title: VEGF-A stimulates podosome-mediated collagen-IV proteolysis in microvascular endothelial cells.
abstract: Podosomes are dynamic cell-matrix contact structures that combine several key abilities, including adhesion, matrix degradation and mechanosensing. These actin-based cytoskeletal structures have been mostly studied in monocytic cells, but much less is known about those formed in other lineages. In this study, we characterise podosomes in capillary-derived microvascular endothelial cells. We identify two types of podosomes: constitutive podosomes that form in the absence of specific stimulation and induced podosomes that arise in response to the angiogenic factor VEGF-A. Constitutive and VEGF-A-induced podosomes share similar components but exhibit marked differences in terms of gelatinolytic activity. We also show that the extracellular matrix proteins laminin and collagen-IV are key determinants of the VEGF-A response, but neither collagen-I nor fibronectin are conducive for podosome induction. Moreover, only collagen-IV elicits the formation of proteolytically active podosomes through a mechanism involving increased Src phosphorylation, p190RhoGAP-B (also known as ARHGAP5) relocalisation and MT1-MMP (also known as MMP14) cell surface exposure at podosome sites. We hypothesise that by promoting podosome formation, VEGF-A enables endothelial cells to overcome the basement membrane barrier to allow sprouting outwards from the existing vasculature.
authors.affiliation: Université de Bordeaux, 33 000 Bordeaux, France.
authors.forename: Thomas
authors.identifier: 0000-0003-0622-7946
authors.initials: T
authors.lastname: Daubon
authors.affiliation: Université de Bordeaux, 33 000 Bordeaux, France INSERM U1045, 33 000 Bordeaux, France.
authors.forename: Pirjo
authors.identifier: 0000-0001-9410-721X
authors.initials: P
authors.lastname: Spuul
authors.affiliation: Université de Bordeaux, 33 000 Bordeaux, France INSERM U1045, 33 000 Bordeaux, France.
authors.forename: Florian
authors.identifier: 0000-0002-6794-1513
authors.initials: F
authors.lastname: Alonso
authors.affiliation: Université de Bordeaux, 33 000 Bordeaux, France INSERM U1045, 33 000 Bordeaux, France.
authors.forename: Isabelle
authors.identifier: 0000-0002-3632-6016
authors.initials: I
authors.lastname: Fremaux
authors.affiliation: Université de Bordeaux, 33 000 Bordeaux, France INSERM U1045, 33 000 Bordeaux, France elisabeth.genot@inserm.fr.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Génot
mesh_terms: D000199:Actins / Q000235:genetics; D024141:Collagen Type IV / Q000096:biosynthesis / Q000235:genetics*; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000096:biosynthesis / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D053511:Matrix Metalloproteinase 14 / Q000096:biosynthesis / Q000235:genetics*; D010766:Phosphorylation; D000069261:Podosomes / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis; D042461:Vascular Endothelial Growth Factor A / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: C513043:ARHGAP5 protein, human; D000199:Actins; D024141:Collagen Type IV; D020690:GTPase-Activating Proteins; D042461:Vascular Endothelial Growth Factor A; C507086:MMP14 protein, human; D053511:Matrix Metalloproteinase 14
keywords: Basement membrane; Collagen-IV; Endothelial cells; Podosomes; VEGF-A