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Souza RP, Pimentel VD, de Sousa RWR, Sena EP, da Silva ACA, Dittz D, Ferreira PMP, de Oliveira AP. Non-clinical investigations about cytotoxic and anti-platelet activities of gamma-terpinene. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024:10.1007/s00210-024-03173-w. [PMID: 38801455 DOI: 10.1007/s00210-024-03173-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Accepted: 05/18/2024] [Indexed: 05/29/2024]
Abstract
Gamma-terpinene (γ-TPN) is a cyclohexane monoterpene isolated from plant essential oils, such as tea tree (Melaleuca alternifolia), oregano (Origanum vulgare), rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris Marchand), and eucalyptus (Eucalyptus sp.). Terpenes are widely studied molecules pharmacologically active on the cardiovascular system, hemostasis, and antioxidant actions. Herein, it was investigated the cytotoxic and antiplatelet activity of γ-TPN using different non-clinical laboratory models. For in silico evaluation, the PreADMET, SwissADME, and SwissTargetPrediction softwares were used. Molecular docking was performed using the AutoDockVina and BIOVIA Discovery Studio databases. The cytotoxicity of γ-TPN was analyzed by the MTT assay upon normal murine endothelial SVEC4-10 and fibroblast L-929 cells. Platelet aggregation was evaluated with platelet-rich (PRP) and platelet-poor (PPP) plasma from spontaneously hypertensive rats (SHR), in addition to SVEC4-10 cells pre-incubated with γ-TPN (50, 100, and 200 µM) for 24 h. SHR animals were pre-treated by gavage with γ-TPN for 7 days and divided into four groups (negative control, 25, 50, and 100 mg/kg). Blood samples were collected to measure nitrite using the Griess reagent. Gamma-TPN proved to be quite lipid-soluble (Log P = +4.50), with a qualified profile of similarity to the drug, good bioavailability, and adequate pharmacokinetics. It exhibited affinity mainly for the P2Y12 receptor (6.450 ± 0.232 Kcal/mol), moderate cytotoxicity for L-929 (CC50 = 333.3 µM) and SVEC 4-10 (CC50 = 366.7 µM) cells. The presence of γ-TPN in SVEC 4-10 cells was also able to reduce platelet aggregation by 51.57 and 44.20% at lower concentrations (50 and 100 µM, respectively). Then, γ-TPN has good affinity with purinergic receptors and an effect on the reversal of platelet aggregation and oxidative stress, being promising and safe for therapeutic targets and subsequent studies on the control of thromboembolic diseases.
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Affiliation(s)
- Railson Pereira Souza
- Postgraduate Program in Pharmacology, Center for Research on Medicinal Plants (NPPM), Federal University of Piauí, Teresina, 64049-550, Brazil
- Laboratory of Cardiovascular Pharmacology (Lafac), Federal University of Piauí, Teresina, 64049-550, Brazil
| | - Vinícius Duarte Pimentel
- Postgraduate Program in Pharmacology, Center for Research on Medicinal Plants (NPPM), Federal University of Piauí, Teresina, 64049-550, Brazil
| | - Rayran Walter Ramos de Sousa
- Department of Biophysics and Physiology, Federal University of Piauí, Teresina, 64049-550, Brazil
- Laboratory of Experimental Cancerology (LabCancer), Federal University of Piauí, Teresina, 64049-550, Brazil
| | - Emerson Portela Sena
- Postgraduate Program in Pharmacology, Center for Research on Medicinal Plants (NPPM), Federal University of Piauí, Teresina, 64049-550, Brazil
- Laboratory of Cardiovascular Pharmacology (Lafac), Federal University of Piauí, Teresina, 64049-550, Brazil
| | - Alda Cássia Alves da Silva
- Postgraduate Program in Pharmacology, Center for Research on Medicinal Plants (NPPM), Federal University of Piauí, Teresina, 64049-550, Brazil
| | - Dalton Dittz
- Postgraduate Program in Pharmacology, Center for Research on Medicinal Plants (NPPM), Federal University of Piauí, Teresina, 64049-550, Brazil
- Laboratory of Antineoplastic Pharmacology (Lafan), Department of Biochemistry and Pharmacology, Federal University of Piauí, Teresina, 64049-550, Brazil
| | - Paulo Michel Pinheiro Ferreira
- Department of Biophysics and Physiology, Federal University of Piauí, Teresina, 64049-550, Brazil
- Laboratory of Experimental Cancerology (LabCancer), Federal University of Piauí, Teresina, 64049-550, Brazil
| | - Aldeídia Pereira de Oliveira
- Postgraduate Program in Pharmacology, Center for Research on Medicinal Plants (NPPM), Federal University of Piauí, Teresina, 64049-550, Brazil.
- Laboratory of Cardiovascular Pharmacology (Lafac), Federal University of Piauí, Teresina, 64049-550, Brazil.
- Department of Biophysics and Physiology, Federal University of Piauí, Teresina, 64049-550, Brazil.
