Knockdown of JMJD3 ameliorates cigarette smoke extract-triggered bronchial epithelial cell injury via ACSL4-dependent ferroptosis

Chronic obstructive pulmonary disease (COPD), a heterogeneity of chronic respiratory disease pattern, presents considerable prevalence and mortality. We aimed to explore the role and mechanisms of Jumonji domain-containing protein-3 (JMJD3) in COPD. The viability and JMJD3 expression in human bronchial epithelial cell line BEAS-2B were respectively assayed by CCK-8 assay and Western blot following stepwise exposure to increasing concentrations of cigarette smoke extract (CSE). After JMJD3 was silenced and acyl-CoA synthetase long-chain family member 4 (ACSL4) was overexpressed in CSE-treated BEAS-2B cells, cell viability, cytotoxicity, oxidative stress and total iron level were estimated using kits. ELISA estimated inflammatory levels. DCFH-DA probe and BODIPY 581/591 C11 probe were exposed to assess ROS production and lipid peroxidation. Western blot tested the expressions of ferroptosis-associated proteins. Besides, H3K27me3 and ACSL4 expressions were tested by Western blot and immunofluorescence staining. In CSE-induced BEAS-2B cells, JMJD3 expression was increased and deletion of JMJD3 improved cell viability, reduced LDH release, mitigated inflammation, oxidative stress and inhibited ferroptosis. Moreover, JMJD3 interference raised H3K27me3 expression whereas lessened ACSL4 expression in CSE-treated BEAS-2B cells. CSE exposure reduced the abundance of ACSL4 in H3K27me3 antibody. Further ACSL4 elevation reversed the impacts of JMJD3 silencing on the damage of CSE-induced BEAS-2B cells. Collectively, JMJD3 depletion might suppress ferroptosis mediated by ACSL4 to alleviate CSE-triggered inflammation and oxidative stress in BEAS-2B cells.