Desaminotyrosine promotes tuft cell expansion and integrates intestinal type 2 immunity.

Intestinal microbiota are essential for maintaining the host's immune homeostasis, but the mechanism is not fully understood. While microbial metabolite desaminotyrosine (DAT) is recognized for its protective role in viral immunity, its potential involvement in anti-parasitic defense remains unexplored. Here, we demonstrate that DAT orchestrates tuft cell hyperplasia and subsequent type 2 immunity, establishing critical defense against helminth infection. Mechanistically, DAT-mediated intestinal epithelial remodeling requires histone deacetylase 3 (HDAC3), as pharmacological inhibition of this epigenetic regulator abrogates both tuft cell expansion and impairs type 2 immune responses. Collectively, our findings not only explore DAT novel effects in anti-parasitic defense but also reveal a pathway whereby the small molecule metabolites calibrate intestinal type 2 immunity.IMPORTANCEA small molecule metabolite DAT drives tuft cell hyperplasia and type 2 immunity in the small intestine. DAT-mediated tuft cell hyperplasia depends on HDAC3 and an intact microbiota; our findings reveal how small molecule metabolites fine-tune intestinal type 2 defenses against parasites.