Data mining of gene expression profiles of acute kidney injury (AKI) and acute lung injury (ALI) in mice was conducted based on bioinformatics analysis in order to study the relationship between AKI and ALI.

AKI and ALI gene expression profiles were downloaded from the Gene Expression Omnibus (GEO) database. After the batch effect was removed, difference analysis was performed. Enrichment analysis of differentially expressed genes (DEGs) in AKI and ALI with the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The STRING database was used to build a protein-protein interaction (PPI) network in which the core modules and hub genes were detected. The best hub genes were obtained by using six algorithms from Cytoscape′s plugin cytoHubba. Finally, Immune cell infiltration analysis was conducted to analyze the relationship between optimal hub genes and immune cells.

A total of 114 overlapping DEGs were screened out at 4-6 h after establishment of AKI and ALI. A total of 62 overlapping DEGs were screened out at 24 h after establishment of AKI and ALI. The GO and KEGG enrichment analysis suggested that the overlapping DEGs were mainly related to immune and inflammatory signaling pathways. Finally, five optimal hub genes including IL-6, IL-1β, CCL2, TLR2, and CXCL10 were screened out at 4-6 h after establishment of AKI and ALI. Besides, five optimal hub genes including IL-6, IL-1β, TNF, TLR2, and CXCL10 were also screened out at 24 h after establishment of AKI and ALI. At 4-6 h after establishment of AKI, the hub genes expression were positively correlated with neutrophils and M1 macrophages, but negatively correlated with memory CD4⁺ T cells and memory CD8⁺ T cells. At 4-6 h after establishment of ALI, expression of the hub genes were positively correlated with dendritic cells and monocytes, but negatively correlated with immature dendritic cells and eosinophils. At 24 h after establishment of AKI, expression of the hub genes were positively correlated with neutrophils, and negatively correlated with naive B cells and regulatory T cells. At 24 h after establishment of ALI, expression of the hub genes were positively correlated with M1 and M2 macrophages and neutrophils, but negatively correlated with naive CD8⁺ T cells and eosinophils.

The AKI and ALI models showed similar hub genes and signaling pathways at 4-6 h and 24 h after models establishemnt. The molecular mechanisms of the two diseases were closely related, and further studies are needed to further explore the potential therapeutic targets.