Thrombin-Induced Surface Changes of Human Platelets in Plasma: Their Relation to Serotonin Release

1979 ◽  
Author(s):  
K. Subbarao ◽  
V.V. Kakkar
Keyword(s):  
Membrane Proteins ◽  
Blood Platelets ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein Band ◽  
Human Platelets ◽  
Serotonin Release ◽  
Glycoprotein I ◽  
Reversible Aggregation ◽  
Coomassie Blue ◽  
Labeling Pattern

Membrane proteins of both control and thrombin-treated platelets were labeled by NaB3H4, reduction of Schiff bases formed between pyridoxal 5′-phosphate and protein amino groups. Examination of the labeled polypeptides by SDS-polyacrylamide gel electrophoresis and fluorography disclosed a different labeling pattern for thrombin-treated platelets. The distributions of Coomassie blue-stained protein from treated and untreated cells were, by contrast, almost identical. Fluorographs of control platelets showed a single intensely labeled protein band (mol wt 90,000) whereas with cells exposed to thrombin (30-60 milliunits) about 10 protein bands with mol wts ranging from 43,000 to 200,000 were typically present. Among these were: thrombin-sensitive protein (mol wt 188,000), glycoprotein I (mol wt 150,000) and actin (mol wt 43,000). When serotonin release was prevented, either by reversing platelet aggregation with low amounts of ADP (0.1-0.3 μM) or by preincubating with 3',5'-ADP (20 μM), an inhibitor of both ADP- and thrombin-induced platelet function, the labeling patterns on fluorographs were similar to the control. These results indicate that blood platelets can undergo reversible aggregation without major changes in their surface topography, whereas thrombin-induced serotonin release appears related to structural alterations in platelet membrane proteins.

scholarly journals Glycoprotein V is not the thrombin activation receptor on human blood platelets

Blood ◽  
1986 ◽  
Vol 68 (3) ◽  
pp. 720-725 ◽  
Author(s):  
D Bienz ◽  
W Schnippering ◽  
KJ Clemetson
Keyword(s):  
Platelet Activation ◽  
Polyclonal Antibodies ◽  
Blood Platelets ◽  
Polyacrylamide Gel Electrophoresis ◽  
Human Platelets ◽  
Exchange Chromatography ◽  
Thrombin Activation ◽  
Strong Candidate ◽  
Triton X ◽  
Kinetics Of

Thrombin activation of platelets involves two receptors: glycoprotein Ib (GPIb), which affects the kinetics of the response; and, as a strong candidate for the second, essential receptor, GPV, a hydrophobic, 82-kd glycoprotein with an isoelectric point (pI) of pH 5.85 to 6.55. Whole platelets were treated with endogenous platelets calcium-activated proteases, yielding a major fragment, GPV8, with molecular weight (mol wt) of 79 kilodaltons (kd). The fragment was purified by affinity chromatography on wheat germ agglutinin followed by ion exchange chromatography on DEAE-Sephacel using first a 0 to 0.7-mol/L and then a 0 to 0.3-mol/L NaCl gradient. A rabbit was immunized with the purified GPV8 for preparation of polyclonal antibodies. Crossed immunoelectrophoresis and two-dimensional polyacrylamide gel electrophoresis (PAGE) electrophoretic blotting with the separate phases of a Triton X-114 phase partition of human platelets showed the characteristic pattern of GPV in the hydrophobic phase. During thrombin- induced platelet aggregation GPV is hydrolysed, releasing a fragment, GPVf1, to the supernatant. The fragment GPVf1 still contains a thrombin- binding site. Anti-GPV antibodies blocked GPV proteolysis, but did not inhibit platelet activation induced by thrombin. We conclude that proteolysis of GPV by thrombin is not essential for platelet activation.

scholarly journals Further studies on the interaction between human platelet membrane glycoproteins IIb and IIIa in triton X-100

Blood ◽  
1982 ◽  
Vol 60 (4) ◽  
pp. 894-904 ◽  
Author(s):  
D Pidard ◽  
JP Rosa ◽  
TJ Kunicki ◽  
AT Nurden
Keyword(s):  
Membrane Proteins ◽  
Divalent Cation ◽  
Human Platelet ◽  
Polyacrylamide Gel Electrophoresis ◽  
Indirect Evidence ◽  
Human Platelets ◽  
Platelet Membrane ◽  
Membrane Glycoproteins ◽  
Nonionic Detergent ◽  
Triton X

