Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The fate of E-selectin expressed on TNF-activated monolayers of HUVEC was investigated by confocal laser scanning microscopy. Cytokine-activated endothelial cells internalized mAb to E-selectin in a very rapid, energy-dependent fashion. By contrast, mAb against ICAM-1 and VCAM-1 remained surface bound. The E-selectin mAb was recovered in intracellular compartments with a tubular morphology, some of which appeared to be interconnected. Cathepsin B, a ubiquitously expressed lysosomal protease, was found to co-localize in these structures. Functional specificity of E-selectin-internalization was observed upon addition of the fluorescent SLex-oligosaccharide to the activated HUVEC monolayers. Uptake into the same E-selectin-positive compartments was observed, whereas the control oligosaccharide Lex was not internalized at all. The process of internalization was found to be unaffected by most inhibitors of protein kinase C, cAMP-dependent PKA, or protein tyrosine kinase activity. Whereas cytochalasin B preincubation of HUVEC failed to inhibit the internalization process, colchicine and vinblastine, reagents that interfere with the metabolism of tubulin, prevented the formation of the elongated structures in which E-selectin would normally be internalized. Concomitantly, the expression of E-selectin at the cell surface was significantly increased.
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PMID:Cytokine-activated endothelial cells internalize E-selectin into a lysosomal compartment of vesiculotubular shape. A tubulin-driven process. 751 27

Cytokine stimulation of human umbilical vein endothelial cells (HUVE) induces surface expression of the adhesion molecules vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and endothelial leukocyte adhesion molecule-1 (E-selectin). We previously found that induction of adhesion molecule expression in HUVE is regulated, at least in part, by protein kinase C (PKC) activation, although this is not associated with the expected translocation of PKC from the cytosolic to the particulate fraction. We therefore investigated potential nuclear targets for PKC. Topoisomerase II is localized to the nuclear matrix and has been shown to be phosphorylated, both in vitro and in vivo, by PKC. In HUVE, the topoisomerase II selective inhibitors novobiocin, nalidixic acid, and etoposide prevented cytokine-induced VCAM-1 surface expression, but not E-selectin or ICAM-1 surface expression. Similarly, novobiocin and nalidixic acid reduced the accumulation of VCAM-1 mRNA in response to tumor necrosis factor-alpha treatment of HUVE. The inhibitory effect of the topoisomerase II inhibitors on VCAM-1 expression was not due to non-specific toxicity, as protein synthesis, measured by trichloroacetic acid precipitation of 35S-methionine labeled proteins, and transcription, determined by beta-actin mRNA levels, were not decreased. In contrast to the observed reduction of VCAM-1 mRNA accumulation and surface protein expression, inhibition of topoisomerase II activity enhanced E-selectin mRNA accumulation and surface protein expression in response to tumor necrosis factor-alpha stimulation of HUVE. This work demonstrates that topoisomerase II activity may differentially regulate the expression of adhesion molecules on HUVE.
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PMID:Inhibitors of topoisomerase II prevent cytokine-induced expression of vascular cell adhesion molecule-1, while augmenting the expression of endothelial leukocyte adhesion molecule-1 on human umbilical vein endothelial cells. 752 51

