The NFY Transcription Factor Mediates Induction of the von Willebrand Factor Promoter by Irradiation

2001 ◽  
Vol 85 (05) ◽  
pp. 837-844 ◽  
Author(s):  
Angela Bertagna ◽  
Nadia Jahroudi

SummaryIonizing irradiation in patients is proposed to cause thrombus formation. An increase in von Willebrand factor secretion in response to irradiation is a major contributing factor to thrombus formation. We have previously reported that the increased VWF secretion in response to irradiation is mediated at the transcriptional level. The VWF core promoter fragment (sequences –90 to +22) was shown to contain the necessary cis-acting element(s) to mediate the irradiation response of the VWF gene. Here we report that a CCAAT element in the VWF promoter is the cis-acting element necessary for irradiation induction and that the NFY transcription factor interacts with this element. These analyses demonstrate that inhibition of NFY’s interaction with the CCAAT element abolishes the irradiation induction of the VWF promoter. These results provide a novel role for NFY and add this factor to the small list of irradiation-responsive transcription factors. Coimmunoprecipitation experiments demonstrated that NFY is associated with the histone acetylase P/CAF in vivo and that irradiation resulted in an increased association of NFY with coactivator P/CAF. We propose that irradiation induction of the VWF promoter involves a mechanism resulting in increased recruitment of the coactivator P/CAF to the promoter via the NFY transcription factor.

2020 ◽  
Vol 120 (03) ◽  
pp. 466-476
Author(s):  
Sibgha Tahir ◽  
Andreas H. Wagner ◽  
Steffen Dietzel ◽  
Hanna Mannell ◽  
Joachim Pircher ◽  
...  

Abstract Background von Willebrand factor (vWF) plays an important role in platelet activation. CD40–CD40 ligand (CD40L) induced vWF release has been described in large vessels and cultured endothelium, but its role in the microcirculation is not known. Here, we studied whether CD40 is expressed in murine microvessels in vivo, whether CD40L induces platelet adhesion and leukocyte activation, and how deficiency of the vWF cleaving enzyme ADAMTS13 affects these processes. Methods and Results The role of CD40L in the formation of beaded platelet strings reflecting their adhesion to ultralarge vWF fibers (ULVWF) was analyzed in the murine cremaster microcirculation in vivo. Expression of CD40 and vWF was studied by immunohistochemistry in isolated and fixed cremasters. Microvascular CD40 was only expressed under inflammatory conditions and exclusively in venous endothelium. We demonstrate that CD40L treatment augmented the number of platelet strings, reflecting ULVWF multimer formation exclusively in venules and small veins. In ADAMTS13 knockout mice, the number of platelet strings further increased to a significant extent. As a consequence extensive thrombus formation was induced in venules of ADAMTS13 knockout mice. In addition, circulating leukocytes showed primary and rapid adherence to these platelet strings followed by preferential extravasation in these areas. Conclusion CD40L is an important stimulus of microvascular endothelial ULVWF release, subsequent platelet string formation and leukocyte extravasation but only in venous vessels under inflammatory conditions. Here, the lack of ADAMTS13 leads to severe thrombus formation. The results identify CD40 expression and ADAMTS13 activity as important targets to prevent microvascular inflammatory thrombosis.


2000 ◽  
Vol 84 (09) ◽  
pp. 381-387 ◽  
Author(s):  
Nailin Li ◽  
Anne Soop ◽  
Alf Sollevi ◽  
Paul Hjemdahl

