age or with suspected meningitis. Children with complex febrile seizures are at risk of subsequent epilepsy. Approximately 30–40% of children with a febrile seizure will have a recurrence during early childhood. The prognosis is favorable as the condition is usually benign and self-limiting. Intervention to stop the seizure often is unnecessary. Conclusion Continuous preventative antiepileptic therapy for the prevention of recurrent febrile seizures is not recommended. The use of intermittent anticonvulsant therapy is not routinely indicated. Antipyretics have no role in the prevention of febrile seizures.
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Affiliation(s)
- Alexander Kc Leung
- Department of Pediatrics, The University of Calgary, Alberta Children's Hospital, Calgary, Alberta, Canada
| | - Kam Lun Hon
- Department of Pediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Theresa Nh Leung
- Department of Pediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
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