Adhesion of human and mouse platelets to collagen under shear: a unifying model

Auger, Jocelyn M.; Kuijpers, Marijke J. E.; Senis, Yotis A.; Watson, Steve P.; Heemskerk, Johan W. M.

doi:10.1096/fj.04-1940fje

Cited by 116 publications

(125 citation statements)

References 38 publications

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“…After perfusion, platelets from FcR ␥-chain null mice and also wild-type platelets treated with PD173952 failed to bind fibrinogen ( Figure I), pointing to the requirement of the FcR ␥-chain and Src kinases to the aggregate-forming process. 17 Together, these results indicate that the signaling components of the GPVI-PLC␥2 pathway (involving Src kinases, FcR␥, Syk, and LAT) are indispensable for PS exposure on collagen under flow. The PS-exposing platelets typically represent a different population than the platelets assembled into aggregates and binding fibrinogen.…”

mentioning

confidence: 77%

“…It essentially abolishes all collagen-induced but not thrombin-induced tyrosine phosphorylation events in platelets. 17 Furthermore, mice deficient in LAT 18 or PLC␥2 19 were used to study the contribution of these downstream signaling entities.In the first experiments, PPACK-anticoagulated whole blood from wild-type or genetically modified mice was perfused over a collagen surface at a shear rate of 1000 s Ϫ1 , which is representative of that found in murine arterioles. Using wild-type blood, platelets rapidly adhered to the collagen surface and partly assembled into aggregates.…”

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confidence: 99%

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The Glycoprotein VI-Phospholipase Cγ2 Signaling Pathway Controls Thrombus Formation Induced by Collagen and Tissue Factor In Vitro and In Vivo

Munnix

Strehl

Kuijpers

et al. 2005

ATVB

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Objective-Both collagen and tissue factor can be initiating factors in thrombus formation. We investigated the signaling pathway of collagen-induced platelet activation in interaction with tissue factor-triggered coagulation during the thrombus-forming process. Methods and Results-In murine blood flowing over collagen, platelet exposure of phosphatidylserine and procoagulant activity, but not adhesion, completely relied on each of the following signaling modules: glycoprotein VI (GPVI), FcR ␥-chain, Src kinases, adaptor protein LAT, and phospholipase C␥2 (PLC␥2). On flow in the presence of tissue factor, these signaling components were essential for platelet aggregation and greatly enhanced fibrin clot formation. Collagen-stimulated thrombin generation relied on the presence and activity of GPVI, FcR ␥-chain, Src kinase, LAT, and PLC␥2. The physiological importance of this GPVI pathway was shown in a FeCl 3 -induced in vivo murine thrombosis model. In both venules and arterioles, signaling through GPVI, FcR ␥-chain, and Src kinases enhanced the formation of phosphatidylserine-exposing and fibrin-rich thrombi. Key Words: glycoprotein VI Ⅲ LAT Ⅲ platelets Ⅲ Src kinase Ⅲ thrombin T hrombus formation can be initiated by both platelet-and coagulation-activating factors. Collagens in the extracellular matrix and other vascular layers are thought to act as principal platelet-activating components of the damaged vessel wall; they also provide a surface for von Willebrand factor adhesion. 1 Tissue factor, also exposed in damaged vessels, is a key trigger of the coagulation process. 2 Because of the proposed major role of platelets in arterial thrombosis and the importance of coagulation in venous thrombosis, the current understanding is that collagen/von Willebrand factor-mediated events are more important in arteries, whereas tissue factor plays a more prominent role in venous thrombus formation. Conclusions-TheFlow studies with human and mouse blood have established that the signaling receptor glycoprotein VI (GPVI) exclusively mediates collagen-induced platelet procoagulant activity, thus linking the processes of platelet activation and coagulation. [3][4][5] This procoagulant platelet response is mediated by a prolonged and potent rise in cytosolic [Ca 2ϩ ] i , which results in exposure of procoagulant phosphatidylserine (PS) at the platelet outer surface. 6 PS exposure is a key regulating factor in the coagulation process. For instance, PS-containing membrane surfaces dramatically increase the formation of factor Xa and thrombin. 7 However, several authors have argued that this platelet response has only an assistant role in coagulation and that, in vivo, other platelet reactions may play important roles as well. 2,8 Thus, although there is no doubt that platelets enhance thrombin generation (coagulation) in plasma or whole blood, the precise mechanism is still a matter of debate. The platelet immunoreceptor GPVI is coexpressed with the Fc receptor (FcR) ␥-chain, although the latter also interacts with other plat...

