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)

Interleukin-8 (IL-8) is a potent chemotactic factor for neutrophils and T lymphocytes. Various reagents such as lectins, mitogens, IL-1, TNF, induce IL-8 production in a wide range of cells and tissues. The IL-8 gene is known to be activated by AP-1, NF-kB like factor and C/EBP like factor, but the relative importance of these transcriptional factors varies from cell to cell. Two types of human IL-8 receptor cDNA have recently been cloned. Both are G-protein coupled receptors and the amino acid sequences are highly homologous. Other members of the IL-8 family, such as GRO/MGSA and MIP2, bind to IL-8 receptors, and the receptors of other chemoattractants such as fMLP and C5a, show high homology to the IL-8 receptors.
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PMID:[Function, molecular structure and gene expression of IL-8]. 143 73

Our previous studies in human monocytes have demonstrated that interleukin (IL)-10 inhibits lipopolysaccharide (LPS)-stimulated production of inflammatory cytokines, IL-1 beta, IL-6, IL-8, and tumor necrosis factor (TNF)-alpha by blocking gene transcription. Using electrophoretic mobility shift assays (EMSA), we now show that, in monocytes stimulated with LPS or TNF alpha, IL-10 inhibits nuclear stimulation of nuclear factor kappa B (NF kappa B), a transcription factor involved in the expression of inflammatory cytokine genes. Several other transcription factors including NF-IL-6, AP-1, AP-2, GR, CREB, Oct-1, and Sp-1 are not affected by IL-10. This selective inhibition by IL-10 of NF kappa B activation occurs rapidly and in a dose-dependent manner and correlates well with IL-10's cytokine synthesis inhibitory activity in terms of both kinetics and dose responsiveness. Furthermore, compounds such as tosylphenylalanyl chloromethyl ketone and pyrrolidinedithiocarbamate that are known to selectively inhibit NF kappa B activation block cytokine gene transcription in LPS-stimulated monocytes. Taken together, these results suggest that inhibition of NF kappa B activation may be an important mechanism for IL-10 suppression of cytokine gene transcription in human monocytes. IL-4, another cytokine that inhibits cytokine mRNA accumulation in monocytes, shows little inhibitory effect on LPS-induced NF kappa B activation. Further examination reveals that, unlike IL-10, IL-4 enhances mRNA degradation and does not suppress cytokine gene transcription. These data indicate that IL-10 and IL-4 inhibit cytokine production by different mechanisms.
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PMID:Interleukin (IL)-10 inhibits nuclear factor kappa B (NF kappa B) activation in human monocytes. IL-10 and IL-4 suppress cytokine synthesis by different mechanisms. 772 85

A glucocorticoid, dexamethasone, inhibited the production of a leukocyte chemotactic cytokine, interleukin 8 (IL-8), as well as mRNA expression by a glioblastoma cell line, T98G, stimulated with interleukin 1 (IL-1). Dexamethasone also inhibited IL-8 promoter-driven chloramphenicol acetyltransferase (CAT) activities induced by IL-1, suggesting that dexamethasone inhibited IL-8 production mainly at the transcriptional level. Moreover, CAT assay revealed that the nuclear factor-kappa B (NF-kappa B) binding site was the crucial cis-element required for conferring IL-1 responsiveness in conjunction with the CCAAT enhancer binding protein/nuclear factor-IL-6 (NF-IL6) and/or the AP-1 binding site(s). Mutation of either the AP-1 or NF-IL6 binding site did not abolish IL-8 gene repression by dexamethasone, suggesting that these sites were not targets for dexamethasone. Trimerized kappa B sequence in the IL-8 gene was enough for conferring the induction by IL-1 and inhibition by dexamethasone of CAT activity. Finally, dexamethasone diminished the IL-1-induced formation of NF-kappa B complexes, which were identified immunochemically to consist of p50 and p65, without reducing the amount of translocated factors. Collectively, dexamethasone interfered with the binding of the most essential transcription factor, NF-kappa B, to its cognate cis-element, thereby suppressing the transcription of IL-8 gene.
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PMID:Novel mechanism of glucocorticoid-mediated gene repression. Nuclear factor-kappa B is target for glucocorticoid-mediated interleukin 8 gene repression. 817 59

