Targeting CCNE2 to Alleviate Rheumatoid Arthritis through Inducing Senescence and Apoptosis.

Purpose: This study investigated the role of cellular senescence in the progression of rheumatoid arthritis (RA) and demonstrated the potential of targeting Cyclin E2 (CCNE2) in synoviocytes fibroblast to alleviate RA, aiming to establish a robust risk prediction mode for RA and provide theoretical support for clinically targeted therapy.

Methods: We analysed the differential gene expression of RA patients and healthy individuals and performed a Gene set enrichment analysis (GSEA). The genes related to cell senescence were downloaded to obtain the intersect genes with the differential genes. LASSO regression analysis was employed to establish a risk prediction model, and the ROC curve was utilized to prove the accuracy of the model. CCNE2 expression was examined by Western blot. In rheumatoid arthritis synovial fibroblasts (RASFs), CCNE2 was knocked down using shRNA to assess its cellular function. Cell viability and apoptosis were evaluated using CCK8 assay and flow cytometry, respectively. SA-β-Gal staining and immunofluorescence for H3K9me2/3 were performed to detect cellular senescence. The expression of senescence-related markers (p16, p21, p53) and SASP factors (e.g. IL-8, MMP-3) was assessed by Western blot and ELISA. For in vivo validation, a collagen-induced arthritis (CIA) mouse model was established, and AAV-mediated intra-articular injection of shCCNE2 was performed. Arthritis index scoring and histological examination (H&E staining) were conducted to evaluate joint inflammation, and CCNE2 expression in synovial tissues was assessed.

Results: Risk score = (-0.295 × ANAPC2) + (0.009 × ASF1A) + (1.260 × CCNE2)-(0.186 × CEBPB) + (0.172 × E2F2) + (0.519 × FOS)-(1.036 × FZR1)-(0.296 × MAPK7)-(0.439 × RING1)-(0.37 × TNRC6C) (AUC > 0.6). There was extensive infiltration of inflammatory cells in the synovial tissue of the RA group, accompanied by synovial hyperplasia and the expression level of CCNE2 was significantly increased (P < 0.01). The results of immune infiltration showed, naive B cells, CD8 T cells and M1 macrophages exhibited a strong positive association with the risk score. After knocking out CCNE2 in RASFs, cell viability significantly decreased, while the rate of apoptosis significantly increased (P < 0.01). The activity of SA-β-Gal and H3K9me3 enhanced, and the protein expression levels of p16, p21, and p53 were also significantly increased (P < 0.01). In vivo targeted knockout of CCNE2 significantly ameliorated both arthritis index and inflammatory joint infiltration in RA mice.

Conclusion: A risk prediction model for RA was developed. Targeting CCNE2 emerges as a novel RA therapeutic strategy: its suppression induces RASF senescence, consequently mitigating disease progression and joint inflammation.