scholarly journals Brucella abortus-Stimulated Platelets Activate Brain Microvascular Endothelial Cells Increasing Cell Transmigration through the Erk1/2 Pathway

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 708
Author(s):  
Ana María Rodríguez ◽  
Aldana Trotta ◽  
Agustina P. Melnyczajko ◽  
M. Cruz Miraglia ◽  
Kwang Sik Kim ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Brucella Abortus ◽  
Cell Activation ◽  
Transendothelial Migration ◽  
Endothelial Activation ◽  
Microvascular Endothelial Cell ◽  
Inflammatory Disorder ◽  
Endothelial Cell Activation ◽  
Microvascular Endothelial

Central nervous system invasion by bacteria of the genus Brucella results in an inflammatory disorder called neurobrucellosis. A common feature associated with this pathology is blood–brain barrier (BBB) activation. However, the underlying mechanisms involved with such BBB activation remain unknown. The aim of this work was to investigate the role of Brucella abortus-stimulated platelets on human brain microvascular endothelial cell (HBMEC) activation. Platelets enhanced HBMEC activation in response to B. abortus infection. Furthermore, supernatants from B. abortus-stimulated platelets also activated brain endothelial cells, inducing increased secretion of IL-6, IL-8, CCL-2 as well as ICAM-1 and CD40 upregulation on HBMEC compared with supernatants from unstimulated platelets. Outer membrane protein 19, a B. abortus lipoprotein, recapitulated B. abortus-mediated activation of HBMECs by platelets. In addition, supernatants from B. abortus-activated platelets promoted transendothelial migration of neutrophils and monocytes. Finally, using a pharmacological inhibitor, we demonstrated that the Erk1/2 pathway is involved in the endothelial activation induced by B. abortus-stimulated platelets and also in transendothelial migration of neutrophils. These results describe a mechanism whereby B. abortus-stimulated platelets induce endothelial cell activation, promoting neutrophils and monocytes to traverse the BBB probably contributing to the inflammatory pathology of neurobrucellosis.

Abstract 66: The Role of the Viral Nef Protein as a Mediator of HIV-1--Induced Endothelial Dysfunction

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Ting Wang
Keyword(s):  
Cardiovascular Disease ◽  
T Cells ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Endothelial Dysfunction ◽  
Binding Site ◽  
Cell Activation ◽  
Endothelial Activation ◽  
Endothelial Cell Activation ◽  
Hiv 1

With the prevalence of antiviral therapy in the developed world, many HIV-1-infected people die of diseases other than AIDS. One of the emerging major causes is cardiovascular disease, leading to the prediction that the majority of HIV-1 patients are expected to develop cardiovascular complications. Endothelial dysfunction is thought to be a key event in the development of cardiovascular diseases, particularly atherosclerosis. Assays testing the effect of HIV-1 on endothelial activation shows that direct contact with HIV-1 infected T cells enhance endothelial cell activation to a greater extent than HIV-1 alone, suggesting an intracellular HIV-1 protein is responsible for endothelial activation. The HIV-1 viral protein Nef, which is responsible for T cell activation and maintenance of high viral loads in vivo , has been shown to mediate its own transfer to bystander cells. We demonstrate here for the first time that Nef induces nanotube-like conduits connecting T cells and endothelial cells. We also show that Nef is transferred from T cells to endothelial cells via these nanotubes, and is necessary and sufficient for endothelial cell activation. Moreover, we show that SIV-infected macaques exhibit endothelial Nef expression in coronary arteries. Nef expression in endothelial cells causes endothelial apoptosis, ROS and MCP-1 production. Interestingly, a Nef SH3 binding site mutant abolishes Nef-induced apoptosis and ROS formation and reduces MCP-1 production in endothelial cells, suggesting that the Nef SH3 binding site is critical for Nef effects on endothelial cells. Nef induces apoptosis of endothelial cells through an NADPH oxidase- and ROS-dependent mechanism, while Nef-induced MCP-1 production is NF-kB dependent. Taken together, these data suggest that Nef can mediate its transfer from T cells to endothelial cells through nanotubes to enhance endothelial dysfunction.Thus, Nef is a promising new therapeutic target for reducing the risk for cardiovascular disease in the HIV-1 positive population.

scholarly journals A novel flow cytometry-based quantitative monocyte adhesion assay to estimate endothelial cell activation in vitro

BioTechniques ◽  
2020 ◽  
Vol 68 (6) ◽  
pp. 325-333
Author(s):  
Vinnyfred Vincent ◽  
Himani Thakkar ◽  
Anjali Verma ◽  
Atanu Sen ◽  
Nikhil Chandran ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Activation ◽  
Endothelial Activation ◽  
Adhesion Assay ◽  
Monocyte Adhesion ◽  
Endothelial Cell Activation ◽  
Functional Level

One of the earliest events in the development of atherosclerosis is endothelial activation, which is estimated in vitro at the functional level by quantifying monocyte adhesion. This involves the incubation of fluorescently labeled monocytes on top of cultured endothelial cells and quantifying the number of adhered monocytes. Currently, the quantification of adhered monocytes is done using microscopy or by lysing the cells and estimating the fluorescence. Here we present a novel flow cytometry-based method for the quantification of monocyte adhesion. This method could quantify the average number of monocytes adhered to a single endothelial cell after monocyte adhesion assay, and was also sensitive to the level of activation of endothelial cells. Flow cytometry-based quantification requires less time and effort compared with microscopy-based quantification.

