Plasminogen Activation System in Platelet Pathophysiology: Comparison
View Latest Version
Please note this is a comparison between Version 3 by Jason Zhu and Version 2 by Jason Zhu.

Traditionally, platelets have been exclusively considered for their procoagulant and antifibrinolytic effects during normal activation of hemostasis. Effectively, activated platelets secrete coagulation factors, expose phosphatidylserine, and promote thrombin and fibrin production. In addition to procoagulant activities, platelets confer resistance of thrombi to fibrinolysis by inducing clot retraction of the fibrin network and release of huge amounts of plasminogen activator inhibitor-1, which is the major physiologic inhibitor of the fibrinolytic cascade. However, the discovery of multiple relations with the fibrinolytic system, also termed Plasminogen Activation System (PAS), has introduced new perspectives on the platelet role in fibrinolysis. Indeed, the activated membrane surface of platelets provides binding sites on which fibrinolytic enzymes can be activated.

  • fibrinolysis
  • plasminogen
  • plasmin

1. Plasminogen as Zymogen Form

The possibility that plasminogen is released from platelet organelles or that platelets express specific receptors for plasminogen binding outlines a new chapter on the platelet functions in the physiological and pathological hemostasis. The increasingly accepted hypothesis is that platelets provide a mechanism for the localization of plasminogen at a site of fibrin formation, thereby enhancing the fibrinolytic cascade [1].
Firstly, Coppinger et al. showed that platelets are able to release plasminogen upon thrombin stimulation [2]. Proteomic analysis of platelet α-granules using mass spectrometry demonstrated that plasminogen is contained in α-granules, but it has not yet clarified whether the alpha-granular pool contains Lys- or Glu-plasminogen [3]. Notably, plasminogen was undetectable in megakaryocyte cultures unless the cell culture was exposed to the media containing plasma, probably due to an endocytic mechanism by these cells [4]. Secondly, it has been established that plasminogen interacts with human platelets, and the binding is enhanced fivefold by thrombin stimulation [5]. Multiple receptors for plasminogen have been described in various cell types, and a common feature of these receptors is that they interact with plasminogen via its lysine binding sites located in the kringle domains. This lysine-dependent binding mechanism was confirmed by the treatments with lysine analog ε-aminocaproic acid and carboxypeptidase B [5][6][7]. It has been established that plasminogen, associated with the platelet surface, assumes an open conformation that is more readily cleaved to plasmin by activators and is protected from inhibition by α2-antiplasmin [5][8][9][10].
Of the platelet surface proteins, the integrin αIIbβ3 seems to be the main plasminogen-binding site. Miles and Plow demonstrated that plasminogen binds to the fibrinogen receptor αIIbβ3 on platelets and that thrombin stimulation increases plasminogen binding [5]. Subsequently, Adelman et al. showed that plasminogen binding to platelet αIIbβ3 may be mediated via plasminogen associated with fibrinogen through lysine binding domains [7].
Whyte et al. provided new insights on the location and the role of plasminogen in in vitro model for thrombus formation and lysis under flow conditions. The researchers found that adherent spread platelets accumulate plasminogen in an αIIbβ3-dependent manner, whereas PS-exposing platelets directly bind plasminogen through protruding caps or indirectly via platelet-associated fibrinogen. Notably, PS-exposing platelets did not express αIIbβ3, as demonstrated by the lack of PAC-1 (activated GP IIb/IIIa) staining in the platelet caps. Altogether, these data indicated that PS-exposing platelets foster the conversion of plasminogen into plasmin, thus modulating local fibrinolysis within the microenvironment of the thrombus [11].
Plg-Rkt is an integral transmembrane receptor synthesized with a C-terminal lysine, firstly identified on the macrophage surface, which promotes plasminogen activation, cell migration, and polarization. More recently, Whyte et al. demonstrated the presence of Plg-Rkt on the platelet surface. Genetic ablation of Plg-Rkt reduces plasminogen binding by roughly 50%, suggesting the central role of this receptor in the retention of plasminogen on the activated platelets [12].

