Identifying human-specific neural progenitors and their role in neurodevelopment

项目摘要/摘要 人类拥有高度先进的认知能力和运动技能，这些特征反映在 我们中枢神经系统(CNS)的大小和细胞多样性。我的总体目标是分析和比较 人类、非人灵长类和啮齿动物的祖细胞多样性，从而确定 增加了人类中枢神经系统的细胞多样性和大小。作为我博士后研究的一部分，我收集并分析了 具有良好特性的人类和小鼠脊髓运动的高时间分辨率单细胞RNA-SEQ数据 神经元(MN)谱系，这导致了一种分子上不同的、人类特有的(即，在 小鼠)运动神经元前体(HsPMN)细胞型。我发现hsPMN经历了延迟和延长 神经再生，使总MN产量增加~2倍。这项拟议的研究旨在描述他们是如何 通过将单细胞RNA-SEQ与MN谱系相结合，有助于MN谱系的种群规模和亚型多样性 星形胶质细胞长期共培养或异种移植谱系标记的人类细胞。第二，建议的 研究将进一步研究hsPMN细胞的进化及其基因表达程序，通过a)确定 是否在东半球猴子(即猕猴)中发现了同源细胞类型，以及b)识别和功能 测试产生hsPMN特异性基因表达模式的新进化的基因调控元件。 最后，我将开发一种3D脊椎器官体外分化系统，该系统包含空间图案的腹侧 和背侧脊椎谱系，使用一套标准的分化条件，可以应用于人类， 猕猴和老鼠细胞。这最后一个目标将扩大比较调查的范围，以涵盖 多脊椎谱系，从而为未来的研究开辟了新的途径和假设，以及提供了 更全面的脊髓发育体外模型系统。洞察、协议和数据 这项研究产生的结果将使我们能够对人类神经前体进行有价值的比较分析 以及人类特有的祖细胞如何对中枢神经系统的大小和细胞多样性做出贡献 发展。此外，这些研究和数据将构成我作为 独立调查员，虽然允许我扩大我的研究培训以包括不同的物种宿主， 模型系统和广泛的实验和计算技术。

PROJECT SUMMARY/ABSTRACT Humans have highly advanced cognitive abilities and motor skills, characteristics which are reflected in the enlarged size and cell diversity of our central nervous system (CNS). My overall goal is to profile and compare progenitor cell diversity in humans, non-human primates and rodents, and thereby identify the origins of increased cell diversity and size of the human CNS. As part of my postdoctoral research, I collected and analyzed high-temporal-resolution single-cell RNA-seq data of the well characterized human and mouse spinal motor neuron (MN) lineage, which led to the identification of a molecularly distinct, human-specific (i.e., not found in mouse) motor neuron progenitor (hsPMN) cell type. I found that hsPMNs undergo delayed and protracted neurogenesis, increasing total MN output by ~2-fold. The proposed study aims to characterize how they contribute to the population size and subtype diversity of the MN lineage by combining single-cell RNA-seq with long-term astrocyte co-culture or xeno-transplantation of lineage-labeled human cells. Second, the proposed study will further investigate the evolution of hsPMN cells and their gene expression program by a) determining whether an orthologous cell type is found in old-world monkeys (i.e., macaque), and b) identifying and functionally testing newly evolved gene regulatory elements that give rise to hsPMN-specific gene expression patterns. Finally, I will develop a 3D spinal organoid in vitro differentiation system that harbors spatially patterned ventral and dorsal spinal lineages, using a standard set of differentiation conditions that can be applied to human, macaque, and mouse cells. This last aim will broaden the scope of comparative investigations to encompass multiple spinal lineages, thus opening up new avenues and hypotheses for future research, as well as providing a more comprehensive in vitro model system of spinal cord development. The insights, protocols, and data generated from this study will enable and provide valuable comparative analyses into human neural progenitor diversity and how human-specific progenitors contribute to the size and cell diversity of the CNS during development. Furthermore, these studies and data will form the foundation of my research agenda as an independent investigator, while allow me to broaden my research training to include a diverse host of species, model systems and a wide array of experimental as well as computational techniques.