Platelet glycoprotein V binds to collagen and participates in platelet adhesion and aggregation

Blood ◽  
2001 ◽  
Vol 98 (4) ◽  
pp. 1038-1046 ◽  
Author(s):  
Sylvie Moog ◽  
Pierre Mangin ◽  
Nadège Lenain ◽  
Catherine Strassel ◽  
Catherine Ravanat ◽  
...  

Glycoprotein V (GPV) is a subunit of the platelet GPIb-V-IX receptor for von Willebrand factor and thrombin. GPV is cleaved from the platelet surface during activation by thrombin, but its role in hemostasis is still unknown. It is reported that GPV knockout mice had a decreased tendency to form arterial occluding thrombi in an intravital thrombosis model and abnormal platelet interaction with the subendothelium. In vitro, GPV-deficient platelets exhibited defective adhesion to a collagen type I–coated surface under flow or static conditions. Aggregation studies demonstrated a decreased response of the GPV-deficient platelets to collagen, reflected by an increased lag phase and reduced amplitude of aggregation. Responses to adenosine diphosphate, arachidonic acid, and the thromboxane analog U46619 were normal but were enhanced to low thrombin concentrations. The defect of GPV null platelets made them more sensitive to inhibition by the anti-GPVI monoclonal antibody (mAb) JAQ1, and this was also the case in aspirin- or apyrase-treated platelets. Moreover, an mAb (V.3) against the extracellular domain of human GPV selectively inhibited collagen-induced aggregation in human or rat platelets. V.3 injected in rats as a bolus decreased the ex vivo collagen aggregation response without affecting the platelet count. Finally, surface plasmon resonance studies demonstrated binding of recombinant soluble GPV on a collagen-coupled matrix. In conclusion, GPV binds to collagen and appears to be required for normal platelet responses to this agonist.

1981 ◽  
Author(s):  
D G Moon ◽  
J E Kaplan

Platelets contain fibronectin a glycoprotein with an established affinity for collagen. This observation has led other investigators to postulate that fibronectin is the platelet collagen receptor. The much greater concentration of fibronectin in the plasma surrounding platelets, however, has led us to suggest that plasma fibronectin may bind to collagen and competitively inhibit the platelet- collagen interaction. Rat platelets were isolated by Stractan density gradient centrifugation and aggregated with acid-solubilized rat tail tendon collagen (Type I) in a Payton 300B Aggregometer. Fibronectin was twice purified by affinity chromatography with gelatin linked to CNBr- activated Sepharose 4B. Simultaneous addition of 50 μg fibronectin and 25 μg collagen to platelets suspended in Tyrodes solution at 37°C resulted in a 2-fold increase in lag time and a 30% decrease in aggregation rate as compared to control values. When collagen was preincubated in Tyrodes solution for 12 minutes at 26°C without platelets to allow for prior fibrillogenesis, the addition of 50 μg fibronectin with the platelets resulted in <20% increase in lag time and a 20-30% decrease in aggregation rate. In a separate series of experiments, fibronectin was also found to inhibit ADP-induced aggregation. In this case, the initial rate of aggregation was comparable with and without fibronectin, but this maximal rate was maintained for a shorter period in the presence of fibronectin. Thus, fibronectin reduced the in vitro aggregation response to two different physiological stimuli. Our data supports previous studies which indicate that fibronectin reduces the reactivity of platelets with collagen and provides evidence of a role for fibronectin in modulating platelet responses in the absence of collagen.


1981 ◽  
Author(s):  
C Ruan ◽  
G Tobelem ◽  
A McMichael ◽  
L Drouet ◽  
Y Legrand ◽  
...  

