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)

A panel of monoclonal antibodies (mAbs) to bovine fibronectin (FN) is described which modulates either heparin binding or cell adhesion to FN, or both. A combination of competitive exclusion and binding to proteolytic fragments identified epitopes in the Hep II, Hep III/I and CBF (cell binding fragment) regions of FN. mAb A17, which bound to the CBF region, strongly inhibited the cell adhesion of BHK-21 fibroblasts, primary corneal fibroblasts and endothelial cells, and NM4 mammary adenocarcinoma cells, to FN at mAb concentrations as low as 1 microgram/ml. This mAb was not so effective at inhibiting the adhesion of B16 mouse melanoma cells. Adhesion of B16 cells to FN was more sensitive to inhibition by mAbs binding to Hep II (A2, A9, A32, A35). Of these, A32 and A35 significantly increased the binding of 35S-heparin to FN, whereas A2 and A9 did not affect it. mAbs A2, A9 and A32 showed good binding to HBF, the 40 kDa proteolytic fragment of human FN which contains both Hep II and IIICS (type III connecting segment). These mAbs inhibited B16 cell adhesion to the HBF (heparin binding fragment) by 30-50%, the greatest inhibition being shown by mAb A32. Two synthetic peptides from the HBF, CS1 (peptide 1) from the IIICS region and peptide I from the Hep II region, also inhibited B16 cell adhesion to HBF by approximately 70 and 30%, respectively. These results suggest that maximal cell adhesion to the HBF involves both CS1 and Hep II. The inhibitory effects of the two peptides were linearly additive in combination, whereas the inhibitory mAbs A2, A9 and A32 showed synergistic additive effects with each of the peptides. This points to the existence of an additional important cell binding site in Hep II, other than peptide I. Recent independent evidence for an additional cell binding site in Hep II supports this view. Melanoma cellular receptor(s) for the Hep II region may be cell surface proteoglycans but do not appear to bind to areas of Hep II with high affinity for soluble heparin, as the latter was not an inhibitor of B16 cell adhesion to the HBF. The increased effectiveness of A32 in inhibiting cell adhesion, compared to A2 and A9, may be due to conformational effects which increase the binding of soluble heparin, but reduce affinity for the cellular receptor. These results are discussed in context with other reports in the literature.
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PMID:Anti-fibronectin antibodies that modify heparin binding and cell adhesion: evidence for a new cell binding site in the heparin binding region. 138 58

The alternatively spliced type III connecting segment (IIICS) region of fibronectin contains two distinct sites that support the adhesion of melanoma cells. These sites are contained within the synthetic peptides CS1 and CS5 (residues 1-25 and 90-109 of the IIICS, respectively). Recently, the cellular receptor for the CS1 site has been identified as the integrin heterodimer alpha 4 beta 1. In this report, we have investigated the role of the CS5 sequence in melanoma cell adhesion and the identity of its receptor. Adhesion to CS5, when presented to cells as an immobilized IgG conjugate, was blocked by antifunctional monoclonal antibodies directed against either the alpha 4 or beta 1 integrin subunits, but not by antibodies against other subunits, implying that alpha 4 beta 1 is also the receptor for CS5. In peptide inhibition experiments, CS5 was inhibitory for melanoma cell spreading on both CS5-IgG and CS1-IgG conjugates; conversely, CS1 inhibited spreading on both CS1-IgG and CS5-IgG. In both cases, peptide inhibition could be outcompeted by increasing the concentration of substrate-bound conjugate. These results suggest that CS1 and CS5 are recognized by the same or overlapping sites on alpha 4 beta 1. The minimal active sequence within CS5, the tetrapeptide Arg-Glu-Asp-Val (REDV), is somewhat related to the Arg-Gly-Asp-Ser (RGDS) sequence that represents a major active site in the central cell-binding domain (CCBD) of fibronectin. When RGDS peptide homologues were tested for their ability to inhibit spreading of melanoma cells on CS1- and CS5-IgG conjugates, GRGDS, GRGES, and REDV were found to be inhibitory, while GRDGS had no effect. In contrast, spreading on a fibronectin fragment containing the CCBD was inhibited by GRGDS only. GRGDS was also able to elute alpha 4 beta 1 specifically from a CS1 affinity column, confirming directly that alpha 4 beta 1-IIICS interactions are sensitive to peptides containing this recognition motif. Because the minimal active sequence within CS1 is the tripeptide Leu-Asp-Val (LDV; Komoriya et al., manuscript submitted for publication), these findings together define a new adhesive recognition sequence, X-Asp-Y, used by alpha 4 beta 1 for binding to fibronectin. The central aspartate residue in this tripeptide is almost always essential, but some flexibility in the amino acid residues at X (glycine, leucine, or glutamic acid) and Y (serine or valine) is tolerated. Potential models for the interaction of the IIICS region with alpha 4 beta 1 are discussed.
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PMID:The CS5 peptide is a second site in the IIICS region of fibronectin recognized by the integrin alpha 4 beta 1. Inhibition of alpha 4 beta 1 function by RGD peptide homologues. 175 Sep 29

