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

Fibronectin, an extracellular matrix component, is a ligand for very late activation antigen (VLA)-4, which is one of the beta 1-integrin family of molecules expressed by eosinophils. This study examined the effect of adherence to fibronectin on radical oxygen products from eosinophils. Adhesion of eosinophils to fibronectin resulted in enhancement of eosinophil production of radical oxygen species, as determined by luminol-dependent chemiluminescence of eosinophils stimulated with calcium ionophore. It was concluded that eosinophil adhesion to extracellular matrix via adhesion molecules may be important in the pathogenesis of allergic inflammation through eosinophil activation.
 ...
PMID:Adhesion to fibronectin augments eosinophil radical oxygen products. 754 23

Engagement of the TCR modulates the avidity of several receptors that play key roles in lymphocyte adhesion and/or signal transduction, including CD8, CD11a/CD18 (LFA-1), CD2, and several beta 1-integrins. Here, we investigated whether CD4+ T cells similarly undergo TCR-regulated adhesion to isolated MHC class II proteins through CD4. Strong adhesion of a number of CD4+ T cell clones to immobilized antigenic peptide/class II complexes was readily detectable. Adhesion to antigenic class II proteins was CD4 dependent and inhibited by pretreatment of T cells with the protein tyrosine kinase inhibitor herbimycin A, suggesting that adhesion requires TCR- and/or CD4-derived signal transduction. Treatment of T cells with anti-TCR Ab strongly increased subsequent adhesion to the extracellular matrix proteins, fibronectin and vitronectin, but, significantly, not to immobilized nonantigenic class II proteins. Suboptimal densities of antigenic peptide/class II complexes also activated adhesion of T cells to coimmobilized fibronectin or vitronectin, and this resulted in production of IFN-gamma to levels exceeding those stimulated by optimal densities of antigenic class II complexes alone. However, no augmentation of adhesion or cytokine secretion occurred when self or third party class II proteins were coimmobilized with antigenic class II complexes. The present results, therefore, suggest fundamental differences in the mechanism by which the TCR regulates coreceptor adhesion in CD4+ and CD8+ T cells.
 ...
PMID:Murine CD4+ T cells undergo TCR-activated adhesion to extracellular matrix proteins but not to nonantigenic MHC class II proteins. 756 Oct 90

The Very Late Antigen-4 receptor (VLA-4) (alpha 4 beta 1) is constitutively expressed on leukocytes and plays a role in cell trafficking, activation and development through its interaction with two alternative ligands, Vascular Cell Adhesion Molecule (VCAM-1) and fibronectin (FN). VLA-4-dependent cell adhesion is augmented by various stimuli, such as divalent cations, certain beta 1-specific monoclonal antibodies (mAbs) and cell activation. However, the steps of the adhesive process which they affect are currently undefined. In order to investigate whether or not these stimuli affect the primary step, VLA-4/ligand binding, we employed a recombinant VCAM-IgG fusion protein (VCAM-Ig) as a soluble ligand for VLA-4. Using this soluble ligand, we have directly demonstrated that the VLA-4 receptor can exist in at least three different affinity states on the cell surface. Two distinct high affinity states are induced on normal peripheral blood T cells, one by the anti-beta 1 mAb TS2/16, and one of 15-20 fold higher affinity by the divalent cation Mn2+. Interestingly, activation through the T cell receptor (TcR), through CD31 or by the Macrophage Inflammatory Protein-1 beta chemokine (MIP-1 beta) do not detectably increase VLA-4 affinity although they do augment VLA-4 dependent cell adhesion in vitro. Thus, VCAM-Ig binding defines high affinity VLA-4 receptors, revealing unique effects of the TS2/16 mAb and Mn2+ cations in vitro, and distinguishes VLA-4/VCAM interactions from subsequent steps in cell adhesion.
 ...
PMID:Vascular cell adhesion molecule (VCAM)-Ig fusion protein defines distinct affinity states of the very late antigen-4 (VLA-4) receptor. 758 6

