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Zhang B, Ding J, Ma Z. ICP4-Associated Activation of Rap1b Facilitates Herpes Simplex Virus Type I (HSV-1) Infection in Human Corneal Epithelial Cells. Viruses 2023; 15:1457. [PMID: 37515145 PMCID: PMC10385634 DOI: 10.3390/v15071457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/25/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
The strong contribution of RAS-related protein 1b (Rap1b) to cytoskeleton remodeling determines intracellular and extracellular physiological activities, including the successful infection of viruses in permissive cells, but its role in the HSV-1 life cycle is still unclear. Here, we demonstrated that the HSV-1 immediate early (IE) gene ICP4 inhibits protein kinase A (PKA) phosphorylation to induce Rap1b-activation-mediated viral infection. Rap1b activation and membrane enrichment begin at the early stage of HSV-1 infection and remain active during the proliferation period of the virus. Treating the cells with Rap1b small interfering RNA (siRNA) showed a dose-dependent decrease in viral infection levels, but no dose-dependent increase was observed after Rap1b overexpression. Further investigation indicated that the suppression of Rap1b activation derives from phosphorylated PKA and Rap1b mutants with partial or complete prenylation instead of phosphorylation, which promoted viral infection in a dose-dependent manner. Furthermore, the PKA agonist Forskolin disturbed Rap1b activation in a dose-dependent manner, accompanied by a decreasing trend in viral infection. Moreover, the HSV-1 IE gene ICP4 induced PKA dephosphorylation, leading to continuous Rap1b activation, followed by cytoskeleton rearrangement induced by cell division control protein 42 (CDC42) and Ras-related C3 botulinum toxin substrate 1 (RAC1). These further stimulated membrane-triggered physiological processes favoring virus infection. Altogether, we show the significance of Rap1b during HSV-1 infection and uncover the viral infection mechanism determined by the posttranslational regulation of the viral ICP4 gene and Rap1b host protein.
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Affiliation(s)
- Beibei Zhang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
| | - Juntao Ding
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
| | - Zhenghai Ma
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
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Abstract
INTRODUCTION Platelets play a key role in arterial thrombosis and antiplatelet therapy is pivotal in the treatment of cardiovascular disease. Current antiplatelet drugs target different pathways of platelet activation and show specific pharmacodynamic and pharmacokinetic characteristics, implicating clinically relevant drug-drug interactions. AREAS COVERED This article reviews the role of platelets in hemostasis and cardiovascular thrombosis, and discusses the key pharmacodynamics, drug-drug interactions and reversal strategies of clinically used antiplatelet drugs. EXPERT OPINION Antiplatelet therapies target distinct pathways of platelet activation: thromboxane A2 synthesis, adenosine diphosphate-mediated signaling, integrin αIIbβ3 (GPIIb/IIIa), thrombin-mediated platelet activation via the PAR1 receptor and phosphodiesterases. Key clinical drug-drug interactions of antiplatelet agents involve acetylsalicylic acid - ibuprofen, clopidogrel - omeprazole, and morphine - oral P2Y12 inhibitors, all of which lead to an attenuated antiplatelet effect. Platelet function and genetic testing and the use of scores (ARC-HBR, PRECISE-DAPT, ESC ischemic risk definition) may contribute to a more tailored antiplatelet therapy. High on-treatment platelet reactivity presents a key problem in the acute management of ST-elevation myocardial infarction (STEMI). A treatment strategy involving early initiation of an intravenous antiplatelet agent may be able to bridge the gap of insufficient platelet inhibition in high ischemic risk patients with STEMI.
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Affiliation(s)
- Georg Gelbenegger
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Bernd Jilma
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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Zhou P, Yin JX, Tao HL, Zhang HW. Pathogenesis and management of heparin-induced thrombocytopenia and thrombosis. Clin Chim Acta 2020; 504:73-80. [DOI: 10.1016/j.cca.2020.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 01/30/2020] [Accepted: 02/03/2020] [Indexed: 01/19/2023]
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Kamiyama M, Shirai T, Tamura S, Suzuki-Inoue K, Ehata S, Takahashi K, Miyazono K, Hayakawa Y, Sato T, Takeda K, Naguro I, Ichijo H. ASK1 facilitates tumor metastasis through phosphorylation of an ADP receptor P2Y 12 in platelets. Cell Death Differ 2017; 24:2066-2076. [PMID: 28753204 DOI: 10.1038/cdd.2017.114] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 05/29/2017] [Accepted: 06/08/2017] [Indexed: 12/12/2022] Open
Abstract
Tumor metastasis is the major cause of deaths in cancer patients and is modulated by intertwined stress-responsive signaling cascades. Here we demonstrate that deletion of stress-responsive apoptosis signal-regulating kinase 1 (Ask1) in platelets results in unstable hemostasis and drastic attenuation of tumor lung metastasis, both of which are attributable to platelet dysfunction. Platelet-specific deletion of Ask1 in mice leads to defects in ADP-dependent platelet aggregation, unstable hemostasis and subsequent attenuation of tumor metastasis. We also revealed that activating phosphorylation of Akt is attenuated in Ask1-deficient platelets, contrary to the previous reports suggesting that Akt is negatively regulated by ASK1. Mechanistically, ASK1-JNK/p38 axis phosphorylates an ADP receptor P2Y12 at Thr345, which is required for the ADP-dependent sustained Akt activity that is vital to normal platelet functions. Our findings offer insight into positive regulation of Akt signaling through P2Y12 phosphorylation as well as MAPK signaling in platelets by ASK1 and suggest that ASK1-JNK/p38 axis provides a new therapeutic opportunity for tumor metastasis.
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Affiliation(s)
- Miki Kamiyama
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Toshiaki Shirai
- Department of Clinical and Laboratory Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - Shogo Tamura
- Department of Clinical and Laboratory Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - Katsue Suzuki-Inoue
- Department of Clinical and Laboratory Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - Shogo Ehata
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kei Takahashi
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kohei Miyazono
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yoshihiro Hayakawa
- Division of Pathogenic Biochemistry, Institute of Natural Medicine, University of Toyama, 2630 Suginoki, Toyama 930-0194, Japan
| | - Takehiro Sato
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kohsuke Takeda
- Division of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Isao Naguro
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hidenori Ichijo
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Edelstein LC, Simon LM, Lindsay CR, Kong X, Teruel-Montoya R, Tourdot BE, Chen ES, Ma L, Coughlin S, Nieman M, Holinstat M, Shaw CA, Bray PF. Common variants in the human platelet PAR4 thrombin receptor alter platelet function and differ by race. Blood 2014; 124:3450-8. [PMID: 25293779 PMCID: PMC4246040 DOI: 10.1182/blood-2014-04-572479] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 09/22/2014] [Indexed: 01/22/2023] Open
Abstract
Human platelets express 2 thrombin receptors: protease-activated receptor (PAR)-1 and PAR4. Recently, we reported 3.7-fold increased PAR4-mediated aggregation kinetics in platelets from black subjects compared with white subjects. We now show that platelets from blacks (n = 70) express 14% more PAR4 protein than those from whites (n = 84), but this difference is not associated with platelet PAR4 function. Quantitative trait locus analysis identified 3 common single nucleotide polymorphisms in the PAR4 gene (F2RL3) associated with PAR4-induced platelet aggregation. Among these single nucleotide polymorphisms, rs773902 determines whether residue 120 in transmembrane domain 2 is an alanine (Ala) or threonine (Thr). Compared with the Ala120 variant, Thr120 was more common in black subjects than in white subjects (63% vs 19%), was associated with higher PAR4-induced human platelet aggregation and Ca2+ flux, and generated greater inositol 1,4,5-triphosphate in transfected cells. A second, less frequent F2RL3 variant, Phe296Val, was only observed in blacks and abolished the enhanced PAR4-induced platelet aggregation and 1,4,5-triphosphate generation associated with PAR4-Thr120. PAR4 genotype did not affect vorapaxar inhibition of platelet PAR1 function, but a strong pharmacogenetic effect was observed with the PAR4-specific antagonist YD-3 [1-benzyl-3(ethoxycarbonylphenyl)-indazole]. These findings may have an important pharmacogenetic effect on the development of new PAR antagonists.
