Identification of microRNAs in acute respiratory distress syndrome based on microRNA expression profile in rats.

Acute respiratory distress syndrome (ARDS) remains a severe disease associated with an ~40% mortality rate and as many as 200,000 new cases annually. MicroRNAs (miRNAs) have important roles in gene regulation and cancer development. The present study aimed to identify the potential roles of miRNAs in the pathogenesis and progression of ARDS. The miRNA expression profile of the GSE57223 dataset was downloaded from the Gene Expression Omnibus database. Following data normalization, differentially expressed miRNAs were identified using the t‑test method. The miRWalk database was searched to predict target genes of the identified miRNAs and then a miRNA‑miRNA network with co‑regulated target genes was constructed. Additionally, Gene Ontology (GO) analysis was performed for the target genes and a miRNA‑miRNA functional synergistic network (MFSN) was established. GO and pathway analyses were performed for the co‑regulated target genes of significant miRNAs in MFSN. Additionally, a protein‑protein‑interaction network was constructed for these target genes. A total of 19 miRNAs were differentially expressed between ARDS and normal lung tissue were identified. The four downregulated rno‑let‑7 family members were detected to have numerous co‑regulated target genes and synergistic functions. Additionally, the target genes of the four miRNAs were significantly enriched the biological processes of wounding and inflammatory response. Additionally, interleukin (IL)‑6 was identified as a hub protein with a high degree. The four downregulated rno‑let‑7 miRNAs may be involved in the inflammatory process in the pathogenesis and progression of ARDS, via the synergistic regulation of their target genes, such as IL‑6. However, additional experimental validation is required.