| 1. |
- Cébe-Suarez, Stéphanie, et al.
(författare)
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Orf virus VEGF-E NZ2 promotes paracellular NRP-1/VEGFR-2 coreceptor assembly via the peptide RPPR
- 2008
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 22:8, s. 3078-3086
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factors (VEGFs) interact with the receptor tyrosine kinases (RTKs) VEGFR-1, -2, and -3; neuropilins (NRPs); and heparan sulfate (HS) proteoglycans. VEGF RTKs signal to downstream targets upon ligand-induced tyrosine phosphorylation, while NRPs and HS act as coreceptors that lack enzymatic activity yet modulate signal output by VEGF RTKs. VEGFs exist in various isoforms with distinct receptor specificity and biological activity. Here, a series of mammalian VEGF-A splice variants and orf virus VEGF-Es, as well as chimeric and mutant VEGF variants, were characterized to determine the motifs required for binding to NRP-1 in the absence (VEGF-E) or presence (VEGF-A(165)) of an HS-binding sequence. We identified the carboxyterminal peptides RPPR and DKPRR as the NRP-1 binding motifs of VEGF-E and VEGF-A, respectively. RPPR had significantly higher affinity for NRP-1 than DKPRR. VEGFs containing an RPPR motif promoted HS-independent coreceptor complex assembly between VEGFR-2 and NRP-1, independent of whether these receptors were expressed on the same or separate cells grown in cocultures. Functional studies showed that stable coreceptor assembly by VEGF correlated with its ability to promote vessel formation in an embryoid body angiogenesis assay.
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| 2. |
- Jakobsson, Lars, et al.
(författare)
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Laminin deposition is dispensable for vasculogenesis but regulates blood vessel diameter independent of flow
- 2008
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 22:5, s. 1530-1539
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Tidskriftsartikel (refereegranskat)abstract
- Basement membranes (BMs) consisting of laminins, collagens, and heparan sulfate proteoglycans (HSPGs) are vital for proper endothelial cell function, but many aspects of their role in vascular development remain unknown. Here, we demonstrate that vascular structures within differentiating embryoid bodies are wrapped in a BM composed of alpha 4- and alpha 5-chain laminins, fibronectin, collagen IV, and HSPGs. In sprouting angiogenesis, laminins were produced by stalk cells, as well as the leading tip cell, and deposited along the sprout length, including tip cell filopodia. In embryonic stem cells deficient in laminins, due to lamc1 (laminin gamma 1) deletion, vascular development and organization were largely unaffected. However, the frequency of vessels with wide lumens was increased 4-fold. Laminin-deficient vessels were moreover characterized by increased fibronectin levels and enhanced endothelial cell proliferation. We conclude that laminins are dispensable for vascular development but that they regulate lumen formation in the absence of flow and vascular tone.
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| 3. |
- Lugano, Roberta, et al.
(författare)
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CD93 maintains endothelial barrier function by limiting the phosphorylation and turnover of VE-cadherin
- 2023
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Ingår i: The FASEB Journal. - : John Wiley & Sons. - 0892-6638 .- 1530-6860. ; 37:4
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Tidskriftsartikel (refereegranskat)abstract
- Regulation of vascular permeability to plasma is essential for tissue and organ homeostasis and is mediated by endothelial cell-to-cell junctions that tightly regulate the trafficking of molecules between blood and tissue. The single-pass transmembrane glycoprotein CD93 is upregulated in endothelial cells during angiogenesis and controls cytoskeletal dynamics. However, its role in maintaining homeostasis by regulating endothelial barrier function has not been elucidated yet. Here, we demonstrate that CD93 interacts with vascular endothelial (VE)-cadherin and limits its phosphorylation and turnover. CD93 deficiency in vitro and in vivo induces phosphorylation of VE-cadherin under basal conditions, displacing it from endothelial cell–cell contacts. Consistent with this, endothelial junctions are defective in CD93−/− mice, and the blood–brain barrier permeability is enhanced. Mechanistically, CD93 regulates VE-cadherin phosphorylation and turnover at endothelial junctions through the Rho/Rho kinase-dependent pathway. In conclusion, our results identify CD93 as a key regulator of VE-cadherin stability at endothelial junctions, opening up possibilities for therapeutic strategies directed to control vascular permeability.
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| 4. |
- Mellberg, Sofie, et al.
(författare)
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Transcriptional profiling reveals a critical role for tyrosine phosphatase VE-PTP in regulation of VEGFR2 activity and endothelial cell morphogenesis.
- 2009
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Ingår i: The FASEB journal. - : Wiley. - 1530-6860 .- 0892-6638. ; 23:5, s. 1490-1502
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Tidskriftsartikel (refereegranskat)abstract
- To define molecular events accompanying formation of the 3-dimensional (3D) vascular tube, we have characterized gene expression during vascular endothelial growth factor (VEGF)-induced tubular morphogenesis of endothelial cells. Microarray analyses were performed comparing gene induction in growth-arrested, tube-forming endothelial cells harvested from 3D collagen cultures to that in proliferating endothelial cells cultured on fibronectin. Differentially expressed genes were clustered and analyzed for specific endothelial expression through publicly available datasets. We validated the contribution of one of the identified genes, vascular endothelial protein tyrosine phosphatase (VE-PTP), to endothelial morphogenesis. Silencing of VE-PTP expression was accompanied by increased VEGF receptor-2 (VEGFR2) tyrosine phosphorylation and activation of downstream signaling pathways. The increased VEGFR2 activity promoted endothelial cell cycle progression, overcoming the G(0)/G(1) arrest associated with organization into tubular structures in the 3D cultures. Proximity ligation showed close association between VEGFR2 and VE-PTP in resting cells. Activation of VEGFR2 by VEGF led to rapid loss of association, which was resumed with time in parallel with decreased receptor activity. In conclusion, we have identified genes, which may serve critical functions in formation of the vascular tube. One of these, VE-PTP, regulates VEGFR2 activity thereby modulating the VEGF-response during angiogenesis.
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