Role of Fibrinogen in Alzheimer's Disease

描述（由申请人提供）：阿尔茨海默病（AD）是一种神经退行性疾病，会导致严重的认知能力下降并最终死亡。目前没有有效的治疗或预防措施，该病的发病率和流行率都在增加。迫切需要新的见解和易于处理的治疗靶点。遗传证据表明，AD的一个主要原因是淀粉样蛋白(a)肽的产生。A -肽可以寡聚并以细胞外斑块的形式沉积在大脑和血管中，但其导致神经元死亡的机制尚不清楚。越来越多的证据表明血管在AD中的作用：患者患有脑灌注不足，脑血管系统受损，存在异常止血。因此，循环缺陷可能在该病的发病机制中起重要作用。我们已经证明了AD小鼠血脑屏障（BBB）通透性和神经血管损伤的增加，并且我们发现纤维蛋白（原）沉积增强了这些过程。我们还发现A与纤维蛋白原结合，对纤维蛋白凝块形成有显著影响。在A¿存在下形成的凝块具有异常结构，并且抗纤溶酶降解。因此，在A¿存在的情况下，形成的任何纤维蛋白沉积都将更加持久，并将加剧血脑屏障损伤、神经炎症和神经元死亡。与已知的AD和ApoE基因型之间的遗传相互作用一致，我们也证明了ApoE影响纤维蛋白原和A¿之间的相互作用，并且同种异构体对人脑纤维蛋白原沉积有不同的影响。为了进一步研究A¿在纤维蛋白凝块形成中的作用，我们将结合体外和体内技术分析和表征A¿与纤维蛋白原的相互作用。各种载脂蛋白e亚型在这一过程中的作用也将被检查。最后，我们将研究在缺乏A¿的情况下纤维蛋白原沉积对大脑的影响，以推断纤维蛋白（原）对ad相关病理的具体贡献。所提出的实验将确定纤维蛋白（原）在AD中的作用，并可能导致预防或延缓疾病进展的新治疗策略。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is a neurodegenerative disorder that leads to profound cognitive decline and eventually death. There are no effective treatments or preventative measures available, and the incidence and prevalence of the disease are increasing. New insights and tractable therapeutic targets are sorely needed. Genetic evidence indicates that a major cause of AD is the production of the ¿-amyloid (A¿) peptide. The A¿ peptide can oligomerize and be deposited as extracellular plaques in the brain and blood vessels, but the mechanism of how it leads to neuronal death is not known. There is increasing evidence of a vascular contribution in AD: patients suffer from brain hypoperfusion, the cerebral vasculature is damaged, and abnormal hemostasis is present. Circulatory deficiencies could therefore play an important role in the pathogenesis of this disease. We have demonstrated an increase in blood brain barrier (BBB) permeability and neurovascular damage in AD mice, and we showed that fibrin(ogen) deposition potentiates these processes. We have also found that A binds to fibrinogen and has a dramatic effect on fibrin clot formation. Clots formed in the presence of A¿ have an abnormal structure and are resistant to degradation by fibrinolytic enzymes. Therefore, in the presence of A¿, any fibrin deposits formed would be more persistent and would exacerbate BBB damage, neuroinflammation, and neuronal death. In keeping with the known genetic interaction between AD and the ApoE genotype, we have also demonstrated that ApoE affects the interaction between fibrinogen and A¿ and the isoforms differentially influence fibrinogen deposition in the human brain. To further study the role of A¿ in fibrin clot formation, we will combine in vitro and in vivo techniques to analyze and characterize the interaction between A¿ and fibrinogen. The role of the various ApoE isoforms in this process will also be examined. Finally, we will examine the effects of fibrinogen deposition on the brain in the absence of A¿ to deduce the specific contribution of fibrin(ogen) to AD-related pathologies. The proposed experiments will define the role of fibrin(ogen) in AD and could lead to new therapeutic strategies for preventing or retarding progression of the disease.