MAPK14 drives Ferroptosis and immune dysfunction in pediatric Sepsis-induced acute lung injury.

OBJECTIVE

Sepsis-induced acute lung injury (ALI) is driven by inflammation, oxidative stress, and immune suppression. MAPK14 (p38α) plays a role in ferroptosis and immune regulation, but its specific function in pediatric sepsis remains unclear. Therefore, our study aimed to explore the role and underlying mechanism of MAPK14 in pediatric sepsis.

METHODS

Bioinformatics analysis of GSE26440 and FerrDb identified ferroptosis-related genes in pediatric sepsis. STRING database was used to predict the proteins associated with MAPK14. MAPK14 expression in whole blood samples, LPS-treated MLE-12 cells, and a CLP mouse model was detected by qRT-PCR and western blot. Ferroptosis was assessed by measuring MDA, GSH, and Fe2+ levels, while ROS accumulation was analyzed using DCFH-DA staining and DHE staining. A cycloheximide (CHX) assay was performed to assess TTP53 protein stability. MPO immunohistochemistry and PD-L1 immunofluorescence assessed neutrophil infiltration, and flow cytometry evaluated neutrophil apoptosis.

RESULTS

Bioinformatics analysis of GSE26440 and FerrDb identified MAPK14 as a ferroptosis-related gene in pediatric sepsis. MAPK14 expression was upregulated in sepsis patient samples, LPS-treated MLE-12 cells and CLP mouse lung tissues. Overexpression of MAPK14 led to increased MDA and Fe2+ levels, reduced GSH, and elevated ROS fluorescence intensity, confirming its role in promoting ferroptosis. Mechanistically, MAPK14 upregulated TTP53, which in turn suppressed SLC7A11 and GPX4, further driving ferroptosis. MAPK14 overexpression stabilized TTP53 and enhanced its activity. Additionally, MAPK14 enhanced MPO and PD-L1 expression to promote neutrophil infiltration and immune suppression. Additionally, MAPK14 overexpression inhibited neutrophil apoptosis, promoted neutrophil infiltration and enhanced immune suppression.

CONCLUSION

MAPK14 drives ferroptosis via the TTP53/SLC7A11/GPX4 pathway and exacerbates immune suppression by promoting neutrophil infiltration.