Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase whose ligand is collagen. Recently, we have reported the association of DDR1 in the cytokine production of human leukocytes in in vitro and in vivo expression in idiopathic pulmonary fibrosis. However, its role in in vivo inflammation has not been fully elucidated. Small interference RNA (siRNA) can induce specific suppression of in vitro and in vivo gene expression. In this study, using a bleomycin-induced pulmonary fibrosis mouse model, we administered siRNA against DDR1 transnasally and evaluated histological changes, cytokine expression, and signaling molecule activation in the lungs. Histologically, siRNA against DDR1 successfully reduced in vivo DDR1 expression and attenuated bleomycin-induced infiltration of inflammatory cells. Furthermore, it significantly reduced inflammatory cell counts and concentrations of cytokines such as MCP-1, MIP-1alpha, and MIP-2 in bronchoalveolar lavage fluid. Subsequently, bleomycin-induced up-regulation of TGF-beta in bronchoalveolar lavage fluid was significantly inhibited, and collagen deposition in the lungs was reduced. Furthermore, siRNA against DDR1 significantly inhibited bleomycin-induced P38 MAPK activation in the lungs. Considered together, we propose that DDR1 contributes to the development of bleomycin-induced pulmonary inflammation and fibrosis.
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PMID:Suppression of discoidin domain receptor 1 by RNA interference attenuates lung inflammation. 1894 Dec 59

We investigated the effects of simvastatin treatment on the expression of IL-1beta and MCP-1, the activity of NF-kB, and the signaling pathways related to NF-kB activation in a rat model of permanent middle cerebral artery occlusion (pMCAO). IL-1beta and MCP-1 expression, determined using RT-PCR, was enhanced by pMCAO; this effect was inhibited by the administration of simvastatin before ischemia. Pre-treatment with simvastatin abolished the ischemia-induced activation of NF-kB observed in vehicle-treated animals. The evaluation of signal transduction pathways, including extracellular signal-regulated kinase (ERK1/2), SAPK/JNK 46/54 and p38, indicated that only ERK1/2 phosphorylation was enhanced by ischemia, and this activation was prevented by simvastatin. ERK1/2-inhibitor, U0126, reduced brain ischemia but not cytokine induction. These results provide evidence that the HMG-CoA reductase inhibitor induces its effect in the protection of ischemic brain damage with a more complex mechanism which also involve anti-inflammatory properties rather than simple inhibition of ERK1/2 signaling pathway.
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PMID:Activation of NF-kB and ERK1/2 after permanent focal ischemia is abolished by simvastatin treatment. 1648 Aug 88

Triglyceride-rich lipoproteins (TGRLs) are a cardiovascular risk factor and induce endothelial dysfunction. In the present study we investigated the effects of TGRLs from type IV hyperlipidemic and normolipidemic subjects on endothelial activation focusing on the effects on intracellular pathways and gene expression. A total of 54 subjects, 30 hypertriglyceridemic (triglyceride (TG) levels 284+/-101 mg/dl) and 23 normotriglyceridemic (TG levels 109+/-40 mg/dl) were enrolled as lipoprotein donors. TGRLs were isolated from hypertriglyceridemic (H-TGRL) and normotriglyceridemic (N-TGRL) subjects. RNA from human endothelial cells incubated with N-TGRL or H-TGRL was prepared for cDNA microarray analyses. Western blotting was used to study intracellular signaling pathways. Regulated genes were further studied with real-time PCR, immunofluorescence and FACS. Furthermore, a protein/DNA array and chromatin-immunoprecipitation were used to identify transcription factors involved in the observed effects. Both N-TGRL and H-TGRL activated ERK1/2 and p38 MAPK. However, there were differences in the pattern of upregulated target genes between the two types of lipoproteins in HUVECs and/or HAECs: PAI-1, VCAM-1, ELAM-1 and MCP-1 were upregulated by both N-TGRL and H-TGRL, while PECAM-1, IL-6 and ADAMTs1 were selectively upregulated by H-TGRL. Chromatin immunoprecipitation analysis demonstrated the involvement of transcription factors NF-kB and CREB in the activation of these genes. These results support the possible involvement of hypertriglyceridemic TGRLs in endothelial dysfunction via induction of a pro-inflammatory and pro-thrombotic state.
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PMID:Triglyceride-rich lipoproteins from hypertriglyceridemic subjects induce a pro-inflammatory response in the endothelium: Molecular mechanisms and gene expression studies. 1651 17

