Chronic hypoxia attenuates VEGF signaling and angiogenic responses by downregulation of KDR in human endothelial cells

2009 ◽  
Vol 296 (5) ◽  
pp. C1162-C1170 ◽  
Author(s):  
Barbara Olszewska-Pazdrak ◽  
Travis W. Hein ◽  
Paulina Olszewska ◽  
Darrell H. Carney
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Coronary Artery ◽  
Chronic Hypoxia ◽  
Tube Formation ◽  
Endothelial Cell Migration ◽  
No Production ◽  
Vegf Receptor ◽  
Human Coronary Artery ◽  
Vegf Signaling

Coronary artery disease results in progressive vascular stenosis associated with chronic myocardial ischemia. Vascular endothelial growth factor (VEGF) stimulates endothelial cell angiogenic responses to revascularize ischemic tissues; however, the effect of chronic hypoxia on the responsiveness of endothelial cells to VEGF remains unclear. We, therefore, investigated whether hypoxia alters VEGF-stimulated signaling and angiogenic responses in primary human coronary artery endothelial (HCAE) cells. Exposure of HCAE cells to hypoxia (1% O2) for 24 h decreased VEGF-stimulated endothelial cell migration (∼82%), proliferation (∼30%), and tube formation. Hypoxia attenuated VEGF-stimulated activation of endothelial nitric oxide (NO) synthase (eNOS) (∼72%) and reduced NO production in VEGF-stimulated cells from 237 ± 38.8 to 61.3 ± 28.4 nmol/l. Moreover, hypoxia also decreased the ratio of phosphorylated eNOS to total eNOS in VEGF-stimulated cells by ∼50%. This effect was not observed in thrombin-stimulated cells, suggesting that hypoxia specifically inhibited VEGF signaling upstream of eNOS phosphorylation. VEGF-induced activation of Akt, ERK1/2, p38, p70S6 kinases, and S6 ribosomal protein was also attenuated in hypoxic cells. Moreover, VEGF-stimulated phosphorylation of VEGF receptor-2 (KDR) at Y996 and Y1175 was decreased by hypoxia. This decrease correlated with a 70 ± 12% decrease in KDR protein expression. Analysis of mRNA from these cells showed that hypoxia reduced steady-state levels of KDR mRNA by 52 ± 16% and decreased mRNA stability relative to normoxic cells. Our findings demonstrate that chronic hypoxia attenuates VEGF-stimulated signaling in HCAE cells by specific downregulation of KDR expression. These data provide a novel explanation for the impaired angiogenic responses to VEGF in endothelial cells exposed to chronic hypoxia.

Abstract 117: RhoC Regulates VEGF-induced Signaling in Endothelial Cells

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Luke Hoeppner ◽  
Sutapa Sinha ◽  
Ying Wang ◽  
Resham Bhattacharya ◽  
Shamit Dutta ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Vascular Permeability ◽  
Rho Gtpase ◽  
Endothelial Cell Migration ◽  
Calcium Flux ◽  
Endothelial Cell Proliferation ◽  
Vegf Receptor ◽  
Vegf Signaling

Vascular permeability factor/vascular endothelial growth factor A (VEGF) is a central regulator of angiogenesis and potently promotes vascular permeability. VEGF plays a key role in the pathologies of heart disease, stroke, and cancer. Therefore, understanding the molecular regulation of VEGF signaling is an important pursuit. Rho GTPase proteins play various roles in vasculogenesis and angiogenesis. While the functions of RhoA and RhoB in these processes have been well defined, little is known about the role of RhoC in VEGF-mediated signaling in endothelial cells and vascular development. Here, we describe how RhoC modulates VEGF signaling to regulate endothelial cell proliferation, migration and permeability. We found VEGF stimulation activates RhoC in human umbilical vein endothelial cells (HUVECs), which was completely blocked after VEGF receptor 2 (VEGFR-2) knockdown indicating that VEGF activates RhoC through VEGFR-2 signaling. Interestingly, RhoC knockdown delayed the degradation of VEGFR-2 compared to control siRNA treated HUVECs, thus implicating RhoC in VEGFR-2 trafficking. In light of our results suggesting VEGF activates RhoC through VEGFR-2, we sought to determine whether RhoC regulates vascular permeability through the VEGFR-2/phospholipase Cγ (PLCγ) /Ca 2+ /eNOS cascade. We found RhoC knockdown in VEGF-stimulated HUVECs significantly increased PLC-γ1 phosphorylation at tyrosine 783, promoted basal and VEGF-stimulated eNOS phophorylation at serine 1177, and increased calcium flux compared with control siRNA transfected HUVECs. Taken together, our findings suggest RhoC negatively regulates VEGF-induced vascular permeability. We confirmed this finding through a VEGF-inducible zebrafish model of vascular permeability by observing significantly greater vascular permeability in RhoC morpholino (MO)-injected zebrafish than control MO-injected zebrafish. Furthermore, we showed that RhoC promotes endothelial cell proliferation and negatively regulates endothelial cell migration. Our data suggests a scenario in which RhoC promotes proliferation by upregulating -catenin in a Wnt signaling-independent manner, which in turn, promotes Cyclin D1 expression and subsequently drives cell cycle progression.

