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Cleary SJ, Rauzi F, Smyth E, Correia A, Hobbs C, Emerson M, Page CP, Pitchford SC. Radiolabelling and immunohistochemistry reveal platelet recruitment into lungs and platelet migration into airspaces following LPS inhalation in mice. J Pharmacol Toxicol Methods 2019; 102:106660. [PMID: 31838234 DOI: 10.1016/j.vascn.2019.106660] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/21/2019] [Accepted: 12/01/2019] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Platelets are under investigation for their role in host defence and inflammatory lung diseases and have been demonstrated to be recruited to the lung. However, the mechanisms and consequences of platelet recruitment into lungs are poorly understood. We have utilised a murine model to investigate the mechanisms of platelet involvement in lung inflammation induced by intranasal administration of LPS. OBJECTIVES Our aim was to characterise lung platelet recruitment following LPS inhalation in mice using immunohistochemistry, and non-invasive and invasive radiolabelled platelet tracking techniques. RESULTS Intranasal administration of LPS caused an increase in lung platelet staining in lung tissue and elicited the recruitment of radiolabelled platelets into the lung. Prior to these responses in the lung, we observed an earlier decrease in blood platelet counts, temporally associated with platelet recruitment to the liver and spleen. Non-invasive measurements of thoracic radioactivity reflected changes in blood counts rather than extravascular lung platelet recruitment. However, both in situ counting of radiolabelled platelets and immunostaining for platelet surface markers showed LPS-induced increases in extravascular platelets into lung airspaces suggesting that some of the platelets recruited to the lung enter air spaces. CONCLUSIONS Intranasal administration of LPS activates the innate immune response which includes a fall in peripheral blood platelet counts with subsequent platelet recruitment to the lung, spleen and liver, measured by immunohistochemistry and radiolabelling techniques.
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Affiliation(s)
- S J Cleary
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, UK
| | - F Rauzi
- National Heart & Lung Institute, Imperial College London, London, UK
| | - E Smyth
- National Heart & Lung Institute, Imperial College London, London, UK
| | - A Correia
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, UK
| | - C Hobbs
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| | - M Emerson
- National Heart & Lung Institute, Imperial College London, London, UK
| | - C P Page
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, UK
| | - S C Pitchford
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, UK.
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Taylor KA, Smyth E, Rauzi F, Cerrone M, Khawaja AA, Gazzard B, Nelson M, Boffito M, Emerson M. Pharmacological impact of antiretroviral therapy on platelet function to investigate human immunodeficiency virus-associated cardiovascular risk. Br J Pharmacol 2019; 176:879-889. [PMID: 30681136 DOI: 10.1111/bph.14589] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/20/2018] [Accepted: 12/14/2018] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND PURPOSE Some clinical studies have reported increased myocardial infarction in people living with human immunodeficiency virus (HIV) taking the antiretroviral abacavir sulphate (ABC). Given that clinical studies contain confounding variables (e.g., HIV-associated factors), we investigated the pharmacological effects of antiretrovirals on platelet function in HIV-negative volunteers in order to identify mechanisms of increased cardiovascular risk. EXPERIMENTAL APPROACH Platelets were isolated from healthy volunteers and HIV-negative subjects enrolled on a Phase I clinical trial and platelet function evaluated using aggregometry and flow cytometry. In vivo platelet thromboembolism was monitored in anaesthetized mice. KEY RESULTS Human platelet aggregation was unaffected by all antiretrovirals tested, but ABC treatment led uniquely to increased platelet granule release. ABC also interrupted NO-mediated inhibition of platelet aggregation and increased in vivo aggregation in mice. Another antiretroviral, tenofovir, did not affect platelet function. Furthermore, aggregation and activation of platelets isolated from 20 subjects taking clinically relevant doses of tenofovir were comparable to baseline samples. CONCLUSIONS AND IMPLICATIONS ABC can enhance platelet activation, independently of variables that confound clinical studies, suggesting a potential pharmacological effect that is absent with tenofovir. Mechanistically, we propose that ABC enhances platelet degranulation and interrupts NO-mediated platelet inhibition. The interaction of ABC with NO signalling is demonstrated by ABC-mediated enhancement of aggregation in vivo and in vitro that persisted in the presence of NO. Although an association between ABC and platelet activation has not been confirmed in patients, these findings provide evidence of a mechanistic link between platelet activation and antiretroviral therapy.
