Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leukotriene B4 (LTB4) induced an in vitro transient state of hyperadhesiveness in cultured human umbilical vein endothelial cells (HUVEC), leading to a 2.2-fold increase in the binding of neutrophil granulocytes (PMN), which was less than that conferred by platelet activating factor (PAF) though more than thrombin did (3.4- or 2.0-fold increases, respectively). This study concerns the role of the adhesive molecules CD18 and CD54 for the LTB4- (as well as thrombin- and PAF-) induced endothelial hyperadhesiveness. The MoAbs 60.3 (to the CD18 molecule on PMN) and 84H10 (to one epitope of CD54 on the HUVEC) blocked the adherence of PMN to LTB4-treated HUVEC, whereas MoAb LB-2 (directed at another CD54 epitope) failed to do so. MoAb 84H10 blocked 43% of the thrombin-induced hyperadhesiveness, whereas the PAF response was unaffected. Thus, LTB4-induced HUVEC hyperadhesiveness may therefore be related to a specific domain on the CD54 (or on an antigenically related molecule) as well as being dependent on CD18, whereas the involvement of CD54 was much less or non-existent for the thrombin and PAF responses, respectively.
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PMID:Leukotriene B4-induced hyperadhesiveness of endothelial cells for neutrophils: relation to CD54. 135 91

Human umbilical vein endothelial cells were transfected by electroporation with the plasmid pSV3neo, containing the early region of simian virus 40. The resultant "cell lines" divide rapidly (population doubling time of 33 h) for up to 24 passages in medium supplemented with 5% (v/v) serum and 2.5 micrograms/ml endothelial cell growth supplement. Several of these lines express basal levels of ICAM-1 and MHC class I but not MHC class II. One cell line, designated SGHEC-7, retained a number of differentiated endothelial cell functions throughout its lifespan. These functions include increased production of tissue plasminogen activator in response to histamine, thrombin, and PMA. Stability of function and rapid growth over 24 passages endow these cells with a number of advantages over primary cultures. The homogeneous cell population and consistency of response make them ideal for biochemical and immunological studies hereto impractical with primary human endothelial cells. The success of this approach may allow the production of functional cell lines from other vascular beds.
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PMID:Characterization of human umbilical vein endothelial cell lines produced by transfection with the early region of SV40. 137 94

Thrombin-induced expression of endothelial adhesivity toward neutrophils (PMN) was studied using human umbilical vein endothelial cells (HUVEC). HUVEC were challenged with human alpha-thrombin for varying durations up to 120 min, after which the cells were fixed with 1% paraformaldehyde and 51Cr-labeled human PMN were added to determine PMN adhesion. Endothelial adhesivity increased within 15 min after alpha-thrombin exposure, and the response persisted up to 120 min. Expression of endothelial adhesion proteins, P-selectin (GMP-140, PADGEM, CD62), and intercellular adhesion molecule-1 (ICAM-1; CD54) on the endothelial surface was quantitated by increase in the specific binding of anti-P-selectin mAb G1 and anti-ICAM-1 mAb RR1/1 labeled with 125I. P-selectin expression was maximal at 5-15 min alpha-thrombin exposure and decayed to basal levels within 90 min. In contrast, ICAM-1 activity increased at 30 min and remained elevated for 120 min after alpha-thrombin challenge. The initial endothelial adhesivity was dependent on P-selectin expression since PMN adhesion occurring within the first 30 min after alpha-thrombin challenge was inhibited by mAb G1. The later prolonged PMN adhesion was ICAM-1 dependent since this response was inhibited by mAb RR1/1 and to the same degree by the anti-CD18 mAb IB4. Anti-ELAM-1 mAb BB11 had no effect on adhesion of PMN to the alpha-thrombin-challenged cells. The initial P-selectin expression and PMN adhesion responses were reproduced by the 14-amino peptide (SFLLRNPNDKYEPF) (thrombin-receptor activity peptide; TRP-14) which comprised the NH2 terminus created by thrombin's proteolytic action on its receptors. However, TRP-14-induced PMN adhesion was transient, and TRP-14 did not cause ICAM-1 expression. The ICAM-1-dependent PMN adhesion mediated by alpha-thrombin was protein synthesis independent since ICAM-1 expression and PMN adhesion were not inhibited by cycloheximide pretreatment of HUVEC. Moreover, Northern blot analysis indicated absence of ICAM-1 mRNA signal up to 180 min after alpha-thrombin challenge. In conclusion, thrombin-induced endothelial adhesivity involves early- and late-phase responses. The initial reversible PMN adhesion is mediated by rapid P-selectin expression via TRP-14 generation. Thrombin-induced PMN adhesion is stabilized by a protein synthesis-independent upregulation of the constitutive ICAM-1 activity which enables the interaction of ICAM-1 with the CD18 beta 2 integrin on PMN.
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PMID:Thrombin-induced expression of endothelial P-selectin and intercellular adhesion molecule-1: a mechanism for stabilizing neutrophil adhesion. 138 47

