Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the role of mucin-type (O-linked) carbohydrate chains of tumor target cells in the recognition by macrophages through a Gal/GalNAc-specific calcium-dependent lectin. Binding of a soluble form of this lectin to P815 mastocytoma cells was increased by treatment with benzyl-GalNAc, which presumably inhibited the extension of mucin-type carbohydrate chains. The levels of cell surface expression of GalNAc residues were elevated after benzyl-GalNAc treatment, as revealed by the binding of Vicia villosa agglutinin B4 and Dolichos biflorus agglutinin. Adhesion of treated P815 cells to this lectin immobilized on plastic surfaces also increased. Furthermore, the binding of P815 cells to macrophage-like RAW 264.7 cells and to peritoneal macrophages also increased after the same treatment. We concluded that elevated levels of cell surface terminal GalNAc in mucin-type carbohydrate chains increased accessibility of P815 cells to macrophages through Gal/GalNAc-specific calcium-dependent lectins.
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PMID:Enhancement in accessibility to macrophages by modification of mucin-type carbohydrate chains on a tumor cell line: role of a C-type lectin of macrophages. 788 11

1. Adhesion of neutrophils to vascular endothelium plays an important role in inflammation and thrombosis. Modulation of adhesion may be therapeutic in these conditions. 2. A flow model was used to quantify adhesion of neutrophils to human cultured umbilical vein endothelial cells. The time course of the neutrophil response to activation by N-formyl-methionyl-leucylphenylalanine (fMLP, 10(-7) M) was studied and the inhibitory effects of the calcium-channel blockers, nitrendipine and nifedipine, were investigated. 3. Neutrophils adhered firmly to the endothelial cells without rolling, but initial attachment was highly dependent on shear stress; doubling the stress from 0.05 to 0.1Pa decreased the number of neutrophils adhering by over 80%. 4. Adhesion rapidly increased after activation of neutrophils by fMLP, peaking at 1-3 min post-treatment, and then decreased over the next 10-12 min. A monoclonal antibody to the beta 2-integrin component CD18 inhibited adhesion by over 80% for activated or unactivated cells. 5. The Ca-channel blocker, nitrendipine, but not nifedipine, significantly inhibited the fMLP-induced increase of adhesion in a dose-dependent manner (10(-8) to 10(-6) M). Dihydropyridines may be useful agents for modifying neutrophil function.
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PMID:Effect of activation on adhesion of flowing neutrophils to cultured endothelium: time course and inhibition by a calcium channel blocker (nitrendipine). 790 73

Human peripheral blood eosinophils adhered specifically to microtitre plates coated with plasma fibronectin (Fn) in a dose- and time-dependent fashion. Adhesion was optimal at 60 min at a concentration of 100 micrograms/ml. Adherence to Fn was up-regulated by platelet-activating factor (PAF; optimum concentration of 10(-6) M) and was significantly inhibited by a polyclonal anti-Fn antibody (P < 0.05). The following evidence suggested that eosinophil adhesion to Fn was mediated by alpha 4 beta 1: (1) eosinophil adherence to Fn was not inhibited by an Arg-Gly-Asp-Ser (RGDS) synthetic peptide; (2) there was a dose-dependent adherence of eosinophils to microtitre plates coated with the 40,000 MW proteolytic fragment of Fn that contains the CS-1 alpha 4 beta 1 binding region, whereas adherence to the 120,000 MW chymotryptic fragment of Fn, which contains the RGD-dependent binding site, was weak and only observed at high concentrations (> 250 micrograms/ml); (3) significant inhibition of eosinophil adherence to Fn was achieved by monoclonal antibodies (mAb) against the alpha chain of VLA-4 but not by a mAb against CD45 or a mouse myeloma antibody as negative controls. After adhesion to Fn, eosinophils were investigated for their capacity to release leukotriene C4 in response to stimulation with a suboptimal concentration of calcium ionophore (2 x 10(-6) M). Significant enhancement of release was detected with Fn-coated plates but not with the control bovine serum albumin (BSA) (P < 0.01). Furthermore, this enhancement was significantly inhibited by the alpha 4 beta 1 mAb HP2/1 (P < 0.05) but not by an anti-CD45 mAb. From these studies we conclude that (1) alpha 4 beta 1 (VLA-4) integrin is a major receptor for Fn on human eosinophils and (2) adhesion to Fn may prime eosinophils for mediator release during allergic inflammation.
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PMID:Adhesion to fibronectin primes eosinophils via alpha 4 beta 1 (VLA-4). 792 93

