CD14 and TLRs in Abeta-Induced Microglial Signaling

描述（由申请人提供）：本研究计划旨在阐明小胶质细胞识别纤维状β淀粉样蛋白（fAbeta）诱导促炎反应的机制。这是至关重要的，因为炎症已被证明与阿尔茨海默病（AD）的疾病病理密切相关。小胶质细胞与抗体斑块的相互作用导致促炎信号级联和神经毒性分泌产物的分泌。先前的研究已经证明了小胶质细胞表面上的多组分受体复合物，其介导fAb的结合和随后的细胞内信号传导途径的激活，导致促炎反应和吞噬作用的诱导。此外，在单核细胞和嗜中性粒细胞表面发现的蛋白质CD14作为微生物检测受体激活免疫细胞以消除病原体，与fAb结合有关。我们假设CD14作为fAb细胞表面受体复合物的成员结合fAbeta并引发促炎反应。该提案旨在确定fAb诱导的细胞内效应物信号传导是否需要CD14，以及它是否与受体成分相关。它还试图确定产生炎症反应的CD14下游的信号级联。为了实现这些目标，她将使用多种方法的组合，包括功能阻断抗体和RNAi载体来抑制蛋白质功能，免疫沉淀和FRET来检测fAb受体复合物分子的缔合，Western印迹分析，实时PCR和ELISA来检测信号蛋白，炎症分子和Ab肽的表达水平，以及CD14，TLR4，TLR2和MyD88缺陷的小鼠，以及模拟AD以检查CD 14在AD小鼠模型中通过fAb激活小胶质细胞和斑块发展中的重要性的那些。该申请提出更好地理解大脑的免疫细胞工作以触发对阿尔茨海默病大脑中形成的纤维状Abeta沉积物的免疫反应的方式。它将为开发新的治疗方法和更好地理解这些过程提供信息。

DESCRIPTION (provided by applicant): This research proposal is designed to elucidate the mechanisms by which microglia recognize fibrillar beta amyloid (fAbeta) to induce a pro-inflammatory response. This is critical as inflammation has been shown to be intimately involved in the disease pathology of Alzheimer's disease (AD). Interactions of microglia with Ab plaques results in pro-inflammatory signaling cascades and the secretion of neurotoxic secretory products. Previous studies have demonstrated a multi-component receptor complex on the surface of microglia that that mediates the binding of fAb and subsequent activation of intracellular signaling pathways leading to a pro-inflammatory response and an induction of phagocytosis. Moreover, CD14, a protein found on the surface of monocytes and neutrophils that serves as a microbe-detecting receptor to activates immune cells to eliminate pathogens, has been implicated in binding fAb. We hypothesize that CD14 acts as a member of the fAb cell surface receptor complex to bind fAbeta and elicit a pro-inflammatory response. This proposal seeks to determine whether CD14 is required for fAb-induced signaling to intracellular effectors, and whether it associates with the receptor components to do so. It also seeks to identify the signaling cascades downstream of CD14 that produce an inflammatory response. To achieve these goals, she will use a combination of approaches, including function blocking antibodies and RNAi vectors to inhibit protein function, immunoprecipitation and FRET to detect association of fAb receptor complex molecules, Western blot analysis, real-time PCR, and ELISA to detect expression levels of signaling proteins, inflammatory molecules, and Ab peptides, and mice deficient in CD14, TLR4, TLR2, and MyD88, as well as those that model AD to examine the importance of CD14 in microglial activation by fAb and plaque development in a mouse model of AD. This application proposes to better understand the ways in which the immune cells of the brain work to trigger an immune response to the fibrillar Abeta deposits that form in the Alzheimer's disease brain. It will inform development of new therapeutic approaches and a better understanding these processes.