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.

大脑下投射神经元（SCPN）位于新皮质中，并将轴突延伸至大脑下目标脑干和脊髓神经元 (CSN) 是 SCPN 的一个亚类，投射到脊髓及其神经元。轴突形成皮质脊髓束（CST），这是自主运动控制的关键回路。新皮质到脑干的目标与 CSN 并行发挥运动控制的作用。肌萎缩侧索硬化症（ALS）中的投射神经元以及脊髓运动神经元的退化，在人类中，脊髓损伤后 CST 受损是导致痉挛和瘫痪的主要原因。此外，皮质脊髓连接的完整性与自主运动控制的丧失密切相关。已经有多项研究详细说明了皮质脑干与脑干的作用。运动控制中的皮质脊髓投射，以及它们对功能恢复的独特贡献然而，目前尚不清楚这些不同的预测何时以及如何发生。了解该规范和分化的分子基础。因此，在开发过程中，在建立专门的方法以增强这些相关但又不同的电路的可塑性，实现这一最终目标的第一步是确定这些电路的可塑性。将 SCPN 轴突引导至脑干（皮质脑干神经元）与脊髓的分子机制（CSN）我们实验室正在进行的工作已经确定，此类预测最初是在过程中指定的。我们已经确定皮质脑干和皮质脊髓神经元在发育过程中表达轴突延伸。我们的数据进一步表明，不同的基因可以在小鼠出生时进行分子区分。转录调节因子 Satb2 的部分作用是指定皮质脑干神经元。假设转录调控控制皮质脑干与皮质脊髓的发育在此基础上，我们将首先确定时间点。在开发中，当使用敲入 Cre 报告小鼠指定这些投影时（目标 1）。在子宫内不同发育时期使用 AAV 报告基因脑内注射，并进行成人分析在目标 2 中，我们稍后将研究 SCPN 中 Satb2 的转录靶标。通过分析 Satb2 WT 和条件 KO 小鼠以及 Satb2 中的所有 SCPN 来确定发育时间最后，在目标 3 中，我们使用亚群特异性转基因 Cre 系进行过表达。将研究 SCPN 轴突靶向 Satb2 功能丧失和获得的情况。 Satb2 靶基因的错误表达是否会改变 SCPN 对脑干和脊髓靶标的靶向。我们的工作将共同深入探讨转录调控何时以及如何控制的机制 SCPN 分段“身份”为后续分子识别提供了机械框架控制与大脑下目标的分段适当的 SCPN 连接。