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

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.