Mechanisms of Cellular Activation by Platelet Microparticles

Introduction

Eukaryotic cells, after activation, shed components of their plasma membranes into the extracellular space.^1,2 Such fragments may include cytoplasmic elements and are known colloquially as microparticles (MPs). Monocytes,³ lymphocytes,⁴ endothelial cells,⁵ erythrocytes,⁶ and granulocytes⁷ have been shown to vesiculate either in vitro or in vivo. MPs from other sources have also been reported to exist in vivo.^8,9 In addition, platelets have been found to vesiculate following activation by agonists.^10,11 Platelets activated with collagen and/or thrombin, by the Ca²⁺ ionophore A23187 or the complement protein C5b-9, induce platelet microparticle (PMP) formation. While the effect of these agonists is to increase platelet cytosolic Ca²⁺ concentration, it has been suggested that calpain activation,^12-14 cytoskeletal reorganization,^12,14,15 protein phosphorylation¹⁴ and phospholipid translocation^16,17 also may have roles in PMP formation.

Shear stress has been shown to induce platelet vesiculation. The mechanisms involved include the binding of von Willebrand factor (vWF) to either glycoprotein (GP)-Ib or GP IIb/IIIa.¹⁸ These in vitro observations are supported by an ex vivo model of high arterial shear stress. High shear stress, as pertains in the atherosclerotic vasculature, was shown to activate platelets and trigger PMP formation. Meanwhile, under physiological or simulated shear stress conditions in arteries with a minor degree of stenosis, no vesiculation occurred.¹⁹

Platelet microparticles contain surface receptors for both factor VIII, a cofactor in the tenase enzyme complex,²⁰ and factor Va (which assembles with factor Xa to form the prothrombinase complex).¹⁰ While a transient expression of platelet membrane factor VIII binding has been reported, more stable factor VIII and factor Va has been reported for PMPs.²⁰ High- and low-affinity binding sites for activated factor IX are also present on PMPs.²¹ Thus, PMPs have the potential to provide procoagulant activity at a distance from the site of platelet activation and for a longer period than activated platelets. Also, PMPs possess anticoagulant properties.²² These PMPs can bind protein S, an anticoagulant plasma protein responsible for degradation of the phospholipid-bound coagulation factor Va and factor VIII and which supports the binding of both protein C and activated protein C (APC). Coupled to the same platelet stimulation reactions, PMPs possess both pro- and anticoagulant properties. The relative distribution of pro- and anticoagulant activity between platelets and PMP remains approximately the same, irrespective of the agonist used, with approximately 25% of both activities associated with PMP. Furthermore, a recent study reported that protein C inhibitor, a member of the serpin family secreted from activated platelets, binds preferentially to the phosphatidylethanolamine (PE) of platelet membranes and PMPs, and efficiently inhibits phospholipid-bound APC.²³

Similar to PMPs, MPs released from monocytes, lymphocytes, erythrocytes, and granulocytes demonstrate procoagulant activity, but whether they display anti-coagulant activity remains to be shown. The density of aminophospholipids also has been shown to be greater on PMPs than on remnant platelets.^24,25 This may account for the preferential binding to PMPs over platelets of factor VIII,²⁰ factor Va,¹⁰ and factor IXa.²¹ The PMP surface may provide the optimal phosphatidylserine (PS) level required by the binding sites of these blood clotting factors. Preferential binding of these critical factors favor the participation of PMPs in hemostatic protection and may explain the lack of bleeding symptoms in patients with autoimmune thrombocytopenia associated with high levels of PMPs.²⁶

Elevated levels of PMPs in vivo have been reported for patients with activated coagulation and fibrinolysis,²⁷ unstable angina,²⁸ diabetes mellitus,²⁹ sickle cell anemia,³⁰ and human immunodeficiency virus (HIV).³¹ Recently, it was demonstrated for the first time that PMPs generated in vivo can stimulate coagulation.³² Procoagulant PMPs generated during coronary bypass surgery, especially in pericardial blood, supported coagulation via a tissue factor (TF)/ factor VII-dependent and factor XII-independent pathway.

The functional importance of PMPs in human disease has not been well-defined. This is despite their pro- and anticoagulative properties^10,16,20,22 and the convincing evidence that the PMP surface possesses the platelet—endothelium attachment receptors, glycoprotein GP IIb/IIIa, Ib, and IaIIa^33-35 and P-selectin.³⁴ Despite the association of PMPs with a range of clinical abnormalities,^26-31,36 it remains unsolved whether persistent platelet activation, with concomitant formation of PMPs, is merely a consequence of the disease or reflects the influence of previously formed PMPs in the circulation.

