Mechanistic insights into the detection of free fatty and bile acids by ileal glucagon-like peptide-1 secreting cells.
Billing, Lawrence J
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Goldspink, D., Lu, V., Billing, L. J., Larraufie, P., Tolhurst, G., Gribble, F., & Reimann, F. (2018). Mechanistic insights into the detection of free fatty and bile acids by ileal glucagon-like peptide-1 secreting cells.. Molecular metabolism, 7 90-101. https://doi.org/10.1016/j.molmet.2017.11.005
Objectives: The aim of this study was to investigate the electrical properties of ileal Glucagon-like peptide 1 (GLP-1) secreting L-cells using murine organoid cultures, and the electrophysiological and intracellular signalling pathways recruited following activation of the Gq-coupled free fatty acid receptors FFA1 and Gs-coupled bile acid receptors GPBAR1. Methods: Experiments were performed using ileal organoids generated from mice transgenically expressing fluorescent reporters (Epac2-camps and GCaMP3) under control of the proglucagon promoter. Electrophysiology and single cell imaging were performed on identified L-cells in organoids, and GLP-1 secretion from cultured organoids was measured by immunoassay. Results: The FFA1 ligand TAK-875 triggered L-cell electrical activity, increased intracellular calcium, and activated a depolarising current that was blocked by the TRPC3 inhibitor Pyr3. TAK-875 triggered GLP-1 secretion was Pyr3 sensitive, suggesting that the TRPC3 channel links FFA1 activation to calcium elevation and GLP-1 release in L-cells. GPBAR1 agonist triggered PKA-dependent L-type Ca2+ current activation and action potential firing in L-cells. The combination of TAK-875 and a GPBAR1 agonist triggered synergistic calcium elevation and GLP-1 secretory responses. Conclusions: FFA1 and GPBAR1 activation individually increased electrical activity in L-cells by recruiting pathways that include activation of TRPC3 and L-type voltage-gated Ca2+ channels. Synergy between the pathways activated downstream of these receptors was observed both at the level of Ca2+ elevation and GLP-1 secretion.
Ileum, Cells, Cultured, Animals, Mice, Calcium, Bile Acids and Salts, Fatty Acids, Receptors, G-Protein-Coupled, Membrane Potentials, Enteroendocrine Cells, TRPC Cation Channels, Glucagon-Like Peptide 1
Wellcome Trust (100574/Z/12/Z)
WELLCOME TRUST (106262/Z/14/Z & 106263/Z/14/Z)
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External DOI: https://doi.org/10.1016/j.molmet.2017.11.005
This record's URL: https://www.repository.cam.ac.uk/handle/1810/271417
Attribution 4.0 International
Licence URL: http://creativecommons.org/licenses/by/4.0/
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