title: Microfibril-associate glycoprotein-2 (MAGP-2) promotes angiogenic cell sprouting by blocking notch signaling in endothelial cells.
abstract: Angiogenesis is highly sensitive to the composition of the vascular microenvironment, however, our understanding of the structural and matricellular components of the vascular microenvironment that regulate angiogenesis and the molecular mechanisms by which these molecules function remains incomplete. Our previous results described a novel pro-angiogenic activity for Microfibril-Associated Glycoprotein-2 (MAGP-2), but did not address the molecular mechanism(s) by which this is accomplished. We now demonstrate that MAGP-2 promotes angiogenic cell sprouting by antagonizing Notch signaling pathways in endothelial cells. MAGP-2 decreased basal and Jagged1 induced expression from the Notch sensitive Hes-1 promoter in ECs, and blocked Jagged1 stimulated Notch1 receptor processing in transiently transfected 293T cells. Interestingly, inhibition of Notch signaling by MAGP-2 seems to be restricted to ECs since MAGP-2 increased Hes-1 promoter activity and Notch1 receptor processing in heterologous cell types. Importantly, constitutive activation of the Notch signaling pathway blocked the ability of MAGP-2 to promote angiogenic cell sprouting, as well as morphological changes associated with angiogenesis. Collectively, these observations indicate that MAGP-2 promotes angiogenic cell spouting in vitro by antagonizing Notch signaling pathways in ECs.
authors.affiliation: Department of Life Sciences, 600 Chestnut St., Indiana State University, Terre Haute, IN 47809, USA. aalbig@isugw.indstate.edu
authors.forename: Allan R
authors.initials: AR
authors.lastname: Albig
authors.forename: Darryl J
authors.initials: DJ
authors.lastname: Becenti
authors.forename: Thessa G
authors.initials: TG
authors.lastname: Roy
authors.forename: William P
authors.initials: WP
authors.lastname: Schiemann
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D003285:Contractile Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D004151:Dipeptides / Q000494:pharmacology; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006023:Glycoproteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007365:Intercellular Junctions / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D000072100:Jagged-1 Protein; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D051881:Receptor, Notch1 / Q000235:genetics / Q000378:metabolism; D051880:Receptors, Notch / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology; D000072099:Serrate-Jagged Proteins; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D000072056:Transcription Factor HES-1; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D051176:beta Catenin / Q000378:metabolism
chemical_list: D000199:Actins; D051792:Basic Helix-Loop-Helix Proteins; D002135:Calcium-Binding Proteins; D003285:Contractile Proteins; D004151:Dipeptides; D004791:Enzyme Inhibitors; D006023:Glycoproteins; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008156:Luciferases; D008565:Membrane Proteins; D051881:Receptor, Notch1; D051880:Receptors, Notch; D011994:Recombinant Proteins; D000072099:Serrate-Jagged Proteins; D000072056:Transcription Factor HES-1; D016212:Transforming Growth Factor beta; D051176:beta Catenin; C495267:CTNNB1 protein, mouse; C000606273:JAG1 protein, human; C000606274:Jag1 protein, mouse; C115627:MFAP5 protein, human; C419410:N-(N-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl ester; C078493:HES1 protein, human