2. Plasmin

It is conceivable that platelets are involved in the plasmin positive feedback loop; once released from platelets, plasmin can participate in mechanisms that further enhance platelet activities. However, it is still unclear whether plasmin exerts an activating or inhibiting action on platelets [13]. It is certain that experimental temperature, incubation time, plasmin concentration, and presence of plasma proteins modify plasmin effects on human platelets in vitro [1].
Niewiarowski et al. were the first to introduce the concept of plasmin as a platelet activator. The researchers demonstrated that plasmin could induce reversible platelet aggregation and significant granule release. The short treatment of platelets with plasmin enhanced their sensitivity to ADP, a key agonist for platelet aggregation [14]. The study of biochemical mechanisms indicated that plasmin at high doses caused aggregation and secretion of washed human platelets associated with Ca2+ mobilization and phospholipase C and protein kinase C activation, suggesting the involvement of Gq protein [8]. In line with these studies, Ishii-Watabe et al. suggested that plasmin directly induced platelet aggregation via ADP secretion from platelets. In addition, the researchers showed that platelet shape change occurred just after the stimulation with plasmin, while several minutes were required for granule release and aggregation [15]. Interestingly, platelet incubation with lower plasmin concentrations for 5 min at room temperature enhanced platelet aggregation, integrin αIIbβ3 expression, α-, δ-granules, and lysosomes release [16][17]. The data obtained from Quinton et al. indicated that plasmin induced platelet aggregation primarily through cleavage of Protease-Activated Receptors (PAR)-4 [16].
It could be of clinical relevance to investigate the molecular aspects of the regulation of plasmin-mediated platelet activation. More recently, Pielsticker et al. indicated plasmin as a potent platelet activator, inducing P-selectin expression and fibrinogen binding. Moreover, the researchers identified matricellular glycoprotein thrombospondin-1 (TSP-1) as a promoter or an inhibitor of plasmin-induced platelet activation, depending on its concentration, when bound to plasmin [18].
An important factor influencing the platelet response to plasmin in vitro is the platelet environment. Blockmans et al. reported the aggregatory effects of plasmin on gel-filtered platelets but no aggregation response in PRP, probably due to the presence of α2-antiplasmin in PRP [19]. In contrast to these data, Pielsticker et al. observed plasmin activating effects on platelets not only in the absence of plasma factors but also in diluted platelet-rich plasma and citrated whole blood, despite the presence of the plasmatic plasmin inhibitors α2-antiplasmin and α2-macroglobulin [18].
Related to the inhibitory effects of plasmin on platelets, Schafer and Adelman found that plasmin inhibited arachidonic acid mobilization from platelet membrane phospholipid pools [20]. Plasmin treatment of washed platelets resulted in progressive loss of GPIb, which contains receptor sites for von Willebrand (vWF), thereby reducing vWF-mediated platelet agglutination [13]. In the presence of plasma, the incubation of human platelets with streptokinase, able to produce plasmin, resulted in impairment of aggregation [21].
In conclusion, plasmin seems to exert contrasting effects on platelets, being able to both activate and inhibit platelet activity in vitro. This bivalent behavior could be caused by several variables, such as temperature and/or incubation time, that can modify and influence the platelet response to plasmin in vitro, but a consistent body of evidence predominantly indicates that plasmin acts as a platelet activator.

3. Tissue-Type Plasminogen Activator

The potential role for platelets in the modulation of fibrinolysis became apparent when Vaughan et al. demonstrated that the platelet surface possessed for tPA a large number of specific, low-affinity binding sites that were amplified upon thrombin stimulation [22]. However, specific receptors for tPA on the platelet surface have not yet been identified. In addition, the presence of tPA has been detected by different techniques in isolated megakaryocytes, as well as in platelets [23][24].
tPA released from endothelium protects against the formation of platelet aggregates in vivo by modulation of platelet cyclic nucleotides [25].
The thrombolytic activity of tPA was impaired by platelets in vitro as a consequence of clot retraction and decreased binding of the plasminogen activator [26]. This may explain the resistance of platelet-rich clots to lysis in vivo.
Importantly, the “lisability” of platelet-rich areas depends on the complex interrelationships between the mechanical platelet contractile forces and the process of fibrinolysis. In fact, GP IIb/IIIa inhibitors facilitated the rate and the extent of fibrinolysis by improving recombinant tPA binding velocity and, subsequently, the lysis rate in platelet-rich areas, thus providing new insights into the synergistic potential of GP IIb/IIIa inhibitors and fibrinolytic agents in dissolving thrombotic vaso-occlusions [27].
A model of platelet lysate affinity chromatography showed that a number of platelet proteins that have previously been found to inhibit the fibrinolytic system were captured by tPA. Since there is evidence that platelets undergo lysis after trauma, the researchers hypothesized that platelet lysis could shut down tPA-mediated fibrinolysis, with implications for therapeutic intervention, in order to balance fibrinolysis during resuscitation of trauma patients [28].