A monoclonal antibody (AN51) to human platelet glycoprotein I (GPI) secreted by a hybrid myeloma has been tested on platelet functions. AN51 bound to normal and thrombasthenic platelets while it failed to bind to platelets from 6 patients with Bernard-Soulier syndrome (BSS). The nature of the antigen recognized by AN51 was determined by demonstration that the antigen, which was chymotrypsin sensitive, gave a peak at 150,000 daltons on SDS-PAGE after immunoprecipitation. AN51 strongly inhibited Ristocetin, bovine factor VIII or porcine factor VIII induced aggregation but did not modify ADP, collagen type I or type III, thrombin or arachidonic acid induced aggregations. Furthermore the adhesion-aggregation of platelet induced by microfibrils was also inhibited by the antibody AN51. Platelet adhesion to untreated or collagenase treated rabbit aorta subendothelium, using the Baumgartner technique, was impaired by AN51, and the inhibition was more pronouced at high shear rate conditions. AN51 decreased the binding of 125I-factor VIII/Willebrand factor (FVIII/WF) to human platelets in presence of Ristocetin. The use of this monoclonal antibody directed against platelet GPI permits a better understanding of the platelet-platelet and platelet-subendothelium interactions mediated by FVIII/WF and will facilitate the purification of the platelet membrane glycoprotein lacking in BSS which may be the receptor for FVIII/WF.


Sci ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 30
Author(s):  
Agnė Žiniauskaitė ◽  
Vytautas Cėpla ◽  
Tadas Jelinskas ◽  
Romuald Eimont ◽  
Artūras Ulčinas ◽  
...  

There is a growing need for novel in vitro corneal models to replace animal-based ex vivo tests in drug permeability studies. In this study, we demonstrated a corneal mimetic that models the stromal and epithelial compartments of the human cornea. Human corneal epithelial cells (HCE-T) were grown on top of a self-supporting porcine collagen-based hydrogel. Cross-sections of the multi-layers were characterized by histological staining and immunocytochemistry of zonula oc-cludens-1 protein (ZO-1) and occludin. Furthermore, water content and bssic elastic properties of the synthetized collagen type I-based hydrogels were measured. The apparent permeability coefficient (Papp) values of a representative set of ophthalmic drugs were measured and correlated to rabbit cornea Papp values found in the literature. A multilayered structure of HCE-T cells and the expression of ZO-1 and occludin in the full thickness of the multilayer were observed. The hydrogel-based corneal model exhibited an excellent correlation to rabbit corneal permeability (r = 0.96), whereas the insert-grown HCE-T multilayer was more permeable and the correlation to the rabbit corneal permeability was lower (r = 0.89). The hydrogel-based human corneal model predicts the rabbit corneal permeability more reliably in comparison to HCE-T cells grown in inserts. This in vitro human corneal model can be successfully employed for drug permeability tests whilst avoiding ethical issues and reducing costs.


Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3218-3224 ◽  
Author(s):  
Y Cadroy ◽  
SR Hanson ◽  
AB Kelly ◽  
UM Marzec ◽  
BL Evatt ◽  
...  

