UMLS:C0001511 - FACTA Search

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

Several receptors for the extracellular matrix protein collagen have been described which belong to the superfamily of receptors collectively known as integrins. Although several integrins have been shown to interact with extracellular matrix molecules via a common recognition site, arginine-glycine-aspartic Acid (RGD), within the beta 1 integrin subfamily, only the fibronectin receptor (alpha 5 beta 1) has been convincingly shown to interact with RGD. In the present study, we tested whether a collagen receptor could interact with RGD. Adhesion of an osteosarcoma cell line, MG-63, to immobilized collagen I was inhibited by the cyclic RGD-containing peptide, C*GRGDSPC* (where C* indicates that Cys participates in disulfide), and not by the linear GRGDSP or the non-RGD-containing cyclic peptide, C*GKGESPC*. Similarly, using collagen-Sepharose affinity chromatography, a heterodimeric protein could be specifically eluted from the column by the cyclic RGD peptide. Immunoprecipitations of the eluted material with monoclonal antibodies showed reactivity with the collagen receptor alpha 2 beta 1 and not alpha 3 beta 1. Our data demonstrate that RGD peptides can interact with the collagen receptor, and the differences seen with the linear and cyclic peptide suggest that the cyclic C*GRGDSPC* has a higher avidity for the receptor than the more flexible linear GRGDSP. In this paper, we provide supportive evidence that one possible mode of collagen interaction with alpha 2 beta 1 is via the RGD recognition sequence.
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PMID:The collagen receptor alpha 2 beta 1, from MG-63 and HT1080 cells, interacts with a cyclic RGD peptide. 133 Oct 77

Adhesion of N-formyl-methionyl-leucylphenylalanine-stimulated human polymorphonuclear leukocytes (PMNs) to dishes coated with laminin, fibronectin, or collagen types I and IV was dependent on the presence of magnesium (Mg2+) but not calcium (Ca2+). Addition of manganese (Mn2+) in combination with Ca2+ and Mg2+ further increased the number of PMNs adhering to the matrix proteins. Monoclonal antibody 60.3 (mAb 60.3) was equally effective at inhibiting adhesion of PMNs to all the matrix proteins. The presence of Mn2+ (50 microM), in addition to 1 mM Ca2+ and Mg2+, required higher concentrations of mAb 60.3 to inhibit adhesion of PMNs to collagens type I or IV, suggesting increased affinity of PMNs for these substrates. These findings suggest that the PMNs may regulate the affinity of CD11/CD18 for multiple ligands by binding different divalent cations to the receptor.
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PMID:Effect of divalent cations on adhesion of polymorphonuclear leukocytes to matrix molecules in vitro. 135 18

Escherichia coli and other members of the family Enterobacteriaceae express surface fibrillar structures, fimbriae, that promote bacterial adhesion to host receptors. Type 1 fimbriae possess a lectinlike component, FimH, that is commonly thought to cause binding to mannose-containing oligosaccharides of host receptors. Since adhesion of type 1 fimbriated organisms are inhibited by mannose, the reactions are described as mannose sensitive (MS). We have studied the adhesion of the type 1 fimbriated CSH-50 strain of E. coli (which expresses only type 1 fimbriae) to fibronectin (FN). E. coli CSH-50 does not bind detectable amounts of soluble FN but adheres well to immobilized plasma or cellular FN. This adhesion was inhibited by mannose-containing saccharides. By using purified domains of FN, it was found that E. coli CSH-50 adheres primarily to the amino-terminal and gelatin-binding domains, only one of which is glycosylated, in an MS fashion. Binding of the mannose-specific lectin concanavalin A to FN and ovalbumin was eliminated or reduced, respectively, by incubation with periodate or endoglycosidase. Adhesion of E. coli CSH-50 to ovalbumin was reduced by these treatments, but adhesion to FN was unaffected. E. coli CSH-50 also adheres to a synthetic peptide copying a portion of the amino-terminal FN domain (FNsp1) in an MS fashion. Purified CSH-50 fimbriae bound to immobilized FN and FNsp1 in an MS fashion and inhibited adhesion of intact organisms. However, fimbriae purified from HB101 (pPKL4), a recombinant strain harboring the entire type 1 fim gene locus and expressing functional type 1 fimbriae, neither bound to FN or FNsp1 nor inhibited E. coli adhesion to immobilized FN or FNsp1. These novel findings suggest that there are two forms of type 1 MS fimbriae. One form exhibits only the well-known MS lectinlike activity that requires a substratum of mannose-containing glycoproteins. The other form exhibits not only the MS lectinlike activity but also binds to nonglycosylated regions of proteins in an MS manner.
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PMID:Functional heterogeneity of type 1 fimbriae of Escherichia coli. 135 30

