Identification of key microRNAs and target genes for the diagnosis of bone nonunion

A number of recent studies have highlighted the causes of bone nonunion (BN), however, the rate of BN incidence continues to rise and available therapeutic options to treat this condition remain limited. Thus, to prevent disease progression and improve patient prognosis, it is vital that BN, or the risk thereof, be accurately identified in a timely manner. In the present study, bioinformatics analyses were used to screen for the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) between patients with BN and those with bone union, using data from the Gene Expression Omnibus database. Furthermore, clinical samples were collected and analyzed by reverse transcription-quantitative PCR and western blotting. In vitro and in vivo experiments were carried out to confirm the relationship between BN and the DEGs of interest, in addition to being used to explore the underlying molecular mechanism of BN. Functional enrichment analysis of the downregulated DEGs revealed them to be enriched for genes associated with 'ECM-receptor interactions', 'focal adhesion', 'and the calcium signaling pathway'. When comparing DEM target genes with these DEGs, nine DEGs were identified as putative DEM targets, where hsa-microRNA (miR)-1225-5p-CCNL2, hsa-miR-339-5p-PRCP, and hsa-miR-193a-3p-mitogen-activated protein kinase 10 (MAPK10) were the only three pairs which were associated with decreased gene expression levels. Furthermore, hsa-miR-193a-3p was demonstrated to induce BN by targeting MAPK10. Collectively, the results of the present study suggest that hsa-miR-193a-3p may be a viable biomarker of BN.