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Fernández DI, Troitiño S, Sobota V, Tullemans BME, Zou J, van den Hurk H, García Á, Honarnejad S, Kuijpers MJE, Heemskerk JWM. Ultra-high throughput-based screening for the discovery of antiplatelet drugs affecting receptor dependent calcium signaling dynamics. Sci Rep 2024; 14:6229. [PMID: 38486006 PMCID: PMC10940705 DOI: 10.1038/s41598-024-56799-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/11/2024] [Indexed: 03/18/2024] Open
Abstract
Distinct platelet activation patterns are elicited by the tyrosine kinase-linked collagen receptor glycoprotein VI (GPVI) and the G-protein coupled protease-activated receptors (PAR1/4) for thrombin. This is reflected in the different platelet Ca2+ responses induced by the GPVI agonist collagen-related peptide (CRP) and the PAR1/4 agonist thrombin. Using a 96 well-plate assay with human Calcium-6-loaded platelets and a panel of 22 pharmacological inhibitors, we assessed the cytosolic Ca2+ signaling domains of these receptors and developed an automated Ca2+ curve algorithm. The algorithm was used to evaluate an ultra-high throughput (UHT) based screening of 16,635 chemically diverse small molecules with orally active physicochemical properties for effects on platelets stimulated with CRP or thrombin. Stringent agonist-specific selection criteria resulted in the identification of 151 drug-like molecules, of which three hit compounds were further characterized. The dibenzyl formamide derivative ANO61 selectively modulated thrombin-induced Ca2+ responses, whereas the aromatic sulfonyl imidazole AF299 and the phenothiazine ethopropazine affected CRP-induced responses. Platelet functional assays confirmed selectivity of these hits. Ethopropazine retained its inhibitory potential in the presence of plasma, and suppressed collagen-dependent thrombus buildup at arterial shear rate. In conclusion, targeting of platelet Ca2+ signaling dynamics in a screening campaign has the potential of identifying novel platelet-inhibiting molecules.
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Affiliation(s)
- Delia I Fernández
- The Department of Biochemistry, CARIM, Maastricht University, 6229 ER, Maastricht, The Netherlands
- Platelet Proteomics Group, CiMUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - Sara Troitiño
- Platelet Proteomics Group, CiMUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - Vladimír Sobota
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, 33604, Bordeaux, France
- Institut de Mathématiques de Bordeaux, UMR5251, University of Bordeaux, 33 405, Talence, France
| | - Bibian M E Tullemans
- The Department of Biochemistry, CARIM, Maastricht University, 6229 ER, Maastricht, The Netherlands
- Synapse Research Institute, Kon. Emmaplein 7, 6217 KD, Maastricht, The Netherlands
| | - Jinmi Zou
- The Department of Biochemistry, CARIM, Maastricht University, 6229 ER, Maastricht, The Netherlands
- Synapse Research Institute, Kon. Emmaplein 7, 6217 KD, Maastricht, The Netherlands
| | | | - Ángel García
- Platelet Proteomics Group, CiMUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | | | - Marijke J E Kuijpers
- The Department of Biochemistry, CARIM, Maastricht University, 6229 ER, Maastricht, The Netherlands.
- Thrombosis Expertise Centre, Heart and Vascular Centre, Maastricht University Medical Centre+, 6229 HX, Maastricht, The Netherlands.
| | - Johan W M Heemskerk
- The Department of Biochemistry, CARIM, Maastricht University, 6229 ER, Maastricht, The Netherlands.
- Synapse Research Institute, Kon. Emmaplein 7, 6217 KD, Maastricht, The Netherlands.
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Francis LRA, Millington-Burgess SL, Rahman T, Harper MT. Q94 is not a selective modulator of proteinase-activated receptor 1 (PAR1) in platelets. Platelets 2022; 33:1090-1095. [PMID: 35417662 DOI: 10.1080/09537104.2022.2026911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Thrombin is a potent platelet activator, acting through proteinase-activated receptors -1 and -4 (PAR1 and PAR4). Of these, PAR-1 is activated more rapidly and by lower thrombin concentrations. Consequently, PAR-1 has been extensively investigated as a target for anti-platelet drugs to prevent myocardial infarction. Q94 has been reported to act as an allosteric modulator of PAR1, potently and selectively inhibiting PAR1-Gαq coupling in multiple cell lines, but its effects on human platelet activation have not been previously studied. Platelet Ca2+ signaling, integrin αIIbβ3 activation and α-granule secretion were monitored following stimulation by a PAR1-activating peptide (PAR1-AP). Although Q94 inhibited these responses, its potency was low compared to other PAR1 antagonists. In addition, αIIbβ3 activation and α-granule secretion in response to other platelet activators were also inhibited with similar potency. Finally, in endothelial cells, Q94 did not inhibit PAR1-dependent Ca2+ signaling. Our data suggest that Q94 may have PAR1-independent off-target effects in platelets, precluding its use as a selective PAR1 allosteric modulator.
