Functional Interaction of Amyloid-b Protein with Glial Toll-Like Receptors

描述（由申请人提供）：阿尔茨海默病（AD）是一种进行性神经退行性疾病，其特征是痴呆增加并最终死亡。阿尔茨海默病突出的病理特征包括严重的神经元丢失，老年斑和弥漫性沉积物中聚集的淀粉样蛋白（A¿）的积累，以及神经原纤维tau缠结。人们普遍认为A¿积累是阿尔茨海默病的主要原因，但仍存在几个核心问题。1)什么A¿结构、聚集状态或物种导致AD？2)人体免疫系统如何识别和应对A¿？重要数据表明，AD大脑中存在对a¿的持续炎症反应，包括在a¿沉积物周围聚集活化的小胶质细胞和细胞因子。令人惊讶的是，并非所有的A¿沉积物都会引起炎症反应，这表明A¿的形态/结构影响了反应。这些结果提出了关于A¿引发炎症反应的机制的几个令人困惑的问题。最近的研究表明，先天免疫系统的toll样受体（TLRs）介导对聚集的a¿的促炎反应，这表明a¿可能具有与微生物大分子相似的结构元件。本提案的工作将利用生物物理和细胞研究来建立小鼠小胶质细胞和星形胶质细胞a¿形态/结构与炎症之间的联系。第一个研究目标是研究影响a¿聚集和结构的各种条件，并确定导致初级小胶质细胞和星形胶质细胞中a¿促炎活性（细胞因子产生）最大的条件。各种生物物理技术将被用来进一步了解A¿结构和神经胶质活化之间的联系。第二个研究目标将利用正常和转基因敲除小鼠来鉴定和表征tlr、共受体和蛋白辅助因子的复合物，这些复合物在胶质细胞表面和细胞内介导A¿的生物活性。进一步了解A¿活性可能有助于解释为什么人类免疫系统在控制AD方面无效，并提供合理的治疗缓解点。该项目在科学和生物医学上的重要性在于它对了解阿尔茨海默病的直接贡献。该项目的另一个同样重要的方面是为研究生和本科生研究人员提供培训机会。拟议的研究是细胞生物学、生物化学、生物物理学、纳米科学和光谱学的融合，将吸引不同群体的学生参与跨学科的研究。这种广泛的科学将促进来自不同部门的学生和教师之间的协作和互动。该项目的主要任务是对阿尔茨海默病产生重大影响。一个同样重要的目标是通过在多个研究领域获得知识，学习和完善实验室技能，以及解释，展示和发表有意义的结果，为学生未来的跨学科研究做好准备。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is a progressive neurodegenerative illness characterized by increasing dementia and ultimately death. Outstanding pathological features of AD include severe neuronal loss, accumulation of aggregated amyloid-¿ protein (A¿) in senile plaques and diffuse deposits, and neurofibrillary tau tangles. It is generally agreed that A¿ accumulation is a primary cause of AD yet several central questions remain. 1) What A¿ structure, aggregation state or species contributes to AD? and 2) How does the human immune system recognize and respond to A¿? Significant data demonstrate a sustained inflammatory response to A¿ in the AD brain which includes clustering of activated microglia and cytokines around A¿ deposits. Surprisingly, not all A¿ deposits provoke an inflammatory response suggesting that A¿ morphology/structure influences the response. These results raise several puzzling questions regarding the mechanism by which A¿ provokes an inflammatory response. Recent work has established that Toll-like receptors (TLRs) of the innate immune system mediate a proinflammatory response to aggregated A¿ suggesting that A¿ may possess structural elements that are similar to microbial macromolecules. The work in this proposal will utilize biophysical and cellular studies to establish a connection between A¿ morphology/structure and inflammation in primary murine microglia and astrocytes. The first research aim will investigate a variety of conditions that influence A¿ aggregation and structure and identify the conditions that result in the greatest A¿ proinflammatory activity (cytokine production) in primary microglia and astrocytes. A variety of biophysical techniques will be used to further understand the connection between A¿ structure and glial activation. The second research aim will utilize normal and transgenic knockout mice to identify and characterize complexes of TLRs, co-receptors, and protein cofactors that mediate A¿ bioactivity at the glial cell surface and inside the cell. Further understanding of A¿ activity may help explain why the human immune system is ineffective at controlling AD and provide a legitimate point of therapeutic mitigation. The scientific and biomedical importance of this project is its direct contribution to the understanding of Alzheimer's disease. The additional and equally important aspect of the project is the training opportunities that it provides for graduate and undergraduate researchers. The proposed research, which is a blend of cell biology, biochemistry, biophysics, nanoscience, and spectroscopy, will attract a diverse group of students to participate in interdisciplinary studies. This broad range of science will promote collaborative work and interactions between students and faculty from different departments. The primary mission of the project is to make a significant impact on Alzheimer's disease. An equally important objective is to prepare students for future interdisciplinary research by gaining knowledge in a multiple research areas, learning and refining laboratory skills, and interpreting, presenting, and publishing meaningful results. PUBLIC HEALTH RELEVANCE: Deaths from Alzheimer's disease (AD) have increased by 45% from 2000 to 2005, while deaths from heart disease, breast cancer, prostate cancer, and stroke have declined during the same time period. AD is projected to reach epic proportions by the middle of the 21st century overwhelming medical resources. The most appropriate way to develop treatments that will prevent or treat AD is to understand the underlying biochemical features of the disease. This proposal will examine molecular mechanisms linking AD and the human immune response potentially leading to therapies that utilize our own immune system to fight AD. Furthermore, the project will incorporate rigorous research training of students at all levels that will ultimately have a positive long-term impact on public health.