Neuronal and Behavioral Deficits Associated with Scn2a Deficiency in Autism Spectrum Disorder

项目摘要/摘要 自闭症谱系障碍(Asd)是一种与社交功能受损有关的神经发育障碍。 沟通和行为异常，影响到美国54名儿童中的1名(CDC.gov)。 编码神经元电压门控钠通道Nav1.2的SCN2A已被确定为领先的 与ASD相关的基因。我们已经鉴定了一种新的SCN2A缺陷小鼠模型，该模型是通过 靶向基因陷阱敲除(GtKO)策略，并具有内置的遗传救援元件。我们的预赛 数据显示纯合子Scn2agtKO/gtKO小鼠有严重的行为异常，包括焦虑样 行为、筑巢障碍和社会缺陷。我们还发现兴奋-抑制(E/I)平衡升高。 MPFC的锥体神经元，它与自闭症和社会缺陷有关。然而，存在着一个关键差距。 关于mPFC内神经元放电如何受到E/I平衡升高的影响，以及在多大程度上 操纵E/I平衡将改变Scn2agtKO/gtKO小鼠的行为结局。为了解决这一差距，我们 建议测试SCN2A缺乏增加E/I平衡，损害神经元的一个重要假说 MPFC的反应，并导致社会缺陷，可以通过有针对性的遗传和药物来挽救 干预措施。在目标1，我们将评估突触特性和mPFC神经元的活体放电使用脑- 脑片膜片钳记录和活体神经像素记录。我们的发现有望在细胞水平上提供 SCN2A缺乏症的局部网络水平神经病理机制。在目标2中，我们将确定神经元 利用光遗传学操作mPFC微电路中的E/I平衡时的触发和行为结果 和化学遗传学。我们的发现将支持E/I平衡调制对纠正高血压的意义。 行为缺陷。在目标3中，我们将评估定时遗传和药物救援的疗效 确定干预的最佳窗口。我们的研究在以下方面具有重要意义：i)SCN2A缺乏症 有待研究的是ASD的主要单基因形式之一；II)mPFC的兴奋和抑制(E/I)平衡 被彻底解剖的微电路与社会缺陷密切相关；以及iii)基因拯救和 将被测试的药物干预具有明显的临床相关性，并将为 介绍SCN2A缺乏症相关疾病的治疗进展。我们的研究有 以下创新：i)使用表现出严重细胞和行为缺陷的新型Scn2agtKO/gtKO小鼠；ii) 实现遗传和药物挽救的创新方法；以及三)使用尖端技术 包括高密度神经像素的活体记录。申请人为早期调查员(ESI)，其 团队在钠通道电生理学、动物行为、遗传学和 药理学。该小组非常适合在项目内全面完成拟议的工作 时间框架，并产生有影响力的成果，以推动这一领域的发展。

Project Summary/Abstract Autism spectrum disorder (ASD) is a neurodevelopmental disorder associated with impaired social communications and behavioral abnormalities, which affects ~1 in 54 children in the United States (CDC.gov). SCN2A, encoding neuronal voltage-gated sodium channel Nav1.2, has been identified as one of the leading genes associated with ASD. We have characterized a novel Scn2a-deficient mouse model that is generated via targeted gene-trap knockout (gtKO) strategy and possesses a built-in genetic rescue element. Our preliminary data revealed profound behavioral abnormalities in homozygous Scn2agtKO/gtKO mice including anxiety-like behaviors, impaired nesting and social deficits. We also identified elevated excitation-inhibition (E/I) balance in pyramidal neurons of mPFC, which has been implicated in ASD and social deficits. However, a critical gap exists regarding how in vivo neuronal firings in mPFC are affected by elevated E/I balance and to what extent the manipulation of E/I balance will alter the behavioral outcomes in Scn2agtKO/gtKO mice. To address this gap, we propose to test an overarching hypothesis that Scn2a deficiency increases E/I balance, impairs neuronal responses in mPFC, and results in social deficits that can be rescued with targeted genetic and pharmacological interventions. In Aim 1, we will assess the synaptic properties and in vivo firing of neurons in mPFC using brain- slice patch-clamp recording and Neuropixels in vivo recording. Our findings are expected to provide cellular-level and local network level neuropathological mechanisms of Scn2a deficiency. In Aim 2, we will determine neuronal firings and behavioral outcomes in response to manipulating E/I balance in mPFC microcircuit using optogenetics and chemogenetics. Our findings will bolster the significance of E/I balance modulation for correction of behavioral deficits. In Aim 3, we will evaluate the efficacy of timed genetic and pharmacological rescue to determine optimal windows for intervention. Our study is significant in the following ways: i) SCN2A deficiency to be studied is among the leading monogenetic forms of ASD; ii) Excitation and inhibition (E/I) balance of mPFC microcircuit to be thoroughly dissected is closely associated with social deficits; and iii) Genetic rescue and pharmacological intervention to be tested are of clear clinical relevance, and will provide translational basis to inform therapeutic development for the treatment of Scn2a-deficiency related disorders. Our study has the following innovations: i) use of novel Scn2agtKO/gtKO mice that display profound cellular and behavioral deficits; ii) innovative ways to achieve genetic and pharmacological rescue; and iii) use of cutting-edge technologies including high density Neuropixels in vivo recordings. The applicant is an early stage investigator (ESI), whose team has extensive expertise in sodium channel electrophysiology, animal behaviors, genetics and pharmacology. The team is well suited to carry out the proposed work to its full completion within the project timeframe, and generate impactful outcomes to advance the field.