Molecular Development and Diversity of Callosal Projection Neurons

胼胝体投射神经元的分子发育和多样性

• 批准号: 10117292
• 负责人: JEFFREY D MACKLIS
• 金额: $ 39.2万
• 依托单位: HARVARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-15 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10117292
• 关键词: Area; Axon; Behavior; Behavior Disorders; Behavioral; Brain; Cells; Cerebral cortex; Cerebral hemisphere; Cognition; Cognitive; Complex; Corpus Callosum; Development; Developmental Biology; Diagnosis; Disease; Electroporation; Evolution; Exhibits; Functional disorder; Future; Gene Expression; Gene Expression Regulation; Generations; Genes; Genetic Transcription; Goals; Growth Cones; Human; Individual; Intellectual functioning disability; Interneurons; Investigation; Knowledge; Label; Link; Location; Mental disorders; Molecular; Mosaicism; Motor; Mus; Nature; Neurons; Parents; Phenotype; Plasmids; Play; Population; Population Analysis; Positioning Attribute; Prevention; Process; Proteins; Proteome; Proteomics; Publishing; RNA; Regulation; Research; Role; Schizophrenia; Sensory; Somatosensory Cortex; Specific qualifier value; Structure; System; Technology; Therapeutic; Time; Transcriptional Regulation; Visualization; Work; autism spectrum disorder; axon growth; base; behavior test; behavioral phenotyping; combinatorial; developmental disease; gain of function; genetic analysis; genetic manipulation; hippocampal pyramidal neuron; human disease; in utero; innovation; insight; interest; neocortical; neuron development; neuronal cell body; novel; novel strategies; prevent; progenitor; programs; recombinase; somatosensory; tool; transcriptomics

The long-term goals of the proposed research are both to elucidate central molecular controls over development and diversity of neocortical callosal projection neuron (CPN) connectivity, and to identify potential causes and therapeutic approaches to disease involving CPN circuitry. CPN are the broad population of inter-hemispheric pyramidal neurons whose axons connect the two cerebral hemispheres via the corpus callosum. CPN play key roles in high-level associative, integrative, cognitive, behavioral, sensory, and motor functions, based on precise, area-specific CPN subtype connectivity and diversity. Disruptions in CPN development are correlated with deficits in multiple disorders, including agenesis of the corpus callosum, autism spectrum disorders, and schizophrenia. Currently, how the remarkable diversity of CPN subtypes and connectivity is specified, and how transcriptional programs implement specific connectivity via local, cell-autonomous effectors, is unknown. Our lab recently identified a combinatorially-expressed set of genes that both define CPN as a broad population, and identify novel subpopulations of CPN during development (Neuron, 2005, 2016a,b; J Neurosci, 2009; Cer Cor, 2016a,b). We also developed innovative approaches to investigate subtype-specific, subcellular growth cone (GC) molecular machinery. Building on this work, we propose deep and rigorous functional investigation of Cited2 control over precise CPN connectivity & circuit wiring, including RNAs & proteins detected uniquely in GCs. Cited2 is an exemplar transcriptional co-regulator that we hypothesize functions importantly in development of precise areally- and functionally-specific CPN circuitry in somatosensory cortex, and its dysfunction elucidates disorders of CPN connectivity and diversity. We have already identified that Cited2 regulates and refines two stages of precise CPN development and diversity, functioning 1) broadly in basal progenitors to regulate generation of superficial layer CPN, and 2) postmitotically in an area-restricted manner to refine distinct, precise identity and development of somatosensory (S1) CPN. To connect Cited2 transcriptional regulation to local implementation of S1 CPN connectivity in developing GCs, we propose to: Aim 1) investigate CPN-autonomy of Cited2 regulatory function in S1 CPN postmitotic development and connectivity, via novel mosaic, recombinase-based genetic manipulation technology (“BEAM”) for dual population analysis; Aim 2) investigate GC & soma RNA & proteomes of WT vs Cited2 cKO S1 CPN during axon development via new and innovative approaches, to gain direct mechanistic understanding of CPN circuit development at critical developmental stages; Aim 3) investigate the specific function of GC-localized downstream effectors that are dysregulated in Cited2-null CPN; and Aim 4) investigate the integrated function of precise CPN circuit development in cognitive & ASD-relevant behavior. Together, the proposed studies will provide substantial insight from gene to circuit to behavior into molecular control over development, diversity, and precision of connectivity of CPN subtypes with distinct function and integration of cortical information, processes centrally disrupted in human disorders. Controls over CPN connectivity are now essentially unknown, and transcriptional dysregulation has not been previously connected to downstream local effectors of circuit development. This research will contribute to understanding cortical organization, function, and potentially toward prevention, diagnosis, and therapy of human disorders.

这项拟议研究的长期目标既是阐明对发育的中央分子控制，也是为了 新皮质胼胝体投射神经元(CPN)连接的多样性，并找出潜在的原因和治疗 涉及CPN回路的疾病的治疗方法。CPN是大脑半球间锥体神经元的广泛群体 其轴突通过穹隆体连接到两个大脑半球。CPN在高水平的联想、整合、认知、行为、感觉和运动功能中发挥关键作用，其基础是精确的、特定区域的CPN亚型连通性和多样性。CPN发育中断与多种疾病的缺陷相关，包括胼胝体发育不全、自闭症谱系障碍和精神分裂症。目前，CPN亚型和连接性的显著多样性是如何确定的，以及转录程序如何通过局部的细胞自主效应器实现特定的连接性，尚不清楚。我们的实验室最近发现了一组组合表达的基因，这些基因既将CPN定义为一个广泛的种群，又在发育过程中识别了CPN的新亚群(Neuron，2005,2016a，b；J Neurosci，2009；Cer Cor，2016a，b)。我们还开发了创新的方法来研究亚型特定的亚细胞生长锥(GC)分子机制。在这项工作的基础上，我们建议对Cited2对CPN精确连接和电路布线的控制进行深入而严格的功能研究，包括在GC中唯一检测到的RNA和蛋白质。Cited2是一个典型的转录辅助调节因子，我们推测它在躯体感觉皮质中精确的区域和功能特异性CPN回路的发育中具有重要功能，它的功能障碍阐明了CPN连接和多样性的障碍。 我们已经确定，Cited2调节和完善了CPN精确发展和多样性的两个阶段， 功能1)广泛地在基础前体细胞中调节浅层CPN的产生，以及2)以区域受限的有丝分裂后方式完善体感(S1)CPN的独特、准确的识别和发育。为了将Cited2转录调控与Cited2 Cited2 CKO S1 CPN连接的局部实现联系起来，我们建议：目的1)通过用于双群体分析的新型嵌合、基于重组酶的遗传操作技术(“BEAM”)，研究Cited2在S1 CPN有丝分裂后发育和连接中的CPn自主性；目的2)通过新的和创新的方法研究WT和Cited2 CKO S1 CPN在轴突发育过程中的GC和Soma RNA和蛋白质组，以直接从机制上了解关键发育阶段Cited2环路的发育；目的3)研究Cited2-空CPN中GC定位的下游效应因子的特定功能；目的4)探讨精确的CPN回路发育在认知和ASD相关行为中的整合作用。总之，这些拟议的研究将为从基因到电路再到行为的分子控制CPN亚型的发育、多样性和连接的精确度提供实质性的见解，这些亚型具有不同的功能和皮质信息的整合，这些过程在人类疾病中集中中断。对CPN连接的控制现在基本上是未知的，转录失调以前没有与电路发育的下游局部效应器联系起来。这项研究将有助于了解大脑皮质的组织、功能，并有可能对人类疾病的预防、诊断和治疗做出贡献。