IL-22 signaling attenuates necrotizing enterocolitis by promoting epithelial cell regeneration

Necrotizing enterocolitis (NEC) is a devastating intestinal inflammatory disorder that primarily affects premature infants. Despite decades of research, this disease remains a significant cause of death in the absence of efficient therapeutics. Interleukin (IL)-22 has been shown to play a critical role in maintaining the gut barrier, promoting epithelial regeneration, and controlling intestinal inflammation in adult animal models with an established microbiome. However, the importance of IL-22 signaling in the regulation of gut homeostasis and protection in neonates that lack an established microbiome remains unknown. Therefore, the aim of the current study is to investigate the role of IL-22 in the neonatal intestinal epithelium under homeostatic and inflammatory conditions by using a mouse model of NEC. Our data reveal that Il22 expression in neonatal murine intestine is negligible until weaning. In addition, both human and murine neonates lack IL-22 production during NEC. Mice deficient in IL-22 or mice lacking the expression of IL-22 receptor in intestinal epithelial cells, display a similar susceptibility of neonates to NEC consistent with the lack of endogenous IL-22 at this critical stage of intestinal development. Conversely, treatment with recombinant IL-22 during NEC substantially reduces disease severity. This IL-22-mediated protection is associated with enhanced epithelial regeneration and increased expression of several antimicrobial genes. Strikingly, despite an IL-22-mediated induction of an antimicrobial transcriptional program, the composition of the intestinal microbial communities remains unchanged. Taken together, this study demonstrates that an IL-22 signaling axis promotes protection against neonatal NEC through the induction of epithelial cell regeneration. The aim of the current study was to investigate the role of IL-22 in the neonatal intestinal epithelium under homeostatic and inflammatory conditions by using a mouse model of NEC. All included samples are enteroids from 6 week control (non-NEC) mice.