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

The adhesion of embryonic chicken retinal cells and mouse N2A neuroblastoma cells to purified embryonic chicken retinal NCAM adsorbed on a solid substratum was examined using a quantitative centrifugal adhesion assay. Both cell types adhered to NCAM and the adhesion was specifically inhibited by monovalent anti-NCAM antibody fragments. N2A cell adhesion depended on the amount of NCAM applied to the substratum, was cation independent, and was insensitive to treatment with the cytoskeletal perturbing drugs colchicine and cytochalasin D. These results indicated that the tubulin and actin cytoskeletons were not critically required for adhesion to NCAM and make it unlikely that the cell surface ligand for NCAM is an integrin. Adhesion was however temperature dependent, strengthening greatly after a brief incubation at 37 degrees C. CHO cells transfected with NCAM cDNAs did not adhere specifically to substratum-bound NCAM and pretreatment of N2A cells and retinal cells with anti-NCAM antibodies did not inhibit adhesion to substratum-bound NCAM. These results suggest that a heterophilic interaction between substratum-adsorbed NCAM and a non-NCAM ligand on the surface of the probe cells affects adhesion in this system and support the possibility that heterophilic adhesion may be a function of NCAM in vivo.
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PMID:Evidence for heterophilic adhesion of embryonic retinal cells and neuroblastoma cells to substratum-adsorbed NCAM. 160 91

Adhesion of the neuronal cell surface to its underlying substrate plays an important role in neurite outgrowth in vitro. I have investigated the adhesive basis for neurite outgrowth in the presence of cytochalasin D, a disruptor of actin-containing microfilaments, and in the presence of vinblastine, a depolymerizer of microtubules. Scanning electron microscopy shows that cytochalasin D does not alter the branching configuration of filopodia on a laminin substrate, although processes are shorter and tapered distally in the presence of the drug. Using a standard attachment assay for the neuroblastoma x glioma cell line (NG108-15) I show that vinblastine does not influence attachment of NG108-15 cells to either plastic or laminin. Cytochalasin D-treated cells normally attach to high concentrations of a laminin substrate (20 micrograms/ml). However, when cell are seeded on a laminin substrate at lower concentrations (0.001-10 micrograms/ml), or on YIGSR, a fragment of laminin, cytochalasin D increases cell attachment. Cytochalasin D increases attachment in a dose-dependent manner when cells are seeded on plain polystyrene plastic, so that the number of cells attached to plastic in 1 microM cytochalasin D is similar to the number attached to laminin (20 micrograms/ml). Combining low concentrations of cytochalasin D and laminin results in greater attachment than with either agent alone. Mild trypsinization of the cell surface reduces the CD-enhanced attachment to plastic, indicating that a protein on the cell surface may be involved. The effect of cytochalasin D appears to be cell specific since cytochalasin D does not affect the attachment of a fibroblast cell line (NIH 3T3) to laminin and plastic.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of cytochalasin D on the adhesion of a neuroblastoma x glioma cell line (NG108-15) to laminin and plastic substrates. 237 8

