Identification of a Small Molecule That Modulates Platelet Glycoprotein Ib-von Willebrand Factor Interaction
Identification of a Small Molecule That Modulates Platelet Glycoprotein Ib-von Willebrand Factor Interaction
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DOI：
10.1074/jbc.m111.311431
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发表时间：
2012-03-16
影响因子：
4.8
通讯作者：
De Maeyer, Marc
中科院分区：
文献类型：
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作者：
Broos, Katleen;Trekels, Mieke;De Maeyer, Marc
血管性血友病因子(VWF)A1与糖蛋白(GP)Ibα的相互作用在血栓形成过程中起着重要作用，主要发生在高切应力部位。这种相互作用的抑制剂可以在体内防止血小板依赖性血栓的形成，而不会出现重大出血并发症。然而，目前正在开发的抑制剂的大小和/或蛋白质性质限制了口服生物利用度和临床开发。因此，我们的目标是寻找一种干扰VWF-GPIBα结合的小分子蛋白质-蛋白质相互作用抑制剂。在用定位算法和分子动力学确定了VWF-A1和GPIBα表面可能的小分子结合口袋后，在这两个结合对上进行了高通量的分子对接。保留了一组在预测口袋中显示良好电子对接分数的化合物，以测试它们对VWF-GPIBα复合物形成的体外影响，通过这些化合物，我们确定了一种化合物，该化合物出人意料地刺激了Ristoctin辅因子ELISA中VWF-GPIBα的结合，并在动脉切变率下增加了全血中血小板与胶原的粘附性，但相反，它抑制了Ristoctin诱导的血小板聚集。所选择的化合物与预测的结合伙伴GPIBα的结合可以通过饱和传递差分核磁共振光谱进行确认。因此，我们明确地确定了一个调节VWF-GPIBα结合的小分子，现在将作为进一步研究和化学修饰的起点，以充分表征相互作用并操纵化合物的特定活性。
The von Willebrand factor (VWF) A1-glycoprotein (GP) Ib alpha interaction is of major importance during thrombosis mainly at sites of high shear stress. Inhibitors of this interaction prevent platelet-dependent thrombus formation in vivo, without major bleeding complications. However, the size and/or protein nature of the inhibitors currently in development limit oral bioavailability and clinical development. We therefore aimed to search for a small molecule protein-protein interaction inhibitor interfering with the VWF-GPIb alpha binding. After determination of putative small molecule binding pockets on the surface of VWF-A1 and GPIb alpha using site-finding algorithms and molecular dynamics, high throughput molecular docking was performed on both binding partners. A selection of compounds showing good in silico docking scores into the predicted pockets was retained for testing their in vitro effect on VWF-GPIb alpha complex formation, by which we identified a compound that surprisingly stimulated the VWF-GPIb alpha binding in a ristocetin cofactor ELISA and increased platelet adhesion in whole blood to collagen under arterial shear rate but in contrast inhibited ristocetin-induced platelet aggregation. The selected compound adhering to the predicted binding partner GPIb alpha could be confirmed by saturation transfer difference NMR spectroscopy. We thus clearly identified a small molecule that modulates VWF-GPIb alpha binding and that will now serve as a starting point for further studies and chemical modifications to fully characterize the interaction and to manipulate specific activity of the compound.