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Jimmy Stalin,
Karim Harhouri,
Lucas Hubert,
Caroline Subrini,
Daniel Lafitte,
Jean-Claude Lissitzky,
Nadia Elganfoud,
Stephane Robert,
Alexandrine Foucault-Bertaud,
Elise Kaspi, Florence Sabatier,
Michel Aurrand-Lions,
Nathalie Bardin,
Lars Holmgren,
Francoise Dignat-George,
Marcel Blot-Chabaud
[show abstract]
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ABSTRACT: The Melanoma Cell Adhesion Molecule (MCAM/CD146) contains a circulating proteolytic variant (sCD146) which is involved in inflammation and angiogenesis. Its circulating level is modulated in different pathologies but its intracellular transduction pathways are still largely unknown. Using peptide pull-down and mass spectrometry, we identified angiomotin as a sCD146-associated protein in endothelial progenitor cells (EPC). Interaction between angiomotin and sCD146 was confirmed by enzyme-linked immunosorbent assay (ELISA), homogeneous time-resolved fluorescence (HTRF) and binding of sCD146 on both immobilized recombinant angiomotin and angiomotin-transfected cells. Silencing angiomotin in EPC inhibited sCD146 angiogenic effects, i.e. EPC migration, proliferation and capacity to form capillary-like structures in matrigel. In addition, sCD146 effects were inhibited by the angiomotin inhibitor angiostatin and competition with recombinant angiomotin. Finally, binding of sCD146 on angiomotin triggered the activation of several transduction pathways that were identified by antibody array. These results delineate a novel signaling pathway where sCD146 binds to angiomotin to stimulate a pro-angiogenic response. This result is important to find novel target cells of sCD146 and for the development of therapeutic strategies based on EPC in the treatment of ischemic diseases.
Journal of Biological Chemistry 02/2013; · 4.77 Impact Factor
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Jimmy Stalin,
Karim Harhouri,
Lucas Hubert,
Caroline Subrini,
Daniel Lafitte,
Jean-Claude Lissitzky,
Nadia Elganfoud,
Stéphane Robert,
Alexandrine Foucault-Bertaud,
Elise Kaspi, Florence Sabatier,
Michel Aurrand-Lions,
Nathalie Bardin,
Lars Holmgren,
Françoise Dignat-George,
Marcel Blot-Chabaud
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Romaric Lacroix,
Laurent Plawinski,
Stephane Robert,
Loic Doeuvre, Florence Sabatier,
Sara Martinez de Lizarrondo,
Anna Mezzapesa,
Francine Anfosso,
Aurelie Leroyer,
Pascale Poullin,
Noemi Jourde,
Makon-Sebastien Njock,
Chantal Boulanger,
Eduardo Angles-Cano,
Francoise Dignat-George
[show abstract]
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ABSTRACT: Background. We recently assigned a new fibrinolytic function to cell-derived microparticles in vitro. The relevance of this novel property of microparticles to the in vivo situation was explored in these studies.Design and Methods. Circulating microparticles were isolated from plasma of thrombotic thrombocytopenic purpura, systemic lupus erythematosus or cardiovascular disease patients and from healthy subjects. Microparticles were also obtained from purified human blood cell subpopulations. Identification of plasminogen activators on microparticles was performed by flow cytometry and ELISA, their capacity to generate plasmin quantified with a chromogenic assay and their fibrinolytic activity by zymography.Results. Circulating microparticles isolated from patients generate a range of plasmin activity at their surface. This property was related to a variable content in uPA and/or tPA. Using distinct microparticle subpopulations, we demonstrate that plasmin is generated on endothelial and leukocyte microparticles, but is absent on microparticles from platelet or erythrocyte origin. Leukocyte-derived microparticles bear uPA and its receptor uPAR whereas endothelial microparticles carry tPA and tPA/inhibitor complexes. Conclusions. Endothelial and leukocyte microparticles, bearing respectively tPA or uPA, support a part of the fibrinolytic activity in the circulation that is modulated in pathological settings. This blood-borne fibrinolytic activity conveyed by microparticles provides a more comprehensive view on the role of microparticles in the hemostatic equilibrium.
