Huynh Khon, Nguyen Thi-Hiep, Nguyen Phuong Thao, Tran Ngoc Quyen, Vo Van Toi, Gyenes Marianna, Stoldt Volker R
Biomedical Engineering Department, International University, Vietnam National University.
Graduate School of Science and Technology Viet Nam, Vietnam Academy of Science and Technology.
Blood Coagul Fibrinolysis. 2018 Sep;29(6):488-495. doi: 10.1097/MBC.0000000000000744.
Shear stress can activate platelet integrin-mediated signaling that leads to shear-induced platelet aggregation (SIPA) and eventually contribute to acute myocardial infarction. The major platelet integrin αIIbβ3 is polymorphic at residue 33 [Leu33Pro (PlA) polymorphism]. The Pro33 isoform has been shown to have a prothrombotic phenotype. In this work, we studied the impact of Leu33/Pro33 polymorphism on the shear-induced integrin-mediated Src and FAK activation in platelets.
Platelets of both genotypes were placed on immobilized fibrinogen or heat activated BSA and were exposed to physiological (500/s) or abnormally high (5000/s) shear rates for 2-10 min. Platelets after exposure to shear were analysed for Src pY418 and FAK pY397 activities.
Whereas physiological shear stress does not affect platelet signaling, abnormally high-shear stress considerably elevates Src and FAK phosphorylation in both Pro33 and Leu33 platelets. Both under static and flow conditions, Pro33 platelets exhibited a significantly higher Src and FAK activities than Leu33 platelets. Interestingly, even in the absence of the αIIbβ3-fibrinogen interaction, we could detect a shear-induced integrin-mediated signaling of Src and FAK in platelets. In parallel experiments in which platelets were pretreated with abciximab, an integrin αIIbβ3 antagonist, activation of both kinases by shear was inhibited.
Taken together, our data indicates an important role of αIIbβ3 and shows that Leu33Pro polymorphism modulates the integrin-mediated Src and FAK signaling in platelets in response to shear stress.
剪切应力可激活血小板整合素介导的信号传导，导致剪切诱导的血小板聚集（SIPA），最终促成急性心肌梗死。主要的血小板整合素αIIbβ3在第33位残基处存在多态性[亮氨酸33脯氨酸（PlA）多态性]。已表明Pro33异构体具有促血栓形成表型。在本研究中，我们探讨了Leu33/Pro33多态性对剪切诱导的整合素介导的血小板中Src和粘着斑激酶（FAK）激活的影响。
将两种基因型的血小板置于固定化纤维蛋白原或热激活的牛血清白蛋白（BSA）上，并暴露于生理剪切速率（500/s）或异常高的剪切速率（5000/s）下2 - 10分钟。对暴露于剪切后的血小板进行Src pY_{418}和FAK pY_{397}活性分析。
生理剪切应力不影响血小板信号传导，而异常高的剪切应力会显著提高Pro33和Leu33血小板中Src和FAK磷酸化水平。在静态和流动条件下，Pro33血小板的Src和FAK活性均显著高于Leu33血小板。有趣的是，即使在不存在αIIbβ3 - 纤维蛋白原相互作用的情况下，我们仍能检测到血小板中剪切诱导的整合素介导的Src和FAK信号传导。在平行实验中，用整合素αIIbβ3拮抗剂阿昔单抗预处理血小板后，剪切对两种激酶的激活作用受到抑制。
综上所述，我们的数据表明αIIbβ3具有重要作用，并表明Leu33Pro多态性可调节血小板中整合素介导的Src和FAK信号传导以响应剪切应力。
