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Ott S, Xu S, Lee N, Hong I, Anns J, Suresh DD, Zhang Z, Zhang X, Harion R, Ye W, Chandramouli V, Jesuthasan S, Saheki Y, Claridge-Chang A. Kalium channelrhodopsins effectively inhibit neurons. Nat Commun 2024; 15:3480. [PMID: 38658537 PMCID: PMC11043423 DOI: 10.1038/s41467-024-47203-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 03/18/2024] [Indexed: 04/26/2024] Open
Abstract
The analysis of neural circuits has been revolutionized by optogenetic methods. Light-gated chloride-conducting anion channelrhodopsins (ACRs)-recently emerged as powerful neuron inhibitors. For cells or sub-neuronal compartments with high intracellular chloride concentrations, however, a chloride conductance can have instead an activating effect. The recently discovered light-gated, potassium-conducting, kalium channelrhodopsins (KCRs) might serve as an alternative in these situations, with potentially broad application. As yet, KCRs have not been shown to confer potent inhibitory effects in small genetically tractable animals. Here, we evaluated the utility of KCRs to suppress behavior and inhibit neural activity in Drosophila, Caenorhabditis elegans, and zebrafish. In direct comparisons with ACR1, a KCR1 variant with enhanced plasma-membrane trafficking displayed comparable potency, but with improved properties that include reduced toxicity and superior efficacy in putative high-chloride cells. This comparative analysis of behavioral inhibition between chloride- and potassium-selective silencing tools establishes KCRs as next-generation optogenetic inhibitors for in vivo circuit analysis in behaving animals.
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Affiliation(s)
- Stanislav Ott
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Sangyu Xu
- Institute for Molecular and Cell Biology, A*STAR Agency for Science, Technology and Research, Singapore, Singapore
| | - Nicole Lee
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Ivan Hong
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Jonathan Anns
- Institute for Molecular and Cell Biology, A*STAR Agency for Science, Technology and Research, Singapore, Singapore
- School of Biological Sciences and Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Danesha Devini Suresh
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Zhiyi Zhang
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Xianyuan Zhang
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Raihanah Harion
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Weiying Ye
- Department of Pharmacy, National University of Singapore, Singapore, Singapore
| | - Vaishnavi Chandramouli
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Suresh Jesuthasan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Yasunori Saheki
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Adam Claridge-Chang
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore.
- Institute for Molecular and Cell Biology, A*STAR Agency for Science, Technology and Research, Singapore, Singapore.
- Department of Pharmacy, National University of Singapore, Singapore, Singapore.
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2
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Barton JR, Londregan AK, Alexander TD, Entezari AA, Covarrubias M, Waldman SA. Enteroendocrine cell regulation of the gut-brain axis. Front Neurosci 2023; 17:1272955. [PMID: 38027512 PMCID: PMC10662325 DOI: 10.3389/fnins.2023.1272955] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Enteroendocrine cells (EECs) are an essential interface between the gut and brain that communicate signals about nutrients, pain, and even information from our microbiome. EECs are hormone-producing cells expressed throughout the gastrointestinal epithelium and have been leveraged by pharmaceuticals like semaglutide (Ozempic, Wegovy), terzepatide (Mounjaro), and retatrutide (Phase 2) for diabetes and weight control, and linaclotide (Linzess) to treat irritable bowel syndrome (IBS) and visceral pain. This review focuses on role of intestinal EECs to communicate signals from the gut lumen to the brain. Canonically, EECs communicate information about the intestinal environment through a variety of hormones, dividing EECs into separate classes based on the hormone each cell type secretes. Recent studies have revealed more diverse hormone profiles and communication modalities for EECs including direct synaptic communication with peripheral neurons. EECs known as neuropod cells rapidly relay signals from gut to brain via a direct communication with vagal and primary sensory neurons. Further, this review discusses the complex information processing machinery within EECs, including receptors that transduce intraluminal signals and the ion channel complement that govern initiation and propagation of these signals. Deeper understanding of EEC physiology is necessary to safely treat devastating and pervasive conditions like irritable bowel syndrome and obesity.
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Affiliation(s)
- Joshua R. Barton
- Department of Pharmacology, Physiology, and Cancer Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Annie K. Londregan
- Department of Pharmacology, Physiology, and Cancer Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Tyler D. Alexander
- Department of Neurosciences, Thomas Jefferson University, Philadelphia, PA, United States
| | - Ariana A. Entezari
- Department of Pharmacology, Physiology, and Cancer Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Manuel Covarrubias
- Department of Neurosciences, Thomas Jefferson University, Philadelphia, PA, United States
| | - Scott A. Waldman
- Department of Pharmacology, Physiology, and Cancer Biology, Thomas Jefferson University, Philadelphia, PA, United States
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States
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3
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Hurley MJ, Menozzi E, Koletsi S, Bates R, Gegg ME, Chau KY, Blottière HM, Macnaughtan J, Schapira AHV. α-Synuclein expression in response to bacterial ligands and metabolites in gut enteroendocrine cells: an in vitro proof of concept study. Brain Commun 2023; 5:fcad285. [PMID: 37953845 PMCID: PMC10636561 DOI: 10.1093/braincomms/fcad285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 09/03/2023] [Accepted: 10/23/2023] [Indexed: 11/14/2023] Open
Abstract
Caudo-rostral migration of pathological forms of α-synuclein from the gut to the brain is proposed as an early feature in Parkinson's disease pathogenesis, but the underlying mechanisms remain unknown. Intestinal epithelial enteroendocrine cells sense and respond to numerous luminal signals, including bacterial factors, and transmit this information to the brain via the enteric nervous system and vagus nerve. There is evidence that gut bacteria composition and their metabolites change in Parkinson's disease patients, and these alterations can trigger α-synuclein pathology in animal models of the disorder. Here, we investigated the effect of toll-like receptor and free fatty acid receptor agonists on the intracellular level of α-synuclein and its release using mouse secretin tumour cell line 1 enteroendocrine cells. Secretin tumour cell line 1 enteroendocrine cells were treated for 24 or 48 h with toll-like receptor agonists (toll-like receptor 4 selective lipopolysaccharide; toll-like receptor 2 selective Pam3CysSerLys4) and the free fatty acid receptor 2/3 agonists butyrate, propionate and acetate. The effect of selective receptor antagonists on the agonists' effects after 24 hours was also investigated. The level of α-synuclein protein was measured in cell lysates and cell culture media by western blot and enzyme-linked immunosorbent assay. The level of α-synuclein and tumour necrosis factor messenger RNA was measured by quantitative reverse transcription real-time polymerase chain reaction. Stimulation of secretin tumour cell line 1 enteroendocrine cells for 24 and 48 hours with toll-like receptor and free fatty acid receptor agonists significantly increased the amount of intracellular α-synuclein and the release of α-synuclein from the cells into the culture medium. Both effects were significantly reduced by antagonists selective for each receptor. Toll-like receptor and free fatty acid receptor agonists also significantly increased tumour necrosis factor transcription, and this was effectively inhibited by corresponding antagonists. Elevated intracellular α-synuclein increases the likelihood of aggregation and conversion to toxic forms. Factors derived from bacteria induce α-synuclein accumulation in secretin tumour cell line 1 enteroendocrine cells. Here, we provide support for a mechanism by which exposure of enteroendocrine cells to specific bacterial factors found in Parkinson's disease gut dysbiosis might facilitate accumulation of α-synuclein pathology in the gut.
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Affiliation(s)
- Michael J Hurley
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London NW3 2PF, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Elisa Menozzi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London NW3 2PF, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Sofia Koletsi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London NW3 2PF, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Rachel Bates
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London NW3 2PF, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Matthew E Gegg
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London NW3 2PF, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Kai-Yin Chau
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London NW3 2PF, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Hervé M Blottière
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Université Paris-Saclay, INRAE, MetaGenoPolis, Jouy en Josas, & Nantes Université, INRAE, UMR 1280 PhAN, Nantes 44093, France
| | - Jane Macnaughtan
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London NW3 2PF, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Institute for Liver and Digestive Health, University College London, London NW3 2PF, UK
| | - Anthony H V Schapira
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London NW3 2PF, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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4
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Titos I, Juginović A, Vaccaro A, Nambara K, Gorelik P, Mazor O, Rogulja D. A gut-secreted peptide suppresses arousability from sleep. Cell 2023; 186:1382-1397.e21. [PMID: 36958331 PMCID: PMC10216829 DOI: 10.1016/j.cell.2023.02.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 08/26/2022] [Accepted: 02/16/2023] [Indexed: 03/25/2023]
Abstract
Suppressing sensory arousal is critical for sleep, with deeper sleep requiring stronger sensory suppression. The mechanisms that enable sleeping animals to largely ignore their surroundings are not well understood. We show that the responsiveness of sleeping flies and mice to mechanical vibrations is better suppressed when the diet is protein rich. In flies, we describe a signaling pathway through which information about ingested proteins is conveyed from the gut to the brain to help suppress arousability. Higher protein concentration in the gut leads to increased activity of enteroendocrine cells that release the peptide CCHa1. CCHa1 signals to a small group of dopamine neurons in the brain to modulate their activity; the dopaminergic activity regulates the behavioral responsiveness of animals to vibrations. The CCHa1 pathway and dietary proteins do not influence responsiveness to all sensory inputs, showing that during sleep, different information streams can be gated through independent mechanisms.
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Affiliation(s)
- Iris Titos
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Alen Juginović
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Alexandra Vaccaro
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Keishi Nambara
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Pavel Gorelik
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ofer Mazor
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Dragana Rogulja
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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5
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Knutson KR, Whiteman ST, Alcaino C, Mercado-Perez A, Finholm I, Serlin HK, Bellampalli SS, Linden DR, Farrugia G, Beyder A. Intestinal enteroendocrine cells rely on ryanodine and IP 3 calcium store receptors for mechanotransduction. J Physiol 2023; 601:287-305. [PMID: 36428286 PMCID: PMC9840706 DOI: 10.1113/jp283383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/24/2022] [Indexed: 11/27/2022] Open
Abstract
Enteroendocrine cells (EECs) are specialized sensors of luminal forces and chemicals in the gastrointestinal (GI) epithelium that respond to stimulation with a release of signalling molecules such as serotonin (5-HT). For mechanosensitive EECs, force activates Piezo2 channels, which generate a very rapidly activating and inactivating (∼10 ms) cationic (Na+ , K+ , Ca2+ ) receptor current. Piezo2 receptor currents lead to a large and persistent increase in intracellular calcium (Ca2+ ) that lasts many seconds to sometimes minutes, suggesting signal amplification. However, intracellular calcium dynamics in EEC mechanotransduction remain poorly understood. The aim of this study was to determine the role of Ca2+ stores in EEC mechanotransduction. Mechanical stimulation of a human EEC cell model (QGP-1) resulted in a rapid increase in cytoplasmic Ca2+ and a slower decrease in ER stores Ca2+ , suggesting the involvement of intracellular Ca2+ stores. Comparing murine primary colonic EECs with colonocytes showed expression of intercellular Ca2+ store receptors, a similar expression of IP3 receptors, but a >30-fold enriched expression of Ryr3 in EECs. In mechanically stimulated primary EECs, Ca2+ responses decreased dramatically by emptying stores and pharmacologically blocking IP3 and RyR1/3 receptors. RyR3 genetic knockdown by siRNA led to a significant decrease in mechanosensitive Ca2+ responses and 5-HT release. In tissue, pressure-induced increase in the Ussing short circuit current was significantly decreased by ryanodine receptor blockade. Our data show that mechanosensitive EECs use intracellular Ca2+ stores to amplify mechanically induced Ca2+ entry, with RyR3 receptors selectively expressed in EECs and involved in Ca2+ signalling, 5-HT release and epithelial secretion. KEY POINTS: A population of enteroendocrine cells (EECs) are specialized mechanosensors of the gastrointestinal (GI) epithelium that respond to mechanical stimulation with the release of important signalling molecules such as serotonin. Mechanical activation of these EECs leads to an increase in intracellular calcium (Ca2+ ) with a longer duration than the stimulus, suggesting intracellular Ca2+ signal amplification. In this study, we profiled the expression of intracellular Ca2+ store receptors and found an enriched expression of the intracellular Ca2+ receptor Ryr3, which contributed to the mechanically evoked increases in intracellular calcium, 5-HT release and epithelial secretion. Our data suggest that mechanosensitive EECs rely on intracellular Ca2+ stores and are selective in their use of Ryr3 for amplification of intracellular Ca2+ . This work advances our understanding of EEC mechanotransduction and may provide novel diagnostic and therapeutic targets for GI motility disorders.