Abstract The relative antithrombotic effectiveness of targeting glycoprotein (GP) Ib-dependent versus GPIIb-IIIa-dependent platelet interactions has been determined in baboons by measuring thrombus formation after infusing comparable antihemostatic doses of anti-von Willebrand factor (vWF) monoclonal antibody (MoAb) BB3-BD5, anti-GPIb MoAb AP1, and anti- GPIIb-IIIa MoAb LJ-CP8 under conditions of arterial and venous flow (shear rates of 750 to 1,000 seconds-1 and 100 seconds-1, respectively). Thrombus formation was quantified as 111In-platelet deposition and 125I-fibrin accumulation on segments of collagen-coated tubing interposed in chronic exteriorized arteriovenous (AV) shunts for 40 minutes. In vitro, anti-vWF MoAb BB3 BD5 (IgG) and anti-GPIb MoAb AP1 [IgG or F(ab)2 fragments] inhibited ristocetin-induced platelet aggregation (IC50 50 nmol/L and 1 mumol/L, respectively), but neither of these MoAbs blocked platelet aggregation induced by adenosine diphosphate (ADP) (P > .5). Conversely, anti-GPIIb-IIIa MoAb LJ-CP8 inhibited platelet aggregation induced by ADP (IC50 1 mumol/L, but failed to block ristocetin-induced platelet aggregation (P > .5). In vivo, the intravenous infusion of anti-vWF MoAb BB3 BD5 or anti-GPIIb- IIIa MoAb LJ-CP8 into baboons at doses that abolished corresponding agonist-induced aggregation ex vivo (bolus injections of 0.5 mg/kg and 10 mg/kg, respectively) prolonged template bleeding times from baseline values of 4.0 +/- 0.3 minutes to > 27 +/- 4 minutes, and to > 26 +/- 4 minutes, respectively (P 3 .001 in both cases), without affecting the peripheral platelet count (P > .5). However, injection of anti-GPIb MoAb AP1 [10 mg/kg as IgG or 1 mg/kg as F(ab)2 fragments] produced immediate irreversible thrombocytopenia (< 40,000 platelets/microL). Anti-GPIIb-IIIa MoAb LJ-CP8 abolished platelet deposition and fibrin accumulation on collagen segments under both arterial and venous flow conditions (P < .01 in all cases), whereas MoAb BB3 BD5 produced minimal inhibition of platelet deposition and no decrease in fibrin accumulation at arterial shear rates and undetectable antithrombotic outcomes at low shear. Thus, inhibiting GPIIb-IIIa-dependent platelet recruitment abrogates both thrombus formation and platelet hemostatic function at both venous and arterial shear rates. By contrast, interfering with GPIb-vWF-dependent platelet interactions abolishes platelet hemostatic function without producing corresponding antithrombotic effects.


Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3218-3224 ◽  
Author(s):  
Y Cadroy ◽  
SR Hanson ◽  
AB Kelly ◽  
UM Marzec ◽  
BL Evatt ◽  
...  

The relative antithrombotic effectiveness of targeting glycoprotein (GP) Ib-dependent versus GPIIb-IIIa-dependent platelet interactions has been determined in baboons by measuring thrombus formation after infusing comparable antihemostatic doses of anti-von Willebrand factor (vWF) monoclonal antibody (MoAb) BB3-BD5, anti-GPIb MoAb AP1, and anti- GPIIb-IIIa MoAb LJ-CP8 under conditions of arterial and venous flow (shear rates of 750 to 1,000 seconds-1 and 100 seconds-1, respectively). Thrombus formation was quantified as 111In-platelet deposition and 125I-fibrin accumulation on segments of collagen-coated tubing interposed in chronic exteriorized arteriovenous (AV) shunts for 40 minutes. In vitro, anti-vWF MoAb BB3 BD5 (IgG) and anti-GPIb MoAb AP1 [IgG or F(ab)2 fragments] inhibited ristocetin-induced platelet aggregation (IC50 50 nmol/L and 1 mumol/L, respectively), but neither of these MoAbs blocked platelet aggregation induced by adenosine diphosphate (ADP) (P > .5). Conversely, anti-GPIIb-IIIa MoAb LJ-CP8 inhibited platelet aggregation induced by ADP (IC50 1 mumol/L, but failed to block ristocetin-induced platelet aggregation (P > .5). In vivo, the intravenous infusion of anti-vWF MoAb BB3 BD5 or anti-GPIIb- IIIa MoAb LJ-CP8 into baboons at doses that abolished corresponding agonist-induced aggregation ex vivo (bolus injections of 0.5 mg/kg and 10 mg/kg, respectively) prolonged template bleeding times from baseline values of 4.0 +/- 0.3 minutes to > 27 +/- 4 minutes, and to > 26 +/- 4 minutes, respectively (P 3 .001 in both cases), without affecting the peripheral platelet count (P > .5). However, injection of anti-GPIb MoAb AP1 [10 mg/kg as IgG or 1 mg/kg as F(ab)2 fragments] produced immediate irreversible thrombocytopenia (< 40,000 platelets/microL). Anti-GPIIb-IIIa MoAb LJ-CP8 abolished platelet deposition and fibrin accumulation on collagen segments under both arterial and venous flow conditions (P < .01 in all cases), whereas MoAb BB3 BD5 produced minimal inhibition of platelet deposition and no decrease in fibrin accumulation at arterial shear rates and undetectable antithrombotic outcomes at low shear. Thus, inhibiting GPIIb-IIIa-dependent platelet recruitment abrogates both thrombus formation and platelet hemostatic function at both venous and arterial shear rates. By contrast, interfering with GPIb-vWF-dependent platelet interactions abolishes platelet hemostatic function without producing corresponding antithrombotic effects.


