Transcriptional regulation over neurogenesis of cortical output neuron segmental identity and diversity

皮质输出神经元节段同一性和多样性的神经发生的转录调控

基本信息

批准号：
10638147
负责人：
Vibhu Vinodchandra Sahni
金额：
$ 46.38万
依托单位：
WINIFRED MASTERSON BURKE MED RES INST
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-03-01 至 2028-02-29
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10638147
关键词：
AT Rich Sequence ATAC-seq Adult Affect Age Amyotrophic Lateral Sclerosis Axon Binding Proteins Birth Brain Stem Cells Cerebral Palsy Corticospinal Tracts Data Development Disease model Embryo Embryonic Development Foundations Gene Delivery Genes Genetic Transcription Goals Health Care Costs Human In Vitro Individual Injections Injury Investigation Knock-in Knock-in Mouse Knockout Mice Label Life Link Mediating Molecular Molecular Target Motor Neuron Disease Motor Neurons Motor output Movement Mus Natural regeneration Neocortex Nervous System Neurons Output Paralysed Pathway interactions Play Population Process Public Health Quality of life Recovery Recovery of Function Regulation Reporter Research Resolution Role Specific qualifier value Specificity Spinal Spinal Cord Spinal cord injury Stroke Testing Time Transcriptional Regulation Transgenic Organisms Traumatic Brain Injury Vertebral column Work conditional knockout cost directed differentiation experimental study functional plasticity gain of function high-throughput drug screening in utero in vivo loss of function loved ones motor control motor impairment motor recovery neocortical neurogenesis neuropeptide Y novel overexpression personalized approach post stroke postmitotic postnatal regenerative repaired single-cell RNA sequencing skills spasticity stem cell differentiation stroke recovery transcription factor transcriptomics translational neuroscience

项目摘要

Subcerebral projection neurons (SCPN) reside in the neocortex, and extend axons to subcerebral targets in the brainstem and spinal cord. Corticospinal neurons (CSN), a subclass of SCPN, project to the spinal cord and their axons form the corticospinal tract (CST), a critical circuit for voluntary motor control. In addition, projections from the neocortex to brainstem targets function in parallel with CSN to exert motor control. Degeneration of these projection neurons in amyotrophic lateral sclerosis (ALS), along with degeneration of spinal motor neurons, causes spasticity and paralysis. In humans, damage to the CST after spinal cord injury is a principal cause of loss of voluntary motor control. Further, integrity of corticospinal connectivity is centrally linked to recovery from stroke and cerebral palsy. There have been multiple investigations detailing the role of cortico-brainstem vs. corticospinal projections in both motor control, as well as their distinct contributions to functional recovery in these distinct causes of paralysis. However, it remains unclear when and how these distinct projections are established during development. Understanding the molecular basis of this specification and differentiation during development therefore holds significant promise in establishing approaches that are tailored to enhancing plasticity of these related, yet distinct circuits. A necessary first step toward this ultimate goal is to identify the molecular mechanisms directing SCPN axons to brainstem (cortico-brainstem neurons) versus spinal cord (CSN). Ongoing work in our lab has identified that such projections are initially specified during the process of axon extension during development. We have identified that cortico-brainstem and corticospinal neurons express distinct genes and can be molecularly distinguished in mice by birth. Further our data suggest that the transcriptional regulator Satb2 acts, in part, to specify cortico-brainstem neurons. This proposal investigates the hypothesis that transcriptional regulation controls the development of cortico-brainstem vs. corticospinal projections by late embryonic development in mice. Building on this foundation, we will first identify the time point in development when these projections are specified using knock-in Cre reporter mice (Aim 1). This will be tested using intracerebral injections of AAV-reporters at distinct developmental times in utero with adult analysis of axonal projections. In Aim 2, we will investigate the transcriptional targets of Satb2 in SCPN at later developmental times by profiling all SCPN in Satb2 WT and conditional KO mice, as well as by Satb2 overexpression, at single cell resolution. Finally, in Aim 3 using subpopulation-specific transgenic Cre lines, we will investigate SCPN axon targeting in both Satb2 loss- and gain-of-function. In addition, we will investigate whether misexpression of Satb2 target genes can alter SCPN targeting to the brainstem vs. spinal targets. Together, our work will discern in-depth, the mechanisms of when and how transcriptional regulation controls SCPN segmental “identity” thereby providing a mechanistic framework for subsequent identification of molecules controlling segmentally appropriate SCPN connectivity with subcerebral targets.

脑脑投射神经元（SCPN）位于新皮层中，并将轴突扩展到脑脑中脑靶标脑干和脊髓。皮质脊髓神经元（CSN），SCPN的子类，向脊髓及其投影轴突形成皮层脊髓道（CST），这是一种自愿运动控制的关键电路。此外，来自脑干目标的新皮层与CSN并行发挥运动控制。这些变性肌萎缩性侧性硬化症（ALS）的投射神经元以及脊柱运动神经元的变性引起痉挛和麻痹。在人类中，脊髓损伤后对CST的损害是自愿控制的损失。此外，皮质脊髓连通性的完整性与从中风和脑瘫。已经进行了多次调查，详细介绍了Cortico-Brainstem VS的作用。运动控制中的皮质脊髓项目及其对功能恢复的独特贡献这些瘫痪的独特原因。但是，尚不清楚这些不同的项目何时以及如何在开发过程中建立。了解该规范和分化的分子基础因此，在开发过程中，在建立量身定制的方法方面具有巨大的希望这些相关但独特的电路的可塑性。朝着这个最终目标迈出的必要第一步是确定将SCPN轴突引导到脑干（皮质脑神经元）与脊髓的分子机制（CSN）。我们实验室中正在进行的工作已经确定，此类项目最初是在此过程中指定的发育过程中的轴突延伸。我们已经确定皮质脑和皮质脊髓神经元表达不同的基因可以通过出生在小鼠中分子区分。此外，我们的数据表明转录调节剂SATB2在某种程度上起作用，以指定皮质脑神经元。该提案调查了转录调节控制皮质脑系统与皮质脊髓的发展的假设小鼠晚期胚胎发育的预测。在这个基础的基础上，我们将首先确定时间点在使用敲入CRE报告的小鼠指定这些项目时（AIM 1）。这将进行测试在子宫内使用脑内注射AAV-Reporters的成人分析轴突项目。在AIM 2中，我们将在稍后研究SCPN中SATB2的转录目标通过分析SATB2 WT和有条件的KO小鼠的所有SCPN以及SATB2的发育时间过表达，在单细胞分辨率下。最后，在AIM 3中使用亚群特异性转基因CRE系，我们将研究SATB2损失和功能获得的SCPN轴突靶向。此外，我们将调查 SATB2靶基因的表现是否可以改变SCPN靶向脑干与脊柱靶标。我们的工作将共同辨别到何时以及如何控制转录调节的机制 SCPN节段“身份”，从而提供了一个机械框架，以随后识别分子通过亚脑靶标控制分段适当的SCPN连接性。