Huynh Khon C, Gyenes Marianna, Nguyen Thi-Hiep, Vo Toi Van, Stoldt Volker R
aBiomedical Engineering Department, International University, Vietnam National University, Ho Chi Minh City, Vietnam bDepartment of Hemostasis, Hemotherapy, and Transfusion Medicine, Heinrich Heine University Medical Center, Düsseldorf, Germany.
Blood Coagul Fibrinolysis. 2017 Jun;28(4):279-285. doi: 10.1097/MBC.0000000000000593.
: Shear stress alone can activate platelets resulting in a subsequent platelet aggregation, so-called 'shear-induced platelet aggregation'. In our work, we analyzed how differently elevated shear stress impacts the Src and focal adhesion kinase (FAK) activation in fibrinogen-adherent human platelets. We detected the extents of Src pY418 and FAK pY397 activations in platelets on immobilized fibrinogen and over BSA under shear conditions. Moreover, we analyzed the role of αIIbβ3 in the shear-induced platelet signaling by performing our experiments in the presence of the αIIbβ3-antagonist Abciximab. Abnormally high shear rates (5000 s) significantly increased the extent of phosphorylation of both tyrosine kinases after short (2 min) incubation time independently of the presence or absence of the integrin αIIbβ3 ligand, fibrinogen. We could see considerably greater Src activation on immobilized fibrinogen than on BSA, but the extent of FAK Y397 phosphorylation was independent on the matrix. Abciximab not only reduced the Src and FAK signaling in platelets exposed to 5000 s on immobilized fibrinogen, but in platelets exposed to 5000 s over BSA as well. Our data indicate that whereas Src activation under shear stress is dominantly ligand-dependent, FAK signaling seems to be mostly shear induced.
单纯剪切应力可激活血小板，导致随后的血小板聚集，即所谓的“剪切诱导的血小板聚集”。在我们的研究中，我们分析了不同程度升高的剪切应力如何影响纤维蛋白原黏附的人血小板中Src和黏着斑激酶（FAK）的激活。我们检测了在剪切条件下固定化纤维蛋白原上以及牛血清白蛋白（BSA）上血小板中Src pY418和FAK pY397的激活程度。此外，我们通过在αIIbβ3拮抗剂阿昔单抗存在的情况下进行实验，分析了αIIbβ3在剪切诱导的血小板信号传导中的作用。异常高的剪切速率（5000 s⁻¹）在短时间（2分钟）孵育后，无论整合素αIIbβ3配体纤维蛋白原是否存在，均显著增加了两种酪氨酸激酶的磷酸化程度。我们可以看到，固定化纤维蛋白原上的Src激活程度明显高于BSA上，但FAK Y397的磷酸化程度与基质无关。阿昔单抗不仅降低了在固定化纤维蛋白原上暴露于5000 s⁻¹的血小板中的Src和FAK信号，也降低了在BSA上暴露于5000 s⁻¹的血小板中的信号。我们的数据表明，虽然剪切应力下的Src激活主要依赖配体，但FAK信号似乎主要是由剪切诱导的。
