Role of polycystin-1 in centrosome duplication and cell cycle control

描述（由申请人提供）：迄今为止，在ADPKD囊肿中发现的显著遗传异质性的分子机制仍然未知。类似的核型改变导致了基因组的不稳定性。我们的总体假设是，PC1失调通过改变正常的中心体功能和细胞周期进程，导致基因组不稳定，从而促进了囊性超增殖过程。我们的初步结果发现了支持这一主张的有力证据。特异性siRNA介导的PC1抑制在体外改变了细胞周期进程和中心体扩增，这一发现在人类ADPKD肾组织中得到证实。中心体完整性的丧失与剧烈的基因组不稳定性有关。本应用的实验重点是阐明这些新发现背后的分子机制。第一个具体目的是确定PC1失调是否导致参与中心体复制过程的蛋白质的异常调节。第二个特定目的是评估PC1敲低可能导致干扰正常细胞分裂周期进程的分子机制。第三个具体目的是利用含有强力霉素诱导的小鼠PKD1特异性siRNA的转基因小鼠模型，在体内表征PC1敲低在囊性增生和中心体扩增中的作用。总之，这些新的研究将扩大药物开发的治疗性细胞周期靶点，以及我们对疾病过程的理解。

DESCRIPTION (provided by applicant): To date, the molecular mechanisms responsible for the remarkable genetic heterogeneity found in ADPKD cysts remain unknown. Similar karyotypic alterations have been described consequently to genomic instability. Our overall hypothesis is that PC1 disregulation contributes to the cystogenic hyperproliferative process by altering normal centrosomal functions and cell cycle progression, leading to genomic instability. Our preliminary results have uncovered strong evidence in support of this proposition. Specific siRNA- mediated inhibition of PC1 altered cell cycle progression and centrosome amplification in vitro, a finding corroborated in human ADPKD renal tissues. Loss of centrosome integrity was associated with dramatic genomic instability. The experimental focus of this application is to elucidate the molecular mechanisms underlying these novel findings. The first specific Aim is to determine whether PC1 disregulation causes an abnormal modulation of the proteins involved in the centrosome duplication process. The second specific Aim is to evaluate molecular mechanisms by which PC1 knockdown may cause interference with the normal cell division cycle progression. The third specific Aim is to characterize in vivo the role of PC1 knockdown in cystic hyperproliferation and centrosome amplification, using a transgenic mouse model containing a doxycyclin inducible siRNA specific for murine PKD1. Taken together, these novel studies will expand therapeutic cell cycle targets for drug development, as well as our understanding of the disease process. PUBLIC HEALTH RELEVANCE The elucidation of mechanisms underlying ADPKD hyperproliferative processes will help the understanding of the events triggering cystogenesis. Our study will contribute to ongoing efforts assessing the therapeutic potential for cell cycle inhibitors in the treatment of ADPKD.