Accueil > Agenda > Les séminaires Jean Roche > Cellules endothéliales circulantes et microparticules : une signature de (...)

Cellules endothéliales circulantes et microparticules : (...)

Lundi 6 février,11h, salle Lissitzky.


1 : Inflamm Bowel Dis. 2006 Jan ;12(1):16-21.

Increased expression of CD146, a new marker of the endothelial junction in active inflammatory bowel disease.

Bardin N, Reumaux D, Geboes K, Colombel JF, Blot-Chabaud M, Sampol J, Duthilleul P, Dignat-George F.

INSERM U608, Physiopathologie de l’Endothelium, Universite de la Mediterranee, UFR Pharmacie, Marseille, France. bardin

BACKGROUND : Crohn’s disease (CD) and ulcerative colitis (UC), the 2 major forms of inflammatory bowel diseases (IBD), have been associated with disturbances in vascular physiology, including permeability and angiogenesis, that are in part regulated by the endothelial intercellular junctions. These junctions are composed of several adhesion molecules including the platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31) and the more recently described CD146 (S-Endo1 Ag, MUC18). AIM : To study the expression of tissue and soluble form of CD146 in patients with CD or UC in relation to disease activity and location. This study was made in comparison with the soluble form of CD31 (sCD31). RESULTS : In active disease, a high expression of CD146 was observed on endothelial cells in intestinal biopsies from both CD and UC. In addition, we observed a decrease of sCD146 in relation to active disease and extensive location of CD and UC. Lower levels of sCD31 were also detected in active and extensive location of UC, but no difference could be observed in CD. CONCLUSION : sCD146 is a novel marker of the endothelial intercellular junction that reflects endothelial remodeling more effectively than soluble CD31. Further studies are warranted to determine whether sCD146 will provide a serological assay reflecting alterations in vascular permeability and vessel proliferation in the inflamed IBD intestine.

PMID : 16374253 [PubMed - in process]

2 : J Thromb Haemost. 2005 Dec 23 ; [Epub ahead of print] Related Articles, Links

Elevation of circulating endothelial microparticles in patients with chronic renal failure.

Faure V, Dou L, Sabatier F, Cerini C, Sampol J, Berland Y, Brunet P, Dignat-George F.

INSERM U608, UFR de Pharmacie, Universite de la Mediterranee, Marseille, France.

Summary. Background : Chronic renal failure patients are at high risk of cardiovascular events and display endothelial dysfunction, a critical element in the pathogenesis of atherosclerosis. Upon activation, the endothelium sheds microparticles, considered as markers of endothelial dysfunction that also behave as vectors of bioactive molecules. Aim : To measure plasma levels of endothelial microparticles (EMPs) in chronic renal failure patients (CRF), either undialyzed or hemodialyzed (HD), and to investigate the ability of uremic toxins to induce EMP release in vitro. Methods : Circulating EMPs were numerated by flow cytometry, after staining of platelet-free plasma with phycoerythrin (PE)-conjugated anti-CD144 (CD144+ EMP) or anti-CD146 (CD146+ EMP) monoclonal antibodies. Platelet MP (CD41+ PMP), leukocyte MP (CD45+ leukocyte microparticles (LMP)), and annexin-V+ MPs were also counted. In parallel, MPs were counted in supernatant of human umbilical vein endothelial cells incubated with uremic toxins [oxalate, indoxyl sulfate, p-cresol, and homocysteine (Hcy)], at concentrations found in patients. Results and conclusions : CD144+ EMP and CD146+ EMP levels were significantly higher in CRF and HD patients than in healthy subjects. Furthermore, annexin-V+ MPs were elevated in both groups of uremic patients, and CD41+ PMP and CD45+ LMP were increased in CRF and HD patients, respectively. In vitro, p-cresol and indoxyl sulfate significantly increased both CD146+ and annexin-V+ EMP release. Increased levels of circulating EMP in CRF and HD patients represent a new marker of endothelial dysfunction in uremia. The ability of p-cresol and indoxyl sulfate to increase EMP release in vitro suggests that specific uremic factors may be involved in EMP elevation in patients.

PMID : 16405517 [PubMed - as supplied by publisher]

3 : Rev Med Interne. 2005 Dec 9 ; [Epub ahead of print] Related Articles, Links

[NK cells : new insights on physiology and clinical implication in diseases.]

[Article in French]

Schleinitz N, Hamidou M, Vely F, Paul P, Figarella-Branger D, Kaplanski G, Dignat-George F, Vivier E, Harle JR.

Service de medecine interne, CHU Conception, boulevard Baille, 13385 Marseille cedex 05, France.

Introduction. - Natural killer cells are cytotoxic lymphocytes of innate immunity. These last ten years our knowledge about the mechanisms that regulates NK cell function has greatly improved. Our purpose is to present a review of these new acquisitions and their potential implications in human disease. Current knowledge and key points. - NK cell function is regulated by a repertoire of NK cell receptors and is diversified by recognition of MHC class I by a multigenic and mutiallelic family of NK receptors. Analysis of NK cell repertoire has been used to investigate features that characterize NK cells in pathological situations. Apart from their direct cytotoxic potential to eliminate target cells, recently identification of mechanisms that control NK cell mediated cytokine production and cross talk with dendritic cells emphasize the role of NK cells in the regulation of acquired immune response. Future prospects and projects. - These findings have lead to a better knowledge of the importance of the NK cells in several human diseases. It has been shown that NK cells are actors of the immunosurveillance of tumoral and infectious challenges. Allo or auto reactivity of the NK cell compartment have also been suggested in autoimmune diseases, infertility or foetal loss and transplantation. Ongoing research on NK cells in the fields of human diseases is increasing and will clarify the utility of the evaluation of the NK cell compartment and their receptors in clinical practice.

PMID : 16368165 [PubMed - as supplied by publisher]

4 : Thromb Haemost. 2005 Dec ;94(6):1280-4. Related Articles, Links The first assessment of soluble CD146 in women with unexplained pregnancy loss. A new insight ?

Pasquier E, Bardin N, De Saint Martin L, Le Martelot MT, Bohec C, Roche S, Mottier D, Dignat-George F.

