scholarly journals Urokinase-type plasminogen activator is induced in migrating capillary endothelial cells.

1987 ◽  
Vol 105 (6) ◽  
pp. 2535-2541 ◽  
Author(s):  
M S Pepper ◽  
J D Vassalli ◽  
R Montesano ◽  
L Orci
Keyword(s):  
Cell Migration ◽  
Endothelial Cell ◽  
Plasminogen Activator ◽  
Cellular Migration ◽  
Endothelial Cell Migration ◽  
Vascular Lesions ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator

Cellular migration is an essential component of invasive biological processes, many of which have been correlated with an increase in plasminogen activator production. Endothelial cell migration occurs in vivo during repair of vascular lesions and angiogenesis, and can be induced in vitro by wounding a confluent monolayer of cells. By combining the wounded monolayer model with a substrate overlay technique, we show that cells migrating from the edges of an experimental wound display an increase in urokinase-type plasminogen activator (uPA) activity, and that this activity reverts to background levels upon cessation of movement, when the wound has closed. Our results demonstrate a direct temporal relationship between endothelial cell migration and uPA activity, and suggest that induction of uPA activity is a component of the migratory process.

scholarly journals uPAR Directly Interacts with LDLR-like Proteins to Induce Angiogenic Endothelial Cell Behavior

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4172-4172
Author(s):  
Clemens Pausz ◽  
Rula Mawas ◽  
Matthias Unseld ◽  
Anastasia Chilla ◽  
René Novotny ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Endothelial Cell Migration ◽  
Migration And Invasion ◽  
Binding Motif ◽  
Wild Type ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Domain 3

Abstract In this study we characterized a conserved motif of domain 3 of the urokinase-type plasminogen activator receptor (uPAR) to directly interact with low-density lipoprotein receptor (LDLR)-related protein (LRP) family proteins, thereby affecting endothelial cell motility and angiogenesis in vitro and in vivo. There is increasing evidence that uPAR plays a central role in growth factor induced endothelial cell activation. Beside its proteolytic role, urokinase-type plasminogen activator (uPA) / uPAR-complex formation induces intracellular signal transduction, which leads to endothelial cell migration and invasion. Since uPAR is a GPI-anchored protein, an interaction with transmembrane proteins - such as members of the LDL-receptor family - is required, inducing signal transduction but also regulating distribution of uPAR via its internalization and recycling to the leading edge. Recently, a direct interaction between uPAR and LRP-family members has been suggested to be sufficient to mediate internalization of uPAR-complex. A crystal structure analysis revealed a small sequence of domain 3 (D3) of uPAR, to be highly exposed upon uPA binding to its receptor. Applying affinity chromatography analysis as well as mutation expression studies, we identified the sequence as an LRP-binding motif, which affects endothelial cell spreading, migration and invasion upon VEGF in vivo as well as in vitro. In detail, matrigel-filled angioreactors with embedded retroviral constructs, carrying wild-type or modified uPAR genes, were implanted subcutaneously into uPAR deficient C57BL/6 mice. After explantation, blood vessel in-growth analysis revealed that only angioreactors with reconstituted wild-type uPAR but not reactors with modified uPAR, being deficient in LDLR interaction, showed angiogenesis. To test a therapeutic impact, peptides mimicking the binding motif and competitive for LDLR binding were used. We found that in a dose dependent manner the peptides did not only block uPAR/LDLR-like protein interaction, but were also capable of blocking VEGF-induced endothelial cell migration in vitro. In summary, our data show that a conserved motif of uPAR domain 3 is capable to interact with LDLR-like proteins, which is required for efficient growth-factor induced endothelial cell behavior. Preliminary functional data suggest that this extracellular motif might be a potential therapeutic target in angiogenesis dependent diseases such as cancer. Disclosures No relevant conflicts of interest to declare.

