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: 6288710
• 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/6288710
• 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 Alzheimers 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 intracellular production and extracellular deposition of A-beta peptides in senile plaques of AD. The processing of APP also generates secreted forms of the protein which may have neurotrophic properties. Brains of AD patients exhibit selective and massive neuronal loss. In light of recent evidence from our laboratory showing that, in cell culture, over-expression of familial AD mutated forms of APP and PS causes apoptotic cell death, we are interested in examining the mechanisms involved in this cell death. One of the aims of our laboratory is to discover how APP or PS mutations lead to specific neuronal cell loss in AD.Previously we showed that over-expression of mutated forms of APP in stably transfected PC12 cells led to an increased production of intracellular, amyloidogenic C-terminal fragments of APP. This was accompanied by increased apoptotic cell death over several days. We recently showed that over-expression of FAD mutant APP by adenovirus-mediated gene transfer leads to cell death of primary cortical neurons. Increased amounts of carboxyl terminal APP fragments and A-beta peptide were detected intracellularly. The overexpression led to about a four-fold increase in apoptotic cell death over 72 hours as measured by an ELISA method detecting fragmented DNA bound to oligonucleosomes. In addition wild-type APP over-expression caused an increase in cell death suggesting that elevated levels of normal APP may have neurotoxic characteristics. This cell death in primary cortical neurons and by extension, in AD, may result from an imbalance in the generation of neurotoxic and neurotrophic processing products of APP. These products may act within the cell or may have a paracrine effect, being released into the media to affect neighboring cells. These results provide a rationale for targeting particular elements of apoptotic pathways and APP processing for therapeutic intervention in AD. - amyloid, A-beta peptide, aging, neurodegeneration, apoptosis

工作概要：本项目的一个主要重点是发现淀粉样前体蛋白（APP）在阿尔茨海默病（AD）病因和病理中的作用。这种蛋白质的正常生理作用也在研究中。APP是重要的研究，因为APP的加工和早老素（PS）突变对APP加工的影响直接关系到AD老年斑中A-β肽的细胞内产生和细胞外沉积的增加。APP的加工还产生可能具有神经营养特性的蛋白质的分泌形式。AD患者的大脑表现出选择性和大量的神经元损失。鉴于我们实验室最近的证据表明，在细胞培养中，家族性AD突变形式的APP和PS的过度表达导致凋亡性细胞死亡，我们有兴趣研究这种细胞死亡中涉及的机制。我们实验室的目的之一是发现APP或PS突变如何导致AD中特定的神经元细胞丢失。以前我们发现，在稳定转染的PC 12细胞中，APP突变形式的过度表达导致细胞内APP淀粉样蛋白C末端片段的产生增加。我们最近发现，通过腺病毒介导的基因转移过度表达FAD突变APP导致原代皮层神经元细胞死亡。细胞内检测到羧基末端APP片段和A-β肽的量增加。通过检测与寡核小体结合的片段化DNA的ELISA方法测量，过表达导致72小时内凋亡性细胞死亡增加约4倍。此外，野生型APP过度表达导致细胞死亡增加，表明正常APP水平升高可能具有神经毒性特征。这种细胞死亡在初级皮质神经元，并通过扩展，在AD中，可能会导致在APP的神经毒性和神经营养加工产品的产生不平衡。这些产品可能会在细胞内发挥作用，或可能有旁分泌效应，被释放到媒体影响邻近细胞。这些结果提供了一个基本原理，针对特定元素的凋亡途径和APP处理的治疗干预AD。- 淀粉样蛋白，A-β肽，衰老，神经退行性变，凋亡