Altered T cell adherence after human immunodeficiency virus 1 (HIV-1) infection may contribute to viral pathogenesis in the acquired immune deficiency syndrome. To address this hypothesis, we assessed mechanisms of T cell adherence to extracellular matrix proteins in vitro. We found that after HIV-1 infection, both chronically infected H9 CD4+ T cells and acutely infected primary peripheral blood lymphocytes acquired the ability to adhere to the extracellular matrix glycoprotein fibronectin, to a lesser extent to type IV collagen and laminin, but not to type I collagen. H9 cells chronically infected with two of the three HIV-1 strains studied showed approximately a sevenfold increase in attachment to fibronectin, while the same cells infected with the human retrovirus HIV-2 did not. Adhesion was accompanied by changes in morphology, including marked spreading and increased filopodia. These alterations were not blocked by the protein kinase C inhibitor H-7, which did inhibit TPA-induced T cell attachment to fibronectin. Monoclonal antibodies against both the alpha 5 and the beta 1 subunits of the classical fibronectin receptor as well as an Arg-Gly-Asp (RGD) peptide inhibited attachment, whereas anti-alpha 4 monoclonal antibodies and the CS1 peptide did not. Binding to collagen IV was also inhibited by the anti-beta 1 monoclonal antibody, but not the other antibodies. Cells metabolically labeled with [35S]methionine and analyzed by immunoprecipitation with polyclonal anti-beta 1 integrin antibody showed a 2.5-fold increase in integrin synthesis in infected cells compared to uninfected controls. This increase in synthesis was associated with an increase in cell surface expression of both alpha 5 and beta 1 integrins by FACS (registered trademark of Becton Dickinson for a fluorescence-activated cell sorter) analysis. Enhanced expression of integrins such as alpha 5 beta 1 may cause T cell adherence to a variety of tissues, where released viral gene products may induce some of the tissue-specific manifestations of HIV-1 infection.
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PMID:HIV-1 infection of human T lymphocytes results in enhanced alpha 5 beta 1 integrin expression. 183 Dec 4

Adhesion to specific extracellular matrix molecules appears to be an important prerequisite for successful target organ colonization by metastasizing tumour cells. Interference in the adhesive function of malignant cells with antiadhesive agents is therefore one potential approach for preventing metastasis. Recently, synthetic peptides taken from the cell interaction sites of fibronectin have been characterized as inhibitors of cellular adhesion in vitro. Using these antiadhesive probes we have examined the role of cell adhesion to fibronectin in tumour metastasis using the B16-F10 murine melanoma model system. Two sequences from the IIICS cell-binding domain, the 25-mer CS1 peptide and the tetrapeptide Arg-Glu-Asp-Val (REDV), had no detectable activity, but the pentapeptide Gly-Arg-Gly-Asp-Ser (GRGDS), an active sequence from the central cell-binding domain, exhibited potent, dose-dependent inhibition, indicating a role for this cell recognition determinant in tumour metastasis. Under appropriate conditions GRGDS treatment afforded remarkable protection to the host; mice injected with melanoma cells and peptide were still alive 15 months after injection whereas mice injected with melanoma cells alone died within six weeks. Kinetic analyses of the retention of tumour cells in the lungs and of the vascular clearance rate of labelled GRGDS predict an early time frame of activity for the peptide. From the results of a variety of in vitro invasion and migration assays it appears that GRGDS may interfere with multiple, fibronectin-mediated adhesive and migratory events at different points of the metastatic cascade. In preliminary studies designed to optimize the therapeutic usefulness of GRGDS-like agents, peptide conjugates have been found to possess enhanced antiadhesive activity as well as an extended vascular clearance rate. In the future, therefore, these or related peptide derivatives may be potentially useful agents for the prevention of tumour metastasis.
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PMID:The cell interaction sites of fibronectin in tumour metastasis. 285 15

