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)

A member of the IL-1 receptor (IL-1R)-associated kinase (IRAK) family, IRAK4, has been shown to play an essential role in Toll-like receptor (TLR)-mediated signaling. IRAK4 kinase-inactive knockin mice have been shown to be completely resistant to LPS- and CpG-induced shock, due to impaired TLR-mediated induction of pro-inflammatory cytokines and chemokines. A reduction of LPS-, R848- and IL-1-mediated mRNA stability contributes to the reduced cytokine and chemokine production in bone marrow (BM)-derived macrophages from IRAK4 kinase-inactive knockin mice: however, not all of the TLR/IL-1R signaling events are ablated in IRAK4 kinase-inactive knockin mice. A paper in this issue of the European Journal of Immunology shows that, while JNK activation is significantly impaired, NF-kappaB and IRF3 activation are retained in the absence of IRAK4 kinase activity. These residual TLR/IL-1R-induced signaling events allow the production of some cytokines and chemokines (including TNFalpha and CXCL1); at early times after the stimulation and induction of a group of TLR-mediated MyD88/IRAK4-independent genes in IRAK4 kinase-inactive knockin cells. Therefore, pharmacological blocking of IRAK4 kinase activity will retain some levels of host defence, while reducing the levels and duration of inflammatory responses, which should provide beneficial therapies for sepsis and chronic inflammatory diseases.
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PMID:IRAK4 in TLR/IL-1R signaling: possible clinical applications. 1826 2

Plasma membrane cholesterol is critical for neutrophil chemotaxis, although how cholesterol affects chemotactic signaling pathway has not been clearly delineated. Here we demonstrate that cholesterol was absolutely required for polarized redistribution of key chemotactic mediators in human neutrophils in response to all chemoattractants tested (fMet-Leu-Phe, and the chemokines CXCL1, CXCL8 and CXCL12). In particular, PI3K and phosphatidylinositol-3,4,5 triphosphate (PIP(3)) failed to accumulate at the front and phosphatase and tensin homolog (PTEN) at the back of chemoattractant-stimulated neutrophils after cholesterol depletion. Cholesterol depletion did not affect early chemoattractant signaling events such as G-protein activation, intracellular calcium flux or G-protein-independent endocytosis-linked signaling, including the activation of mitogen-activated protein kinase (MAPK), Hck and Fgr transduced by beta-arrestin. During cell polarization, F-actin assemblies redistributed the cholesterol-rich microdomains and cytoskeleton-anchored proteins, including CD16 and CD44 from the leading edge. These data suggest that spatial polarization of chemotactic mediators is orchestrated by protein:protein interactions that organize cholesterol-rich domains of the plasma membrane.
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PMID:Cholesterol is obligatory for polarization and chemotaxis but not for endocytosis and associated signaling from chemoattractant receptors in human neutrophils. 1831 96

Ceramide is recognized as an antiproliferative and proapoptotic sphingolipid metabolite; however, the role of ceramide in inflammation is not well understood. To determine the role of C6-ceramide in regulating inflammatory responses, human corneal epithelial cells were treated with C6-ceramide in 80 nm diameter nanoliposome bilayer formulation (Lip-C6) prior to stimulation with UV-killed Staphylococcus aureus. Lip-C6 (5 muM) inhibited the phosphorylation of proinflammatory and proapoptotic MAP kinases JNK and p38 and production of neutrophil chemotactic cytokines CXCL1, CXCL5, and CXCL8. Lip-C6 also blocked CXC chemokine production by human and murine neutrophils. To determine the effect of Lip-C6 in vivo, a murine model of corneal inflammation was used in which LPS or S. aureus added to the abraded corneal surface induces neutrophil infiltration to the corneal stroma, resulting in increased corneal haze. Mice were treated topically with 2 nMoles (811 ng) Lip-C6 or with control liposomes prior to, or following, LPS or S. aureus stimulation. We found that corneal inflammation was significantly inhibited by Lip-C6 but not control liposomes given prior to, or following, activation by LPS or S. aureus. Furthermore, Lip-C6 did not induce apoptosis of corneal epithelial cells in vitro or in vivo, nor did it inhibit corneal wound healing. Together, these findings demonstrate a novel, anti-inflammatory, nontoxic, therapeutic role for liposomally delivered short-chain ceramide.
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PMID:Inhibition of corneal inflammation by liposomal delivery of short-chain, C-6 ceramide. 1837 42

