Pathomechanisms of SCN3A-related neurodevelopmental disorder

SCN3A相关神经发育障碍的发病机制

• 批准号: 10544490
• 负责人: ETHAN M GOLDBERG
• 金额: $ 52.83万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-01 至 2025-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10544490
• 关键词: Acceleration; Acute; Alleles; Anticonvulsants; Biological Models; Biophysics; Birth; Brain; CRISPR correction; CRISPR/Cas technology; Calcium; Cell Line; Cells; Cerebral cortex; Chronic; Clinical; Cortical Malformation; Data; Defect; Dependence; Development; Disease; Electrophysiology (science); Electroporation; Embryo; Epilepsy; Exhibits; Functional disorder; Gene Mutation; Genes; Genetic Variation; Heterozygote; Human; Immunohistochemistry; Impairment; In Vitro; Inherited; Intellectual functioning disability; Ion Channel; Knock-in Mouse; Lead; Link; LoxP-flanked allele; Maps; Mediating; Membrane Potentials; Modeling; Morphology; Mus; Mutant Strains Mice; Neurites; Neurodevelopmental Disability; Neurodevelopmental Disorder; Neurons; Neurosciences; Pathogenicity; Pathologic; Pathology; Patients; Pharmacology; Physiology; Placenta; Pre-Clinical Model; Prevention; Preventive measure; Preventive therapy; Property; Prosencephalon; Registries; Research; Resistance; Role; Severities; Severity of illness; Slice; Sodium; Sodium Channel; System; Testing; Time; Translating; Variant; biophysical properties; brain malformation; channel blockers; clinical application; clinical phenotype; cohort; experimental study; gain of function; genetic variant; human disease; human stem cells; in utero; induced pluripotent stem cell; innovation; loss of function; malformation in cortical development; migration; mouse model; mutant; neuronal excitability; novel; novel therapeutics; overexpression; pharmacologic; postnatal; pregnant; prevent; pup; severe intellectual disability; targeted treatment; tool; variant of unknown significance; voltage; voltage clamp

PROJECT SUMMARY Recently-described SCN3A-related neurodevelopmental disorder (SCN3A-NDD) is caused by pathogenic variants in the gene SCN3A, which encodes the sodium (Na+) channel subunit Nav1.3. SCN3A-NDD is a devastating condition defined by treatment-resistant epilepsy and severe/profound intellectual disability (ID); surprisingly, many patients also exhibit malformation of cortical development (MCD), a developmental disturbance in the structural formation of the cerebral cortex of the brain, suggesting functional roles for Nav1.3 during embryological development. How genetic variants in SCN3A leads to epilepsy and neurodevelopmental disability, and how SCN3A variants lead to MCD, is unknown. Research is required to clarify the functional role of Nav1.3 during early brain development and to progress towards novel therapies or preventative measures for SCN3A-NDD, which is currently and untreatable disorder. This 5-year collaborative application employs novel tools and innovative neuroscience approaches to test the hypothesis that pathogenic variants in SCN3A lead to a disorder that includes epilepsy and MCD via dysregulated Na+ currents in migrating neurons of the developing cerebral cortex. Electrophysiological recordings in heterologous cell systems indicate that pathogenic SCN3A variants found in patients with SCN3A-NDD largely produce Na+ channels that exhibit gain of function due to increased persistent current and alterations in the voltage dependence of channel activation, which increase channel activity. However, the mechanistic basis of observed variability in epilepsy severity and presence or absence of MCD, is unclear. And how altered channel activity impacts the function of neurons has not been investigated. Proposed experiments will determine the relationship between specific SCN3A variants and correlated clinical phenotype (epilepsy, MCD, severity of ID) in a large cohort of human patients with SCN3A-NDD. To link SCN3A variants to dysfunction of ion channels and neurons, we will compare the biophysical properties of normal Na+ channels to channels containing variant Nav1.3; test cell-intrinsic effects of SCN3A variants in neurons generated from induced pluripotent stem cells from human SCN3A-NDD patients; and test effects of variant overexpression via in utero electroporation of mouse embryo followed by electrical recording in brain slices (Aim 1). The impact of variant SCN3A on the morphology of immature neurons and cytoarchitecture of the developing cerebral cortex will inform the role of SCN3A in development (Aim 2). To translate these findings towards clinical applications, we will attempt to ameliorate features of SCN3A-NND in advanced model systems, including a newly generated conditional point mutant mouse, via targeted manipulation of pathogenic Nav1.3-mediated Na+ current (Aim 3). Results will provide novel information on the role of Nav1.3 during brain development, and will define the pathogenic mechanisms of SCN3A-NDD towards development of novel, targeted therapies in human patients.

项目摘要 最近描述的SCN 3A相关神经发育障碍（SCN 3A-NDD）是由致病性 SCN 3A基因的变体，其编码钠（Na+）通道亚基Nav1.3。SCN 3A-NDD是一种 破坏性疾病，定义为难治性癫痫和重度/极重度智力残疾（ID）; 令人惊讶的是，许多患者还表现出皮质发育畸形（MCD）， 大脑皮层结构形成的障碍，表明Nav1.3的功能作用 在胚胎发育过程中。SCN 3A的遗传变异如何导致癫痫和神经发育 残疾，以及SCN 3A变体如何导致MCD尚不清楚。需要进行研究，以澄清职能作用 Nav1.3在早期大脑发育过程中的作用，并朝着新的治疗或预防措施的方向发展 SCN 3A-NDD，这是目前无法治疗的疾病。 这个为期5年的合作应用程序采用新颖的工具和创新的神经科学方法来测试 假设SCN 3A中的致病性变体通过以下途径导致包括癫痫和MCD在内的疾病： 发育中的大脑皮层迁移神经元的Na+电流失调。 异源细胞系统中的电生理记录表明， 患有SCN 3A-NDD的患者大量产生Na+通道，其由于增加的 持续电流和通道激活的电压依赖性的改变，这增加了通道 活动然而，观察到的癫痫严重程度和存在或不存在的变异性的机制基础， MCD，不清楚。通道活动的改变如何影响神经元的功能还没有研究。 拟议的实验将确定特定SCN 3A变体与相关临床表现之间的关系。 表型（癫痫，MCD，ID的严重程度）在患有SCN 3A-NDD的人类患者的大队列中的研究。链接 SCN 3A变体与离子通道和神经元功能障碍的关系，我们将比较SCN 3A变体的生物物理特性。 正常Na+通道转换为含有变体Nav1.3的通道;测试SCN 3A变体在正常Na+通道中的细胞内在效应。 由来自人SCN 3A-NDD患者的诱导多能干细胞产生的神经元;以及 通过小鼠胚胎的子宫内电穿孔随后在脑中电记录的变体过表达 切片（目标1）。SCN 3A变异体对未成熟神经元形态学和细胞构筑的影响 发育中的大脑皮层将告知SCN 3A在发育中的作用（目的2）。翻译这些 我们将尝试在晚期模型中改善SCN 3A-NND的特征， 系统，包括一个新产生的条件点突变小鼠，通过有针对性地操纵致病性 Nav1.3介导的Na+电流（目的3）。 研究结果将为Nav1.3在大脑发育过程中的作用提供新的信息，并将定义Nav1.3在大脑发育过程中的作用。 SCN 3A-NDD的致病机制，以开发人类患者的新型靶向治疗。