Abstract P211: N-Acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) Promotes Tube Formation in Human Coronary Artery Endothelial Cells

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Ginette Bordcoch ◽  
Pablo Nakagawa ◽  
Cesar A Romero ◽  
Oscar A Romero
Keyword(s):  
Endothelial Cells ◽  
Coronary Artery ◽  
Capillary Tube ◽  
Tube Formation ◽  
Endothelial Cell Migration ◽  
Tube Length ◽  
Human Coronary Artery ◽  
Double Phase ◽  
Angiogenic Effect

Ac-SDKP is an endogenous peptide with anti-inflammation and anti-fibrotic effects in hypertensive and cardiovascular diseases. It is cleaved from Thymosin β4 (Tβ4) and hydrolyzed by angiotensin converting enzyme (ACE). Ac-SDKP plasma concentration increases after treatment with ACE inhibitors (ACEi) and some of the beneficial effects of ACEi treatment has been ascribed to Ac-SDKP. Ac-SDKP is a mediator of angiogenesis in in-vitro and in-vivo animal models. Ac-SDKP stimulates rodents derived immortalized aortic endothelial cells migration and capillary-like structures formation (tube formation). Similarly, Ac-SDKP increases capillary density after myocardial infarction in rats. The mechanism related to angiogenesis induced by Ac-SDKP is not known. Tβ4 (Ac-SDKP precursor) promotes endothelial cell migration and angiogenesis by the activation of the VEGF/AKT pathway. Our objective is to evaluate the Ac-SDKP pro-angiogenic effect in Human Coronary Artery Endothelial Cells (HCAEC) and the mechanism that regulates the angiogenic effect of Ac-SDKP. HCAEC do not produce VEGF, thus we hypothesize that Ac-SDKP increases VEGF expression in fibroblasts and that indirectly could promote capillary tube formation in endothelial cells. We used primary culture of rat cardiac fibroblast (RCF) and we treated these cells with 10nM Ac-SDKP for 24 hours. VEGF concentration in cell supernatant was measured by ELISA. Cells were starved without serum overnight before the Ac-SDKP treatment. For capillary tube formation assay, HCAEC cells were seeded into matrigel and incubated in presence of 10nM Ac-SDKP for 12 hours, pictures were taken by double phase contrast microscope and tube length was quantified with image J software and the results were expressed as percentage of control. After Ac-SDKP treatment, VEGF concentration did not increase in the supernatant of RCF (control: 0.12±0.07 vs. Ac-SDKP: 0.14±0.09 mg/ml; p=0.7). However, Ac-SDKP treatment induced the development of tube formation in HCAECs by 7±2% respect to control (p=0.037). We conclude that Ac-SDKP induces capillary tube formation not only in rodent but also in human derived endothelial cells. The mechanism by which Ac-SDKP promotes tube formation in HCAECs is still unknown.

scholarly journals Adenosine triphosphate is a critical determinant for VEGFR signal during hypoxia

