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

The mitogen-activated protein kinase (MAPK) pathway is believed to function as an important mediator of inducible nitric oxide synthase (iNOS) expression. In the present study, we investigated the role of the p38 MAPK signaling pathway in advanced glycosylation end products (AGEs)-induced iNOS expression in C6 glioma cells. AGEs caused a dose-dependent increase of nitrite accumulation in C6 glioma cells. The AGEs-stimulated nitrite production from C6 glioma cells was inhibited by actinomycin D, cyclohexamide, and the NO synthase inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME), suggesting that the increase of AGEs-induced nitrite release is due to iNOS up-regulation. Consistently, treatment of C6 glioma cells with AGEs induced iNOS protein expression. AGEs-stimulated nitrite production was inhibited by pretreatment of C6 glioma cells with anti-AGEs antibodies (1:100 or 1:50). The tyrosine kinase inhibitor (genistein and tyrphostin), the Ras-farnesyl transferase inhibitor (FPT inhibitor-II), or the p38 MAPK inhibitor (SB203580) suppressed AGEs-induced iNOS expression and nitrite release from C6 glioma cells. AGEs activated p38 MAPK in C6 glioma cells, and this effect was blocked by genistein (20 microM), tyrphostin (30 microM), FPT inhibitor-II (20 microM), and SB203580 (10 microM). Taken together, our data suggest that AGEs may activate the pathways of tyrosine kinase and Ras to induce p38 MAPK activation, which in turn induces iNOS expression and NO production in C6 glioma cells.
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PMID:Advanced glycosylation end products induce nitric oxide synthase expression in C6 glioma cells: involvement of a p38 MAP kinase-dependent mechanism. 1169 58

Some biochemical events following the binding of prolactin (PRL) to its receptor in normal human leukocytes were investigated. PRL enhanced JAK2 phosphorylation in peripheral blood mononuclear cells (PBMC) but not in granulocytes. PRL also induced phosphorylation of Stat-5 in PBMC and Stat-1 in granulocytes. Subsequent binding of Stat-5- and of Stat-1-like molecules to a GAS responsive element from the beta-casein promoter was detected by EMSA. p38 MAPK (but not p42/p44 MAPK) was activated by PRL in both leukocyte populations. PRL induced iNOS and CIS mRNA expression in granulocytes. Increased expression of IRF-1 and SOCS-2 was observed in granulocytes and of SOCS-3 and iNOS in PBMC. Similar effects were obtained with ovine and human PRL. Antiserum to PRL reduced iNOS and IRF-1 expression induced by PRL in granulocytes and reduced iNOS expression in PBMC. Also, pretreatment of granulocytes with a p38 MAPK inhibitor (SB 203580) prevented in part PRL-induced iNOS and IRF-1 expression. In PBMC, the p38 inhibitor decreased PRL-induced iNOS gene expression. These results indicate that PRL-induced gene regulation in leukocytes requires the activation of at least two different pathways: the Stat and the MAP kinase pathways. Moreover, although PRL activates Stat in both leukocyte types, signal transduction is different in granulocytes and in PBMC. Most importantly, PRL modulates the expression of genes crucial to leukocyte function. The present findings reinforce the concept that PRL has "cytokine-like" activity in human leukocytes.
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PMID:Cytokine-like effects of prolactin in human mononuclear and polymorphonuclear leukocytes. 1169 20

