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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently we described the isolation of a mouse cDNA clone encoding a mucin-like endothelial glycoprotein that appears to function as an adhesive ligand for L selectin. This ligand has been named GlyCAM 1 (Gly-cosylation-dependent Cell Adhesion Molecule 1) because its adhesive interactions with the L selectin lectin domain require that the GlyCAM 1 polypeptide chain be appropriately modified with carbohydrates. These carbohydrate modifications include the addition of sialic acid as well as sulfate residues to O-linked carbohydrate side chains that are clustered in two serine/threonine-rich domains of the mucin. An additional interesting structure that may have relevance to the association of GlyCAM 1 with the lumenal surface of the endothelium was a potential amphipathic helix at the C terminus of the glycoprotein. In order to examine the importance of the postulated O-linked domains as well as the potential amphipathic helix, we have cloned the rat homologue of GlyCAM 1. The sequence of this clone reveals a serine/threonine-rich protein that is highly homologous with the mouse GlyCAM 1. As was found for the mouse GlyCAM 1, the rat homologue shows a clustering of these potential O-linked carbohydrate acceptors in two domains of the protein. Interestingly, many of the serines and threonines are found to be spaced identically in the two homologues, consistent with the possibility that both density and position of the O-linked side chains may be important for appropriate L selectin-mediated adhesion. In support of its postulated functional importance, the C-terminal potential amphipathic helix is conserved in the rat homologue. Finally, immunoprecipitation analysis of [35S]sulfate-labeled rat lymph nodes with either a mouse L selectin IgG chimera or a peptide antiserum directed against a relatively conserved portion of mouse GlyCAM 1 demonstrates a approximately 45-kDa sulfated ligand in rat lymph nodes that is analogous to that previously described for mouse lymph nodes.
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PMID:Cloning of a rat homologue of mouse GlyCAM 1 reveals conservation of structural domains. 810 Feb 29

Human umbilical vein endothelial cells (HUVEC) were used as an experimental host model to investigate the mechanism(s) of streptococcal adhesion in infective endocarditis. Adhesion activity of Streptococcus gordonii was maximal during the logarithmic phase of growth and was greatly reduced or eliminated by pretreatment of bacteria with heat, formaldehyde, or trypsin. At saturating numbers of streptococci, an average of 81 bacteria were bound per HUVEC. Streptococcal adhesion was inhibited by low-molecular-weight dextran and heparin but not by sucrose, fibronectin, or laminin. Adhesion was also prevented by pretreatment of HUVEC with proteins dissociated from the surface of S. gordonii with 10 mM EDTA or isolated from spent culture medium. Western blot (immunoblot) assays detected a single adhesion protein of 153 kDa (AP153) on HUVEC after incubation with unfractionated extracts of streptococci. The adhesin exhibited glucosyltransferase (GTF) activity when incubated with sucrose and Triton X-100 after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The AP153 was purified by affinity chromatography on dextran beads and show to have binding activity for HUVEC, GTF activity, an amino acid composition similar to that reported for GTF of S. gordonii, and the ability to inhibit S. gordonii adhesion. Incubation of the streptococci with antibodies to the adhesin inhibited bacterial attachment to HUVEC monolayers. These results indicate that surface-localized GTF mediates adhesion of S. gordonii to HUVEC in vitro and may serve as a mechanism for colonization of the endocardium in infective endocarditis.
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PMID:Glucosyltransferase mediates adhesion of Streptococcus gordonii to human endothelial cells in vitro. 818 39

