Lysosomal deposition of copper oxide nanoparticles triggers HUVEC cells death.

The increasing use of copper oxide nanoparticles (CuONPs) has led to major concerns regarding both the predominant physicochemical properties and the potential toxic effects on the environment and human health. The objective of this study is to explore the possible mechanisms underlying the toxicity of CuONPs in vascular endothelial cells. We found that CuONPs induced the cell death in human umbilical vein endothelial cells (HUVECs) through a caspase-independent pathway. Our results also demonstrated that CuONPs were prevalently deposited within lysosomes. The lysosomal deposition of CuONPs led to lysosomal dysfunction, resulting in the impairment of autophagic flux and the accumulation of undegraded autophagosomes. Nevertheless, blockage of the lysosomal deposition of CuONPs could significantly attenuate HUVEC cell death. Interestingly, we found that the inhibition of lysosomal deposition of CuONPs reduced the release of Cu ions, which has been considered as the crucial factor for the toxicity of CuONPs. In summary, our results indicate that the lysosomal deposition of CuONPs (along with the enhanced release of Cu ions form CuONPs) triggers CuONPs-induced HUVEC cell death. Our findings provide an insight into the mechanism of toxicity to the cardiovascular system induced by toxic metal oxide nanoparticles exposure.