2016 ◽  
Vol 311 (6) ◽  
pp. C985-C995 ◽  
Author(s):  
Abdullah Al Mamun ◽  
Hisaki Hayashi ◽  
Miho Sakima ◽  
Motohiko Sato
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Signal Propagation ◽  
Tube Formation ◽  
Activation Process ◽  
Vegf Receptor ◽  
Vegf Mrna ◽  
Critical Determinant ◽  
Hypoxia Exposure ◽  
Vegf Signaling

Hypoxia induces angiogenesis through the VEGF signaling pathway; however, signal propagation of VEGF in hypoxia is not fully understood. In this study, we examined alterations in VEGF signaling during hypoxia conditions and its determinant in endothelial cells. To analyze VEGF signaling during hypoxia, human umbilical vein endothelial cells (HUVECs) were exposed to 3 h of hypoxia (1% O2) followed by 3 h of reoxygenation or 12 h of hypoxia. Hypoxia induced expression of VEGF mRNA, but it was not associated with an increase in tube formation by HUVECs. During 3 h of hypoxia, VEGF-induced phosphorylation of VEGF receptor-2 (VEGFR-2) and downstream molecules were significantly inhibited without a change in VEGFR-2 expression, but it was completely restored after reoxygenation. VEGF-mediated VEGFR-2 phosphorylation is associated with a reduction in cellular ATP in hypoxia conditions (65.93 ± 8.32% of normoxia, means ± SE, P < 0.01). Interestingly, attenuation of VEGFR-2 phosphorylation was restored by addition of ATP to prepared membranes from cells that underwent 3 h of hypoxia. In contrast to 3 h of hypoxia, exposure of cells to 12 h of hypoxia decreased VEGFR-2 expression and VEGF-mediated VEGFR-2 phosphorylation. The magnitude of VEGFR-2 phosphorylation was not fully restored by addition of ATP to prepared membranes from cells exposed to 12 h of hypoxia. These data indicate that ATP is an important determinant of VEGF signaling in hypoxia and suggest that the activation process of VEGFR-2 was modified by sustained hypoxia. These observations contribute to our understanding of signal alterations in VEGF in endothelial cells during hypoxia.

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.

scholarly journals The GEF Trio controls endothelial cell size and arterial remodeling downstream of Vegf signaling in both zebrafish and cell models

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Alina Klems ◽  
Jos van Rijssel ◽  
Anne S. Ramms ◽  
Raphael Wild ◽  
Julia Hammer ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Large Diameter ◽  
Small Diameter ◽  
Focal Adhesions ◽  
Cell Periphery ◽  
Vegf Receptor ◽  
Cell Models ◽  
Vegf Signaling ◽  
Arterial Lumen

Abstract Arterial networks enlarge in response to increase in tissue metabolism to facilitate flow and nutrient delivery. Typically, the transition of a growing artery with a small diameter into a large caliber artery with a sizeable diameter occurs upon the blood flow driven change in number and shape of endothelial cells lining the arterial lumen. Here, using zebrafish embryos and endothelial cell models, we describe an alternative, flow independent model, involving enlargement of arterial endothelial cells, which results in the formation of large diameter arteries. Endothelial enlargement requires the GEF1 domain of the guanine nucleotide exchange factor Trio and activation of Rho-GTPases Rac1 and RhoG in the cell periphery, inducing F-actin cytoskeleton remodeling, myosin based tension at junction regions and focal adhesions. Activation of Trio in developing arteries in vivo involves precise titration of the Vegf signaling strength in the arterial wall, which is controlled by the soluble Vegf receptor Flt1.

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 Density enhanced phosphatase-1 down-regulates urokinase receptor surface expression in confluent endothelial cells

Blood ◽  
2011 ◽  
Vol 117 (15) ◽  
pp. 4154-4161 ◽  
Author(s):  
Patrick M. Brunner ◽  
Patricia C. Heier ◽  
Judit Mihaly-Bison ◽  
Ute Priglinger ◽  
Bernd R. Binder ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Endothelial Cell Migration ◽  
Cell Surface Receptor ◽  
Migration And Invasion ◽  
Cell Behavior ◽  
Vegf Receptor ◽  
Receptor System ◽  
Upar Expression

