Genetic Mechanisms of Polycystic Kidney Disease

描述（由申请人提供）：我们的研究项目集中在了解常染色体显性多囊肾病（ADPKD）的分子机制。ADPKD是一种异质性疾病。两个致病基因PKD1和PKD2的突变导致相似的临床表现，这两个基因分别定位于染色体16p 13.3和4q21-23。尽管在了解其致病产物多囊蛋白-1和-2的发病机制和某些功能方面已经取得了相当大的进展，但由PKD1或PKD2突变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。为了进一步剖析和表征多囊毒素的生物学功能，我们已经开始在小鼠模型中产生具有“条件”靶向突变的Pkd2，该突变可以被CreloxP和flpe - frt介导的系统在时间和空间上诱导。同时，我们还建议创建一个具有等位基因（Pkd2flox stop）的小鼠模型，其中Pkd2的表达可以使用Cre-loxP系统有条件地恢复。与我们的其他Pkd突变模型（如null-Pkdl和/或-Pkd2）一起，有条件的“打开”和“关闭”模型将为我们解决几个不清楚的问题提供无与伦比的工具。这些问题包括，在携带Pkd2可恢复等位基因的小鼠中，由Cre-loxP系统介导的多囊蛋白-2的恢复是否能够挽救囊性表型或在疾病模型中阻止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的外源性功能作用是什么，以及囊性的发生如何依赖于杂合性的丧失。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在小鼠胚胎发生和发育过程中多囊素-1和-2是否具有完全重叠的功能，以及具有反纯合子Pkdl和Pkd2的小鼠是否比单独使用任何一种小鼠导致更严重的发育缺陷。通过对这些小鼠及其衍生细胞系的研究，我们将进一步了解多囊素-2在囊肿形成的开始和进展以及肾上皮细胞生理调节中的作用。我们也将进一步了解多囊蛋白-1和-2在ADPKD膀胱形成过程中的关系，并有望为该病的治疗奠定基础。

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.