Pathomechanisms of SCN3A-related neurodevelopmental disorder

SCN3A相关神经发育障碍的发病机制

基本信息

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
项目类别：
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

项目摘要

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.

项目概要最近描述的 SCN3A 相关神经发育障碍 (SCN3A-NDD) 是由致病菌引起的基因 SCN3A 中的变体，该基因编码钠 (Na+) 通道亚基 Nav1.3。 SCN3A-NDD 是难治性癫痫和严重/极重度智力障碍（ID）所定义的破坏性病症；令人惊讶的是，许多患者还表现出皮质发育畸形（MCD），这是一种发育障碍。大脑皮层结构形成紊乱，提示 Nav1.3 的功能作用在胚胎发育过程中。 SCN3A 的遗传变异如何导致癫痫和神经发育障碍残疾以及 SCN3A 变异如何导致 MCD 尚不清楚。需要研究来阐明功能作用 Nav1.3 在早期大脑发育过程中的作用以及新疗法或预防措施的进展 SCN3A-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 SCN3A 的致病性变异可导致包括癫痫和 MCD 在内的疾病发育中的大脑皮层迁移神经元中 Na+ 电流失调。异源细胞系统中的电生理记录表明，致病性 SCN3A 变异存在于 SCN3A-NDD 患者主要产生 Na+ 通道，由于增加的 Na+ 通道而表现出功能获得通道激活的持续电流和电压依赖性的变化，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尚未得到研究。拟议的实验将确定特定 SCN3A 变异与相关临床之间的关系一大群 SCN3A-NDD 人类患者的表型（癫痫、MCD、ID 严重程度）。链接 SCN3A 变异导致离子通道和神经元功能障碍，我们将比较其生物物理特性正常 Na+ 通道到包含变体 Nav1.3 的通道；测试 SCN3A 变体的细胞内在效应由人类 SCN3A-NDD 患者的诱导多能干细胞产生的神经元；以及测试效果通过小鼠胚胎的子宫内电穿孔随后在大脑中进行电记录来过度表达变体切片（目标 1）。变异SCN3A对未成熟神经元形态和细胞结构的影响发育中的大脑皮层将告知 SCN3A 在发育中的作用（目标 2）。来翻译这些研究结果面向临床应用，我们将尝试改善高级模型中 SCN3A-NND 的特征系统，包括新生成的条件点突变小鼠，通过对致病性进行靶向操作 Nav1.3 介导的 Na+ 电流（目标 3）。结果将提供关于 Nav1.3 在大脑发育过程中的作用的新信息，并将定义 SCN3A-NDD 的致病机制有助于开发人类患者的新型靶向疗法。