Inhibition of Alzheimer's Beta-Amyloid Fibril Formation

描述（由申请人提供）：阿尔茨海默病（AD）是一种进行性和不可逆的脑部疾病，目前尚无治愈方法。一种含有39-43个氨基酸的小蛋白质，淀粉样蛋白肽（Abeta），被广泛认为是这种疾病的罪魁祸首。最近的证据表明，可溶性β低聚物可能是阿尔茨海默病中淀粉样蛋白的主要毒性物质。在正常生理条件下，新合成的β是单体、可溶、无毒的，呈随机线圈/ α -螺旋混合结构。在AD中，β经历了从随机线圈/ α -螺旋结构到β -片结构的构象变化，导致寡聚化和沉淀。在寻找阻止这种构象变化的化合物时，我们发现一类三环pyroones (TP)，特别是CP2（代号），可以防止与细胞内含有abeta代谢物积累有关的人神经母细胞瘤MC65细胞的死亡。CP2抑制Abeta1-40和Abeta1-42肽的聚集，阻断Abeta1-40和Abeta1-42 β -sheet的形成，并在体外与Abeta肽结合。CP2也能穿透小鼠血脑屏障。这些令人兴奋的结果表明CP2可能作为一种治疗AD的药物。我们提出以下具体目标：(1)研究CP2及其类似物存在下Abeta40和Abeta42的结构变化和聚集状态；(2)确定了CP2阻断Abeta40和Abeta42 β -sheet形成和聚集的机制；(3)合成含C9、C11和C14官能团的TP和CP2类似物小文库；(4)细胞培养CP2类似物的体外生物活性研究；(5) CP2类似物对3xTg-AD APP小鼠体内药理作用的研究。本课题的最终目标是在动物模型中找到一种能够阻断Ab病变形成的先导化合物，从而开发出治疗AD的药物。CP2及其类似物在阿尔茨海默病药物开发中具有很大的潜力。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is a progressive and irreversible brain disorder with no known cure. A small protein, amyloid beta peptide (Abeta) containing 39-43 amino acids, is widely considered a culprit for the disease. Recent evidence indicates that soluble oligomers of Abeta may represent the primary toxic species of amyloid in AD. It is accepted that newly produced Abeta is monomeric, soluble and non-toxic, adopting random coil/alpha-helix mixture structures under normal physiological conditions. In AD, Abeta undergoes conformational changes from random coil/alpha-helix to beta-sheet structure, resulting in oligomerization and precipitation. In search of a compound that blocks this conformational change, we discovered that a class of tricyclic pyrones (TP), especially CP2 (code name), prevents the death of human neuroblastoma MC65 cells related to intracellular accumulation of Abeta-containing metabolites. CP2 inhibits the aggregation of Abeta 1- 40 and Abeta1-42 peptides, blocks Abeta1-40 and Abeta1-42 beta-sheet formation, and binds to Abeta peptides in vitro. CP2 also penetrated blood-brain barrier in mice. These exciting results suggest that CP2 may potentially serve as a drug to treat AD. We propose the following specific aims: (1) Studies of the structural changes and aggregation states of Abeta40 and Abeta42 in the presence of CP2 and analogs; (2) Identification of the mechanism by which CP2 blocks beta-sheet formation and aggregation of Abeta40 and Abeta42; (3) Syntheses of a small library of TP, new analogs of CP2 containing functional groups at C9, C11 and C14; (4) Studies of the in vitro bioactivities of CP2 analogs in cell cultures; and (5) Studies of the in vivo pharmacological effect of CP2 analogs with 3xTg-AD APP mice. The ultimate goal of this proposal are to identify a lead compound that is able to block the formation of Ab lesions in animal model, which may lead to drugs for the treatment of AD. CP2 and its analogs should have great potential in AD drug development. Relevance: Oligomerization of amyloid beta-peptide has been shown to be a major feature of the pathogenesis of AD. Monomeric Abeta is produced during normal metabolism and appears to have no toxic effects on neurons. However, soluble oligomeric Abeta showed high neuronal toxicity. Inhibition of the formation of these toxic soluble Abeta oligomers would provide therapeutics for AD.