Infections with verocytotoxin (VT) producing Escherichia coli have been strongly implicated in the epidemic form of hemolytic uremic syndrome (HUS). Endothelial damage plays a central role in the pathogenesis of HUS. In vitro studies have shown that VT can damage endothelial cells after interaction with its cellular receptor globotriaosylceramide (GbOse3cer). Cytokines, such as tumor necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) can potentiate the toxic effect of VT by inducing a protein-synthesis dependent increase in VT receptors on endothelial cells. In this study, the mechanisms underlying the increase in endothelial VT receptors induced by TNF alpha were studied in more detail. To investigate which proteins were involved in this induction, endothelial cells were incubated with and without TNF alpha in the presence of 14C-galactose or 14C-glucose. Thin-layer chromatography (TLC) analysis of the glycolipid extracts of these cells demonstrated a markedly enhanced incorporation of 14C-galactose in GbOse3cer and other galactose-containing glycolipids, suggesting that TNF alpha enhanced galactosyl-transferase activity. To examine the role of the two recently cloned TNF-receptors (TNFR-p75 and TNFR-p55) in the TNF alpha-induced increase in GbOse3cer in human endothelial cells, cells were incubated with TNF alpha, the TNFR-p55 selective R32W-S86T-TNF alpha-mutant, or the TNFR-p75 selective D143N-A145R-TNF alpha-mutant. The effect of TNF alpha activation, determined by binding-experiments with 125I-VT-1, could be largely, but not completely mimicked by R32W-S86T-TNF alpha. Although incubation of cells with D143N-A145R-TNF alpha did not show an increase in VT-1 binding, the monoclonal antibody utr-1, which prevents binding to TNFR-p75, decreased the TNF alpha-induced VT-1 binding. Activation of protein kinase C (PKC) by phorbol ester increases the expression of VT-1 receptors; this effect was prevented by the PKC inhibitor Ro31-8220 and by homologous desensitization by pretreatment with phorbol ester. In contrast, the presence of the protein kinase inhibitor Ro31-8220 or desensitization of PKC activity reduced the TNF alpha-induced increase in VT-1 receptors maximally by 50% and 24%, respectively. Comparable reductions in overall protein synthesis and the synthesis of E-selectin and plasminogen activator inhibitor-1 (PAI-1) were observed. This suggests an effect on general protein synthesis rather than a specific effect of PKC in the signal transduction pathway, by which TNF alpha induces VT-1 receptors. Our results indicate that TNF alpha can increase the VT-1 receptors on endothelial cells by inducing galactosyl-transferase activity, that this action of TNF alpha mainly occurs via the TNFR-p55; and that PKC activation increases expression of VT-1 receptors by a separate mechanism that acts additively to the TNF alpha-induced increase in VT-1 receptors.
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PMID:Tumor necrosis factor alpha induces endothelial galactosyl transferase activity and verocytotoxin receptors. Role of specific tumor necrosis factor receptors and protein kinase C. 753 May 4

Leukocyte adhesion to kidney cells is an early event in renal inflammation, such as glomerulonephritis. We developed an experimental model of monocyte adhesion to cultured human mesangial cells. U-937 myelomonocytic leukaemia cells, similar to peripheral blood human monocytes, irreversibly bound to mesangial cell monolayers upon 30-180 min coincubations (to a max. of 13,600 +/- 1100/cm2 monolayer), as assessed by cell counting, U-937 labelling with 3H-thymidine, and colorimetry of nuclear staining with crystal violet. Adhesion was enhanced in mesangial cells proliferating in response to 17% fetal bovine serum, indicating expression of a proinflammatory phenotype. E. coli lipopolysaccharide (LPS), tumour necrosis factor-alpha (TNF-alpha) and protein kinase C activation with phorbol myristate acetate (PMA) potentiated monocyte binding during either coincubation or 24-h pretreatment (0.1 microM PMA, +200 +/- 21%). Binding was also promoted by pretreatment with vasoconstrictors, such as the thromboxane A2 mimetic, U-46619 (10 nM-1 microM, max. +35 +/- 3%), or 1 microM angiotensin II (+64 +/- 4%). To elucidate the mechanisms of monocyte adhesion, we analysed the adhesion molecules expressed by human mesangial cells, employing reverse transcription/polymerase chain reaction to detect ICAM-1, VCAM-1 and E-selectin gene expression. Proliferating cells express VCAM-1 and ICAM-1, confirmed by immunocytochemical staining and 79 +/- 3% inhibition of stimulated adhesion by pretreatment of mesangial cells with an anti-ICAM-1 monoclonal Ab. E-selectin transcription was not detectable.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of U-937 monocyte adhesion to cultured human mesangial cells by cytokines and vasoactive agents. 754 54

