VEGF诱导内皮细胞分泌Clusterin的作用及其机制

Clusterin is a multifunctional secretory protein that is expressed in many different types of cells including vascular endothelial cells. However, the mechanism underlying its secretory regulation is unclear. In a previous study, we isolated VEGF-induced secretome in endothelial cells and identified Clusterin as an abundant component in VEGF-induced secretome. Further, we found that Clusterin is involved in the multimer formation of vWF, a key molecule for the formation of endothelial Weibel-Palade body. In this application, we will study the interaction between Clusterin and vWF, and analyze the role of the interaction in Clusterin localization in WPB and the multimer formation of vWF. In addition, we will use living system to visualize the secretory process of Clusterin. Further, we will use in vitro and in vivo models to investigate the role of Clusterin in VEGF-mediated endothelial inflammatory response and angiogenic function. This study may reveal the mechanism underlying Clusterin secretion in endothelial cells and deepen our understanding of VEGF effects and regulations.

Clusterin是一种多功能分泌蛋白，表达于包括血管内皮细胞在内的多种类型细胞中，但其分泌调控机制尚不清晰。前期我们发现Clusterin的分泌受到重要血管内皮细胞生长因子VEG F调控，并发现它定位于内皮细胞特有分泌囊泡WP小体（Weibel-Palade body)，且参与WP小体 形成分子vWF的多聚体形成。本申请将研究Clusterin与vWF之间的相互作用，明确这种相互作 用对Clusterin在WP小体定位及vWF多聚体形成的影响；研究VEGF诱导的Clusterin分泌过程及 调控，明确Clusterin在VEGF诱导内皮细胞分泌vWF、激发内皮细胞炎症反应，以及血管新生反 应等功能中的作用。最后，还将研究VEGF诱导Clusterin分泌的病理生理意义。本研究不仅有 望揭示内皮细胞Clusterin分泌调控机制，且能增进对VEGF功能及其调控的理解。

内皮细胞分泌是血管损伤的第一道防线，而VEGF调控内皮分泌。 Weibel Palade bodies（WP小体）是血管内皮细胞特有的分泌囊泡，储存多种凝血（如von Willebrand因子，VWF）和炎症相关因子等，在血管损伤早期起关键保护作用。本项目在研究VEGF诱导的内皮细胞分泌组学时意外发现clusterin分子是一个新的WP小体成分，并存在与VWF存在相互作用。明确了clusterin与VWF结合的部位，发现Clusterin下调导致VWF多聚体水平降低，进一步发现发现Clusterin缺陷小鼠的出血时间相比野生小鼠延长及血栓形成障碍。最后，ADAMTS13介导Clusterin对VWF多聚形态的调控。本研究的成果将对一些血管损伤、出血疾病的防治具有潜在意义，目前在整理成文。