UMLS:C0001511 - FACTA Search

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)

There is evidence that mature megakaryocytes migrate into sinusoids, enter the blood and fragment in the vascular bed. We wondered whether differences in expression of adhesion antigens could be associated with the egress of megakaryocytes from bone marrow into the peripheral blood or the fragmentation into platelets. Megakaryocytes from human marrow were purified by counterflow centrifugal elutriation followed by a glycoprotein Ib-dependent agglutination procedure. Megakaryocytes from central venous blood and pulmonary arteries were purified by counterflow centrifugal elutriation alone. Adhesion antigens were labelled in an immunohistochemical assay. Both bone marrow megakaryocytes and platelets from healthy volunteers stained > 75% positive for CD36, CD41, CD42, Cdw49b (alpha subunit VLA2), Cdw49e (alpha subunit VLA5), Cdw49f (alpha subunit VLA6) and CD62. Circulating megakaryocytes, although > 75% positive for CD41, had, unlike platelets and bone marrow megakaryocytes, a reduced and remarkable heterogeneous (5-100% positive) labelling with antibodies against Cdw49b, Cdw49e, Cdw49f. These results could be confirmed by comparing the bone marrow megakaryocytes, circulating megakaryocytes and platelets from 7 patients that were recovered and processed at the same time. Morphologically mature, circulating megakaryocytes have, unlike bone marrow megakaryocytes, a heterogeneous expression of adhesion antigens, especially of Cdw49b, Cdw49e, and Cdw49f.
...
PMID:Expression of adhesion antigens of human bone marrow megakaryocytes, circulating megakaryocytes and blood platelets. 144 25

The regulation of extracellular matrix (ECM) protein receptor expression was followed in the human promonocytic cell line U937 before and after stimulation either with PMA or various cytokines implicated in monocytopoiesis. On undifferentiated U937 cells, alpha-chains of very late Ag (VLA)-4, VLA-5, and VLA-6 were constitutively expressed whereas alpha-chains of VLA-2 (alpha 2) and vitronectin receptor (alpha V) were not. Maturation of U937 cells with PMA resulted in a marked decrease in alpha 4 expression (25% of control by day 5), and a small but significant increase in the expression of alpha 2 and alpha v over 4 days of stimulation. Unstimulated U937 cells attached to fibronectin (FN) but not to laminin (LM), collagens I/IV-coated surfaces. After PMA stimulation, U937 cells exhibited enhanced adherence on FN and expressed the ability to adhere to LM. PMA stimulation also promoted U937 spreading both on FN and LM. Adhesion on FN all along the maturation pathway was specifically and totally inhibited by anti-alpha 5 mAb but not by anti-alpha 4 mAb. Anti-beta 1, anti-alpha 6, anti-alpha 2, and anti-alpha v mAb, as well as Tyr-Ile-Gly-Ser-Arg and Arg-Gly-Asp synthetic peptides from LM, had no effect on adhesion of PMA-stimulated cells on LM, implying that U937 cell adherence to LM is mediated through hitherto distinct receptors. In the presence of rIFN-gamma, differentiating U937 cells did not adhere to LM and lost the capacity to bind to FN. Loss of adhesion to FN was correlated with the concomitant decrease in the expression of alpha 4 and alpha 5 integrin subunits. In contrast, TGF-beta 1 mimicked most of the effects of PMA by enhancing the attachment of maturating U937 cells on FN through alpha 5 receptors and by promoting adherence to LM. TGF-beta 1 stimulation also promoted U937 cell spreading on both FN- and LM-coated surfaces. The data suggest that inflammatory cytokines such as IFN-gamma and TGF-beta 1 may be critically important in the homing of monocytic cells at sites of inflammation by modulating cell-surface expression of ECM receptors.
...
PMID:IFN-gamma and transforming growth factor-beta 1 differently regulate fibronectin and laminin receptors of human differentiating monocytic cells. 153 26