Haematologica 06/2012; · 6.42 Impact Factor
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Archives of cardiovascular diseases 12/2011; 104(12):601-3. · 0.66 Impact Factor
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Isabelle Ligi,
Stéphanie Simoncini,
Edwige Tellier,
Paula Frizera Vassallo, Florence Sabatier,
Benjamin Guillet,
Edouard Lamy,
Gabrielle Sarlon,
Cathy Quemener,
Andreas Bikfalvi,
Maxime Marcelli,
Alain Pascal,
Blandine Dizier,
Umberto Simeoni,
Françoise Dignat-George,
Francine Anfosso
[show abstract]
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ABSTRACT: Low birth weight (LBW) is associated with increased risk of cardiovascular diseases at adulthood. Nevertheless, the impact of LBW on the endothelium is not clearly established. We investigate whether LBW alters the angiogenic properties of cord blood endothelial colony forming cells (LBW-ECFCs) in 25 preterm neonates compared with 25 term neonates (CT-ECFCs). We observed that LBW decreased the number of colonies formed by ECFCs and delayed the time of appearance of their clonal progeny. LBW dramatically reduced LBW-ECFC capacity to form sprouts and tubes, to migrate and to proliferate in vitro. The angiogenic defect of LBW-ECFCs was confirmed in vivo by their inability to form robust capillary networks in Matrigel plugs injected in nu/nu mice. Gene profile analysis of LBW-ECFCs demonstrated an increased expression of antiangiogenic genes. Among them, thrombospondin 1 (THBS1) was highly expressed at RNA and protein levels in LBW-ECFCs. Silencing THBS1 restored the angiogenic properties of LBW-ECFCs by increasing AKT phosphorylation. The imbalance toward an angiostatic state provide a mechanistic link between LBW and the impaired angiogenic properties of ECFCs and allows the identification of THBS1 as a novel player in LBW-ECFC defect, opening new perspectives for novel deprogramming agents.
Blood 06/2011; 118(6):1699-709. · 9.90 Impact Factor
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Chahrazad Moubarik,
Benjamin Guillet,
Bennis Youssef,
Jean-Laurent Codaccioni,
Marie-Dominique Piercecchi, Florence Sabatier,
Pellegrini Lionel,
Laetitia Dou,
Alexandrine Foucault-Bertaud,
Lionel Velly,
Françoise Dignat-George,
Pascale Pisano
[show abstract]
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ABSTRACT: Endothelial progenitor cells (EPCs) seem to be a promising option to treat patients with ischemic diseases. Here, we investigated the effects of late outgrowth EPCs, or endothelial colony-forming cells (ECFCs), a recently defined homogeneous subtype of EPCs, in a rat model of transient middle cerebral artery occlusion (MCAO). Either vehicle or 4.10(6) ECFCs, isolated from human cord blood, were intravenously injected 24 h after 1 h MCAO in rats assigned to control and transplanted groups respectively. (111)In-oxine-labeled ECFCs specifically homed to ischemic hemisphere and CM-Dil prelabeled ECFCs preferentially settled in the inner boundary of the core area of transplanted animals. Although incorporation of cells into neovessels was hardly detectable, ECFCs transplantation was associated with a reduction in apoptotic cell number, an increase in capillary density and a stimulation of neurogenesis at the site of injury. These effects were associated with an increase in growth factors expression in homogenates from ischemic area and may be related to the secretion by ECFCs of soluble factors that could affect apoptosis, vascular growth and neurogenesis. Microscopic examination of the ischemic hemisphere showed that ECFCs transplantation was also associated with a reduction in reactive astrogliosis. In conclusion, we demonstrated that ECFCs injected 24 h after MCAO settled in the injured area and improved functional recovery. The neurological benefits may be linked to a reduction in ischemia-induced apoptosis and a stimulation of ischemia-induced angiogenesis and neurogenesis. These findings raise perspectives for the use of ECFCs as a well-characterized cell therapy product for optimal therapeutic outcome after stroke.
