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:2.7.12.2 (MEK)
18,161 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stimulation of rat peritoneal neutrophils with staurosporine (64 nM) induced production of macrophage inflammatory protein-2 (MIP-2) and phosphorylation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase/MAP kinase (ERK/MAPK). The staurosporine-induced MIP-2 production at 4 h was inhibited by the highly specific p38 MAPK inhibitor SB 203580 and the MAPK/ERK kinase (MEK-1) inhibitor PD 98059 in a concentration-dependent manner. By treatment with SB 203580 (1 microM) or PD 98059 (50 microM), the staurosporine-induced increase in the levels of mRNA for MIP-2 was only partially lowered, although the staurosporine-induced MIP-2 production was completely inhibited. Consistent with the inhibition by the protein synthesis inhibitor cycloheximide, SB 203580 and PD 98059 inhibited MIP-2 production at 4 h either when added simultaneously with staurosporine or 2 h after stimulation with staurosporine. In contrast, the DNA-dependent RNA polymerase inhibitor actinomycin D did not inhibit MIP-2 production at 4 h when it was added 2 h after staurosporine stimulation. Dot blot analysis demonstrated that treatment with SB 203580 or PD 98059 down-regulates the stability of MIP-2 mRNA. These results suggested that p38 MAPK and ERK/MAPK pathways are involved in translation of MIP-2 mRNA to protein and stabilization of MIP-2 mRNA.
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PMID:Involvement of p38 MAPK and ERK/MAPK pathways in staurosporine-induced production of macrophage inflammatory protein-2 in rat peritoneal neutrophils. 1035 7

Using rat peritoneal neutrophils, the complete nucleotide sequence of rat macrophage inflammatory protein-2 (MIP-2) mRNA including 5'untranslated region (UTR) and 3'UTR was determined (GenBank Accession number, AB060092). It was found that the MIP-2 mRNA has a 70 bp 5'UTR, a 303 bp coding region and a 728 bp 3'UTR which contains adenylate/uridylate (AU)-rich areas defined as AU-rich elements (AREs). Site-directed mutagenesis studies using the tetracycline-sensitive transactivator protein-expressing rat basophilic leukemia cells (RBL-2H3-TO cells) revealed that MIP-2 mRNA mutants which lack the 3'UTR are more stable than MIP-2-wild-type (wt) mRNA. A MIP-2 mRNA mutant in which some mutations were introduced to the ARE was also stable. The stability of MIP-2 mRNA was low in untreated RBL-2H3-TO cells, but it increased in the antigen-stimulated immunoglobulin E (IgE)-sensitized cells. The antigen-induced MIP-2 mRNA stabilization was counteracted by the highly specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 and the MAPK/ERK kinase (MEK-1) inhibitor PD98059. These findings indicate that ARE is the cis-element which mediates the rapid decay of MIP-2 mRNA, and the antigen stimulation stabilizes MIP-2 mRNA and the p38 MAPK and p44/42 MAPK pathways are involved in the antigen-induced stabilization of MIP-2 mRNA.
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PMID:Analysis of the mechanism regulating the stability of rat macrophage inflammatory protein-2 mRNA in RBL-2H3 cells. 1462 57

Chemokine production has been associated with leukocyte infiltration into the joint during gouty arthritis, and monosodium urate (MSU) crystals, the causative agent of this arthropathy, have been shown to modulate their expression. In the present study, we investigated the transductional mechanisms underlying this cellular regulation in the murine macrophage cell line B10R. We report that MSU crystals rapidly and transiently increase mRNA levels of various chemokines in a concentration-dependent manner. Examination of second messenger activation revealed that macrophage exposure to MSU crystals led to MEK1/2, ERK1/2, and inhibitory protein kappaBalpha phosphorylation as well as to NF-kappaB and AP-1 nuclear translocation. Of interest, specific blockage of the ERK1/2 pathway drastically reduced up-modulation of MSU crystal-mediated chemokine production and activation of nuclear factors. Similarly, selective inhibition of NF-kappaB suppressed NF-kappaB DNA binding activity and the induction of all chemokine transcripts. These findings indicate that ERK1/2-dependent signals seem to be required for AP-1 and NF-kappaB activation and subsequent mRNA expression of the various macrophage chemokines. In addition, transcription and stability assays performed in presence of actinomycin D showed that MSU crystal-mediated MIP-1beta mRNA up-regulation resulted solely from transcriptional control, whereas that of MIP-1alpha, MIP-2, and MCP-1 was due to both gene transcription activation and mRNA posttranscriptional stabilization. Overall, the results of this study help to define the molecular events that govern macrophage chemokine regulation in response to MSU crystals, which is of paramount importance to better understand, and eventually to tame, the inflammatory response during acute gout.
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PMID:Signaling events involved in macrophage chemokine expression in response to monosodium urate crystals. 1547 69

