The neuropeptide neuromedin U directs eosinophils to promote epithelial cell differentiation and barrier immunity of the small intestine

In this work we show that neuromedin U receptor 1 (NMUR1)-mediated signaling programs SI eosinophils to support epithelial cell differentiation and barrier immunity. The global transcriptional profiling of eosinophils from different tissues of mice revealed that Nmur1 was expressed in a subset of eosinophils specifically in the SI. Fate mapping analyses showed that NMUR1 expression in SI eosinophils was imprinted by local microenvironment and further enhanced by the inflammation. Genetic deletion of NMUR1 decreased the numbers of eosinophils, degranulation activity, and goblet cell differentiation in the SI. Chemogenetic manipulation of NMU-expressing cells significantly altered the goblet cell differentiation and mucus secretion. Eosinophil-organoid co-culture experiments demonstrated that NMU-mediated eosinophil activation directly promoted the growth of intestinal organoids and formation of budding domains and complex crypt–villus structures. Finally, the deficiency of NMUR1 compromised anti-parasite immunity. Thus, NMU regulates epithelial cell differentiation and function through stimulating NMUR1-expressing eosinophils in the SI, highlighting the importance of neuro-immune-epithelium crosstalk in maintaining tissue homeostasis. Overall design: We flow-sorted total eosinophils from the small intestine, bone marrow, blood, spleen, lung, skin and colon of wildtype mice, or NMUR1+ and NMUR1- eosinophils from the NMUR1-TdT reporter mice at the steady state. The cells were then subjected to bulk RNA-seq or scRNA-seq as indicated. Libraries were pair-end (150+ 150 bp) sequenced on a Hiseq X Ten or NovaSeq (Illumina).