IL-17A and IL-17F are members of the IL-17 family that play crucial roles in allergic inflammation. Recent studies reported that IL-17A and IL-17F production from a distinct Th lymphocyte subset, Th17, was specifically induced by IL-23, which was produced by dendritic cells and macrophages in response to microbial stimuli. The IL-23-IL-17 axis might therefore provide a link between infections and allergic diseases. In the present study, we investigated the effects of IL-17A, IL-17F, and IL-23, alone or in combination, on cytokine and chemokine release from eosinophils and the underlying intracellular mechanisms. Human eosinophils were found to constitutively express receptors for IL-17A, IL-17F, and IL-23 at the protein level. IL-17A, IL-17F, and IL-23 could induce the release of chemokines GRO-alpha/CXCL1, IL-8/CXCL8, and MIP-1beta/CCL4 from eosinophils, while IL-17F and IL-23 could also increase the production of proinflammatory cytokines IL-1beta and IL-6. Synergistic effects were observed in the combined treatment of IL-17F and IL-23 on the release of proinflammatory cytokines, and the effects were dose-dependently enhanced by IL-23, but not IL-17F. Further investigations showed that IL-17A, IL-17F, and IL-23 differentially activated the ERK, p38 MAPK, and NF-kappaB pathways. Moreover, inhibition of these pathways using selective inhibitors could significantly abolish the chemokine release induced by IL-17A, IL-17F, and IL-23 and the synergistic increases on IL-1beta and IL-6 production mediated by combined treatment of IL-17F and IL-23. Taken together, our findings provide insight for the Th17 lymphocyte-mediated activation of eosinophils via differential intracellular signaling cascades in allergic inflammation.
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PMID:Molecular mechanisms of cytokine and chemokine release from eosinophils activated by IL-17A, IL-17F, and IL-23: implication for Th17 lymphocytes-mediated allergic inflammation. 1839 Jul 47

Chemokines promote vascular inflammation and play a pathogenic role in the development and maintenance of hypertension. In the present study, the expression of the chemokine interleukin-8/CXCL8 (IL-8/CXCL8) was investigated in cultured vascular smooth muscle cells (VSMC) obtained from the thoracic aorta of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). IL-8/CXCL8 expression in thoracic aorta tissue and VSMC in SHR were significantly higher than in WKY. However, the expression of CXCR1 mRNA in VSMC from WKY was higher than that in VSMC from SHR. Angiotensin II (Ang II) induced a higher level of IL-8/CXCL8 mRNA expression in VSMC from SHR than in VSMC from WKY. The time course of Ang II-induced IL-8/CXCL8 expression in VSMC from SHR correlated with those of Ang II-induced CXCL1 and Ang II type 1 (AT1) receptor expression, and the expression of IL-8/CXCL8 by Ang II was inhibited by the AT1 receptor antagonist losartan. The effect of Ang II on IL-8/CXCL8 expression was not dependent on nuclear factor-kappaB (NF-kappaB) activation, but was mediated by an extracellular signal-regulated kinase (ERK) signaling pathway. Although Ang II directly induced IL-8/CXCL8 expression, expression of Ang II-induced IL-8/CXCL8 decreased in VSMC transfected with heme oxygenase-1. These results suggest that IL-8/CXCL8 plays an important role in the pathogenesis of Ang II-induced hypertension and vascular lesions in SHR.
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PMID:Upregulation of interleukin-8/CXCL8 in vascular smooth muscle cells from spontaneously hypertensive rats. 1849 72