The adhesion of platelets to purified laminin under flow conditions was investigated. Adhesion to laminin was strongly dependent on the presence of divalent cations. In the absence of cations platelet adhesion (8% coverage in 5 minutes) was maximal at a shear rate of 100/s and no adhesion could be detected at shear rates above 800/s. In the presence of 0.8 mmol/L Mg2+ and 2 mmol/L Ca2+ platelet adhesion reached its maximum (30% coverage) around 800/s. At 1,800/s platelets still adhered to purified laminin (coverage of 6%). Antibodies against the E8 domain of laminin and antibodies against the alpha 6 and beta 1 chains of platelet membrane glycoprotein very late activation antigen-6 (VLA-6), completely inhibited adhesion. No inhibition was found with antibodies against glycoprotein IIb:IIIa, against the alpha 2 chain of VLA-2, and against the alpha 5 chain of VLA-5. Fibronectin and von Willebrand factor were not involved in laminin-dependent adhesion. Anti-VLA-6 partly inhibited platelet adhesion to the extracellular matrix of endothelial cells at shear rates below 800/s. Preincubation of the matrices with antilaminin E8 antibodies did not influence the adhesion. These results show that purified laminin supports platelet adhesion and that the presence of VLA-6 is important for platelet adhesion under flow conditions. The protein in the matrix with which VLA-6 interacts is currently unknown.
...
PMID:Platelet adhesion to laminin: role of Ca2+ and Mg2+ ions, shear rate, and platelet membrane glycoproteins. 173 1

The integrin heterodimer VLA-2, previously known as a collagen receptor, is now shown also to be a laminin receptor. Adhesion of the human melanoma cell line LOX to laminin was inhibited by anti-VLA alpha 2 antibodies. Because VLA-2-mediated LOX cell attachment to laminin was not inhibited by digestion with collagenase, collagen contamination of laminin was not a factor. In addition, VLA-2 from LOX cells bound to immobilized laminin, and binding was disrupted by EDTA but not by Arg-Gly-Asp (RGD) peptides. VLA-3 also bound to laminin-Sepharose, although less avidly than VLA-2. Thus, at least four separate members of the integrin beta 1 subfamily serve as laminin receptors--i.e., VLA-2 and VLA-3 (this study) together with VLA-1 and VLA-6 (other reports). Whereas LOX and other cell lines used VLA-2 as both a laminin and collagen receptor, fibroblast VLA-2 mediated collagen but not laminin binding. Likewise, VLA-2 from platelets did not interact with laminin. Despite this functional discordancy, VLA-2 from laminin-binding and nonbinding sources was indistinguishable by all immunochemical and biochemical criteria examined. Thus, functional differences in VLA-2 may be due to cell type-specific modulation.
...
PMID:The human integrin VLA-2 is a collagen receptor on some cells and a collagen/laminin receptor on others. 255 34

Adhesion of platelets to the subendothelium is an essential step in hemostasis and thrombosis. Several receptors for adhesive macromolecules have been identified on platelets and are included in the integrin family. To clarify the role of platelet membrane glycoproteins in the interaction of platelets with the subendothelium, 51Cr-labeled platelet adhesion assay and antibody-blocking experiments were performed by using in vitro cultured subendothelium under the static condition. The platelet adhesion in this assay was inhibited by anti-GPIa (VLA-2), GPIc (VLA-5) and -GPIc'-(VLA-6) antibodies, while anti-GPIb and -GPIIb/IIIa antibodies had no effect. Platelets from the patients with Glanzmann's thrombasthenia could also attach to the subendothelium, whereas those from a patient whose platelets lacked GPIa failed to attach to the extracellular matrix (ECM). The monoclonal antibodies against fibronectin and laminin which recognized the cell binding domain of these molecules inhibited the platelet adhesion when they were pre-treated with ECM. Furthermore, antibody-blocking experiments revealed that the percent inhibition by the combination of anti-GPIa, -GPIc and -GPIc' antibodies used herein was approximately 75%. They did not completely inhibit the attachment. These results suggest that the interactions of collagen, fibronectin and laminin with their receptors on platelets are involved in the mechanism of platelet adhesion to subendothelium.
...
PMID:Role of membrane glycoproteins in the interaction of blood platelets with the vessel wall--the study on platelet adhesion to in vitro cultured subendothelial matrix. 262 57

