PLATELET GLYCOPROTEIN IIb-IIIa-LIKE PROTEINS MEDIATE ENDOTHELIAL CELL ATTACHMENT TO ADHESIVE MATRIX PROTEINS AND ARE UP-REGULATED BY PHORBOL ESTERS

1987 ◽  
Author(s):  
I F Charo ◽  
L A Fitzgerald ◽  
D Meyer ◽  
L S Bekeart ◽  
D R Phillips
Keyword(s):  
Monoclonal Antibody ◽  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Phorbol Esters ◽  
Matrix Proteins ◽  
Platelet Glycoprotein ◽  
Mrna Levels ◽  
Platelet Receptor ◽  
Adhesive Proteins

Human endothelial cells (EC) express glycoproteins that are similar to the platelet glycoprotein IIb-IIIa complex (GP IIb-IIIa), the platelet receptor for adhesive proteins. Although GP IIb—IIIa is abundant in both platelets and EC, its only known function is to mediate platelet aggregation. The present study tests the hypotheses that EC attachment to adhesive proteins in the extracellular matrix is mediated by the GP IIb-IIIa-1ike proteins. Endothelial cells attached well to glass slides that were previously coated with adhesive proteins, but not albumin. To determine whether GP IIb-IIIa was involved, EC adherence was measured in the presence and absence of a GP IIb-IIIa monoclonal antibody (7E3) which inhibits fibrinogen (Fg) binding to platelets. The attachment of EC to Fg and von Willebrand factor (vWf), but not fibronectin (Fn) coated slides, was completely inhibited by 7E3. Attachment to vitronectin was partially inhibited. In contrast, EC attachment to Fn was specifically inhibited by a Fn-receptor antibody. Endothelial cell adherence to vWf was also inhibited by a monoclonal antibody (Mab9) against the GP IIb-IIIa binding domain of vWf, but not by antibodies agains.t other portions of vWf. We have further found that 7E3 disrupts monolayers of endothelial cells by detaching the cells from their extracellular matrix. EC incubated in phorbol myris-tate.acetate (PMA) increase in size and appear more tightly adherent to their extracellular matrix. To determine if PMA increases synthesis of cellular receptors for matrix proteins, we have used cDNA probes to measure the mRNA levels of the large subunit of the Fn-receptor (FnRα) and GP IIIa in EC. After a 4 hour incubation in the presence of PMA (10 nM), there was a 2-fold increase in the mRNA levels of both FnRα and GP IIIa, as well as increased cell spreading on the matrix. We conclude: i) the GP Ilb-IIIa complex in EC is a surface receptor for specific adhesive proteins, and is distinct from the FnR, and ii) both GP IIIa and FnRα synthesis are increased by PMA, which causes a concomittant change in cell morphology.

PERTURBATION OF CULTURED ENDOTHELIAL CELLS ALTERS CELLULAR VON WILLEBRAND FACTOR DISTRIBUTION

1987 ◽  
Author(s):  
J H Reinders ◽  
C L Verweii ◽  
J A V Mourlk ◽  
Ph G de Groot
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Von Willebrand Factor ◽  
Phorbol Esters ◽  
Term Treatment ◽  
Cellular Distribution ◽  
Long Term Treatment ◽  
Von Willebrand ◽  
Willebrand Factor

Endothelial cells, cultured from human umbilical veins, synthesize von Willebrand Factor (vWF), that is stored by the cells in Weibel-Palade bodies, secreted into the medium and incorporated into the extracellular matrix underneath the cells. We have studied the influence of perturbation by phorbol esters and thrombin on the cellular distribution of vWF. Short-term (< 1 hour) treatment of endothelial cells with phorbol ester PMA or thrombin resulted in the release of cellular stored vWF. Long-term treatment with perturbants evoked a distinct change in the endothelial cell distribution of vWF, evident 24 to 48 hours after exposure. While the contents of the vWF storage vesicles were gradually restored within 48 hours, enhanced amounts of vWF were secreted into the medium. However, PMA did not increase the endothelial cell contents of mRNA encoding for vWF. The number as well as the size of vWF storage granules in the cells increased after exposure to perturbants. The perturbed cells responded to stimuli in releasing stored vWF, the amounts secreted were even greater than those in control cells. The extracellular matrix lost its vWF contents as the result of PMA or thrombin treatment, by blocking deposition of vWF in the matrix, not by enhancing degradation of matrix vWF. In perfusion experiments, the adhesion of washed platelets onto the isolated matrix of perturbed cells was considerable less than that in controls. Addition of vWF to the perfusate overcame this impairment. Thus, perturbation of endothelial cells changes the cellular distribution of vWF.Supported in part by ZWO grants 13-30-31 and 13-90-91 and Netherlands Heart Foundation grant 28.004.