Hepatic ischemia-reperfusion injury is an inevitable consequence during liver surgery. The outcome is particularly poor in cirrhotic livers, which are more prone to hepatic ischemia-reperfusion injury. We aim to study whether FTY720 could attenuate hepatic ischemia-reperfusion injury both in normal and in cirrhotic livers. We applied a 70% liver-ischemia (60 min) model in rats with normal or cirrhotic livers. FTY720 was given 20 min before ischemia and 10 min before reperfusion (1 mg/kg, i.v.). Liver tissues and blood were sampled at 20 min, 60 min, 90 min, 6 h and 24 h after reperfusion for detection of MAPK-Egr-1, Akt pathways and caspase cascade. Hepatic ultrastructure and apoptosis were also compared. FTY720 significantly improved liver function in the rats with normal and cirrhotic livers. Akt pathway was activated at 6 and 24 h after reperfusion. FTY720 significantly down-regulated Egr-1, ET-1, iNOS and MIP-2 accompanied with up-regulation of A20, IL-10, HO-1 and Hsp70. MAPK (Raf-MEK-Erk) pathway was down-regulated. Hepatic ultrastructure was well maintained and fewer apoptotic liver cells were found in the FTY720 groups. In conclusion, FTY720 attenuates ischemia-reperfusion injury in both normal and cirrhotic livers by activation of cell survival Akt signaling and down-regulation of Egr-1 via Raf-MEK-Erk pathway.
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PMID:FTY720 attenuates hepatic ischemia-reperfusion injury in normal and cirrhotic livers. 2824 Aug 25

Dendritic cells (DCs) and chemokines are important in linking innate and adaptive immunity. We previously reported that Fas ligation induced interleukin 1beta (IL-1beta)-dependent maturation and IL-1beta-independent survival of DCs, with extracellular signal-regulated kinase (ERK) and nuclear factor-kappaB (NF-kappaB) signaling pathways involved, respectively. We describe here that Fas ligation induced DCs to rapidly produce both CXC and CC chemokines, including macrophage inflammatory protein 2 (MIP-2), MIP-1alpha, MIP-1beta, monocyte chemoattractant protein 1 (MCP-1), RANTES (regulated on activation normal T cell expressed and secreted), and TARC (thymus and activation-regulated chemokine), resulting in enhanced chemoattraction of neutrophils and T cells by Fas-ligated DCs in vivo or by its supernatant in vitro. These chemokines work synergistically in chemoattraction of neutrophils and T cells with MIP-2 more important for neutrophils, MIP-1alpha and TARC more important for T cells. Moreover, Fas-ligated DCs increased endocytosis by neutrophils and activation and proliferation of antigen-specific naive T cells. Fas ligation-induced DC secretion of chemokines involves Ras/Raf/mitogen-activated protein kinase kinase (MEK)/ERK activation and is ERK, but not NF-kappaB, dependent. Activation of caspases, including caspase 1, but not IL-1 autocrine action, is involved in this process. These data indicate that Fas signaling provides a key link between innate response and adaptive immunity by promoting DC chemokine production.
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PMID:Fas signal links innate and adaptive immunity by promoting dendritic-cell secretion of CC and CXC chemokines. 1594 11

