Distinct Identity of GLP-1R, GLP-2R, and GIPR Expressing Cells and Signaling Circuits Within the Gastrointestinal Tract

Nadya M Morrow; Antonio A Hanson; Erin E Mulvihill

doi:10.3389/fcell.2021.703966

Distinct Identity of GLP-1R, GLP-2R, and GIPR Expressing Cells and Signaling Circuits Within the Gastrointestinal Tract

Front Cell Dev Biol. 2021 Sep 29:9:703966. doi: 10.3389/fcell.2021.703966. eCollection 2021.

Authors

Nadya M Morrow^{1

2}, Antonio A Hanson^{1

2}, Erin E Mulvihill^{1

2

3

4}

Affiliations

¹ Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, ON, Canada.
² Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.
³ Montreal Diabetes Research Center CRCHUM-Pavillion R, Montreal, QC, Canada.
⁴ Centre for Infection, Immunity and Inflammation, University of Ottawa, Ottawa, ON, Canada.

Abstract

Enteroendocrine cells directly integrate signals of nutrient content within the gut lumen with distant hormonal responses and nutrient disposal via the production and secretion of peptides, including glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP-1) and glucagon-like peptide 2 (GLP-2). Given their direct and indirect control of post-prandial nutrient uptake and demonstrated translational relevance for the treatment of type 2 diabetes, malabsorption and cardiometabolic disease, there is significant interest in the locally engaged circuits mediating these metabolic effects. Although several specific populations of cells in the intestine have been identified to express endocrine receptors, including intraepithelial lymphocytes (IELs) and αβ and γδ T-cells (Glp1r+) and smooth muscle cells (Glp2r+), the definitive cellular localization and co-expression, particularly in regards to the Gipr remain elusive. Here we review the current state of the literature and evaluate the identity of Glp1r, Glp2r, and Gipr expressing cells within preclinical and clinical models. Further elaboration of our understanding of the initiating G-protein coupled receptor (GPCR) circuits engaged locally within the intestine and how they become altered with high-fat diet feeding can offer insight into the dysregulation observed in obesity and diabetes.

Keywords: glucagon-like peptides; glucose-dependent insulinotropic polypeptide; incretins; intestine; metabolism.

Publication types

Review