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Affiliation(s)
- Leonard C Edelstein
- Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Philadelphia, PA
| | - Lukas M Simon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Cory R Lindsay
- Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Philadelphia, PA
| | - Xianguo Kong
- Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Philadelphia, PA
| | - Raúl Teruel-Montoya
- Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Philadelphia, PA
| | - Benjamin E Tourdot
- Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Philadelphia, PA
| | - Edward S Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Lin Ma
- Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Philadelphia, PA
| | - Shaun Coughlin
- Cardiovascular Research Institute, University of California, San Francisco, CA
| | - Marvin Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH; and
| | - Michael Holinstat
- Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Philadelphia, PA
| | - Chad A Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX; Department of Statistics, Rice University, Houston, TX
| | - Paul F Bray
- Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Philadelphia, PA
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Alberelli MA, De Candia E. Functional role of protease activated receptors in vascular biology. Vascul Pharmacol 2014; 62:72-81. [PMID: 24924409 DOI: 10.1016/j.vph.2014.06.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/30/2014] [Accepted: 06/01/2014] [Indexed: 01/22/2023]
Abstract
Protease activated receptors (PARs) are a small family of G protein-coupled receptors (GPCR) mediating the cellular effects of some proteases of the coagulation system, such as thrombin, or other proteases, such as trypsin or metalloproteinase 1. As the prototype of PARs, PAR1 is a seven transmembrane GPCR that, upon cleavage by thrombin, unmasks a new amino-terminus able to bind intramolecularly to PAR1 itself thus inducing signaling. In the vascular system, thrombin and other proteases of the coagulation-fibrinolysis system, such as plasmin, factor VIIa and factor Xa, activated protein C, are considered physiologically relevant agonists, and PARs appear to largely account for the cellular effects of these enzymes. In the vasculature, PARs are expressed on platelets, endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). In the vessel wall, under physiological conditions, PARs are mainly expressed in ECs and participate in the regulation of vascular tone, by inducing endothelium-dependent relaxation. PAR activation on ECs promotes conversion of these cells into a proinflammatory phenotype, causes increase of vascular permeability, and the exposure/secretion of proteins and cytokines mediating the local accumulation of platelets and leukocytes. These effects contribute to the vascular consequences of sepsis and of diseases such as acute lung injury and acute respiratory distress syndrome. In normal arteries PARs are to a much lesser amount expressed on VSMCs. However, in conditions associated with endothelial dysfunction, PARs mediate contraction, proliferation, migration, hypertrophy of VSMCs and their production of extracellular matrix, thereby contributing to the pathophysiology of atherosclerosis and hypertension. Inhibition of protease-PAR interaction might thus become a potential therapeutic target in various vascular diseases.
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Affiliation(s)
- Maria Adele Alberelli
- Hemostasis and Thrombosis Unit, Department of Internal Medicine, Agostino Gemelli Hospital School of Medicine, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Erica De Candia
- Hemostasis and Thrombosis Unit, Department of Internal Medicine, Agostino Gemelli Hospital School of Medicine, Università Cattolica del Sacro Cuore, Rome, Italy.
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Cho JR, Rollini F, Franchi F, Ferrante E, Angiolillo DJ. Unmet needs in the management of acute myocardial infarction: role of novel protease-activated receptor-1 antagonist vorapaxar. Vasc Health Risk Manag 2014; 10:177-88. [PMID: 24729713 PMCID: PMC3979798 DOI: 10.2147/vhrm.s36045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Platelet activation with subsequent aggregation is a complex process leading to thrombus formation, which remains a key component for atherothrombotic manifestations, in particular myocardial infarction. Therefore, antiplatelet therapies are pivotal for the treatment of these patients. Current oral antiplatelet therapies used for secondary prevention of ischemic recurrences include aspirin and adenosine diphosphate P2Y12 platelet-receptor antagonists. However, despite these therapies, patients who have experienced a myocardial infarction remain at risk for ischemic recurrences. Therefore, more aggressive secondary prevention measures have been an area of research, including identifying additional targets modulating platelet-activation and -aggregation processes. Among these, thrombin-mediated platelet activation via protease-activated receptors (PARs) has been subject to extensive clinical investigation. Several PAR-1 receptor antagonists have been developed. However, vorapaxar is the only one that has completed large-scale clinical investigation. The present manuscript will provide an overview on the role of thrombin-mediated signaling, the impact of PAR-1 blockade with vorapaxar on ischemic and bleeding outcomes, and the potential role for vorapaxar in clinical practice.
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Affiliation(s)
- Jung Rae Cho
- University of Florida College of Medicine – Jacksonville, Jacksonville, FL, USA
| | - Fabiana Rollini
- University of Florida College of Medicine – Jacksonville, Jacksonville, FL, USA
| | - Francesco Franchi
- University of Florida College of Medicine – Jacksonville, Jacksonville, FL, USA
| | - Elisabetta Ferrante
- University of Florida College of Medicine – Jacksonville, Jacksonville, FL, USA
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Racial differences in human platelet PAR4 reactivity reflect expression of PCTP and miR-376c. Nat Med 2013; 19:1609-16. [PMID: 24216752 PMCID: PMC3855898 DOI: 10.1038/nm.3385] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 09/20/2013] [Indexed: 12/17/2022]
Abstract
Racial differences in the pathophysiology of atherothrombosis are poorly understood. We explored the function and transcriptome of platelets in healthy black (n = 70) and white (n = 84) subjects. PAR4 thrombin receptor induced platelet aggregation and calcium mobilization were significantly greater in black subjects. Numerous differentially expressed (DE) RNAs were associated with both race and PAR4 reactivity, including phosphatidylcholine transfer protein (PCTP), and platelets from blacks expressed higher levels of PC-TP protein. PC-TP inhibition or depletion blocked activation of platelets or megakaryocytic cell lines through PAR4 but not PAR1. MiR-376c levels were DE by race and PAR4 reactivity, and were inversely correlated with PCTP mRNA levels, PC-TP protein levels and PAR4 reactivity. MiR-376c regulated expression of PC-TP in human megakaryocytes. A disproportionately high number of miRNAs DE by race and PAR4 reactivity, including miR-376c, are encoded in the DLK1-DIO3 locus, and were lower in platelets from blacks. These results support PC-TP as a regulator of the racial difference in PAR4-mediated platelet activation, indicate a genomic contribution to platelet function that differs by race, and emphasize a need to consider race effects when developing anti-thrombotic drugs.
