METTL14/IGF2BP1 m ⁶ A axis promotes pyroptosis in <i>Streptococcus pneumoniae</i> -induced pneumonia by regulating NEK7 mRNA stability

<i>Streptococcus pneumoniae</i> (<i>S. pneumoniae</i>) infection induces pyroptosis in human pulmonary artery epithelial cells (HPAEpiCs), which contributes to pneumonia pathogenesis. We aimed to investigate the regulatory role of N6-methyladenosine (m⁶A) modification mediated by methyltransferase-like (METTL) 14 in this process and elucidate the underlying molecular mechanisms. HPAEpiCs were infected with <i>S. pneumoniae</i>. Cell viability was assessed using the cell counting kit-8 assay, while cytokine concentrations were measured by enzyme-linked immunosorbent assay. Pyroptosis levels were analyzed through flow cytometry and Western blot for pyroptotic protein expression. Gene expression profiles, protein-RNA interactions, and m⁶A methylation sites were characterized by quantitative reverse transcription-polymerase chain reaction, RNA immunoprecipitation, and dual-luciferase reporter assays. <i>In vivo</i> experiments involved intranasal administration of <i>S. pneumoniae</i> in mice to evaluate pulmonary pathological changes. <i>S. pneumoniae</i> D39<i>-</i>infected HPAEpiCs exhibited enhanced pyroptosis and adhesive/invasive capabilities, accompanied by elevated m⁶A modification mediated by METTL14. In addition, METTL14 inhibition suppressed pyroptosis and adhesive/invasive capabilities and ameliorated <i>S. pneumoniae</i> D39<i>-</i>induced lung injury. Notably, NEK7 overexpression reversed the pyroptosis reduction caused by METTL14 knockout. Mechanistically, the METTL14/insulin-like growth factor 2 mRNA-binding proteins (IGF2BP)1 m⁶A regulatory axis modulated NEK7 mRNA stability through m⁶A-dependent post-transcriptional regulation. The METTL14/IGF2BP1 m⁶A regulatory axis promoted <i>S. pneumoniae</i> D39<i>-</i>induced pyroptosis by stabilizing NEK7 mRNA transcripts. Targeting this m⁶A regulatory pathway represents a potential therapeutic strategy for managing <i>S. pneumoniae</i> D39<i>-</i>induced pneumonia.