Diversity Supplement: Novel Role of Nephron Epithelialization in Nuclear Signaling

项目摘要/家长资助摘要(2R01DK115655-04A1)：新角色 核信号中的肾单位上皮化 **R01项目摘要/摘要已修订，因此它们是可行的，因为我们的赠款预算是 全球NIDDK减少30%(预算期的第5年除 比1-4年每年减少12%)。 先天性肾脏和尿路畸形(CAKUT)是导致儿童终末期死亡的最常见原因。 阶段性肾病导致需要进行肾移植。它们出现在几乎2%的新生儿中，构成了 近四分之一的先天缺陷。然而，只有14%的病例有已知的遗传原因。许多CAKUT 病例的原因是肾单位的形成存在缺陷，而肾单位是由必需的上皮性小管组成的。 肾脏的正常功能。先前的研究表明，平面细胞极性(PCP)的破坏 途径或外囊囊泡复合体导致肾小管畸形，表明这些 正常的小管形成所需的组件。在我们之前的研究中，我们评估了小管形成如何 是通过PCP和胞外包囊复合体独立促进的。我们研究了不同的模型， Daam1，一种福尔曼蛋白，它组装肌动蛋白细丝作为Wnt/Plane细胞极性途径的一部分，以及 Dnmbp/Tuba调节胞外囊泡靶向，通过促进 肾单位祖细胞之间的细胞间接触。我们发现了一种利用WNT/PCP的新机制 Forin蛋白Daam1通过以下途径驱动肾单位祖细胞之间的细胞连接形成以产生小管 聚合肌动蛋白以稳定粘附性连接处的钙粘附素。此外，我们的结果表明，外囊- 相关组分Dnmbp有助于靶向连接组分以启动这些细胞的形成 肾单位祖细胞之间的联系。尽管取得了这些进展，但我们并不了解细胞的形成-- 细胞接触对大鼠肾小管上皮化和形态发生的影响 发育中的肾单位。为了解决这一重大问题，我们将以我们的重要发现为基础 评估细胞连接形成如何影响肾小管的发育：1)确定细胞连接形成如何影响肾小管的发育 Daam1和Dnmbp之间的相互作用调节肾单位祖细胞和 2)确定DAAM1‘S在连接形成中的作用是否调节β-连环蛋白的连接与Wnt 在肾脏形成过程中的信号作用。总体而言，本申请中提出的实验将促进新的 理解细胞如何相互作用和沟通以实现与多个 器官系统。对参与肾脏发育的细胞生物学机制的定量评估是一种 新的研究领域，将有助于对上皮化和形态发生机制有价值的见解 潜在的小管生成过程。

PROJECT SUMMARY/ ABSTRACT OF PARENT GRANT (2R01DK115655-04A1): NOVEL ROLE OF NEPHRON EPITHELIALIZATION IN NUCLEAR SIGNALING **R01 Project Summary/Abstract has been revised so that they are feasible, given that our grant budget was subjected to a global NIDDK reduction of 30% (the 5th year of the budget period was eliminated in addition to a 12% cut from each of years 1-4). Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of pediatric end- stage renal disease resulting in the need for kidney transplant. They occur in almost 2% of births, making up nearly one-fourth of all birth defects. However, only 14% of cases have a known genetic cause. Many CAKUT cases result from defects in the formation of nephrons, which are composed of epithelial tubules that are required for the proper function of the kidney. Prior studies indicate that disruption of either the planar cell polarity (PCP) pathway or exocyst vesicle complex result in malformation of the nephric tubules, indicating that these components are required for proper tubule formation. In our previous studies, we evaluated how tubulogenesis is facilitated through the PCP and exocyst complexes independently. We investigated distinct models by which Daam1, a formin protein that assembles actin filaments as part of the Wnt/planar cell polarity pathway, and Dnmbp/Tuba, which regulates exocytic vesicle targeting, facilitate tubulogenesis by promoting the generation of cell-cell contacts between nephron progenitor cells. We discovered a novel mechanism that utilizes the Wnt/PCP formin protein Daam1 to drive cell junction formation between nephron progenitor cells to generate tubules by polymerizing actin to stabilize cadherin at adherens junctions. Additionally, our results indicate that the exocyst- associated component Dnmbp facilitates the targeting of junctional components to initiate formation of these cell contacts between nephron progenitors. Despite this progress, we do not understand how the formation of cell- cell contacts influences the developmental processes of tubule epithelialization and morphogenesis in developing nephrons. To address this significant question, we will build upon on our important discoveries to evaluate how cell junction formation impacts the development of the nephric tubules by: 1) Identifying how the interaction between Daam1 and Dnmbp regulates cell-cell contact formation between nephron progenitors and 2) Determining whether Daam1's role in junction formation regulates beta-catenin's junctional versus Wnt signaling roles during nephrogenesis. Overall, the experiments proposed in this application will facilitate a new understanding of how cells interact and communicate to carry out tubulogenesis that has relevance in multiple organ systems. The quantitative evaluation of cell biological mechanisms involved in nephric development is a new area of study that will contribute valuable insights into epithelialization and morphogenesis mechanisms underlying tubulogenic processes.