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The P2Y(12) antagonists, 2MeSAMP and cangrelor, inhibit platelet activation through P2Y(12)/G(i)-dependent mechanism. PLoS One 2012; 7:e51037. [PMID: 23236426 PMCID: PMC3516503 DOI: 10.1371/journal.pone.0051037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 10/29/2012] [Indexed: 11/19/2022] Open
Abstract
Background ADP is an important physiological agonist that induces integrin activation and platelet aggregation through its receptors P2Y1 (Gαq-coupled) and P2Y12 (Gαi-coupled). P2Y12 plays a critical role in platelet activation and thrombosis. Adenosine-based P2Y12 antagonists, 2-methylthioadenosine 5′-monophosphate triethylammonium salt hydrate (2MeSAMP) and Cangrelor (AR-C69931MX) have been widely used to demonstrate the role of P2Y12 in platelet function. Cangrelor is being evaluated in clinical trials of thrombotic diseases. However, a recent study reported that both 2MeSAMP and Cangrelor raise intra-platelet cAMP levels and inhibit platelet aggregation through a P2Y12-independent mechanism. Methodology/Principal Findings The present work, using P2Y12 deficient mice, sought to clarify previous conflicting reports and to elucidate the mechanisms by which 2MeSAMP and Cangrelor inhibit platelet activation and thrombosis. 2MeSAMP and Cangrelor inhibited aggregation and ATP release of wild-type but not P2Y12 deficient platelets. 2MeSAMP and Cangrelor neither raised intracellular cAMP concentrations nor induced phosphorylation of vasodilator-stimulated phosphoprotein (VASP) in washed human or mouse platelets. Furthermore, unlike the activators (PGI2 and forskolin) of the cAMP pathway, 2MeSAMP and Cangrelor failed to inhibit Ca2+ mobilization, Akt phosphorylation, and Rap1b activation in P2Y12 deficient platelets. Importantly, while injection of Cangrelor inhibited thrombus formation in a FeCl3-induced thrombosis model in wild-type mice, it failed to affect thrombus formation in P2Y12 deficient mice. Conclusions These data together demonstrate that 2MeSAMP and Cangrelor inhibit platelet function through the P2Y12-dependent mechanism both in vitro and in vivo.
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Impaired thrombin-induced platelet activation and thrombus formation in mice lacking the Ca(2+)-dependent tyrosine kinase Pyk2. Blood 2012; 121:648-57. [PMID: 23175689 DOI: 10.1182/blood-2012-06-438762] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the present study, we used a knockout murine model to analyze the contribution of the Ca(2+)-dependent focal adhesion kinase Pyk2 in platelet activation and thrombus formation in vivo. We found that Pyk2-knockout mice had a tail bleeding time that was slightly increased compared with their wild-type littermates. Moreover, in an in vivo model of femoral artery thrombosis, the time to arterial occlusion was significantly prolonged in mice lacking Pyk2. Pyk2-deficient mice were also significantly protected from collagen plus epinephrine-induced pulmonary thromboembolism. Ex vivo aggregation of Pyk2-deficient platelets was normal on stimulation of glycoprotein VI, but was significantly reduced in response to PAR4-activating peptide, low doses of thrombin, or U46619. Defective platelet aggregation was accompanied by impaired inside-out activation of integrin α(IIb)β(3) and fibrinogen binding. Granule secretion was only slightly reduced in the absence of Pyk2, whereas a marked inhibition of thrombin-induced thromboxane A(2) production was observed, which was found to be responsible for the defective aggregation. Moreover, we have demonstrated that Pyk2 is implicated in the signaling pathway for cPLA(2) phosphorylation through p38 MAPK. The results of the present study show the importance of the focal adhesion kinase Pyk2 downstream of G-protein-coupled receptors in supporting platelet aggregation and thrombus formation.
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Valgimigli M, Tebaldi M, Campo G, Gambetti S, Bristot L, Monti M, Parrinello G, Ferrari R. Prasugrel versus tirofiban bolus with or without short post-bolus infusion with or without concomitant prasugrel administration in patients with myocardial infarction undergoing coronary stenting: the FABOLUS PRO (Facilitation through Aggrastat By drOpping or shortening Infusion Line in patients with ST-segment elevation myocardial infarction compared to or on top of PRasugrel given at loading dOse) trial. JACC Cardiovasc Interv 2012; 5:268-77. [PMID: 22440491 DOI: 10.1016/j.jcin.2012.01.006] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Revised: 01/09/2012] [Accepted: 01/11/2012] [Indexed: 12/24/2022]
Abstract
OBJECTIVES The authors sought to compare the effect on inhibition of platelet aggregation (IPA) of prasugrel therapy versus tirofiban bolus with or without a post-bolus short drug infusion in ST-segment elevation myocardial infarction (STEMI) patients. BACKGROUND The degree and rapidity of IPA after prasugrel alone with or without concomitant glycoprotein IIb/IIIa inhibition in STEMI patients is unknown. METHODS A total of 100 STEMI patients randomly received prasugrel 60 mg versus 25 μg/kg tirofiban bolus with or without post-bolus 2-h infusion of tirofiban, with or without concomitant prasugrel. IPA at light transmission aggregometry was performed throughout 24 h. The primary endpoint was IPA stimulated with 20 μmol/l adenosine diphosphate (ADP) at 30 min. RESULTS At 30 min, patients in the prasugrel group showed a significantly lower IPA to 20 μmol/l ADP stimulation as compared with tirofiban-treated patients (36 ± 35 vs. 87 ± 31, p < 0.0001). Similarly, patients taking prasugrel showed a suboptimal degree of platelet inhibition for at least 2 h compared with tirofiban patients. Post-bolus tirofiban infusion was necessary to maintain a high level of IPA beyond 1 h after bolus administration if concomitant clopidogrel was given, whereas the bolus-only tirofiban and concomitant prasugrel led to the higher and more consistent IPA levels after both ADP and thrombin receptor-activating peptide stimuli than either therapy alone. CONCLUSIONS Our study shows that prasugrel administration leads to a suboptimal IPA for at least 2 h in STEMI patients. Yet, prasugrel, given in association with a bolus only of glycoprotein IIb/IIIa inhibitor, obviates the need of post-bolus infusion and almost completely abolishes residual variability of IPA after treatment. (Facilitation through Aggrastat By drOpping or shortening Infusion Line in patients with ST-segment elevation myocardial infarction compared to or on top of PRasugrel given at loading dOse [The FABOLUS PRO trial]; NCT01336348).
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Rollini F, Tello-Montoliu A, Angiolillo DJ. Atopaxar: a review of its mechanism of action and role in patients with coronary artery disease. Future Cardiol 2012; 8:503-11. [PMID: 22871190 DOI: 10.2217/fca.12.35] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Platelet activation and aggregation is a complex and key process in thrombus formation after the rupture of an atherosclerotic plaque, which can lead to an acute coronary syndrome. Aspirin, an irreversible inhibitor of thromboxane A2 synthesis, in combination with an inhibitor of P2Y12 ADP platelet receptors (clopidogrel, prasugrel or ticagrelor), represents the current standard of care of antiplatelet therapy for patients with acute coronary syndrome and in those patients undergoing percutaneous coronary intervention. Despite the benefit of these agents, the risk of thrombotic events and bleeding complications may still occur while on such antiplatelet treatment regimens, thus representing an important limitation. Thrombin is one of the most important platelet activators. The inhibition of thrombin-mediated platelet activation by means of protease-activated receptor-1 inhibitors represents an attractive therapeutic option for patients with atherothrombotic disease processes. This article provides an overview on atopaxar (E5555), an orally active protease-activated receptor-1 antagonist that has recently completed Phase II clinical investigation.
