Evaluation of atmospheric pollutant NO2 on respiratory toxicity associated with ferroptosis in vitro and in vivo

Air pollution is indeed a pressing global public health issue that warrants comprehensive attention. Our research, conducted from 2015 to 2019, revealed significant air pollution in Guangzhou, with particularly high levels of NO₂. Employing air-liquid interface incubation technique to develop in vitro models, we discovered that exposure to 10 ppm NO₂ could lead to cell death, oxidative stress, inflammation, and DNA damage. Concurrently, we utilized a dynamic oral-nasal inhalation exposure system to establish acute animal models, observing that short-term NO₂ exposure in mice resulted in pathological lung damage, oxidative stress, inflammation, and DNA damage. Mechanistically, transcriptome sequencing revealed an enrichment of ferroptosis in cells exposed to NO₂. Mitochondrial damage, iron accumulation, and the differential expression of genes related to ferroptosis, as observed in both in vitro and in vivo studies, collectively suggest that ferroptosis contributed to NO₂-induced toxicity. Furthermore, the silencing of STEAP3, a gene significantly associated with ferroptosis, mitigated the effects of NO₂ exposure. Collectively, our findings indicated that elevated NO₂ levels in Guangzhou and NO₂-induced toxicity may be linked to STEAP3-mediated ferroptosis. This discovery is anticipated to offer novel perspectives on the hazards of NO₂.