Integrins are heterodimeric cell surface proteins that mediate both cell-cell and cell-extracellular matrix interactions. We and others recently identified cDNAs encoding a novel integrin beta subunit, beta 7, in lymphocytes. We have now detected beta 7 mRNA in mouse TK-1 T lymphoma cells, which are known to express the putative Peyer's patch homing receptor alpha 4 beta P. We used an anti-peptide antiserum and a novel mAb against the beta 7 subunit to show that TK-1 cells express beta 7 as the only subunit associated with alpha 4. We conclude that beta 7 and beta P are identical. We also show that activated peripheral blood T cells express alpha 4 beta 7. We studied the function of alpha 4 beta 7/alpha 4 beta P in TK-1 cells, which do not express very late antigen (VLA)-4 (alpha 4 beta 1). Cells adhered to intact fibronectin and to a fibronectin fragment containing the CS-1 region, but not to a fragment containing the RGD sequence. Adhesion to fibronectin was inhibited by antibodies to alpha 4, suggesting that alpha 4 beta 7 is a fibronectin receptor. We confirmed that alpha 4 beta 7 binds to the CS-1 region of fibronectin using affinity chromatography. TK-1 cell adhesion to the vascular cell adhesion molecule VCAM-1 was also inhibited by antibodies to alpha 4, implying that alpha 4 beta 7 also plays a role in the adherence of lymphocytes to endothelial cells. TK-1 cell binding to fibronectin and VCAM-1 is markedly increased by brief PMA stimulation. We also found that mAbs against alpha 4 and beta 7 induce homotypic clustering of TK-1 cells. Taken together these results suggest that alpha 4 beta 7/alpha 4 beta P recognizes some or all of the same widely distributed ligands recognized by VLA-4 (alpha 4 beta 1) and that the role of alpha 4 beta 7/alpha 4 beta P may not be restricted to lymphocyte homing.
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PMID:Role of integrin alpha 4 beta 7/alpha 4 beta P in lymphocyte adherence to fibronectin and VCAM-1 and in homotypic cell clustering. 137 9

Adhesion molecules were studied in regenerating skeletal muscle immunohistochemically and ultrastructurally after a standardized trauma. In normal muscle, extracellular matrix (ECM) protein tenascin was restricted to myotendinous junctions (MTJ), while the integrin beta 1-subunit was present also on the sarcolemma. After injury, tenascin increased on the outer surface of regenerating myofibers, where cellular fibronectin also accumulated. Later, tenascin concentrated at the tips of regenerating myofibers, where new MTJs were formed. The beta 1-subunit disappeared on necrotized myofibers and reappeared on regenerating fibers in a thicker layer. The regenerating myofibers were invested by a basal lamina, except for the growth cones at the distal ends, which were laminin-negative until the formation of MTJs occurred. These results indicate that regenerating muscle cells are attached to the ECM in a way that allows both growth of the muscle cells across the scar and their use before the regeneration is completed.
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PMID:Adhesion in skeletal muscle during regeneration. 137 71