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Affiliation(s)
- Luc R A Francis
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | | | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Matthew T Harper
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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4
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Berry J, Harper MT. Protease-activated receptor antagonists prevent thrombosis when dual antiplatelet therapy is insufficient in an occlusive thrombosis microfluidic model. Res Pract Thromb Haemost 2022; 6:e12703. [PMID: 35434469 PMCID: PMC9001860 DOI: 10.1002/rth2.12703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/11/2022] [Accepted: 03/08/2022] [Indexed: 11/23/2022] Open
Abstract
Background Platelet activation and arterial thrombosis on a ruptured atherosclerotic plaque is a major cause of myocardial infarction. Dual antiplatelet therapy (DAPT), the combination of platelet aggregation inhibitors, aspirin and a P2Y12 antagonist, is used to prevent arterial thrombosis. However, many people continue to have arterial thrombosis and myocardial infarction despite DAPT, indicating that additional therapies are required where DAPT is insufficient. Objectives To determine whether antagonists of protease-activated receptors (PARs) can prevent occlusive thrombosis under conditions where DAPT is insufficient. Methods We used human whole blood in a microfluidic model of occlusive thrombosis to compare conditions under which DAPT is effective to those under which DAPT was not. Cangrelor (a P2Y12 antagonist) and aspirin were used to mimic DAPT. We then investigated whether the PAR1 antagonist vorapaxar or the PAR4 antagonist BMS 986120, alone or in combination with DAPT, prevented occlusive thrombosis. Results and Conclusions A ruptured plaque exposes collagen fibers and is often rich in tissue factor, triggering activation of platelets and coagulation. Occlusive thrombi formed on type I collagen in the presence or absence of tissue factor (TF). However, although DAPT prevented occlusive thrombosis in the absence of TF, DAPT had little effect when TF was also present. Under these conditions, PAR antagonism was also ineffective. However, occlusive thrombosis was prevented by combining DAPT with PAR antagonism. These data demonstrate that PAR antagonists may be a useful addition to DAPT in some patients and further demonstrate the utility of in vitro models of occlusive thrombosis.
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Affiliation(s)
- Jess Berry
- Department of PharmacologyUniversity of CambridgeCambridgeUK
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5
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Disorders on cardiovascular parameters in rats and in human blood cells caused by Lachesis acrochorda snake venom. Toxicon 2020; 184:180-191. [DOI: 10.1016/j.toxicon.2020.06.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 11/19/2022]
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Ivanov II, Apta BHR, Bonna AM, Harper MT. Platelet P-selectin triggers rapid surface exposure of tissue factor in monocytes. Sci Rep 2019; 9:13397. [PMID: 31527604 PMCID: PMC6746844 DOI: 10.1038/s41598-019-49635-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 08/23/2019] [Indexed: 12/13/2022] Open
Abstract
Tissue factor (TF) plays a central role in haemostasis and thrombosis. Following vascular damage, vessel wall TF initiates the extrinsic coagulation cascade. TF can also be exposed by monocytes. Inflammatory or infectious stimuli trigger synthesis of new TF protein by monocytes over the course of hours. It has also been suggested that monocytes can expose TF within minutes when stimulated by activated platelets. Here, we have confirmed that monocytes rapidly expose TF in whole blood and further demonstrate that platelet P-selectin exposure is necessary and sufficient. Monocyte TF exposure increased within five minutes in response to platelet activation by PAR1-AP, PAR4-AP or CRP-XL. PAR1-AP did not trigger TF exposure on isolated monocytes unless platelets were also present. In whole blood, PAR1-AP-triggered TF exposure required P-selectin and PGSL-1. In isolated monocytes, although soluble recombinant P-selectin had no effect, P-selectin coupled to 2 µm beads triggered TF exposure. Cycloheximide did not affect rapid TF exposure, indicating that de novo protein synthesis was not required. These data show that P-selectin on activated platelets rapidly triggers TF exposure on monocytes. This may represent a mechanism by which platelets and monocytes rapidly contribute to intravascular coagulation.
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Affiliation(s)
- Ivelin I Ivanov
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Bonita H R Apta
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Arkadiusz M Bonna
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Matthew T Harper
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom.
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7
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Sowton AP, Millington-Burgess SL, Murray AJ, Harper MT. Rapid kinetics of changes in oxygen consumption rate in thrombin-stimulated platelets measured by high-resolution respirometry. Biochem Biophys Res Commun 2018; 503:2721-2727. [PMID: 30093113 PMCID: PMC6142173 DOI: 10.1016/j.bbrc.2018.08.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 12/31/2022]
Abstract
Platelet activation plays a key role in normal haemostasis and pathological thrombosis. Platelet activation is rapid; within minutes of stimulation, platelets generate bioactive phospholipids, secrete their granule contents, activate integrins and aggregate together to form a haemostatic plug. These events are dependent on ATP synthesis. Mitochondrial function in platelets from healthy volunteers and patients with a range of diseases indicate an important role for oxygen consumption in oxidative phosphorylation in normal and pathological function. Platelets also consume oxygen during oxidation reactions, such as cyclooxygenase-dependent thromboxane A2 synthesis. In this study, we used high-resolution respirometry to investigate rapid changes in oxygen consumption during platelet activation. We demonstrated a rapid, transient increase in oxygen consumption rate within minutes of platelet stimulation by the physiological activator, thrombin. This was partly inhibited by aspirin and by oligomycin. This shows that high resolution respirometry can provide information regarding rapid and dynamic changes in oxygen consumption during platelet activation. High resolution respirometry can be used to investigate the rapid kinetics of changes in platelet oxygen consumption rate. Thrombin triggers a rapid, transient increase in platelet oxygen consumption rate. Aspirin and oligomycin partially inhibit the increased oxygen consumption rate.
