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Back V, Asgari A, Franczak A, Saito M, Castaneda Zaragoza D, Sandow SL, Plane F, Jurasz P. Inhibition of platelet aggregation by activation of platelet intermediate conductance Ca 2+ -activated potassium channels. J Thromb Haemost 2022; 20:2587-2600. [PMID: 35867883 DOI: 10.1111/jth.15827] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 07/05/2022] [Accepted: 07/11/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND Within the vasculature platelets and endothelial cells play crucial roles in hemostasis and thrombosis. Platelets, like endothelial cells, possess intermediate conductance Ca2+ -activated K+ (IKCa ) channels and generate nitric oxide (NO). Although NO limits platelet aggregation, the role of IKCa channels in platelet function and NO generation has not yet been explored. OBJECTIVES We investigated whether IKCa channel activation inhibits platelet aggregation, and per endothelial cells, enhances platelet NO production. METHODS Platelets were isolated from human volunteers. Aggregometry, confocal microscopy, and a novel flow chamber model, the Quartz Crystal Microbalance (QCM) were used to assess platelet function. Flow cytometry was used to measure platelet NO production, calcium signaling, membrane potential, integrin αIIb /β3 activation, granule release, and procoagulant platelet formation. RESULTS Platelet IKCa channel activation with SKA-31 inhibited aggregation in a concentration-dependent manner, an effect reversed by the selective IKCa channel blocker TRAM-34. The QCM model along with confocal microscopy demonstrated that SKA-31 inhibited platelet aggregation under flow conditions. Surprisingly, IKCa activation by SKA-31 inhibited platelet NO generation, but this could be explained by a concomitant reduction in platelet calcium signaling. IKCa activation by SKA-31 also inhibited dense and alpha-granule secretion and integrin αIIb /β3 activation, but maintained platelet phosphatidylserine surface exposure as a measure of procoagulant response. CONCLUSIONS Platelet IKCa channel activation inhibits aggregation by reducing calcium-signaling and granule secretion, but not by enhancing platelet NO generation. IKCa channels may be novel targets for the development of antiplatelet drugs that limit atherothrombosis, but not coagulation.
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Affiliation(s)
- Valentina Back
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Amir Asgari
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Aleksandra Franczak
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Max Saito
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Diego Castaneda Zaragoza
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Shaun L Sandow
- Biomedical Sciences, University of the Sunshine Coast, Sydney, Queensland, Australia
- Department of Physiology, University of New South Wales, Sydney, Queensland, Australia
| | - Frances Plane
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada
| | - Paul Jurasz
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada
- Mazankowski Alberta Heart Institute, Edmonton, Alberta, Canada
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2
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Methane-Rich Saline Protects Against Sepsis-Induced Liver Damage by Regulating the PPAR-γ/NF-κB Signaling Pathway. Shock 2020; 52:e163-e172. [PMID: 30601406 DOI: 10.1097/shk.0000000000001310] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Sepsis, a life-threatening organ dysfunction due to a dysregulated response to infection, is a common complication of major surgery. Previous studies have shown that methane possesses protective properties. This study aims to investigate the protective effect of methane-rich saline (MRS) on sepsis-induced liver injury. In an in vivo experiment, C57BL/6 mice received cecal ligation and puncture to create a septic model followed by MRS treatment (10 mL/kg, ip treatment) 30 min and 12 h after the operation. We found that methane effectively decreased the serum aspartate aminotransferase, alanine aminotransferase and liver index, as well as the liver pathological damage, and reduced the localized infiltration of inflammatory cells. Methane suppressed the expression of the toll-like receptor 4/nuclear factor-kappa B (NF-κB) signaling pathway and stimulated the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) during sepsis, which inhibited the activation of NF-κB and decreased the level of inflammatory cytokines, such as tumor necrosis factor-α, interleukin-6, and interleukin-1β. Moreover, we found that MRS treatment relieved reactive oxygen species (ROS) damage by upregulating heme oxygenase-1, superoxide dismutase and glutathione, and downregulating malondialdehyde, which was consistent with the results of dihydroethidium fluorescent staining. MRS treatment also regulated apoptosis-related proteins, such as Bax, Bcl-2, and caspase-3. In the in vitro experiment, HepG2 cells received inflammatory stimulation induced by LPS followed by methane-rich medium (MRM) treatment. We found that MRM alleviated the inflammatory damage, ROS damage and regulated the expression of PPAR-γ/NF-κB. Our data indicated that methane treatment prevented liver damage in sepsis via anti-inflammatory, anti-oxidative, and anti-apoptotic properties that involved the PPAR-γ/ NF-κB signaling pathway.