Adhesion responses of fibroblasts (Balb/c 3T3 cells) and human neuron-derived (Platt neuroblastoma) cells have been examined with plasma fibronectin (pFN) adsorbed to glass surfaces derivatized with an alkyl chain and six chemical end groups interfacing with the bound pFN to test regulation of pFN function. Using new derivatization protocols, the following surfaces have been tested in order of increasing polarity: [CH3], [C = C], [Br], [CN], [Diol], [COOH], and underivatized glass [( SiOH]). For all substrata, pFN bound equivalently using either a supersaturating amount of pFN or a subsaturating amount in competition with bovine albumin. Attachment of both cell types was also equivalent on all substrata. However, spreading/differentiation responses varied considerably. F-actin reorganization was tested in 3T3 cells with rhodamine-phalloidin staining. While stress fibers formed effectively on pFN-coated [SiOH] and [Br] substrata, only small linear bundles of F-actin and a few thin stress fibers were observed on the [COOH], [Diol], and [CN] substrata; the hydrophobic substrata [( CH3] and [C = C]) gave an intermediate response. When a synthetic peptide containing the Arg-Gly-Asp-Ser sequence required for integrin binding to FNs was included in the medium as an inhibitor, additional differences were noted: Stress fiber formation was completely inhibited on [SiOH] but not on [Br] and stress fiber formation was very sensitive to inhibition on the hydrophobic substrata while the F-actin patterns on the [CN] and [COOH] substrata were unaffected. Evaluation of neurite outgrowth by neuroblastoma cells on these substrata revealed both qualitative and quantitative differences as follows: [Diol] = [COOH] greater than [SiOH] much greater than [CN] = [Br] greater than [CH3] = [C = C]. While there was poor cytoplasmic spreading and virtually no neurites formed on the hydrophobic surfaces when pFN alone was adsorbed, neurite formation could be "rescued" if a mixture of pFN with an excess of bovine albumin was adsorbed, demonstrating complex conformational interactions between substratum-bound pFN and adhesion-inert neighboring molecules. In summary, these studies demonstrate that different chemical end groups on the substratum modulate pFN functions for cell adhesion, principally by affecting the conformation of these molecules rather than the amounts bound. Furthermore, these studies confirm multiple-receptor interactions with the FN molecules in cell type-specific adhesion patterns.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Modulation of fibronectin adhesive functions for fibroblasts and neural cells by chemically derivatized substrata. 280 41

Regulation of beta 1 integrins in neurite outgrowth following N6,2'-O-dibutyryladenosine 3':5'-cyclic monophosphate (dBcAMP) treatment was investigated using the human neuroblastoma cell line TR 14. Three beta 1 integrins were identified: the alpha 1 beta 1 receptor bound collagen type I, collagen type IV and probably laminin; the alpha 2 beta 1 integrin bound collagen type I; and the alpha v beta i receptor bound fibronectin. Neurite extension was detectable as early as 30 minutes following dBcAMP treatment, was maximal after 24 hours and remained constant during treatment for 4 days. Adhesion-perturbing beta 1 subunit-specific antibodies, added together with dBcAMP, prevented the outgrowth of new neurites. During the first 24 hours of neurite outgrowth, no change was observed in the amount of beta 1 integrins nor in their topographic distribution. However, dBcAMP treatment increased the binding of alpha 1 beta 1 receptors to collagen type IV-Sepharose by a factor 2.3 +/- 0.6 (P < 0.02), while no alteration in the binding to collagen type I was detected. Moreover, neurites and growth cones were immunoreactive for collagen type IV but not for collagen type I. Consistently dBcAMP-induced neurite outgrowth was inhibited by adhesion-perturbing alpha 1 subunit-specific antibodies. Following maximal neurite outgrowth, the amount of beta 1 integrins determined by immunoprecipitation and by confocal microscopy decreased to 58.3 +/- 11.2% (P < 0.001) and to 55.4 +/- 17.5% (P < 0.001) of untreated levels, respectively, without any change in the level of beta 1 mRNA or de novo synthesized beta 1 precursor. However, pulse-chase experiments showed an increased turnover of the beta 1 subunit: the amount of beta 1 precursor that was degraded after 1 hour chase was 50.5 +/- 8.4% in cells treated for 4 days and 34.2 +/- 3.9% in untreated cells (P < 0.02); the amount of mature beta 1 after 24 hours chase was smaller in cells treated for 4 days compared to untreated cells. In conclusion, during neurite outgrowth, alpha 1 beta 1 integrins are required and acquire an enhanced binding activity for collagen type IV; but following maximal neurite outgrowth, expression of beta 1 integrins is reduced.
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PMID:Selective increase in the binding of the alpha 1 beta 1 integrin for collagen type IV during neurite outgrowth of human neuroblastoma TR 14 cells. 753 84