Celecoxib is a specific inhibitor of cyclooxygenase 2 (COX2). While it has been used for the treatment of chronic inflammatory conditions, including rheumatoid arthritis, its detailed anti-inflammatory mechanism has not been clarified. Here, we found that Celecoxib potently inhibited TNFalpha-induced transcriptional activity and DNA binding activity of NF-kappaB; however, Celecoxib had no effect on TNFalpha-induced IKK activation and degradation of IkappaBalpha and IkappaBbeta, suggesting that it inhibited NF-kappaB activation via suppressing downstream of IKK activation and IkappaBs degradation. Interestingly, it was also found that Celecoxib abrogated TNFalpha-induced nuclear accumulation of the NF-kappaB p65 subunit. As a result, TNFalpha-induced expression of inflammatory cytokines, CXCL1/KC and CCL2/MCP-1, was clearly inhibited by Celecoxib. On the other hand, Celecoxib had no effect on the TNFalpha-induced nuclear translocation of c-jun and activation of ERK, JNK, p38 and Akt. Taken together, these data indicate that Celecoxib specifically inhibits TNFalpha-induced NF-kappaB activation at the level of its nuclear translocation. This negative regulation of NF-kappaB activation by Celecoxib might be an important mechanism leading to its anti-inflammatory activity.
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PMID:Celecoxib potently inhibits TNFalpha-induced nuclear translocation and activation of NF-kappaB. 1864 47

Allergic diseases such as asthma and allergic dermatitis are associated with the degranulation of mast cells. Chymase, a mast-cell-specific protease, is the major component in mast cell granules that can induce eosinophil infiltration into inflammatory sites. We examined the immunopathological mechanisms for the activation of eosinophils by chymase in allergic inflammation. Cytokines were measured by cytometric bead array Flex Sets multiplex assay using flow cytometry and enzyme-linked immunosorbent assay. Adhesion molecules, migration and intracellular signalling pathways were assessed by flow cytometry, Boyden chamber assay and Western blot, respectively. Chymase suppressed the apoptosis of eosinophils and induce the release of the cytokine interleukin-6 (IL-6) and chemokines CXCL8, CCL2 and CXCL1 by eosinophils dose-dependently. It also up-regulated the surface expression of adhesion molecule CD18 and stimulated the chemokinetic migration of eosinophils. The expressions of adhesion molecules, cytokines and chemokines, and chemokinetic migration were differentially regulated by the activation of extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, Akt, Janus-activated kinase and nuclear factor-kappaB pathways. Chymase therefore plays a pivotal immunological role in the interaction between mast cells and eosinophils in allergic diseases such as allergic dermatitis by inducing adhesion molecule-mediated chemokinetic migration and inflammatory cytokines and chemokines of eosinophils, through multiple intracellular signalling molecules and transcription factor. Our results therefore provide a further biochemical basis for the pathogenesis of allergic inflammation consequent on the interaction between mast cells and eosinophils, and give insight for the development of new therapies.
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PMID:Signalling mechanisms regulating the activation of human eosinophils by mast-cell-derived chymase: implications for mast cell-eosinophil interaction in allergic inflammation. 1877 39

Adequate exercise leads to a vast variety of physiological changes in skeletal muscle as well as other tissues/organs and is also responsible for maintaining healthy muscle displaying enhanced insulin-responsive glucose uptake via GLUT4 translocation. We generated highly developed contractile C(2)C(12) myotubes by manipulating intracellular Ca(2+) transients with electric pulse stimulation (EPS) that is endowed with properties similar to those of in vivo skeletal muscle in terms of 1) excitation-induced contractile activity as a result of de novo sarcomere formation, 2) activation of both the AMP kinase and stress-activated MAP kinase cascades, and 3) improved insulin responsiveness as assessed by GLUT4 recycling. Tbc1d1, a Rab-GAP implicated in exercise-induced GLUT4 translocation in skeletal muscle, also appeared to be phosphorylated on Ser(231) after EPS-induced contraction. In addition, a switch in myosin heavy-chain (MHC) expression from "fast type" to "slow type" was observed in the C(2)C(12) myotubes endowed with EPS-induced repetitive contractility. Taking advantage of these highly developed contractile C(2)C(12) myotubes, we identified myotube-derived factors responsive to EPS-evoked contraction, including the CXC chemokines CXCL1/KC and CXCL5/LIX, as well as IL-6, previously reported to be upregulated in contracting muscles in vivo. Importantly, animal treadmill experiments revealed that exercise significantly increased systemic levels of CXCL1/KC, perhaps derived from contracting muscle. Taken together, these results confirm that we have established a specialized muscle cell culture model allowing contraction-inducible cellular responses to be explored. Utilizing this model, we identified contraction-inducible myokines potentially linked to the metabolic alterations, immune responses, and angiogenesis induced by exercise.
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PMID:Contractile C2C12 myotube model for studying exercise-inducible responses in skeletal muscle. 1878 Jul 77