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Kojok K, El-Kadiry AEH, Merhi Y. Role of NF-κB in Platelet Function. Int J Mol Sci 2019; 20:E4185. [PMID: 31461836 PMCID: PMC6747346 DOI: 10.3390/ijms20174185] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 08/25/2019] [Accepted: 08/26/2019] [Indexed: 01/04/2023] Open
Abstract
Platelets are megakaryocyte-derived fragments lacking nuclei and prepped to maintain primary hemostasis by initiating blood clots on injured vascular endothelia. Pathologically, platelets undergo the same physiological processes of activation, secretion, and aggregation yet with such pronouncedness that they orchestrate and make headway the progression of atherothrombotic diseases not only through clot formation but also via forcing a pro-inflammatory state. Indeed, nuclear factor-κB (NF-κB) is largely implicated in atherosclerosis and its pathological complication in atherothrombotic diseases due to its transcriptional role in maintaining pro-survival and pro-inflammatory states in vascular and blood cells. On the other hand, we know little on the functions of platelet NF-κB, which seems to function in other non-genomic ways to modulate atherothrombosis. Therein, this review will resemble a rich portfolio for NF-κB in platelets, specifically showing its implications at the levels of platelet survival and function. We will also share the knowledge thus far on the effects of active ingredients on NF-κB in general, as an extrapolative method to highlight the potential therapeutic targeting of NF-κB in coronary diseases. Finally, we will unzip a new horizon on a possible extra-platelet role of platelet NF-κB, which will better expand our knowledge on the etiology and pathophysiology of atherothrombosis.
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Affiliation(s)
- Kevin Kojok
- The Laboratory of Thrombosis and Hemostasis, Montreal Heart Institute, Research Centre, 5000 Belanger Street, Montreal, H1T 1C8, QC, Canada
- Faculty of Medicine, Université de Montréal, Montreal, H3T 1J4, QC, Canada
| | - Abed El-Hakim El-Kadiry
- The Laboratory of Thrombosis and Hemostasis, Montreal Heart Institute, Research Centre, 5000 Belanger Street, Montreal, H1T 1C8, QC, Canada
- Faculty of Medicine, Université de Montréal, Montreal, H3T 1J4, QC, Canada
| | - Yahye Merhi
- The Laboratory of Thrombosis and Hemostasis, Montreal Heart Institute, Research Centre, 5000 Belanger Street, Montreal, H1T 1C8, QC, Canada.
- Faculty of Medicine, Université de Montréal, Montreal, H3T 1J4, QC, Canada.
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Hsu CY, Huang LY, Saver JL, Wu YL, Lee JD, Chen PC, Lee M, Ovbiagele B. Oral short-acting antihypertensive medications and the occurrence of stroke: a nationwide case-crossover study. Hypertens Res 2019; 42:1794-1800. [PMID: 31300722 DOI: 10.1038/s41440-019-0300-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 05/19/2019] [Accepted: 06/06/2019] [Indexed: 12/16/2022]
Abstract
The purpose of the study was to clarify whether short-acting antihypertensives are associated with the occurrence of ischemic stroke and intracerebral hemorrhage (ICH). This was a retrospective case-crossover study using the Taiwan National Health Insurance Research Database. We identified all adult patients hospitalized with a primary diagnosis of ischemic stroke or ICH between January 2005 and December 2013. For each case, short-term and long-term exposure to short-acting antihypertensives, including nifedipine, labetalol and captopril, during the case vs. control periods were compared, and odd ratios (ORs) and 95% confidence intervals (CIs) for ischemic stroke or ICH were calculated with adjustment for confounders. Among 272785 ischemic stroke and 77798 ICH patients, the mean age was 77.8 ± 14.3 years and 70.8 ± 16.6 years, respectively. The short-term use of the three short-acting antihypertensives were all associated with an increase in the incidence of ischemic stroke (nifedipine: OR 4.51, 95% CIs 3.99-5.11; labetalol: OR 2.07; 95% CIs 1.71-2.51; captopril: OR 1.98, 95% CIs 1.72-2.29) and ICH (nifedipine: OR 2.98, 95% CIs 2.30-3.84; labetalol: OR 2.37; 95% CIs 1.66-3.39; captopril: OR 2.48; 95% CIs 1.69-3.63). The long-term use of short-acting nifedipine for 30 days was associated with a modest increase in the risk for ischemic stroke (OR 1.86; 95% CIs 1.42-2.45). Overall, the short-term use of short-acting antihypertensives is associated with a modest increase in the incidence of stroke, and short-acting nifedipine is linked to a substantial rise in the incidence of ischemic stroke. The long-term use of short-acting nifedipine was also related to an increased incidence of ischemic stroke. Physicians should be cautious of prescribing these short-acting antihypertensives.