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Affiliation(s)
- Fabiana Rollini
- University of Florida College of Medicine-Jacksonville, 655 West 8th Street Jacksonville, FL 32209, USA
| | - Antonio Tello-Montoliu
- University of Florida College of Medicine-Jacksonville, 655 West 8th Street Jacksonville, FL 32209, USA
| | - Dominick J Angiolillo
- University of Florida College of Medicine-Jacksonville, 655 West 8th Street Jacksonville, FL 32209, USA
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Lee H, Hamilton JR. Physiology, pharmacology, and therapeutic potential of protease-activated receptors in vascular disease. Pharmacol Ther 2012; 134:246-59. [DOI: 10.1016/j.pharmthera.2012.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 01/09/2023]
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Tello-Montoliu A, Tomasello SD, Ueno M, Angiolillo DJ. Antiplatelet therapy: thrombin receptor antagonists. Br J Clin Pharmacol 2012; 72:658-71. [PMID: 21906120 DOI: 10.1111/j.1365-2125.2010.03884.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Activated platelets stimulate thrombus formation in response to rupture of an atherosclerotic plaque or endothelial cell erosion, promoting atherothrombotic disease. Multiple pathways contribute to platelet activation. Aspirin, an irreversible inhibitor of thromboxane A2 synthesis, in combination with clopidogrel, an inhibitor of P2Y(12) adenosine diphosphate platelet receptors, represent the current standard-of-care of antiplatelet therapy for patients with acute coronary syndrome and for those undergoing percutaneous coronary intervention. Although these agents have demonstrated significant clinical benefit, the increased risk of bleeding and the recurrence of thrombotic events represent substantial limitations. Thrombin is one of the most important platelet activators. The inhibition of protease-activated receptor 1 showed a good safety profile in preclinical studies. In fact, phase II studies with vorapaxar (SCH530348) and atopaxar (E5555) showed no increase of bleeding events in addition to the current standard-of-care of antiplatelet therapy. Although the results of phase III trials for both drugs are awaited, this family is a promising new addition to the current clinical practice for patients with atherothrombotic disease, not only as an alternative, but also as additional therapy.
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Park HB, Yang JH, Chung KH. Characterization of the cytokine profile of platelet rich plasma (PRP) and PRP-induced cell proliferation and migration: Upregulation of matrix metalloproteinase-1 and -9 in HaCaT cells. THE KOREAN JOURNAL OF HEMATOLOGY 2011; 46:265-73. [PMID: 22259633 PMCID: PMC3259519 DOI: 10.5045/kjh.2011.46.4.265] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 12/08/2011] [Accepted: 12/13/2011] [Indexed: 11/29/2022]
Abstract
Background The underlying rationale of platelet rich plasma (PRP) therapy is that an injection of concentrated PRP at the site of injury may promote tissue repair via cytokine release from platelets. The molecular mechanisms of PRP therapy in the skin wound healing process are not well understood at present, and would benefit from clarification. Methods PRP was stimulated with angonists for 5 min, and cytokine profile analysis was performed. To investigate the wound healing activity of PRP, cell proliferation and migration analyses were performed in skin cells. The effects of PRP were analyzed on the expression and activity of matrix metalloproteinase (MMP)-1, -2, -9, and the activation of transcription factors. Results Thrombin was found to be a strong stimulator of PRP activation to release growth factors and chemokines. PRP induced cell proliferation and migration in HUVECs, HaCaT cells, and HDFs, as well as MMP-1and MMP-9 expression in HaCaT cells, but PRP did not have a significant effect on the expression or activity of MMPs in HDFs. The transcription factors, including signal transducer and activator of transcription-3 (STAT-3) were found to be phosphorylated following PRP treatment in HaCaT cells. Conclusion In this study, we have identified the cytokine profile of activated PRP after agonist stimulation. We have shown that PRP plays an active role in promoting the proliferation and migration of skin cells via the regulation of MMPs, and this may be applicable to the future development of PRP therapeutics to enhance skin wound healing.
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Affiliation(s)
- Hong-Bum Park
- Department of Applied Bioscience, College of Life Science, CHA University, Sungnam, Korea
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17
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Rosado J. Acidic Ca2+ stores in platelets. Cell Calcium 2011; 50:168-74. [DOI: 10.1016/j.ceca.2010.11.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 11/25/2010] [Accepted: 11/27/2010] [Indexed: 02/06/2023]
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18
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A novel platelet glycoprotein Ib-binding protein with human platelet aggregation-inhibiting activity from Trimeresurus jerdonii venom. Toxicon 2011; 57:672-9. [PMID: 21256857 DOI: 10.1016/j.toxicon.2011.01.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 01/07/2011] [Accepted: 01/12/2011] [Indexed: 11/21/2022]
Abstract
Platelet glycoprotein Ib (GPIb) is a primary adhesion receptor and involved in platelet-related disorders. However, it is difficult to study GPIb-specific platelet stimulation using physiological ligands in vivo. GPIb-binding snake C-type lectins (snaclecs) are useful tools for exploring GPIb in vitro because they act on platelets differently. In the present study, a novel GPIb-binding snaclec, named jerdonibitin, was purified, molecular cloned and characterized from Trimeresurus jerdonii venom. On SDS-polyacrylamide gel electrophoresis, it showed a single band with an apparent molecular weight of 25 kDa under non-reducing conditions and two distinct bands with apparent molecular weights of 15 kDa (α-subunit) and 13 kDa (β-subunit) under reducing conditions. The cDNA sequences of each subunit of jerdonibitin were identified and both deduced amino acid sequences were confirmed by N-terminal protein sequencing and trypsin-digested peptide mass fingerprinting of MALDI-TOF. Sequence alignment showed that jerdonibitin is a snaclec and has sequence similarity with TSV-GPIb-BP (a GPIb-inhibitory snaclec). Jerdonibitin dose-dependently inhibited platelet aggregation induced by ristocetin or low-dose thrombin, but not by high-dose thrombin. The GPIbα was detected by affinity chromatography on jerdonibitin. In vivo, jerdonibitin also dose-dependently induced thrombocytopenia of mice and platelet counts remained at very low level after 18 h intravenous injection. In summary, a novel GPIb-inhibitory snaclec was molecular cloned and characterized, which might provide insights into investigation of how GPIb-inhibitory snaclecs work and development of new antiplatelet agents.
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Leonardi S, Tricoci P, Becker RC. Thrombin Receptor Antagonists for the Treatment of Atherothrombosis. Drugs 2010; 70:1771-83. [DOI: 10.2165/11538060-000000000-00000] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Lova P, Canobbio I, Guidetti GF, Balduini C, Torti M. Thrombin induces platelet activation in the absence of functional protease activated receptors 1 and 4 and glycoprotein Ib-IX-V. Cell Signal 2010; 22:1681-7. [PMID: 20600849 DOI: 10.1016/j.cellsig.2010.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 06/11/2010] [Accepted: 06/21/2010] [Indexed: 11/27/2022]
Abstract
Three different surface receptors mediate thrombin-induced activation and aggregation of human blood platelets: the protease activated receptors 1 and 4 (PAR1 and PAR4), and the glycoprotein (GP) Ibalpha of the GPIb-IX-V complex. However, their relative contribution in the stimulation of specific intracellular signaling pathways by thrombin remains largely controversial. In this work, we have shown that activation of PAR1 and PAR4 by thrombin or by selective activating peptides stimulated phospholipase C, tyrosine kinases, as well as the small GTPase Rap1b, promoted actin polymerization and cytoskeleton reorganization. When platelets were desensitized for both PAR1 and PAR4, high doses of thrombin, were unable to activate Rap1b, but produced a still evident stimulation of phospholipase C, as documented by the measurement of intracellular Ca(2+) mobilization and protein kinase C activation. These events were abrogated upon proteolysis of GPIbalpha by the metalloproteinase mocarhagin. In PAR1- and PAR4-desensitized platelets, thrombin also induced tyrosine phosphorylation of some substrates, but, surprisingly, this event was largely independent of GPIbalpha binding, as it persisted upon platelet treatment with mocarhagin. Similarly, thrombin-induced actin polymerization and cytoskeleton reorganization were only minimally altered upon PAR1 and PAR4 inactivation and GPIbalpha proteolysis. Interestingly, none of these events were elicited by enzymatically inactive thrombin. Finally we found that GPIbalpha cleavage reduced, but did not abrogate, platelet aggregation in PAR1- and PAR4-desensitized platelets. These results identify a novel pathway for platelet activation operated by thrombin independently of PAR1, PAR4 and GPIbalpha.
