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)

Progesterone may contribute to the maternal suppression of immunity to the fetus by modulating the Th1/Th2 balance. To clarify whether progesterone directly or indirectly affects T cell differentiation, we used two experimental systems with isolated T cells in vitro. In one system, isolated CD4+CD8+thymocytes differentiated into Th1 and Th2 by two pulse stimulations with defined combinations of ionomycin and PMA followed by the treatment with IL-12, IL-4, and IL-2. In the second system, functional differentiation was induced in purified naive CD4 T cells with cytokines and Abs to CD3 and CD28. In both systems, progesterone added with cytokines suppressed Th1 development at concentrations associated with pregnancy, but enhanced the development of IL-10-producing Th2 cells. Because IL-10 is known to inhibit APC production of IL-12, Th1 development may be also suppressed indirectly by progesterone. However, progesterone failed to enhance IL-10 production in the absence of IL-12. The p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 inhibited Th1 development and enhanced Th2 development, as did progesterone, indicating that p38 MAPK and extracellular signal-regulated kinase pathways are involved in Th1 development. However, the progesterone effects may not be simply due to a modulation of MAPK activities, because the inhibitor did not significantly affect the development of IL-10-producing cells in the presence or absence of progesterone. Glucocorticoids exerted effects similar to those of progesterone on Th1/Th2 development even at lower concentrations. These results suggest that progesterone as well as glucocorticoids directly inhibit Th1 development and enhance Th2 development.
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PMID:Direct and indirect inhibition of Th1 development by progesterone and glucocorticoids. 1180 42

Th cell polarization toward Th1 or Th2 cells is strongly driven by exogenous cytokines, in particular IL-12 or IL-4, if present during activation by Ag-presenting dendritic cells (DC). However, additional Th cell polarizing mechanisms are induced by the ligation of cell surface molecules on DC and naive Th cells. In the present study, the role of LFA-1/ICAM-1 ligation in human Th cell polarization was investigated. Triggering of LFA-1 on anti-CD3/CD28 stimulated naive Th cells with immobilized Fc-ICAM-1, in the absence of DC and exogenous cytokines, induced a marked shift toward Th1 cell development, accompanied by a dose-dependent decrease in GATA-3 expression and a dose-dependent increase in T-bet expression. Th1 polarization by LFA-1 ligation could be demonstrated only under low cytokine conditions, as it was largely overruled by IL-12 or IL-4. This IL-12-independent Th1-driving mechanism appears to be operated by certain subsets of effector DC. Maturation of DC by poly(I:C), a synthetic dsRNA, used as an in vitro model for viral infections, leads to the generation of Th1-driving effector DC (DC1), which express elevated levels of ICAM-1 but produce only low levels of IL-12p70. Blocking the ICAM-1/LFA-1 interaction in cocultures of these DC with naive Th cells attenuated their Th1-driving capacity. The molecular mechanism by which LFA-1 signaling supports Th1 differentiation is blocked by specific inhibitors of extracellular signal-regulated kinase phosphorylation. The present data indicate the existence of an IL-12-independent, extracellular signal-regulated kinase-mediated mechanism, through which high ICAM-1-expressing DC1 can drive Th1 polarization. This mechanism may be operational during viral infections.
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PMID:Intercellular adhesion molecule-1/LFA-1 ligation favors human Th1 development. 1182 1

Tissue inhibitor of metalloproteinase-2 (TIMP-2) is a potent inhibitor of activated matrix metalloproteinases such as gelatinase and collagenase, and thus helps to control extracellular matrix metabolism and deposition by connective tissue cells. We examined the responsiveness of the expression of TIMP-2 to various cytokines in dermal fibroblasts and studied the regulatory and signaling mechanisms of the response. TIMP-2 protein and mRNA expression was induced by IL-4 in a dose- and time-dependent manner, but not by TGF-beta, oncostatin M, or IL-6. IL-4 induction of TIMP-2 expression was dependent upon transcription. The p38 mitogen-activated protein kinase (MAPK) inhibitors SB202190 and SB203580 suppressed IL-4-induced TIMP-2 expression, suggesting the involvement of p38 MAP kinase in the signaling of IL-4 leading to TIMP-2 expression. Immunoblotting analysis using a specific Ab against phosphorylated p38 MAP kinase (Thr(180)/Tyr(182)) showed that IL-4 induced phosphorylation of p38 MAP kinase in human dermal fibroblasts. Furthermore, the p38 MAP kinase assay showed that IL-4 induces p38 MAPK activation in human dermal fibroblasts. The expression of the dominant-negative mutant p38 MAPK represses the IL-4-induced TIMP-2 expression in human dermal fibroblasts. Thus, IL-4 can potentially alter the dermal matrix metabolism by regulating TIMP-2.
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PMID:IL-4 up-regulates the expression of tissue inhibitor of metalloproteinase-2 in dermal fibroblasts via the p38 mitogen-activated protein kinase dependent pathway. 1182 24