Integrins from the very late activation antigen (VLA) subfamily are involved in cellular attachment to extracellular matrix (ECM) proteins and in intercellular adhesions. It is known that the interaction of integrin proteins with their ligands can be regulated during cellular activation. We have investigated the regulation of different VLA-mediated adhesive interactions through the common beta 1 chain. We have found that certain anti-beta 1 antibodies strongly enhance binding of myelomonocytic U-937 cells to fibronectin. This beta 1-mediated regulatory effect involved both VLA-4 and VLA-5 fibronectin receptors. Moreover, anti-beta 1 mAb also induced VLA-4-mediated binding to a recombinant soluble form of its endothelial cell ligand VCAM-1. Non-activated peripheral blood T lymphocytes, unable to mediate VLA-4 interactions with fibronectin or VCAM-1, acquired the ability to bind these ligands in the presence of anti-beta 1 mAb. The anti-beta 1-mediated changes in the affinities of beta 1 integrin for their ligands were comparable to those triggered by different lymphocyte activation agents such as anti-CD3 mAb or phorbol ester. Adhesion of melanoma cells to other ECM proteins such as laminin or collagen as well as that of alpha 2-transfected K-562 cells to collagen, was also strongly enhanced by anti-beta 1 mAb. These beta 1-mediated regulatory effects on different VLA-ligand interactions do not involve changes in cell surface membrane expression of different VLA heterodimers. The anti-beta 1-mediated functional effects required an active metabolism, cytoskeleton integrity and the existence of physiological levels of intracellular calcium as well as a functional Na+/H+ antiporter. Beta 1 antibodies not only increased cell attachment but also promoted spreading and cytoplasmic extension of endothelial cells on plates coated with either fibronectin, collagen, or laminin as well as induced the rapid appearance of microspikes in U-937 cells on fibronectin. Moreover, both beta 1 integrin and the cytoskeletal protein talin colocalized in the anti-beta 1 induced microspikes. These results emphasize the central role of the common beta 1 chain in regulating different adhesive functions mediated by VLA integrins as well as cellular morphology.
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PMID:Regulation of the VLA integrin-ligand interactions through the beta 1 subunit. 137 69

Adhesion of T cells to extracellular matrix (ECM) proteins through VLA integrin receptors is crucial for lymphocyte trafficking, tissue localization and inflammatory function. We have investigated the expression of different VLA integrins (VLA-1-5) on peripheral blood (PB) and synovial fluid (SF) T lymphocytes from patients with rheumatoid arthritis (RA). Their expression on different cell types from synovial membrane (SM) is also reported. The role of VLA-4 fibronectin (FN) receptors in the interaction of activated SF T cells from RA patients with a 38-kD fragment of FN has been previously demonstrated. Here we have focused functional studies on VLA-5 as an alternative FN receptor for RA T cells. A significant higher proportion of SF T cells were able to bind to an 80-kD fragment of FN, containing the Arg-Gly-Asp (RGD) cell binding site, compared with PB T cells. This attachment was almost completely inhibited by anti-VLA-5 MoAbs as well as by RGD peptides. This enhanced capability by SF T cells appears to be independent of the level of the surface expression of the receptor and correlates better with their activation state as determined by the expression of the activation molecule AIM (CD69). The evidence for the expression of VLA heterodimers on both SF and SM cells from RA patients suggests the possible implication of ECM proteins in mediating and perpetuating inflammation in vivo.
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PMID:VLA family in rheumatoid arthritis: evidence for in vivo regulated adhesion of synovial fluid T cells to fibronectin through VLA-5 integrin. 137 52

