Gene expression from tuft cells under scopolamine treatment

In our study, we investigated the effect of muscarinic receptor blockade on murine intestinal stem cell activity and differentiation. Following pharmacologic (scopolamine) and genetic muscarinic receptor interruption (M3R-KO, M1R-KO; Vil-Cre x M3R fl/fl, Vil-Cre x M1R fl/fl mice, respectively), we observe a selective, significant expansion of DCLK1-positive tuft cells. This is primarily sensed by endocrine Prox1-positive cells (Prox1-CreERT2 x M3R fl/fl mice), while Lgr5-positive ISCs respond with a reduction of their cellular activity (Lgr5-EGFP-IRES-CreERT2 x M3R fl/fl mice). To characterize expanding tuft cells in more detail, adult BAC transgenic DCLK1-DTR-ZSgreen reporter mice generated in our lab were treated with scopolamine or sodium chloride as controls (Sham) for 7d and live jejunal EPC-positive/ZSgreen-positive cells sorted. Extracted total RNA from sorted ZSgreen-positive cells of scopolamine- and sham-treated mice was sequenced. Further analysis revealed that expanding tuft cells orchestrate an increase in mucosal acetylcholine, which maintained intracellular signaling pathways such as p-ERK/ERK 1/2 or TCF-1/7. Finally, acute irradiation injury was employed to investigate the importance of this regulatory circuit for tissue homeostasis. Indeed, tissue injury in Vil-Cre x M3R fl/fl mice resulted in a severe reduction of epithelial DCLK1-positive tuft cells, concomitant to reduced mucosal Ach levels as well as intracellular PI3K-/p-ERK levels. Therefore, DCLK1-positive tuft cells appear essential for the maintenance of a regular intestinal cholinergic niche.