Identification of microRNAs and target genes associated with the development of human intervertebral disc degeneration by bioinformatic analysis and verification

Abstract Micro RNAs (miRNAs) are widely recognized to play an essential role via target genes in the development of intervertebral disc degeneration( IDD), but the molecular mechanisms remain unclear. To identify the key microRNAs and potential targets during IDD, the Gene Expression Omnibus datasets (GSE19943, GSE63492, and GSE116726) were downloaded.An R package was used to identify differentially expressed miRNAs (DEMs) and four online tools(TargetScan, miRDB, miRTarBase, and DIANA-TarBase) were performed to predict their target genes. Functional enrichment analysis revealed that DEMs gene targets were highly enriched in cell development, cell differentiation, and the p53 and Wnt signaling pathways. we identified 13 hub genes with node degree≥10 through established a protein-protein interaction (PPI) network. Among them,MAPK8, BMP4, and GSK3B were top 3 highest degree. After constructing the miRNA-target gene-functional analysis network, we found that most hub genes could be regulated by miR-557 and were mainly enriched in cell development, cell differentiation, and Wnt signaling pathway. Further in vitro experiment by qRT-PCR confirmed that miR-577 was significantly downregulated than the control,whereas miR-516-3p was significantly upregulated. Together, the key microRNA and their target genes identified in this study help us understand the underlying pathogenesis mechanisms in the development of IDD, and provide diagnostic biomarkers and new therapeutic strategies for the treatment of IDD.