Human airway smooth muscle (HASM) cells express interleukin (IL)-13 and IL-4 receptors and respond to these cytokines with signal transducer and activator of transcription-6 and extracellular signal-regulated kinase (ERK) activation. The purpose of this study was to determine whether IL-13 and/or IL-4 influence eotaxin release in HASM cells and whether the ERK mitogen-activated protein (MAP) kinase pathway is involved in these events. Eotaxin release into HASM cell supernatants was assayed by ELISA, and eotaxin mRNA expression was determined by Northern blot analysis. Pretreatment with either IL-13 or IL-4 resulted in a concentration- and time-dependent release of eotaxin, although IL-4 was more effective. Eotaxin release was approximately twice baseline after treatment with 50 ng/ml IL-13 or IL-4 (P < 0.001). IL-13 and IL-4 also acted synergistically with tumor necrosis factor (TNF)-alpha to induce eotaxin release: TNF-alpha alone (10 ng/ml for 24 h) resulted in an approximately fourfold increase in eotaxin release, whereas TNF-alpha in combination with IL-13 or IL-4 resulted in 10- or 20-fold increases (P < 0.05). Similar results were obtained for eotaxin mRNA expression. Pretreatment with either U-0126 (10 microM) or PD-98059 (30 microM), both inhibitors of MAP/ERK kinase, the enzyme upstream of ERK, inhibited IL-13- or IL-4-induced eotaxin release (P < 0.05). U-0126 also inhibited IL-13, and TNF-alpha induced mRNA expression. Our results indicate that IL-13 and IL-4 cause eotaxin release in HASM cells through a mechanism that, in part, involves ERK activation and suggest that the smooth muscle may be an important source of chemokines leading to eosinophil recruitment in asthma.
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PMID:IL-13 and IL-4 cause eotaxin release in human airway smooth muscle cells: a role for ERK. 1188 Mar 12

IL-9 is a Th2 cytokine that exerts pleiotropic activities on T cells, B cells, mast cells, hematopoietic progenitors, and lung epithelial cells, but no effect of this cytokine has been reported so far on mononuclear phagocytes. Human blood monocytes preincubated with IL-9 for 24 h before LPS or PMA stimulation exhibited a decreased oxidative burst, even in the presence of IFN-gamma. The inhibitory effect of IL-9 was specifically abolished by anti-hIL-9R mAb, and the presence of IL-9 receptors was demonstrated on human blood monocytes by FACS. IL-9 also down-regulated TNF-alpha and IL-10 release by LPS-stimulated monocytes. In addition, IL-9 strongly up-regulated the production of TGF-beta1 by LPS-stimulated monocytes. The suppressive effect of IL-9 on the respiratory burst and TNF-alpha production in LPS-stimulated monocytes was significantly inhibited by anti-TGF-beta1, but not by anti-IL-10Rbeta mAb. Furthermore, IL-9 inhibited LPS-induced activation of extracellular signal-regulated kinase 1/2 mitogen-activated protein kinases in monocytes through a TGF-beta-mediated induction of protein phosphatase activity. In contrast, IL-4, which exerts a similar inhibitory effect on the oxidative burst and TNF-alpha release by monocytes, acts primarily through a down-regulation of LPS receptors. Thus, IL-9 deactivates LPS-stimulated blood mononuclear phagocytes, and the mechanism of inhibition involves the potentiation of TGF-beta1 production and extracellular signal-regulated kinase inhibition. These findings highlight a new target cell for IL-9 and may account for the beneficial activity of IL-9 in animal models of exaggerated inflammatory response.
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PMID:IL-9 inhibits oxidative burst and TNF-alpha release in lipopolysaccharide-stimulated human monocytes through TGF-beta. 1193 70

