纳米金棒诱导A549细胞产生自噬的机制研究

摘要

Although gold nanorods ( AuNRs) have been widely used in biomedicine field due to their many special properties, their potential biological risks are still controversial. In this study, the author investigated the molecular mechanism of autophagy induced by AuNRs in A549 cells using laser scanning confocal microscopy, western blotting and other molecular biological methods from the perspective of cellular oxidative stress. The results showed that A549 cells treated with 4μg·mL-1 of AuNRs for 6 hours could increase the expression of autophagy marker protein LC3 - II and induce LC3 protein transferred from the nucleus to the cytoplasm which promote the formation of autophagy vesicles. Further studies showed that AuNRs can reduce the mitochondrial membrane potential, ATP content, UCP2 protein expression level, cell antioxidant capacity and increase ROS accumulation in A549 cells, which maybe eventually lead to autophagy. 10 mmol·L-1 antioxidant NAC could reverse the changes of mitochondria, cell function and inhibit the occurrence of autophagy. This study provided a strong experimental evidence for the further understanding of their biological risks and possible mechanisms.%纳米金棒(AuNRs)具有众多独特的属性,已广泛运用于生物医学领域,但其是否具有潜在的生物危害尚有争议.作者运用了激光扫描共聚焦显微镜技术、western blotting技术和其他分子生物学方法从细胞氧化应激的角度探讨了AuNRs诱导A549细胞产生自噬的分子机制.研究结果表明,4μg·mL-1的AuNRs处理6 h能够诱导A549细胞自噬标志蛋白LC3-Ⅱ表达增加,LC3蛋白从细胞核转移至细胞质并形成自噬小泡.进一步研究发现,AuNRs能够降低A549细胞线粒体膜电位、ATP含量、UCP2蛋白表达水平以及细胞抗氧化能力并导致活性氧蓄积,后者可能最终引起细胞产生自噬.而10 mmol·L-1抗氧化剂NAC能够逆转上述线粒体及细胞功能的改变,并抑制自噬的发生.这一研究为深入认识其生物危害及可能机制提供了有力的实验证据.