scholarly journals Molecular and cellular properties of PECAM-1 (endoCAM/CD31): a novel vascular cell-cell adhesion molecule.

1991 ◽  
Vol 114 (5) ◽  
pp. 1059-1068 ◽  
Author(s):  
S M Albelda ◽  
W A Muller ◽  
C A Buck ◽  
P J Newman

PECAM-1 is a 130-120-kD integral membrane glycoprotein found on the surface of platelets, at endothelial intercellular junctions in culture, and on cells of myeloid lineage. Previous studies have shown that it is a member of the immunoglobulin gene superfamily and that antibodies against the bovine form of this protein (endoCAM) can inhibit endothelial cell-cell interactions. These data suggest that PECAM-1 may function as a vascular cell adhesion molecule. The function of this molecule has been further evaluated by transfecting cells with a full-length PECAM-1 cDNA. Transfected COS-7, mouse 3T3 and L cells expressed a 130-120-kD glycoprotein on their cell surface that reacted with anti-PECAM-1 polyclonal and monoclonal antibodies. COS-7 and 3T3 cell transfectants formed cell-cell junctions that were highly enriched in PECAM-1, reminiscent of its distribution at endothelial cell-cell borders. In contrast, this protein remained diffusely distributed within the plasma membrane of PECAM-1 transfected cells that were in contact with mock transfectants. Mouse L cells stably transfected with PECAM-1 demonstrated calcium-dependent aggregation that was inhibited by anti-PECAM antibodies. These results demonstrate that PECAM-1 mediates cell-cell adhesion and support the idea that it may be involved in some of the interactive events taking place during thrombosis, wound healing, and angiogenesis.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3691-3691
Author(s):  
Solomon F. Ofori-Acquah

Abstract Activated leukocyte cell adhesion molecule (ALCAM/CD166) is a member of the immunoglobulin cell adhesion super family, which has been implicated in diverse physiological and pathophysiological events involving cell migration. Hitherto, ALCAM’s role in inflammation has not been determined. In this study, we show ALCAM is involved in controlling migration of mononuclear leukocytes across the pulmonary endothelium. We demonstrated that ALCAM is localized at intercellular junctions in pulmonary microvascular endothelial cells in vitro and in vivo. ALCAM co-localized with multiple adherens junction molecules including cadherins, catenins and Dlg, as determined by confocal microscopy, and these observations were confirmed by co-immunoprecipitation and co-distribution assays. Treatment of endothelial cultures with EGTA and cytochalasin D translocated ALCAM from intercellular junctions to the cytosol indicating a requirement for homotypic cadherin adhesion and an intact endothelial cytoskeleton for maintaining ALCAM at endothelial cell junctions. Collectively, these data supports the conclusion that ALCAM contributes to the adherens junction complex in endothelial cells. To determine ALCAM’s role in leukocyte-endothelial cell interactions, adult Sprague Dawley rats were intratracheally instilled with macrophage inflammatory protein-1, and this treatment caused acute expression of ALCAM exclusively in newly recruited mononuclear but not polymorphonuclear leukocytes in the alveolar airway. Given that no ALCAM reactivity was observed in peripheral blood leukocytes, we concluded ALCAM is activated as part of the phenotypic switch by mononuclear leukocytes transitioning from circulation to interstitial tissue compartments. To determine the physiological relevance of this finding we examined whether ALCAM was required for transendothelial migration using monocyte chemoattractant protein 1 (MCP-1). MCP-1 dose- and time-dependently increased the number of transmigrated THP-1 monocytes across pulmonary microvascular endothelial monolayers. Recombinant soluble ALCAM dose-dependently reduced the number of transmigrated THP-1 monocytes, whereas in control experiments recombinant soluble vascular endothelial cadherin had no effect on transmigration. This study shows for the first time that ALCAM is located at endothelial cell junctions where it is intimately involved in controlling the number of monocytes that pass through endothelial barriers. ALCAM may therefore play an essential role in the response to inflammation by enhancing recruitment of mononuclear leukocytes by inflamed tissues.


1995 ◽  
Vol 60 (11) ◽  
pp. 1299-1305 ◽  
Author(s):  
JOHN P. MUELLER ◽  
MARK J. EVANS ◽  
ROXANNE COFIELL ◽  
RUSSELL P. ROTHER ◽  
LOUIS A. MATIS ◽  
...  