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Affiliation(s)
- Alice P Sowton
- Department of Pharmacology, University of Cambridge, UK; Department of Physiology, Development and Neuroscience, University of Cambridge, UK
| | | | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, UK
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8
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Rwibasira Rudinga G, Khan GJ, Kong Y. Protease-Activated Receptor 4 (PAR4): A Promising Target for Antiplatelet Therapy. Int J Mol Sci 2018; 19:E573. [PMID: 29443899 PMCID: PMC5855795 DOI: 10.3390/ijms19020573] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/09/2018] [Accepted: 02/09/2018] [Indexed: 12/29/2022] Open
Abstract
Cardiovascular diseases (CVDs) are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs), including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR). Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.
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Affiliation(s)
- Gamariel Rwibasira Rudinga
- School of Life Science & Technology, China Pharmaceutical University, 24 Tong Jia Street, Nanjing 210009, China.
| | - Ghulam Jilany Khan
- Jiangsu Center for Pharmacodynamics Research, Evaluation and Drug Screening, China Pharmaceutical University, Nanjing 210009, China.
| | - Yi Kong
- School of Life Science & Technology, China Pharmaceutical University, 24 Tong Jia Street, Nanjing 210009, China.
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Lee H, Sturgeon S, Jackson S, Hamilton J. The contribution of thrombin-induced platelet activation to thrombus growth is diminished under pathological blood shear conditions. Thromb Haemost 2017; 107:328-37. [DOI: 10.1160/th11-06-0418] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 11/04/2011] [Indexed: 11/05/2022]
Abstract
SummaryDeveloping novel anti-platelet therapies is an important clinical strategy for the prevention of arterial thromboses which cause heart attacks and most strokes. Thrombin activates platelets via protease-activated receptors (PARs), and PAR antagonists are currently under investigation as antithrombotics. Yet despite these clinical advances, the importance of PARs to platelet activation during thromboses formed under pathological conditions has not been investigated. To this end, we examined the role of PAR-dependent platelet activation in thrombus formation in the presence of elevated blood shear rates. We used two in vivo thrombosis models and an ex vivo whole blood flow approach in PAR4-/-mice, whose platelets are unresponsive to thrombin, to show that the contribution of PAR-mediated platelet activation to thrombosis is diminished at pathological blood shear rates as a direct result of decreased incorporation of thrombin-activated platelets into growing thrombi. Our ex vivo observations were replicated in human whole blood treated with a PAR1 antagonist. These results define a novel, shear-regulated role for thrombin/PAR-dependent platelet activation during thrombosis and provide important insights into the conditions under which PAR antagonists may best be used for the prevention of acute coronary syndromes.
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10
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French SL, Arthur JF, Lee H, Nesbitt WS, Andrews RK, Gardiner EE, Hamilton JR. Inhibition of protease-activated receptor 4 impairs platelet procoagulant activity during thrombus formation in human blood. J Thromb Haemost 2016; 14:1642-54. [PMID: 26878340 DOI: 10.1111/jth.13293] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 01/26/2016] [Indexed: 01/11/2023]
Abstract
UNLABELLED Essentials The platelet thrombin receptor, PAR4, is an emerging anti-thrombotic drug target. We examined the anti-platelet & anti-thrombotic effects of PAR4 inhibition in human blood. PAR4 inhibition impaired platelet procoagulant activity in isolated cells and during thrombosis. Our study shows PAR4 is required for platelet procoagulant function & thrombosis in human blood. SUMMARY Background Thrombin-induced platelet activation is important for arterial thrombosis. Thrombin activates human platelets predominantly via protease-activated receptor (PAR)1 and PAR4. PAR1 has higher affinity for thrombin, and the first PAR1 antagonist, vorapaxar, was recently approved for use as an antiplatelet agent. However, vorapaxar is contraindicated in a significant number of patients, owing to adverse bleeding events. Consequently, there is renewed interest in the role of platelet PAR4 in the setting of thrombus formation. Objectives To determine the specific antiplatelet effects of inhibiting PAR4 function during thrombus formation in human whole blood. Methods and Results We developed a rabbit polyclonal antibody against the thrombin cleavage site of PAR4, and showed it to be a highly specific inhibitor of PAR4-mediated platelet function. This function-blocking anti-PAR4 antibody was used to probe for PAR4-dependent platelet functions in human isolated platelets in the absence and presence of concomitant PAR1 inhibition. The anti-PAR4 antibody alone was sufficient to abolish the sustained elevation of cytosolic calcium level and consequent phosphatidylserine exposure induced by thrombin, but did not significantly inhibit integrin αII b β3 activation, α-granule secretion, or aggregation. In accord with these in vitro experiments on isolated platelets, selective inhibition of PAR4, but not of PAR1, impaired thrombin activity (fluorescence resonance energy transfer-based thrombin sensor) and fibrin formation (anti-fibrin antibody) in an ex vivo whole blood flow thrombosis assay. Conclusions These findings demonstrate that PAR4 is required for platelet procoagulant function during thrombus formation in human blood, and suggest PAR4 inhibition as a potential target for the prevention of arterial thrombosis.
