Fibrin(ogen) Structure and Interactions

描述（由申请方提供）：纤维蛋白原（340 kDa）是一种多功能血浆蛋白，活化后自发聚合形成纤维蛋白凝胶。纤维蛋白酶可防止血管损伤时的失血，并随后作为临时基质，在伤口愈合和其他生理和病理过程中，各种细胞类型在其上粘附、迁移和增殖。纤维蛋白原以可控方式粘附和降解的能力以及粘附于不同细胞的能力使其成为理想的生物粘附剂（纤维蛋白密封剂）已经越来越多地用于许多外科应用中，用于止血、组织粘合、生物活性物质的递送，更好地了解纤维蛋白的机制-纤维蛋白封闭剂的依赖性过程和更有效的应用需要对这种复杂分子的结构和相互作用的全面了解。最近的研究建立了约三分之二分子的高分辨率结构。本申请的第一个目的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α C-结构域与纤溶酶原、tPA和apo（a）以高亲和力相互作用，表明它们参与纤维蛋白溶解和动脉粥样硬化形成。第二个目的是描述这些相互作用的特点，并澄清它们在调节这些过程中的作用。其他纤维蛋白（原）区域、γ-模块和β-N-结构域与白细胞和内皮细胞上的受体的相互作用显示出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互动的机制。这些目标将通过有限的蛋白水解和重组技术制备各种纤维蛋白（原）结构域及其组合，并通过生物化学和生物物理方法研究其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）依赖性过程的能力产生影响。它们还将有助于开发具有所需性能的改进的纤维蛋白密封剂。

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.