An integrated deep sequencing analysis of microRNAs in transplanted corneas

Illumina Hiseq 2500 deep sequencing was used to screen for differentially expressed genes (DEGs) in matched pairs of isograft corneas and normal corneas, allograft corneas and isograft corneas. Our results showed that 22 miRNAs were significantly upregulated and 4 were significantly downregulated in the isograft group when compared with the control group (P < 0.01), while 17 miRNAs were significantly upregulated and 3 were significantly downregulated in the allograft group when compared with the isograft group (P < 0.01). Among the miRNAs with altered expression levels, miR-155-5p, miR-142-3p, miR-142-5p, and miR-223-3p displayed simultaneous changes in the above two comparisons. Potential target genes among the DEGs were predicted using target prediction software (TargetScan, Miranda, miRDB, and CLIP), and the overlay portion was analyzed using the Gene Ontology (GO) database and the Kyoto Encyclopedia of Genes and Genomes (KEGG). GO and KEGG analyses showed that the DEGs were mainly involved in metabolic pathways, cytokine secretion, and tumor immunity functions. An analysis of the interactions between DEG proteins (PPI analysis) and a MetaCore software analysis of 4 key DEGs revealed that the genes regulated by miR-155-5p played important roles in the miRNA-mRNA regulatory network. Furthermore, the MetaCore analysis identified C/EBP beta, p53, and sp1 as key transcription factors in that network. Our study identified transplanted corneas-specific miRNA in matched pairs of isograft corneas and normal corneas, allograft corneas and isograft corneas. Furthermore, bioinformatics analysis of the key miRNA regulatory network revealed the molecular mechanisms, which suggests miRNAs may as new molecular targets for treating corneal injuries and corneal transplant rejection.