Internalization of IgG-Coated Targets Results in Activation and Secretion of Soluble CD40 Ligand and RANTES by Human Platelets

ABSTRACTPlatelets are crucial elements for maintenance of hemostasis. Other functions attributable to platelets are now being appreciated, such as their role in inflammatory reactions and host defense. Platelets have been reported to bind immunological stimuli like IgG complexes, and for nearly 50 years it has been speculated that platelets may participate in immunological reactions. Platelets have been reported to bind and internalize various substances, similar to other leukocytes, such as macrophages and dendritic cells. In the present study, we tested the hypothesis that human platelets can bind and internalize IgG-coated particles, similar to leukocytes. To this end, we observed that interaction with IgG-coated beads resulted in platelet activation (as measured by CD62P expression), internalization of targets, and significant soluble CD40 ligand (sCD40L) and RANTES (regulated uponactivation,normalTcellexpresses andsecreted) secretion. Blocking FcγRIIA with monoclonal antibody (MAb) IV.3 or inhibiting actin remodeling with cytochalasin D inhibited platelet activation, internalization, and cytokine production. These data suggest that platelets are capable of mediating internalization of IgG-coated particles, resulting in platelet activation and release of both sCD40L and RANTES.

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Increased Concentrations of Soluble CD40 Ligand, RANTES and GRO-α in Preeclampsia – Possible Role of Platelet Activation

Thrombosis and Haemostasis ◽

10.1055/s-0037-1616061 ◽

2001 ◽

Vol 86 (11) ◽

pp. 1272-1276 ◽

Cited By ~ 21

Author(s):

Nils Olav Solum ◽

Thor Ueland ◽

Vibeke Videm ◽

Pål Aukrust ◽

Jan Roar Mellembakken

Keyword(s):

Platelet Activation ◽

Inflammatory Mediators ◽

Ex Vivo ◽

Platelet Rich Plasma ◽

Cd40 Ligand ◽

Soluble Cd40 Ligand ◽

Inflammatory Reactions ◽

Free Plasma

SummaryActivated platelets may release inflammatory mediators that activate leukocytes and trigger inflammatory reactions in endothelial cells. We examined the concentrations of soluble CD40 ligand (sCD40L) and the chemokines RANTES and GRO-α in platelet-free plasma (PFP), and unstimulated and SFLLRN-stimulated platelet-rich plasma (PRP), as well as in platelet pellets before stimulation using enzyme immunoassays. Nineteen women with normal and twenty-one with preeclamptic pregnancies were studied, and several differences between these two groups of pregnancies were revealed (1). Women with preeclampsia had significantly increased concentrations of sCD40L and GRO-α in PFP (2). Platelets from these patients spontaneously released larger quantities of CD40L and RANTES ex vivo (3). When further activated ex vivo by SFLLRN, platelets from preeclamptic women released lower amounts per platelet of CD40L, RANTES and GRO-α (4). The platelet pellets in preeclamptic women contained decreased amounts of CD40L, RANTES and GRO-α per platelet. Our findings suggest enhanced platelet activation in vivo during preeclampsia resulting in increased release of inflammatory mediators, possibly contributing to inflammation, leukocyte activation and endothelial dysfunction in this disorder.

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Relationship Between Markers of Platelet Activation and Inflammation with Disease Activity in Wegener’s Granulomatosis

The Journal of Rheumatology ◽

10.3899/jrheum.100735 ◽

2011 ◽

Vol 38 (6) ◽

pp. 1048-1054 ◽

Cited By ~ 34

Author(s):

GUNNAR TOMASSON ◽

MICHAEL LAVALLEY ◽

KAHRAMAN TANRIVERDI ◽

JAVIER D. FINKIELMAN ◽

JOHN C. DAVIS ◽

...

