FOCAL ADHESION COMPLEXES AND LUNG ENDOTHELIAL APOPTOSIS

描述（改编自申请人的摘要）：细胞凋亡导致血管 细胞损伤并调节血管细胞生长以应对损伤。的 研究人员描述了由以下因素引起的肺内皮细胞凋亡： 腺苷加同型半胱氨酸（A/H）。他们的初步结果表明 A/H 导致所选成分的重新定位和半胱天冬酶诱导的降解 粘着斑（FA）复合物。 FA 复合物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。初步结果表明蛋白酪氨酸磷酸酶 (PTPase) 活性参与 A/H 诱导内皮细胞损伤机制的早期 细胞凋亡。蛋白质酪氨酸磷酸化对于维持 细胞骨架组织和细胞粘附，以及细胞基质的破坏 粘附可引起贴壁依赖性细胞凋亡。他们建议 A/H 激活 PTP1B，进而使粘着斑 (FA) 去磷酸化 激酶，允许 DNA 片段解离和细胞凋亡。使用 培养牛肺动脉内皮细胞（BPAEC）及其A/H模型 细胞凋亡时，他们将确定：1) A/H 是否导致酪氨酸 FA 复合物蛋白质成分的去磷酸化和解离； 2） FA 复合物破坏是否需要 PTPase 激活； 3）是否 天然 FA 激酶或组成型磷酸化形式的过度表达 FA 激酶钝化以及显性负片段是否过度表达 FA 激酶增强 A/H 诱导的细胞凋亡和粘着斑破坏 复合体； 4) 细胞凋亡是否与重定位相关 PTP1B 的激活增强以及 PTP1B 的过表达是否会增强 A/H 细胞凋亡和 FA 复合物的破坏。这些研究将提供重要的 深入了解 FA 复合物酪氨酸磷酸化的作用 细胞凋亡的调节。了解内皮细胞凋亡将有助于 开发调节血管损伤和修复的方法。

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.