We investigated the role of stress-activated p38 MAP kinase (p38/SAPK-2) signaling in delayed preconditioning of the heart. Adult male out-bred ICR mice were treated with p38 activator, anisomycin (0.1 mg/kg IP), or vehicle (5% DMSO). Twenty-four hours later, hearts were perfused in Langendorff mode and subjected to 30 minutes of ischemia and 30 minutes of reperfusion. Improvement in postischemic recovery of end-diastolic pressure and reduction in infarct size was observed, which was abolished by SB203580, a specific p38 inhibitor, and pyrrolidinediethyldithiocarbamate (PDTC), the NF-kappaB inhibitor, but not by PD 98059, a specific inhibitor for MEK1 or 2. Transient increase in p38 phosphorylation was observed 15 minutes after anisomycin treatment which subsided by 30 minutes. Electrophoretic mobility shift assay demonstrated rapid activation of NF-kappaB DNA binding with anisomycin, peaking at 30 minutes. Western blot confirmed the accumulation of p50 and p65 in nuclear extracts after anisomycin treatment. Anisomycin-induced NF-kappaB DNA binding activity was inhibited by SB203580 and PDTC. Expression of inducible nitric oxide synthase (iNOS) mRNA, protein, and nitric oxide (NO) synthesis were enhanced in anisomycin-treated mice. SB203580 and PDTC blocked the increased expression of iNOS and increase in synthesis of NO. Selective iNOS inhibitor S-methylisothiourea abolished the protective effect of anisomycin. Furthermore, postischemic cardioprotective effect of anisomycin was absent in mice with targeted ablation of iNOS gene but not in the wild-type B6.129 mice. For the first time, these results suggest that direct pharmacological activation of p38 triggers delayed preconditioning by signaling mechanism involving NF-kappaB activation and synthesis of NO from iNOS.
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PMID:p38 Triggers late preconditioning elicited by anisomycin in heart: involvement of NF-kappaB and iNOS. 1170 19

Bacterial N-formyl peptides such as N-formyl-methionyl-leucyl-phenylalanine (fMLP) are important mediators of monocyte/macrophage recruitment and activation at the sites of inflammation. In the current study, the role of nitric oxide (NO) in the activation of murine peritoneal macrophages to tumoricidal state in response to in vitro fMLP treatment has been investigated. Murine peritoneal macrophages on treatment with fMLP showed a dose- and time-dependent production of NO together with increased tumoricidal activity against P815 mastocytoma cells. L-NMMA, a specific inhibitor of L-arginine pathway, inhibited the fMLP-induced NO secretion and macrophage-mediated tumoricidal activity against P815 cells. These results indicate the L-arginine-dependent production of NO to be one of the effector mechanisms contributing to the tumoricidal activity of fMLP-treated macrophages. The expression of iNOS protein and iNOS mRNA is also observed. The pharmacological inhibitors genistein, wortmannin, H7, PD98059, TPCK, and pertussis toxin (PTX) blocked the fMLP-induced NO production, suggesting the involvement of tyrosine kinases, PI3K, PKC, p42/44 MAPkinase, NF-kappa B, and G-proteins. The expression of phospho-p42/44 MAPK and phospho-I kappa B was also observed. The role of protein phosphatases in the above pathway has been suggested using the specific inhibitors of these phosphatases, i.e., okadaic acid and sodium orthovanadate.
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PMID:fMLP-induced in vitro nitric oxide production and its regulation in murine peritoneal macrophages. 1181 47

In some neurological disorders, excessive nitric oxide (NO, nitrogen monoxide) produced by inducible and/or neuronal nitric oxide synthases (iNOS and nNOS) is able to combine with superoxide (O(minus sign)(2)) to form peroxynitrite (ONOO(minus sign)), which can then induce p53-dependent neural apoptosis. In the present study, experiments using p53 knock-out mice primary neural cells revealed that 3-morpholinosydnonimine hydrochloride (SIN-1), a peroxynitrite donor, triggered apoptosis, while p53-transcriptional activity was effectively suppressed in the absence of p53 molecules. This shows that SIN-1 was able to induce p53-dependent apoptosis in murine primary neural cells. The mechanism responsible for the SIN-1-induced accumulation of p53 molecules was then analyzed. Western blot analysis indicated that p53 accumulation caused by SIN-1 did not require p53 phosphorylation, whereas SIN-1 treatment triggered MAP kinase (MAPK) phosphorylation and pretreatment with the MAP kinase kinase (MEK) inhibitor U0126 inhibited p53 accumulation. Pretreatment of the neural cells with lovastatin, an inhibitor of p21(ras) signaling, greatly inhibited the accumulation of p53 induced by SIN-1. Northern blot and immunofluorescence analyses revealed that primary neural cells treated with SIN-1 had increased levels of p19 alternate reading frame (p19(ARF)) mRNA and protein, which is induced by MAPK and stabilizes the p53 protein. Our findings clearly show that the p21(ras)-MAPK-p19(ARF) pathway has an essential role in p53-dependent apoptosis triggered by peroxynitrite in neural cells.
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PMID:3-Morpholinosydnonimine hydrochloride induces p53-dependent apoptosis in murine primary neural cells: a critical role for p21(ras)-MAPK-p19(ARF) pathway. 1189 Jul 36

