Determinants of Notch-Sparing Gamma-Secretase Inhibition

保留缺口的γ分泌酶抑制的决定因素

• 批准号: 8488025
• 负责人: Michael S Wolfe
• 金额: $ 8.81万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8488025
• 关键词: Address; Affect; Alzheimer' s Disease; Amyloid; Amyloid Proteins; Amyloid beta-Protein Precursor; Aspartic Endopeptidases; Binding; Biochemical; Cell Differentiation process; Chimera organism; Cleaved cell; Clinical Trials; Complex; Development; Early Onset Familial Alzheimer' s Disease; Enzymes; Event; Goals; Integral Membrane Protein; Length; Membrane; Mind; Modeling; Multienzyme Complexes; Mutation; Pathogenesis; Pathway interactions; Peptide Hydrolases; Peptides; Pharmaceutical Preparations; Protein Precursors; Proteins; Proteolysis; Side; Signal Pathway; Site; Testing; Toxic effect; Transmembrane Domain; Work; design; drug candidate; enzyme substrate; extracellular; familial Alzheimer disease; gamma secretase; inhibitor/antagonist; interest; mutant; neurotoxic; notch protein; peptide A; presenilin; presenilin-1; public health relevance; research study; secretase; self assembly; therapeutic enzyme

DESCRIPTION (provided by applicant): The 4 kDa amyloid ?-protein (A?) is strongly implicated in the pathogenesis of Alzheimer's disease (AD). A? is produced through successive proteolysis of the type I integral membrane amyloid ?-protein precursor (APP), first on the lumen/extracellular side by the membrane-tethered ?-secretase and then within the transmembrane domain (TMD) by ?-secretase, a membrane-embedded aspartyl protease complex that contains the multi-pass presenilin as the catalytic component. Cleavage by ?-secretase determines the length of the A? peptide at the C-terminus, with longer forms of A? containing more of the TMD and being much more prone to self-assembly into neurotoxic aggregates. Although ?-secretase is considered an important target for the development of AD therapeutics, the enzyme cleaves a variety of other type I integral membrane proteins, most notably Notch receptors. Proteolysis of Notch with attendant release of its intracellular domain is part of a signaling pathway that is central to many types of cell differentiation events, and inhibition of this pathway with ?-secretase inhibitors (GSIs) results in severe toxicities that are unacceptable for an AD drug. Nevertheless, the discovery of GSIs that are selective for APP over Notch (so-called "Notch-sparing" GSIs) has led to the advancement of several candidates into clinical trials. However, the means by which these compounds selectively inhibit the protease complex are unknown, and an understanding of their mechanisms of selectivity might reveal strategies for developing more selective agents. The goal of this project is to identify substrate and enzyme determinants that confer selectivity for APP vis-?-vis Notch of Notch-sparing ?-secretase inhibitors. With this goal in mind, specific aims are proposed to address the following questions: (1) What regions/residues of APP and Notch confer substrate selectivity of Notch-sparing GSIs? (2) What is the potency and selectivity of Notch-sparing GSIs for ?-secretase carrying familial AD mutations? (3) What is the potency and selectivity of Notch-sparing GSIs for PS1 vs. PS2 ?-secretase? The identification of substrate and enzyme determinants of APP/Notch selectivity for these compounds should provide important information relevant to where these compounds bind and how that binding might result in allosteric changes that confer substrate selectivity.

描述（由申请人提供）： 4 kDa 淀粉样β-蛋白（Aβ）与阿尔茨海默氏病（AD）的发病机制密切相关。一个？是通过 I 型整合膜淀粉样蛋白 β-蛋白前体 (APP) 的连续蛋白水解产生的，首先在膜束缚的 β-分泌酶的作用下在腔/细胞外侧，然后在跨膜结构域 (TMD) 内由 β-分泌酶（一种膜嵌入的天冬氨酰蛋白酶复合物，包含多通道早老素作为催化） 成分。 β-分泌酶的切割决定了Aβ的长度。肽位于 C 末端，具有较长形式的 A？含有更多的 TMD，并且更容易自组装成神经毒性聚集体。尽管β-分泌酶被认为是开发 AD 疗法的重要靶点，但该酶可裂解多种其他 I 型整合膜蛋白，尤其是 Notch 受体。 Notch 的蛋白水解及其胞内结构域的释放是 β-分泌酶抑制剂 (GSI) 是信号通路的一部分，对许多类型的细胞分化事件至关重要，使用 β-分泌酶抑制剂 (GSI) 抑制该通路会导致严重的毒性， 对于 AD 药物来说是不可接受的。尽管如此，对 APP 而非 Notch 具有选择性的 GSI（所谓的“Notch 保留”GSI）的发现已促使数个候选药物进入临床试验。然而，这些化合物选择性抑制蛋白酶复合物的方式尚不清楚，了解它们的选择性机制可能会揭示开发更具选择性的药物的策略。该项目的目标是鉴定赋予 APP 相对于 Notch 或保留 Notch β-分泌酶抑制剂选择性的底物和酶决定簇。考虑到这一目标，提出了解决以下问题的具体目标：（1）APP和Notch的哪些区域/残基赋予Notch-sparing GSI的底物选择性？ (2) 保留Notch的GSI对于携带家族性AD突变的β-分泌酶的效力和选择性如何？ (3) 保留 Notch 的 GSI 对 PS1 与 PS2 β-分泌酶的效力和选择性如何？这些化合物的 APP/Notch 选择性的底物和酶决定因素的鉴定应提供与这些化合物结合位置以及该结合如何导致赋予底物选择性的变构变化相关的重要信息。