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Affiliation(s)
- Paolo Lova
- Department of Biochemistry, University of Pavia, via Bassi 21, 27100 Pavia, Italy
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Erez O, Gotsch F, Mazaki-Tovi S, Vaisbuch E, Kusanovic JP, Kim CJ, Chaiworapongsa T, Hoppensteadt D, Fareed J, Than NG, Nhan-Chang CL, Yeo L, Pacora P, Mazor M, Hassan SS, Mittal P, Romero R. Evidence of maternal platelet activation, excessive thrombin generation, and high amniotic fluid tissue factor immunoreactivity and functional activity in patients with fetal death. J Matern Fetal Neonatal Med 2010; 22:672-87. [PMID: 19736615 DOI: 10.1080/14767050902853117] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Fetal death can lead to disseminated intravascular coagulation or fetal death syndrome. However, currently it is not clear what are the changes in the coagulation system in patients with a fetal death without the fetal death syndrome. This study was undertaken to determine: (1) whether fetal death in the absence of fetal death syndrome is associated with changes in hemostatic markers in maternal plasma and amniotic fluid; and (2) whether maternal hypertension or placental abruption are associated with further changes in the hemostatic profile of these patients. METHODS A cross-sectional study included the following: (1) determination of changes in markers of coagulation and platelet activation in patients with a normal pregnancy (n = 71) and patients with fetal demise (FD) without disseminated intravascular coagulation (n = 65); (2) determination of the amniotic fluid (AF)-tissue factor concentration and activity, as well as the concentrations of thrombin-antithrombin III (TAT) complexes in patients with a normal pregnancy (n = 25) and those with a FD (n = 36) who underwent amniocentesis. Plasma and AF concentrations of TAT complexes and TF (an index of thrombin generation), as well as maternal plasma concentrations of sCD40L (a marker of platelet activation), tissue factor pathway inhibitor (TFPI) and prothrombin fragments (PF) 1 + 2 (also an indicator of in vivo thrombin generation) were measured by ELISA. TF and TFPI activity were measured using chromogenic assays. RESULTS (1) patients with FD without hypertension had a higher median maternal plasma sCD40L concentration than normal pregnant women (P < 0.001); (2) patients with FD had a higher median maternal plasma TAT III complexes than women with a normal pregnancy (P < 0.001); (3) the median AF-TF concentration and activity were higher in the FD group than in the normal pregnancy group (P < 0.001 for both); (4) patients with preeclampsia and FD had a higher median maternal plasma immunoreactive TF concentration than both normotensive patients with FD and women with normal pregnancies (P < 0.001 and P = 0.001, respectively); (5) the median plasma TF activity was higher in patients with preeclampsia and FD than that of women with normal pregnancies (P = 0.003); (6) among patients with a FD, those with placental abruption had a higher median AF-TAT complexes concentration than those without abruption (P = 0.0004). CONCLUSIONS Our findings indicate that: (1) mothers with a FD have evidence of increased in vivo thrombin generation and platelet activation than women with normal pregnancies; (2) patients with a FD and hypertension had a higher degree of TF activation than those with fetal death but without hypertension; (3) the AF of women with a FD had a higher median TF concentration and activity than that of normal pregnant women. AF can be a potential source for tissue factor and it participates in the development of fetal death syndrome in patients with a retained dead fetus.
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Affiliation(s)
- Offer Erez
- Perinatology Research Branch, NICHD, NIH, DHHS, Bethesda, Maryland, USA.
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Abstract
Clinical manifestations of atherothrombotic disease, such as acute coronary syndromes, cerebrovascular events, and peripheral arterial disease, are major causes of mortality and morbidity worldwide. Platelet activation and aggregation are ultimately responsible for the progression and clinical presentations of atherothrombotic disease. The current standard of care, dual oral antiplatelet therapy with aspirin and the P2Y(12) adenosine diphosphate (ADP) receptor inhibitor clopidogrel, has been shown to improve outcomes in patients with atherothrombotic disease. However, aspirin and P2Y(12) inhibitors target the thromboxane A(2) and the ADP P2Y(12) platelet activation pathways and minimally affect other pathways, while agonists such as thrombin, considered to be the most potent platelet activator, continue to stimulate platelet activation and thrombosis. This may help explain why patients continue to experience recurrent ischaemic events despite receiving such therapy. Furthermore, aspirin and P2Y(12) receptor antagonists are associated with bleeding risk, as the pathways they inhibit are critical for haemostasis. The challenge remains to develop therapies that more effectively inhibit platelet activation without increasing bleeding complications. The inhibition of the protease-activated receptor-1 (PAR-1) for thrombin has been shown to inhibit thrombin-mediated platelet activation without increasing bleeding in pre-clinical models and small-scale clinical trials. PAR-1 inhibition in fact does not interfere with thrombin-dependent fibrin generation and coagulation, which are essential for haemostasis. Thus PAR-1 antagonism coupled with existing dual oral antiplatelet therapy may potentially offer more comprehensive platelet inhibition without the liability of increased bleeding.
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Affiliation(s)
- Dominick J Angiolillo
- Division of Cardiology, Department of Medicine, University of Florida College of Medicine -Jacksonville, Shands Jacksonville, 655 West 8th St, Jacksonville, FL 32209, USA.
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Navarro-Núñez L, Rivera J, Guerrero JA, Martínez C, Vicente V, Lozano ML. Differential effects of quercetin, apigenin and genistein on signalling pathways of protease-activated receptors PAR(1) and PAR(4) in platelets. Br J Pharmacol 2009; 158:1548-56. [PMID: 19814731 DOI: 10.1111/j.1476-5381.2009.00440.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE The modulation by flavonoids of platelet responses induced by thrombin has been little investigated, and the antiplatelet activity, as well as possible inhibitory mechanisms of these compounds on thrombin signalling, has not yet been elucidated. We explored whether flavonoids affect platelet signalling pathways triggered by thrombin and by the selective activation of its protease-activated receptors (PARs) 1 and 4, and analysed the antagonism of these polyphenols at thrombin receptors. EXPERIMENTAL APPROACH We investigated the effect of a range of polyphenolic compounds on platelet aggregation, 5-HT secretion, intracellular calcium mobilization, protein kinase activity and tyrosine phosphorylation, triggered by thrombin and PAR agonist peptides (PAR-APs). The ability of these flavonoids to bind to thrombin receptors was investigated by competitive radioligand binding assays using (125)I-thrombin. KEY RESULTS Quercetin, apigenin and genistein impaired platelet aggregation, as well as 5-HT release and calcium mobilization, induced by thrombin and PAR-APs. Quercetin and apigenin were inhibitors of protein kinases, but genistein exhibited a minimal ability to suppress platelet phosphorylation. Binding assays did not establish any kind of interaction between thrombin receptors and any of the flavonoids tested. CONCLUSIONS AND IMPLICATIONS Quercetin, apigenin and genistein did not inhibit thrombin responses by interacting with thrombin receptors, but by interfering with intracellular signalling. While inhibition by genistein may be a consequence of affecting calcium mobilization, subsequent platelet secretion and aggregation, for quercetin and apigenin, inhibition of kinase activation may also be involved in the impairment of platelet responses.
