Role of PECAM-1 in the shear-stress-induced activation of Akt and the endothelial nitric oxide synthase (eNOS) in endothelial cells
Role of PECAM-1 in the shear-stress-induced activation of Akt and the endothelial nitric oxide synthase (eNOS) in endothelial cells
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DOI：
10.1242/jcs.02541
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发表时间：
2005-09-15
影响因子：
4
通讯作者：
Busse, R
中科院分区：
文献类型：
--
作者：
Fleming, I;Fisslthaler, B;Busse, R
流体剪应力作用于内皮细胞，可引起一氧化氮(NO)的生成和内皮型一氧化氮合酶(ENOS)的磷酸化。切应力还引起内皮蛋白酪氨酸磷酸化的增强，特别是那些位于细胞-细胞接触附近的蛋白。由于这些内皮细胞-细胞接触的主要成分是血小板内皮细胞黏附分子-1(PECAM-1)，我们评估了PECAM-1在eNOS激活中的作用。在人内皮细胞中，剪切力诱导PECAM-1的酪氨酸磷酸化，并增强PECAM-1与eNOS的结合。切应力刺激内皮细胞可诱导Akt和eNOS的磷酸化以及AMP激活的蛋白激酶(AMPK)的磷酸化。酪氨酸激酶抑制剂PP1可阻断切应力诱导的PECAM-1的酪氨酸磷酸化以及Akt和eNOS的丝氨酸磷酸化，但不影响AMPK的磷酸化。使用siRNA方法下调PECAM-1可以减弱切应力诱导的Akt和eNOS的磷酸化，以及切应力诱导的循环GMP水平的积聚，而切应力诱导的AMPK的磷酸化保持不变。在PECAM-1缺陷小鼠产生的内皮细胞中，也观察到Akt和eNOS(但不是AMPK)磷酸化和NO产生的类似的减弱。这些数据表明，切应力诱导的内皮细胞Akt和eNOS的激活是由PECAM-1的酪氨酸磷酸化调控的，而切应力诱导的AMPK的磷酸化是由另一条信号通路控制的。
The application of fluid shear stress to endothelial cells elicits the formation of nitric oxide (NO) and phosphorylation of the endothelial NO synthase (eNOS). Shear stress also elicits the enhanced tyrosine phosphorylation of endothelial proteins, especially of those situated in the vicinity of cell-cell contacts. Since a major constituent of these endothelial cell-cell contacts is the platelet endothelial cell adhesion molecule-1 (PECAM-1) we assessed the role of PECAM-1 in the activation of eNOS. In human endothelial cells, shear stress induced the tyrosine phosphorylation of PECAM-1 and enhanced the association of PECAM-1 with eNOS. Endothelial cell stimulation with shear stress elicited the phosphorylation of Akt and eNOS as well as of the AMP-activated protein kinase (AMPK). While the shear-stress-induced tyrosine phosphorylation of PECAM-1 as well as the serine phosphorylation of Akt and eNOS were abolished by the pre-treatment of cells with the tyrosine kinase inhibitor PP1 the phosphorylation of AMPK was unaffected. Downregulation of PECAM-1 using a siRNA approach attenuated the shear-stress-induced phosphorylation of Akt and eNOS, as well as the shear-stress-induced accumulation of cyclic GMP levels while the shear-stress-induced phosphorylation of AMPK remained intact. A comparable attenuation of Akt and eNOS (but not AMPK) phosphorylation and NO production was also observed in endothelial cells generated from PECAM-1-deficient mice. These data indicate that the shear-stress-induced activation of Akt and eNOS in endothelial cells is modulated by the tyrosine phosphorylation of PECAM-1 whereas the shear-stress-induced phosphorylation of AMPK is controlled by an alternative signaling pathway.