Association of NLRC4 inflammasome targeting Caspase1 to regulate monocyte pyroptosis involved in ankylosing spondylitis pathogenesis.

BACKGROUND

While the NLRC4 inflammasome has been associated with multiple autoimmune pathologies, its role in ankylosing spondylitis (AS) remains undefined. This study aimed to investigate the mechanistic involvement of NLRC4-regulated pyroptosis in the pathogenesis of AS.

METHODS

This study collected peripheral blood samples and epidemiological data from 50 AS patients and 50 matched controls, with quantification of NLRC4/CASP1/GSDMD-N mRNA expression levels in peripheral blood mononuclear cells (PBMCs) and inflammatory cytokine levels in plasma.Bioinformatics analysis was performed using the AS dataset GSE73754 from GEO. THP-1 cells were transduced with NLRC4-overexpressing lentivirus, followed by qRT-PCR and Western blot analysis of CASP1/GSDMD-N.

RESULTS

Research revealed significant upregulation of NLRC4, CASP1, and GSDMD-N mRNA in AS patient PBMCs, and ROC analysis demonstrated their diagnostic potential. Correlation analyses revealed positive associations between NLRC4/CASP1 and both Erythrocyte sedimentation rate (ESR) and Ankylosing Spondylitis Disease Activity Score (ASDAS), with subgroup analyses showing significantly higher mRNA levels in ASDAS ≥ 2.1 versus ASDAS < 2.1. Bioinformatics analysis confirmed NLRC4 upregulation in AS patients and its positive correlation with pyroptosis activity in both REACTOME and GOBP pathways. Cellular experiments demonstrated significantly increased NLRC4/CASP1/GSDMD-N expression at both mRNA and protein levels post-transduction.

CONCLUSION

Our findings suggest that NLRC4 may promote the pathogenesis of AS by targeting CASP1 to regulate GSDMD-N-mediated pyroptosis, highlighting this signaling axis as a promising therapeutic target for preventing AS progression. Keypoints • This study provides the first evidence establishing the association between pyroptosis and ankylosing spondylitis (AS) pathogenesis. • The significantly elevated expression of NLRC4/CASP1/GSDMD-N in AS patients not only shows promising diagnostic potential but also exhibits clinically relevant correlations with disease progression parameters. • Bioinformatics analyses systematically confirm the involvement of NLRC4-mediated pyroptosis in AS pathogenesis at the pathway level. • Cellular experiments demonstrate that NLRC4 likely contributes to AS development by regulating CASP1-mediated GSDMD-N expression and subsequent pyroptotic activity, thereby identifying NLRC4 as a promising therapeutic target for AS intervention.