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: Leucine-rich repeat-containing G-protein coupled receptor 5-Enhanced Green Fluorescent Protein (Lgr5-EGFP) NT wild type (Nt+/+) and Lgr5-EGFP NT knockout (Nt-/-) mice were fed ad libitum or fasted for 48 hours. Small intestine tissue and crypts were examined by gene expression analyses, fluorescence-activated cell sorting, Western blot, immunohistochemistry, and crypt-derived organoid culture. Drosophila expressing NT in midgut enteroendocrine cells were fed a standard diet or low-energy diet and esg-green fluorescent protein+ ISCs were quantified via immunofluorescence.
RESULTS: Loss of NT impaired crypt cell proliferation and ISC function in a manner dependent on nutrient status. Under nutrient-rich conditions, NT stimulated extracellular signal-regulated kinases 1 and 2 signaling and the expression of genes that promote cell-cycle progression, leading to crypt cell proliferation. Under conditions of nutrient depletion, NT stimulated WNT/β-catenin signaling and promoted an ISC gene signature, leading to enhanced ISC function. NT was required for the induction of WNT/β-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. Conversely, the expression of NT in midgut enteroendocrine cells of Drosophila prevented loss of ISCs during nutrient depletion.
CONCLUSIONS: Collectively, our findings establish an evolutionarily conserved role for NT in ISC maintenance during nutritional stress. GSE182828.
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This study was supported by National Institutes of Health grants R01 DK112034 (B.M.E.), R01 CA208343 (B.M.E. and T.G.), R01 CA133429 (T.G.), R35 GM131807 (J.J.), T32 DK007778 (S.A.R.), and the Markey Cancer Foundation (B.M.E.). The research made use of shared resource facilities supported by National Cancer Institute grant P30 CA177558 (B.M.E.): Biospecimen Procurement and Translational Pathology, Biostatistics and Bioinformatics, Flow Cytometry and Immune Monitoring, and Oncogenomics.
Transcriptomic data generated in this study are available in the NCBI Gene Expression Omnibus repository (accession number: GSE182828).
Rock, Stephanie A.; Jiang, Kai; Wu, Yuanyuan; Liu, Yajuan; Li, Jing; Weiss, Heidi L.; Wang, Chi; Jia, Jianhang; Gao, Tianyan; and Evers, B. Mark, "Neurotensin Regulates Proliferation and Stem Cell Function in the Small Intestine in a Nutrient-Dependent Manner" (2021). Surgery Faculty Publications. 49.