Machine learning-based analysis reveals potential diagnostic gene biomarkers associated with immune infiltration in patients with osteoarthritis

Objective We aimed to find and validate reliable diagnostic markers in osteoarthritis (OA) and to explore the links with immunophenotypes. Materials and Methods For this study, we screened the Gene Expression Omnibus (GEO) dataset of three OA synovial samples for genes that differed between the disease and normal groups. Subsequently, multiple machine learning algorithms as well as screening core genes as diagnostic markers were employed. The diagnostic efficiency of the training and test sets was verified by ROC curves, and the correlation of core diagnostic genes with the immune microenvironment was compared by the CIBERSORT algorithm. Furthermore, in vitro and in vivo experiments were performed to validate the regulatory roles of selected genes in OA progression. Quantitative PCR and ELISA were used to detect gene expression and inflammatory cytokines in OA-simulated synoviocytes, while animal models were employed to assess joint pathology, synovitis, and cartilage degradation. Results We identified 81 DEGs. the results of LASSO and SVM-RFE identified 13 key diagnostic genes. the ROC analysis confirmed the diagnostic value of these 13 genes for OA. Immunocell infiltration analysis revealed activation of CD4 + T cells as well as T helper cells in synovial tissue, as well as downregulation of MHC class I and enhanced T cell co-repressor signaling, which may correlate with SCN4B expression. DLX2 knockdown and SCN4B overexpression significantly altered inflammatory mediator levels and cartilage catabolic markers in vitro, and ameliorated OA-related histopathological changes in vivo, confirming their functional involvement in disease progression. Conclusion Overall, this study identified 13 diagnostic biomarkers for OA, providing potential molecular targets for optimal treatment of OA. In particular, DLX2 and SCN4B may represent novel regulatory hubs involved in inflammation and cartilage degradation, offering new insights into OA pathogenesis and therapeutic strategies.