GSDMD-mediated metabolic crosstalk licenses a pro-regenerative niche for tissue repair

The establishment of an early pro-regenerative niche is crucial for tissue regeneration. Gasdermin D (GSDMD)-dependent pyroptosis accounts for the release of inflammatory cytokines upon various insults. However, little is known about its role in tissue regeneration followed by homeostatic maintenance. Here, we show that macrophage GSDMD deficiency delayed tissue recovery, with little impact on the local inflammatory milieu or the lytic pyroptosis process. Metabolite secretome profiling of hyperactivated macrophages unveiled the non-canonical metabolite-secreting function of GSDMD. And we further identified 11,12-epoxyeicosatrienoic acid (11,12-EET) as a bioactive pro-healing oxylipin, secreted from hyperactive macrophages in a GSDMD-dependent manner. Indeed, accumulation of 11,12-EET by direct supplementation or deletion of its hydrolytic enzyme Ephx2 accelerated muscle regeneration. We further demonstrated that the Ephx2 level accumulated within aged muscle, which led to a decreased intramuscular 11,12-EET level. And consecutive 11,12-EET treatment rejuvenated aged muscle. Mechanistically, 11,12-EET amplifies fibroblast growth factor/FGF receptor (FGF-FGFR) signaling by modulating FGF liquid-liquid phase separation, hence boosting the activation and proliferation of muscle stem cells (MuSCs). These data depict a GSDMD-guided metabolite crosstalk between macrophages and MuSCs that governs the repair process, which offers new therapeutic insights for the regeneration of injured or aged tissues.