Abstract 3917: Role of Endothelial Cell-Selective Adhesion Molecule in the Progression of Atherosclerosis

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Michihiko Inoue ◽  
Tatsuro Ishida ◽  
Tetsuya Hara ◽  
Cangara M Husni ◽  
Li Sun ◽  
...  

Backgrounds : Endothelial cell-selective adhesion molecule (ESAM) is a new member of the immunoglobulin superfamily, which is expressed in vascular endothelial cells. Although ESAM has been shown to mediate homohilic adhesion between endothelial cells, the interaction of ESAM and hematopoietic cells has not been ingestigated. Also, the role of ESAM in atherosclerosis remains unclear. In this study, we assessed the role of ESAM in monocyte/ macarophage infiltration, and examined effects of ESAM inactivation in the development atherosclerosis using a murine model of atherosclerosis. Methods and Results : ESAM−/− mice were bred with apoE−/− mice to generate the double knockout mice, and the lesion size of aortic sinus was evaluated histologically between ESAM+/+ apoE−/− and ESAM−/− apoE+/+ mice. Plasma lipid profile was not affected by ESAM deficiency. However, the lesion size was markedly attenuated in ESAM−/− apoE−/− mice compared to ESAM+/+apoE−/− mice. The percentage of MOMA-2-stained area in the aortic sinus lesions was significantly smaller in ESAM-/-apoE−/− mice than in ESAM+/+apoE−/− mice, suggesting that ESAM deficiency reduced the macrophage infiltration in the atheroma. To clarify the mechanism for the reduced macrophage content in the plaque, in vitro adhesion- and transendothelial migration assays were performed between cultured endothelial monolayers and monocyte/macrophage cell line THP-1 cells utilizing siRNA-mediated knockdown of ESAM. These assays revealed that ESAM deficiency in endothelial cells resulted in decreases in monocyte adhesion to the endothelial cells as well as transendothelialmigration. THP-1 cells did not express ESAM, but directly bound to the recommbinant ESAM protein-coated culture plates. Conclusion : ESAM modulates macrophage infiltration into the atheroma through interaction with unidentified ligand(s) on monocytes. ESAM inactivation can reduce susceptibility to atherosclerosis.

2020 ◽  
pp. jcs.248237
Author(s):  
Zhenguo Yang ◽  
Shuilong Wu ◽  
Federica Fontana ◽  
Yanyu Li ◽  
Wei Xiao ◽  
...  

Steinberg's differential adhesion hypothesis suggests that adhesive mechanisms are important for sorting of cells and tissues during morphogenesis (Steinberg, 2007). During zebrafish vasculogenesis, endothelial cells sort into arterial and venous vessel beds but it is unknown whether this involves adhesive mechanisms. Claudins are tight junction proteins regulating the permeability of epithelial and endothelial tissue barriers. Previously, the roles of Claudins during organ development have exclusively been related to their canonical functions in determining paracellular permeability. Here, we use atomic force microscopy to quantify Claudin-5-dependent adhesion and find that this strongly contributes to the adhesive forces between arterial endothelial cells. Based on genetic manipulations, we reveal a non-canonical role of Claudin-5a during zebrafish vasculogenesis, which involves the regulation of adhesive forces between adjacent dorsal aortic endothelial cells. In vitro and in vivo studies demonstrate that loss of Claudin-5 results in increased motility of dorsal aorta endothelial cells and in a failure of the dorsal aorta to lumenize. Our findings uncover a novel role of Claudin-5 in limiting arterial endothelial cell motility, which goes beyond its traditional sealing function during embryonic development.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 840-840
Author(s):  
Vesselina G. Cooke ◽  
Meghna U. Naik ◽  
William Skarnes ◽  
Ulhas P. Naik

