Expressed isolated integrin βI subunit cytodomain induces endothelial cell death secondary to detachment
Expressed isolated integrin βI subunit cytodomain induces endothelial cell death secondary to detachment
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DOI：
10.1160/th05-02-0108
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发表时间：
2005-11-01
影响因子：
6.7
通讯作者：
Rüegg, C
中科院分区：
文献类型：
--
作者：
Hasmim, M;Vassalli, G;Rüegg, C
据报道，在培养的内皮细胞中表达分离的β整联蛋白胞质结构域可诱导细胞脱离和死亡。为了测试细胞死亡是细胞脱离的原因还是结果，我们在培养的人脐静脉内皮细胞（HUVEC）中表达分离的整合素β 1胞质和跨膜结构域（CHI），并监测脱离、活力、半胱天冬酶活化和信号传导。CH I表达诱导剂量依赖性细胞脱离。24小时，超过90%的表达CH I的HUVEC被分离，但大部分存活（>85%）。未观察到半胱天冬酶原-8、-3和PARP裂解或ERK、PKB和I kappa-B磷酸化抑制的证据。半胱天冬酶抑制剂z-VAD不能阻止细胞脱离。然而，在48小时，表达CH I的细胞死亡超过50%。作为比较，胰蛋白酶介导的脱离导致时间依赖性细胞死亡，在脱离后24小时或更晚时，由caspase-3激活和ERK、PKB和I κ-B磷酸化抑制引起。用加强整联蛋白介导的粘附的试剂（即PMA、Src抑制剂PP 2和COMP-AngI）刺激HUVEC并不能阻止CHI-induced脱离。在体大鼠颈动脉内皮细胞表达CHI可引起内皮细胞脱落，并增加脱落细胞核DNA片段化。缺乏整合素胞质结构域（CH 2）的构建体在体外和体内对粘附和细胞活力没有影响。这些结果表明，孤立的β 1胞质结构域表达诱导半胱天冬酶非依赖性脱离的活内皮细胞和死亡是继发于脱离（即失巢凋亡）。他们还揭示了整合素在静止内皮细胞在体内的粘附和存活中的重要作用。
Expression of isolated beta integrin cytoplasmic domains in cultured endothelial cells was reported to induce cell detachment and death. To test whether cell death was the cause or the consequence of cell detachment, we expressed isolated integrin beta 1 cytoplasmic and transmembrane domains (CHI) in cultured human umbilical vein endothelial cells (HUVEC),and monitored detachment, viability, caspase activation and signaling. CH I expression induced dose-dependent cell detachment. At 24 h over 90% of CH I-expressing HUVEC were detached but largely viable(>85%). No evidence of pro-caspase-8,-3, and PARP cleavage or suppression of phosphorylation of ERK, PKB and I kappa-B was observed. The caspase inhibitor z-VAD did not prevent cell detachment. At 48 h, however, CH I-expressing cells were over 50% dead. As a comparison trypsin-mediated detachment resulted in a time-dependent cell death, paralleled by caspase-3 activation and suppression of ERK, PKB and I kappa-B phosphoyrylation at 24 h or later after detachment. HUVEC stimulation with agents that strengthen integrin-mediated adhesion (i.e. PMA the Src inhibitor PP2 and COMP-AngI) did not prevent CHI-induced detachment. Expression of CHI in rat carotid artery endothelial cells in vivo caused endothelial cell detachment and increased nuclear DNA fragmentation among detached cells. A construct lacking the integrin cytoplasmic domain (CH2) had no effect on adhesion and cell viability in vitro and in vivo. These results demonstrate that isolated beta 1 cytoplasmic domain expression induces caspase-independent detachment of viable endothelial cells and that death is secondary to detachment (i.e. anoikis). They also reveal an essential role for integrins in the adhesion and survival of quiescent endothelial cells in vivo.