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Affiliation(s)
- Chia-Yu Hsu
- Department of Neurology, Chang Gung University College of Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan
| | - Ling-Ya Huang
- School of Pharmacy, National Taiwan University, Chiayi, Taiwan
| | - Jeffrey L Saver
- Stroke Center and Department of Neurology, Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Yi-Ling Wu
- Research Services Center for Health Information, Chang Gung University, Taoyuan, Taiwan
| | - Jiann-Der Lee
- Department of Neurology, Chang Gung University College of Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan
| | - Pei-Chun Chen
- Department of Public Health, China Medical University, Taoyuan, Taiwan
| | - Meng Lee
- Department of Neurology, Chang Gung University College of Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan.
| | - Bruce Ovbiagele
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA
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Braschi A. Potential Protective Role of Blood Pressure-Lowering Drugs on the Balance between Hemostasis and Fibrinolysis in Hypertensive Patients at Rest and During Exercise. Am J Cardiovasc Drugs 2019; 19:133-171. [PMID: 30714087 DOI: 10.1007/s40256-018-00316-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In patients with hypertension, the triad represented by endothelial dysfunction, platelet hyperactivity, and altered fibrinolytic function disturbs the equilibrium between hemostasis and fibrinolysis and translates into a hypercoagulable state, which underlies the risk of thrombotic complications. This article reviews the scientific evidence regarding some biological effects of antihypertensive drugs, which can protect patients from the adverse consequences of hypertensive disease, improving endothelial function, enhancing antioxidant activity, and restoring equilibrium between hemostatic and fibrinolytic factors. These protective effects appear not to be mediated through blood pressure reduction and are not shared by all molecules of the same pharmacological class.
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Affiliation(s)
- Annabella Braschi
- Ambulatory of Cardiovascular Diseases, Via col. Romey n.10, 91100, Trapani, Italy.
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Muñoz-Gutiérrez C, Sepúlveda C, Caballero J, Palomo I, Fuentes E. Study of the interactions between Edaglitazone and Ciglitazone with PPARγ and their antiplatelet profile. Life Sci 2017; 186:59-65. [PMID: 28757415 DOI: 10.1016/j.lfs.2017.07.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/26/2017] [Accepted: 07/27/2017] [Indexed: 12/27/2022]
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcription factor with an important role in lipid metabolism, inflammation and cardiovascular diseases. PPARγ ligands have inhibitory effects on platelet aggregation via the cAMP pathway, which may confer them a protective cardioprotective role. Edaglitazone and Ciglitazone are two chemically-similar thiazolidinedione (TZD) drugs that have been described as potent PPARγ agonists; however, Edaglitazone is over 100 times more potent than Ciglitazone. Here, we report a computational study to describe the ligand binding and the experimental antiplatelet profiles of Edaglitazone and Ciglitazone. Both ligands presented similar orientations within the PPARγ binding site. Their polar heads exhibit complex hydrogen bond networks with the residues at arm I pocket, while their hydrophobic tails are oriented inside arm II or the entrance pocket. The bulkier and longer tail of Edaglitazone exhibited additional hydrophobic interactions, explaining its stronger binding to PPARγ supported by binding affinity calculations. On the other hand, both Edaglitazone and Ciglitazone displayed an antiplatelet activity, but only Edaglitazone retained such effect at low concentrations. Furthermore, we evidenced that Edaglitazone increases intraplatelet cAMP levels and prevents PPARγ secretion, explaining its greater antiplatelet activity. Altogether, the more potent PPARγ agonist Edaglitazone seems to be a potent antiplatelet agent.
