Regulation of the Paneth cell niche by exogenous L-arginine couples the intestinal stem cell function.

Although previous studies show that exogenous nutrients regulate the stem cell function, little is known about the effects of L-arginine on intestinal stem cells (ISCs). In this study, we utilize mice, small intestinal (SI) organoids, and ISC-Paneth cell co-cultured models to clarify the role of L-arginine in ISC function. We find that exogenous L-arginine is essential for ISCs proliferation and intestinal epithelial renewal. Our data show that Paneth cells, a critical component of the ISCs niche, augment the ISCs function in response to L-arginine. Moreover, enhanced the expression of Wnt3a in Paneth cells, which is a ligand of the Wnt/ß-catenin signaling pathway, mediates the effects of L-arginine on ISCs function. Pre-treatment with L-arginine enhances the ISCs pool and protects the gut in response to injury provoked by murine tumor necrosis factor α (TNF-α) and 5-Fluorouracil (5-FU). Our findings establish that the regulation of Wnt3a in the Paneth cell niche by exogenous L-arginine couples ISCs function and favours a model in which the ISCs niche couples the nutrient levels to ISCs function.