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confidence: 77%

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confidence: 99%

The Glycoprotein VI-Phospholipase Cγ2 Signaling Pathway Controls Thrombus Formation Induced by Collagen and Tissue Factor In Vitro and In Vivo

Munnix

Strehl

Kuijpers

et al. 2005

ATVB

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Section: Discussionmentioning

confidence: 99%

“…There has been much debate regarding the roles of ␣ 2 ␤ 1 integrin and GPVI/FcR␥ complex in the two-step, two-site model (44,45). It has been suggested that engagement of GPVI may be required for activation of the ␣ 2 ␤ 1 integrin (29,44,45). We have previously shown that platelets from ␣ 2 ␤ 1 -deficient mice have delayed thrombus formation in vivo within the carotid artery (12), and that under flow conditions in vitro, GPVI/FcR␥ complex and ␣ 2 ␤ 1 integrin both play independent and vital roles in platelet adhesion and aggregation to collagen (46).…”

Section: Discussionmentioning

confidence: 99%

Suboptimal Activation of Protease-activated Receptors Enhances α2β1 Integrin-mediated Platelet Adhesion to Collagen

Marjoram

Voss

Pan

et al. 2009

Journal of Biological Chemistry

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Thrombin and fibrillar collagen are potent activators of platelets at sites of vascular injury. Both agonists cause platelet shape change, granule secretion, and aggregation to form the primary hemostatic plug. Human platelets express two thrombin receptors, protease-activated receptors 1 and 4 (PAR1 and PAR4) and two collagen receptors, the ␣ 2 ␤ 1 integrin (␣ 2 ␤ 1 ) and the glycoprotein VI (GPVI)/FcR␥ chain complex. Although these receptors and their signaling mechanisms have been intensely studied, it is not known whether and how these receptors cooperate in the hemostatic function of platelets. This study examined cooperation between the thrombin and collagen receptors in platelet adhesion by utilizing a collagen-related peptide (␣2-CRP) containing the ␣ 2 ␤ 1 -specific binding motif, GFOGER, in conjunction with PAR-activating peptides. We demonstrate that platelet adhesion to ␣2-CRP is substantially enhanced by suboptimal PAR activation (agonist concentrations that do not stimulate platelet aggregation) using the PAR4 agonist peptide and thrombin. The enhanced adhesion induced by suboptimal PAR4 activation was ␣ 2 ␤ 1 -dependent and GPVI/FcR␥-independent as revealed in experiments with ␣ 2 ␤ 1 -or FcR␥-deficient mouse platelets. We further show that suboptimal activation of other platelet G q -linked G protein-coupled receptors (GPCRs) produces enhanced platelet adhesion to ␣2-CRP. The enhanced ␣ 2 ␤ 1 -mediated platelet adhesion is controlled by phospholipase C (PLC), but is not dependent on granule secretion, activation of ␣ IIb ␤ 3 integrin, or on phosphoinositol-3 kinase (PI3K) activity. In conclusion, we demonstrate a platelet priming mechanism initiated by suboptimal activation of PAR4 or other platelet G q -linked GPCRs through a PLC-dependent signaling cascade that promotes enhanced ␣ 2 ␤ 1 binding to collagens containing GFOGER sites.Platelets are small anuclear cellular elements that play a central role in hemostasis and contribute to vascular pathology. At sites of intravascular injury, platelets are exposed to multiple prothrombotic factors that promote thrombus formation and trigger firm adhesion of platelets to the subendothelial extracellular matrix. Thrombin and fibrillar collagen are two of the more potent stimuli (1, 2).Thrombin is an essential serine protease in the coagulation cascade that ultimately converts fibrinogen to fibrin. Thrombin also has a direct signaling effect on cells through protease-activated receptors (PARs) 2 , which are G protein-coupled receptors (GPCRs) that are activated by enzymatic cleavage of the N terminus of the receptor to produce a tethered ligand (3). Of the four known PAR isoforms, human platelets express PAR1 and PAR4. In platelets, these receptors show different signaling kinetics; PAR1 is activated at low thrombin concentrations with a quick signal shutoff, whereas, PAR4 is activated at higher thrombin concentrations with a slow signal shut off (4 -6). Thrombin-induced signaling has been shown to modulate ligand affinity of the platelet membrane ␣ IIb ...

