SIMULATION OF BIOMOLECULES

增加的血小板膜流动性(PMF)，通过测量 荧光各向异性的降低 标记膜中的1，6-二苯基-1，3，5-己三烯(DPH)，鉴定出 阿尔茨海默病(AD)患者亚组，他们有明显的 临床特点。这种表型似乎是一种稳定的家族性 在患者家属中垂直传播的特征 阿尔茨海默氏症。这些家系数据的分离分析 指示PMF的增加是由继承单个 控制这个变异的至少80%的主要基因座 膜表型。因此，PMF轨迹似乎是一个重要的 阿尔茨海默病临床异质性的常见遗传来源 疾病。在细胞水平上，来自超微结构和 生化研究表明，PMF的增加是由于 异常内膜堆积，似光滑 可能是功能异常的内质网。在.期间 要求奖励期限，我们建议前瞻性评估增加 PMF作为AD的风险因素，以进一步定义细胞和 增加PMF的分子基础，并利用这一信息 直接假说驱动的死后脑组织研究旨在 阐明阿尔茨海默病的病理生理机制。我们的具体目标是：1. 确定PMF增加是否可以预测原发性高血压的发生率 330名儿童一级亲属的高危队列中的痴呆症 在入院时认知功能完好无损的AD患者 这项正在进行的纵向研究。作为这项研究的一部分，转变为 将建立细胞系，为今后的研究提供便利 推测阿尔茨海默病的遗传危险因素。2.确定PMF是否 基因座位于长臂21号染色体上，在该染色体上有几个基因 与阿尔茨海默病生物学相关的，以前都局限于，或者接近于 据报道，19号染色体区域与AD易感性有关。3. 确定点突变的频率和分布 阿尔茨海默病患者APP基因的跨膜区 死亡时没有阿尔茨海默病的患者。4.确定 直接判断PMF结果的增加是否会导致 内膜，选择性地增加了内膜的流动性 血小板膜，或两者，使用分离的内部制剂 和体外血小板膜。如果，正如我们初步建议的那样 研究表明，这两种变化都是观察到的，膜成分 导致内部流动性增加的变化 还将对膜进行调查。5.确定分布 可溶性和膜结合形式的b-淀粉样前体蛋白 (APP)，并调查是否有加工或 这种糖基化的膜蛋白在AD中的分布发生了变化 PMF增高的患者。6.审视……的关系 生前PMF对老年斑块密度的测定 和脑内的神经原纤维缠结在死于 已确认AD。

Increased platelet membrane fluidity (PMF), as measured by a decrease in the fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPh) in labeled membranes, identifies a subgroup of patients with Alzheimer's disease (AD) who have distinct clinical features. This phenotype appears to be a stable, familial trait that is vertically transmitted in families of patients with Alzheimer's disease. Segregation analysis of data from these families indicates that increased PMF results from the inheritance of a single major locus that controls at least 80% of the variance in this membrane phenotype. Thus, the PMF locus appears to be an important and common genetic source of clinical heterogeneity in Alzheimer's disease. At the cellular level, evidence from ultrastructural and biochemical studies suggests that increased PMF results from an accumulation of abnormal internal membranes resembling smooth endoplasmic reticulum that may be functionally abnormal. During the requested award period, we propose to prospectively evaluate increased PMF as a risk factor for AD, to further define the cellular and molecular basis for increased PMF, and to use this information to direct hypothesis-driven studies of post-mortem brain tissue aimed at elucidating the pathophysiology of AD. Our specific aims are to: 1. Determine whether increased PMF predicts the incidence of primary dementia in a high-risk cohort of 330 first-degree relatives of patients with AD who were cognitively intact at the time of entry into this ongoing longitudinal study. As part of this study, transformed cell lines will be established to facilitate future studies of putative genetic risk factors for AD. 2. Determine whether the PMF locus is located on the long arm chromosome 21, where several genes related to the biology of AD have been previously localized, or near a region of chromosome 19 reported to confer vulnerability to AD. 3. Determine the frequency and distribution of point mutations across the transmembrane region of the APP gene in patients with confirmed AD and patients who did not have AD at the time of death. 4. Determine directly whether increased PMF results form an accumulation of internal membranes, a selective increase in the fluidity of internal platelet membranes, or both, using isolated preparations of internal and external platelet membranes. If, as suggested by our preliminary studies, both alterations are observed, the membrane compositional changes responsible for the increased fluidity of the internal membranes will also be investigated. 5. Determine the distribution of the soluble and membrane-bound forms of b-amyloid precursor protein (APP) in platelets, and investigate whether the processing or distribution of this glycosylated membrane protein is altered in AD patients with increased PMF. 6. Examine the relationship of antemortem determinations of PMF to the densities of senile plaques and neurofibrillary tangles in the brains of patients who died with confirmed AD.