Mechanical regulation of von Willebrand factor

血管性血友病因子的机械调节

• 批准号: 10296176
• 负责人: Xiaohui Zhang
• 金额: $ 60.69万
• 依托单位: LEHIGH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10296176
• 关键词: Address; Adhesions; Affect; Amino Acids; Area; Binding; Binding Proteins; Biological Assay; Biomechanics; Biophysical Process; Blood Circulation; Blood Coagulation Disorders; Blood Platelets; Blood Vessels; Blood coagulation; C-terminal; Cardiovascular Diseases; Coagulation Process; Collagen; Complex; Defect; Detection; FDA approved; Fluorescence; Fluorescence Microscopy; Glycoprotein Ib; Hematological Disease; Hemorrhage; Human; Human body; Inherited; Investigation; Lead; Link; Location; Mechanics; Mediating; Modeling; Molecular; Mutate; Mutation; N-terminal; Nature; Pathogenesis; Pharmaceutical Preparations; Plasma Proteins; Platelet Glycoproteins; Platelet aggregation; Play; Polysaccharides; Population; Prevention; Prevention strategy; Property; Protein Biochemistry; Protein Chemistry; Proteins; Reagent; Regulation; Reporting; Role; Series; Serine; Sialic Acids; Site; Spectrum Analysis; Structure; Testing; Therapeutic; Threonine; Thrombosis; Thrombotic Thrombocytopenic Purpura; Variant; base; biophysical techniques; biophysical tools; design; disulfide bond; experimental study; gain of function mutation; glycoprotein receptor GPIb-IX; glycosylation; mechanical properties; models and simulation; molecular dynamics; molecular modeling; nanobodies; new therapeutic target; novel; novel therapeutic intervention; preempt; prevent; protein function; receptor; single molecule; success; von Willebrand Disease; von Willebrand Factor

PROJECT SUMMARY/ABSTRACT In human bodies, bleeding is stopped when a clot is formed at the site of vascular damage. Under rapid flow conditions, the plasma protein von Willebrand factor (VWF) plays an indispensable role in capturing both platelets and collagen on damaged vessel walls, allowing the formation of platelet plugs. The adhesion between VWF and platelets is mediated by the interaction between the A1 domain of VWF and the Ib chain of the platelet receptor GPIb-IX complex. Gain-of-function mutations in A1 that enhance this interaction lead to type 2B von Willebrand disease (VWD). Targeting the A1GPIb-IX interaction has been an emerging strategy to treat or preempt bleeding and thrombotic disorders, though success in this area has been very limited. The lack of progress is due largely to the enigmatic nature of how exactly A1 remains inactive in blood circulation and how it is instantly activated to bind to GPIb-IX upon bleeding. Our recent identification of an autoinhibitory module (AIM), consisting of N- and C-terminal flanking regions on A1 and their O-linked glycans, is crucial for understanding A1 mechanoactivation during bleeding. In addition, AIM can be unfolded by a tensile pulling force of 8 to 20 pN. Based on these preliminary discoveries, we hypothesize that O-linked glycan structures, particularly sialic acids, further stabilize AIM and contribute to the mechanical regulation of A1GPIb-IX binding and that modulating AIM’s mechanical properties can be utilized to treat or preempt blood diseases. We propose to test this potentially paradigm-shifting hypothesis using state-of-the-art analytical biophysical tools, including single-molecule force spectroscopy, single-molecule fluorescence microscopy and all-atom molecular dynamics simulation. Three specific aims will be pursued to test the hypotheses. Aim 1 is to characterize the structure and biomechanical properties of AIM. Aim 2 is to determine how autoinhibition is regulated by O-linked glycosylation in AIM. And Aim 3 is to investigate the role of AIM in type 2B VWD and therapeutic applications. Completion of the proposed studies will identify the key molecular and biophysical mechanisms underlying how AIM mechanically regulates VWF function and platelet binding and will aid in devising novel therapeutic strategies for the prevention and treatment of human blood disease.

项目概要/摘要 在人体中，当血管损伤部位形成凝块时，出血就会停止。急流下 在这种情况下，血浆蛋白血管性血友病因子 (VWF) 在捕获两者方面起着不可或缺的作用。 受损血管壁上的血小板和胶原蛋白，从而形成血小板栓塞。之间的附着力 VWF 和血小板是由 VWF 的 A1 结构域和 Ib 链之间的相互作用介导的 血小板受体 GPIb-IX 复合物。 A1 中增强这种相互作用的功能获得突变导致类型 2B 冯维勒布兰德病 (VWD)。针对 A1-GPIb-IX 相互作用已成为一种新兴的治疗策略 或预防出血和血栓性疾病，尽管这方面的成功非常有限。缺乏 进展很大程度上归因于 A1 到底如何在血液循环中保持不活跃状态以及它如何发挥作用的神秘本质。 出血后立即被激活与 GPIb-IX 结合。我们最近鉴定出一个自动抑制模块 (AIM)，由 A1 上的 N 端和 C 端侧翼区域及其 O 连接聚糖组成，对于 了解出血期间的 A1 机械激活。另外，AIM可以通过拉伸拉力展开 8 至 20 pN。基于这些初步发现，我们假设 O-连接聚糖结构， 特别是唾液酸，进一步稳定 AIM 并有助于 A1-GPIb-IX 结合的机械调节 调节 AIM 的机械性能可用于治疗或预防血液疾病。我们建议 使用最先进的分析生物物理工具来测试这一潜在的范式转变假设，包括 单分子力谱、单分子荧光显微镜和全原子分子 动力学模拟。将追求三个具体目标来检验这些假设。目标 1 是表征 AIM 的结构和生物力学特性。目标 2 是确定 O-连接如何调节自抑制 AIM 中的糖基化。目标 3 是研究 AIM 在 2B 型 VWD 和治疗应用中的作用。 完成拟议的研究将确定关键的分子和生物物理机制 AIM 机械调节 VWF 功能和血小板结合，有助于设计新的治疗方法 预防和治疗人类血液疾病的策略。