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)

The pathogenesis of tuberculosis is complex and its manifestations diverse, reflecting a lifetime of dynamic interactions between mycobacterial virulence factors and the human immune system. The pathogenic mycobacteria have developed strategies to circumvent the major killing mechanisms employed by macrophages and take advantage of the enclosed environment within its host cell to avoid humoral and cell-mediated immune responses. Secretory proteins play a major role in host-pathogen interactions. The eis (Rv2416c) gene has been identified as a secretory protein, and it has been shown that it enhances intracellular survival of Mycobacterium semgmatis in the macrophage cell line. The main aim of this study was to gain insight into the biological role of Eis in the host. Stimulation of T-cells with Eis recombinant protein of Mycobacterium tuberculosis inhibits Con A-mediated T-cell proliferation in vitro. Treatment of T-cells with Eis inhibits ERK1/2, JAK pathway, and subsequent production of tumor necrosis factor-alpha and interleukin-4. On the contrary, there is increased production of interferon-gamma and interleukin-10, which indicates that immunity in response to Eis treatment is skewed away from a protective T(H)1 response and Eis disturbs the cross regulation of T-cells.
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PMID:Eis (enhanced intracellular survival) protein of Mycobacterium tuberculosis disturbs the cross regulation of T-cells. 1744 76

Adiponectin is an adipokine with potent anti-inflammatory properties. However, the mechanisms by which adiponectin suppresses macrophage function are not well understood. Treatment of RAW264.7 macrophages with adiponectin for 18 h decreased lipopolysaccharide (LPS)-stimulated tumor necrosis factor-alpha (TNF-alpha) production. Here we demonstrate that globular adiponectin (gAcrp) initially increased TNF-alpha expression in RAW264.7 macrophages; this TNF-alpha then contributed to increased expression of interleukin-10, which in turn was required for the development of tolerance to subsequent LPS exposure. gAcrp-mediated increases in TNF-alpha mRNA accumulation were associated with increased TNF-alpha promoter activity. gAcrp increased the DNA binding activity of both Egr-1 and NFkappaB; mutation of either the Egr-1 or NFkappaB binding sites in the TNF-alpha promoter decreased gAcrp-stimulated promoter activity. Further, co-transfection with either dominant negative Egr-1 or the IkappaB super-repressor prevented gAcrp-stimulated TNF-alpha promoter activity. gAcrp also increased Egr-1 promoter activity, mRNA accumulation, and DNA binding activity. Inhibition of ERK1/2 with U0126 potently suppressed gAcrp-stimulated Egr-1 promoter activity, as well as TNF-alpha promoter activity. In summary, these data demonstrate that adiponectin initially increases TNF-alpha production by macrophages via ERK1/2-->Egr-1 and NFkappaB-dependent mechanisms; these increases in TNF-alpha in turn lead to increased expression of interleukin-10 and an eventual dampening of LPS-mediated cytokine production in macrophages.
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PMID:Short-term treatment of RAW264.7 macrophages with adiponectin increases tumor necrosis factor-alpha (TNF-alpha) expression via ERK1/2 activation and Egr-1 expression: role of TNF-alpha in adiponectin-stimulated interleukin-10 production. 1753 27

Herpes simplex virus (HSV)-specific T cells are essential for viral clearance. However, T cells do not prevent HSV latent infection or reactivation, suggesting that HSV has the potential to modulate T-cell function. T-cell receptor (TCR) stimulation is a potent and specific means of activating T cells. To investigate how HSV affects T-cell function, we have analyzed how HSV affects TCR-stimulated intracellular signaling and cytokine synthesis in mock-infected and HSV-infected T cells. Mock-infected T cells stimulated through the TCR synthesized a broad range of cytokines that included the proinflammatory cytokines tumor necrosis factor alpha, gamma interferon, and interleukin-2. In contrast, HSV-infected T cells stimulated through the TCR selectively synthesized interleukin-10, a cytokine that suppresses cellular immunity and favors viral replication. To achieve selective interleukin-10 synthesis, HSV differentially affected TCR signaling pathways. HSV inhibited TCR-stimulated formation of the linker for activation of the T-cell signaling complex, and HSV inhibited TCR-stimulated NF-kappaB activation. At the same time, HSV activated the p38 and JNK mitogen-activated protein kinases as well as the downstream transcription factors ATF-2 and c-Jun. HSV did not inhibit TCR-stimulated activation of STAT3, a transcription factor involved in interleukin-10 synthesis. The activation of p38 was required for interleukin-10 synthesis in HSV-infected T cells. The ability of HSV to differentially target intracellular signaling pathways and transform an activating stimulus into an immunosuppressive response represents a novel strategy for pathogen-mediated immune modulation. Selective, TCR-stimulated interleukin-10 synthesis may play an important role in HSV pathogenesis.
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PMID:Herpes simplex virus remodels T-cell receptor signaling, resulting in p38-dependent selective synthesis of interleukin-10. 1780 1

