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IL-8 Expression (il-8 + expression)
Selected AbstractsActivation of the Nrf2/antioxidant response pathway increases IL-8 expressionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2005Xiaolan Zhang Abstract Oxidant stress can initiate or enhance inflammatory responses during tissue injury, possibly through activation of redox-sensitive chemokines. Because the transcription factor Nrf2 (NF-E2-related factor,2) is responsive to oxidative stress, and induces expression of cytoprotective and antioxidant genes that attenuate tissue injury, we postulated that Nrf2 may also regulate chemokine expression. To test this hypothesis, Nrf2 expression was directly increased in primary human kidney mesangial cells and aortic endothelial cells, or cell lines with an adenoviral construct, and the effects on the pro-inflammatory chemokine interleukin-8 (IL-8) were assessed. Nrf2 expression significantly increased IL-8 mRNA levels and protein secretion. Nrf2 caused only a weak induction of IL-8 transcription, but significantly increased the half-life of IL-8 mRNA. These data demonstrate that activation of the Nrf2/antioxidant response pathway induces expression of IL-8. The dominant mechanism of Nrf2-mediated IL-8 induction is through mRNA stabilization. Considering the evidence that Nrf2 activation is mainly cytoprotective, these observations raise the possibility that under certain circumstances IL-8 may serve an anti-inflammatory role and thereby contribute to the resolution of tissue injury. See accompanying commentary http://dx.doi.org/10.1002/eji.200535489 [source] The p38 mitogen-activated protein kinase regulates interleukin-1,-induced IL-8 expression via an effect on the IL-8 promoter in intestinal epithelial cellsIMMUNOLOGY, Issue 4 2003Kuljit Parhar Summary Several lines of evidence implicate the p38 mitogen-activated protein kinase (p38 MAPK) in the proinflammatory response to bacterial agents and cytokines. Equally, the transcription factor, nuclear factor (NF)-,B, is recognized to be a critical determinant of the inflammatory response in intestinal epithelial cells (IECs). However, the precise inter-relationship between the activation of p38 MAPK and activation of the transcription factor NF-,B in the intestinal epithelial cell (IEC) system, remains unknown. Here we show that interleukin (IL)-1, activates all three MAPKs in Caco-2 cells. The production of IL-8 and monocyte chemotactic protein 1 (MCP-1) was attenuated by 50% when these cells were preincubated with the p38 MAPK inhibitor, SB 203580. Further investigation of the NF-,B signalling system revealed that the inhibitory effect was independent of the phosphorylation and degradation of I,B,, the binding partner of NF-,B. This effect was also independent of the DNA binding of the p65 Rel A subunit, as well as transactivation, determined by an NF-,B luciferase construct, using both SB 203580 and dominant,negative p38 MAPK. Evaluation of IL-8 and MCP-1 RNA messages by reverse transcription,polymerase chain reaction (RT,PCR) revealed that the inhibitory effect of SB 203580 was associated with a reduction in this parameter. Using an IL-8,luciferase promoter construct, an effect of p38 upon its activation by both pharmacological and dominant,negative p38 construct co-transfection was demonstrated. It is concluded that p38 MAPK influences the expression of chemokines in intestinal epithelial cells, through an effect upon the activation of the chemokine promoter, and does not directly involve the activation of the transcription factor NF-,B. [source] Effect of natural commensal-origin DNA on toll-like receptor 9 (TLR9) signaling cascade, chemokine IL-8 expression, and barrier integritiy of polarized intestinal epithelial cellsINFLAMMATORY BOWEL DISEASES, Issue 3 2010Darab Ghadimi Abstract Background and Aim: The intestinal epithelium is constantly exposed to high levels of genetic material like bacterial DNA. Under normal physiological conditions, the intestinal epithelial monolayer as a formidable dynamic barrier with a high-polarity structure facilitates only a controlled and selective flux on components between the lumen and