The Role of Basa Bodies in Wnt Signaling

描述（由申请人提供）：肾囊肿的形成是终末期肾功能衰竭的主要原因，鉴于这种疾病的治疗选择有限，了解其细胞基础至关重要。来自综合征和非综合征形式的囊肿形成的数据，如多囊肾病（PKD）、肾病（NPH）和Bardet-Biedl综合征（BBS），已经产生了重要的见解，并具有新的治疗方法的潜力。体外和体内研究表明，肾感觉纤毛的主要作用和假设，这些结构感知细胞外液信号已经获得了显著的势头。然而，细胞外信号的性质和作用仍然存在。最近的证据表明，纤毛和基底体负责转导形态发生信号。与这一观点一致，我们的初步数据表明，基底体的破坏会影响Wnt信号的传播，并且这种突变与非规范（β -连环蛋白独立）Wnt信号通路的成员发生遗传相互作用。在此，我们建议研究肾囊性疾病与Wnt信号传导之间的联系。首先，我们将建立Bbs1、Bbs4和Bbs6特异性切除小鼠的肾脏表型，所有这些基因都与睫状体/基底体功能有关，并通过lacZ报告基因监测肾脏发育过程中β -连环蛋白的活性。同时，为了探索基底体在常见肾脏疾病中的潜在作用，我们将通过在BBS突变系中引入杂合的Pkd1或Pkhdl空等位基因来探索BBS和PKD之间可能的协同作用，并确定是否存在遗传相互作用。其次，我们将研究基底体突变体和抑制剂中Wnt缺陷的生化性质，并确定一系列Wnt反应蛋白（如b-catenin和disheveled）的行为和细胞分布。最后，我们将结合强大的体外Wnt反应分析的力量，以及最近大量富集新型纤毛和基础体蛋白的研究，以确定纤毛中调节细胞内Wnt反应的新成分。通过Wnt信号建立基底体和纤毛之间的联系代表了肾囊性疾病的潜在范式转变，并可能导致一种全新的治疗和预防方法。

DESCRIPTION (provided by applicant): The formation of renal cysts is a leading cause of end-stage renal failure, and given the limited management options for this disorder, understanding its cellular basis is of paramount importance. Data from syndromic and non-syndromic forms of cyst formation, such as the polycystic kidney diseases (PKD), nephronophthisis (NPH) and Bardet-Biedl syndrome (BBS), have yielded important insights and hold the potential for new therapeutic approaches. In vitro and in vivo studies have indicated a major role for renal sensory cilia and the hypothesis that these structures sense extracellular fluid signaling has gained significant momentum. However, the nature and effect of the extracellular signal(s) remains. Recent evidence suggests that the cilium and basal body are responsible for transducing morphogenetic signals. In agreement with this notion, our preliminary data suggest that disruption of the basal body affects the propagation of Wnt signaling and that such mutations interact genetically with members of the non-canonical (beta-catenin independent) Wnt signaling pathway. Here we propose to investigate the link between renal cystic disease and Wnt signaling. First, we will establish the renal phenotype of mice ablated specifically for Bbs1, Bbs4 and Bbs6, all of which have been implicated in ciliary/basal body function, and monitor the activity of beta-catenin during renal development by means of a lacZ reporter. In parallel, to explore the potential role of the basal body in common renal disease, we will explore the possible synergy between BBS and PKD by introducing a heterozygous Pkd1 or Pkhdl null allele in Bbs mutant lines and determine whether there is genetic interaction. Second, we will investigate the biochemical nature of the Wnt defect in basal body mutants and suppressants and determine the behavior and cellular distribution of a series of Wnt-responsive proteins such as b-catenin and Dishevelled. Finally, we will combine the power of robust in vitro Wnt response assays with recent studies that heavily enriched for novel ciliary and basal body proteins to identify new components of the cilium that regulate the intracellular Wnt response. Establishing the link between the basal body and the cilium with Wnt signaling represents a potential paradigm shift in renal cystic disease and will likely lead to a profoundly novel means of approaching treatment and prevention.