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)

This present study examines Il-4 regulation of perforin gene expression and cytolytic granule production in alpha CD3-induced activated killer cells CD3-AK. After stimulation of resting T cells with alpha CD3, proliferative response could be detected at 1 day after activation. The expression of perforin mRNA and production of cytolytic granules (using BLT-E as indicator) was detected on days 2-4, and this time course correlated with the generation of lytic CD3-AK cells. These findings indicate that killer cells generation is a late event during the course of alpha CD3 activation. Generation of CD3-AK cells is primarily PKC dependent and is blocked by the depletion or inhibition of PKC by PMA or SSP. These changes are accompanied by the suppression of perforin gene expression (mRNA) and BLT-E production. However, adding IL-4 into the cultures restored the perforin mRNA expression and BLT-E production, and also the cytolytic activity of the CD3-AK cells. Furthermore, for preactivated CD3-AK cells cultured in IL-2, SSP also suppressed the perforin mRNA and BLT-E with the concomitant reduction of cytolytic activity. Similar to the resting T cells, in the SSP-maintained preactivated CD3-AK cells, switching the cytokine from IL-2 to IL-4/IL-2 restored perforin mRNA expression and BLT-E production, with concomitant restoration of the cytolytic activity. In contrast, switching from IL-4/IL-2 gave the opposite effect. These results could be reproduced by using amiloride which also inhibited PKC activity but did not affect the growth of preactivated CD3-AK cells. These findings indicate that IL-4 may play a role in the late stage of alpha CD3 activation to regulate the expression of perforin gene and probably the translation process during the generation of activated killer cells.
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PMID:IL-4 regulation of perforin gene expression and BLT-esterase production in alpha CD3-induced activated killer cells. 860 27

Immune globulin for intravenous use (IVIG) has been used in many inflammatory conditions due to its immunomodulatory potential. The effector mechanisms are incompletely understood. This study dealt with the effects of IVIG on cytokine production in vitro. Cytokine synthesis was identified at the single-cell level using cytokine-specific MAb and indirect immunocytochemical techniques. Peripheral blood mononuclear cells (PBMC) were stimulated for 96 h by immobilized anti-CD3 MAb or by a combination of a protein kinase C activator (PMA) and a calcium ionophore (ionomycin). The addition of IVIG (6 mg/ml) caused a marked inhibition of proliferation and blast transformation despite unaffected cell survival. Anti-CD3-stimulated cultures containing IVIG exhibited a significant inhibition of production of T-cell derived lymphokines IL-2, IL-10, TNF-beta, IFN-gamma and TNF-alpha (made by both monocytes and T cells), while synthesis of the monokine IL-8 was significantly increased. The expression of IL-2 receptors was significantly suppressed. Similar but transient inhibition of most T-cell products (IL-2, IL-3, IL-4, IL-5, IL-10, TNF-beta and GM-CSF) was noted in the PMA/ionomycin-containing cultures. In contrast, no effects were found on IFN-gamma or TNF-alpha production. The superantigen streptococcal pyrogenic exotoxin-A (SPE-A) induced vigorous cell activation and extensive cytokine synthesis. IVIG was added either at the beginning or 24 h after the initiation of cultures in order to elucidate the importance of direct toxin-neutralization. Addition of IVIG from the beginning of cultures induced a strong reduction of blast transformation and an almost complete inhibition of lymphokine production, in particular of IFN-gamma and TNF-beta. Supplementation with IVIG 24 h after initiation of cultures also led to a significant decrease in lymphokine synthesis. Monokine production (IL-1 alpha, IL-1 beta, IL-1ra, IL-6 and IL-8) was either unaffected or even increased. These two facts argue against direct antigen-neutralization as being the only mechanism at work. However, in IVIG-exposed PBMC stimulated with LPS, IL-6 production was significantly reduced. A significant upregulation of IL-1ra was noticed in unstimulated PBMC cultured with IVIG. The results in all the experiments did not indicate a cytotoxic effect by IVIG on cell survival and the production of certain cytokines were unaffected. Instead, the authors believe that the results suggest a previously little examined functional link where the humoral immune response may have direct immunoregulatory effects on the cellular immune system.
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PMID:Intravenous immune globulin affects cytokine production in T lymphocytes and monocytes/macrophages. 862 37