4. Urokinase Plasminogen Activator

Plasminogen activator uPA plays a central role outside the vasculature by interacting with its receptor uPAR on the cell surface, but several studies reported an active role also in fibrinolysis.
Platelets from normal subjects contain a small amount of uPA (up to 1.3 ng/109), while insignificant levels were found in megakaryocytes [29]. It was shown that about 20% of pro-uPA intrinsic to blood was closely related to platelets and that platelets were able to rapidly incorporate exogenous pro-uPA [30].
pro-uPA seems to be involved in a mechanism for stimulation of fibrinolysis by platelets. In fact, it was observed that pro-uPA could mediate the clot lysis, and this mechanism was enhanced by platelets. Loza JP et al. reported that platelet-bound prekallikrein was able to enhance pro-uPA-induced clot lysis [31], but most probably, platelet-bound plasminogen is the essential player in this phenomenon. In fact, platelets from plasminogen-deficient mice were not able to activate pro-uPA, and the activation of pro-uPA was significantly enhanced by plasminogen on the platelet surface rather than plasminogen in the solution phase [9]. Interestingly, fragment E-2 from fibrin promoted plasminogen activation by pro-uPA, and fibrin specificity to pro-uPA didn’t require its conversion to uPA [32]. Furthermore, in the presence of plasma, activation of Glu-plasminogen bound to degraded fibrin was found to be more efficient with pro-uPA than with uPA [33]. In plasma, the pro-uPA fibrinolytic property was stable for several days and, unlike uPA, did not form stable inhibitor complexes [34]. Altogether, these findings suggest the use of pro-uPA as a thrombolytic agent against platelet-rich thrombi, which are more resistant to lysis.
Storage of large amounts of uPA in blood platelets was observed in a congenital bleeding disorder known as Quebec Platelet Disorder (QPD). Unlike normal platelets, QPD platelets contain approximately 400–600 ng/109 of uPA without increased uPA in plasma or systemic fibrinolysis [35]. uPA from QPD platelets is predominantly detected as active two-chain uPA and in smaller amounts as single-chain and/or forms complexed to PAI-1. The high levels of active uPA were accompanied by abnormal intraplatelet generation of plasmin. During clot formation, uPA released by QPD platelets led to platelet-dependent increased fibrinolysis, thus provoking QPD bleeding. QPD platelets showed the loss of normal α-granule proteins, and this may possibly contribute to QPD bleeding. The genetic defect that causes QPD is characterized by a duplication mutation that selectively induces increased production of normal PLAU transcripts by megakaryocytes [36].
Another mechanism for uPA-mediated plasmin formation has been reported: glu-plasminogen bound to platelet surface was converted to plasmin with a high efficiency by uPA expressed on monocytes or endothelial cells-derived microparticles [10]. Importantly, uPA associated with platelet surface was able to upregulate uPA mRNA synthesis by endothelial cells [37]. Through this mechanism, platelets may control intravascular fibrin deposition.
The connection between platelet functions and plasminogen activator uPA has also been found in angiogenesis. It is known that platelets are an important circulating store of angiogenesis regulators, such as the angiogenesis inhibitor angiostatin. Jurasz et al. showed that angiostatin generation by platelets was inhibited by a selective inhibitor of uPA. The researchers concluded that platelets constitutively generate angiostatin on their membranes, and this mechanism is mediated by uPA [38].

5. High-Affinity uPA Receptor (uPAR)

It has been established that uPA receptor (uPAR) is expressed on the platelet surface, but data on uPAR involvement in platelet pathophysiology are not available. However, a critical role of platelets uPAR for kinetics and endothelium adhesion associated with inflammation has been demonstrated [39]. Sloand et al. reported increased suPAR levels in the sera of patients affected by paroxysmal nocturnal hemoglobinuria (PNH). In PNH patients, GPI-negative granulocytes and platelets were the probable source of elevated plasma suPAR levels that were associated with thrombosis and inhibition of plasmin generation [40].
The cleaved form of uPAR (DII-DIII-uPAR) containing the SRSRY sequence corresponding to amino acids 88–92 at its N-terminus interacts with N-formyl peptide receptors (FPRs), thus mediating cell migration [41]. FPRs belong to a family of G protein-coupled receptors and are involved in the regulation of innate immunity and host defense. Three family members are identified: FPR1, FPR2/ALX, and FPR3, mainly expressed in several types of innate immune cells, including neutrophils and monocytes/macrophages; other cell types also express FPR members. Recently, a group assigned an important pathogenetic role to crosstalk between uPAR and FPRs in inflammation and cancer [41][42]. Despite numerous research focused on the role of FPRs in the modulation of immune responses, little data on their ability to regulate hemostasis and thrombosis are available. Czapiga M et al. demonstrated the expression of FPR1 on the platelet surface and its ability to induce chemotactic and migratory functions upon stimulation with E coli-derived fMLF [43]. Salamah et al. showed the expression of FPR2 and its effects in promoting platelet activation and thrombus formation under arterial flow conditions [44].
Further studies are necessary to establish the role of FPRs on platelets and their contribution to hemostasis and thrombosis, but it would be interesting to investigate whether crosstalk between uPAR and FPRs occurs on the platelet surface and whether it is involved in the regulation of FPRs-mediated effects on platelets.