the underlining mucosa and even is able to facilitate structure-based macromolecules movement. The aim of this study was to test the effect of natural commensal-origin DNA on the TLR9 signaling cascade and the barrier integrity of polarized intestinal epithelial cells (IECs). Methods: Polarized HT-29 and T84 cells were treated with TNF-, in the presence or absence of DNA from Lactobacillus rhamnosus GG (LGG) and Bifidobacterium longum. TLR9 and interleukin-8 (IL-8) mRNA expression was assessed by semiquantitative and TaqMan real-time reverse-transcription polymerase chain reaction. Expression of TLR9 protein, degradation of inhibitor of kappa B alpha (I,B,), and p38 mitogen-activated protein kinase (p38 MAP) phosphorylation were assessed by Western blotting. To further reveal the role of TLR9 signaling, the TLR9 gene was silenced by siRNA. IL-8 secretion was measured by an enzyme-linked immunosorbent assay. Nuclear factor-kappa B (NF-,B) activity was assessed by the electrophoretic mobility shift assay (EMSA) and NF-,B-dependent luciferase reporter gene assays. As an indicator of tight junction formation and monolayer integrity of epithelial cell monolayers, transepithelial electrical resistance (TER) was repetitively monitored. Transmonolayer movement of natural commensal-origin DNA across monolayers was monitored using qRT-PCR and nested PCR based on bacterial 16S rRNA genes. Results: In response to apically applied natural commensal-origin DNA, polarized HT-29 and T84 cells enhanced expression of TLR9 in a specific manner, which was subsequently associated with attenuation of TNF-,-induced NF-,B activation and NF-,B-mediated IL-8 expression. TLR9 silencing abolished this inhibitory effect. Apically applied LGG DNA attenuated TNF-,-enhanced NF-,B activity by reducing I,B, degradation and p38 phosphorylation. LGG DNA did not decrease the TER but rather diminished the TNF-,-induced TER reduction. Translocation of natural commensal-origin DNA into basolateral compartments did not occur under tested conditions. Conclusions: Our study indicates that TLR9 signaling mediates, at least in part, the anti-inflammatory effects of natural commensal-origin DNA on the gut because TLR9 silencing abolished the inhibitory effect of natural commensal-origin DNA on TNF-,-induced IL-8 secretion in polarized IECs. The nature of the TLR9 agonist, the polarity of cells, and the tight junction integrity of IECs has to be taken into account in order to predict the outcome of TLR9 signaling. (Inflamm Bowel Dis 2010) [source] Localization of substance P-induced upregulated interleukin-8 expression in human dental pulp explantsINTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2008G. T.-J. Abstract Aim, To localize ex vivo expression of interleukin-8 (IL-8) induced by substance P (SP) in human dental pulps. Methodology, Intact caries-free, freshly extracted third molars (n = 20) were collected from patients (15,25 years old). The teeth were split and pulpal tissue was obtained and stored in Dulbecco's modified Eagle medium. Human dental pulp tissue explants were stimulated with SP. Expression of IL-8 in pulp explants was detected and localized by immunohistochemistry. Results, Moderated IL-8 immunoreactivities were detected mainly in the cell-rich zone in pulp tissues 12 h after tumour necrosis factor alpha (TNF-,) stimulation (positive controls), whereas only weak IL-8 expression was observed in tissues stimulated with SP at the same time interval. These data did not differ from those in negative controls. Increased IL-8 expression in pulp explants after 24 h of SP stimulation was noted compared with negative controls and located in fibroblast-like cells, blood vessel-associated cells and extracellular matrix in the central zone and cell-rich zone of pulp explants. Tissues stimulated with TNF-, for 24 h (positive controls) revealed weak IL-8 immunoreactivities with altered cell morphology. Conclusions, Substance P induces IL-8 expression and was located in fibroblast-like pulp cells, blood vessel-associated cells and extracellular matrix of human dental explants. These data support the hypothesis that neuropeptide (SP) coordinates the modulation