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Affiliation(s)
- L Navarro-Núñez
- Centro Regional de Hemodonación, University of Murcia, Spain
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Abstract
Thrombin is a potent agonist of platelets. In the current article, the research on the interaction of thrombin with blood platelets is reviewed starting with the first studies demonstrating the direct action of thrombin on platelets and ending with an analysis of the importance of the protease-activated receptors (PARs) and the GpIb complex. The antithrombin activity of platelets is discussed in terms of the binding of thrombin to receptor(s) on the platelet surface. Evaluation of the PAR receptors and the GpIb supports a model where thrombin binds to the GpIb receptor prior to the proteolysis of the PAR receptor(s). Thus, the maximal hemostatic response requires both PAR receptors and the GpIb receptors.
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Affiliation(s)
- Roger L Lundblad
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27516-6695, USA.
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26
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Ghilotti M, Lova P, Balduini C, Torti M. Epinephrine induces intracellular Ca2+mobilization in thrombin-desensitized platelets: a role for GPIb-IX-V. Platelets 2009; 18:135-42. [PMID: 17365862 DOI: 10.1080/09537100600930938] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In this work we have investigated the ability of epinephrine to trigger the release of intracellular Ca2+ in thrombin-desensitized platelets. Addition of thrombin to platelets in the presence of extracellular EGTA caused a rapid and transient release of Ca2+ from intracellular stores and rendered platelets unresponsive to a second addition of the same agonist. Although epinephrine alone had no effect on intracellular Ca2+ mobilization, its addition to thrombin-desensitized platelets was associated to a rapid and evident secondary release of intracellular Ca2+. This effect of epinephrine was not observed when platelets were desensitized with other agonists able to induce phospholipase C activation, including convulxin, U46619, and ADP. Although the platelet receptor for epinephrine is coupled to the Gi family member Gz, no secondary Ca2+ release was seen in thrombin-desensitized platelets upon stimulation of other Gi-coupled receptors, including the P2Y12 receptor and the CXCR4. Addition of hirudin to thrombin-desensitized platelets prevented epinephrine-promoted secondary release of Ca2+, indicating that thrombin, rather than epinephrine itself, is actually responsible for this event as a consequence of thrombin receptors resensitization. Studies with platelets stimulated with specific PAR1- and PAR4- activating peptides proved that neither one of these thrombin receptors were involved in the secondary epinephrine-assisted Ca2+ release. Moreover, we found that thrombin was still able to induce a reduced, but evident release of Ca2+ from internal stores in PAR1- and PAR4-desensitized platelets, which could be followed by a secondary Ca2+ release upon subsequent addition of epinephrine. Importantly, both the primary and the secondary Ca2+ release induced by thrombin and epinephrine in PAR1- and PAR4-desensitized platelets were abrogated upon cleavage of GPIbalpha by the metalloproteinase mocarhagin. These results demonstrate a direct role of thrombin binding to GPIb-IX-V in the mobilization of Ca2+ from intracellular stores, and reveal that epinephrine can restore this process in desensitized platelets, thus prolonging the effect of thrombin stimulation.
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Affiliation(s)
- Marco Ghilotti
- Department of Biochemistry, University of Pavia, Pavia, Italy
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27
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Guidetti GF, Lova P, Bernardi B, Campus F, Baldanzi G, Graziani A, Balduini C, Torti M. The Gi-coupled P2Y12 receptor regulates diacylglycerol-mediated signaling in human platelets. J Biol Chem 2008; 283:28795-805. [PMID: 18755689 DOI: 10.1074/jbc.m801588200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Stimulation of G(q)-coupled receptors activates phospholipase C and is supposed to promote both intracellular Ca(2+) mobilization and protein kinase C (PKC) activation. We found that ADP-induced phosphorylation of pleckstrin, the main platelet substrate for PKC, was completely inhibited not only by an antagonist of the G(q)-coupled P2Y1 receptor but also upon blockade of the G(i)-coupled P2Y12 receptor. The role of G(i) on PKC regulation required stimulation of phosphatidylinositol 3-kinase rather than inhibition of adenylyl cyclase. P2Y12 antagonists also inhibited pleckstrin phosphorylation, Rap1b activation, and platelet aggregation induced upon G(q) stimulation by the thromboxane A(2) analogue U46619. Importantly, activation of phospholipase C and intracellular Ca(2+) mobilization occurred normally. Phorbol 12-myristate 13-acetate overcame the inhibitory effect of P2Y12 receptor blockade on PKC activation but not on Rap1b activation and platelet aggregation. By contrast, inhibition of diacylglycerol kinase restored both PKC and Rap1b activity and caused platelet aggregation. Stimulation of P2Y12 receptor or direct inhibition of diacylglycerol kinase potentiated the effect of membrane-permeable sn-1,2-dioctanoylglycerol on platelet aggregation and pleckstrin phosphorylation, in association with inhibition of its phosphorylation to phosphatidic acid. These results reveal a novel and unexpected role of the G(i)-coupled P2Y12 receptor in the regulation of diacylglycerol-mediated events in activated platelets.
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Affiliation(s)
- Gianni F Guidetti
- Center of Excellence for Applied Biology, Department of Biochemistry, University of Pavia, via Bassi 21, 27100 Pavia, Italy
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Intracellular Calcium Release from Human Platelets: Different Messengers for Multiple Stores. Trends Cardiovasc Med 2008; 18:57-61. [DOI: 10.1016/j.tcm.2007.12.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 11/22/2007] [Accepted: 12/06/2007] [Indexed: 11/24/2022]
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Jardin I, Ben Amor N, Hernández-Cruz JM, Salido GM, Rosado JA. Involvement of SNARE proteins in thrombin-induced platelet aggregation: Evidence for the relevance of Ca2+ entry. Arch Biochem Biophys 2007; 465:16-25. [PMID: 17543880 DOI: 10.1016/j.abb.2007.04.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 04/27/2007] [Accepted: 04/29/2007] [Indexed: 10/23/2022]
Abstract
Thrombin induces platelet activation through a variety of intracellular mechanisms, including Ca(2+) mobilization. The protein of the exocytotic machinery SNAP-25, but not VAMPs, is required for store-operated Ca(2+) entry, the main mechanism for Ca(2+) influx in platelets. Hence, we have investigated the role of the SNAP-25 and VAMPs in thrombin-induced platelet aggregation. Platelet stimulation with thrombin or selective activation of thrombin receptors PAR-1, PAR-4 or GPIb-IX-V results in platelet aggregation that, except for GPIb-IX-V receptor, requires Ca(2+) entry for full activation. Depletion of the intracellular Ca(2+) stores using pharmacological tools was unable to induce aggregation except when cytosolic Ca(2+) concentration reached a critical level (around 1.5 microM). Electrotransjection of cells with anti-SNAP-25 antibody reduced thrombin-evoked platelet aggregation, while electrotransjection of anti-VAMP-1, -2 and -3 antibody had no effect. These findings support a role for SNAP-25 but not VAMP-1, -2 and -3 in platelet aggregation, which is likely mediated by the regulation of Ca(2+) mobilization in human platelets.