The role of p38- and extracellular signal-regulated kinase (ERK) mitogen-activated protein (MAP) kinase pathways in the up-regulation of inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF) production in macrophages stimulated with Streptococcus pneumoniae was examined. Inhibitors of p38 kinases effected significant decreases in the accumulation of iNOS protein in macrophages challenged with pneumococcal cell wall preparations or antibiotic-killed pneumococci, even when added up to 6 h after bacterial challenge. In contrast, ERK pathway inhibitors failed to inhibit pneumococcus-induced iNOS protein accumulation. ERK pathway inhibitors significantly reduced TNF secretion when added at the same time as pneumococcal challenge, and inhibitors of both ERK and p38 pathways reduced TNF secretion when added to the macrophages 1 h before stimulation. These data confirm the importance of the p38 and ERK MAP kinase pathways in macrophage activation by bacterial products but indicate that these 2 kinase pathways regulate different macrophage responses in a temporally distinct manner.
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PMID:Differential effects of p38- and extracellular signal-regulated kinase mitogen-activated protein kinase inhibitors on inducible nitric oxide synthase and tumor necrosis factor production in murine macrophages stimulated with Streptococcus pneumoniae. 1192 Mar 16

The interaction between nitric oxide (NO), progesterone and the MAPkinase signalling pathway involved in decidualization was studied using immunohistochemistry during implantation in the rat. Early pregnant rats were treated with the inhibitor of nitric oxide synthesizing enzyme iNOS, aminoguanidine, either alone or in combination with the low dose antiprogestin, onapristone. The combined treatment was most effective on days 7 and 9 post coitum leading to a complete loss of embryos. The expression pattern of activated MAPkinases, Erk1/2 and iNOS appeared to be associated with the differentiation process of decidualization. A maximum staining of both enzymes was observed on day 9 post coitum in the mesometrial decidua. In addition, Erk1/2 and iNOS were highly coexpressed around the mesometrial sinusoids. Combined treatment with aminoguanidine and onapristone for 3 days led to a transient suppression of Erk1/2 and abolished Cox2 expression. Concomitantly, angiogenesis was reduced and dilated sinusoids were missing in the mesometrial decidua. In conclusion, our study suggests that (i) the member of the mitogen-activated protein kinase (MAPK) family, Erk1/2, is activated during implantation and may play an important role during the decidualization process, and (ii) this enzyme may be regulated by both progesterone and NO.
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PMID:Expression of MAPkinases (Erk1/2) during decidualization in the rat: regulation by progesterone and nitric oxide. 1199 44

Type I collagen comprises the majority of the total body collagens. In particular, bovine type I collagen is utilized for medical purposes and used widely in a variety of cell culture models as a fibrous component of extracellular matrix. This study was designed to explore the effects of type I collagen on the expression of inducible nitric oxide synthase (iNOS) in serum-stimulated Raw264.7 cells and to study the molecular mechanistic basis. Bovine, but not rat or murine, type I collagen increased NO production in serum-stimulated cells, which resulted from the induction of iNOS, as monitored by Northern and Western blot analyses. Bovine type I collagen in combination with serum activated JunB and JunB/AP-1 transcription complex, as evidenced by supershift and immunodepletion of the retarded AP-1 band with anti-JunB antibody. AP-1 complex was immunodepleted in part by anti-c-Jun or anti-JunD antibody. Extracellular signal-regulated kinase1/2 (ERK1/2), p38 kinase, and c-Jun N-terminal kinase (JNK) were all activated by bovine type I collagen in serum-stimulated cells. PD98059, but not SB203580 or JNK1(-) transfection, inhibited both ERK1/2 phosphorylation and JunB/AP-1 activation. Either PD98059 or MKK1(-) transfection suppressed the iNOS induction. The induction of iNOS accompanied activation of NF-kappa B with degradation of I-kappa B alpha. AP-1 and/or NF-kappa B decoy oligonucleotides and pyrrolidine dithiocarbamate suppressed the iNOS induction, which confirmed involvement of AP-1 and NF-kappa B as transcription factors. These results demonstrated that bovine type I collagen induces iNOS in serum-stimulated murine macrophages through JunB/AP-1 and NF-kappa B activation and that activation of ERK1/2 plays an essential role in JunB/AP-1 activation.
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PMID:JunB/AP-1 and NF-kappa B-mediated induction of nitric oxide synthase by bovine type I collagen in serum-stimulated murine macrophages. 1200 50