Abstract Analysis of human platelet membrane proteins by crossed immunoelectrophoresis (CIE) in the presence of Triton X-100 (TX-100) has previously shown that glycoproteins (GP) IIb and IIIa are located in a single immunoprecipitate, band 16.2 To investigate whether IIb and IIIa are associated in a complex, we have analyzed TX-100-solubilized 125I-labeled membrane proteins by density gradient ultracentrifugation using 10%-40% sucrose gradients containing the nonionic detergent. studies were performed using soluble proteins derived from membranes isolated in the presence or absence of EDTA. Analysis of gradient fractions by SDS-polyacrylamide gel electrophoresis showed that in the absence of divalent cation chelation, GP IIb and IIIa penetrated well into the gradient (fractions 15–17). Analysis of fractions 15–17 by CIE revealed the presence of band 16. In contrast, when the membrane proteins were incubated with EDTA prior to or after TX-100 solubilization, IIb and IIIa remained near the top of the gradient (fractions 8–11) and gave separate immunoprecipitates during CIE. Incubation of washed platelet lysates with leupeptin, an inhibitor of the Ca2+-dependent protease of human platelets, had no effect on the shape of the band 16 immunoprecipitate. Thus, for the first time, direct evidence has been obtained that GP IIb and IIIa may form a divalent cation-mediated complex. Calibration of the sedimentation profiles using proteins of known molecular weight suggests that the complex is of limited size. Indirect evidence suggests that the complex is a heterodimer.

scholarly journals Immunochemical characterization of the platelet-specific alloantigen Leka: a comparative study with the PlA1 alloantigen

Blood ◽  
1984 ◽  
Vol 64 (6) ◽  
pp. 1212-1219 ◽  
Author(s):  
N Kieffer ◽  
B Boizard ◽  
D Didry ◽  
JL Wautier ◽  
AT Nurden
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Human Platelets ◽  
Blue Staining ◽  
Igg Antibody ◽  
Immune Disorder ◽  
Immunochemical Characterization ◽  
Coomassie Blue Staining ◽  
Coomassie Blue

Abstract We report the immunochemical characterization of a new platelet- specific alloantigen detected using an IgG antibody isolated from the serum of a patient with posttransfusion purpura (PTP). In indirect immunoprecipitation experiments, the antibody, termed anti-Leka, predominantly precipitated glycoprotein (GP) IIb from Triton X-100 lysates of normal human platelets. In an immunoblot procedure, which involved the transfer of platelet polypeptides separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to nitrocellulose membrane, anti-Leka bound exclusively to GP IIb. Under identical conditions, four anti-PlA1 antibodies each reacted with GP IIIa. No binding of anti-Leka IgG occurred to Leka (-) platelets or to their separated polypeptides although GP IIb was normally detected by Coomassie blue staining. After electrophoresis of reduced platelet proteins, the Leka determinant was localized to the IIb alpha chain. Thus, unlike the PlA1 antigen, the Leka determinant was not destroyed by disulfide reduction. Analysis of platelets from a patient with Glanzmann's thrombasthenia revealed little or no binding in the GP IIb position. Anti-Leka permitted the identification of 76,000 and 60,000 dalton fragments of GP IIb retained by the platelet following chymotrypsin treatment. Our results further highlight the immunogenicity of the GP IIb-IIIa complex. They also suggest that antibodies against GP IIb can cause the thrombocytopenia observed in PTP and that anti-PlA1 antibodies do not account exclusively for the pathophysiology of this immune disorder.

