Specific amyloid-beta oligomer aptamers

描述(由申请人提供)：这项提案的中心重点是探索如何填补一个技术空白--在活体受试者中检测特定的A？寡聚体。测量活着个体中特定A低聚体的新技术的发展将使我们能够调查产生A56、A二聚体和A三聚体的个体在临床可识别的AD迹象出现之前可能存活多久。这个项目可能会提高我们对启动AD的过程的理解，以及我们在AD最早阶段诊断AD的能力，方法是确定特定的A？寡聚体是否足够早地出现在AD中，从而成为旨在完全预防疾病的治疗的靶点。如果成功，这项工作将使美国和世界数百万人受益。最近，我们与拉什大学的研究人员合作，发现许多没有认知障碍的老年人A56水平升高，如果他们活得更长，他们可能会患上阿尔茨海默病。我们还发现，在AD的发展和进展的不同阶段，不同的A？寡聚体水平升高。其他研究人员错过了不同低聚物起落的这些错综复杂的模式，因为他们使用的是测量大量低聚物的测试，而不区分不同的物种。对我们的假设的一种检验，即A？56引发AD，是为了观察A？56在大脑中的长期后果。然而，由于我们无法监测活体受试者大脑中的A56，我们将取而代之地在容易获得的测试样本中测量A56，最好是血液，但也包括脊髓液。使用我们目前的免疫印迹方法，我们可以在大脑和脊髓液中检测到A56，但在血液中检测不到。这表明血液中的A56水平极低，或者根本不存在。然而，在APP转基因小鼠中，有间接证据表明血液中存在A56。在过去的几年里，斯里南德·斯里瓦特桑实验室的研究人员开发出了DNA适配子，能够在远低于免疫印迹方法检测阈值的情况下，检测感染瘙痒病的绵羊血液中PrP蛋白的同种形式。最近，罗纳德·彼得森博士领导的梅奥诊所的研究人员完成了明尼苏达州罗切斯特市近2000名老年居民的招募，进行了一项关于衰老和早期认知问题的遗传、生物标记物和成像方面的纵向研究，并同意向我们提供脊髓液和血液样本。在这项挑战拨款申请中，我们建议与Sreevatsan博士合作开发能够检测特定A？寡聚体的DNA适配子，并使用这些适配子来测量Mayo诊所队列的脊髓液和血液中不同的A？低聚体，包括A？*56。 与公共卫生相关：这项提案的中心重点是探索如何填补技术空白--在活着的受试者中检测特定的A？寡聚体。测量活着个体中特定A低聚体的新技术的发展将使我们能够调查产生A56、A二聚体和A三聚体的个体在临床可识别的AD迹象出现之前可能存活多久。这个项目可能会提高我们对启动AD的过程的理解，以及我们在AD最早阶段诊断AD的能力，方法是确定特定的A？寡聚体是否足够早地出现在AD中，从而成为旨在完全预防疾病的治疗的靶点。如果成功，这项工作将使美国和世界数百万人受益。

DESCRIPTION (provided by applicant): The central focus of this proposal explores how to fill a technological gap - the detection of specific A¿ oligomers in living subjects. The development of new techniques for measuring specific A¿ oligomers in living individuals will enable us to investigate how long individuals that are producing A¿*56, A¿ dimers and A¿ trimers may live before clinically recognizable signs of AD emerge. This project may improve both our understanding of the processes that initiate AD and our ability to diagnose it in its earliest stages, by determining whether specific A¿ oligomers appear early enough in AD to become a target for therapies aimed at preventing the illness altogether. If successful, the work could benefit millions of people in America and the world. Recently, in collaboration with researchers at Rush University, we found that A¿*56 levels were elevated in many elderly individuals with no cognitive impairment who, presumably, would have developed AD had they lived longer. We also showed that distinct A¿ oligomers were elevated in different phases of the development and progression of AD. Other researchers have missed these intricate patterns in the rise and fall of distinct A¿ oligomers, because they used tests which measure A¿ oligomers in bulk, without distinguishing between distinct species. One test of our hypothesis, that A¿*56 initiates AD, is to observe the long-term consequences of A¿*56 in the brain. However, since we cannot monitor A¿*56 in the brains of living subjects, we will instead measure A¿*56 in readily accessible test specimens, preferably blood, but also spinal fluid. Using our current immunoblotting methods we can detect A¿*56 in brain and spinal fluid, but not in blood. This suggests that the levels of A¿*56 in blood are extremely low, or absent. However, there is indirect evidence in APP transgenic mice that A¿*56 is present in the blood. In the past few years, researchers in the laboratory of Dr. Srinand Sreevatsan developed DNA aptamers capable of detecting the scrapie isoform of the prion protein in the blood of scrapie-infected sheep, at levels far below the detection threshold of immunoblotting methods. Lately, researchers at the Mayo Clinic led by Dr. Ronald Petersen completed enrollment of nearly 2,000 elderly residents of Rochester, Minnesota, in a longitudinal study of genetic, biomarker, and imaging aspects of aging and very early cognitive problems, and have agreed to make spinal fluid and blood samples available to us. In this Challenge grant application, we propose to collaborate with Dr. Sreevatsan to develop DNA aptamers which detect specific A¿ oligomers, and to use these aptamers to measure distinct A¿ oligomers, including A¿*56, in the spinal fluid and blood of the Mayo Clinic cohort. PUBLIC HEALTH RELEVANCE: The central focus of this proposal explores how to fill a technological gap - the detection of specific A¿ oligomers in living subjects. The development of new techniques for measuring specific A¿ oligomers in living individuals will enable us to investigate how long individuals that are producing A¿*56, A¿ dimers and A¿ trimers may live before clinically recognizable signs of AD emerge. This project may improve both our understanding of the processes that initiate AD and our ability to diagnose it in its earliest stages, by determining whether specific A¿ oligomers appear early enough in AD to become a target for therapies aimed at preventing the illness altogether. If successful, the work could benefit millions of people in America and the world.