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

描述(申请人提供)：阿尔茨海默病(AD)的特征是淀粉样蛋白(A？)异常堆积。在大脑中为记忆和认知服务的区域。近年来，降解A？的蛋白水解酶被认为是体内脑A？水平和淀粉样蛋白生成的有效和限速调节因子。值得注意的是，激活A？降解酶的口服生物可用化合物已经被发现在动物模型中有效地减少AD类型的病理，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)是一种特别重要的A？降解酶。然而，令人惊讶的是，缺乏针对IDE的药理工具，或者实际上是针对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在药理上得到增强，包括内源性抑制物的置换或其表达和/或分泌到细胞外空间的调节。此外，IDE的新晶体结构表明，该酶具有非常规的结构特征，可以靶向直接激活该酶高达4000%。这项建议的目的是利用我们特征良好的基于荧光偏振的A？-降解实验(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。我们提出了一系列二次检测来确认已发现的HITS，以确定其对IDE的特异性，并鉴定细胞穿透性化合物。适合在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发病机制中的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解决。此外，具有合适性质的IDE化学激活剂可以作为药物载体用于开发新的AD治疗方法。

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.