FIBRINOGEN STRUCTURE IN HEMOSTASIS AND ATHEROSCLEROSIS

止血和动脉粥样硬化中的纤维蛋白原结构

• 批准号: 2223913
• 负责人: JAY L DEGEN
• 金额: $ 16.38万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2223913
• 关键词: apolipoproteins; atherosclerosis; cellular pathology; disease /disorder model; fibrin; fibrinogen; gene expression; gene mutation; gene targeting; genetic promoter element; genetic regulation; genetically modified animals; hemostasis; laboratory mouse; messenger RNA; model design /development; molecular pathology; platelet aggregation; polymerization; protein biosynthesis; protein degradation; protein structure function; recombinant proteins

A detailed understanding of the fibrinogen molecule has been a long- standing goal of cardiovascular research because of the physiological role of this key coagulation factor in the control of blood loss and wound healing, and potential pathologic role of the protein in a variety of common diseases, including atherosclerosis, myocardial infarction, and stroke. The long-term aims of this research program are to dissect and characterize the functional elements of fibrinogen and to define the consequences of selected alterations in fibrinogen on hemostasis, wound healing, and disease. Fibrinogen gene-targeted transgenic mice provide a unique experimental system where the endogenous fibrinogen genes can be freely manipulated in vivo and large (i.e., clottable) quantities of recombinant fibrinogen can be generated for biochemical studies. This study will employ currently available transgenic mice lacking fibrinogen (Aalpha chain) and the cloned and sequenced murine Aalpha chain gene to specifically: 1) explore the function of the carboxy-terminal domains of the Aalpha chain, including a) the "carboxy-terminal extension" (alphaC domain) that constitutes ~2/3 of the Aalpha chain, and b) the newly- discovered (and highly-conserved) alphaE domain ("Extended) that is joined to the alphaC domain in a fraction of plasma fibrinogen by alternative splicing; and 2) test the long-standing hypothesis that fibrin(ogen) deposition is a critical factor in the development of atherosclerotic lesions. Under Specific Aim 1, the biochemistry of plasma fibrinogen, clotting function, risk of spontaneous hemorrhagic events, and wound healing will be characterized in transgenic mice in which the endogenous Aalpha products are replaced with forms of the Aalpha chain: i) lacking the alphaC domain, ii) carrying the normal alpha C domain, but with no fraction carrying the alphaE domain, and iii) uniformly carrying the alphaE domain. One working hypothesis to be tested in this study is that alphaE domain promotes the branching of fibrin polymers; therefore, clots formed from fibrinogen that uniformly carries the alphaE domain may be remarkably branched. Under Specific Aim 2, the impact of wholesale loss of plasma fibrinogen on the development and progression of atherosclerotic plaques will be defined. This work will provide the first direct experiment data regarding a "casual" role of fibrin(ogen) in the progression of atherosclerosis. The working hypothesis is that the absence of fibrinogen will reduce the local migration and deposition of cells contributing to plaque development, including platelets, macrophages, and endothelial cells that are each known to carry distinct fibrin(ogen) receptors. If this proves to be correct, then these studies could provide a new foundation for the development of therapeutic strategies to prevent and treat this common vascular disease.

对纤维蛋白原分子的详细理解已经是长期的 由于生理学的心血管研究的常规目标 该关键凝血因素在控制失血和 伤口愈合，蛋白质中蛋白质的潜在病理作用 常见疾病，包括动脉粥样硬化，心肌梗塞和 中风。 该研究计划的长期目标是剖析和 表征纤维蛋白原的功能元素，并定义 纤维蛋白原部分止血的后果，伤口 康复和疾病。 纤维蛋白原基因靶向转基因小鼠提供 一个独特的实验系统，内源性纤维蛋白原基因可以 在体内自由操纵，大量（即可凝结）数量 重组纤维蛋白原可用于生化研究。 这 研究将采用目前缺乏纤维蛋白原的当前可用的转基因小鼠 （Aalpha链）和克隆和测序的鼠Aalpha链基因 具体：1）探索羧基末端域的功能 Aalpha链，包括a）“羧基末端扩展”（alphac 构成Aalpha链的〜2/3的域），b）新近 发现（和高度保存的）α域（“扩展）是 通过一小部分血浆纤维蛋白原连接到alphac域 替代剪接； 2）检验以下假设 纤维蛋白（OGEN）沉积是发展的关键因素 动脉粥样硬化病变。 在特定目标1下，生物化学 血浆纤维蛋白原，凝血功能，自发性出血的风险 事件和伤口愈合将在转基因小鼠中表征 内源性Aalpha产物被以这种形式取代 aalpha链：i）缺乏alphac域，ii）携带正常α C域，但没有载有α域的分数，iii） 均匀地携带α域。 一个工作假设是 在这项研究中测试的是，α域促进了 纤维蛋白聚合物；因此，由纤维蛋白原形成的凝块均匀 携带α域可能会明显分支。 在特定目标下 2，血浆纤维蛋白原批发损失对发育的影响 将定义动脉粥样硬化斑块的进展。 这项工作 将提供有关“休闲”角色的第一个直接实验数据 动脉粥样硬化进展中纤维蛋白（OGEN）的含量。 工作 假设是缺乏纤维蛋白原会减少局部 有助于斑块发育的细胞的迁移和沉积， 包括血小板，巨噬细胞和内皮细胞 已知携带不同的纤维蛋白（OGEN）受体。 如果证明是 正确，这些研究可以为 制定预防和治疗这一常见的治疗策略 血管疾病。