Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10145 (IL-8)
 23,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To elucidate the role of Toll-like receptor 9 (TLR9) activation along with the intracellular signaling pathways triggered by CpG DNA in CD34+ cells, we investigated whether synthetic oligodeoxynucleotides (ODNs), containing unmethylated CpG motifs, could induce IL-8 expression in CD34+ cells through mitogen-activated protein kinase (MAPK) or nuclear factor-kappaB (NF-kappaB) pathway. We demonstrated evidence for the first time that CD34+ cells constitutively expressed TLR9. Exposure of the cells to CpG ODN resulted in a time- and dose-dependent increase of IL-8 expression, and activation of phosphorylated ERK1/2 and phosphorylated p38. In addition, CpG ODN stimulated AP-1, but not NF-kappaB, signals. Moreover, inhibitors of MAPK (U0126 and SB203580) significantly reduced the IL-8 production, while the inhibition of NF-kappaB (pyrrolidinedithiocarbamate and retrovirus containing dominant-negative IkappaB alpha plasmid) did not affect the IL-8 expression increased by CpG ODN. Moreover, co-stimulation with LPS and CpG synergistically up-regulates IL-8 in CD34+ cells. These results suggest that CpG DNA, acting on TLR9, activates CD34+ cells to express IL-8 through MAPK-dependent and NF-kappaB-independent pathways.
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PMID:CpG oligodeoxynucleotides induce IL-8 expression in CD34+ cells via mitogen-activated protein kinase-dependent and NF-kappaB-independent pathways. 1626 54

Celiac disease is a chronic inflammatory disease developing in genetically predisposed individuals. Ingested gliadin, the triggering agent of the disease, can cross the epithelial barrier and elicit a harmful T cell-mediated immune response. Dendritic cells (DC) are supposed to play a pivotal role in shaping the immune response. The direction of the immune response toward immunity or tolerance depends on the stage of maturation and the functional properties of the DC. DC become fully functional APC upon maturation by various stimuli. We investigated the effect of a peptic digest of gliadin on the maturation of human monocyte-derived DC. Stimulation of cells with gliadin, in contrast with other tested food proteins, led to enhanced expression of maturation markers (CD80, CD83, CD86, and HLA-DR molecules) and increased secretion of chemokines and cytokines (mainly of IL-6, IL-8, IL-10, TNF-alpha, growth-related oncogene, MCP-1, MCP-2, macrophage-derived chemokine, and RANTES). Maturation was accompanied by a greater capacity to stimulate proliferation of allogeneic T cells and significantly reduced endocytic activity. Furthermore, gliadin-induced phosphorylation of members of three MAPK families (ERK1/2, JNK, and p38 MAPK) was demonstrated. The largest contribution of p38 MAPK was confirmed using its inhibitor SB203580, which markedly down-regulated the gliadin-triggered up-regulation of maturation markers and cytokine production. Gliadin treatment also resulted in increased NF-kappaB/DNA binding activity of p50 and p65 subunits. Taken together, gliadin peptides can contribute to overcoming the stage of unresponsiveness of immature DC by inducing phenotypic and functional DC maturation, resulting in more efficient processing and presentation of gliadin peptides to specific T lymphocytes.
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PMID:Gliadin fragments induce phenotypic and functional maturation of human dendritic cells. 1627 65

Glycogen-synthase kinase-3 (GSK-3) and extracellular signal-regulated kinase (ERK) are critical downstream signaling proteins for the PI3-kinase/Akt and Ras/Raf/MEK-1 pathway, respectively, and regulate diverse cellular processes including embryonic development, cell differentiation and apoptosis. Here, we show that inhibition of GSK-3 using GSK-3 inhibitors or RNA interference (RNAi) significantly induced the phosphorylation of ERK1/2 in human colon cancer cell lines HT29 and Caco-2. Pretreatment with the PKCdelta-selective inhibitor rottlerin or transfection with PKCdelta siRNA attenuated the phosphorylation of ERK1/2 induced by the GSK-3 inhibitor SB-216763 and, furthermore, treatment with SB-216763 or transfection with GSK-3alpha and GSK-3beta siRNA increased PKCdelta activity, thus identifying a role for PKCdelta in the induction of ERK1/2 phosphorylation by GSK-3 inhibition. Treatment with SB-216763 increased expression of cyclooxygenase-2 (COX-2) and IL-8, which are downstream targets of ERK1/2 activation; this induction was abolished by MEK/ERK inhibition, suggesting GSK-3 inhibition induced COX-2 and IL-8 through ERK1/2 activation. The transcriptional induction of COX-2 and IL-8 by GSK-3 inhibition was further demonstrated by the increased COX-2 and IL-8 promoter activity after SB-216763 treatment or transfection with GSK-3alpha or GSK-3beta siRNA. Importantly, our findings identify GSK-3, acting through PKCdelta, as a negative regulator of ERK1/2, thus revealing a novel crosstalk mechanism between these critical signaling pathways.
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PMID:Glycogen synthase kinase-3 is a negative regulator of extracellular signal-regulated kinase. 1627 84

