VE-PTP maintains the endothelial barrier via plakoglobin and becomes dissociated from VE-cadherin by leukocytes and by VEGF

We have shown recently that vascular endothelial protein tyrosine phosphatase (VE-PTP), an endothelial-specific membrane protein, associates with vascular endothelial (VE)–cadherin and enhances VE-cadherin function in transfected cells (Nawroth, R., G. Poell, A. Ranft, U. Samulowitz, G. Fachinger, M. Golding, D.T. Shima, U. Deutsch, and D. Vestweber. 2002. EMBO J. 21:4885–4895). We show that VE-PTP is indeed required for endothelial cell contact integrity, because down-regulation of its expression enhanced endothelial cell permeability, augmented leukocyte transmigration, and inhibited VE-cadherin–mediated adhesion. Binding of neutrophils as well as lymphocytes to endothelial cells triggered rapid (5 min) dissociation of VE-PTP from VE-cadherin. This dissociation was only seen with tumor necrosis factor α–activated, but not resting, endothelial cells. Besides leukocytes, vascular endothelial growth factor also rapidly dissociated VE-PTP from VE-cadherin, indicative of a more general role of VE-PTP in the regulation of endothelial cell contacts. Dissociation of VE-PTP and VE-cadherin in endothelial cells was accompanied by tyrosine phoshorylation of VE-cadherin, β-catenin, and plakoglobin. Surprisingly, only plakoglobin but not β-catenin was necessary for VE-PTP to support VE-cadherin adhesion in endothelial cells. In addition, inhibiting the expression of VE-PTP preferentially increased tyrosine phosphorylation of plakoglobin but not β-catenin. In conclusion, leukocytes interacting with endothelial cells rapidly dissociate VE-PTP from VE-cadherin, weakening endothelial cell contacts via a mechanism that requires plakoglobin but not β-catenin.

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Andes Virus Disrupts the Endothelial Cell Barrier by Induction of Vascular Endothelial Growth Factor and Downregulation of VE-Cadherin

Journal of Virology ◽

10.1128/jvi.01405-10 ◽

2010 ◽

Vol 84 (21) ◽

pp. 11227-11234 ◽

Cited By ~ 74

Author(s):

Punya Shrivastava-Ranjan ◽

Pierre E. Rollin ◽

Christina F. Spiropoulou

Keyword(s):

Vascular Endothelial Growth Factor ◽

Endothelial Cells ◽

Endothelial Cell ◽

Growth Factor ◽

Virus Replication ◽

Cell Permeability ◽

Hantavirus Infection ◽

Vascular Endothelial ◽

Andes Virus ◽

Endothelial Growth Factor

ABSTRACT Hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS) are severe diseases associated with hantavirus infection. High levels of virus replication occur in microvascular endothelial cells but without a virus-induced cytopathic effect. However, virus infection results in microvascular leakage, which is the hallmark of these diseases. VE-cadherin is a major component of adherens junctions, and its interaction with the vascular endothelial growth factor (VEGF) receptor, VEGF-R2, is important for maintaining the integrity of the endothelial barrier. Here we report that increased secreted VEGF and concomitant decreased VE-cadherin are seen at early times postinfection of human primary lung endothelial cells with an HPS-associated hantavirus, Andes virus. Furthermore, active virus replication results in increased permeability and loss of the integrity of the endothelial cell barrier. VEGF binding to VEGF-R2 is known to result in dissociation of VEGF-R2 from VE-cadherin and in VE-cadherin activation, internalization, and degradation. Consistent with this, we showed that an antibody which blocks VEGF-R2 activation resulted in inhibition of the Andes virus-induced VE-cadherin reduction. These data implicate virus induction of VEGF and reduction in VE-cadherin in the endothelial cell permeability seen in HPS and suggest potential immunotherapeutic targets for the treatment of the disease.

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Dissociation of VE-PTP from VE-cadherin is required for leukocyte extravasation and for VEGF-induced vascular permeability in vivo

Journal of Experimental Medicine ◽

10.1084/jem.20110525 ◽

2011 ◽

Vol 208 (12) ◽

pp. 2393-2401 ◽

Cited By ~ 122

Author(s):

Andre Broermann ◽

Mark Winderlich ◽

Helena Block ◽

Maike Frye ◽

Jan Rossaint ◽

...