Keyword(s):

Disease Activity ◽

Platelet Activation ◽

Wegener’S Granulomatosis ◽

Antineutrophil Cytoplasmic Antibody ◽

Cd40 Ligand ◽

Wegener's Granulomatosis ◽

Soluble Cd40 Ligand ◽

Monocyte Chemoattractant Protein 1 ◽

Unit Increase ◽

Active Disease

Objective.There remains a need for biomarkers to guide therapy in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Our objective was to determine whether measures of platelet activation or inflammation are associated with disease activity in Wegener’s granulomatosis (WG).Methods.Study subjects were participants in a clinical trial. Soluble CD40 ligand (sCD40L), C-reactive protein, interleukin 6 (IL-6), IL-8, monocyte chemoattractant protein 1 (MCP-1), P-selectin, vascular endothelial growth factor, and proteinase 3 (PR3)-specific ANCA were measured by ELISA using plasma samples obtained at baseline (active disease), at remission, and prior to, during, and after first flares. Disease activity was assessed by the Birmingham Vasculitis Activity Score for WG (BVAS/WG). Association of biomarkers with disease activity was determined with conditional logistic and linear regression.Results.Over a mean followup of 27 months, 180 subjects underwent 2044 visits; markers were measured in 563 samples. Longitudinally, all markers other than IL-6 were associated with disease activity. The strongest associations for active disease at baseline versus remission were observed for sCD40L (OR 4.72, 95% CI 2.47–9.03), P-selectin (OR 6.26, 95% CI 2.78–14.10), PR3-ANCA (OR 9.41, 4.03–21.99), and inversely for MCP-1 (OR 0.36, 95% CI 0.22–0.57). BVAS/WG increased by 0.80 (95% CI 0.44–1.16), 0.83 (95% CI 0.42–1.25), and 0.81 (95% CI 0.48–1.15) per unit-increase in PR3-ANCA, sCD40L, and P-selectin, respectively; and decreased by 1.54 (95% CI 0.96–2.12) per unit-increase in MCP-1.Conclusion.Cytokines arising from within the circulation, including those of platelet activation, correlate with disease activity in WG.

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Antithrombin III reduces collagen-stimulated granule secretion of PDGF-AB and the release of soluble CD40 ligand from human platelets

International Journal of Molecular Medicine ◽

10.3892/ijmm_00000477 ◽

2010 ◽

Author(s):

Kozawa

Keyword(s):

Antithrombin Iii ◽

Cd40 Ligand ◽

Human Platelets ◽

Soluble Cd40 Ligand ◽

Granule Secretion

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SHARPIN at the nexus of integrin, immune, and inflammatory signaling in human platelets

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1819156116 ◽

2019 ◽

Vol 116 (11) ◽

pp. 4983-4988 ◽

Cited By ~ 11

Author(s):

Ana Kasirer-Friede ◽

Winson Tjahjono ◽

Koji Eto ◽

Sanford J. Shattil

Keyword(s):

Protein Interactions ◽

Cd40 Ligand ◽

Surface Expression ◽

Human Platelets ◽

Inflammatory Signaling ◽

Soluble Cd40 Ligand ◽

Ubiquitin Chain ◽

Fibrinogen Receptor ◽

Primary Hemostasis ◽

Induced Pluripotent

Platelets mediate primary hemostasis, and recent work has emphasized platelet participation in immunity and inflammation. The function of the platelet-specific integrin αIIbβ3 as a fibrinogen receptor in hemostasis is well defined, but the roles of αIIbβ3 or integrin-associated proteins in nonhemostatic platelet functions are poorly understood. Here we show that human platelets express the integrin-associated protein SHARPIN with functional consequences. In leukocytes, SHARPIN interacts with integrin α cytoplasmic tails, and it is also an obligate member of the linear ubiquitin chain assembly complex (LUBAC), which mediates Met1 linear ubiquitination of proteins leading to canonical NF-κB activation. SHARPIN interacted with αIIb in pull-down and coimmunoprecipitation assays. SHARPIN was partially localized, as was αIIbβ3, at platelet edges, and thrombin stimulation induced more central SHARPIN localization. SHARPIN also coimmunoprecipitated from platelets with the two other proteins comprising LUBAC, the E3 ligase HOIP and HOIL-1. Platelet stimulation with thrombin or inflammatory agonists, including lipopolysaccharide or soluble CD40 ligand (sCD40L), induced Met1 linear ubiquitination of the NF-κB pathway protein NEMO and serine-536 phosphorylation of the p65 RelA subunit of NF-κB. In human megakaryocytes and/or platelets derived from induced pluripotent stem (iPS) cells, SHARPIN knockdown caused increased basal and agonist-induced fibrinogen binding to αIIbβ3 as well as reduced Met1 ubiquitination and RelA phosphorylation. Moreover, these SHARPIN knockdown cells exhibited increased surface expression of MHC class I molecules and increased release of sCD40L. These results establish that SHARPIN functions in the human megakaryocyte/platelet lineage through protein interactions at the nexus of integrin and immune/inflammatory signaling.