Tachyphylaxis in Human Blood Platelets Induced by Various Agonists and the Effect on Response To other Agonists

1979 ◽  
Author(s):  
P.A. Ruggles ◽  
M.C. Scrutton
Keyword(s):  
Human Blood ◽  
Blood Platelets ◽  
Human Platelets ◽  
Thrombin Receptor ◽  
Common Pathway ◽  
Stimulus Response ◽  
Reversible Aggregation ◽  
Agonist Concentration ◽  
Subsequent Addition ◽  
Human Blood Platelets

Tachyphylaxis of human platelets to ADP, adrenaline, thrombin, 5-HT and vasopressin (VP) was induced by preincubation of stirred citrated PRP with an agonist concentration which induced primary reversible aggregation. The effect was demonstrable within 2 mins, after addition of some of the agonists and persisted for at least 30 mins. The extent of tachyphylaxis showed a positive correlation with agonist concentration used to induce the initial reversible response. Partial aganists at the ADP (2’, 3’-dialcohol ADP) or α-adreno-(clonidine) receptors did not induce significant tachyphylaxis to subsequent addition of the full agonist. In most instances platelets iaade tachyphylactic to a given agonist showed an unchanged or enhanced response to all other agonists including arachidonate. However tachyphylaxis to ADP, 5HT or thrombin was associated with an attenuated response to collagen. Furthermore tachyphylaxis to thrombin also caused attenuation of the response to VP and arachidonate. Induction of tachyphylaxis to VP, or addition of oxytocin (an inhibitor of aggregation induced by VP) had no effect on the response to thrombin. Thus the region of the thrombin receptor responsible for induction of tachyphylaxis to this agonist is not identical with that at which VP interacts. If stimulus-response coupling involves a common pathway for most agonists these data suggest that development of tachyphylaxis depends on events which preceed the effect of the agonists en this common pathway.

scholarly journals Short communication: possible association of newly absorbed serotonin with nonmetabolic, granule-located adenine nucleotides in human blood platelets

Blood ◽  
1975 ◽  
Vol 45 (3) ◽  
pp. 413-416
Author(s):  
H Holmsen ◽  
CA Setkowsky ◽  
HJ Day
Keyword(s):  
Guinea Pig ◽  
Human Blood ◽  
Short Communication ◽  
Adenine Nucleotides ◽  
Blood Platelets ◽  
Human Platelets ◽  
Serotonin Release ◽  
Release Reaction ◽  
Human Blood Platelets

[3H]-adenine-labeled human platelets in plasma were incubated with or without nonradioactive serotonin. Release reaction was then induced by ADP, epinephrine, collagen, or thrombin. Platelets that had been incubated with serotonin released four times as much serotonin as platelets incubated without serotonin. The specific radioactivities of the ATP and ADP released to plasma during release reaction induced with all four inducers were the same in both systems. This shows that when serotonin is taken up by human platelets, it enters the compartment containing nonmetabolic, granula-stored ATP, and not the compartment with metabolic extragranular ATP. These results suggest that the mechanism of serotonin storage in human platelets is similar to that in other species investigated, i.e., rabbit, guinea pig, and pig.

Interaction of β2-Glycoprotein-I with Human Blood Platelets: Influence Upon the ADP-Induced Aggregation

1985 ◽  
Vol 54 (02) ◽  
pp. 397-401 ◽  
Author(s):  
Johannes Nimpf ◽  
Helmut Wurm ◽  
Gerhard M Kostner
Keyword(s):  
Binding Sites ◽  
Specific Binding ◽  
Blood Platelets ◽  
Gel Filtration ◽  
Human Platelets ◽  
Glycoprotein I ◽  
Unspecific Binding ◽  
Induced Aggregation ◽  
Human Blood Platelets

SummaryThe interaction of β2-glycoprotein-I (β2-G-I), a plasma constituent of unknown function, with blood platelets was studied. The following results were obtained: 1) β2-G-I binds to washed human platelets isolated by centrifugation (WP) at one kind of specific, saturable binding sites. The dissociation constant was found to be approx. 1 × 10−6M.2) In the presence of physiological concentrations of Ca++ (2.5 mM), this specific binding is markedly reduced. Unspecific binding of β2-G-I to platelets, however, is not influenced by Ca++.3) Platelets prepared by gel filtration (GFP), differing in their in vitro aggregability from WP, exhibit no specific binding of β2-G-I. Binding to GFP is also not induced by activation with thrombin, collagen or ADP.4) β2-G-I causes significant alteration of the ADP-induced aggregation of GFP. Aggregation induced by thrombin, collagen, arachidonic acid or PAF-acether, however is not altered by β2G-I.It is suggested, that pelleting during centrifugation causes irreversible rearrangements in the membrane of platelets.