Monocyte adherence to the endothelium, their penetration to the subendothelial space and excessive lipid accumulation (foam cell formation) are the initial events in atherogenesis. Scavenger receptors have been reported to play an important role in foam cell formation, since modified low density lipoproteins can be taken up via scavenger receptors in a non-down-regulated fashion. In this study we demonstrate that stimulation of scavenger receptors in endothelial cells induces the expression of endothelial adhesion molecules. Polyinosinic acid (poly I), a known scavenger receptor ligand, significantly induced the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin on human umbilical vein endothelial cells when compared with polycytidylic acid (poly C), a structurally related compound to poly I, which does not bind to the scavenger receptor. The effect of scavenger receptor ligands on the endothelial cell line EA hy. 926 was also tested. Poly I up-regulated ICAM-1 expression also on EA hy. 926 cells, while it had no effect on IL-1 beta or tumour necrosis factor-alpha (TNF-alpha) production on the same cell line. Poly I-induced ICAM-1 expression on EA hy. 926 cells could be inhibited by H7, a protein kinase C inhibitor, while HA 1004, a preferential protein kinase A inhibitor, had no effect on ICAM-1 expression. The role of protein kinase C in scavenger receptor-mediated adhesion molecule upregulation was confirmed by the ability of poly I to directly activate protein kinase C, when measured with 3H-phorbol dibutyrate binding to EA hy. 926 cells, while poly C again was ineffective.
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PMID:Regulation of endothelial adhesion molecules by ligands binding to the scavenger receptor. 768 91

Intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (ELAM-1, E-selectin) are endothelial surface molecules that play a role for leukocyte recruitment to sites of inflammation, e.g., during contact hypersensitivity. We studied the effects of sensitizing agents (2,4-dinitro-benzenesulfonic acid, metal salt haptens) and chemically related substances on endothelial adhesion molecule expression. Using flow cytometry and an enzyme-linked immunosorbent assay, NiCl2 and, to a lesser extent, CoCl2 were found to up-regulate ICAM-1, VCAM-1, and ELAM-1 expression on cultured human umbilical vein endothelium whereas the other substances tested showed no effects. Induction of adhesion molecules by NiCl2 required de novo mRNA and protein synthesis. Up-regulation could be blocked by kinase inhibitor H-7 but not staurosporine, suggesting involvement of phosphorylation events independent of protein kinase C activation. Concomitant application of NiCl2 and neutralizing antibodies to IL-1 did not block up-regulation by the hapten demonstrating that the latter did not act via an IL-1-dependent autocrine mechanism. Regarding ELAM-1 induction, pre-treatment for 24 h with NiCl2 produced hyporesponsiveness to IL-1 and TNF-alpha upon restimulation, suggesting that NiCl2 and these cytokines may partially share a common pathway of activation. In addition, analysis of cultured foreskin specimens revealed that NiCl2 may induce up-regulation of ELAM-1 on microvascular endothelium in vivo. Our data demonstrate that both Ni++ and Co++ to which simultaneous contact sensitivity is frequently observed have the ability to directly up-regulate endothelial adhesion molecules. This shared property may represent an adjuvant mechanism that promotes sensitization and elicitation events in contact hypersensitivity to these haptens.
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PMID:Nickel chloride and cobalt chloride, two common contact sensitizers, directly induce expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule (ELAM-1) by endothelial cells. 768 25

A protein kinase C (PKC) agonist selective for the beta I isozyme, 12-deoxyphorbol 13-phenylacetate 20-acetate (dPPA), induced NF-kappa B-like binding activity and surface expression of E-selectin and VCAM-1 in human umbilical vein endothelial cells (HUVEC), similar to the effects of tumor necrosis factor-alpha (TNF-alpha). Induction of E-selectin and VCAM-1 expression by dPPA was completely inhibited by the PKC inhibitors staurosporine and Ro31-7549. The PKC inhibitors also reduce TNF-alpha-induced VCAM-1 expression. However, neither dPPA nor TNF-alpha translocated PKC from the cytosolic to the plasma or nuclear membrane particulate fractions in HUVEC. These results indicate that activation of the beta I PKC isozyme is sufficient for expression of E-selectin and VCAM-1, and suggest that PKC may mediate the effects of TNF-alpha and dPPA without requiring the translocation normally associated with activation of PKC.
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PMID:A protein kinase C agonist, selective for the beta I isozyme, induces E-selectin and VCAM-1 expression on HUVEC but does not translocate PKC. 768 53