The regulation of IL-6 mRNA expression was studied in human blood monocytes and in the human epidermoid carcinoma cell line HEp-2. In human monocytes phorbol-12-myristate 13-acetate (PMA) did not induce IL-6 but it increased IL-1 beta and IL-8 mRNA levels. Furthermore, in monocytes, protein kinase C (PKC) activation by PMA even reduced IL-1-induced IL-6 mRNA, and IL-1-induced IL-6 synthesis was increased by the PKC inhibitor staurosporine. IL-6 synthesis in HEp-2 cells was induced by IL-1, PMA, and calcium ionophore A 23187 but not by dibutyryl-cAMP. PMA-, but not IL-1-induced IL-6 synthesis in HEp-2 cells was inhibited by staurosporine. PMA pretreatment of HEp-2 cells abolished PMA-induced IL-6 but the IL-1 effect was not reduced. These data indicate that IL-6 can be induced by a PKC-independent pathway in monocytes and HEp-2 cells. In monocytes PKC activation does not induce IL-6 and PMA interferes with the IL-1 effect. Transcription factors known to be involved with the regulation of IL-6 expression were studied by gel retardation assays. NF-IL-6 and AP-1 activity were constitutively expressed in monocytes and HEp-2 cells under conditions where IL-6 mRNA was not detectable and levels did not change in response to stimulation by IL-1 or PMA. In contrast, NF-kB was increased by both IL-1 and PMA, but only the effect of PMA, and not that of IL-1, was inhibited by staurosporine. In summary, these results show tissue-specific differences in the regulation of IL-6 expression. Induction of IL-6 in monocytes is PKC independent. In the epithelial cell line HEp-2 IL-6 is inducible by PKC as well as by a PKC-independent pathway.
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PMID:Regulation of interleukin-6 (IL-6) expression: evidence for a tissue-specific role of protein kinase C. 824 77

Adenosine agonists inhibit TNF-alpha production in macrophage and monocytes, but the mechanism is unknown. Therefore, we studied the human macrophage cell line U937 to determine the adenosine receptor subtypes responsible and the intracellular signaling mechanisms involved. The A1/A3 agonist N6-(4-amino-3-iodobenzyl)adenosine (I-ABA) decreased LPS-stimulated TNF-alpha protein production by 79 +/- 5% (p = 0.003). The mechanism was pretranslational, as adenosine receptor stimulation caused a marked decrease in TNF-alpha mRNA. IL-1 beta, IL-6, and IL-8 mRNA were not changed by adenosine agonists. The rank order of agonists as TNF-alpha inhibitors suggested that the A3 receptor might be involved (N6-(3-iodobenzyl)-9-[5-(methylcarbamoyl)-beta-D-ribofuranosyl] adenosine > 2-chloroadenosine > or = I-ABA > N6 benzyl 5'-N-ethylcarboxamidoadenosine (NECA) > NECA > CGS21680 > N6-cyclohexyladenosine), and this was supported by the fact that a mixed A1/A3 antagonist (xanthine amine congener) reversed the effect, whereas A1-specific (1,3-dipropyl-8-cyclopentylxanthine) and A2-specific (3,7-dimethyl-1-propargylxanthine) antagonists did not. Receptor signaling did not involve cAMP or protein kinase A, nor did it alter the activation and binding characteristics of the transcription factor NF-kappa B. However, the composition of the AP-1 transcription complex was altered by I-ABA. These data suggest that stimulation of the A3 adenosine receptor can alter the cytokine milieu by decreasing TNF-alpha. Adenosine agonists or adenosine regulating agents have potential therapeutic uses in acute and chronic inflammatory diseases.
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PMID:Inhibition of TNF-alpha expression by adenosine: role of A3 adenosine receptors. 861 70

Interleukin-8 (IL-8), a potent neutrophil chemotactic peptide that elicits pleiotropic biological effects is secreted in large amounts by normal human osteoblastic and bone marrow osteoprogenitor stromal (HBMS) cells in response to IL-1beta and tumor necrosis factor-alpha. In the present study we investigated the regulation of IL-8 gene expression by IL-1beta, osteotropic hormones, and protein kinase inhibitors in primary cultures of HBMS cells. The treatment of HBMS cells with IL-1beta increased the steady-state levels of IL-8 mRNA in a dose- and time-dependent fashion and was detectable within 1 h, reached maximal by 4 h, and remained elevated at 24 h, whereas parathyroid hormone (10(-7) and 10(-8) M) had no effect on IL-8 mRNA. Both synthetic and natural glucocorticoids dexamethasone (10(-7)-10(-10) M) and hydrocortisone (10(-6)-10(-8) M) inhibited IL-1beta-stimulated IL-8 mRNA expression. The suppressive effect of dexamethasone on IL-1beta-induced IL-8 mRNA was not observed in the presence of cycloheximide (5 microg/ml), indicating that the dexamethasone-mediated repression of IL-8 gene expression also depends on new protein synthesis. Experiments with actinomycin D demonstrated that IL-8 mRNA is long-lived and that glucocorticoids down-regulate IL-8 gene expression mainly by decreasing the mRNA stability in normal HBMS cells. Furthermore, as determined by nuclear run-on analysis, IL-1beta increased the rate of transcription of IL-8 gene and dexamethasone did not affect the IL-1beta-induced transcription of IL-8. 1-(5-Isoquinolinesulfonyl)-2-methylpiperazine, HCl (50 microM) and staurosporine (1 microM), potent inhibitors of protein kinase C, and genistein (100 microM), a specific protein tyrosine kinase inhibitor blocked IL-1beta-induced IL-8 gene expression. Because curcumin (20 microM), an inhibitor of c-jun/AP-1 and protein kinases, also blocked IL-1beta-stimulated IL-8 gene expression implicating c-JUN/AP-1 and protein phosphorylation in the induction of IL-8 gene expression by IL-1beta, we conclude that the regulation of IL-8 mRNA by IL-1beta is mediated via protein kinase-dependent signal transduction pathways. Our accumulated results have demonstrated that glucocorticoid suppression of IL-1beta-induced IL-8 mRNA occurs at the levels of post-transcription (mRNA stability) and protein synthesis.
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PMID:Regulation of interleukin-8 gene expression by interleukin-1beta, osteotropic hormones, and protein kinase inhibitors in normal human bone marrow stromal cells. 866 79

