Regulatory mechanisms for retinal ganglion cell genesis

项目摘要/摘要 了解各种神经元是如何从神经前体细胞分化出来的，对于理解 中枢神经系统的生物学和疾病，包括视网膜。所有视网膜细胞类型，包括 七种类型的神经元和Müler神经胶质细胞，由视网膜前体细胞在 发展。任何视网膜细胞类型的缺陷都会导致视力丧失，甚至失明。在这些人中 各种视网膜细胞，视网膜神经节细胞(RGC)是唯一的输出神经元，它将轴突发送到 视神经形式的大脑中视网膜的靶区。我们的长期目标是获得一个 全面了解调控RGC形成的遗传和分子机制 发展。三种转录因子在RGC分化中起关键调节作用；ATOH7功能 上游使RPC能够胜任RGC谱系，而POU4F2和IsL1向下游发挥作用 促进RGC差异化。在上一个供资周期中，我们首次确定POU4F2和ISL1 足以指明研资局的命运，并促进它们的差异化，进一步澄清和确立 这两个因素在RGC的发生中起着关键作用。尽管我们和其他人取得了进展，但少校 我们对研资局的发展仍存有疑问。具体地说，目前还不清楚是什么导致了 ATOH7-表达RPC的独特方式使RGC从中产生RGC，RGC特异性基因是如何被激活的，什么 ATOH7在这些过程中扮演的具体角色，以及RGC前体一旦致力于它们的命运，如何进一步 分化为成熟的、有功能的RGC。在这项提案中，我们的目标是解决这些重要问题。我们的 最重要的假设是，表观遗传景观的变化是导致 RGC发生的不同阶段进展。因此，研究表观遗传景观是如何 在RGC形成过程中影响基因表达的进化将是这一提议的中心主题。我们的 围绕这一主题设计的具体目标包括：1)研究研资局的性质- 通过克隆谱系分析、表达谱分析和表观基因组学调查；2)调查 表观遗传景观通过RGC分化的进展和确定RGC特异的增强子 3)对RGC特异性增强子的功能进行实验评估和表征。总而言之， 这些目标涉及RGC形成的遗传和表观遗传基础。预期的结果将是 扩大我们对视网膜RPC向RGC转变过程中的分子事件的认识 发展。它们还将帮助我们定义将干细胞重新编程为RGC的要求，这是 与开发RGC相关疾病的治疗方法高度相关。因此，我们提出的研究在以下方面具有重要意义 既促进了视网膜发育的基础研究，又为临床应用提供了知识。

Project Summary/Abstract Understanding how the various neurons differentiate from neural progenitor cells is essential for understanding both the biology and diseases of the central nervous system, including the retina. All retinal cell types, including the seven types of neurons and the Müller glial cells, arise from retinal progenitor cells (RPCs) during development. Defects in any of the retinal cell types can cause vision loss and even blindness. Among the various retinal cells, retinal ganglion cells (RGCs) are the only output neurons, which send axons to the retinorecipient target regions of the brain in the form of the optic nerve. Our long-term goal is to obtain a comprehensive understanding of the genetic and molecular mechanisms regulating RGC formation during development. Three transcription factors serve as key regulators in RGC differentiation; ATOH7 functions upstream to render RPCs competent for the RGC lineage, whereas POU4F2 and ISL1 function downstream to promote RGC differentiation. In the last funding cycle, we for the first time established that POU4F2 and ISL1 are sufficient to specify the RGC fate and promote their differentiation, further clarifying and establishing the critical roles these two factors play in RGC genesis. Despite the progress we and others have made, major questions remain in our understanding of RGC development. Specifically, it remains unclear what makes ATOH7-expressing RPCs unique so that RGCs arise from them, how RGC-specific genes are activated, what specific roles ATOH7 plays in these processes, and how RGC precursors, once committed to their fate, further differentiate into mature and functional RGCs. In this proposal, we aim to address these important issues. Our overarching hypothesis is that changes in the epigenetic landscape are the major mechanism underlying the progression of RGC genesis through the different phases. Thus, investigating how the epigenetic landscape evolves to influence gene expression during RGC formation will be the central theme of this proposal. Our specific aims, which are all designed around, this theme, include: 1) to investigate the properties of RGC- competent RPCs by clonal lineage analysis, expression profiling, and epigenomics survey; 2) to survey the progression of the epigenetic landscape through RGC differentiation and identify RGC-specific enhancers in the genome; and 3) to experimentally evaluate and characterize the function of RGC-specific enhancers. Collectively, these aims address the genetic and epigenetic basis underlying RGC formation. The expected results will expand our knowledge about the molecular events during the transition from RPCs to RGCs in retinal development. They will also help us to define the requirement for reprograming stem cells into RGCs, which is highly pertinent to developing treatment for RGC-related diseases. Thus, our proposed research is significant in both advancing basic research on retinal development and providing knowledge for clinical applications.