scholarly journals Platelet interaction with activated endothelium: mechanistic insights from microfluidics

Blood ◽  
2017 ◽  
Vol 130 (26) ◽  
pp. 2819-2828 ◽  
Author(s):  
Daniëlle M. Coenen ◽  
Tom G. Mastenbroek ◽  
Judith M. E. M. Cosemans

Abstract Traditionally, in vitro flow chamber experiments and in vivo arterial thrombosis studies have been proved to be of vital importance to elucidate the mechanisms of platelet thrombus formation after vessel wall injury. In recent years, it has become clear that platelets also act as modulators of inflammatory processes, such as atherosclerosis. A key element herein is the complex cross talk between platelets, the coagulation system, leukocytes, and the activated endothelium. This review provides insight into the platelet-endothelial interface, based on in vitro flow chamber studies and cross referenced with in vivo thrombosis studies. The main mechanisms of platelet interaction with the activated endothelium encompass (1) platelet rolling via interaction of platelet glycoprotein Ib-IX-V with endothelial-released von Willebrand factor with a supporting role for the P-selectin/P-selectin glycoprotein ligand 1 axis, followed by (2) firm platelet adhesion to the endothelium via interaction of platelet αIIbβ3 with endothelial αvβ3 and intercellular adhesion molecule 1, and (3) a stimulatory role for thrombin, the thrombospondin-1/CD36 axis and cyclooxygenase 1 in subsequent platelet activation and stable thrombus formation. In addition, the molecular mechanisms underlying the stimulatory effect of platelets on leukocyte transendothelial migration, a key mediator of atheroprogression, are discussed. Throughout the review, emphasis is placed on recommendations for setting up, reporting, interpreting, and comparing endothelial-lined flow chamber studies and suggestions for future studies.

1999 ◽  
Vol 276 (4) ◽  
pp. G828-G834 ◽  
Author(s):  
Juliana Carvalho-Tavares ◽  
Alison Fox-Robichaud ◽  
Paul Kubes

Leukotriene C4(LTC4), histamine, and other mediators can induce expression of P-selectin and platelet-activating factor (PAF) on venular endothelium to recruit leukocytes in vivo and in vitro via a juxtacrine mechanism of adhesion. The objective of this study was to assess the effect of histamine and LTC4on the leukocyte recruitment in the liver and to study the components and molecular mechanisms involved in this process. We visualized the hepatic microvasculature using intravital microscopy and we determined that LTC4(20 nM) but not histamine (0.1, 0.3, or 1 mM) induced leukocyte recruitment in the liver microcirculation. Histamine could induce leukocyte recruitment but only in the presence of an antihistaminase. The LTC4-induced leukocyte recruitment occurred primarily in sinusoids (not venules) and was not inhibitable by three different anti-P-selectin antibodies (5H1, RMP-1, and RB40). Leukocyte recruitment in P-selectin-deficient mice, intercellular adhesion molecule 1 (ICAM-1)-deficient mice, and mice treated with a PAF antagonist was of the same magnitude as in wild-type animals in response to LTC4. Although PAF alone could induce adhesion in both sinusoids and postsinusoidal venules, this chemotactic agent was not involved in LTC4-induced adhesion in the liver. Finally, an overlapping role for P-selectin and ICAM-1 was ruled out as LTC4induced leukocyte recruitment in P-selectin and ICAM-1 double-deficient mice. These data demonstrate that LTC4does not activate the known early mechanisms of leukocyte recruitment, including P-selectin, PAF, or ICAM-1 in the hepatic microvasculature.


1980 ◽  
Vol 44 (02) ◽  
pp. 081-086 ◽  
Author(s):  
C V Prowse ◽  
A E Williams

SummaryThe thrombogenic effects of selected factor IX concentrates were evaluated in two rabbit models; the Wessler stasis model and a novel non-stasis model. Concentrates active in either the NAPTT or TGt50 in vitro tests of potential thrombogenicity, or both, caused thrombus formation in the Wessler technique and activation of the coagulation system in the non-stasis model. A concentrate with low activity in both in vitro tests did not have thrombogenic effects in vivo, at the chosen dose. Results in the non-stasis model suggested that the thrombogenic effects of factor IX concentrates may occur by at least two mechanisms. A concentrate prepared from platelet-rich plasma and a pyrogenic concentrate were also tested and found to have no thrombogenic effect in vivo.These studies justify the use of the NAPTT and TGt50 in vitro tests for the screening of factor IX concentrates prior to clinical use.


2000 ◽  
Vol 279 (5) ◽  
pp. H2241-H2248 ◽  
Author(s):  
Hiroshi Saito ◽  
Cam Patterson ◽  
Zhaoyong Hu ◽  
Marschall S. Runge ◽  
Ulka Tipnis ◽  
...  

