Cellular and circuit function of Ndnf-expressing interneurons in a mouse model of a neurodevelopmental disorder

项目总结/摘要 每年，六分之一的儿童被诊断患有神经发育障碍，如自闭症谱系障碍， 智力残疾或癫痫。这种疾病严重影响了情感，社会，身体和经济 患者及其护理人员的健康，以及对这些疾病的潜在病理生理学的了解不足 这些疾病减缓了有效疗法的发现。然而，有证据表明， 作为一类疾病与GABA能抑制性中间神经元的选择性功能障碍有关， 大脑皮层 Dravet综合征，由编码Nav1.1电压门控钠离子通道的SCN 1A基因的致病性变体引起 通道A亚基，是由中间神经元功能障碍引起的神经发育障碍的典型实例， 因为新皮层中的中间神经元优先依赖Nav1.1产生和传播动作电位。 重要的是，大脑皮层中间神经元是一个功能异质的群体;因此，理解 不同类别的中间神经元对正常大脑中微电路功能的贡献，以及 病理学背景对于进一步阐明神经发育障碍的机制至关重要。 在这个建议中，我将确定最少研究的主要人群的新皮层的功能或功能障碍， 中间神经元，表达神经源性神经营养因子（NDNF），位于大脑皮层微回路内 Dravet综合征这些细胞在新皮层的第一层富集，在那里它们被认为在以下方面发挥作用： 感觉处理和调节皮层中的抑制性音调。使用临床相关且特征良好的 Dravet综合征小鼠模型，我将首先建立电生理，突触和形态学 Scn 1a +/-小鼠中表达NdNF的中间神经元相对于野生型小鼠的体外特性（目的1）。然后我将 确定这些细胞在Scn 1a +/-小鼠中相对于野生型小鼠的皮质微回路中的行为 使用多光子成像和光遗传学方法（Aim 2）。这项提案不仅将提供新的数据， 在健康和疾病中，对一种未充分研究的中间神经元亚型进行研究，但也提供了一套训练， 先进的电生理和光学技术，将有助于培养申请人对未来的职业生涯 作为一名研究神经系统疾病中电路功能障碍和新疗法开发的医生科学家， 和治愈方法

PROJECT SUMMARY/ABSTRACT Each year, 1 in 6 children are diagnosed with a neurodevelopmental disorder such as autism spectrum disorder, intellectual disability, or epilepsy. Such disorders severely impact the emotional, social, physical, and economic wellbeing of patients and their caregivers, and a poor understanding of the underlying pathophysiology of these disorders has slowed the discovery of effective therapies. There is evidence, however, that neurodevelopmental disorders as a class are associated with selective dysfunction of GABAergic inhibitory interneurons in the cerebral cortex. Dravet Syndrome, caused by pathogenic variants in the SCN1A gene encoding the Nav1.1 voltage-gated sodium channel a subunit, is a canonical example of a neurodevelopmental disorder caused by interneuron dysfunction, as interneurons in the neocortex preferentially rely on Nav1.1 for action potential generation and propagation. Importantly, cerebral cortical interneurons are a functionally heterogenous population; therefore, understanding the contribution of different classes of interneurons to microcircuit function in normal brain, and dysfunction in the setting of pathology, is essential for further elucidating the mechanisms of neurodevelopmental disorders. In this proposal, I will determine the function or dysfunction of the least studied major population of neocortical interneurons, those expressing Neuron-Derived Neurotrophic Factor (Ndnf), within cerebral cortical microcircuits in Dravet Syndrome. These cells are enriched in layer 1 of neocortex, where they are thought to play a role in sensory processing and regulating inhibitory tone in the cortex. Using a clinically-relevant and well-characterized mouse model of Dravet Syndrome, I will first establish the electrophysiologic, synaptic, and morphologic properties of Ndnf-expressing interneurons in Scn1a+/- mice relative to wild-type mice in vitro (Aim 1). I will then determine the behavior of these cells within cortical microcircuits in Scn1a+/- mice relative to wild-type in vivo using multiphoton imaging and optogenetic approaches (Aim 2). This proposal will not only provide novel data on an understudied interneuron subtype, both in health and disease, but also provide training in a suite of advanced electrophysiologic and optical techniques that will serve to train the applicant towards a future career as a physician-scientist studying circuit dysfunction in neurological disorders and development of new therapies and cures.