Endothelial cells (EC) play a key role in the inflammatory response, both by the production of proinflammatory cytokines and by their interaction with leukocytes. Molecular genetic analysis has demonstrated that functional NF-kappa B sites are involved in the transcription of interleukin-6 (IL-6), IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) genes in response to inflammatory mediators. Thus, we have explored the effect of two inhibitors of the NF-kappa B activation, pyrrolidine dithiocarbamate (PDTC) and N-acetylcysteine (NAC), on the production of these cytokines by EC. Both PDTC and NAC inhibited, in a dose-dependent manner, the synthesis of IL-6, IL-8, and GM-CSF induced by tumor necrosis factor (TNF)-alpha or bacterial lipopolysaccharides (LPS) in human umbilical vein endothelial cells (HUVEC). PDTC appeared to prevent IL-6, IL-8, and GM-CSF gene transcription, as it blocked the induction of specific mRNA by TNF-alpha or LPS. The TNF-alpha mediated transcriptional activation of a chloramphenicol acetyltransferase (CAT) plasmid containing three copies of the -72 kappa B binding site from the IL-6 promoter was abrogated by PDTC. According to transfection experiments, electrophoretic mobility shift assays (EMSA) demonstrated that the antioxidant prevented the induction of NF-kappa B DNA-binding activity by TNF-alpha. Under the same conditions, PDTC by itself or in combination with TNF-alpha, enhanced the DNA-binding activity of AP-1, as well as c-fos and c-jun mRNA levels. Altogether, these results indicate that the antioxidant PDTC specifically inhibits the transcription of IL-6, IL-8, and GM-CSF genes through the inhibition of the NF-kappa B activation, while increasing the expression of AP-1. Our data make evident the antiinflammatory and immunoregulatory potential of the pharmacological inhibition of the NF-kappa B activation. In addition, PDTC and related molecules may be a useful tool to explore the expression of genes involved in the inflammatory response.
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PMID:Pyrrolidine dithiocarbamate inhibits the production of interleukin-6, interleukin-8, and granulocyte-macrophage colony-stimulating factor by human endothelial cells in response to inflammatory mediators: modulation of NF-kappa B and AP-1 transcription factors activity. 889 14

