FIGURE 5.

The knockout of METTL3 attenuates sepsis‐induced acute lung injury (SI‐ALI). (A and B) Real‐time quantitative PCR (RT‐qPCR) was used to evaluate METTL3 and glutathione‐peroxidase 4 (GPX4) mRNA levels in the si‐METTL3, OE‐METTL3 and OE‐METTL3‐Mut groups. (C) GPX4 protein levels in si‐NC, METTL3‐Mut, si‐METTL3 and METTL3‐WT groups. (D) Cell Counting Kit‐8 (CCK‐8) assay evaluated human alveolar epithelial cells (HPAEpiC) cell viability (n = 6 in each group). (E) An iron assay kit was used to measure ferrous iron (Fe²⁺) levels (n = 6 in each group). (F) A lipid peroxidation assay kit measured the MDA levels (n = 6 in each group). (G) The level of reactive oxygen species (ROS) was detected by DCF‐DA assay (n = 6 in each group). (H) Lung tissues from wild‐type (WT) and METTL3 CKO mice with SI‐ALI. (I) Images from haematoxylin and eosin (H&E) staining of lung tissues evaluated the degree of lung damage and inflammation. (J) Images from Masson staining of lung tissues evaluated the degree of lung fibrosis. (K) Scanning electron microscope evaluated the neutrophil extracellular trap (NET) level of NETs from WT and METTL3 CKO mice in the sham and SI‐ALI groups. (L) Immunofluorescence (IF) analysed the level of NETs from WT and METTL3 CKO mice in sham and SI‐ALI groups. (M) The degree of lung damage was evaluated by wet/dry ratio (n = 6 in each group). (N) Cell counting in mouse models (n = 6 in each group) measured total cells in bronchoalveolar lavage fluid (BALF). (O–Q) The degree of systemic inflammation was evaluated by tumour necrosis factor (TNF)‐α, TNF‐β and IL‐1α (n = 6 in each group). (R) The plasma cfDNA was detected in WT and METTL3 CKO mice in sham and SI‐ALI groups (n = 6 in each group). (N–P) ^* p < .05; ^** p < .01. ^#SI‐ALI versus Sham (two‐way analysis of variance [ANOVA] with Tukey's correction).