Evidence from the animal model suggests that proteasome inhibitors may have immunosuppressive properties; however, their effects on the human immune system remain poorly investigated. Here, we show that bortezomib, a proteasome inhibitor with anticancer activity, impairs several immune properties of human monocyte-derived dendritic cells (DCs). Namely, exposure of DCs to bortezomib reduces their phagocytic capacity, as shown by FITC-labeled dextran internalization and mannose-receptor CD206 down-regulation. DCs treated with bortezomib show skewed phenotypic maturation in response to stimuli of bacterial (lipopolysaccharide [LPS]) and endogenous sources (including TNF-alpha and CD40L), as well as reduced cytokine production and immunostimulatory capacity. LPS-induced CCL-2/MCP-1 and CCL5/RANTES secretions by DCs were prevented by DC treatment with bortezomib. Finally, CCR7 up-regulation in DCs exposed to LPS as well as migration toward CCL19/MIP-3beta were strongly impaired. As a suitable mechanism for these effects, bortezomib was found to down-regulate MyD88, an essential adaptor for TLR signaling, and to relieve LPS-induced activation of NF-kappaB, IRF-3, and IRF-8 and of the MAP kinase pathway. In summary, inhibition of DC function may represent a novel mechanism by which proteasome inhibitors exert immunomodulatory effects. These compounds could prove useful for tuning TLR signaling and for the treatment of inflammatory and immune-mediated disorders.
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PMID:Proteasome inhibitor bortezomib modulates TLR4-induced dendritic cell activation. 1653 13

Cytokines, such as IL-1beta and TNF-alpha, contribute to pancreatic beta-cell death in type 1 diabetes mellitus. The transcription factor nuclear factor-kappaB (NF-kappaB) mediates cytokine-induced beta-cell apoptosis. Paradoxically, NF-kappaB has mostly antiapoptotic effects in other cell types. The cellular actions of NF-kappaB depend on the cell type, the nature and duration of the stimulus, the periodicity, and the degree of activity of the particular dimers involved. To clarify the reasons behind the proapoptotic effects of NF-kappaB in pancreatic beta-cells, we compared the pattern of cytokine-induced NF-kappaB activation between rat insulin-producing cells (INS-1E cells) and fibroblasts (208F cells). NF-kappaB activation was induced in INS-1E cells and in 208F cells after exposure to cytokines, but apoptosis was induced only in INS-1E cells, with a more pronounced proapoptotic effect of IL-1beta than of TNF-alpha. NF-kappaB activation in IL-1beta-exposed INS-1E cells was earlier and more marked as compared with TNF-alpha-exposed INS-1E cells or IL-1beta-exposed 208F cells. Both cytokines induced a prolonged (up to 48 h) and stable NF-kappaB activation in INS-1E cells, whereas IL-1beta induced an oscillatory NF-kappaB activation in 208F cells. p65/p65 and p65/p50 were the predominant NF-kappaB dimers in IL-1beta-exposed INS-1E cells and 208F cells, respectively. IL-1beta induced a differential usage of cis-elements in the inducible nitric oxide synthase promoter region in the two cell-lines and an increase in ERK1/2 activity in INS-1E cells but not in 208F cells. Cytokine-induced expression of IkappaB isoforms and other NF-kappaB target genes (Fas, MCP-1, and inducible nitric oxide synthase) was severalfold higher in INS-1E cells than in 208F cells. These results suggest that cytokine-induced NF-kappaB activation in insulin-producing cells is more rapid, marked, and sustained than in fibroblasts, which correlates with a more pronounced activation of downstream genes and a proapoptotic outcome.
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PMID:Cytokine-induced proapoptotic gene expression in insulin-producing cells is related to rapid, sustained, and nonoscillatory nuclear factor-kappaB activation. 1655 31