PMPs have become a popular focus of research, for both clinical and basic investigation. Recently, the possibility that MPs might, themselves, evoke cellular responses in the immediate microenvironment of their formation has been suggested. For example, endothelial cell activation by thrombin results in vesicle shedding, which, in turn, activates neutrophils and enhances their propensity to adhere to endothelial cells.³⁷ Similarly, MPs shed from platelets activated with Staphylococcus aureus α-toxin induce platelet aggregation.³⁸

The role of PMPs in modulating their local environment is the subject of this review. An overview of the mechanism(s) of cellular activation by PMPs will be provided. PMP-induced activation of platelets, human umbilical vein endothelial cells (HUVECs), monocytes, and U-937 (human promonocytic leukemia) cells have been used as models for assessing the possible biological effects of PMPs in vivo.

• References

• 1 Armstrong MJ, Storch J, Dainiak N. Stimulating distinct plasma membrane regions gives rise to extracellular membrane vesicles in normal and transformed lymphocytes. Biochim Biophys Acta 1998; 946: 106-112.
• 2 Bos-Vreugdenhil AP, Poldermans JE, Ruitenbeek MM, Nieuw-Amerongen AV, Roukema PA. Study on membrane fragments released from the sublingual glands of the mouse during secretion in vitro and in vivo. J Biol Buccale 1985; 13: 317-332.
• 3 Satta N, Toti F, Feugeas O, Bohbot A, Dachery-Prigent J, Eschwege V, Hedman H, Freyssinet JH. Monocyte vesiculation is a possible mechanism for dissemination of membrane-associated procoagulant activities and adhesion molecules after stimulation by lipopolysaccharide. J Immunol 1994; 153: 3245-3255.
• 4 Mallat Z, Hugel B, Ohan J, Leseche G, Freyssinet JM, Tedgui A. Shed membrane microparticles with procoagulant potential in human atherosclerotic plaques. Circulation 1999; 99: 348-353.
• 5 Leeuwenberg JF, Smeets EF, Neefjies JJ, Shaffer MA, Cinek T, Jeunhomme TM, Ahern TJ, Buurman WA. E-selectin and intracellular adhesion molecule-1 are released by activated human endothelial cells in vitro. Immunology 1992; 77: 543-549.
• 6 Allan D, Thomas P. Ca²⁺-induced biochemical changes in human erythrocytes and their relation to microvesiculation. Biochem J 1981; 198: 433-440.
• 7 Nieuwland R, Berckmans RJ, Rotteveel-Eijkman RC, Maquelin KN, Roozendaal KJ, Jansen P, ten Have L, Kijsman L, Hack CE, Sturk A. Cell-derived microparticles generated in patients during cardiopulmonary bypass are highly procoagulant. Circulation 1997; 96: 3534-3541.
• 8 Gris J-C, Toulon P, Brun S, Maugard C, Sarlat C, Schved J-F, Berlan J. The relationship between plasma microparticles, protein S and anticardiolipin antibodies in patients with human immunodeficiency virus infection. Thromb Haemost 1996; 76: 38-45.
• 9 Aupeix K, Hugel B, Martin T, Bischoff P, Lill H, Pasquali J-L, Freyssinet J-M. The significance of shed membrane particles during programmed cell death in vitro and in vivo in HIV-1 infection. J Clin Invest 1997; 99: 1546-1554.
• 10 Sims PJ, Faioni EM, Wiedmer T, Shattil SJ. Complement proteins C5b-9 cause release of membrane vesicles from the platelet surface that are enriched in the membrane receptor for coagulation factor Va and express prothrombinase activity. J Biol Chem 1988; 263: 18205-18212.
• 11 Sims PJ, Wiedmer T, Esmon CT, Weiss HJ, Shattil SJ. Assembly of the platelet prothrombinase complex is linked to vesiculation of the platelet plasma membrane. J Biol Chem 1989; 264: 17049-17057.
• 12 Fox JEB, Austin CD, Boyles JK, Steffen PK. Role of the membrane cytoskeleton in preventing the shedding of procoagulant-rich microvesicles from the platelet plasma membrane. J Cell Biol 1990; 111: 483-493.