Hepatocyte growth factor (HGF) regulates various physiological and developmental processes in concert with other growth factors, cytokines and hormones. We examined interactions between cell signaling events elicited by HGF and the cytokine interleukin (IL)-4, in the IL-3-dependent murine myeloid cell line 32D transfected with the human HGF receptor, c-Met. HGF was a potent mitogen in these cells, and prevented apoptosis in response to IL-3 withdrawal. IL-4 showed modest anti-apoptotic activity, but no significant mitogenic activity. IL-4 synergistically enhanced HGF-stimulated DNA synthesis, whereas only additive prevention of apoptosis was observed. IL-4 did not enhance HGF-dependent tyrosine phosphorylation of c-Met or Shc. In contrast, HGF-stimulated activation of MAP kinases was enhanced by IL-4, suggesting that the IL-4 and HGF signaling pathways converge upstream of these events. Although phosphatidylinositol 3-kinase (PI3K) inhibitors diminished HGF-induced mitogenesis, anti-apoptosis, and MAP kinase activation, IL-4 enhanced HGF signaling persisted even in the presence of these inhibitors. IL-4 enhancement of HGF signaling was partially blocked in 32D/c-Met cells treated with inhibitors of MEK1 or c-Src kinases, completely blocked by expression of a catalytically inactive mutant of Janus kinase 3 (Jak3), and increased in 32D/c-Met cells overexpressing STAT6. Our results suggest that the IL-4 and HGF pathways converge at multiple levels, and that IL-4-dependent Jak3 and STAT6 activities modulate signaling events independent of PI3K to enhance HGF-dependent mitogenesis in myeloid cells, and possibly other common cellular targets.
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PMID:Mitogenic synergy through multilevel convergence of hepatocyte growth factor and interleukin-4 signaling pathways. 1194 3

The biologic activities of interleukin (IL)-13 and IL-4 often overlap, and evidence supports their importance in atopic disease and airways hyperresponsiveness. Here, their capacity to release eosinophil-activating cytokines was examined in cultured human airway smooth muscle. IL-13 and IL-4 induced selective release of eotaxin with no effect on granulocyte-macrophage colony-stimulating factor, regulated upon activation, normal T-cell expressed and secreted (RANTES), or IL-8. A profound synergistic increase in eotaxin release occurred when IL-13 or IL-4 was combined with IL-1beta that was abrogated by a neutralizing antibody to the IL-4 receptor alpha (IL-4Ralpha)-chain but not to the IL-2 receptor gamma (IL-2Rgamma)-chain. Expression of cell surface IL-4 receptors and IL-4Ralpha in lysates was constitutive and unchanged by treatment with IL-13 or IL-4 alone or in combination with IL-1beta. Activation of IL-4Ralpha by IL-13 or IL-4 induced signal transducer and activation of transcription-6 (STAT6), p42/ p44 ERK, p38, and to a lesser extent, SAPK/JNK mitogen-activated protein kinase phosphorylation. STAT6 and MAP kinase activation by IL-13 or IL-4 was not further potentiated after combined stimulation with IL-1beta. However, eotaxin release induced by IL-13 or IL-4 alone, and in combination with IL-1beta, was prevented by the MEK inhibitor U 0126 and by the p38 inhibitor SB 202190. Collectively, the data suggest that selective eotaxin release induced either by IL-13 and IL-4 or when combined with IL-1beta is mediated by a constitutive cell surface IL-4Ralpha and the activation of multiple intracellular pathways.
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PMID:Selective induction of eotaxin release by interleukin-13 or interleukin-4 in human airway smooth muscle cells is synergistic with interleukin-1beta and is mediated by the interleukin-4 receptor alpha-chain. 1195 62

