How Tetraspanins Regulate Vascular Morphogenesis

血管形态发生需要适当的内皮细胞（EC）粘附和迁移。 跨膜蛋白四跨膜蛋白广泛存在于内皮细胞中。我们 最近的发现表明，四跨膜蛋白CD 82抑制新生血管形成， 病理性刺激我们的研究还表明，这种四跨膜蛋白通过以下方式抑制新生血管形成： 抑制EC运动，通过限制EC粘附来抑制EC运动， 通过促进细胞粘附分子（CAM）的内吞作用和防止细胞粘附， 脂筏在质膜上的聚集。明确和完整的机制， 控制CD 82介导的病理性血管生成和EC运动的抑制，然而， 在分子、细胞和生物体水平上仍然是未知的。 为了阐明CD 82如何抑制新生血管形成，我们假设，在细胞水平上， CD 82下调动态EC-基质粘附，这是正确EC运动所需的。 在分子水平上，CD 82通过以下方式减少EC表面的功能性细胞粘附蛋白： 改变了膜脂的分子结构， EC。在这个项目中，我们将首先确定CD 82选择性抑制 病理性新生血管形成我们将确定CD 82效应物， 病理性新生血管形成，确定CD 82是否限制血管生成信号， 优先影响病理性新生血管形成，并评估CD 82对EC的影响。 主要影响病理性新血管形成的事件。其次，我们将确定 CD 82改变细胞粘附分子运输的机制， CD 82对其在EC中的内吞、再循环和外泌体释放的影响。最后我们将 确定CD 82如何组织EC的膜微区，通过评估的活动， 鞘糖脂代谢酶对CD 82去除的影响，神经节苷脂的调节作用 以及神经节苷脂在CAM运输和CD 82- 介导的EC运动和病理性血管生成的抑制。因此，本项目的目标 是为了了解CD 82如何在分子水平上选择性地抑制病理性血管生成， 细胞和有机体水平。 通过这些研究，我们将描绘四跨膜蛋白调节血管的机制 形态发生，建立病理性血管生成和膜之间的新范式 微区组织，并揭示了控制EC之间串扰的信号轴 运动和EC粘附。从深入的机理研究出发， 了解CD 82的独特功能，这将最终导致开发 对病理性血管生成的治疗手段。

Vascular morphogenesis requires proper endothelial cell (EC) adhesion and migration. Transmembrane proteins tetraspanins are abundantly and ubiquitously present in endothelia. Our recent finding indicates that tetraspanin CD82 inhibits neovascularization in response to pathological stimuli. Our study also revealed that this tetraspanin inhibits neovascularization by restraining EC movement, restrains EC movement by confining EC adhesions, and confines EC adhesion by facilitating the endocytosis of cell adhesion molecules (CAMs) and preventing the aggregation of lipid rafts at the plasma membrane. The explicit and complete mechanisms that govern CD82-mediated inhibitions of pathological angiogenesis and EC movement, however, still remain largely unknown at the molecular, cellular, and organism levels. To elucidate how CD82 inhibits neovascularization, we hypothesize that, at the cellular level, CD82 down-regulates the dynamic EC-matrix adhesion, which is needed for proper EC movement. At the molecular level, CD82 reduces the functional cell adhesion proteins at the EC surface by altering the molecular landscape of membrane lipids and subsequently the endocytic machinery of ECs. In this project, we will first determine the mechanism by which CD82 selectively restrains pathological neovascularization. We will identify the CD82 effecter(s) that specifically affects pathological neovascularization, determine if CD82 confines angiogenic signaling that preferentially affects pathological neovascularization, and assess the effect of CD82 on the EC event(s) that mainly affects pathological neovascularization. Secondly, we will determine the mechanism by which CD82 alters the trafficking of cell adhesion molecules by examining the effects of CD82 on their endocytosis, recycling, and exosomal release in ECs. Finally, we will determine how CD82 organizes the membrane microdomains of ECs by assessing the activities of glycosphingolipid-metabolic enzymes upon CD82 removal, the regulatory effects of gangliosides on membrane microdomains, and the roles of gangliosides in CAM trafficking and in CD82- mediated inhibitions of EC movement and pathological angiogenesis. Thus, the goal of this project is to understand how CD82 selectively restrains pathological angiogenesis at the molecular, cellular, and organism levels. From these studies, we will delineate the mechanisms by which tetraspanins regulate vascular morphogenesis, establish a novel paradigm between pathological angiogenesis and membrane microdomain organization, and reveal the signaling axis that governs the crosstalk between EC movement and EC adhesion. From the in-depth mechanistic study, we will develop an integrated understanding of the unique features of CD82, which will ultimately lead to the development of therapeutic mean against pathological angiogenesis.