Mycoplasma can establish latent infections and are associated with arthritis, leukemia, and chronic lung disease. We developed an experimental model in which lung cells are deliberately infected with Mycoplasma fermentans. Human lung fibroblasts (HLF) were exposed to live M. fermentans and immune-modulating cytokine release was assessed with and without known inducers of cytokine production. M. fermentans increased IL-6, IL-8/CXCL8, MCP-1/CCL2, and Gro-alpha/CXCL1 production. M. fermentans interacted with TNF-beta to release more IL-6, CXCL8, and CXCL1 than predicted by the responses to either stimulus alone. The effects of live infection were recapitulated by exposure to M. fermentans-derived macrophage-activating lipopeptide-2 (MALP-2), a Toll-like receptor-2- and receptor-6-specific ligand. The synergistic effect of combined stimuli was more pronounced with prolonged incubations. Preexposure to TNF-beta sensitized the cells to subsequent MALP-2 challenge, but preexposure to MALP-2 did not alter the IL-6 response to TNF-beta. Exposure to M. fermentans or MALP-2 did not enhance nuclear localization, DNA binding, or transcriptional activity of NF-kappaB and did not modulate early NF-kappaB activation in response to TNF-beta. Application of specific inhibitors of various MAPKs suggested that p38 and JNK/stress-activated protein kinase were involved in early IL-6 release after exposure to TNF-beta and M. fermentans, respectively. The combined response to M. fermentans and TNF-beta, however, was uniquely sensitive to delayed application of SP-600125, suggesting that JNK/stress-activated protein kinase contributes to the amplification of IL-6 release. Thus M. fermentans interacts with stimuli such as TNF-beta to amplify lung cell production of immune-modulating cytokines. The mechanisms accounting for this interaction can now be dissected with the use of this in vitro model.
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PMID:Mycoplasma fermentans and TNF-beta interact to amplify immune-modulating cytokines in human lung fibroblasts. 1675 Dec 26

The membrane-anchored form of CX3CL1 has been proposed as a novel adhesion protein for leukocytes. This functional property of CX3CL1 is mediated through CX3CR1, a chemokine receptor expressed predominantly on circulating white blood cells. Thus far, it is still uncertain at what stage of the trafficking process CX3CR1 becomes importantly involved and how the CX3CR1-dependent adhesion of leukocytes is regulated during inflammation. The objective of this study was to examine the functional effects of chemokine stimulation on CX3CR1-mediated adhesion of human monocytes. Consistent with previous reports, our data indicate that the activity of CX3CR1 on resting monocytes is sufficient to mediate cell adhesion to CX3CL1. However, the basal, nonstimulated adhesion activity is low, and we hypothesized that like the integrins, CX3CR1 may require a preceding activation step to trigger firm leukocyte adhesion. Compatible with this hypothesis, stimulation of monocytes with MCP-1 significantly increased their adhesion to immobilized CX3CL1, under both static and physiological flow conditions. The increase of the adhesion activity was mediated through CCR2-dependent signaling and obligatory activation of the p38 MAPK pathway. Stimulation with MCP-1 also induced a rapid increase of CX3CR1 protein on the cell surface. Inhibition of the p38 MAPK pathway prevented this increase of CX3CR1 surface expression and blunted the effect of MCP-1 on cell adhesion, indicating a causal link between receptor surface density and adhesion activity. Together, our data suggest that a chemokine signal is required for firm CX3CR1-dependent adhesion and demonstrate that CCR2 is an important regulator of CX3CL1-dependent leukocyte adhesion.
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PMID:The CC chemokine MCP-1 stimulates surface expression of CX3CR1 and enhances the adhesion of monocytes to fractalkine/CX3CL1 via p38 MAPK. 1675 86

