A major lineage of enteroendocrine cells coexpress CCK, secretin, GIP, GLP-1, PYY, and neurotensin but not somatostatin.
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.
Novo Nordisk Foundation Center for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, Faculty of Health Sciences, University of Copenhagen, 2200 Denmark.
Kristoffer L
KL
Egerod
Maja S
MS
Engelstoft
Kaare V
KV
Grunddal
Mark K
MK
Nøhr
Anna
A
Secher
Ichiro
I
Sakata
Jens
J
Pedersen
Johanne A
JA
Windeløv
Ernst-Martin
EM
Füchtbauer
Jørgen
J
Olsen
Frank
F
Sundler
Jan P
JP
Christensen
Nils
N
Wierup
Jesper V
JV
Olsen
Jens J
JJ
Holst
Jeffrey M
JM
Zigman
Steen S
SS
Poulsen
Thue W
TW
Schwartz
D000818:Animals; D019070:Cell Lineage; D002469:Cell Separation; D002766:Cholecystokinin / Q000096:biosynthesis*; D003920:Diabetes Mellitus / Q000517:prevention & control; D019858:Enteroendocrine Cells / Q000166:cytology* / Q000378:metabolism; D005434:Flow Cytometry; D005749:Gastric Inhibitory Polypeptide / Q000096:biosynthesis*; D005786:Gene Expression Regulation; D054439:Ghrelin / Q000378:metabolism; D052216:Glucagon-Like Peptide 1 / Q000096:biosynthesis*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007413:Intestinal Mucosa / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009496:Neurotensin / Q000096:biosynthesis*; D009765:Obesity / Q000517:prevention & control; D019894:Peptide YY / Q000378:metabolism*; D011401:Promoter Regions, Genetic
D054439:Ghrelin; D019894:Peptide YY; D049452:Green Fluorescent Proteins; D009496:Neurotensin; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1; D002766:Cholecystokinin