The mechanisms responsible for the accumulation of eosinophils at sites of allergic and other inflammatory reactions are unknown, but recent studies have implicated both eosinophil and endothelial adhesion molecules in this process. However, less well studied have been the adhesive interactions between eosinophils and the subendothelial basement membrane and interstitial connective tissues. To test the hypothesis that eosinophils might interact with extracellular matrix proteins, we analyzed purified human eosinophils for the expression and function of various beta 1 integrins. Using indirect immunofluorescence and flow cytometry, purified eosinophils from mildly allergic donors were found to consistently express the integrin subunits beta 1 (CD29), alpha 4 (CD49d, very late activation antigen [VLA]-4 alpha), and alpha 6 (CD49f, VLA-6 alpha). No significant expression of the alpha 1, alpha 2, alpha 3, alpha 5, or beta 4 subunits was detected. Platelet contamination of the eosinophil preparations was excluded by light microscopy and by the inability to detect expression of platelet glycoproteins alpha v, CD41b, and CD42b. Immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of eosinophils confirmed the expression of cell-surface beta 1, alpha 4, and alpha 6. Furthermore, eosinophils purified from allergic donors were shown to adhere to plate-bound laminin, but not to type 1 or type 4 collagen. Adhesion to laminin was concentration-dependent, required divalent cations, and was completely and specifically inhibited by the anti-alpha 6 monoclonal antibody (MoAb) GoH3 and by the anti-beta 1 MoAb 33B6. Interestingly, the anti-beta 1 MoAb 18D3 (which like 33B6 blocks eosinophil binding to VCAM-1) did not inhibit eosinophil adhesion to laminin, suggesting that there are functionally distinct epitopes on the beta 1 subunit. Eosinophils purified from 4 healthy, nonallergic donors also showed alpha 6-dependent adhesion to laminin, although these cells adhered less well. These studies establish the expression of alpha 6 beta 1 on human eosinophils and document its function as a laminin receptor. Interaction of eosinophil alpha 6 beta 1 with laminin, eg, in basement membranes, may contribute to the localization of these cells at inflammatory sites in vivo.
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PMID:Expression of a functional laminin receptor (alpha 6 beta 1, very late activation antigen-6) on human eosinophils. 821 35

A heparin-binding glycoprotein was purified from conditioned medium of cultured rat Schwann cells. The protein, p200, which has an apparent molecular mass of approximately 200 kDa, was identified by its ability to bind the cell surface heparan sulfate proteoglycan N-syndecan (syndecan-3) in a membrane overlay assay. Soluble heparin but not chondroitin sulfate inhibited the binding, suggesting the involvement of heparan sulfate chains of proteoglycan in the interaction. Purified p200 promoted the attachment and spreading of Schwann cells. Adhesion to p200 was blocked by heparin, suggesting that heparan sulfate proteoglycans are cell surface receptors for p200. The tissue distribution of p200 was determined by immunoblot analysis with anti-p200 antibodies. Among neonatal rat tissues examined p200 was detected only in sciatic nerve and, at lower levels, in skeletal muscle. p200 expression in sciatic nerve was detectable only during the first 2-3 weeks of postnatal development and was not detected in adult rats. Immunofluorescent staining of rat sciatic nerve showed that p200 was localized in the extracellular matrix surrounding individual Schwann cells-axon units. Two tryptic peptides from p200 were purified and sequenced. These contained multiple GXX collagen-like repeats. Bacterial collagenase digestion of p200 produced a product with an apparent molecular mass of approximately 90 kDa. These data suggest that Schwann cells secrete an apparently novel collagen-like adhesive protein that interacts with cells through cell surface heparan sulfate proteoglycans.
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PMID:Schwann cells secrete a novel collagen-like adhesive protein that binds N-syndecan. 866 84

Cell surface-expressed proteoglycans mediate contacts to extracellular matrix (ECM). Human B lymphocytes produce a species of a proteochondroitin sulfate (CSPG) with an approximate molecular mass of 135-150 kDa. Using a monoclonal antibody (mAb) against B cell CSPG in flow cytometry we found that this CSPG is expressed on tumor cells of patients with CD19+ common acute lymphoblastic leukemia and on the corresponding cell lines Nalm-6, Reh and KM3. The CSPG is also present on hairy cell leukemia JOK-1 cells and weakly on the myeloma line U266. Concomitant with CSPG expression, Nalm-6 cells express the integrins alpha 5/beta 1 (CD49e/CD29) and alpha 6/beta 1 (CD49f/CD29), adhesion receptors for fibronectin and laminin, in contrast to the other two cell lines tested. Expression patterns of these adhesion receptors and CSPG were paralleled by strong adhesion of Nalm-6 to fibronectin and laminin. Adhesion of Nalm-6 to fibronectin was inhibited by the alpha 5-specific antibody SAM 1 by 80% whereas the alpha 6-specific antibody GoH3 reduced binding to laminin only by 20%. A possible involvement of surface-expressed CSPG in adhesion to ECM components was investigated by 24 h incubation of Nalm-6 cells with p-nitrophenyl-beta-D-xyloside, an inhibitor of proteoglycan glycosylation. By this treatment, both adhesion of Nalm-6 to laminin and expression of CSPG were reduced by 40-50%. Furthermore, addition of chondroitin-6-sulfate, a structural element of Nalm-6 CSPG, reduced adhesion of Nalm-6 to laminin by 60%. Chondroitin-4-sulfate, heparin and heparan sulfate did not effectively inhibit the adhesion process. These observations suggest that surface-expressed CSPG may be involved in binding of Nalm-6 cells to laminin and that the specific sulfation pattern of chondroitin-6-sulfate may be essential in this regard.
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PMID:Characterization of cell surface-expressed proteochondroitin sulfate of pre-B Nalm-6 cells and its possible role in laminin adhesion. 866 35

