SFEBES2021 Oral Communications Metabolism, Obesity and Diabetes (6 abstracts)
Stimulation of motilin secretion by bile, free fatty acids and acidification in human duodenal organoids
Emily L Miedzybrodzka , Rachel E Foreman , Van B Lu , Amy L George , Christopher A Smith , Pierre Larraufie , Richard G Kay , Deborah A Goldspink , Frank Reimann & Fiona M Gribble
Wellcome Trust – MRC Institute of Metabolic Science Metabolic Research Laboratories, Cambridge, United Kingdom
Objective: Motilin is a proximal small intestinal hormone with roles in gastrointestinal motility, gallbladder emptying and hunger initiation. The molecular mechanisms underlying motilin release in response to fats, bile and duodenal acidification are poorly understood, in part due a lack of suitable cellular and rodent models. We therefore generated a novel human intestinal organoid model with fluorescently labelled motilin-expressing M-cells, which we used to establish the key signalling pathways involved in the regulation of motilin secretion.
Methods: CRISPR-Cas9 homology donor repair was used to insert the fluorescent protein Venus or the Ca2+ sensor GCaMP7s under control of the endogenous motilin promoter in human duodenal organoids. This enabled identification and purification of M-cells for bulk RNA sequencing, peptidomics, calcium imaging and electrophysiology. We also developed a liquid chromatography tandem mass spectrometry (LC-MS/MS) assay to measure secretion of motilin and other gut hormones from 2D organoid-derived cultures.
Results: Human duodenal M-cells express a range of nutrient-sensing and neurohormonal receptors. Agonists of the bile acid receptor GPBAR1, long chain fatty acid receptor FFA1 and monoacylglycerol receptor GPR119 stimulate motilin secretion by 3.4-, 2.4- and 1.5-fold, respectively. Acidification at pH 5.0 was a potent stimulus of acute M-cell calcium elevation and electrical activity, an effect attributable to acid-sensing ion channels, and a modest inducer (1.6-fold) of motilin release.
Conclusions: This study presents the first in-depth transcriptomic and functional characterisation of human duodenal motilin-expressing cells. We identify several receptors important for the postprandial and interdigestive regulation of motilin release.
Volume 77
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Endocrine Abstracts
ISSN 1470-3947 (print) | ISSN 1479-6848 (online)
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