6. Plasminogen Activator Inhibitors (PAI-1 and PAI-2)

The main endogenous inhibitor of plasminogen activators and the most important modulator of the fibrinolytic system is PAI-1. Several cell types are capable of synthesizing, storing, and releasing PAI-1, but platelets are considered a major reservoir of plasma PAI-1 [45]. However, there is an ongoing scientific debate on the effective contribution of platelet PAI-1 to fibrinolysis.
About 90% of the total PAI-1 in blood derived from platelet α-granules and platelet count were correlated with plasma PAI-1 concentrations [46]. Recent findings showed that more than 50% of platelet PAI-1 is in the active configuration, contrary to preliminary studies where the majority of PAI-1 stored in platelets has been considered to be inactive [47]. Because platelets retain mRNA from megakaryocytes and a capacity for synthesis of some proteins, platelets can de novo synthesize PAI-1, and the amount synthesized in vitro in 24 h is 35-fold higher than required to maintain normal plasma levels. Interestingly, Brogren et al. investigated the hypothesis that platelets might be the source of plasma PAI-1 and that the cellular source of PAI-1 can be determined by its tissue-specific glycosylation pattern [45]. PAI-1 isolated from macrophages, endothelial cells, and adipose tissue expressed heterogeneous glycosylation patterns, but no glycans were detected on PAI-1 isolated from plasma or platelets from healthy individuals, thus suggesting that platelets may be the main source of plasma PAI-1 [48].
The study of platelet PAI-1 provided multiple evidence that it plays a central role in fibrinolytic resistance to clots and thrombi. In vitro studies showed that platelet-mediated fibrinolytic resistance is reduced by neutralizing antibodies direct against PAI-1 [49]. In platelet-rich plasma clot lysis mediated by tPA, the release of PAI-1 from activated platelets resulted in a prolongation of the clot lysis time [50].
In order to elucidate the mechanisms responsible for the stability of platelet-rich thrombi, in vitro model thrombus (composed of thrombin-activated platelets, fibrin, plasminogen, and tPA) provided novel insights into the role of platelet PAI-1. In particular, PAI-1 released from activated platelets stabilizes fibrin deposited on the platelet surface and thus increases the lysis resistance of platelet-rich thrombi [49].
PAI-1 circulates in complex with vitronectin (VN), an interaction that stabilizes PAI-1 in the active form [51]. VN can be internalized into platelet α-granules from plasma, but its effects on the platelet pool of PAI-1 are not clear. Confocal microscopic analysis of platelet-rich plasma clots confirmed the co-localization of PAI-1 with VN and vimentin on the activated platelet surface, suggesting that platelet vimentin may regulate fibrinolysis by binding platelet-derived VN/PAI-1 complexes [52].
Animal model studies established that platelet PAI-1 was primarily involved in arterial thrombi, which contain high platelet content [1]. In particular, Zhu et al. noted that, in a murine model of carotid artery injury, the reperfusion after tPA treatment occurred in PAI-deficient mice but not in wild-type animals, thus demonstrating the main role of PAI-1 in the thrombolytic resistance of platelet-rich thrombi [53].
In line with in vitro studies and data from animal models, the immunohistochemical analysis of human thrombi suggested that active recruitment of platelets contributes to the high PAI-1 concentration in thrombi [54].
Diverse pathological conditions are associated with unregulated PAI-1 levels, but only plasma PAI-1 levels in most cases were examined.
Platelets were capable of immediate degranulation when exposed to thrombin leading to the release of active PAI-1, which is complexed with tPA and inhibits tPA-induced fibrinolysis [55]. Following degranulation, platelets synthesize more PAI-1, but such synthesis occurs over a long period of time, rendering these platelets dysfunctional. Since thrombin levels are elevated in trauma and intensive care unit (ICU) patients, these observations deserve more attention.
Platelet PAI-1 could play a central role in diverse pathological conditions associated with hypoxia, such as chronic obstructive pulmonary disease (COPD). In fact, exposure of human platelets to hypoxia enhanced PAI-1 expression. In addition, circulating platelets isolated from COPD patients had higher PAI-1 levels compared to controls, and probably, the prothrombotic phenotype associated with hypoxia may be attributable to the synthesis of PAI-1 by platelets [56].
It has been proposed that miRNA plays a central role in the regulation of fibrinolysis [57]. Platelets of patients with type 2 mellitus diabetes (DM2) release significantly more PAI-1 at the same level of platelet aggregation. This may contribute to enhanced thrombosis in diabetes [58]. Moreover, recent studies showed that mir-30c negatively regulated PAI-1 mRNA and protein expression in megakaryocytes; hyperglicemia-induced repression of mir-30c enhanced PAI-1 expression and thrombus formation in DM2 [59].
In congenital bleeding disorders, low levels of intraplatelet PAI-1 were found, but it is difficult to establish the relationship between deficiency of platelet PAI-1 and bleeding [1].
A significant increase in platelet PAI-1 levels was observed in essential thrombocythemia (ET) patients with thrombotic complications compared to ET patients without thrombotic complications and control group [60].
Taken together, the evidence strongly suggests that platelet PAI-1 plays a central role in arterial thrombosis and in hemostasis, as it is a determinant factor for fibrinolytic resistance.
PAI-2 is classically considered as an inhibitor of fibrinolysis via inhibition of plasmin generation by uPA and, to a lesser extent, tPA. Novel functions were attributed to PAI-2, which seems to be involved in hemostasis and to be associated with platelets. In particular, PAI-2 deficiency in mice reduced bleeding times via dysregulated platelet activation. The immunohistochemistry analysis of blood clots demonstrated that PAI-2 was associated with platelet aggregates; however, PAI-2 was not detected in human platelets [61].