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Affiliation(s)
- Kaitlyn R. Knutson
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Sara T. Whiteman
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Constanza Alcaino
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Arnaldo Mercado-Perez
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
- Medical Scientist Training Program (MSTP), Mayo Clinic, Rochester, Minnesota
| | - Isabelle Finholm
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Hannah K. Serlin
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Shreya S. Bellampalli
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
- Medical Scientist Training Program (MSTP), Mayo Clinic, Rochester, Minnesota
| | - David R. Linden
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Gianrico Farrugia
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Division of Gastroenterology &Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Arthur Beyder
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Division of Gastroenterology &Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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6
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Brubaker PL. The Molecular Determinants of Glucagon-like Peptide Secretion by the Intestinal L cell. Endocrinology 2022; 163:6717959. [PMID: 36156130 DOI: 10.1210/endocr/bqac159] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Indexed: 11/19/2022]
Abstract
The intestinal L cell secretes a diversity of biologically active hormones, most notably the glucagon-like peptides, GLP-1 and GLP-2. The highly successful introduction of GLP-1-based drugs into the clinic for the treatment of patients with type 2 diabetes and obesity, and of a GLP-2 analog for patients with short bowel syndrome, has led to the suggestion that stimulation of the endogenous secretion of these peptides may serve as a novel therapeutic approach in these conditions. Situated in the intestinal epithelium, the L cell demonstrates complex relationships with not only circulating, paracrine, and neural regulators, but also ingested nutrients and other factors in the lumen, most notably the microbiota. The integrated input from these numerous secretagogues results in a variety of temporal patterns in L cell secretion, ranging from minutes to 24 hours. This review combines the findings of traditional, physiological studies with those using newer molecular approaches to describe what is known and what remains to be elucidated after 5 decades of research on the intestinal L cell and its secreted peptides, GLP-1 and GLP-2.
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Affiliation(s)
- Patricia L Brubaker
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
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7
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Abstract
When it comes to food, one tempting substance is sugar. Although sweetness is detected by the tongue, the desire to consume sugar arises from the gut. Even when sweet taste is impaired, animals can distinguish sugars from non-nutritive sweeteners guided by sensory cues arising from the gut epithelium. Here, we review the molecular receptors, cells, circuits and behavioural consequences associated with sugar sensing in the gut. Recent work demonstrates that some duodenal cells, termed neuropod cells, can detect glucose using sodium-glucose co-transporter 1 and release glutamate onto vagal afferent neurons. Based on these and other data, we propose a model in which specific populations of vagal neurons relay these sensory cues to distinct sets of neurons in the brain, including neurons in the caudal nucleus of the solitary tract, dopaminergic reward circuits in the basal ganglia and homeostatic feeding circuits in the hypothalamus, that alter current and future sugar consumption. This emerging model highlights the critical role of the gut in sensing the chemical properties of ingested nutrients to guide appetitive decisions.
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Affiliation(s)
- Winston W Liu
- Laboratory of Gut Brain Neurobiology, Duke University, Durham, NC, USA
- Department of Medicine, Duke University, Durham, NC, USA
- Department of Neurobiology, Duke University, Durham, NC, USA
| | - Diego V Bohórquez
- Laboratory of Gut Brain Neurobiology, Duke University, Durham, NC, USA.
- Department of Medicine, Duke University, Durham, NC, USA.
- Department of Neurobiology, Duke University, Durham, NC, USA.
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8
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Anghel SA, Badea RA, Chiritoiu G, Patriche DS, Alexandru PR, Pena F. Novel luciferase-based GLP-1 reporter assay reveals naturally-occurring secretagogues. Br J Pharmacol 2022; 179:4738-4753. [PMID: 35736785 DOI: 10.1111/bph.15896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 04/22/2022] [Accepted: 05/15/2022] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND AND PURPOSE Glucagon-like peptide 1 (GLP-1) is a hormone derived from preproglucagon. It is secreted by enteroendocrine cells in response to feeding, and, in turn, acts as a critical regulator of insulin release. Modulating GLP-1 secretion thus holds promise as a strategy for controlling blood glucose levels. EXPERIMENTAL APPROACH To dissect GLP-1 regulation and to discover specific secretagogues, we engineered a reporter cell line introducing a luciferase within proglucagon sequence in GLUTag cells. The assay was validated using western blotting and ELISA. A focused natural compounds library was screened. We measured luminescence, glucose uptake and ATP to investigate the mechanism by which newly found secretagogues potentiate GLP-1 secretion. KEY RESULTS The newly created reporter cell line is ideal for the rapid, sensitive and quantitative assessment of GLP-1 secretion. The small molecule screen identified non-toxic GLP-1 modulators. Quercetin is the most potent newly found GLP-1 secretagogue, while other flavonoids also potentiate GLP-1 secretion. Quercetin requires glucose and extracellular calcium to act as GLP-1 secretagogue. Our results support a mechanism whereby flavonoids cause GLUTag cells to utilize glucose more efficiently, leading to elevated ATP levels, followed by KATP channel blockade and GLP-1 exocytosis. CONCLUSION AND IMPLICATIONS Our methodology enables finding of new GLP-1 secretagogues. Quercetin is a potent, naturally occuring GLP-1 secretagogue. Mechanistic studies of newly found secretagogues are possible in newly created reporter cell line. Further validation in more physiological systems, such as primary L-cells or whole organisms is needed. GLP-1 secretagogues might serve as leads for developing alternative glucose-lowering therapies.
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Affiliation(s)
- Sorina Andreea Anghel
- Department of Molecular Cell Biology, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Rodica Aura Badea
- Department of Enzymology, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Gabriela Chiritoiu
- Department of Molecular Cell Biology, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - David Sebastian Patriche
- Department of Viral Glycoproteins, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Petruta Ramona Alexandru
- Department of Molecular Cell Biology, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Florentina Pena
- Department of Molecular Cell Biology, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
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9
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Guccio N, Gribble FM, Reimann F. Glucose-Dependent Insulinotropic Polypeptide-A Postprandial Hormone with Unharnessed Metabolic Potential. Annu Rev Nutr 2022; 42:21-44. [PMID: 35609956 DOI: 10.1146/annurev-nutr-062320-113625] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is released from the upper small intestine in response to food intake and contributes to the postprandial control of nutrient disposition, including of sugars and fats. Long neglected as a potential therapeutic target, the GIPR axis has received increasing interest recently, with the emerging data demonstrating the metabolically favorable outcomes of adding GIPR agonism to GLP-1 receptor agonists in people with type 2 diabetes and obesity. This review examines the physiology of the GIP axis, from the mechanisms underlying GIP secretion from the intestine to its action on target tissues and therapeutic development. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Nunzio Guccio
- MRC Metabolic Diseases Unit, Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; ,
| | - Fiona M Gribble
- MRC Metabolic Diseases Unit, Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; ,
| | - Frank Reimann
- MRC Metabolic Diseases Unit, Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; ,
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10
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Treichel AJ, Finholm I, Knutson KR, Alcaino C, Whiteman ST, Brown MR, Matveyenko A, Wegner A, Kacmaz H, Mercado-Perez A, Bedekovicsne Gajdos G, Ordog T, Grover M, Szurzewski J, Linden DR, Farrugia G, Beyder A. Specialized Mechanosensory Epithelial Cells in Mouse Gut Intrinsic Tactile Sensitivity. Gastroenterology 2022; 162:535-547.e13. [PMID: 34688712 PMCID: PMC8792331 DOI: 10.1053/j.gastro.2021.10.026] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/30/2021] [Accepted: 10/12/2021] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND AIMS The gastrointestinal (GI) tract extracts nutrients from ingested meals while protecting the organism from infectious agents frequently present in meals. Consequently, most animals conduct the entire digestive process within the GI tract while keeping the luminal contents entirely outside the body, separated by the tightly sealed GI epithelium. Therefore, like the skin and oral cavity, the GI tract must sense the chemical and physical properties of the its external interface to optimize its function. Specialized sensory enteroendocrine cells (EECs) in GI epithelium interact intimately with luminal contents. A subpopulation of EECs express the mechanically gated ion channel Piezo2 and are developmentally and functionally like the skin's touch sensor- the Merkel cell. We hypothesized that Piezo2+ EECs endow the gut with intrinsic tactile sensitivity. METHODS We generated transgenic mouse models with optogenetic activators in EECs and Piezo2 conditional knockouts. We used a range of reference standard and novel techniques from single cells to living animals, including single-cell RNA sequencing and opto-electrophysiology, opto-organ baths with luminal shear forces, and in vivo studies that assayed GI transit while manipulating the physical properties of luminal contents. RESULTS Piezo2+ EECs have transcriptomic features of synaptically connected, mechanosensory epithelial cells. EEC activation by optogenetics and forces led to Piezo2-dependent alterations in colonic propagating contractions driven by intrinsic circuitry, with Piezo2+ EECs detecting the small luminal forces and physical properties of the luminal contents to regulate transit times in the small and large bowel. CONCLUSIONS The GI tract has intrinsic tactile sensitivity that depends on Piezo2+ EECs and allows it to detect luminal forces and physical properties of luminal contents to modulate physiology.
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Affiliation(s)
- Anthony J. Treichel
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Isabelle Finholm
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Kaitlyn R. Knutson
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Constanza Alcaino
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Sara T. Whiteman
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Matthew R. Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Aleksey Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Andrew Wegner
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Halil Kacmaz
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Arnaldo Mercado-Perez
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Medical Scientist Training Program, Mayo Clinic, Rochester, Minnesota
| | - Gabriella Bedekovicsne Gajdos
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Tamas Ordog
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Madhusudan Grover
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Joseph Szurzewski
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - David R. Linden
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Gianrico Farrugia
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Arthur Beyder
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota; Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota.
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11
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Intestinal Gpr17 deficiency improves glucose metabolism by promoting GLP-1 secretion. Cell Rep 2022; 38:110179. [PMID: 34986353 PMCID: PMC8972502 DOI: 10.1016/j.celrep.2021.110179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 10/01/2021] [Accepted: 12/06/2021] [Indexed: 12/20/2022] Open
Abstract
G protein-coupled receptors (GPCRs) in intestinal enteroendocrine cells (EECs) respond to nutritional, neural, and microbial cues and modulate the release of gut hormones. Here we show that Gpr17, an orphan GPCR, is co-expressed in glucagon-like peptide-1 (GLP-1)-expressing EECs in human and rodent intestinal epithelium. Acute genetic ablation of Gpr17 in intestinal epithelium improves glucose tolerance and glucose-stimulated insulin secretion (GSIS). Importantly, inducible knockout (iKO) mice and Gpr17 null intestinal organoids respond to glucose or lipid ingestion with increased secretion of GLP-1, but not the other incretin glucose-dependent insulinotropic polypeptide (GIP). In an in vitro EEC model, overexpression or agonism of Gpr17 reduces voltage-gated calcium currents and decreases cyclic AMP (cAMP) production, and these are two critical factors regulating GLP-1 secretion. Together, our work shows that intestinal Gpr17 signaling functions as an inhibitory pathway for GLP-1 secretion in EECs, suggesting intestinal GPR17 is a potential target for diabetes and obesity intervention. Yan et al. locate GPR17 expression in the enteroendocrine cells of human and rodent intestinal epithelium. They find that GPR17 signaling inhibits intracellular rise of cAMP and calcium and that loss of intestinal Gpr17 in rodents leads to better glucose tolerance via increased hormone secretion in response to nutrient ingestion.
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12
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Menozzi E, Macnaughtan J, Schapira AHV. The gut-brain axis and Parkinson disease: clinical and pathogenetic relevance. Ann Med 2021; 53:611-625. [PMID: 33860738 PMCID: PMC8078923 DOI: 10.1080/07853890.2021.1890330] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/10/2021] [Indexed: 12/16/2022] Open
Abstract
Gastrointestinal disorders are one of the most significant non-motor problems affecting people with Parkinson disease (PD). Pathogenetically, the gastrointestinal tract has been proposed to be the initial site of pathological changes in PD. Intestinal inflammation and alterations in the gut microbiota may contribute to initiation and progression of pathology in PD. However, the mechanisms underlying this "gut-brain" axis in PD remain unclear. PD patients can display a large variety of gastrointestinal symptoms, leading to reduced quality of life and psychological distress. Gastrointestinal disorders can also limit patients' response to medications, and consequently negatively impact on neurological outcomes. Despite an increasing research focus, gastrointestinal disorders in PD remain poorly understood and their clinical management often suboptimal. This review summarises our understanding of the relevance of the "gut-brain" axis to the pathogenesis of PD, discusses the impact of gastrointestinal disorders in patients with PD, and provides clinicians with practical guidance to their management.