Adhesion of myeloid leukemia cells to the bone marrow (BM) microenvironment is mediated in part by Beta 1 and Beta 2 integrins. Cells of the erythroleukemia line K562, derived from a patient with chronic myeloid leukemia, bind to BM fibroblasts (BMFs) but the adhesion cannot be accounted for by integrins or other known adhesion proteins including CD44 or members of the Ig or selectin families. Membrane fragments from K562 cells were radioiodinated and allowed to adhere to BMF monolayers. Adherent proteins were solubilized together with the fibroblasts, analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and visualized by autoradiography. Four adherent proteins were consistently observed. Two of these, with reduced molecular weights of 52 kD and 35 to 37 kD, were prominent. Addition of soluble thrombospondin and heparin but not fibronectin inhibited binding of K562 membrane proteins to adherent BMFs and immobilized thrombospondin- and heparin-bound K562 proteins. The 52-kD protein has a multimeric structure nonreduced and has characteristics of a glycoprotein. Its adhesion to fibroblasts is divalent cation and temperature sensitive. The 35- to 37-kD protein, whose function is divalent cation but not temperature sensitive, is phosphoinositol-linked and has characteristics identical to an adherent 35- to 37-kD protein identified on murine progenitor cells. Membrane preparations from two cases of acute myeloid leukemia showed an adherent 35- to 37-kD protein and in one case an adherent 52-kD protein without other adherent bands. A K562 subclone with reduced adherence to BMFs showed reduced amounts of adherent 52-kD and 35- to 37-kD proteins. These proteins may be responsible for the adhesion of malignant and normal hematopoietic progenitor cells to the BM microenvironment.
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PMID:Identification of novel K562 membrane proteins that adhere to bone marrow fibroblasts. 870 84

The goal of this study was to characterize salivary components of titanium pellicles and to determine how experimental pellicles affect adhesion of several strains of streptococci to titanium surfaces. Titanium experimental pellicles were formed by incubation of fresh human parotid or human submandibular-sublingual saliva on pure titanium beads. Pellicle was recovered from the beads using sodium dodecyl sulfate buffer and was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting to identify adsorbed salivary components. Streptococcus anginosus, S. oralis, and S. salivarius recovered from in vivo titanium plaque and five reference strains of streptococci were used in adhesion assays to titanium beads with and without experimental salivary pellicles. The experimental pellicle formed on titanium was found to be composed of selected proteins from human parotid and human submandibular-sublingual saliva. Salivary alpha-amylase and proline-rich proteins were found in all experimental pellicles, while sIgA, high-molecular weight mucin, and proline-rich glycoproteins were detected in one of the experimental pellicles examined. Adhesion of fresh isolates and reference stains of S. anginosus, S. oralis, and S. salivarius to saliva-coated titanium was reduced compared to that of titanium without saliva coating. However, adhesion of laboratory strains of S. gordonii and S. sanguis was found to be significantly greater to experimental pellicles of human submandibular-sublingual saliva than was the adhesion of the fresh isolates, suggesting that streptococci-colonizing implant surfaces may be inherently less adhesive than other bacterial strains. This study found that salivary pellicles are selectively formed on titanium and mediate in vitro adhesion of streptococci.
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PMID:Experimental salivary pellicles formed on titanium surfaces mediate adhesion of streptococci. 880 39

