Effect of slip bonds due to type 2B von Willebrand Disease on platelet adhesion, aggregation, and contractile forces

2B 型冯维勒布兰德病导致的滑移键对血小板粘附、聚集和收缩力的影响

• 批准号: 10525260
• 负责人: Ava Marie Obenaus
• 金额: $ 4.34万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-16 至 2023-12-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10525260
• 关键词: Actins; Adhesions; Affect; Affinity; Area; Binding; Biological Assay; Biomechanics; Biophysics; Blood; Blood Coagulation Disorders; Blood Platelet Disorders; Blood Platelets; Blood Proteins; Blood specimen; Calcium Signaling; Cells; Cytoskeleton; Defect; Development; Diagnosis; Diagnostic Procedure; Exposure to; Fibrillar Collagen; Functional disorder; Future; Glass; Glycoprotein Ib; Glycoproteins; Goals; Hemorrhage; Hemostatic function; Individual; Inherited; Integrins; Knowledge; Measures; Mechanics; Mediating; Methods; Microfluidic Microchips; Microfluidics; Molecular Weight; Mutate; Mutation; Myosin ATPase; Nature; Patients; Phenotype; Platelet Activation; Platelet aggregation; Play; Population; Process; Reporting; Research; Role; Site; Surface; Therapeutic; Thrombocytopenia; Thrombosis; Thrombus; Time; Vascular Endothelium; Whole Blood; Work; biomechanical test; cantilever; cost; flexibility; gain of function mutation; improved; interest; lonely individuals; novel diagnostics; platelet function; premature; receptor; response to injury; shear stress; transmission process; vascular injury; von Willebrand Disease; von Willebrand Factor; wound

PROJECT SUMMARY/ABSTRACT Von Willebrand Disease (VWD) is characterized by a defect in the blood protein von Willebrand Factor (VWF) and leads to uncontrolled bleeding. VWF is necessary for initial platelet tethering and subsequent platelet adhesion to the injured vasculature. Glycoprotein Ib (GPIb) is a receptor found on the platelet surface that recognizes the A1 domain of VWF. When the vascular endothelium is damaged, VWF binds to exposed fibrillar collagen and to GPIb, tethering the platelet to the surface. Then, cytoskeletal forces acting through integrin αIIBβ3 allow platelets to adhere and aggregate, forming a strong and stable platelet-rich plug. The GPIb-A1 bond forms under conditions of high shear and is characterized as a “catch” bond, meaning it has a longer lifetime under conditions of increased tensile force. In type 2B VWD, a gain-of-function mutation to VWF causes an increased affinity for platelet binding at low shear. The type 2B VWF mutation leads to spontaneous platelet binding and subsequently uncontrolled bleeding. Previous work has demonstrated that with type 2B VWD, VWF and GPIb no longer form a catch bond but instead a “slip” bond, which is characterized by a shorter bond lifetime under conditions of increased tensile force. Additionally, platelet cytoskeletal forces can act independently of integrin αIIBβ3 through the GPIb-A1 bond. However, prior work has failed to fully explain how slip bonds in type 2B VWD affect the mechanics of platelet adhesion and platelet plug formation. I hypothesize that changes in the force- lifetime relationship of GPIb-A1 bonds due to type 2B VWD will affect platelet adhesion and aggregation due to an inability to withstand cytoskeletal forces. Platelet adhesion and contractile force will be measured at the single platelet level using flexible, cantilever-like nanoposts, while the contractile force generated by a platelet aggregate will be quantified using a microfluidic device. Using these methods, I can characterize how the biomechanics of platelet plug formation are affected by type 2B VWD, further explaining the bleeding phenotype. In the future, this knowledge relating to hemostasis initiation can be utilized to diagnose or treat type 2B VWD.

项目摘要/摘要 Von Willebrand病(VWD)的特征是血液蛋白von Willebrand因子(VWF)缺陷 并导致失控出血。VWF对于最初的血小板捆绑和随后的血小板是必要的 粘连到受损的血管系统。糖蛋白Ib(GPIB)是一种存在于血小板表面的受体 识别VWF的A1域。当血管内皮细胞受损时，VWF与暴露的纤维结合 胶原蛋白和GPIB，将血小板捆绑在表面。然后，细胞骨架作用力通过整合素αIIBβ3发挥作用 让血小板黏附和聚集，形成强大而稳定的富含血小板的塞子。GPIB-A1键形成 在高剪切条件下，它的特征是一种“捕捉”键，这意味着在 拉力增加的条件。在2B型VWD中，功能获得突变到VWF会导致 低切变率下与血小板结合的亲和力。2B型VWF突变导致自发性血小板结合和 随后失控出血。以前的工作已经证明，对于2B型VWD、VWF和GPIB 不再形成Catch键，而是“滑移”键，其特征是在以下情况下键寿命较短 拉力增加的条件。此外，血小板细胞骨架作用力可以独立于整合素发挥作用。 αIIbβ3通过GPIB-A1键。然而，以前的工作未能完全解释2B型VWD中的滑移结合 影响血小板黏附和血小板堵塞形成的机制。我假设原力的变化- 2B型VWD引起的GPIB-A1键寿命关系将影响血小板黏附和聚集 由于无法承受细胞骨架的力量。将测量血小板粘附力和收缩力 在单个血小板水平上，使用灵活的悬臂式纳米孔，而由 血小板聚集物将使用微流控装置进行量化。使用这些方法，我可以描述如何 2B型VWD对血小板聚集的生物力学影响，进一步解释了出血的原因 表型。在未来，这种与止血开始有关的知识可用于诊断或治疗类型 2B VWD。