1997 ◽  
Vol 8 (7) ◽  
pp. 1329-1341 ◽  
Author(s):  
N Sheibani ◽  
P J Newman ◽  
W A Frazier

Expression of thrombospondin-1 (TS1) in polyoma middle-sized T (tumor)-transformed mouse brain endothelial cells (bEND.3) restores a normal phenotype and suppresses their ability to form hemangiomas in mice. We show that TS1 expression results in complete suppression of platelet-endothelial cell adhesion molecule-1 (PECAM-1) expression and altered cell-cell interactions in bEND.3 cells. To further investigate the role of PECAM-1 in regulation of endothelial cell-cell interactions and morphogenesis, we expressed human (full length) or murine (delta 15) PECAM-1 isoforms in TS1-transfected bEND.3 (bEND/TS) cells. Expression of either human or murine PECAM-1 resulted in an enhanced ability to organize and form networks of cords on Matrigel, an effect that was specifically blocked by antibodies to PECAM-1. Anti-PECAM-1 antibodies also inhibited tube formation in Matrigel by normal human umbilical vein endothelial cells. However, PECAM-1-transfected bEND/TS cells did not regain the ability to form hemangiomas in mice and the expressed PECAM-1, unlike the endogenous PECAM-1 expressed in bEND.3 cells, failed to localize to sites of cell-cell contact. This may be, in part, attributed to the different isoforms of PECAM-1 expressed in bEND.3 cells. Using reverse transcription-polymerase chain reaction, we determined that bEND.3 cells express mRNA encoding six different PECAM-1 isoforms, the isoform lacking both exons 14 and 15 (delta 14&15) being most abundant. Expression of the murine delta 14&15 PECAM-1 isoform in bEND/TS cells resulted in a similar phenotype to that described for the full-length human or murine delta 15 PECAM-1 isoform. The delta 14&15 isoform, despite the lack of exon 14, failed to localize to sites of cell-cell contact even in clones that expressed it at very high levels. Thus, contrary to recent reports, lack of exon 14 is not sufficient to result in junctional localization of PECAM-1 isoforms in bEND/TS cells.


1997 ◽  
Vol 139 (1) ◽  
pp. 219-228 ◽  
Author(s):  
Marek Litwin ◽  
Katherine Clark ◽  
Leanne Noack ◽  
Jill Furze ◽  
Michael Berndt ◽  
...  

Tumor necrosis factor–α, interleukin-1, and endotoxin stimulate the expression of vascular endothelial cell (EC) adhesion molecules. Here we describe a novel pathway of adhesion molecule induction that is independent of exogenous factors, but which is dependent on integrin signaling and cell–cell interactions. Cells plated onto gelatin, fibronectin, collagen or fibrinogen, or anti-integrin antibodies, expressed increased amounts of E-selectin, vascular cell adhesion molecule–1, and intercellular adhesion molecule–1. In contrast, ECs failed to express E-selectin when plated on poly-l-lysine or when plated on fibrinogen in the presence of attachment-inhibiting, cyclic Arg-Gly-Asp peptides. The duration and magnitude of adhesion molecule expression was dependent on EC density. Induction of E-selectin on ECs plated at confluent density was transient and returned to basal levels by 15 h after plating when only 7 ± 2% (n = 5) of cells were positive. In contrast, cells plated at low density displayed a 17-fold greater expression of E-selectin than did high density ECs with 57 ± 4% (n = 5) positive for E-selectin expression 15 h after plating, and significant expression still evident 72 h after plating. The confluency-dependent inhibition of expression of E-selectin was at least partly mediated through the cell junctional protein, platelet/endothelial cell adhesion molecule–1 (PECAM-1). Antibodies against PECAM-1, but not against VE-cadherin, increased E-selectin expression on confluent ECs. Co– culture of subconfluent ECs with PECAM-1– coated beads or with L cells transfected with full-length PECAM-1 or with a cytoplasmic truncation PECAM-1 mutant, inhibited E-selectin expression. In contrast, untransfected L cells or L cells transfected with an adhesion-defective domain 2 deletion PECAM-1 mutant failed to regulate E-selectin expression. In an in vitro model of wounding the wound front displayed an increase in the number of E-selectin–expressing cells, and also an increase in the intensity of expression of E-selectin positive cells compared to the nonwounded monolayer. Thus we propose that the EC junction, and in particular, the junctional molecule PECAM-1, is a powerful regulator of endothelial adhesiveness.


1995 ◽  
Vol 60 (11) ◽  
pp. 1299-1305 ◽  
Author(s):  
JOHN P. MUELLER ◽  
MARK J. EVANS ◽  
ROXANNE COFIELL ◽  
RUSSELL P. ROTHER ◽  
LOUIS A. MATIS ◽  
...  

