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: 7729670
• 负责人: JOHN W WEISEL
• 金额: $ 39.1万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-20 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7729670
• 关键词: Appearance; Applications Grants; Atomic Force Microscopy; Behavior; Beryllium; Biochemical; Biocompatible Materials; Biological; Biomechanics; Biomedical Research; Biopolymers; Blood Clot; Blood Platelets; Blood coagulation; Blood flow; Bundling; Caliber; Characteristics; Clinical; Coagulation Process; Coronary artery; Custom; DNA Sequence Rearrangement; Diagnosis; Disease; Elasticity; Engineering; Event; Factor XIII; Fiber; Fibrin; Fibrinogen; Fluorescence Microscopy; Hemorrhage; Hemostatic function; Impaired wound healing; Individual; Lead; Measurement; Measures; Mechanical Stress; Mechanics; Methods; Microscopic; Modeling; Molecular; Molecular Analysis; Molecular Structure; Motion; Myocardial Infarction; Nature; Patients; Pattern; Pharmacia brand of estropipate; Physiological; Plasma; Polymers; Property; Prophylactic treatment; Proteins; Recombinants; Relative (related person); Research; Roentgen Rays; Rupture; Scanning Probe Microscopes; Scanning Transmission Electron Microscopy Procedures; Shapes; Side; Spectroscopy, Fourier Transform Infrared; Stress; Stretching; Stroke; Structure; Surface; System; Techniques; Testing; Thrombin; Thromboembolism; Thrombosis; Thrombus; Time; Vacuum; Variant; Wound Healing; X ray diffraction analysis; X-Ray Diffraction; base; clinically significant; flexibility; in vivo; laser tweezer; magnetic field; mechanical behavior; molecular domain; multi-scale modeling; nano; nanoscale; network models; protein function; public health relevance; research study; single molecule; theories

DESCRIPTION (provided by applicant): Although we know a great deal about the structure and many aspects of the functions of fibrin(ogen), we still know very little about the microscopic and molecular structural origins of the fibrin clot's mechanical properties. Since blood clotting in vivo is essentially a mechanical task, it is important to determine how clots and thrombi respond to mechanical stresses imposed by highly dynamic conditions, such as blood flow, stretching a vessel wall and wounds, etc. In the research proposed in this application, the structural basis of the elastic and viscous properties of fibrin biopolymers is going to be examined using an integrated approach, which includes different levels of analysis, the molecular level, individual fibers, fiber network, and the whole clot, and the determination of relationships between these different levels of structure. Specific Aim 1: At the nano scale, the micromechanics of fibrin(ogen) will be examined by forced unfolding of its molecular domains during pulling on engineered oligomeric constructs by single-molecule atomic force microscopy, and observing the structural transitions by wide angle X-ray diffraction or Fourier Transform infrared spectroscopy while stretching of fibrin clots. Specific Aim 2: At the microscopic scale, the mechanical properties of fibers will be studied by bending and stretching of individual fibers in different clots by atomic force microscopy or optical tweezers, and investigating potential elongation of molecules and molecular packing by means of the small angle X-ray diffraction pattern during stretching of magnetically oriented clots. Structural changes in fiber network rearrangement, such as alignment and bundling of fibers, with clot deformation will be examined by scanning and transmission electron microscopy. Specific Aim 3: At the macro level, the viscoelastic properties of a variety of whole clots and thrombi extracted from patients' coronary arteries will be measured using rotational and extensional rheometry and correlated with parameters quantifying clot and thrombi structure. To build a general theory of the structural origin of clot mechanics, we will develop constitutive models that take advantage of the quantitative information derived from experiments at all the structural levels. In biological terms, fibrin(ogen) may represent one of the first clear examples of the physiological function of forced protein unfolding. On the clinical side, understanding mechanisms of fibrin deformation would explain and predict clot behavior in different physiological or pathophysiological conditions related to hemostasis, thrombosis, and wound healing and may lead to new methods of prophylaxis, diagnosis, or treatment. The proposal represents a new and promising field of biomedical research, namely biomechanics of hemostasis and thrombosis. PUBLIC HEALTH RELEVANCE: The focus of the research proposed in this grant application will be on the characteristics of fibrin(ogen) molecules, fibers, and networks that give rise to blood clot mechanical properties and the determination of relationships between these different levels of structure, using a variety of biophysical techniques. The results of these studies have clinical significance since clots with low elasticity and high plasticity tend to be associated with bleeding, while very stiff clots have been associated with thrombosis and thromboembolism, which cause heart attacks and strokes. In biological terms, fibrin(ogen) may represent one of the first clear examples of the physiological function of protein unfolding. More generally, this research involves the determination of relationships between molecular structure and the mechanical properties of a remarkable biological material, the blood clot.

描述（由申请人提供）：尽管我们对纤维蛋白（OGEN）功能的结构和许多方面了解很多，但我们仍然对纤维蛋白凝块机械性能的显微镜和分子结构起源知之甚少。 Since blood clotting in vivo is essentially a mechanical task, it is important to determine how clots and thrombi respond to mechanical stresses imposed by highly dynamic conditions, such as blood flow, stretching a vessel wall and wounds, etc. In the research proposed in this application, the structural basis of the elastic and viscous properties of fibrin biopolymers is going to be examined using an integrated approach, which includes different levels of analysis, the molecular level, individual纤维，光纤网络和整个凝块，以及这些不同结构级别之间的关系。具体目的1：在纳米量表上，将通过在通过单分子原子力显微镜来启动工程的寡聚构建体时强迫其分子结构域来检查纤维蛋白（OGE）的微力学，并通过单分子原子力显微镜以及通过广角X射线射线衍射或傅立叶衍射型fromstrared Expspercophy观察结构过渡。具体目标2：在显微镜尺度上，将通过原子力显微镜或光学镊子弯曲和拉伸各个凝块中的单个纤维来研究纤维的机械性能，并通过在小角度X射线差异模式的含量中研究分子的潜在伸长和分子包装的潜在伸长。将通过扫描和透射电子显微镜检查纤维网络重排的结构变化，例如纤维的比对和捆绑纤维的结构变化。特定目标3：在宏观水平上，将使用旋转和延伸的流变仪测量各种从患者冠状动脉中提取的各种整个凝块和血栓的粘弹性特性，并与量化凝块和血栓结构的参数相关。为了构建凝块力学的结构起源的一般理论，我们将开发构成模型，以利用从所有结构层面上实验得出的定量信息。用生物学术语，纤维蛋白（OGEN）可能代表强迫蛋白展开的生理功能的第一个明确例子之一。在临床方面，了解纤维蛋白变形的机制将解释和预测与止血，血栓形成和伤口愈合有关的不同生理或病理生理状况中的血凝块行为，并可能导致预防，诊断或治疗的新方法。该提案代表了一个新的且有希望的生物医学研究领域，即止血和血栓形成的生物力学。公共卫生相关性：本赠款应用中提出的研究的重点将放在纤维蛋白（OGEN）分子，纤维和网络的特征上，这些分子，纤维和网络会引起血凝块机械性能，并使用各种生物物理技术来确定这些不同水平的结构之间的关系。这些研究的结果具有临床意义，因为弹性低和高可塑性的凝块往往与出血有关，而非常僵硬的凝块与血栓形成和血栓栓塞有关，这会导致心脏病发作和中风。用生物学术语，纤维蛋白（OGEN）可能代表了蛋白质展开的生理功能的第一个明确例子之一。更普遍地，这项研究涉及确定分子结构与非凡生物材料的机械性能之间的关系。