Tuft cell-derived acetylcholine promotes epithelial chloride secretion and intestinal helminth clearance

Epithelial cells secrete chloride to regulate water release at mucosal barriers, supporting both homeostatic hydration and the “weep” response that is critical for Type 2 immune defense against parasitic worms (helminths). Epithelial tuft cells in the small intestine sense helminths and release cytokines and lipids to activate Type 2 immune cells, but whether they regulate epithelial secretion is unknown. Here we found that tuft cell activation rapidly induced epithelial chloride secretion in the small intestine. This response required tuft cell sensory functions and tuft-cell-derived acetylcholine (ACh), which acted directly on neighboring epithelial cells to stimulate chloride secretion, independent of neurons. Maximal tuft cell-induced chloride secretion coincided with immune restriction of helminths, and clearance was delayed in mice lacking tuft cell-derived ACh, despite normal Type 2 inflammation. Thus, we have uncovered an epithelium-intrinsic response unit that uses ACh to couple tuft cell sensing to the secretory defenses of neighboring epithelial cells. Small intestinal tuft cells were sorted from naïve mice expressing an Il25-RFP reporter and a Chat-GFP reporter. Tuft cells were identified as CD45- EPCAM+ and IL25-RFP+ and then sorted into Chat-GFP+ and Chat-GFP- populations for RNA sequencing