Structural origin of fibrin clot mechanical properties

纤维蛋白凝块机械性能的结构起源

• 批准号: 8903542
• 负责人: JOHN W WEISEL
• 金额: $ 40.8万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-12-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8903542
• 关键词: Affinity; Angioplasty; Applications Grants; Atomic Force Microscopy; Behavior; Binding; Biocompatible Materials; Biomechanics; Biomedical Research; Blood Platelets; Blood Vessels; Blood coagulation; Blood flow; Characteristics; Chemicals; Clinical; Clot retraction; Coagulation Process; Complex; Confocal Microscopy; Data; Dissociation; Elasticity; Electron Microscopy; Exhibits; Fiber; Fibrin; Fibrinogen; Health; Hemorrhage; Hemostatic Agents; Hemostatic function; Human; Individual; Kinetics; Lateral; Lead; Length; Lipoproteins; Maps; Measures; Mechanics; Microscopic; Modeling; Modification; Molecular; Molecular Structure; Mutation; Myocardial Infarction; Nodule; Obstruction; Outcome; Pharmacia brand of estropipate; Physiological; Plasma; Plasma Proteins; Play; Polymers; Property; Proteins; Reaction; Recombinants; Research; Resolution; Roentgen Rays; Role; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis; Stretching; Stroke; Structure; Surface; Therapeutic; Therapeutic Embolization; Thermodynamics; Thromboembolism; Thrombosis; Thrombus; Venous; Wit; base; biophysical techniques; clinically significant; comparative; computerized; conformational conversion; crosslink; in vivo; inhibitor/antagonist; insight; molecular domain; molecular dynamics; multi-scale modeling; mutant; nanomechanics; network models; new therapeutic target; novel; novel strategies; optical traps; polymerization; prevent; reconstruction; response; screening; simulation; single molecule; therapeutic target; thrombolysis; two-dimensional; wound

DESCRIPTION (provided by applicant): A new field of biomedical research, biomechanics of hemostasis and thrombosis, has been quickly developing over the past few years. The mechanical properties of fibrin are naturally variable and largely determine whether clots stanch bleeding, or lead to thrombosis or hemorrhage, and this makes them a desirable therapeutic target. In this application, fibrin mechanics will be studied with respect to structural changes during physiologically relevant fibrin deformations at increasing levels of complexity, including individual molecules, fibrin oligomers, and whole fibrin clots as well as ex vivo thrombi. The structural basis of the viscoelastic properties of fibrin is going to be examined using a uniquely broad, integrated approach based on state-of-the- art biophysical techniques, such as single-molecule optical trap-based force spectroscopy, wide angle X-ray scattering, Fourier Transform infrared spectroscopy, high-resolution rheometry, atomic force microscopy, confocal and electron microscopy, combined with computational molecular dynamics simulations and multiscale modeling. In Specific Aim 1, the structural transitions in fibrin at the molecular level induced by mechanical force will be studied. Understanding of the unfolding of the coiled-coils, αC regions, and γ-nodules will define the molecular changes that occur in vivo as a result of blood flow, clot retraction, and wound stretching. The α-helix to β-sheet transition in the coiled-coils is an important mechanism of fibrin mechanics and potentially tunable for clinical purposes. Straightening of the αC polymers and unfolding of the ?-nodules also play major roles in fibrin mechanical properties. In Specific Aim 2, nanomechanics of the A:a knob-hole bonds that hold fibrin together will be studied at the single-molecule level. Preliminary data show that at the A:a bonds exhibit counterintuitive "catch" bond behavior, meaning that the strength of the bond increases with increasing force. This novel finding is a basis for further in depth studies because of its general importance for the field of biomolecular interactions and potential physiological significance. Using a new approach, Binding- Unbinding Correlation Spectroscopy, that we developed we will extensively characterize the two-dimensional kinetics and thermodynamics of formation and dissociation of single A:a bonds. In Specific Aim 3, mechanical properties of clinically significant clots and thrombi will be studied, with a logical progression from the molecular and microscopic levels to increasingly complex macroscopic structures formed in vivo. Screening of chemicals and structural modifications that potentially stabilize or destabilize fibrin molecular domains will be performed to reveal potential modulators of fibrin mechanical properties for therapeutic purposes. These studies would advance the field of hemostasis and thrombosis by leading to new structure- and mechanics-based approaches to prevent and treat bleeding and thrombosis.

描述(申请人提供)：生物医学研究的一个新领域，止血和血栓形成的生物力学，在过去的几年里发展迅速。纤维蛋白的机械性质自然是可变的，在很大程度上决定了凝块是止血，还是导致血栓形成或出血，这使它们成为理想的治疗靶点。在这项应用中，将研究与生理相关的纤维蛋白变形过程中不断增加的复杂性的结构变化，包括单个分子、纤维蛋白低聚体、整个纤维蛋白凝块以及体外血栓。纤维蛋白粘弹性性质的结构基础将通过一种独特的、广泛的、综合的方法来研究，该方法基于最先进的生物物理技术，如单分子光学陷阱力谱、广角X射线散射、傅立叶变换红外光谱、高分辨率流变仪、原子力显微镜、共聚焦和电子显微镜，并结合计算分子动力学模拟和多尺度模拟。在特定目标1中，纤维蛋白在分子水平上的结构转变 将研究由机械力引起的。了解盘绕线圈、αC区和γ结节的展开将定义由于血流、凝块回缩和伤口拉伸而在体内发生的分子变化。卷曲线圈中的α-螺旋到β-折叠的转变是纤维蛋白力学的一个重要机制，并有可能用于临床。αC聚合物的拉直和β-结节的展开也对纤维蛋白的机械性能起着重要作用。在具体目标2中，将在单分子水平上研究将纤维蛋白结合在一起的A：A旋钮孔键的纳米力学。初步数据显示，在A：A 债券表现出与直觉相反的“接住”债券行为，这意味着债券的强度随着力量的增加而增加。这一新发现是进一步深入研究的基础，因为 它对于生物分子相互作用领域的普遍重要性和潜在的生理意义。使用我们开发的一种新的方法--结合-解结合相关光谱，我们将广泛地表征单个A：A键的形成和解离的二维动力学和热力学。在具体目标3中，将研究具有临床意义的血栓和血栓的机械特性，从分子和微观水平到体内形成的日益复杂的宏观结构的逻辑发展。筛选可能稳定或破坏稳定的化学品和结构修饰 纤维蛋白分子结构域将被用于揭示潜在的用于治疗目的的纤维蛋白机械性质的调节剂。这些研究将通过导致基于结构和力学的新方法来预防和治疗出血和血栓形成，从而推动止血和血栓形成领域的发展。