Abstract 48: Deletion of the Neuronal Guidance Molecule Epha2 Reduces Inflammation in Experimental Atherosclerosis

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Steven D Funk ◽  
Arif Yurdagul ◽  
Jonette Green ◽  
Patrick Albert ◽  
Marshall McInnis ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Activation ◽  
Experimental Atherosclerosis ◽  
Marker Genes ◽  
Endothelial Cell Activation ◽  
Enhanced Expression ◽  
Guidance Molecule ◽  
Neuronal Guidance ◽  
Deficient Mice

Neuronal guidance molecules are increasingly implicated in inflammatory responses. Recently, our group demonstrated enhanced expression of the neuronal guidance molecule EphA2 and its ephrinA1 ligand in mouse and human atherosclerotic plaques, and elucidated a novel proinflammatory function for EphA2 perpetuating proinflammatory gene expression during endothelial cell activation. However, a direct role for Eph/ephrins in atherosclerosis has never been demonstrated. We now show that knocking out the EphA2 gene in Western diet-fed ApoE mice blunts atherosclerotic plaque location at multiple sites. This reduction in atherosclerosis is associated with decreased monocyte infiltration and diminished expression of proinflammatory genes. EphA2 reduction may affect monocyte homing through multiple mechanisms, since reducing EphA2 expression in cytokine-activated endothelial cells does not affect endothelial adhesion molecule expression or monocyte rolling but significantly decreases firm adhesion in primary human monocytes. Like endothelial cells, plaque macrophages also express EphA2, and macrophages derived from EphA2 deficient mice show diminished expression of M1 marker genes and enhanced expression of M2 marker genes compared to their ApoE counterparts. Surprisingly, EphA2 deficient mice show significantly elevated plasma cholesterol. However, this elevation does not involve increased LDL levels but instead occurs due to elevations in plasma HDL levels. Taken together, the current data suggest EphA2 inhibition results in a multifaceted protective effect on experimental atherosclerosis characterized by reduced endothelial cell activation, monocyte recruitment, and M1/M2 polarization and enhanced circulating HDL levels.

Abstract 327: Mitochondrial Functional Variation Contributes to Endothelial Cell Activation

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
David M Krzywanski ◽  
Bing Cheng ◽  
Xinggui Shen ◽  
Christopher Kevil
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Ethnic Groups ◽  
Mitochondrial Function ◽  
Cell Activation ◽  
Oxidant Stress ◽  
Oxygen Utilization ◽  
Endothelial Cell Activation ◽  
Inflammatory Conditions ◽  
Oxidant Production

Vascular oxidant stress contributes to endothelial dysfunction and plays a critical role in early stage cardiovascular disease (CVD) development. Changes in endothelial function due to oxidant stress may contribute to CVD initiation and progression through the development of a pro-inflammatory environment. Differences in mitochondrial function may contribute to this process and provide insight into why age of onset and clinical outcomes differ amongst individuals form distinct ethnic groups; but no reports demonstrate distinct mitochondrial functional parameters between normal cells. Consequently, we hypothesized that significant variations in normal mitochondrial function and oxidant production exist between endothelial cells from donors representing different ethnic groups. Aspects of mitochondrial oxygen utilization and oxidant production were assessed under basal and inflammatory conditions in human aortic endothelial cells (HAECs) isolated from African Americans (AA) and Caucasians (CA). Bioenergetic analysis indicates that compared to CA, AA HAEC utilized significantly less oxygen for ATP production, possess a lower maximal respiratory capacity, and have reduced electron leak. Significant differences in mitochondrial membrane potential, decreased expression of endothelial nitric oxide synthase, and increased levels of superoxide were also observed and AA HAEC supporting a pro-inflammatory phenotype. As a marker of endothelial cell activation, AA HAEC expressed increased levels of intercellular cell adhesion molecule-1 under both basal and inflammatory conditions that could be partially mitigated but treatment with the mitochondrially targeted antioxidant MitoTEMPO. These data demonstrate that fundamental differences exist in mitochondrial oxygen utilization and oxidant production between CA and AA HAEC and that these changes may affect endothelial cell activation. These findings are consistent with the hypothesis that differences in “normal” mitochondrial function amongst ethnic groups could influence individual susceptibility by contributing to vascular inflammation, providing important insights into the mechanisms that contribute human CVD development.

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.