Abstract Neovascularization is a multistep process that occurs in the body in both physiological and pathological conditions. We have recently shown that Junctional Adhesion Molecule-1 (JAM-1), a member of the Ig superfamily of molecules, is involved in endothelial cell adhesion and migration, leading to angiogenesis. In quiescent endothelial cells, JAM-1 is located at the cell-cell junctions where it forms a complex with integrin αvβ3. Upon treatment of the cells with growth factors, such as bFGF, JAM-1 dissociates from its complex with αvβ3 and redistributes to the cell surface. Blockage of the extracellular domain of JAM-1 inhibits bFGF-induced endothelial cell morphology, proliferation and angiogenesis. Additionally, functional knock-down of JAM-1 using the RNAi technique in endothelial cells showed decreased adhesion and migration of these cells, indicating a possible role for JAM-1 in angiogenesis. In this report, we show that JAM-1 has an important role in bFGF-induced angiogenesis in vivo. Here we present for the first time the generation JAM-1 knock-out mice, using the gene trap strategy. We have successfully confirmed the JAM-1 −/− genotype via Southern, Northern, and Western blot analyses. JAM-1 −/− mice are viable and do not seem to have any external abnormalities, except that they appear to be smaller in size. Retinal fluorescein angiogram revealed no evidence for morphological defects in the vasculature of JAM-1 −/− mice. To evaluate the role of JAM-1 in angiogenesis, we performed an aortic ring assay with both wild type and JAM-1−/− mice. Mouse thoracic aortas were harvested, cross-sectioned into rings of 1-mm thickness, and cultured in a three-dimensional Matrigel supplied with 50 ng/ml bFGF. Vascular sproutings were counted every other day for a period of 7 days at which time they were stained with crystal violet and photographed. Aortic rings from WT mice treated with bFGF showed a 2.8-fold increase in microvessel growth, compared to WT controls with no supplementation of bFGF. In contrast, microvessel sproutings in bFGF treated aortic rings from JAM-1 −/− mice were no more than the vessels in the WT control mice. These results suggest that JAM-1 may be important for bFGF induced angiogenesis. To further confirm the role of JAM-1 in angiogenesis, WT and JAM-1 −/− mice were injected in their flank region with Matrigel containing 80 ng/ml bFGF and 60 U/ml heparin. Two weeks after injection, Matrigel plugs were excised, embedded in paraffin, and the presence of blood vessels was visualized by H&E staining. Matrigel plugs from control WT mice that were not treated with bFGF showed no vascularization, while bFGF supplied Matrigel plugs from WT mice showed a robust vessel growth. Interestingly, bFGF-treated Matrigel plugs form JAM-1−/− mice failed to produce any blood vessels. These ex vivo and in vivo studies using JAM-1−/− mice suggest that JAM-1 has a unique and essential role in bFGF-induced angiogenesis.


Blood ◽  
2008 ◽  
Vol 111 (8) ◽  
pp. 4096-4105 ◽  
Author(s):  
Marc Tjwa ◽  
Lola Bellido-Martin ◽  
Yuan Lin ◽  
Esther Lutgens ◽  
Stéphane Plaisance ◽  
...  

AbstractThe role of Gas6 in endothelial cell (EC) function remains incompletely characterized. Here we report that Gas6 amplifies EC activation in response to inflammatory stimuli in vitro. In vivo, Gas6 promotes and accelerates the sequestration of circulating platelets and leukocytes on activated endothelium as well as the formation and endothelial sequestration of circulating platelet-leukocyte conjugates. In addition, Gas6 promotes leukocyte extravasation, inflammation, and thrombosis in mouse models of inflammation (endotoxinemia, vasculitis, heart transplantation). Thus, Gas6 amplifies EC activation, thereby playing a key role in enhancing the interactions between ECs, platelets, and leukocytes during inflammation.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
F Ravera ◽  
S Femmino' ◽  
C Penna ◽  
L Franchin ◽  
F Angelini ◽  
...  

