scholarly journals Direct Activation of Human Endothelial Cells by Plasmodium falciparum-Infected Erythrocytes

2005 ◽  
Vol 73 (6) ◽  
pp. 3271-3277 ◽  
Author(s):  
Nicola K. Viebig ◽  
Ulrich Wulbrand ◽  
Reinhold Förster ◽  
Katherine T. Andrews ◽  
Michael Lanzer ◽  
...  

ABSTRACT Cytoadherence of Plasmodium falciparum-infected erythrocytes (PRBC) to endothelial cells causes severe clinical disease, presumably as a of result perfusion failure and tissue hypoxia. Cytoadherence to endothelial cells is increased by endothelial cell activation, which is believed to occur in a paracrine fashion by mediators such as tumor necrosis factor alpha (TNF-α) released from macrophages that initially recognize PRBC. Here we provide evidence that PRBC directly stimulate human endothelial cells in the absence of macrophages, leading to increased expression of adhesion-promoting molecules, such as intercellular adhesion molecule 1. Endothelial cell stimulation by PRBC required direct physical contact for a short time (30 to 60 min) and was correlated with parasitemia. Gene expression profiling of endothelial cells stimulated by PRBC revealed increased expression levels of chemokine and adhesion molecule genes. PRBC-stimulated endothelial cells especially showed increased expression of molecules involved in parasite adhesion but failed to express molecules promoting leukocyte adhesion, such as E-selectin and vascular cell adhesion molecule 1, even after challenge with TNF-α. Collectively, our data suggest that stimulation of endothelial cells by PRBC may have two effects: prevention of parasite clearance through increased cytoadherence and attenuation of leukocyte binding to endothelial cells, thereby preventing deleterious immune reactivity.

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shu-Ling Hsieh ◽  
Jyh-Jye Wang ◽  
Kuan-Hua Su ◽  
Ying-Lan Kuo ◽  
Shuchen Hsieh ◽  
...  

Gynura bicolor (Roxb. and Willd.) DC (G. bicolor) is generally used as a dietary vegetable and traditional herb in Taiwan and the Far East. G. bicolor exerts antioxidant and anti-inflammatory effects and regulates blood lipids and cholesterol. However, the effects of G. bicolor on endothelial transmigration and atherosclerosis are not clear. The present study investigated the effects of G. bicolor on endothelial permeability and transmigration in human endothelial cells. We prepared G. bicolor ether extract (GBEE) for use as the experimental material. Under TNF-α stimulation, HL-60 cell adherence to EA.hy926 cells, the shape of EA.hy926 cells, and the expression of adhesion molecules and transmigration-related regulatory molecules were analysed after pretreatment with GBEE for 24 h. GBEE inhibited leukocyte adhesion to endothelial cells, reduced intercellular adhesion molecule-1 (ICAM-1) and platelet endothelial cell adhesion molecule-1 (PECAM-1) expressions, and decreased endothelial monolayer permeability. GBEE also reduced paracellular transmigration by reducing the levels of reactive oxygen species (ROS), Src phosphorylation, and vascular endothelial-cadherin (VE-cadherin) phosphorylation. GBEE reduced transcellular migration via inhibition of Ras homolog family member A (RhoA) and Rho-associated protein kinase (ROCK) expression and phosphorylation of the ezrin-radixin-moesin (ERM) protein. Incubation of EA.hy926 cells with GBEE for 8 h and stimulation with TNF-α for 3 h reduced the phosphorylation of the inhibitor of kappa B (IĸB) and DNA-binding activity of nuclear factor-ĸB (NF-ĸB). These results suggest that GBEE has a protective effect against endothelial dysfunction via suppression of leukocyte-endothelium adhesion and transmigration.


Blood ◽  
1994 ◽  
Vol 83 (5) ◽  
pp. 1174-1178 ◽  
Author(s):  
NW Lukacs ◽  
RM Strieter ◽  
VM Elner ◽  
HL Evanoff ◽  
M Burdick ◽  
...  