Because of the importance of collagens in mediating cell-substrate interactions and the association of collagens with neural recognition molecules in the peripheral nervous system, the ability of neural recognition molecules to modify the substrate properties of collagens, in particular collagen type I, for cell adhesion was determined. Two cell lines, the N2A neuroblastoma and PC12 pheochromocytoma, were investigated for their capacity to adhere to different collagen types in the absence or presence of several neural recognition molecules. Adhesion of N2A or PC12 cells and membrane vesicles from PC12 cells to collagen type I was reduced when the collagen had been preincubated prior to its application as substrate with the extracellular domain of myelin-associated glycoprotein (s-MAG) or, as control, fibroblast tenascin-C (F-tenascin). In mixture with other collagen types, s-MAG was only able to reduce the adhesiveness of collagen types III and V, but not of collagen types II and IV. F-tenascin reduced the adhesiveness of all collagen types tested. In contrast to F-tenascin, s-MAG had to be present during fibrillogenesis to exert its effect, indicating that it must be coassembled into the collagen fibril to block the binding site. Cell adhesion to collagen type I was dependent on Mg2+ or Mn2+ and inhibited by a monoclonal antibody to the alpha 1 integrin subunit. The combined observations indicate that s-MAG and F-tenascin interfere with cell binding, most probably by modifying the integrin binding site, and that the two molecules act by different mechanisms, both leading to reduction of adhesion.
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PMID:Recognition molecules myelin-associated glycoprotein and tenascin-C inhibit integrin-mediated adhesion of neural cells to collagen. 754 51

beta-Amyloid accumulates as extracellular aggregates in Alzheimer's-afflicted brain tissue, but it also is secreted by healthy tissue, for reasons not yet established. One possibility is that beta-amyloid, which contains a sequence (RHDS) homologous to the cell-binding domain of fibronectin, may modulate integrin function, a possibility supported by previous data from non-neuronal cells (Ghiso et al., Biochem. J., 288 (1992) 1053-1059). The current work shows that functional interaction with beta-amyloid peptides is also supported by integrins in neuronal cells. Experiments used the SH-SY5Y human neuroblastoma cell line, which was shown to contain integrins that mediated cell adhesion to substratum-bound fibronectin. Adhesion to fibronectin was partially blocked by synthetic beta-amyloid peptides containing the RHDS sequence. beta-Amyloid sequences adsorbed to substratum themselves were found to mediate cell adhesion, although less effectively than fibronectin. Anti-integrin blocked the peptide-mediated adhesion, at doses commensurate with those blocking fibronectin-mediated adhesion. The data support the hypothesis that beta-amyloid peptides could physiologically, and perhaps pathogenically, modulate the activity of neuronal integrins, important cell surface receptors known to control protein kinase activities, Ca2+ levels, gene expression and organization of the cytoskeleton.
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PMID:Interaction of beta-amyloid peptides with integrins in a human nerve cell line. 773 99

The neural cell adhesion molecule (NCAM) is thought to have an important role in cell-cell interactions during development. To better understand NCAM function, we studied the adhesion of mouse N2A neuroblastoma cells and Chinese hamster ovary cells to different forms of NCAM using a quantitative centrifugal cell adhesion assay that measures the rate of cell removal from experimental substrates. Embryonic brain NCAM is highly polysialylated and contains both 180- and 140-kDa polypeptide isoforms, whereas embryonic retinal NCAM is less highly polysialylated and contains primarily the 140-kDa isoform. For both forms, cell adhesion to substrate-immobilized NCAM was temperature dependent, cation independent, and time dependent. Cell adhesion to NCAM substrates was not directly affected by drugs inhibiting cytoskeletal function or cellular metabolism, suggesting that NCAM function does not depend critically on cytoskeletal function or metabolic activity. Cell adhesion to retinal NCAM was blocked by anti-NCAM antibodies, and adhesion was increased by neuraminidase treatment of both types of NCAM. Adhesion to brain NCAM was effectively blocked by anti-NCAM antibodies only after neuraminidase treatment, suggesting that these cells adhere to highly sialylated and less-sialylated NCAM by different mechanisms. We propose that multiple mechanisms of cell adhesion involving NCAM may exist in different tissues during development and that the state of polysialylation of NCAM is important in regulating the relative importance of these mechanisms.
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PMID:Multiple mechanisms of N2A and CHO cell adhesion to NCAM purified from chick embryonic brain and retina. 808 14