Platelet/Endothelial Cell Adhesion Molecule-1 (PECAM-1) is a 130-kDa integral membrane glycoprotein found on the surface of human platelets and leukocytes, and at the intercellular junctions of endothelial cells. PECAM-1 is a member of the immunoglobulin (Ig) gene superfamily, with six Ig-like loops in the extracytoplasmic domain, a 19-residue transmembrane domain, and a 118-amino acid cytoplasmic tail that contains potential sites for phosphorylation and lipid modification that could potentially modulate its adhesive properties and/or subcellular distribution. Antibodies to PECAM-1 interfere with the ability of endothelial cells to form normal cellular junctions, suggesting that PECAM-1 functions in forming or stabilizing the vascular bed. Anti-PECAM-1 antibodies also have been reported to block neutrophil and monocyte chemotaxis in response to lipopolysaccaride, suggesting that PECAM-1 may play a role in leukocyte motility. PECAM-1-transfected murine L cells, but not untransfected L cells, aggregate in a calcium- and PECAM-1-dependent manner, demonstrating directly that PECAM-1 functions as a cell-cell adhesion molecule. PECAM-1 becomes highly phosphorylated in response to cellular activation and, coincident with phosphorylation, associates with the cytoskeleton of activated, but not resting platelets. The engagement of PECAM-1 with the platelet cytoskeleton enables it to move large distances within the plane of the membrane and may similarly account for the ability of PECAM-1 to localize to the intercellular borders of endothelial cells once cell-cell contact has been achieved. Finally, engagement of PECAM-1 causes up-regulation of integrin function on leukocytes, implicating PECAM-1 as a trigger molecule that may regulate leukocyte trafficking through the vessel wall.
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PMID:The role of PECAM-1 in vascular cell biology. 801 65

Interactions between cells and extracellular matrix are in large part mediated by integrins in divalent cation-dependent processes. Integrins are important for cell differentiation, proliferation, and migration during development and repair of diverse tissue types. The roles played by integrin adhesion receptors in the lung are just beginning to be investigated. It is plausible that integrins play a central role in mediating lung basement membrane influences on alveolar epithelial type II cell localization and differentiation. The current studies were carried out to determine the patterns of alveolar epithelial cell adherence and spreading on different substrata and their divalent cation and RGD requirements. We utilized a rat type II cell-derived cell line, LM5, and a human alveolar cell carcinoma cell line A549. Both cell types showed similar responses to divalent cations. Adhesion and spreading on different extracellular matrix components had different divalent cation requirements. Mn2+ enhanced adhesion and spreading on fibronectin (FN), type IV collagen, and laminin, but not on type I collagen or plastic. Mn(2+)-enhanced cell adhesion to FN was RGD-dependent and partially inhibited by an anti-alpha 5 integrin antibody. Small increases in Ca2+ concentration (0.1-0.5 mM), but not Mg2+, suppressed Mn(2+)-mediated adhesion and spreading. Thus, variations in the relative divalent cation concentrations in the vicinity of the integrin-ligand complex may modulate the receptor-acceptor interactions. These results support the view that alterations in extracellular divalent cations are important regulators of alveolar epithelial cell interactions with lung basement membrane.
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PMID:Divalent cation-dependent regulation of rat alveolar epithelial cell adhesion and spreading. 802 Jun 8

To elucidate the pathogenesis of sarcoidosis, we mainly investigated the surface molecules including adhesion molecules on BAL T cells and the functions of BAL T cells such cytokine production, [Ca2+] mobilization, PKC expression. Results are following. Adhesion molecules were up-regulated on BAL T cells compared with peripheral T cells, but cytokine production was decreased via TcR stimulation through [Ca2+] mobilization was occurred. PKC isozyme alpha expression was decreased compared with peripheral blood T cells.
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PMID:[Specificity of surface antigen and function of BAL T cells]. 804 24

E- and P-cadherin are calcium (Ca2+)-dependent cell adhesion molecules important in the morphogenesis and maintenance of skin structure. By use of flow cytometry and specific antibodies, we now show that cultured human melanocytes express E- and P-cadherin on their surfaces, and that these molecules have the same characteristics as reported for other cell types. Specifically, melanocyte cadherins are sensitive to trypsin digestion in the absence of Ca2+ and are protected from trypsin degradation by Ca2+, and are functional at 37 degrees C but not at 4 degrees C. We further show that melanocytes contain mRNA transcripts encoding both E- and P-cadherin. Adhesion of cultured melanocytes to keratinocyte monolayers is abolished by pre-treatment of the melanocytes with trypsin/EDTA, which degrades E- and P-cadherins, is greatly reduced by anti-E-cadherin antibodies and is slightly reduced by antibodies to P-cadherin, alpha 2, alpha 3 and beta 1 integrins. In contrast to normal melanocytes, eight of nine melanoma cell lines lacked E-cadherin (or expressed markedly reduced levels) and five were negative for P-cadherin. Melanoma cells also failed to adhere to keratinocyte monolayers. These results demonstrate that normal human melanocytes express functional E- and P-cadherin and that E-cadherin is primarily responsible for adhesion of human melanocytes to keratinocytes in vitro. In addition, transformed melanocytes express markedly reduced levels of E- and P-cadherin, and exhibit decreased affinity for normal keratinocytes in vitro, suggesting that loss of cadherins may play a role in melanoma metastasis.
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PMID:E-cadherin is the major mediator of human melanocyte adhesion to keratinocytes in vitro. 805 51