Monoclonal antibody H3/5-47 was raised against a human melanoma metastasis and recognizes an antigen expressed in the endothelial cells of all normal human organs as assessed by immunohistochemistry. Antigen expression is higher in venous than in capillary or arterial endothelia; capillary endothelia of different microvascular beds, such as skin, lung, gut or liver, may express varying amounts of this antigen. H3/5-47 antigen expression in the endothelia of diseased tissues (inflammatory diseases, neoplasias) largely reflects its expression pattern in normal tissues. As might be anticipated, the highest expression of H3/5-47 antigen is found in resting adult cutaneous and hepatic cavernous venous hemangiomas. In contrast, psoriatic vessels, characterized by hypertrophy and fenestrations, tend to express H3/5-47 antigen at a much lower density. In human umbilical vein endothelial cells, half the single donor cases show no expression of H3/5-47 antigen, while the rest express the antigen at relatively low densities in about half the cells. Treatment with interferon-gamma or thrombin, but not interleukin-1, lipopolysaccharide, endothelial cell growth factor or phorbolester, either enhances or induces de novo expression in cultured human umbilical vein endothelial cells within 24h; maximum expression of H3/5-47 antigen is induced by interferon-gamma within 72 h. H3/5-47 antigen is not similar to other antigens inducible in human umbilical vein endothelial cells such as HLA-DR, ICAM-1, HECA-452, Leu13, MCP-1 or gamma-IP-10. It is not specifically expressed in the endothelium as it may also recognize certain epithelia, peripheral nervous tissue and bone marrow-derived cell populations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Monoclonal antibody H3/5-47 recognizes an inducible cell surface antigen expressed differently in endothelium of normal and diseased tissues and in vitro. 162 58

Current evidence indicates that the localization and extravasation of neutrophils is a complex process involving several adhesion molecules with apparently distinct functions, and a highly coordinated and dynamic interplay between the neutrophil and the endothelial cell that is influenced by the shear forces present at the interface between these two cell types. Chemotactic stimulation of the neutrophil not only induces directed locomotion but markedly alters the surface expression and functions of the neutrophil adhesion molecules, having both an upregulating and downregulating influence. Cytokines such as interleukin 1 induce the synthesis and surface expression of endothelial adhesion molecules such as ICAM-1 and ELAM-1, and stimuli such as thrombin and histamine induce the rapid mobilization to the endothelial surface of another adhesion molecule, GMP-140. Transendothelial migration of neutrophils in most settings both in vitro and in vivo appears to require CD18 integrins on the neutrophil and ICAM-1 on the endothelial cells. This is most clearly demonstrated by the genetic deficiency of CD18 in humans, dogs and cattle, where neutrophil extravasation at most inflammatory sites is almost completely absent. Though the coordinated functions of the various neutrophil and endothelial adhesion molecules are highly efficient in promoting neutrophil extravasation, there has been relatively little investigation of their utilization in tumor cell dissemination. Recent results indicate that such studies may prove fruitful. For example, some adenocarcinoma cell lines express the complex carbohydrate (sialyl Lewis x) recently shown to be a ligand for ELAM-1.
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PMID:PMN adhesion and extravasation as a paradigm for tumor cell dissemination. 191 73