Abstract MP27: Human Hypertension And Endothelial Cell Activation Promote The Formation And Activation Of Axl + Siglec-6 + Dendritic Cells Via Endothelial Release Of Growth Arrest Specific 6

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Justin P Van Beusecum ◽  
Natalia R Barbaro ◽  
Charles D Smart ◽  
David M Patrick ◽  
Cyndya A Shibao ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Endothelial Cells ◽  
Dendritic Cells ◽  
Endothelial Cell ◽  
Cell Activation ◽  
Growth Arrest ◽  
Positive Association ◽  
Endothelial Cell Activation ◽  
Human Hypertension

We have shown that dendritic cells (DCs) from hypertensive mice convey hypertension when adoptively transferred to recipients. Recently a novel subset of DCs in humans that express Axl and Sigelc-6 + (AS DCs) have been identified which drive T cell proliferation and produce IL-1β, IL-6 and IL-23, consistent with DCs we have observed in hypertension. We hypothesized that AS cells are increased in hypertension and contribute to immune activation in this disease. We quantified circulating AS DCs by flow cytometry in normotensive (n=23) and hypertensive (n=11) subjects and found a more than 2-fold increase in circulating AS DCs in hypertensive compared to normotensive subjects (297 ± 73 vs. 108 ± 26/ml; p =0.0304). To investigate the mechanism by which AS DCs are formed in hypertension, we co-cultured human aortic endothelial cells (HAECs) undergoing either normotensive (5%) or hypertensive (10%) cyclical stretch for 48 hours with CD14 + monocytes from normotensive donors. Co-culture of monocytes with HAECs exposed to 10% stretch significantly increased AS DCs and AS DC IL-1β production when compared to 5% stretch alone as assessed by flow cytometry (21 ± 5 vs. 131 ± 32 IL-1β + AS DCs). Moreover, inhibition of Axl signaling with R248, completely abolished the production of IL-1β in AS DCs (34 ± 8 IL-1β + AS DCs). In additional experiments we found that 10% stretch caused a 50% increase in release of growth arrest 6 (GAS6), the ligand for Axl, from HAECs compared to 5% stretch. Treatment of human monocytes with GAS6 mimicked the effect of 10% stretch in promoting AS cell formation and IL-1β production. Based on the increased secretion of GAS6 from HAECs, we used a J-wire to harvest human endothelial cells from 23 additional volunteers to assess endothelial cell activation and GAS6 secretion in vivo. We found a positive association between pulse pressure and plasma GAS6 (R 2 =0.25, p =0.0079) and a striking positive association between GAS6 and ICAM-1 (R 2 =0.39, p =0.0012). These data show that secretion of GAS6 by an activated endothelial seems to promote the formation and activation of AS DCs. Thus, the interplay between endothelial-derived GAS6 and AS DCs seem to be an important mechanism in human hypertension and might be a novel therapeutic target for this disease.

160. THE ROLE OF PHAGOCYTOSIS OF APOPTOTIC SYNCYTIAL KNOTS IN THE PREVENTION OF ENDOTHELIAL CELL ACTIVATION: AN IMPORTANT ADAPTATION FOR NORMAL PREGNANCY

2010 ◽  
Vol 22 (9) ◽  
pp. 78
Author(s):  
Q. Chen ◽  
H. Jin ◽  
P. Stone ◽  
L. Chamley
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Immune Responses ◽  
Cell Activation ◽  
Normal Pregnancy ◽  
Cytochalasin D ◽  
Endothelial Cell Activation ◽  
Endothelial Cell Surface ◽  
Large Numbers

Preeclampsia is characterised by an exaggerated inflammatory response and maternal endothelial cell activation. Syncytial knots, dead multinucleated fetal cells shed from the placenta in large numbers during all pregnancies, may be phagocytosed by maternal endothelial cells. Our previous studies showed that phagocytosis of necrotic but not apoptotic syncytial knots led to endothelial cell activation. It is known that phagocytosis of apoptotic cells leads to active tolerance of immune responses and in this study we questioned whether phagocytosis of apoptotic syncytial knots leads to suppression of the endothelial cells ability to be activated. Syncytial knots were harvested from 1st trimester placental explants. Monolayers of endothelial cells were pre-treated with apoptotic syncytial knots for 24 h. After washing, the endothelial cells were treated with the endothelial cell activators LPS, PMA, IL-6, or necrotic syncytial knots for 24 h. In some experiments the inhibitor of phagocytosis, cytochalasin D, was added into the cultures along with apoptotic syncytial knots. Endothelial cell-surface ICAM-1 was measured using cell based ELISAs. Expression of ICAM-1 by endothelial cells that had phagocytosed apoptotic syncytial knots prior to treatment with LPS, PMA, IL-6, or necrotic syncytial knots was significantly (P =/<0.003) reduced, compared to control endothelial cells that had not phagocytosed apoptotic syncytial knots. Inhibiting phagocytosis of apoptotic syncytial knots with cytochalasin D abolished this protective effect. Our data suggest phagocytosis of apoptotic syncytial knots results in the suppression of the ability of endothelial cells to be activated by a number of potent chemical activators, as well as by the physiologically relevant activator, necrotic syncytial knots. This work suggests that the release of apoptotic syncytial knots from the placenta during normal pregnancy may be a mechanism by which the fetus attempts to protect the maternal vasculature against activation.

