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)

Primary rat astrocytes express TNF-alpha protein in response to various stimuli including a combined treatment with IFN-gamma and LPS, or IFN-gamma and IL-1 beta. This study was undertaken to further elucidate the mechanisms underlying TNF-alpha gene expression in the astrocyte, and to determine the intracellular signaling pathways involved in IFN-gamma/LPS and/or IFN-gamma/IL-1 beta induction of the TNF-alpha gene. We demonstrate that TNF-alpha mRNA is rapidly induced, and mRNA levels peak after 2 h of stimulation. De novo protein synthesis is not required for TNF-alpha expression because the inclusion of cycloheximide does not prevent expression of the gene and acts to superinduce TNF-alpha mRNA levels. IFN-gamma/LPS induces transcriptional activation of the TNF-alpha gene as assessed by nuclear run-on experiments. Cycloheximide acts to increase both transcription of the TNF-alpha gene and stability of TNF-alpha mRNA thereby resulting in increased TNF-alpha steady state mRNA levels. Two protein kinase C (PKC) inhibitors, H7 and staurosporine, abrogate IFN-gamma/LPS- and IFN-gamma/IL-1 beta-induced TNF-alpha expression in a dose-dependent manner. PKC activity is required for transcription of the TNF-alpha gene, and does not appear to be involved in TNF-alpha mRNA stabilization. Taken together, these data demonstrate that TNF-alpha gene expression in primary rat astrocytes is induced in a PKC-dependent manner.
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PMID:Role of protein kinase C activity in tumor necrosis factor-alpha gene expression. Involvement at the transcriptional level. 146 Feb 80

Interleukin-1 beta (IL-1 beta) induces a dose-dependent increase in the release of corticotropin-releasing factor-41 (CRF) from dispersed rat fetal hypothalamic cells in culture. This release of CRF could be inhibited by the protein kinase C inhibitor H-7, and by the protein kinase A inhibitor IP-20. This suggests that both protein kinase C and protein kinase A-dependent pathways are involved in the response of CRF to IL-1 beta. Dexamethasone also blocked the CRF response to IL-1 beta, indicating that activated glucocorticoid receptors can inhibit the response of CRF to IL-1 beta.
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PMID:Interleukin-1 beta induces corticotropin-releasing factor-41 release from cultured hypothalamic cells through protein kinase C and cAMP-dependent protein kinase pathways. 151 98

The interleukin-1 receptor type I (IL-1RtI) plays an important role in the biological effects of IL-1, but regulation of its surface and gene expression remains unknown. We found that occupancy of 2-15% of the IL-1 surface receptor results in dramatic down-regulation of IL-1RtI both at the mRNA and cell surface level in murine D10S cells, a subline of T-helper type 2 cells. At these low occupancy levels (3 x 10(-12) to 3 x 10(-13) M), the reduction in IL-1RtI surface expression appears at 24 hr and continues to 48 and 72 hr. At the mRNA level, low occupancy of the IL-1R results in decreased IL-1RtI mRNA stability; steady state half-life of the IL-1RtI mRNA is reduced from 6 to 1 hr after exposure to 3 x 10(-12) M IL-1. This down-regulation of IL-1RtI by IL-1 is blocked by cycloheximide, suggesting de novo protein synthesis is necessary for decreased RNA stability. Low concentrations of human IL-1 beta, murine and rabbit IL-1 alpha or beta similarly down-regulated IL-1RtI, whereas low concentrations of human IL-1 alpha failed to reduce the receptor surface expression, despite inducing a full proliferative response. We also observed that the effect of IL-1 on this down-regulation was not through protein kinase C (PKC), since PMA rapidly increased IL-1RtI mRNA levels within 30 min and persisted for 24 hr. IL-2 up-regulated IL-1RtI in D10S cells at both mRNA and protein levels. These results demonstrate that low occupancy of IL-1 receptors induces down-regulation of IL-1RtI surface as well as mRNA expression. The regulation of IL-1RtI gene expression may be one of the mechanisms by which IL-1-mediated events are controlled.
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PMID:Interleukin-1 down-regulates gene and surface expression of interleukin-1 receptor type I by destabilizing its mRNA whereas interleukin-2 increases its expression. 153 88

