Mechanisms of Polycystin and Cilia Function in ADPKD

描述（由申请人提供）：人类多囊肾疾病和纤毛之间的功能联系部分基于其突变导致肾囊肿形成的基因与其蛋白质产物在纤毛-基体复合体中表达的基因之间的重叠。在这些类别的基因中的任一个突变之后，发生常见的表型肾囊肿，这导致了受多囊蛋白-1（PC 1）或多囊蛋白-2（PC 2）损失影响的细胞途径与结构完整纤毛损失后受影响的细胞途径的概念方程。该建议是基于我们的新观察，即如果结构完整的纤毛同时消融，则Pkd 1或Pkd 2失活后的囊肿形成明显减慢。这 Pkd 1和Pkd 2的成年发病和早期发育小鼠模型中均存在这种效应，并且与纤毛消融的遗传机制无关。这些发现为一种途径提供了遗传学证据，该途径被PC 1/PC 2复合物抑制，并且需要完整的纤毛在没有PC 1/PC 2的情况下产生最大的囊肿促进信号-纤毛依赖性囊肿激活（CDCA）途径。本提案的目的是确定CDCA途径的组成部分。为了实现这一目标，我们将定义囊肿进展的特定决定因素，其活性在多囊蛋白失活后由完整纤毛的存在或不存在来调节。我们将使用一系列高度相关的体内小鼠模型来研究已知的和新的候选CDCA途径，这些模型涵盖了CDCA的所有阶段。我们将用转录组学和蛋白质组学的发现方法来补充这些定向研究。我们已经确定整合素信号传导作为候选CDCA活性。我们将探讨多囊蛋白在纤毛整合素信号传导中的作用，并确定该途径的哪些组分在纤毛中具有活性。我们将使用细胞中的基因敲除和小鼠中的条件性敲除模型来确定整合素信号传导是否是CDCA的一个组成部分，如果是，我们将在治疗上靶向它以确定ADPKD的临床前疗效。整个项目提供了两个关于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.