Keyword(s):

Endothelial Cell ◽

Vascular Permeability ◽

Fusion Proteins ◽

Tyrosine Phosphatase ◽

Cell Contact ◽

Vascular Endothelial ◽

Cell Contacts ◽

Leukocyte Extravasation

We have recently shown that vascular endothelial protein tyrosine phosphatase (VE-PTP), an endothelial membrane protein, associates with VE-cadherin and is required for optimal VE-cadherin function and endothelial cell contact integrity. The dissociation of VE-PTP from VE-cadherin is triggered by vascular endothelial growth factor (VEGF) and by the binding of leukocytes to endothelial cells in vitro, suggesting that this dissociation is a prerequisite for the destabilization of endothelial cell contacts. Here, we show that VE-cadherin/VE-PTP dissociation also occurs in vivo in response to LPS stimulation of the lung or systemic VEGF stimulation. To show that this dissociation is indeed necessary in vivo for leukocyte extravasation and VEGF-induced vascular permeability, we generated knock-in mice expressing the fusion proteins VE-cadherin-FK 506 binding protein and VE-PTP-FRB* under the control of the endogenous VE-cadherin promoter, thus replacing endogenous VE-cadherin. The additional domains in both fusion proteins allow the heterodimeric complex to be stabilized by a chemical compound (rapalog). We found that intravenous application of the rapalog strongly inhibited VEGF-induced (skin) and LPS-induced (lung) vascular permeability and inhibited neutrophil extravasation in the IL-1β inflamed cremaster and the LPS-inflamed lung. We conclude that the dissociation of VE-PTP from VE-cadherin is indeed required in vivo for the opening of endothelial cell contacts during induction of vascular permeability and leukocyte extravasation.

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Inhibition of vascular endothelial growth factor receptor 2–mediated endothelial cell activation by Axl tyrosine kinase receptor

Blood ◽

10.1182/blood-2004-04-1469 ◽

2005 ◽

Vol 105 (5) ◽

pp. 1970-1976 ◽

Cited By ~ 67

Author(s):

Margherita Gallicchio ◽

Stefania Mitola ◽

Donatella Valdembri ◽

Roberto Fantozzi ◽

Brian Varnum ◽

...

Keyword(s):

Vascular Endothelial Growth Factor ◽

Endothelial Cells ◽

Endothelial Cell ◽

Growth Factor ◽

Tyrosine Kinase ◽

Tyrosine Phosphatase ◽

Tyrosine Kinase Receptor ◽

Vegf Receptor ◽

Vascular Endothelial ◽

Endothelial Growth Factor

AbstractGAS6, the product of a growth arrest specific (GAS) gene, is the ligand of the tyrosine kinase receptor Axl. GAS6 and Axl are both expressed in endothelial cells, where they are involved in many processes such as leukocyte transmigration through capillaries and neointima formation in injured vessels. Here, we show that Axl stimulation by GAS6 results in inhibition of the ligand-dependent activation of vascular endothelial growth factor (VEGF) receptor 2 and the consequent activation of an angiogenic program in vascular endothelial cells. GAS6 inhibits chemotaxis of endothelial cells stimulated by VEGF-A isoforms, but not that triggered by fibroblast growth factor-2 or hepatocyte growth factor. Furthermore, it inhibits endothelial cell morphogenesis on Matrigel and VEGF-A–dependent vascularization of chick chorion allantoid membrane. GAS6 activates the tyrosine phosphatase SHP-2 (SH2 domain-containing tyrosine phosphatase 2), which is instrumental in the negative feedback exerted by Axl on VEGF-A activities. A dominant-negative SHP-2 mutant, in which Cys 459 is substituted by Ser, reverted the effect of GAS6 on stimulation of VEGF receptor 2 and endothelial chemotaxis triggered by VEGF-A. These studies provide the first demonstration of a cross talk between Axl and VEGF receptor 2 and add new information on the regulation of VEGF-A activities during tissue vascularization.

