Human intestinal enteroids with inducible neurogenin-3 expression as a novel model of gut hormone secretion

Abstract

BackgroundEnteroendocrine cells (EECs) are specialized epithelial cells that produce molecules vital for intestinal homeostasis, but due to their limited numbers, in-depth functional studies have remained challenging. Human intestinal enteroids (HIEs) that are derived from intestinal crypt stem cells are a biologically relevant in vitro model of the intestinal epithelium. HIEs contain all intestinal epithelial cell types; however, like the intestine, HIEs spontaneously produce few EECs, which limits their study.\n\nMethodsTo increase the number of EECs in HIEs, we used lentivirus transduction to stably engineer jejunal HIEs with doxycycline-inducible expression of neurogenin-3 (NGN3), a transcription factor that drives EEC differentiation (tetNGN3-HIEs). We examined the impact of NGN3 induction on EECs by quantifying the increase in the enterochromaffin cells and other EEC subtypes. We functionally assessed secretion of serotonin and EEC hormones in response to norepinephrine and rotavirus infection.\n\nResultsTreating tetNGN3-HIEs with doxycycline induced a dose-dependent increase of chromogranin A (ChgA)-positive and serotonin-positive cells, demonstrating increased enterochromaffin cell differentiation. Despite increased ChgA-positive cells, other differentiated cell types of the epithelium remained largely unchanged by gene expression and immunostaining. RNA sequencing of doxycycline-induced tetNGN3- HIEs identified increased expression of key hormones and enzymes associated with several other EEC subtypes. Doxycycline-induced tetNGN3-HIEs secreted serotonin, monocyte chemoattractant protein-1, glucose-dependent insulinotropic peptide, peptide YY, and ghrelin in response to norepinephrine and rotavirus infection, further supporting the presence of multiple EEC types.\n\nConclusionsWe have combined HIEs and inducible-NGN3 expression to establish a flexible in vitro model system for functional studies of EECs in enteroids and advance the molecular and physiological investigation of EECs.\n\nSynopsisEnteroendocrine cells have low abundance but exert widespread effects on gastrointestinal physiology. We engineered human intestinal enteroids with inducible expression of neurogenin-3, resulting in increased enteroendocrine cells and facilitating investigations of host responses to the dynamic intestinal environment.