Stem cell reviews 03/2011; 7(1):208-20. · 5.08 Impact Factor
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Dilyana Todorova, Florence Sabatier,
Evelyne Doria,
Luc Lyonnet,
Henri Vacher Coponat,
Stéphane Robert,
Nicolas Despoix,
Tristan Legris,
Valérie Moal,
Anderson Loundou,
Sophie Morange,
Yvon Berland,
Francoise Dignat George,
Stéphane Burtey,
Pascale Paul
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ABSTRACT: Circulating CD34(+) cells, a population that includes endothelial progenitors, participate in the maintenance of endothelial integrity. Better understanding of the mechanisms that regulate their survival is crucial to improve their regenerative activity in cardiovascular and renal diseases. Chemokine-receptor cross talk is critical in regulating cell homeostasis. We hypothesized that cell surface expression of the chemokine fractalkine (FKN) could target progenitor cell injury by Natural Killer (NK) cells, thereby limiting their availability for vascular repair.
We show that CD34(+)-derived Endothelial Colony Forming Cells (ECFC) can express FKN in response to TNF-α and IFN-γ inflammatory cytokines and that FKN expression by ECFC stimulates NK cell adhesion, NK cell-mediated ECFC lysis and microparticles release in vitro. The specific involvement of membrane FKN in these processes was demonstrated using FKN-transfected ECFC and anti-FKN blocking antibody. FKN expression was also evidenced on circulating CD34(+) progenitor cells and was detected at higher frequency in kidney transplant recipients, when compared to healthy controls. The proportion of CD34(+) cells expressing FKN was identified as an independent variable inversely correlated to CD34(+) progenitor cell count. We further showed that treatment of CD34(+) circulating cells isolated from adult blood donors with transplant serum or TNF-α/IFN-γ can induce FKN expression.
Our data highlights a novel mechanism by which FKN expression on CD34(+) progenitor cells may target their NK cell mediated killing and participate to their immune depletion in transplant recipients. Considering the numerous diseased contexts shown to promote FKN expression, our data identify FKN as a hallmark of altered progenitor cell homeostasis with potential implications in better evaluation of vascular repair in patients.
PLoS ONE 01/2011; 6(10):e26663. · 4.09 Impact Factor
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Laurent Bonello,
Karim Harhouri, Florence Sabatier,
Laurence Camoin-Jau,
Laurent Arnaud,
Karine Baumstarck-Barrau,
Omar Ait-Mokhtar,
François Roubille,
Christophe Piot,
Nathalie Lesavre,
Franck Paganelli,
Françoise Dignat-George
[show abstract]
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ABSTRACT: We aimed to investigate whether clopidogrel-induced inhibition of platelet reactivity could reduce the level of circulating endothelial cells (CEC), reflecting the endothelial injury induced by percutaneous coronary intervention (PCI).
Clopidogrel loading dose before percutaneous coronary angioplasty (PCI) reduces platelet activation through a selective and irreversible blockade of the adenosine diphosphate (ADP) receptor P2Y(12). The impact of clopidogrel on endothelial cells has been scarcely studied.
A total of 149 patients undergoing PCI for stable angina were enrolled. Levels of CEC were measured at baseline (H0) and 6 (H6) and 24 (H24) h after the procedure using a CD146-based immunomagnetic separation assay. The CEC delta-change (CEC at H6 - CEC at H0) was analyzed according to ADP receptor P2Y(12) blockade, assessed by a vasodilator-stimulated phosphoprotein (VASP) assay after a 600-mg loading dose of clopidogrel.
The PCI induced a significant rise in CEC levels 6 h after the procedure. The CEC peak value was significantly higher in patients with high on-treatment platelet reactivity (VASP index ≥50%: 59.6 ± 27.5 cells/ml) as compared with good responders (VASP index <50%: 27 ± 22 cells/ml; p = 0.04). The endothelial injury, assessed by CEC delta-change between H6 and H0, was significantly higher in the high on-treatment platelet reactivity group compared with the good responders group (52.6 ± 25.6 vs. 18.6 ± 23.5, respectively; p < 0.001) and correlated with the VASP index (r = 0.59; p < 0.001). In multivariate analysis, VASP group, the number of diseased vessels, and the number of implanted stents independently predicted the endothelial injury (p < 0.001).