EL 4-6.1 cells, variants of the murine EL4 thymoma cell line, can be activated by interleukin 1 (IL-1) or phorbol 12-myristate-13-acetate (PMA), or PMA+IL-1 to secrete interleukin 2 (IL-2) and interleukin 4 (IL-4) and to express the IL-2 receptor (IL-2R). To compare the different activation pathways, we examined the effects of staurosporine (STAR) and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), two protein kinase C (PKC) inhibitors, on the induction of interleukin secretion and IL-2R expression in these cells. We report here that nanomolar concentrations of STAR strongly potentiated (20- to 30-fold) the production of IL-2 or IL-4, when EL 4-6.1 cells were induced by IL-1 alpha (or IL-1 beta) alone. By contrast, at identical concentrations, STAR dose-dependently inhibited the production of IL-2 and IL-4 resulting from PMA or PMA+IL-1 cell treatment. STAR also negatively affected the expression of IL-2R, which was dependent on PMA-sensitive PKC with either IL-1, PMA, or PMA+IL-1 stimulation. The changes in interleukin production and IL-2R expression in EL 4-6.1 activated cells were correlated with changes at the mRNA level measured by quantitative polymerase chain reaction (PCR). This finding suggests a pretranslational effect of the drug. At micromolar concentrations, H7 showed the same effects as STAR, but only increased IL-1-triggered interleukin secretions twofold. We observed that the action of PKC inhibitors did not result from modification of IL-1 receptor (IL-1R) expression in EL 4-6.1 cells. Thus, our data show that PKC inhibitors clearly distinguish between IL-1 and PMA stimulatory pathways. In addition, they suggest that the IL-1 stimulatory pathway involves PKC(s) [or other undefined kinase(s)] which regulate this pathway and differ from PKC(s) activated by PMA.
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PMID:Contrasting effects of the protein kinase C inhibitor staurosporine on the interleukin-1 and phorbol ester activation pathways in the EL4-6.1 thymoma cell line. 156 50

The signal transduction pathways by which staphylococcal toxic shock syndrome toxin 1 (TSST-1) induces tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) secretion were examined with various protein kinase inhibitors. TNF-alpha secretion by normal human monocytes and T cells in response to TSST-1 was suppressed by inhibitors of protein kinase C (H7) and tyrosine kinases (genistein). In contrast, the secretion of IL-1 beta was blocked by a cyclic AMP- and cyclic GMP-dependent kinase inhibitor (HA1004) as well as by H7 and genistein. These results suggest that the secretion of TNF-alpha and IL-1 beta may be differentially regulated by TSST-1 and that protein kinases play an important role in mediating cytokine responses to the toxin.
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PMID:Staphylococcal toxic shock syndrome toxin 1-induced tumor necrosis factor alpha and interleukin-1 beta secretion by human peripheral blood monocytes and T lymphocytes is differentially suppressed by protein kinase inhibitors. 163 16

In the human astroglioma cell line CH235-MG, interleukin-1 beta (IL-1 beta) induces transcriptional activation of the tumor necrosis factor-alpha (TNF-alpha) gene, resulting in expression of TNF-alpha mRNA and biologically active TNF-alpha protein. This study was undertaken to elucidate intracellular signaling pathways involved in IL-1 beta induction of the TNF-alpha gene. We demonstrated that the protein kinase C (PKC) activator 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (PMA) in concert with Ca++ ionophore A23187 induced expression of TNF-alpha mRNA and protein, whereas an inactive PMA analogue (alpha PMA) had no effect. Various cyclic nucleotide activators such as 8-Bromo cAMP, cholera toxin, and forskolin had no effect on TNF-alpha production. Two PKC inhibitors, H7 and staurosporine (SS), abrogated IL-1 beta induced TNF-alpha expression in a dose-dependent fashion. Treatment of CH235-MG cells with a high concentration of PMA (1 microM) for an extended period of time (48 h) caused a greater than 90% reduction in total PKC activity. Further strengthening a role for PKC in this cytokine response is the fact that IL-1 beta was no longer able to induce TNF-alpha expression in these PKC depleted cells. Last, IL-1 beta treatment produced an increase of total PKC activity in CH235-MG cells. Taken together, these data demonstrate that IL-1 beta induces TNF-alpha gene expression in CH235-MG cells in a PKC-dependent manner.
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PMID:Interleukin-1 beta induction of TNF-alpha gene expression: involvement of protein kinase C. 163 61

We have examined the role of retinoic acid (RA), the biologically active metabolite of vitamin A, in expression of the IL-1 beta gene in the human myeloid leukemia cell line THP-1 and in human monocytes. Both protein kinase C-activating phorbol esters, e.g., PMA, and LPS induce IL-1 beta expression in these cells. Physiologic RA concentrations alone were not able to induce any IL-1 beta production, but they strongly enhanced the PMA-induced IL-1 beta protein production and mRNA accumulation in both human monocytes and in THP-1 cells. Nuclear run-off analysis revealed that the enhancing effect was at the transcriptional level. RA also slightly potentiated LPS-induced IL-1 beta expression in THP-1 cells but not in human monocytes. These data suggest that RA can be a strong up-regulator of IL-1 production, but its strength varies depending on the nature of the activating signal.
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PMID:Retinoic acid enhances IL-1 beta expression in myeloid leukemia cells and in human monocytes. 164 41