7. Alpha 2-Antiplasmin

α2-antiplasmin is the principal inhibitor of plasmin and can be detected in platelet α-granules. α2-antiplasmin antigen contained in platelets corresponded to 0.05% of the total α2-antiplasmin present in the blood on a volume basis, and 87.5% of this material can be released when platelets are stimulated by thrombin. Immunohistochemical analysis of human thrombi showed that α2-antiplasmin was present at high concentrations, but platelets released small amounts of α2-antiplasmin [1][54][62]. However, thrombus stabilization against fibrinolysis involves this mechanism: platelet FXIII-A through exposure to the activated platelet membrane exerts antifibrinolytic function by cross-linking α2-antiplasmin to fibrin [63].
Takei M et al. examined the effects of α2-antiplasmin on platelet aggregation using animal models and found that lack of α2-antiplasmin increased platelet micro-aggregation when platelets were stimulated with ADP. Microaggregates produced in the early phase of platelet activation have the potential to aggravate thrombus formation, leading to vascular occlusions by the formation of a platelet-rich thrombus [64].

References

  1. Colucci, M.; Semeraro, N.; Semeraro, F. Platelets and Fibrinolysis. In Platelets in Thrombotic and Non-Thrombotic Disorders; Gresele, P., Kleiman, N., Lopez, J., Page, C., Eds.; Springer: Cham, Switzerland, 2017.
  2. Coppinger, J.A.; Cagney, G.; Toomey, S.; Kislinger, T.; Belton, O.; McRedmond, J.P.; Cahill, D.J.; Emili, A.; Fitzgerald, D.J.; Maguire, P.B. Characterization of the proteins released from activated platelets leads to localization of novel platelet proteins in human atherosclerotic lesions. Blood 2004, 103, 2096–2104.
  3. Whyte, C.S.; Mitchell, J.L.; Mutch, N.J. Platelet-Mediated Modulation of Fibrinolysis. Semin. Thromb. Hemost. 2017, 43, 115–128.
  4. Veljkovic, D.K.; Rivard, G.E.; Diamandis, M.; Blavignac, J.; Cramer-Bordé, E.M.; Hayward, C.P. Increased expression of urokinase plasminogen activator in Quebec platelet disorder is linked to megakaryocyte differentiation. Blood 2009, 113, 1535–1542.
  5. Miles, L.A.; Plow, E.F. Binding and activation of plasminogen on the platelet surface. J. Biol. Chem. 1985, 260, 4303–4311.
  6. Miles, L.A.; Dahlberg, C.M.; Plow, E.F. The cell-binding domains of plasminogen and their function in plasma. J. Biol. Chem. 1988, 263, 11928–11934.
  7. Adelman, B.; Rizk, A.; Hanners, E. Plasminogen interactions with platelets in plasma. Blood 1988, 5, 1530–1535.
  8. Loscalzo, J.; Pasche, B.; Ouimet, H.; Freedman, J.E. Platelets and plasminogen activation. Thromb Haemost 1995, 74, 291–293.
  9. Baeten, K.M.; Richard, M.C.; Kanse, S.M.; Mutch, N.J.; Degen, J.L.; Booth, N.A. Activation of single-chain urokinase-type plasminogen activator by platelet-associated plasminogen: A mechanism for stimulation of fibrinolysis by platelets. J. Thromb. Haemost. 2010, 8, 1313–1322.
  10. Dejouvencel, T.; Doeuvre, L.; Lacroix, R.; Plawinski, L.; Dignat-George, F.; Lijnen, H.R.; Anglés-Cano, E. Fibrinolytic cross-talk: A new mechanism for plasmin formation. Blood 2010, 115, 2048–2056.
  11. Whyte, C.S.; Swieringa, F.; Mastenbroek, T.G.; Lionikiene, A.S.; Lancé, M.D.; van der Meijden, P.E.J.; Heemskerk, J.W.M.; Mutch, N.J. Plasminogen associates with phosphatidylserine-exposing platelets and contributes to thrombus lysis under flow. Blood 2015, 125, 2568–2578.
  12. Whyte, C.S.; Morrow, G.B.; Baik, N.; Booth, N.A.; Jalal, M.M.; Parmer, R.J.; Miles, L.A.; Mutch, N.J. Exposure of plasminogen and a novel plasminogen receptor, Plg-RKT, on activated human and murine platelets. Blood 2021, 137, 248–257.
  13. Van der Vorm, L.N.; Remijn, J.A.; de Laat, B.; Huskens, D. Effects of Plasmin on von Willebrand Factor and Platelets: A Narrative Review. TH Open 2018, 2, e218–e228.