Adherence of Pseudomonas aeruginosa to cells of the respiratory tract of patients with cystic fibrosis (CF) appears to be a necessary precondition for colonization and infection. To date no effective anti-adhesive strategy has been devised for preventing P. aeruginosa infection in these vulnerable hosts. The purpose of these studies was to evaluate the potential for preventing adhesion of P. aeruginosa to epithelial cells with dextran. Dextran (3,000-70,000 MW) inhibited adhesion of P. aeruginosa to buccal and A549 pulmonary epithelial cells; the 3,000 MW compound, at 10 mM was most inhibitory. Adhesion was inhibited optimally at pH 7.4 and was independent of charge; dextran and dextran sulfate were equally inhibitory. Dextran was most inhibitory if added to the epithelial cells before the P. aeruginosa; adhesion was reversed only minimally by adding dextran after the bacteria were bound. The inhibitory effect appeared to be nonspecific because other neutral polysaccharides (glycogen and mannan) were also inhibitory, dextran blocked attachment of other respiratory tract pathogens (Staphylococcus aureus, Group A streptococcus, and Haemophilus influenzae), and because dextran did not bind specifically to bacteria or to epithelial cells. Dextran is an inexpensive and nontoxic agent and may be useful in patients with CF to prevent colonization and infection with P. aeruginosa.
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PMID:Inhibition by dextran of Pseudomonas aeruginosa adherence to epithelial cells. 897 Mar 72

Adhesion of Aspergillus fumigatus, the causative agent of human aspergillosis, to the extracellular matrix protein laminin has been previously demonstrated. This study investigated the expression of laminin receptors during swelling of conidia, a step leading to germination and subsequent colonization of tissues. Scanning electron microscopy showed that the laminin binding sites were distributed over the external rodlet layer of resting conidia. During swelling, the characteristic rodlet layer progressively disintegrated and conidia surrounded by a smooth cell wall layer appeared. Flow cytometry using fluorescein isothiocyanate-conjugated laminin demonstrated that expression of laminin receptors at the surface of conidia was swelling dependent. Resting conidia expressed high levels of laminin receptors on their surface. A gradual decrease of laminin binding was then observed as swelling occurred, reaching a minimum for 4-h-swollen conidia. This correlated with a loss of adherence of swollen conidia to laminin immobilized on microtiter plates. Trypsin pretreatment of conidia reduced laminin binding. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and ligand blotting with laminin identified in a cell wall extract a major 72-kDa cell wall glycoprotein which binds laminin. Thus, one of the initial events in the host colonization may be the recognition of basement membrane laminin by this 72-kDa cell wall surface component.
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PMID:Expression and identification of a laminin-binding protein in Aspergillus fumigatus conidia. 897 86

Cell adhesion to amino acids 2179-2198 (SN-peptide) of the laminin-1 alpha1-chain is required for lung alveolar formation in vitro (M. L. Matter and G. W. Laurie. J. Cell Biol. 124: 1083-1090, 1994). The nature of the SN-peptide receptor(s) was probed with neutralizing anti-integrin monoclonal antibodies (MAb), cells lacking integrin subunits, soluble heparin, and SN-peptide columns. Cell adhesion and spreading studies confirmed the specificity of SN-peptide and revealed adhesion to be unaffected by inclusion of anti-beta1-, anti-alpha(2-6)- or anti-alpha(V)beta5-integrin MAb. Cells lacking beta1- or alpha6-integrin subunits were fully adherent. Adhesion was heparin, but not chondroitin sulfate or heparinase, sensitive, much as is alpha-dystroglycan-laminin-1 binding. Heparin eluted approximately 155- and 180-kDa cell-surface proteins from SN-peptide columns. An additional approximately 91-kDa protein was eluted by EDTA. All were unrecognized by anti-beta1-integrin MAb. SN-peptide therefore interacts with three cell-surface proteins for which the identity remains to be determined.
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PMID:Laminin E8 alveolarization site: heparin sensitivity, cell surface receptors, and role in cell spreading. 912 7


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