Von Willebrand Factor Binds to the Endothelial Growth Factor Angiopoietin-2 Both within Endothelial Cells and Upon Release From Weibel Palade Bodies

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 698-698 ◽  
Author(s):  
Thomas A J Mckinnon ◽  
Richard D Starke ◽  
Kushani Ediriwickrema ◽  
Anna Maria Randi ◽  
Michael Laffan
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Extracellular Matrix Proteins ◽  
Matrix Proteins ◽  
Dependent Manner ◽  
Platelet Receptor ◽  
Angiopoietin 2 ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Abstract 698 Von Willebrand Factor (VWF) is a large multimeric plasma glycoprotein essential for homeostasis, also involved in inflammation and angiogenesis. The majority of VWF is synthesised by endothelial cells (EC) and is either constitutively secreted or stored in Weibel-Palade bodies (WPB), ready to be released in response to endothelial stimulation. Several studies have shown that formation of WPB is dependent on the presence of VWF, and deletion of VWF in human umbilical vein EC (HUVEC) results in loss of WPB. Amongst the other proteins shown to co-localise to WPB is angiopoietin-2 (Ang2), a ligand of the receptor tyrosine kinase Tie-2. Ang2 regulates endothelial cell survival, vascular stability and maturation, by destabilizing quiescent endothelium and facilitating the response to inflammatory and angiogenic stimuli. VWF is required for storage of Ang2, and release of Ang-2 from EC is increased in VWF-deficient HUVEC. Recently, we have shown that VWF itself regulates angiogenesis, raising the hypothesis that some of the angiogenic activity of VWF may be mediated by Ang-2. In the present study we investigated the interaction between Ang2 and VWF. Binding analysis demonstrated that recombinant human Ang2 bound to purified plasma-derived VWF in a pH and calcium dependent manner, with optimal binding occurring at pH 6.5 and 10mM calcium, indicative of binding within the Golgi body. Generation of binding isotherms established that Ang2 bound to VWF with high affinity (KD∼3nM); furthermore binding affinity was not dependent on VWF conformation. Using an array of VWF constructs we determined that Ang2 bound predominantly to the VWF A1 domain, which also contains binding sites to the platelet receptor GPIb and extracellular matrix proteins. Co-immunoprecipitation experiments performed on TNFα- and ionomycin-stimulated HUVECs, to induce WPB exocytosis, confirmed that a portion of Ang2 remained bound to secreted VWF. Moreover, immunofluorescence staining of histamine-stimulated HUVECs to induce VWF release demonstrated the presence of Ang2 on VWF strings secreted from ECs. Finally we demonstrated that Ang2 bound to VWF was still able to interact with Tie-2. These data demonstrate that binding of Ang2 to VWF occurs within the cell; we propose that this is the mechanism mediating storage of Ang2 in WPB. Moreover, the finding that the Ang2-VWF interaction is preserved following secretion raises the intriguing possibility VWF may affect Ang2 function, possibly by localising Ang2 to the Tie 2 receptor under the shear forces experienced in flowing blood. Similarly, Ang-2 binding to VWF may modulate its interaction with receptors and extracellular matrix proteins, and ultimately influence the role of VWF in the angiogenic processes. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Aberrant production of extracellular matrix proteins and dysfunction in kidney endothelial cells with a short duration of diabetes

