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IL-8 Release (il-8 + release)
Selected AbstractsCharacterization of epithelial IL-8 response to inflammatory bowel disease mucosal E. coli and its inhibition by mesalamine,INFLAMMATORY BOWEL DISEASES, Issue 2 2008Sreedhar Subramanian MD Abstract Background: Mucosally adherent E. coli are found in inflammatory bowel disease (IBD) and colon cancer. They promote release of the proinflammatory cytokine interleukin-8 (IL-8). We explored mechanisms for this release and its inhibition by drugs. Methods: IL-8 release from colon epithelial cells in response to mucosal E. coli isolates from IBD, colon cancer, and controls was characterized at the cellular and molecular level. Results: IL-8 response of HT29 cells was greater with Crohn's disease (689 ± 298 [mean ± SD] pg IL-8/mL at 4 hours, n = 7) and colon cancer isolates (532 ± 415 pg/mL, n = 14) than with ulcerative colitis (236 ± 58 pg/mL, n = 6) or control isolates (236 ± 100 pg/mL, n = 6, P < 0.0001). Bacterial supernatants contained shed flagellin that triggered IL-8 release. For whole bacteria the IL-8 response to E. coli that agglutinate red blood cells (548 ± 428 pg IL-8/mL, n = 16), a function that correlates with epithelial invasion, was greater than for nonhemagglutinators (281 ± 253 pg/mL, n = 17; P < 0.0001). This was particularly marked among E. coli that, although flagellate, could not release IL-8 from TLR5-transfected HEK293 cells. IL-8 release was mediated by extracellular-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) and inhibited by mesalamine, but not hydrocortisone, at therapeutic concentrations. Conclusions: Mucosa-associated E. coli shed flagellin that elicits epithelial IL-8 release but this may only become relevant when the mucosal barrier is weakened to expose basolateral TLR5. Adherent and invasive IBD and colon cancer E. coli isolates also elicit a flagellin-independent IL-8 response that may be relevant when the mucosal barrier is intact. The IL-8 release is MAPK-dependent and inhibited by mesalamine. (Inflamm Bowel Dis 2007) [source] Osteoblast-Derived TGF-,1 Stimulates IL-8 Release Through AP-1 and NF-,B in Human Cancer Cells,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2008Yi-Chin Fong Abstract Introduction: The bone marrow microenvironment is further enriched by growth factors released during osteoclastic bone resorption. It has been reported that the chemokine interleukin (IL)-8 is a potent and direct activator of osteoclastic differentiation and bone resorption. However, the effect of bone-derived growth factors on the IL-8 production in human cancer cells and the promotion of osteoclastogenesis are largely unknown. The aim of this study was to investigate whether osteoblast-derived TGF-,1 is associated with osteolytic bone diseases. Materials and Methods: IL-8 mRNA levels were measured using RT-PCR analysis. MAPK phosphorylation was examined using the Western blot method. siRNA was used to inhibit the expression of TGF-,1, BMP-2, and IGF-1. DNA affinity protein-binding assay and chromatin immunoprecipitation assays were used to study in vitro and in vivo binding of c- fos, c- jun, p65, and p50 to the IL-8 promoter. A transient transfection protocol was used to examine IL-8, NF-,B, and activator protein (AP)-1 activity. Results: Osteoblast conditioned medium (OBCM) induced activation of IL-8, AP-1, and NF-,B promoter in human cancer cells. Osteoblasts were transfected with TGF-,1, BMP-2, or IGF-1 small interfering RNA, and the medium was collected after 48 h. TGF-,1 but not BMP-2 or IGF-1 siRNA inhibited OBCM-induced IL-8 release in human cancer cells. In addition, TGF-,1 also directly induced IL-8 release in human cancer cells. Activation of AP-1 and NF-,B DNA-protein binding and MAPKs after TGF-,1 treatment was shown, and TGF-,1,induced IL-8 promoter activity was inhibited by the specific inhibitors of MAPK cascades. Conclusions: In this study, we provide evidence to show that the osteoblasts release growth factors, including TGF-,1, BMP-2, and IGF-1. TGF-,1 is the major contributor to the activation of extracellular signal-related kinase (ERK), p38, and c-Jun N-terminal kinase (JNK), leading to the activation of AP-1 and NF-,B on the IL-8 promoter and initiation of IL-8 mRNA and protein release, thereby promoting osteoclastogenesis. [source] Glucocorticoid-induced leucine zipper is an endogenous antiinflammatory mediator in arthritisARTHRITIS & RHEUMATISM, Issue 9 2010Elaine Beaulieu Objective Glucocorticoid-induced leucine zipper (GILZ) is