AIM2 as an Immunogenic Cell Death (ICD)-related hub gene in rheumatoid arthritis: identification and functional validation.

INTRODUCTION/

OBJECTIVES

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by joint inflammation and immune dysregulation. Immunogenic cell death (ICD), which activates adaptive immunity, plays key roles in both cancerous and non-cancerous conditions. This study investigated the molecular association between ICD-related genes and RA, identified hub genes linked to pathogenesis, and explored their diagnostic and therapeutic potential.

METHOD: Differentially expressed genes (DEGs) in RA were identified using the limma R package. Weighted gene co-expression network analysis (WGCNA) was applied to detect RA-associated gene modules. ICD-related genes were systematically curated from published literature. Hub genes were screened via least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE) algorithms, while their diagnostic value was evaluated by logistic regression. Spearman's rank correlation analyzed associations with immune cell infiltration and pathways. Immunohistochemistry (IHC) validated hub gene expression in synovial tissues from RA patients and healthy controls. Functional experiments, including AIM2 knockdown in RA synovial fibroblasts (SFs), assessed its effects on apoptosis and inflammation.

RESULTS

AIM2 and ENTPD1 were identified as ICD-related hub genes in RA. Logistic regression confirmed their high diagnostic accuracy (AUC > 0.95) and revealed significant correlations with immune cell infiltration (e.g., CD4 + T cells) and immune pathways (e.g., NF-κB signaling). IHC validation demonstrated significantly elevated expression of AIM2 and ENTPD1 in RA synovial tissues versus controls (P < 0.001). Functional experiments showed that AIM2 inhibition promoted apoptosis in RA-SFs and downregulated pro-inflammatory biomarkers (MMP-3, MMP-13, ADAMTS-5) and anti-apoptotic protein Bcl-2.

CONCLUSIONS

AIM2 and ENTPD1 were validated as ICD-related hub genes in RA. AIM2 inhibition induced apoptosis in RA SFs and reduced inflammatory factors, suggesting its therapeutic potential. Key Points • AIM2 as a Novel Hub Gene in RA Pathogenesis. • AIM2 has demonstrated high diagnostic accuracy (AUC > 0.95) in  distinguishing RA patients from controls, highlighting its potential as a  biomarker. • Inhibition of AIM2 in synovial fibroblasts (SFs) reduced inflammatory markers, promoted apoptosis, and suppressed cell proliferation, suggesting its role in RA progression. • Targeting AIM2 may offer a novel strategy to modulate synovial inflammation and joint destruction in RA.