Author(s):  
Agnė Žiniauskaitė ◽  
Vytautas Cėpla ◽  
Tadas Jelinskas ◽  
Romuald Eimont ◽  
Artūras Ulčinas ◽  
...  

There is a growing need for novel in vitro corneal models to replace animal-based ex vivo test in drug permeability studies. In this study we demonstrate a corneal mimetic that models the stromal and epithelial compartments of human cornea. Human corneal epithelial cells (HCE-T) were grown on top of a self-supporting porcine collagen-based hydrogel. Cross sections of the multilayers were characterized by histological staining and immunocytochemistry of zonula occludens-1 protein (ZO-1) and occludin. Furthermore, water content and elastic properties of the synthetized collagen type I-based hydrogels were measured. The apparent permeability coefficient (Papp) values of a representative set of ophthalmic drugs were measured and correlated to rabbit cornea Papp values found in the literature. Multilayered structure of HCE-T cells and expression of ZO-1 and occludin in full thickness of multilayer were observed. The hydrogel-based corneal model exhibited excellent correlation to rabbit corneal permeability (r=0.96), whereas insert-grown HCE-T multilayer was more permeable and the correlation to the rabbit corneal permeability was lower (r=0.89). The hydrogel-based human corneal model predicts the rabbit corneal permeability more reliably in comparison to HCE-T cells grown in inserts. This in vitro human corneal model can be successfully employed for drug permeability tests whilst avoiding ethical issues and reducing costs.


1989 ◽  
Vol 61 (01) ◽  
pp. 057-064 ◽  
Author(s):  
L Badimon ◽  
J J Badimon ◽  
A Galvez ◽  
V Turitto ◽  
V Fuster

SummaryA subgroup of pigs with von Willebrand’s disease from the Mayo Clinic stock shows abnormal platelet aggregation in response to collagen [vWD-Homo(-)], in contrast to the normal aggregation responses observed in the main colony of pigs with homozygous vWD [vWD-Homo(+)]. This subgroup has been characterized at Mayo as a storage pool deficiency due to the reduced levels of ADP and Serotonin in the platelet dense granules. In the present studies, an ex-vivo perfusion chamber was utilized to investigate the deposition of 111In-labeled platelets on aortic subendothelium and collagen type I exposed to blood from vWD-Homo(-), vWD-Homo(+) and normal animals. Both non-anticoagulated and heparinized blood were exposed for wall shear rates ranging from 212 sec-1 to 3380 sec-1 and exposure times as long as 30 min. An enhanced decrease in platelet deposition in the vWD-Homo(-) animals was observed compared to vWD-Homo(+) animals. The decrease was observed primarily at the higher shear rates and was more pronounced in the absence of heparin and on the collagenous substrate. Thus, the abnormality in collagen-induced aggregation, which has been characterized as a storage-pool type defect, results in a decreased platelet deposition compared with that produced by severe vWD alone.


1998 ◽  
Vol 80 (09) ◽  
pp. 437-442 ◽  
Author(s):  
I. Hioki ◽  
K. Onoda ◽  
T. Shimono ◽  
H. Shimpo ◽  
K. Tanaka ◽  
...  

