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:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bacterial LPS induce production of cytokines such as IL-1, IL-6, and TNF in mononuclear phagocytes, and this represents a central component in the pathogenesis of septic shock syndrome. However, the mechanisms by which LPS activates these cells to express cytokines are not completely characterized. The present study addressed the role of different protein kinases in the LPS induction of cytokines. It is shown that LPS induced a 12- to 16-fold increase in IL-1 beta, IL-6, and TNF-alpha mRNA levels, and this was completely or more than 80% blocked by the protein tyrosine kinase specific inhibitors herbimycin A and genistein at the concentrations of 1.7 and 37 microM, respectively. Protein kinase C inhibition by staurosporine reduced LPS induction of TNF-alpha, whereas it had no effects on IL-6 and IL-1 beta. Inhibition of protein kinase A by H89 reduced IL-6 mRNA levels but did not detectably change IL-1 beta or TNF-alpha mRNA levels. In contrast, LPS did not increase leukemia inhibitory factor mRNA, which was constitutively expressed and not significantly reduced by these inhibitors. In addition to cytokine mRNA levels, LPS-induced IL-6 protein synthesis and IL-6 bioactivity were also reduced to baseline levels by the PTK inhibitors herbimycin A and genistein. Both PTK inhibitors also reduced the LPS activation of nuclear factor-kappa B (NF-kappa B), which is a transcription factor involved in the expression of cytokine genes such as IL-6 and TNF-alpha. The activation of NF-kappa B was also reduced by H89, whereas staurosporine had no effect on this response. In summary, these findings suggest that protein kinase C and protein kinase A appear to have selective effects in the LPS induction of cytokines, whereas PTK is required for LPS induction of a broad spectrum of cytokines and NF-kappa B activation in monocytes.
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PMID:Protein tyrosine kinase activation is required for lipopolysaccharide induction of cytokines in human blood monocytes. 825 85

Previous studies suggest that heavy chain isotype switch (S) recombination is directed by cytokine-induced transcription of the unrearranged CH gene before recombination. In studies aimed at identifying other signaling pathways that promote switching, we discovered that inhibitors of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) increase LPS-induced switching to IgA in the B cell lymphoma 1.29 mu and to IgG1 in LPS + IL-4-treated splenic B cells. PARP, which binds to and is activated by DNA strand breaks, catalyzes the removal of ADP-ribose from NAD+ and poly(ADP-ribosylation) of chromatin-associated acceptor proteins. This enzyme is believed to function in cellular processes involving DNA strand breaks as well as in modulating chromatin structure. In 1.29 mu cells, PARP inhibitors increase IgA switching by day 2 and cause a fivefold increase in switching on day 3 as assayed by immunofluorescence microscopy. In spleen B cells, the PARP inhibitor nicotinamide increases IgG1 switching by about twofold. Nicotinamide also causes a reduced intensity of hybridization of C mu- and C alpha-specific probes to genomic DNA fragments containing the expressed VDJ-C mu and the unrearranged S alpha-C alpha segments, respectively, in 1.29 mu cells, indicating that PARP inhibition increases rearrangement of these fragments. Induction of switching by PARP inhibitors is not mimicked by treatment with cAMP analogues or reduced by inhibitors of protein kinase A. Induction of switching by PARP inhibitors does not appear to involve increased levels of transcription of the unrearranged C alpha gene.
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PMID:Inhibitors of poly(ADP-ribose) polymerase increase antibody class switching. 825 3

The electrophoretic mobility shift assays (EMSA) with the use of the synthetic HIV-1 NF-kappa B motif as a probe, showed that LPS-treatment of J774 cells (a mouse macrophage cell line) leads to the activation of the fast-moving (denoted as B1) and the slow-moving NF-kappa B (denoted as B2). The binding of both B1 and B2 to the NF-kappa B probe was inhibited specifically by either unlabelled NF-kappa B, or competitor probes, but not by unrelated probes. LPS-induced activation of NF-kappa B was inhibited by a protein kinase A (PKA) inhibitor (H-89), but not by a protein kinase C (PKC) inhibitor (H-7). PMA itself failed to activate NF-kappa B and the depletion of PKC did not prevent LPS-induced activation of NF-kappa B. The pre-treatment of J774 cells with dibutyric cAMP, forskolin, prostaglandin E2 or cholera toxin resulted in NF-kappa B activation. Thus, these data suggested a probable involvement of PKA in LPS-induced NF-kappa B activation in macrophages.
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PMID:Role of protein kinase A in LPS-induced activation of NF-kappa B proteins of a mouse macrophage-like cell line, J774. 839 97

