title: Involvement of vascular endothelial growth factor signaling in CLR/RAMP1 and CLR/RAMP2-mediated pro-angiogenic effect of intermedin on human vascular endothelial cells.
abstract: Intermedin (IMD) is a recently discovered peptide closely related to adrenomedullin. Its principal physiological activity is its role in the regulation of the cardiovascular system, where it exerts a potent hypotensive effect. In addition, data were recently provided showing that this peptide is able to exert a clearcut pro-angiogenic effect both in vitro and in vivo. IMD acts through the non-selective interaction with receptor complexes formed by the dimerization of calcitonin-like receptor (CLR) with the receptor activity-modifying proteins RAMP1, 2 or 3. Thus, in the present study, the role of CLR/RAMP complexes in mediating the pro-angiogenic effect induced by IMD on human umbilical vein endothelial cells (HUVECs) cultured on Matrigel was examined. Real-time PCR demonstrated the expression of IMD, CLR/RAMP1 and CLR/RAMP2 (but not CLR/RAMP3) mRNA in HUVECs. IMD exerted a significant in vitro angiogenic action, specifically triggered by the binding of the peptide to CLR/RAMP complexes. Both CLR/RAMP1 and CLR/RAMP2 appeared to mediate the pro-angiogenic effect, which was associated with a significant increase of vascular endothelial growth factor (VEGF) mRNA expression 18 h following IMD administration, indicating that the observed pro-angiogenic effects are related, at least in part, to an increased synthesis of this growth factor promoted by the peptide. Western blot analysis, however, showed a significant increase of VEGF receptor-2 phosphorylation as early as 5 min following IMD administration, indicating that IMD induces a pro-angiogenic response in human vascular endothelial cells not only via CLR/RAMP-induced release of VEGF, but also during signal initiation and propagation by transactivating the VEGF receptor-2 machinery.
authors.affiliation: Department of Human Anatomy and Physiology, Section of Anatomy, University of Padova-Medical School, I-35121 Padova, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Albertin
authors.forename: Elisa
authors.initials: E
authors.lastname: Sorato
authors.forename: Barbara
authors.initials: B
authors.lastname: Oselladore
authors.forename: Alessandra
authors.initials: A
authors.lastname: Mascarin
authors.forename: Cinzia
authors.initials: C
authors.lastname: Tortorella
authors.forename: Diego
authors.initials: D
authors.lastname: Guidolin
mesh_terms: D000704:Analysis of Variance; D015415:Biomarkers / Q000378:metabolism; D058286:Calcitonin Receptor-Like Protein; D002478:Cells, Cultured; D003094:Collagen; D004338:Drug Combinations; D042783:Endothelial Cells / Q000378:metabolism*; D020868:Gene Silencing; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D007797:Laminin; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018919:Neovascularization, Physiologic; D036361:Peptide Hormones / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011509:Proteoglycans; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D058262:Receptor Activity-Modifying Protein 1; D058263:Receptor Activity-Modifying Protein 2; D058264:Receptor Activity-Modifying Protein 3; D058261:Receptor Activity-Modifying Proteins; D018003:Receptors, Calcitonin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: C484330:ADM2 protein, human; D015415:Biomarkers; C545578:CALCRL protein, human; D058286:Calcitonin Receptor-Like Protein; D004338:Drug Combinations; D047908:Intracellular Signaling Peptides and Proteins; D007797:Laminin; D008565:Membrane Proteins; D036361:Peptide Hormones; D011509:Proteoglycans; C545502:RAMP1 protein, human; C545503:RAMP2 protein, human; C545504:RAMP3 protein, human; D012333:RNA, Messenger; D058262:Receptor Activity-Modifying Protein 1; D058263:Receptor Activity-Modifying Protein 2; D058264:Receptor Activity-Modifying Protein 3; D058261:Receptor Activity-Modifying Proteins; D018003:Receptors, Calcitonin; D042461:Vascular Endothelial Growth Factor A; C059485:matrigel; D003094:Collagen; D040301:Vascular Endothelial Growth Factor Receptor-2