Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have established a novel human megakaryoblastic cell line, designated as MEG-A2, from a patient with megakaryoblastic crisis of Philadelphia (Ph) chromosome positive chronic myelogenous leukemia. MEG-A2 cells showed positive phenotypes for periodic acid Schiff and alpha-naphthylbutyrate esterase reactions, but were negative for myeloperoxidase and naphthol ASD chloroacetate esterase reactions. Flow cytometric analyses of cell surface markers revealed that MEG-A2 cells had a low level of GP IIb/IIIa expression as well as apparent expressions of CD4, CD7, CD13, CD33 and CD34 antigens, but no expression of GP Ib nor glycophorin A. Stimulation with phorbol 12-myristate 13-acetate (PMA) dramatically increased the expression of megakaryocyte-related markers such as HPL-3, J15, Pit-1, Y2/51 and AN51 in MEG-A2 cells. The PMA-stimulation also induced expression of platelet peroxidase (PPO) in MEG-A2 cells on electromicroscopic observation. Proliferative responses to granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) or erythropoietin were observed, and the expression of GP IIb/IIIa was increased by stimulation with GM-CSF, IL-3, erythropoietin and interleukin-6 (IL-6). Protein S mRNA expression was seen in cultured cells on Northern blot analysis. Expression of platelet factor 4 mRNA was induced in PMA-stimulated cells, and a marked accumulation of protein was observed in the culture medium. In conclusion, a new cell line, MEG-A2, belongs to the relatively immature megakaryocytic lineage and has markedly increased megakaryocytic characteristics with PMA stimulation.
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PMID:Establishment and characterization of an immature human megakaryoblastic cell line, MEG-A2. 786 73

We investigated the effect of inflammatory cytokines on the intercellular adhesion molecule-1 expression on primary cultured murine hepatocytes. Tumor necrosis factor-alpha, interferon-gamma and interleukin-1 alpha up-regulated the intercellular adhesion molecule-1 expression on hepatocytes in a dose-dependent fashion; however, interleukin-6 did not. On the basis of kinetic analysis, the expression level reached a peak 24 hr after stimulation, and both cycloheximide and actinomycin D inhibited the expression. Furthermore, T lymphocytes bind more to interferon-gamma-stimulated hepatocytes than to unstimulated hepatocytes. The binding was dependent on the concentration of interferon-gamma. The binding was also up-regulated by stimulating T lymphocytes with phorbol myristate acetate. Tumor necrosis factor-alpha and interleukin-1 alpha demonstrated the same effect as interferon-gamma, whereas interleukin-6 did not increase T-lymphocyte adhesion to the hepatocytes. The adhesion induced by interferon-gamma or tumor necrosis factor-alpha was inhibited by antibody against either intercellular adhesion molecule-1 or lymphocyte function-associated antigen-1, a ligand for intercellular adhesion molecule-1, but was not inhibited by CD44 antibodies. These results demonstrate that inflammatory lymphokines enhance the T-lymphocyte adhesion to primary cultured hepatocytes by up-regulating the intercellular adhesion molecule-1 expression on the stimulated hepatocytes by activating the de novo pathway. This mechanism may play an important role in the pathogenesis of hepatitis.
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PMID:Inflammatory cytokines up-regulate intercellular adhesion molecule-1 expression on primary cultured mouse hepatocytes and T-lymphocyte adhesion. 790 80