Human monocyte-derived macrophages (M phi) from the majority of normal donors respond to inoculation with Mycobacterium avium, serotype 4, (MAI) by elaboration of the inflammatory monokines TNF-alpha, IL-1 beta, and IL-6, which are of central importance for the protection against bacterial and parasitic infections. Peak TNF-alpha mRNA levels were of brief duration, being maximal at 1.5 h, and were only slightly higher than background levels at 4 h. Increases of IL-1 beta and IL-6 mRNA levels, on the other hand, persisted for 48 to 72 h. In contrast to LPS, MAI induced the production of only small amounts of TNF-alpha protein in the first 12 h and of large amounts of IL-1 beta and IL-6 protein between 3 and 72 h. MAI-induced TNF-alpha transcripts, in contrast to LPS induced TNF-alpha transcripts, were highly unstable. Their accumulation was blocked and their t 1/2 significantly decreased by the protein kinase C inhibitor staurosporine. In contrast, LPS-induced increases of TNF-alpha mRNA levels and MAI-induced increases of IL-1 beta and IL-6 mRNA levels were PKC independent. The cAMP- and cGMP-dependent protein kinase inhibitors, KT5720 and KT5823, respectively, and the tyrosine kinase inhibitors herbimycin and erbstatin had no effect on the MAI-dependent mRNA accumulation of TNF-alpha, IL-1 beta, and IL-6. W7, a calmodulin-dependent protein kinase inhibitor, was inhibitory in all cases. Thus, MAI-induced TNF-alpha mRNA accumulation is of short duration and PKC dependent. MAI-induced TNF-alpha protein production is low, possibly resulting in a mitigated antimicrobial effect.
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PMID:TNF-alpha response of human monocyte-derived macrophages to Mycobacterium avium, serovar 4, is of brief duration and protein kinase C dependent. 845 62

Although the mechanism by which macrophages and other mammalian cells recognize LPS is still only partially understood, there has been considerable recent progress in unraveling the mechanisms by which putative cell surface LPS receptors transmit information of ligand binding to the interior of the cell. In macrophages, LPS induces protein tyrosine phosphorylation of a handful of proteins. We have identified two of the more prominent phosphorylated proteins as p42 and p44 MAP kinases. In addition, we have examined the role of MAP kinases in the macrophage response to LPS by utilizing a regulatable form of Raf-1 to activate MAP kinases independently of LPS. These experiments suggest that MAP kinases participate in LPS signaling, but also demonstrate that activation of MAP kinases cannot account for all of the intracellular events triggered by LPS. Therefore LPS must activate other signaling events that contribute to NF-kappa B activation and TNF-alpha mRNA accumulation and protein secretion.
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PMID:Examination of the role of MAP kinase in the response of macrophages to lipopolysaccharide. 852 48

This study was undertaken to examine the surface expression and regulation of CD14 on human alveolar macrophages (HAM). HAM obtained by bronchoalveolar lavage were cultured with or without LPS and with or without fetal bovine serum (FBS) on plastic or Teflon surfaces. CD14 expression was assessed by immunofluorescence. The roles of protein tyrosine kinase, protein kinase A, and protein kinase C were also evaluated utilizing inhibitors of these enzymes. HAM expressed very low levels of surface CD14 at baseline. CD14 was upregulated on HAM with time in culture in the presence of FBS and/or LPS; adherence did not affect CD14 expression. Inhibitors of protein kinase C and protein tyrosine kinase prevented the upregulation of CD14 by LPS but did not effect the upregulation of CD14 by FBS. These studies show that LPS can upregulate expression of its receptor on HAM and that this effect is accentuated by serum-derived factors.
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PMID:Lipopolysaccharide upregulates surface expression of CD14 on human alveolar macrophages. 857 47

We studied the effects of beta 2-adrenoceptor agonist on IgE production in vitro in human and in vitro and in vivo in mouse. We observed that salbutamol and fenoterol potentiate the IL-4-induced IgE production from peripheral blood mononuclear cells. This effect is associated by an enhanced mRN expression for IgE. Fenoterol also potentiated, but in a lesser extent, the IgE production from purified B lymphocytes stimulated by both IL-4 and CD40, suggesting that the activity of beta 2-adrenoceptor agonist is mediated through T lymphocyte or monocyte modulation. Fenoterol also inhibited the PHA-induced IFN-gamma production by T lymphocytes. Analogues of cAMP or activator of PKA also elicited an increase in IgE production. Moreover, the effect of fenoterol on IgE production was suppressed in the presence of PKA inhibitor. Salbutamol also potentiated the IL-4-induced IgE production from murine splenocytes activated by LPS. Furthermore, mice sensitized to ovalbumin elicited increased IgE responses after daily injection of salbutamol. This was accompanied by an increased in cytokines of Th2 subtypes. Our results showed that beta 2-adrenoceptor agonist, which are currently used in the treatment of asthma, potentiate the IgE production in vitro and in vivo.
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PMID:[Effects of beta-adrenergic compounds on IgE production]. 858 26