The modulation of adhesive interaction between lymphocyte progenitors and bone marrow stroma may critically determine the maturation and migration of B cell progenitors. mAb against CD9 and beta 1 integrins are reported to induce the homotypic adhesion of pre-B cells. We present evidence that the anti-CD9 mAb 50H.19 and ALB6 but not the proaggregatory anti-VLA-4 mAb 44H6 also enhance the Fc-independent heterotypic adhesion of the human pre-B cell lines NALM-6 and HOON to bone-marrow stromal fibroblasts (BM-FB) but not to bone marrow stroma. CD9-enhanced binding of NALM-6 cells to BM-FB was inhibited 58% by the anti-VLA-4 mAb HP2/1, 36% by the anti-VLA-5 mAb BIIG2, and 99% by their combination. The mAb effectively inhibited adhesion when prebound to NALM-6 cells but not when prebound to BM-FB. The anti-VCAM-1 mAb E1/6 inhibited CD9-enhanced adhesion by only 14% suggesting the involvement of other ligands. Adhesion was inhibited by mAbs against the COOH-terminus and central cell binding domains of fibronectin, as well as by the corresponding CS1 and RGD peptides. Adhesion was not affected by H-7 and sphingosine, inhibitors of protein kinase C. These results suggest that perturbation of CD9 on pre-B cells promotes recognition of stromal cell fibronectin by VLA-4 and VLA-5 and implicates CD9 as a novel regulator of inside-out signaling relevant to B lymphopoiesis.
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PMID:CD9-regulated adhesion. Anti-CD9 monoclonal antibody induce pre-B cell adhesion to bone marrow fibroblasts through de novo recognition of fibronectin. 751 26

Close interaction of human hematopoietic progenitors with the bone marrow microenvironment is important for the ordered progression of human hematopoiesis. Progenitor cell adhesion to stroma has a complex molecular basis, involving various cell-extracellular matrix and cell-cell interactions. We have previously shown that adhesion of colony-forming cells (CFC) to fibronectin, present in stromal extracellular matrix, involves multiple sites, including two heparin-binding synthetic peptides (FN-C/H I and FN-C/H II) and the alpha 4 beta 1 integrin-binding peptide CS1. These synthetic peptides are located in close proximity in the type III repeat 14 and the immediately adjacent type IIIcs region of fibronectin. In the current study, we evaluate receptors expressed by CFC responsible for their adhesion to fibronectin. We show that the alpha 4 beta 1 integrin mediates adhesion to CFC to the peptides FN-C/H I and CS1. Adhesion of CFC to fibronectin is also mediated by proteoglycans, because removal of cell surface chondroitin-sulfate proteoglycans resulted in decreased adhesion of CFC to FN-C/ I and FN-C/H II. The core protein of this proteoglycan was identified by immunoprecipitation as a 90-kD member of the CD44 group of adhesion molecules. Interestingly, although the proteoglycan core protein failed to adhere to FN-C/H II affinity columns, anti-CD44 monoclonal antibodies blocked CFC adhesion to FN-C/H II, indicating that these monoclonal antibodies may interfere with core protein-mediated intracellular signalling. Finally, we show that CD44 and alpha 4 beta 1 may cooperate in establishing progenitor adhesion, because anti-CD44 antibodies potentiated the adhesion-inhibitory effects of suboptimal concentrations of anti-alpha 4 or anti-beta 1 monoclonal antibodies. These results provide a working model for progenitor cell recognition of fibronectin (and possibly the marrow micro-environment) in which the coordinated action of integrins and cell surface proteoglycans is necessary for cell adhesion. This model can now be used to study the complex relationship between progenitor cell adhesion and the regulation of their proliferation and differentiation.
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PMID:Adhesion of committed human hematopoietic progenitors to synthetic peptides from the C-terminal heparin-binding domain of fibronectin: cooperation between the integrin alpha 4 beta 1 and the CD44 adhesion receptor. 752 91

