Naveh Tassa Segev, Ben Zichri Shani, Lacham-Hartman Shiran, Oren Ofek, Slobodnik Zeev, Eremenko Ekaterina, Toiber Debra, Jelinek Raz, Papo Niv
Avram and Stella Goldstein-Goren Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel.
Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel.
ACS Chem Neurosci. 2021 May 5;12(9):1563-1577. doi: 10.1021/acschemneuro.1c00045. Epub 2021 Apr 27.
It is currently believed that molecular agents that specifically bind to and neutralize the toxic proteins/peptides, amyloid β (Aβ42), tau, and the tau-derived peptide PHF6, hold the key to attenuating the progression of Alzheimer's disease (AD). We thus tested our previously developed nonaggregating Aβ42 double mutant (Aβ42) as a multispecific binder for three AD-associated molecules, wild-type Aβ42, the tau mutant, and a synthetic PHF6 peptide. Aβ42 acted as a functional inhibitor of these molecules in assays and in neuronal cell-based models of AD. The double mutant bound both cytotoxic tau and synthetic PHF6 and protected neuronal cells from the accumulation of tau in cell lysates and mitochondria. Aβ42 also reduced toxic intracellular levels of calcium and the overall cell toxicity induced by overexpressed tau, synthetic PHF6, Aβ42, or a combination of PHF6and Aβ42. Aβ42 inhibited PHF6-induced overall mitochondrial dysfunction: In particular, Aβ42 inhibited PHF6-induced damage to submitochondrial particles (SMPs) and suppressed PHF6-induced elevation of the ζ-potential of inverted SMPs (proxy for the inner mitochondrial membrane, IMM). PHF6 reduced the lipid fluidity of cardiolipin/DOPC vesicles (that mimic the IMM) but not DOPC (which mimics the outer mitochondrial membrane), and this effect was inhibited by Aβ42. This inhibition may be explained by the conformational changes in PHF6 induced by Aβ42 in solution and in membrane mimetics. On this basis, the paper presents a mechanistic explanation for the inhibitory activity of Aβ42 against Aβ42- and tau-induced membrane permeability and cell toxicity and provides confirmatory evidence for its protective function in neuronal cells.
目前认为，特异性结合并中和有毒蛋白质/肽（淀粉样β蛋白（Aβ42）、tau蛋白以及tau衍生肽PHF6）的分子药物是减缓阿尔茨海默病（AD）进展的关键。因此，我们测试了我们之前开发的非聚集性Aβ42双突变体（Aβ42）作为三种AD相关分子（野生型Aβ42、tau突变体和合成PHF6肽）的多特异性结合剂。在实验和基于神经元细胞的AD模型中，Aβ42作为这些分子的功能抑制剂发挥作用。该双突变体与细胞毒性tau和合成PHF6均结合，并保护神经元细胞免受tau在细胞裂解物和线粒体中的积累。Aβ42还降低了细胞内有毒的钙水平以及由过表达的tau、合成PHF6、Aβ42或PHF6与Aβ42组合诱导的整体细胞毒性。Aβ42抑制了PHF6诱导的整体线粒体功能障碍：特别是，Aβ42抑制了PHF6诱导的亚线粒体颗粒（SMP）损伤，并抑制了PHF6诱导的倒置SMP（线粒体内膜（IMM）的替代物）ζ电位升高。PHF6降低了心磷脂/DOPC囊泡（模拟IMM）的脂质流动性，但未降低DOPC（模拟线粒体外膜）的脂质流动性，而Aβ42抑制了这种作用。这种抑制作用可能是由于溶液中和膜模拟物中Aβ42诱导的PHF6构象变化所致。在此基础上，本文对Aβ42对Aβ42和tau诱导的膜通透性及细胞毒性的抑制活性提出了一种机制解释，并为其在神经元细胞中的保护功能提供了确证证据。