SummaryThe influence of adenosine infusion (40 µg/kg/min for 4 h) on inflammatory and hemostatic parameters was investigated in healthy males without (n = 10) or with (n = 11) intravenous endotoxin injection (4 ng/kg). Without endotoxin, adenosine elevated circulating leukocytes and circulating platelet-leukocyte aggregates. Endotoxin activated platelets and leukocytes in vivo. Platelet activation was seen as slightly increased platelet P-selectin expression, decreased platelet counts, and elevated plasma soluble P-selectin (from 39.6 ± 3.4 to 68.9 ± 6.6 ng/ml; P <0.01). Leukocyte activation was evidenced by increased CD11b expression (from MFI of 0.54 ± 0.02 to 2.21 ± 0.17; P <0.01) and plasma elastase levels (from 25.3 ± 2.5 to 169.3 ± 22.5 ng/ml; P <0.01). Endotoxin also enhanced platelet and leukocyte responsiveness to in vitro stimulation. Endotoxin induced von Willebrand factor secretion (from 92 ± 8 units to 265 ± 19 units at 4 h; P <0.001) and enhanced thrombin generation in vivo. Endotoxin induced leukocytosis and thus increased circulating platelet-leukocyte, mainly platelet-neutrophil, aggregates. Adenosine caused slight attenuation of platelet reactivity to agonist stimulation, enhanced the endotoxin-induced leukocytosis, and detained more platelet-leukocyte aggregates in circulation, but did not attenuate endotoxin-induced neutrophil elastase secretion, von Willebrand factor secretion, or thrombin generation. Thus, endotoxemia induces multi-cellular activation in vivo. Adenosine inhibits leukocyte adhesion and extravasation, and mildly attenuates platelet responsiveness and soluble P-selectin release. Adenosine has the potential of becoming a therapeutic antiinflammatory drug, but an optimal treatment strategy needs to be developed.


FEBS Journal ◽  
2009 ◽  
Vol 277 (2) ◽  
pp. 413-427 ◽  
Author(s):  
Eric Calvo ◽  
Fuyuki Tokumasu ◽  
Daniella M. Mizurini ◽  
Peter McPhie ◽  
David L. Narum ◽  
...  

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1797-1797 ◽  
Author(s):  
Wolfgang Bergmeier ◽  
Crystal L. Piffath ◽  
Tobias Goerge ◽  
Stephen M. Cifuni ◽  
Zaverio M. Ruggeri ◽  
...  

Abstract GPIbα binding to von Willebrand factor (VWF) exposed at a site of vascular injury is thought to be the first step in the formation of a hemostatic plug. However, our previous studies in VWF-deficient mice demonstrated delayed but not absent arterial thrombus formation suggesting that, under these conditions, GPIbα may bind other ligands or that a receptor other than GPIbα can mediate platelet adhesion. Here we studied thrombus formation in transgenic mice expressing GPIbα in which the extracellular domain was replaced by that of the human interleukin-4 receptor (IL4Rα/GPIbα-tg mice). Platelet adhesion to ferric chloride-treated mesenteric arterioles in IL4Rα/GPIbα-tg mice was virtually absent in contrast to avid adhesion in wild-type (WT) mice. As a consequence, arterial thrombus formation was completely inhibited in the mutant mice. Our studies further show that, when infused into WT recipient mice, IL4Rα/GPIbα-tg platelets or WT platelets lacking the 45 kD N-terminal domain of GPIbα failed to incorporate into growing arterial thrombi, even if the platelets were activated prior to infusion. Surprisingly, platelets lacking β3 integrins, which are unable to form thrombi on their own, incorporated efficiently into WT thrombi. Our studies provide in vivo evidence that GPIbα is absolutely required for recruitment of platelets to both exposed subendothelium and thrombi under arterial flow conditions. Thus, GPIbα contributes to arterial thrombosis by important adhesion mechanisms independent of the binding to VWF.


Blood ◽  
2009 ◽  
Vol 114 (27) ◽  
pp. 5541-5546 ◽  
Author(s):  
Jose A. Guerrero ◽  
Mark Kyei ◽  
Susan Russell ◽  
Junling Liu ◽  
T. Kent Gartner ◽  
...  

AbstractPlatelet-type von Willebrand disease (PT-VWD) is a bleeding disorder of the platelet glycoprotein Ib-IX/von Willebrand factor (VWF) axis caused by mutations in the glycoprotein Ib-IX receptor that lead to an increased affinity with VWF. In this report, platelets from a mouse expressing a mutation associated with PT-VWD have been visualized using state-of-the art image collection and processing. Confocal analysis revealed that VWF bound to the surface of single platelets and bridging micro-aggregates of platelets. Surface-bound VWF appears as a large, linear structure on the surface of 50% of the PT-VWD platelets. In vivo thrombus formation after chemical injury to the carotid artery revealed a severe impairment to occlusion as a consequence of the PT-VWD mutation. In vitro stimulation of PT-VWD platelets with adenosine diphosphate or thrombin demonstrates a significant block in their ability to bind fibrinogen. The impairment of in vivo thrombus formation and in vitro fibrinogen binding are more significant than might be expected from the observed platelet binding to VWF polymers over a small portion of the plasma membrane. Visualization of the receptor/ligand interaction and characterization of a severe antithrombotic phenotype provide a new understanding on the molecular basis of bleeding associated with the PT-VWD phenotype.