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Affiliation(s)
- S L French
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
| | - J F Arthur
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
| | - H Lee
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
| | - W S Nesbitt
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
- Microplatforms Research Group, School of Engineering, RMIT University, Melbourne, Australia
| | - R K Andrews
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
| | - E E Gardiner
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
| | - J R Hamilton
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
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11
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Jayakumar T, Yang CH, Geraldine P, Yen TL, Sheu JR. The pharmacodynamics of antiplatelet compounds in thrombosis treatment. Expert Opin Drug Metab Toxicol 2016; 12:615-32. [DOI: 10.1080/17425255.2016.1176141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Thanasekaran Jayakumar
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chih-Hao Yang
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Pitchairaj Geraldine
- Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, India
| | - Ting-Lin Yen
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | - Joen-Rong Sheu
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- College of Medicine, Taipei Medical University, Taipei, Taiwan
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12
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Antithrombotic and antidiabetic flavonoid glycosides from the grains of Sorghum bicolor (L.) Moench var. hwanggeumchal. Arch Pharm Res 2014; 37:1394-402. [PMID: 24957980 DOI: 10.1007/s12272-014-0422-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 05/25/2014] [Indexed: 10/25/2022]
Abstract
A phytochemical study of the grains of S. bicolor, resulting in the isolation of twelve flavonoid glycosides 1-12. Their chemical structures were elucidated on the basis of spectroscopic (1D and 2D NMR) and MS data analyses. All compounds were tested on thrombin time (TT) assay and α-glucosidase assay in order to assess their inhibitory effects on blood coagulation and α-glucosidase enzyme. At the concentration of 500 μg/mL, compounds 3, 4, 7 and 10 possessed the potential effects on blood coagulation with inhibitory percentage of 197, 152, 120 and 158 %, respectively, whereas aspirin, which used as a positive control, indicated 181 and 138 % inhibition at 500 and 375 μg/mL, respectively. Furthermore, compounds 3, 4, 7, 9 and 10 also displayed strong inhibitory effects on α-glucosidase enzyme, with 85.2, 55.7, 43.9, 52.7 and 65.2 % inhibition at 100 μg/mL, respectively, whereas acarbose, as a positive control, possessed only 38.7 % at the same concentration. Taken together, our data suggest that S. bicolor and its flavonoid-enrich extracts could be considered as supplemental and or functional foods having beneficial effects against blood coagulation-induced ischemia, possibly thromboembolism disease, as well as diabetes.
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13
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Sidhu TS, French SL, Hamilton JR. Differential signaling by protease-activated receptors: implications for therapeutic targeting. Int J Mol Sci 2014; 15:6169-83. [PMID: 24733067 PMCID: PMC4013622 DOI: 10.3390/ijms15046169] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/14/2014] [Accepted: 04/03/2014] [Indexed: 12/29/2022] Open
Abstract
Protease-activated receptors (PARs) are a family of four G protein-coupled receptors that exhibit increasingly appreciated differences in signaling and regulation both within and between the receptor class. By nature of their proteolytic self-activation mechanism, PARs have unique processes of receptor activation, "ligand" binding, and desensitization/resensitization. These distinctive aspects have presented both challenges and opportunities in the targeting of PARs for therapeutic benefit-the most notable example of which is inhibition of PAR1 on platelets for the prevention of arterial thrombosis. However, more recent studies have uncovered further distinguishing features of PAR-mediated signaling, revealing mechanisms by which identical proteases elicit distinct effects in the same cell, as well as how distinct proteases produce different cellular consequences via the same receptor. Here we review this differential signaling by PARs, highlight how important distinctions between PAR1 and PAR4 are impacting on the progress of a new class of anti-thrombotic drugs, and discuss how these more recent insights into PAR signaling may present further opportunities for manipulating PAR activation and signaling in the development of novel therapies.
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Affiliation(s)
- Tejminder S Sidhu
- Australian Centre for Blood Diseases & Department of Clinical Haematology, Monash University, Melbourne 3004, Australia.
| | - Shauna L French
- Australian Centre for Blood Diseases & Department of Clinical Haematology, Monash University, Melbourne 3004, Australia.
| | - Justin R Hamilton
- Australian Centre for Blood Diseases & Department of Clinical Haematology, Monash University, Melbourne 3004, Australia.
