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

项目摘要/摘要 每年，每6名儿童中就有1名被诊断出患有神经发育障碍，如自闭症谱系障碍， 智力障碍，或癫痫。这种障碍严重影响了情感、社会、身体和经济 患者及其照顾者的健康状况，以及对这些疾病的潜在病理生理学缺乏了解 精神障碍延缓了有效疗法的发现。然而，有证据表明，神经发育 GABA能抑制中间神经元的选择性功能障碍是一类疾病 大脑皮层。 由编码Nav1.1电压门控钠的SCN1A基因的致病变异引起的Drave氏综合征 通道是一个亚单位，是由神经元间功能障碍引起的神经发育障碍的典型例子， 因为新大脑皮层的中间神经元优先依赖Nav1.1来产生和传播动作电位。 重要的是，大脑皮质间神经元是一个功能不同的群体；因此，理解 不同类型中间神经元对正常脑微电路功能的影响及脑功能障碍 病理学的设置，对于进一步阐明神经发育障碍的机制是必不可少的。 在这项提案中，我将确定研究最少的新皮质主要人群的功能或功能障碍 大脑皮层微循环中表达神经元衍生神经营养因子(NDNF)的中间神经元 在德拉维氏综合症中。这些细胞富含在新皮质的第一层，在那里它们被认为在 大脑皮层的感觉处理和调节抑制音。使用与临床相关且特征良好的 建立Dravet综合征小鼠模型，首先建立电生理、突触和形态 Scn1a+/-小鼠相对于野生型小鼠表达Ndnf的中间神经元的体外特性(目标1)。那我会的 确定Scn1a+/-小鼠大脑皮质微循环中这些细胞相对于野生型的在体行为 使用多光子成像和光遗传方法(目标2)。这项提议不仅将提供新的数据 在健康和疾病方面都是研究不足的中间神经元亚型，但也提供了一套 先进的电生理学和光学技术，将为申请人未来的职业生涯提供培训 作为一名内科科学家，研究神经疾病中的回路功能障碍和新疗法的开发 还有治愈方法。

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.