title: GLP-1 inhibits VEGFA-mediated signaling in isolated human endothelial cells and VEGFA-induced dilation of rat mesenteric arteries.
abstract: We investigated the acute effects of glucagon-like peptide-1 (GLP-1), GLP-1(1-36), and GLP-1(7-36) on vascular endothelial growth factor-A (VEGFA)-induced endothelium-dependent signaling and vasodilation. Our hypothesis was that GLP-1 released from intestinal l-cells modulates processes related to PLCγ activation, Src, and endothelial NOS (eNOS) signaling, thereby controlling endothelial vessel tone. By using RT-PCR analysis, we found mRNA for the GLP-1 receptor (GLP-1R) in human dermal microvascular endothelial cells (HDMEC), human retinal microvascular endothelial cells, and rat arteries. In isolated rat mesenteric resistance arteries precontracted with the thromboxane analog U46619 to 80-90% of maximum contraction, VEGFA (25 ng/ml) caused a small and gradual relaxation (28.9 ± 3.9%). Pretreatment of arteries with either GLP-1(1-36) (500 nM) or GLP-1(7-36) (1 nM) abolished the VEGFA-induced relaxation. VEGFA-induced relaxations were also inhibited in endothelial-denuded arteries and in arteries pretreated with the nitric oxide synthase (NOS) inhibitor, Nω-nitro-l-arginine methyl ester (100 μM). In vivo studies on male Wistar rats also revealed that GLP-1(7-36) inhibited VEGFA-induced vasodilation of the same arteries. In isolated endothelial cells, GLP-1(1-36) and GLP-1(7-36) caused a reduction in VEGFA-induced phosphorylation of PLCγ. Ca2+imaging of endothelial cells and rat mesenteric resistance arteries using fura-2, revealed that both GLP-1 analogs caused a reduction in VEGFA-induced Ca2+signaling. GLP-1(1-36) also reduced VEGFA-induced eNOS phosphorylation in HDMEC. In conclusion, GLP-1 reduced relaxation induced by VEGFA in resistance arteries by inhibiting VEGFR2-mediated Ca2+signaling and endothelial NO synthesis. GLP-1, on its own, also induced phosphorylation of Src and ERK1/2 that can lead to proliferation and is implicated in vessel permeability.
authors.affiliation: Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Cecilie
authors.initials: C
authors.lastname: Egholm
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Makhala Michell
authors.initials: MM
authors.lastname: Khammy
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dalsgaard
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark; and.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Mazur
authors.affiliation: Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Katerina
authors.initials: K
authors.lastname: Tritsaris
authors.affiliation: Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anker J
authors.initials: AJ
authors.lastname: Hansen
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.|Department of Biomedicine, Aarhus University, Aarhus, Denmark; and.
authors.forename: Christian
authors.initials: C
authors.lastname: Aalkjaer
authors.affiliation: Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark; sdissing@sund.ku.dk.
authors.forename: Steen
authors.identifier: 0000-0002-0741-907X
authors.initials: S
authors.lastname: Dissing
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D020405:Dermis / Q000098:blood supply; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D052216:Glucagon-Like Peptide 1 / Q000031:analogs & derivatives / Q000494:pharmacology*; D000067757:Glucagon-Like Peptide-1 Receptor / Q000235:genetics*; D006801:Humans; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000187:drug effects / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000187:drug effects / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III / Q000187:drug effects / Q000378:metabolism; D051966:Phospholipase C gamma / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D012171:Retinal Vessels / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000187:drug effects / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D004791:Enzyme Inhibitors; D000067757:Glucagon-Like Peptide-1 Receptor; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D052216:Glucagon-Like Peptide 1; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D040301:Vascular Endothelial Growth Factor Receptor-2; D016392:Proto-Oncogene Proteins pp60(c-src); D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D051966:Phospholipase C gamma; D002118:Calcium; D019331:NG-Nitroarginine Methyl Ester
keywords: GLP-1R; PLCγ and eNOS; VEGFA signaling; endothelial cells; vasodilation