Vascular endothelial growth factor (VEGF) in cartilage neovascularization and chondrocyte differentiation: auto-paracrine role during endochondral bone formation

2000 ◽  
Vol 113 (1) ◽  
pp. 59-69 ◽  
Author(s):  
M.F. Carlevaro ◽  
S. Cermelli ◽  
R. Cancedda ◽  
F. Descalzi Cancedda
Keyword(s):  
Endothelial Cells ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Hypertrophic Chondrocytes ◽  
Endothelial Cell Migration ◽  
Vegf Receptor ◽  
Hypertrophic Cartilage ◽  
Endothelial Growth Factor

Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) induces endothelial cell migration and proliferation in culture and is strongly angiogenic in vivo. VEGF synthesis has been shown to occur in both normal and transformed cells. The receptors for the factor have been shown to be localized mainly in endothelial cells, however, the presence of VEGF synthesis and the VEGF receptor in cells other than endothelial cells has been demonstrated. Neoangiogenesis in cartilage growth plate plays a fundamental role in endochondral ossification. We have shown that, in an avian in vitro system for chondrocyte differentiation, VEGF was produced and localized in cell clusters totally resembling in vivo cartilage. The factor was synthesized by hypertrophic chondrocytes and was released into their conditioned medium, which is highly chemotactic for endothelial cells. Antibodies against VEGF inhibited endothelial cell migration induced by chondrocyte conditioned media. Similarly, endothelial cell migration was inhibited also by antibodies directed against the VEGF receptor 2/Flk1 (VEGFR2). In avian and mammalian embryo long bones, immediately before vascular invasion, VEGF was distinctly localized in growth plate hypertrophic chondrocytes. In contrast, VEGF was not observed in quiescent and proliferating chondrocytes earlier in development. VEGF receptor 2 colocalized with the factor both in hypertrophic cartilage in vivo and hypertrophic cartilage engineered in vitro, suggesting an autocrine loop in chondrocytes at the time of their maturation to hypertrophic cells and of cartilage erosion. Regardless of cell exposure to exogenous VEGF, VEGFR-2 phosphorylation was recognized in cultured hypertrophic chondrocytes, supporting the idea of an autocrine functional activation of signal transduction in this non-endothelial cell type as a consequence of the endogenous VEGF production. In summary we propose that VEGF is actively responsible for hypertrophic cartilage neovascularization through a paracrine release by chondrocytes, with invading endothelial cells as a target. Furthermore, VEGF receptor localization and signal transduction in chondrocytes strongly support the hypothesis of a VEGF autocrine activity also in morphogenesis and differentiation of a mesoderm derived cell.

ON THE MECHANISM OF THE IN VIVO SYNERGISM BETWEEN TISSUE-TYPE PLASMINOGEN ACTIVATOR (t-PA) AND SINGLE CHAIN UROKINASE-TYPE PLASMINOGEN ACTIVATOR (scu-PA)

1987 ◽  
Author(s):  
J M Stassen ◽  
D Collen
Keyword(s):  
Plasminogen Activator ◽  
Rabbit Model ◽  
Sequential Therapy ◽  
Tissue Type ◽  
Single Chain ◽  
Molar Ratios ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator

t-PA and scu-PA, in molar ratios between 1:4 and 4:1 do not act synergically in vitro (Thromb. Haemost. 56,35,1986) but display marked synergism in a rabbit model (Circulation 74, 838, 1986) and in man (Am. Heart J. 112, 1083, 1986). To investigate the mechanism of in vivo synergism in the rabbit model (J. Clin. Invest. 71, 368, 1983), t-PA and scu-PA were infused 1) simultaneously over 4 hrs, 2) t-PA over 1 hr, then 15 min later scu-PA over 2 hrs and 3) scu-PA over 1 hr, then 15 min later t-PA over 2 hrs.Significant synergism on thrombolysis is observed when t-PA and scu-PA are infused simultaneously or when t-PA is followed by scu-PA but not when scu-PA is followed by t-PA. These results suggest that low dose t-PA induces some plasminogen activation, sufficient to partially degrade fibrin, exposing COOH-terminal lysines with high affinity for plasminogen (Eur. J. Biochem. 140, 513, 1984). scu-PA might then activate surface-bound Glu-pla-minogen more efficiently.Sequential therapy with t-PA (or any other agent which "predigests" the thrombus), followed by scu-PA might constitute an alternative to simultaneous infusion of synergistic thrombolytic agents.