a glucocorticoid-induced protein, the reported molecular interactions of which suggest that it functions to inhibit inflammation. However, the role of endogenous GILZ in the regulation of inflammation in vivo has not been established. This study was undertaken to examine the expression and function of GILZ in vivo in collagen-induced arthritis (CIA), a murine model of rheumatoid arthritis (RA), and in RA synoviocytes. Methods GILZ expression was detected in mouse and human synovium by immunohistochemistry and in cultured cells by real-time polymerase chain reaction and permeabilization flow cytometry. GILZ function was assessed in vivo by small interfering RNA (siRNA) silencing using cationic liposome,encapsulated GILZ or control nontargeting siRNA and was assessed in vitro using transient overexpression. Results GILZ was readily detectable in the synovium of mice with CIA and was up-regulated by therapeutic doses of glucocorticoids. Depleting GILZ expression in vivo increased the clinical and histologic severity of CIA and increased synovial expression of tumor necrosis factor and interleukin-1 (IL-1), without affecting the levels of circulating cytokines or anticollagen antibodies. GILZ was highly expressed in the synovium of patients with active RA and in cultured RA synovial fibroblasts, and GILZ overexpression in synovial fibroblasts inhibited IL-6 and IL-8 release. Conclusion Our findings indicate that GILZ functions as an endogenous inhibitor of chronic inflammation via effects on cytokine expression and suggest that local modulation of GILZ expression could be a beneficial therapeutic strategy. [source] Changes in IL-8 release and intracellular content in DMSO-differentiated HL-60 cells after treatment with 4-hydroxynonenalCELL BIOCHEMISTRY AND FUNCTION, Issue 5 2008Marina Maggiora Abstract 4-Hydroxynonenal (HNE), a chemotactic aldehyde produced by lipid peroxidation, has been shown to trigger exocytosis in HL-60 cells induced to differentiate toward the granulocytic cell line by DMSO. In this work we studied HNE effects on the intracellular content of IL-8 and its release in DMSO-differentiated HL-60 cells. Cell incubation at 37°C in the presence of 0.1,µM HNE induced a significant increase of IL-8 release after 30,min; the degree of HNE-induced IL-8 secretion became quite strong after 1,h, whereas the intracellular content showed no statistically significant changes. By contrast, 1,µM HNE induced a low decrease of the chemokine release; however, the used HNE concentrations failed to increase the release of lactate dehydrogenase (LDH), a test used to assay cell viability. The addition of 0.1,µM IL-8 to DMSO-differentiated HL-60 cells induced a strong increase of exocytosis, measured by , -glucuronidase secretion. Exocytosis stimulation by IL-8 was much higher than that given by the aldehyde; the addition of various HNE concentrations to cells incubated in the presence of IL-8 decreased the secretion given by the cytokine alone. However, HNE-induced exocytosis was likely to be a direct action of the aldehyde and was not mediated through the stimulation of IL-8 release since HNE was unable to modify IL-8 secretion during the short time of 10,min used in the exocytosis assay. Copyright © 2008 John Wiley & Sons, Ltd. [source] Interaction of cblA/adhesin-positive Burkholderia cepacia with squamous epitheliumCELLULAR MICROBIOLOGY, Issue 2 2002Umadevi Sajjan Summary A highly transmissible strain of Burkholderia cepacia from genomovar III carries the cable pilin gene, expresses the 22 kDa adhesin (cblA+ve/Adh +ve), binds to cytokeratin 13 (CK13) and is invasive. CK13 is expressed abundantly in the airway epithelia of cystic fibrosis (CF) patients. We have now investigated whether binding of cblA+ve/Adh +ve B. cepacia to CK13 potentiates bacterial invasion and epithelial damage using bronchial epithelial cell cultures differentiated into either squamous (CK13-enriched) or mucociliary (CK13-deficient) epithelia. Three different B. cepacia isolates (cblA+ve/Adh +ve, cblA+ve/Adh ,ve and cblA,ve/Adh ,ve) showed minimal binding to mucociliary cultures, and did not invade or cause cell damage. In contrast, the cblA+ve/Adh +ve isolate, but not others, bound to CK13-expressing cells in squamous cultures, caused cytotoxicity and stimulated IL-8 release within 2 h. By 24 h, this isolate invaded and migrated across the squamous culture, causing moderate to severe epithelial damage. A specific antiadhesin antibody, which blocked the initial binding of the cblA+ve/Adh +ve isolate to CK13, significantly