Physical Biochemistry and Biology of Amyloid Beta-Protein

描述(申请人提供)：阿尔茨海默病(AD)是一种毁灭性的老年人疾病。两种淀粉样蛋白与阿尔茨海默病有关，即淀粉样蛋白(A？)和tau。最近的证据支持一种假说，即“淀粉样蛋白级联假说”，该假说认为A？寡聚体是阿尔茨海默病的神经致病因子。这项建议的总体目标是了解Aü及其片段的结构生物学，并建立正式的结构-活性关系。从长远来看，我们寻求获得一个原子分辨率确定的最接近的神经毒素的结构，并在这样做，这样做，使开发，第一次，以改善疾病的AD治疗。将采用多学科战略，采用互补的实验和计算方法。这一策略在过去得到了非常成功的应用，为阿伯系统提供了新的见解。我们提出了三个具体的目标，从系统和逻辑上取得进展，从Aü及其低聚体组件的体外生物物理研究(目标1)，到体外和体内对选定的此类组件的生物活性的研究(目标2)，再到确定选定组件对神经元差异基因表达的影响(目标3)。综上所述，这些研究将为后续的治疗化合物开发和临床试验提供理论和实验基础。目的1.确定Aü和tau组装的结构动力学。A.用扫描酪氨酸突变法研究A？寡聚的作用机制。B.确定分子内转角形成的动力学及其对A？组装的影响。C.确定一级结构变化对具有生物学意义和理论意义的多肽的构象和组装动力学的影响。目的2.测定A？集合体的生物学效应。A.确定A？集合体对培养的神经细胞系和原代神经元的细胞毒作用。B.确定Aü组件对果蝇眼睛发育、运动和寿命的影响。目的3.利用生物信息学方法识别和验证AD相关基因，该方法考虑了A？装配结构、神经元类型和神经元衰老。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is a devastating disease of the aged. Two amyloid-forming proteins are associated with AD, the amyloidß-protein (Aß) and tau. Recent evidence supports an hypothesis, the "amyloid cascade hypothesis," that posits that Aß oligomers are the seminal neuropathogenetic agents in AD. The overall goal of this proposal is to understand the structural biology of Aß, and fragments thereof, and to establish formal structure-activity relationships. In the long run, we seek to obtain an atomic-resolution determination of the structure of the proximate neurotoxins formed by Aß, and in doing so, enable the development, for the first time, of disease-modifying AD treatments. A multidisciplinary strategy, employing complementary experimental and computational approaches, will be employed. This strategy has been used very successfully in the past, providing novel insights into the Aß system. Three specific aims are proposed that systematically and logically progress from in vitro biophysical studies of Aß and its oligomeric assemblies (Aim 1), to in vitro and in vivo studies of the biological activity of selected such assemblies (Aim 2), to determination of the effects of selected assemblies on differential gene expression in neurons (Aim 3). Taken together, these studies will provide the theoretical and experimental foundation for subsequent therapeutic compound development and clinical testing in humans. Aim 1. To determine the structural dynamics of Aß and tau assembly. a. To use scanning Tyr mutagenesis to elucidate mechanisms of Aß oligomerization. b. To determine the dynamics of intramolecular turn formation and its effects on Aß assembly. c. To determine the effects of primary structure changes on the conformations and assembly dynamics of biologically relevant and theoretically important Aß peptides. Aim 2. To determine the biological effects of Aß assemblies. a. To determine the cytotoxic effects of Aß assemblies on cultured neuronal cell lines and primary neurons. b. To determine the effects of Aß assemblies on Drosophila eye development, locomotion, and longevity. Aim 3. To identify and validate AD-relevant genes using a bioinformatics approach that considers Aß assembly structure, neuron type, and neuron senescence.