Optimal ADP receptor P2Y(12) blockade reduces the endothelial injury during PCI. This protective effect of clopidogrel on endothelial cells could add to the clinical benefit associated with this drug.
Journal of the American College of Cardiology 09/2010; 56(13):1024-31. · 14.16 Impact Factor
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Aurélie S Leroyer,
Francine Anfosso,
Romaric Lacroix, Florence Sabatier,
Stéphanie Simoncini,
Sébastien M Njock,
Noémie Jourde,
Philippe Brunet,
Laurence Camoin-Jau,
José Sampol,
Françoise Dignat-George
[show abstract]
[hide abstract]
ABSTRACT: Endothelial microparticles (EMP) are complex vesicular structures that can be shed by activated or apoptotic endothelial cells. EMP are composed of a phospholipid bilayer that exposes transmembrane proteins and receptors and encloses cytosolic components such as enzymes, transcription factors and mRNA derived from their parent cells. Thus, EMP behave as biological conveyors playing a key role in the tuning of vascular homeostasis. This review focuses on the multifaceted roles of EMP, notably in coagulation, inflammation and angiogenesis and also on the mechanisms that trigger their formation. In this context, EMP could compromise vascular homeostasis and then represent key players in the pathogenesis of several inflammatory and thrombotic diseases. Consequently, elucidating their role and their mechanisms of formation will bring new insights into the understanding of endothelial-associated diseases. Moreover, in the future, it can open novel therapeutic perspectives based on the inhibition of EMP release.
Thrombosis and Haemostasis 09/2010; 104(3):456-63. · 5.04 Impact Factor
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ABSTRACT: A sedentary lifestyle has adverse effects on the cardiovascular system, including impaired endothelial functions. Subjecting healthy men to 7 days of dry immersion (DI) presented a unique opportunity to analyze the specific effects of enhanced inactivity on the endothelium. We investigated endothelial properties before, during, and after 7 days of DI involving eight subjects. Microcirculatory functions were assessed with laser Doppler in the skin of the calf. We studied basal blood flow and endothelium-dependent and -independent vasodilation. We also measured plasma levels of microparticles, a sign of cellular dysfunction, and soluble endothelial factors, reflecting the endothelial state. Basal flow and endothelium-dependent vasodilation were reduced by DI (22 + or - 4 vs. 15 + or - 2 arbitrary units and 29 + or - 6% vs. 12 + or - 6%, respectively, P < 0.05), and this was accompanied by an increase in circulating endothelial microparticles (EMPs), which was significant on day 3 (42 + or - 8 vs. 65 + or - 10 EMPs/microl, P < 0.05), whereas microparticles from other cell origins remained unchanged. Plasma soluble VEGF decreased significantly during DI, whereas VEGF receptor 1 and soluble CD62E were unchanged, indicating that the increase in EMPs was associated with a change in antiapoptotic tone rather than endothelial activation. Our study showed that extreme physical inactivity in humans induced by 7 days of DI causes microvascular impairment with a disturbance of endothelial functions, associated with a selective increase in EMPs. Microcirculatory endothelial dysfunction might contribute to cardiovascular deconditioning as well as to hypodynamia-associated pathologies. In conclusion, the endothelium should be the focus of special care in situations of acute limitation of physical activity.
AJP Heart and Circulatory Physiology 08/2010; 299(2):H248-56. · 3.71 Impact Factor
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Abdeldjalil Kebir,
Karim Harhouri,
Benjamin Guillet,
Jia Wei Liu,
Alexandrine Foucault-Bertaud,
Edouard Lamy,
Elise Kaspi,
Nadia Elganfoud,
Frédéric Vely, Florence Sabatier,
José Sampol,
Pascale Pisano,
Egbert K O Kruithof,
Nathalie Bardin,
Françoise Dignat-George,
Marcel Blot-Chabaud
[show abstract]
[hide abstract]
ABSTRACT: CD146, a transmembrane immunoglobulin mainly expressed at the intercellular junction of endothelial cells, is involved in cell-cell cohesion, paracellular permeability, monocyte transmigration and angiogenesis. CD146 exists as 2 isoforms, short (sh) and long (lg), but which isoform is involved remains undefined.
