GLIAL B-AMYLOID PEPTIDE RECEPTORS IN ALZHEIMER'S DISEASE

阿尔茨海默病中的胶质 B 淀粉样肽受体

• 批准号: 3488131
• 负责人: KURT R. BRUNDEN
• 金额: $ 5万
• 依托单位: GLIATECH, INC.
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-15 至 1993-09-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3488131
• 关键词: Alzheimer's disease; amyloid proteins; arachidonate; astrocytes; cell death; enzyme complex; glia; human tissue; interleukin 1; laboratory rat; microglia; neuritic plaques; neuropeptide receptor; prostaglandin E; radioimmunoassay; receptor binding; substance P

DESCRIPTION (Adapted from applicant's abstract): One of the pathological hallmarks of Alzheimer's Disease is the presence of senile plaques containing beta-amyloid peptide (BAP). These plaques seem to be different from ordinary amyloid plaques in that they have microglia and astrocytes within and around the condensed core of the plaque. This observation prompted the hypothesis that microglia and astrocytes may play a crucial role in plaque formation and the pathology of Alzheimer's disease. Dr. Brunden has postulated that these glia have surface receptors for BAP and has put forth a theory of biochemical events which may lead to Alzheimer's Disease pathology. The theory goes something like this: Glia have substance P receptors. Microglia are the CNS equivalent of macrophages, and macrophages have a receptor called the serpin-enzyme complex (SEC) which binds both substance P and BAP. Thus, the PI postulates that glia have a SEC receptor or specific receptor for BAP. He further postulates that the BAP binding on glial surface receptors induces release of interleukin 1 (IL-1). The increased IL-1 could cause increased amyloid precursor protein (APP), of which BAP is a proteolytic bye product, and thereby advanced Alzheimer's Disease by increasing BAP even further. It is also postulated that IL-1 increases arachidonic acid and prostaglandin E2 (PGE2), thereby inducing glutamic acid uptake by astrocytes. This could result in excessive glutamate levels that would be excitotoxic and lead to neural cell death, thus promoting Alzheimer's Disease. As a preliminary data, the principal investigator has employed both a human glioblastoma cell line, U373 MG, and neonatal rat primary astrocetermine indirectly if these cells contains receptors that recognize both BAP and substance P (putative SEC receptors). Dr. Brunden found that 125I-substance P binds specifically to these glial cells. Using competitive binding assays he also showed that this binding was inhibited by the amino acid residues BAP (1-40) and BAP (25-35), but not by BAP (1-28). These results suggests that a SEC receptor may exist on glial cells. The proposed aims are: 1] to examine 125I-BAP (1-40) binding to microglia and astrocytes in culture for the presence of BAP receptors. Satchard analyses and competition studies will be used to demonstrate saturability, affinity and specificity of BAP binding. 2] to determine if BAP binding to receptors in astrocyte and microglia cultures increases IL-1 secretion. This will be assessed using a variation of the thymocyte costimulation bioassay which measures the proliferation of a certain T helper cell line that occurs after concanavalin A stimulation, only if exogenous IL-1 is present. 3] to determine if BAP binding induces the release of PGE2 from microglia, astrocytes or mixed glial cultures. The PGE2 will be measured using a commercial RIA kit. If the demonstration of the proposed "cascade" of cellular events is successful, the Phase II application would employ various inhibitors and antagonists (eg. to BAP, IL-1, PGE2 synthesis) to investigate possible mechanisms of halting of slowing the progress of Alzheimer's Disease.

描述（改编自申请人的摘要）：病理学之一 阿尔茨海默病的特征是存在老年斑 含有β-淀粉样肽（BAP）。 这些牌匾似乎是 与普通淀粉样斑块不同的是，它们具有小胶质细胞和 斑块凝结核心内部和周围的星形胶质细胞。 这 观察结果提出了这样的假设：小胶质细胞和星形胶质细胞可能 在斑块形成和阿尔茨海默病的病理学中起着至关重要的作用 疾病。布伦登博士假设这些神经胶质细胞具有表面 BAP 受体并提出了生化事件理论 可能导致阿尔茨海默病的病理变化。 理论是有道理的 像这样：神经胶质细胞有 P 物质受体。 小胶质细胞是中枢神经系统 相当于巨噬细胞，巨噬细胞有一种受体，称为 丝氨酸蛋白酶抑制剂-酶复合物 (SEC)，可结合 P 物质和 BAP。因此， PI 假设神经胶质细胞具有 SEC 受体或特定受体 BAP。 他进一步假设 BAP 结合在神经胶质表面 受体诱导白细胞介素 1 (IL-1) 的释放。 IL-1增加 可能会导致淀粉样前体蛋白（APP）增加，其中BAP是 一种蛋白水解副产物，从而导致阿尔茨海默病的进展 进一步增加 BAP。 还假设 IL-1 增加 花生四烯酸和前列腺素 E2 (PGE2)，从而诱导谷氨酸 星形胶质细胞对酸的摄取。 这可能会导致谷氨酸过量 会产生兴奋毒性并导致神经细胞死亡的水平，因此 促进阿尔茨海默病。 作为初步数据，主要研究者采用了 人胶质母细胞瘤细胞系、U373 MG 和新生大鼠原代 如果这些细胞含有以下受体，则间接产生星西特明 识别 BAP 和 P 物质（假定的 SEC 受体）。布伦登博士 发现 125I-P 物质与这些神经胶质细胞特异性结合。 使用竞争性结合测定，他还表明这种结合是 受氨基酸残基 BAP (1-40) 和 BAP (25-35) 抑制，但不 通过 BAP (1-28)。 这些结果表明 SEC 受体可能存在于 胶质细胞。 拟议的目标是： 1] 检查 125I-BAP (1-40) 与小胶质细胞的结合 和培养中的星形胶质细胞以确定 BAP 受体的存在。萨查德 分析和竞争研究将用于证明 BAP 结合的饱和度、亲和力和特异性。 2]确定 如果 BAP 与星形胶质细胞和小胶质细胞培养物中受体的结合增加 IL-1的分泌。 这将使用胸腺细胞的变体进行评估 共刺激生物测定，测量某种 T 的增殖 伴刀豆球蛋白 A 刺激后出现的辅助细胞系，仅当 存在外源性 IL-1。 3]确定BAP结合是否诱导 小胶质细胞、星形胶质细胞或混合胶质细胞培养物中释放 PGE2。 这 PGE2 将使用商业 RIA 试剂盒进行测量。 如果所提出的细胞事件“级联”的演示是 如果成功，第二阶段的应用将采用各种抑制剂和 拮抗剂（例如 BAP、IL-1、PGE2 合成）以研究可能的 阻止或减缓阿尔茨海默病进展的机制。