We compared the effects of phorbol 12-myristate 13-acetate (PMA) and thrombin with those of nonlytic concentrations of reactive oxygen species (ROS) generated by hypoxanthine (HX)-xanthine oxidase (XO) on the adhesion properties of human umbilical cord vein endothelial cells (HUVEC) to resting polymorphonuclear neutrophils (PMN). PMN adherence to HX-XO-treated HUVEC was increased approximately twofold to 2.5-fold relative to untreated HUVEC, both immediately and after 2 hours. It was not additive to that induced by PMA or thrombin stimulation of HUVEC. ROS-induced adherence was not due to platelet-activating factor (PAF) or P-selectin expression, as it was neither antagonized by BN52021 (PAF receptor antagonist) nor inhibited by anti-P-selectin monoclonal antibody (MoAb), contrary to the increased adhesion of PMA- and thrombin-stimulated HUVEC. PMN preincubated with mannose-6-P or N-acetylneuraminic acid (sialic acid), but not mannose or galactose-6-P, showed reduced adherence to ROS-treated HUVEC, suggesting that carbohydrate molecules were expressed on the latter and served as the ligand for the PMN L-selectin. Intercellular adhesion molecule (ICAM-1), constitutively present on the surface of resting HUVEC, was involved in the PMN adherence to ROS-treated HUVEC, since this adherence was inhibited by anti-ICAM-1, anti-CD11a, anti-CD11b, and anti-CD18 MoAbs. A non-CD18, non-ICAM-1-dependent mechanism is also involved in this adherence, since effects of these MoAbs were not additive; moreover, combinations of anti-CD18 and anti-ICAM-1 MoAbs with mannose-6-P and sialic acid completely inhibited PMN adherence. The increased binding of PMN to HX-XO-exposed HUVEC observed here involved IC-AM-1, but was independent of its upregulation, and another non-ICAM-1-dependent mechanism, in which carbohydrates expressed on HUVEC recognize L-selectin on PMN.
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PMID:Reactive oxygen species rapidly increase endothelial ICAM-1 ability to bind neutrophils without detectable upregulation. 751 10

We have demonstrated that the endothelial cell-derived superoxide anion is deeply involved in the endothelial cell injury induced by activated neutrophils (Fujita, H., Morita, I. and Murota, S. (1994) Arch. Biochem. Biophys. 309, 62-69). To clarify the mechanism underlying the increase in the endothelial cell-derived superoxide anion induced by activated neutrophils, the conversion of xanthine dehydrogenase (XD) to xanthine oxidase (XO) in cultured endothelial cells isolated from bovine carotid arteries was investigated. Although the endothelial cells expressed both XD and XO activity, the XO activity of unstimulated cells comprised about 12% of the total (XD + XO) activity. When endothelial cells were exposed to neutrophils activated with phorbol 12-myristate 13-acetate (PMA), XO activity rapidly increased about 3-fold over the control. Whereas treatment of endothelial cells with PMA alone or unstimulated neutrophils alone did not increase the XO activity at all. The increase in XO activity in endothelial cells was also observed on the treatment of the cells with neutrophils activated with leukotriene B4 or thrombin. To determine whether or not proteases released from activated neutrophils are involved in the increased conversion of XD to XO in endothelial cells, the effects of the elastase specific inhibitor, ONO-5046, and protease inhibitors, such as aprotinin, gabexate mesylate and urinastatin, were examined. However, these protease inhibitors did not suppress the conversion of XD to XO induced by PMA-activated neutrophils. Moreover, the treatment of endothelial cells with purified human neutrophil elastase and H2O2 also did not affect the conversion at all. In contrast, monoclonal antibodies against CD11a and CD18 significantly inhibited the increased conversion of XD to XO induced by PMA-activated neutrophils. Moreover, tyrosine kinase inhibitors such as staurosporin and herbimysine also inhibited the increased conversion of XD to XO induced by PMA-activated neutrophils. These results indicate that the adhesion of activated neutrophils to endothelial cells via CD11a/CD18-ICAM-1 is involved in the conversion of XD to XO in endothelial cells induced by activated neutrophils.
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PMID:Conversion of xanthine dehydrogenase to xanthine oxidase in bovine carotid artery endothelial cells induced by activated neutrophils: involvement of adhesion molecules. 769 38