Abstract Background Extracellular vesicles (EV) are recognized as carriers of relevant biological effects and have been identified as regulators of cell-to-cell communication contributing to several patho-physiological processes. These processes include angiogenesis/coagulation/tissue repair/inflammation. In ischemia/reperfusion (I/R) settings, along with the direct effects of the I/R itself, paracrine mechanisms associated with the activation of the inflammatory response, primary involving endothelial cells, are crucial drivers of both vessel and cardiomyocyte damage. Purpose Since in models of myocardial I/R injury the role of EV released from endothelial cells is still unclear, our hypothesis was to provide insight on this specific topic. To this end, naïve endothelial cell (EC)-derived EV (eEV) and eEV released in response to the pro-inflammatory cytokine interleukin-3 (IL-3) (eEV-IL-3) have been evaluated on different I/R models. Methods eEV were characterized by MACSPlex-Exosome-Kit and western blot analysis. For the in-vitro hypoxia-reoxygenation (H/R) experiments, H9c2 or EC were pretreated with eEV, eEV-IL-3 (1x104 EV/cell) or IL-3 (10ng/ml) for 2 hours and then exposed to hypoxia (1% O2, 5% CO2) for additional 2 hours in the presence of eEV, eEV-IL-3 or IL-3 and subsequently reoxygenated (21% O2 and 5% CO2) for 1 hour. To verify the effect of EC treated with eEV, eEV-IL-3 or IL-3 on H9c2 and subjected to H/R protocol, transwell assay was used. At the end of the H/R protocol, cell viability was assessed. For ex-vivo experiments, isolated rat hearts, pretreated with a buffer containing EV (from EC pretreated or not with IL-3), were subjected to 30 minutes global normothermic ischemia and 1 hour reperfusion. Triton infusion was also used as a model of endothelial damage. At the end of I/R, the infarct size was measured and expressed as a percentage of total left ventricular mass (LVM). The role of eNOS/guanylyl-cyclase/MEK1/2 pathways in mediating eEV biological effects was also evaluated using different inhibitors both in in-vitro and ex-vivo models. Finally, protein profiles of eEV and eEV-IL-3 were analyzed using label free mass spectrometry. Results eEV and eEV-IL-3 protect EC, but not H9c2 exposed to H/R protocol, while eEV, but not eEV-IL-3-treatment limits I/R injury in the rat heart. Rat hearts pre-treated with triton significantly avoid eEV-induced cardio-protection. Transwell assay showed a reduction of H9C2 mortality after treatment with both eEV and eEV-IL-3. Proteomic analysis revealed that MEK1/2 and the endothelial-NOS (eNOS)-antagonist caveolin-1 were differentially expressed in eEV and eEV-IL-3. The use of eNOS/guanylyl-cyclase/MEK1/2 inhibitors prevented eEV-induced cardio-protection. Conclusions These observations indicate that eEV, but not eEV-IL-3, have cardio-protective effects when given as preconditioning agents. We have also shown that the activation of eNOS/GC/MEK1/2 pathway is crucial for eEV-mediated cardio-protection. Funding Acknowledgement Type of funding source: None


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 764-764
Author(s):  
Qizhen Shi ◽  
Scot A. Fahs ◽  
Erin L. Kuether ◽  
Robert R. Montgomery

Abstract von Willebrand factor (VWF) is a carrier protein for factor VIII (FVIII) and protects plasma FVIII from protease degradation. Our laboratory has had a longstanding interest in the association of FVIII with VWF both in vitro and in vivo. Our in vitro studies have demonstrated that FVIII stores together with VWF in both endothelial cells and megakaryocytes if FVIII is made in these cells. Furthermore, we demonstrated that FVIII and VWF are both releasable by agonist stimulation. To investigate the association of VWF and FVIII in vivo, we generated two lines of transgenic mice that express FVIII either in endothelial cells or in platelets using either the endothelial cell-specific Tie2 promoter or the platelet-specific αIIb promoter, respectively. When the platelet-specific FVIII (2bF8) transgene is bred into the FVIIInull mouse, FVIII can only be detected in platelets, with a level of 0.76 ± 0.27 mU/108 platelets in heterozygous and 1.53 ± 0.14 mU/108 platelets in homozygous 2bF8 mice. When the endothelial cell-specific FVIII (Tie2F8) transgene is bred into the FVIIInull mouse, homozygous Tie2F8 mice maintained normal plasma FVIII levels (1.15 ± 0.16 U/ml) and 50% levels in heterozygous mice (0.56 ± 0.16 U/ml). Both 2bF8trans and Tie2F8trans phenotypes effectively abrogate the bleeding diathesis in hemophilic mice. When 2bF8 transgene was bred into a FVIII and VWF double knockout background, the level of platelet-FVIII significantly decreased, but this platelet-derived FVIII was still stored in a-granules and still maintained clinical efficacy. In contrast, when the Tie2F8 transgene was bred into the double knockout background, plasma FVIII dropped to undetectable levels. This is in contrast to the situation in VWFnull mice in which normal endogenous murine FVIII is synthesized with about 10% of normal FVIII activity persisting in plasma. This could be due to a difference in survival between human FVIII and murine FVIII. All Tie2F8trans/FVIIInullVWFnull mice (n=15) survived tail clipping even though there is no FVIII:C detected in the plasma. To investigate the effect of murine VWF on the levels of plasma FVIII, plasma from FVIIInull mice was infused into Tie2F8trans/FVIIInullVWFnull mice to restore VWF levels to 25% of normal. As expected, the endothelial cell-derived plasma FVIII was stabilized by the infused VWF and was detected within 1 hour after infusion, with a peak (25% level) at 4 hours. The level of plasma FVIII at 24 hours was still about 20% of normal while the level of remaining VWF was only 5% of normal. These results demonstrate that VWF is important for site-specific FVIII expression. Co-expression with VWF in platelets is important for optimal platelet-specific FVIII expression and endothelial cell-derived plasma FVIII is VWF-dependent.