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Affiliation(s)
- Isaac Jardin
- Department of Physiology, Cellular Physiology Research Group, University of Extremadura, Av. Universidad s/n, Cáceres 10071, Spain
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30
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Redondo PC, Harper AGS, Sage SO, Rosado JA. Dual role of tubulin-cytoskeleton in store-operated calcium entry in human platelets. Cell Signal 2007; 19:2147-54. [PMID: 17681754 DOI: 10.1016/j.cellsig.2007.06.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Accepted: 06/15/2007] [Indexed: 11/30/2022]
Abstract
Two mechanisms for store-operated Ca(2+) entry (SOCE) regulated by two independent Ca(2+) stores, the dense tubular system (DTS) and the acidic stores, have been described in platelets. We have previously suggested that coupling between the type II IP(3) receptor (IP(3)RII) and hTRPC1, involving reorganization of the actin microfilaments, play an important role in SOCE. However, the involvement of the tubulin microtubules, located beneath the plasma membrane, remains unclear. Here we show that the microtubule disrupting agent colchicine reduced Ca(2+) entry stimulated by low concentrations (0.1 U/mL) of thrombin, which activates SOCE mostly by depleting acidic Ca(2+)-store. Consistently, colchicine reduced SOCE activated by 2,5 di-(tertbutyl)-1,4-hydroquinone (TBHQ), which selectively depletes the acidic Ca(2+) stores. In contrast, colchicine enhanced SOCE mediated by depletion of the DTS, induced by high concentrations of thapsigargin (TG), which depletes both the acidic Ca(2+) stores and the DTS, the major releasable Ca(2+) store in platelets. These findings were confirmed by using Sr(2+) as a surrogate for Ca(2+) entry. Colchicine attenuated the coupling between IP(3)RII and hTRPC1 stimulated by thrombin while it enhanced that evoked by TG. Paclitaxel, which induces microtubular stabilization and polymerization, exerted the opposite effects on thrombin- and TG-evoked SOCE and coupling between IP(3)RII and hTRPC1 compared with colchicine. Neither colchicine nor paclitaxel altered the ability of platelets to extrude Ca(2+). These findings suggest that tubulin microtubules play a dual role in SOCE, acting as a barrier that prevents constitutive SOCE regulated by DTS, but also supporting SOCE mediated by the acidic Ca(2+) stores.
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Affiliation(s)
- Pedro C Redondo
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, Downing Site, UK.
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31
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Jardin I, Ben Amor N, Bartegi A, Pariente J, Salido G, Rosado J. Differential involvement of thrombin receptors in Ca2+ release from two different intracellular stores in human platelets. Biochem J 2007; 401:167-74. [PMID: 16939417 PMCID: PMC1698687 DOI: 10.1042/bj20060888] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Physiological agonists increase cytosolic free Ca2+ concentration to regulate a number of cellular processes. The platelet thrombin receptors, PAR (protease-activated receptor) 1 PAR-4 and GPIb-IX-V (glycoprotein Ib-IX-V) have been described as potential contributors of thrombin-induced platelet aggregation. Platelets present two separate Ca2+ stores, the DTS (dense tubular system) and acidic organelles, differentiated by the distinct sensitivity of their respective SERCAs (sarcoplasmic/endoplasmic-reticulum Ca2+-ATPases) to TG (thapsigargin) and TBHQ [2,5-di-(tert-butyl)-1,4-hydroquinone]. However, the involvement of the thrombin receptors in Ca2+ release from each Ca2+ store remains unknown. Depletion of the DTS using ADP, which releases Ca2+ solely from the DTS, in combination with 10 nM TG, to selectively inhibit SERCA2 located on the DTS reduced Ca2+ release evoked by the PAR-1 agonist, SFLLRN, and the PAR-4 agonist, AYPGKF, by 80 and 50% respectively. Desensitization of PAR-1 and PAR-4 or pre-treatment with the PAR-1 and PAR-4 antagonists SCH 79797 and tcY-NH2 reduced Ca2+ mobilization induced by thrombin, and depletion of the DTS after desensitization or blockade of PAR-1 and PAR-4 had no significant effect on Ca2+ release stimulated by thrombin through the GPIb-IX-V receptor. Converse experiments showed that depletion of the acidic stores using TBHQ reduced Ca2+ release evoked by SFLLRN or AYPGKF, by 20 and 50% respectively, and abolished thrombin-stimulated Ca2+ release through the GPIb-IX-V receptor when PAR-1 and PAR-4 had been desensitized or blocked. Our results indicate that thrombin-induced activation of PAR-1 and PAR-4 evokes Ca2+ release from both Ca2+ stores, while activation of GPIb-IX-V by thrombin releases Ca2+ solely from the acidic compartments in human platelets.
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Affiliation(s)
- Isaac Jardin
- *Cell Physiology Research Group, Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
| | - Nidhal Ben Amor
- †Unité de Recherche de Biochimie, Inst. Superieur de Biotechnologie, Monastir, Tunisia
| | - Ahgleb Bartegi
- †Unité de Recherche de Biochimie, Inst. Superieur de Biotechnologie, Monastir, Tunisia
| | - José A. Pariente
- *Cell Physiology Research Group, Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
| | - Ginés M. Salido
- *Cell Physiology Research Group, Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
| | - Juan A. Rosado
- *Cell Physiology Research Group, Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
- To whom correspondence should be addressed (email )
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Bolton-Maggs PHB, Chalmers EA, Collins PW, Harrison P, Kitchen S, Liesner RJ, Minford A, Mumford AD, Parapia LA, Perry DJ, Watson SP, Wilde JT, Williams MD. A review of inherited platelet disorders with guidelines for their management on behalf of the UKHCDO. Br J Haematol 2006; 135:603-33. [PMID: 17107346 DOI: 10.1111/j.1365-2141.2006.06343.x] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The inherited platelet disorders are an uncommon cause of symptomatic bleeding. They may be difficult to diagnose (and are likely to be under-diagnosed) and pose problems in management. This review discusses the inherited platelet disorders summarising the current state of the art with respect to investigation and diagnosis and suggests how to manage bleeding manifestations with particular attention to surgical interventions and the management of pregnancy.
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Greco F, Ciana A, Pietra D, Balduini C, Minetti G, Torti M. Rap2, but not Rap1 GTPase is expressed in human red blood cells and is involved in vesiculation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:330-5. [PMID: 16540189 DOI: 10.1016/j.bbamcr.2006.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 01/30/2006] [Accepted: 02/06/2006] [Indexed: 11/30/2022]
Abstract
Recent studies have suggested that Rap1 and Rap2 small GTP-binding proteins are both expressed in human red blood cells (RBCs). In this work, we carefully examined the expression of Rap proteins in leukocytes- and platelets-depleted RBCs, whose purity was established on the basis of the selective expression of the beta2 subunit of the Na+/K+ -ATPase, as verified according to the recently proposed "beta-profiling test" [J.F. Hoffman, A. Wickrema, O. Potapova, M. Milanick, D.R. Yingst, Na pump isoforms in human erythroid progenitor cells and mature erythrocytes, Proc. Natl. Acad. Sci. U. S. A. 99 (2002) 14572-14577]. In pure RBCs preparations, Rap2, but not Rap1 was detected immunologically. RT-PCR analysis of mRNA extracted from highly purified reticulocytes confirmed the expression of Rap2b, but not Rap2a, Rap2c, Rap1a or Rap1b. In RBCs, Rap2 was membrane-associated and was rapidly activated upon treatment with Ca2+/Ca2+ -ionophore. In addition, Rap2 segregated and was selectively enriched into microvesicles released by Ca2+ -activated RBCs, suggesting a possible role for this GTPase in membrane shedding.