• 13 Fox JEB, Austin CD, Reynolds CC, Steffen DK. Evidence that agonist-induced activation of calpain causes shedding of procoagulant-containing microvesicles from the membrane of aggregating platelets. J Biol Chem 1991; 266: 13289-13295.
• 14 Yano Y, Shiba E, Kambayashi J-I, Sakon M, Kawasaki T, Fujitani K, Kang J, Mori T. The effects of calpeptin (a calpain specific inhibitor) on agonist induced microparticle formation from the platelet plasma membrane. Thromb Res 1994; 71: 385-396.
• 15 Basse F, Gaffet P, Bienvenue A. Correlation between inhibition of cytoskeleton proteolysis and anti-vesiculation effects of calpain during A23187-induced activation of human platelets: are vesicles shed by filopod fragmentation. Biochem Biophys Acta 1994; 1190: 217-224.
• 16 Bevers EM, Comfurius P, Zwaal RFA. Platelet procoagulant activity. Physiological significance and mechanisms of exposure. Blood Rev 1991; 5: 146-154.
• 17 Dachery-Prigent J, Pasquet J-M, Freyssinet J-M, Nurden AT. Calcium involvement in aminophospholipid exposure and microparticle formation during platelet activation: a study using Ca²⁺-ATPase inhibitors. Biochemistry 1995; 34: 11625-11634.
• 18 Miyazaki Y, Nomura S, Miyake T, Kagawa H, Kitada C, Taniguchi H, Komiyama Y, Fujimura Y, Ikeda Y, Fukuhara S. High shear stress can initiate both platelet aggregation and shedding of procoagulant containing microparticles. Blood 1996; 88: 3456-3464.
• 19 Holme PA, Orvim U, Hamers MJAG, Solum NO, Brosstad FR, Barstad RM, Sakariassen KS. Shear-induced platelet activation and platelet microparticle formation at blood flow conditions as in arteries with a severe stenosis. Arter Thromb Vasc Biol 1997; 17: 646-653.
• 20 Gilbert GE, Sims PJ, Wiedmer T, Furie B, Furie BC, Shattil SJ. Platelet-derived microparticles express high affinity receptors for factor VIII. J Biol Chem 1991; 266: 17261-17268.
• 21 Hoffman M, Monroe DM, Roberts HR. Coagulation factor IXa binding to activated platelets and platelet-derived microparticles: a flow cytometric study. Thromb Haemost 1992; 68: 74-78.
• 22 Tans G, Rosing J, Thomassen MC, Heeb MJ, Zwaal RFA, Griffin JH. Comparison of anticoagulant and procoagulant activities of stimulated platelets and platelet-derived microparticles. Blood 1991; 77: 2641-2648.
• 23 Nishioka J, Ning M, Hayashi T, Suzuki L. Protein C inhibitor secreted from activated platelets efficiently inhibits activated protein C on phosphatidylethanolamine of platelet membrane and microvesicles. J Biol Chem 1998; 273: 11281-11287.
• 24 Dachery-Prigent J, Freyssinet J-M, Pasquet J-M, Carron J-C, Nurden AT. Annexin V as a probe of aminophospholipid exposure and platelet membrane vesiculation: a flow cytometry study showing a role for free sulfhydryl groups. Blood 1993; 81: 2554-2565.
• 25 Pasquet J-M, Dachery-Prigent J, Nurden AT. Calcium influx is a determining factor of calpain activation and microparticle formation in platelets. Eur J Biochem 1996; 239: 647-654.
• 26 Jy W, Horstman LL, Acre M, Ahn YS. Clinical significance of platelet microparticles in autoimmune thrombocytopenias. J Lab Clin Med 1992; 119: 334-345.
• 27 Holme PA, Solum NO, Brosstad F, Roger M, Abdelnoor M. Demonstration of platelet-derived microvesicles in blood from patients with activated coagulation and fibrinolysis using a filtration technique and western blotting. Thromb Haemost 1994; 72: 666-671.
• 28 Singh N, Gemmell CH, Daly PA, Yeo EL. Elevated platelet-derived microparticle levels in unstable angina. Can J Cardiol 1995; 11: 1015-1021.