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Affiliation(s)
- Camila Muñoz-Gutiérrez
- Centro de Bioinformática y Simulación Molecular (CBSM), Universidad de Talca, Talca, Chile
| | - Cesar Sepúlveda
- Platelet Research Center, Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), Universidad de Talca, Talca, Chile
| | - Julio Caballero
- Centro de Bioinformática y Simulación Molecular (CBSM), Universidad de Talca, Talca, Chile.
| | - Iván Palomo
- Platelet Research Center, Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), Universidad de Talca, Talca, Chile
| | - Eduardo Fuentes
- Platelet Research Center, Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), Universidad de Talca, Talca, Chile; Núcleo Científico Multidisciplinario, Universidad de Talca, Talca, Chile.
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7
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Sepúlveda C, Palomo I, Fuentes E. Antiplatelet activity of drugs used in hypertension, dyslipidemia and diabetes: Additional benefit in cardiovascular diseases prevention. Vascul Pharmacol 2017; 91:10-17. [DOI: 10.1016/j.vph.2017.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 02/03/2017] [Accepted: 03/21/2017] [Indexed: 02/02/2023]
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8
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The synthetic ajoene analog SPA3015 induces apoptotic cell death through crosstalk between NF-κB and PPARγ in multidrug-resistant cancer cells. Food Chem Toxicol 2016; 96:35-42. [DOI: 10.1016/j.fct.2016.07.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 07/15/2016] [Accepted: 07/19/2016] [Indexed: 01/28/2023]
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9
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Fuentes E, Rojas A, Palomo I. NF-κB signaling pathway as target for antiplatelet activity. Blood Rev 2016; 30:309-15. [PMID: 27075489 DOI: 10.1016/j.blre.2016.03.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 02/26/2016] [Accepted: 03/08/2016] [Indexed: 02/07/2023]
Abstract
In different nucleated cells, NF-κB has long been considered a prototypical proinflammatory signaling pathway with the expression of proinflammatory genes. Although platelets lack a nucleus, a number of functional transcription factors are involved in activated platelets, such as NF-κB. In platelet activation NF-κB regulation events include IKKβ phosphorylation, IκBα degradation, and p65 phosphorylation. Multiple pathways contribute to platelet activation and NF-κB is a common pathway in this activation. Therefore, in platelet activation the modulation of NF-κB pathway could be a potential new target in the treatment of inflammation-related vascular disease therapy (antiplatelet and antithrombotic activities).
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Affiliation(s)
- Eduardo Fuentes
- Laboratory of Hematology and Immunology, Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), Universidad de Talca, Talca, Chile; Centro de Estudios en Alimentos Procesados (CEAP), CONICYT-Regional, Gore Maule, R09I2001, Talca, Chile.
| | - Armando Rojas
- Biomedical Research Laboratories, Medicine Faculty, Catholic University of Maule, Talca, Chile
| | - Iván Palomo
- Laboratory of Hematology and Immunology, Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), Universidad de Talca, Talca, Chile; Centro de Estudios en Alimentos Procesados (CEAP), CONICYT-Regional, Gore Maule, R09I2001, Talca, Chile.
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Abstract
Antiplatelet agents represent a cornerstone in the management of patients at increased cardiovascular risk. Essential hypertension is considered a major public health problem leading to increased cardiovascular morbidity and mortality. The majority of patients with essential hypertension exhibit also additional cardiovascular risk factors and present with increased platelet activation. Despite recent innovations in the field of antiplatelet treatment and the introduction of novel agents, the role of antiplatelet treatment in patients with essential hypertension remains understudied. This review aims to shed light on novel experimental and clinical data in the evolving field of antiplatelet treatment in essential hypertension. In particular, recent data regarding aspirin, clopidogrel, novel P2Y12 inhibitors, and other agents with potential antiplatelet effects are critically reviewed.
