Identification and validation of autophagy-related genes in exogenous sepsis-induced acute respiratory distress syndrome

Objective: To analyze the differential expression of autophagy-related genes of sepsis-induced acute respiratory distress syndrome (ARDS) as potential markers for early diagnosis. Methods: Male Sprague-Dawley rats (aged 8 weeks) were selected and randomly divided into sepsis-induced ARDS group (n = 6) and a normal control group (n = 6). Lung tissue samples were collected for highthroughput sequencing using Illumina HiSeq sequencing platform in the paired-end sequencing mode. Differentially expressed genes (DEGs) were screened by DESeq. 2 software [vertical bar log2FC vertical bar >= 1 and p < .05] and autophagyrelated genes were identified using Mouse Genome Informatics. Coexpressed autophagy-related DEGs from these two datasets were filtered by construction of a Venn diagram. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed on these autophagy-related DEGs and a protein interaction network was constructed using STRING and Cytoscape software to identify hub genes, which were verified by real-time quantitative polymerase chain reaction (qRT-PCR). Results: A total of 42 autophagy-related DEGs (26 upregulated genes and 16 downregulated genes) were identified. The GO and KEGG pathway analyses showed enrichment in 969 biological processes (BPs), three cellular components (CCs), eight molecular functions (MFs) and 27 signaling pathways. The protein interaction (PPI) network revealed 42 node proteins and 75 interacting edges, with an average node degree of 3.52, and an average local clustering coefficient of 0.509. Among the top 10 hub genes with the RNA-Seq, six hub genes (Stat3, II10, Ifng, Hmox1, Hif1a, and Nod2) were validated by qRT-PCR (all p < .05). Conclusion: 42 potential autophagy-related genes associated with sepsis-induced ARDS lung injury were identified and six hub genes (Stat3, II10, Ifng, Hmox1, Hif1a, and Nod2) may affect the development of ARDS by regulating autophagy. These results expanded our understanding of ARDS and might be useful in treatment of exogenous sepsis-induced ARDS.