• 29 Strano A, Davi G, Patrono C. In vivo platelet activation in diabetes mellitus. Sem Thromb Haemost 1991; 17: 422-425.
• 30 Wun T, Paglieroni T, Rangaswami A, Franklin PH, Welborn J, Cheung A, Tablin F. Platelet activation in patients with sickle cell disease. Br J Haem 1998; 100: 741-749.
• 31 Holme PA, Muller F, Solum NO, Brosstad F, Froland SS, Aukrust P. Enhanced activation of platelets with abnormal release of RANTES in human immunodeficiency virus type 1 infection. FASEB J 1998; 12: 79-90.
• 32 Nieuwland R, Berckmans RJ, Rotteveel-Eijkman RC, Maquelin KN, Roozendaal KJ, Jansen PGM, ten Have K, Eijsman L, Hack CE, Sturk A. Cell-derived microparticles generated in patients during cardiopulmonary bypass are highly procoagulant. Circulation 1997; 96: 3534-3541.
• 33 George JN, Pickett EB, Saucerman S, McEver RP, Kunicki TJ, Newman PJ. Platelet surface glycoproteins: studies on resting and activated platelets and platelet membrane microparticles in normal subjects, and observations in patients during adult respiratory distress syndrome and cardiac surgery. J Clin Invest 1986; 78: 340-348.
• 34 Abrams CS, Ellison N, Budzynski AZ, Shattil SJ. Direct activation of activated platelets and platelet-derived microparticles in humans. Blood 1990; 75: 128-138.
• 35 Wencel-Drake JD, Dieter MG, Lam SC-T. Immunolocalization of β1 integrins in platelets and platelet-derived microvesicles. Blood 1993; 82: 1197-1203.
• 36 Silijander P, Carpen O, Lassilia R. Platelet-derived microparticles associate with fibrin deposition during thrombosis. Blood 1996; 87: 4651-4663.
• 37 Bizios R, Lai LC, Cooper JA, Del Vecchio PJ, Malik AB. Thrombin-induced adherence of neutrophils to cultured endothelial monolayers: increased endothelial adhesiveness. J Cell Physiol 1988; 134: 275-280.
• 38 Fourcade O, Simon MF, Viode C, Rugani FL, Ragab A, Fournie B, Sarda L, Chap H. Secretory phospholipase A₂ generates the novel lipid mediator lysophosphatidic acid in membrane microvesicles shed from activated cells. Cell 1995; 80: 919-927.
• 39 Barry OP, Pratico D, Lawson JA, FitzGerald GA. Transcellular activation of platelets and endothelial cells by bioactive lipids in platelet microparticles. J Clin Invest 1997; 99: 2118-2127.
• 40 Smith WL, Marnett LJ. Prostaglandin endoperoxide synthase: structure and catalysis. Biochim Biophys Acta 1991; 1083: 1-17.
• 41 Barry OP, Kazanietz MG, Pratico D, FitzGerald GA. Arachidonic acid in platelet microparticles upregulates cyclooxygenase-2 dependent prostaglandin formation via a protein kinase C/mitogen-activated protein kinase-dependent pathway. J Biol Chem 1999; 274: 7545-7556.
• 42 Smith WL, DeWitt DL. Prostaglandin Endoperoxide H Synthases-1 and 2. In: Dixon FJ. ed Advances in Immunology. vol. 62. Orlando, FL: Academic Press; 1996: 167-215.
• 43 Jones DA, Carlton DP, McIntyre TM, Zimmerman GA, Prescott SM. Molecular cloning of human prostaglandin endoperoxide synthase type II and demonstration of expression in response to cytokines. J Biol Chem 1993; 268: 9049-9054.
• 44 Wilentz JR, Sanborn TA, Haudenschild CC, Valeri CR, Ryan TJ, Faxon DP. Platelet accumulation in experimental angioplasty: time course and relation to vascular injury. Circulation 1987; 75: 636-642.
• 45 Wissler RW. Update on the pathogenesis of atherosclerosis. Am J Med 1991; 91: 35-95.
• 46 Nomura S, Suzuki M, Katsura K, Xie GL, Miyazaki Y, Miyake T, Kido H, Kagawa T, Fukahara S. Platelet-derived microparticles may influence the development of atherosclerosis in diabetes mellitus. Atherosclerosis 1995; 116: 235-240.