Abstract The extravasation of leukocytes from the lumen of the vessel to a site of inflammation initially requires a specific binding event followed by migration of the cells through the endothelial cell layer into the inflammatory foci. The interaction of leukocytes with the endothelium via specific receptors may provide intracellular signals that activate the cells. In the present study we have investigated the production of MIP-1 alpha, a mononuclear cell chemotactic protein, during monocyte:endothelial cell interactions. Neither unstimulated nor interferon (IFN)-stimulated human umbilical vein endothelial cells (HUVECs) produced substantial MIP-1 alpha protein. However, the addition of enriched monocyte populations with unstimulated HUVECs resulted in the production of MIP-1 alpha. Monocytes cultured with IFN- gamma-activated HUVECs showed an additional increase in MIP-1 alpha production. Immunohistochemical analysis demonstrated that the monocyte was the cellular source of MIP-1 alpha production in this coculture system. The mechanism of MIP-1 alpha expression was further assessed by determining the role of adhesion molecules in the regulation of MIP-1 alpha production during monocyte:HUVEC interactions. To attenuate the increased production of MIP-1 alpha by the monocyte:HUVEC interaction, anti-adhesion molecule monoclonal antibodies (MoAbs) were added to the cultures. Addition of anti-ICAM-1 neutralizing MoAbs significantly inhibited the production of MIP-1 alpha, whereas neutralizing anti-VCAM- 1 MoAbs failed to block MIP-1 alpha production. Furthermore, MIP-1 alpha production was induced in monocytes cultured on ICAM-1-coated plates. These results indicate an intimate relationship between leukocyte-endothelial cells, adhesion molecule, and the expression of the monocyte-derived chemokine MIP-1 alpha during cellular adhesion. This mechanism may serve an important role in cell activation and recruitment of leukocytes during the initiation of an inflammatory response.


2000 ◽  
Vol 68 (3) ◽  
pp. 1134-1141 ◽  
Author(s):  
Alison S. Orozco ◽  
Xiang Zhou ◽  
Scott G. Filler

ABSTRACT Endothelial cells can influence significantly the host inflammatory response against blood-borne microbial pathogens. Previously, we found that endothelial cells respond to in vitro infection with Candida albicans by secreting interleukin 8 (IL-8) and expressing E-selectin, intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1). We have now examined the mechanisms mediating this endothelial cell response. We determined that C. albicans stimulated endothelial cells to synthesize tumor necrosis factor alpha (TNF-α), which in turn induced these infected cells to secrete IL-8 and express E-selectin by an autocrine mechanism. Expression of VCAM-1 was mediated not only by TNF-α but also by IL-1α and IL-1β, all of which were synthesized by endothelial cells in response to C. albicans. These three cytokines remained primarily cell associated rather than being secreted. Candidal induction of ICAM-1 expression was independent of TNF-α, IL-1α, and IL-1β. These observations demonstrate that different proinflammatory endothelial cell responses to C. albicans are induced by distinct mechanisms. A clear understanding of these mechanisms is important for therapeutically modulating the endothelial cell response to C. albicans and perhaps other opportunistic pathogens that disseminate hematogenously.


Blood ◽  
2009 ◽  
Vol 113 (24) ◽  
pp. 6246-6257 ◽  
Author(s):  
Abigail Woodfin ◽  
Mathieu-Benoit Voisin ◽  
Beat A. Imhof ◽  
Elisabetta Dejana ◽  
Britta Engelhardt ◽  
...  

Abstract Leukocyte transmigration is mediated by endothelial cell (EC) junctional molecules, but the associated mechanisms remain unclear. Here we investigate how intercellular adhesion molecule-2 (ICAM-2), junctional adhesion molecule-A (JAM-A), and platelet endothelial cell adhesion molecule (PECAM-1) mediate neutrophil transmigration in a stimulus-dependent manner (eg, as induced by interleukin-1β [IL-1β] but not tumor necrosis factor-α [TNF-α]), and demonstrate their ability to act in sequence. Using a cell-transfer technique, transmigration responses of wild-type and TNF-α p55/p75 receptor-deficient leukocytes (TNFR−/−) through mouse cremasteric venules were quantified by fluorescence intravital microscopy. Whereas wild-type leukocytes showed a normal transmigration response to TNF-α in ICAM-2−/−, JAM-A−/−, and PECAM-1−/− recipient mice, TNFR−/− leukocytes exhibited a reduced transmigration response. Hence, when the ability of TNF-α to directly stimulate neutrophils is blocked, TNF-α–induced neutrophil transmigration is rendered dependent on ICAM-2, JAM-A, and PECAM-1, suggesting that the stimulus-dependent role of these molecules is governed by the target cell being activated. Furthermore, analysis of the site of arrest of neutrophils in inflamed tissues from ICAM-2−/−, JAM-A−/−, and PECAM-1−/− mice demonstrated that these molecules act sequentially to mediate transmigration. Collectively, the findings provide novel insights into the mechanisms of action of key molecules implicated in leukocyte transmigration.


Blood ◽  
1994 ◽  
Vol 83 (5) ◽  
pp. 1174-1178
Author(s):  
NW Lukacs ◽  
RM Strieter ◽  
VM Elner ◽  
HL Evanoff ◽  
M Burdick ◽  
...  