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Affiliation(s)
- Kirk A Taylor
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Erica Smyth
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Francesca Rauzi
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Maddalena Cerrone
- Department of HIV and Genitourinary Medicine, Chelsea and Westminster NHS Foundation Trust, London, UK
| | - Akif A Khawaja
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Brian Gazzard
- Department of HIV and Genitourinary Medicine, Chelsea and Westminster NHS Foundation Trust, London, UK
| | - Mark Nelson
- Department of Medicine, Imperial College London, London, UK.,Department of HIV and Genitourinary Medicine, Chelsea and Westminster NHS Foundation Trust, London, UK
| | - Marta Boffito
- Department of Medicine, Imperial College London, London, UK.,Department of HIV and Genitourinary Medicine, Chelsea and Westminster NHS Foundation Trust, London, UK
| | - Michael Emerson
- National Heart and Lung Institute, Imperial College London, London, UK
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Gillespie S, Holloway PM, Becker F, Rauzi F, Vital SA, Taylor KA, Stokes KY, Emerson M, Gavins FNE. The isothiocyanate sulforaphane modulates platelet function and protects against cerebral thrombotic dysfunction. Br J Pharmacol 2018; 175:3333-3346. [PMID: 29797311 DOI: 10.1111/bph.14368] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 04/30/2018] [Accepted: 05/04/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND AND PURPOSE Platelet activation provides a critical link between inflammation and thrombosis. Sulforaphane (SFN), a naturally occurring isothiocyanate, has been shown to display both anti-inflammatory and anti-thrombotic actions in the systemic microvasculature. As inflammation promotes thrombosis and vice versa, in this study we investigated whether SFN is able to reduce inflammatory potentiation of thrombotic events, suppress platelet activation and thrombus formation in the cerebral microvasculature. EXPERIMENTAL APPROACH Thrombosis was induced in the murine brain using the light/dye-injury model, in conjunction with LPS treatment, with and without SFN treatment. In vitro and in vivo platelet assays (aggregation, flow and other functional tests) were also employed, using both human and murine platelets. KEY RESULTS SFN was found to reduce LPS-mediated enhancement of thrombus formation in the cerebral microcirculation. In tail-bleed experiments, LPS treatment prolonged bleeding time, and SFN treatment was found to protect against this LPS-induced derangement of platelet function. SFN inhibited collagen-mediated platelet aggregation in vitro and in vivo and the associated adhesion and impaired calcium signalling. Furthermore, glycoprotein VI was shown to be involved in the protective effects observed with SFN treatment. CONCLUSIONS AND IMPLICATIONS The data presented here provide evidence for the use of SFN in preventing stroke in selected high-risk patient cohorts.
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Affiliation(s)
| | - Paul M Holloway
- Division of Brain Sciences, Imperial College London, London, UK.,Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA, USA
| | - Felix Becker
- Department of General, Visceral and Transplant Surgery, University Hospital Muenster, Muenster, Germany
| | - Francesca Rauzi
- Platelet Biology Group, National Heart and Lung Institute, Imperial College London, London, UK
| | - Shantel A Vital
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA, USA
| | - Kirk A Taylor
- Platelet Biology Group, National Heart and Lung Institute, Imperial College London, London, UK
| | - Karen Y Stokes
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA, USA
| | - Michael Emerson
- Platelet Biology Group, National Heart and Lung Institute, Imperial College London, London, UK
| | - Felicity N E Gavins
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA, USA.,Department of Neurology, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA, USA
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Rauzi F, Kirkby NS, Edin ML, Whiteford J, Zeldin DC, Mitchell JA, Warner TD. Aspirin inhibits the production of proangiogenic 15(S)-HETE by platelet cyclooxygenase-1. FASEB J 2016; 30:4256-4266. [PMID: 27633788 PMCID: PMC5102123 DOI: 10.1096/fj.201600530r] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 09/01/2016] [Indexed: 01/06/2023]
Abstract
Regular consumption of low-dose aspirin reduces the occurrence of colorectal, esophageal, stomach, and gastrointestinal cancers. The underlying mechanism is unknown but may be linked to inhibition of angiogenesis. Because the effective doses of aspirin are consistent with the inhibition of cyclooxygenase-1 in platelets, we used liquid chromatography with tandem mass spectrometry analyses and immunoassays of human platelet releasates coupled with angiogenesis assays to search for the mediators of these effects. Blood or platelet-rich plasma from healthy volunteers stimulated with platelet activators produced a broad range of eicosanoids. Notably, preincubation of platelets with aspirin, but not with a P2Y12 receptor antagonist, caused a marked reduction in the production of 11-hydroxyeicosatetraenoic acid (HETE) and 15(S)-HETE, in addition to prostanoids such as thromboxane A2. Releasates from activated platelets caused cell migration and tube formation in cultured human endothelial cells and stimulated the sprouting of rat aortic rings in culture. These proangiogenic effects were absent when platelets were treated with aspirin but returned by coincubation with exogenous 15(S)-HETE. These results reveal 15(S)-HETE as a major platelet cyclooxygenase-1 product with strong proangiogenic effects. Thus, 15(S)-HETE represents a potential target for the development of novel antiangiogenic therapeutics, and blockade of its production may provide a mechanism for the anticancer effects of aspirin.—Rauzi, F., Kirkby, N. S., Edin, M. L., Whiteford, J. Zeldin, D. C., Mitchell, J. A., Warner, T. D. Aspirin inhibits the production of proangiogenic 15(S)-HETE by platelet cyclooxygenase-1.