EA 3878 (GETBO), Brest University Hospital, Brest, France. elisabeth.pasquier

The mechanisms responsible for pregnancy loss have not all been elucidated. CD146 is a cell adhesion molecule involved in the control of both endothelium integrity and intermediate trophoblast invasiveness, two potential key features in the pathogenesis of pregnancy loss. As CD146 is detectable as a soluble form in the plasma (sCD146), we investigated sCD146 plasma levels in women with a history of pregnancy loss. We conducted a paired case-control study to compare sCD146 plasma levels in 100 women with unexplained pregnancy losses (2 or more consecutive losses at or before 21 weeks of gestation, or at least one later loss) and in 100 age-matched control women (no pregnancy loss and at least one living child). The sCD146 concentrations were determined at least 2 months after the last obstetrical event. Patients and controls were comparable regarding thrombophilia. Among the patients, 83 women experienced early pregnancy losses (average of 3 losses, mean gestation of 6.6 weeks) and 22 women suffered at least one late pregnancy loss. We found significantly higher sCD146 plasma levels in the 100 patients compared to age matched control women (p < 0.001). The sCD146 plasma levels did not correlate with the number of pregnancy losses nor with the mean gestation time. Alterations in sCD 146 plasma levels could be related to endothelial dysfunction associated to defective endovascular trophoblast invasiveness. Additional studies should explore whether sCD146 assessment could provide diagnostic and prognostic information with a view to screening and thus managing women with unexplained pregnancy loss.

PMID : 16411406 [PubMed - in process]

5 : Thromb Haemost. 2005 Dec ;94(6):1270-9. Related Articles, Links Presence of endothelial progenitor cells, distinct from mature endothelial cells, within human CD146+ blood cells.

Delorme B, Basire A, Gentile C, Sabatier F, Monsonis F, Desouches C, Blot-Chabaud M, Uzan G, Sampol J, Dignat-George F.

INSERM Unite 608, Laboratoire d’Hematologie et d’Immunologie, UFR de Pharmacie, Universite de la Mediterranee, Marseille, France.

CD146 is an adhesion molecule present on endothelial cells throughout the vascular tree. CD146 is also expressed by circulating endothelial cells (CECs) widely considered to be mature endothelial cells detached from injured vessels. The discovery of circulating endothelial progenitor cells (EPCs) originating from bone marrow prompted us to investigate whether CD146 circulating cells could also contains EPCs. We tested this hypothesis using an approach combining elimination of CECs by an adhesion step, followed by immunomagnetic sorting of remaining CD146+ cells from the non adherent fraction of cord blood mononuclear cells. When cultured under endothelial-promoting conditions, these cells differentiated as late outgrowth endothelial colonies : they grew as a cobblestone monolayer, were uniformly positive for endothelial markers and did not express leukocyte antigens. They highly proliferated and were expanded in long-term culture without alterations of their phenotypic and functional properties (Dil-ac-LDL uptake, wound repair, capillary-like network formation, and TNFalpha response). Moreover, these cells colonized a Matrigel plug in immunodeficient mice (NOD/SCID). Finally, using 4-color flow cytometry analysis of purified CD34+ cells, we clearly discriminated, CD146+ EPCs (CD146+ CD34+ CD45+ CD133+ or CD117+), and CD146+ CECs (CD146+ CD34+, CD45- CD133- or CD117-), both in cord and adult peripheral blood.The relative proportions of the two CD146+ subsets varied in patients with myocardial infarction as compared to healthy subjects. Our study establishes that, beside CECs, CD146+ circulating cells contain a subpopulation of EPCs with potential use in proangiogenic therapy. In addition, the dual measurement of CD146+ CECs and CD146+ EPCs offers a promising tool for monitoring vascular injury/regeneration processes in clinical situations.

PMID : 16411405 [PubMed - in process]

6 : Int Immunol. 2005 Apr ;17(4):489-500. Epub 2005 Mar 4. Related Articles, Links

Role of reactive oxygen species and p38 MAPK in the induction of the pro-adhesive endothelial state mediated by IgG from patients with anti-phospholipid syndrome.

Simoncini S, Sapet C, Camoin-Jau L, Bardin N, Harle JR, Sampol J, Dignat-George F, Anfosso F.

INSERM U608 Physiopathologie de l’Endothelium, Universite de la Mediterranee, UFR de Pharmacie, 27 Bd Jean Moulin, 13385 Marseille Cedex 5, France.

The association of the presence of anti-phospholipid antibodies (aPL) with thrombosis characterizes the anti-phospholipid syndrome (APS). The activation of the endothelium is a key event in the establishment of the thrombophilic state. However, the intracellular mechanisms leading to endothelial dysfunction are not fully elucidated. We investigated the role of reactive oxygen species (ROS) in the pro-adhesive state elicited by aPL and studied ROS-dependent downstream signaling pathways. Independent incubation of human umbilical vein endothelial cells (HUVEC) with IgG (IgG-APS) from 12 APS patients caused a large and sustained increase in ROS, which was prevented by the antioxidants vitamin C and N-acetyl-L-cysteine. ROS inhibition observed in the presence of diphenylene iodonium and rotenone indicated an involvement of a membrane-bound oxidase and the mitochondrial transport chain as sources of ROS. ROS acted as a second messenger by activating the p38 mitogen-activated protein kinase and its subsequent target, the stress-related transcription factor activating transcription factor-2 (ATF-2). ROS controlled the up-regulation of vascular cell adhesion molecule-1 expression by IgG-APS-stimulated HUVEC and the increase in THP-1 monocytic cells adhesion. The IgG-APS-mediated oxidative stress was observed irrespective of the clinical and biological criterions of the patients studied here. Taken together, these data indicate that the oxidative stress induced by IgG-APS is a key intracellular event that might contribute to the thrombotic complications of APS by controlling the endothelial adhesive phenotype.

PMID : 15749729 [PubMed - indexed for MEDLINE]

7 : J Thromb Haemost. 2005 Mar ;3(3):613-4. Related Articles, Links

Comment on : J Thromb Haemost. 2004 Oct ;2(10):1842-3.

More on : Measuring circulating cell-derived microparticles.

Freyssinet JM, Dignat-George F.

Publication Types : Comment Letter

PMID : 15748272 [PubMed - indexed for MEDLINE]

8 : Thromb Haemost. 2005 Feb ;93(2):228-35. Related Articles, Links

Circulating endothelial cells. Biomarker of vascular disease.

Blann AD, Woywodt A, Bertolini F, Bull TM, Buyon JP, Clancy RM, Haubitz M, Hebbel RP, Lip GY, Mancuso P, Sampol J, Solovey A, Dignat-George F.