The adherence of lymphocytic MOLT-4/clone 8 cells and normal human peripheral blood mononuclear cells (PBMCs) to primary cultures of term human syncytiotrophoblast has been characterized. Adherence was measured using a fluorescence-based assay in which leukocytic cells were labelled with calcein-AM. Adherence of MOLT cells to syncytiotrophoblast increased in a time-dependent fashion up to about 4 h after which adhesion decreased. Adhesion was detectable at 4 degrees C but was greatly reduced compared to that seen at 37 degrees C. Binding increased linearly as the ratio of MOLT cells to trophoblast was increased. Scanning and transmission electron microscopy of MOLT cell-trophoblast cocultures revealed lymphocytes adherent to the free microvillous surface of the syncytiotrophoblast masses. MOLT cells also adhered to cytotrophoblast but the extent of binding was lower than to syncytiotrophoblast. Normal human peripheral blood mononuclear cells adhered to syncytiotrophoblast. Preincubation of trophoblast cells with trypsin in the presence of calcium had no effect on subsequent adhesion of MOLT cells. However, preincubation of trophoblast cells with trypsin in the absence of divalent cations reduced subsequent adhesion. Adhesion of MOLT cells to syncytiotrophoblast was dependent on magnesium and calcium. These results show for the first time that lymphocytic cells adhere to isolated human syncytiotrophoblast and raise the possibility that this may be an important phenomenon in vivo.
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PMID:Adhesion of lymphocytic cells to human trophoblast cells in vitro. 810 3

Adhesion of CD8+ CTL to purified class I proteins has been shown to be regulated by the TCR: nonactivated CTL do not adhere to immobilized class I proteins (non-Ag), but adhesion becomes readily detectable upon treatment of the CTL with fluid-phase anti-TCR mAb. Signals for up-regulating CD8 adhesion do not appear to involve products of the PI pathway, as neither increased production of inositol phosphates or mobilization of [Ca2+]i can be detected in response to the fluid-phase anti-TCR mAb, but both occur when the CTL then bind to class I protein. The lack of a role for phosphoinositide pathway products in up-regulating CD8 was confirmed by the inability of phorbol ester or calcium ionophore to substitute for TCR mAb in triggering adhesion to class I proteins. Instead, both phorbol ester and calcium ionophore inhibited the anti-TCR mAb-stimulated adhesion to class I. Inhibitors of protein tyrosine kinases also block TCR-activated, CD8-dependent adhesion to class I, and concomitantly block inositol phosphate release, Ca2+ mobilization and degranulation. Inhibition of signaling and response does not appear to be caused solely by the inhibition of adhesion to class I, however, because these inhibitors also block signaling in response to immobilized anti-TCR mAb under conditions in which binding of other receptors to their ligands is not necessary to initiate phosphoinositide hydrolysis and degranulation. These results lend further support for a model in which CTL activation involves a cascade of adhesion and signaling events initiated by the TCR and propagated by CD8 and additional cell-surface receptors.
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PMID:Signals for activation of CD8-dependent adhesion and costimulation in CTLs. 815 59

Two isoforms of laminin were extracted from human placenta by neutral buffer containing EDTA, copurified through several steps and finally separated by Mono Q anion exchange chromatography. One variant consisted of disulphide-linked 340, 230 and 190 kDa subunits, which were identified by immunoblotting as Am, B1e and B2e chains. In the other variant, the B1e chain was replaced by B1s of 180 kDa. After rotary shadowing, both variants showed a similar cross-shaped structure. The nidogen content of these laminins was substoichiometric and variable (3-70%), indicating loss by endogenous proteolysis. Yet both human isoforms were able to bind mouse nidogen with an affinity (Kd approximately 0.5 nM) comparable to that of AeB1eB2e laminin from a mouse tumour. Since the binding site is known to be contributed by a single EGF-like motif of the B2e chain, this demonstrates that activity of this site is independent of chain assembly. Binding activity of both isoforms to collagen IV and the heparan sulphate proteoglycan perlecan was correlated to the nidogen content and could be enhanced by adding nidogen. Binding to heparin was only partial and heparin did not inhibit perlecan binding. This indicated a crucial role for nidogen in mediating the integration of these laminin isoforms into basement membranes. Variant AmB1sB2e showed calcium-dependent binding to fibulin-1, while only a little activity was found for AmB1eB2e. Both isoforms promoted adhesion and spreading of several cell lines. Adhesion could be completely inhibited by antibodies to the integrin beta 1 subunit but not, or only weakly, by antibodies against beta 3, alpha 2, alpha 3, alpha 5 and alpha 6 subunits. No inhibition was observed with an Arg-Gly-Asp-containing peptide.
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PMID:Protein binding and cell adhesion properties of two laminin isoforms (AmB1eB2e, AmB1sB2e) from human placenta. 817 20


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