Assessment of the mechanism of juxtacrine activation and adhesion of leukocytes in liver microcirculation

1999 ◽  
Vol 276 (4) ◽  
pp. G828-G834 ◽  
Author(s):  
Juliana Carvalho-Tavares ◽  
Alison Fox-Robichaud ◽  
Paul Kubes
Keyword(s):  
Molecular Mechanisms ◽  
Platelet Activating Factor ◽  
Leukocyte Recruitment ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Liver Microcirculation ◽  
20 Nm ◽  
Deficient Mice

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.

Effects of airway distension on leukocyte recruitment in the mouse tracheal microvasculature

2007 ◽  
Vol 102 (4) ◽  
pp. 1528-1534 ◽  
Author(s):  
Elizabeth M. Wagner ◽  
John Jenkins
Keyword(s):  
Molecular Mechanisms ◽  
Leukocyte Adhesion ◽  
Respir Crit ◽  
Leukocyte Recruitment ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Rat Trachea ◽  
Deficient Mice ◽  
Normal Ventilation

We have shown previously that excessive distention of the rat trachea during mechanical ventilation results in enhanced leukocyte recruitment to the airway (Lim LH and Wagner EM. Am J Respir Crit Care Med 168:1068–1074, 2003). The objectives of this study were to develop a mouse model of positive end-expiratory pressure (PEEP)-induced leukocyte recruitment to the airway and begin to pursue molecular mechanisms that may contribute to the in vivo observation of increased leukocyte adhesion after PEEP exposure. We studied C57BL/6 wild-type mice and mice deficient in P-selectin or intercellular adhesion molecule-1 (ICAM-1) exposed to intermittent PEEP (8 cmH2O) applied five times for a 1-min duration, at 10-min intervals. After the imposed ventilatory stress, during normal ventilation (0.2 ml/breath, no PEEP), leukocyte adhesion in tracheal postcapillary venules was determined using intravital microscopy. PEEP induced a time-dependent increase in leukocyte adhesion that was significantly increased between 0 and 60 min ( P < 0.01). Furthermore, PEEP-induced leukocyte adhesion at 60 min was ablated in P-selectin- and ICAM-1-deficient mice. These findings demonstrate the essential nature of both P-selectin and ICAM-1 within airway postcapillary venular endothelium for leukocyte recruitment after airway distension.

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
Keyword(s):  
Molecular Mechanisms ◽  
Thrombus Formation ◽  
Flow Chamber ◽  
Coagulation System ◽  
Intercellular Adhesion Molecule ◽  
Platelet Glycoprotein ◽  
Intercellular Adhesion Molecule 1 ◽  
Chamber Studies

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.

P-selectin-deficient mice are protected from PAF-induced shock, intestinal injury, and lethality

1997 ◽  
Vol 273 (1) ◽  
pp. G56-G61 ◽  
Author(s):  
X. Sun ◽  
R. A. Rozenfeld ◽  
X. Qu ◽  
W. Huang ◽  
F. Gonzalez-Crussi ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Tissue Injury ◽  
Platelet Activating Factor ◽  
Intestinal Injury ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Intestinal Necrosis ◽  
Peripheral Blood Neutrophil ◽  
Deficient Mice

In a previous study, we showed that anti-CD11b or anti-CD18 antibody markedly attenuated platelet-activating factor (PAF)-induced shock and intestinal necrosis in rats, whereas anti-P-selectin anti-body was ineffective. Here we used genetically altered mice to study the mechanism of PAF in mice. We found that P-selectin-deficient mice are completely protected from the adverse effects of PAF with no mortality or intestinal injury and only mild hemoconcentration and transient hypotension. In contrast, CD18- or intercellular adhesion molecule 1 (ICAM-1)-deficient mice were not protected from PAF-induced tissue injury and death. However, when ICAM-1-, but not CD18-, deficient mice were pretreated with fucoidin, the adverse effects of PAF were markedly reduced; survival was 100%, although hypotension still developed. Neutrophil-depleted mice were protected from PAF-induced intestinal injury but still developed hypotension and hemoconcentration. PAF increases peripheral blood neutrophil counts, probably by inducing granulopoiesis, since neutrophil-depleted mice still showed granulocytosis 60 min after PAF. Thus P-selectin plays an important role in PAF-induced injury in mice, and the selectins and the integrin-ICAM-1 system work in concert to mediate the inflammatory response to PAF in vivo.