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Affiliation(s)
- Elisa Menozzi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Jane Macnaughtan
- Institute for Liver and Digestive Health, University College London, Royal Free Campus, London, UK
| | - Anthony H. V. Schapira
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
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13
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Yang M, Reimann F, Gribble FM. Chemosensing in enteroendocrine cells: mechanisms and therapeutic opportunities. Curr Opin Endocrinol Diabetes Obes 2021; 28:222-231. [PMID: 33449572 DOI: 10.1097/med.0000000000000614] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE OF REVIEW Enteroendocrine cells (EECs) are scattered chemosensory cells in the intestinal epithelium that release hormones with a wide range of actions on intestinal function, food intake and glucose homeostasis. The mechanisms by which gut hormones are secreted postprandially, or altered by antidiabetic agents and surgical interventions are of considerable interest for future therapeutic development. RECENT FINDINGS EECs are electrically excitable and express a repertoire of G-protein coupled receptors that sense nutrient and nonnutrient stimuli, coupled to intracellular Ca2+ and cyclic adenosine monophosphate. Our knowledge of EEC function, previously developed using mouse models, has recently been extended to human cells. Gut hormone release in humans is enhanced by bariatric surgery, as well as by some antidiabetic agents including sodium-coupled glucose transporter inhibitors and metformin. SUMMARY EECs are important potential therapeutic targets. A better understanding of their chemosensory mechanisms will enhance the development of new therapeutic strategies to treat metabolic and gastrointestinal diseases.
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Affiliation(s)
- Ming Yang
- University of Cambridge, Institute of Metabolic Science and MRC Metabolic Diseases Unit, Addenbrooke's Hospital, Cambridge, UK
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14
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Input-output signal processing plasticity of vagal motor neurons in response to cardiac ischemic injury. iScience 2021; 24:102143. [PMID: 33665562 PMCID: PMC7898179 DOI: 10.1016/j.isci.2021.102143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/01/2021] [Accepted: 01/29/2021] [Indexed: 11/23/2022] Open
Abstract
Vagal stimulation is emerging as the next frontier in bioelectronic medicine to modulate peripheral organ health and treat disease. The neuronal molecular phenotypes in the dorsal motor nucleus of the vagus (DMV) remain largely unexplored, limiting the potential for harnessing the DMV plasticity for therapeutic interventions. We developed a mesoscale single-cell transcriptomics data from hundreds of DMV neurons under homeostasis and following physiological perturbations. Our results revealed that homeostatic DMV neuronal states can be organized into distinguishable input-output signal processing units. Remote ischemic preconditioning induced a distinctive shift in the neuronal states toward diminishing the role of inhibitory inputs, with concomitant changes in regulatory microRNAs miR-218a and miR-495. Chronic cardiac ischemic injury resulted in a dramatic shift in DMV neuronal states suggestive of enhanced neurosecretory function. We propose a DMV molecular network mechanism that integrates combinatorial neurotransmitter inputs from multiple brain regions and humoral signals to modulate cardiac health.
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15
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Koepsell H. Glucose transporters in the small intestine in health and disease. Pflugers Arch 2020; 472:1207-1248. [PMID: 32829466 PMCID: PMC7462918 DOI: 10.1007/s00424-020-02439-5] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 07/11/2020] [Accepted: 07/17/2020] [Indexed: 12/23/2022]
Abstract
Absorption of monosaccharides is mainly mediated by Na+-D-glucose cotransporter SGLT1 and the facititative transporters GLUT2 and GLUT5. SGLT1 and GLUT2 are relevant for absorption of D-glucose and D-galactose while GLUT5 is relevant for D-fructose absorption. SGLT1 and GLUT5 are constantly localized in the brush border membrane (BBM) of enterocytes, whereas GLUT2 is localized in the basolateral membrane (BLM) or the BBM plus BLM at low and high luminal D-glucose concentrations, respectively. At high luminal D-glucose, the abundance SGLT1 in the BBM is increased. Hence, D-glucose absorption at low luminal glucose is mediated via SGLT1 in the BBM and GLUT2 in the BLM whereas high-capacity D-glucose absorption at high luminal glucose is mediated by SGLT1 plus GLUT2 in the BBM and GLUT2 in the BLM. The review describes functions and regulations of SGLT1, GLUT2, and GLUT5 in the small intestine including diurnal variations and carbohydrate-dependent regulations. Also, the roles of SGLT1 and GLUT2 for secretion of enterohormones are discussed. Furthermore, diseases are described that are caused by malfunctions of small intestinal monosaccharide transporters, such as glucose-galactose malabsorption, Fanconi syndrome, and fructose intolerance. Moreover, it is reported how diabetes, small intestinal inflammation, parental nutrition, bariatric surgery, and metformin treatment affect expression of monosaccharide transporters in the small intestine. Finally, food components that decrease D-glucose absorption and drugs in development that inhibit or downregulate SGLT1 in the small intestine are compiled. Models for regulations and combined functions of glucose transporters, and for interplay between D-fructose transport and metabolism, are discussed.
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Affiliation(s)
- Hermann Koepsell
- Institute for Anatomy and Cell Biology, University of Würzburg, Koellikerstr 6, 97070, Würzburg, Germany.
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16
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Goldspink DA, Lu VB, Miedzybrodzka EL, Smith CA, Foreman RE, Billing LJ, Kay RG, Reimann F, Gribble FM. Labeling and Characterization of Human GLP-1-Secreting L-cells in Primary Ileal Organoid Culture. Cell Rep 2020; 31:107833. [PMID: 32610134 PMCID: PMC7342002 DOI: 10.1016/j.celrep.2020.107833] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/10/2020] [Accepted: 06/08/2020] [Indexed: 12/12/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) from intestinal L-cells stimulates insulin secretion and reduces appetite after food ingestion, and it is the basis for drugs against type-2 diabetes and obesity. Drugs targeting L- and other enteroendocrine cells are under development, with the aim to mimic endocrine effects of gastric bypass surgery, but they are difficult to develop without human L-cell models. Human ileal organoids, engineered by CRISPR-Cas9, express the fluorescent protein Venus in the proglucagon locus, enabling maintenance of live, identifiable human L-cells in culture. Fluorescence-activated cell sorting (FACS)-purified organoid-derived L-cells, analyzed by RNA sequencing (RNA-seq), express hormones, receptors, and ion channels, largely typical of their murine counterparts. L-cells are electrically active and exhibit membrane depolarization and calcium elevations in response to G-protein-coupled receptor ligands. Organoids secrete hormones in response to glucose and other stimuli. The ability to label and maintain human L-cells in organoid culture opens avenues to explore L-cell function and develop drugs targeting the human enteroendocrine system.
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Affiliation(s)
- Deborah A Goldspink
- Wellcome Trust - MRC Institute of Metabolic Science Metabolic Research Laboratories, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Van B Lu
- Wellcome Trust - MRC Institute of Metabolic Science Metabolic Research Laboratories, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Emily L Miedzybrodzka
- Wellcome Trust - MRC Institute of Metabolic Science Metabolic Research Laboratories, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Christopher A Smith
- Wellcome Trust - MRC Institute of Metabolic Science Metabolic Research Laboratories, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Rachel E Foreman
- Wellcome Trust - MRC Institute of Metabolic Science Metabolic Research Laboratories, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Lawrence J Billing
- Wellcome Trust - MRC Institute of Metabolic Science Metabolic Research Laboratories, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Richard G Kay
- Wellcome Trust - MRC Institute of Metabolic Science Metabolic Research Laboratories, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Frank Reimann
- Wellcome Trust - MRC Institute of Metabolic Science Metabolic Research Laboratories, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
| | - Fiona M Gribble
- Wellcome Trust - MRC Institute of Metabolic Science Metabolic Research Laboratories, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
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17
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Roberts GP, Larraufie P, Richards P, Kay RG, Galvin SG, Miedzybrodzka EL, Leiter A, Li HJ, Glass LL, Ma MKL, Lam B, Yeo GSH, Scharfmann R, Chiarugi D, Hardwick RH, Reimann F, Gribble FM. Comparison of Human and Murine Enteroendocrine Cells by Transcriptomic and Peptidomic Profiling. Diabetes 2019; 68:1062-1072. [PMID: 30733330 PMCID: PMC6477899 DOI: 10.2337/db18-0883] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/23/2018] [Indexed: 02/02/2023]
Abstract
Enteroendocrine cells (EECs) produce hormones such as glucagon-like peptide 1 and peptide YY that regulate food absorption, insulin secretion, and appetite. Based on the success of glucagon-like peptide 1-based therapies for type 2 diabetes and obesity, EECs are themselves the focus of drug discovery programs to enhance gut hormone secretion. The aim of this study was to identify the transcriptome and peptidome of human EECs and to provide a cross-species comparison between humans and mice. By RNA sequencing of human EECs purified by flow cytometry after cell fixation and staining, we present a first transcriptomic analysis of human EEC populations and demonstrate a strong correlation with murine counterparts. RNA sequencing was deep enough to enable identification of low-abundance transcripts such as G-protein-coupled receptors and ion channels, revealing expression in human EECs of G-protein-coupled receptors previously found to play roles in postprandial nutrient detection. With liquid chromatography-tandem mass spectrometry, we profiled the gradients of peptide hormones along the human and mouse gut, including their sequences and posttranslational modifications. The transcriptomic and peptidomic profiles of human and mouse EECs and cross-species comparison will be valuable tools for drug discovery programs and for understanding human metabolism and the endocrine impacts of bariatric surgery.
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Affiliation(s)
- Geoffrey P Roberts
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
- Cambridge Oesophago-Gastric Centre, Addenbrooke's Hospital, Cambridge, U.K
| | - Pierre Larraufie
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Paul Richards
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
- INSERM U1016, Institut Cochin, Université Paris-Descartes, Paris, France
| | - Richard G Kay
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Sam G Galvin
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Emily L Miedzybrodzka
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Andrew Leiter
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - H Joyce Li
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Leslie L Glass
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Marcella K L Ma
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Brian Lam
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Giles S H Yeo
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Raphaël Scharfmann
- INSERM U1016, Institut Cochin, Université Paris-Descartes, Paris, France
| | - Davide Chiarugi
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Richard H Hardwick
- Cambridge Oesophago-Gastric Centre, Addenbrooke's Hospital, Cambridge, U.K
| | - Frank Reimann
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K.
| | - Fiona M Gribble
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K.
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18
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Abstract
Gut hormones have many key roles in the control of metabolism, as they target diverse tissues involved in the control of intestinal function, insulin secretion, nutrient assimilation and food intake. Produced by scattered cells found along the length of the intestinal epithelium, gut hormones generate signals related to the rate of nutrient absorption, the composition of the luminal milieu and the integrity of the epithelial barrier. Gut hormones already form the basis for existing and developing therapeutics for type 2 diabetes mellitus and obesity, exemplified by the licensed glucagon-like peptide 1 (GLP1) mimetics and dipeptidyl peptidase inhibitors that enhance GLP1 receptor activation. Modulating the release of the endogenous stores of GLP1 and other gut hormones is thought to be a promising strategy to mimic bariatric surgery with its multifaceted beneficial effects on food intake, body weight and blood glucose levels. This Review focuses on the molecular mechanisms underlying the modulation of gut hormone release by food ingestion, obesity and the gut microbiota. Depending on the nature of the stimulus, release of gut hormones involves recruitment of a variety of signalling pathways, including G protein-coupled receptors, nutrient transporters and ion channels, which are targets for future therapeutics for diabetes mellitus and obesity.
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Affiliation(s)
- Fiona M Gribble
- Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | - Frank Reimann
- Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
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19
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Abstract
The organs require oxygen and other types of nutrients (amino acids, sugars, and lipids) to function, the heart consuming large amounts of fatty acids for oxidation and adenosine triphosphate (ATP) generation.
