Screening of potential key ferroptosis-related genes in sepsis

Sepsis leads to multiple organ dysfunction caused by a dysregulated host response to infection with a high incidence and mortality. The effect of ferroptosis on the development of sepsis remains unclear. In this study, we aimed to identify the key ferroptosis-related genes involved in sepsis and further explore the potential biological functions of these ferroptosis-related genes in sepsis using bioinformatics analysis.

The GSE13904 (from children) and GSE28750 (from adults) datasets were downloaded from the Gene Expression Omnibus (GEO). The ferroptosis-related genes were obtained from the FerrDb database. The ferroptosis-related differentially expressed genes (DEGs) were screened by the limma R package. The DAVID online database or clusterProfiler R package was used for the functional enrichment analysis. Then, the STRING database was used to predict the interactions of proteins, and the CytoHubba plugin of Cytoscape was used to confirm key clustering modules. Then, the miRNAs and lncRNAs associated with the key clustering modules were predicted by miRWalk 2.0 and LncBase v.2 respectively. Finally, we generated a cecal ligation and puncture (CLP) polymicrobial sepsis model in C57 male mice and examined the expression of the mRNAs and noncoding RNAs of interest in peripheral blood leukocytes by PCR during the acute inflammation phase.

In total, 34 ferroptosis-related DEGs were identified in both adult and pediatric septic patients. These ferroptosis-related DEGs were mainly enriched in inflammatory pathways. Then, a significant clustering module containing eight genes was identified. Among them, the following five genes were closely associated with the MAPK signaling pathway: MAPK14, MAPK8, DUSP1, MAP3K5 and MAPK1. Then, crucial miRNAs and lncRNAs associated with biomarker MAPK-related genes were also identified. In particular, let-7b-5p and NEAT1 were selected as noncoding RNAs of interest because of their correlation with ferroptosis in previous studies. Finally, we examined the mRNAs, miRNAs and lncRNAs of interest using CLP-induced sepsis in peripheral blood leukocytes of mice. The results showed that MAPK14, MAPK8, MAP3K5, MAPK1 and NEAT1 were upregulated, while DUSP1 and let-7b-5p were downregulated in the CLP group compared with the sham group.

The MAPK signaling pathway may play a key role in regulating ferroptosis during sepsis. This study provides a valuable resource for future studies investigating the mechanism of MAPK-related ferroptosis in sepsis.