Abstract VEGF165, the major angiogenic growth factor, is known to activate various steps in proangiogenic endothelial cell behavior, such as endothelial cell migration and invasion, or endothelial cell survival. Thereby, the urokinase-type plasminogen activator (uPA) system has been shown to play an essential role not only by its proteolytic capacities, but also by induction of intracellular signal transduction. Therefore, expression of its cell surface receptor uPAR is thought to be an essential regulatory mechanism in angiogenesis. We found that uPAR expression on the surface of confluent endothelial cells was down-regulated compared with subconfluent proliferating endothelial cells. Regulation of uPAR expression was most probably affected by extracellular signal-regulated kinase 1/2 (ERK1/2) activation, a downstream signaling event of the VEGF/VEGF-receptor system. Consistently, the receptor-like protein tyrosine phosphatase DEP-1 (density enhanced phosphatase-1/CD148), which is abundantly expressed in confluent endothelial cells, inhibited the VEGF-dependent activation of ERK1/2, leading to down-regulation of uPAR expression. Overexpression of active ERK1 rescued the DEP-1 effect on uPAR. That DEP-1 plays a biologic role in angiogenic endothelial cell behavior was demonstrated in endothelial cell migration, proliferation, and capillary-like tube formation assays in vitro.

scholarly journals Crocus Sativus and Its Active Compound, Crocin Inhibits the Endothelial Activation and Monocyte-Endothelial Cells Interaction in Stimulated Human Coronary Artery Endothelial Cells

2020 ◽  
Author(s):  
Noor Alicezah Mohd Kasim ◽  
Nurul Ain Abu Bakar ◽  
Radzi Ahmad ◽  
Iman Nabilah Abd Rahim ◽  
Thuhairah Hasrah Abdul Rahman ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Coronary Artery ◽  
Endothelial Activation ◽  
Crocus Sativus ◽  
Cellular Interactions ◽  
Human Coronary Artery ◽  
Gene Expressions ◽  
Protein Expressions

AbstractCrocus sativus L. or saffron has been shown to have anti-atherogenic effects. However, its effects on key events in atherogenesis such as endothelial activation and monocyte-endothelial cell binding in lipolysaccharides (LPS)-stimulated in vitro model have not been extensively studied.ObjectivesTo investigate the effects of saffron and its bioactive derivative crocin on the gene and protein expressions of biomarkers of endothelial activation in LPS stimulated human coronary artery endothelial cells (HCAECs).MethodologyHCAECs were incubated with different concentrations of aqueous ethanolic extracts of saffron and crocin together with LPS. Protein and gene expressions of endothelial activation biomarkers were measured using ELISA and qRT-PCR, respectively. Adhesion of monocytes to HCAECs was detected by Rose Bengal staining. Methyl-thiazol-tetrazolium assay was carried out to assess cytotoxicity effects of saffron and crocin.ResultsSaffron and crocin up to 25.0 and 1.6 μg/ml respectively exhibited >85% cell viability. Saffron treatment reduced sICAM-1, sVCAM-1 and E-selectin proteins (concentrations: 3.13, 6.25, 12.5 and 25.0 μg/ml; 3.13, 12.5 and 25.0 μg/ml; 12.5 and 25.0, respectively) and gene expressions (concentration: 12.5 and 25.0μg/ml; 3.13, 6.25 and 25.0 μg/ml; 6.25, 12.5 25.0; respectively). Similarly, treatment with crocin reduced protein expressions of sICAM-1, sVCAM-1 and E-selectin (concentration: 0.2, 0.4, 0.8 and 1.6 μg/ml; 0.4, 0.8 and 1.6 μg/ml; 0.8 and 1.6 μg/ml; respectively] and gene expression (concentration: 0.8 and 1.6 μg/ml; 0.4, 0.8 and 1.6 μg/ml; and 1.6 μg/ml, respectively). Monocyte-endothelial cell interactions were reduced following saffron treatment at concentrations 6.3, 12.5 and 25.00 μg/ml. Similarly, crocin also suppressed cellular interactions at concentrations 0.04, 0.08, 1.60 μg/ml.ConclusionSaffron and crocin exhibits potent inhibitory action for endothelial activation and monocyte-endothelial cells interaction suggesting its potential anti-atherogenic properties.

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