Symbionts and metabolites

Cell https://doi.org/10.1016/j.cell.2018.05.014 (2018)

Intestinal parasites such as helminths or the protozoan Tritrichomonas induce the accumulation of tuft cells and goblet cells in the small intestine of mice through induction of the cytokine IL-13 in group 2 innate lymphoid cells (ILC2s). In Cell, Locksley and colleagues show that tuft cells are very rare in the first 2 weeks of life and accumulate after weaning through a process that is dependent on IL-25 and is negatively regulated by the ubiquitin-editing protein A20, which restricts signaling through the IL-25 receptor in ILC2s. Tuft-cell accumulation depends on colonization with Tritrichomonas, dietary fibers and succinate, which can directly induce IL-25 production in tuft cells, and is independent of bacterial microbiota, acetate, butyrate and propionate. Colonization with Tritrichomonas or treatment with IL-25 increases the resistance of mice to infection to Nippostrongylus brasiliensis or Heligmosomoides polygyrus.