Interleukin-21 (IL-21) is a recently cloned cytokine with homology to IL-2, IL-4, and IL-15. In this study we examined the effects of IL-21 on human myeloma cells. We found that IL-21 induced proliferation and inhibited apoptosis of the IL-6-dependent human myeloma cell lines ANBL-6, IH-1, and OH-2. The potency of IL-21 was close to that of IL-6 in the OH-2 cell line. Neutralizing antibodies to IL-6 or the IL-6 receptor transducer chain (gp130) did not affect IL-21-induced DNA synthesis, indicating that IL-21-induced proliferation was not mediated through these proteins. Tumor necrosis factor (TNF), another stimulator of myeloma cell growth, up-regulated the expression level of IL-21 receptor (IL-21R), and combinations of TNF and IL-21 gave synergistic effects on myeloma cell proliferation. Furthermore, 4 of 9 purified samples of primary myeloma cells showed a significant increase in DNA synthesis on stimulation of the cells by IL-21. By Western blot analysis, we demonstrated that the intracellular signaling pathways of IL-21 in myeloma cells involved phosphorylation of Jak1, Stat3, and Erk1/2 (p44/42 mitogen-activated protein kinase). IL-21 is a novel growth and survival factor in multiple myeloma and may represent a target for future therapy.
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PMID:Interleukin-21 is a growth and survival factor for human myeloma cells. 1198 33

We examined the co-stimulatory activity of H4/ICOS on murine activated CD4(+) T cells and found that the cross-linking of H4/ICOS enhanced their proliferation, in addition to raising IFN-gamma, IL-4 and IL-10 production to levels comparable to those induced by CD28. However, IL-2 production was only marginally co-stimulated by H4/ICOS. This distinct pattern of lymphokine production appears to be induced by a specific intracellular signaling event. Compared with CD28, H4/ICOS dominantly elicited the Akt pathway via phosphatidylinositol 3-kinase. In addition, mitogen-activated protein kinase family kinases were activated in different ways by CD28 and H4/ICOS. The strong phosphorylation of p46 c-Jun N-terminal kinase was observed upon CD28 co-stimulation, but was less potently induced by H4/ICOS. The strain diversity in the induction of H4/ICOS was recognized. The expression of H4/ICOS on BALB/c activated CD4(+) T cells was >6-fold higher compared with C57BL/6 activated CD4(+) T cells. Furthermore, BALB/c activated CD4(+) T cells exhibited more T(h)2-deviated lymphokine production as compared with C57BL/6 activated CD4(+) T cells and signaling through H4/ICOS during the primary stimulation of naive CD4(+) T cells promoted the generation of T(h)2 cells. Thus, the difference in H4/ICOS expression on activated CD4(+) T cells, which is regulated among the mouse strains, may also regulate the polarization of T(h) cells.
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PMID:A co-stimulatory molecule on activated T cells, H4/ICOS, delivers specific signals in T(h) cells and regulates their responses. 1203 7

Experimental autoimmune encephalomyelitis (EAE) is a CD4(+) T cell-dependent, organ-specific autoimmune model commonly used to investigate mechanisms involved in the activation of autoreactive T(h)1 cells. Mitogen-activated protein kinases such as c-Jun N-terminal kinase (Jnk) 1 and 2 play an important role in the differentiation of naive precursors into T(h)1 or T(h)2 effector cells. To investigate the role of Jnk2 on autoimmunity, Jnk2(-/-) and wild-type mice were immunized with the myelin oligodendrocyte glycoprotein (MOG) 35-55 peptide and the onset of EAE studied. Surprisingly, Jnk2(-/-) mice were as susceptible to EAE as wild-type mice, regardless of whether low or high antigen doses were used to induce disease. In vitro stimulation of lymph node cells from Jnk2(-/-) and wild-type mice resulted in comparable proliferation in response to MOG35-55, Mycobacterium tuberculosis and concanavalin A. MOG35-55-specific T cells lacking Jnk2 showed a T(h)1 cytokine profile with IFN-gamma, but no IL-4 or IL-5 production. No differences in the types of infiltrating cells or myelin destruction in the central nervous system were found between Jnk2(-/-) and wild-type mice, indicating that lack of Jnk2 does not alter the effector phase of EAE. Our results suggest that, despite involvement in T(h)1/T(h)2 differentiation in vitro, Jnk2 is necessary neither for the induction nor effector phase of MOG35-55-induced EAE and nor is it required for antigen-specific IFN-gamma production.
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PMID:Induction of experimental autoimmune encephalomyelitis in the absence of c-Jun N-terminal kinase 2. 1214 21


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