流体剪应力对内皮细胞蛋白C的活化以及蛋白C受体和血栓调节蛋白表达的影响(英文)

Effects of Shear Stress on Protein C Activation,EPCR Expression And TM Expression in Endothelial Cells

蛋白C抗凝血途径在调节凝血系统的功能和炎症反应中起着重要作用。在体内,血流剪应力可引起内皮细胞结构的改变,调节基因和蛋白的表达。为了阐明流体剪应力对内皮细胞蛋白C途径的影响,我们研究了流体剪应力(2dyn/cm2和12dyn/cm2)对培养的人脐静脉内皮细胞(Human umbilical vein endothelial cells,HUVECs)蛋白C的活化以及表达内皮细胞蛋白C受体(Endothelial protein C receptor,EPCR)和血栓调节蛋白(Thrombo-modulin,TM)的影响。结果显示:(1)与静止状态细胞的基础水平相比,在剪应力或TNF-α单独作用后,EPCR的表达和蛋白C活化显著下调;在剪应力和TNF-α同时作用后,EPCR的表达和蛋白C活化与两种刺激单独作用后的水平相比,显著下调;(2)与静止状态细胞的基础水平相比,剪应力单独作用后TM的表达显著增加,而TNF-α单独作用后TM的表达则显著降低;剪应力和TNF-α同时作用后明显抵消了TNF-α刺激引起的TM降低;(3)与静止状态细胞的基础水平相比,剪应力或TNF-α单独作用后培养液里可溶性EPCR的水平显著增加;剪应力和TNF-α同时作用后培养液里可溶性EPCR的水平与两种刺激单独作用后的水平相比,明显下降。结论认为:血流剪应力对蛋白C活化有重要作用,这种作用可能是通过调节内皮细胞EPCR和TM的表达来实现的。

The protein C anticoagulant pathway plays a fundamental role in the control of coagulation system and inflammatory response. It has been well established that physiological levels of shear stress induce endothelial struc-tural change and modulate gene and protein expression. However, the role of shear stress in protein C pathway remains unknown. In the present study, we evaluated the effect of shear stress on the activation of protein C as well as on the expression of endothelial protein C receptor （EPCR） and thrombomodulin （TM） in human umbilical vein endothelial cells （HUVECs） which were exposed to TNF-α alone, shear stress alone, and TNF-α under shear stress. We found： （1） Either TNF-α or shear stress alone significantly reduced EPCR expression and protein C activation in HUVECs ; and simultaneous exposure of HUVECs to TNF-α and shear stress resulted in a further decrease of EPCR expression and protein C activation（P〈0. 05） ; （2） Simultaneous exposure of HUVECs to TNF-α and shear stress resulted in the increase of soluble EPCR level more significantly than did the exposure of HUVECs to either TNF-α or shear stress alone （P （0.05） ; （3） Shear stress significantly increased TM expression on HUVECs, whereas TNF-α inhibited TM expression; shear stress could strongly neutralize TNF-α＇s inhibitive effect on TM expression. We therefore conclude that shear stress may play an important role in protein C pathway, which may be fulifilled by regulating EPCR expression and TM expression in endothelial cells.