To dissect the molecular basis of the neuroimmune response associated with the genesis of inflammatory (nociceptive) pain, we constructed a herpes simplex virus-based gene transfer vector to express the antiinflammatory cytokine interleukin-10 (IL-10), and used it to examine the effect of IL-10 expression in activated microglial cells in vitro, and in inflammatory pain in vivo. IL-10 reduced the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and decreased the expression of full-length membrane spanning tumor necrosis factor-alpha (mTNFalpha) following lipopolysaccharide stimulation of microglia in vitro. IL-10 also reduced intracellular cleavage of mTNFalpha and release of the soluble cleavage product sTNFalpha. Similar effects on TNFalpha expression were observed when the cells were pretreated with a p38 MAPK inhibitor. In animals, injection of a dilute solution of formalin in the skin resulted in an increase in mTNFalpha in spinal dorsal horn, without detectable sTNFalpha. Local release of IL-10 achieved by gene transfer reduced the number of spontaneous flinches in the early and delayed phases of the formalin test of inflammatory pain. The effect of IL-10 on nocisponsive behavior correlated with a block in phosphorylation of p38 and reduced expression of 26 kDa mTNFalpha in spinal microglia. The results emphasize the key role played by membrane TNFalpha in the spinal neuroimmune response in pain caused by peripheral inflammation.
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PMID:HSV-mediated transfer of interleukin-10 reduces inflammatory pain through modulation of membrane tumor necrosis factor alpha in spinal cord microglia. 1803 11

CC-chemokine ligand 20 (CCL20), a unique chemokine ligand of CC-chemokine receptor 6 (CCR6), play roles in various pathologic conditions. However, the characteristic expression profiles of CCL20 during human tuberculosis (TB) have been largely unknown. The present study analyzed the production and regulatory mechanisms of CCL20 in peripheral blood mononuclear cells (PBMC) and monocyte-derived macrophages (MDM) from active pulmonary TB patients and healthy controls (HC). The 30-kDa antigen (Ag) of Mycobacterium tuberculosis actively induced the production of CCL20 by human PBMC and MDM. A comparative analysis revealed that the expression of CCL20 protein was prominently up-regulated in PBMC, MDM, bronchoalveolar lavage fluids (not in sera) from TB patients compared with the corresponding cells or body fluids from HC. Blockade of either tumour necrosis factor-alpha or interferon-gamma, but not interleukin-10, significantly attenuated the CCL20 production. In addition, recombinant CCL20 induced CCR6 expression by CD45RO+ T lymphocytes in a dose-dependent manner. Furthermore, the expression of CCR6 was significantly increased in CD45RO+ T lymphocytes from TB patients, as compared with those from HC. Pharmacological inhibition studies showed that the 30-kDa Ag-induced CCL20 mRNA expression involves mitogen-activated protein kinases (MAPK; extracellular signal-regulated kinase 1/2 and p38)- and NF-kappaB-dependent signalling. Collectively, the present study demonstrated that TB patients show the up-regulated expression of CCL20, which is modulated by proinflammatory cytokines, and through MAPK/NF-kappaB-mediated transcriptional mechanisms. The findings suggest important implications of potential roles of CCL20-CCR6 in immunopathogenesis of TB.
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PMID:Expression and regulation of the CC-chemokine ligand 20 during human tuberculosis. 1805 67

