Liu Hongchen, Yu Linling, Dong Xiaoyan, Sun Yan
Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
J Colloid Interface Sci. 2017 Apr 1;491:305-312. doi: 10.1016/j.jcis.2016.12.038. Epub 2016 Dec 19.
Fibrillogenesis of amyloid β-protein (Aβ) in human brain has been implicated as the main cause of Alzheimer's disease. A few small molecules from natural sources have been discovered for their inhibition effects on Aβ fibrillation, of which (-)-epigallocatechin-3-gallate (EGCG) is one of the most broadly investigated compounds for its potent inhibitory activity. However, in vivo applicability of the inhibitors is largely limited by their low transmembrane efficiency. Hence, it is of great significance to develop inhibition systems that function at low concentrations. In this work, a dual-inhibitor system containing EGCG and negatively charged polymeric nanoparticles (NP10), which was also demonstrated effective on the inhibition of Aβ aggregation, was developed and comprehensively studied by extensive biophysical and biological assays. It was found that the dual-inhibitor system at low concentrations was more effective on the inhibition and detoxification of Aβ (Aβ and Aβ) fibrillation than the additive effects of these two agents working individually. Namely, there was a synergistic effect of the two inhibitors. The synergism factor reached 1.25 with 5μM EGCG and 5μg/mL NP10. Kinetic studies with Aβ revealed that the two inhibitors functioned in different Aβ assembling stages: NP10 mainly inhibited primary nucleation, while EGCG suppressed fibril elongation and changed the fibril structure to make it show less seeding activities in the secondary nucleation. NP10 might also help EGCG binding to Aβ, leading to its enhanced inhibitory effects on fibril elongation and secondary nucleation. The synergistic effect observed in the dual-inhibitor system offered new insight into the development of potent inhibitor systems against amyloid neurotoxicity.
人脑淀粉样β蛋白（Aβ）的原纤维形成被认为是阿尔茨海默病的主要病因。人们已经发现一些天然来源的小分子对Aβ原纤维形成具有抑制作用，其中（-）-表没食子儿茶素-3-没食子酸酯（EGCG）因其强大的抑制活性而成为研究最为广泛的化合物之一。然而，这些抑制剂在体内的适用性很大程度上受到其低跨膜效率的限制。因此，开发在低浓度下起作用的抑制系统具有重要意义。在这项工作中，开发了一种包含EGCG和带负电荷的聚合物纳米颗粒（NP10）的双抑制剂系统，该系统对Aβ聚集的抑制作用也得到了证实，并通过广泛的生物物理和生物学测定进行了全面研究。结果发现，低浓度的双抑制剂系统对Aβ（Aβ和Aβ）原纤维形成的抑制和解毒作用比这两种药物单独作用的加和效应更有效。也就是说，这两种抑制剂存在协同效应。5μM EGCG和5μg/mL NP10时协同因子达到1.25。对Aβ的动力学研究表明，这两种抑制剂在不同的Aβ组装阶段起作用：NP10主要抑制初级成核，而EGCG抑制原纤维伸长并改变原纤维结构，使其在二次成核中显示出较低的种子活性。NP10还可能有助于EGCG与Aβ结合，从而增强其对原纤维伸长和二次成核的抑制作用。双抑制剂系统中观察到的协同效应为开发有效的抗淀粉样神经毒性抑制剂系统提供了新的见解。