Intercellular adhesion molecule-1 (ICAM-1) is a transmembrane glycoprotein that promotes adhesion in immunological and inflammatory reactions. ICAM-1 is expressed on cells of many lineages and is induced by interleukin-6 (IL-6) and interferon-gamma (IFN-gamma). Functional analysis of ICAM-1 promoter-luciferase constructs in HepG2 cells enabled us to identify a region between -110 and -37 mediating IL-6 and IFN-gamma responsiveness and containing a palindromic IL-6/IFN-gamma response element (pIRE). Site-directed mutagenesis of key nucleotides in the ICAM-1 pIRE abolished the effect of both IL-6 and IFN-gamma stimulation, while this pIRE element was sufficient to confer IL-6 and IFN-gamma responsiveness to a heterologous promoter. We further show by gel retardation analysis that distinct nuclear factors induced by both IL-6 or IFN-gamma specifically bind to this pIRE. Furthermore, treatment with IL-6 results in the formation of multiple complexes while IFN-gamma induces a single binding complex, both in HepG2 and monocytic U937 cells. Differentiation of U937 cells by exposure to 12-O-tetradecanoyl phorbol-13-acetate abolishes response to IL-6 but not IFN-gamma. Supershift data utilizing the ICAM-1 pIRE revealed that IFN-gamma and IL-6 both induce a factor antigenically related to IFN-gamma activation factor. We further provide data suggesting that IL-6 additionally activates an ICAM-1 pIRE binding factor related to the previously described acute-phase response factor in disparate cell types. We therefore conclude that the activation of these related nuclear factors by IL-6 and IFN-gamma is important in the regulation of ICAM-1 gene expression.
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PMID:Stimulation of the human intercellular adhesion molecule-1 promoter by interleukin-6 and interferon-gamma involves binding of distinct factors to a palindromic response element. 791 91

Endothelin (ET) produced by endothelial cells has recently been found to be a potent vasoconstricting hormone. In this report, ET is shown to be a potent stimulator of interleukin-6 (IL-6) production by rat bone marrow (BM)-derived stromal cells. It was also shown that ET increased the level of mRNA for IL-6 in these cells. The two types of ET receptor (R), ETAR and ETBR, were shown to be expressed on both BM-derived stromal cells in culture and ex vivo in BM tissue, suggesting that ET works as a physiologic stimulator of IL-6 production in the BM. It was shown that ETAR is coupled to phospholipase C activation, leading to the production of inositol 1,4,5-trisphosphate (IP3) and 1,2-diacylglycerol (DAG) as second messengers in BM-derived stromal cells. This was corroborated by data showing that IL-6 production in these cells was induced by combined stimulation with ionomycin and phorbol myristate acetate, thereby bypassing the effects of IP3 and DAG, respectively. This is the first report on the hormonal regulation of IL-6 production by BM stromal cells, indicating that hematopoiesis is subject to endocrinologic regulation under physiologic conditions. ET has recently been reported to be produced by macrophages in response to bacterial lipopolysaccharide and human immunodeficiency virus-1 glycoprotein 120. These facts, taken together with our findings, raise the possibility that ET shares the same role of IL-1 as a local cytokine, mediating an intercellular signal between macrophages and BM stromal cells in response to bacterial or viral stimulation.
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PMID:Stimulation of interleukin-6 production by endothelin in rat bone marrow-derived stromal cells. 791 71

Because fibronectin (FN) is known to be present in membranes in proliferative vitreoretinopathy, we sought to identify cytokines that regulate the release of FN by retinal pigment epithelial cells (RPE). Levels of FN in the supernatant of cultured human RPE cells were quantified with an ELISA, after which the cells were stimulated with human recombinant cytokines, interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6), interferon gamma (IFN-gamma), transforming growth factor beta 1 and 2 (TGF-beta), and phorbol myristate acetate (PMA). Protein kinase C (PKC) was blocked by 2 nM calphostin C or 1 mM staurosporine. RPE cells released FN into the supernatant constitutively. TGF-beta 1 and TGF-beta 2 upregulated the FN release in a dose- and time-dependent manner. The other cytokines tested were without effect. In combination, IFN-gamma and IL-1 beta reduced the effect of TGF-beta. PMA, which is a PKC activator, also increased the release of FN in a dose-dependent manner. Blocking of PKC with specific inhibitors abolished the effects of TGF-beta and PMA. The results show that TGF-beta is a potent stimulator of FN release by RPE cells, and exerts its effects via signal transduction involving PKC. Its effect is reduced by IFN-gamma.
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PMID:Cytokine effect on fibronectin release by retinal pigment epithelial cells. 795 9

