Identification of key chondrocyte apoptosis-related genes in osteoarthritis based on weighted gene co-expression network analysis and experimental verification

Objective: Osteoarthritis (OA) is the primary cause of disability worldwide. Chondrocyte apoptosis has important implications for OA onset and progression. This work was designed to explore the mechanisms of chondrocyte apoptosis in OA and identify key chondrocyte apoptosis-related genes (CARGs). Methods: GSE32317 and GSE55235 datasets were acquired from the Gene Expression Omnibus (GEO) database. OA-associated module genes were determined via weighted gene co-expression network analysis (WGCNA) in GSE32317. CARGs were acquired from public databases. ClusterProfiler was employed for GO and KEGG analyses. Protein-protein interaction (PPI) network establishment was realized via STRING database and Cytoscape, and the hub genes were screened by MCC, MNC, and DMNC algorithms of cytoHubba. The diagnostic values of the hub CARGs in OA in GSE55235 was verified via receiver operating characteristic (ROC) curve analysis. C28/I2 cells were stimulated with IL-1β to establish the in vitro OA model. Results: WGCNA identified 9,141 OA-related genes and 248 CARGs, resulting in 75 CARGs in OA. GO and KEGG analyses demonstrated that the 75 CARGs were primarily enriched in response to lipopolysaccharide, transcription regulator complex, DNA-binding transcription factor binding, along with NF-kappa B and TNF signaling pathways. NFKB1 and ICAM1 were identified as the hub CARGs in OA through the three algorithms, which showed favorable prognostic values for OA. Notably, both bioinformatics analysis and in vitro assays revealed upregulated NFKB1 and ICAM1 expression in OA. Conclusions: NFKB1 and ICAM1 were the hub CARGs in OA, which might serve as the diagnostic signatures and therapeutic