scholarly journals Effects of Lectins on Blood Platelets from Various Species

1977 ◽  
Author(s):  
O. Tangen ◽  
B. Karlstam ◽  
S. Bygdeman
Keyword(s):  
Shape Change ◽  
Blood Platelets ◽  
Human Platelets ◽  
Serotonin Release ◽  
Variable Degree ◽  
Con A ◽  
Platelet Release ◽  
Induced Aggregation ◽  
Aggregation Of Platelets ◽  
Platelet Shape

Earlier it has been shown that different lectins induce a variable degree of aggregation of platelets. The present study confirmed previous data and demonstrated that wheat germ agglutinin (WGA) was very active, 1eucoagglutinin had about a tenth of the activity of WGA on a concentration basis, and Con A had a weak aggregating effect on human gel filtered platelets (GFP). Soy bean lectin did not aggregate human GFP.The fact that adenosine inhibited WGA- and leucoagglutinin-induced aggregation that WGA and Con A caused serotonin release, and that the aggregation- curves indicated platelet shape change are indications that the lectins influenced glycosyl moieties involving one or more molecules relevant to release and aggregation reaction.GFP were markedly more responsive to the lectins than platelets in plasma, probably due to interfering glycosyl groups amongst the plasma constituents.Platelets from man, rabbit, rat, cow and pig reacted differently towards the lectins, human platelets being the most reactive and bovine and porcine platelets being almost unreactive. These results pose intriguing questions regarding the glycosyl content of platelet membranes in different species and their relation to platelet release and aggregation.

scholarly journals Interaction between vaccinia virus and human blood platelets

Blood ◽  
1982 ◽  
Vol 59 (3) ◽  
pp. 482-487 ◽  
Author(s):  
T Bik ◽  
I Sarov ◽  
A Livne
Keyword(s):  
Vaccinia Virus ◽  
Electrostatic Interactions ◽  
Blood Platelets ◽  
Human Platelets ◽  
Serotonin Release ◽  
Metabolic Inhibitors ◽  
Platelet Surface ◽  
Neuraminidase Activity ◽  
Viral Particles ◽  
Viral Adsorption

Abstract The objective of the present study was to characterize the interaction between human platelets and vaccinia virus and to examine possible impairment of platelet functions. The vaccinia virus was selected for our model system because it lacks detectable neuraminidase activity. Platelets were incubated with purified viral particles labeled with 3H- thymidine and binding parameters were analyzed. Binding reached saturation with an average of 5 particles/platelet. It was not affected by the plasma but was sensitive to temperature and to metabolic inhibitors. 3H-thymidine-labeled vaccinia virus and formaldehyde-fixed platelets were used to measure viral adsorption. The adsorption was temperature-independent but was affected by ionic strength, indicating electrostatic interactions. Treatment of the fixed platelets with neuraminidase or with alkaline phosphatase reduced viral adsorption, indicating that sialate and phosphate residues on the platelet surface may be involved in the adsorption. Platelet activities were markedly affected by vaccinia virus. The virus caused a dramatic 14C-serotonin release with no added inducer. The release was inhibited by aspirin, a known inhibitor of serotonin release related to prostaglandin synthesis. Furthermore, the virus inhibited platelet aggregation, induced by either ADP, collagen, or thrombin. This study demonstrates that although vaccinia virus lacks neuraminidase activity, it does bind to platelets and affects their function.

scholarly journals Effects of collagen, ionophore A23187 and prostaglandin E1 on the phosphorylation of specific proteins in blood platelets

1979 ◽  
Vol 178 (2) ◽  
pp. 397-406 ◽  
Author(s):  
Richard J. Haslam ◽  
James A. Lynham ◽  
Joan E. B. Fox
Keyword(s):  
Cyclic Amp ◽  
Prostaglandin E1 ◽  
Blood Platelets ◽  
Short Circuit ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Human Platelets ◽  
Ionophore A23187 ◽  
Release Reaction ◽  
Specific Proteins

