Genetic Mechanisms of Polycystic Kidney Disease

描述(申请人提供)：我们的研究计划集中在了解常染色体显性遗传性多囊肾病(ADPKD)的分子机制。ADPKD是一种异质性疾病。分别位于染色体16p13.3和4q21-23的两个致病基因PKD1和PKD2的突变导致相似的临床表现。尽管在研究多囊蛋白-1和多囊蛋白-2的致病机制和某些功能方面已经取得了很大进展，但由导致膀胱发生的PKD1或PKD2突变所引起的细胞事件以及多囊蛋白之间的功能关系仍然不清楚。为了进一步分析和表征多囊蛋白的生物学功能，我们已经开始建立具有PKD2“条件性”靶向突变的小鼠模型，这种突变可以由CreloxP和Flpe-FRT介导的系统在时间和空间上诱导。同时，我们还建议建立一个带有等位基因(Pkd2flx Stop)的小鼠模型，在该模型中，可以使用Cre-loxP系统有条件地恢复PKD2的表达。与我们的其他PKD突变模型，如Null-Pkd1和/或-PKD2，有条件的“开启”和“关闭”模型将提供我们需要的无与伦比的工具来解决几个不清楚的问题。这些问题包括：在携带PKD2可恢复等位基因的小鼠中，通过Cre-loxP系统介导的多囊蛋白-2的恢复是否能够挽救疾病模型中的囊性表型或阻止ADPKD的进展(例如，Pkd2WS25/-)；ADPKD中囊性疾病的进展速度有多快；多囊蛋白-2在肾外的作用是什么；以及囊变的发生如何依赖于杂合性的丢失。此外，具有基因组合等位基因系列的小鼠将使我们能够确定多囊蛋白-1和-2在小鼠胚胎发生和发育过程中是否具有完全重叠的功能，以及携带反式纯合Pkd1和PKD2的小鼠是否会导致比单独存在的小鼠更严重的发育缺陷。通过研究这些小鼠及其衍生的细胞系，我们将进一步深入了解多囊蛋白-2在囊性形成的发生和发展中的作用以及肾上皮细胞的生理调节。我们还将进一步了解多囊蛋白-1和多囊蛋白-2在ADPKD囊变过程中的关系，并有望为ADPKD的治疗奠定基础。

DESCRIPTION (provided by applicant): Our research program centers on understanding the molecular mechanism of autosomal dominant polycystic kidney disease (ADPKD). ADPKD is a heterogeneous disease. Mutations in two causal genes, PKD1 and PKD2, which have been mapped to chromosomes 16p 13.3 and 4q21-23, respectively, result in similar clinical manifestations. Although considerable progress toward understanding the disease mechanisms and some functions of its causal gone products, polycystin-1 and -2 has been made, the cellular events resulting from PKD1 or PKD2 mutations that cause cystogenesis and the functional relationship between the polycystins remain poorly defined. To further dissect and characterize the biological functions of the polycystins, we have begun to generate mouse models with a 'conditional' targeted mutation in Pkd2 that can be induced temporally and spatially by CreloxP and Flpe-FRT-mediated systems. In parallel, we have also proposed to create a mouse model with an allele (Pkd2flox stop) in which the expression of Pkd2 can be conditionally restored using the Cre-loxP system. Together with our other Pkd mutant models, such as the null-Pkdl and/or -Pkd2, the conditionally 'turn-on' and 'turn-off' models will provide the incomparable tools we need to address several unclear questions. These include whether or not the restoration of polycystin-2 mediated by the Cre-loxP system in mice bearing the Pkd2 restorable allele is able to rescue cystic phenotypes or arrest the progression of ADPKD in the disease model (e.g., Pkd2WS25/-), how fast is the progressional rate of cystic disease in ADPKD, and what are the extrarenal functional roles of polycystin-2, and how does the cystogenesis depend on loss of heterozygosity. Moreover, the mice with a genetically combinatorial allelic series will enable us to determine if polycysin-1 and -2 have a completely overlapping functions during mouse embryogenesis and development, and if the mice with trans-homozygous Pkdl and Pkd2 leads to severer developmental defects than those seen in either alone. By studying these mice and the cell lines derived from them, we will gain further insights into the role of polycystin-2 in the initiation and progression of cyst formation and the regulation of renal epithelial cell physiology. We will also learn more about the relationship between polycystin-1 and -2 during the cystogenesis of ADPKD, and will hopefully be able to establish a therapeutic basis for this disease.