miRNA Regulation of Aquaporin 1 Modulates Vascular Remodelling during Cirrhosis

描述(由申请人提供)：肝硬变和门静脉高压症是显著的发病率、死亡率和医疗费用的原因。由于肝纤维化和病理性血管生成是相互依赖的过程，而且肝内皮细胞(LEC)的侵袭是血管生成的必要步骤，因此研究肝内皮细胞侵袭的详细分子机制具有重要意义。LEC的侵袭受局部细胞体积调节和渗透压驱动的膜形状改变等机制的调节。水通道蛋白-1(Aquaporin-1，AQP1)是一种完整的膜水通道，在肝硬变时在LEC中显著过度表达，促进肝硬变微环境的侵袭。AQP1在肝硬变期间在LEC中过度表达的确切机制在很大程度上仍未被研究。基于选定的背景理论和新的初步数据，我们提出了一个中心假设，即肝硬变期间局部渗透压波动通过改变渗透压敏感的、AQP1调节的miRNAs、miR-666和miR-708的水平来驱动AQP1的过度表达，从而促进肝硬变期间的动态膜泡形成、LEC侵袭和血管生成。为了实现我们的总体目标，我们将采用互补的分子、细胞生物学和体内方法来建立AQP1过表达的机制以及AQP1调节miRNAs在LEC侵袭、血管生成和肝硬变中的作用。目的研究局部渗透压如何沉默miR-666和miR-708，从而增加LEC中AQP1的表达。目的研究miR-666和miR-708对人晶状体上皮细胞血管生成表型的影响。目的在体内检测miR-666和miR-708过表达对血管生成和纤维化的影响。这些结果将从机械上扩展初步的发现，并提供关于渗透压敏感的、基于miRNA的机制的新信息，控制AQP1的过度表达，并最终可能为针对AQP1及其分子调节因子的抗血管生成治疗奠定基础。

DESCRIPTION (provided by applicant): Cirrhosis and portal hypertension are the cause of significant morbidity, mortality, and healthcare expenditures. Since hepatic fibrosis and pathological angiogenesis are processes that are mutually dependent and since liver endothelial cell (LEC) invasion is a requisite step for angiogenesis, studies of the detailed molecular mechanisms governing LEC invasion are of great importance. LEC invasion is modulated by mechanisms involving localized cell volume regulation and osmotically driven membrane shape changes. Aquaporin-1 (AQP1) is an integral membrane water channel that is dramatically overexpressed in LEC during cirrhosis and facilitates invasion through the cirrhotic microenvironment. The precise mechanisms responsible for the overexpression of AQP1 in LEC during cirrhosis remain largely uninvestigated. Based on selected background rationale and novel preliminary data, we propose the central hypothesis that local osmotic fluctuation during cirrhosis drives AQP1 overexpression by altering levels of the osmotically sensitive, AQP1 regulatory miRNAs, miR-666 and miR-708, thereby promoting dynamic membrane blebbing, LEC invasion, and angiogenesis during cirrhosis. To accomplish our overall objective, we will employ complementary molecular, cell biologic, an in vivo approaches to establish the mechanism of AQP1 overexpression and the effect of AQP1 regulatory miRNAs on LEC invasion, angiogenesis, and cirrhosis. Aim I will focus on how local osmolality silences miR- 666 and miR-708 to subsequently increase AQP1 in LEC. Aim II investigates the effects of miR-666 and miR- 708 on the angiogenic phenotype of LEC. Aim III tests the effects of miR-666 and miR-708 overexpression on angiogenesis and fibrosis in vivo. The results will mechanistically extend the preliminary findings and provide novel information regarding the osmotically sensitive, miRNA-based mechanisms, controlling AQP1 overexpression and may ultimately produce the foundation for anti-angiogenic therapies targeting AQP1 and its molecular regulators in cirrhosis.