2013 ◽  
Vol 304 (1) ◽  
pp. F19-F30 ◽  
Author(s):  
Cathy Grutzmacher ◽  
SunYoung Park ◽  
Yun Zhao ◽  
Margaret E. Morrison ◽  
Nader Sheibani ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Diabetic Nephropathy ◽  
Endothelial Cell ◽  
Short Duration ◽  
Cell Function ◽  
Matrix Proteins ◽  
Endothelial Cell Function ◽  
Duration Of Diabetes ◽  
Akita Mice

Diabetic nephropathy is the most common cause of end-stage renal disease and is a major risk factor for cardiovascular disease. In the United States, microvascular complications during diabetic nephropathy contribute to high morbidity and mortality rates. However, the cell-autonomous impact of diabetes on kidney endothelial cell function requires further investigation. Male Akita/+ [autosomal dominant mutation in the insulin II gene (Ins2)] mice reproducibly develop diabetes by 4 wk of age. Here, we examined the impact a short duration of diabetes had on kidney endothelial cell function. Kidney endothelial cells were prepared from nondiabetic and diabetic mice (4 wk of diabetes) to delineate the early changes in endothelial cell function. Kidney endothelial cells from Akita/+ mice following 4 wk of diabetes demonstrated aberrant expression of extracellular matrix proteins including decreased osteopontin and increased fibronectin expression which correlated with increased α5-integrin expression. These changes were associated with the attenuation of migration and capillary morphogenesis. Kidney endothelial cells from Akita/+ mice had decreased VEGF levels but increased levels of endothelial nitric oxide synthase(eNOS) and NO, suggesting uncoupling of VEGF-mediated NO production. Knocking down eNOS expression in Akita/+ kidney endothelial cells increased VEGF expression, endothelial cell migration, and capillary morphogenesis. Furthermore, attenuation of sprouting angiogenesis of aortas from Akita/+ mice with 8 wk of diabetes was restored in the presence of the antioxidant N-acetylcysteine. These studies demonstrate that aberrant endothelial cell function with a short duration of diabetes may set the stage for vascular dysfunction and rarefaction at later stages of diabetes.

Improved Adhesion and Proliferation of Human Endothelial Cells on Polyethylene Precoated with Monoclonal Antibodies Directed against Cell Membrane Antigens and Extracellular Matrix Proteins

1991 ◽  
Vol 66 (06) ◽  
pp. 715-724 ◽  
Author(s):  
Albert Dekker ◽  
André A Poot ◽  
Jan A van Mourik ◽  
Martin P A Workel ◽  
Tom Beugeling ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Monoclonal Antibodies ◽  
Endothelial Cell ◽  
Platelet Reactivity ◽  
Extracellular Matrix Proteins ◽  
Matrix Proteins ◽  
Specific Monoclonal Antibody ◽  
Human Endothelial Cells ◽  
Membrane Antigens

SummaryEndothelial cell seeding may improve the patency of synthetic vascular grafts provided that platelet reactivity of non-endothelialized sites is not increased. We have investigated if surface-adsorbed monoclonal antibodies directed against endothelial cell membrane proteins and against extracellular matrix proteins promote the adhesion and proliferation of cultured human endothelial cells, without causing platelet deposition at non-endothelialized sites. Adhesion of endothelial cells onto polyethylene coated with monoclonal antibodies directed against endothelial cell-specific membrane antigens, integrin receptors and glycoprotein CD31 was equal to or higher than adhesion onto fibronectin-coated polyethylene. Endothelial cells did not proliferate on these surface-adsorbed antibodies. However, pre-coating of polyethylene with mixtures of endothelial cell-specific monoclonal antibodies and monoclonal antibodies directed against fibronectin or von Willebrand factor, resulted in relatively high adhesion and optimal proliferation. Platelet reactivity of the polyethylene surface was found to significantly increase after adsorption of fibronectin, endothelial cell-specific monoclonal antibody or its Fc fragments. In contrast, adsorption of F(ab')2 fragments of endothelial cell-specific monoclonal antibody did not promote platelet deposition. Therefore, it is concluded that coating of vascular graft materials with mixtures of F(ab')2 fragments of monoclonal antibodies specifically directed against endothelial cells and against extracellular matrix proteins may be an effective way to both promote the growth of seeded endothelial cells and limit platelet-graft interaction.