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Platelet-specific markers are associated with monocyte-platelet aggregate formation and thrombin generation potential in advanced atherosclerosis

Thrombosis and Haemostasis ◽

10.1160/th15-07-0598 ◽

2016 ◽

Vol 115 (03) ◽

pp. 615-621 ◽

Cited By ~ 17

Author(s):

Cihan Ay ◽

Julia Riedl ◽

Christoph W. Kopp ◽

Beate Eichelberger ◽

Renate Koppensteiner ◽

...

Keyword(s):

Platelet Activation ◽

Thrombin Generation ◽

Thrombus Formation ◽

Cd40 Ligand ◽

Aggregate Formation ◽

Soluble Cd40 Ligand ◽

Platelet Factor ◽

Platelet Aggregate ◽

Angioplasty And Stenting

SummaryPlatelet activation and thrombin generation are crucial steps in primary and secondary haemostasis. However, both also play major roles in intravascular thrombus formation and therefore in the development of adverse cardiovascular events. In the current study, we first sought to investigate the associations of the platelet biomarkers platelet factor (PF)-4, thrombospondin (TSP)-1, soluble CD40 ligand (sCD40L), and soluble P-selectin (sP-selectin) with each other and with monocyte-platelet aggregate (MPA) formation in 316 patients undergoing angioplasty and stenting. To better understand the interplay between platelet activation and thrombin generation, we subsequently investigated the associations of the platelet biomarkers with thrombin generation potential. The mostly platelet-specific markers PF-4, TSP-1 and sCD40L correlated strongly with each other (all p < 0.001), and the best correlation was observed between PF-4 and TSP-1 (r=0.91). In contrast, sP-selectin, which derives from platelets and endothelial cells, correlated rather poorly with TSP-1 (r=0.12, p=0.04), and did not correlate with PF-4 and sCD40L. While PF-4, TSP-1 and sP-selectin correlated significantly with in vivo MPA formation (all p < 0.001), no such association was found between sCD40L and MPA formation. PF-4, TSP-1 and sCD40L correlated strongly with peak thrombin generation (all p < 0.001) with the best correlation between PF-4 and peak thrombin generation (r=0.55), whereas sP-selectin did not correlate with peak thrombin generation. Likewise, PF-4, TSP-1 and sCD40L correlated significantly with the area under the thrombin generation curve (AUC; all p< 0.01), whereas sP-selectin did not correlate with the AUC. In conclusion, platelet-specific markers are associated with MPA formation and thrombin generation potential in patients with advanced atherosclerosis.

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αB-crystallin reduces ristocetin-induced soluble CD40 ligand release in human platelets: Suppression of thromboxane A2 generation

Molecular Medicine Reports ◽

10.3892/mmr.2015.3445 ◽

2012 ◽

Vol 12 (1) ◽

pp. 357-362 ◽

Cited By ~ 1

Author(s):

MASANORI TSUJIMOTO ◽

TOMOAKI DOI ◽

GEN KUROYANAGI ◽

NAOHIRO YAMAMOTO ◽

RIE MATSUSHIMA-NISHIWAKI ◽

...

