Commensal-derived acetylcholine enhances mucosal immune education [PRESTO_Salsa_screen_InVio_Bu_corrected]

Notably, we identified multiple commensal strains that produced acetylcholine (ACh) in vivo via the conversion of dietary choline, including select Bifidobacteria strains that dominate the microbiome in early life and a probiotic Pediococcus strain. Mechanistically, we identified and characterized the bacterial enzymes mediating this biotransformation in Bifidobacterium breve and Pediococcus pentosaceus, and generated an isogenic mutant B. breve strain lacking ACh production.

Mice colonized with an ACh-producing B. breve strain and treated with an FDA-approved acetylcholinesterase inhibitor exhibited enhanced intestinal immunoglobulin A (IgA) production, altered microbiota composition, and increased resistance to enteric infection. Together, these findings suggest that commensal-derived ACh can enhance intestinal IgA production, strengthen mucosal immune defenses, and reinforce host-microbiota mutualism.