Mouse mammary carcinoma mutant cell line FUA169, characterized by high GM3 ganglioside content, was established from parent cell line FM3A/F28-7, which has high lactosyl ceramide (LacCer) content but no GM3. FUA169 displays no changes in protein glycosylation, and is a typical glycolipid mutant differing from its parent in that it contains high quantities of GM3 and GlcCer, but no LacCer (see accompanying paper; Tsuruoka, T., Tsuji, T., Nojiri, H., Holmes, E. H., Hakomori, S. (1993) J. Biol. Chem. 268, 2211-2216). In contrast to parent F28-7 cells, FUA169 cells showed clear adhesion to fibronectin (FN). Several lines of evidence indicate that adhesion of FUA169 cells to FN requires the presence of GM3, which supports the function of integrin receptor. (i) Both FUA169 and F28-7 cells express the same quantity of FN integrin receptor, which consists of alpha 5 beta 1 (sensitive to RGDS peptide) and alpha 4 beta 1 (sensitive to CS1 peptide). However, adhesion to FN-coated plates, regardless of type of FN, was much higher for FUA169 than for F28-7 cells. (ii) F28-7 cells, which normally lack GM3 and adhere only weakly to FN, acquired GM3 during incubation in GM3-containing medium, and subsequently adhered strongly to FN. (iii) Cholesterol-lecithin liposomes (cholesterol was 14C-labeled) incorporating alpha 5 beta 1 receptor isolated from human placenta showed clear adhesion to FN-coated plates, and this adhesion was completely inhibited by RGDS peptide and by anti-beta 1 mAb ZH1. When liposomes included a moderate quantity of GM3 (0.22-0.44 micrograms (0.2-0.4 nmol)/55 micrograms of phosphatidylcholine, 33 micrograms of cholesterol, 5 micrograms of alpha 5 beta 1 in liposome), adhesion was enhanced significantly. In contrast, adhesion was greatly reduced below control level for alpha 5 beta 1 liposomes containing a higher quantity (2.2 micrograms; > 2 nM) of GM3. Adhesion to FN was also inhibited, but never enhanced, for alpha 5 beta 1 liposomes with similar composition but containing 0.4 nmol (or other quantities) of LacCer or GlcCer instead of GM3. These findings suggest that the greater adhesion to FN by FUA169 cells, relative to parent F28-7 cells, is due to functional support by GM3 of alpha 5 beta 1 integrin receptor.
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PMID:Regulatory role of GM3 ganglioside in alpha 5 beta 1 integrin receptor for fibronectin-mediated adhesion of FUA169 cells. 842 Sep 89

Despite the wide use of mobilized peripheral blood (PB) progenitor cells (PBPC) for clinical transplantation the mechanism(s) underlying their mobilization and subsequent engraftment are still unknown. We compared the adhesive phenotype of CD34(+) colony-forming cells (CFC) in bone marrow (BM) and PB of normal donors before and after administration of granulocyte colony-stimulating factor (G-CSF) for 5 d. G-CSF-mobilized PB CFC cells adhered significantly less to BM stroma, fibronectin, and to the alpha4 beta1 binding fibronectin peptide, CS1, because of decreased expression of the alpha4 integrin. Since incubation of BM CD34(+) cells for 4 d with G-CSF at concentrations found in serum of G-CSF- treated individuals did not affect alpha4-dependent adhesion, G-CSF may not be directly responsible for the decreased alpha4-mediated adhesion of PB CFC. Culture of G-CSF-mobilized PB CD34(+) cells with cytokines at concentrations found in BM stromal cultures upregulated alpha4 expression and restored adhesion of mobilized PB CFC to stroma, fibronectin, and CS1. Adhesion of cultured, mobilized PB CFC to stroma and CS1 could not be further upregulated by the beta1 activating antibody, 8A2. This indicates acquisition of a maximally activated alpha4 beta1 integrin once PB CFC have been removed from the in vivo mobilizing milieu. Thus, decreased alpha4 expression on CD34(+) CFC in PB may be responsible for the aberrant circulation of mobilized PB CD34(+) cells. Reexpression of a maximally activated alpha4 beta1 integrin on mobilized PB CFC removed from the mobilizing in vivo milieu may contribute to the early engraftment of mobilized PBPC.
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PMID:Mobilization and homing of peripheral blood progenitors is related to reversible downregulation of alpha4 beta1 integrin expression and function. 961 17

