The intestinal epithelial barrier is instrumental in the physical separation of gut microbiota from underlying innate and adaptive immune cells and stromal cells.1 This “barrier” is anything but static, however, with intestinal stem cells (ISCs) tightly controlling regeneration of the epithelial lining along the crypt–villus axis in a coordinated balance between ISC self-renewal and differentiation into transit-amplifying (TA) cells.2 Although numerous, well-defined growth factor pathways are known to regulate ISC and TA cell expansion dynamics in the steady state, far less is understood about how specific cytokines expressed during tissue injury and inflammation influence this intricate process.