Interleukin (IL)-6 reportedly has negative inotropic and hypertrophic effects on the heart. Here, we describe endotoxin-induced IL-6 in the heart that has not previously been well characterized. An intraperitoneal injection of a bacterial lipopolysaccharide into C57BL/6 mice induced IL-6 mRNA in the heart more strongly than in any other tissue examined. Induction of mRNA for two proinflammatory cytokines, IL-1β and tumor necrosis factor (TNF)-α, occurred rapidly before the induction of IL-6 mRNA and protein. Although stimulation of isolated rat neonatal myocardial cells with IL-1β or TNF-α induced IL-6 mRNA in vitro, nonmyocardial heart cells produced higher levels of IL-6 mRNA upon stimulation with IL-1β. In situ hybridization and immunohistochemical analyses localized the IL-6 expression primarily in nonmyocardial cells in vivo. Endotoxin-induced expression of cardiac IL-1β, TNF-α, and intercellular adhesion molecule 1 was augmented in IL-6-deficient mice compared with control mice. Thus cardiac IL-6, expressed mainly by nonmyocardial cells via IL-1β action during endotoxemia, is likely to suppress expression of proinflammatory mediators and to regulate itself via a negative feedback mechanism.


Blood ◽  
1990 ◽  
Vol 76 (12) ◽  
pp. 2583-2593 ◽  
Author(s):  
SS Evans ◽  
DB Lee ◽  
T Han ◽  
TB Tomasi ◽  
RL Evans

Abstract Interferon (IFN)-alpha inhibits DNA synthesis stimulated by low molecular weight B-cell growth factor (BCGF) in hairy cells in vitro, suggesting that the therapeutic efficacy of IFN-alpha in hairy cell leukemia (HCL) involves growth inhibition of malignant B cells. Evidence that the 16-Kd cell surface protein Leu-13 mediates an antiproliferative signal in T lymphocytes and is IFN-inducible in endothelial cells prompted us to examine the expression and functional role of this molecule in leukemic B cells. Leu-13 density, determined by flow cytometry, was upregulated in vitro and in vivo by IFN-alpha on malignant B cells from patients with HCL, chronic lymphocytic leukemia, and prolymphocytic leukemia. Monoclonal anti-Leu-13 triggered homotypic aggregation of leukemic B cells via an adhesion pathway that was not inhibited by antibodies to leukocyte function associated antigen-1 (LFA- 1) or intercellular adhesion molecule-1 (ICAM-1). Moreover, anti-Leu-13 potentiated the inhibitory effects of IFN-alpha on BCGF-stimulated DNA synthesis, assessed by [3H]-thymidine and [3H]-deoxyadenosine incorporation into DNA. These results indicate that Leu-13 is part of a novel IFN-inducible signaling pathway which may modify the growth and adhesive properties of leukemic B cells under physiologic or therapeutic conditions.


Blood ◽  
2002 ◽  
Vol 99 (12) ◽  
pp. 4486-4493 ◽  
Author(s):  
Gregor Theilmeier ◽  
Carine Michiels ◽  
Erik Spaepen ◽  
Ingrid Vreys ◽  
Désiré Collen ◽  
...  

Platelets are thought to play a causal role during atherogenesis. Platelet-endothelial interactions in vivo and their molecular mechanisms under shear are, however, incompletely characterized. Here, an in vivo platelet homing assay was used in hypercholesterolemic rabbits to track platelet adhesion to plaque predilection sites. The role of platelet versus aortic endothelial cell (EC) activation was studied in an ex vivo flow chamber. Pathways of human platelet immobilization were detailed during in vitro perfusion studies. In rabbits, a 0.125% cholesterol diet induced no lesions within 3 months, but fatty streaks were found after 12 months. ECs at segmental arteries of 3- month rabbits expressed more von Willebrand factor (VWF) and recruited 5-fold more platelets than controls (P < .05, n = 5 and 4, respectively). The 3-month ostia had an increased likelihood to recruit platelets compared to control ostia (56% versus 18%, P < .0001, n = 89 and 63, respectively). Ex vivo, the adhesion of 3-month platelets to 3-month aortas was 8.4-fold increased compared to control studies (P < .01, n = 7 and 5, respectively). In vitro, endothelial VWF–platelet glycoprotein (GP) Ib and platelet P-selectin– endothelial P-selectin glycoprotein ligand 1 interactions accounted in combination for 83% of translocation and 90% of adhesion (P < .01, n = 4) of activated human platelets to activated human ECs. Platelet tethering was mainly mediated by platelet GPIbα, whereas platelet GPIIb/IIIa contributed 20% to arrest (P < .05). In conclusion, hypercholesterolemia primes platelets for recruitment via VWF, GPIbα, and P-selectin to lesion-prone sites, before lesions are detectable.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 485-485
Author(s):  
Firdos Ahmad ◽  
Lucia Stefanini ◽  
Timothy Daniel Ouellette ◽  
Teshell K Greene ◽  
Stefan Feske ◽  
...  