Fibronectin specifically binds to U937 cells (monocytic cell line) in a dose-dependent manner. The specific receptors for the RGD sequence have been identified as alphainfinity 5beta infinity 1wedge alpha infinity: IIb& beta infinity 3, and that for CS1 has been defined as alpha infinity 4& beta infinity 1. RGDS, CS1 peptide, and two peptides together showed similar inhibitory activities on this adhesion, while the 29-kD dispase-digested fragment of the C-terminal heparin-binding domain did not. Thus, the adhesion of fibronectin to U937 cells is mainly mediated by RGDS in the cell-binding domain and CS1 in the alternatively spliced region. Flow cytometry using monoclonal antibodies revealed expressions of alpha infinity 3& beta 1 infinity, alpha4 & beta infinity 1, and alpha infinity 5 beta 1, and not expression of alpha infinity 2 beta infinity 1. Adhesion of U937 cells to fibronectin-coated wells is specific and is inhibited by anti-alpha infinity 4 beta infinity 1 and anti- alpha infinity 5 beta infinity 1 monoclonal antibodies. The IC-50 for anti-alpha infinity 5 beta infinity 1 antibody was almost a log lower than the value for anti-alpha infinity 4 beta infinity 1 antibody. These results demonstrated that interactions of RGDS and CS1 sequence of fibronectin with alpha infinity 5 beta infinity 1 and alpha infinity 4 beta infinity 1& on U937 cells were required for the adhesion of U937 cells to fibronectin. These results may provide further information to understand the mechanism(s) of tumor cell adhesion and atherogenesis.
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PMID:Human Plasma Fibronectin Mediates Adhesion of U937 Cells by RGD and CS1. 1076 7

Insights into sequential leukocyte-endothelial interactions during leukocyte trafficking have been obtained through experiments using human umbilical vein endothelial cells (HUVEC) under flow conditions. To investigate leukocyte-brain endothelial cell interactions, we developed a dynamic in vitro system, using Transfected Human Brain Microvascular Endothelial Cells (THBMEC) and a parallel plate flow chamber. Human peripheral blood mononuclear cells (PBMC) were perfused across confluent THBMEC cultures at a velocity that approximates the rate found in human brain capillaries. Leukocyte-THBMEC interactions were visualized by phase-contrast microscopy, and images were captured on a CCD camera. To simulate inflammatory conditions, we activated THBMEC with the inflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma), which up-regulated chemokine and adhesion molecule expression in THBMEC without affecting the distribution of immunoreactivity for tight junction-associated proteins. PBMC adhesion was enhanced by cytokine-mediated activation of THBMEC. G protein-coupled receptor (GPCR) activation was essential for leukocyte-THBMEC interaction, as pertussis toxin (PTX) treatment of PBMC abrogated PBMC adhesion to activated THBMEC. The anti-alpha4 integrin antibody, natalizumab, infused into MS patients, significantly reduced the adhesion of their ex vivo PBMC to activated THBMEC under flow conditions. Further study showed that alternatively spliced fibronectin containing the CS1 region (FN-CS1), but not Vascular Cell Adhesion Molecule type 1 (VCAM-1), was the ligand of alpha4 integrin on activated THBMEC. Blocking FN-CS1 abrogated PBMC adhesion on activated THBMEC, while anti-VCAM-1 antibodies had no effect. These results established a novel in vitro dynamic BBB model. We also demonstrated the dependence of leukocyte-endothelial interactions in this model on alpha4 integrins and FN-CS1.
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PMID:alpha4 Integrin/FN-CS1 mediated leukocyte adhesion to brain microvascular endothelial cells under flow conditions. 1934 24


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