Buneeva O A, Gnedenko O V, Medvedeva M V, Ivanov A S, Medvedev A E
Institute of Biomedical Chemistry, Moscow, Russia; Higher School of Economics, Moscow, Russia.
Moscow State University, Moscow, Russia.
Biomed Khim. 2018 Sep;64(5):423-428. doi: 10.18097/PBMC20186405423.
Amyloid-β peptide (1-42) (Aβ1-42) is a key player in the development and progression of Alzheimer's disease (AD) and related pathologies, determined by formation of protein aggregates in the central nervous system. Aβ1-42 binding to crucial intracellular targets (and their subsequent inactivation) obviously represents one of the earliest events preceding extracellular pathogenic oligomerization/aggregation of Aβ1-42. It is reasonable to expect that dissociation of the Aβ1-42 complexes with intracellular proteins by means of inhibitors followed by subsequent degradation of Aβ1-42 would not only protect critically important proteins but also prevent intracellular accumulation of Aβ1-42. The aim of this study was to investigate the effect of the neuroprotector isatin (100 mM) on interaction of known Aβ-binding proteins, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and pyruvate kinase, with Aβ1-42 and its fragments (Aβ1-28, Aβ12-28, Aβ25-35). Aβ1-42 and its fragments (Aβ1-28, Aβ12-28, Aβ25-35) immobilized on the Biacore optical biosensor chip interacted with GAPDH and pyruvate kinase. The lowest and basically equal Kd values were determined for GAPDH and pyruvate kinase complexes with immobilized Aβ1-42 and Aβ25-35. The presence of 100 mM isatin caused a significant (more than fivefold) increase in the Kd values for GAPDH complexes with all Aβ peptides except Aβ1-28. In contrast to GAPDH isatin increased dissociation of pyruvate kinase complexes only with Aβ1-42 (causing a 30-fold increase in Kd) and to a lesser extent with Aβ12-28 and Aβ25-35 (a 10-fold increase in Kd). It should be noted that in the presence of isatin the Kd values for GAPDH and pyruvate kinase complexes with all Aβ studied were in a narrower concentration range (10-7 M - 10-6 M) than in the absence of this neuroprotector (10-8 M - 10-6 M). Data obtained suggest existence of principal possibility of (pharmacological) protection of crucial intracellular targets against both Aβ1-42, and its aggressive truncated peptides (Aβ25-35).
淀粉样β肽（1 - 42）（Aβ1 - 42）是阿尔茨海默病（AD）及相关病理发展和进程中的关键因素，其由中枢神经系统中蛋白质聚集体的形成所决定。Aβ1 - 42与关键细胞内靶点的结合（以及随后的失活）显然是Aβ1 - 42细胞外致病性寡聚化/聚集之前最早的事件之一。可以合理预期，通过抑制剂使Aβ1 - 42与细胞内蛋白质的复合物解离，随后降解Aβ1 - 42，不仅可以保护至关重要的蛋白质，还能防止Aβ1 - 42在细胞内的积累。本研究的目的是研究神经保护剂异吲哚酮（100 mM）对已知的Aβ结合蛋白甘油醛 - 3 - 磷酸脱氢酶（GAPDH）和丙酮酸激酶与Aβ1 - 42及其片段（Aβ1 - 28、Aβ12 - 28、Aβ25 - 35）相互作用的影响。固定在Biacore光学生物传感器芯片上的Aβ1 - 42及其片段（Aβ1 - 28、Aβ12 - 28、Aβ25 - 35）与GAPDH和丙酮酸激酶相互作用。测定了GAPDH和丙酮酸激酶与固定化Aβ1 - 42和Aβ25 - 35形成的复合物的最低且基本相等的解离常数（Kd）值。100 mM异吲哚酮的存在导致GAPDH与除Aβ1 - 28之外的所有Aβ肽形成的复合物的Kd值显著（超过五倍）增加。与GAPDH不同，异吲哚酮仅增加丙酮酸激酶与Aβ1 - 42形成的复合物的解离（导致Kd增加30倍），而对与Aβ12 - 28和Aβ25 - 35形成的复合物的解离影响较小（Kd增加10倍）。应该注意的是，在存在异吲哚酮的情况下，GAPDH和丙酮酸激酶与所有研究的Aβ形成的复合物的Kd值比不存在这种神经保护剂时的浓度范围更窄（10 - 7 M - 10 - 6 M）（10 - 8 M - 10 - 6 M）。所获得的数据表明存在对关键细胞内靶点进行（药理学）保护以对抗Aβ1 - 42及其具有侵袭性的截短肽（Aβ25 - 35）的主要可能性。
