Fibrin(ogen) Structure and Interactions

描述(申请人提供)：纤维蛋白原(340 KDa)是一种多功能血浆蛋白，激活后会自发聚合形成纤维蛋白凝胶。纤维蛋白可防止血管损伤时失血，随后作为一种临时基质，在伤口愈合和其他生理和病理过程中各种类型的细胞在其上黏附、迁移和增殖。纤维蛋白原能够以可控的方式聚合和降解，并附着在不同的细胞上，使其成为一种理想的生物粘合剂(纤维蛋白密封剂)，已越来越多地被用于止血、粘合组织、输送生物活性物质等外科应用。要更好地了解纤维蛋白依赖过程的潜在机制和更有效地应用纤维蛋白密封剂，需要全面了解这种复杂分子的结构和相互作用。最近的研究确定了大约三分之二的分子的高分辨率结构。这项应用的第一个目标是完成剩余区域的高分辨率结构，并进一步阐明纤维蛋白原转化为纤维蛋白时的构象变化。我们最近发现，纤维蛋白原αC结构域与纤溶酶原、tPA和apo(A)具有高亲和力，提示它们参与了纤溶和动脉粥样硬化的形成。第二个目标是描述这些相互作用的特点，并阐明它们在调节这些过程中的作用。其他纤维蛋白(原)区域，伽马模块和Betan结构域，与白细胞和内皮细胞上的受体相互作用，被证明刺激炎症和血管生成。第三和第四个目标侧重于进一步建立这些相互作用的机制。这些目标将通过有限的蛋白分解和重组技术制备各种纤维蛋白(原)结构域及其组合，并通过生化和生物物理方法研究它们的结构和相互作用来实现。这些研究将产生基础知识，这些知识将对理解和控制上述纤维蛋白(原)依赖过程的能力产生影响。它们还将有助于开发具有理想性能的改进型纤维蛋白密封剂。

DESCRIPTION (provided by applicant): Fibrinogen (340 kDa) is a multifunctional plasma protein that after activation spontaneously polymerizes to form a fibrin gel. Fibrin prevents the loss of blood upon vascular injury and serves subsequently as a provisional matrix on which various cell types adhere, migrate and proliferate during wound healing and other physiological and pathological processes. The ability of fibrinogen to polymerize and degrade in a controllable fashion and to adhere to different cells makes it an ideal bioadhesive (fibrin sealant) that has been used increasingly in numerous surgical application for arrest of bleeding, gluing of tissues, delivery of bioactive substances, etc. Better understanding of the mechanisms underlying fibrin-dependent processes and more effective application of fibrin sealant require comprehensive knowledge of the structure and interactions of this complex molecule. Recent studies established a high resolution structure of about two-thirds of the molecule. The first aim of this application is to complete the high-resolution structure of the remaining regions and to further clarify conformational changes upon conversion of fibrinogen to fibrin. Our recent discoveries that fibrinogen alphaC-domains interact with high affinity with plasminogen, tPA and apo(a) suggest their involvement in fibrinolysis and atherogenesis. The second aim is to characterize these interactions and to clarify their role in regulation of these processes. Interactions of the other fibrin(ogen) regions, gamma-modules and the betaN-domains, with receptors on leukocytes and endothelial cells was shown to stimulate inflammation and angiogenesis. The third and fourth aims focus on further establishing the mechanisms of these interactions. These aims will be accomplished by preparation of various fibrin(ogen) domains and combinations thereof by limited proteolysis and recombinant techniques, and studying their structures and interactions by biochemical and biophysical methods. These studies will generate basic knowledge that will have an impact on the understanding of and ability to control the above mentioned fibrin(ogen)-dependent processes. They will also contribute to the development of improved fibrin sealants with desirable properties.