In monocytes, sulfatide, a lipid from Mycobacterium tuberculosis, blocked priming for enhanced release of superoxide (O2-) by the macrophage activating factors lipopolysaccharide, gamma interferon, interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF-alpha), and muramyl dipeptide. Sulfatide, in the presence of lipopolysaccharide, also caused increased secretion of IL-1 beta and TNF-alpha into monocyte culture medium. Sulfatide altered the pattern of phosphorylation of monocyte proteins. Cell lysates prepared from monocytes treated with sulfatide showed decreased activity of protein kinase C, but sulfatide did not directly inhibit protein kinase C activity when added to lysates. A known inhibitor of protein kinase C, staurosporine, also inhibited O2- release and caused increased secretion of IL-1 beta. Thus, sulfatide appeared to indirectly affect protein kinase C, implicating protein kinase C as part of the mechanism of priming. Because sulfatide blocked priming for enhanced release of O2-, which could interfere with monocyte bactericidal activity, while causing enhanced secretion of IL-1 beta and TNF-alpha, which could promote formation of granulomata, sulfatide might be an important factor in the pathogenesis of M. tuberculosis.
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PMID:Monocyte responses to sulfatide from Mycobacterium tuberculosis: inhibition of priming for enhanced release of superoxide, associated with increased secretion of interleukin-1 and tumor necrosis factor alpha, and altered protein phosphorylation. 164 96

It has previously been demonstrated that interleukin-1 (IL-1) is expressed in a variety of fibroblast cell lines. In this study, we investigated the mechanisms involved in the regulation of IL-1 beta production by cultured human dermal fibroblasts. We have shown that IL-1 beta is constitutively expressed as a cell-associated form, with no soluble form detectable in control cell or in stimulated cell supernatants. IL-1 alpha and tumor necrosis factor-alpha (TNF-alpha) exerted a dose-dependent stimulation on the production of the cell-associated IL-1 beta, as estimated using a specific enzyme linked immunosorbent assay (ELISA). As expected, this effect was accompanied by a huge release of prostaglandin E2 (PGE2) and a transient rise in intracellular cyclic AMP. Furthermore, IL-1 beta production was elevated to a lesser extent by the addition of increasing concentrations of the protein kinase C activator phorbol myristate acetate or by low concentration (0.001 microgram/ml) of PGE2. In contrast, higher concentrations (0.1 and 1 micrograms/ml) of PGE2, as well as exogenous dibutyryl-cyclic AMP, were clearly inhibitory. H7, an inhibitor of protein kinases also reduced the stimulatory effect of IL-1 alpha and TNF-alpha. Together with the results obtained with phorbol myristate acetate, these data suggest that protein kinase C may play a role in the upregulation of IL-1 beta expression in normal skin fibroblasts. The addition of indomethacin not only suppressed prostaglandin synthesis, but also dramatically reduced cyclic AMP formation, probably because the PGE2-induced stimulation of adenylate cyclase was abolished. This resulted in a strong potentiation of the stimulatory effect of IL-1 alpha and TNF-alpha, supporting the role of both the cyclooxygenase and adenylate cyclase pathways in the endogenous downregulation of IL-1 beta induction by the two cytokines studied.
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PMID:Induction of interleukin-1 beta production in human dermal fibroblasts by interleukin-1 alpha and tumor necrosis factor-alpha. Involvement of protein kinase-dependent and adenylate cyclase-dependent regulatory pathways. 166 39

Foam cell formation via lipid accumulation through the scavenger receptor in human monocyte/macrophages is believed to be one of the earliest events in atherogenesis. In this study we demonstrate that stimulation of the scavenger receptor activates monocytes to produce interleukin-1 (IL-1). Polyinosinic acid (poly I) and fucoidan, both ligands known to bind to the scavenger receptor, induced IL-1 beta production in human monocytes. Polycytidylic acid, a structurally related compound to poly I, which does not bind to the scavenger receptor, was used as a negative control and had virtually no effect on IL-1 production. THP-1 cells, which normally do not express scavenger receptors, were almost unresponsive to poly I and fucoidan. PMA priming, which has been reported to up-regulate scavenger receptor expression in THP-1 cells, significantly enhanced IL-1 production by fucoidan and poly I. IL-1 produced by scavenger receptor stimulation was shown to be secreted extracellularly, and biologically active. Scavenger receptor-mediated IL-1 production was inhibited by H7, a protein kinase C inhibitor, and enhanced by IBMX, an inhibitor of cyclic AMP degradation, suggesting a synergistic effect of protein kinase C and cyclic AMP-mediated signal transduction pathways in scavenger receptor-mediated IL-1 production. Due to the potentially deleterious effects of IL-1 on the vessel wall, IL-1 produced by ligand binding to the scavenger receptor in human monocytes may play a role in the pathogenesis of atherosclerosis.
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PMID:Induction of interleukin-1 production by ligands binding to the scavenger receptor in human monocytes and the THP-1 cell line. 166 75


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