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Dye FS, Larraufie P, Kay R, Darwish T, Rievaj J, Goldspink DA, Meek CL, Middleton SJ, Hardwick RH, Roberts GP, Percival-Alwyn JL, Vaughan T, Ferraro F, Challis BG, O'Rahilly S, Groves M, Gribble FM, Reimann F. Characterisation of proguanylin expressing cells in the intestine - evidence for constitutive luminal secretion. Sci Rep 2019; 9:15574. [PMID: 31666564 PMCID: PMC6821700 DOI: 10.1038/s41598-019-52049-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/10/2019] [Indexed: 12/14/2022] Open
Abstract
Guanylin, a peptide implicated in regulation of intestinal fluid secretion, is expressed in the mucosa, but the exact cellular origin remains controversial. In a new transgenic mouse model fluorescent reporter protein expression driven by the proguanylin promoter was observed throughout the small intestine and colon in goblet and Paneth(-like) cells and, except in duodenum, in mature enterocytes. In Ussing chamber experiments employing both human and mouse intestinal tissue, proguanylin was released predominantly in the luminal direction. Measurements of proguanylin expression and secretion in cell lines and organoids indicated that secretion is largely constitutive and requires ER to Golgi transport but was not acutely regulated by salt or other stimuli. Using a newly-developed proguanylin assay, we found plasma levels to be raised in humans after total gastrectomy or intestinal transplantation, but largely unresponsive to nutrient ingestion. By LC-MS/MS we identified processed forms in tissue and luminal extracts, but in plasma we only detected full-length proguanylin. Our transgenic approach provides information about the cellular origins of proguanylin, complementing previous immunohistochemical and in-situ hybridisation results. The identification of processed forms of proguanylin in the intestinal lumen but not in plasma supports the notion that the primary site of action is the gut itself.
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Affiliation(s)
- Florent Serge Dye
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK.,Department of Antibody Discovery and Protein Engineering, R&D, AstraZeneca, Cambridge, UK
| | - Pierre Larraufie
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Richard Kay
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Tamana Darwish
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Juraj Rievaj
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK.,Dosage Form Design & Development, AstraZeneca, Cambridge, UK
| | - Deborah A Goldspink
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Claire L Meek
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Stephen J Middleton
- Department of Gastroenterology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Richard H Hardwick
- Barrett's Oesophagus and Oesophago-gastric Cancer, Gastroenterology Services, Addenbrooke's Hospital, Cambridge, UK
| | - Geoffrey P Roberts
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | | | - Tris Vaughan
- Department of Antibody Discovery and Protein Engineering, R&D, AstraZeneca, Cambridge, UK
| | - Franco Ferraro
- Department of Antibody Discovery and Protein Engineering, R&D, AstraZeneca, Cambridge, UK
| | - Benjamin G Challis
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Stephen O'Rahilly
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Maria Groves
- Department of Antibody Discovery and Protein Engineering, R&D, AstraZeneca, Cambridge, UK.
| | - Fiona M Gribble
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Frank Reimann
- Wellcome/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK.
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