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14
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Costopoulos C, Niespialowska-Steuden M, Kukreja N, Gorog DA. Novel oral anticoagulants in acute coronary syndrome. Int J Cardiol 2013; 167:2449-55. [DOI: 10.1016/j.ijcard.2012.08.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 07/18/2012] [Accepted: 08/21/2012] [Indexed: 11/16/2022]
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Denas G, Pengo V. Investigational anticoagulants for hematological conditions: a new generation of therapies. Expert Opin Investig Drugs 2013; 22:1281-94. [PMID: 23876036 DOI: 10.1517/13543784.2013.821463] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The introduction of novel anticoagulants has had contrasting effects on the agents in the pipeline, fueling the development of some and sinking the others. The complexity of the coagulation cascade offers interesting inhibition choices that might become valid treatment options. AREAS COVERED This review will highlight some of the anticoagulants in the pipeline. Following the success of the direct thrombin and FXa inhibitors already in the market, new agents are being tested. These include AZD0837, betrixaban, letaxaban, darexaban, and LY517717. Targeting other components of the hemostatic pathway might lead to better safety profiles without influencing efficacy. Inhibitors to FVIIa-tissue factor (FVIIa/TF) complex, FIX, FXI, and FXII are being assessed. New inspiring inhibitors are antisense oligonucleotides (ASOs) and aptamers. These are highly specific agents with readily reversible effect and might be engineered to inhibit any coagulation factor. Currently tested ASOs and aptamers are inhibitors of FXI, FXII, thrombin, FIXa, and platelet GPIV. EXPERT OPINION Some of the agents in the pipeline offer valid treatment option for long-term therapy, overcoming some of the drawbacks of the novel anticoagulants. Research is being driven by an expanding market in the anticoagulation field that has been unexploited for a long time.
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Affiliation(s)
- Gentian Denas
- Padua University Hospital, Cardiology Clinic, Department of Cardiac, Thoracic, and Vascular Sciences , Via Giustiniani 2, 35128 Padova , Italy +390498215658 ; +390498215658 ;
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16
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Aziz A, Aziz S, Wheatcroft SB. Novel anti-thrombotic therapy in acute coronary syndromes. COR ET VASA 2013. [DOI: 10.1016/j.crvasa.2013.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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17
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Lee H, Sturgeon SA, Mountford JK, Jackson SP, Hamilton JR. Safety and efficacy of targeting platelet proteinase-activated receptors in combination with existing anti-platelet drugs as antithrombotics in mice. Br J Pharmacol 2012; 166:2188-97. [PMID: 22428607 DOI: 10.1111/j.1476-5381.2012.01944.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Developing novel anti-platelet strategies is fundamental to reducing the impact of thrombotic diseases. Thrombin activates platelets via proteinase-activated receptors (PARs), and PAR antagonists are being evaluated in clinical trials for prevention of arterial thrombosis. However, one such trial was recently suspended due to increased bleeding in patients receiving a PAR₁ antagonist in addition to anti-platelet drugs that most often included both aspirin and clopidogrel. Therefore, it remains unclear how to best manipulate PARs for safe antithrombotic activity. To address this, we have examined potential interactions between existing anti-platelet drugs and strategies that target PARs. EXPERIMENTAL APPROACH We used in vivo mouse models in which interactions between various anti-platelet strategies could be evaluated. We examined the effects on thrombosis and haemostasis in PAR₄ -/- mice (platelets unresponsive to thrombin) treated with therapeutic doses of either aspirin or clopidogrel. KEY RESULTS Using a model in which occlusive thrombosis occurred in PAR₄ -/- mice or wild-type mice treated with aspirin or clopidogrel, PAR₄ -/- mice treated with either anti-platelet agent showed marked protection against thrombosis. This antithrombotic effect occurred without any effect on haemostasis with aspirin, but not clopidogrel. Furthermore, specifically targeting thrombin-induced platelet activation (via PARs) improved the therapeutic window of non-specifically inhibiting thrombin functions (via anticoagulants). CONCLUSIONS AND IMPLICATIONS Our results indicate that PAR antagonists used in combination with aspirin provide a potent yet safe antithrombotic strategy in mice and provide insights into the safety and efficacy of using PAR antagonists for the prevention of acute coronary syndromes in humans.
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Affiliation(s)
- H Lee
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
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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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Marchant DJ, Boyd JH, Lin DC, Granville DJ, Garmaroudi FS, McManus BM. Inflammation in myocardial diseases. Circ Res 2012; 110:126-44. [PMID: 22223210 DOI: 10.1161/circresaha.111.243170] [Citation(s) in RCA: 215] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Inflammatory processes underlie a broad spectrum of conditions that injure the heart muscle and cause both structural and functional deficits. In this article, we address current knowledge regarding 4 common forms of myocardial inflammation: myocardial ischemia and reperfusion, sepsis, viral myocarditis, and immune rejection. Each of these pathological states has its own unique features in pathogenesis and disease evolution, but all reflect inflammatory mechanisms that are partially shared. From the point of injury to the mobilization of innate and adaptive immune responses and inflammatory amplification, the cellular and soluble mediators and mechanisms examined in this review will be discussed with a view that both beneficial and adverse consequences arise in these human conditions.
