Mechanosensory role endothelial cilia polycystic kidney

描述(申请人提供)：多囊肾病(PKD)是一种全身性肾病，以进行性双侧肾囊肿形成为特征，导致肾功能逐渐下降。虽然PKD通常被认为是一种肾脏疾病，但大多数PKD患者死于高血压、动脉瘤、出血等心血管并发症。然而，尽管NIH罕见疾病办公室承认PKD是一种孤儿遗传病，但对这些并发症的基础科学研究并未给予太多关注。至少在肾上皮细胞中，纤毛起机械感觉细胞器的作用，表达到纤毛上的多囊蛋白(PKD蛋白)起机械流体感觉分子的作用。最近的一项研究还表明，多囊蛋白定位于血管内皮细胞的纤毛。特别是，纤毛在内皮中的作用仍然很大程度上尚不清楚，尽管多囊蛋白表达的主要部位之一是心血管系统，包括内皮纤毛。本方案旨在研究机械流体传感中内皮细胞的生物物理特性。因此，我们建议研究机械感觉细胞器，即纤毛，如何调节血管内皮细胞内钙信号通路，以及这些传感器的故障如何导致血管功能缺陷。因此，这一建议解决了内皮纤毛在感知流体剪切力的机械能力中发挥重要作用的主要假设。为了验证这一假设，我们将利用缺乏纤毛功能(PKD1)和纤毛结构(Tg737)的主动脉内皮细胞，并已开始产生PKD1内皮细胞系。没有纤毛发育的Tg737orpk小鼠也表明血管异常。因此，特定目标1旨在生成和表征Tg737内皮细胞；特定目标2旨在鉴定PKD1和Tg737细胞对流体剪应力的敏感性。这些目的是为了了解纤毛和多囊纤毛分子作为1)流体流动传感器，2)钙稳态的调节器，和3)机械剪切应力通路的调节器的作用。总之，拟议的研究将提供关于内皮细胞的机械感觉纤毛如何改变心血管系统的更详细的信息。这些了解血液疾病的新方法属于NIH/NHLBI的探索/开发拨款申请范围。

DESCRIPTION (provided by applicant): Polycystic kidney disease (PKD) is a systemic nephropathy characterized by progressive bilateral renal cyst formation that results in a gradual decline in renal function. Although it is most commonly known as a kidney disease, the majority of patients with PKD die due to cardiovascular complications such as hypertension, aneurysm, hemorrhage, etc. Yet, not much attention is given to the basic science research on these complications, though the Office of Rare Diseases at the NIH recognizes PKD as an "orphan" genetic disease. At least in kidney epithelial cells, it has been shown that cilia function as mechanosensory organelles, and polycystins (PKD proteins), which are expressed to cilia, function as mechanical fluid sensory molecules. A recent study also shows that polycystins localize to the cilia of vascular endothelial cells. In particular, the roles of cilia in endothelia remain largely unknown, although one of the major sites of polycystin expression is in cardiovascular system, including in endothelial cilia. The present proposal is designed to study biophysical properties of endothelia in mechano-fluid sensing. We therefore propose to study how mechanosensory organelles, i.e. cilia, regulate the intracellular calcium-signaling pathway in vascular endothelia and how failure of these sensors leads to defects in vascular functions. Thus, this proposal addresses the main hypothesis that ENDOTHELIAL CILIA PLAY AN IMPORTANT ROLE IN THE MECHANICAL CAPACITY TO SENSE FLUID SHEAR STRESS. To evaluate the hypothesis, we will utilize aortic endothelial cells that lack ciliary function (Pkd1) and ciliary structure (Tg737) and have started to generate Pkd1 endothelial cell lines. The Tg737orpk mouse, which develops no cilia, also indicates vascular abnormalities. Specific aim 1 is thus designed to generate and characterize Tg737 endothelial cells; specific aim 2 is to identify the sensitivity of both Pkd1 and Tg737 cells to fluid shear stress. These aims are designated to understand the roles of cilia and polycystin ciliary molecules as 1) fluid-flow sensors, 2) regulators of calcium homeostasis, and 3) modulators of mechanical shear stress pathways. Together, the proposed studies will provide more detailed information on how mechanosensory cilia of endothelial cells can alter the cardiovascular system. These novel approaches to understanding blood disease falls within the scope of exploratory/development grant application to the NIH/NHLBI.