At the time of implantation, the decidua is infiltrated by a unique population of NK cells with large granular lymphocyte morphology, which are thought to influence placental trophoblast invasion and differentiation. The mechanisms used by these cells to migrate within decidua are not known, but in other biological processes such as wound healing and tumor invasion cell-matrix interactions are important. These interactions are mediated by specific receptors, mostly belonging to the family of integrins. Decidual NK cells are observed to bind to type IV collagen and fibronectin, but not to laminin. Adhesion to collagen was inhibited with an anti-alpha 1 integrin subunit mAb, whereas adhesion to fibronectin was blocked with anti-alpha 4, -alpha 5, and -beta 1 integrin subunit mAbs. Binding of decidual NK cells to decidual stromal cells was partially blocked with mAbs to the alpha 4 and alpha 5 integrin subunits. These results provide insight into the possible mechanisms utilized by decidual NK cells for migration and retention within the pregnant uterine mucosa.
 ...
PMID:The role of integrins in adhesion of decidual NK cells to extracellular matrix and decidual stromal cells. 758 81

Cell adhesion and migration are important features in tumor invasion, being mediated in part by integrins (extracellular matrix receptors). Integrins are significantly decreased in human prostate cancer. An exception is alpha 6 integrin (laminin receptor) which persists during prostate tumor progression. We have selected high (DU-H) and low (DU-L) expressors of alpha 6 integrin from a human prostate tumor cell line, DU145, to assess experimentally the importance of alpha 6 integrin in tumor invasion. DU-H cells exhibited a four-fold increased expression of alpha 6 integrin on the surface compared to DU-L cells. Both cell types contained similar amounts of alpha 3 and alpha 5 integrin. The DU-H cells contained alpha 6 subunits complexed with both the beta 1 and beta 4 subunits whereas DU-L cells contained alpha 6 complexed only with beta 4. DU-H cells were three times more mobile on laminin as compared to DU-L, but adhered similarly on laminin. Adhesion and migration were inhibited with anti-alpha 6 antibody. Each subline was injected intraperitoneally into SCID mice to test its invasive potential. Results showed greater invasion of DU-H compared to DU-L cells, with increased expression of alpha 6 integrin on the tumor at the areas of invasion. These data suggest that alpha 6 integrin expression is advantageous for prostate tumor cell invasion.
 ...
PMID:Integrin alpha 6 expression in human prostate carcinoma cells is associated with a migratory and invasive phenotype in vitro and in vivo. 758 6

Adhesion of B lymphocytes within the different compartments of secondary lymphoid organs is essential for the function of the humoral immune response. It is not currently known how the temporary immobilization of B cells in distinct areas of this complex microenvironment is regulated. The present study aimed at defining B cell antigens that initiate binding of B cells to human tonsil sections in situ. Engaging the B cell antigens CD19 and target of an antiproliferative antibody 1 (TAPA-1) with monoclonal antibodies induced adhesion of these B cells to the interfollicular stroma. This binding occurred through the integrin alpha 4 beta 1 on the B cell surface and via the extracellular matrix protein fibronectin expressed in the interfollicular compartment of the tonsil. Signaling through either antigen, CD19 or TAPA-1, depended on tyrosine kinases. Binding induced by engaging CD19 required an intact cytoskeleton, whereas TAPA-1-transmitted adhesion did not. We suggest that CD19 and TAPA-1 have a novel and unique function by regulating an alpha 4 beta 1/fibronectin-mediated binding of B cells to the interfollicular stroma of lymphoid tissues.
 ...
PMID:Engaging CD19 or target of an antiproliferative antibody 1 on human B lymphocytes induces binding of B cells to the interfollicular stroma of human tonsils via integrin alpha 4/beta 1 and fibronectin. 759 90

Collagen type VI, which forms characteristic microfibrillar structures, is assembled from three individual alpha(VI) chains that form a short triple helix and two adjacent globular domains. Expression of all three alpha (VI) collagen chains in the human bone marrow (BM) microenvironment could be detected by chain-specific antibodies in tissue sections and in the adherent stromal layer of long-term BM cultures. In functional studies, collagen type VI was shown to be a strong adhesive substrate for various hematopoietic cell lines and light-density BM mononuclear cells. The adhesive site within the molecule seems to be restricted to the triple helical domain of all three alpha (VI) chains, because individual alpha (VI) chains were not active in the attachment assays. Adhesion of the hematopoietic cell lines to collagen VI was dose-dependent and could be inhibited by heparin. Although the triple helix contains several RGD sequences, adhesion of the hematopoietic cell types to collagen VI could be blocked neither by RGD-containing peptides nor by a neutralizing antibody to the beta 1 integrin subunit. In combination with an antiadhesive substrate, the binding properties of collagen VI could be downregulated. These data suggest that this collagen type may play an important role in the adhesion of hematopoietic cells within the BM microenvironment.
 ...
PMID:Collagen type VI in the human bone marrow microenvironment: a strong cytoadhesive component. 765 6

