Zinc oxide nanoparticles (ZnONPs) are widely used in food, cosmetic, and biomedical fields, raising concerns about their potential neurotoxicity. However, the mechanisms underlying ZnONPs-induced brain injury remain incompletely understood, particularly regarding the role of iron-dependent cell death pathways. In this study, ZnONPs were characterized using transmission electron microscopy and dynamic light scattering. ICR mice and mouse hippocampal neuron HT22 cells were exposed to ZnONPs to evaluate histopathological injury, cytotoxicity, iron metabolism, oxidative stress, lipid peroxidation, autophagy, and ferroptosis. Our results show that ZnONPs induce dose-dependent neuronal injury in mouse brain tissue and reduce HT22 cell viability. ZnONPs promote Feaccumulation by increasing nuclear receptor coactivator 4 (NCOA4) expression, thereby exacerbating lipid peroxidation and reactive oxygen species (ROS) generation, while simultaneously depleting glutathione (GSH) and suppressing glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) expression, accompanied by mitochondrial dysfunction. Iron chelation with deferoxamine (DFO) significantly alleviated these effects. ZnONPs also induce autophagosome accumulation and impair autophagic flux, which is associated with enhanced ferroptotic signaling. Pharmacological inhibition of autophagy using 3-methyladenine (3-MA) restored iron homeostasis, antioxidant capacity, and mitochondrial function. This study demonstrates that ZnONPs trigger ferroptosis through NCOA4-dependent ferritinophagy and maladaptive autophagy, leading to iron overload, oxidative lipid damage, and mitochondrial dysfunction, thereby inducing neurotoxicity. Targeting the autophagy-ferritinophagy-ferroptosis axis may provide a therapeutic strategy to mitigate ZnONPs-induced neurological injury. 2+