The recently described role of CD146 in angiogenesis prompted us to investigate which isoform was involved in this process in human late endothelial progenitors (EPCs), with the objective of increasing their proangiogenic potential.
Immunofluorescence experiments showed that, in subconfluent EPCs, shCD146 was localized in the nucleus and at the migrating edges of the membrane, whereas lgCD146 was intracellular. In confluent cells, shCD146 was redistributed at the apical membrane and lgCD146 was directed toward the junction. In contrast to lgCD146, shCD146 was overexpressed in EPCs as compared to mature endothelial cells and upregulated by vascular endothelial growth factor and SDF-1 (stromal cell-derived factor 1). Study of the properties of both isoforms in vitro provided evidence that shCD146 was involved in EPC adhesion to activated endothelium, migration, and proliferation, with a paracrine secretion of interleukin-8 or angiopoietin 2, whereas lgCD146 was implicated in stabilization of capillary-like structures in Matrigel and transendothelial permeability. In an animal model of hindlimb ischemia, transplantation of shCD146-modified EPCs selectively promoted both EPC engraftment and blood flow.
Altogether, these findings establish that CD146 isoforms display distinct functions in vessels regeneration. Selective improvement of therapeutic angiogenesis by shCD146 overexpression suggests a potential interest of shCD146-transduced EPCs for the treatment of peripheral ischemic disease.
Circulation Research 05/2010; 107(1):66-75. · 9.49 Impact Factor
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Karim Harhouri,
Abdeldjalil Kebir,
Benjamin Guillet,
Alexandrine Foucault-Bertaud,
Serge Voytenko,
Marie-Dominique Piercecchi-Marti,
Caroline Berenguer,
Edouard Lamy,
Frédéric Vely,
Pascale Pisano,
L'houcine Ouafik, Florence Sabatier,
José Sampol,
Nathalie Bardin,
Françoise Dignat-George,
Marcel Blot-Chabaud
[show abstract]
[hide abstract]
ABSTRACT: CD146, an endothelial molecule involved in permeability and monocyte transmigration, has recently been reported to promote vessel growth. As CD146 is also detectable as a soluble form (sCD146), we hypothesized that sCD146 could stimulate angiogenesis. Experiments of Matrigel plugs in vivo showed that sCD146 displayed chemotactic activity on endogenous endothelial cells, and exogenously injected late endothelial progenitor cells (EPCs). Recruited endothelial cells participated in formation of vascular-like structures. In vitro, sCD146 enhanced angiogenic properties of EPCs, with an increased cell migration, proliferation, and capacity to establish capillary-like structures. Effects were additive with those of vascular endothelial growth factor (VEGF), and sCD146 enhanced VEGFR2 expression and VEGF secretion. Consistent with a proangiogenic role, gene expression profiling of sCD146-stimulated EPCs revealed an up-regulation of endothelial nitric oxide synthase, urokinase plasminogen activator, matrix metalloproteinase 2, and VEGFR2. Silencing membrane-bound CD146 inhibited responses. The potential therapeutic interest of sCD146 was tested in a model of hind limb ischemia. Local injections of sCD146 significantly reduced auto-amputation, tissue necrosis, fibrosis, inflammation, and increased blood flow. Together, these findings establish that sCD146 displays chemotactic and angiogenic properties and promotes efficient neovascularization in vivo. Recombinant human sCD146 might thus support novel strategies for therapeutic angiogenesis in ischemic diseases.