We investigated and compared the mechanisms by which two dust mite proteolytic allergens, Der p 1 and Der p 3, and a peptide agonist of proteinase-activated receptor 2 (PAR(2)AP) trigger interleukin (IL)-8 release from human pulmonary epithelial cells (A549). Although all three stimuli tested induced the up-regulation of IL-8 (mRNA and protein), the Der p 1-mediated signaling events did not exactly match those induced by PAR(2)AP and Der p 3. First, Der p 1 was less effective in stimulating IL-8 gene transcriptional activity than PAR(2)AP and Der p 3. Second, Der p 1-mediated IL-8 expression was mainly dependent on NF-kappaB, whereas Der p 3 and PAR(2)AP regulated IL-8 expression through the activation of both NF-kappaB and AP-1. Third, although all three MAP kinases, ERK1/2, p38, and JNK, were activated, Der p 1 induced IL-8 release exclusively via the ERK1/2 signaling pathway, whereas PAR(2)AP and Der p 3 also involved the other kinases. Fourth, in HeLa cells, Der p 1 was able to up-regulate IL-8 secretion independent of PAR(2) expression, and in contrast with PAR(2)AP and Der p 3, Der p 1 was unable to affect calcium signaling via PAR(2) in PAR(2)-expressing KNRK cells. Finally, cleavage by Der p 1 of a synthetic peptide representing the N-terminal activation-cleavage site of PAR(2) did not release a high potency activator of PAR(2) as does Der p 3. We conclude that Der p 1 (but not Der p 3)-induced IL-8 production in A549 epithelial cells is independent of PAR(2) activation.
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PMID:The house dust mite allergen Der p 1, unlike Der p 3, stimulates the expression of interleukin-8 in human airway epithelial cells via a proteinase-activated receptor-2-independent mechanism. 1629 28

Interleukin-8 (IL-8) is a key chemokine upregulated in various forms of intestinal inflammation, especially those induced by bacteria such as Clostridium difficile (C. difficile). Although interactions between different mucosal and submucosal cellular components have been reported, whether such interactions are involved in the regulation of IL-8 secretion during C. difficile infection is unknown. Moreover, whether the enteric nervous system, a major component of the submucosa, is involved in IL-8 secretion during an inflammatory challenge remains to be determined. In order to investigate mucosa/submucosa interactions that regulate IL-8 secretion, we co-cultured human intestinal mucosa and submucosa. In control condition, IL-8 secretion in co-culture was lower than the sum of the IL-8 secretion of both tissue layers cultured alone. Contrastingly, IL-8 secretion increased in co-culture after mucosal challenge with toxin B of C. difficile through an IL-1 beta-dependent pathway. Moreover, we observed that toxin B of C. difficile increased IL-8 immunoreactivity in submucosal enteric neurones in co-culture and in intact preparations of mucosa/submucosa, through an IL-1 beta-dependent pathway. IL-1 beta also increased IL-8 secretion and IL-8 mRNA expression in human neuronal cell lines (NT2-N and SH-SY5Y), through p38 and ERK1/2 MAP kinase-dependent pathways. Our results demonstrate that mucosa/submucosa interactions regulate IL-8 secretion during inflammatory processes in human through IL-1 beta-dependent pathways. Finally we observed that human submucosal neurones synthesize IL-8, whose production in neurones is induced by IL-1 beta via MAPK-dependent pathways.
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PMID:Human mucosa/submucosa interactions during intestinal inflammation: involvement of the enteric nervous system in interleukin-8 secretion. 1630 65

Interleukin-8 (IL-8) is a potent proinflammatory chemokine that plays an important role in inflammation by activating and recruiting neutrophils, lymphocytes, and eosinophils. To demonstrate the effect of intracellular Ca(2+) on IL-8 production and related signaling, we stimulated human mast cell line HMC-1 with either calcium ionophore A23187 or thapsigargin. Increase of intracellular Ca(2+) resulted in inducing IL-8 gene expression and protein secretion, and addition of EGTA or BAPTA/AM before Ca(2+) stimulation inhibited the induction of IL-8 production. Intracellular Ca(2+) triggered the activation of mitogen-activated protein kinase (MAPK) in HMC-1, especially p42 and p44 isoforms of extracellular signal-regulated kinase (ERK) and p38 MAPK, but not c-Jun N-terminal kinase (JNK). Pretreatment of MAPK inhibitors (PD98059 and SB203580) markedly blocked Ca(2+)-induced IL-8 production from cells, and anti-inflammatory drugs, such as dexamethasone and cyclosporin A, partially inhibited the activation of ERK1/2. We determined that increased Ca(2+) activates the nuclear translocation of the transcription factor NF-kappaB. NF-kappaB inhibitors blocked the ability of Ca(2+) to induce IL-8 production, and the activation of NF-kappaB was required for intracellular Ca(2+)-induced up-regulation of IL-8. These results suggest that increased intracellular Ca(2+) stimulated p38 and ERK1/2 MAPK signaling cascades result in NF-kappaB activation and IL-8 production in HMC-1 cells. This study is the first to identify the intracellular signaling pathways involved in the Ca(2+)-mediated up-regulation of IL-8 synthesis and release from HMC-1 cells.
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PMID:Involvement of mitogen-activated protein kinase and NF-kappaB activation in Ca2+-induced IL-8 production in human mast cells. 1634 28

