Expression of von Willebrand Factor by Human Pulmonary Endothelial Cells in vivo1

Respiration ◽  
2002 ◽  
Vol 69 (6) ◽  
pp. 526-533 ◽  
Author(s):  
Annette M. Müller ◽  
Carmen Skrzynski ◽  
Guido Skipka ◽  
Klaus-Michael Müller
Keyword(s):  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Pulmonary Endothelial Cells ◽  
Von Willebrand ◽  
Willebrand Factor

Epinephrine Induces von Willebrand Factor Release from Cultured Endothelial Cells: Involvement of Cyclic AMP-dependent Signalling in Exocytosis

1997 ◽  
Vol 77 (06) ◽  
pp. 1182-1188 ◽  
Author(s):  
Ulrich M Vischer ◽  
Claes B Wollheinn
Keyword(s):  
Endothelial Cells ◽  
Adenylate Cyclase ◽  
Von Willebrand Factor ◽  
Umbilical Vein ◽  
Free Calcium ◽  
Camp Content ◽  
Von Willebrand ◽  
Willebrand Factor

Summaryvon Willebrand factor (vWf) is released from endothelial cell storage granules after stimulation with thrombin, histamine and several other agents that induce an increase in cytosolic free calcium ([Ca2+]i). In vivo, epinephrine and the vasopressin analog DDAVP increase vWf plasma levels, although they are thought not to induce vWf release from endothelial cells in vitro. Since these agents act via a cAMP-dependent pathway in responsive cells, we examined the role of cAMP in vWf secretion from cultured human umbilical vein endothelial cells. vWf release increased by 50% in response to forskolin, which activates adenylate cyclase. The response to forskolin was much stronger when cAMP degradation was blocked with IBMX, an inhibitor of phosphodiesterases (+200%), whereas IBMX alone had no effect. vWf release could also be induced by the cAMP analogs dibutyryl-cAMP (+40%) and 8-bromo-cAMP (+25%); although their effect was weak, they clearly potentiated the response to thrombin. Epinephrine (together with IBMX) caused a small, dose-dependent increase in vWf release, maximal at 10-6 M (+50%), and also potentiated the response to thrombin. This effect is mediated by adenylate cyclase-coupled β-adrenergic receptors, since it is inhibited by propranolol and mimicked by isoproterenol. In contrast to thrombin, neither forskolin nor epinephrine caused an increase in [Ca2+]j as measured by fura-2 fluorescence. In addition, the effects of forskolin and thrombin were additive, suggesting that they act through distinct signaling pathways. We found a close correlation between cellular cAMP content and vWf release after stimulation with epinephrine and forskolin. These results demonstrate that cAMP-dependent signaling events are involved in the control of exocytosis from endothelial cells (an effect not mediated by an increase in [Ca2+]i) and provide an explanation for epinephrine-induced vWf release.

DIVERGENT PATES OF VON WILLEBRAND FACTOR AND ITS PROPOLYPEPTIDE (VON WILLEBRAND ANTIGEN II) AFTER SECRETION FROM ENDOTHELIAL CELLS

1987 ◽  
Author(s):  
D D Wagner ◽  
P J Fay ◽  
L A Sporn ◽  
S Sinha ◽  
S O Lawrence ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Culture Medium ◽  
Platelet Adhesion ◽  
Human Foreskin Fibroblasts ◽  
Covalently Linked ◽  
Von Willebrand ◽  
Willebrand Factor

The intracellular site of cleavage of pro-von Willebrand factor subunit and the subsequent fate of the propolypeptide (von Willebrand antigen II) and of the mature von Willebrand factor (vWf) were investigated. Both the propolypeptide, which was found to be a homodimer of non-covalently linked subunits, and mature vWf were released from Weibel-Palade bodies of endothelial cells following stimulation with secretagogues. The stoichiometry of the two proteins in the releasate was essentially equimolar. This indicates that vWf and the propolypeptide were packaged into the Weibel-Palade bodies as one unit, pro-vWf, and that the proteolytic cleavage of pro-vWf is likely to be a post-Golgi event. The association of prosequences into dimers provides support for their hypothetical role in the multimerization process. After secretion, the two proteins were distributed differently, as based on the following observations. The propolypeptide did not associate with vWf in the culture medium, did not co-distribute with vWf in the extracellular "patches of release" on stimulated endothelial cells, and was not detected in the endothelial cell extracellular matrix, which did contain vWf. Additionally, in contrast to vWf, the propolypeptide did not bind to matrix of human foreskin fibroblasts. Since the propolypeptide does not associate with vWf and does not interact witji extracellular matrices in vitro, it is highly unlikely that it would promote platelet adhesion to subendothelium in vivo.