Adhesion of normal, anchorage-dependent cells to a solid substratum leads to activation of the Na+/H+ antiporter and elevation of intracellular pH. These effects are mediated by extracellular matrix proteins, such as fibronectin, and their receptors, the integrins. Experiments using pharmacological inhibition and down-regulation of protein kinase C (PKC) in C3H 10T1/2 cells show that platelet-derived growth factor induces activation of the Na+/H+ antiporter by means of a PKC-dependent pathway in adherent cells but cannot do so in poorly adherent cells. Poorly adherent cells are, however, able to elevate intracellular pH in response to a phorbol ester, indicating that PKC and subsequent steps in the pathway are functional. These results indicate that coupling of platelet-derived growth factor to PKC activation requires cell adhesion.
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PMID:Adhesion is required for protein kinase C-dependent activation of the Na+/H+ antiporter by platelet-derived growth factor. 137 21

Hematopoietic stem cell interaction with elements of the underlying stroma is essential for sustained normal hematopoiesis. Here we have determined that adhesion receptors in the integrin family play a role in promoting adhesion of human hematopoietic stem cells to cultured human marrow stromal cells. Enriched CD34hi progenitor cells expressed VLA-4, VLA-5, and at least one or more beta 2 integrins. Homogeneous marrow stromal cell monolayers capable of supporting proliferation of cocultivated CD34hi cells expressed VCAM-1 and fibronectin (ligands for VLA-4 and VLA-5) as well as ICAM-1 (ligand for LFA-1 and Mac-1). Adhesion-blocking experiments indicated that VLA-4/VCAM-1, VLA-5/fibronectin, and beta 2-integrin/ICAM-1 pathways all are important for CD34hi cell attachment to stromal cells. Consistent with this suggestion, IL-1 stimulation of stromal cells caused both increased VCAM-1 and ICAM-1 expression and increased attachment by CD34hi bone marrow cells. In addition, CD34hi cells utilized VLA-4 to adhere to purified VCAM-1 and employed VLA-5 (and to a lesser extent VLA-4) to adhere to purified fibronectin. Together these results suggest that CD34hi stem cells may utilize multiple integrin-mediated adhesion pathways to localize within specialized microenvironmental niches created by marrow stromal cells.
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PMID:Role of beta 1 and beta 2 integrins in the adhesion of human CD34hi stem cells to bone marrow stroma. 137 10

Protein kinase C (PKC) was implicated as an important positive regulator of angio-genesis by studies showing that tumor promoting phorbol esters, which activate PKC, stimulate angiogenesis both in vitro and in vivo. Therefore, inhibitors of PKC might be expected to block angiogenesis. MDL 27032 [4-propyl-5-(4-pyridinyl)-2(3H)-oxazolone], an inhibitor of cellular protein kinases, prevented capillary-like tube formation by human umbilical vein endothelial cells (HUVEC) on basement membrane preparations, an in vitro model for angiogenic activity. MDL 27032 had an IC50 = 50 microM, whereas MDL 27044, the 4-methyl analog of MDL 27032, was less effective (IC50 greater than 100 microM). This selectivity was reflected in the relative abilities of the two compounds to inhibit PKC and protein kinase A (PKA) activity prepared from HUVEC, and also to inhibit the basic fibroblast growth factor stimulated proliferation of HUVEC. MDL 27032 (0.3 microgram/egg) also significantly inhibited neovascularization in yolk sac membranes of developing chick embryos, whereas MDL 27044 added at concentrations up to 3 micrograms/egg was not inhibitory when compared with vehicle treated controls. Adhesion of HUVEC to individual extracellular matrix proteins, including laminin, fibronectin, and fibrinogen, but not to the mixture of matrix components or collagen type I and IV, was inhibited after treatment with MDL 27032. These studies suggest that MDL 27032, may have potential as an anti-angiogenic agent because it disrupts both formation of tube-like structures by HUVEC on Matrigel and normal neovascularization in ovo. This inhibition may in part be due to altered cellular interactions with the extracellular matrix.
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PMID:Inhibition of angiogenesis in vitro and in ovo with an inhibitor of cellular protein kinases, MDL 27032. 138 May 11

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