Thrombin inhibits nuclear factor κB and RhoA pathways in cytokine-stimulated vascular endothelial cells when EPCR is occupied by protein C
Thrombin inhibits nuclear factor κB and RhoA pathways in cytokine-stimulated vascular endothelial cells when EPCR is occupied by protein C
复制标题
DOI：
10.1160/th08-09-0568
复制
发表时间：
2009-03-01
影响因子：
6.7
通讯作者：
Rezaie, Alireza R.
中科院分区：
文献类型：
--
作者：
Bae, Jong-Sup;Rezaie, Alireza R.
蛋白C占据内皮蛋白C受体(EPCR)，使依赖于蛋白酶激活受体I(PAR-I)的凝血酶信号特异性从通透性增强转变为血管内皮细胞的屏障保护反应。在本研究中，通过监测细胞表面黏附分子(VICAM-I、ICAM-I和E-选择素)的表达、新分离的中性粒细胞与细胞因子刺激的内皮细胞的黏附、Rho家族小GTP酶家族的调节以及核因子-kappa B(NF-kappa B)途径的激活来评价凝血酶和凝血酶受体激动肽(TRAP)对肿瘤坏死因子(TNF)-α刺激的HUVECs的调节作用。结果分析表明，凝血酶和TRAP都能启动内皮细胞的促炎反应，因此在没有蛋白C突变体的情况下，PAR-I激动剂都不影响肿瘤坏死因子-α的促炎作用。然而，有趣的是，蛋白C突变体占据EPCR改变了凝血酶依赖PAR I的信号特异性，从而导致凝血酶抑制所有三种黏附分子的表达，以及中性粒细胞与肿瘤坏死因子-α激活的内皮细胞的结合。此外，与激活的蛋白C类似，凝血酶和TRAP都激活了RACI，并抑制了经蛋白C-S19SA预处理的细胞中RhoA和NF-kappa B通路的激活。根据这些结果，我们得出结论，当EPCR被蛋白C连接时，凝血酶对PAR-I的切割启动了抗炎反应，从而导致RACI的激活，并抑制了血管内皮细胞中RhoA和NF-kappa B的信号转导。
The occupancy of endothelial protein C receptor (EPCR) by protein C switches the protease activated receptor I (PAR-I)dependent signalling specificity of thrombin from a permeability enhancing to a barrier protective response in vascular endothelial cells. In this study, the modulatory effects of thrombin and thrombin receptor agonist peptides (TRAP) on tumour necrosis factor (TNF)-alpha-stimulated HUVECs in the absence and presence of the catalytically inactive protein C-S195A were evaluated by monitoring the expression of cell surface adhesion molecules (VICAM-I, ICAM-I and E-selectin), adhesion of freshly isolated neutrophils to cytokine-stimulated endothelial cells, regulation of the Rho family of small GTPases and the activation of nuclear factor-kappa B (NF-kappa B) pathway. The analysis of results indicate that both thrombin and TRAP initiate proinflammatory responses in endothelial cells, thus neither PAR-I agonist influenced the proinflammatory effects of TNF-alpha in the absence of the protein C mutant. Interestingly, however, the occupancy of EPCR by the protein C mutant switched the PAR-I-dependent signaling specificity of thrombin, thus leading to thrombin inhibition of the expression of all three adhesion molecules as well as the binding of neutrophils to TNF-alpha-activated endothelial cells. Furthermore, similar to activated protein C, both thrombin and TRAP activated RacI and inhibited the activation of RhoA and NF-kappa B pathways in response to TNF-alpha in cells pre-treated with protein C-S19SA. Based on these results we conclude that when EPCR is ligated by protein C, the cleavage of PAR-I by thrombin initiates antiinflammatory responses, thus leading to activation of RacI and inhibition of RhoA and NF-kappa B signalling cascades in vascular endothelial cells.