Blood ◽  
1997 ◽  
Vol 90 (11) ◽  
pp. 4413-4424 ◽  
Author(s):  
Masaaki Moroi ◽  
Stephanie M. Jung ◽  
Shosaku Nomura ◽  
Sadayoshi Sekiguchi ◽  
Antonio Ordinas ◽  
...  

The requisite initial reaction for in vivo thrombus formation in flowing blood is platelet adhesion to the exposed surface of the extracellular matrix. The contribution of von Willebrand factor (vWF ) in plasma and glycoprotein (GP) Ib on the platelet membrane to platelet adhesion has been well-documented. We have recently developed a procedure (the “flow adhesion assay”) for measuring platelet adhesion under flow conditions that allowed us to characterize platelet adhesion to a collagen-coated surface. Here, we apply our method to analyze platelet adhesion to a vWF-coated surface to determine how this might differ from adhesion to a collagen-coated surface. Platelet adhesion to the vWF-coated surface was monitored as the linear increase in the area occupied by adherent platelets. The fluorescence image showed that platelets adhering to the vWF surface were mainly single platelets, and if any were present, the platelet aggregates were small, this being the primary difference from the adhesion to a collagen surface, where adherent platelets were mostly in aggregates. The flow adhesion assay detected the movement of platelets on the vWF surface, suggesting the reversible binding of vWF with platelets. The velocity of the platelets increased at higher shear rates or at lower vWF densities on the surface. Treatment of the vWF-coated surface with the aggregating agent botrocetin before initiation of blood flow increased platelet adhesion while dramatically decreasing the velocity of platelet movement. The present observations on the adhesion of platelets to the vWF-pretreated collagen surface and measurements of the velocity of platelets moving on the collagen surface suggest that the first interaction on the collagen-coated surface is the binding of vWF molecules to the collagen surface. This small number of vWF molecules would serve to attract and slow platelets flowing near the surface. This would facilitate the actual adhesion to the collagen surface that is mainly generated by the interaction between platelet collagen receptors, including GP Ia/IIa and GP VI, with collagen.


Blood ◽  
1997 ◽  
Vol 90 (11) ◽  
pp. 4413-4424 ◽  
Author(s):  
Masaaki Moroi ◽  
Stephanie M. Jung ◽  
Shosaku Nomura ◽  
Sadayoshi Sekiguchi ◽  
Antonio Ordinas ◽  
...  

Abstract The requisite initial reaction for in vivo thrombus formation in flowing blood is platelet adhesion to the exposed surface of the extracellular matrix. The contribution of von Willebrand factor (vWF ) in plasma and glycoprotein (GP) Ib on the platelet membrane to platelet adhesion has been well-documented. We have recently developed a procedure (the “flow adhesion assay”) for measuring platelet adhesion under flow conditions that allowed us to characterize platelet adhesion to a collagen-coated surface. Here, we apply our method to analyze platelet adhesion to a vWF-coated surface to determine how this might differ from adhesion to a collagen-coated surface. Platelet adhesion to the vWF-coated surface was monitored as the linear increase in the area occupied by adherent platelets. The fluorescence image showed that platelets adhering to the vWF surface were mainly single platelets, and if any were present, the platelet aggregates were small, this being the primary difference from the adhesion to a collagen surface, where adherent platelets were mostly in aggregates. The flow adhesion assay detected the movement of platelets on the vWF surface, suggesting the reversible binding of vWF with platelets. The velocity of the platelets increased at higher shear rates or at lower vWF densities on the surface. Treatment of the vWF-coated surface with the aggregating agent botrocetin before initiation of blood flow increased platelet adhesion while dramatically decreasing the velocity of platelet movement. The present observations on the adhesion of platelets to the vWF-pretreated collagen surface and measurements of the velocity of platelets moving on the collagen surface suggest that the first interaction on the collagen-coated surface is the binding of vWF molecules to the collagen surface. This small number of vWF molecules would serve to attract and slow platelets flowing near the surface. This would facilitate the actual adhesion to the collagen surface that is mainly generated by the interaction between platelet collagen receptors, including GP Ia/IIa and GP VI, with collagen.


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