Neurotensin regulates proliferation and stem cell function in the small intestine in a nutrient-dependent manner

Background & Aims: Intestinal stem cells (ISCs) are sensitive to dietary alterations and nutrient availability. Neurotensin (NT), a gut peptide localized predominantly to the small bowel and released by fat ingestion, stimulates the growth of intestinal mucosa under basal conditions and during periods of nutrient deprivation, suggesting a possible role for NT on ISC function. Methods: Lgr5-EGFP, NT wild type (Nt+/+) and Lgr5-EGFP, NT knockout (Nt-/-) mice were fed ad libitum (AL) or fasted for 48 h. Small intestine crypts were examined by RNAseq analysis. Results: Loss of NT impaired crypt cell proliferation and ISC function in a manner dependent on nutrient status. Under nutrient-rich conditions, NT stimulated the expression of genes that promote cell cycle progression, leading to crypt cell proliferation. Under conditions of nutrient depletion, NT stimulated WNT/ß-catenin signaling and promoted an ISC gene signature, leading to enhanced ISC function. NT was required for the induction of WNT/ß-catenin signaling and ISC-specific gene expression during nutrient depletion, and loss of NT reduced crypt cell proliferation and impaired ISC function and Lgr5 expression in the intestine during fasting. Conclusion: Collectively, our findings establish an evolutionarily conserved role for NT in ISC maintenance during nutritional stress. Overall design: Male and female NT+/+ and NT-/- mice were fed ad libitum or fasted for 48h and then intestinal crypts collected for RNA isolation and RNA sequencing. NT+/+ ad libitum fed mice served as controls.