BALANCED BIOACTIVITY OF ALZHEIMER BETA AMYLOID PRECURSOR

描述（摘要）：越来越多的证据表明炎症的作用 老年痴呆症数据还表明β-淀粉样蛋白的代谢物 前体蛋白（β-APP）在阿尔茨海默病的病因。我们 先前已经证明分泌形式的β-APP（sAPP）保护 神经元抵抗几种毒性损伤。然而，我们最近确定， sAPP可以刺激小胶质细胞的促炎过程，小胶质细胞是一种单核细胞， 大脑有趣的是，sAPP的这两种不同的生物活性可以是 差异调节的遗传和生化决定因素，包括 与载脂蛋白E（ApoE）的物理相互作用。这些数据表明， 假设sAPP对神经元活力和功能的最终作用 结果从其神经保护和促炎的整合 活动，这些活动的平衡取决于sAPP结构 与ApoE的相互作用和变化。该假设将通过 以下目的：1）表征ApoE与 sAPP; 2）确定sAPP通过哪些信号转导机制 激活小胶质细胞中的炎症事件3）确定结构元件 负责APP的促炎活性; 4F）确定各种 sAPP的活性最终与神经元功能相结合 和生存将采用多种方法。溶液结合试验 将用于测量sAPP对各种ApoE同种型的亲和力。 小胶质细胞活化将通过亚硝酸盐产生的测定来测量， 细胞因子表达和神经毒性。这些终点将应用于 sAPP信号转导机制的药理学试验，这将是 辅以这些信号激活的生化测试 转导途径。缺失和位点特异性诱变将用于 描述sAPP促炎活性的结构决定因素， 它们可以与ApoE结合和相关信号传导所需的那些进行比较 事件神经元-小胶质细胞共培养和其他独特的培养系统将是 用于确定sAPP活动在水平上的最终相互作用 神经元存活和突触完整性的影响， 分子结构问题。这些研究可能揭示了一个关键组成部分， 阿尔茨海默病的发病机制，解释现有的影响，炎症 参与阿尔茨海默氏症，并提出针对 修改sAPP的动作。具体而言，阐明细胞的 sAPP激活小胶质细胞的机制可能为 阿尔茨海默病的治疗干预。

DESCRIPTION (Abstract): Increasing evidence points to a role for inflammation in Alzheimer's disease. Data also implicate metabolites of the beta-amyloid precursor protein (beta-APP) in the etiology of Alzheimer's disease. We previously have demonstrated that secreted forms of beta-APP (sAPP) protect neurons against several toxic insults. However, we recently determined that sAPP can stimulate proinflammatory processes in microglia, a monocytic cell in the brain. Interestingly, these two distinct bioactivities of sAPP can be differentially modulated by genetic and biochemical determinants, including a physical interaction with apolipoprotein E (ApoE). These data suggest the hypothesis that the ultimate effect of sAPP on neuronal viability and function results from the integration of its neuroprotective and proinflammatory activities, and that the balance of these activates depends on sAPP structural variations and interactions with ApoE. The hypothesis will be tested through the following objectives: 1) Characterize the interaction between ApoE and sAPP; 2) Determine the signal transduction mechanisms through which sAPP activates inflammatory events in microglia 3) Determine the structural elements responsible for APP's proinflammatory activity; 4F) Determine how various activities of sAPP are ultimately integrated with respect to neuronal function and survival. A diversity of methods will be applied. Solution binding assays will be used to measure the affinity of sAPP for various ApoE isoforms. Microglial activation will be measured through assays of nitrite production, cytokine expression, and neurotoxicity. These endpoints will be applied to pharmacological tests of sAPP signal transduction mechanisms, which will be complemented by biochemical tests of the activation of these signal transduction pathways. Deletional and site-specific mutagenesis will be used to delineate the structural determinants of sAPP proinflammatory activity so that they can be compared to those required for ApoE binding and relevant signaling events. Neuron-microglia co-cultures and other unique culture systems will be utilized to determine the ultimate interaction of sAPP activities at the level of neuronal survival and synaptic integrity, and its modulation by molecular-structure issues. These studies may reveal a key component of Alzheimer's pathogenesis, explain existing implications of inflammatory involvement in Alzheimer's, and suggest therapeutic strategies directed at modifying the actions of sAPP. Specifically, elucidation of the cellular mechanisms through which sAPP activates microglia may provide targets for therapeutic intervention in Alzheimer's disease.