Graphene Oxide Nanocolloids Induce Autophagy-Lysosome Dysfunction in Mouse Embryonic Stem Cells

: In this study, we aimed to investigate the in vitro impacts and mechanisms of graphene oxide (GO) nanocolloids on autophagy in mouse embryonic stem cells (mESCs). Our results showed that GO nanocolloids treatment induced autophagosome accumulation in mESCs. In addition, we found that this effect was mediated by the blockade of autophagic flux rather than autophagic induction, as evidenced by the elevated autophagic substrate SQSTM1/p62 level and LC3B turn over. Moreover, our data further revealed that GO nanocolloids disrupted autophagic flux by impairing lysosomal function, including lysosomal alkalinization and lysosome membrane permeabilization. These results indicate that GO nanocolloids can block autophagic flux in mESCs via autophagy-lysosome dysfunction. Our findings may reveal the putative mechanism of GO nanocolloids-modulated autophagy and provide experimental evidence for the importance of future safety evaluation of nanomaterials.