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Affiliation(s)
- Fabio Greco
- Department of Biochemistry, University of Pavia, Via Bassi 21, 27100 Pavia, Italy
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Keuren JFW, Wielders SJH, Ulrichts H, Hackeng T, Heemskerk JWM, Deckmyn H, Bevers EM, Lindhout T. Synergistic Effect of Thrombin on Collagen-Induced Platelet Procoagulant Activity Is Mediated Through Protease-Activated Receptor-1. Arterioscler Thromb Vasc Biol 2005; 25:1499-505. [PMID: 15845904 DOI: 10.1161/01.atv.0000167526.31611.f6] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE In the blood coagulation process, the rate of thrombin formation is critically dependent on phosphatidylserine (PtdSer) at the surface of activated platelets. Thrombin synergistically enhances the collagen-induced platelet procoagulant response. The objective of this study is to elucidate the mechanism of this synergistic action with a focus on the intracellular Ca2+ concentration ([Ca2+]i) and the various platelet receptors for thrombin. METHODS AND RESULTS We demonstrate that procoagulant activity is related to a sustained increased [Ca2+]i, which in turn depends on extracellular Ca2+ influx. Increased PtdSer exposure coincides with increased [Ca2+]i and was observed in a subpopulation (approximately 14%) of the platelets after stimulation with thrombin plus collagen. 2D2-Fab fragments against the thrombin binding site on GPIbalpha made clear that this receptor did not signal for platelet procoagulant activity. Inhibition of protease-activated receptor 1 (PAR-1) and PAR-4 by selective intracellular inhibitors and selective desensitization of these receptors revealed that PAR-1, but not PAR-4, activation is a prerequisite for both sustained elevations in [Ca2+]i and procoagulant activity induced by collagen plus thrombin. CONCLUSIONS The interaction of thrombin with PAR-1 mediates a synergistic effect on collagen-induced procoagulant activity by inducing a sustained elevation in [Ca2+]i in a subpopulation of platelets.
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Canobbio I, Noris P, Pecci A, Balduini A, Balduini CL, Torti M. Altered cytoskeleton organization in platelets from patients with MYH9-related disease. J Thromb Haemost 2005; 3:1026-35. [PMID: 15869600 DOI: 10.1111/j.1538-7836.2005.01244.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
MYH9-related disease (MYH9-RD) is an autosomal dominant disorder deriving from mutations in the MYH9 gene encoding for the heavy chain of non-muscle myosin IIA, and characterized by thrombocytopenia and giant platelets. Isoform IIA of myosin is the only one expressed in platelets, but the possibility that MYH9 mutations affect the organization of contractile structures in these blood elements has never been investigated. In this work we have analyzed the composition and the agonist-induced reorganization of the platelet cytoskeleton from seven MYH9-RD patients belonging to four different families. We found that an increased amount of myosin was constitutively associated with actin in the cytoskeleton of resting MYH9-RD platelets. Upon platelet stimulation, an impaired increase in the total cytoskeletal proteins was observed. Moreover, selected membrane glycoproteins, tyrosine kinases, and small GTPases failed to interact with the cytoskeleton in agonist-stimulated MYH9-RD platelets. These results demonstrate for the first time that mutations of MYH9 result in an alteration of the composition and agonist-induced reorganization of the platelet cytoskeleton. We suggest that these abnormalities may represent the biochemical basis for the previously reported functional alterations of MYH9-RD platelets, and for the abnormal platelet formation from megakaryocytes, resulting in thrombocytopenia and giant platelets.
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Affiliation(s)
- I Canobbio
- Centre of Excellence for Applied Biology, Department of Biochemistry, University of Pavia, Pavia, Italy
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Campus F, Lova P, Bertoni A, Sinigaglia F, Balduini C, Torti M. Thrombopoietin complements G(i)- but not G(q)-dependent pathways for integrin {alpha}(IIb){beta}(3) activation and platelet aggregation. J Biol Chem 2005; 280:24386-95. [PMID: 15863506 DOI: 10.1074/jbc.m501174200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Binding of thrombopoietin (TPO) to the cMpl receptor on human platelets potentiates aggregation induced by a number of agonists, including ADP. In this work, we found that TPO was able to restore ADP-induced platelet aggregation upon blockade of the G(q)-coupled P2Y1 purinergic receptor but not upon inhibition of the G(i)-coupled P2Y12 receptor. Moreover, TPO triggered platelet aggregation upon co-stimulation of G(z) by epinephrine but not upon co-stimulation of G(q) by the thromboxane analogue U46619. Platelet aggregation induced by TPO and G(i) stimulation was biphasic, and cyclooxygenase inhibitors prevented the second but not the first phase. In contrast to ADP, TPO was unable to induce integrin alpha(IIb)beta(3) activation, as evaluated by binding of both fibrinogen and PAC-1 monoclonal antibody. However, ADP-induced activation of integrin alpha(IIb)beta(3) was blocked by antagonists of the G(q)-coupled P2Y1 receptor but was completely restored by the simultaneous co-stimulation of cMpl receptor by TPO. Inside-out activation of integrin alpha(IIb)beta(3) induced by TPO and G(i) stimulation occurred independently of thromboxane A(2) production and was not mediated by protein kinase C, MAP kinases, or Rho-dependent kinase. Importantly, TPO and G(i) activation of integrin alpha(IIb)beta(3) was suppressed by wortmannin and Ly294002, suggesting a critical regulation by phosphatidylinositol 3-kinase. We found that TPO did not activate phospholipase C in human platelets and was unable to restore ADP-induced phospholipase C activation upon blockade of the G(q)-coupled P2Y1 receptor. TPO induced a rapid and sustained activation of the small GTPase Rap1B through a pathway dependent on phosphatidylinositol 3-kinase. In ADP-stimulated platelets, Rap1B activation was reduced, although not abolished, upon blockade of the P2Y1 receptor. However, accumulation of GTP-bound Rap1B in platelets activated by co-stimulation of cMpl and P2Y12 receptor was identical to that induced by the simultaneous ligation of P2Y1 and P2Y12 receptor by ADP. These results indicate that TPO can integrate G(i), but not G(q), stimulation and can efficiently support integrin alpha(IIb)beta(3) activation platelet aggregation by an alternative signaling pathway independent of phospholipase C but involving the phosphatidylinositol 3-kinase and the small GTPase Rap1B.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Adenosine Diphosphate/chemistry
- Androstadienes/pharmacology
- Antibodies, Monoclonal/chemistry
- Blood Platelets/cytology
- Blood Proteins/chemistry
- Blood Proteins/metabolism
- Calcium/metabolism
- Chromones/pharmacology
- Cyclooxygenase Inhibitors/pharmacology
- Cytosol/metabolism
- Enzyme Activation
- Enzyme Inhibitors/pharmacology
- Fibrinogen/chemistry
- Fibrinogen/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/physiology
- GTP-Binding Protein alpha Subunits, Gq-G11/genetics
- GTP-Binding Protein alpha Subunits, Gq-G11/physiology
- Humans
- Morpholines/pharmacology
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphoproteins/chemistry
- Phosphoproteins/metabolism
- Platelet Activation
- Platelet Aggregation
- Platelet Glycoprotein GPIIb-IIIa Complex/metabolism
- Protein Binding
- Proto-Oncogene Proteins/metabolism
- Receptors, Cytokine/metabolism
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2Y1
- Receptors, Thrombopoietin
- Thrombopoietin/chemistry
- Thrombopoietin/genetics
- Thrombopoietin/metabolism
- Thrombopoietin/physiology
- Thromboxane A2/metabolism
- Thromboxanes/chemistry
- Time Factors
- Type C Phospholipases/metabolism
- Wortmannin
- rap GTP-Binding Proteins/metabolism
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Affiliation(s)
- Francesca Campus
- Department of Biochemistry, University of Pavia, via Bassi 21, 27100 Pavia
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