of pulpal inflammation via up-regulating chemokine IL-8. [source] IL-1, induces stabilization of IL-8 mRNA in malignant breast cancer cells via the 3, untranslated region: Involvement of divergent RNA-binding factors HuR, KSRP and TIAR,INTERNATIONAL JOURNAL OF CANCER, Issue 6 2005Esther A. Suswam Abstract IL-8 plays an integral role in promoting the malignant phenotype in breast cancer, and its production is directly influenced by inflammatory cytokines in the tumor microenvironment. Here, we show that activation of IL-1, receptors on malignant HS578t and MDA-MB-231 breast cancer cells strongly induces IL-8 expression and that RNA stabilization is persistently activated at least 12,24 hr after stimulation. SB 203580 and rapamycin reversed the RNA stabilization effect of IL-1, in a dose-dependent manner, suggesting involvement of the p38/MAP kinase and mTOR pathways. A luciferase reporter assay indicated that the stabilization effect was dependent on cis elements in the 3,-untranslated region (UTR) of the IL-8 transcript. By UV cross-linking, we identified multiple cellular factors that interact with the IL-8 3,UTR, ranging 34,76 kDa. Immunoprecipitation analysis indicated that HuR, KSRP and TIAR bound to one or more loci in the 3,UTR. While the cross-linking patterns were similar, quantitative immunoprecipitation of native IL-8 RNA from IL-1,-stimulated cytoplasmic extract revealed a 20-fold greater association of transcript with the stabilizing factor HuR vs. the destabilizing factor KSRP. In conclusion, IL-1, is a potent cytokine stimulus for IL-8 RNA stabilization in breast cancer cells, possibly by enhanced binding of cytoplasmic HuR to the 3,UTR. Published 2004 Wiley-Liss, Inc. [source] Hepatocyte growth factor induces hypoxia-related interleukin-8 expression in lung adenocarcinoma cellsMOLECULAR CARCINOGENESIS, Issue 7 2009Yung-Yen Chiang Abstract Rapid growth of cancer cells often creates insufficient supply of oxygen and nutrients in the tumour nest. The frequent detection of hypoxia-inducible factor (HIF) and interleukin-8 (IL-8) in afflicted tissues suggests that IL-8 expression could be associated with elevated levels of HIF. Recently, we found that hypoxia also upregulated the expression of hepatocyte growth factor (HGF) in lung adenocarcinoma (LAD) cells. However, the relationship between HGF and IL-8 has not been investigated in LAD cells. In this study, we found that HGF induced IL-8 expression in LAD. Interestingly, hypoxia also increased the level of prostaglandin F2, (PGF2,), a product of dihydrodiol dehydrogenase (DDH). When expression of DDH was suppressed by siRNA, the levels of PGF2,, HGF and IL-8 were reduced; however, their levels returned to normal after DDH was reintroduced. These data suggest that hypoxia induces biosynthesis of PGF2,, which then activates HGF and IL-8 expression. The results provide a reasonable explanation of how PGF2,, HGF and IL-8 exert their effects on cancer cell metastasis. © 2009 Wiley-Liss, Inc. [source] Quantitative cytokine gene expression in CF airway,PEDIATRIC PULMONOLOGY, Issue 5 2004Marianne S. Muhlebach MD Abstract Bronchoalveolar lavage fluid (BALF) in cystic fibrosis (CF) shows increased inflammation, which could be due to abnormal cytokine regulation. Bronchial epithelial cells and migratory inflammatory cells produce these cytokines, but few quantitative in vivo data are available comparing young CF patients with controls. We hypothesized that IL-8 mRNA abundance was higher in young CF vs. non-CF disease control patients in lung epithelium and inflammatory cells. Bronchial epithelial cells (BEC) were obtained by brush biopsy, and airway inflammatory cells (BALFC) by bronchoalveolar lavage, in 17 CF and 21 non-CF patients <5 years old undergoing clinically indicated bronchoscopy. Cellular mRNA expression was quantified by real-time PCR and normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Abundance of IL-8/GAPDH in BEC was significantly higher in CF (14.8,±,3.3) than non-CF (4.2,±,0.6) samples, and this difference was also significant when patients were stratified according to infection. In BALFC, the difference in IL-8 expression did not reach statistical significance: CF (17.1,±,6.5) vs. non-CF (6.8,±,1.9), but BALF cell number/ml was significantly higher in CF. IL-10 mRNA was very low in all samples, without showing a decrease in CF vs. non-CF patients. We conclude that early in the disease, IL-8 mRNA expression in BEC is increased in CF in vivo. Although IL-8 mRNA in migratory cells was not significantly higher in CF, these cells may still contribute to elevated IL-8 in airway secretions, secondary to increased cell density in BALF. Pediatr Pulmonol. 