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.