Zinc Oxide Nanoparticles Induce Ferroptotic Neuronal Cell Death in vitro and in vivo.

Zinc oxide nanoparticles (ZnONPs) are one of the most important nanomaterials that are widely used in the food, cosmetic and medical industries. Humans are often exposed to ZnONPs via inhalation, and they may reach the brain where neurotoxic effects could occur via systemic distribution. However, the mechanisms underlying how ZnONPs produce neurotoxic effects in the brain remain unclear. In this study, we aimed to investigate the novel mechanism involved in ZnONPs-induced neurotoxicity. We demonstrated for the first time that pulmonary exposure to ZnONPs by intratracheal instillation could trigger ferroptosis, a new form of cell death, in the neuronal cells of mouse cerebral cortex. A similar phenomenon was also observed in cultured neuron-like PC-12 cell line. By using a specific inhibitor of ferroptosis ferrostatin-1 (Fer-1), our results showed that inhibition of ferroptosis by Fer-1 could significantly alleviate the ZnONPs-induced neuronal cell death both in vivo and in vitro. Mechanistic investigation revealed that ZnONPs selectively activated the JNK pathway and thus resulted in the ferroptotic phenotypes, JNK inhibitor SP600125 could reverse lipid peroxidation upregulation and ferroptotic cell death induced by ZnONPs in PC-12 cells. Taken together, this study not only demonstrates that pulmonary exposure of ZnONPs can induce JNK-involved ferroptotic cell death in mouse cortex and PC-12 cells, but also provides a clue that inhibition of ferroptosis by specific agents or drugs may serve as a feasible approach for reducing the untreatable neurotoxicity induced by ZnONPs.

Qin X ，Tang Q ，Jiang X ，Zhang J ，Wang B ，Liu X ，Zhang Y ，Zou Z ，Chen C ... -  《International Journal of Nanomedicine》

Ferritinophagy is involved in the zinc oxide nanoparticles-induced ferroptosis of vascular endothelial cells.

Qin X ，Zhang J ，Wang B ，Xu G ，Yang X ，Zou Z ，Yu C ... -  《-》

Molecular mechanisms of zinc oxide nanoparticles neurotoxicity.

Aschner M ，Skalny AV ，Lu R ，Martins AC ，Tsatsakis A ，Miroshnikov SA ，Santamaria A ，Tinkov AA ... -  《-》

Disruption of the lung-gut-brain axis is responsible for cortex damage induced by pulmonary exposure to zinc oxide nanoparticles.

Increasing evidence shows that gut microbiota is important for host health in response to metal nanomaterials exposure. However, the effect of gut microbiota on the cortex damage caused by pulmonary exposure to zinc oxide nanoparticles (ZnONPs) remains mainly unknown. In this study, a total of 48 adult C57BL/6J mice were intratracheally instilled with 0.6 mg/kg ZnONPs in the presence or absence of antibiotics (ABX) treatment. Besides, 24 mice were treated with or without fecal microbiota transplantation (FMT) after the intraperitoneal administration of ABX. Our results demonstrated for the first time that dysbiosis induced by ABX treatment significantly aggravated cortex damage induced by pulmonary exposure to ZnONPs. Such damage might highly occur through the induction of oxidative stress, manifested by the enhancement of antioxidative enzymes and products of lipid peroxidation. However, ferroptosis was not involved in this process. Interestingly, our data revealed that ABX treatment exacerbated the alterations of gut-brain peptides (including Sst, Sstr2, and Htr4) induced by ZnONPs in both gut and cortex tissues. Moreover, fecal microbiota transplantation (FMT) was able to alleviate cerebral cortex damage, oxidative stress, and alterations of gut-brain peptides induced by pulmonary exposure to ZnONPs. The results together indicate that pulmonary exposure to ZnONPs causes cerebral cortex damage possibly via the disruption of the lung-gut-brain axis. These findings not only propose valuable insights into the mechanism of ZnONPs neurotoxicity but also provide a potential therapeutic method against brain disorders induced by pulmonary exposure to ZnONPs. AVAILABILITY OF DATA AND MATERIALS: The datasets used and/or analyzed during the current study are available from the The corresponding author on reasonable request.

Zhang L ，Zhang Y ，Jiang X ，Mao L ，Xia Y ，Fan Y ，Li N ，Jiang Z ，Qin X ，Jiang Y ，Liu G ，Qiu F ，Zhang J ，Zou Z ，Chen C ... -  《-》

Ferroptosis is newly characterized form of neuronal cell death in response to arsenite exposure.

Ferroptosis is a novel iron-dependent form of cell death implicated in brain pathology. However, whether arsenite is an inducer of ferroptosis in the neuron remains completely unknown. In this study, the seven-week-old healthy C57BL/6 J male mice were treated with environmental related doses (0.5, 5 and 50 mg/L) of arsenite for 6 months via drinking water, and the ferroptosis-related indicators were further determined. Our results demonstrated for the first time that, arsenite exposure significantly reduced the number of neuron and caused the pathological changes of mitochondria in the cerebral cortex of mice. We further revealed that arsenite induced ferroptotic cell death in neuron by accumulation of reactive oxygen species and lipid peroxidation products, disruption of Fe2+ homeostasis, depletion of glutathione and adenosine triphosphate, inhibition of cysteine/glutamate antiporter, activation of mitogen-activated protein kinases and mitochondrial voltage-dependent anion channels pathways, up-regulation of endoplasmic reticulum stress, all of which were involved in the process of ferroptosis. These findings were also verified in the cultured PC-12 cells by using ferropotosis inhibitor, desferoxamine. Taken together, our results not only reveal a novel mechanism that chronic arsenite exposure may trigger the new form of cell death, ferroptosis, but also shed a new light on a potential clue for the intervention and prevention against arsenite-related neurodegenerative diseases.

Tang Q ，Bai L ，Zou Z ，Meng P ，Xia Y ，Cheng S ，Mu S ，Zhou J ，Wang X ，Qin X ，Cao X ，Jiang X ，Chen C ... -  《-》