IL-4 and IFN-gamma increase release of secretory component (SC), the polymeric IgA (plgA)-binding segment of the plgA receptor (plgAR), by the human intestinal epithelial cell line HT29. Moreover, these two cytokines synergistically increase plgA binding and cell surface staining for the receptor. To understand better the mechanism by which these cytokines regulate plgAR, we did quantitative immunoblotting using Abs against secretory component. We found that synergy occurs at the level of total cellular plgAR. Additionally, time course studies indicated that maximal receptor levels required >24-h incubation, that reaching maximal levels required at least 18 h of cytokine treatment, and that receptor levels remained elevated as long as cytokines were present. Conversely, if cytokines were removed, then cellular plgAR levels decreased with an approximate t1/2 of 20 h. Finally, synergy required the simultaneous presence of both cytokines throughout the treatment period. Direct measurement of second messengers and inhibitor studies suggest that Ca2+, cAMP, protein kinase A, and protein kinase C do not play major roles in regulating cellular plgAR levels by either cytokine, and do not contribute to the mechanism of synergy. In contrast, protein tyrosine kinase inhibitors potently inhibited all cytokine-dependent increases in total cellular plgAR. These results suggest that IL-4 and IFN-gamma increase cellular plgAR levels in HT29 cells predominantly by activating protein tyrosine kinase-dependent signaling pathways.
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PMID:IL-4 and IFN-gamma synergistically increase total polymeric IgA receptor levels in human intestinal epithelial cells. Role of protein tyrosine kinases. 864 28

To investigate the intracellular pathways leading to ETOH-induced apoptosis, thymocytes and splenic T and B cells were cultured 16 h with or without ETOH and different stimuli, and apoptotic cell death was determined. At concentrations of 0.4%-2% in culture, ETOH induced apoptosis in all three types of cells, but it had a more profound effect on thymocytes and B cells as compared with its effect on T cells. In thymocytes, ETOH-induced apoptosis was abrogated by chelation of extracellular calcium with EGTA, and inhibition of protein synthesis with CHX, or of PKC with H7 but not of PKA with HA 1004. ETOH potentiated the apoptosis of thymocytes induced with the calcium ionophore A23187 and suboptimal doses of PMA, but it had negligible effect on dAMP- and PGE2-induced apoptosis of thymocytes. In contrast to findings in thymocytes, the ETOH-induced apoptosis of T and B cells was almost completely abrogated by PMA, but not by H7 or CHX. In spleen cells, calcium chelation with EGTA triggered apoptosis. ETOH significantly inhibited EGTA-induced apoptosis of B cells but had little effect on EGTA-induced apoptosis of T cells. IL-4 reduced the ETOH-induced apoptosis of B and T cells, but it was not effective in the prevention of apoptosis of thymocytes. Inhibition of the calcium-dependent neutral protease calpain I did not rescue cells from apoptosis. Moreover, treatment with CI-I potentiated ETOH-induced apoptosis in T cells. These results suggest that both thymocytes and splenic T and B cells have relevant apoptotic pathways that can be induced by ETOH, but the mechanisms of ETOH-induced apoptosis differ in these cells.
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PMID:Different pathways of in vitro ethanol-induced apoptosis in thymocytes and splenic T and B lymphocytes. 865 90

The effects of the trichothecene vomitoxin (VT) on the kinetics of cell proliferation and cytokine production were evaluated in murine CD4+ T cells. The CD4+ cultures were stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin to activate protein kinase C and increase cytoplasmic free calcium, respectively, in a range of VT concentrations. Total and viable cell counts at 3, 5, 7, 9, and 11 days revealed delayed or impaired cell proliferation in cultures containing between 50 and 100 ng/ml VT, with complete inhibition being observed at 250 and 500 ng/ml of VT. The VT concentration required to inhibit protein synthesis in a 3-day culture by 50% in this model was 40 ng/ml. When enzyme-linked immunosorbent assay (ELISA) was used to quantitate cytokines, IL-2 levels in control cultures were highest at Day 1 and declined rapidly thereafter, whereas, in VT groups, IL-2 levels were highest at Day 3 and remained elevated up to 11 days. IL-2 levels were elevated by continuous exposure to 100-500 ng/ml of VT with more than 100-fold differences being observed between control and 250 ng/ml VT from Days 5 to 11. When IL-2 levels were expressed on a per viable cell basis, increases were even more marked with as much as 6 log differences being observed between the treatments at 250-500 ng/ml VT and control cultures at Day 7. Supernatant IL-4 and IL-5 levels were also elevated by 100 and 250 ng/ml VT in a dose- and time-dependent fashion compared to control cultures, whereas 500 ng/ml VT was inhibitory. When relative IL mRNA abundance was analyzed during the first 3 days of culture by reverse transcriptase-polymerase chain reaction (RT-PCR) in conjunction with Southern hybridization analysis, IL-2 mRNA levels in Days 1, 2 and 3 in cultures containing 100 and 250 ng/ml VT were greater than corresponding controls. IL-2 mRNA abundance in both control and VT-treated cultures was maximal at Day 1 and decreased rapidly thereafter in controls, whereas much slower rates of IL-2 disappearance were noted in 100 and 250 ng/ml of VT. IL-4 and IL-5 mRNA levels at VT doses of 50 and 100 ng/ml were also elevated compared to controls. Pulsed VT (8 to 48 hr) or cycloheximide (4 to 48 hr) exposure of CD4+ cells enhanced supernatant levels of IL-2 but not IL-4 upon incubation for 24 hr in fresh medium. This effect was not persistent. Taken together, VT enhanced and/or delayed peak IL-2, IL-4, and IL-5 gene expression and secretion in CD4+ T cells stimulated with PMA and ionomycin. Remarkably, cytokine superinduction occurred simultaneously with partial or maximal inhibition of cell proliferation.
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PMID:Vomitoxin-mediated IL-2, IL-4, and IL-5 superinduction in murine CD4+ T cells stimulated with phorbol ester calcium ionophore: relation to kinetics of proliferation. 865 34