Adiponectin, an adipokine predominantly secreted from adipose tissue, has potent anti-inflammatory properties. Although the mechanisms for the anti-inflammatory properties of adiponectin are not well understood, recent evidence suggests that increased production of interleukin-10 (IL-10), a potent immunomodulatory cytokine, is involved in the anti-inflammatory actions of adiponectin. Globular adiponectin (gAcrp) increased IL-10 promoter activity and IL-10 mRNA accumulation in RAW 264.7 macrophages. Deletion of the sequences from -416 and -369 in the IL-10 promoter, containing a cyclic AMP-response element (CRE), decreased gAcrp-induced IL-10 promoter activation. Treatment of RAW 264.7 macrophages with gAcrp increased the phosphorylation of cyclic AMP response element binding protein (CREB) at Ser(133), as well as enhanced the DNA binding activity of CREB. Further, overexpression of a dominant negative form of CREB suppressed gAcrp-induced transcriptional activation of IL-10. gAcrp-stimulated CREB phosphorylation was mediated by the activation of both ERK1/2- and cAMP-dependent protein kinase (PKA)-dependent pathways. Inhibition of either ERK1/2 or PKA activity prevented gAcrp-stimulated CREB phosphorylation, as well as gAcrp-stimulated IL-10 promoter activation. Taken together, these data identify gAcrp-stimulated phospho-CREB as a key transcription factor responsible for gAcrp-induced IL-10 promoter activation.
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PMID:Activation of cyclic-AMP response element binding protein contributes to adiponectin-stimulated interleukin-10 expression in RAW 264.7 macrophages. 1826 67

Ceftiofur is a new broad-spectrum, third-generation cephalosporin antibiotic for veterinary use. Immunopharmacological studies can provide new information on the immunomodulatory activities of some drugs, including their effect on cytokine productions. For this reason, we investigated the effect of ceftiofur on cytokine productions in vitro. We found that ceftiofur can downregulate tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6), but did not affect interleukin-10 (IL-10) production. We further investigated signal transduction mechanisms to determine how ceftiofur affects. RAW 264.7 cells were pretreated with 1, 5, or 10 mg/L of ceftiofur 1 h prior to treatment with 1 mg/L of LPS. Thirty minutes later, cells were harvested and mitogen activated protein kinases (MAPKs) activation was measured by Western blot. Alternatively, cells were fixed and nuclear factor-kappaB (NF-kappaB) activation was measured using immunocytochemical analysis. Signal transduction studies showed that ceftiofur significantly inhibited extracellular signal-regulated kinase (ERK), p38, and c-jun NH(2)-terminal kinase (JNK) phosphorylation protein expression. Ceftiofur also inhibited p65-NF-kappaB translocation into the nucleus. Therefore, ceftiofur may inhibit LPS-induced production of inflammatory cytokines by blocking NF-kappaB and MAPKs signaling in RAW264.7 cells.
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PMID:Ceftiofur impairs pro-inflammatory cytokine secretion through the inhibition of the activation of NF-kappaB and MAPK. 1847 28

The double-stranded RNA-activated protein kinase R (PKR) is an important component of antiviral defense. PKR participates in different signaling pathways in response to various stimuli to regulate translation via phosphorylation of the eukaryotic initiation factor 2alpha, and transcription via activating NF-kappaB and IRF-1, to induce pro-inflammatory cytokines. Here we show PKR regulates interleukin-10 induction in response to double-stranded RNA, bacterial lipopolysaccaride, and Sendai virus infection. Using chemical inhibitors, dominant negative constructs, and genetic knockouts, we demonstrate that the PKR-mediated interleukin-10 induction engages JNK and NF-kappaB. Together, our data demonstrate the role of PKR in regulating an anti-inflammatory cytokine. The findings have significance in antiviral as well as broader innate immune responses.
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PMID:Protein kinase R-dependent regulation of interleukin-10 in response to double-stranded RNA. 1862 2