Intercellular adhesion molecule-1 (ICAM-1) is an antigen that is strongly expressed by vascular endothelial cells at sites of local inflammation and participates in the development of inflammation. In the present study, vascular endothelial cells were stimulated by inflammatory cytokines that promote thromboxane A2 synthesis to observe their effects on the expression and shedding of ICAM-1 on the cell surface. In addition, the suppressive effects of DP-1904 ([+/-]-6-[1-imidazolylmethyl]-5,6,7,8-tetrahydronaphthalene-2- carboxylic acid hydrochloride hemihydrate), a thromboxane A2 synthesis inhibitor, on ICAM-1 expression were evaluated. ICAM-1 expression on the surface of human umbilical vein endothelial cells was increased significantly by stimulation with interleukin-1 beta, tumor necrosis factor alpha (TNF alpha), thrombin and platelet-activating factor (PAF). DP-1904, an inhibitor of thromboxane A2 synthesis, significantly suppressed the expression of ICAM-1 on the surface of human vascular endothelial cells that had been stimulated by TNF alpha or PAF. These findings suggest that an enhanced expression of thromboxane A2 on human vascular endothelial cells is closely related to the expression of ICAM-1 on the surface of these cells.
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PMID:DP-1904, a specific inhibitor of thromboxane A2 synthesizing enzyme, suppresses ICAM-1 expression by stimulated vascular endothelial cells. 781 62

Primary human vascular endothelial cells were immortalized by the integration of a single DNA copy of an amphotrophic, replication-deficient retrovirus containing the E6/E7 genes of human papilloma virus. To date, the resulting cell lines, designated EC-RF7 and EC-RF24, have been cultured for more than 1 year. The cell lines have retained a diploid karyotype, display no abnormalities, and are able to grow in a polar mode. Analysis of the EC-RF cell lines by indirect immunofluorescence, using an extensive panel of monoclonal antibodies, showed expression of endothelial cell-specific soluble (von Willebrand factor) and surface-bound antigens (endoglin, PCAM-1) indistinguishable from that of primary cells. In addition, the expression of the markers CD9, 13, 14, 29, 36, 40, 51, and 55 that are not restricted to endothelial cells was also similar for the immortalized and the primary endothelial cells. Immortalization did not alter the expression of the surface adhesion molecules E-selectin, VCAM-1, and ICAM-1 nor transmigration of neutrophils. The regulation of extracellular proteolytic activity by EC-RF24 was established by measuring both the induction of functional tissue factor (promotion of Factor Xa generation) and the functional deposition of plasminogen activator inhibitor 1 in the subendothelial matrix (SDS-resistant complex formation with thrombin). Finally, the biosynthesis of the endothelial cell-specific von Willebrand factor was studied in detail in the EC-RF24 cell line and the results were compared with those of primary endothelial cells.
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PMID:Maintenance of vascular endothelial cell-specific properties after immortalization with an amphotrophic replication-deficient retrovirus containing human papilloma virus 16 E6/E7 DNA. 781 21

Endothelial damage, synovial oedema, fibrin deposition, polymorphonuclear cell (PMN) invasion, and mild lining cell hyperplasia characterize acute inflammatory arthritis. Later on, perivascular tissue is infiltrated by mononuclear cells. The early events are mediated by interactions between PMNs and endothelial cells. Both parts in the adhesion event are activated with multiple stimuli resulting in complex interactions of varying intensity and duration. Adhesion molecules present on the surface of PMNs (L-selectin) or induced by inflammatory stimuli (beta 2-integrins) mediate PMN adhesion to activated endothelium, which has counter receptors (E-selectin for L-selectin and ICAM-1 and ICAM-2 for beta 2-integrins). At the initial phase L-selectin initiates the rolling of PMNs on endothelial cells. Further stimuli result in a more prolonged adhesion between PMNs and endothelium. At the side of endothelium, induction of P-selectin and PAF by histamine, thrombin and LTC4 contribute to the acute rolling of PMNs on endothelial surface. Tumor necrosis factor (TNF), interleukin-1 (IL-1) and lipopolysaccharide activate endothelial cells to synthesize interleukin-8 (IL-8), a potent chemotactic and proadhesive mediator for PMNs, and further adhesion molecule (E-selectin), a mediator of long-term adhesion between PMN and endothelium. After adhesion and migration to the focus of inflammation, PMNs induce inflammation by aggregating, releasing hydrolyzing enzymes, generating lipid peroxidation products such as prostaglandins and LTB4, and oxygen derived free radicals. In studies on the pathogenesis of seronegative spondyloarthropathies, we have shown persistently aberrant PMN function evidenced by enhanced chemotaxis and high production of toxic oxygen derived free radicals by PMN.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The present knowledge of the inflammatory process and the inflammatory mediators. 781 74


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