Mechanisms of Polycystin and Cilia Function in ADPKD

描述(申请人提供)：人类多囊肾疾病和纤毛之间的功能联系部分是基于突变导致肾囊肿形成的基因和其蛋白产物在纤毛-基底体复合体中表达的基因之间的重叠。随着这两类基因中的任何一种发生突变，一种常见的表型--肾囊肿的出现，导致了一个概念性的方程，即受多囊蛋白-1(PC1)或多囊蛋白-2(PC2)丢失影响的细胞路径与那些结构完整的纤毛丢失后受影响的细胞路径。这一建议是基于我们新的观察结果，即如果结构完整的纤毛同时被消融，PKD1或PKD2失活后的囊泡形成明显放缓。这 在成年发病和早期发育的小鼠模型中都存在PKD1和PKD2的影响，并且与纤毛消融的遗传机制无关。这些发现为PC1/PC2复合体抑制的一条途径提供了遗传学证据，该途径需要完整的纤毛在没有PC1/PC2-纤毛依赖的囊激活(CDCA)途径的情况下产生最大的促囊信号。这项建议的目的是确定CDCA途径的组成部分。为了实现这一目标，我们将定义包囊进展的特定决定因素，其活性在多囊藻毒素失活后受到存在或不存在完整纤毛的调节。我们将使用一系列高度相关的体内小鼠模型，包括CDCA的所有阶段，以研究已知和新的候选CDCA途径。我们将用转录组和蛋白质组发现方法来补充这些定向研究。我们已经确定整合素信号是CDCA的候选活性。我们将探索多囊蛋白在纤毛整合素信号中的作用，并确定这一途径的哪些成分在纤毛中是活跃的。我们将使用细胞中的基因敲除和小鼠的条件敲除模型来确定整合素信号是否是CDCA的一个组成部分，如果是，我们将针对它进行治疗，以确定ADPKD的临床前疗效。整个计划提供了两个关于ADPKD发病机制的新发现，每个发现都有很大的翻译潜力。

DESCRIPTION (provided by applicant): The functional connection between human polycystic kidney diseases and cilia is based in part on the overlap between genes whose mutation results in kidney cyst formation and genes whose protein products are expressed in the cilia-basal body complex. The occurrence of a common phenotype, kidney cysts, following mutation in either of these classes of genes has led to a conceptual equation of cellular pathways affected by loss of polycystin-1 (PC1) or polycystin-2 (PC2) with those affected following loss of structurally intact cilia. This proposal is based on our novel observation that cyst formation following inactivation o either Pkd1 or Pkd2 is markedly slowed if structurally intact cilia are concomitantly ablated. This effect is present in adult onset and early developmental mouse models of both Pkd1 and Pkd2 and is independent of the genetic mechanism of cilia ablation. The findings provide genetic evidence for a pathway that is inhibited by the PC1/PC2 complex and that requires intact cilia to produce maximal cyst promoting signals in the absence of PC1/PC2-a Cilia Dependent Cyst Activating (CDCA) pathway. The objective of this proposal are to identify the components of the CDCA pathway. To achieve this objective, we will define the specific determinants of cyst progression whose activity following inactivation of polycystins is modulated by the presence or absence of intact cilia. We will use a highly correlated series of in vivo mouse models that subsume all stages of CDCA to investigate known and novel candidate CDCA pathways. We will complement these directed studies with transcriptomic and proteomic discovery approaches. We have identified integrin signaling as a candidate CDCA activity. We will explore the role of polycystins in integrin signaling in cilia and determine which components of this pathway are active in cilia. We will use gene knockdown in cells and conditional knockout models in mice to determine whether integrin signaling is a component of CDCA and if so, we will target it therapeutically to determine preclinical efficacy in ADPKD. The overall program offers two novel discoveries regarding the pathogenesis of ADPKD that each have substantial potential for translation.