The extravasation of leukocytes from the lumen of the vessel to a site of inflammation initially requires a specific binding event followed by migration of the cells through the endothelial cell layer into the inflammatory foci. The interaction of leukocytes with the endothelium via specific receptors may provide intracellular signals that activate the cells. In the present study we have investigated the production of MIP-1 alpha, a mononuclear cell chemotactic protein, during monocyte:endothelial cell interactions. Neither unstimulated nor interferon (IFN)-stimulated human umbilical vein endothelial cells (HUVECs) produced substantial MIP-1 alpha protein. However, the addition of enriched monocyte populations with unstimulated HUVECs resulted in the production of MIP-1 alpha. Monocytes cultured with IFN- gamma-activated HUVECs showed an additional increase in MIP-1 alpha production. Immunohistochemical analysis demonstrated that the monocyte was the cellular source of MIP-1 alpha production in this coculture system. The mechanism of MIP-1 alpha expression was further assessed by determining the role of adhesion molecules in the regulation of MIP-1 alpha production during monocyte:HUVEC interactions. To attenuate the increased production of MIP-1 alpha by the monocyte:HUVEC interaction, anti-adhesion molecule monoclonal antibodies (MoAbs) were added to the cultures. Addition of anti-ICAM-1 neutralizing MoAbs significantly inhibited the production of MIP-1 alpha, whereas neutralizing anti-VCAM- 1 MoAbs failed to block MIP-1 alpha production. Furthermore, MIP-1 alpha production was induced in monocytes cultured on ICAM-1-coated plates. These results indicate an intimate relationship between leukocyte-endothelial cells, adhesion molecule, and the expression of the monocyte-derived chemokine MIP-1 alpha during cellular adhesion. This mechanism may serve an important role in cell activation and recruitment of leukocytes during the initiation of an inflammatory response.


2011 ◽  
Vol 286 (41) ◽  
pp. 35407-35417 ◽  
Author(s):  
Edith Lubos ◽  
Neil J. Kelly ◽  
Scott R. Oldebeken ◽  
Jane A. Leopold ◽  
Ying-Yi Zhang ◽  
...  

Glutathione peroxidase-1 (GPx-1) is a crucial antioxidant enzyme, the deficiency of which promotes atherogenesis. Accordingly, we examined the mechanisms by which GPx-1 deficiency enhances endothelial cell activation and inflammation. In human microvascular endothelial cells, we found that GPx-1 deficiency augments intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression by redox-dependent mechanisms that involve NFκB. Suppression of GPx-1 enhanced TNF-α-induced ROS production and ICAM-1 expression, whereas overexpression of GPx-1 attenuated these TNF-α-mediated responses. GPx-1 deficiency prolonged TNF-α-induced IκBα degradation and activation of ERK1/2 and JNK. JNK or NFκB inhibition attenuated TNF-α induction of ICAM-1 and VCAM-1 expression in GPx-1-deficient and control cells, whereas ERK1/2 inhibition attenuated only VCAM-1 expression. To analyze further signaling pathways involved in GPx-1-mediated protection from TNF-α-induced ROS, we performed microarray analysis of human microvascular endothelial cells treated with TNF-α in the presence and absence of GPx-1. Among the genes whose expression changed significantly, dual specificity phosphatase 4 (DUSP4), encoding an antagonist of MAPK signaling, was down-regulated by GPx-1 suppression. Targeted DUSP4 knockdown enhanced TNF-α-mediated ERK1/2 pathway activation and resulted in increased adhesion molecule expression, indicating that GPx-1 deficiency may augment TNF-α-mediated events, in part, by regulating DUSP4.


1996 ◽  
Vol 270 (2) ◽  
pp. C522-C529 ◽  
Author(s):  
M. G. Bouma ◽  
F. A. van den Wildenberg ◽  
W. A. Buurman

Ischemia induces excessive ATP catabolism with subsequent local release of its metabolite adenosine, an autacoid with anti-inflammatory properties. Because activation of the vascular endothelium is critical to the inflammatory host response during ischemia and reperfusion, the effects of adenosine on two major determinants of endothelial cell activation (i.e., the release of proinflammatory cytokines and the expression of adhesion molecules) were studied. Adenosine dose dependently inhibited the release of interleukin (IL)-6 and IL-8 by stimulated human umbilical vein endothelial cells (HUVEC). Expression of E-selectin and vascular cell adhesion molecule 1 (VCAM-1), but not intercellular adhesion molecule 1 (ICAM-1), by activated HUVEC was also reduced by adenosine. Inhibition of endogenous adenosine deaminase activity by erythro-9-(2-hydroxy-3-nonyl)adenine or 2'-deoxycoformycin strongly enhanced the inhibitory effects of exogenous adenosine on cytokine release and expression of E-selectin and VCAM-1. However, a clear role for specific adenosine receptors in the described inhibitory events could not be established. Together, these data imply that the vascular endothelium constitutes an important target for the anti-inflammatory actions of adenosine.


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