2004; 37:393,399. © 2004 Wiely-Liss, Inc. [source] N -acetyl- L -cysteine inhibits bleomycin-induced interleukin-8 secretion by bronchial epithelial cellsRESPIROLOGY, Issue 4 2000Yasuhiro Gon Objective: Bleomycin (BLM) has proven effective for the treatment of cancers, but the most serious dose-limiting side-effect is the development of pulmonary toxicity. Although the precise mechanism in the pathogenesis of BLM-induced lung injury has not been determined, oxygen radicals and neutrophils are indicated to play a key role in it. Interleukin-8 (IL-8) is thought to be an important mediator of the pathogenesis of acute lung injury. Methodology: The IL-8 production from bronchial epithelial cell line, BEAS-2B cells was measured by enzyme-linked immunosorbent assays for IL-8. Results: The concentrations of IL-8 were reportedly elevated in BLM-induced lung injury, suggesting the involvement of IL-8 in the pathogenesis of BLM-induced lung injury. In the present study, we showed that BLM induced the expression of IL-8 protein and mRNA in BEAS-2B cells, and N -acetyl- L -cysteine (NAC) inhibited IL-8 expression. In addition, the structurally unrelated anti-oxidant, pyrrolidine dithiocarbamate (PDTC) also effectively inhibited BLM-induced IL-8 production. Conclusion: These results suggest that anti-oxidant-sensitive mechanism might be involved in the inhibition of IL-8 secretion by BLM-stimulated bronchial epithelial cells and that NAC might be useful for the treatment of BLM-induced lung injury. [source] ORIGINAL ARTICLE: TNF, Gene Silencing Reduced Lipopolysaccharide-Promoted Proliferation of Endometriotic Stromal CellsAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 4 2009Ayako Miyamoto Problem, We previously reported that lipopolysaccharide (LPS)-promoted endometriotic stromal cell (ESC) proliferation by inducing TNF, production. The aim of this study was to investigate the efficacy of TNF, gene silencing on LPS-treated ESCs. Method of study, Endometriotic stromal cells (ESCs) and endometrial stromal cells (ESCs) (EMSCs) were obtained from ovarian chocolate cysts and uterine myoma, respectively. Using PCR array, LPS-induced gene expression profiling after transfection of TNF, siRNA into ESCs was performed. Down-regulated genes by TNF, silencing were examined using real-time RT-PCR. Effect of TNF, silencing was examined using ELISA and BrdU incorporation, respectively. Results, In PCR array, TNF, silencing in ESCs repressed LPS-induced expression of cIAP2 and IL-8, NF,B pathway responsive genes. After adding LPS, the levels of cIAP2 and IL-8 expression in ESCs were higher compared with those in EMSCs. TNF, silencing attenuated the LPS-induced ESC proliferation. Conclusion, Tumor necrosis factor , may be involved in cell proliferation of endometriotic tissues. [source] Activation of NF-,B and IL-8 by Yersinia enterocolitica invasin protein is conferred by engagement of Rac1 and MAP kinase cascadesCELLULAR MICROBIOLOGY, Issue 12 2003Guntram A. Grassl Summary Yersinia enterocolitica triggers activation of the nuclear factor (NF)-,B and production of the proinflammatory chemokine interleukin (IL)-8 in intestinal epithelial cells. This activation is due to adhesion of the bacteria via their outer membrane protein invasin to the host cells. Using Clostridium difficile toxins that specifically inactivate small GTPases, and transfection of inhibitory proteins of the Rho-GTPases, we demonstrate that Rac1, but not Cdc42 or Rho, is required for activation of NF-,B by invasin. Invasin activated the mitogen activated protein kinases (MAPK) p38 and c-Jun N-terminal protein kinase (JNK) but not extracellular signal regulated kinase (ERK). The