  14. Niewiarowski, S.; Senyi, A.F.; Gillies, P. Plasmin-induced platelet aggregation and platelet release reaction. Effects on hemostasis. J. Clin. Investig. 1973, 52, 1647–1659.
  15. Ishii-Watabe, A.; Uchida, E.; Mizuguchi, H.; Hayakawa, T. On the mechanism of plasmin-induced platelet aggregation. Implications of the dual role of granule ADP. Biochem. Pharm. 2000, 59, 1345–1355.
  16. Quinton, T.M.; Kim, S.; Derian, C.K.; Jin, J.; Kunapuli, S.P. Plasmin-mediated activation of platelets occurs by cleavage of protease-activated receptor 4. J. Biol. Chem. 2004, 279, 18434–18439.
  17. Shigeta, O.; Kojima, H.; Jikuya, T.; Terada, Y.; Atsumi, N.; Sakakibara, Y.; Nagasawa, T.; Mitsui, T. Aprotinin inhibits plasmin-induced platelet activation during cardiopulmonary bypass. Circulation 1997, 96, 569–574.
  18. Pielsticker, C.; Brodde, M.F.; Raum, L.; Jurk, K.; Kehrel, B.E. Plasmin-Induced Activation of Human Platelets Is Modulated by Thrombospondin-1, Bona Fide Misfolded Proteins and Thiol Isomerases. Int J. Mol. Sci. 2020, 21, 8851.
  19. Blockmans, D.; Deckmyn, H.; Hove, L.V.; Vermylen, J. The effect of plasmin on platelet function. Platelets 1996, 7, 139–148.
  20. Schafer, A.I.; Adelman, B. Plasmin inhibition of platelet function and of arachidonic acid metabolism. J. Clin. Invest. 1985, 75, 456–461.
  21. Gouin, I.; Lecompte, T.; Morel, M.C.; Lebrazi, J.; Modderman, P.W.; Kaplan, C.; Samama, M.M. In vitro effect of plasmin on human platelet function in plasma. Inhibition of aggregation caused by fibrinogenolysis. Circulation 1992, 85, 935–941.
  22. Vaughan, D.E.; Mendelsohn, M.E.; Declerck, P.J.; Van Houtte, E.; Collen, D.; Loscalzo, J. Characterization of the binding of human tissue-type plasminogen activator to platelets. J. Biol. Chem. 1989, 264, 15869–15874.
  23. Brisson-Jeanneau, C.; Nelles, L.; Rouer, E.; Sultan, Y.; Benarous, R. Tissue-plasminogen activator RNA detected in megakaryocytes by in situ hybridization and biotinylated probe. Histochemistry 1990, 95, 23–26.
  24. Wang, D.L.; Pan, Y.T.; Wang, J.J.; Cheng, C.H.; Liu, C.Y. Demonstration of a functionally active tPA-like plasminogen activator in human platelets. Thromb. Haemost. 1994, 71, 493–498.
  25. Stamler, J.S.; Simon, D.I.; Jaraki, O.; Osborne, J.A.; Francis, S.; Mullins, M.; Singel, D.; Loscalzo, J. S-nitrosylation of tissue-type plasminogen activator confers vasodilatory and antiplatelet properties on the enzyme. Proc. Natl. Acad. Sci. USA 1992, 89, 8087–8091.
  26. Kunitada, S.; FitzGerald, G.A.; Fitzgerald, D.J. Inhibition of clot lysis and decreased binding of tissue-type plasminogen activator as a consequence of clot retraction. Blood 1992, 79, 1420–1427.
  27. Collet, J.P.; Montalescot, G.; Lesty, C.; Weisel, J.W. A structural and dynamic investigation of the facilitating effect of glycoprotein IIb/IIIa inhibitors in dissolving platelet-rich clots. Circ. Res. 2002, 90, 428–434.
  28. Moore, H.B.; Moore, E.E.; Gonzalez, E.; Hansen, K.C.; Dzieciatkowska, M.; Chapman, M.P.; Sauaia, A.; West, B.; Banerjee, A.; Silliman, C.C. Hemolysis exacerbates hyperfibrinolysis, whereas platelolysis shuts down fibrinolysis: Evolving concepts of the spectrum of fibrinolysis in response to severe injury. Shock 2015, 43, 39–46.
  29. Diamandis, M.; Veljkovic, D.K.; Maurer-Spurej, E.; Rivard, G.E.; Hayward, C.P. Quebec platelet disorder: Features, pathogenesis and treatment. Blood Coagul. Fibrinolysis 2008, 19, 109–119.
  30. Gurewich, V.; Johnstone, M.; Loza, J.P.; Pannell, R. Pro-urokinase and prekallikrein are both associated with platelets. Implications for the intrinsic pathway of fibrinolysis and for therapeutic thrombolysis. FEBS Lett. 1993, 318, 317–321.
  31. Loza, J.P.; Gurewich, V.; Johnstone, M.; Pannell, R. Platelet-bound prekallikrein promotes pro-urokinase-induced clot lysis: A mechanism for targeting the factor XII dependent intrinsic pathway of fibrinolysis. Thromb. Haemost. 1994, 71, 347–352.