Endothelial cell regulation of matrix metalloproteinases

2005 ◽  
Vol 83 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Tara L Haas
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Matrix Metalloproteinases ◽  
Basement Membrane ◽  
Matrix Proteins ◽  
Regulation Of Transcription ◽  
Cell Type ◽  
Sprouting Angiogenesis

The process of sprouting angiogenesis requires that the endothelial cells degrade the basement membrane matrix and migrate into the interstitial matrix. Matrix metalloproteinases are enzymes capable of cleaving numerous extracellular matrix proteins. Increased production and activity of matrix metalloproteinases in any cell type is associated with a more migratory and invasive phenotype. This paper describes results of recent in-vitro studies of the regulation of transcription and activation of MMP-2 and MT1-MMP in endothelial cells, as well as studies that examined roles of matrix metalloproteinases in activity-induced angiogenesis.Key words: proteolysis, extracellular matrix, angiogenesis, mechanotransduction.

Immunoelectrophoretic Analysis of Membrane Glycoproteins in Cultured Human Endothelial Cells

1990 ◽  
Vol 63 (02) ◽  
pp. 303-311
Author(s):  
Tone Børsum
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Rabbit Antiserum ◽  
Platelet Glycoprotein ◽  
Membrane Glycoproteins ◽  
Human Endothelial Cells ◽  
Immunoelectrophoretic Analysis ◽  
Glycoprotein Complex ◽  
Crossed Immunoelectrophoresis ◽  
Triton X

SummaryHuman endothelial cells isolated from umbilical cordswere solubilized in Triton X-100 and examined by crossedimmunoelec-trophoresis using rabbit antiserum against endothelial cells. Endogenous labelling of the endothelialcell proteins with 14Cmannose followed by crossed immunoelectrophoresis and autoradiography revealed about 10 immunoprecipitates. Four of these endothelial cell glycoproteins were labelled by lactoperoxidase catalyzed iodination and thus were surface located. Three of the surface located glycoproteins showed reduced electrophoretic mobility after incubation of the endothelial cells with neuraminidase and were therefore sialoglycoproteins. Amphiphilicity of endothelial cell glycoproteins was studied by crossed hydrophobic interaction immunoelectrophoresis with phenyl-Sepharose in the intermediate gel. Amphiphilic proteins also show increasing electrophoretic migration velocity with decreasing concentration of Triton X-100 in the first dimension gels. Five of the endothelial cell glycoproteins were shown to be amphiphilic using these two techniques.Two monoclonal antibodies against the platelet glycoprotein complex Ilb-IIIa and glycoprotein IlIa, respectively, reacted with the same precipitate of endothelial cells. When a polyclonal antibody against the platelet glycoprotein complex Ilb-IIIa was incorporated into the intermediate gel the position of two endothelial cell precipitates were lowered. One of these was a sialoglycoprotein.

Clues for Understanding the Structure and Function of a Prototypic Human Integrin: The Platelet Glycoprotein IIb/IIIa Complex

1994 ◽  
Vol 72 (01) ◽  
pp. 001-015 ◽  
Author(s):  
Juan J Calvete
Keyword(s):  
Structure Function ◽  
Thrombus Formation ◽  
Platelet Glycoprotein ◽  
Primary Role ◽  
Clot Retraction ◽  
Inhibitory Peptide ◽  
Rgd Sequence ◽  
Platelet Receptor ◽  
Adhesive Proteins ◽  
And Function