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20
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Goldspink DA, Reimann F, Gribble FM. Models and Tools for Studying Enteroendocrine Cells. Endocrinology 2018; 159:3874-3884. [PMID: 30239642 PMCID: PMC6215081 DOI: 10.1210/en.2018-00672] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 09/05/2018] [Indexed: 12/14/2022]
Abstract
Gut hormones produced by gastrointestinal enteroendocrine cells modulate key physiological processes including glucose homeostasis and food intake, making them potential therapeutic candidates to treat obesity and diabetes. Understanding the function of enteroendocrine cells and the molecular mechanisms driving hormone production is a key step toward mobilizing endogenous hormone reserves in the gut as a therapeutic strategy. In this review, we will discuss the variety of ex vivo and in vitro model systems driving this research and their contributions to our current understanding of nutrient-sensing mechanisms in enteroendocrine cells.
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Affiliation(s)
- Deborah A Goldspink
- Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom
| | - Frank Reimann
- Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom
| | - Fiona M Gribble
- Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom
- Correspondence: Fiona M. Gribble, DPhil, BM, BCh, Institute of Metabolic Science, University of Cambridge, Addenbrooke’s Hospital, Cambridge CB2 0QQ, United Kingdom. E-mail:
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21
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Kaelberer MM, Buchanan KL, Klein ME, Barth BB, Montoya MM, Shen X, Bohórquez DV. A gut-brain neural circuit for nutrient sensory transduction. Science 2018; 361:361/6408/eaat5236. [PMID: 30237325 DOI: 10.1126/science.aat5236] [Citation(s) in RCA: 456] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/02/2018] [Indexed: 12/20/2022]
Abstract
The brain is thought to sense gut stimuli only via the passive release of hormones. This is because no connection has been described between the vagus and the putative gut epithelial sensor cell-the enteroendocrine cell. However, these electrically excitable cells contain several features of epithelial transducers. Using a mouse model, we found that enteroendocrine cells synapse with vagal neurons to transduce gut luminal signals in milliseconds by using glutamate as a neurotransmitter. These synaptically connected enteroendocrine cells are referred to henceforth as neuropod cells. The neuroepithelial circuit they form connects the intestinal lumen to the brainstem in one synapse, opening a physical conduit for the brain to sense gut stimuli with the temporal precision and topographical resolution of a synapse.
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Affiliation(s)
| | | | | | - Bradley B Barth
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Marcia M Montoya
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Xiling Shen
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Diego V Bohórquez
- Department of Medicine, Duke University, Durham, NC, USA. .,Department of Neurobiology, Duke University, Durham, NC, USA.,Duke Institute for Brain Sciences, Duke University, Durham, NC, USA
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22
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Knutson K, Strege PR, Li J, Leiter AB, Farrugia G, Beyder A. Whole Cell Electrophysiology of Primary Cultured Murine Enterochromaffin Cells. J Vis Exp 2018. [PMID: 30320764 DOI: 10.3791/58112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Enterochromaffin (EC) cells in the gastrointestinal (GI) epithelium constitute the largest subpopulation of enteroendocrine cells. As specialized sensory cells, EC cells sense luminal stimuli and convert them into serotonin (5-hyroxytryptamine, 5-HT) release events. However, the electrophysiology of these cells is poorly understood because they are difficult to culture and to identify. The method presented in this paper outlines primary EC cell cultures optimized for single cell electrophysiology. This protocol utilizes a transgenic cyan fluorescent protein (CFP) reporter to identify mouse EC cells in mixed primary cultures, advancing the approach to obtaining high-quality recordings of whole cell electrophysiology in voltage- and current-clamp modes.
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Affiliation(s)
- Katilyn Knutson
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology,Department of Physiology & Biomedical Engineering, Mayo Clinic
| | - Peter R Strege
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology,Department of Physiology & Biomedical Engineering, Mayo Clinic
| | - Joyce Li
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School
| | - Andrew B Leiter
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School
| | - Gianrico Farrugia
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology,Department of Physiology & Biomedical Engineering, Mayo Clinic
| | - Arthur Beyder
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology,Department of Physiology & Biomedical Engineering, Mayo Clinic;
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23
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Buchanan KL, Bohórquez DV. You Are What You (First) Eat. Front Hum Neurosci 2018; 12:323. [PMID: 30150928 PMCID: PMC6099179 DOI: 10.3389/fnhum.2018.00323] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 07/25/2018] [Indexed: 01/15/2023] Open
Abstract
As far back as we can remember, we eat. In fact, we eat before we can remember. Our first meal is amniotic fluid. We swallow it during the first trimester of gestation, and with that, we expose our gut to a universe of molecules. These early molecules have a profound influence on gut and brain function. For example, the taste of the amniotic fluid changes based on the mother's diet. Indeed, recent findings suggest that food preferences begin in utero. Likewise, a baby's first exposure to bacteria, previously thought to be during birth, appears to be in utero as well. And just as postnatal food and microbiota are implicated in brain function and dysfunction, prenatal nutrients and microbes may have a long-lasting impact on the development of the gut-brain neural circuits processing food, especially considering their plasticity during this vulnerable period. Here, we use current literature to put forward concepts needed to understand how the gut first meets the brain, and how this encounter may help us remember food.
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Affiliation(s)
| | - Diego V. Bohórquez
- Department of Medicine, Duke University, Durham, NC, United States
- Department of Neurobiology, Duke University, Durham, NC, United States
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24
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Alcaino C, Knutson KR, Treichel AJ, Yildiz G, Strege PR, Linden DR, Li JH, Leiter AB, Szurszewski JH, Farrugia G, Beyder A. A population of gut epithelial enterochromaffin cells is mechanosensitive and requires Piezo2 to convert force into serotonin release. Proc Natl Acad Sci U S A 2018; 115:E7632-E7641. [PMID: 30037999 PMCID: PMC6094143 DOI: 10.1073/pnas.1804938115] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Enterochromaffin (EC) cells constitute the largest population of intestinal epithelial enteroendocrine (EE) cells. EC cells are proposed to be specialized mechanosensory cells that release serotonin in response to epithelial forces, and thereby regulate intestinal fluid secretion. However, it is unknown whether EE and EC cells are directly mechanosensitive, and if so, what the molecular mechanism of their mechanosensitivity is. Consequently, the role of EE and EC cells in gastrointestinal mechanobiology is unclear. Piezo2 mechanosensitive ion channels are important for some specialized epithelial mechanosensors, and they are expressed in mouse and human EC cells. Here, we use EC and EE cell lineage tracing in multiple mouse models to show that Piezo2 is expressed in a subset of murine EE and EC cells, and it is distributed near serotonin vesicles by superresolution microscopy. Mechanical stimulation of a subset of isolated EE cells leads to a rapid inward ionic current, which is diminished by Piezo2 knockdown and channel inhibitors. In these mechanosensitive EE cells force leads to Piezo2-dependent intracellular Ca2+ increase in isolated cells as well as in EE cells within intestinal organoids, and Piezo2-dependent mechanosensitive serotonin release in EC cells. Conditional knockout of intestinal epithelial Piezo2 results in a significant decrease in mechanically stimulated epithelial secretion. This study shows that a subset of primary EE and EC cells is mechanosensitive, uncovers Piezo2 as their primary mechanotransducer, defines the molecular mechanism of their mechanotransduction and mechanosensitive serotonin release, and establishes the role of epithelial Piezo2 mechanosensitive ion channels in regulation of intestinal physiology.
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Affiliation(s)
- Constanza Alcaino
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Kaitlyn R Knutson
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Anthony J Treichel
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Gulcan Yildiz
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Peter R Strege
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - David R Linden
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
| | - Joyce H Li
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - Andrew B Leiter
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - Joseph H Szurszewski
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
| | - Gianrico Farrugia
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
| | - Arthur Beyder
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905;
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
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Anand U, Yiangou Y, Akbar A, Quick T, MacQuillan A, Fox M, Sinisi M, Korchev YE, Jones B, Bloom SR, Anand P. Glucagon-like peptide 1 receptor (GLP-1R) expression by nerve fibres in inflammatory bowel disease and functional effects in cultured neurons. PLoS One 2018; 13:e0198024. [PMID: 29813107 PMCID: PMC5973579 DOI: 10.1371/journal.pone.0198024] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 05/11/2018] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Glucagon like-peptide 1 receptor (GLP-1R) agonists diminish appetite and may contribute to the weight loss in inflammatory bowel disease (IBD). OBJECTIVES The aim of this study was to determine, for the first time, the expression of GLP-1R by colon nerve fibres in patients with IBD, and functional effects of its agonists in cultured rat and human sensory neurons. METHODS GLP-1R and other nerve markers were studied by immunohistochemistry in colon biopsies from patients with IBD (n = 16) and controls (n = 8), human dorsal root ganglia (DRG) tissue, and in GLP-1R transfected HEK293 cells. The morphological effects of incretin hormones oxyntomodulin, exendin-4 and glucagon were studied on neurite extension in cultured DRG neurons, and their functional effects on capsaicin and ATP signalling, using calcium imaging. RESULTS Significantly increased numbers of colonic mucosal nerve fibres were observed in IBD biopsies expressing GLP-1R (p = 0.0013), the pan-neuronal marker PGP9.5 (p = 0.0008), and sensory neuropeptide CGRP (p = 0.0014). An increase of GLP-1R positive nerve fibres in IBD colon was confirmed with a different antibody to GLP-1R (p = 0.016). GLP-1R immunostaining was intensely positive in small and medium-sized neurons in human DRG, and in human and rat DRG cultured neurons. Co-localization of GLP-1R expression with neuronal markers in colon and DRG confirmed the neural expression of GLP-1R, and antibody specificity was confirmed in HEK293 cells transfected with the GLP-1R. Treatment with oxyntomodulin, exendin-4 and GLP-1 increased neurite length in cultured neurons compared with controls, but did not stimulate calcium influx directly, or affect capsaicin responses. However, exendin-4 significantly enhanced ATP responses in human DRG neurons. CONCLUSION Our results show that increased GLP-1R innervation in IBD bowel could mediate enhanced visceral afferent signalling, and provide a peripheral target for therapeutic intervention. The differential effect of GLP-1R agonists on capsaicin and ATP responses in neurons suggest they may not affect pain mechanisms mediated by the capsaicin receptor TRPV1, but may enhance the effects of purinergic agonists.
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Affiliation(s)
- Uma Anand
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
- Nanomedicine Research Laboratory, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Yiangos Yiangou
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Ayesha Akbar
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Tom Quick
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
- Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, United Kingdom
| | - Anthony MacQuillan
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
- Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, United Kingdom
| | - Mike Fox
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
- Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, United Kingdom
| | - Marco Sinisi
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
- Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, United Kingdom
| | - Yuri E. Korchev
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Ben Jones
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Hospital, London
| | - Steve R. Bloom
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Hospital, London
| | - Praveen Anand
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
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Regulation of BDNF Release by ARMS/Kidins220 through Modulation of Synaptotagmin-IV Levels. J Neurosci 2018; 38:5415-5428. [PMID: 29769266 DOI: 10.1523/jneurosci.1653-17.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 04/07/2018] [Accepted: 05/03/2018] [Indexed: 11/21/2022] Open
Abstract
BDNF is a growth factor with important roles in the nervous system in both physiological and pathological conditions, but the mechanisms controlling its secretion are not completely understood. Here, we show that ARMS/Kidins220 negatively regulates BDNF secretion in neurons from the CNS and PNS. Downregulation of the ARMS/Kidins220 protein in the adult mouse brain increases regulated BDNF secretion, leading to its accumulation in the striatum. Interestingly, two mouse models of Huntington's disease (HD) showed increased levels of ARMS/Kidins220 in the hippocampus and regulated BDNF secretion deficits. Importantly, reduction of ARMS/Kidins220 in hippocampal slices from HD mice reversed the impaired regulated BDNF release. Moreover, there are increased levels of ARMS/Kidins220 in the hippocampus and PFC of patients with HD. ARMS/Kidins220 regulates Synaptotagmin-IV levels, which has been previously observed to modulate BDNF secretion. These data indicate that ARMS/Kidins220 controls the regulated secretion of BDNF and might play a crucial role in the pathogenesis of HD.SIGNIFICANCE STATEMENT BDNF is an important growth factor that plays a fundamental role in the correct functioning of the CNS. The secretion of BDNF must be properly controlled to exert its functions, but the proteins regulating its release are not completely known. Using neuronal cultures and a new conditional mouse to modulate ARMS/Kidins220 protein, we report that ARMS/Kidins220 negatively regulates BDNF secretion. Moreover, ARMS/Kidins220 is overexpressed in two mouse models of Huntington's disease (HD), causing an impaired regulation of BDNF secretion. Furthermore, ARMS/Kidins220 levels are increased in brain samples from HD patients. Future studies should address whether ARMS/Kidins220 has any function on the pathophysiology of HD.