Mycobacteria are the etiologic agents of numerous diseases which account for significant morbidity and mortality in humans and other animal species. Many mycobacteria are intramacrophage pathogens and therefore the macrophage response to infection, which includes synthesis of cytokines such as tumor necrosis factor alpha (TNF-alpha) and production of nitric oxide, has important consequences for host immunity. However, very little is known about the macrophage cell signaling pathways initiated upon infection or how pathogenic mycobacteria may modulate the macrophage responses. Using primary murine bone marrow macrophages, we established that p38 and extracellular signal-regulated kinases 1 and 2 of the mitogen-activated protein kinase (MAPK) pathways are activated upon infection with different species of mycobacteria. However, we observed decreased MAPK activity over time in macrophages infected with pathogenic Mycobacterium avium strains relative to infections with nonpathogenic mycobacteria. Furthermore, macrophages infected with M. avium produced lower levels of TNF-alpha, interleukin 1beta, and inducible nitric oxide synthase 2 than macrophages infected with nonpathogenic species. Inhibitor studies indicate that the MAPKs are required for the Mycobacterium-mediated induction of these effector proteins. Our data indicate that MAPKs are activated in macrophages upon invasion by mycobacteria and that this activation is diminished in macrophages infected with pathogenic strains of M. avium, resulting in decreased production of important immune effector proteins. The decreased MAPK activation associated with M. avium infections suggests a novel point of immune intervention by this mycobacterial species.
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PMID:Differential regulation of the mitogen-activated protein kinases by pathogenic and nonpathogenic mycobacteria. 1201 Sep 96

Immune stimulants, such as the bacterial endotoxin, lipopolysaccharide (LPS), the human immunodeficiency virus-1 coat protein gp120, or beta-amyloid peptides, lead to glial activation and production of various immune mediators, such as nitric oxide (NO) and proinflammatory cytokines in the brain. These mediators appear to contribute to neuronal cell death in neurodegenerative diseases. However, the signaling pathways, which mediate the neurotoxic effect by the endotoxin, are not understood. The purpose of this study was to determine the role of mitogen-activated protein kinase (MAPK) in LPS-induced neurodegeneration using mesencephalic dopaminergic neuron/glia cultures. We have found that the p38 MAPK is important in LPS-induced death of mesencephalic neurons in rat neuron-glia mixed cultures. Upon treatment with 10 ng/ml LPS, the number of dopaminergic neurons decreased by 80% within 48 h, preceded by a significant production of NO by glia. Neuroprotection by selective inhibition of p38 MAPK activity paralleled a decrease in LPS-induced inducible nitric oxide synthase (iNOS) expression. These events were significantly reduced by the selective p38 MAPK inhibitor, SB202190, but not by the inactive analogue SB202474. Inhibition of iNOS activity and NO production by treatment with GW274150 was also neuroprotective. Although the p38 MAPK inhibitor afforded significant neuroprotection from LPS toxicity in the neuron-glia mixed culture, it failed to protect dopaminergic neurons from 6-hydroxy-dopamine-induced toxicity, which acts directly on dopaminergic neurons by inducing hydroxyl radical formation from the mitochondria. The results suggest that p38 MAPK in glia plays a significant role in the LPS-induced death of mesencephalic neurons through induction of nitric oxide synthase and resulting NO production.
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PMID:p38 MAP kinase is involved in lipopolysaccharide-induced dopaminergic neuronal cell death in rat mesencephalic neuron-glia cultures. 1207 85


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