We have purified the platelet membrane glycoprotein Ia-IIa complex by detergent solubilization and sequential affinity chromatography on Concanavalin A-Sepharose and collagen-Sepharose. The complex, which is identical to the VLA-2 complex of lymphocytes and other cells and contains subunits of 160 and 130 kD on SDS-PAGE, was labeled with 125I and incorporated into phosphatidyl choline liposomes. The liposomes, like intact platelets, adhered to collagenous substrates in an Mg++-dependent manner with a K'a(Mg++) of 3.5 mM. Little adhesion of the liposomes to collagen occurred when Mg++ was replaced by Ca++ or EDTA. Calcium ions inhibited the Mg++-dependent adhesion with a K'i(Ca++) of 5.5 mM. Liposomes containing the Ia-IIa complex adhered to substrates composed of types I, II, III, and IV collagen, but did not effectively adhere to substrates composed of type V collagen or gelatin. Adhesion to collagen was specific. The liposomes did not adhere to fibronectin, vitronectin, laminin, thrombospondin, fibrinogen, or von Willebrand factor substrates. The monoclonal antibody P1H5, which specifically immunoprecipitated the Ia-IIa complex, also specifically inhibited the Mg++-dependent adhesion of both platelets and Ia-IIa-containing liposomes to collagen substrates. These findings provide additional evidence that the platelet membrane Ia-IIa complex is the mediator of Mg++-dependent platelet adhesion to collagen and suggest that the VLA-2 complex may also function as an Mg++-dependent collagen receptor in other cells.
...
PMID:The membrane glycoprotein Ia-IIa (VLA-2) complex mediates the Mg++-dependent adhesion of platelets to collagen. 271 83

Human fetal livers contain progenitor cells that become mast cells after 4 weeks of culture with recombinant human stem cell factor. Expression of cell surface CD29 (beta 1), CD18 (beta 2), CD61 (beta 3), and beta 5 integrins was investigated on such cells by flow cytometry and adhesion measurements. High surface expression of CD49e, CD51, and CD61 along with kit was apparent by 4 weeks of culture, whereas expression of each at day 0 was low to undetectable. CD29 and CD49d were detected on cells from day 0 to 4 weeks of culture; CD49b, CD49c, CD49f, CD18, and CD54 expression was negligible. The fetal liver-derived mast cells spontaneously adhered to vitronectin. No evidence for degranulation was found during vitronectin-dependent adhesion. Adhesion occurred in part through the CD61/CD51 receptor. No evidence for adhesion to vitronectin through CD29 and beta 5 integrins was obtained. Almost all of the vitronectin-adherent cells expressed CD51, CD61, kit, and tryptase, and exhibited metachromasia with toluidine blue. Thus, among the fetal liver-derived cells, developing mast cells were selectively adherent to vitronectin. These mast cells and the other cell types present also adhere spontaneously to fibronectin and to laminin, this adhesion being partially inhibited by antibodies against CD61 and CD29 integrins. In conclusion, human mast cells acquire functional vitronectin receptors as they develop from fetal liver progenitors under the influence of rhSCF. This may be important for the recruitment, localization, and retention of developing mast cells.
...
PMID:Human mast cells derived from fetal liver cells cultured with stem cell factor express a functional CD51/CD61 (alpha v beta 3) integrin. 754 4