  32. Liu, J.N.; Gurewich, V. Fragment E-2 from fibrin substantially enhances pro-urokinase-induced Glu-plasminogen activation. A kinetic study using the plasmin-resistant mutant pro-urokinase Ala-158-rpro-UK. Biochemistry 1992, 31, 6311–6317.
  33. Fleury, V.; Lijnen, H.R.; Anglés-Cano, E. Mechanism of the enhanced intrinsic activity of single-chain urokinase-type plasminogen activator during ongoing fibrinolysis. J. Biol. Chem. 1993, 268, 18554–18559.
  34. Pannell, R.; Gurewich, V. Pro-urokinase: A study of its stability in plasma and of a mechanism for its selective fibrinolytic effect. Blood 1986, 67, 1215–1223.
  35. Kahr, W.H.; Zheng, S.; Sheth, P.M.; Pai, M.; Cowie, A.; Bouchard, M.; Podor, T.J.; Rivard, G.E.; Hayward, C.P. Platelets from patients with the Quebec platelet disorder contain and secrete abnormal amounts of urokinase-type plasminogen activator. Blood 2001, 98, 257–265.
  36. Hayward, C.P.M.; Liang, M.; Tasneem, S.; Soomro, A.; Waye, J.S.; Paterson, A.D.; Rivard, G.E.; Wilson, M.D. The duplication mutation of Quebec platelet disorder dysregulates PLAU, but not C10orf55, selectively increasing production of normal PLAU transcripts by megakaryocytes but not granulocytes. PLoS ONE 2017, 12, e0173991.
  37. Camoin-Jau, L.; Pannell, R.; Anfosso, F.; Bardin, N.; Sabatier, F.; Sampol, J.; Gurewich, V.; Dignat-George, F. Platelet associated u-PA up-regulates u-PA synthesis by endothelial cells. Thromb. Haemost. 2002, 88, 517–523.
  38. Jurasz, P.; Santos-Martinez, M.J.; Radomska, A.; Radomski, M.W. Generation of platelet angiostatin mediated by urokinase plasminogen activator: Effects on angiogenesis. J. Thromb. Haemost. 2006, 4, 1095–1106.
  39. Piguet, P.F.; Vesin, C.; Donati, Y.; Tacchini-Cottier, F.; Belin, D.; Barazzone, C. Urokinase receptor (uPAR, CD87) is a platelet receptor important for kinetics and TNF-induced endothelial adhesion in mice. Circulation 1999, 99, 3315–3321.
  40. Sloand, E.M.; Pfannes, L.; Scheinberg, P.; More, K.; Wu, C.O.; Horne, M.; Young, N.S. Increased soluble urokinase plasminogen activator receptor (suPAR) is associated with thrombosis and inhibition of plasmin generation in paroxysmal nocturnal hemoglobinuria (PNH) patients. Exp. Hematol. 2008, 36, 1616–1624.
  41. Rossi, F.W.; Napolitano, F.; Pesapane, A.; Mascolo, M.; Staibano, S.; Matucci-Cerinic, M.; Guiducci, S.; Ragno, P.; di Spigna, G.; Postiglione, L.; et al. Upregulation of the N-formyl Peptide receptors in scleroderma fibroblasts fosters the switch to myofibroblasts. J. Immunol 2015, 194, 5161–5173.
  42. Napolitano, F.; Rossi, F.W.; Pesapane, A.; Varricchio, S.; Ilardi, G.; Mascolo, M.; Staibano, S.; Lavecchia, A.; Ragno, P.; Selleri, C.; et al. N-Formyl Peptide Receptors Induce Radical Oxygen Production in Fibroblasts Derived From Systemic Sclerosis by Interacting With a Cleaved Form of Urokinase Receptor. Front. Immunol. 2018, 9, 574.
  43. Czapiga, M.; Gao, J.L.; Kirk, A.; Lekstrom-Himes, J. Human platelets exhibit chemotaxis using functional N-formyl peptide receptors. Exp. Hematol. 2005, 33, 73–84.
  44. Salamah, M.F.; Ravishankar, D.; Kodji, X.; Moraes, L.A.; Williams, H.F.; Vallance, T.M.; Albadawi, D.A.; Vaiyapuri, R.; Watson, K.; Gibbins, J.M.; et al. The endogenous antimicrobial cathelicidin LL37 induces platelet activation and augments thrombus formation. Blood Adv. 2018, 2, 2973–2985.
  45. Brogren, H.; Karlsson, L.; Andersson, M.; Wang, L.; Erlinge, D.; Jern, S. Platelets synthesize large amounts of active plasminogen activator inhibitor 1. Blood 2004, 104, 3943–3948.
  46. Birdane, A.; Haznedaroglu, I.C.; Bavbek, N.; Kosar, A.; Buyukasik, Y.; Ozcebe, O.; Dündar, S.V.; Kirazli, S. The plasma levels of prostanoids and plasminogen activator inhibitor-1 in primary and secondary thrombocytosis. Clin. Appl. Thromb. Hemost. 2005, 11, 197–201.