Cot is one of the MAP kinase kinase kinases that regulates the ERK1/ERK2 pathway under physiological conditions. Cot is activated by LPS, by inducing its dissociation from the inactive p105 NFkappaB-Cot complex in macrophages. Here, we show that IL-1 promotes a 10-fold increase in endogenous Cot activity and that Cot is the only MAP kinase kinase kinase that activates ERK1/ERK2 in response to this cytokine. Moreover, in cells where the expression of Cot is blocked, IL-1 fails to induce an increase in IL-8 and MIP-1betamRNA levels. The activation of Cot-MKK1-ERK1/ERK2 signalling pathway by IL-1 is dependent on the activity of the transducer protein TRAF6. Most important, IL-1-induced ERK1/ERK2 activation is inhibited by PP1, a known inhibitor of Src tyrosine kinases, but this tyrosine kinase activity is not required for IL-1 to activate other MAP kinases such as p38 and JNK. This Src kinases inhibitor does not block the dissociation and subsequently degradation of Cot in response to IL-1, indicating that other events besides Cot dissociation are required to activate Cot. All these data highlight the specific requirements for activation of the Cot-MKK1-ERK1/ERK2 pathway and provide evidence that Cot controls the functions of IL-1 that are mediated by ERK1/ERK2.
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PMID:TRAF6 and Src kinase activity regulates Cot activation by IL-1. 1637 Dec 47

We used cytokine protein array to analyze the expression of cytokines from human cord blood-derived mesenchymal stem cells (CB-MSCs). Several cytokines, interleukins (IL), and growth factors, including ENA-78, GM-CSF, GRO, IL-1beta, IL-6, IL-8, MCP-1, OSM, VEGF, FGF-4, FGF-7, FGF-9, GCP-2, IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4, IP-10, LIF, MIF, MIP-3alpha, osteoprotegerin, PARC, PIGF, TGF-beta2, TGF-beta3, TIMP-1, as well as TIMP-2, were secreted by CB-MSCs, while IL-4, IL-5, IL-7, IL-13, TGF-beta1, TNF-alpha, and TNF-beta were not expressed under normal growth conditions. IL-6, IL-8, TIMP-1, and TIMP-2 were the most abundant interleukins expressed by CB-MSCs. A set of growth factors were selected to evaluate their stimulatory effects on the IL6 secretion for CB-MSCs. IL-1beta was the most important factor inducing CB-MSC to secret IL-6. The mechanism by which IL-1beta promoted IL-6 expression in CB-MSCs was studied. By using various inhibitors of signal transduction, we found that activation of p38 mitogen-activated protein kinases (MAPK) and MAPK kinase (MEK) is essential in the IL-1beta stimulated signaling cascade which leads to the increase in IL-6 synthesis. Additionally, continuous supplement of IL-1beta in the CB-MSCs culture will facilitate adipogenic maturation of CB-MSCs as evidenced by the presence of oil drops in the CB-MSCs and secretion of leptin, a molecule marker of adipocytes. These results strongly suggest that cytokine induction and signal transduction are important for the differentiation of CB-MSCs.
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PMID:Cytokine interactions in mesenchymal stem cells from cord blood. 1637 3

Pancreatic and lung inflammation during acute pancreatitis is a poorly understood, but clinically important, phenomenon. The proto-oncogene Tpl2 (tumor progression locus-2) has recently been shown to have important immunomodulatory effects on some inflammatory processes, but its importance to pancreatitis has not been previously examined. Our studies were designed to (a) define the effects of Tpl2 on pancreatic and lung inflammation during pancreatitis and (b) identify mechanisms and cell types responsible for those effects. We examined pancreatitis-associated Tpl2 effects in wild type and Tpl2(-/-) mice subjected to either secretagogue-induced or bile salt-induced pancreatitis. To determine the myeloid or non-myeloid lineage of cells responsible for the Tpl2 effects, we used Tpl2(-/-) chimeric mice generated by lethal irradiation followed by bone marrow transplantation. Mechanisms responsible for the effects of Tpl2 ablation on caerulein-induced proinflammatory events were evaluated under in vivo and in vitro conditions using the techniques of electrophoretic mobility shift assay, immunoblot analysis, and quantitative reverse transcription-PCR. We found that Tpl2 ablation markedly reduced pancreatic and lung inflammation in these two dissimilar models of pancreatitis, but it did not alter pancreatic injury/necrosis in either model. The reduction in caerulein-induced pancreatic inflammation is dependent upon Tpl2 ablation in non-myeloid cells and is associated with both in vivo and in vitro inhibition of MEK, JNK, and AP-1 activation and the expression of MCP-1, MIP-2, and interleukin-6. Non-myeloid cell expression of Tpl2 regulates pancreatic inflammation during pancreatitis by mediating proinflammatory signals and the generation of neutrophil chemoattracting factors.
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PMID:Tumor progression locus-2 is a critical regulator of pancreatic and lung inflammation during acute pancreatitis. 1753 24