Anti-ribosomal phosphoprotein autoantibodies have been shown to be significantly associated with multiple manifestations of systemic lupus erythematosus (SLE). High levels of interleukin-10 (IL-10) have been demonstrated to contribute to lupus susceptibility and severity. In this study, we investigated the molecular mechanisms of anti-ribosomal phosphoprotein monoclonal antibody (anti-P mAb)-induced autoimmune responses. Anti-P mAb promoted IL-10 overproduction in a dose- and time-dependent manner in both lipopolysaccharide (LPS)-activated RAW 264.7 cells and primary human macrophages. Anti-P mAb enhanced phosphorylation of Akt (PKB; protein kinase B), extracellular signal regulated kinase 1/2 (ERK1/2) and c-Jun NH2-terminal kinase 1/2 (JNK1/2), while phosphorylation of p38 remained unaltered. Furthermore, anti-P mAb decreased glycogen synthase kinase 3 (GSK3) activity and reduced the phosphorylation of I kappaB alpha in LPS-activated macrophages. The Syk, phosphatidylinositol 3-kinase (PI3K), protein kinase C (PKC), JNK and ERK signalling pathways involved in anti-P mAb-triggered IL-10 secretion were also confirmed using various pharmacological inhibitors. In addition, nuclear factor (NF)-kappaB had negative regulatory effects on anti-P mAb-triggered IL-10 secretion. Using reporter plasmids containing the nuclear factor binding sites of NF-kappaB, cAMP-enhanced activation protein 1 (AP-1), serum response element (SRE) or cyclic AMP response element (CRE), treatment of anti-P mAb led to activation of the corresponding factors that bind to the AP-1 site, SRE and CRE in the LPS-activated macrophages. Furthermore, by transfection with reporter plasmids bearing various lengths of the IL-10 promoter, the AP-1 binding site, SRE and CRE were shown to be required for anti-P mAb-induced effects. Collectively, our results provide a molecular model for anti-P mAb-induced IL-10 overproduction in LPS-activated macrophages, which may play a role in the pathogenesis of SLE.
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PMID:Anti-ribosomal phosphoprotein autoantibody triggers interleukin-10 overproduction via phosphatidylinositol 3-kinase-dependent signalling pathways in lipopolysaccharide-activated macrophages. 1877 81

Alveolar macrophages represent critical effector cells of innate immunity to infectious challenge in the lungs and recognize bacterial pathogens through pattern recognition receptors such as Toll-like receptors (TLRs). Phosphatidylinositol 3-kinase (PI3K) regulates TLR-mediated cytokine release, but whether HIV infection influences PI3K signaling pathway and alters TLR4-mediated macrophage response has not been investigated. In the current study, surface TLR4 expression were similar but TLR4 activation (lipid A, 10 microg/ml) resulted in lower TNF-alpha release by HIV+ human macrophages compared with healthy cells. Pharmacological inhibition of PI3K (LY294002) normalized TNF-alpha release in HIV+ macrophages and augments ERK1/2 mitogen-activated protein kinase phosphorylation in response to lipid A. Importantly, HIV+ macrophages demonstrated increased constitutive phosphatidylinositol 3,4,5-trisphosphate formation, increased phosphorylation of downstream signaling molecules Akt and glycogen synthase kinase-3beta (GSK-3beta) at Ser9, and reduced PTEN protein expression. As a functional assessment of GSK-3beta phosphorylation, TLR4-mediated interleukin-10 release was significantly higher in HIV+ human macrophages compared with healthy cells. Incubation of human macrophages with exogenous HIV Nef protein induced phosphorylation of Akt and GSK-3beta (whereas phosphorylation was reduced by PI3K inhibition) and promoted interleukin-10 release. Taken together, these data demonstrate increased constitutive activation of the PI3K signaling pathway in HIV+ macrophages and support the concept that PI3K activation (by HIV proteins such as Nef) may contribute to reduced TLR4-mediated TNF-alpha release in HIV+ human macrophages and impair host cell response to infectious challenge.
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PMID:Constitutive activation of phosphatidylinositol 3-kinase signaling pathway down-regulates TLR4-mediated tumor necrosis factor-alpha release in alveolar macrophages from asymptomatic HIV-positive persons in vitro. 1882 50


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