Differential surface activation of the A1 domain of von Willebrand factor.
Differential surface activation of the A1 domain of von Willebrand factor.
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DOI：
10.1116/1.4943618
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发表时间：
2016-06-11
期刊：
影响因子：
2.1
通讯作者：
Thomas WE
中科院分区：
文献类型：
--
作者：
Tronic EH;Yakovenko O;Weidner T;Baio JE;Penkala R;Castner DG;Thomas WE
当凝血蛋白血管性血友病因子（VWF）被化学物质、高剪切力或固定在表面上激活时，VWF与血小板受体糖蛋白Ibα（GPIbα）结合。通过表面固定激活VWF是心血管植入物失效的一个重要问题，但知之甚少。在这里，作者研究了一些或所有表面是否可以至少部分地通过影响VWF的固定GPIbα结合A1结构域的取向或构象来激活VWF。血小板结合到A1吸附到聚苯乙烯表面易位迅速在中等和高流量，但在低流量分离，而血小板结合到A1吸附到玻璃或组织培养处理的聚苯乙烯表面易位缓慢，并只在高流量分离。X-射线光电子能谱和构象独立的抗体报告可比A1量的所有表面上。飞行时间二次离子质谱（ToF-SIMS）和近边缘X射线吸收精细结构光谱表明三个表面上的取向差异，但都不能解释生物学数据。相反，ToF-SIMS数据和构象依赖性抗体的结合与组织培养聚苯乙烯，特别是玻璃的A1的替代更活化构象的稳定性是一致的。这些研究表明，不同的材料表面不同的影响吸附的A1结构域的构象和其生物活性。这在解释或设计表面吸附A1结构域的体外实验时很重要，并且也可能与血液接触生物材料相关。
The clotting protein von Willebrand factor (VWF) binds to platelet receptor glycoprotein Ibα (GPIbα) when VWF is activated by chemicals, high shear stress, or immobilization onto surfaces. Activation of VWF by surface immobilization is an important problem in the failure of cardiovascular implants, but is poorly understood. Here, the authors investigate whether some or all surfaces can activate VWF at least in part by affecting the orientation or conformation of the immobilized GPIbα-binding A1 domain of VWF. Platelets binding to A1 adsorbed onto polystyrene surfaces translocated rapidly at moderate and high flow, but detached at low flow, while platelets binding to A1 adsorbed onto glass or tissue-culture treated polystyrene surfaces translocated slowly, and detached only at high flow. Both x-ray photoelectron spectroscopy and conformation independent antibodies reported comparable A1 amounts on all surfaces. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and near-edge x-ray absorption fine structure spectra suggested differences in orientation on the three surfaces, but none that could explain the biological data. Instead, ToF-SIMS data and binding of conformation-dependent antibodies were consistent with the stabilization of an alternative more activated conformation of A1 by tissue culture polystyrene and especially glass. These studies demonstrate that different material surfaces differentially affect the conformation of adsorbed A1 domain and its biological activity. This is important when interpreting or designing in vitro experiments with surface-adsorbed A1 domain, and is also of likely relevance for blood-contacting biomaterials.