Identification of Potential Biomarkers for Intervertebral Disc Degeneration Using the Genome-Wide Expression Analysis

Intervertebral disc degeneration (IDD) is the major cause of low back pain. The current study was aimed to further elucidate the mechanisms underlying it. Microarray data sets GSE70362 containing Thompson degeneration grades I-V were divided into the control and the degenerative group and were analyzed. Differentially expressed genes (DEGs) were screened and clustered, followed by functional enrichment analysis. Then the protein-protein interaction (PPI) network and the microRNA (miRNA) regulatory network were constructed and integratedly analyzed. Finally, modules from the integrated network were mined, and gene ontology and pathway enrichment analysis were performed. DEGs in three clusters had the overall expression trend with the Thompson grades. The upregulated DEGs were associated with protein transport and localization, while the downregulated DEGs were enriched in membrane lipid metabolic process and endocytosis. After the integrated analysis of PPI and miRNA-target interactions, some hub genes such as HSP90B1, RPS4Y1, RPL15, and UTY, as well as hub miRNAs, including miR-124a and miR-506, were screened. Finally, modules in the integrated network were functionally associated with protein targeting, peptide processing, and metabolic process, as well as protein folding. Taken together, our data showed that the protein synthesis, targeting, and localization can be greatly changed to contribute to the progress of IDD. Besides, the related genes such as RPS4Y1 and HSP90B1 would be used as diagnostic and therapeutic targets for IDD.