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“…The first step in platelet recruitment to collagen occurs indirectly via binding of platelet glycoprotein (GP) 2 Ib to collagen-bound von Willebrand factor (vWf), which plays a critical role in tethering of platelets at high shear levels (26,27). The rapid off-rate of GPIb-vWf interactions results in platelet translocation at the site of injury, allowing adhesive interactions with slower binding kinetics, such as the platelet collagen receptors glycoprotein VI and ␣ 2 ␤ 1 integrins, to mediate platelet adhesion and activation (23)(24)(25)(26)(27)(28). The relative contributions of these two receptors to collagen-mediated platelet responses are under intense investigation (28 -34), and different models have been proposed in an attempt to explain how platelets are activated by collagen (23,28,35).…”

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confidence: 99%

Aegyptin, a Novel Mosquito Salivary Gland Protein, Specifically Binds to Collagen and Prevents Its Interaction with Platelet Glycoprotein VI, Integrin α2β1, and von Willebrand Factor

Calvo

Tokumasu

Marinotti

et al. 2007

Journal of Biological Chemistry

100

111

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Blood-sucking arthropods have evolved a number of inhibitors of platelet aggregation and blood coagulation. In this study we have molecularly and functionally characterized aegyptin, a member of the family of 30-kDa salivary allergens from Aedes aegypti, whose function remained elusive thus far. Aegyptin displays a unique sequence characterized by glycine, glutamic acid, and aspartic acid repeats and was shown to specifically block collagen-induced human platelet aggregation and granule secretion. Plasmon resonance experiments demonstrate that aegyptin binds to collagen types I-V (K d ≈ 1 nM) but does not interact with vitronectin, fibronectin, laminin, fibrinogen, and von Willebrand factor (vWf). In addition, aegyptin attenuates platelet adhesion to soluble or fibrillar collagen. Furthermore, aegyptin inhibits vWf interaction with collagen type III under static conditions and completely blocks platelet adhesion to collagen under flow conditions at high shear rates. Notably, aegyptin prevents collagen but not convulxin binding to recombinant glycoprotein VI. These findings suggest that aegyptin recognizes specific binding sites for glycoprotein VI, integrin ␣2␤1, and vWf, thereby preventing collagen interaction with its three major ligands. Aegyptin is a novel tool to study collagen-platelet interaction and a prototype for development of molecules with antithrombotic properties.

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Adhesion of human and mouse platelets to collagen under shear: a unifying model

Cited by 116 publications

References 38 publications

The Glycoprotein VI-Phospholipase Cγ2 Signaling Pathway Controls Thrombus Formation Induced by Collagen and Tissue Factor In Vitro and In Vivo

The Glycoprotein VI-Phospholipase Cγ2 Signaling Pathway Controls Thrombus Formation Induced by Collagen and Tissue Factor In Vitro and In Vivo

Suboptimal Activation of Protease-activated Receptors Enhances α2β1 Integrin-mediated Platelet Adhesion to Collagen

Aegyptin, a Novel Mosquito Salivary Gland Protein, Specifically Binds to Collagen and Prevents Its Interaction with Platelet Glycoprotein VI, Integrin α2β1, and von Willebrand Factor

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