Genes relevant with osteoarthritis by comparison gene expression profiles of synovial membrane of osteoarthritis patients at different stages.

BACKGROUND: This study aimed to identify biological markers about osteoarthritis (OA) which is a polygenic disease by investigating the gene expression profiles of the synovium samples from early-stage and end-stage OA patients for the diagnosis and treatment of OA.

METHODS: The gene expression profile of GSE32317 was downloaded from Gene Expression Omnibus (GEO) database, including 10 samples from early-stage OA patients and 9 samples from end-stage OA patients. The differentially expressed genes (DEGs) were identified by Significance Analysis of Microarrays. The co-expression network of DEGs was constructed by Pearson correlation test. Then, modules in the constructed co-expression network were selected by MCODE Plugin. What's more, EASE (Expression Analysis Systematic Explorer) was used to define the significant functions and pathways in the identified modules.

RESULTS: Total 419 DEGs were identified, among which 112 were up-regulated and 307 down-regulated. We selected 7 statistically significant modules with gene number above 10 and phenotypic correlation test of modules showed that all the modules had significant correlation with OA (p < 0.05). The genes of module 1, module 2 and module 7 were significantly related to immune system functions, protein glycosylation functions, bone, chondrocytes and cartilage functions, respectively. The most significant pathway in module 3 and module 5 was Wnt signal pathway, and in module 4 was Toll-like receptor signal pathway.

CONCLUSIONS: DEGs related to immune response, cartilage development, protein glycosylation, muscle development, and DEGs participated in the Wnt signaling pathway and Toll-like receptor (TLR) signaling pathway might be the potential target genes for the OA treatment.