Multi-platform evidence of GSDMD-dependent pyroptosis in malaria with a potential role for TLR7.

BACKGROUND

Macrophage-mediated inflammation critically determines malaria pathology. Although pyroptosis contributes to host defense, excessive activation induces severe immunopathology. The precise pyroptotic pathways in splenic macrophages during Plasmodium infection, and the upstream regulatory mechanisms that govern them, remain unclear.

METHODS

We integrated clinical transcriptomic analysis (GSE132050), Plasmodium yoelii infected mouse models, and in vitro macrophage assays to systematically investigate pyroptosis mechanisms and to evaluate the regulatory role of the Toll-like receptor 7 (TLR7) agonist R848.

RESULTS

Clinical data revealed significant up-regulation of core pyroptosis genes (GSDMD, CASP1/4/5) in malaria patients, correlated with myeloid expansion. In vivo, P. Yoelii infection was associated with activation of both canonical and non-canonical gasdermin D (GSDMD) related pyroptotic signaling in CD11b+F4/80+ splenic macrophages. In vitro, infected red blood cell (iRBC) lysates directly triggered post-translational cleavage of Caspase-1/11 and GSDMD, causing rapid membrane perforation and inflammatory efflux. Notably, in vivo administration of R848 significantly suppressed this pyroptotic activation, exerting a particularly strong inhibitory effect on the Caspase-11/GSDMD non-canonical pathway.

CONCLUSIONS

Plasmodium infection is associated with canonical and non-canonical pyroptosis in splenic macrophages. R848 treatment was associated with reduced pyroptotic signaling in splenic macrophages, suggesting a regulatory role for TLR7.