Identification and characterization of GLP-1 receptor-expressing cells using a new transgenic mouse model

Diabetes. 2014 Apr;63(4):1224-33. doi: 10.2337/db13-1440. Epub 2013 Dec 2.

Abstract

GLP-1 is an intestinal hormone with widespread actions on metabolism. Therapies based on GLP-1 are highly effective because they increase glucose-dependent insulin secretion in people with type 2 diabetes, but many reports suggest that GLP-1 has additional beneficial or, in some cases, potentially dangerous actions on other tissues, including the heart, vasculature, exocrine pancreas, liver, and central nervous system. Identifying which tissues express the GLP-1 receptor (GLP1R) is critical for the development of GLP-1-based therapies. Our objective was to use a method independent of GLP1R antibodies to identify and characterize the targets of GLP-1 in mice. Using newly generated glp1r-Cre mice crossed with fluorescent reporter strains, we show that major sites of glp1r expression include pancreatic β- and δ-cells, vascular smooth muscle, cardiac atrium, gastric antrum/pylorus, enteric neurones, and vagal and dorsal root ganglia. In the central nervous system, glp1r-fluorescent cells were abundant in the area postrema, arcuate nucleus, paraventricular nucleus, and ventromedial hypothalamus. Sporadic glp1r-fluorescent cells were found in pancreatic ducts. No glp1r-fluorescence was observed in ventricular cardiomyocytes. Enteric and vagal neurons positive for glp1r were activated by GLP-1 and may contribute to intestinal and central responses to locally released GLP-1, such as regulation of intestinal secretomotor activity and appetite.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Central Nervous System / cytology
  • Central Nervous System / metabolism
  • Glucagon-Like Peptide-1 Receptor
  • Heart Atria / cytology
  • Heart Atria / metabolism
  • Islets of Langerhans / cytology
  • Islets of Langerhans / metabolism
  • Mice
  • Mice, Transgenic
  • Muscle, Smooth, Vascular / cytology
  • Muscle, Smooth, Vascular / metabolism
  • Receptors, Glucagon / biosynthesis*

Substances

  • Glp1r protein, mouse
  • Glucagon-Like Peptide-1 Receptor
  • Receptors, Glucagon