1999 ◽  
Vol 144 (2) ◽  
pp. 325-337 ◽  
Author(s):  
Farzad Esni ◽  
Inge-Bert Täljedal ◽  
Anne-Karina Perl ◽  
Harold Cremer ◽  
Gerhard Christofori ◽  
...  

Classical cell dissociation/reaggregation experiments with embryonic tissue and cultured cells have established that cellular cohesiveness, mediated by cell adhesion molecules, is important in determining the organization of cells within tissue and organs. We have employed N-CAM-deficient mice to determine whether N-CAM plays a functional role in the proper segregation of cells during the development of islets of Langerhans. In N-CAM-deficient mice the normal localization of glucagon-producing α cells in the periphery of pancreatic islets is lost, resulting in a more randomized cell distribution. In contrast to the expected reduction of cell–cell adhesion in N-CAM-deficient mice, a significant increase in the clustering of cadherins, F-actin, and cell–cell junctions is observed suggesting enhanced cadherin-mediated adhesion in the absence of proper N-CAM function. These data together with the polarized distribution of islet cell nuclei and Na+/K+-ATPase indicate that islet cell polarity is also affected. Finally, degranulation of β cells suggests that N-CAM is required for normal turnover of insulin-containing secretory granules. Taken together, our results confirm in vivo the hypothesis that a cell adhesion molecule, in this case N-CAM, is required for cell type segregation during organogenesis. Possible mechanisms underlying this phenomenon may include changes in cadherin-mediated adhesion and cell polarity.


1998 ◽  
Vol 142 (5) ◽  
pp. 1381-1391 ◽  
Author(s):  
P. Lorenzon ◽  
E. Vecile ◽  
E. Nardon ◽  
E. Ferrero ◽  
J.M. Harlan ◽  
...  

Previous studies have shown that polymorphonuclear leukocyte (PMN) adherence to endothelial cells (EC) induces transient increases in EC cytosolic free calcium concentration ([Ca2+]i) that are required for PMN transit across the EC barrier (Huang, A.J., J.E. Manning, T.M. Bandak, M.C. Ratau, K.R. Hanser, and S.C. Silverstein. 1993. J. Cell Biol. 120:1371–1380). To determine whether stimulation of [Ca2+]i changes in EC by leukocytes was induced by the same molecules that mediate leukocyte adherence to EC, [Ca2+]i was measured in Fura2-loaded human EC monolayers. Expression of adhesion molecules by EC was induced by a pretreatment of the cells with histamine or with Escherichia coli lipopolysaccharide (LPS), and [Ca2+]i was measured in single EC after the addition of mAbs directed against the EC adhesion proteins P-selectin, E-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), or platelet/endothelial cell adhesion molecule-1 (PECAM-1). Both anti–P- and anti–E-selectin mAb, as well as anti–VCAM-1 mAb, induced transient increases in EC [Ca2+]i that were comparable to those induced by 200 μM histamine. In contrast, no effect was obtained by mAbs directed against the endothelial ICAM-1 or PECAM-1. PMN adherence directly stimulated increases in [Ca2+]i in histamine- or LPS-treated EC. mAbs directed against leukocyte CD18 or PECAM-1, the leukocyte counter-receptors for endothelial ICAM-1 and PECAM-1, respectively, did not inhibit PMN-induced EC activation. In contrast, mAb directed against sialyl Lewis x (sLex), a PMN ligand for endothelial P- and E-selectin, completely inhibited EC stimulation by adherent PMN. Changes in EC [Ca2+]i were also observed after adherence of peripheral blood monocytes to EC treated with LPS for 5 or 24 h. In these experiments, the combined addition of mAbs to sLex and VLA-4, the leukocyte counter-receptor for endothelial VCAM-1, inhibited [Ca2+]i changes in the 5 h–treated EC, whereas the anti–VLA-4 mAb alone was sufficient to inhibit [Ca2+]i changes in the 24 h-treated EC. Again, no inhibitory effect was observed with an anti-CD18 or anti–PECAM-1 mAb. Of note, the conditions that induced changes in EC [Ca2+]i, i.e., mAbs directed against endothelial selectins or VCAM-1, and PMN or monocyte adhesion to EC via selectins or VCAM-1, but not via ICAM-1 or PECAM-1, also induced a rearrangement of EC cytoskeletal microfilaments from a circumferential ring to stress fibers. We conclude that, in addition to their role as adhesion receptors, endothelial selectins and VCAM-1 mediate endothelial stimulation by adhering leukocytes.


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