SummaryAlterations in platelet aggregability may play a role in the pathogenesis of qualitative platelet defects associated with cardiopulmonary bypass (CPB). We circulated fresh heparinized whole blood through tubing sets coated with heparin (C group, n = 10) and through non-coated sets (N group, n = 10) as a simulated CPB circuit. Shear stress (108 dyne/cm2)-induced platelet aggregation (hSIPA), plasma von Willebrand factor (vWF) activity and platelet glycoprotein (GP) Ib expression were measured, before, during, and after this in vitro set up of circulation. In the two groups, the extent of hSIPA significantly decreased during circulation and was partially restored after circulation. Decreases in the extent of hSIPA were significantly less with use of heparin-coated circuits. There was an equivalent reduction in plasma vWF activity, in the two groups. Expression of platelet surface GP Ib decreased significantly during circulation and recovered after circulation. Reduction of surface GP Ib expression during circulation was significantly less in the C group than that in the N group. Decrease in surface GP Ib expression correlated (r = 0.88 in either group) with the magnitude of hSIPA, in the two groups. The progressive removal of surface GP Ib was mainly attributed to redistribution of GP Ib from the membrane skeleton into the cytoskeleton. Our observations suggest that use of heparin-coated circuits partly blocks the reduction of hSIPA, as a result of a lesser degree of redistribution of GP Ib.


1983 ◽  
Vol 50 (04) ◽  
pp. 852-856 ◽  
Author(s):  
P Gresele ◽  
C Zoja ◽  
H Deckmyn ◽  
J Arnout ◽  
J Vermylen ◽  
...  

SummaryDipyridamole possesses antithrombotic properties in the animal and in man but it does not inhibit platelet aggregation in plasma. We evaluated the effect of dipyridamole ex vivo and in vitro on platelet aggregation induced by collagen and adenosine- 5’-diphosphate (ADP) in human whole blood with an impedance aggregometer. Two hundred mg dipyridamole induced a significant inhibition of both ADP- and collagen-induced aggregation in human blood samples taken 2 hr after oral drug intake. Administration of the drug for four days, 400 mg/day, further increased the antiplatelet effect. A significant negative correlation was found between collagen-induced platelet aggregation in whole blood and dipyridamole levels in plasma (p <0.001). A statistically significant inhibition of both collagen (p <0.0025) and ADP-induced (p <0.005) platelet aggregation was also obtained by incubating whole blood in vitro for 2 min at 37° C with dipyridamole (3.9 μM). No such effects were seen in platelet-rich plasma, even after enrichment with leukocytes. Low-dose adenosine enhanced in vitro inhibition in whole blood.Our results demonstrate that dipyridamole impedes platelet aggregation in whole blood by an interaction with red blood cells, probably involving adenosine.


2021 ◽  
Vol 8 (3) ◽  
pp. 39
Author(s):  
Britani N. Blackstone ◽  
Summer C. Gallentine ◽  
Heather M. Powell

Collagen is a key component of the extracellular matrix (ECM) in organs and tissues throughout the body and is used for many tissue engineering applications. Electrospinning of collagen can produce scaffolds in a wide variety of shapes, fiber diameters and porosities to match that of the native ECM. This systematic review aims to pool data from available manuscripts on electrospun collagen and tissue engineering to provide insight into the connection between source material, solvent, crosslinking method and functional outcomes. D-banding was most often observed in electrospun collagen formed using collagen type I isolated from calfskin, often isolated within the laboratory, with short solution solubilization times. All physical and chemical methods of crosslinking utilized imparted resistance to degradation and increased strength. Cytotoxicity was observed at high concentrations of crosslinking agents and when abbreviated rinsing protocols were utilized. Collagen and collagen-based scaffolds were capable of forming engineered tissues in vitro and in vivo with high similarity to the native structures.


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