METTL14‐Mediated N6‐Methyladenosine Exacerbates Acute Lung Injury via USP30/NCOA4‐Dependent Ferroptosis

ABSTRACT Ischemia/reperfusion (I/R)‐induced acute lung injury (ALI) is a severe clinical syndrome characterized by alveolar epithelial damage, oxidative stress, and acute respiratory failure, but the epitranscriptomic mechanisms linking N6‐methyladenosine (m6A) modification to ferroptosis remain unclear. Clinical profiling of end‐stage acute respiratory distress syndrome (ARDS) patients showed hyperinflammation, reflected by elevated C‐reactive protein and procalcitonin, coagulopathy with abnormal D‐dimer levels, and severely impaired gas exchange. Reanalysis of a public murine single‐cell RNA sequencing dataset revealed enrichment of RNA methylation‐, ubiquitination‐, and ferroptosis‐related programs in injured lung epithelial cells. Integrated methylated RNA immunoprecipitation sequencing and RNA sequencing of I/R‐injured mouse lungs further identified methyltransferase‐like 14 (METTL14) and YTH N6‐methyladenosine RNA‐binding protein 1 (YTHDF1) as candidate m6A regulators. Human ARDS tissues and mouse I/R lungs confirmed increased METTL14, ubiquitin‐specific peptidase 30 (USP30), and nuclear receptor coactivator 4 (NCOA4) expression. Mechanistically, METTL14‐mediated m6A modification enhanced USP30 expression through YTHDF1 recognition, whereas USP30 stabilized NCOA4 by reducing K48‐linked polyubiquitination. Stabilized NCOA4 promoted ferritinophagy, Fe 2 + accumulation, lipid peroxidation, and epithelial ferroptosis. These findings identify a METTL14/YTHDF1‐USP30‐NCOA4 axis as a potential therapeutic target for ferroptosis‐driven I/R‐induced ALI.