An inflammasome-driven differentiation program in intestinal stem cells protects against Salmonella infection.

Intestinal stem cells (ISCs) are essential for sustaining epithelial renewal and barrier integrity, yet their role in orchestrating defense against enteric pathogens remains unclear. Here we identify a stem cell-intrinsic immune mechanism whereby Lgr5+ ISCs detect intracellular Salmonella enterica and activate an inflammasome-dependent differentiation program. Using fluorescent-labeled S. enterica, single-cell transcriptomics, fate mapping, organoid models, and genetic perturbations, we show that invaded ISCs undergo rapid reprogramming toward antimicrobial peptide-enriched Paneth cells via apoptosis-associated Speck-like protein containing a CARD (ASC, encoded by Pycard)-mediated inflammasome signaling. This fate switch enhances epithelial antimicrobial capacity and restricts pathogen persistence in the crypt. The response is Salmonella-specific and conserved in human intestinal organoids. Moreover, the invasion-associated transcriptional signature is enriched in ISCs from patients with Crohn's disease. Our findings reveal that ISCs act as active sensors of bacterial invasion and initiate epithelial remodeling through inflammasome signaling, highlighting stem cell plasticity as a frontline innate immune strategy.