CYLD regulates angiogenesis by mediating vascular endothelial cell migration

Blood ◽  
2010 ◽  
Vol 115 (20) ◽  
pp. 4130-4137 ◽  
Author(s):  
Jinmin Gao ◽  
Lei Sun ◽  
Lihong Huo ◽  
Min Liu ◽  
Dengwen Li ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Vascular Endothelial Cells ◽  
Vascular Endothelial Cell ◽  
Tube Formation ◽  
Endothelial Cell Migration ◽  
Vascular Endothelial

Cylindromatosis (CYLD) is a deubiquitinase that was initially identified as a tumor suppressor and has recently been implicated in diverse normal physiologic processes. In this study, we have investigated the involvement of CYLD in angiogenesis, the formation of new blood vessels from preexisting ones. We find that knockdown of CYLD expression significantly impairs angiogenesis in vitro in both matrigel-based tube formation assay and collagen-based 3-dimensional capillary sprouting assay. Disruption of CYLD also remarkably inhibits angiogenic response in vivo, as evidenced by diminished blood vessel growth into the angioreactors implanted in mice. Mechanistic studies show that CYLD regulates angiogenesis by mediating the spreading and migration of vascular endothelial cells. Silencing of CYLD dramatically decreases microtubule dynamics in endothelial cells and inhibits endothelial cell migration by blocking the polarization process. Furthermore, we identify Rac1 activation as an important factor contributing to the action of CYLD in regulating endothelial cell migration and angiogenesis. Our findings thus uncover a previously unrecognized role for CYLD in the angiogenic process and provide a novel mechanism for Rac1 activation during endothelial cell migration and angiogenesis.

scholarly journals Mast Cell Protease 7 Promotes Angiogenesis by Degradation of Integrin Subunits

Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 349
Author(s):  
Devandir A. de Souza Junior ◽  
Carolina Santana ◽  
Gabriel V. Vieira ◽  
Constance Oliver ◽  
Maria Celia Jamur
Keyword(s):  
Endothelial Cells ◽  
Mast Cell ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Direct Action ◽  
Endothelial Cell Migration ◽  
Loop Formation ◽  
Mast Cell Protease

Previous studies from our laboratory have shown that during angiogenesis in vitro, rmMCP-7 (recombinant mouse mast cell protease-7) stimulates endothelial cell spreading and induces their penetration into the matrix. The ability of rmMCP-7 to induce angiogenesis in vivo was assessed in the present study using a directed in vivo angiogenesis assay (DIVAA™). Vessel invasion of the angioreactor was observed in the presence of rmMCP-7 but was not seen in the control. Since integrins are involved in endothelial cell migration, the relationship between rmMCP-7 and integrins during angiogenesis was investigated. Incubation with rmMCP-7 resulted in a reduction in the levels of integrin subunits αv and β1 on SVEC4-10 endothelial cells during angiogenesis in vitro. Furthermore, the degradation of integrin subunits occurs both through the direct action of rmMCP-7 and indirectly via the ubiquitin/proteasome system. Even in the presence of a proteasome inhibitor, incubation of endothelial cells with rmMCP-7 induced cell migration and tube formation as well as the beginning of loop formation. These data indicate that the direct degradation of the integrin subunits by rmMCP-7 is sufficient to initiate angiogenesis. The results demonstrate, for the first time, that mMCP-7 acts in angiogenesis through integrin degradation.

Participation of urokinase-type plasminogen activator receptor in the clearance of fibrin from the lung

1999 ◽  
Vol 277 (3) ◽  
pp. L573-L579 ◽  
Author(s):  
Noboru Hattori ◽  
Thomas H. Sisson ◽  
Yin Xu ◽  
Tushar J. Desai ◽  
Richard H. Simon
Keyword(s):  
Plasminogen Activator ◽  
Cell Surface Receptor ◽  
Biologically Relevant ◽  
Knowing That ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Surface Receptor ◽  
Species Specific

In vitro studies have demonstrated that the binding of urokinase-type plasminogen activator (uPA) to its cell surface receptor (uPAR) greatly accelerates plasminogen activation. However, the role of uPAR in clearing abnormal fibrin deposits from the lung is uncertain. Knowing that uPA binding to uPAR is species specific, we used adenoviral vectors to transfer human or murine uPA genes into human or mouse epithelial cells in vitro and to mouse lungs in vivo. By measuring degradation of fluorescein-labeled fibrin, we found that uPA lysed fibrin matrices more efficiently when expressed in cells of the same species. A monoclonal antibody that blocks the binding of human uPA to human uPAR suppressed fibrin degradation by human cells expressing human uPA but not murine uPA. Importantly, 3 days after intratracheal delivery of the vectors, mice receiving murine uPA transgenes degraded fibrin matrices formed within their air spaces more efficiently than animals transduced with human uPA genes. These results show that uPA bound to uPAR increases the efficiency of fibrinolysis on epithelial cell surfaces in a biologically relevant fashion.

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