Haemostasis Thrombosis and Vascular Biology Unit, University Department of Medicine, City Hospital, Birmingham, B18 7QH, UK. a.blann

Recent research has recognised new populations of non-hematopoietic cells in the blood. One of these, circulating endothelial cells (CECs), often defined by the expression of membrane glycoprotein CD146, are rarely found in the blood in health, but raised numbers are present in a wide variety of human conditions, including inflammatory, immune, infectious, neoplastic and cardiovascular disease, and seem likely to be evidence of profound vascular insult. An additional population are endothelial progenitor cells, defined by the co-expression of endothelial and immaturity cell surface molecules and also by the ability to form colonies in vitro. Although increased numbers of CECs correlate with other markers of vascular disease, questions remain regarding the precise definition, cell biology and origin of CECs. For example, they may be damaged, necrotic or apopototic, or alive, and could possess procoagulant and/or proinflammatory properties. However, since these cells seem to be representative of in situ endothelium, their phenotype may provide useful information. Indeed, whatever their phenotype, there is growing evidence that CECs may well be a novel biomarker, the measurement of which will have utility in various clinical settings related to vascular injury. Despite this promise, progress is impeded by the diversity of methodologies used to detect these cells. Accordingly, results are sometimes inconclusive and even conflicting. Nevertheless, increased CECs predict adverse cardiovascular events in acute coronary syndromes, suggesting they may move from being simply a research index to having a role in the clinic. The objective of the present communication is to condense existing data on CECs, briefly compare them with progenitor cells, and summarise possible mechanism(s) by which they may contribute to vascular pathology.

Publication Types : Review

PMID : 15711737 [PubMed - indexed for MEDLINE]

9 : Nephron Exp Nephrol. 2005 ;99(4):e105-11. Epub 2005 Feb 8. Related Articles, Links

Tubular CD146 expression in nephropathies is related to chronic renal failure.

Daniel L, Bardin N, Moal V, Dignat-George F, Berland Y, Figarella-Branger D.

EA 3281, Faculty of Medicine, Marseille, France. laurent.daniel

BACKGROUND : CD146, a member of the immunoglobulin superfamily, is mainly expressed at the endothelial junction. The soluble form of CD146 is increased in the serum of patients with chronic renal failure. The aim of the study was to investigate CD146 expression on biopsies of normal kidney and nephropathies. METHODS : We did an immunohistochemical analysis of 10 normal renal tissues and 126 patients with nephropathies. RESULTS : The mean age of the patients was 47.5 +/- 18 years with 65% of men. At the time of the biopsy, 73 patients (57.9%) had a renal failure and the mean proteinuria was 3.3 +/- 2.9 g/24 h. Inflammatory syndrome was present in 60 (47.6%) patients. Fibrous interstitial changes from minimal lesions to diffuse lesions were seen in 105 (83.3%) biopsies ; the mean glomerulosclerosis index was 16.9 +/- 19.7%. Normal kidneys showed CD146 staining on endothelial cells, smooth muscle cells, and mesangium. Normal tubular cells were not stained. If endocapillary proliferation was present, the mesangial CD146 expression was higher. This mesangial expression correlated with proteinuria (p = 0.007) and not with renal failure (p = 0.07). A de novo expression on tubular cells was found in 53 patients (42%) and this expression correlated with age (p < 0.001), male sex (p = 0.04), glomerulosclerosis (p < 0.001), interstitial fibrosis (p < 0.001), and renal failure (p < 0.001). CONCLUSION : Renal CD146 expression is of interest for determining the pathogenesis of mesangial alterations during glomerular injuries and of tubular phenotypic changes during chronic renal failure.

PMID : 15703461 [PubMed - in process]

10 : Thromb Haemost. 2005 Jan ;93(1):80-7. Related Articles, Links

Erratum in : Thromb Haemost. 2005 Apr ;93(4):796-7.

Heterogeneity of anti-beta2-glycoprotein I antibodies. A factor of variability in test results.

Sanmarco M, Bardin N, Blank M, Pascal V, Christine Alessi M, Dignat-George F, Shoenfeld Y, Harle JR.

Federation Autoimmunite et Thrombose, Laboratoire d’Immunologie Hopital de La Conception, 147 Bd Baille, 13385 Marseille cedex 05, France. marielle.sanmarco

The aim of this study was to evaluate the heterogeneity of IgGanti-beta2-glycoprotein I antibodies (IgG-abeta2GPI) as regarding their reactivity pattern against different sources of human beta2 GPI, their avidity and their association with clinical events of antiphospholipid syndrome (APS). Three thousand six hundred and eighty-four consecutive patient sera were routinely tested for IgGabeta2 GPI over 1 year using an in-house ELISA with 2 different commercial preparations of human purified beta2GPI. Of the 340 sera found positive, all those clinically documented were included in this study ; 61 were positive with only one preparation (S1) and 59 with both (S2). The results of ELISA were confirmed by Western blot. Heterogeneity was stressed by testing sera with a human recombinant protein and 3 beta2GPI-related peptides. No contribution of glycosylation in the binding to beta2GPI was found. The avidity indices for each protein were significantly higher in S1 than in S2 (p=0.0021). S2 were more associated with antiphospholipid antibodies than S1 (75% versus 21% ; p<0.0001). A similar frequency of the main clinical features of APS was found in S1 and S2 sera (69% and 71%, respectively). In conclusion, our data show a heterogeneity in the antigenic reactivity pattern of IgG- abeta2 GPI and a relationship between a binding profile and antibody avidity. This heterogeneity could represent a crucial factor of variability in test results and underlines the difficulty of getting standardisation.

Publication Types : Multicenter Study

PMID : 15630495 [PubMed - indexed for MEDLINE]

11 : Eur J Immunol. 2004 Oct ;34(10):2930-40. Related Articles, Links

Comparative analysis of NK cell subset distribution in normal and lymphoproliferative disease of granular lymphocyte conditions.

Pascal V, Schleinitz N, Brunet C, Ravet S, Bonnet E, Lafarge X, Touinssi M, Reviron D, Viallard JF, Moreau JF, Dechanet-Merville J, Blanco P, Harle JR, Sampol J, Vivier E, Dignat-George F, Paul P.

Centre d’Immunologie Marseille-Luminy, INSERM-CNRS-Universite Mediterranee, Marseille, France.

We have characterized the heterogeneity of human blood NK cell subsets defined by expression of KIR, lectin like receptors and NK cell differentiation markers within a cohort of 51 healthy Caucasian individuals. High inter-individual variability in cell surface expression of most NK cell markers is observed. Range values defining NK cell subsets in healthy donors were further used as references to characterize 14 patients with NK-type lymphoproliferative disease of granular lymphocytes (NK-LDGL). Alterations of the KIR repertoire were noted in all NK-LDGL patients. NK cell expansions were classified as oligoclonal KIR(+) or as non-detectable KIR ((nd)KIR) using anti-KIR2DL1/2DS1, anti-KIR2DL2/2DL3/2DS2, anti-KIR3DL1 and anti-KIR2DS4 monoclonal antibodies. A major reduction in the size of the CD56(bright) NK cell subset was a constant feature of NK-LDGL. Altered distribution of CD94(+), CD161(+), and CD162R(+) NK cell subsets was also observed in NK-LDGL patients. Considering the potential role of NK cells in eliminating tumors or virus-infected cells, the reference values defined in this study should be valuable to characterize both quantitative and qualitative alterations of the NK cell repertoire in pathological conditions and to monitor NK cell reconstitution following hematopoietic transplantation.

