Interleukin-4 suppresses the proliferation and alters the gene expression in enteroids.

Interleukin (IL)-4 is known as a cytokine mainly involved in allergy and inflammation, but recent studies have suggested that IL-4 plays a part in the differentiation process of various cells. Since the effect of IL-4 on intestinal epithelial cells, particularly cryptic cells including stem cells, is poorly understood, we investigated IL-4-induced changes in intestinal epithelial cells using mouse jejunal organoids called enteroids. IL-4 treatment decreased cell proliferation, the expression of the stem cell markers leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) and olfactomedin 4 (Olfm4), and Lgr5-positive cells in enteroids. Among the differentiation markers, IL-4 significantly decreased the gene expression levels of the Paneth cell markers lysozyme 1 (Lyz1) and regenerating islet-derived protein 3 gamma (Reg3γ). A fluorescent immunostaining showed that IL-4 attenuated the emission and fluorescence intensity derived from lysozyme, which is enriched in Paneth cells. These results suggest that functional changes in Paneth cells caused by IL-4 may contribute to the reduction in Lgr5-positive cells and proliferative activity. IL-4 may affects gut function by altering the proliferation and the gene expression in enteroids.