REGULATION AND PROCESSING OF AMYLOID PRECURSOR PROTEIN GENES AND GENE PRODUCTS

淀粉样前体蛋白基因和基因产物的调控和加工

• 批准号: 6431422
• 负责人: JOHN W KUSIAK
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6431422
• 关键词: Alzheimer's disease; G protein; PC12 cells; aging; amyloid proteins; apoptosis; biological signal transduction; calcium flux; gene expression; gene mutation; oxidative stress; protein tyrosine kinase; tissue /cell culture

Summary of Work: A major focus of this project is to discover the role of the Amyloid Precursor Protein (APP) in the etiology and pathology of Alzheimer's Disease (AD). The normal physiological role of this protein is also under investigation. APP is important to study since the processing of APP and the effect of Presenilin (PS) mutations on APP processing bear directly on the increased production and extracellular deposition of A-beta peptides in AD. The processing of APP also generates two secreted forms of the protein, which may have neurotrophic or neurotoxic properties. Brains of AD patients exhibit decreased synaptic connectivity and selective and massive neuronal loss. We are interested in examining the mechanisms involved in this cell death. Previously, we showed that over-expression of FAD mutant forms of APP in stably transfected PC12 cells led to increased apoptotic cell death over several days and that over-expression of these same APPs by adenovirus-mediated gene transfer led to cell death of primary cortical neurons. More recently, we have been studying the effects of several A-beta peptides on human neuroblastoma and astrocytoma cells. Low concentrations of A-beta 1-42 kill SH-SY5Y cells by apoptosis as measured by an ELISA method while higher concentrations kill by necrosis. A-beta 1-40 is much less potent. A-beta 17-42, derived from APP by alpha- and gamma-secretase cutting of APP, dose-dependently kills these cells apoptotically. Early changes in gene expression after A-beta peptide treatment of these cells as monitored by cDNA array techniques include increases in apoptosis-related and oxidative stress-related genes and decreases in neurotrophic factor and growth-related proto-oncogenes. Treatment of astrocytoma cells with A-beta peptides leads to their activation and induction of MCP-1 gene transcription and protein synthesis. Initial studies suggest that A-beta 1-42 and 1-40 are activating these cells by different signal transduction pathways. These results provide a rationale for targeting particular elements of apoptotic and inflammatory pathways as well as APP processing for therapeutic intervention in AD.

工作总结：该项目的主要重点是发现淀粉样蛋白前体蛋白（APP）在阿尔茨海默氏病（AD）的病因和病理学中的作用。该蛋白质的正常生理作用也正在研究中。 APP对于研究很重要，因为APP的处理以及Presenilin（PS）突变对APP处理的影响直接对AD中A-Beta肽的生产和细胞外沉积的增加。 APP的加工还会产生两种分泌的蛋白质形式，它们可能具有神经营养或神经毒性。 AD患者的大脑表现出降低的突触连通性以及选择性和大量神经元丧失。我们有兴趣检查该细胞死亡所涉及的机制。以前，我们表明，在稳定转染的PC12细胞中，APP的FAD突变形式的过表达导致凋亡细胞死亡增加了几天，并且通过腺病毒介导的基因转移对这些相同的APP的过表达导致原发性皮质神经元的细胞死亡。最近，我们一直在研究几种A-beta肽对人神经母细胞瘤和星形细胞瘤细胞的影响。低浓度的A-beta 1-42通过通过ELISA方法测量的凋亡杀死SH-SY5Y细胞，而较高的浓度被坏死杀死。 A-Beta 1-40的效力要少得多。 A-Beta 17-42，由APP的APP衍生自APP的APP衍生而来，剂量依赖性地依赖性地杀死这些细胞。 A-β肽治疗这些细胞后，基因表达的早期变化是由cDNA阵列技术监测的，包括凋亡相关和氧化应激相关基因的增加，以及神经营养因子和与生长相关的原始癌基因的降低。用A-β肽对星形细胞瘤细胞的处理导致其激活和诱导MCP-1基因转录和蛋白质合成。初步研究表明，A-BETA 1-42和1-40正在通过不同的信号转导途径激活这些细胞。这些结果为靶向凋亡和炎症途径的特定要素以及用于AD治疗干预的应用程序提供了理由。