Expression and self-regulatory function of cardiac interleukin-6 during endotoxemia

2000 ◽  
Vol 279 (5) ◽  
pp. H2241-H2248 ◽  
Author(s):  
Hiroshi Saito ◽  
Cam Patterson ◽  
Zhaoyong Hu ◽  
Marschall S. Runge ◽  
Ulka Tipnis ◽  
...  
Keyword(s):  
Feedback Mechanism ◽  
Intercellular Adhesion Molecule ◽  
Regulatory Function ◽  
Heart Cells ◽  
Intercellular Adhesion Molecule 1 ◽  
Negative Feedback Mechanism ◽  
Proinflammatory Mediators ◽  
Tnf Α

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.

scholarly journals HO-1/CO Maintains Intestinal Barrier Integrity through NF-κB/MLCK Pathway in Intestinal HO-1-/- Mice

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Zhenling Zhang ◽  
Lijing Zhang ◽  
Qiuping Zhang ◽  
Bojia Liu ◽  
Fang Li ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Intestinal Barrier ◽  
Heme Oxygenase 1 ◽  
Zinc Protoporphyrin ◽  
Barrier Integrity ◽  
Tnf Α ◽  
Intestinal Barrier Integrity ◽  
Deficient Mice

Background. Intestinal barrier injury is an important contributor to many diseases. We previously found that heme oxygenase-1 (HO-1) and carbon monoxide (CO) protect the intestinal barrier. This study is aimed at elucidating the molecular mechanisms of HO-1/CO in barrier loss. Materials and Methods. We induced gut leakiness by injecting carbon tetrachloride (CCl4) to wildtype or intestinal HO-1-deficient mice. In addition, we administrated tumor necrosis factor-α (TNF-α) to cells with gain- or loss-of-HO-1 function. The effects of HO-1/CO maintaining intestinal barrier integrity were investigated in vivo and in vitro. Results. Cobalt protoporphyrin and CO-releasing molecule-2 alleviated colonic mucosal injury and TNF-α levels; upregulated tight junction (TJ) expression; and inhibited epithelial IκB-α degradation and phosphorylation, NF-κB p65 phosphorylation, long MLCK expression, and MLC-2 phosphorylation after administration of CCl4. Zinc protoporphyrin completely reversed these effects. These findings were further confirmed in vitro, using Caco-2 cells with gain- or loss-of-HO-1-function after TNF-α. Pretreated with JSH-23 (NF-κB inhibitor) or ML-7 (long MLCK inhibitor), HO-1 overexpression prevented TNF-α-induced TJ disruption, while HO-1 shRNA promoted TJ damage even in the presence of JSH-23 or ML-7, thus suggesting that HO-1 dependently protected intestinal barrier via the NF-κB p65/MLCK/p-MLC-2 pathway. Intestinal HO-1-deficient mice further demonstrated the effects of HO-1 in maintaining intestinal barrier integrity and its relative mechanisms. Alleviated hepatic fibrogenesis and serum ALT levels finally confirmed the clinical significance of HO-1/CO repairing barrier loss in liver injury. Conclusion. HO-1/CO maintains intestinal barrier integrity through the NF-κB/MLCK pathway. Therefore, the intestinal HO-1/CO-NF-κB/MLCK system is a potential therapeutic target for diseases with a leaky gut.

scholarly journals Role of poly(ADP-ribose) synthetase in pulmonary leukocyte recruitment

2003 ◽  
Vol 285 (5) ◽  
pp. L996-L1005 ◽  
Author(s):  
Rainer Kiefmann ◽  
Kai Heckel ◽  
Martina Dörger ◽  
Sonja Schenkat ◽  
Mechthild Stoeckelhuber ◽  
...  
Keyword(s):  
Adhesion Molecules ◽  
Adhesion Molecule ◽  
Intercellular Adhesion ◽  
Leukocyte Recruitment ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Edema Formation ◽  
Pulmonary Microcirculation

