Recipient‐derived macrophages mediate acute cardiac allograft rejection via GSDMD‐induced pyroptosis mechanism

Abstract Objective To determine whether macrophage gasdermin D (GSDMD)‐dependent pyroptosis drives acute cardiac allograft rejection and whether targeting GSDMD improves graft survival. Methods GSDMD activation was assessed by immunoblotting. Graft survival wasanalysed in global and macrophage‐specific GSDMD‐deficient recipients. Single‐cell RNA‐seq identified GSDMD‐expressing populations, while immune infiltration and cytokines were measured by flow cytometry and immunohistochemistry; IL1R1 knockout and cytokine challenge were used for validation. Results GSDMD deficiency markedly prolonged graft survival. Single‐cell profiling showed increased GSDMD expression and pyroptosis primarily in recipient‐derived M1 macrophages during acute rejection. Macrophage‐specific GSDMD deficiency reduced CD8 + T cell/macrophage infiltration and decreased TNF‐α and IL‐1β. TNFα/IL6 activated NF‐κB and JAK–STAT3 to upregulate GSDMD, and IL‐1β was verified as a key effector for CD8 + T cells mediated‐rejection. GSDMD pyroptosis inhibitors mitigated rejection and extended graft survival. Conclusion Recipient M1 macrophages promote acute rejection via TNFα/IL6‐driven NF‐κB/STAT3 activation of GSDMD‐mediated pyroptosis. Targeting GSDMD represents a promising strategy to enhance cardiac allograft survival.