PMID : 15368309 [PubMed - indexed for MEDLINE]

12 : J Thromb Haemost. 2004 Oct ;2(10):1842-3. Related Articles, Links

Comment in : J Thromb Haemost. 2005 Mar ;3(3):613-4.

Measuring circulating cell-derived microparticles.

Jy W, Horstman LL, Jimenez JJ, Ahn YS, Biro E, Nieuwland R, Sturk A, Dignat-George F, Sabatier F, Camoin-Jau L, Sampol J, Hugel B, Zobairi F, Freyssinet JM, Nomura S, Shet AS, Key NS, Hebbel RP.

The Wallace H. Coulter Platelet Laboratory, Department of Medicine, University of Miami School of Medicine, Miami, Florida, USA. wjy

PMID : 15456497 [PubMed - indexed for MEDLINE]

13 : Circulation. 2004 Sep 21 ;110(12):1586-91. Epub 2004 Sep 13. Related Articles, Links

Circulating endothelial cell count as a diagnostic marker for non-ST-elevation acute coronary syndromes.

Quilici J, Banzet N, Paule P, Meynard JB, Mutin M, Bonnet JL, Ambrosi P, Sampol J, Dignat-George F.

Departement de Cardiologie, Hopital Timone Adultes, Marseille, France.

BACKGROUND : Shedding of endothelial cells from damaged endothelium into the blood occurs in a variety of vascular disorders. The purpose of this study was to evaluate the utility of circulating endothelial cell (CEC) count as a diagnostic marker of non-ST-elevation acute coronary syndromes (ACSs). METHODS AND RESULTS : CEC counts were determined immediately (H0), 4 hours (H4), and 8 hours (H8) after admission in 60 patients with documented non-ST-elevation ACS and 40 control patients with no evidence of coronary artery disease. A total of 32 patients in the ACS group had elevated CEC counts (>3 cells/mL) in relation to early admission and single-episode chest pain. Patients from the control group had normal CEC counts. The interval between the chest pain episode and elevation was significantly shorter for CEC than troponin I. No correlation was found between the 2 markers. Interestingly, a subgroup of ACS patients with initially normal troponin I levels had high CEC counts, thus allowing early diagnosis in 30% more cases. At H0, the mean area under the receiver operating characteristic curve was significantly higher with the CEC count than with the troponin I level. At H4 and H8, the combined use of CEC and troponin was significantly better as a marker of ACS than CEC alone or troponin I alone. CONCLUSIONS : This study demonstrates that CEC count can be used as an early, specific, independent diagnostic marker for non-ST-elevation ACS. A combined strategy using CEC count and troponin I level could provide an effective diagnostic tool.

PMID : 15364807 [PubMed - indexed for MEDLINE]

14 : Thromb Haemost. 2004 Jul ;92(1):140-50. Related Articles, Links

P-cresol, a uremic retention solute, alters the endothelial barrier function in vitro.

Cerini C, Dou L, Anfosso F, Sabatier F, Moal V, Glorieux G, De Smet R, Vanholder R, Dignat-George F, Sampol J, Berland Y, Brunet P.

INSERM EMI0019, Faculte de Pharmacie, Universite e la Mediterranee, 27 bld Jean Moulin, 13385 Marseille, Cedex 5, France. claire.cerini

Patients with chronic renal failure (CRF) exhibit endothelial dysfunction, which may involve uremic retention solutes that accumulate in blood and tissues. In this study, we investigated the in vitro effect of the uremic retention solute p-cresol on the barrier function of endothelial cells (HUVEC). P-cresol was tested at concentrations found in CRF patients, and since p-cresol is protein-bound, experiments were performed with and without physiological concentration of human albumin (4 g/dl). With albumin, we showed that p-cresol caused a strong increase in endothelial permeability after a 24-hour exposure. Concomitant with this increase in endothelial permeability, p-cresol induced a reorganization of the actin cytoskeleton and an alteration of adherens junctions. These molecular events were demonstrated by the decreased staining of cortical actin, associated with the formation of stress fibers across the cell, and by the decreased staining of junctional VE-cadherin. This decrease in junctional VE-cadherin staining was not associated with a reduction of membrane expression. Without albumin, the effects of p-cresol were more pronounced.The specific Rho kinase inhibitor, Y-27632, inhibited the effects of p-cresol, indicating that p-cresol mediates the increase in endothelial permeability in a Rho kinase-dependent way. In conclusion, these results show that p-cresol causes a severe dysfunction of endothelial barrier function in vitro and suggest this uremic retention solute may participate in the endothelium dysfunction observed in CRF patients.

PMID : 15213855 [PubMed - indexed for MEDLINE]

15 : Gynecol Obstet Fertil. 2004 Jun ;32(6):482-9. Related Articles, Links

[New insight in physiopathology of preeclampsia and intra-uterine growth retardation : role of inflammation]

[Article in French]

Bretelle F, Sabatier F, Shojai R, Agostini A, Dignat-George F, Blanc B, d’Ercole C.

Service de gynecologie-obstetrique, hopital de la Conception, 147, boulevard Baille, 13385 Marseille 5, France. florence.bretelle

Inflammatory response is a major component in physiopathology of preeclampsia and intra-uterine growth retardation. Endothelium is a main connection between placental ischemia and clinical manifestations during vascular pregnancy complications. In this review recent findings concerning inflammatory response and its links with endothelium are reported. Studies concerning isolated intra-uterine growth retardation confirm the hypothesis of a similar pathophysiology with an activation confined to utero-placental bed or at a lower level. Current information on oxidative stress, atherosclerosis, and apoptosis in vascular pregnancy complications are available in this review. These concepts offer innovative possibilities of treatment.

Publication Types : Review

PMID : 15217562 [PubMed - indexed for MEDLINE]

16 : Shock. 2004 Apr ;21(4):311-4. Related Articles, Links

Cell adhesion molecules as a marker reflecting the reduction of endothelial activation induced by glucocorticoids.

Leone M, Boutiere-Albanese B, Valette S, Camoin-Jau L, Barrau K, Albanese J, Martin C, Dignat-George F.

