Egerod, Kristoffer Lihme2; Engelstoft, Maja Storm2; Grunddal, Kaare Villum3; Nøhr, Mark Klitgaard3; Secher, Anna Elisabet Lilja4; Sakata, Ichiro5; Pedersen, Jens6; Windeløv, Johanne A7; Füchtbauer, Ernst-Martin13; Olsen, Jørgen7; Sundler, Frank9; Christensen, Jan P7; Wierup, Nils9; Olsen, Jesper V7; Holst, Jens Juul10; Zigman, Jeffrey M11; Poulsen, Steen S7; Schwartz, Thue W.12
1 Department of Molecular Biology and Genetics, Science and Technology, Aarhus University2 Pharmacology3 Metabolic Receptology4 2012 Institut for Farmakologi og Farmakoterapi5 Department of Internal Medicine, University of Texas Southwestern Medical Center6 Faculty of Health Sciences, University of Copenhagen7 unknown8 Department of Molecular Biology and Genetics - Molecular Cell and Developmental Biology, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University9 Lund University Diabetes Center10 Afd. for Endokrinologisk Forskning11 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas12 Institut for Neurovidenskab og Farmakologi13 Department of Molecular Biology and Genetics - Molecular Cell and Developmental Biology, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University
Enteroendocrine cells such as duodenal cholecystokinin (CCK cells) are generally thought to be confined to certain segments of the gastrointestinal (GI) tract and to store and release peptides derived from only a single peptide precursor. In the current study, however, transgenic mice expressing enhanced green fluorescent protein (eGFP) under the control of the CCK promoter demonstrated a distribution pattern of CCK-eGFP positive cells that extended throughout the intestine. Quantitative PCR and liquid chromatography-mass spectrometry proteomic analyses of isolated, FACS-purified CCK-eGFP-positive cells demonstrated expression of not only CCK but also glucagon-like peptide 1 (GLP-1), gastric inhibitory peptide (GIP), peptide YY (PYY), neurotensin, and secretin, but not somatostatin. Immunohistochemistry confirmed this expression pattern. The broad coexpression phenomenon was observed both in crypts and villi as demonstrated by immunohistochemistry and FACS analysis of separated cell populations. Single-cell quantitative PCR indicated that approximately half of the duodenal CCK-eGFP cells express one peptide precursor in addition to CCK, whereas an additional smaller fraction expresses two peptide precursors in addition to CCK. The coexpression pattern was further confirmed through a cell ablation study based on expression of the human diphtheria toxin receptor under the control of the proglucagon promoter, in which activation of the receptor resulted in a marked reduction not only in GLP-1 cells, but also PYY, neurotensin, GIP, CCK, and secretin cells, whereas somatostatin cells were spared. Key elements of the coexpression pattern were confirmed by immunohistochemical double staining in human small intestine. It is concluded that a lineage of mature enteroendocrine cells have the ability to coexpress members of a group of functionally related peptides: CCK, secretin, GIP, GLP-1, PYY, and neurotensin, suggesting a potential therapeutic target for the treatment and prevention of diabetes and obesity.
Contemporary Endocrinology, 2012, Vol 153, Issue 12, p. 5782-5795