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Affiliation(s)
- David J Marchant
- James Hogg Research Centre and Institute for Heart + Lung Health, Department of Pathology and Laboratory Medicine, University of British Columbia, Providence Health Care, Vancouver, Canada
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Abstract
Vascular endothelium is a key regulator of homeostasis. In physiological conditions it mediates vascular dilatation, prevents platelet adhesion, and inhibits thrombin generation. However, endothelial dysfunction caused by physical injury of the vascular wall, for example during balloon angioplasty, acute or chronic inflammation, such as in atherothrombosis, creates a proinflammatory environment which supports leukocyte transmigration toward inflammatory sites. At the same time, the dysfunction promotes thrombin generation, fibrin deposition, and coagulation. The serine protease thrombin plays a pivotal role in the coagulation cascade. However, thrombin is not only the key effector of coagulation cascade; it also plays a significant role in inflammatory diseases. It shows an array of effects on endothelial cells, vascular smooth muscle cells, monocytes, and platelets, all of which participate in the vascular pathophysiology such as atherothrombosis. Therefore, thrombin can be considered as an important modulatory molecule of vascular homeostasis. This review summarizes the existing evidence on the role of thrombin in vascular inflammation.
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Cirino G, Severino B. Thrombin receptors and their antagonists: an update on the patent literature. Expert Opin Ther Pat 2010; 20:875-84. [PMID: 20450349 DOI: 10.1517/13543776.2010.487864] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
IMPORTANCE OF THE FIELD Thrombin plays a central role in cardiovascular inflammation. Most of the cellular responses to thrombin are mediated by cell surface protease-activated receptors (PARs). Several preclinical studies indicate that PARs are potential targets for treating cardiovascular diseases such as thrombosis, atherosclerosis and restenosis. Among PARs, PAR-1 has emerged as an important therapeutic target. AREAS COVERED IN THIS REVIEW This review covers recent advances in the development of thrombin receptors antagonists. It is focused on the search for PAR-1 antagonists as this is at the moment the most promising and attractive target. However, some early promising studies on PAR-3 and -4 antagonists are also reported. WHAT THE READER WILL GAIN The review has been written in order to give to the reader hints and references that cover, in our opinion, the most interesting and/or promising approaches in this research field. TAKE HOME MESSAGE Research on PAR-1 antagonists has finally led to good clinical candidates such as SCH-530348 (Schering-Plough) and E-5555 (Eisai Co.). Clinical trials clearly demonstrate that development of PAR1 antagonists is not only possible but most likely will lead to development of antiplatelet drugs as well as of drugs useful for the treatment of inflammatory, proliferative and neurodegenerative diseases.
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Affiliation(s)
- Giuseppe Cirino
- University of Naples Federico II, Department of Experimental Pharmacology, Via Domenico Montesano 49, Napoli 80131, Italy.
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Dharmarajah J, Arthur JF, Sobey CG, Drummond GR. The anti-platelet effects of apocynin in mice are not mediated by inhibition of NADPH oxidase activity. Naunyn Schmiedebergs Arch Pharmacol 2010; 382:377-84. [PMID: 20809239 DOI: 10.1007/s00210-010-0552-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 08/12/2010] [Indexed: 11/27/2022]
Abstract
Apocynin, or a (myelo)peroxidase-derived product thereof, is a powerful inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Apocynin has also been shown to prevent aggregation of platelets in response to agonists such as collagen and thrombin. The aims of this study were to establish whether NADPH oxidase activity is required for aggregation of murine platelets to collagen and other agonists and whether the anti-aggregatory effects of apocynin are due to an inhibitory action against this enzyme. Washed platelets were isolated from male C57BL6 (wild-type), Nox2-deficient (Nox2(-/y )), and p47phox-deficient (p47phox(-/-)) mice for assessment of aggregation and NADPH oxidase subunit (Nox2, p47phox) expression. Collagen and U46619 elicited aggregation of murine platelets, and these responses were inhibited by apocynin at concentrations ≥100 μM. By contrast, aggregations to a direct protein kinase C activator, phorbol-12,13-dibutyrate, were insensitive to apocynin. Immunoblotting of platelet protein homogenates from wild-type mice with anti-Nox2 or p47phox antibodies revealed strong bands at 58 and 50 kDa, respectively. While expression of these immunoreactive bands was greatly diminished in platelets from Nox2(-/y ) and p47phox(-/-) mice, collagen still elicited aggregations that were similar to those observed in platelets from wild-types. Moreover, apocynin was an equally effective inhibitor of aggregation in platelets from all three mouse strains. In conclusion, these data suggest that NADPH oxidase-derived reactive oxygen species play no role in the aggregation response of washed murine platelets to collagen. Thus, our observation that apocynin is a powerful inhibitor of platelet aggregation raises further questions about the selectivity of this drug as an NADPH oxidase inhibitor.