scholarly journals Endothelial Cell Activation in an Embolic Ischemia-Reperfusion Injury Microfluidic Model

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 857 ◽  
Author(s):  
Danielle Nemcovsky Amar ◽  
Mark Epshtein ◽  
Netanel Korin
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Reperfusion Injury ◽  
Cell Activation ◽  
Ischemia Reperfusion Injury ◽  
Blood Clot ◽  
Ischemia Reperfusion ◽  
Clot Lysis ◽  
Endothelial Cell Activation ◽  
Myocardial Infraction

Ischemia, lack of blood supply, is associated with a variety of life-threatening cardiovascular diseases, including acute ischemic stroke and myocardial infraction. While blood flow restoration is critical to prevent further damage, paradoxically, rapid reperfusion can increase tissue damage. A variety of animal models have been developed to investigate ischemia/reperfusion injury (IRI), however they do not fully recapitulate human physiology of IRI. Here, we present a microfluidic IRI model utilizing a vascular compartment comprising human endothelial cells, which can be obstructed via a human blood clot and then re-perfused via thrombolytic treatment. Using our model, a significant increase in the expression of the endothelial cell inflammatory surface receptors E-selectin and I-CAM1 was observed in response to embolic occlusion. Following the demonstration of clot lysis and reperfusion via treatment using a thrombolytic agent, a significant decrease in the number of adherent endothelial cells and an increase in I-CAM1 levels compared to embolic occluded models, where reperfusion was not established, was observed. Altogether, the presented model can be applied to allow better understanding of human embolic based IRI and potentially serve as a platform for the development of improved and new therapeutic approaches.

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.

scholarly journals Effects of Ebola Virus Glycoproteins on Endothelial Cell Activation and Barrier Function

2005 ◽  
Vol 79 (16) ◽  
pp. 10442-10450 ◽  
Author(s):  
Victoria M. Wahl-Jensen ◽  
Tatiana A. Afanasieva ◽  
Jochen Seebach ◽  
Ute Ströher ◽  
Heinz Feldmann ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Barrier Function ◽  
Cell Activation ◽  
Matrix Protein ◽  
Ebola Virus ◽  
Endothelial Barrier ◽  
Endothelial Barrier Function ◽  
Endothelial Cell Activation ◽  
Tnf Α

ABSTRACT Ebola virus causes severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. Vascular instability and dysregulation are disease-decisive symptoms during severe infection. While the transmembrane glycoprotein GP1,2 has been shown to cause endothelial cell destruction, the role of the soluble glycoproteins in pathogenesis is largely unknown; however, they are hypothesized to be of biological relevance in terms of target cell activation and/or increase of endothelial permeability. Here we show that virus-like particles (VLPs) consisting of the Ebola virus matrix protein VP40 and GP1,2 were able to activate endothelial cells and induce a decrease in barrier function as determined by impedance spectroscopy and hydraulic conductivity measurements. In contrast, the soluble glycoproteins sGP and Δ-peptide did not activate endothelial cells or change the endothelial barrier function. The VLP-induced decrease in barrier function was further enhanced by the cytokine tumor necrosis factor alpha (TNF-α), which is known to induce a long-lasting decrease in endothelial cell barrier function and is hypothesized to play a key role in Ebola virus pathogenesis. Surprisingly, sGP, but not Δ-peptide, induced a recovery of endothelial barrier function following treatment with TNF-α. Our results demonstrate that Ebola virus GP1,2 in its particle-associated form mediates endothelial cell activation and a decrease in endothelial cell barrier function. Furthermore, sGP, the major soluble glycoprotein of Ebola virus, seems to possess an anti-inflammatory role by protecting the endothelial cell barrier function.

Role of Connective Tissue Growth Factor In Endothelin-Mediated Endothelial Cell Activation

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2107-2107
Author(s):  
Anna J Hernandez ◽  
Sonia Henriquez ◽  
Enrique R Maldonado ◽  
Rodeler Youte ◽  
Gregory N Prado ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Growth Factors ◽  
Endothelial Cell ◽  
Growth Factor ◽  
Connective Tissue ◽  
Cell Activation ◽  
Fold Increase ◽  
Tissue Growth ◽  
Vegf Expression ◽  
Endothelial Cell Activation

