Investigation of a neuromesendodermal progenitor population in the posterior avian endoderm

禽类后内胚层神经中内胚层祖细胞群的研究

• 批准号: 10276499
• 负责人: Nandan L Nerurkar
• 金额: $ 39.88万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10276499
• 关键词: Adult; Atlases; Biochemical; Biophysics; Birds; Brain; Cell Line; Cells; Chick Embryo; Complex; Cues; Development; Developmental Biology; Dorsal; Ectoderm; Ectoderm Cell; Embryo; Embryology; Embryonic Development; Endoderm; Endoderm Cell; Genes; Germ Layers; Goals; Invaded; Investigation; Malignant Neoplasms; Mesenchyme; Mesoderm; Mesoderm Cell; Multipotent Stem Cells; Neural tube; Organ; Pathogenesis; Pattern; Population; Process; Regulation; Research; Shapes; Signal Transduction; Source; Specific qualifier value; Stereotyping; Surface; Time; Tissues; Totipotent; Tube; Work; cell behavior; epithelial to mesenchymal transition; experimental study; gastrulation; in vivo Model; notochord; novel; pluripotency; progenitor; programs; prospective; segregation; single-cell RNA sequencing; stem; stem cell population; stem cells; transcriptomics

PROJECT SUMMARY/ABSTRACT Transformation of the early embryo from a seemingly disorganized ball of stem cells to the complex and precisely patterned adult form requires stereotyped regulation cell behaviors via biophysical and biochemical cues. Using the chick embryo, the long term goals of my research program are to understand from a highly quantitative perspective how this is orchestrated. Approximately half of the lab focuses on mechanobiology of embryonic development, seeking to understand the forces that shape tissues and organs in the embryo and the cues that specify those forces. The remainder of the lab studies cell fate determination, either in the context of early brain development or in the developing gut. The present application stems from the latter. During embryonic development, one of the first major steps in lineage segregation is gastrulation, when a single totipotent layer of cells separates into three germ layers, endoderm, mesoderm, and ectoderm. While conventionally, it has long been accepted that all progenitors of each germ layer are generated only during gastrulation, recent studies have challenged this, identifying a multipotent progenitor population that persists after gastrulation ends in the tailbud. Within this population, known as neuromesodermal progenitors, a single cell can give rise to progeny that contribute to both notochord (mesoderm) and neural tube (ectoderm). While studying gut tube formation in the chick embryo, we recently identified a population of endoderm cells that line the ventral surface of the tailbud, and appear to undergo a widespread and previously unreported epithelial-to- mesenchymal transition (EMT). These cells invade the neighboring tailbud tissue, reaching as far as the dorsal surface of the tailbud. Importantly, cells can be seen dispersed throughout the region where neuromesodermal progenitors are known to reside, as well as in the neural tube and notochord. This suggests that these endodermal cells represent an unappreciated source of neuromesodermal progenitors, which, if they retain the ability to generate endodermal tissues as well, would be remarkable. The present application combines classical embryology approaches such as fate mapping and grafting experiments with gene misexpression and single-cell RNA Sequencing in an effort to make sense of the simple yet puzzling observation that endoderm cells undergo a localized EMT and invade the tailbud at a time when gastrulation is complete. The proposal aims to identify the tissues to which this prospective progenitor population contributes, and to construct a detailed single-cell transcriptomic atlas of this population, from which identity, regulatory circuits, and proposed lineage trajectories can be inferred. At the completion of the proposed work, we will have established a new in vivo model to study endodermal EMT, and potentially identified a novel stem cell population residing in the endoderm, with the ability to give rise to mesodermal and ectodermal cells. This stands in contrast to long-held notions of lineage segregation during embryonic development, and therefore has the potential to be transformative for the fields of developmental biology and stem cell reprogramming.

项目概要/摘要 早期胚胎从看似杂乱的干细胞球转变为复杂且 精确模式化的成人形态需要通过生物物理和生物化学来定型调节细胞行为 提示。我的研究计划的长期目标是使用鸡胚胎从高度了解 定量的角度来看这是如何精心策划的。大约一半的实验室专注于机械生物学 胚胎发育，寻求了解塑造胚胎组织和器官的力量， 指定这些力量的线索。实验室的其余部分研究细胞命运的决定，无论是在背景下 早期大脑发育或发育中的肠道。本申请源于后者。 在胚胎发育过程中，谱系分离的第一个主要步骤是原肠胚形成，当 单全能层细胞分为三个胚层：内胚层、中胚层和外胚层。尽管 按照惯例，长期以来人们一直认为每个胚层的所有祖细胞仅在 原肠胚形成，最近的研究对此提出了挑战，确定了持续存在的多能祖细胞群 原肠胚形成在尾芽结束后。在这个被称为神经中胚层祖细胞的群体中，有一个 细胞可以产生对脊索（中胚层）和神经管（外胚层）都有贡献的后代。尽管 通过研究鸡胚肠管的形成，我们最近发现了一群内胚层细胞，这些细胞排列在 尾芽的腹侧表面，并且似乎经历了广泛且先前未报道的上皮到- 间质转化（EMT）。这些细胞侵入邻近的尾芽组织，直至背侧 尾芽表面。重要的是，可以看到细胞分散在神经中胚层分布的整个区域。 已知祖细胞存在于神经管和脊索中。这表明这些 内胚层细胞是神经中胚层祖细胞的一个未被重视的来源，如果它们保留了 产生内胚层组织的能力也将是非凡的。本申请结合了 经典胚胎学方法，例如命运图谱和基因错误表达的嫁接实验 单细胞 RNA 测序，试图理解内胚层这一简单但令人费解的观察结果 原肠胚形成完成时，细胞经历局部 EMT 并侵入尾芽。提案 旨在确定该预期祖群体所贡献的组织，并构建一个 该群体的详细单细胞转录组图谱，其中包括身份、调节电路和拟议的 可以推测血统轨迹。在完成拟议的工作后，我们将建立一个新的 研究内胚层 EMT 的体内模型，并可能鉴定出存在于内胚层中的新型干细胞群 内胚层，具有产生中胚层和外胚层细胞的能力。这与长期以来的做法形成鲜明对比 胚胎发育过程中谱系分离的概念，因此有可能被 对发育生物学和干细胞重编程领域具有变革意义。