Dissecting Cell Type Specific Functions of CHD7 in Development of the Neocortex

项目摘要/摘要 这项建议的目的是确定染色质重构体CHD7的杂合突变是如何 (嗜铬区解旋酶DNA结合蛋白7)干扰新皮质的发育，导致 与充电综合征相关的神经发育异常。冲锋综合征的特点是 严重的行为和认知问题，包括执行功能障碍和自闭症谱系障碍 (ASD)。拟议的研究小组最近发现了CHD7杂合子新皮质的异常 小鼠，这意味着CHD7在关键的，时间上不同的发育过程中。初步数据显示， 在这些小鼠中，新皮质的前后部(A-P)模式被破坏，CHD7直接调节 A-P图案的主调控子Nr2f1(COUP-TF1)的表达。这些小鼠也表现出皮质 发育不全，表明CHD7与皮质生长有关。此外，兴奋性和抑制性突触也存在于深层 CHD7单倍体功能不全影响前额叶皮质(PFC)的主神经元。两人都是高管 功能障碍和ASD与PFC功能障碍有关。因此，这些发现提供了人们期待已久的 有机会确定CHD7单倍体不足扰乱新皮质发育的机制。 CHD7的功能依赖于上下文；因此，一个重要的焦点将是定义特定于性别、区域和细胞类型的 功能和机制。该项目的具体目标是：1)检验CHD7单倍体不足的假设 破坏新皮质的A-P模式，2)确定CHD7在神经中的分子和细胞功能 新皮质和大脑皮层下的干/祖细胞和3)检验CHD7具有细胞类型特异性的假设 在前额叶突触发育中的作用。该团队将使用标准和创新的方法来 可视化和量化A-P图案化标记的表达模式和水平，并对区域、细胞- 兴奋性和抑制性神经发生的性别特异性异常。下一代散装和单电池 测序方法将被用来识别不同区域和 CHD7缺乏的男女发育中的新皮质的细胞类型。多个研究所的团队汇聚在一起 在CHD蛋白的神经发育功能方面的专业知识(巴森)，翻译和模型研究 Charge综合征(Martin)、皮质发育基因组学(Kwan)和突触生理学(Andreae)。 总而言之，这项工作将全面了解CHD7单倍体不足对 新皮质发育中的多个过程及CHD7在神经细胞中的细胞类型特异性功能 祖细胞分化和PFC电路组装。这项工作的成功完成将产生 识别神经发育机制和基础回路所需的知识和工具 与充电综合征和其他相关障碍相关的特定行为和认知表型。

PROJECT SUMMARY/ABSTRACT The aim of this proposal is to determine how heterozygous mutation of the chromatin remodeler CHD7 (Chromodomain Helicase DNA-binding protein 7) disrupts development of the neocortex, leading to the neurodevelopmental anomalies associated with CHARGE syndrome. CHARGE syndrome is characterized by substantial behavioral and cognitive problems, including executive dysfunction and Autism Spectrum Disorder (ASD). The proposed research team recently identified abnormalities in the neocortex of Chd7 heterozygous mice, implicating CHD7 in key, temporally distinct developmental processes. Preliminary data suggest that anterior-posterior (A-P) patterning of the neocortex is disrupted in these mice and that CHD7 directly regulates the expression of a master regulator of A-P patterning, Nr2f1 (COUP-TF1). These mice also exhibit cortical hypoplasia, implicating Chd7 in cortical growth. Furthermore, excitatory and inhibitory synapses onto deep layer principal neurons of the prefrontal cortex (PFC) are affected by Chd7 haploinsufficiency. Both executive dysfunction and ASD have been linked to PFC dysfunction. Thus, these findings provide the long-sought opportunity to identify the mechanisms whereby CHD7 haploinsufficiency disrupts neocortical development. Chd7 function is context-dependent; hence, a significant focus will be to define sex-, region- and cell-type-specific functions and mechanisms. This project's specific aims are to 1) test the hypothesis that Chd7 haploinsufficiency disrupts A-P patterning of the neocortex, 2) define the molecular and cellular functions of Chd7 in neural stem/progenitor cells of the neocortex and subpallium and 3) test the hypothesis that Chd7 has cell-type-specific functions in the development of synapses in the PFC. The team will use standard and innovative methods to visualize and quantify the expression patterns and levels of markers of A-P patterning, and quantify region-, cell- and sex-specific abnormalities in excitatory and inhibitory neurogenesis. Bulk and single cell next generation sequencing approaches will be used to identify transcriptional and chromatin changes in different regions and cell types of the Chd7-deficient developing neocortex in both sexes. The multi-institute team brings together expertise in neurodevelopmental functions of CHD proteins (Basson), translational and modeling studies of CHARGE syndrome (Martin), genomics of cortical development (Kwan), and synapse physiology (Andreae). Together, this work will provide a comprehensive understanding of the impacts of CHD7 haploinsufficiency on multiple processes in development of the neocortex and identify cell-type-specific functions for CHD7 in neural progenitor differentiation and PFC circuit assembly. Successful completion of this work will generate the knowledge and tools necessary to identify the neurodevelopmental mechanisms and circuits that underlie specific behavioral and cognitive phenotypes associated with CHARGE syndrome and other related disorders.