A screen for molecules that inhibit formation of A-beta oligomers in yeast

描述（由申请人提供）：阿尔茨海默病（AD）是一种影响大量老年人的神经系统疾病。其特征在于脑中斑块的形成，所述斑块主要由β-淀粉样肽（A-β）的SDS抗性原纤维组成。大量证据支持淀粉样蛋白级联假说，该假说提出A-β肽的积累触发AD的出现。虽然早期证据表明A-β淀粉样蛋白原纤维具有神经毒性，但最近的研究指出SDS稳定低聚物（已在体内和体外检测到）是主要的神经毒性物质。一种有希望的治疗AD的新兴方法是防止这些寡聚体形成。事实上，破坏这些低聚物而不是较大的原纤维似乎是谨慎的，因为抑制A-β原纤维形成可能导致有害的低聚物种类积累，并且因为抑制低聚物形成也应该防止原纤维的初始形成。目前，还没有一种简单的寡聚体形成的测定方法可以直接筛选这些药物。我们正在开发A-β寡聚化的酵母模型系统，以提供一种有助于此类直接药物筛选的测定方法。该系统采用A-β与酵母翻译释放因子（RF）的融合。RF报告基因仅在融合体不寡聚化的情况下才具有活性并允许细胞在测试培养基上生长。使用这个模型系统，我们将开发一个高通量的测定，这将使我们能够筛选小分子，抑制A-β依赖的寡聚化的翻译释放因子。我们的目标是创建一种检测方法，使我们能够通过简单地选择允许或抑制测试培养基上生长的小分子来检测A-β聚集的寡聚化阶段的破坏。最终，通过观察我们检测中活性分子的结构，将有可能设计出增强其阻断A-β寡聚化能力的化合物，并作为人类治疗或预防阿尔茨海默病的药物。最后，还需要进行动物和人体试验。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is a neurological disorder that effects large numbers of elderly people. It is characterized by the formation of plaques in the brain that are largely composed of SDS resistant fibrils of beta-amyloid peptide (A-beta). A considerable body of evidence supports the amyloid cascade hypothesis that proposes that accumulation of A-beta peptide triggers the appearance of AD. While early evidence indicated that the A-beta amyloid fibrils are neuro-toxic, recent research points to the SDS stable oligomers (that have been detected both in vivo and in vitro) as the primary neuro-toxic species. One promising emerging approach for the treatment of AD is to prevent these oligomers from forming. Indeed, disruption of these oligomers rather than the larger fibrils seems prudent since inhibition of A-beta fibril formation might cause the harmful oligomer species to accumulate and since inhibiting oligomer formation should also prevent the initial formation of the fibrils. Currently there are no simple assays for oligomer formation that would allow a direct screen for such drugs. We are developing a yeast model system of A-beta oligomerization to provide an assay that will facilitate such a direct drug screen. The system employs a fusion of A-beta to the yeast translational release factor (RF). The RF reporter will only be active and allow cells to grow on test media if the fusion does not oligomerize. Using this model system, we will develop a high throughput assay that will allow us to screen for small molecules that inhibit the A-beta dependent oligomerization of the translational release factor. Our goal is to create an assay that allows us to detect disruption of the oligomerization stage of A-beta aggregation by simply selecting for small molecules that permit or inhibit growth on test media. Eventually by looking at the structure of the molecules active in our assay it will be possible to design compounds that enhance their ability to block A-beta oligomerization and to work as a drug in humans to treat or prevent Alzheimer's disease. Finally, animal and human trials would be required.