Structural Identification and Functional Consequences of Different Amyloid Strains in Alzheimer's Disease

阿尔茨海默病与衰老过程中淀粉样蛋白在大脑中的沉积有关。以来 淀粉样蛋白形成与AD之间的相关性最初是建立的，人们已经认识到存在 许多亚型和疾病的形式。例如，淀粉样β蛋白（Aβ）的积累 是阿尔茨海默病（AD）的标志。然而，有一个穷人 目前还不清楚淀粉样蛋白形成的原因，也不知道是否有独特的结构基序， 促进导致痴呆症的独特病理后果。这份提案的重点是填补这一 知识的严重空白。因此，该提议的总体假设是， 具有不同亚型的淀粉样蛋白具有确定其位置和病理的不同结构。解决 这个假设我们提出了两个具体目标。 首先，我们计划从迟发性AD和早发性AD的死后脑组织的不同亚型中分离淀粉样蛋白。 家族性AD我们计划比较五种不同的淀粉样斑块亚型：典型AD，非典型AD，棉 羊毛，早发性AD（EOAD）和极早发性AD（VEOAD）。最后两个子类型与 家族性AD突变可获得关于年龄和性别、发病年龄和持续时间的临床信息。 疾病、病程和症状、药物和ApoE基因型。在EOAD和VEOAD中 对30例患者进行APP、PSEN 1、PSEN 2和tau基因检测。在大多数情况下，CSF中的生物标志物 和神经影像学检查结果。分离的淀粉样蛋白将作为种子，使纤维生长成核， 体外研究。原纤维的结构和多态性将通过互补结构分析来评估。 方法包括固态NMR光谱、傅里叶变换红外光谱、透射光谱。 电子显微镜和原子力显微镜。 使用从AD的五种不同亚型中分离的淀粉样蛋白，我们将评估其生物功能。 使用三种方法分析不同菌株的结果。首先，我们将评估 炎症反应和细胞毒性，由于不同的原纤维形式使用小胶质细胞培养。二是 将决定淀粉样蛋白菌株对促进神经炎症的影响。第三，我们将确定 淀粉样蛋白菌株对大鼠脑内装配和增殖的影响。 总体目标是将不同淀粉样蛋白亚型的病理（生物功能后果） 细胞培养，大鼠大脑和人脑之间的联系，并将这些病理与特定的结构 与来自每种亚型的分离的淀粉样蛋白相关的Aβ原纤维的特征。

Alzheimer's disease is associated with the deposition of amyloid in the brain during aging. Since the correlation between amyloid formation and AD was originally made, it has been recognized that there are many subtypes and forms that the disease can take. For example, accumulation of the amyloid β-protein (Aβ) in the brain parenchyma is the hallmark of Alzheimer's disease (AD). Nevertheless, there is a poor understanding as to why amyloid forms, and it is not known whether there are unique structural motifs that promote the distinct pathological consequences leading to dementia. The focus of this proposal is to fill this critical void in knowledge. Accordingly, the overall hypothesis of this proposal is that the Aβ peptides forming amyloid with distinct subtypes have distinct structures that determine their location and pathology. To address this hypothesis we propose two specific aims. First, we plan to isolate amyloid from different subtypes of post mortem brain tissue of late-onset AD and early- onset familial AD. We plan to compare five different amyloid plaque subtypes: typical AD, atypical AD, cotton wool, early-onset AD (EOAD) and very early-onset AD (VEOAD). The last two subtypes are associated with familial AD mutations. Clinical information is available concerning age and gender, age of onset and duration of disease, course and symptoms of the disease, medication and ApoE genotype. In the EOAD and VEOAD cases genetic testing was performed for APP, PSEN 1, PSEN2 and tau. For most cases, biomarkers in CSF and neuroimaging results are available. The isolated amyloid will serve as seeds to nucleate fibril growth for in vitro studies. The structure and polymorphism of the fibrils will be assessed by complementary structural approaches including solid-state NMR spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and atomic force microscopy. Using the amyloid isolated from the five different subtypes of AD, we will assess the biofunctional consequences of the different strains using three approaches. First, we will assess the differences in the inflammatory response and cell toxicity due to different fibril forms using microglial cell cultures. Second, we will determine the influence of amyloid strains on promoting neuroinflammation. Third, we will determine the influence of amyloid strains on assembly and propagation in rat brain. The overall objective is to correlate pathologies (biofunctional consequences) of different amyloid subtypes between cell culture, rat brain and human brain, and to relate these pathologies with specific structural characteristics of the Aβ fibrils that are associated with the isolated amyloid from each subtype.