title: Duodenal CCK cells from male mice express multiple hormones including ghrelin.
abstract: Enteroendocrine (EEC) cells have a pivotal role in intestinal nutrient sensing and release hormones that orchestrate food digestion and regulate appetite. EEC cells are found scattered throughout the intestine and have typically been classified based on the primary hormone they contain. I cells represent a subset of EEC cells that secrete cholecystokinin (CCK) and are mainly localized to the duodenum. Recent studies have shown that I cells express mRNAs encoding several gut hormones. In this study, we investigated the hormonal profile of murine fluorescence-activated cell sorting-sorted duodenal I cells using semiquantitative RT-PCR, liquid chromatography tandem mass spectrometry, and immunostaining methods. We report that I cells are enriched in mRNA transcripts encoding CCK and also other key gut hormones, including neurotensin, glucose-dependent insulinotropic peptide (GIP), secretin, peptide YY, proglucagon, and ghrelin (Ghrl). Furthermore, liquid chromatography tandem mass spectrometry analysis of fluorescence-activated cell sorting-purified I cells and immunostaining confirmed the presence of these gut hormones in duodenal I cells. Immunostaining highlighted that subsets of I cells in both crypts and villi coexpress differential amounts of CCK, Ghrl, GIP, or peptide YY, indicating that a proportion of I cells contain several hormones during maturation and when fully differentiated. Our results reveal that although I cells express several key gut hormones, including GIP or proglucagon, and thus have a considerable overlap with classically defined K and L cells, approximately half express Ghrl, suggesting a potentially important subset of duodenal EEC cells that require further consideration.
authors.affiliation: Faculty of Life Sciences (A.G.S., C.D., C.P.S.) and School of Medicine (J.T.M.), The University of Manchester, Manchester, M13 9PT United Kingdom; Department of Biomedicine (L.C., T.P., R.A.F.), InterPrET Center and Membranes, Aarhus University, Aarhus, DK-800 Denmark; Faculty of Medicine (T.P.), Chulalongkorn University, Bangkok, 10330 Thailand; and Graduate Program Molecular Basis of Human Diseases (A.G.S.), University of Crete Medical School, 71003 Iraklion, Crete, Greece.
authors.forename: Alexandros G
authors.initials: AG
authors.lastname: Sykaras
authors.forename: Claire
authors.initials: C
authors.lastname: Demenis
authors.forename: Lei
authors.initials: L
authors.lastname: Cheng
authors.forename: Trairak
authors.initials: T
authors.lastname: Pisitkun
authors.forename: John T
authors.initials: JT
authors.lastname: Mclaughlin
authors.forename: Robert A
authors.initials: RA
authors.lastname: Fenton
authors.forename: Craig P
authors.initials: CP
authors.lastname: Smith
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002766:Cholecystokinin / Q000235:genetics / Q000378:metabolism*; D004386:Duodenum / Q000166:cytology / Q000378:metabolism*; D019858:Enteroendocrine Cells / Q000166:cytology / Q000378:metabolism*; D005434:Flow Cytometry; D005768:Gastrointestinal Hormones / Q000235:genetics / Q000378:metabolism; D054439:Ghrelin / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice
chemical_list: D005768:Gastrointestinal Hormones; D054439:Ghrelin; D002766:Cholecystokinin