ERAdP facilitates biogenesis of dense core vesicles in Paneth cells to enhance intestinal defense

Paneth cells secrete antimicrobial peptides (AMPs) to modulate composition of gut microbiota and host defense. AMPs are typically packaged into dense core vesicles (DCVs) and secreted into the intestinal lumen. However, the mechanisms underlying DCV biogenesis and secretion are still elusive. Here we identified that ERAdP was highly expressed in Paneth cells that acted as a sensor for a bacterial second messenger c-di-AMP. ERAdP deficiency caused impaired DCV biogenesis and dysfunction of Paneth cells. Mechanistically, by sensing c-di-AMP, ERAdP interacted with NLRP6 and further recruited ANXA2 onto the DCV membrane in Paneth cells. The ERAdP–NLRP6–ANXA2 complex facilitated DCV biogenesis, which enhanced antibacterial ability of intestines. Disruption of ERAdP–NLRP6–ANXA2 axis led to loss of DCVs in Paneth cells and increased susceptibility to bacterial infection. Of note, ERAdP–NLRP6–ANXA2 proteins were lowly expressed in IBD patients, and c-di-AMP treatment enhanced antibacterial capacity in antibiotic-treated mice. Our findings reveal that c-di-AMP stimulation might provide a potential therapeutic strategy for infectious disease and gut inflammation.