Adenosine agonists inhibit TNF-alpha production in macrophage and monocytes, but the mechanism is unknown. Therefore, we studied the human macrophage cell line U937 to determine the adenosine receptor subtypes responsible and the intracellular signaling mechanisms involved. The A1/A3 agonist N6-(4-amino-3-iodobenzyl)adenosine (I-ABA) decreased LPS-stimulated TNF-alpha protein production by 79 +/- 5% (p = 0.003). The mechanism was pretranslational, as adenosine receptor stimulation caused a marked decrease in TNF-alpha mRNA. IL-1 beta, IL-6, and IL-8 mRNA were not changed by adenosine agonists. The rank order of agonists as TNF-alpha inhibitors suggested that the A3 receptor might be involved (N6-(3-iodobenzyl)-9-[5-(methylcarbamoyl)-beta-D-ribofuranosyl] adenosine > 2-chloroadenosine > or = I-ABA > N6 benzyl 5'-N-ethylcarboxamidoadenosine (NECA) > NECA > CGS21680 > N6-cyclohexyladenosine), and this was supported by the fact that a mixed A1/A3 antagonist (xanthine amine congener) reversed the effect, whereas A1-specific (1,3-dipropyl-8-cyclopentylxanthine) and A2-specific (3,7-dimethyl-1-propargylxanthine) antagonists did not. Receptor signaling did not involve cAMP or protein kinase A, nor did it alter the activation and binding characteristics of the transcription factor NF-kappa B. However, the composition of the AP-1 transcription complex was altered by I-ABA. These data suggest that stimulation of the A3 adenosine receptor can alter the cytokine milieu by decreasing TNF-alpha. Adenosine agonists or adenosine regulating agents have potential therapeutic uses in acute and chronic inflammatory diseases.
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PMID:Inhibition of TNF-alpha expression by adenosine: role of A3 adenosine receptors. 861 70

Lipid mediators of inflammation, contribute to airway hyper-reactivity in asthma. Since production of lipid mediators is largely regulated by phospholipase A2 (PLA2), and since PLA2 expression in mesenchymal cells is induced by cytokines and other signals, we examined PLA2 expression by rat tracheobronchial smooth muscle cells (TBSMC). PLA2 expression in TBSMC cultures was markedly increased by tumour-necrosis factor (TNF) alpha (130-fold) and interleukin-1beta (IL-1beta) (7.4-fold). Lipopolysaccharide (LPS;100 ng/ml) resulted in a 51-fold increase in extracellular PLA2 activity. PLA2 expression by LPS-stimulated or cytokine-stimulated cells was downregulated by dexamethasone. Whereas forskolin or dibutyrl cAMP increased PLA2 activity, inhibition of protein kinase A but not tyrosine kinase reduced PLA2 expression. Northern blot analysis showed that TNF alpha and IL-1beta increased both PLA2 and inducible cyclooxygenase (Cox-2) mRNA transcription. Addition of dexamethasone substantially blunted the increase in PLA2 and Cox-2 mRNA. In contrast, the level of Cox-1 mRNA was very low and did not change with the various treatments. Since proinflammatory lipid mediators have been implicated in the pathogenesis of asthma and PLA2 activity regulates generation of these lipid mediators, cytokine-stimulated synthesis and release of PLA2 by airway smooth cells may contribute to the potentiation of airway inflammation in asthma.
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PMID:Secretory non-pancreatic phospholipase A2 and cyclooxygenase-2 expression by tracheobronchial smooth muscle cells. 865 1

Bacterial LPS stimulation of murine macrophages leads to increased tyrosine phosphorylation and activation of the 42- and 44-kDa mitogen-activated protein kinases (MAPK) and the activation of stress-activated protein kinases (SAPK)/c-Jun N-terminal kinase (JNK) and p38, related to the high osmolarity glycerol protein kinase in Saccharomyces cerevisiae (HOG1). LPS caused a rapid increase (10 min) in phosphotransferase activity toward myelin basic protein (MBP), a polypeptide that encompassed the first 169 residues of c-Jun fused to gluthathione S-transferase (GST-c-Jun (1-169)) and 27-kDa heat shock protein (hsp27). MonoQ fractionation of cell extracts resolved phosphotransferase activity peaks toward MBP, GST-c-Jun (1-169), and hsp27, which contained MAPK, SAPK/JNK, and MAPKAPK2, respectively, as indicated by immunoblotting data. In RAW 264.7 macrophages, LPS stimulation of MAPKAPK2, a substrate of p38 HOG1 and MAPK, appeared to occur predominantly via p38 HOG1 and not the MAPK. PMA, which activated the MAPK as potently as LPS, did not strongly activate MAPKAPK2, as assessed by hsp27 phosphorylation. Consistent with p38 HOG1-mediating LPS activation of MAPKAPK2, treatment with LPS, but not PMA, increased the tyrosine phosphorylation of p38 HOG1, a modification known to elevate the enzymatic capacity of this kinase. In LPS-treated cells, the activity of SAPK/JNK was increased 5- to 10-fold, as measured by precipitating SAPK/JNK with Abs or immobilized GST-c-Jun and performing an in vitro kinase assay. In addition, the kinases thought to be upstream of SAPK/JNK, SAPK/ERK kinase 1 (SEK1), and MAPK/ERK kinase kinase 1 (MEKK1), were activated following LPS, but not PMA, exposure (5-fold and 2.5-fold, respectively.
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PMID:Activation of multiple proline-directed kinases by bacterial lipopolysaccharide in murine macrophages. 866 21


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