Origin and Regulation of Kidney Progenitor Cells

描述（由申请人提供）：在脊椎动物器官发生过程中，一个重要且反复出现的主题是单个或小群细胞（即祖细胞）的早期规范，这些细胞在发育后期产生特定的器官系统。例如，卵黄囊细胞的一个子集是胚胎造血细胞的第一个来源，特定的神经嵴谱系产生了周围神经系统的重要部分。然而，关于最早形成脊椎动物肾脏的细胞的数据很少。肾脏祖细胞的鉴定和表征是重要的，因为脊椎动物的肾脏是可再生的，但肾脏再生的分子机制在很大程度上是未知的。成人肾脏的再生细胞可能与胚胎中最早的肾脏祖细胞有关。本研究旨在确定产生脊椎动物肾脏的最早胚胎细胞（Aim 1），并确定Lim1和Pax8在肾脏发育中的作用（Aim 2）。我们将验证Lim1和Pax8是中胚层向肾限制性组织发展的调节因子的假设。此外，我们将确定化合物4-（苯基硫代）丁酸不仅在斑马鱼胚胎中，而且在器官培养中影响肾脏组织规格的作用（目的3）。我们使用斑马鱼和爪蟾胚胎，因为它们的遗传和胚胎学特征相互补充，并且哺乳动物模型的特征可以进行脊椎动物系统早期肾脏发育的实验研究。本提案中概述的目的结合实验胚胎学，分子生物学和最先进的显微镜来鉴定肾脏祖细胞。这些研究结果可直接应用于其他脊椎动物，特别是人类，用于描述影响肾限制性祖细胞分化的分子事件。这项研究与公众健康的相关性是脊椎动物肾脏是一个复杂的体内平衡器官，其功能是解毒血液，维持离子和水的平衡，调节激素的释放。肾脏形成或功能异常的生理后果往往是致命的，透析和器官移植是肾脏疾病唯一的长期治疗方法。未来对抗肾脏疾病的策略必须依赖于对导致肾脏形成的最早事件的基本理解。

DESCRIPTION (provided by applicant): An essential and recurring theme during vertebrate organogenesis is the early specification of single or small groups of cells (i.e., progenitors) that, later in development, give rise to specific organ systems. For example, a subset of yolk sac cells is the first source of embryonic hematopoietic cells and specific neural crest lineages give rise to significant portions of the peripheral nervous system. Little data exist, though, on the earliest cells that give rise to the vertebrate kidney. Identification and characterization of kidney progenitor cells is important because the vertebrate kidney is regenerative, but the molecular mechanisms of nephric regeneration are largely unknown. It is possible that regenerative cells of the adult kidney are developmental^ related to the earliest kidney progenitor cells in the embryo. This proposal aims to identify the earliest embryonic cells that give rise to the vertebrate kidney (Aim 1) and determine the role of Lim1 and Pax8 during kidney development (Aim 2). We will test the hypothesis that Lim1 and Pax8 are regulators of intermediate mesoderm progression to nephric restricted tissue. Moreover, we will determine the role the chemical compound, 4-(phenylthio)butyric acid plays in influencing nephric tissue specification not only in zebrafish embryos but also in organ culture (Aim 3). We use both zebrafish and Xenopus embryos because their genetic and embryological features complement each other and those of mammalian models to permit experimental investigation of early kidney development in a vertebrate system. The Aims outlined in this proposal combine experimental embryology, molecular biology, and state-of-the-art microscopy to identify kidney progenitor cells. Results of these investigations are directly translatable to efforts in other vertebrates, particularly humans for delineating molecular events that can influence kidney-restricted progenitor cell differentiation. The relevance of this research to public health is the vertebrate kidney is a complex homeostatic organ that functions to detoxify blood, maintain ion and water equilibrium, and regulate hormone release. The physiological consequences of abnormal kidney formation or function are frequently fatal, with dialysis and organ transplantation the only long-term treatments for kidney disease. Future strategies to fight kidney disease must rely on a fundamental understanding of the earliest events that lead to the formation of the kidney.