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Kaelberer MM, Bohórquez DV. The now and then of gut-brain signaling. Brain Res 2018; 1693:192-196. [PMID: 29580839 DOI: 10.1016/j.brainres.2018.03.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 01/06/2023]
Abstract
Since their very beginnings, animals had gut sensory epithelial cells. In one of the first multicellular animals, Trichoplax - a literal wandering gut - food sensing and feeding was coordinated by specialized ventral sensor cells. In mammals, including humans, gut epithelial sensor cells (a.k.a enteroendocrine cells) have been recognized for an array of neuropeptides, like ghrelin and cholecystokinin, that modulate hunger or satiety. Indeed, since first described as "clear cells" by Rudfolf Heidenhain (1868), research efforts increasingly focused on their hormone neuropeptides leading to the alphabetical classification of one cell-one hormone (e.g. I-cell synthesizes only cholecystokinin). A recent explosion of molecular tools to study the biology of single cells is expanding the imagination of studies and unveiling intriguing aspects of gut sensory transduction. To mention a few: multimodal sensing, one cell expressing both ghrelin and cholecystokinin-the yin and yang of appetite-, and synapses with nerves. This brief account examines recent advances on gut sensory transduction to highlight how food and bacteria in the gut alter eating.
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Affiliation(s)
- Melanie M Kaelberer
- Division of Gastroenterology, Department of Medicine, Duke University, #221A, Medical Sciences Research Building 1, 203 Research Drive, Durham, NC, USA
| | - Diego V Bohórquez
- Division of Gastroenterology, Department of Medicine, Duke University, #221A, Medical Sciences Research Building 1, 203 Research Drive, Durham, NC, USA; Department of Neurobiology, Duke University, #221A, Medical Sciences Research Building 1, 203 Research Drive, Durham, NC, USA.
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28
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Engelbrechtsen L, Mahendran Y, Jonsson A, Gjesing AP, Weeke PE, Jørgensen ME, Færch K, Witte DR, Holst JJ, Jørgensen T, Grarup N, Pedersen O, Vestergaard H, Torekov S, Kanters JK, Hansen T. Common variants in the hERG (KCNH2) voltage-gated potassium channel are associated with altered fasting and glucose-stimulated plasma incretin and glucagon responses. BMC Genet 2018; 19:15. [PMID: 29548277 PMCID: PMC5857134 DOI: 10.1186/s12863-018-0602-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 03/13/2018] [Indexed: 01/29/2023] Open
Abstract
Background Patients with long QT syndrome due to rare loss-of-function mutations in the human ether-á-go-go-related gene (hERG) have prolonged QT interval, risk of arrhythmias, increased secretion of insulin and incretins and impaired glucagon response to hypoglycemia. This is caused by a dysfunctional Kv11.1 voltage-gated potassium channel. Based on these findings in patients with rare variants in hERG, we hypothesized that common variants in hERG may also lead to alterations in glucose homeostasis. Subsequently, we aimed to evaluate the effect of two common gain-of-function variants in hERG (rs36210421 and rs1805123) on QT interval and plasma levels of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), insulin and glucagon during an oral glucose tolerance test (OGTT). We used two population-based cohorts for evaluation of the effect of common variants in hERG on QT-interval and circulation levels of incretins, insulin and glucagon. The Danish population-based Inter99 cohort (n = 5895) was used to assess the effect of common variants on QT-interval. The Danish ADDITION-PRO cohort was used (n = 1329) to study genetic associations with levels of GLP-1, GIP, insulin and glucagon during an OGTT. Results Carriers of either the minor A-allele of rs36210421 or the minor G-allele of rs1805123 had ~ 2 ms shorter QT interval per risk allele (p = 0.025 and p = 1.9 × 10− 7). Additionally, both variants were associated with alterations in pancreatic and gut hormone release among carriers. The minor A- allele of rs36210421 was associated with increased GLP-1 and decreased GIP response to oral glucose stimulation, whereas the minor G-allele of rs1805123 is associated with decreased fasting plasma insulin and glucagon release. A genetic risk score combining the two gene variants revealed reductions in glucose-stimulated GIP, as well as suppressed glucagon response to increased glucose levels during an OGTT. Conclusions Two common missense polymorphisms of the Kv11.1 voltage-gated hERG potassium channel are associated with alterations in circulating levels of GIP and glucagon, suggesting that hERG potassium channels play a role in fasting and glucose-stimulated release of GIP and glucagon. Trial registration ClinicalTrials.gov (NCT00289237). Trial retrospectively registered at February 9, 2006. Studies were approved by the Ethical Committee of the Central Denmark Region (journal no. 20080229) and by the Copenhagen County Ethical Committee (KA 98155). Electronic supplementary material The online version of this article (10.1186/s12863-018-0602-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Line Engelbrechtsen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark. .,Danish Diabetes Academy, Odense, Denmark.
| | - Yuvaraj Mahendran
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark.,Danish Diabetes Academy, Odense, Denmark
| | - Anna Jonsson
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark
| | - Anette Prior Gjesing
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark
| | - Peter E Weeke
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
| | - Marit E Jørgensen
- National Institute of Public Health, University of Southern Denmark, Odense, Denmark.,Steno Diabetes Center, Gentofte, Denmark
| | | | - Daniel R Witte
- Section of General Practice, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Torben Jørgensen
- Research Centre for Prevention and Health, The Capital Region of Denmark, Hillerød, Denmark.,Department of Public health, Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark.,Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - Niels Grarup
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark
| | - Oluf Pedersen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark
| | - Henrik Vestergaard
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark.,Steno Diabetes Center, Gentofte, Denmark
| | - Signe Torekov
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen K Kanters
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Torben Hansen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, Maersk Tower 8. floor, -2200, Copenhagen, DK, Denmark
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Sodium channel Na V1.3 is important for enterochromaffin cell excitability and serotonin release. Sci Rep 2017; 7:15650. [PMID: 29142310 PMCID: PMC5688111 DOI: 10.1038/s41598-017-15834-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 11/01/2017] [Indexed: 12/28/2022] Open
Abstract
In the gastrointestinal (GI) epithelium, enterochromaffin (EC) cells are enteroendocrine cells responsible for producing >90% of the body's serotonin (5-hydroxytryptamine, 5-HT). However, the molecular mechanisms of EC cell function are poorly understood. Here, we found that EC cells in mouse primary cultures fired spontaneous bursts of action potentials. We examined the repertoire of voltage-gated sodium channels (NaV) in fluorescence-sorted mouse EC cells and found that Scn3a was highly expressed. Scn3a-encoded NaV1.3 was specifically and densely expressed at the basal side of both human and mouse EC cells. Using electrophysiology, we found that EC cells expressed robust NaV1.3 currents, as determined by their biophysical and pharmacologic properties. NaV1.3 was not only critical for generating action potentials in EC cells, but it was also important for regulating 5-HT release by these cells. Therefore, EC cells use Scn3a-encoded voltage-gated sodium channel NaV1.3 for electrical excitability and 5-HT release. NaV1.3-dependent electrical excitability and its contribution to 5-HT release is a novel mechanism of EC cell function.
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Goldspink DA, Lu VB, Billing LJ, Larraufie P, Tolhurst G, Gribble FM, Reimann F. Mechanistic insights into the detection of free fatty and bile acids by ileal glucagon-like peptide-1 secreting cells. Mol Metab 2017; 7:90-101. [PMID: 29167062 PMCID: PMC5784317 DOI: 10.1016/j.molmet.2017.11.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/04/2017] [Accepted: 11/06/2017] [Indexed: 02/07/2023] Open
Abstract
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 signaling pathways recruited following activation of the Gαq-coupled free fatty acid receptors FFA1 and Gαs-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 depolarizing 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. Organoid-derived ileal L-cells recapitulate the properties of primary ileal L-cells. GPBAR1 agonism stimulates L-type Ca2+ current-dependent action potentials in L-cells. FFA1 agonists depolarize L-cells via TRPC3 activation. Synergy between GPBAR1/FFA1 occurs at the levels of Ca2+ responses and secretion.
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Affiliation(s)
- Deborah A Goldspink
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Van B Lu
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Lawrence J Billing
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Pierre Larraufie
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Gwen Tolhurst
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Fiona M Gribble
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
| | - Frank Reimann
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
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Chimerel C, Riccio C, Murison K, Gribble FM, Reimann F. Optogenetic Analysis of Depolarization-Dependent Glucagonlike Peptide-1 Release. Endocrinology 2017; 158:3426-3434. [PMID: 28938466 PMCID: PMC5659701 DOI: 10.1210/en.2017-00434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/25/2017] [Indexed: 12/21/2022]
Abstract
Incretin hormones play an important role in the regulation of food intake and glucose homeostasis. Glucagonlike peptide-1 (GLP-1)-secreting cells have been demonstrated to be electrically excitable and to fire action potentials (APs) with increased frequency in response to nutrient exposure. However, nutrients can also be metabolized or activate G-protein-coupled receptors, thus potentially stimulating GLP-1 secretion independent of their effects on the plasma membrane potential. Here we used channelrhodopsins to manipulate the membrane potential of GLUTag cells, a well-established model of GLP-1-secreting enteroendocrine L cells. Using channelrhodopsins with fast or slow on/off kinetics (CheTA and SSFO, respectively), we found that trains of light pulses could trigger APs and calcium elevation in GLUTag cells stably expressing either CheTA or SSFO. Tetrodotoxin reduced light-triggered AP frequency but did not impair calcium responses, whereas further addition of the calcium-channel blockers nifedipine and ω-conotoxin GVIA abolished both APs and calcium transients. Light pulse trains did not trigger GLP-1 secretion from CheTA-expressing cells under basal conditions but were an effective stimulus when cyclic adenosine monophosphate (cAMP) concentrations were elevated by forskolin plus 3-isobutyl 1-methylxanthine. In SSFO-expressing cells, light-stimulated GLP-1 release was observed at resting and elevated cAMP concentrations and was blocked by nifedipine plus ω-conotoxin GVIA but not tetrodotoxin. We conclude that cAMP elevation or cumulative membrane depolarization triggered by SSFO enhances the efficiency of light-triggered action potential firing, voltage-gated calcium entry, and GLP-1 secretion.
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Affiliation(s)
- Catalin Chimerel
- Metabolic Research Laboratories and Medical Research Council (MRC) Metabolic Diseases Unit, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Cristian Riccio
- Metabolic Research Laboratories and Medical Research Council (MRC) Metabolic Diseases Unit, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Keir Murison
- Metabolic Research Laboratories and Medical Research Council (MRC) Metabolic Diseases Unit, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Fiona M. Gribble
- Metabolic Research Laboratories and Medical Research Council (MRC) Metabolic Diseases Unit, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Frank Reimann
- Metabolic Research Laboratories and Medical Research Council (MRC) Metabolic Diseases Unit, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
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Sun EW, de Fontgalland D, Rabbitt P, Hollington P, Sposato L, Due SL, Wattchow DA, Rayner CK, Deane AM, Young RL, Keating DJ. Mechanisms Controlling Glucose-Induced GLP-1 Secretion in Human Small Intestine. Diabetes 2017; 66:2144-2149. [PMID: 28385801 PMCID: PMC5860185 DOI: 10.2337/db17-0058] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/12/2017] [Indexed: 12/25/2022]
Abstract
Intestinal glucose stimulates secretion of the incretin hormone glucagon-like peptide 1 (GLP-1). The mechanisms underlying this pathway have not been fully investigated in humans. In this study, we showed that a 30-min intraduodenal glucose infusion activated half of all duodenal L cells in humans. This infusion was sufficient to increase plasma GLP-1 levels. With an ex vivo model using human gut tissue specimens, we showed a dose-responsive GLP-1 secretion in the ileum at ≥200 mmol/L glucose. In ex vivo tissue from the duodenum and ileum, but not the colon, 300 mmol/L glucose potently stimulated GLP-1 release. In the ileum, this response was independent of osmotic influences and required delivery of glucose via GLUT2 and mitochondrial metabolism. The requirement of voltage-gated Na+ and Ca2+ channel activation indicates that membrane depolarization occurs. KATP channels do not drive this, as tolbutamide did not trigger release. The sodium-glucose cotransporter 1 (SGLT1) substrate α-MG induced secretion, and the response was blocked by the SGLT1 inhibitor phlorizin or by replacement of extracellular Na+ with N-methyl-d-glucamine. This is the first report of the mechanisms underlying glucose-induced GLP-1 secretion from human small intestine. Our findings demonstrate a dominant role of SGLT1 in controlling glucose-stimulated GLP-1 release in human ileal L cells.
