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

2010 ◽  
Vol 84 (21) ◽  
pp. 11227-11234 ◽  
Author(s):  
Punya Shrivastava-Ranjan ◽  
Pierre E. Rollin ◽  
Christina F. Spiropoulou

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.

2001 ◽  
Vol 168 (3) ◽  
pp. 409-416 ◽  
Author(s):  
SE Dickson ◽  
R Bicknell ◽  
HM Fraser

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.


Endocrinology ◽  
2008 ◽  
Vol 149 (12) ◽  
pp. 6076-6083 ◽  
Author(s):  
Graham W. Aberdeen ◽  
Stanley J. Wiegand ◽  
Thomas W. Bonagura ◽  
Gerald J. Pepe ◽  
Eugene D. Albrecht

To assess whether there is a link between estrogen, vascular endothelial growth factor (VEGF), and early aspects of uterine angiogenesis, an acute temporal study was conducted in which ovariectomized baboons were pretreated with VEGF Trap, which sequesters endogenous VEGF, and administered estradiol at time 0 h. Serum estradiol levels approximated 500 pg/ml 4–6 h after estradiol administration. VEGF mRNA levels in endometrial glandular epithelial and stromal cells were increased to values 6 h after estradiol that were 3.74 ± 0.99-fold (mean ± se) and 5.70 ± 1.60-fold greater (P < 0.05), respectively, than at 0 h. Microvessel interendothelial cell tight junctions, which control paracellular permeability, were present in the endometrium at time 0 h, but not evident 6 h after estradiol administration. Thus, microvessel paracellular cleft width increased (P < 0.01, ANOVA) from 5.03 ± 0.22 nm at 0 h to 7.27 ± 0.48 nm 6 h after estrogen. In contrast, tight junctions remained intact, and paracellular cleft widths were unaltered in estradiol/VEGF Trap and vehicle-treated animals. Endometrial microvessel endothelial cell mitosis, i.e. percent Ki67+/Ki67− immunolabeled endothelial cells, increased (P < 0.05) from 2.9 ± 0.3% at 0 h to 21.4 ± 7.0% 6 h after estrogen treatment but was unchanged in estradiol/VEGF Trap and vehicle-treated animals. In summary, the estrogen-induced disruption of endometrial microvessel endothelial tight junctions and increase in endothelial cell proliferation were prevented by VEGF Trap. Therefore, we propose that VEGF mediates the estrogen-induced increase in microvessel permeability and endothelial cell proliferation as early steps in angiogenesis in the primate endometrium.


Blood ◽  
2005 ◽  
Vol 105 (5) ◽  
pp. 1992-1999 ◽  
Author(s):  
Matilde Murga ◽  
Oscar Fernandez-Capetillo ◽  
Giovanna Tosato

AbstractNeuropilin-1 (NRP-1) is a type 1 membrane protein that binds the axon guidance factors belonging to the class-3 semaforin family. In endothelial cells, NRP-1 serves as a co-receptor for vascular endothelial growth factor (VEGF) and regulates VEGF receptor 2 (VEGFR-2)–dependent angiogenesis. Although gene-targeting studies documenting embryonic lethality in NRP-1 null mice have demonstrated a critical role for NRP-1 in vascular development, the activities of NRP-1 in mature endothelial cells have been incompletely defined. Using RNA interference-mediated silencing of NRP-1 or VEGFR-2 in primary human endothelial cells, we confirm that NRP-1 modulates VEGFR-2 signaling-dependent mitogenic functions of VEGF. Importantly, we now show that NRP-1 regulates endothelial cell adhesion to extracellular matrix proteins independently of VEGFR-2. Based on its dual role as an enhancer of VEGF activity and a mediator of endothelial cell adhesiveness described here, NRP-1 emerges as a promising molecular target for the development of antiangiogenic drugs.


Blood ◽  
2008 ◽  
Vol 111 (7) ◽  
pp. 3479-3488 ◽  
Author(s):  
Simonetta Soro ◽  
Angela Orecchia ◽  
Lucia Morbidelli ◽  
Pedro Miguel Lacal ◽  
Veronica Morea ◽  
...  

Abstract Vascular endothelial growth factor receptor-1 (VEGFR-1) is a tyrosine kinase receptor for growth factors of the VEGF family. Endothelial cells express a membrane-bound and a soluble variant of this protein, the latter being mainly considered as a negative regulator of VEGF-A signaling. We previously reported that the soluble form is deposited in the extracellular matrix produced by endothelial cells in culture and is able to promote cell adhesion and migration through binding to α5β1 integrin. In this study, we demonstrate that the Ig-like domain II of VEGFR-1, which contains the binding determinants for the growth factors, is involved in the interaction with α5β1 integrin. To identify domain regions involved in integrin binding, we designed 12 peptides putatively mimicking the domain II surface and tested their ability to inhibit α5β1-mediated endothelial cell adhesion to soluble VEGFR-1 and directly support cell adhesion. One peptide endowed with both these properties was identified and shown to inhibit endothelial cell migration toward soluble VEGFR-1 as well. This peptide directly binds α5β1 integrin, but not VEGF-A, inducing endothelial cell tubule formation in vitro and neoangiogenesis in vivo. Alanine scanning mutagenesis of the peptide defined which residues were responsible for its biologic activity and integrin binding.


Blood ◽  
2005 ◽  
Vol 105 (5) ◽  
pp. 1970-1976 ◽  
Author(s):  
Margherita Gallicchio ◽  
Stefania Mitola ◽  
Donatella Valdembri ◽  
Roberto Fantozzi ◽  
Brian Varnum ◽  
...  

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.


Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 521-532 ◽  
Author(s):  
G. Breier ◽  
U. Albrecht ◽  
S. Sterrer ◽  
W. Risau

Vascular endothelial growth factor (VEGF) is a secreted angiogenic mitogen whose target cell specificity appears to be restricted to vascular endothelial cells. Such factors are likely candidates for regulatory molecules involved in endothelial growth control. We have characterized the murine VEGF gene and have analysed its expression pattern in embryogenesis, particularly during brain angiogenesis. Analysis of cDNA clones predicted the existence of three molecular forms of VEGF which differ in size due to heterogeneity at the carboxy terminus of the protein. The predicted mature proteins consist of 120, 164 or 188 amino acid residues. Homodimers of the two lower molecular weight forms, but not of the higher molecular weight form, were secreted by COS cells transfected with the corresponding cDNAs and were equally potent in stimulating the growth of endothelial cells. During brain development, VEGF transcript levels were abundant in the ventricular neuroectoderm of embryonic and postnatal brain when endothelial cells proliferate rapidly but were reduced in the adult when endothelial cell proliferation has ceased. The temporal and spatial expression of VEGF is consistent with the hypothesis that VEGF is synthesized and released by the ventricular neuroectoderm and may induce the ingrowth of capillaries from the perineural vascular plexus. In addition to the transient expression during brain development, a persistent expression of VEGF was observed in epithelial cells adjacent to fenestrated endothelium, e.g. in choroid plexus and in kidney glomeruli. The data are consistent with a role of VEGF as a multifunctional regulator of endothelial cell growth and differentiation.


Sign in / Sign up

Export Citation Format

Share Document