Glucocorticoids inhibit the expression and action of most cytokines. This is part of the in vivo feed-back system between inflammation-derived cytokines and CNS-adrenal produced corticosteroids with the probable physiological relevance to balance parts of the host defence and anti-inflammatory systems of the body. Glucocorticoids modulate cytokine expression by a combination of genomic mechanisms. The activated glucocorticoid-receptor complex can (i) bind to and inactivate key proinflammatory transcription factors (e.g. AP-1, NF kappa B). This takes place at the promotor responsive elements of these factors, but has also been reported without the presence of DNA; (ii) via glucocorticoid responsive elements (GRE), upregulate the expression of cytokine inhibitory proteins, e.g. I kappa B, which inactivates the transcription factor NF kappa B and thereby the secondary expression of a series of cytokines; (iii) reduce the half-life time and utility of cytokine mRNAs. In studies with triggered human blood mononuclear cells in culture, glucocorticoids strongly diminish the production of the 'initial phase' cytokines IL-1 beta and TNF-alpha and the 'immunomodulatory' cytokines IL-2, IL-3, IL-4, IL-5, IL-10, IL-12 and IFN-gamma, as well as of IL-6, IL-8 and the growth factor GM-CSF. While steroid treatment broadly attenuates cytokine production, it cannot modulate it selectively, e.g. just the TH0, the TH1 or the TH2 pathways. The production of the 'anti-inflammatory' IL-10 is also inhibited. The exceptions of steroid down-regulatory activity on cytokine expression seem to affect 'repair phase' cytokines like TGF-beta and PDGF. These are even reported to be upregulated, which may explain the rather weak steroid dampening action on healing and fibrotic processes. Some growth factors, e.g. G-CSF and M-CSF, are only weakly affected. In addition to diminishing the production of a cytokine, steroids can also often inhibit its subsequent actions. Because cytokines work in cascades, this means that steroid treatment can block expression of the subsequent cytokines. The blocked cytokine activity does not depend on a reduced cytokine receptor expression; in fact available in vitro investigations show that while the cytokine expression is blunted, its receptor is upregulated. The cellular studies presented here may represent the maximum potential of steroids to modulate cytokine expression in human mononuclear cells. It remains to be determined by clinical-experimental studies how effective cytokine modulation can be achieved in situ in inflamed bowel by systemic or by topical steroid therapy. Such studies may also answer whether a blocked cytokine production/action is the key or just a secondary mechanism behind the unique efficacy of steroids in active inflammatory bowel disease.
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PMID:Cytokine modulation by glucocorticoids: mechanisms and actions in cellular studies. 889 6

Interleukin-8 (IL-8), a potent neutrophil chemoattractant, can be expressed at high levels by many different cell types after immune stimulation. In contrast, expression of IL-8 in these same cells is virtually absent in the unstimulated state, demonstrating the tight regulation of the IL-8 gene. Although much is known about how this gene is transcriptionally activated after immune stimulation, little is known about the regulation of the IL-8 promoter in the absence of immune activation. In this study we examine how the IL-8 promoter is transcriptionally regulated in the uninduced state and how these mechanisms are altered in response to immune stimulation by IL-1beta. Electrophoretic mobility shift assay and transfection studies show that the IL-8 promoter is transcriptionally regulated by both positive and negative elements. Although the nuclear factor-kappaB (NFkappaB) element regulates only inducible activity of the IL-8 promoter in response to stimulation with IL-1beta, the AP-1 and CCAAT/Enhancer-binding Protein (C/EBP) elements influence both basal and inducible activities. In contrast to these three positive regulatory elements, the binding of the ubiquitously expressed POU-homeodomain transcription factor, Oct-1, strongly represses transcriptional activity of the IL-8 promoter by binding independently to an element overlapping that of C/EBP.
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PMID:Oct-1 and CCAAT/enhancer-binding protein (C/EBP) bind to overlapping elements within the interleukin-8 promoter. The role of Oct-1 as a transcriptional repressor. 899 51

Our previous studies have shown a different pattern of immediate early gene and growth factor gene expression between compensatory liver regeneration occurring after cell loss/death and direct hyperplasia induced by primary mitogens. In the present study, modifications in the activation of two transcription factors, NF-kappaB and AP-1; steady-state levels of tumor necrosis factor alpha (TNF-alpha) messenger RNA (mRNA); and induction of the inducible nitric oxide synthase (iNOS) were examined in rat liver during different types of cell proliferation. Compensatory regeneration was induced in male Wistar rats by partial hepatectomy of two thirds (PH) or a necrogenic dose of CCl4 (2 mL/kg), whereas direct hyperplasia was induced by a single administration of the primary mitogens lead nitrate (LN, 100 micromol/kg), cyproterone acetate (CPA, 60 mg/kg), or nafenopin (NAF, 200 mg/kg). Liver regeneration after treatment with CCl4 was associated with an increase in steady-state levels of TNF-alpha mRNA, activation of NF-kappaB and AP-1, and induction of iNOS. A strong and prolonged activation of NF-kappaB but not of AP-1 was observed in LN-induced hyperplasia. LN also induced an increase in hepatic levels of TNF-alpha and iNOS mRNA. On the other hand, direct hyperplasia induced by two other primary mitogens, NAF and CPA, occurred in the complete absence of modifications in the hepatic levels of TNF-alpha mRNA, activation of NF-kappaB and AP-1, or induction of iNOS, although the number of hepatocytes entering S phase 18 to 24 hours after NAF was similar to that seen after PH. These results add further support to the hypothesis that cell proliferation occurring in the absence of cell loss/death may be triggered by unknown signaling pathways different from those responsible for the transition of hepatocytes from G0 to G1 after PH or cell necrosis.
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PMID:Liver cell proliferation induced by nafenopin and cyproterone acetate is not associated with increases in activation of transcription factors NF-kappaB and AP-1 or with expression of tumor necrosis factor alpha. 904 3


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