Iron overload and oxidative stress participated in zinc oxide nanoparticles-induced blood-brain barrier dysfunction

Since zinc oxide nanoparticles (ZnO-NPs) are widely used, concerns about their potential human health effects are growing. Although ZnO-NPs, due to their nano-size, can cross the blood-brain barrier (BBB) and affect brain function, the potential risk of ZnO-NPs in brain endothelial cells, the major components of the BBB, is largely unknown. In brain endothelial cells (bEnd.3 cells), ZnO-NPs were exposed for 9 h to evaluate the brain endothelial dysfunction and BBB disruption. ZnO-NPs were deposited in the lysosome and promoted ferroptosis in bEnd.3 cells. Increased oxidative stress led to lysosomal dysfunction and cytotoxicity in bEnd cells treated with ZnO-NPs.3 cells. ZnO-NPs induced dysregulated autophagy flux and hyperpermeability via intracellular iron overload in bEnd.3 cells. We developed a putative adverse outcome pathway (AOP) to understand the effects of ZnO-NPs on the function of brain endothelial cells. Our study will help clarify the potential impact and toxicity of ZnO-NPs on the brain endothelium and the BBB.