Tang Xintong, Gao Guanbin, Zhang Ting, Li Jianhang, Yu Meng, He Meng, Sun Taolei
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China.
Nanoscale. 2020 Sep 28;12(36):18834-18843. doi: 10.1039/d0nr03877f. Epub 2020 Sep 8.
The misfolding and abnormal amyloid fibrillation of proteins/peptides are associated with more than 20 human diseases. Although dozens of nanoparticles have been investigated for the inhibition effect on the misfolding and fibrillation of pathogenesis-related proteins/peptides, there are few reports on charge effects of nano inhibitors on amyloid fibrillation. Herein, same-sized gold nanoclusters modified with 2-aminoethanethiol hydrochloride (CSH-AuNCs, positively charged in pH 7.4) or 3-mercaptopropionic acid (MPA-AuNCs, negatively charged in pH 7.4) were synthesized and adopted as models to explore the charge effect of nano inhibitors on amylin fibrillation at the nano-bio interface. ThT fluorescence kinetics analysis, AFM images and circular dichroism (CD) spectra showed that electropositive CSH-AuNCs inhibited the misfolding and fibrillation of amylin in a dosage-dependent manner, but electronegative MPA-AuNCs accelerated the misfolding and fibrillation of amylin in a dosage-dependent manner. Moreover, the theoretical and experimental results revealed the interaction mechanism between amylin and ligands of AuNCs at the nano-bio interfaces. Electropositive CSH-AuNCs could be bound to the main nucleating region of amylin via hydrogen bonding and endowed the nanocomplex with more positive net charges (amylin monomer with a positive +26.23 ± 0.80 mV zeta potential), which would inhibit the misfolding and aggregation of amylin via electrostatic repulsion and steric hindrance. In contrast, electronegative MPA-AuNCs could absorb electropositive amylin via strong electrostatic attractions, which accelerated the fibrillation process of amylin via enhancing local concentrations. Moreover, cell experiments showed that both the charged AuNCs had good biocompatibility and electronegetive MPA-AuNCs showed a better protective effect in the amylin-induced cell model than electropositive CSH-AuNCs. These results provide an insight into structure-based nanodrug design for protein conformational diseases.
蛋白质/肽的错误折叠和异常淀粉样纤维化与20多种人类疾病相关。尽管已经研究了数十种纳米颗粒对致病相关蛋白质/肽的错误折叠和纤维化的抑制作用，但关于纳米抑制剂对淀粉样纤维化的电荷效应的报道却很少。在此，合成了用盐酸2-氨基乙硫醇（CSH-AuNCs，在pH 7.4时带正电）或3-巯基丙酸（MPA-AuNCs，在pH 7.4时带负电）修饰的相同尺寸的金纳米团簇，并将其用作模型，以探索纳米抑制剂在纳米-生物界面上对胰淀素纤维化的电荷效应。硫黄素T荧光动力学分析、原子力显微镜图像和圆二色性（CD）光谱表明，带正电的CSH-AuNCs以剂量依赖的方式抑制胰淀素的错误折叠和纤维化，而带负电的MPA-AuNCs以剂量依赖的方式加速胰淀素的错误折叠和纤维化。此外，理论和实验结果揭示了胰淀素与金纳米团簇配体在纳米-生物界面上的相互作用机制。带正电的CSH-AuNCs可通过氢键与胰淀素的主要成核区域结合，并赋予纳米复合物更多的正净电荷（胰淀素单体的zeta电位为+26.23±0.80 mV），这将通过静电排斥和空间位阻抑制胰淀素的错误折叠和聚集。相反，带负电的MPA-AuNCs可通过强静电吸引吸附带正电的胰淀素，这通过提高局部浓度加速了胰淀素的纤维化过程。此外，细胞实验表明，带电的金纳米团簇都具有良好的生物相容性，并且带负电的MPA-AuNCs在胰淀素诱导的细胞模型中比带正电的CSH-AuNCs表现出更好的保护作用。这些结果为基于结构的蛋白质构象疾病纳米药物设计提供了见解。