Department of Anesthesiology and Intensive Care Medicine, Marseilles Nord University Hospital System, Marseilles School of Medicine, 13005 Marseille, France. leonem

In vitro, steroids down-regulate the expression of cell adhesion molecules (CAMs) in endothelial cells stimulated by lipopolysaccharide. Low-dose hydrocortisone is a new treatment of patients with septic shock, a state that is characterized by an endothelial injury. The aim of the present study was to investigate whether the plasma levels of soluble CAMs, reflecting in vivo endothelial activation, could be modulated in patients with septic shock treated by hydrocortisone. This was a prospective and observational study conducted in the intensive care unit at a university hospital. The subjects included 40 patients with septic shock (American College of Chest Physicians Consensus Conference/Society of Critical Care Medicine definition) ; 45 healthy blood donors served as controls. The patients receiving the standard care ("reference group") during the first 6 months were compared with the patients receiving the hydrocortisone therapy ("hydrocortisone group") for the next 6 months. Measurements of sCAMs were performed on days 1 and 3 of the disease. On day 1, sE-selectin, sP-selectin, sVCAM-1, and sICAM-1 were significantly elevated in patients with septic shock compared with healthy donors. sE-selectin levels significantly decreased between days 1 and 3 in the "hydrocortisone group," whereas there was no significant change in the "reference group". Surprisingly, sICAM-1 levels significantly increased between days 1 and 3 only in patients treated by hydrocortisone. No significant changes were observed for sP-selectin and sVCAM-1 levels in the two groups. In patients with septic shock, glucocorticoids differently affected the pattern of evolution of sCAMs, with sE-selectin being decreased and sICAM-1 being increased. Expression of sP-selectin and sVCAM-1 was not affected.

Publication Types : Clinical Trial Controlled Clinical Trial

PMID : 15179130 [PubMed - indexed for MEDLINE]

17 : Thromb Haemost. 2004 Apr ;91(4):667-73. Related Articles, Links

Comment in : Thromb Haemost. 2004 Apr ;91(4):636-8.

Endothelial microparticles : a potential contribution to the thrombotic complications of the antiphospholipid syndrome.

Dignat-George F, Camoin-Jau L, Sabatier F, Arnoux D, Anfosso F, Bardin N, Veit V, Combes V, Gentile S, Moal V, Sanmarco M, Sampol J.

INSERM EMI 0019 : Physiopathology of the endothelium, UFR de Pharmacie, 27 Bd Jean Moulin, 13385 Marseille Cedex 5, France. dignat

The antiphospholipid syndrome (APS) refers to persistent anti-phospholipid antibodies (aPL) associated with thrombotic and/or obstetrical complications. The endothelial cell is a target of aPL which can induce a procoagulant and proinflammatory endothelial phenotype, as reported both in vivo and in vitro. Microparticle production is a hallmark of cell activation. In the present study, the presence of endothelial microparticles (EMP) in the plasma of APS patients was investigated. To determine if there is a correlation with certain biological and clinical features, EMP levels were measured in thrombosis-free patients with systemic lupus erythematosus (SLE) patients, with and without aPL, in patients with non aPL-related thrombosis, as well as in healthy controls. Compared to healthy subjects, elevated plasma levels of EMP were found in patients with APS and in SLE patients with aPL, but not in SLE patients without aPL or in non aPL-related thrombosis. EMP levels were also associated with Lupus Anticoagulant (LA) detected by a positive Dilute Russell’s Viper Venom time (DRVVT). In parallel, we analyzed the capacity of these plasma to induce vesiculation of cultured endothelial cells. We demonstrated an increase of EMP generated in response to plasma from patients with auto-immune diseases. Interestingly, only APS plasma induced the release of EMP with procoagulant activity. These ex vivo and in vitro observations indicate that generation of EMP in APS and SLE patients results from an autoimmune process involving aPL. Production of procoagulant microparticles in APS patients may represent a new pathogenic mechanism for the thrombotic complications of this disease.

PMID : 15045126 [PubMed - indexed for MEDLINE]

18 : Biochem Biophys Res Commun. 2004 Mar 26 ;316(1):170-6. Related Articles, Links

Homocysteine modulates the proteolytic potential of human vascular endothelial cells.

Chaussalet M, Lamy E, Foucault-Bertaud A, Genovesio C, Sabatier F, Dignat-George F, Charpiot P.

Laboratory of Biochemistry, INSERM U 608, School of Pharmacy, University of the Mediterranean, Marseille, France.

Pathological levels of homocysteine induce a metalloproteinase-dependent degradation of the elastic structures in arterial wall. This elastolytic process is preferentially localized toward the internal elastic laminae and in the first layers of the media, suggesting endothelium could participate in extracellular matrix degradation induced by homocysteine. Therefore, we studied the effects of homocysteine on proteolytic potential of endothelial cells. Human umbilical vein endothelial cells were cultured with concentrations of homocysteine matching human physiological (10 microM) and pathological (50, 100, and 250 microM) plasma homocysteine levels. Pathological levels of homocysteine increased the secretion of elastolytic metalloproteinase-2 and -9, but not of metalloproteinase-3 and -7. Homocysteine also increased the expression of human tissue kallikrein, a potential activator of matrix metalloproteinase-2 and -9, while the expression of urokinase plasminogen activator was not altered. These results suggest vascular endothelial cells could participate in the subendothelial degradation of the arterial elastic structures occurring in hyperhomocysteinemia.

PMID : 15003526 [PubMed - indexed for MEDLINE]

19 : Thromb Haemost. 2003 Nov ;90(5):915-20. Related Articles, Links

Soluble CD146, a novel endothelial marker, is increased in physiopathological settings linked to endothelial junctional alteration.

Bardin N, Moal V, Anfosso F, Daniel L, Brunet P, Sampol J, Dignat George F.

INSERM EMI 0019, Physiopathologie de l’endothelium, Universite de la Mediterranee, UFR Pharmacie, Marseille, France. bardin

CD146, a novel cell adhesion molecule localized at the endothelial junction, is involved in the control of cell-cell cohesion. It is found as a soluble form in conditioned medium of cultured endothelial cells. We developed an ELISA and report for the first time the presence of a soluble form of CD146 (sCD146) in the plasma of healthy subjects. Mean sCD146 values (260 +/- 60 ng/ml) were higher in subjects over 50 years and in men. We therefore investigated sCD146 values in patients with chronic renal failure (CRF), a clinical setting associated with junctional alterations. A significant increase in sCD146 was found in patients with CRF matched with controls (457 +/- 181 ng/ml versus 288 +/- 82 ng/ml respectively, p<0.0001). This increase was corroborated by increased endothelial expression of CD146 on kidney biopsies from patients with CRF. In contrast, in patients with CRF no modulation was observed for the soluble and cell-associated form of CD31, another junctional molecule. Together these data indicate that sCD146 circulates in the plasma of healthy subjects. Modifications of its basal levels could reflect alterations of junctional functions such as vascular permeability.