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Affiliation(s)
- Emily W Sun
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | - Dayan de Fontgalland
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Philippa Rabbitt
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Paul Hollington
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Luigi Sposato
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Steven L Due
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - David A Wattchow
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Christopher K Rayner
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Adam M Deane
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Intensive Care Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Richard L Young
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Damien J Keating
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
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Signalling in the gut endocrine axis. Physiol Behav 2017; 176:183-188. [DOI: 10.1016/j.physbeh.2017.02.039] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/23/2017] [Accepted: 02/27/2017] [Indexed: 02/06/2023]
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Bellono NW, Bayrer JR, Leitch DB, Castro J, Zhang C, O'Donnell TA, Brierley SM, Ingraham HA, Julius D. Enterochromaffin Cells Are Gut Chemosensors that Couple to Sensory Neural Pathways. Cell 2017; 170. [PMID: 28648659 PMCID: PMC5839326 DOI: 10.1016/j.cell.2017.05.034] [Citation(s) in RCA: 478] [Impact Index Per Article: 68.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Dietary, microbial, and inflammatory factors modulate the gut-brain axis and influence physiological processes ranging from metabolism to cognition. The gut epithelium is a principal site for detecting such agents, but precisely how it communicates with neural elements is poorly understood. Serotonergic enterochromaffin (EC) cells are proposed to fulfill this role by acting as chemosensors, but understanding how these rare and unique cell types transduce chemosensory information to the nervous system has been hampered by their paucity and inaccessibility to single-cell measurements. Here, we circumvent this limitation by exploiting cultured intestinal organoids together with single-cell measurements to elucidate intrinsic biophysical, pharmacological, and genetic properties of EC cells. We show that EC cells express specific chemosensory receptors, are electrically excitable, and modulate serotonin-sensitive primary afferent nerve fibers via synaptic connections, enabling them to detect and transduce environmental, metabolic, and homeostatic information from the gut directly to the nervous system.
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Affiliation(s)
- Nicholas W Bellono
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - James R Bayrer
- Department of Pediatrics, Division of Gastroenterology, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Duncan B Leitch
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Joel Castro
- Visceral Pain Group, Flinders University, Bedford Park, SA 5042, Australia; Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, SA 5000, Australia
| | - Chuchu Zhang
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Tracey A O'Donnell
- Visceral Pain Group, Flinders University, Bedford Park, SA 5042, Australia; Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, SA 5000, Australia
| | - Stuart M Brierley
- Visceral Pain Group, Flinders University, Bedford Park, SA 5042, Australia; Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, SA 5000, Australia
| | - Holly A Ingraham
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA.
| | - David Julius
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA.
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Psichas A, Tolhurst G, Brighton CA, Gribble FM, Reimann F. Mixed Primary Cultures of Murine Small Intestine Intended for the Study of Gut Hormone Secretion and Live Cell Imaging of Enteroendocrine Cells. J Vis Exp 2017. [PMID: 28448057 PMCID: PMC5409300 DOI: 10.3791/55687] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The gut is the largest endocrine organ of the body, with hormone-secreting enteroendocrine cells located along the length of the gastrointestinal epithelium. Despite their physiological importance, enteroendocrine cells represent only a small fraction of the epithelial cell population and in the past, their characterization has presented a considerable challenge resulting in a reliance on cell line models. Here, we provide a detailed protocol for the isolation and culture of mixed murine small intestinal cells. These primary cultures have been used to identify the signaling pathways underlying the stimulation and inhibition of gut peptide secretion in response to a number of nutrients and neuropeptides as well as pharmacological agents. Furthermore, in combination with the use of transgenic fluorescent reporter mice, we have demonstrated that these primary cultures become a powerful tool for the examination of fluorescently-tagged enteroendocrine cells at the intracellular level, using methods such as patch clamping and single-cell calcium and cAMP-FRET imaging.
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Affiliation(s)
- Arianna Psichas
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge
| | - Gwen Tolhurst
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge
| | - Cheryl A Brighton
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge
| | - Fiona M Gribble
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge;
| | - Frank Reimann
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge;
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Hyltén-Cavallius L, Iepsen EW, Wewer Albrechtsen NJ, Svendstrup M, Lubberding AF, Hartmann B, Jespersen T, Linneberg A, Christiansen M, Vestergaard H, Pedersen O, Holst JJ, Kanters JK, Hansen T, Torekov SS. Patients With Long-QT Syndrome Caused by Impaired hERG-Encoded K v11.1 Potassium Channel Have Exaggerated Endocrine Pancreatic and Incretin Function Associated With Reactive Hypoglycemia. Circulation 2017; 135:1705-1719. [PMID: 28235848 PMCID: PMC5412733 DOI: 10.1161/circulationaha.116.024279] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 02/14/2017] [Indexed: 11/23/2022]
Abstract
Supplemental Digital Content is available in the text. Background: Loss-of-function mutations in hERG (encoding the Kv11.1 voltage-gated potassium channel) cause long-QT syndrome type 2 (LQT2) because of prolonged cardiac repolarization. However, Kv11.1 is also present in pancreatic α and β cells and intestinal L and K cells, secreting glucagon, insulin, and the incretins glucagon-like peptide-1 (GLP-1) and GIP (glucose-dependent insulinotropic polypeptide), respectively. These hormones are crucial for glucose regulation, and long-QT syndrome may cause disturbed glucose regulation. We measured secretion of these hormones and cardiac repolarization in response to glucose ingestion in LQT2 patients with functional mutations in hERG and matched healthy participants, testing the hypothesis that LQT2 patients have increased incretin and β-cell function and decreased α-cell function, and thus lower glucose levels. Methods: Eleven patients with LQT2 and 22 sex-, age-, and body mass index–matched control participants underwent a 6-hour 75-g oral glucose tolerance test with ECG recording and blood sampling for measurements of glucose, insulin, C-peptide, glucagon, GLP-1, and GIP. Results: In comparison with matched control participants, LQT2 patients had 56% to 78% increased serum insulin, serum C-peptide, plasma GLP-1, and plasma GIP responses (P=0.03–0.001) and decreased plasma glucose levels after glucose ingestion (P=0.02) with more symptoms of hypoglycemia (P=0.04). Sixty-three percent of LQT2 patients developed hypoglycemic plasma glucose levels (<70 mg/dL) versus 36% control participants (P=0.16), and 18% patients developed serious hypoglycemia (<50 mg/dL) versus none of the controls. LQT2 patients had defective glucagon responses to low glucose, P=0.008. β-Cell function (Insulin Secretion Sensitivity Index-2) was 2-fold higher in LQT2 patients than in controls (4398 [95% confidence interval, 2259–8562] versus 2156 [1961–3201], P=0.03). Pharmacological Kv11.1 blockade (dofetilide) in rats had similar effect, and small interfering RNA inhibition of hERG in β and L cells increased insulin and GLP-1 secretion up to 50%. Glucose ingestion caused cardiac repolarization disturbances with increased QTc intervals in both patients and controls, but with a 122% greater increase in QTcF interval in LQT2 patients (P=0.004). Conclusions: Besides a prolonged cardiac repolarization phase, LQT2 patients display increased GLP-1, GIP, and insulin secretion and defective glucagon secretion, causing decreased plasma glucose and thus increased risk of hypoglycemia. Furthermore, glucose ingestion increased QT interval and aggravated the cardiac repolarization disturbances in LQT2 patients. Clinical Trial Registration: URL: http://clinicaltrials.gov. Unique identifier: NCT02775513.
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Affiliation(s)
- Louise Hyltén-Cavallius
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Eva W Iepsen
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Nicolai J Wewer Albrechtsen
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Mathilde Svendstrup
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Anniek F Lubberding
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Bolette Hartmann
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Thomas Jespersen
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Allan Linneberg
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Michael Christiansen
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Henrik Vestergaard
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Oluf Pedersen
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Jens J Holst
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Jørgen K Kanters
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.)
| | - Torben Hansen
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.).
| | - Signe S Torekov
- From Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., A.F.L., B.H., T.J., M.C., J.J.H., J.K.K., S.S.T.); Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (L.H.-C., E.W.I., N.J.W.A., M.S., B.H., H.V., O.P., J.J.H., T.H., S.S.T.); Research Centre for Prevention and Health, the Capital Region of Denmark, Copenhagen (A.L.); Gentofte, Aalborg and Herlev University Hospitals, Denmark (J.K.K.); Faculty of Health Sciences, University of Southern Denmark, Odense (T.H.); Department of Clinical Experimental Research, Rigshospitalet, Denmark (A.L.); Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (A.L.); Danish Diabetes Academy, Odense, Denmark (E.W.I., M.S.); Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C.); and Steno Diabetes Center Copenhagen, Gentofte, Denmark (H.V.).
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Tagliavini A, Pedersen MG. Spatiotemporal Modeling of Triggering and Amplifying Pathways in GLP-1 Secreting Intestinal L Cells. Biophys J 2017; 112:162-171. [PMID: 28076808 PMCID: PMC5232896 DOI: 10.1016/j.bpj.2016.11.3199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/16/2016] [Accepted: 11/29/2016] [Indexed: 01/06/2023] Open
Abstract
Glucagon-like peptide 1 (GLP-1) is secreted by intestinal L-cells, and augments glucose-induced insulin secretion, thus playing an important role in glucose control. The stimulus-secretion pathway in L-cells is still incompletely understood and a topic of debate. It is known that GLP-1 secreting cells can sense glucose to promote electrical activity either by the electrogenic sodium-glucose cotransporter SGLT1, or by closure of ATP-sensitive potassium channels after glucose metabolism. Glucose also has an effect on GLP-1 secretion downstream of electrical activity. An important aspect to take into account is the spatial organization of the cell. Indeed, the glucose transporter GLUT2 is located at the basolateral, vascular side, while SGLT1 is exposed to luminal glucose at the apical side of the cell, suggesting that the two types of transporters play different roles in glucose sensing. Here, we extend our recent model of electrical activity in primary L-cells to include spatiotemporal glucose and Ca2+ dynamics, and GLP-1 secretion. The model confirmed that glucose transportation into the cell through SGLT1 cotransporters can induce Ca2+ influx and release of GLP-1 as a result of electrical activity, while glucose metabolism alone is insufficient to depolarize the cell and evoke GLP-1 secretion in the model, suggesting a crucial role for SGLT1 in triggering GLP-1 release in agreement with experimental studies. We suggest a secondary, but participating, role of GLUT2 and glucose metabolism for GLP-1 secretion via an amplifying pathway that increases the secretion rate at a given Ca2+ level.
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Affiliation(s)
- Alessia Tagliavini
- Department of Information Engineering, University of Padova, Padova, Italy
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Pais R, Rievaj J, Larraufie P, Gribble F, Reimann F. Angiotensin II Type 1 Receptor-Dependent GLP-1 and PYY Secretion in Mice and Humans. Endocrinology 2016; 157:3821-3831. [PMID: 27447725 PMCID: PMC5045501 DOI: 10.1210/en.2016-1384] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Angiotensin II (Ang II) is the key hormone mediator of the renin angiotensin system, which regulates blood pressure and fluid and electrolyte balance in the body. Here we report that in the colonic epithelium, the Ang II type 1 receptor is highly and exclusively expressed in enteroendocrine L cells, which produce the gut hormones glucagon-like peptide-1 and peptide YY (PYY). Ang II stimulated glucagon-like peptide-1 and PYY release from primary cultures of mouse and human colon, which was antagonized by the specific Ang II type 1 receptor blocker candesartan. Ang II raised intracellular calcium levels in L cells in primary cultures, recorded by live-cell imaging of L cells specifically expressing the fluorescent calcium sensor GCaMP3. In Ussing chamber recordings, Ang II reduced short circuit currents in mouse distal colon preparations, which was antagonized by candesartan or a specific neuropeptide Y1 receptor inhibitor but insensitive to amiloride. We conclude that Ang II stimulates PYY secretion, in turn inhibiting epithelial anion fluxes, thereby reducing net fluid secretion into the colonic lumen. Our findings highlight an important role of colonic L cells in whole-body fluid homeostasis by controlling water loss through the intestine.