We investigated whether lipoteichoic acid (LTA) induces the expression of E-selectin and neutrophil adhesion to human umbilical vein endothelial cells (HUVECs). LTA (0.01-30 micrograms/ml) induced the expression of E-selectin in a concentration-dependent manner with maximal response at 10 micrograms/ml. The expression level of E-selectin increased from 2 h after stimulation by LTA with the maximal level at 4-8 h. Neutrophil adhesion to LTA-treated HUVECs correlated with the levels of E-selectin expression. In addition, the adhesion was clearly inhibited by anti-human E-selectin monoclonal antibody CY-1787 as well as a sialyl Lewis X (SLeX) oligosaccharide. LTA-induced expression of E-selectin was inhibited by protein kinase C inhibitors, H-7 and staurosporine. These results indicate that LTA induced the expression of E-selectin and neutrophils adhered to HUVECs via E-selectin.
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PMID:Lipoteichoic acid-induced neutrophil adhesion via E-selectin to human umbilical vein endothelial cells (HUVECs). 855 78

Interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha) induce tissue factor in endothelium, which results in activation of the coagulation cascade. Despite extensive investigation, in which various stimuli that induce tissue factor have been defined, the intracellular processes that control tissue factor expression are not well understood. It has been proposed that protein kinase C regulates tissue factor expression primarily because phorbol myristate acetate, the protein kinase C activator, induces tissue factor expression. In this study we examined whether IL-1 alpha- or TNF-alpha-stimulated tissue factor production is regulated through a protein kinase C-dependent mechanism. Northern blot analysis showed that cytokine-induced tissue factor mRNA was significantly reduced in human umbilical vein endothelial cells treated with calphostin C, a specific protein kinase C inhibitor. Tissue factor functional activity was decreased in the presence of calphostin C as well. Calphostin C also inhibited phorbol myristate acetate-induced tissue factor expression. In contrast, calphostin C did not alter cytokine induction of E-selectin or prostacyclin release. Because calcium stimulates protein kinase C binding to the membrane and its resulting catalytic activity, human umbilical vein endothelial cells were exposed to IL-1 alpha or TNF-alpha in the presence of calcium ionophore A23187. A23187 had little effect alone but significantly augmented cytokine stimulation of tissue factor mRNA. Okadaic acid, a phosphatase inhibitor, increased cytokine-induced tissue factor mRNA compared with cytokine alone, which suggests that a phosphorylation event is important in tissue factor expression. These results indicate that protein kinase C is involved in cytokine activation of endothelial cell tissue factor expression.
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PMID:Protein kinase C regulates cytokine-induced tissue factor transcription and procoagulant activity in human endothelial cells. 859

Induction of endothelial adhesion molecules by the cytokine tumor necrosis factor-alpha (TNF) can occur independently of protein kinase C and activation of a protein tyrosine kinase (PTK) has recently been implicated in the upregulation of vascular cell adhesion molecule 1 (VCAM-1) by interleukin-4 (IL-4) on endothelial cells. We demonstrate that the PTK inhibitors herbimycin A or genistein suppress induction of endothelial VCAM-1 and E-selectin, as well as subsequent monocytic cell adhesion to endothelial cells stimulated by TNF. Inhibition studies indicate that specific tyrosine phosphorylation following PTK activation is involved in the mobilization of the transcription factor, nuclear factor kappa B, and VCAM-1 mRNA expression. This may have implications for pathophysiological conditions that involve the upregulation of these molecules (e.g. inflammation and atherosclerosis).
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PMID:Involvement of tyrosine phosphorylation in endothelial adhesion molecule induction. 873 63


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