PMID : 14597988 [PubMed - indexed for MEDLINE]

20 : Pathophysiol Haemost Thromb. 2003 Sep-2004 Dec ;33(5-6):495-9. Related Articles, Links

Circulating endothelial cells : realities and promises in vascular disorders.

Dignat-George F, Sampol J, Lip G, Blann AD.

UMR INSERM 608, Laboratoire d’Hematologie et Immunologie, University of Marseille, France. dignat

Endothelial contribution to human vascular disorders is difficult to investigate, owing to the paucity of non-invasive methods and of specific endothelial markers .Circulating endothelial cells (CECs) might be used asa surrogate non-invasive marker for the study of vascular alterations. To address this problem, we produced an antibody against the endothelial molecule CD126 (S-Endol) and developed, in the nineties, an original and sensitive immunomagnetic separation assay. Using this approach, we demonstrated elevated number of CECs in clinical diseases linked with vascular injury like heart catheterization, sickle cell anemia,bacterial infection, thrombotic thrombocytopenic purpura or acute coronary syndromes. CECs correspond to very rare cells present in blood since levels in the range of 3 cells/ml are detectable in these pathologies.Several clinical interest of CECs will be discussed including their relevance as marker of disease activity, severity or treatment efficacy, or their use in diagnostic tests. The origin of endothelial cells in peripheral blood is difficult to establish. They could correspond to endothelial cells dislodged from the vessels in response to injury. It was subsequently shown that a subset of CECs comprised a population of bone marrow-derived endothelial progenitors that participate in angiogenesis. Identification of the origin and characteristics of CECs provides fascinating insights into endothelial cell pathophysiology. Moreover, CECs constitute original and promising tools for diagnosis, prognosis and therapy of vascular disorders.

Publication Types : Review 21 : Thromb Haemost. 2003 Mar ;89(3):486-92. Related Articles, Links

Circulating microparticles : a marker of procoagulant state in normal pregnancy and pregnancy complicated by preeclampsia or intrauterine growth restriction.

Bretelle F, Sabatier F, Desprez D, Camoin L, Grunebaum L, Combes V, D’Ercole C, Dignat-George F.

Service de Gynecologie-Obstetrique, Pr. B. Blanc, Centre Hospitalo’Universitaire de la Conception, Marseille, France.

In the present study, we explored the microparticles involved in the control of hemostatic equilibrium, i.e microparticles originating from platelet, endothelial cells and total MP defined as annexin V positive microparticles. Our aim was to analyze the level and procoagulant activity of these microparticles in normal pregnancy and pregnancies complicated with preeclampsia or isolated intrauterine growth restriction. We reported increased levels of platelet and endothelial microparticles in normal pregnancy compared to non pregnant healthy women. Number of annexin V microparticles was significantly increased together with their procoagulant activity. In pathological pregnancies, significant reduction in platelet microparticle number was found in preeclampsia. The procoagulant activity generated by the total annexin V MP was unchanged, suggesting that the microparticles remaining in the circulation were procoagulant. This study evidenced that microparticles constitute a cellular marker of a proinflammatory and procoagulant responses in normal pregnancy. In pregnancies with vascular complications, circulating MP with procoagulant potential may be part of the exacerbation of these responses.

PMID : 12624632 [PubMed - indexed for MEDLINE]

22 : Haematologica. 2002 Nov ;87(11):ECR35. Related Articles, Links

A CD4+ V(beta)13.6+ CD56+ large granular lymphocyte expansion with decreased expression of CD95 and an indolent clinical course.

Schleinitz N, Brunet C, Pascal V, Potie C, Veit V, Paul P, Dignat-George F, Harle JR.

Service de Medecine Interne, Hopital de la Conception, Marseille, France. nschleinitz

Publication Types : Case Reports

PMID : 12414361 [PubMed - indexed for MEDLINE]

23 : Leukemia. 2002 Nov ;16(11):2259-66. Related Articles, Links

Analysis of donor NK and T cells infused in patients undergoing MHC-matched allogeneic hematopoietic transplantation.

Pascal V, Brunet C, Pradel V, Thirion X, Andre P, Faucher C, Sampol J, Dignat-George F, Blaise D, Vivier E, Chabannon C.

Centre d’Immunologie INSERM/CNRS de Marseille-Luminy, France.

We retrospectively analyzed the percentages and absolute numbers of T cells, natural killer (NK) cells and NK cell subsets in cryopreserved samples of either bone marrow or blood non-T cell-depleted allogeneic MHC-matched hematopoietic grafts. Using flow cytometry, we found higher numbers of NK cells in aphereses than in bone marrow collections. We further investigated the distribution of NK cell subsets, defined by the cell surface expression of MHC class I-specific receptors, in these allogeneic grafts. The distribution of NK cell subsets from the two different origins were similar, with the exception of the CD158a/h(+) NK cell subset, whose size appeared to be smaller in bone marrow. The search for relations between the numbers of infused cells and post-transplantation events demonstrated that increasing numbers of infused T cells but not NK cells are related with decreased overall survival. Our study highlights the toxicity of infused T cells but not NK cells in allogeneic MHC-matched hematopoietic grafts. These data pave the way for further trials to investigate the effect of NK cell infusion in MHC-matched allogeneic transplantation, and in particular whether ex vivo NK cell expansion and activation may enhance the anti-tumoral effect of the procedure and decrease its morbidity.

PMID : 12399971 [PubMed - indexed for MEDLINE]

24 : Diabetes. 2002 Sep ;51(9):2840-5. Related Articles, Links

Type 1 and type 2 diabetic patients display different patterns of cellular microparticles.

Sabatier F, Darmon P, Hugel B, Combes V, Sanmarco M, Velut JG, Arnoux D, Charpiot P, Freyssinet JM, Oliver C, Sampol J, Dignat-George F.

INSERM EMI 0019, Laboratory of Immunology and Hematology, UFR de Pharmacie, Universite de la Mediterranee, Marseille, France.

