Relish/NF-kB acts in intestinal stem cells to promote epithelial repair in Drosophila

Immune signals coordinate the repair of damaged epithelia by intestinal stem cells. However, it is unclear if immune pathways act autonomously within the stem cell to direct the damage response pathway. We consider this an important question, as stem cell dynamics are essential for formation and maintenance of the entire epithelium. We used Drosophila to determine the impact of stem cell-specific loss of NF-{kappa}B on tissue regeneration upon chemical injury. We found that loss of NF-{kappa}B enhanced cell death, impaired enterocyte renewal and increased mortality. Mechanistically, we showed that the Ras/ERK pathway is essential for NF-{kappa}B-dependent maintenance of cell viability and tissue repair. Combined, our data demonstrate that stem cell-intrinsic NF-{kappa}B activity is essential for an orderly repair of damaged intestinal epithelia.