SummaryThe glycoprotein (GP) IIb/IIIa, a Ca2+-dependent heterodimer, is the major integrin on the platelet plasma membrane. On resting platelets GPIIb/IIIa is maintained in an inactive conformation and serves as a low affinity adhesion receptor for surface-coated fibrinogen, whereas upon platelet activation signals within the cytoplasma alter the receptor function of GPIIb/IIIa (inside-out signalling), which undergoes a measurable conformational change within its exoplasmic domains, and becomes a competent receptor for soluble fibrinogen and some other RGD sequence-containing plasma adhesive proteins. Upon ligand binding, further structural alterations trigger the association of receptor-occupied GPIIb/IIIa complexes with themselves within the plane of the membrane. The simultaneous binding of dimeric fibrinogen molecules to GPIIb/IIIa clusters on adjacent platelets leads to platelet aggregation, which promotes attachment of fibrinogen-GPIIb/IIIa clusters to the cytoskeleton (outside-in signalling). This, in turn, provides the necessary physical link for clot retraction to occur, and generates a cascade of intracellular biochemical reactions which result in the formation of a multiprotein signalling complex at the cytoplasmic domains of GPIIb/IIIa. Glycoprotein IMIIa, also called αIIbβ3 in the integrin nomenclature, plays thus a primary role in both platelet adhesion and thrombus formation at the site of vascular injury. In addition, the human glycoprotein Ilb/IIIa complex is the most thoroughly studied integrin receptor, its molecular biology and major features of its primary structure having been elucidated mainly during the last six years. Furthermore, localization of functionally relevant monoclonal antibody epitopes, determination of the cross-linking sites of inhibitory peptide ligands, proteolytic dissection of the isolated integrin, and analysis of natural and artificial GPIIb/IIIa mutants have recently provided a wealth of information regarding structure-function relationships of human GPIIb/IIIa. The aim of this review is to summarize these many structural and functional data in the perspective of an emerging model. Although most of the interpretations based on structural elements of this initial biochemical model require independent confirmation, they may help us to understand the structure-function relationship of this major platelet receptor, and of other members of the integrin superfamily, as well as to perform further investigations in order to test current hypotheses.

Naturally Produced Extracellular Matrix Is an Excellent Substrate for Canine Endothelial Cell Proliferation and Resistance to Shear Stress on PTFE Vascular Grafts

1997 ◽  
Vol 78 (05) ◽  
pp. 1392-1398 ◽  
Author(s):  
A Schneider ◽  
M Chandra ◽  
G Lazarovici ◽  
I Vlodavsky ◽  
G Merin ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Cell ◽  
Cell Attachment ◽  
Thrombus Formation ◽  
Endothelial Cell Proliferation ◽  
Ptfe Graft ◽  
Vascular Prostheses ◽  
Endothelial Cell Attachment

SummaryPurpose: Successful development of a vascular prosthesis lined with endothelial cells (EC) may depend on the ability of the attached cells to resist shear forces after implantation. The present study was designed to investigate EC detachment from extracellular matrix (ECM) precoated vascular prostheses, caused by shear stress in vitro and to test the performance of these grafts in vivo. Methods: Bovine aortic endothelial cells were seeded inside untreated polytetrafluoro-ethylene (PTFE) vascular graft (10 X 0.6 cm), PTFE graft precoated with fibronectin (FN), or PTFE precoated with FN and a naturally produced ECM (106 cells/graft). Sixteen hours after seeding the medium was replaced and unattached cells counted. The strength of endothelial cell attachment was evaluated by subjecting the grafts to a physiologic shear stress of 15 dynes/cm2 for 1 h. The detached cells were collected and quantitated. PTFE or EC preseeded ECM coated grafts were implanted in the common carotid arteries of dogs. Results: While little or no differences were found in the extent of endothelial cell attachment to the various grafts (79%, 87% and 94% of the cells attached to PTFE, FN precoated PTFE, or FN+ECM precoated PTFE, respectively), the number of cells retained after a shear stress was significanly increased on ECM coated PTFE (20%, 54% and 85% on PTFE, FN coated PTFE, and FN+ECM coated PTFE, respectively, p <0.01). Implantation experiments in dogs revealed a significant increase in EC coverage and a reduced incidence of thrombus formation on ECM coated grafts that were seeded with autologous saphenous vein endothelial cells prior to implantation. Conclusion: ECM coating significantly increased the strength of endothelial cell attachment to vascular prostheses subjected to shear stress. The presence of adhesive macromolecules and potent endothelial cell growth promoting factors may render the ECM a promising substrate for vascular prostheses.

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