Elucidating the biophysical and biological properties of the p3 fragment in Alzheimer's Disease

项目总结 阿尔茨海默病是美国第六大死因，影响着10%的65岁以上的老年人。 尽管有无数针对β-淀粉样蛋白的产生和清除的阿尔茨海默病治疗药物 (Aβ)肽，有效的治疗方法尚未确定。目前普遍接受的这种淀粉样蛋白模型 疾病只寻求了解Aβ的两种主要亚型的性质--含有40或42个氨基酸。 然而，从阿尔茨海默氏症患者大脑中分离出的斑块含有各种Aβ多肽和其他 蛋白质。这项拟议研究的长期目标是阐明Aβ和其 突变共同导致了阿尔茨海默病的病理。Aβ的C-末端片段p3具有 自发现以来一直被描述为可溶性和无淀粉样变性，尽管最低限度的科学研究 支持这一点的证据。我建议合成和表征聚集性和毒性机制。 P3以阐明其在淀粉样原纤维形成中的作用。我的假设是p3片段形成了淀粉样纤维。 能够给研究得很好的40和42长度Aβ的齐聚带来巨大的变化。海流 通过了解所有Aβ多肽的集体贡献可以显著改进淀粉样蛋白模型 通过它们的动力学相互作用。目的：我将提供关于p3如何聚集成淀粉样蛋白纤维以及如何 通过使用动力学分析、抗体和光诱导的交联剂，该途径偏离了Aβ。目标2 将创建一种更异质的模型，通过共孵育将淀粉样肽聚集成纤维 用p3和Aβ进行种子分析。目标3将提供我们对p3如何发挥其作用的理解的进展 对细胞的毒性以及该途径与Aβ的不同之处。P3毒性的机制将通过 多种双正交细胞摄取方法和细胞凋亡检测。完成列出的目标将阐明 P3在淀粉样斑块形成和细胞毒性动力学中的作用。通过提供对 关于p3的聚集性质和生物活性，拟议的工作将阐明p3如何与Aβ相互作用。 最终，我预计结果将修改和完善目前接受的淀粉样蛋白模型，提供 对阿尔茨海默病的病理有更全面的了解。

PROJECT SUMMARY Alzheimer’s Disease is the 6th leading cause of death in the U.S, affecting 10% of seniors over the age of 65. Despite the myriad Alzheimer’s Disease therapeutics targeting the production and clearance of the β-Amyloid (Aβ) peptide, an effective cure is yet to be identified. The current, commonly accepted amyloid model of this disease only seeks to understand the properties of two predominant isoforms of Aβ - with 40 or 42 amino acids. However, plaques isolated from the brains of Alzheimer’s patients contain a variety of Aβ peptides and other proteins. The long-term objective of the proposed research is to elucidate the mechanisms by which Aβ and its variants contribute collectively to the pathology of Alzheimer’s Disease. A C-terminal fragment of Aβ, p3, has been described as soluble and void of amyloidogenic properties since its discovery, despite minimal scientific evidence to support this. I propose to synthesize and characterize the aggregation and mechanism of toxicity of p3 to elucidate its role in amyloid fibril formation. My hypothesis is that the p3 fragment forms amyloid fibrils capable of imparting drastic changes on the oligomerization of the well-studied 40 and 42 length Aβ. The current amyloid model can be significantly improved by understanding the collective contribution of all Aβ peptides through their kinetic interactions. Aim I will provide insights on how p3 aggregates into amyloid fibrils and how that pathway deviates from Aβ with the use of kinetic assays, antibodies and photo-induced crosslinking. Aim 2 will create a more heterogenous model for the aggregation of amyloid peptides into fibrils through coincubation and seeding assays with p3 and Aβ. Aim 3 will provide advances in our understanding of how p3 exerts its toxicity on cells and how that pathway differs from that of Aβ. The mechanism of p3 toxicity will be explored with various biorthogonal cellular uptake methods and apoptosis assays. Completing the listed aims will elucidate the role that p3 plays in the kinetics of amyloid plaque formation and cell toxicity. By providing key insights into the aggregation properties and biological activity of p3, the proposed work will clarify how p3 interacts with Aβ. Ultimately, I expect the results to modify and refine the currently accepted amyloid model, providing a more comprehensive understanding of the pathology of Alzheimer’s Disease.