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Affiliation(s)
- Ramona Pais
- Wellcome Trust-Medical Research Council Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
| | - Juraj Rievaj
- Wellcome Trust-Medical Research Council Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
| | - Pierre Larraufie
- Wellcome Trust-Medical Research Council Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
| | - Fiona Gribble
- Wellcome Trust-Medical Research Council Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
| | - Frank Reimann
- Wellcome Trust-Medical Research Council Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
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Chepurny OG, Leech CA, Tomanik M, DiPoto MC, Li H, Han X, Meng Q, Cooney RN, Wu J, Holz GG. Synthetic small molecule GLP-1 secretagogues prepared by means of a three-component indole annulation strategy. Sci Rep 2016; 6:28934. [PMID: 27352904 PMCID: PMC4926213 DOI: 10.1038/srep28934] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 06/13/2016] [Indexed: 12/14/2022] Open
Abstract
Rational assembly of small molecule libraries for purposes of drug discovery requires an efficient approach in which the synthesis of bioactive compounds is enabled so that numerous structurally related compounds of a similar basic formulation can be derived. Here, we describe (4 + 3) and (3 + 2) indole annulation strategies that quickly generate complex indole heterocycle libraries that contain novel cyclohepta- and cyclopenta[b]indoles, respectively. Screening of one such library comprised of these indoles identifies JWU-A021 to be an especially potent stimulator of glucagon-like peptide-1 (GLP-1) secretion in vitro. Surprisingly, JWU-A021 is also a potent stimulator of Ca2+ influx through TRPA1 cation channels (EC50ca. 200 nM), thereby explaining its ability to stimulate GLP-1 release. Of additional importance, the available evidence indicates that JWU-A021 is one of the most potent non-electrophilic TRPA-1 channel agonists yet to be reported in the literature.
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Affiliation(s)
- Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Colin A Leech
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Martin Tomanik
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA
| | - Maria C DiPoto
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA
| | - Hui Li
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA
| | - Xinping Han
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA
| | - Qinghe Meng
- Department of Surgery, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Robert N Cooney
- Department of Surgery, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Jimmy Wu
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA
| | - George G Holz
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA.,Department of Pharmacology, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
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40
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Altenhofen D, da Luz G, Frederico MJS, Venzke D, Brich M, Vigil S, Fröde TS, Linares CEB, Pizzolatti MG, Silva FRMB. Bis-Pyrano Prenyl Isoflavone Improves Glucose Homeostasis by Inhibiting Dipeptidyl Peptidase-4 in Hyperglycemic Rats. J Cell Biochem 2016; 118:92-103. [PMID: 27238050 DOI: 10.1002/jcb.25614] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 05/26/2016] [Indexed: 12/25/2022]
Abstract
Isoflavones widely distributed in plants prevent diabetes. This study investigated the in vivo and in vitro effect of 3',4'-dihydroxy-6″,6″,6″',6″'-tetramethylbis(pyrano[2″,3″:5,6::2″',3″':7,8]isoflavone (bis-pyrano prenyl isoflavone) on glucose homeostasis in hyperglycemic rats. The ethyl acetate fraction from aerial parts of Polygala molluginifolia that contain isoflavones was assayed on glucose tolerance, on in vitro maltase activity and on protein glycation. The isoflavone bis-pyrano prenyl isolated from this fraction was investigated on glucose homeostasis. The in vivo action of the isoflavone exhibits an anti-hyperglycemic effect by improving glucose tolerance, augmenting the liver glycogen, inhibiting maltase activity, and stimulating glucagon-like peptide-1 (GLP-1) and insulin secretion. The in vitro isoflavone inhibits dipeptidyl peptidase-4 (DPP-4) activity since the glucose tolerance was improved in the presence of the isoflavone as much as sitagliptin, an inhibitor of DPP-4. However, the co-incubation with isoflavone and sitagliptin exhibited an additive anti-hyperglycemic action. The isoflavone increased the GLP-1 faster than the positive hyperglycemic group, which shows that the intestine is a potential target. Thus, to clarify the main site of action in which isoflavone improves glucose balance, the in vitro mechanism of action of this compound was tested in intestine using calcium influx as a trigger for the signal pathways for GLP-1 secretion. The isoflavone stimulates calcium influx in intestine and its mechanism involves voltage-dependent calcium channels, phospholipase C, protein kinase C, and stored calcium contributing for GLP-1 secretion. In conclusion, the isoflavone regulates glycaemia by acting mainly in a serum target, the DPP-4 inhibitor. Furthermore, the long-term effect of isoflavone prevents protein glycation. J. Cell. Biochem. 118: 92-103, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Delsi Altenhofen
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Cx. Postal 5069, CEP: 88040-970, Florianópolis, Santa Catarina, Brazil
| | - Gabrielle da Luz
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Cx. Postal 5069, CEP: 88040-970, Florianópolis, Santa Catarina, Brazil
| | - Marisa Jádna Silva Frederico
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Cx. Postal 5069, CEP: 88040-970, Florianópolis, Santa Catarina, Brazil
| | - Dalila Venzke
- Departamento de Química, Centro de Ciências Físicas e Matemáticas, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, CEP: 88040-900, Florianópolis, Santa Catarina, Brazil
| | - Mayara Brich
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Cx. Postal 5069, CEP: 88040-970, Florianópolis, Santa Catarina, Brazil
| | - Silvana Vigil
- Departamento de Análises Clínicas, Centro de Ciências da Saúde, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, CEP: 88040-900, Florianópolis, Santa Catarina, Brazil
| | - Tania Silvia Fröde
- Departamento de Análises Clínicas, Centro de Ciências da Saúde, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, CEP: 88040-900, Florianópolis, Santa Catarina, Brazil
| | - Carlos Eduardo Blanco Linares
- Departamento de Ciências da Saúde, Centro de Ciências da Saúde, Universidade Regional Integrada do Alto Uruguai e da Missões, Campus Frederico Westphalen, Frederico Westphalen, Rio Grande do Sul, Brazil
| | - Moacir Geraldo Pizzolatti
- Departamento de Química, Centro de Ciências Físicas e Matemáticas, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, CEP: 88040-900, Florianópolis, Santa Catarina, Brazil
| | - Fátima Regina Mena Barreto Silva
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Cx. Postal 5069, CEP: 88040-970, Florianópolis, Santa Catarina, Brazil
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41
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Abstract
Glucagon like peptide-1 is an insulinotropic hormone released from intestinal L-cells in response to food ingestion. Here, we investigated mechanisms underlying the sensing of peptones by primary small intestinal L-cells. Meat, casein and vegetable-derived peptones (5 mg/ml), the L-amino acids Phe, Trp, Gln and Ala (20 mM each), and the dipeptide glycine-sarcosine (20 mM) stimulated GLP-1 secretion from primary cultures prepared from the small intestine. Further mechanistic studies were performed with meat peptone, and revealed the elevation of intracellular calcium in L-cells. Inhibition of the calcium sensing receptor (CaSR), transient receptor potential (TRP) channels and Q-type voltage gated calcium channels (VGCC) significantly attenuated peptone-stimulated GLP-1 release and reduced intracellular Ca(2+) responses. CaSR inhibition also attenuated the GLP-1 secretory response to Gln. Targeting these pathways in L-cells could be used to increase endogenous production of GLP-1 and offer exploitable avenues for the development of therapeutics to treat diabetes and obesity.
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Affiliation(s)
- Ramona Pais
- Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Fiona M Gribble
- Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK.
| | - Frank Reimann
- Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK.
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42
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Riz M, Pedersen MG. Mathematical Modeling of Interacting Glucose-Sensing Mechanisms and Electrical Activity Underlying Glucagon-Like Peptide 1 Secretion. PLoS Comput Biol 2015; 11:e1004600. [PMID: 26630068 PMCID: PMC4667885 DOI: 10.1371/journal.pcbi.1004600] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 10/13/2015] [Indexed: 01/12/2023] Open
Abstract
Intestinal L-cells sense glucose and other nutrients, and in response release glucagon-like peptide 1 (GLP-1), peptide YY and other hormones with anti-diabetic and weight-reducing effects. The stimulus-secretion pathway in L-cells is still poorly understood, although it is known that GLP-1 secreting cells use sodium-glucose co-transporters (SGLT) and ATP-sensitive K+-channels (K(ATP)-channels) to sense intestinal glucose levels. Electrical activity then transduces glucose sensing to Ca2+-stimulated exocytosis. This particular glucose-sensing arrangement with glucose triggering both a depolarizing SGLT current as well as leading to closure of the hyperpolarizing K(ATP) current is of more general interest for our understanding of glucose-sensing cells. To dissect the interactions of these two glucose-sensing mechanisms, we build a mathematical model of electrical activity underlying GLP-1 secretion. Two sets of model parameters are presented: one set represents primary mouse colonic L-cells; the other set is based on data from the GLP-1 secreting GLUTag cell line. The model is then used to obtain insight into the differences in glucose-sensing between primary L-cells and GLUTag cells. Our results illuminate how the two glucose-sensing mechanisms interact, and suggest that the depolarizing effect of SGLT currents is modulated by K(ATP)-channel activity. Based on our simulations, we propose that primary L-cells encode the glucose signal as changes in action potential amplitude, whereas GLUTag cells rely mainly on frequency modulation. The model should be useful for further basic, pharmacological and theoretical investigations of the cellular signals underlying endogenous GLP-1 and peptide YY release.
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Affiliation(s)
- Michela Riz
- Department of Information Engineering, University of Padua, Padua, Italy
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43
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Bohórquez D, Haque F, Medicetty S, Liddle RA. Correlative Confocal and 3D Electron Microscopy of a Specific Sensory Cell. J Vis Exp 2015:e52918. [PMID: 26273796 PMCID: PMC4544857 DOI: 10.3791/52918] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Delineation of a cell's ultrastructure is important for understanding its function. This can be a daunting project for rare cell types diffused throughout tissues made of diverse cell types, such as enteroendocrine cells of the intestinal epithelium. These gastrointestinal sensors of food and bacteria have been difficult to study because they are dispersed among other epithelial cells at a ratio of 1:1,000. Recently, transgenic reporter mice have been generated to identify enteroendocrine cells by means of fluorescence. One of those is the peptide YY-GFP mouse. Using this mouse, we developed a method to correlate confocal and serial block-face scanning electron microscopy. We named the method cocem3D and applied it to identify a specific enteroendocrine cell in tissue and unveil the cell's ultrastructure in 3D. The resolution of cocem3D is sufficient to identify organelles as small as secretory vesicles and to distinguish cell membranes for volume rendering. Cocem3D can be easily adapted to study the 3D ultrastructure of other specific cell types in their native tissue.
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Affiliation(s)
| | - Fariha Haque
- Department of Chemistry, University of North Carolina - Chapel Hill
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44
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Emery EC, Diakogiannaki E, Gentry C, Psichas A, Habib AM, Bevan S, Fischer MJM, Reimann F, Gribble FM. Stimulation of GLP-1 secretion downstream of the ligand-gated ion channel TRPA1. Diabetes 2015; 64:1202-10. [PMID: 25325736 PMCID: PMC4375100 DOI: 10.2337/db14-0737] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Stimulus-coupled incretin secretion from enteroendocrine cells plays a fundamental role in glucose homeostasis and could be targeted for the treatment of type 2 diabetes. Here, we investigated the expression and function of transient receptor potential (TRP) ion channels in enteroendocrine L cells producing GLP-1. By microarray and quantitative PCR analysis, we identified trpa1 as an L cell-enriched transcript in the small intestine. Calcium imaging of primary L cells and the model cell line GLUTag revealed responses triggered by the TRPA1 agonists allyl-isothiocyanate (mustard oil), carvacrol, and polyunsaturated fatty acids, which were blocked by TRPA1 antagonists. Electrophysiology in GLUTag cells showed that carvacrol induced a current with characteristics typical of TRPA1 and triggered the firing of action potentials. TRPA1 activation caused an increase in GLP-1 secretion from primary murine intestinal cultures and GLUTag cells, an effect that was abolished in cultures from trpa1(-/-) mice or by pharmacological TRPA1 inhibition. These findings present TRPA1 as a novel sensory mechanism in enteroendocrine L cells, coupled to the facilitation of GLP-1 release, which may be exploitable as a target for treating diabetes.
