IFN-a promotes GSDMD-mediated macrophage pyroptosis to drive renal inflammation and fibrosis
Macrophage response to tubular epithelial cell (TEC) injury drives renal inflammation and fibrosis. Gasdermin D (GSDMD)-mediated pyroptosis amplifies inflammatory and fibrogenic cascade, yet its role in chronic kidney disease (CKD) remains elusive. In our study, we demonstrated that GSDMD was mainly upregulated in kidney macrophages following unilateral renal ischemia-reperfusion injury (UIRI) or folic acid-induced injury, paralleling by elevated pyroptosis rates. Clinically, the active fragment GSDMD-N positively correlated with fibrosis severity across diverse CKD etiologies, reinforcing its pathogenic relevance. Macrophage-specific deletion of Gsdmd significantly ameliorated pyroptosis, inflammation, and renal fibrosis in both murine models, without affecting acute tubular damage in bilateral IRI. To delineate the molecular mechanism underlying injured TECs-driven macrophage pyroptosis, we established a co-culture model of TECs and macrophages. The mouse kidney proximal tubular epithelial cells (TKPTS) were subjected to hypoxia and lipopolysaccharide (LPS) treatment for 24 hours, followed by 12-hour recovery in a fresh medium. Conditioned medium (CM) from injured TECs (HRL CM) and control TECs (CTL CM) were separately collected to treat BMDMs for 6 hours, with subsequent nigericin addition to induce potassium efflux. Then, we performed RNA sequencing (RNA-seq) on BMDMs treated with HRL CM or CTL CM, with both groups co-stimulated by nigericin or without.