inhibited all the pathologic effects. Transmission electron microscopy of squamous cultures incubated with the cblA+ve/Adh +ve isolate, revealed bacteria on the surface surrounded by filopodia by 2 h, and within the cells in membrane-bound vesicles by 24 h. Bacteria were also observed free in the cytoplasm, surrounded by intermediate filaments containing CK13. These findings suggest that binding of B. cepacia to CK13 is an important initial event and that it promotes bacterial invasion and epithelial damage. [source] Rhinovirus infection and house dust mite exposure synergize in inducing bronchial epithelial cell interleukin-8 releaseCLINICAL & EXPERIMENTAL ALLERGY, Issue 10 2008A. Bossios Summary Background Human rhinoviruses (HRVs) and house dust mites (HDMs) are among the most common environmental factors able to induce airway inflammation in asthma. Although epidemiological studies suggest that they also synergize in inducing asthma exacerbations, there is no experimental evidence to support this, nor any information on the possible mechanisms involved. Objective To investigate their interaction on the induction of airway epithelial inflammatory responses in vitro. Methods BEAS-2B cells were exposed to activated HDM Dermatophagoides pteronyssinus major allergen I (Der p I), HRVs (HRV1b or HRV16) or both in different sequences. IL-8/CXCL8 release, intercellular adhesion molecule (ICAM)-1 surface expression and nuclear factor ,B (NF-,B) translocation were evaluated. Complementary, primary human bronchial epithelial cells (HBECs) exposed to both Der p I and RVs and IL-8, IL-6, IFN-,-induced protein (IP)-10/CXCL10, IFN-,1/IL-29, regulated upon activation normal T lymphocyte expressed and secreted (RANTES)/CCL5 release were measured. Results RV and Der p I up-regulated IL-8 release, ICAM-1 expression and NF-,B translocation in BEAS-2B cells. Simultaneous exposure to both factors, as well as when cells were initially exposed to HRV and then to Der p I, resulted in further induction of IL-8 in a synergistic manner. Synergism was not observed when cells were initially exposed to Der p I and then to HRV. This was the pattern in ICAM-1 induction although the phenomenon was not synergistic. Concurrent exposure induced an early synergistic NF-,B translocation induction, differentiating with time, partly explaining the above observation. In HBECs, both HRV and Der p I induced IL-8, IL-6, IL-29 and IP-10, while RANTES was induced only by HRV. Synergistic induction was observed only in IL-8. Conclusion HRV and enzymatically active Der p I can act synergistically in the induction of bronchial epithelial IL-8 release, when HRV infection precedes or is concurrent with Der p I exposure. Such a synergy may represent an important mechanism in virus-induced asthma exacerbations. [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] Suppression of lipopolysaccharide- and tumour necrosis factor-,-induced interleukin (IL)-8 expression by glucocorticoids involves changes in IL-8 promoter acetylationCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2007L. G. Tsaprouni Summary There is accumulating evidence that the transrepressional effect of glucocorticoids in down-regulating proinflammatory gene expression might be regulated by an action on histone acetylation. To investigate this, we studied the effect of two glucocorticoids (dexamethasone and triamcinolone acetonide) on reducing lipopolysaccharide (LPS)- and tumour necrosis factor (TNF)-,-induced interleukin (IL)-8 release in a monocytic cell line and two lymphocytic cell lines (HUT-78 and Jurkat). The effect of the histone deacetylase inhibitor trichostatin A (TSA) on LPS- and TNF-,-induced IL-8 release and its repression by glucocorticoids was also examined. LPS and TNF-, induced IL-8 release in all three cell lines and this induction was inhibited by both dexamethasone and triamcinolone. Pretreatment of cells with TSA enhanced basal and LPS- and TNF,-stimulated IL-8 release in all three cell lines. TSA also attenuated the inhibitory effect of glucocorticoids on stimulated IL-8 release. Chromatin immunoprecipitation assays confirmed that LPS and TNF-, enhanced histone acetylation at the IL-8 promoter and that this was inhibited by triamcinolone in all three cell types. Changes in histone acetylation at the IL-8 are important in its regulation by proinflammatory and anti-inflammatory agents, and modulation of this activity may have therapeutic potential in inflammatory conditions. [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] | |||||||||||||