An inhibitor of the adhesion of human platelets to collagen was identified in soluble extracts of the soft tick Ornithodoros Moubata and purified by four chromatographic steps. The isolated inhibitor, TAI (Tick Adhesion Inhibitor), is a approximately 15-kDa protein that completely blocks the adhesion of platelets to collagen-coated microtiter plates with an IC50 of 8 nM. In the same concentration range it does not inhibit collagen-induced platelet aggregation or platelet adhesion to fibrinogen and has a partial inhibitory effect on platelet adhesion to fibronectin. TAI also blocks the adhesion of human endothelial cells to collagen, thus its inhibitory effect is not limited to platelets. TAI competes for the binding to platelets of a radiolabeled monoclonal antibody against the platelet glycoprotein Ia-IIa integrin complex. Based on its selective activity and small size, TAI is a promising new molecule for exploring cell-collagen interactions.
...
PMID:An inhibitor from the argasid tick Ornithodoros moubata of cell adhesion to collagen. 769 4

Twelve different human primary and metastatic Ewing's sarcoma (ES) and primitive peripheral neuroectodermal tumour (pPNET) cell lines were examined by fluorocytometric analysis for the expression of alpha 1, alpha 2, alpha 3 and alpha 6 very late antigen (VLA) beta 1-integrins. VLA-alpha 1, was abundantly expressed on all typical ES cell lines and pPNET cell lines, while absent from atypical (large cell) ES cells. VLA-alpha 2 was displayed on some ES and pPNET cell lines. In two different pPNET cell lines, derived from the same patient, VLA-alpha 2 expression was considerably higher on primary cells compared with metastatic cells. VLA-alpha 3 was exclusively expressed on pPNET cell lines. Expression of VLA-alpha 6 was higher on metastatic than on primary ES and pPNET cells. Adhesion assays on purified extracellular matrix (ECM) proteins, using monospecific adhesion-blocking antibodies, disclosed VLA-1 (alpha 1 beta 1) on typical ES cells and pPNET cells, and VLA-2 (alpha 2 beta 1) on atypical ES cells, as dual collagen type IV (COIV)/laminin (LM) binding sites, and VLA-6 (alpha 6 beta 1) as a specific LM binding site. Treatment of typical ES cells and pPNET cells for up to 48 h with recombinant human interferon-gamma (rhIFN gamma) and tumour necrosis factor-alpha (rhTNF alpha) upregulated alpha 1 and beta 1 expression, concomitant with an increase in cell adhesion to COIV and LM. Alternatively, these cytokines downregulated the expression of alpha 2, alpha 6 and beta 1 on atypical ES cells, concomitant with a decrease in the adhesion to COIV and LM. In conclusion, these findings suggest that the difference in repertory of CO and LM integrin receptors on ES cells and pPNET cells reflects tumour status and degree of differentiation. Furthermore, our data indicate that IFN gamma- and TNF alpha-mediated alteration in the level of expression of distinct VLAs on ES and pPNET cells is correlated with changes in the adhesive behaviour of these tumour cells.
...
PMID:Expression of functional very late antigen-alpha 1, -alpha 2, -alpha 3 and -alpha 6 integrins on Ewing's sarcoma and primitive peripheral neuroectodermal tumour cells and modulation by interferon-gamma and tumour necrosis factor-alpha. 785 12

Adhesion molecules are involved in the recruitment of leucocytes to sites of inflammation. In this study, we determined the expression of several adhesion molecules on isolated human alveolar type II pneumonocytes. Type II pneumocytes were isolated from 10 normal lung specimens, by enzymatic digestion with dispase, followed by metrizamide gradient centrifugation and panning on immunoglobulin G (IgG)-coated plastic dishes. With the freshly isolated type II cells, immunostaining was performed using a sensitive immunoperoxidase slide technique. In all cases, 60-90% of type II cells were positive for intercellular adhesion molecule-1 (ICAM-1) (CD54). A minor portion of type II cells expressed the alpha 4 (CD49d) subunit of the beta 1-integrins, and the alpha-v (CD51) subunit of the vitronectin receptor. CD11a, CD11b, CD11c, CD18, CD49b, and CD49f failed to demonstrate any immunostaining with type II cells. In conclusion, the observation of the expression of ICAM-1 and, to a lesser degree, of some integrin subunits, may indicate that alveolar type II cells participate in local immune and inflammatory responses.
...
PMID:ICAM-1 and integrin expression on isolated human alveolar type II pneumocytes. 791 65

1 2 Next >>