1994 ◽  
Vol 3 (2) ◽  
pp. 149-153 ◽  
Author(s):  
J. M. Klausner ◽  
S. Abu-Abid ◽  
J. S. Alexander ◽  
R. Hanshke-Mineau ◽  
G. Goldman ◽  
...  

The study tests the role of thromboxane in modulating microvascular permeabilityin vitro. Cultured monolayers of bovine aortic endothelial cells were challenged with the thromboxane (Tx) mimic U46619. This led to disassembly of actin microfilaments, cell rounding, border retraction and interendotheHal gap formation. Pretreatment with the Tx receptor antagonist SQ 29,548 prevented the Tx mimic-induced cytoskeletal changes. The Tx mimic also altered endothelial cell barrier function. Increased permeability was indicated by the increased passage of labelled albumin across monolayers cultured on microcarriers, relative to untreated endothelial cells (p<0.05). Furthermore, electron microscopy of endothelial cells cultured on the basement membrane of human placental amnion indicated increased permeability based on wide, interendotheHal gap formation and transit of the tracer horseradish peroxidase. Quantification of interendothelial gaps revealed an eleven-fold increase with the Tx mimic relative to untreated endothial cells (p<0.05) and prevention by pretreatment with the Tx receptor antagonist (p<0.05). These data indicate that Tx directly modulates the permeability of endothelial cellin vitro.


2008 ◽  
Vol 76 (8) ◽  
pp. 3429-3438 ◽  
Author(s):  
Lisa Y. Chiang ◽  
Donald C. Sheppard ◽  
Fabrice N. Gravelat ◽  
Thomas F. Patterson ◽  
Scott G. Filler

ABSTRACT Invasive aspergillosis is characterized by hyphal invasion of the blood vessels, which contributes to the pathogenesis of this disease. During this angioinvasion, Aspergillus fumigatus interacts with the endothelial cell lining of the blood vessels. We investigated the response of vascular endothelial cells to A. fumigatus infection in vitro and in mouse models of invasive pulmonary aspergillosis. Infection with hyphae, but not with conidia, stimulated endothelial cells to synthesize E-selectin, vascular cell adhesion molecule 1 (VCAM-1), interleukin 8, and tumor necrosis factor alpha (TNF-α) in vitro. Killed hyphae induced approximately 40% less stimulation than did live hyphae. Endothelial cell stimulation required contact between the hyphae and endothelial cells but not endocytosis of the organisms. Studies with ΔgliP and ΔstuA null mutants of A. fumigatus indicated that the extent of endothelial cell stimulation was not influenced by gliotoxin or other StuA-dependent factors synthesized by A. fumigatus. In neutropenic mice infected with wild-type A. fumigatus, increased pulmonary expression of E-selectin, cytokine-induced neutrophil chemoattractant (KC), and TNF-α occurred only when neutropenia had resolved. In nonneutropenic mice immunosuppressed with corticosteroids, A. fumigatus stimulated earlier pulmonary expression of E-selectin, VCAM-1, and KC, while expression of intercellular adhesion molecule 1 and TNF-α was suppressed. In both mouse models, expression of E-selectin and KC was associated with high pulmonary fungal burden, angioinvasion, and neutrophil adherence to endothelial cells. Therefore, the expression of leukocyte adhesion molecules and secretion of proinflammatory cytokines by endothelial cells in response to A. fumigatus could enhance the host defense against this organism by contributing to the recruitment of activated leukocytes to sites of angioinvasion.


Sign in / Sign up

Export Citation Format

Share Document