FOCAL ADHESION COMPLEXES AND LUNG ENDOTHELIAL APOPTOSIS

描述(摘自申请者的摘要)：细胞凋亡导致血管 细胞损伤，并调节血管细胞的生长对损伤的反应。这个 研究人员描述了由肺内皮细胞凋亡引起的 腺苷+同型半胱氨酸(A/H)。他们的初步结果表明，A/H 导致所选组件的重新定位和caspase诱导的降解 焦点粘连(FA)复合体。FA复合体是酪氨酸磷酸化蛋白 介导细胞外基质与细胞相互作用的聚集体 细胞骨架。初步结果表明，蛋白质酪氨酸磷酸酶 (PTPase)活性早期参与A/H诱导内皮细胞损伤的机制 细胞凋亡。蛋白质酪氨酸磷酸化对维持 细胞骨架的组织和细胞黏附以及细胞-底物的破坏 黏附可引起锚定依赖性细胞的凋亡。他们建议说 A/H激活PTP1B，而PTP1B进而使焦点粘连(FA)去磷酸化 激酶，允许DNA片断和细胞凋亡的解离。vbl.使用 牛肺动脉内皮细胞的培养及A/H模型的建立 细胞凋亡，他们将决定：1)A/H是否导致酪氨酸 FA复合体蛋白质组分的去磷酸化和解离；2) FA复合体的破坏是否需要激活PTPase；3)是否 天然FA激酶或其组成蛋白磷酸化形式的过表达 FA激酶钝化以及是否过度表达一个显性的负性片段 FA激酶增强A/H诱导的细胞凋亡和局部黏附的破坏 以及4)细胞凋亡是否与再定位和 PTP1B激活增强及PTP1B过表达是否促进A/H FA复合体的凋亡和破坏。这些研究将提供重要的 FA复合体酪氨酸磷酸化在血管紧张素系统中的作用 对细胞凋亡的调控。对内皮细胞凋亡的了解将使 调节血管损伤和修复的方法的发展。

DESCRIPTION (Adapted from the Applicant's Abstract): Apoptosis causes vascular cell injury and regulates vascular cell growth in response to injury. The investigators have described lung endothelial cell apoptosis caused by adenosine plus homocysteine (A/H). Their preliminary results indicate that A/H causes relocalization and caspase-induced degradation of selected components of focal adhesion (FA) complexes. FA complexes are tyrosine phosphorylated protein aggregates which mediate the interaction of extracellular matrix with cell cytoskeleton. Preliminary results indicate that protein tyrosine phosphatase (PTPase) activity is involved early in the mechanism of A/H-induced endothelial cell apoptosis. Protein tyrosine phosphorylation is important to maintenance of cytoskeletal organization and cell adhesion, and disruption of cell-substratum adhesion can cause apoptosis of anchorage-dependent cells. They propose that A/H activates PTP1B which, in turn, dephosphorylates focal adhesion (FA) kinase, allowing dissociation of DNA fragmentation and apoptosis. Using cultured bovine pulmonary artery endothelial cells (BPAEC) and the A/H model of apoptosis, they will determine: 1) whether A/H causes tyrosine dephosphorylation and dissociation of protein components of FA complexes; 2) whether PTPase activation is required for FA complex disruption; 3) whether over-expression of native FA kinase or a constitutively phosphorylated form of FA kinase blunts and whether over-expression of a dominant negative fragment of FA kinase enhances A/H-induced apoptosis and disruption of focal adhesion complexes; and 4) whether apoptosis is associated with relocalization and enhanced activation of PTP1B and whether over-expression of PTP1B enhances A/H apoptosis and disruption of FA complexes. These studies will provide important insights into the role of tyrosine phosphorylation of FA complexes in regulation of apoptosis. Understanding of endothelial apoptosis will allow development of means of regulating vascular injury and repair.