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Chen TH, Shih CY, Hsu WL, Chou TC. Mechanisms of Nifedipine-Downregulated CD40L/sCD40L Signaling in Collagen Stimulated Human Platelets. PLoS One 2015; 10:e0127054. [PMID: 25970603 PMCID: PMC4430314 DOI: 10.1371/journal.pone.0127054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 04/10/2015] [Indexed: 01/19/2023] Open
Abstract
The platelet-derived soluble CD40L (sCD40L) release plays a critical role in the development of atherosclerosis. Nifedipine, a dihydropyridine-based L-type calcium channel blocker (CCB), has been reported to have an anti-atherosclerotic effect beyond its blood pressure-lowering effect, but the molecular mechanisms remain unclear. The present study was designed to investigate whether nifedipine affects sCD40L release from collagen-stimulated human platelets and to determine the potential role of peroxisome proliferator-activated receptor-β/-γ (PPAR-β/-γ). We found that treatment with nifedipine significantly inhibited the platelet surface CD40L expression and sCD40L release in response to collagen, while the inhibition was markedly reversed by blocking PPAR-β/-γ activity with specific antagonist such as GSK0660 and GW9662. Meanwhile, nifedipine also enhanced nitric oxide (NO) and cyclic GMP formation in a PPAR-β/-γ-dependent manner. When the NO/cyclic GMP pathway was suppressed, nifedipine-mediated inhibition of sCD40L release was abolished significantly. Collagen-induced phosphorylation of p38MAPK, ERK1/2 and HSP27, matrix metalloproteinase-2 (MMP-2) expression/activity and reactive oxygen species (ROS) formation were significantly inhibited by nifedipine, whereas these alterations were all attenuated by co-treatment with PPAR-β/-γ antagonists. Collectively, these results demonstrate that PPAR-β/-γ-dependent pathways contribute to nifedipine-mediated downregulation of CD40L/sCD40L signaling in activated platelets through regulation of NO/ p38MAPK/ERK1/2/HSP27/MMP-2 signalings and provide a novel mechanism regarding the anti-atherosclerotic effect of nifedipine.
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Affiliation(s)
- Tso-Hsiao Chen
- Division of Nephrology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Ching-Yu Shih
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Wen-Lin Hsu
- School of Medicine, Tzu Chi University; Department of Radiation Oncology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Tz-Chong Chou
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
- Department ofBiotechnology, Asia University, Taichung, Taiwan
- China Medical University Hospital, China Medical University, Taichung, Taiwan
- * E-mail:
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Chou TC. New mechanisms of antiplatelet activity of nifedipine, an L-type calcium channel blocker. Biomedicine (Taipei) 2014; 4:24. [PMID: 25520937 PMCID: PMC4265014 DOI: 10.7603/s40681-014-0024-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 11/05/2014] [Indexed: 01/03/2023] Open
Abstract
Platelet hyperactivity often occursd in hypertensive patients and is a key factor in the development of cardiovascular diseases including thrombosis and atherosclerosis. Nifedipine, an L-type calcium channel blocker, is widely used for hypertension and coronary heart disease therapy. In addition, nifedipine is known to exhibit an antiplatelet activity, but the underlying mechanisms involved remain unclear. Several transcription factors such as peroxisome proliferator-activated receptors (PPARs) and nuclear factor kappa B (NF-κB) exist in platelets and have an ability to regulate platelet aggregation through a non-genomic mechanism. The present article focuses on describing the mechanisms of the antiplatelet activity of nifedipine via PPAR activation. It has been demonstrated that nifedipine treatment increases the activity and intracellular amount of PPAR-β/-γ in activated platelets. Moreover, the antiplatelet activity of nifedipine is mediated by PPAR-β/-γ-dependent upon the up-regulation of the PI3K/AKT/NO/cyclic GMP/PKG pathway, and inhibition of protein kinase Cα (PKCα) activity via an interaction between PPAR-β/-γ and PKCα. Furthermore, suppressing NF-κB activation by nifedipine through enhanced association of PPAR-β/-γ with NF-κB has also been observed in collagen-stimulated platelets. Blocking PPAR-β/-γ activity or increasing NF-κB activation greatly reverses the antiplatelet activity and inhibition of intracellular Ca2+ mobilization, PKCα activity, and surface glycoprotein IIb/IIIa expression caused by nifedipine. Thus, PPAR-β/-γ- dependent suppression of NF-κB activation also contributes to the antiplatelet activity of nifedipine. Consistently, administration of nifedipine markedly reduces fluorescein sodium-induced vessel thrombus formation in mice, which is considerably inhibited when the PPAR-β/-γ antagonists are administrated simultaneously. Collectively, these results provide important information regarding the mechanism by which nifedipine inhibits platelet aggregation and thrombus formation through activation of PPAR-β/-γ- mediated signaling pathways. These findings highlight that PPARs are novel therapeutic targets for preventing and treating platelet-hyperactivity-related vascular diseases.
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Affiliation(s)
- Tz-Chong Chou
- Institute of Medical Sciences, Tzu Chi University, 6F, Xie-Li Building, No. 707, Sec. 3, Zhongyang Rd.,, 970 Hualien, Taiwan
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