Blood 02/2010; 115(18):3843-51. · 9.90 Impact Factor
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ABSTRACT: The reversibility of pulmonary arterial hypertension (PAH) in children with congenital heart disease (CHD) is strongly associated with the degree of intimal proliferation, vessel narrowing, and number of circulating endothelial cells (CECs). Circulating endothelial cells may arise from either endothelial damage or accelerated turnover during vessel remodeling, but nothing is known about endothelial microparticles (EMPs) and other biomarkers reflecting endothelial alterations. This study aimed to document endothelial markers further according to the irreversibility of PAH secondary to CHD. The study investigated soluble markers of endothelial damage or activation (thrombomodulin, soluble endothelial protein C receptor, and soluble E-selectin), inflammation (interleukin-6), and angiogenic cytokine levels [vascular endothelial growth factor (VEGF) and placental growth factor (PlGF)] in 26 patients with CHD, 16 with reversible PAH (median age, 2 years) and 10 with irreversible PAH (median age, 9 years). Endothelial activation/apoptosis was evaluated by measuring EMP levels. Plasma procoagulant activity also was measured. The results show that the levels of soluble markers indicating endothelial activation were not predictors of PAH irreversibility. Lower levels of PlGF were observed in reversible compared with irreversible PAH but were not associated with the CEC level, the mean pulmonary artery pressure (mPAP), or age. No significant difference in procoagulant activity or EMP level was found between irreversible and reversible PAH. Among a large panel of biomarkers reflecting endothelial activation, regeneration, and injury, the high CEC levels previously described proved to be the only marker allowing discrimination between reversible and irreversible PAH secondary to CHD.
Pediatric Cardiology 02/2010; 31(5):657-62. · 1.30 Impact Factor
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ABSTRACT: Inflammatory activation of the vascular endothelium is a major contributory factor to ischemic cardiovascular disease. Endothelial progenitor cells (EPCs) are being investigated for the treatment of ischemic disease or to coat vein grafts for bypass surgery. As an inflammatory environment might reduce their therapeutic efficacy, we sought to generate EPCs that are less sensitive to inflammatory activation. EPCs were obtained from human umbilical cord blood and transduced with a lentiviral vector for stable expression of A20, an anti-inflammatory protein. Nontransduced and green-fluorescent-protein-transduced cells were used as controls. Expression of A20 by EPCs did not modify cell morphology or expression of a panel of 20 proteins known to contribute to angiogenesis. Also, A20 had no effect on the capacity of EPCs to form tube-like structures in Matrigel. A20 expression reduced EPC activation by tumor necrosis factor-alpha and interleukin-1beta as determined from changes in vascular cell adhesion molecule 1 and E-selectin expression and decreased monocyte transmigration through a monolayer of EPCs. In conclusion, EPCs can be genetically modified to overexpress A20 in a stable fashion. These cells become less sensitive to inflammatory stimuli. This may be of interest in cell-based therapeutic approaches for clinical settings where inflammation is an important pathogenic factor.
Journal of Vascular Research 10/2009; 47(2):157-67. · 2.65 Impact Factor
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Nathalie Bardin,
Marcel Blot-Chabaud,
Nicolas Despoix,
Abdeldjalil Kebir,
Karim Harhouri,
Jean-Pierre Arsanto,
Leon Espinosa,
Pierre Perrin,
Stéphane Robert,
Frédéric Vely, Florence Sabatier,
André Le Bivic,
Gilles Kaplanski,
José Sampol,
Françoise Dignat-George
[show abstract]
[hide abstract]
ABSTRACT: During inflammation, cell adhesion molecules are modulated or redistributed for leukocyte transmigration. Among molecules at the interendothelial junction, CD146 is involved in cell-cell cohesion and permeability, but its role in monocyte transmigration is unknown.
TNF enhanced CD146 expression at the junction and apical membrane of human umbilical veins endothelial cells (HUVECs) through CD146 synthesis and intracellular store redistribution. In addition, TNF increased the release of a soluble form (sCD146) through a metalloproteinase-dependent mechanism. The redistribution of CD146 to the junction led us to investigate its role in monocyte transmigration using THP1 and freshly isolated monocytes. Evidence that CD146 contributes to monocyte transmigration was provided by inhibition experiments using anti-CD146 antibodies and CD146 siRNA in HUVECs. In addition, sCD146 specifically bound both monocytes and HUVECs and dose-dependently increased monocyte transmigration. Assessment of sCD146 binding on immobilized CD146 failed to evidence any homophilic interaction. Together, our data suggest endothelial CD146 binds heterophilically with a yet unknown ligand on monocytes.