An overview is presented of our studies on the interaction between blood-borne tumor cells and the tissues where metastases are formed, in particular the liver. Using blocking antibodies and tumor cell mutants, we have identified the adhesion molecules involved, which so far are all integrins. Strikingly, tumor cell lines that are quite similar, and invade in a comparable fashion, use distinct integrins. Lymphomas that invade the liver massively and diffusely use LFA-1 or fibronectin receptors to adhere to hepatocytes. We have obtained evidence that LFA-1 is activated during the interaction by factors that act through G-protein-coupled receptors, and preliminary results suggest that the same may be true for the fibronectin receptors. Whereas TA3/Ha murine mammary carcinoma cells adhere to hepatocytes via alpha 6 beta 4, TA3/St variant cells of the same tumor bind via the fibronectin receptor alpha 5 beta 1. Adhesion of the TA3/Ha cells appears to be impaired by the mucin epiglycanin that is abundantly present on the surface of these cells.
 ...
PMID:The role of integrins and integrin activation in liver metastasis. 765 36

Transfection of murine metastatic B78H1 cells (derived from B16 melanoma) with a syngeneic H-2Kb gene was used to study the effect of Major Histocompatibility Complex (MHC) gene products on tumour cell adhesion to endothelial cells and matrix proteins and the involvement in the metastatic process. H-2Kb-expressing transfectants showed a reduced adhesion to endothelial surfaces of different origin (four murine endotheliomas and human umbilical vein endothelial cells) when compared to parental B78H1 cells and to controls transfected with pSV2neo alone. On the average a 50-70% reduction in adhesion to endothelial cells was observed among H-2Kb transfectants. H-2Kb transfectants had a reduced expression of the alpha 4 integrin subunit, moreover the adhesion of Neo-transfected clones to endothelial cells was reduced to the levels of H-2Kb transfectants by antibodies directed against the beta 1 subunit and the endothelial VCAM-1 molecule, thus suggesting an impairment of the VLA-4/VCAM-1 interaction in H-2Kb transfectants. Adhesion to extracellular matrix components was also strongly decreased: in general the adhesion of H-2Kb cells showed a 50-75% inhibition with respect to Neo or parental controls. The highest difference was observed in adhesion to vitronectin and laminin, the lowest in adhesion to fibronectin. Reduction in adhesive properties of H-2Kb-expressing transfectants could be involved in the reduced metastatic ability, evaluated by means of intravenous injection of cells: H-2Kb transfectants yielded less than ten lung colonies, while all controls produced more than 100. Our data indicate that expression of a single class I MHC gene can significantly alter the metastatic phenotype of MHC-negative tumour cells and this could be related to a general alteration of tumour cell adhesive interactions.
 ...
PMID:Decreased adhesion to endothelial cells and matrix proteins of H-2Kb gene transfected tumour cells. 769 18

Monocytes but not unstimulated lymphocytes adhered to human neurons and astrocytes in primary culture, as demonstrated by double labeling. The expression of VCAM-1 was higher on neurons than on astrocytes, whereas that of beta 1, alpha 1, alpha 2, alpha 4 and alpha 5 chains from the integrins and of ICAM-1 was identical on both types of cells. The expression on neurons of ICAM-1, but not of integrins, was up-regulated by exogenous tumor necrosis factor (TNF) alpha, interleukin (IL)-1 alpha and interferon (IFN)-gamma. The same was observed on astrocytes associated with a sharp increase in the expression of VCAM-1. Adhesion between monocytes and neurons or astrocytes was 80% inhibited by mAbs directed against the CR3 determinant on monocytes or against ICAM-1 on neural cells but not by any of the other mAbs against adhesion proteins that were tested. Finally, the level of endogenous production of IL-1 alpha and TNF alpha was greatly increased after the adhesion of monocytes to CNS cells.
 ...
PMID:Adhesion to human neurons and astrocytes of monocytes: the role of interaction of CR3 and ICAM-1 and modulation by cytokines. 770 27


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>