Human platelets that had been preincubated with 5-hydroxy[3H]tryptamine and [32P]Pi were stirred with various agents; the secretion of 5-hydroxy[3H]tryptamine from platelet granules and the radioactivity of platelet [32P]phosphopolypeptides separated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis were then measured. Exposure of the platelets to collagen fibres or ionophore A23187 selectively increased the phosphorylation of polypeptides with apparent mol.wts. of 47000 (P47) and 20000 (P20) by approx. 3-fold, in association with the release of 5-hydroxy[3H]tryptamine. The 47000-mol.wt. phosphopolypeptide (P47) was clearly separated from platelet actin by the electrophoresis system used. Prostaglandin E1, which inhibits platelet function by increasing platelet cyclic AMP, decreased the phosphorylation of polypeptides caused by collagen as well as the release of 5-hydroxy[3H]tryptamine. Prostaglandin E1 also selectively increased the phosphorylation of distinct polypeptides with apparent mol.wts. of 24000 (P24) and 22000 (P22) by approx. 2-fold. As the phosphorylation reactions caused by collagen are probably mediated by an increase in Ca2+ concentration in the platelet cytosol and may have a role in the release reaction [Haslam & Lynham (1977) Biochem. Biophys. Res. Commun.77, 714–722; (1978) Thromb. Res.12, 619–628], we suggest that a cyclic AMP-dependent phosphorylation of the 24000- and/or 22000-mol.wt. polypeptides caused by prostaglandin E1 may initiate processes that decrease the Ca2+ concentration in the cytosol, so inhibiting both the Ca2+-dependent phosphorylation reactions and the release reaction. Treatment of platelets with prostaglandin E1 did not inhibit the increased phosphorylation of polypeptides with apparent mol.wts. of 47000 and 20000 (P47 and P20) caused by ionophore A23187, which may therefore short-circuit cyclic AMP-dependent mechanisms that decrease the Ca2+ concentration in the platelet cytosol. As prostaglandin E1 did inhibit the release of 5-hydroxy[3H]tryptamine by ionophore A23187, cyclic AMP may also inhibit the release reaction by additional mechanisms.

The Reduced Aggregation Response Of Bernard-Soulier Platelets To Thrombin May Be Related To An Abnormal Glycoprotein V

1981 ◽  
Author(s):  
A T Nurden ◽  
D Dupuis
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Human Platelets ◽  
Surface Proteins ◽  
Galactose Oxidase ◽  
Blue Staining ◽  
Lag Phase ◽  
Coomassie Blue Staining ◽  
Aggregation Response ◽  
Coomassie Blue ◽  
Sds Page

Both platelet membrane GP Ib and GP V have been proposed as receptors for the activation of human platelets by thrombin. Bernard-Soulier (B-S) platelets exhibit a reduced aggregation response to thrombin with a lag phase that precedes aggregation. When B-S platelets, whose surface proteins had been labelled with (125I), were analysed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by PAS-staining, Coomassie blue staining or autoradiography, the apparent absence of GP Ib and the normal presence of GP IIb, IIIa and IIIb was demonstrated. On the basis of such studies several authors have stated that “GP I” is the thrombin receptor. However, GP V is not located by the above procedure, requiring more sensitive analytical methods for its detection. To meet this requirement washed platelets isolated from 3 B-S patients have been treated sequentially with neuraminidase, galactose oxidase and sodium(3H,)-boro- hydride. The labelled platelets were analysed by SDS-PAGE using 7-12% gradient acrylamide gels and the (3H,)-labelled GP’s located by fluorography. In addition to the GP Ib defect the platelets of each B-S patient were lacking the band corresponding to GP V of normal platelets. In agreement with previous studies we observed that when (3H,)-labelled normal human platelets were incubated with thrombin GP V (Mr=82,000) was hydrolysed,and that this was accompanied by the appearance of a labelled glycopeptide (Mr=69,500) in the supernatant. When (3H)-labelled B-S platelets were treated with thrombin no labelled glycopeptide was located. GP V could therefore be either absetit from B-S platelets or have a modified carbohydrate composition rendering it insensitive to the analytical procedure used. Interpretations into the reduced aggregation response of B-S platelets to thrombin should be extended to include a possible GP V defect.

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