Keyword(s):

Thromboxane A2 ◽

Cd40 Ligand ◽

Human Platelets ◽

Soluble Cd40 Ligand ◽

Αb Crystallin

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High-Sensitivity C-Reactive Protein and Soluble CD40 Ligand as Indices of Inflammation and Platelet Activation in 880 Patients With Nonvalvular Atrial Fibrillation

Stroke ◽

10.1161/01.str.0000260090.90508.3e ◽

2007 ◽

Vol 38 (4) ◽

pp. 1229-1237 ◽

Cited By ~ 128

Author(s):

Gregory Y.H. Lip ◽

Jeetesh V. Patel ◽

Elizabeth Hughes ◽

Robert G. Hart

Keyword(s):

Atrial Fibrillation ◽

Platelet Activation ◽

High Sensitivity ◽

Cd40 Ligand ◽

C Reactive Protein ◽

Nonvalvular Atrial Fibrillation ◽

Soluble Cd40 Ligand ◽

Reactive Protein

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Differential Responsiveness of the Platelet Biomarkers, Systemic CD40 Ligand, CD62P, and Platelet-Derived Growth Factor-BB, to Virally-Suppressive Antiretroviral Therapy

Frontiers in Immunology ◽

10.3389/fimmu.2020.594110 ◽

2021 ◽

Vol 11 ◽

Author(s):

Helen C. Steel ◽

W. D. Francois Venter ◽

Annette J. Theron ◽

Ronald Anderson ◽

Charles Feldman ◽

...

Keyword(s):

Antiretroviral Therapy ◽

Growth Factor ◽

Platelet Activation ◽

Cd40 Ligand ◽

Platelet Derived Growth Factor ◽

Suppressive Therapy ◽

Control Group ◽

Soluble Cd40 Ligand ◽

Potential Biomarker ◽

Healthy Control

Systemic biomarkers of inflammation, including cytokines and chemokines, are potentially useful in the management of both HIV infection and non-AIDS-defining disorders. However, relatively little is known about the utility of measurement of circulating biomarkers of platelet activation as a strategy to monitor the efficacy of combination antiretroviral therapy (cART), as well as the persistence of systemic inflammation following virally-suppressive therapy in HIV-infected persons. These issues have been addressed in the current study to which a cohort consisting of 199 HIV-infected participants was recruited, 100 of whom were cART-naïve and the remainder cART-treated and virally-suppressed. Fifteen healthy control participants were included for comparison. The study focused on the effects of cART on the responsiveness of three biomarkers of platelet activation, specifically soluble CD40 ligand (sCD40L), sCD62P (P-selectin), and platelet-derived growth factor-BB (PDGF-BB), measured using multiplex suspension bead array technology. Most prominently sCD40L in particular, as well as sCD62P, were significantly elevated in the cART-naïve group relative to both the cART-treated and healthy control groups. However, levels of PDGF-BB were of comparable magnitude in both the cART-naïve and –treated groups, and significantly higher than those of the control group. Although remaining somewhat higher in the virally-suppressed group relative to healthy control participants, these findings identify sCD40L, in particular, as a potential biomarker of successful cART, while PDGF-BB may be indicative of persistent low-level antigenemia.

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Hypercoagulability in Sickle Cell Disease: New Approaches to an Old Problem

Hematology ◽

10.1182/asheducation-2007.1.91 ◽

2007 ◽

Vol 2007 (1) ◽

pp. 91-96 ◽

Cited By ~ 104

Author(s):

Kenneth I. Ataga ◽

Nigel S. Key

Keyword(s):

Sickle Cell Disease ◽

Platelet Activation ◽

Sickle Cell ◽

Antiplatelet Agents ◽

Cd40 Ligand ◽

High Plasma ◽

Biologically Active ◽

Cell Disease ◽

Soluble Cd40 Ligand ◽

Clinical Endpoints

Abstract Patients with sickle cell disease (SCD) exhibit high plasma levels of markers of thrombin generation, depletion of natural anticoagulant proteins, abnormal activation of the fibrinolytic system, and increased tissue factor expression, even in the non-crisis steady state. In addition, platelets and other cellular elements are chronically activated in the non-crisis state. Despite an abundance of evidence for coagulation and platelet activation, it remains uncertain whether these changes contribute to the pathophysiology of SCD or are, rather, simple epiphenomena. With the occurrence of macrovascular thrombotic complications in SCD, as well as the recognition that soluble CD40 ligand is biologically active in SCD, coagulation and platelet activation may indeed play a role in SCD pathophysiology. Defining a role for hypercoagulability in SCD requires further understanding of its pathogenesis. Furthermore, the conduct of well-controlled clinical trials using anticoagulants and antiplatelet agents and using a variety of clinical endpoints is warranted.

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