Identification of Key Genes and Competitive Endogenous RNA Network Construction in Osteonecrosis of the Femoral Head by Integrated Bioinformatics Analysis

Background: Despite cumulative evidence shows osteonecrosis of the femoral head (ONFH) could result in the progressive collapse of the femoral head. The pathogenesis of ONFH remains unclear. Early ONFH is difficult to diagnose due to the lack of effective biomarkers. Method: In Gene Expression Omnibus (GEO) database, we searched the Microarray datasets for serum (GSE123568) in ONFH and normal controls to identify differentially expressed genes (DEGs) by R software. The enrichment analyses were performed to enrich pathways of DEGs. Protein–protein interaction (PPI), miRNA-mRNA co-expression, ceRNA networks were constructed using Cytoscape to identity top15 hub genes, target miRNAs of hub genes and potential regulatory pathways. Furthermore, hub genes validated in GSE74089 with high diagnostic value for ONFH were selected as key genes. The Human Protein Atlas (HPA) and Bgee Database were used to find out the subcellular and tissue distribution of key genes.Results: A total of 568 DEGs were identified between 30 ONFH samples and 10 normal controls. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis showed that DEGs are mostly enriched in innate immune responses, thrombosis and signal transduction. Fifteen hub genes were identified by PPI network using Cytoscape. The 15 hub genes were almost all positively correlated with each other. The expression of PLEK (P＜0.001), TLR2 (P＜0.05), and TREM1 (P＜0.001) were validated in dataset GSE74089 and they had high diagnostic value (AUC＞0.8) for ONFH. MALAT1-miR-146b-5p-TLR2, MALAT1-miR-664b-3p-PLEK, NORAD-miR-106b-5p-TLR2, and MSMO1-miR-106b-5p-TLR2 might be potential RNA regulatory pathways in the disease progression of ONFH. PLEK mainly expressed in nucleus, TREM1 in dictyosome, and TLR2 in nucleoplasm and mitochondria.Conclusions: In this study, we found that PLEK, TLR2, and TREM1 might be potential biomarkers in diagnostic and play a vital role in the progression of ONFH.