LC3B-regulated autophagy mitigates zinc oxide nanoparticle-induced epithelial cell dysfunction and acute lung injury

Zinc oxide nanoparticles (ZnONPs) are widely utilized across various industries, raising concerns about their potential toxicity, especially in the respiratory system. This study explores the role of autophagy, regulated by microtubule-associated protein 1A/1B-light chain 3B (LC3B), in ZnONPs-induced toxicity using both in vivo (LC3B knockout mice) and in vitro (BEAS-2B cells) models. Our findings demonstrate that LC3B-regulated autophagy mitigates ZnONPs-induced epithelial cell dysfunction and acute lung injury. In the absence of LC3B, oxidative stress, inflammation, and intracellular zinc accumulation are exacerbated, resulting in mitochondrial dysfunction and epithelial cell death. In vitro, LC3B knockdown disrupted zinc ion transporter expression and impaired mitophagic flux in BEAS-2B cells. Treatment with zinc ion chelators alleviated these toxic effects, confirming that free zinc ions play a critical role in driving ZnONPs toxicity. These findings highlight that targeting autophagy and maintaining zinc homeostasis could offer therapeutic strategies to reduce ZnONPs-induced lung damage.