functional relevance of these pathways for invasin-mediated IL-8 expression was assessed by protein kinase inhibitors and dominant-negative kinase mutants. While NF-,B and JNK contribute to IL-8 transcription, p38 MAPK also acts through stabilization of IL-8 mRNA, as confirmed by quantitative RT-PCR and electrophoretic mobility shift assays. Transfection experiments with I-,B kinase (IKK)1 and IKK2 mutants indicate that the release of NF-,B from its cytoplasmic inhibitor I-,B and its translocation into the nucleus is mediated by these kinases. Our data identify Rac1 as a key intermediate in invasin-triggered IL-8 synthesis and demonstrate that maximum IL-8 induction involves several MAP kinase cascades. [source] Montelukast inhibits tumour necrosis factor-,-mediated interleukin-8 expression through inhibition of nuclear factor-,B p65-associated histone acetyltransferase activityCLINICAL & EXPERIMENTAL ALLERGY, Issue 5 2008F. Tahan Summary Background Montelukast is a potent cysteinyl leukotriene-1 receptor antagonist possessing some anti-inflammatory effects although the molecular mechanism of these anti-inflammatory effects is unknown. In this study, we aimed to investigate the effect of montelukast on nuclear factor (NF)-,B-associated histone acetylation activity in phorbol myristate acetate (PMA)-differentiated U937 cells. Methods We examined the inhibitory effects of montelukast on TNF-,-induced IL-8 production in PMA-differentiated U-937 cells. U-937 cells were exposed to PMA (50 ng/mL) for 48 h to allow differentiation to macrophages. Macrophages were then exposed to TNF-, (10 ng/mL) in the presence or absence of montelukast (0.01,10 ,m) for 24 h. After this time, the concentration of IL-8 in the culture supernatant was measured by sandwich-type ELISA kit. The effect of signalling pathways on TNF-,-induced IL-8 release was examined pharmacologically using selective NF-,B/IKK2 (AS602868, 3 ,m), (PD98059, 10 ,m) and p38 mitogen activated protein kinase (MAPK) (SB203580, 1 ,m) inhibitors. NF-,B DNA binding activity was measured by a DNA-binding ELISA-based assay. NF-,B-p65-associated histone acetyltransferase (HAT) activity was measured by immunoprecipitation linked to commercial flourescent HAT. Results TNF-,-induced IL-8 release was suppressed by an NF-,B inhibitor but not by MEK or p38 MAPK inhibitors. Montelukast induced a concentration-dependent inhibition of TNF-,-induced IL-8 release and mRNA expression that reached a plateau at 0.1 ,m without affecting cell viability. Montelukast did not affect NF-,B p65 activation as measured by DNA binding but suppressed NF-,B p65-associated HAT activity. Conclusion Montelukast inhibits TNF-,-stimulated IL-8 expression through changes in NF-,B p65-associated HAT activity. Drugs targeting these enzymes may enhance the anti-inflammatory actions of montelukast. [source] Eosinophil granule-derived major basic protein induces IL-8 expression in human intestinal myofibroblastsCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2000G. T. Furuta Eosinophil infiltration occurs in a variety of allergic and inflammatory diseases. The release of preformed mediators from eosinophils may contribute to inflammatory responses. We investigated the ability of eosinophil-derived major basic protein and eosinophil-derived neurotoxin to stimulate production of IL-8 from intestinal myofibroblasts. Intestinal myofibroblasts (18-Co cells) were incubated with major basic protein, eosinophil-derived neurotoxin, or a synthetic analogue of major basic protein, poly- l -arginine. Immunoreactive IL-8 was measured by ELISA and IL-8 mRNA levels were analysed by Northern blot or reverse transcription-polymerase chain assay. Major basic protein induced IL-8 mRNA production and release of significant levels of IL-8 immunoreactive protein. By contrast, eosinophil-derived neurotoxin stimulated little IL-8 release. The induction of IL-8 mRNA by poly- l -arginine was significantly inhibited by actinomycin D. These findings demonstrate a novel interaction between eosinophils and intestinal fibroblasts that may be involved in the pathogenesis of diseases associated with tissue eosinophilia. [source] | ||||||||||||||||||||||