RANK-DEPENDENT CONTROL OF TUFT AND BEST4 CELL DEVELOPMENT IN THE INTESTINE

ABSTRACT Specialist intestinal epithelial cells are critical for barrier integrity and immune responses at the mucosal boundary, yet the pathways that govern their development are incompletely defined. Here, we identify an essential role for TNFRSF11A/RANK in shaping intestinal epithelial specialization in zebrafish. Using lineage trajectory analysis, we identified two tuft cell subtypes, including a subtype enriched for expression of genes required to produce pro-inflammatory leukotrienes. We showed that RANK deficiency reduced the abundance of immune-regulatory tuft and BEST4 cells, increased goblet cell frequency, and promoted the accumulation of pro-inflammatory leukocytes in the gut. Functionally, we demonstrated that BEST4 cell numbers expand following infection with a pandemic strain of Vibrio cholerae , and that RANK deficiency enhances fish susceptibility to host colonization by Vibrio , implicating this lineage in host defenses against an enteric pathogen. Together, our findings implicate RANK signaling in intestinal epithelial diversification and immune regulation.