  47. Brogren, H.; Wallmark, K.; Deinum, J.; Karlsson, L.; Jern, S. Platelets retain high levels of active plasminogen activator inhibitor 1. PLoS ONE 2011, 6, e26762.
  48. Brogren, H.; Sihlbom, C.; Wallmark, K.; Lönn, M.; Deinum, J.; Karlsson, L.; Jern, S. Heterogeneous glycosylation patterns of human PAI-1 may reveal its cellular origin. Thromb. Res. 2008, 122, 271–281.
  49. Braaten, J.V.; Handt, S.; Jerome, W.G.; Kirkpatrick, J.; Lewis, J.C.; Hantgan, R.R. Regulation of fibrinolysis by platelet-released plasminogen activator inhibitor 1: Light scattering and ultrastructural examination of lysis of a model platelet-fibrin thrombus. Blood 1993, 81, 1290–1299.
  50. Serizawa, K.; Urano, T.; Kozima, Y.; Takada, Y.; Takada, A. The potential role of platelet PAl-1 in t-PA mediated clot lysis of platelet rich plasma. Thromb. Res. 1993, 71, 289–300.
  51. Wiman, B. Plasminogen activator inhibitor 1 (PAI-1) in plasma: Its role in thrombotic disease. Thromb. Haemost. 1995, 74, 71–76.
  52. Podor, T.J.; Singh, D.; Chindemi, P.; Foulon, D.M.; McKelvie, R.; Weitz, J.I.; Austin, R.; Boudreau, G.; Davies, R. Vimentin exposed on activated platelets and platelet microparticles localizes vitronectin and plasminogen activator inhibitor complexes on their surface. J. Biol. Chem. 2002, 277, 7529–7539.
  53. Zhu, Y.; Carmeliet, P.; Fay, W.P. Plasminogen activator inhibitor-1 is a major determinant of arterial thrombolysis resistance. Circulation 1999, 99, 3050–3055.
  54. Robbie, L.A.; Bennett, B.; Croll, A.M.; Brown, P.A.; Booth, N.A. Proteins of the fibrinolytic system in human thrombi. Thromb. Haemost. 1996, 75, 127–133.
  55. Huebner, B.R.; Moore, E.E.; Moore, H.B.; Stettler, G.R.; Nunns, G.R.; Lawson, P.; Sauaia, A.; Kelher, M.; Banerjee, A.; Silliman, C.C. Thrombin Provokes Degranulation of Platelet α-Granules Leading to the Release of Active Plasminogen Activator Inhibitor-1 (PAI-1). Shock 2018, 50, 671–676.
  56. Chaurasia, S.N.; Kushwaha, G.; Kulkarni, P.P.; Mallick, R.L.; Latheef, N.A.; Mishra, J.K.; Dash, D. Platelet HIF-2α promotes thrombogenicity through PAI-1 synthesis and extracellular vesicle release. Haematologica 2019, 104, 2482–2492.
  57. Alfano, D.; Gorrasi, A.; Li Santi, A.; Ricci, P.; Montuori, N.; Selleri, C.; Ragno, P. Urokinase receptor and CXCR4 are regulated by common microRNAs in leukaemia cells. J. Cell Mol. Med. 2015, 19, 2262–2272.
  58. Jokl, R.; Klein, R.L.; Lopes-Virella, M.F.; Colwell, J.A. Release of platelet plasminogen activator inhibitor 1 in whole blood is increased in patients with type II diabetes. Diabetes Care 1995, 18, 1150–1155.
  59. Luo, M.; Li, R.; Ren, M.; Chen, N.; Deng, X.; Tan, X.; Li, Y.; Zeng, M.; Yang, Y.; Wan, Q.; et al. Hyperglycaemia-induced reciprocal changes in miR-30c and PAI-1 expression in platelets. Sci Rep. 2016, 6, 36687.
  60. Bazzan, M.; Tamponi, G.; Gallo, E.; Stella, S.; Schinco, P.C.; Pannocchia, A.; Pileri, A. Fibrinolytic imbalance in essential thrombocythemia: Role of platelets. Haemostasis 1993, 23, 38–44.
  61. Schroder, W.A.; Le, T.T.; Gardner, J.; Andrews, R.K.; Gardiner, E.E.; Callaway, L.; Suhrbier, A. SerpinB2 deficiency in mice reduces bleeding times via dysregulated platelet activation. Platelets 2019, 30, 658–663.
  62. Plow, E.F.; Miles, L.A.; Collen, D. Platelet alpha 2-antiplasmin. Methods Enzymol. 1989, 169, 296–300.
  63. Mitchell, J.L.; Lionikiene, A.S.; Fraser, S.R.; Whyte, C.S.; Booth, N.A.; Mutch, N.J. Functional factor XIII-A is exposed on the stimulated platelet surface. Blood 2014, 124, 3982–3990.
  64. Takei, M.; Matsuno, H.; Okada, K.; Ueshima, S.; Matsuo, O.; Kozawa, O. Lack of alpha 2-antiplasmin enhances ADP induced platelet micro-aggregation through the presence of excess active plasmin in mice. J. Thromb. Thrombolysis 2002, 14, 205–211.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Video Production Service
Feedback