The development of vasculopathies in diabetes involves multifactorial processes including pathological activation of vascular cells. Release of microparticles by activated cells has been reported in diseases associated with thrombotic risk, but few data are available in diabetes. The aim of the present work was to explore the number and the procoagulant activity of cell-derived microparticles in type 1 and 2 diabetic patients. Compared with age-matched control subjects, type 1 diabetic patients presented significantly higher numbers of platelet and endothelial microparticles (PMP and EMP), total annexin V-positive blood cell microparticles (TMP), and increased levels of TMP-associated procoagulant activity. In type 2 diabetic patients, only TMP levels were significantly higher without concomitant increase of their procoagulant activity. Interestingly, in type 1 diabetic patients, TMP procoagulant activity was correlated with HbA(1c), suggesting that procoagulant activity is associated with glucose imbalance. These results showed that a wide vesiculation process, resulting from activation or apoptosis of several cell types, occurs in diabetes. However, diabetic patients differ by the procoagulant activity and the cellular origin of microparticles. In type 1 diabetic patients, TMP-procoagulant activity could be involved in vascular complications. Moreover, its correlation with HbA(1c) reinforces the importance of an optimal glycemic control in type 1 diabetes.

PMID : 12196479 [PubMed - indexed for MEDLINE]

25 : Thromb Haemost. 2002 Sep ;88(3):517-23. Related Articles, Links

Platelet associated u-PA up-regulates u-PA synthesis by endothelial cells.

Camoin-Jau L, Pannell R, Anfosso F, Bardin N, Sabatier F, Sampol J, Gurewich V, Dignat-George F.

INSERM EMI 00-19, Laboratoire d’Hematologie, Univ Mediterranee, UFR de Pharmacie and Hjpital de la Conception, Marseille, France.

Adhesion of platelets to endothelium has been shown to induce important changes in endothelial properties. In this study, we examined the effect of platelet-endothelial cell interactions on the expression of urokinase-type plasminogen activator (u-PA) by human microvascular endothelial cells. After incubation of endothelial cells with platelets, a dose-dependent increase in the expression of u-PA Ag was observed and reached a plateau for a ratio of 300 platelets per endothelial cells. The u-PA Ag upregulation resulted from an increase in u-PA mRNA that originated from a synthesis by endothelial cells since no u-PA mRNA was detected in platelets. The platelet-induced u-PA synthesis was inhibited when the endothelial cells were pre-treated with phospholipase C to remove the u-PA receptor, or when the platelets were incubated with an antibody that blocks the binding of u-PA to u-PAR. Taken together, these data indicate that u-PA present on the platelet surface interacts with u-PAR on the endothelial cells and induces the u-PA synthesis. This mechanism may represent a physiological control of platelet-mediated intravascular fibrin deposition.

PMID : 12353084 [PubMed - indexed for MEDLINE]

26 : Blood. 2002 Jun 1 ;99(11):3962-70. Related Articles, Links

Interaction of endothelial microparticles with monocytic cells in vitro induces tissue factor-dependent procoagulant activity.

Sabatier F, Roux V, Anfosso F, Camoin L, Sampol J, Dignat-George F.

INSERM EMI 00-19, Laboratoire d’Hematologie et d’Immunologie, UFR de Pharmacie, Universite de la Mediterranee, Marseilles, France.

In the present study we investigated whether endothelial microparticles (EMPs) can bind to monocytic THP-1 cells and modulate their procoagulant properties. Using flow cytometry, we demonstrated that EMPs express adhesive receptors similar to those expressed by activated endothelial cells. Expression of endothelial antigens by THP-1 cells incubated with EMP was shown by immunoperoxidase staining and flow cytometry using antibodies directed against E-selectin, VCAM-1, and endoglin. EMP binding to THP-1 cells was time- and concentration- dependent, reached a plateau at 15 minutes, and had an EMP-to-monocyte ratio of 50:1. EMP binding was not affected by low temperature and was not followed by the restoration of phosphatidylserine asymmetry, suggesting that adhesion was not followed by fusion. A 4-hour incubation of THP-1 cells with EMP led to an increase in procoagulant activity as measured by clotting assay. Concomitantly, THP-1 exhibited increased levels of tissue factor (TF) antigen and TF mRNA compared to control cells. The ability of EMP to induce THP-1 procoagulant activity was significantly reduced when THP-1 cells were incubated with EMP in the presence of blocking antibodies against ICAM-1 and beta2 integrins. These results demonstrate that EMPs interact with THP-1 cells in vitro and stimulate TF-mediated procoagulant activity that is partially dependent on the interaction of ICAM-1 on EMP and its counterreceptor, beta2 integrins, on THP-1 cells. Induction of procoagulant activity was also demonstrated using human monocytes, suggesting a novel mechanism by which EMP may participate in the dissemination and amplification of procoagulant cellular responses.

PMID : 12010795 [PubMed - indexed for MEDLINE]

27 : Crit Care Med. 2002 Apr ;30(4):808-14. Related Articles, Links

Systemic endothelial activation is greater in septic than in traumatic-hemorrhagic shock but does not correlate with endothelial activation in skin biopsies.

Leone M, Boutiere B, Camoin-Jau L, Albanese J, Horschowsky N, Mege JL, Martin C, Dignat-George F.

Intensive Care Unit and Trauma Center, Unite des Rickettsies, CNRS UMR 6020, France.

OBJECTIVE : Sepsis and severe trauma result in endothelial activation and damage. The activated endothelium expresses adhesion receptors that control leukocyte trafficking. After activation, some adhesion molecules are also released into plasma as soluble forms. The present study was designed to compare the expression of soluble cell adhesion molecules (sCAMs) in three groups of patients : those with septic shock, severe sepsis, and traumatic-hemorrhagic shock. In addition, the endothelial expression of these adhesive molecules was examined in skin biopsies. DESIGN : Prospective observational study SETTING : Intensive care unit at a university hospital PATIENTS : The study included 15 patients with septic shock (by Bone’s definition), 11 patients with severe sepsis (by Bone’s definition), and 13 patients with traumatic-hemorrhagic shock. Fifteen healthy blood donors served as controls. MEASUREMENTS AND MAIN RESULTS : Measurements of sCAMs were performed on days 1, 2, and 3 of the disease. On day 1, when compared with controls, sE-selectin, sP-selectin, soluble vascular cell adhesion molecule (sVCAM)-1, and soluble intercellular adhesion molecule (sICAM)-1 were markedly elevated in septic shock patients, whereas these sCAMs, except for sP-selectin, were within normal ranges in traumatic-hemorrhagic shock patients. In patients with severe sepsis, an earlier stage than septic shock in the sepsis continuum, intermediate values of sCAMs were found. In skin biopsies of septic shock patients, the endothelial cells expressed a bright staining of constitutive endothelial molecules (CD146, CD144, CD131). Inducible molecules (ICAM-1, VCAM-1, and E-selectin) were positively expressed with bright staining. The biopsies from traumatic-hemorrhagic shock patients showed a similar positive expression of endothelial molecules. CONCLUSION : The patterns of sCAMs indicate that the systemic activation of the endothelium is different in the three clinical entities, maximum in septic shock, intermediate in severe sepsis, and not different from controls in traumatic-hemorrhagic shock. Comparable endothelial activation as evidenced by skin biopsies suggests that caution is required in the interpretation of CAMs in plasma, which does not necessarily reflect the in situ activation state of endothelium.

