A role for p38 MAP kinase in platelet activation by von Willebrand factor
A role for p38 MAP kinase in platelet activation by von Willebrand factor
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DOI：
10.1160/th03-02-0083
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发表时间：
2004-01-01
影响因子：
6.7
通讯作者：
Torti, M
中科院分区：
文献类型：
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作者：
Canobbio, I;Reineri, S;Torti, M
血管性血友病因子（vonWillebrand factor，VWF）与膜GPIb-IX-V受体结合诱导的血小板活化涉及多条信号转导途径。其中，Fc γ RIIA的募集和激活以及磷脂酶A的刺激（2）代表了独立的事件，对于支持完全血小板应答同样重要。磷脂酶A（2）被钙激活，并通过MAP激酶磷酸化。在本研究中，我们发现VWF刺激p38 MAP激酶（p38 MAPK）快速和持续的磷酸化。体外激酶活性测定显示，VWF刺激的p38 MAPK磷酸化与激酶活性增加有关。VVVF与GP 1b-IX-V的结合，而不是与整合素α（IIb）β（3）的结合，是支持p38 MAPK磷酸化所必需的。用特异性单克隆抗体阻断膜Fc γ RIIA或用环氧合酶抑制剂阻止血栓素A（2）的合成都不影响VWF诱导的p38 MAPK激活。然而，p38 MAPK的磷酸化被酪氨酸激酶Syk抑制剂piceatannol阻止。用p38 MAPK抑制剂SB 203580处理血小板完全阻止VWF刺激的血小板聚集。抑制p38 MAPK可明显抑制VWF诱导的花生四烯酸释放。我们还发现，VWF诱导胞浆磷脂酶A磷酸化（2），这一过程被p38 MAPK抑制剂SB 203580阻止。这些结果表明，p38 MAPK是VWF诱导的血小板活化的Fc γ RIIA非依赖性途径中的关键元件，并且参与磷脂酶A（2）和花生四烯酸释放的刺激。
Platelet activation induced by von Willebrand factor (VWF) binding to the membrane GPIb-IX-V receptor involves multiple signal transduction pathways. Among these, recruitment and activation of the FcgammaRIIA and stimulation of phospholipase A(2) represent independent events equally essential to support a complete platelet response. Phospholipase A(2) is activated by calcium and by phosphorylation through MAP kinases. In this work, we found that VWF stimulated the rapid and sustained phosphorylation of p38 MAP kinase (p38MAPK). In vitro kinase assay revealed that VWF-stimulated phosphorylation of p38MAPK was associated with increased kinase activity. Binding ofVVVF to GPlb-IX-V, but not to integrin alpha(llb)beta(3), was required to support phosphorylation of p38MAPK. Neither the blockade of the membrane FcgammaRIIA by a specific monoclonal antibody or the prevention of thromboxane A(2) synthesis by cyclooxygenase inhibitors affected VWF-induced p38MAPK activation. However, phosphorylation of p38MAPK was prevented by the tyrosine kinase Syk inhibitor piceatannol. Treatment of platelets with the p38MAPK inhibitor SB203580 totally prevented VWFstimulated platelet aggregation. Moreover, release of arachidonic acid induced by VWF was strongly impaired by inhibition of p38MAPK. We also found that VWF induced phosphorylation of cytosolic phospholipase A(2), and that this process was prevented by the p38MAPK inhibitor SB203580. These results demonstrate that p38MAPK is a key element in the FcgammaRIIA-independent pathway for VWF-induced platelet activation, and is involved in the stimulation of phospholipase A(2) and arachidonic acid release.