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Goto S, Ogawa H, Takeuchi M, Flather MD, Bhatt DL. Double-blind, placebo-controlled Phase II studies of the protease-activated receptor 1 antagonist E5555 (atopaxar) in Japanese patients with acute coronary syndrome or high-risk coronary artery disease. Eur Heart J 2010; 31:2601-13. [PMID: 20805115 PMCID: PMC2966970 DOI: 10.1093/eurheartj/ehq320] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Aims Two multicentre, randomized, double-blind, placebo-controlled Phase II studies assessed the safety and efficacy of the oral protease-activated receptor 1 (PAR-1) antagonist E5555 in addition to standard therapy in Japanese patients with acute coronary syndrome (ACS) or high-risk coronary artery disease (CAD). Methods and results Patients with ACS (n = 241) or high-risk CAD (n = 263) received E5555 (50, 100, or 200 mg) or placebo once daily for 12 (ACS patients) or 24 weeks (CAD patients). The incidence of TIMI major, minor, and minimal bleeds requiring medical attention was similar in the placebo and combined E5555 (atopaxar) groups (ACS: 6.6% placebo vs. 5.0% E5555; CAD: 1.5% placebo vs. 1.5% E5555). There were no TIMI major bleeds and three CURE major bleeds (two with placebo; one with 100 mg E5555). There was a numerical increase in ‘any’ TIMI bleeding with the E5555 200 mg dose (ACS: 16.4% placebo vs. 23.0% E5555, P = 0.398; CAD: 4.5% placebo vs. 13.2% E5555, P = 0.081). The rate of major cardiovascular adverse events in the combined E5555 group was not different from placebo (ACS: 6.6% placebo vs. 5.0% E5555, P = 0.73; CAD: 4.5% placebo vs. 1.0% E5555, P = 0.066). There was a statistically significant dose-dependent increase in liver function abnormalities and QTcF with E5555. At trough dosing levels in both populations, mean inhibition of platelet aggregation was >90% with 100 and 200 mg E5555, and 20–60% with 50 mg E5555. Conclusion E5555 (50, 100, and 200 mg) did not increase clinically significant bleeding, although there was a higher rate of any TIMI bleeding with the highest two doses. All doses tested achieved a significant level of platelet inhibition. There was a significant dose-dependent increase in liver function abnormalities and QTcF. Although further study is needed, PAR-1 antagonism may have the potential to be a novel pathway for platelet inhibition to add on to the current standard of care therapy.
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Affiliation(s)
- Shinya Goto
- Department of Medicine (Cardiology), Tokai University School of Medicine, Isehara, Kanagawa 259-1143, Japan.
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Girnys EA, Sobczyk-Kojiro K, Mosberg HI. Structure-based design of residue 1 analogs of the direct thrombin inhibitor pentapeptide FM 19. Chem Biol Drug Des 2010; 75:35-9. [PMID: 19954432 DOI: 10.1111/j.1747-0285.2009.00915.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Myocardial ischemia and other acute coronary syndromes are leading causes of death worldwide, and often result from a thrombus that blocks an atherosclerotic coronary artery. A key enzyme in thrombus formation is the serine protease thrombin, which is responsible for both the conversion of soluble fibrinogen into insoluble fibrin, as well as the activation of the GPCRs, PAR1 and PAR4, which stimulate platelet aggregation. Thus, thrombin is an attractive target for anticoagulant and antithrombotic therapy. Previous studies in our laboratory led to the development of lead compound FM 19 (D-Arg-Oic-Pro-D-Ala-Phe(p-Me)-NH2), which shows modest potency as a thrombin inhibitor. The recently determined X-ray structure of FM 19 in the active site of thrombin has revealed potential sites for modification to improve potency. This study reports replacements to the first residue (D-Arg1) of FM 19, which seek to improve potency by removing the N-terminal amine to eliminate an adverse electrostatic interaction, and alterations to the length of the side chain to eliminate an unfavorable eclipsed conformation observed in the X-ray structure. This study produced two compounds, 1 and 9, with improved alpha-thrombin inhibition (IC50 values of 0.66 +/- 0.20 microM and 0.57 +/- 0.12 microM, respectively).
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Affiliation(s)
- Elizabeth A Girnys
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109-1065, USA
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Wu HM, Xu L, Sedmak DD, Marsh CB, Wurster MW. Personalized healthcare in clotting disorders. Per Med 2010; 7:65-73. [DOI: 10.2217/pme.09.67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In terms of managing thrombotic disorders, genotype-based individualized patient care emerged as early as 1994 when the association of factor V Leiden (G1691A), and later, prothrombin (G20210A), with thrombotic phenotypes were discovered. Since then, genetic tests for specific thrombophilic SNPs have been routinely incorporated into daily practices in both thrombotic risk assessment and clinical decision-making with respect to prophylactic anti-thrombotic therapy. Recently, the area of pharmacogenomics in major anti-thrombotic drugs, such as warfarin and clopidogrel, has been the principal driver for personalized therapy based on one’s own individual characteristics.
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Affiliation(s)
- Haifeng M Wu
- Clinical Coagulation Laboratory, Departments of Pathology and Internal Medicine, Ohio State University College of Medicine, 164 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USA
| | - LiHui Xu
- Clinical Coagulation Laboratory, Departments of Pathology and Internal Medicine, Ohio State University College of Medicine, 164 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USA
| | - Daniel D Sedmak
- Clinical Coagulation Laboratory, Departments of Pathology and Internal Medicine, Ohio State University College of Medicine, 164 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USA
| | - Clay B Marsh
- Clinical Coagulation Laboratory, Departments of Pathology and Internal Medicine, Ohio State University College of Medicine, 164 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USA
| | - Mark W Wurster
- Clinical Coagulation Laboratory, Departments of Pathology and Internal Medicine, Ohio State University College of Medicine, 164 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, 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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