Cytokine generation by tissue-infiltrating mononuclear cells (TIMC) and by keratinocytes (KC) was investigated in material obtained from the oral mucosal tissues of patients with oral lichen planus (OLP). Peripheral blood mononuclear cells (PBMC) and chronically inflamed and noninflamed gingival KC (CIG-KC, NOR-KC, respectively) were used as the controls. Compared to NOR-KC and CIG-KC, KC from OLP patients (OLP-KC) produced much more interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF). The OLP-KC superiority in the production of these cytokines was more prominent when the KC were cultured in the presence of interleukin-1 beta (IL-1 beta), lipopolysaccharide and phorbol myristate acetate. OLP-KC also produced more monocyte-chemotactic factor(s) which were not inactivated by the antibodies against GM-CSF, macrophage colony-stimulating factor and monocyte chemoattractant protein-1. TIMC in OLP tissues (OLP-TIMC) were superior to PBMC in the generation of IL-6 and GM-CSF. OLP-TIMC were stimulated to produce more TNF-alpha by IL-1 beta, IL-6 and GM-CSF, more IL-6 by IL-1 beta and GM-CSF, and more GM-CSF by IL-1 beta and IL-6 than PBMC. When compared to cytokine generation in TIMC from the chronically inflamed gingivae, more interferon-gamma, IL-6 and TNF-alpha were generated by OLP-TIMC. These results indicate that KC play a critical role in OLP, producing cytokines including monocyte-chemotactic factor(s), and that the cytokines produced by TIMC and OLP-KC through autocrine and paracrine processes enhance the local inflammatory response.
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PMID:Cytokine production by keratinocytes and mononuclear infiltrates in oral lichen planus. 796 86

Zinquin [ethyl (2-methyl-8-p-toluenesulphonamido-6-quinolyloxy)acetate], a new intracellular zinc fluorophore, was used to reveal and to measure Zn in cultured rat hepatocytes before and after metallothionein (MT) induction. Hepatocytes labelled with an intense extranuclear fluorescence. Culture with combinations of Zn, dexamethasone and interleukin-6, increased intracellular MT by 24-fold, Zn 3-fold, and Zinquin fluorescence by approx. 2-fold above control values. Zinquin fluorescence correlated in descending order with the total cellular Zn (r = 0.747), exchangeable Zn (r = 0.735), soluble cytosolic Zn (r = 0.669) and MT (r = 0.666). When Zinquin was incubated with a cytosolic fraction of liver proteins before Sephadex G-75 column chromatography, it fluoresced with free, MT-incorporated and protein-bound Zn. Although only a slight attenuation of fluorescence was seen with high-molecular-mass protein-bound Zn, MT was degraded by 60% in the presence of Zinquin. The undegraded Zn-MT fluoresced at about 20% of the expected intensity. Although Zinquin fluoresces with all cytosolic Zn, caution is required when comparisons are made between samples with different concentrations of MT. This limitation was demonstrated by staining liver slices from adjuvant-treated rats where MT was increased 24-fold, intracellular Zn by 77%, but Zinquin fluorescence by only 19% above controls. Nevertheless, Zinquin should prove to be a useful tool for studying the distribution of Zn in living cells.
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PMID:Measurement of zinc in hepatocytes by using a fluorescent probe, zinquin: relationship to metallothionein and intracellular zinc. 798 Apr 47

