The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, PO Box 653, Beer Sheva 84105, Israel.
Department of Biotechnology Engineering, Faculty of Engineering, Ben-Gurion University of the Negev, PO Box 653, Beer Sheva 84105, Israel.
Biochem J. 2018 Oct 9;475(19):3087-3103. doi: 10.1042/BCJ20180247.
Aggregation and accumulation of the 42-residue amyloid β peptide (Aβ42) in the extracellular matrix and within neuronal cells is considered a major cause of neuronal cell cytotoxicity and death in Alzheimer's disease (AD) patients. Therefore, molecules that bind to Aβ42 and prevent its aggregation are therapeutically promising as AD treatment. Here, we show that a non-self-aggregating Aβ42 variant carrying two surface mutations, F19S and L34P (Aβ42), inhibits wild-type Aβ42 aggregation and significantly reduces Aβ42-mediated cell cytotoxicity. In addition, Aβ42 inhibits the uptake and internalization of extracellularly added pre-formed Aβ42 aggregates into cells. This was the case in both neuronal and non-neuronal cells co-expressing Aβ42 and Aβ42 or following pre-treatment of cells with extracellular soluble forms of the two peptides, even at high Aβ42 to Aβ42 molar ratios. In cells, Aβ42 associates with Aβ42, while , the two soluble recombinant peptides exhibit nano-molar binding affinity. Importantly, Aβ42 potently suppresses Aβ42 amyloid aggregation , as demonstrated by thioflavin T fluorescence and transmission electron microscopy for detecting amyloid fibrils. Overall, we present a new approach for inhibiting Aβ42 fibril formation both within and outside cells. Accordingly, Aβ42 should be evaluated for potential use as a therapeutic lead for treating AD.
淀粉样β肽（Aβ42）的 42 个残基在细胞外基质和神经元细胞内聚集和积累被认为是阿尔茨海默病（AD）患者神经元细胞毒性和死亡的主要原因。因此，与 Aβ42 结合并阻止其聚集的分子作为 AD 治疗具有很大的治疗潜力。在这里，我们表明，携带两个表面突变 F19S 和 L34P 的非自聚集 Aβ42 变体（Aβ42）抑制野生型 Aβ42 聚集，并显著降低 Aβ42 介导的细胞毒性。此外，Aβ42 抑制细胞外添加的预形成 Aβ42 聚集体进入细胞的摄取和内化。这在共表达 Aβ42 和 Aβ42 的神经元和非神经元细胞中以及在用两种肽的细胞外可溶性形式预先处理细胞后都是如此，即使在 Aβ42 与 Aβ42 的摩尔比很高的情况下也是如此。在细胞中，Aβ42 与 Aβ42 结合，而可溶性重组肽的两种形式则表现出纳摩尔结合亲和力。重要的是，Aβ42 强烈抑制 Aβ42 淀粉样纤维的形成，如通过检测淀粉样纤维的硫黄素 T 荧光和透射电子显微镜来证明。总的来说，我们提出了一种在细胞内外抑制 Aβ42 纤维形成的新方法。因此，应该评估 Aβ42 作为治疗 AD 的潜在治疗先导。