Association of interleukin-4 receptor (IL-4R) with phosphatidylinositol 3-kinase (PI3-kinase) has been demonstrated as the proximal event of IL-4 signaling. We investigated the role of this enzyme in the IL-4 signaling pathway in a human Burkitt lymphoma B cell line, DND39, that expresses germline C epsilon transcripts in response to IL-4. Stimulation of DND39 cells with IL-4 resulted in an accumulation of PI-3-monophosphate as well as a decrease of PI-4,5-bisphosphate, which were abrogated by wortmannin, a potent inhibitor of PI3-kinase. Activation of PI3-kinase was further confirmed by the finding that IL-4 caused an increase in PI3-kinase activity coimmunoprecipitated with anti-IL-4R and with anti-JAK3 kinase antibodies. As a possible downstream event of PI3-kinase activation, the translocation of a zeta isoform of protein kinase C (PKC) from the cytosol to the membrane fraction was observed after IL-4 stimulation, and wortmannin also suppressed this translocation. Moreover, IL-4-induced expression of germline C epsilon transcription was inhibited not only by wortmannin, but also by a PKC inhibitor, K252a. These results suggest that the signaling pathway involving PI3-kinase and PKC zeta plays an important role in induction of germline C epsilon transcription in DND39 cells by IL-4.
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PMID:Evidence for a role of phosphatidylinositol 3-kinase in IL-4-induced germline C epsilon transcription. 866 Aug 9

The effects of the trichothecene vomitoxin (VT) on the kinetics of cell proliferation and cytokine production were evaluated in murine CD4(+) T cells. The CD4(+) cultures were stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin to activate protein kinase C and increase cytoplasmic free calcium, respectively, in a range of VT concentrations. Total and viable cell counts at 3, 5, 7, 9, and 11 days revealed delayed or impaired cell proliferation in cultures containing between 50 and 100 ngsolidusml VT, with complete inhibition being observed at 250 and 500 ngsolidusml of VT. The VT concentration required to inhibit protein synthesis in a 3-day culture by 50% in this model was 40 ngsolidusml. When enzyme-linked immunosorbent assay (ELISA) was used to quantitate cytokines, IL-2 levels in control cultures were highest at Day 1 and declined rapidly thereafter, whereas, in VT groups, IL-2 levels were highest at Day 3 and remained elevated up to 11 days. IL-2 levels were elevated by continuous exposure to 100-500 ngsolidusml of VT with more than 100-fold differences being observed between control and 250 ngsolidusml VT from Days 5 to 11. When IL-2 levels were expressed on a per viable cell basis, increases were even more marked with as much as 6 log differences being observed between the treatments at 250-500 ngsolidusml VT and control cultures at Day 7. Supernatant IL-4 and IL-5 levels were also elevated by 100 and 250 ngsolidusml VT in a dose- and time-dependent fashion compared to control cultures, whereas 500 ngsolidusml VT was inhibitory. When relative IL mRNA abundance was analyzed during the first 3 days of culture by reverse transcriptase-polymerase chain reaction (RT-PCR) in conjunction with Southern hybridization analysis, IL-2 mRNA levels in Days 1, 2 and 3 in cultures containing 100 and 250 ngsolidusml VT were greater than corresponding controls. IL-2 mRNA abundance in both control and VT-treated cultures was maximal at Day 1 and decreased rapidly thereafter in controls, whereas much slower rates of IL-2 disappearance were noted in 100 and 250 ngsolidusml of VT. IL-4 and IL-5 mRNA levels at VT doses of 50 and 100 ngsolidusml were also elevated compared to controls. Pulsed VT (8 to 48 hr) or cycloheximide (4 to 48 hr) exposure of CD4(+) cells enhanced supernatant levels of IL-2 but not IL-4 upon incubation for 24 hr in fresh medium. This effect was not persistent. Taken together, VT enhanced andsolidusor delayed peak IL-2, IL-4, and IL-5 gene expression and secretion in CD4(+) T cells stimulated with PMA and ionomycin. Remarkably, cytokine superinduction occurred simultaneously with partial or maximal inhibition of cell proliferation.
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PMID:Vomitoxin-Mediated IL-2, IL-4, and IL-5 Superinduction in Murine CD4+ T Cells Stimulated with Phorbol Ester and Calcium Ionophore: Relation to Kinetics of Proliferation 866 68