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Affiliation(s)
- Francesca Rauzi
- The William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Nicholas S Kirkby
- The William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.,National Heart and Lung Institute, Imperial College London, London, United Kingdom; and
| | - Matthew L Edin
- National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - James Whiteford
- The William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Darryl C Zeldin
- National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Jane A Mitchell
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; and
| | - Timothy D Warner
- The William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom;
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Kirkby NS, Reed DM, Edin ML, Rauzi F, Mataragka S, Vojnovic I, Bishop-Bailey D, Milne GL, Longhurst H, Zeldin DC, Mitchell JA, Warner TD. Inherited human group IVA cytosolic phospholipase A2 deficiency abolishes platelet, endothelial, and leucocyte eicosanoid generation. FASEB J 2015; 29:4568-78. [PMID: 26183771 PMCID: PMC4608906 DOI: 10.1096/fj.15-275065] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/06/2015] [Indexed: 12/25/2022]
Abstract
Eicosanoids are important vascular regulators, but the phospholipase A2
(PLA2) isoforms supporting their production within the cardiovascular
system are not fully understood. To address this, we have studied platelets,
endothelial cells, and leukocytes from 2 siblings with a homozygous loss-of-function
mutation in group IVA cytosolic phospholipase A2
(cPLA2α). Chromatography/mass spectrometry was used to determine
levels of a broad range of eicosanoids produced by isolated vascular cells, and in
plasma and urine. Eicosanoid release data were paired with studies of cellular
function. Absence of cPLA2α almost abolished eicosanoid synthesis
in platelets (e.g., thromboxane A2, control 20.5 ±
1.4 ng/ml vs. patient 0.1 ng/ml) and leukocytes
[e.g., prostaglandin E2 (PGE2), control
21.9 ± 7.4 ng/ml vs. patient 1.9 ng/ml], and this was
associated with impaired platelet activation and enhanced inflammatory responses.
cPLA2α-deficient endothelial cells showed reduced, but not
absent, formation of prostaglandin I2 (prostacyclin; control 956 ±
422 pg/ml vs. patient 196 pg/ml) and were primed for inflammation.
In the urine, prostaglandin metabolites were selectively influenced by
cPLA2α deficiency. For example, prostacyclin metabolites were
strongly reduced (18.4% of control) in patients lacking cPLA2α,
whereas PGE2 metabolites (77.8% of control) were similar to healthy
volunteer levels. These studies constitute a definitive account, demonstrating the
fundamental role of cPLA2α to eicosanoid formation and cellular
responses within the human circulation.—Kirkby, N. S., Reed, D. M., Edin, M.
L., Rauzi, F., Mataragka, S., Vojnovic, I., Bishop-Bailey, D., Milne, G. L.,
Longhurst, H., Zeldin, D. C., Mitchell, J. A., Warner, T. D. Inherited human group
IVA cytosolic phospholipase A2 deficiency abolishes platelet, endothelial,
and leucocyte eicosanoid generation.
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Affiliation(s)
- Nicholas S Kirkby
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Daniel M Reed
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Matthew L Edin
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Francesca Rauzi
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Stefania Mataragka
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Ivana Vojnovic
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - David Bishop-Bailey
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Ginger L Milne
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Hilary Longhurst
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Darryl C Zeldin
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Jane A Mitchell
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
| | - Timothy D Warner
- *National Heart and Lung Institute, Imperial College London, London, United Kingdom; William Harvey Research Institute, Queen Mary University of London, London, United Kingdom; National Institutes of Health, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA; Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom; Department of Pharmacology and Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA; and Immunology Department, Barts Health and the London National Health Service Trust, London, United Kingdom
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