GLP-2 receptor localizes to enteric neurons and endocrine cells expressing vasoactive peptides and mediates increased blood flow

TY - JOUR

T1 - GLP-2 receptor localizes to enteric neurons and endocrine cells expressing vasoactive peptides and mediates increased blood flow

AU - Guan, Xinfu

AU - Karpen, Heidi E

AU - Stephens, John

AU - Bukowski, John T

AU - Niu, Sanyong

AU - Zhang, Guangcheng

AU - Stoll, Barbara

AU - Finegold, Milton J

AU - Holst, Jens Juul

AU - Hadsell, Darryl

AU - Hadsell, Darry L

AU - Nichols, Buford L

AU - Burrin, Douglas G

PY - 2006/1

Y1 - 2006/1

N2 - BACKGROUND & AIMS: Glucagon-like peptide-2 (GLP-2) is a nutrient-responsive hormone that exerts diverse actions in the gastrointestinal tract, including enhancing epithelial cell survival and proliferation, mucosal blood flow, and nutrient uptake and suppressing gastric motility and secretion. These actions are mediated by the G-protein-coupled receptor, GLP-2R. Cellular localization of the GLP-2R and the nature of its signaling network in the gut, however, are poorly defined. Thus, our aim was to establish cellular localization of GLP-2R and functional connection to vascular action of GLP-2 in the gut.METHODS: Intestinal cellular GLP-2R localization was determined with real-time, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) of laser capture microdissected subtissue and fluorescence in situ hybridization and also with double and/or triple immunostaining of human and pig tissue using a validated GLP-2R polyclonal antibody. Superior mesenteric arterial blood flow and intestinal eNOS expression and phosphorylation were measured in TPN-fed pigs acutely (4 h) infused with GLP-2.RESULTS: We show that the porcine GLP-2R mRNA was expressed in the villus epithelium and myenteric plexus. GLP-2R protein was co-localized by confocal immunohistochemistry with serotonin in enteroendocrine cells and also with endothelial nitric oxide synthase (eNOS)-expressing and vasoactive intestinal polypeptide-positive enteric neurons. In neonatal pigs, GLP-2 infusion dose-dependently stimulated intestinal blood flow and coordinately upregulated the expression of intestinal eNOS mRNA, protein, and phosphorylation (eNOS-Ser1117).CONCLUSIONS: We conclude that the GLP-2-induced stimulation of blood flow is mediated by vasoactive neurotransmitters that are colocalized with GLP-2R in 2 functionally distinct cell types within the gastrointestinal tract.

AB - BACKGROUND & AIMS: Glucagon-like peptide-2 (GLP-2) is a nutrient-responsive hormone that exerts diverse actions in the gastrointestinal tract, including enhancing epithelial cell survival and proliferation, mucosal blood flow, and nutrient uptake and suppressing gastric motility and secretion. These actions are mediated by the G-protein-coupled receptor, GLP-2R. Cellular localization of the GLP-2R and the nature of its signaling network in the gut, however, are poorly defined. Thus, our aim was to establish cellular localization of GLP-2R and functional connection to vascular action of GLP-2 in the gut.METHODS: Intestinal cellular GLP-2R localization was determined with real-time, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) of laser capture microdissected subtissue and fluorescence in situ hybridization and also with double and/or triple immunostaining of human and pig tissue using a validated GLP-2R polyclonal antibody. Superior mesenteric arterial blood flow and intestinal eNOS expression and phosphorylation were measured in TPN-fed pigs acutely (4 h) infused with GLP-2.RESULTS: We show that the porcine GLP-2R mRNA was expressed in the villus epithelium and myenteric plexus. GLP-2R protein was co-localized by confocal immunohistochemistry with serotonin in enteroendocrine cells and also with endothelial nitric oxide synthase (eNOS)-expressing and vasoactive intestinal polypeptide-positive enteric neurons. In neonatal pigs, GLP-2 infusion dose-dependently stimulated intestinal blood flow and coordinately upregulated the expression of intestinal eNOS mRNA, protein, and phosphorylation (eNOS-Ser1117).CONCLUSIONS: We conclude that the GLP-2-induced stimulation of blood flow is mediated by vasoactive neurotransmitters that are colocalized with GLP-2R in 2 functionally distinct cell types within the gastrointestinal tract.

KW - Animals

KW - Enteroendocrine Cells

KW - Female

KW - Humans

KW - Immunohistochemistry

KW - In Situ Hybridization, Fluorescence

KW - Intestine, Small

KW - Mesenteric Arteries

KW - Neurons

KW - Nitric Oxide Synthase Type III

KW - RNA, Messenger

KW - Receptors, Glucagon

KW - Regional Blood Flow

KW - Reverse Transcriptase Polymerase Chain Reaction

KW - Swine

KW - Vasoactive Intestinal Peptide

U2 - 10.1053/j.gastro.2005.11.005

DO - 10.1053/j.gastro.2005.11.005

M3 - Journal article

C2 - 16401478

SN - 0016-5085

VL - 130

SP - 150

EP - 164

JO - Gastroenterology

JF - Gastroenterology

IS - 1

ER -