Ferritinophagy is involved in the zinc oxide nanoparticles-induced ferroptosis of vascular endothelial cells
Creators: name: Qin, Xia
name: Zhang, Jun
name: Wang, Bin
name: Xu, Ge
name: Yang, Xi
name: Zou, Zhen
name: Yu, Chao
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biochemistry
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Cell Biology
subject: Genetics
subject: Molecular Biology
subject: Physiology
subject: Biotechnology
subject: Chemical Sciences not elsewhere classified
subject: Science Policy
subject: Immunology
subject: FOS: Clinical medicine
subject: Cancer
subject: Inorganic Chemistry
subject: FOS: Chemical sciences
subject: Hematology
subject: Infectious Diseases
subject: FOS: Health sciences

description: Zinc oxide nanoparticles (ZnONPs) hold great promise for biomedical applications. Previous studies have revealed that ZnONPs exposure can induce toxicity in endothelial cells, but the underlying mechanisms have not been fully elucidated. In this study, we report that ZnONPs can induce ferroptosis of both HUVECs and EA.hy926 cells, as evidenced by the elevation of intracellular iron levels, lipid peroxidation and cell death in a dose- and time-dependent manner. In addition, both the lipid reactive oxygen species (ROS) scavenger ferrostatin-1 and the iron chelator deferiprone attenuated ZnONPs-induced cell death. Intriguingly, we found that ZnONPs-induced ferroptosis is macroautophagy/autophagy-dependent, because the inhibition of autophagy with a pharmacological inhibitor or by <i>ATG5</i> gene knockout profoundly mitigated ZnONPs-induced ferroptosis. We further demonstrated that NCOA4 (nuclear receptor coactivator 4)-mediated ferritinophagy (autophagic degradation of the major intracellular iron storage protein ferritin) was required for the ferroptosis induced by ZnONPs, by showing that <i>NCOA4</i> knockdown can reduce the intracellular iron level and lipid peroxidation, and subsequently alleviate ZnONPs-induced cell death. Furthermore, we showed that ROS originating from mitochondria (mtROS) probably activated the AMPK-ULK1 axis to trigger ferritinophagy. Most importantly, pulmonary ZnONPs exposure caused vascular inflammation and ferritinophagy in mice, and ferrostatin-1 supplementation significantly reversed the vascular injury induced by pulmonary ZnONPs exposure. Overall, our study indicates that ferroptosis is a novel mechanism for ZnONPs-induced endothelial cytotoxicity, and that NCOA4-mediated ferritinophagy is required for ZnONPs-induced ferroptotic cell death. <b>Abbreviations:</b> 3-MA: 3-methyladenine; ACTB: Actin beta; AMPK: AMP-activated protein kinase; ATG: Autophagy-related; BafA1: Bafilomycin A1; CQ: Choloroquine; DFP: Deferiprone; FACS: Fluorescence-activated cell sorting; Fer-1: Ferrostatin-1; FTH1: Ferritin heavy chain 1; GPX4: Glutathione peroxidase 4; GSH: Glutathione; IREB2/IRP2: Iron responsive element binding protein 2; LIP: Labile iron pool; MAP1LC3B/LC3B: Microtubule associated protein 1 light chain 3 beta; MTOR: Mechanistic target of rapamycin kinase; NCOA4: Nuclear receptor coactivator 4; NFE2L2/NRF2: Nuclear factor, erythroid 2 like 2; PGSK: Phen Green™ SK; ROS: Reactive oxygen species; siRNA: Small interfering RNA; SQSTM1/p62: Sequestosome 1; TEM: Transmission electron microscopy; ULK1: Unc-51 like autophagy activating kinase 1; ZnONPs: Zinc oxide nanoparticles.