Our results demonstrate that CD146 is regulated by the inflammatory cytokine TNF and that CD146 and sCD146 are both involved in monocyte transendothelial migration during inflammation.
Arteriosclerosis Thrombosis and Vascular Biology 03/2009; 29(5):746-53. · 6.37 Impact Factor
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Céline Mias,
Elodie Trouche,
Marie-Hélène Seguelas,
Fabien Calcagno,
Françoise Dignat-George, Florence Sabatier,
Marie-Dominique Piercecchi-Marti,
Laurent Daniel,
Pascale Bianchi,
Denis Calise,
Philippe Bourin,
Angelo Parini,
Daniel Cussac
[show abstract]
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ABSTRACT: Bone marrow mesenchymal stem cells (MSCs) have shown great potential in cell therapy of solid organs. Approaches to improving the ability of grafted MSCs to survive and secrete paracrine factors represent one of the challenges for the further development of this novel therapy. In the present study, we designed a strategy of ex vivo pretreatment with the pineal hormone melatonin to improve survival, paracrine activity, and efficiency of MSCs. Using a rat model of acute renal failure, we showed that melatonin pretreatment strongly increased survival of MSCs after intraparenchymal injection. This effect was concomitant with overstimulation of angiogenesis, proliferation of renal cells, and accelerated recovery of renal function. To gain insight into the mechanisms involved in the effects observed in vivo, melatonin was tested in vitro on cultured MSCs. Our results show that through stimulation of specific melatonin receptors, melatonin induced an overexpression of the antioxidant enzyme catalase and superoxide dismutase-1 and increased the resistance of MSCs to hydrogen peroxide-dependent apoptosis. Compared with untreated cells, MSCs incubated with melatonin displayed a higher expression of basic fibroblast growth factor and hepatocyte growth factor. In addition, conditioned culture media from melatonin-treated MSCs stimulated tube formation by endothelial progenitor cells and proliferation of proximal tubule cells in culture. In conclusion, our results show that melatonin behaves as a preconditioning agent increasing survival, paracrine activity, and efficiency of MSCs. The use of this molecule for pretreatment of stem cells may represent a novel and safe approach to improving the beneficial effects of cell therapy of solid organs.
Stem Cells 06/2008; 26(7):1749-57. · 7.78 Impact Factor
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Céline Mias,
Elodie Trouche,
Marie-Hélène Seguelas,
Fabien Calcagno,
Françoise Dignat-George, Florence Sabatier,
Marie-Dominique Piercecchi-Marti,
Laurent Daniel,
Pascale Bianchi,
Denis Calise,
Philippe Bourin,
Ph.D. Angelo Parini M.D,
Daniel Cussac
[show abstract]
[hide abstract]
ABSTRACT: Bone marrow mesenchymal stem cells (MSCs) have shown great potential in cell therapy of solid organs. Approaches to improving the ability of grafted MSCs to survive and secrete paracrine factors represent one of the challenges for the further development of this novel therapy. In the present study, we designed a strategy of ex vivo pretreatment with the pineal hormone melatonin to improve survival, paracrine activity, and efficiency of MSCs. Using a rat model of acute renal failure, we showed that melatonin pretreatment strongly increased survival of MSCs after intraparenchymal injection. This effect was concomitant with overstimulation of angiogenesis, proliferation of renal cells, and accelerated recovery of renal function. To gain insight into the mechanisms involved in the effects observed in vivo, melatonin was tested in vitro on cultured MSCs. Our results show that through stimulation of specific melatonin receptors, melatonin induced an overexpression of the antioxidant enzyme catalase and superoxide dismutase-1 and increased the resistance of MSCs to hydrogen peroxide-dependent apoptosis. Compared with untreated cells, MSCs incubated with melatonin displayed a higher expression of basic fibroblast growth factor and hepatocyte growth factor. In addition, conditioned culture media from melatonin-treated MSCs stimulated tube formation by endothelial progenitor cells and proliferation of proximal tubule cells in culture. In conclusion, our results show that melatonin behaves as a preconditioning agent increasing survival, paracrine activity, and efficiency of MSCs. The use of this molecule for pretreatment of stem cells may represent a novel and safe approach to improving the beneficial effects of cell therapy of solid organs.Disclosure of potential conflicts of interest is found at the end of this article.