Ascites is a readily available source of human macrophages (M phi), which can be used to study M phi functions in vitro. We characterized the mediators of inflammation produced by human peritoneal M phi (hp-M phi) obtained from patients with portal hypertension and ascites. The production of the cytokines interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) was found to be lipopolysaccharide (LPS) concentration dependent (0-10 micrograms/ml) with a maximal production at 10 micrograms/ml and also dependent on the time of exposure to the stimulus (0-36 h). IL-1 beta, IL-6 and TNF-alpha production after LPS administration reached a plateau at 24 h. In vitro stimulation for 24 h with LPS does not influence the eicosanoid production from endogenous arachidonate. 13 min of exposure of the cells to the calcium ionophore A23187 gives a significant increase in eicosanoid production from both exogenous and endogenous arachidonate. The main eicosanoids produced are the 5-lipoxgenase products LTB4 and 5-hydroxyeicosatetraenoic acid (HETE). The increase in production of the other eicosanoids is not significant. The eicosanoid production depends on the stimulus concentration. The optimal A23187 concentration is 1 microM. Oxygen radical production was measured in the M phi by a flowcytometric method. The fluorescence intensity of phorbol 12-myristate 13-acetate stimulated and dihydro-rhodamine 123 loaded hp-M phi increases significantly after 15 min. We conclude that LPS stimulation of hp-M phi from liver disease results in similar production of IL-1 beta, IL-6 and TNF-alpha, but that the profile of the eicosanoid production of these M phi stimulated with LPS and A23187 differs from M phi of other origin and species.
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PMID:Production of inflammatory mediators by human macrophages obtained from ascites. 802 53

Interleukin-6 (IL-6) is a multi-functional cytokine that plays a role in the body's response to injury and infection. IL-6 expression is induced in young human diploid fibroblasts (HDF) in response to a number of agents including fetal bovine serum, 12-O-tetradecanoylphorbol-13-acetate, double-stranded RNA, and forskolin. In contrast, we find that senescent HDF are markedly deficient in their ability to express IL-6 in response to serum, double-stranded RNA, and 12-O-tetradecanoyl-phorbol-13-acetate, whereas forskolin is still an effective inducer for senescent cells. Thus, specific pathways for stimulating IL-6 expression appear to be blocked in senescent HDF. The basal amount of IL-6 mRNA in unstimulated senescent HDF is also much lower than in unstimulated young quiescent HDF. Likewise, the amount of IL-6 protein produced by senescent HDF is decreased at least 10-fold. Both the basal and induced levels of IL-6 declined progressively with aging of the HDF in culture, e.g. IL-6 cannot be induced above the young basal level by approximately 65% of life-span completed. If a similar decrease in IL-6 expression takes place in HDF in vivo, it could contribute to the decline in wound healing and the increase in the number and severity of infections experienced by aged individuals.
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PMID:Basal and induced amounts of interleukin-6 mRNA decline progressively with age in human fibroblasts. 803 86

Recombinant growth factors and proinflammatory cytokines were added to primary cultures of human intrahepatic biliary duct epithelia to test for their ability to stimulate DNA synthesis and elicit cytokine production. Interleukin-6 and hepatocyte and epidermal growth factors were found to increase the DNA labeling index of biliary duct epithelium from fourfold to sixfold 24 hr after their addition to primary biliary duct epithelium cultures maintained in serum-free medium. The proliferative responses to all three biliary duct epithelium mitogens peaked within 24 hr, and hepatocyte growth factor was effective over a concentration range of 1.0 to 50 ng/ml, whereas interleukin-6 was effective from 1 to 1,000 U/ml. Insulin-like growth factor, phorbol myristate acetate, interleukin-1 beta and platelet-derived growth factor BB showed mild stimulatory effects, whereas interleukin-4, gamma-interferon, phytohemagglutinin and platelet-derived growth factors AA and AB did not increase DNA synthesis in biliary duct epithelium. Interleukin-1 beta and phorbol myristate acetate were also shown to induce in a dose-dependent fashion a threefold to fivefold increase of interleukin-6 production as measured by enzyme-linked immunosorbent assay in human primary biliary duct epithelium cultures, when compared with hepatocyte growth factor, epidermal growth factor, insulin-like growth factor, phytohemagglutinin, tumor necrosis factor-alpha or platelet-derived growth factor. These results show that interleukin-6 participates in growth regulation of human biliary duct epithelium. This could be exerted in a paracrine or autocrine manner.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Human biliary epithelial cells secrete and respond to cytokines and hepatocyte growth factors in vitro: interleukin-6, hepatocyte growth factor and epidermal growth factor promote DNA synthesis in vitro. 804 98


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