Li Meng, Zhao Andong, Ren Jinsong, Qu Xiaogang
Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, Jilin 130022, China.
University of Chinese Academy of Sciences , Beijing 100039, China.
ACS Chem Neurosci. 2017 Jun 21;8(6):1299-1304. doi: 10.1021/acschemneuro.6b00436. Epub 2017 Mar 17.
Formation of amyloid fibrils by amyloid-β peptide (Aβ) is an important step in Alzheimer's disease (AD) progression. Screening and designing of new molecules which can monitor the amyloidosis process especially in cells are diagnostically and therapeutically important. Utilizing Thioflavin T (ThT), the commonly used amyloid dye, is the most standardized way to monitor amyloid. However, with the green fluorescence emission and small Stokes shift, the fluorescence of ThT can overlap with that arising from other intrinsic fluorescent components in the cells, making it not suitable for detection of protein aggregates in vivo. Therefore, it is urgent for developing amyloid probes with large Stokes shifts and red-shifted fluorescence emission to detect Aβ aggregates in cells. In this report, we found that N-methyl mesoporphyrin IX (NMM), a widely used G-quadruplex DNA specific fluorescent binder, can be an efficient probe for monitoring Aβ fibrillation in living cells. NMM is nonfluorescent in aqueous solution or monomeric Aβ environments. However, through stacking with the Aβ assemblies, NMM emits strong fluorescence. Furthermore, the large Stokes shift and stable photoluminescence make it an ideal probe for detecting Aβ aggregates in highly fluorescent environments and cell culture. Our results provide a new sight to design and screen new reagents for monitoring the diseases associated with protein conformational disorders.
淀粉样β肽（Aβ）形成淀粉样纤维是阿尔茨海默病（AD）进展中的重要一步。筛选和设计能够监测淀粉样变性过程，尤其是在细胞内监测该过程的新分子，在诊断和治疗方面都具有重要意义。使用常用的淀粉样染料硫黄素T（ThT）是监测淀粉样蛋白的最标准化方法。然而，由于其绿色荧光发射和小的斯托克斯位移，ThT的荧光可能与细胞中其他固有荧光成分产生的荧光重叠，使其不适用于体内蛋白质聚集体的检测。因此，迫切需要开发具有大斯托克斯位移和红移荧光发射的淀粉样探针，以检测细胞中的Aβ聚集体。在本报告中，我们发现N-甲基中卟啉IX（NMM），一种广泛使用的G-四链体DNA特异性荧光结合剂，可作为监测活细胞中Aβ纤维化的有效探针。NMM在水溶液或单体Aβ环境中无荧光。然而，通过与Aβ聚集体堆积，NMM发出强烈荧光。此外，大的斯托克斯位移和稳定的光致发光使其成为在高荧光环境和细胞培养中检测Aβ聚集体的理想探针。我们的结果为设计和筛选用于监测与蛋白质构象紊乱相关疾病的新试剂提供了新视角。
