The Role of Ferroptosis in Bronchoalveolar Epithelial Cell Injury Induced by Cigarette Smoke Extract

Background: Cigarette smoking is a major risk factor for bronchoalveolar epithelial cell (BAEC) injury. Understanding the relevant pathogenesis is important for the treatment of cigarette smoke-related chronic airway diseases such as chronic obstructive pulmonary disease. Methods: In this study, BAECs were cultured in 5% cigarette smoke extract (CSE) or regular culture medium for 24 h. Differentially expressed genes (DEGs) were detected by next-generation RNA sequencing (RNA-seq) and validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Bioinformatic analysis was performed on DEGs. Co-treated BAECs with 5% CSE and the ferroptosis inhibitor, ferrostatin-1 was applied to observe the role of ferroptosis. Results: In the CSE group, 210 upregulated genes and 159 downregulated genes were identified compared with the control group. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that the DEGs were related to oxidative stress and ferroptosis. Ferroptosis-related genes were further verified by qRT-PCR. The mRNA level of GPX4 decreased; the mRNA levels of ACSL4, FTH1 and SLC7A11 increased (p < 0.05). Pretreatment with the ferroptosis inhibitor ferrostatin-1 mitigated CSE-induced ROS accumulation and inflammatory mediator expression in BAECs (p < 0.05). Conclusion: CSE treatment altered ferroptosis-related gene expression patterns in cultured BAECs. Inhibition of ferroptosis reduced the inflammatory response of CSE-treated BAECs. These data provide a better understanding of the underlying molecular mechanisms of CSE-related lung injury.