Mechanosensory role endothelial cilia polycystic kidney

描述（由申请人提供）：多囊肾病（Polycystic kidney disease， PKD）是一种以进行性双侧肾囊肿形成为特征，导致肾功能逐渐下降的全身性肾病。虽然最常见的是一种肾脏疾病，但大多数PKD患者死于心血管并发症，如高血压、动脉瘤、出血等。然而，尽管美国国立卫生研究院罕见病办公室将PKD视为一种“孤儿”遗传疾病，但对这些并发症的基础科学研究却没有给予太多关注。至少在肾上皮细胞中，纤毛具有机械感觉细胞器的功能，而表达到纤毛的多囊蛋白（PKD蛋白）具有机械流体感觉分子的功能。最近的一项研究也表明，多囊毒素定位于血管内皮细胞的纤毛。特别是，尽管多囊蛋白表达的主要位点之一是在心血管系统，包括内皮纤毛中，但纤毛在内皮中的作用仍然很大程度上未知。本研究旨在研究内皮细胞在机械流体传感中的生物物理特性。因此，我们建议研究机械感觉细胞器（如纤毛）如何调节血管内皮细胞内钙信号通路，以及这些传感器的失效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应力的机械能力中起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，并开始产生Pkd1内皮细胞系。Tg737orpk小鼠没有纤毛，也表明血管异常。因此，Specific aim 1被设计用于生成和表征Tg737内皮细胞；具体目的2是鉴定Pkd1和Tg737细胞对流体剪切应力的敏感性。这些目标旨在了解纤毛和多囊素纤毛分子的作用：1)流体流动传感器，2)钙稳态调节剂，3)机械剪切应力途径调节剂。总之，拟议的研究将提供内皮细胞机械感觉纤毛如何改变心血管系统的更详细信息。这些了解血液疾病的新方法属于NIH/NHLBI的探索性/开发资助申请范围。

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.