HTS for Modulators of Beta-Amyloid Catabolism by Insulin-Degrading Enzyme

描述（由申请人提供）：阿尔茨海默病（AD）的特征是淀粉样蛋白异常积聚？-蛋白（A?）在大脑中负责记忆和认知的区域。近年来，降解A?？已被确定为脑A的有效和限速调节剂？？水平和体内淀粉样蛋白的形成。值得注意的是，激活A？-降解蛋白酶已经被发现在动物模型中有效地减少ad型病理，目前正在进入临床试验。越来越多的证据强烈暗示胰岛素降解酶（IDE）是一个特别重要的a ？有辱人格的蛋白酶。然而，令人惊讶的是，缺乏针对IDE的药理学工具，或者它所属的不寻常的锌金属蛋白酶超家族的任何成员。重要的是，越来越多的证据表明，IDE活性可能通过几种机制中的任何一种增强药理学作用，包括取代内源性抑制剂或调节其表达和/或分泌到细胞外空间。此外，IDE的新晶体结构表明，该蛋白酶具有非正统的结构特征，可以靶向直接激活蛋白酶高达400%。本提案的目的是利用我们具有良好特征的基于荧光偏振的A？-降解试验（Leissring等人，JBC 2003，附录）在MLSCN的小分子文库中寻找IDE的化学调节剂。我们提出了一系列的二级分析，以确认发现的命中，以建立他们的特异性IDE，并确定细胞渗透化合物。适合于培养细胞或体内使用的探针将用于下游实验，以解决IDE在AD发病机制中作用的几个悬而未决的问题，这些问题只能通过化学生物学方法来解决。此外，具有合适性质的IDE化学激活剂可作为开发新型AD疗法的药效载体。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is characterized by abnormal accumulation of the amyloid ?-protein (A?) in brain regions subserving memory and cognition. In recent years, proteases that degrade A??have been identified as potent and rate-limiting regulators of cerebral A??levels and amyloidogenesis in vivo. Significantly, orally bioavailable compounds that activate A?-degrading proteases have already been identified that are effective in reducing AD-type pathology in animal models and are currently entering clinical trials. Converging lines of evidence strongly implicate insulin-degrading enzyme (IDE) as a particularly important A?-degrading protease. Nonetheless, there is a surprising lack of pharmacological tools targeting IDE, or indeed any member of the unusual zinc-metalloprotease superfamily to which it belongs. Importantly, accumulating evidence shows how IDE activity might be augmented pharmacologically by any of several mechanisms, including the displacement of endogenous inhibitors or modulation of its expression and/or secretion into the extracellular space. Moreover, new crystal structures of IDE show that this protease possesses unorthodox structural features that can be targeted to directly activate the protease as much as 4000 percent. The purpose of this proposal is to utilize our well-characterized fluorescence polarization-based A?-degradation assay (Leissring et al., JBC 2003, Appendix) to search for chemical modulators of IDE within the Small Molecule Library of the MLSCN. We propose a series of secondary assays to confirm discovered hits, to establish their specificity for IDE, and to identify cell-penetrant compounds. Probes suitable for use in cultured cells or in vivo will be used in downstream experiments to resolve several outstanding questions about the role of IDE in AD pathogenesis that can only be addressed via a chemical biology approach. In addition, chemical activators of IDE with suitable properties could serve as pharmacophores for the development of novel AD therapies.