Tuft cells act as regenerative stem cells in the human intestine
In mice, intestinal tuft cells have been described as a long-lived, post-mitotic cell type of which two distinct subsets have been identified, named tuft-1 and tuft-2.By combining analysis of primary human intestinal resection material with organoid technology, we identify four distinct states of human tuft cells, two of which overlap with their murine counterparts. We show that tuft cell development depends on the presence of Wnt ligands, and that its numbers rapidly increase upon interleukin (IL)-4 and IL-13 exposure, as reported previously in mouse. This, however, is induced through proliferation of pre-existing tuft cells, rather than through increasedde novo generation from stem cells. Indeed, proliferative tuft cells occurin vivoboth in adult and in fetal human intestine. Single mature proliferating Tuft cells can form organoids that contain all intestinal epithelial cell types. Unlike stem- and progenitor cells, human tuft cells survive irradiation damage and retain the ability to generate all other epithelial cell types. Accordingly, organoids engineered to lack tuft cells fail to recover from radiation-induced damage. Thus, tuft cells represent a damage-induced reserve intestinal stem cell pool in humans. Overall design: Human ntestinal organoids were grown in a  medium that promotes diferentiation to Tuft cells with or without the stimulants IL-4 and IL-13. Single cells suspension was processed by 10x platform or with SORT-seq, using KIT or AVIL-CLOVER expression in order to enrich for tuft cells.