106. IL-6 INCREASES THE SHEDDING OF NECROTIC TROPHOBLASTS FROM PLACENTAL EXPLANTS

2009 ◽  
Vol 21 (9) ◽  
pp. 25
Author(s):  
Q. Chen ◽  
L. Chen ◽  
B. Liu ◽  
H. Zhao ◽  
P. R. Stone ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Activation ◽  
Elevated Serum ◽  
Serum Levels ◽  
Endothelial Activation ◽  
Maternal Blood ◽  
Endothelial Cell Activation ◽  
Cell Monolayers ◽  
Cell Dysfunction

Preeclampsia (PE) is characterised by elevated maternal blood pressure, preceded by endothelial cell dysfunction. Dead trophoblasts, shed from the placenta may be one of the factors that trigger PE. Women with PE frequently have elevated serum levels of inflammatory markers such as, IL-6 and TNF a but their functional significance is unclear. In this study we investigated whether these or other cytokines can alter trophoblast shedding from placental explants. Placental explants were treated with 9 different cytokines for 72 hours. Shed trophoblasts then were harvested using our published method1. The numbers of trophoblasts shed were quantified by automated cell counter. Expression of active of caspases 3&7 by the shed trophoblasts was determined using a FLICA kit. The trophoblasts shed from cytokine-treated or control explants were exposed to endothelial cell monolayers and endothelial activation determined by ELISA for cell surface ICAM-1. Treatment of explants with IL-6 caused a 50% increase (p=0.001), while TNF a and TGF b 1, caused smaller significant increases in the numbers of trophoblasts shed. Trophoblasts shed from explants treated with IL-6, TGF b 1, or TGF b 3 expressed significantly less active caspases 3&7 than controls or trophoblasts shed from explants treated with other cytokines. Exposing trophoblasts shed from IL-6- or TGF b 1-treated explants to endothelial cells caused a significant (P<0.001) increase in endothelial activation. Normally trophoblasts shed from the placenta die by an apoptosis-like process and their phagocytosis by endothelial cells is silent but a shift to shedding of necrotic trophoblasts can lead to endothelial cell activation 2. However, it remains unclear what might trigger a shift from apoptotic to necrotic trophoblast death. This study suggests that IL-6 and possibly other cytokines can alter both the number and the nature of shed trophoblasts such that the trophoblast are more necrotic and their phagocytosis by maternal endothelial cells could contribute to the pathogenesis of preeclampsia.

Adiponectin Diminishes Organ-Specific Microvascular Endothelial Cell Activation Associated With Sepsis

Shock ◽  
2012 ◽  
Vol 37 (4) ◽  
pp. 392-398 ◽  
Author(s):  
Matijs van Meurs ◽  
Pedro Castro ◽  
Nathan I. Shapiro ◽  
Shulin Lu ◽  
Midori Yano ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Activation ◽  
Microvascular Endothelial Cell ◽  
Endothelial Cell Activation ◽  
Organ Specific ◽  
Microvascular Endothelial

scholarly journals Endothelial Activation in Orientia tsutsugamushi Infection Is Mediated by Cytokine Secretion From Infected Monocytes

2021 ◽  
Vol 11 ◽  
Author(s):  
Wiwit Tantibhedhyangkul ◽  
Sutthicha Matamnan ◽  
Asma Longkunan ◽  
Chawikan Boonwong ◽  
Ladawan Khowawisetsut
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Activation ◽  
Endothelial Activation ◽  
Cytokine Secretion ◽  
Cell Surface Expression ◽  
Orientia Tsutsugamushi ◽  
Endothelial Cell Activation ◽  
Chemokine Production ◽  
Delay In Diagnosis

Scrub typhus, caused by Orientia tsutsugamushi, is a common systemic infection in Asia. Delay in diagnosis and treatment can lead to vasculitis in the visceral organs and other complications. The mechanisms that drive endothelial activation and the inflammatory response in O. tsutsugamushi infection remain unknown. In addition, the interaction between monocytes and endothelial cells is still unclear. Here we demonstrate that O. tsutsugamushi-infected human dermal microvascular endothelial cells produced moderate levels of chemokines and low levels of IL-6 and IFN-β, but not TNF or IL-1β. Recombinant TNF and cytokine-rich supernatants from infected monocytes markedly enhanced chemokine production in infected endothelial cells. We also show that TNF and monocyte supernatants, but not O. tsutsugamushi infection of endothelial cells per se, upregulated the endothelial cell surface expression of ICAM-1, E-selectin, and tissue factor. This finding was consistent with the inability of O. tsutsugamushi to induce cytokine secretion from endothelial cells. The upregulation of surface molecules after stimulation with monocyte supernatants was significantly reduced by neutralizing anti-TNF antibodies. These results suggest that endothelial cell activation and response are mainly mediated by inflammatory cytokines secreted from monocytes.

scholarly journals Glutathione Peroxidase-1 Deficiency Augments Proinflammatory Cytokine-induced Redox Signaling and Human Endothelial Cell Activation

2011 ◽  
Vol 286 (41) ◽  
pp. 35407-35417 ◽  
Author(s):  
Edith Lubos ◽  
Neil J. Kelly ◽  
Scott R. Oldebeken ◽  
Jane A. Leopold ◽  
Ying-Yi Zhang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Glutathione Peroxidase ◽  
Adhesion Molecule ◽  
Cell Activation ◽  
Microvascular Endothelial Cells ◽  
Endothelial Cell Activation ◽  
Glutathione Peroxidase 1 ◽  
Tnf Α ◽  
Microvascular Endothelial

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.

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