Abstract Abstract 485 Platelet activation is a central event in thrombosis and hemostasis. We recently demonstrated that most aspects of platelet activation depend on synergistic signaling by two signaling modules: 1) Ca2+/CalDAG-GEFI/Rap1 and 2) PKC/P2Y12/Rap1. The intracellular Ca2+ concentration of platelets is regulated by Ca2+ release from the endoplasmic reticulum (ER) and store-operated calcium entry (SOCE) through the plasma membrane. Stromal interaction molecule 1 (STIM1) was recently identified as the ER Ca2+ sensor that couples Ca2+ store release to SOCE. In this study, we compared the activation response of platelets lacking STIM1−/− or CalDAG-GEFI−/−, both in vitro and in vivo. To specifically investigate Ca2+-dependent platelet activation, some of the experiments were performed in the presence of inhibitors to P2Y12. The murine Stim1 gene was deleted in the megakaryocyte/platelet lineage by breeding Stim flox/flox mice with PF4-Cre mice (STIM1fl/fl). STIM1fl/fl platelets showed markedly reduced SOCE in response to agonist stimulation. aIIbβ3 activation in STIM1fl/fl platelets was significantly reduced in the presence but not in the absence of the P2Y12 inhibitor, 2-MesAMP. In contrast, aIIbb3 activation was completely inhibited in 2-MesAMP-treated CalDAG-GEFI−/− platelets. Deficiency in STIM1, and to a lesser extent in CalDAG-GEFI, reduced phosphatidyl serine (PS) exposure in platelets stimulated under static conditions. PS exposure was completely abolished in both STIM1fl/fl and CalDAG-GEFI−/− platelets stimulated in the presence of 2-MesAMP. To test the ability of platelets to form thrombi under conditions of arterial shear stress, we performed flow chamber experiments with anticoagulated blood perfused over a collagen surface. Thrombus formation was abolished in CalDAG-GEFI−/− blood and WT blood treated with 2-MesAMP. In contrast, STIM1fl/fl platelets were indistinguishable from WT platelets in their ability to form thrombi. STIM1fl/fl platelets, however, were impaired in their ability to express PS when adhering to collagen under flow. Consistently, when subjected to a laser injury thrombosis model, STIM1fl/fl mice showed delayed and reduced fibrin generation, resulting in the formation of unstable thrombi. In conclusion, our studies indicate a critical role of STIM1 in SOCE and platelet procoagulant activity, but not in CalDAG-GEFI mediated activation of aIIbb3 integrin. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
1998 ◽  
Vol 91 (12) ◽  
pp. 4803-4809 ◽  
Author(s):  
May Ho ◽  
Tineke Schollaardt ◽  
Xiaofei Niu ◽  
Sornchai Looareesuwan ◽  
Kamala D. Patel ◽  
...  

Abstract Plasmodium falciparum-infected erythrocytes (IRBC) roll on the adhesion molecule P-selectin in vitro under flow conditions that approximate the shear stress in capillary and postcapillary venules in which cytoadherence occurs in vivo. The pathological significance of this adhesive interaction is currently unknown. In this study, we further investigated the molecular interactions between IRBC and P-selectin by using a laminar flow system that allowed for the direct visualization of IRBC-substratum interactions. The results showed that the IRBC–P-selectin interaction was Ca2+-dependent and involved the lectin domain of P-selectin and a sialic acid residue on IRBC. The sialylated P-selectin ligand was trypsin-sensitive, which suggests that it could be part of the parasite antigen PfEMP1 that interacts with CD36 and intercellular adhesion molecule-1 (ICAM-1), but different from a trypsin-resistant IRBC ligand that adheres selectively to chondroitin sulfate A. Studies on the rolling and adhesion of IRBC on activated platelets that express both CD36 and P-selectin showed that inhibition of rolling on P-selectin reduced the adhesion of some clinical parasite isolates to CD36, whereas other parasite isolates appeared to interact directly with CD36. Thus, cytoadherence under physiological flow conditions may be mediated by multiple IRBC ligands that interact with different adhesion molecules in a cooperative fashion. These findings underscore the complexity of the interactions betweeen IRBC and vascular endothelium.


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