Adhesion of human neuroblastoma cells (SK-N-SH clone SY5Y) to laminin or collagen type IV promotes tyrosine phosphorylation of a group of proteins with molecular mass ranging from 100 to 130 kDa and of a protein of 180 kDa. The same pattern of tyrosine phosphorylation was observed when SY5Y cells were allowed to adhere to culture dishes coated with monoclonal antibodies directed to the integrin subunits expressed in the cells, alpha 1, alpha 3, and beta 1, indicating that these receptors are responsible for this signaling mechanism. Using specific antibodies we identified the focal adhesion kinase p125FAK as a component of the 100- to 130-kDa phosphoproteins. Treatment with genistein or herbimycin A, two specific tyrosine kinase inhibitors, greatly reduced the tyrosine phosphorylation of the 100- to 130- and the 180-kDa proteins in response to laminin or collagen IV. Concomitantly, neurite outgrowth on the matrix proteins was strongly inhibited. This effect was observed in two distinct neuroblastoma cell lines, SY5Y and SK-N-BE. Genistein and herbimycin A treatment did not affect cell viability nor cause retraction of preformed neurites. These data suggest that matrix-induced tyrosine phosphorylation events are involved in neurite extension.
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PMID:Role of tyrosine phosphorylation in matrix-induced neurite outgrowth in human neuroblastoma cells. 808 34

Recent studies of spinal cord development and plasticity, in chick, have demonstrated a loss of regenerative ability correlating to embryonic day (E) 13 of the 21-day developmental period. Here we describe membrane fractions from embryonic chick spinal cords as permissive or restrictive substrates for the neuron-like differentiation of neuroblastoma x glioma hybrid NG108-15 cells, in vitro. Plasma membranes were purified from the thoracic spinal cord of embryos at a series of developmental stages (E10-E18). Micro-well plates were coated with the fractions and NG108-15 cells cultured thereon. Cells adhered to the E10-coated wells and began to differentiate after 2 h, becoming highly differentiated, with neurites 2-3 times longer than the diameter of the cell body after 24 h in in culture. In contrast, cells cultured in E18-coated wells remained as clusters of undifferentiated cells of rounded morphology, even after 48 h in culture. As well, the permissive and restrictive plasma membranes were assessed semiquantitatively as the number of adhering cells after 20 h of culture. Adhesion of cells to the substrate decreased as the embryonic age of the plasma membrane substrate increased. Examination of the plasma membrane fractions, using SDS-PAGE, revealed several proteins in the 40-60 kDa range that varied substantially between E12, E14 and E18. Results of this study provide in vitro confirmation of previous in vivo findings; namely, that early embryonic spinal cord is initially permissive for neuritic outgrowth becoming restrictive around E13.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Developmental transition by spinal cord plasma membranes of embryonic chick from permissive to restrictive substrates for the morphological differentiation of neuroblastoma x glioma hybrid NG108-15 cell. 845 60

Several neuropathologic findings in infants and children with human immunodeficiency virus type-1 (HIV-1) infection are different from those observed in adults, probably related to the fact that the retroviral infection occurs in the setting of neuro-development. This report describes the interaction and biologic activity of tat, the HIV-1 trans-activating protein on human neuroblasts. Two human neuroblastoma cell lines, LAN-5 and GI-CA-N, have been studied for their capability to adhere to tat (full recombinant protein) and to two different peptide residues of it. Both cells adhere to tat and tat46-60 basic domain, although not to tat65-80 residue, which contains the RGD (arginine-glycine-aspartic acid) motif. Adhesion to collagen I was inhibited by preincubating GI-CA-N cells with tat,46-60 although not with tat,65-80 indicating the capability of the basic residue to interfere with collagen I-induced cellular adhesion. The expression of 200-kD neurofilaments induced by collagen I was not induced by tat,46-60 indicating that neural differentiation along the same pathway is not mimicked by this peptide. Neuroblast cell proliferation was not affected by adhesion to tat46-60 nor to tat.65-80 GI-CA-N cells are not permissive to HIV-1 infection. However, proviral DNA was documented in the cell lysate for 14 consecutive in vitro passages, whereas HIV-1 transcription was never detectable. This would exclude the possibility that tat would be transduced by these cells. GI-CA-N stained negative for CD4, although positive for Gal-C, which may explain HIV-1 entry. Results show that immature human neural cells interact with tat protein and/or its basic residue in vitro. A mechanism similar to that herein described would possibly be active in vivo, which may help in clarifying the pathogenic mechanisms of neurologic dysfunction and destruction of the CNS observed in infants infected with HIV-1.
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PMID:Adhesion of human neuroblasts to HIV-1 tat. 855 50


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