NCOA4-mediated ferritinophagy regulates AgNP-induced ferroptosis in lung cells

Silver nanoparticles (AgNPs) possess unique properties and strong antimicrobial effects, making them valuable for industrial and medical uses. However, concerns about their health risks are increasing, particularly regarding lung toxicity as studies show the respiratory system is especially vulnerable to AgNP exposure. Emerging evidence implicates ferroptosis in AgNPs-induced lung injury, but its molecular mechanisms are poorly understood. Using in vitro and in vivo models, we examined AgNPs-triggered ferroptosis, specifically focusing on NCOA4-regulated ferritinophagy. Our results demonstrated that AgNPs induced dose-dependent cytotoxicity and lung damage, triggering iron dysregulation via NCOA4-mediated ferritinophagy and subsequent iron overload. Excessive free iron triggered subsequent glutathione (GSH) depletion, elevated reactive oxygen species (ROS) and malondialdehyde (MDA) levels, dysregulated ferroptosis-related proteins, and lipid peroxidation, collectively initiating a ferroptosis cascade. These effects were substantially reversed by ferroptosis inhibitors (Fer-1 and DFO). Further intervention using NCOA4 siRNA and autophagy modulators (3-MA and Rapa) revealed that reduced NCOA4 expression and autophagy inhibition significantly attenuated AgNPs-induced ferroptosis. These findings suggest ferroptosis as a potential mechanism underlying AgNPs-induced pulmonary toxicity, with NCOA4-mediated ferritinophagy serving as a crucial promotive pathway. This study provides novel mechanistic insights into AgNPs-induced lung toxicity and lays foundation for developing preventive strategies.