Voltage-gated sodium channel regulation of neocortical development

电压门控钠通道(VGSCs)是神经元兴奋性的重要调节因子，与严重的神经系统和神经精神障碍有关，包括自闭症、认知和运动障碍以及癫痫。包括SCN8A在内的VGSCs突变是儿童难治性癫痫最常见的遗传原因之一。尽管最近取得了进展，但癫痫仍然是一个需要改进治疗的长期问题，因为大约40%的癫痫患者无法通过目前的治疗干预实现足够的癫痫发作控制。申请者梅金森博士在癫痫研究方面有很强的背景。他在安德鲁·埃斯凯格博士的指导下在埃默里大学完成了博士学位，在那里他对携带临床相关突变的小鼠进行了详细的遗传、分子和行为分析，包括对VGSCs Scn1a和Scn8a的多项研究。在他博士后培训的第一部分，Makinson博士与John Huguenard博士(斯坦福大学)合作，确定了一种新的失神发作产生机制，涉及Scn8a的减少和丘脑反复抑制的同时损害。他还在与Sergiu Pasca博士(斯坦福大学)的实验室合作中发挥了重要作用，在该实验室中，他表征了从人类诱导多能干细胞(HiPSCs)成长为3D皮质样结构的神经元的电生理特性。最近，马金森博士展示了特定区域的球体，包括兴奋性(Pallial)型和GABA能(大脑皮层下)型，可以组装成功能完整的神经网络。在这项建议中，Makinson博士试图建立SCN8A损伤的啮齿动物和体外人类模型，并使用这些模型来询问与临床相关的突变的潜在致病机制，并确定治疗疾病的新治疗策略。这些研究旨在为最终导致严重癫痫脑病和认知障碍的疾病进展的最早点提供机械性的洞察。具体地说，Makinson博士试图研究在携带SCN8A突变的脑球体内发生的神经元兴奋性、网络活动和神经元迁移的变化。Makinson博士将由Huguenard博士(主要导师)和Pasca博士(共同导师)以及包括Christopher Lee-Messer博士、Kimford Meader博士、Justin Du Bois博士和Liqun Luo博士在内的顾问委员会监督。马金森博士将接受神经发育方面的高级指导，并接受帕斯卡博士在产生携带SCN8A基因突变的3D hiPSC衍生神经元培养方面的专家培训。Huguenard博士将提供电生理学、光遗传学、多光子成像、计算机编程以及复杂生物数据分析方面的高级培训。Makinson博士的长期目标是成为一名独立的终身教职研究员，研究癫痫的神经元和分子机制。

Voltage-gated sodium channels (VGSCs) are critical regulators of neuronal excitability and are associated with severe neurologic and neuropsychiatric disorders including autism, cognitive and motor impairment, and epilepsy. Mutations in VGSCs, including SCN8A, are among the most common genetic causes of treatment- resistant epilepsy in children. Despite recent advances, epilepsy has remained a persistent problem that needs improved treatments, as approximately 40% of epileptic patients do not achieve sufficient seizure control with current therapeutic interventions. The applicant, Dr. Makinson, has a strong background in epilepsy research. He completed his PhD at Emory University under the mentorship of Dr. Andrew Escayg, where he performed detailed genetic, molecular, and behavioral analyses of mice carrying clinically-relevant mutations, including multiple studies on the VGSCs Scn1a and Scn8a. For the first part of his postdoctoral training Dr. Makinson worked with Dr. John Huguenard (Stanford University) to identify a novel mechanism for absence seizure generation involving reductions in Scn8a and concurrent impairment in recurrent inhibition in the thalamus. He also was instrumental in a collaboration with the laboratory of Dr. Sergiu Pasca (Stanford University) in which he characterized the electrophysiological properties of neurons derived from human induced pluripotent stem cells (hiPSCs) grown into a 3D cortex-like structure. Recently, Dr. Makinson showed that region-specific spheroids, including excitatory (pallial) and GABAergic (subpallial) types, can be assembled to produce functionally integrated neural networks. In this proposal, Dr. Makinson seeks to develop rodent and in vitro human models of SCN8A impairment and to use these models to interrogate the underlying pathogenic mechanisms of clinically-relevant mutations and to identify new therapeutic strategies to treat disease. These studies are designed to provide mechanistic insight into the earliest points of disease progression that ultimately lead to severe epileptic encephalopathies and cognitive impairment. Specifically, Dr. Makinson seeks to investigate the changes in neuronal excitability, network activity, and neuronal migration that occur in cerebral spheroids carrying mutations in SCN8A. Dr. Makinson will be supervised by Drs. Huguenard (primary mentor) and Pasca (co-mentor) as well as the advisory committee including Drs. Christopher Lee-Messer, Kimford Meador, Justin Du Bois, and Liqun Luo. Dr. Makinson will receive advanced instruction in neurodevelopment and expert training in the generation of 3D hiPSC-derived neuronal cultures carrying mutations in the SCN8A gene by Dr. Pasca. Dr. Huguenard will provide advanced training in electrophysiology, optogenetics, multiphoton imaging, computer programming, and in the analysis of complex biological data. Dr. Makinson, has the long-term goal of becoming an independent tenure-track investigator studying the neuronal and molecular mechanisms of epilepsy.