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

Adipose tissue is a major secretory and endocrine active organ producing a variety of bioactive proteins that may regulate energy metabolism and insulin sensitivity. In several studies, we have already shown that adipocyte-secretory products induce skeletal muscle insulin resistance. However, the precise nature of these factors has remained elusive. Human adipocytes were found to secrete various cytokines including IL-6, IL-8, macrophage inflammatory protein-1alpha/beta, and monocyte chemotactic protein-1 (MCP-1). Among these candidates, MCP-1 alone impaired insulin signaling in skeletal muscle cells at doses similar to its physiological plasma concentrations (200 pg/ml), whereas IL-6, IL-8, and macrophage inflammatory protein-1beta were effective at very high concentrations only. In addition, MCP-1 significantly reduced insulin-stimulated glucose uptake in the myocytes. Expression analysis of chemokine receptors in skeletal muscle cells revealed the presence of chemokine CXC motif receptor 1/2 and chemokine CC motif receptor 1/2/4/5/10. The action of MCP-1 on insulin signaling in skeletal muscle cells occurs via ERK1/2 activation but does not involve activation of the nuclear factor kappaB pathway. In conclusion, our data show that adipocytes secrete various adipokines that may be involved in the negative cross-talk between adipose tissue and skeletal muscle. Human skeletal muscle cells are highly sensitive toward MCP-1, which impairs insulin signaling and glucose uptake at concentrations even below that found in the circulation. However, other cytokines that are released by adipocytes impair insulin action only at supraphysiological concentrations. Therefore, MCP-1 may represent a molecular link in the negative cross-talk between adipose tissue and skeletal muscle assigning a completely novel important role to MCP-1 besides inflammation.
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PMID:Monocyte chemotactic protein-1 is a potential player in the negative cross-talk between adipose tissue and skeletal muscle. 1643 61

Although Staphylococcus aureus is a major cause of pulmonary infection, the role played by this bacterium in the induction of inflammation of human airway epithelial cells (HAEC) is poorly understood. In this study, we investigated the inflammatory response of HAEC to S. aureus soluble virulence factors and demonstrate that the combination of a long-acting beta2-adrenergic receptor agonist (salmeterol) with a glucocorticoid (fluticasone propionate) has an anti-inflammatory effect on HAEC. First, we demonstrate increased expression at both the mRNA and protein levels of interleukin (IL)-8, IL-6, and tumor necrosis factor (TNF)-alpha following incubation of HAEC in the presence of S. aureus soluble virulence factors and the increase of 1) the free nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) activities and 2) the phosphorylated (P-) extracellular signal-regulated kinases 1 and 2 (ERK1/ERK2), the P-c-Jun NH2-terminal kinase (JNK), and the P-isoform-alpha of the NF-kappaB inhibitor (IkappaB alpha). Next, when HAEC were preincubated with the combination of salmeterol and fluticasone propionate, the inflammatory response of HAEC was markedly attenuated in that levels of IL-8, IL-6, TNF-alpha, NF-kappaB, AP-1, P-ERK1/ERK2, P-JNK, and P-IkappaB alpha decreased significantly. These data emphasize the deleterious effect of S. aureus soluble virulence factors and suggest that the combination of a beta2-adrenergic receptor agonist with a glucocorticoid may attenuate the associated airway epithelial inflammation.
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PMID:Downregulation by a long-acting beta2-adrenergic receptor agonist and corticosteroid of Staphylococcus aureus-induced airway epithelial inflammatory mediator production. 1648 15

IL-20 belongs to the IL-10 family and is involved in the pathogenesis of keratinocyte hyperproliferation in vivo. Endothelial cells express IL-20 receptors. To explore the function of IL-20 on endothelial cells, we treated human umbilical vein endothelial cells (HUVECs) and human microvascular endothelial cells (HMECs) with human IL-20 and analyzed its effect on endothelial cells. IL-20 induced proliferation of endothelial cells and the activity was specifically blocked by anti-human-IL-20 monoclonal antibody and soluble (s)IL-20 receptor (R)1 and sIL-20R2. An alternatively spliced variant of IL-20 was isolated and also was shown to induce proliferation of HUVECs and HMECs. Treatment of HUVECs with both IL-10 and IL-20 demonstrated that IL-10 antagonized the activity of IL-20 because it diminished IL-20-induced proliferation of HUVECs. IL-20 significantly induced HUVECs migration and vascular tube formation on Matrigel in vitro. In vivo, IL-20 also enhanced tumor angiogenesis. Incubation of IL-20 with HUVECs induced transcripts of bFGF, VEGF, MMP-2, MMP-9, and IL-8. Furthermore, incubation of HUVECs with IL-20 induced phosphorylation of ERK1/2, p38, and JNK. Thus, IL-20 is a pleiotropic cytokine and promotes angiogenesis.
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PMID:Interleukin-20 promotes angiogenesis in a direct and indirect manner. 1651 54


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