Stem Cells 05/2008; 26(7):1749 - 1757. · 7.78 Impact Factor
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ABSTRACT: Sedentary behavior has deleterious effects on the cardiovascular system, including reduced endothelial functions. A 2-mo bed rest study in healthy women [women international space simulation for exploration (WISE) 2005 program] presented a unique opportunity to analyze the specific effects of prolonged inactivity without other vascular risk factors on the endothelium. We investigated endothelial properties before and after 56 days of bed rest in 8 subjects who performed no exercise (control group: No-EX) and in 8 subjects who regularly performed treadmill exercise in a lower body negative pressure chamber as well as resistance exercise (countermeasure group, EX). A functional evaluation of the microcirculation in the skin was assessed with laser Doppler. We studied endothelium-dependent and -independent vasodilation using iontophoresis of acetylcholine and sodium nitroprusside, respectively. We also measured circulating endothelial cells (CECs), an index of endothelial damage. In the No-EX group, endothelium-dependent vasodilation was significantly reduced (35.4 +/- 4.8% vs. 24.1 +/- 3.8%, P < 0.05) by bed rest with a significant increase in the number of CECs (3.6 +/- 1.4 vs. 10.6 +/- 2.7 ml(-1), P < 0.05). In the EX group, endothelium-dependent vasodilation and number of CECs were preserved. Our study shows that in humans prolonged bed rest causes impairment of endothelium-dependent function at the microcirculatory level, along with an increase in circulating endothelial cells. Microcirculatory endothelial dysfunction might participate in cardiovascular deconditioning, as well as in several bed rest-induced pathologies. We therefore conclude that the endothelium should be a target for countermeasures during periods of prolonged deconditioning.
AJP Heart and Circulatory Physiology 12/2007; 293(5):H3159-64. · 3.71 Impact Factor
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Romaric Lacroix, Florence Sabatier,
Agnès Mialhe,
Agnès Basire,
Ralph Pannell,
Hélène Borghi,
Stephane Robert,
Edouard Lamy,
Laurent Plawinski,
Laurence Camoin-Jau,
Victor Gurewich,
Eduardo Angles-Cano,
Françoise Dignat-George
[show abstract]
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ABSTRACT: The regulation of plasmin generation on cell surfaces is of critical importance in the control of vascular homeostasis. Cell-derived microparticles participate in the dissemination of biological activities. However, their capacity to promote plasmin generation has not been documented. In this study, we show that endothelial microparticles (EMPs) from tumor necrosis factor alpha (TNFalpha)-stimulated endothelial cells served as a surface for the generation of plasmin. The generation of plasmin involved expression of urokinase-type plasminogen activator (uPA) and its receptor (uPAR) at the surface of EMPs and was further increased by their ability to bind exogenous uPA on uPAR. Plasminogen was activated at the surface of EMPs in a dose-dependent, saturable, and specific manner as indicated by the inhibition of plasmin formation by epsilon-amino-caproic acid (epsilon-ACA) and carboxypeptidase B. EMP-induced plasmin generation affects tube formation mediated by endothelial progenitor cells. However, low amounts of EMPs increased tube formation, whereas higher concentrations inhibited it. Prevention of these effects by inhibitors of either uPA or plasmin underscore the key role of EMP-induced plasmin generation. In conclusion, we demonstrated that EMPs act as vectors supporting efficient plasmin generation and dissemination, a new pathway in the regulation of endothelial proteolytic activities with potential involvement in inflammation, angiogenesis, and atherosclerosis.
Blood 11/2007; 110(7):2432-9. · 9.90 Impact Factor
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Journal of Clinical Oncology 03/2007; 25(5):e1-2; author reply e3-5. · 18.37 Impact Factor