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Affiliation(s)
- Edward C Emery
- Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, U.K
| | | | - Clive Gentry
- Wolfson Centre for Age-Related Diseases, King's College London, London, U.K
| | - Arianna Psichas
- Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, U.K
| | - Abdella M Habib
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, U.K
| | - Stuart Bevan
- Wolfson Centre for Age-Related Diseases, King's College London, London, U.K
| | - Michael J M Fischer
- Institute of Physiology and Pathophysiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Frank Reimann
- Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, U.K.
| | - Fiona M Gribble
- Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, U.K.
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45
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Acosta A, Abu Dayyeh BK, Port JD, Camilleri M. Recent advances in clinical practice challenges and opportunities in the management of obesity. Gut 2014; 63:687-95. [PMID: 24402654 PMCID: PMC4170188 DOI: 10.1136/gutjnl-2013-306235] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Despite advances in understanding the roles of adiposity, food intake, GI and adipocyte-related hormones, inflammatory mediators, the gut-brain axis and the hypothalamic nervous system in the pathophysiology of obesity, the effects of different therapeutic interventions on those pathophysiological mechanisms are controversial. There are still no low-cost, safe, effective treatments for obesity and its complications. Currently, bariatric surgical approaches targeting the GI tract are more effective than non-surgical approaches in inducing weight reduction and resolving obesity-related comorbidities. However, current guidelines emphasise non-surgical approaches through lifestyle modification and medications to achieve slow weight loss, which is not usually sustained and may be associated with medication-related side effects. This review analyses current central, peripheral or hormonal targets to treat obesity and addresses challenges and opportunities to develop novel approaches for obesity.
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Affiliation(s)
- Andres Acosta
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Barham K. Abu Dayyeh
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - John D. Port
- Division of Neuroradiology, Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota
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46
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Torekov SS, Iepsen E, Christiansen M, Linneberg A, Pedersen O, Holst JJ, Kanters JK, Hansen T. KCNQ1 long QT syndrome patients have hyperinsulinemia and symptomatic hypoglycemia. Diabetes 2014; 63:1315-25. [PMID: 24357532 DOI: 10.2337/db13-1454] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Patients with loss-of-function mutations in KCNQ1 have KCNQ1 long QT syndrome (LQTS). KCNQ1 encodes a voltage-gated K(+) channel located in both cardiomyocytes and pancreatic β-cells. Inhibition of KCNQ1 in β-cells increases insulin secretion. Therefore KCNQ1 LQTS patients may exhibit increased insulin secretion. Fourteen patients, from six families, diagnosed with KCNQ1 LQTS were individually matched to two randomly chosen BMI-, age-, and sex-matched control participants and underwent an oral glucose tolerance test (OGTT), a hypoglycemia questionnaire, and continuous glucose monitoring. KCNQ1 mutation carriers showed increased insulin release (area under the curve 45.6 ± 6.3 vs. 26.0 ± 2.8 min ⋅ nmol/L insulin) and β-cell glucose sensitivity and had lower levels of plasma glucose and serum potassium upon oral glucose stimulation and increased hypoglycemic symptoms. Prolonged OGTT in four available patients and matched control subjects revealed hypoglycemia in carriers after 210 min (range 1.4-3.6 vs. 4.1-5.3 mmol/L glucose), and 24-h glucose profiles showed that the patients spent 77 ± 18 min per 24 h in hypoglycemic states (<3.9 mmol/L glucose) with 36 ± 10 min (<2.8 mmol/L glucose) vs. 0 min (<3.9 mmol/L glucose) for the control participants. The phenotype of patients with KCNQ1 LQTS, caused by mutations in KCNQ1, includes, besides long QT, hyperinsulinemia, clinically relevant symptomatic reactive hypoglycemia, and low potassium after an oral glucose challenge, suggesting that KCNQ1 mutations may explain some cases of "essential" reactive hypoglycemia.
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Affiliation(s)
- Signe S Torekov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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47
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Bohórquez DV, Samsa LA, Roholt A, Medicetty S, Chandra R, Liddle RA. An enteroendocrine cell-enteric glia connection revealed by 3D electron microscopy. PLoS One 2014; 9:e89881. [PMID: 24587096 PMCID: PMC3935946 DOI: 10.1371/journal.pone.0089881] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 01/28/2014] [Indexed: 11/25/2022] Open
Abstract
The enteroendocrine cell is the cornerstone of gastrointestinal chemosensation. In the intestine and colon, this cell is stimulated by nutrients, tastants that elicit the perception of flavor, and bacterial by-products; and in response, the cell secretes hormones like cholecystokinin and peptide YY – both potent regulators of appetite. The development of transgenic mice with enteroendocrine cells expressing green fluorescent protein has allowed for the elucidation of the apical nutrient sensing mechanisms of the cell. However, the basal secretory aspects of the enteroendocrine cell remain largely unexplored, particularly because a complete account of the enteroendocrine cell ultrastructure does not exist. Today, the fine ultrastructure of a specific cell can be revealed in the third dimension thanks to the invention of serial block face scanning electron microscopy (SBEM). Here, we bridged confocal microscopy with SBEM to identify the enteroendocrine cell of the mouse and study its ultrastructure in the third dimension. The results demonstrated that 73.5% of the peptide-secreting vesicles in the enteroendocrine cell are contained within an axon-like basal process. We called this process a neuropod. This neuropod contains neurofilaments, which are typical structural proteins of axons. Surprisingly, the SBEM data also demonstrated that the enteroendocrine cell neuropod is escorted by enteric glia – the cells that nurture enteric neurons. We extended these structural findings into an in vitro intestinal organoid system, in which the addition of glial derived neurotrophic factors enhanced the development of neuropods in enteroendocrine cells. These findings open a new avenue of exploration in gastrointestinal chemosensation by unveiling an unforeseen physical relationship between enteric glia and enteroendocrine cells.
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Affiliation(s)
- Diego V. Bohórquez
- Departments of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
| | - Leigh A. Samsa
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Andrew Roholt
- Renovo Neural Incorporation, Cleveland, Ohio, United States of America
| | - Satish Medicetty
- Renovo Neural Incorporation, Cleveland, Ohio, United States of America
| | - Rashmi Chandra
- Departments of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Rodger A. Liddle
- Departments of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
- Veterans Affairs Medical Center, Durham, North Carolina, United States of America
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48
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Role of nutrient-sensing taste 1 receptor (T1R) family members in gastrointestinal chemosensing. Br J Nutr 2014; 111 Suppl 1:S8-15. [DOI: 10.1017/s0007114513002286] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Luminal nutrient sensing by G-protein-coupled receptors (GPCR) expressed on the apical domain of enteroendocrine cells activates intracellular pathways leading to secretion of gut hormones that control vital physiological processes such as digestion, absorption, food intake and glucose homeostasis. The taste 1 receptor (T1R) family of GPCR consists of three members: T1R1; T1R2; T1R3. Expression of T1R1, T1R2 and T1R3 at mRNA and protein levels has been demonstrated in the intestinal tissue of various species. It has been shown that T1R2–T1R3, in association with G-protein gustducin, is expressed in intestinal K and L endocrine cells, where it acts as the intestinal glucose (sweet) sensor. A number of studies have demonstrated that activation of T1R2–T1R3 by natural sugars and artificial sweeteners leads to secretion of glucagon-like peptides 1&2 (GLP-1 and GLP-2) and glucose dependent insulinotropic peptide (GIP). GLP-1 and GIP enhance insulin secretion; GLP-2 increases intestinal growth and glucose absorption. T1R1–T1R3 combination co-expressed on the apical domain of cholecystokinin (CCK) expressing cells is a luminal sensor for a number of l-amino acids; with amino acid-activation of the receptor eliciting CCK secretion. This article focuses on the role of the gut-expressed T1R1, T1R2 and T1R3 in intestinal sweet and l-amino acid sensing. The impact of exploiting T1R2–T1R3 as a nutritional target for enhancing intestinal glucose absorption and gut structural maturity in young animals is also highlighted.
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49
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Liu L, Wang F, Lu H, Ren X, Zou J. Chromanol 293B, an inhibitor of KCNQ1 channels, enhances glucose-stimulated insulin secretion and increases glucagon-like peptide-1 level in mice. Islets 2014; 6:e962386. [PMID: 25437377 PMCID: PMC4588556 DOI: 10.4161/19382014.2014.962386] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Glucose-stimulated insulin secretion (GSIS) is a highly regulated process involving complex interaction of multiple factors. Potassium voltage-gated channel subfamily KQT member 1 (KCNQ1) is a susceptibility gene for type 2 diabetes (T2D) and the risk alleles of the KCNQ1 gene appear to be associated with impaired insulin secretion. The role of KCNQ1 channel in insulin secretion has been explored by previous work in clonal pancreatic β-cells but has yet to be investigated in the context of primary islets as well as intact animals. Genetic studies suggest that altered incretin glucagon-like peptide-1 (GLP-1) secretion might be a potential link between KCNQ1 variants and impaired insulin secretion, but this hypothesis has not been verified so far. In the current study, we examined KCNQ1 expression in pancreas and intestine from normal mice and then investigated the effects of chromanol 293B, a KCNQ1 channel inhibitor, on insulin secretion in vitro and in vivo. By double-immunofluorescence staining, KCNQ1 was detected in insulin-positive β-cells and GLP-1-positive L-cells. Administration of chromanol 293B enhanced GSIS in cultured islets and intact animals. Along with the potentiated insulin secretion during oral glucose tolerance tests (OGTT), plasma GLP-1 level after gastric glucose load was increased in 293B treated mice. These data not only provided new evidence for the participation of KCNQ1 in GSIS at the level of pancreatic islet and intact animal but also indicated the potential linking role of GLP-1 between KCNQ1 and insulin secretion.
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Key Words
- AUC, Area under the curve
- DMSO, Dimethyl sulfoxide
- GLP-1
- GLP-1, Glucagon-like peptide-1
- GSIS
- GSIS, Glucose-stimulated insulin secretion
- GTT, Glucose tolerance test
- GWAS, Genome wide association studies
- IPGTT
- ITT
- ITT, Insulin tolerance test
- IVGTT, Intravenous glucose tolerance tests
- KCNQ1
- KCNQ1, Potassium voltage-gated channel subfamily KQT member 1
- KRBH, Krebs-Ringer bicarbonate HEPES buffer
- OCT, Optimal Cutting Temperature Compound
- OGTT
- OGTT, Oral glucose tolerance tests
- SNPs, Single nucleotide polymorphisms
- T2D, Type 2 diabetes
- chromanol 293B
- islets of Langerhans
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Affiliation(s)
- Lijie Liu
- Department of Physiology; Medical College of Southeast University; Nanjing, China
| | - Fanfan Wang
- Institute of Life Sciences; Southeast University; Nanjing, China
| | - Haiying Lu
- Institute of Life Sciences; Southeast University; Nanjing, China
| | - Xiaomei Ren
- Department of Geriatrics; Affiliated ZhongDa Hospital of Southeast University; Nanjing, China
| | - Jihong Zou
- Department of Geriatrics; Affiliated ZhongDa Hospital of Southeast University; Nanjing, China
- Correspondence to: Jihong Zou;
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Enteroendocrine cell types revisited. Curr Opin Pharmacol 2013; 13:912-21. [PMID: 24140256 DOI: 10.1016/j.coph.2013.09.018] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 09/23/2013] [Accepted: 09/23/2013] [Indexed: 02/07/2023]
Abstract
The GI-tract is profoundly involved in the control of metabolism through peptide hormones secreted from enteroendocrine cells scattered throughout the gut mucosa. A large number of recently generated transgenic reporter mice have allowed for direct characterization of biochemical and cell biological properties of these previously highly elusive enteroendocrine cells. In particular the surprisingly broad co-expression of six functionally related hormones in the intestinal enteroendocrine cells indicates that it should be possible to control not only the hormone secretion but also the type and number of enteroendocrine cells. However, this will require a more deep understanding of the factors controlling differentiation, gene expression and specification of the enteroendocrine cells during their weekly renewal from progenitor cells in the crypts of the mucosa.
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