Montelukast and zafirlukast, two cysteinyl leukotriene receptor antagonists (LTRAs), have been shown to have a beneficial effect on the clinical symptoms of asthma. LTRAs can inhibit eosinophil recruitment; however, little is known about their role in monocyte migration. We investigated whether montelukast and zafirlukast could suppress chemokine-induced chemotaxis of monocytes and signaling. Chemotaxis of monocytes from peripheral blood mononuclear cells (PBMCs), cord blood mononuclear cells (CBMCs), and THP-1 cells was evaluated using a 24-well transwell microchamber. [Ca2+]i was measured with the fluorescence calcium indicator fura-2/AM photometry system. p38 MAPK expression was measured by Western blotting. Results showed that montelukast (1-100 microm) and zafirlukast (100 microm) significantly down-regulated monocyte chemoattractant protein-1(MCP-1)-induced chemotaxis of THP-1 cells and human primary monocytes from PBMCs and CBMCs (p<0.05, each comparison). Montelukast also abolished MCP-1-induced [Ca2+]i and pp38 MAPK expression in THP-1 cells in a dose-dependent manner. These data demonstrate that montelukast is effective in down-regulating human monocyte chemotaxis induced by MCP-1. This effect may involve the down-regulation of MCP-1-induced [Ca2+]i and p38 MAPK expression.
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PMID:Effects of leukotriene receptor antagonists on monocyte chemotaxis, p38 and cytoplasmic calcium. 1677 78

Chronic obstructive pulmonary disease [COPD] is characterised by airflow limitation of peripheral airways that is not fully reversible and progressive and is associated with an abnormal inflammatory response of the lungs to noxious particles or gases. There is also intense airway wall remodelling and evidence of systemic inflammation. Increased interleukin [IL]-6, IL-1beta, tumor necrosis factor-alpha [TNF-alpha], GRO-alpha, MCP-1 and IL-8 levels are measured in sputum, with further increases during exacerbations. The bronchiolar epithelium over-expresses MCP-1, MIP-1alpha and IL-8. IL-8 can account for sputum neutrophil chemotactic activity. TNFalpha and IL-1beta stimulate macrophages to produce matrix metalloproteinase-9 [MMP-9], and bronchial epithelial cells to produce extracellular matrix glycoproteins. Increased expression of transforming growth factor-beta [TGFbeta) and epidermal growth factor [EGF] occurs in the epithelium and submucosal cells; gene array studies reveal an excess of TGFbeta1, CTGF and PDGFRA in COPD. TGFbeta and EGF activate proliferation of fibroblasts, while activation of the EGF receptor leads to mucin gene expression. Anti-cytokine therapy could be in the form of soluble receptors or by neutralising antibodies, small compounds blocking cytokine receptors or incomplete and non-activating cytokines, inhibitors of protein activation and inhibitors of signal transduction and transcription such as via inhibition of mitogen-activated protein kinases [MAPK] and of transcription factor, nuclear factor kappaB. Anti-IL-8 therapy has been tried with little effect on COPD, and current trials are on-going with TNF-alpha inhibitors. Other treatments such as phosphodiesterase 4 inhibitors have anti-cytokine effects that may underlie their beneficial effects in COPD.
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PMID:Cytokines as targets in chronic obstructive pulmonary disease. 1678 67

We examined the effects of different bacterial doses of Neisseria gonorrhoeae on the cytokine response of primary human monocytes. The data indicate that a low multiplicity of infection (MOI) challenge (MOI = 0.1) results in substantial production of IL-8 and other chemokines/cytokines, in the absence of significant TNF-alpha production. Positive control challenges (MOI = 10) induced levels of IL-8 that were comparable to the low MOI challenges, but now induced significant levels of TNF-alpha. Induction of IL-8 expression in low MOI challenges was not mediated by an autocrine response as pretreatment of monocytes with neutralizing Abs against TNF-alpha or IL-1beta had no effect on IL-8 expression. IL-8 induction resulting from gonococcal challenge was shown to require NF-kappaB activation, though this activation was limited by the inoculating dose. These data indicate that IL-8 induction results from direct contact between bacteria and monocytes. Analysis of the overall cytokine profile revealed patterns of expression for growth-regulated oncogene, MCP-1, and IL-6 that were similar to IL-8. Analysis of various MAPKs indicated that low MOI challenges were able to efficiently activate both the ERK and p38 pathways, but in contrast to positive control samples, failed to activate the JNK pathway. A lack of phosphorylated JNK leads to decreased production of AP-1 dimers, transcription factors that are critical for efficient transcription of TNF-alpha. Therefore, we propose a mechanism where a low MOI gonococcal challenge results in diminished AP-1 activity and TNF-alpha production while IL-8 levels remain constant.
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PMID:TNF-alpha-independent IL-8 expression: alterations in bacterial challenge dose cause differential human monocytic cytokine response. 1681 92


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