• 47 Kelton JG, Warkentin TE, Hayward CPM, Murphy WG, Moore JC. Calpain activity in patients with thrombotic thrombocytopenic purpura is associated with platelet microparticles. Blood 1992; 80: 2246-2251.
• 48 Davies PF, Tripathi SC. Mechanical stress mechanisms and the cell. An endothelial paradigm. Circ. Res 1993; 72: 239-245.
• 49 Barry OP, Pratico D, Savani RC, FitzGerald GA. Modulation of monocyte-endothelial cell interactions by platelet microparticles. J Clin Invest 1998; 102: 136-144.
• 50 Satta N, Toti F, Feugeas O, Bohbot A, Dachary-Prigent J, Eschwege V, Hedmna H, Freyssinet JH. Monocyte vesiculation is a possible mechanism for dissemination of membrane-associated procoagulant activities and adhesion molecules after stimulation by lipopolysaccharide. J Immunol 1994; 153: 3245-3255.
• 51 Marcus AJ, Weksler BB, Jaffe EA, Broekman MJ. Synthesis of prostacyclin from platelet-derived endoperoxides by cultured human endothelial cells. J Clin Invest 1980; 66: 9797-9806.
• 52 Marcus AJ, Broekman MJ, Safier LB, Ullman HL, Islam N, Serhan CN, Weissman G. Production of arachidonic acid lipoxygenase products during platelet-neutrophil interactions. Clin Physiol Biochem 1984; 2: 78-83.
• 53 Marcus AJ. Eicosanoid interaction between platelets, endothelial cells, and neutrophils. Methods Enzymol. 1990; 187: 585-599.
• 54 Zembowicz A, Jones SL, Wu KK. Induction of cyclooxygenase-2 in human umbilical vein cells by lysophosphatidylcholine. J Clin Invest 1995; 96: 1688-1692.
• 55 Reiser COA, Lanz T, Hofmann F, Hofer G, Rupprecht HD, Goppelt-Struebe M. Lysophosphatidic acid-mediated signal-transduction pathways involved in the induction of the early-response genes prostaglandin G/H synthase-2 and Egr-1: a critical role for the mitogen-activated protein kinase p38 and for Rho proteins. Biochem J 1998; 330: 1107-1114.
• 56 Pratico D, Lawson JA, FitzGerald GA. Cyclooxygenase dependent formation of the isoprostane 8-epi-PGF_2α . J Biol Chem 1995; 270: 9800-9808.
• 57 Maclouf J, Folco G, Patrono C. Eicosanoids and iso-eicosanoids: constitutive and transcellular biosynthesis in vascular disease. Haem Thromb 1998; 79: 691-795.
• 58 Minuz P, Andrioli G, Degan M, Gaino S, Ortolani R, Tommasoli R, Zuliani V, Lechi A, Lechi C. The F₂-isoprostane 8-epiprostaglandin F_2α increases platelet adhesion and reduces anti-adhesive and antiaggregatory effects of NO. Arter Thromb Vasc Biol 1998; 18: 1248-1256.
• 59 Pratico D, Iuliano L, Mauriello A, Spagnoli L, Lawson JA, Maclouf J, Violi F, FitzGerald GA. Localization of F₂-isoprostanes in human atherosclerotic lesions. J Clin Invest 1997; 100: 2028-2034.
• 60 Dekker LV, Parker PJ. Protein kinase C-a question of specificity. Trends Biochem Sci 1994; 19: 73-77.
• 61 Nishizuka Y. Intracellular signaling by hydrolysis of phospholipids and activation of protein kinase C. Science 1992; 258: 607-614.
• 62 Cano E, Mahadevan LC. Parallel signaling processing among mammalian MAPKs. Trends Biochem Sci 1995; 20: 117-122.
• 63 Gupta S, Barrett T, Whitmarsch AJ, Cavanagh J, Sluss HK, Derijard B, Davis RJ. Selective interaction of JNK protein kinase isoforms with transcription factors. EMBO J 1996; 15: 2760-2770.
• 64 Lee JC, Laydon JT, McDonnell PC, Gallagher TF, Kumar S, Green D, McNulty D, Blumenthal MJ, Heys JR, Landvatter SW, Strickler JE, McLaughlin MM, Siemens IR, Fischer SM, Livi GP, White JR, Adams JL, Young PR. A protein kinase involved in the regulation of inflammatory cytokine biosynthesis. Nature 1994; 372: 739-746.
• 65 Kyriakis JM, Banerjee P, Nikolakaki E, Dai T, Rubie EA, Ahmad MF, Avruch J, Woodgett JR. The stress-activated protein kinase subfamily of c-Jun kinases. Nature 1994; 369: 156-160.