Abstract Abstract 2107 Endothelial cell activation and elevated levels of circulating Endothelin-1 (ET-1) have been reported in patients with atherosclerosis and sickle cell disease (SCD). ET-1 is a well-described vasoconstrictor, mitogen and regulator of endothelial cells migration that has been shown to promote structural changes in blood vessels. ET-1 is produced in response to increases in vasoactive hormones, growth factors, hypoxia, shear stress and free radicals, events that are commonly observed in patients with SCD. Endothelial cell activation is in part characterized by increases of cytokines such as monocyte chemotactic protein-1 (MCP-1) and growth factors that are important in vascular maintenance and fibrogenesis such as connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF). CTGF and VEGF are important for blood vessel remodeling, fibrogenesis and angiogenesis. Indeed there is evidence that incubation of smooth muscle cells with ET-1 leads to increases in CTGF and VEGF levels. However, the relationship between ET-1 and CTGF in endothelial cell activation is unclear. We hypothesize that increasing ET-1 would stimulate CTGF production and endothelial cell activation. We studied the effects of ET-1 on the human endothelial cell line, EA.hy926 (EA), as well as in primary cultures of mouse aortic endothelial cells (MAEC). We performed gene expression time course experiments (0, 2, 4, 8, 16, 24 Hr) on EA cells following incubation with 100nM ET-1 using quantitative RT-PCR with Taqman chemistries and GAPDH and beta-actin as endogenous controls. We observed increases of CTGF and VEGF expression between 4 and 8 hr for CTGF (1.74 fold increase vs time 0, n=6, P<0.03) and 4 hr for VEGF (2.14 fold increase vs time 0, n=3, P<0.04). Additional experiments on EA cells showed that incubation with 100nM ET-1 for 4 hr in the presence of BQ123 and BQ788, two inhibitors of ET-1 type A and B receptors, respectively, blocked the ET-1 stimulated rises in CTGF and VEGF as well as MCP-1 expression. We then performed western blot analyses (Abcam-CTGF antibody ab6992; Abcam VEGF antibody ab1316) and showed increases in cell associated CTGF protein levels following incubation of EA cells with 100nM ET-1 for 24 hr. The ET-1 stimulated rise in CTGF levels were significantly blunted by pre-incubation of EA cells with both BQ788 and BQ123. To study whether the effects of ET-1 were unique to EA cells, we also analyzed the effects of ET-1 on early cultures of MAEC isolated from C57BLJ mice. Consistent with our observations in human endothelial cells, incubation of MAEC with 100nM ET-1 for 4 hr were associated with increases of CTGF and VEGF expression (1.86 fold vs vehicle, n=3, P<0.03; 1.73 fold vs vehicle, n=3 P<0.04 respectively). Furthermore, ET-1 stimulated rises in CTGF and VEGF expressions were likewise blocked by pre-incubation with BQ123 andBQ788. We conclude that addition of ET-1 leads to activation of endothelial cells and increases in CTGF and VEGF from human and mouse endothelial cells. Thus we suggest that therapies designed to block ET-1 receptors will reduce endothelial cell activation in part by reducing CTGF production leading to alterations in cellular and tissue architecture. This work was supported by NIH R01HL090632 to AR and R01HL096518 to JRR. Disclosures: No relevant conflicts of interest to declare.

Role of endothelial nitric oxide synthase in endothelial activation: insights from eNOS knockout endothelial cells

2004 ◽  
Vol 286 (5) ◽  
pp. C1195-C1202 ◽  
Author(s):  
Peter J. Kuhlencordt ◽  
Eva Rosel ◽  
Robert E. Gerszten ◽  
Manuel Morales-Ruiz ◽  
David Dombkowski ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Adhesion ◽  
Endothelial Cell ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Cell Activation ◽  
Cell Interactions ◽  
Wild Type ◽  
Endothelial Cell Activation ◽  
Endothelial Nitric Oxide

The objective of this study was to determine whether absence of endothelial nitric oxide synthase (eNOS) affects the expression of cell surface adhesion molecules in endothelial cells. Murine lung endothelial cells (MLECs) were prepared by immunomagnetic bead selection from wild-type and eNOS knockout mice. Wild-type cells expressed eNOS, but eNOS knockout cells did not. Expression of neuronal NOS and inducible NOS was not detectable in cells of either genotype. Upon stimulation, confluent wild-type MLECs produced significant amounts of NO compared with Nω-monomethyl-l-arginine-treated wild-type cells. eNOS knockout and wild-type cells showed no difference in the expression of E-selectin, P-selectin, intracellular adhesion molecule-1, and vascular cell adhesion molecule-1 as measured by flow cytometry on the surface of platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31)-positive cells. Both eNOS knockout and wild-type cells displayed the characteristics of resting endothelium. Adhesion studies in a parallel plate laminar flow chamber showed no difference in leukocyte-endothelial cell interactions between the two genotypes. Cytokine treatment induced endothelial cell adhesion molecule expression and increased leukocyte-endothelial cell interactions in both genotypes. We conclude that in resting murine endothelial cells, absence of endothelial production of NO by itself does not initiate endothelial cell activation or promote leukocyte-endothelial cell interactions. We propose that eNOS derived NO does not chronically suppress endothelial cell activation in an autocrine fashion but serves to counterbalance signals that mediate activation.

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