The IL-23/IL-17 pathway plays an important role in chronic inflammatory diseases, including inflammatory bowel disease. In inflammatory bowel disease, intestinal epithelial cells are an important source of chemokines that recruit inflammatory cells. We examined the effect of IL-17 on chemokine expression of HT-29 colonic epithelial cells. IL-17 strongly repressed TNF-alpha-stimulated expression of CXCL10, CXCL11, and CCL5, but synergized with TNF-alpha for induction of CXCL8, CXCL1, and CCL20 mRNAs. For CXCL10, IL-17 strongly inhibited promoter activity but had no effect on mRNA stability. In contrast, for CXCL8, IL-17 slightly decreased promoter activity but stabilized its normally unstable mRNA, leading to a net increase in steady-state mRNA abundance. IL-17 synergized with TNF-alpha in transactivating the epidermal growth factor receptor (EGFR) and in activating ERK and p38 MAPK. The p38 and ERK pathway inhibitors SB203580 and U0126 reversed the repressive effect of IL-17 on CXCL10 mRNA abundance and promoter activity and also reversed the inductive effect of IL-17 on CXCL8 mRNA, indicating that MAPK signaling mediates both the transcriptional repression of CXCL10 and the stabilization of CXCL8 mRNA by IL-17. The EGFR kinase inhibitor AG1478 partially reversed the effects of IL-17 on CXCL8 and CXCL10 mRNA, demonstrating a role for EGFR in downstream IL-17 signaling. The overall results indicate a positive effect of IL-17 on chemokines that recruit neutrophils (CXCL8 and CXCL1), and Th17 cells (CCL20). In contrast, IL-17 represses expression of CXCL10, CXCL11, and CCR5, three chemokines that selectively recruit Th1 but not other effector T cells.
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PMID:Differential regulation of chemokines by IL-17 in colonic epithelial cells. 1894 Dec 44

p38 mitogen-activated protein kinase (MAPK) signaling is known to be increased in chronic obstructive pulmonary disease (COPD) macrophages. We have studied the effects of the p38 MAPK inhibitor N-cyano-N'-(2-{[8-(2,6-difluorophenyl)-4-(4-fluoro-2-methylphenyl)-7-oxo-7,8-dihydropyrido[2,3-d]-pyrimidin-2-yl]amino}ethyl)guanidine (SB706504) and dexamethasone on COPD macrophage inflammatory gene expression and protein secretion. We also studied the effects of combined SB706504 and dexamethasone treatment. Lipopolysaccharide (LPS)-stimulated monocyte derived macrophages (MDMs) and alveolar macrophages (AMs) were cultured with dexamethasone and/or SB706504. MDMs were used for gene array and protein studies, whereas tumor necrosis factor (TNF) alpha protein production was measured from AMs. SB706504 caused transcriptional inhibition of a range of cytokines and chemokines in COPD MDMs. The use of SB706504 combined with dexamethasone caused greater suppression of gene expression (-8.90) compared with SB706504 alone (-2.04) or dexamethasone (-3.39). Twenty-three genes were insensitive to the effects of both drugs, including interleukin (IL)-1beta, IL-18, and chemokine (CC motif) ligand (CCL) 5. In addition, the chromosome 4 chemokine cluster members, CXCL1, CXCL2, CXCL3, and CXCL8, were all glucocorticoid-resistant. SB706504 significantly inhibited LPS-stimulated TNFalpha production from COPD and smoker AMs, with near-maximal suppression caused by combination treatment with dexamethasone. We conclude that SB706504 targets a subset of inflammatory macrophage genes and when used with dexamethasone causes effective suppression of these genes. SB706504 and dexamethasone had no effect on the transcription of a subset of LPS-regulated genes, including IL-1beta, IL-18, and CCL5, which are all known to be involved in the pathogenesis of COPD.
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PMID:Inhibition of lipopolysaccharide-stimulated chronic obstructive pulmonary disease macrophage inflammatory gene expression by dexamethasone and the p38 mitogen-activated protein kinase inhibitor N-cyano-N'-(2-{[8-(2,6-difluorophenyl)-4-(4-fluoro-2-methylphenyl)-7-oxo-7,8-dihydropyrido[2,3-d] pyrimidin-2-yl]amino}ethyl)guanidine (SB706504). 1900 25


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