scholarly journals Unwinding the von Willebrand factor strings puzzle

Blood ◽  
2013 ◽  
Vol 121 (2) ◽  
pp. 270-277 ◽  
Author(s):  
Karen De Ceunynck ◽  
Simon F. De Meyer ◽  
Karen Vanhoorelbeke
Keyword(s):  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Cleavage Sites ◽  
Normal Functional ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract von Willebrand factor (VWF) is amongst others synthesized by endothelial cells and stored as ultra-large (UL) VWF multimers in Weibel-Palade bodies. Although UL-VWF is proteolysed by ADAMTS13 (a disintegrin-like and metalloprotease domain with thrombospondin type-1 motif, number 13) on secretion from endothelial cells, in vitro experiments in the absence of ADAMTS13 have demonstrated that a proportion of these UL-VWF multimers remain anchored to the activated endothelium. These multimers unravel, bind platelets, and wave in the direction of the flow. These so-called VWF “strings” have also been visualized in vivo, lining the lumen of activated mesenteric veins of Adamts13−/− mice. Various studies have demonstrated the extraordinary length of these VWF strings, the availability of their platelet binding and ADAMTS13 cleavage sites, and the possible nature of their endothelial attachment. VWF strings are also capable of tethering leukocytes and parasite-infected red blood cells. However, the majority of studies have been performed in the absence of ADAMTS13, a condition only experienced in thrombotic thrombocytopenic purpura. A normal functional role of VWF strings in healthy persons or in other disease pathologies remains unclear. In this review, we discuss some of the puzzling characteristics of VWF strings, and we debate whether the properties of VWF strings in the absence of ADAMTS13 might be relevant for understanding (patho)physiologic mechanisms.

scholarly journals EPAC regulates von Willebrand factor secretion from endothelial cells in a PI3K/eNOS-dependent manner during inflammation

2020 ◽  
Author(s):  
Jie Xiao ◽  
Ben Zhang ◽  
Zhengchen Su ◽  
Yakun Liu ◽  
Thomas R. Shelite ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Umbilical Vein ◽  
Null Mouse ◽  
Intracellular Camp ◽  
Dependent Manner ◽  
Von Willebrand ◽  
Willebrand Factor

AbstractCoagulopathy is associated with both inflammation and infection, including infection with the novel SARS-CoV-2 (COVID-19). Endothelial cells (ECs) fine tune hemostasis via cAMP-mediated secretion of von Willebrand factor (vWF), which promote the process of clot formation. The exchange protein directly activated by cAMP (EPAC) is a ubiquitously expressed intracellular cAMP receptor that plays a key role in stabilizing ECs and suppressing inflammation. To assess whether EPAC could regulate vWF release during inflammation, we utilized our EPAC1-null mouse model and revealed an increased secretion of vWF in endotoxemic mice in the absence of the EPAC1 gene. Pharmacological inhibition of EPAC1 in vitro mimicked the EPAC1−/− phenotype. EPAC1 regulated TNFα-triggered vWF secretion from human umbilical vein endothelial cells (HUVECs) in a phosphoinositide 3-kinases (PI3K)/endothelial nitric oxide synthase (eNOS)-dependent manner. Furthermore, EPAC1 activation reduced inflammation-triggered vWF release, both in vivo and in vitro. Our data delineate a novel regulatory role of EPAC1 in vWF secretion and shed light on potential development of new strategies to controlling thrombosis during inflammation.Key PointPI3K/eNOS pathway-mediated, inflammation-triggered vWF secretion is the target of the pharmacological manipulation of the cAMP-EPAC system.

scholarly journals Quantitative analysis of von Willebrand factor propeptide release in vivo: effect of experimental endotoxemia and administration of 1- deamino-8-D-arginine vasopressin in humans

Blood ◽  
1996 ◽  
Vol 88 (8) ◽  
pp. 2951-2958 ◽  
Author(s):  
A Borchiellini ◽  
K Fijnvandraat ◽  
JW ten Cate ◽  
D Pajkrt ◽  
SJ van Deventer ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Arginine Vasopressin ◽  
Molar Ratio ◽  
Cultured Endothelial Cells ◽  
Baseline Values ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Von Willebrand Factor Propeptide

