MicroRNA-802 regulates the innate immune response through Paneth cell expansion and Wnt signaling

Paneth cells are important for maintaining epithelial cell renewal and modulating innate immune function in the intestine through secretion of growth factors and antimicrobial peptides, which help sustain epithelial stem and progenitor cells and contribute to the intestinal barrier and protection against pathogenic bacteria. Here we show that the intestine-enriched miR-802 is a central regulator of intestinal epithelial cell proliferation and Paneth cell function. Genetic ablation of mir-802 in mice leads to amplified ROS generation and Notch/Wnt signaling, increased intestinal epithelial turnover, impaired enterocyte differentiation and nutrient uptake, and increased enterocyte apoptosis. Mice lacking mir-802 in the intestine also exhibit Paneth cell expansion, increased antimicrobial peptide production, and protection against Salmonella infection. This phenotype relies on the miR-802 target gene Tmed9. In total, 6 samples from isolated jejunum enterocyte cells were analyzed. From these, 3 were controls (mir-802fl/fl) and the other 3 were intestine specific KO (Vil-Cre mir-802fl/fl).