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Mid-luteal angiogenesis and function in the primate is dependent on vascular endothelial growth factor

Journal of Endocrinology ◽

10.1677/joe.0.1680409 ◽

2001 ◽

Vol 168 (3) ◽

pp. 409-416 ◽

Cited By ~ 50

Author(s):

SE Dickson ◽

R Bicknell ◽

HM Fraser

Keyword(s):

Vascular Endothelial Growth Factor ◽

Endothelial Cells ◽

Endothelial Cell ◽

Growth Factor ◽

Luteal Phase ◽

Smooth Muscle Actin ◽

Proliferation Index ◽

Endothelial Cell Proliferation ◽

Vascular Endothelial ◽

Endothelial Growth Factor

Vascular endothelial growth factor (VEGF) is essential for the angiogenesis required for the formation of the corpus luteum; however, its role in ongoing luteal angiogenesis and in the maintenance of the established vascular network is unknown. The aim of this study was to determine whether VEGF inhibition could intervene in ongoing luteal angiogenesis using immunoneutralisation of VEGF starting in the mid-luteal phase. In addition, the effects on endothelial cell survival and the recruitment of periendothelial support cells were examined. Treatment with a monoclonal antibody to VEGF, or mouse gamma globulin for control animals, commenced on day 7 after ovulation and continued for 3 days. Bromodeoxyuridine (BrdU), used to label proliferating cells to obtain a proliferation index, was administered one hour before collecting ovaries from control and treated animals. Ovarian sections were stained using antibodies to BrdU, the endothelial cell marker, CD31, the pericyte marker, alpha-smooth muscle actin, and 3' end DNA fragments as a marker for apoptosis. VEGF immunoneutralisation significantly suppressed endothelial cell proliferation and the area occupied by endothelial cells while increasing pericyte coverage and the incidence of endothelial cell apoptosis. Luteal function was markedly compromised by anti-VEGF treatment as judged by a 50% reduction in plasma progesterone concentration. It is concluded that ongoing angiogenesis in the mid-luteal phase is primarily driven by VEGF, and that a proportion of endothelial cells of the mid-luteal phase vasculature are dependent on VEGF support.

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Identification and Characterization of Regulator of G Protein Signaling 4 (RGS4) as a Novel Inhibitor of Tubulogenesis: RGS4 Inhibits Mitogen-activated Protein Kinases and Vascular Endothelial Growth Factor Signaling

Molecular Biology of the Cell ◽

10.1091/mbc.e04-06-0479 ◽

2005 ◽

Vol 16 (2) ◽

pp. 609-625 ◽

Cited By ~ 53

Author(s):

Allan R. Albig ◽

William P. Schiemann

Keyword(s):

Endothelial Cells ◽

Endothelial Cell ◽

Growth Factor ◽

G Protein ◽

P38 Mapk ◽

G Protein Signaling ◽

Vascular Endothelial ◽

Protein Signaling ◽

Mapk Activation ◽

Endothelial Growth Factor

Tubulogenesis by epithelial cells regulates kidney, lung, and mammary development, whereas that by endothelial cells regulates vascular development. Although functionally dissimilar, the processes necessary for tubulation by epithelial and endothelial cells are very similar. We performed microarray analysis to further our understanding of tubulogenesis and observed a robust induction of regulator of G protein signaling 4 (RGS4) mRNA expression solely in tubulating cells, thereby implicating RGS4 as a potential regulator of tubulogenesis. Accordingly, RGS4 overexpression delayed and altered lung epithelial cell tubulation by selectively inhibiting G protein-mediated p38 MAPK activation, and, consequently, by reducing epithelial cell proliferation, migration, and expression of vascular endothelial growth factor (VEGF). The tubulogenic defects imparted by RGS4 in epithelial cells, including its reduction in VEGF expression, were rescued by overexpression of constitutively active MKK6, an activator of p38 MAPK. Similarly, RGS4 overexpression abrogated endothelial cell angiogenic sprouting by inhibiting their synthesis of DNA and invasion through synthetic basement membranes. We further show that RGS4 expression antagonized VEGF stimulation of DNA synthesis and extracellular signal-regulated kinase (ERK)1/ERK2 and p38 MAPK activation as well as ERK1/ERK2 activation stimulated by endothelin-1 and angiotensin II. RGS4 had no effect on the phosphorylation of Smad1 and Smad2 by bone morphogenic protein-7 and transforming growth factor-β, respectively, indicating that RGS4 selectively inhibits G protein and VEGF signaling in endothelial cells. Finally, we found that RGS4 reduced endothelial cell response to VEGF by decreasing VEGF receptor-2 (KDR) expression. We therefore propose RGS4 as a novel antagonist of epithelial and endothelial cell tubulogenesis that selectively antagonizes intracellular signaling by G proteins and VEGF, thereby inhibiting cell proliferation, migration, and invasion, and VEGF and KDR expression.

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