Alveolar macrophages, which generate high levels of reactive oxygen species, especially O(2)(*-), are involved in the recruitment of neutrophils to sites of inflammation and injury in the lung, and the generation of chemotactic proteins triggers this cellular recruitment. In this study, we asked whether O(2)(*-) generation in alveolar macrophages had a role in the expression of chemokines. Specifically, we hypothesized that O(2)(*-) generation is necessary for chemokine expression in alveolar macrophages after TNF-alpha stimulation. We found that alveolar macrophages have high constitutive NADPH oxidase activity that was not increased by TNF-alpha, but TNF-alpha increased the activity of the mitochondrial respiratory chain. In addition, the mitochondrial respiratory chain increased O(2)(*-) generation if the NADPH oxidase was inhibited. O(2)(*-) generation was necessary for macrophage inflammatory protein-2 (MIP-2) gene expression, because inhibition of NADPH oxidase or the mitochondrial respiratory chain or overexpression of Cu,Zn-superoxide dismutase significantly inhibited expression of MIP-2. TNF-alpha activated the ERK MAP kinase, and ERK activity was essential for chemokine gene expression. In addition, overexpression of the MEK1-->ERK pathway significantly increased IL-8 expression, and a small interfering RNA to the NADPH oxidase inhibited ERK- and TNF-alpha-induced chemokine expression. Collectively, these results suggest that in alveolar macrophages, O(2)(*-) generation mediates chemokine expression after TNF-alpha stimulation in an ERK-dependent manner.
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PMID:Constitutive NADPH oxidase and increased mitochondrial respiratory chain activity regulate chemokine gene expression. 1770 89

Macrophage inflammatory protein 1 alpha (MIP-1 alpha) is detected at high concentrations in patients with multiple myeloma, and it is thought to play an important role in the etiology of multiple myeloma and osteolysis. Thus, we investigated whether or not YM529/ONO-5920, a new bisphosphonate, inhibited MIP-1 alpha mRNA expression in, and MIP-1 alpha secretion from, mouse myeloma cells. When the cells were stimulated by lipopolysaccharide, increased MIP-1 alpha mRNA expression and MIP-1 alpha secretion were observed. YM529/ONO-5920 inhibited MIP-1 alpha mRNA expression and MIP-1 alpha secretion in a concentration-dependent manner. A transient increase in the phosphorylation of extracellular-regulated kinase 1/2 (ERK1/2) and Akt was observed after lipopolysaccharide stimulation. After YM529/ONO-5920 was given, there was no transient increase in the phosphorylation of ERK1/2 or Akt. These results indicated that YM529/ONO-5920 inhibited the expression and secretion of MIP-1 alpha through blocking the signaling pathway of the Ras/mitogen-activated protein kinase kinase/ERK and Ras/phosphatidylinositol-3 kinase/Akt. Accordingly, YM529/ONO-5920 appears to have promise for use in effective future therapy for osteolysis and myeloma cell growth that depends on MIP-1 alpha.
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PMID:Nitrogen-containing bisphosphonate, YM529/ONO-5920, inhibits macrophage inflammatory protein 1 alpha expression and secretion in mouse myeloma cells. 1797 96


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