PMID : 11940750 [PubMed - indexed for MEDLINE]

28 : Hematol J. 2002 ;3(4):216-8. Related Articles, Links Immune reconstitution during intensive chemotherapy in patients with human immunodeficiency virus related non-Hodgkin lymphoma.

Costello RT, Brunet C, Dignat-George F, Sampol J, Olive D, Gastaut JA.

Publication Types : Letter

PMID : 12189569 [PubMed - indexed for MEDLINE]

29 : Blood. 2001 Dec 15 ;98(13):3677-84. Related Articles, Links

Identification of CD146 as a component of the endothelial junction involved in the control of cell-cell cohesion.

Bardin N, Anfosso F, Masse JM, Cramer E, Sabatier F, Le Bivic A, Sampol J, Dignat-George F.

INSERM EMI 0019, Physiopathologie de l’Endothelium, Universite de la Mediterranee, UFR Pharmacie, Marseille, France.

CD146 is a cell-surface molecule belonging to the immunoglobulin superfamily and expressed in all types of human endothelial cells. Confocal and electron microscopic analysis of confluent human umbilical vein endothelial cells (HUVECs) were used to demonstrate that CD146 is a component of the endothelial junction. Double immunolabeling with vascular endothelial cadherin showed that CD146 is localized outside the adherens junction. Moreover, CD146 expression is not restricted to the junction, since part of the labeling was detectable at the apical side of the HUVECs. Interestingly, cell-surface expression of CD146 increased when HUVECs reached confluence. In addition, the paracellular permeability of CD146-transfected fibroblast cells was decreased compared with that of control cells. Finally, CD146 colocalized with actin, was partly resistant to Triton X-100 extraction, and had its expression altered by actin-disrupting agents, indicating that CD146 is associated with the actin cytoskeleton. These results show the regulated expression of CD146 at areas of cell-cell junction and strongly suggest involvement of CD146 as a mediator of cell-cell interaction.

PMID : 11739172 [PubMed - indexed for MEDLINE]

30 : BJOG. 2001 Dec ;108(12):1277-82. Related Articles, Links Maternal endothelial soluble cell adhesion molecules with isolated small for gestational age fetuses : comparison with pre-eclampsia.

Bretelle F, Sabatier F, Blann A, D’Ercole C, Boutiere B, Mutin M, Boubli L, Sampol J, Dignat-George F.

Department of Obstetrics and Gynaecology, Centre Hospitalo-Universitaire de la Conception, Marseille, France.

OBJECTIVE : 1. To evaluate the activation profile of the endothelium in pregnancies complicated by small for gestational age fetuses compared with pre-eclampsia and normal pregnancy, by measuring the plasma levels of soluble adhesion molecules soluble E-selectin, intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1. 2. To determine whether soluble adhesion molecules were related to the severity of small for gestational age fetuses and pre-eclampsia. DESIGN : Observational study. PARTICIPANTS : Sixteen women with small for gestational age fetuses ; 15 women with pre-eclampsia and 15 healthy primigravidae were recruited as controls. METHODS : Plasma levels of soluble E-selectin, intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1 were measured by ELISA. RESULTS : Compared with the healthy controls, soluble E-selectin was significantly increased in both small for gestational age fetuses and pre-eclampsia, whereas intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1 were increased only in pre-eclampsia. In the small for gestational age fetuses group, soluble E-selectin correlated inversely with the ratio between birthweight and the expected normal birthweight (r = -0.4, P = 0.007). In the pre-eclampsia group, a significant correlation was observed between vascular cell adhesion molecule-1 and blood pressure (r = 0.54, P = 0.039). CONCLUSIONS : Endothelial activation, reflected by raised levels of soluble E-selectin, is a feature of small for gestational age fetuses and is correlated with the severity of the disease. Differences in the profile of soluble cell adhesion molecules suggest variations in the degrees of endothelial activation between pre-eclampsia and small for gestational age fetuses.

Publication Types : Case Reports

PMID : 11843391 [PubMed - indexed for MEDLINE]

31 : J Biol Chem. 2001 Jan 12 ;276(2):1564-9. Related Articles, Links

Outside-in signaling pathway linked to CD146 engagement in human endothelial cells.

Anfosso F, Bardin N, Vivier E, Sabatier F, Sampol J, Dignat-George F.

INSERM EMI 00-19 Physiopathologie de l’Endothelium, UFR Pharmacie, Universite de la Mediterranee, 13385 Marseille, France. anfosso

CD146 (S-Endo 1 Ag or MUC18) is a transmembrane glycoprotein expressed on endothelial cells on the whole vascular tree. CD146 is located at the intercellular junction where it plays a role in the cohesion of the endothelial monolayer. CD146 engagement initiates an outside-in signaling pathway involving the protein tyrosine kinases FYN and FAK as well as paxillin. Here we report that CD146 engagement by its specific monoclonal antibody in human umbilical vein endothelial cells induces a Ca(2+) influx that is sensitive to thapsigargin and EGTA treatment, indicating that CD146 engagement initiates a store-operated calcium mobilization. In addition, biochemical and pharmacological analysis revealed that CD146 engagement initiates the tyrosine phosphorylation of phospholipase C-gamma, Pyk2, and p130(Cas). Pharmacological inhibition of Ca(2+) flux with 1,2-bis(o-aminophenoxy)ethane-N,N,N’,N’-tetraacetic acetoxymethyl ester and EGTA indicated that an increase in Ca(2+) is required for Pyk2 and p130(Cas) tyrosine phosphorylation. Moreover, a complex association was observed between Pyk2, p130(Cas), and paxillin. These results indicate that CD146 is coupled to a FYN-dependent pathway that triggers Ca(2+) flux via phospholipase C-gamma activation leading subsequently to the tyrosine phosphorylation of downstream targets such as Pyk2, p130(Cas), FAK, and paxillin. In addition to its role in cell-cell adhesion, CD146 is a signaling molecule involved in the dynamics of actin cytoskeleton rearrangement.

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