Molecular Studies of Hemolytic Thrombosis

溶血性血栓形成的分子研究

• 批准号: 10405649
• 负责人: Miguel Angel Cruz
• 金额: $ 43.86万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10405649
• 关键词: Adhesions; Adsorption; Antibodies; Anticoagulation; Avidity; Binding; Biochemical; Blood; Blood Circulation; Blood Platelets; Coagulation Process; Complex; Complication; Cryoelectron Microscopy; Development; Devices; Environment; Exposure to; Extracorporeal Membrane Oxygenation; Fibrin; Fibrinogen; Fibrinolytic Agents; Formalin; Foundations; Glycoprotein Ib; Hemoglobin; Hemoglobin A; Hemoglobin concentration result; Hemolysis; Hemorrhage; Hemostatic Agents; Hemostatic function; Intervention; Investigation; Measures; Mediating; Molecular; Molecular Conformation; Monitor; Mus; Outcome; Pathology; Patients; Plasma; Process; Proteins; Publishing; Recombinant Proteins; Reporting; Risk; Risk Factors; Role; Surface; Testing; Therapeutic; Therapeutic Intervention; Thrombosis; Thrombus; Variant; Whole Blood; Work; age group; enhancing factor; mechanical circulatory support; mortality; novel therapeutic intervention; shear stress; targeted agent; targeted treatment; thrombotic; thrombotic complications; ventricular assist device; von Willebrand Disease; von Willebrand Factor; von Willebrand factor receptor

A major complication of mechanical circulatory support devices (MCSD) for multi-organ support is the dichotomous pathology of thrombosis and bleeding. Intravascular hemolysis associated with MCSD produces free hemoglobin (fHb). Adsorption of fibrinogen and von Willebrand factor (VWF) onto non-biological surfaces captures platelets that may aggregate. We reported that high levels of fHb increased VWF- mediated platelet adhesion and thrombus formation on fibrin(ogen)-coated surfaces at high shear stress. Importantly, fHb increased the flow-dependent adhesion of formalin fixed platelets to a VWF coated surface, suggesting that fHb directly enhances the VWF- glycoprotein (GP)Ib interaction. VWF deficiency or antibodies against GPIb block the enhancement of platelet adhesion by fHb, validating the role of VWF. Lastly, our identification of ultra large VWF (ULVWF) in whole blood exposed to fHb and high shear rates suggests that platelet derived ULVWF may contribute to the pathology of thrombosis in the presence of high levels of fHb. Together, these findings provide the first evidence that high levels of fHb are critical for VWF-mediated thrombosis on surfaces coated with fibrin(ogen), and that ULVWF multimers from shear-activated platelets may enhance thrombosis more robustly than plasma VWF in the presence of fHb. Our overarching hypothesis is that fHb targets VWF, including the platelet-derived VWF, to promote platelet adhesion via GPIb, and potentiate fibrin formation by facilitating the binding of VWF to fibrinogen. We propose molecular, biochemical, and structural studies to investigate the mechanisms by which fHb dysregulates the interactions between VWF, fibrin(ogen), and platelets. Aim 1 will investigate the contributions of platelet VWF vs. plasma VWF to thrombosis. We will test the hypotheses that fHb interaction with platelet VWF enhances platelet adhesion to fibrin(ogen) and potentiates fibrin formation more robustly than plasma VWF. Aim 2 will test the hypothesis that fHb-bound VWF has a conformation that favors platelet adhesion. Aim 3 will determine the mechanism by which fHb dysregulate VWF-fibrin(ogen) interaction. We will test the hypotheses that fHb promotes VWF-fibrin(ogen) association and modulates the VWF-mediated fibrin formation. These studies will describe new mechanisms related to thrombosis in patients on MCSD and identify new, potential targets for therapeutic interventions in fHb-induced thrombosis.

多器官的机械电路支撑设备（MCSD）的主要并发症 支持是血栓形成和出血的二分法病理学。血管内 与MCSD相关的溶血会产生游离血红蛋白（FHB）。吸附 纤维蛋白原和von Willebrand因子（VWF）捕获非生物表面 可能聚集的血小板。我们报告说，高水平的FHB增加了VWF- 纤维蛋白（OGE）涂在纤维蛋白（OGen）涂层表面的介导的血小板粘合剂和血栓形成 高剪切应力。重要的是，FHB增加了福尔马林的流动依赖性粘附 将血小板固定在VWF涂层表面上，这表明FHB直接增强了VWF- 糖蛋白（GP）IB相互作用。 VWF缺乏症或针对GPIB的抗体阻止 通过FHB增强血小板粘附，验证了VWF的作用。最后，我们的 在暴露于FHB和高剪切的全血中鉴定超大VWF（ULVWF） 费率表明血小板衍生的ULVWF可能有助于血栓形成病理 在高水平的FHB的情况下。这些发现一起提供了第一个证据 高水平的FHB对于涂有覆盖的表面上的VWF介导的血栓形成至关重要 纤维蛋白（OGEN），以及剪切激活血小板的ULVWF多元元素可能会增强 在FHB存在下，血栓形成比血浆VWF更健壮。我们的总体 假设是FHB针对VWF，包括血小板衍生的VWF，以促进 通过GPIB和潜在的纤维蛋白形成的血小板粘附，通过促进结合 VWF到纤维蛋白原。我们提出分子，生化和结构研究 研究FHB失调VWF之间相互作用的机制 纤维蛋白（OGEN）和血小板。 AIM 1将调查血小板VWF VS的贡献。 血浆VWF进行血栓形成。我们将测试FHB与血小板相互作用的假设 VWF增强了血小板对纤维蛋白（OGEN）和电纤维形成的粘合剂更多 比等离子VWF坚固。 AIM 2将检验以下假设，即FHB结合的VWF具有 有利于血小板粘附的构象。 AIM 3将确定该机制 FHB失调的VWF-纤维蛋白（OGEN）相互作用。我们将检验FHB的假设 促进VWF-纤维蛋白（OGEN）关联并调节VWF介导的纤维蛋白 格式。这些研究将描述与患者血栓形成有关的新机制 在MCSD上，确定FHB诱导的治疗干预措施的新的潜在目标 血栓形成。