The results of studies with cultured endothelial cells have shown that most von Willebrand factor (vWF) synthesized is directly secreted (constitutive pathway) and consists of both mature vWF, its precursor molecule pro-vWF, and the cleaved vWF prosequence. Only fully processed, functionally mature vWF is stored within the cell, together with the propeptide, and leaves the cell only on stimulation (regulated secretion). Both in resting and stimulated cultured endothelial cells, the stoichiometry of the released propeptide to the released mature vWF is essentially equimolar. In the present study, we have measured the molar ratio of propeptide to mature vWF in vivo, both under resting conditions and conditions that reflect activation of the endothelium. To this end, we devised a method that allows the measurement of the propeptide (vW antigen II) on a quantitative, is, molar basis, using purified recombinant propeptide as a standard. Our results show that the molar concentration of the propeptide in normal plasma is about one tenth of the concentration of mature vWF (expressed as half-dimer concentration). This ratio is approximately 1:1 in the medium of cultured endothelial cells. On administration in healthy subjects of either 1-deamino-8-D-arginine vasopressin or endotoxin, both agents being known to elicit an intravascular increase of vWF, the molar ratio of propeptide to mature vWF increased fourfold to fivefold. The propeptide concentration returned to baseline values after about 6 to 7 hours of injection of each stimulus, whereas the increase of mature vWF was much more sustained. Because the respective half-lives of mature vWF and its propeptide clearly differ, measurement of the concentration of these proteins could provide a means to assess the extent of activation of the endothelium under physiological and pathophysiological conditions.

scholarly journals Chronic hypoxia in vivo increases von Willebrand factor expression in lung endothelial cells

2008 ◽  
Vol 22 (S1) ◽  
Author(s):  
Alice Huertas ◽  
Steven Greenberg ◽  
Maimaiti Yiming ◽  
Jahar Bhattacharya ◽  
Sunita Bhattacharya
Keyword(s):  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Chronic Hypoxia ◽  
Factor Expression ◽  
Lung Endothelial Cells ◽  
Von Willebrand ◽  
Willebrand Factor

The Effect of von Willebrand Factor (VWF) on Site-Specific Factor VIII (FVIII) Expression in Hemophilia A Mice.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 764-764
Author(s):  
Qizhen Shi ◽  
Scot A. Fahs ◽  
Erin L. Kuether ◽  
Robert R. Montgomery
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Factor Viii ◽  
Von Willebrand Factor ◽  
Double Knockout ◽  
Site Specific ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract von Willebrand factor (VWF) is a carrier protein for factor VIII (FVIII) and protects plasma FVIII from protease degradation. Our laboratory has had a longstanding interest in the association of FVIII with VWF both in vitro and in vivo. Our in vitro studies have demonstrated that FVIII stores together with VWF in both endothelial cells and megakaryocytes if FVIII is made in these cells. Furthermore, we demonstrated that FVIII and VWF are both releasable by agonist stimulation. To investigate the association of VWF and FVIII in vivo, we generated two lines of transgenic mice that express FVIII either in endothelial cells or in platelets using either the endothelial cell-specific Tie2 promoter or the platelet-specific αIIb promoter, respectively. When the platelet-specific FVIII (2bF8) transgene is bred into the FVIIInull mouse, FVIII can only be detected in platelets, with a level of 0.76 ± 0.27 mU/108 platelets in heterozygous and 1.53 ± 0.14 mU/108 platelets in homozygous 2bF8 mice. When the endothelial cell-specific FVIII (Tie2F8) transgene is bred into the FVIIInull mouse, homozygous Tie2F8 mice maintained normal plasma FVIII levels (1.15 ± 0.16 U/ml) and 50% levels in heterozygous mice (0.56 ± 0.16 U/ml). Both 2bF8trans and Tie2F8trans phenotypes effectively abrogate the bleeding diathesis in hemophilic mice. When 2bF8 transgene was bred into a FVIII and VWF double knockout background, the level of platelet-FVIII significantly decreased, but this platelet-derived FVIII was still stored in a-granules and still maintained clinical efficacy. In contrast, when the Tie2F8 transgene was bred into the double knockout background, plasma FVIII dropped to undetectable levels. This is in contrast to the situation in VWFnull mice in which normal endogenous murine FVIII is synthesized with about 10% of normal FVIII activity persisting in plasma. This could be due to a difference in survival between human FVIII and murine FVIII. All Tie2F8trans/FVIIInullVWFnull mice (n=15) survived tail clipping even though there is no FVIII:C detected in the plasma. To investigate the effect of murine VWF on the levels of plasma FVIII, plasma from FVIIInull mice was infused into Tie2F8trans/FVIIInullVWFnull mice to restore VWF levels to 25% of normal. As expected, the endothelial cell-derived plasma FVIII was stabilized by the infused VWF and was detected within 1 hour after infusion, with a peak (25% level) at 4 hours. The level of plasma FVIII at 24 hours was still about 20% of normal while the level of remaining VWF was only 5% of normal. These results demonstrate that VWF is important for site-specific FVIII expression. Co-expression with VWF in platelets is important for optimal platelet-specific FVIII expression and endothelial cell-derived plasma FVIII is VWF-dependent.

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