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has proliferation- and differentiation-inducing effects on immature myeloid cells in the bone marrow, and it can modulate the function of several types of mature myeloid cells. We have stimulated purified human T cells with immobilized anti-CD3 or mitogenic anti-CD2 (a combination of monoclonal antibodies 9-1 and 9.6) which could induce GM-CSF production. The cytokines interleukin-1 beta (IL-1 beta) and IL-2 strongly enhanced GM-CSF production, while IL-4, IL-6, GM-CSF, interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF) had no effect. Activation of protein kinase C by phorbol myristate acetate or triggering of CD28 on T cells by monoclonal antibody 9.3 provided accessory signals for enhanced GM-CSF production in activated T cells. Most important, the addition of mouse cells transfected with human B7-1 (CD80), a natural ligand for CD28, provided a potent accessory signal for GM-CSF production by activated T cells, which could not be blocked by cyclosporin A. The effect of IL-1 beta was in fact indirect, and resulted from enhanced IL-2 production, while the effect of B7 resulted from both IL-2-dependent and IL-2-independent pathways. We conclude that antigen-presenting cells (APC) can up-regulate GM-CSF production through IL-1 beta and through CD28 triggering by B7 molecules. As GM-CSF itself up-regulates B7 expression and IL-1 beta production by APC, a bidirectional regulatory feedback pathway between APC and T cells seems to modulate GM-CSF production.
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PMID:Production of granulocyte-macrophage colony-stimulating factor by T cells is regulated by B7 and IL-1 beta. 870 49

Lymphokines produced by non-transformed Th clones, Th1 and Th2, were classified into three groups based on their patterns of expression by different stimuli: Group I, GM-CSF and IL-2, characterized by a strict requirement of activation of both the PKC- and calcium-dependent pathways; Group II, IFN-gamma, IL-3, and IL-4, partially induced by calcium ionophore alone; and Group III, IL-5, IL-6, and IL-10, partially induced by either PMA or calcium ionophore alone. Transfection of constitutively active PKC or p21ras replaced the requirement for PMA in expression of these lymphokines, with the exception of GM-CSF. Production of Group II lymphokines was partially induced by constitutively active calcineurin. Production of Group I and II lymphokines was highly sensitive to cyclosporin A, while Group III lymphokines were relatively resistant. Addition of prostaglandin E2 (PGE2) and overexpression of catalytic subunit of protein kinase A inhibited lymphokine production in Th1 cells, but not in Th2 cells, with the exception of GM-CSF. Production of Group III lymphokines induced by PMA alone was upregulated by PGE2, but that of Group II and III lymphokines induced by calcium ionophore alone was not affected. These results suggest that one of the targets of PGE2 is downstream of the PKC-dependent pathway.
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PMID:Signal transduction in Th clones: target of differential modulation by PGE2 may reside downstream of the PKC-dependent pathway. 872 62

Activated B cells express Fas (CD95) and are targets for apoptosis induced by CD4+ Th1 effector cells that kill in a Fas-dependent fashion. We report here that IL-4 reverses the susceptibility to Fas-mediated apoptosis that characterizes CD40-stimulated primary B cells. IL-4-induced Fas resistance is not associated with an alteration in the elevated level of Fas expression produced by CD40 ligand and does not depend on additional receptor-mediated signals. However, IL-4-induced resistance to Th1 cell-mediated cytotoxicity (Th1-CMC) develops more slowly than resistance mediated by surface Ig and is not affected by protein kinase C depletion, unlike anti-Ig-induced Fas resistance. By these two criteria, IL-4-and anti-Ig-induced resistance to Th1-CMC appear to be driven through distinct mechanisms; in keeping with this, suboptimal doses of IL-4 and anti-Ig act in synergy to induce marked protection against Th1-CMC. An important role for IL-4-induced Fas resistance is suggested by the observation that sera from IL-4-overexpressing transgenic mice contain autoreactive Abs.
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PMID:IL-4 induces Fas resistance in B cells. 881 75


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