Harrington E O, Smeglin A, Newton J, Ballard G, Rounds S
Pulmonary/Critical Care Medicine Section, Providence Veterans Affairs Medical Center, and Department of Medicine, Brown University School of Medicine, Providence, Rhode Island 02908, USA.
Am J Physiol Lung Cell Mol Physiol. 2001 Feb;280(2):L342-53. doi: 10.1152/ajplung.2001.280.2.L342.
Adenosine and/or homocysteine causes endothelial cell apoptosis, a mechanism requiring protein tyrosine phosphatase (PTPase) activity. We investigated the role of focal adhesion contact disruption in adenosine-homocysteine endothelial cell apoptosis. Analysis of focal adhesion kinase (FAK), paxillin, and vinculin demonstrated disruption of focal adhesion complexes after 4 h of treatment with adenosine-homocysteine followed by caspase-induced proteolysis of FAK, paxillin, and p130(CAS). No significant changes were noted in tyrosine phosphorylation of FAK or paxillin. Pretreatment with the caspase inhibitor Z-Val-Ala-Asp-fluoromethylketone prevented adenosine-homocysteine-induced DNA fragmentation and FAK, paxillin, and p130(CAS) proteolysis. Asp-Glu-Val-Asp-ase activity was detectable in endothelial cells after 4 h of treatment with adenosine-homocysteine. The PTPase inhibitor sodium orthovanadate did not prevent endothelial cell retraction or FAK, paxillin, or vinculin redistribution. Sodium orthovanadate did block adenosine-homocysteine-induced FAK, paxillin, and p130(CAS) proteolysis and Asp-Glu-Val-Asp-ase activity. Thus disruption of focal adhesion contacts and caspase-induced degradation of focal adhesion contact proteins occurs in adenosine-homocysteine endothelial cell apoptosis. Focal adhesion contact disruption induced by adenosine-homocysteine is independent of PTPase or caspase activation. These studies demonstrate that disruption of focal adhesion contacts is an early, but not an irrevocable, event in endothelial cell apoptosis.
腺苷和/或同型半胱氨酸可导致内皮细胞凋亡，这是一种需要蛋白酪氨酸磷酸酶（PTPase）活性的机制。我们研究了粘着斑接触破坏在腺苷 - 同型半胱氨酸诱导的内皮细胞凋亡中的作用。对粘着斑激酶（FAK）、桩蛋白和纽蛋白的分析表明，在用腺苷 - 同型半胱氨酸处理4小时后粘着斑复合物被破坏，随后半胱天冬酶诱导FAK、桩蛋白和p130（CAS）发生蛋白水解。FAK或桩蛋白的酪氨酸磷酸化未观察到明显变化。用半胱天冬酶抑制剂Z - Val - Ala - Asp - 氟甲基酮预处理可防止腺苷 - 同型半胱氨酸诱导的DNA片段化以及FAK、桩蛋白和p130（CAS）的蛋白水解。在用腺苷 - 同型半胱氨酸处理4小时后，在内皮细胞中可检测到天冬氨酸 - 谷氨酸 - 缬氨酸 - 天冬氨酸酶活性。PTPase抑制剂原钒酸钠不能防止内皮细胞收缩或FAK、桩蛋白或纽蛋白的重新分布。原钒酸钠确实能阻断腺苷 - 同型半胱氨酸诱导的FAK、桩蛋白和p130（CAS）的蛋白水解以及天冬氨酸 - 谷氨酸 - 缬氨酸 - 天冬氨酸酶活性。因此，在腺苷 - 同型半胱氨酸诱导的内皮细胞凋亡中发生了粘着斑接触的破坏以及半胱天冬酶诱导的粘着斑接触蛋白的降解。腺苷 - 同型半胱氨酸诱导的粘着斑接触破坏与PTPase或半胱天冬酶激活无关。这些研究表明，粘着斑接触的破坏是内皮细胞凋亡中的一个早期但并非不可逆转的事件。
