Paneth cell SIRT1 deficiency increases intestinal stress resistance by modulating the gut microbiota

Paneth cells, intestine-originated innate immune-like cells, are important for maintenance of the intestinal stem cell niche, gut microbiota, and gastrointestinal barrier. Dysfunctional Paneth cells under pathological conditions are a site of origin for intestinal inflammation. However, mechanisms underlying stress-induced Paneth cell dysregulation remain unclear. Here, we report that SIRT1, the most conserved mammalian NAD⁺-dependent protein deacetylase and a well-known genetic repressor of inflammation, cell-autonomously suppresses Paneth cell function and sensitizes the gut epithelium to environmental stress. Specifically, deletion of Paneth cell SIRT1 in mice elevates Wnt signaling and ATF4/endoplasmic reticulum stress pathway in Paneth cells. These molecular alterations are coupled with increased Paneth cell abundance and enhanced anti-microbial peptide production in young mice, improved protection against intestinal immune cell expansion in aged mice, and increased resistance to chemically induced colitis. Using microbiota-depleted mice with or without fecal transplantation, we further demonstrate that Paneth cell SIRT1 deficiency ameliorates colitis by interacting with the gut microbiota. Collectively, our findings uncover an unanticipated function of Paneth cell SIRT1 in conferring stress sensitivity in the gut epithelium.