During systemic inflammation, recruitment and activation of leukocytes in the pulmonary microcirculation may result in a potentially life-threatening acute lung injury. We elucidated the role of the poly(ADP-ribose) synthetase (PARS), a nucleotide-polymerizing enzyme, in the regulation of leukocyte recruitment within the lung with regard to the localization in the pulmonary microcirculation and in correlation to hemodynamics in the respective vascular segments and expression of intercellular adhesion molecule 1 during endotoxemia. Inhibition of PARS by 3-aminobenzamide reduced the endotoxin-induced leukocyte recruitment within pulmonary arterioles, capillaries, and venules in rabbits as quantified by in vivo fluorescence microscopy. Microhemodynamics and thus shear rates in all pulmonary microvascular segments remained constant. Simultaneously, inhibition of PARS with 3-aminobenzamide suppressed the endotoxin-induced adhesion molecules expression as demonstrated for intercellular adhesion molecule 1 by immunohistochemistry and Western blot analysis. We confirmed this result with the use of PARS knockout mice. The inhibitory effect of 3-aminobenzamide on leukocyte recruitment was associated with a reduction of pulmonary capillary leakage and edema formation. We first provide evidence that PARS activation mediates the leukocyte sequestration in pulmonary microvessels through upregulation of adhesion molecules. As reactive oxygen species released from leukocyte are supposed to cause an upregulation of adhesion molecules we conclude that PARS inhibition contributes to termination of this vicious cycle and inhibits the inflammatory process.

IS IT POSSIBLE TO IDENTIFY HUMAN PLATELETS IN VITRO AS BEING DESENSITIZED TO PLATELET ACTIVATING FACTOR (PAF-ACETHER,PAF) IN VIVO?

1987 ◽  
Author(s):  
Cs Perger ◽  
A von Felten
Keyword(s):  
Platelet Activating Factor ◽  
Test System ◽  
Human Platelets ◽  
Vacuum Filtration ◽  
Reversible Aggregation ◽  
The Individual ◽  
20 Nm ◽  
And Control

PAF is suggested to be of pathophysiological importance in a variety of diseases. Since platelets exhibit a reduced sensitivity to PAF after a contact with this agent, this behavior may be used as indicator of PAF released into the circulation. In extrinsic asthma, platelets show a diminished reaction to PAF after exposition of the patients to the antigen compared to their own platelets before exposition (Beer and von Felten, Adv. Inflamm. Res. 10:323,1986). We were therefore looking for a test system indicating directly whether platelets had been in contact with PAF.Preparation of PAF-desensitized platelets: Citrated PRP was placed in a cuvette of an aggregometer, and PAF was added in 10 portions at intervals of 10 sec (37oc, constant stirring) to a final concentration of 10 to 100 nM, depending on the individual sensitivity of each platelet preparation. Therby, only a minimal, completely reversible aggregation was registered without any release of serotonin (ST) or 3-thromboglobulin (BTG). Control platelets were pretreated with buffer instead of PAF. Both platelets preparations were kept at 37°C for 45 min. Whereas control platelets showed a secondary aggregation to PAF (5x conc. used for desensitization), PAF-pretreated piatelets were only reversibly aggregated.Sensitivity of PAF-desensitized and control platelets to other platelet agonists: No difference in aggregation, ST-or BTG-relea-se was observed after stimulation with several concentrations of ADP, collagen and arachidonate (p>0.05,n= 41).Binding of 3H-PAF to platelets: PAF-desensitized and control platelets were separated from plasma by filtration through sepharose CL-2B (Pharmacia) in hepes-buffered Tyrode’s solution. After incubation with 3H-PAF, platelets were washed on Whatman 934-AH filters (vacuum filtration). On desensitized and control platelets, we found 175±48 (mean±sd) and 231±70 3H-PAF molecules / platelet respectively after incubation with 5 nM ^h-PAF, 399±36 and 504±66 ^H-PAF molecules / platelet after incubation with 20 nM. In spite of a statistically significant reduction of PAF-binding after desensitization (p<0.01),the variability of PAF-binding between platelets of different individuals is too high to allow a discrimination of normal from PAF-desensitized platelets.

scholarly journals Monoclonal antibody to the interferon-inducible protein Leu-13 triggers aggregation and inhibits proliferation of leukemic B cells

Blood ◽  
1990 ◽  
Vol 76 (12) ◽  
pp. 2583-2593 ◽  
Author(s):  
SS Evans ◽  
DB Lee ◽  
T Han ◽  
TB Tomasi ◽  
RL Evans
Keyword(s):  
B Cells ◽  
Dna Synthesis ◽  
Lymphocytic Leukemia ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Adhesive Properties ◽  
Prolymphocytic Leukemia ◽  
Ifn Alpha

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.

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