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)

The transcription factor NF-kappaB can be activated in different forms, including transcriptional activating and repressing forms. Intestinal epithelial cells have been found to modulate the relative levels of the p65-p50 and p50-p50 NF-kappaB complexes in a number of instances, and here we show that this ratio was altered in response to dietary fiber (wheat bran) and carcinogen exposure (azoxymethane). The influence of these complexes on gene regulation was examined in more detail in cell culture models. The colon-derived HT-29 cell line likewise activated both p65-p50 and p50-p50 NF-kappaB complexes: TNF-alpha triggered a strong, sustained p65-p50 activation with lower relative levels of p50-p50, whereas IL-1beta transiently activated p65-p50 with higher relative levels of p50-p50. Transfection experiments with an NF-kappaB reporter plasmid indicated that p50 was a repressor in HT-29 cells. Increased expression of the p50-p50 dimer by an adenovirus showed that the p50-p50 dimer suppressed IL-1beta activation of endogenous genes more than 5-fold (TNF-alpha, Cox-2 and IL-8), whereas gene activation by TNF-alpha was not significantly affected. DNA binding analyses showed a number of strong p50-p50 binding sites on these promoters. The selective p50-p50 suppression of IL-1beta gene activation corresponded to the transient nature of p65-p50 activation induced by IL-1beta (in both HT-29 and Caco-2 cells). Our findings demonstrate a novel gene regulatory mechanism for the NF-kappaB p50-p50 complex: a signal-specific transcriptional repression that appears to selectively inhibit stimuli that transiently activate p65-p50 complexes.
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PMID:The p50-p50 NF-kappaB complex as a stimulus-specific repressor of gene activation. 1554 47

Viral latency is a long-term pathogenic condition in patients infected with HIV-1. Low but sustained virus replication in chronically infected cells can be activated by stimulation with proinflammatory cytokines such as TNF-alpha, IL-1 beta, or other host factors. However, the precise mechanism by which cellular activation induces latently infected cells to produce virions has remained unclear. In the present report, we present evidence that activation of HIV-1 replication in latently infected U1 or ACH2 cells by human macrophages is mediated by a rapid nuclear localization of NF-kappaB p50/p65 dimer with concomitant increased expression of proinflammatory cytokines. Multiplexed RT-PCR amplification of mRNA isolated from cocultures of macrophages and U1 and ACH2 cells showed significant induction of IL-1beta, IL-6, IL-8, TNF-alpha, and TGF-beta expression within 3 h of coincubation. Fixation of macrophages, U-1, or ACH2 cells with paraformaldehyde before coculture completely abrogated the induction of NF-kappaB subunits and HIV-1 replication, suggesting that cooperative interaction between the two cell types is an essential process for cellular activation. Pretreatment of macrophage-U1 or macrophage-ACH2 cocultures with neutralizing anti-TNF-alpha Ab down-regulated the replication of HIV-1. In addition, pretreatment of macrophage-U1 or macrophage-ACH2 cocultures with the NF-kappaB inhibitor (E)3-[(4-methylphenyl)sulfonyl]-2-propenenitrile (BAY 11-7082) prevented the induction of cytokine expression, indicating a pivotal role of NF-kappaB-mediated signaling in the reactivation of HIV-1 in latently infected cells by macrophages. These results provide a mechanism by which macrophages induce HIV-1 replication in latently infected cells.
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PMID:Mechanisms for macrophage-mediated HIV-1 induction. 1555 66

We previously designed and synthesized the new nuclear factor kappaB (NF-kappaB) inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) derived from the structure of the antibiotic epoxyquinomicin C. We looked into the effect of DHMEQ on cellular phenotypes and tumor growth in mice injected with human breast carcinoma cell line MDA-MB-231 or MCF-7. In estrogen-independent breast adenocarcinoma cell line MDA-MB-231, NF-kappaB is constitutively activated. The addition of DHMEQ (10 microg/mL) completely inhibited the activated NF-kappaB for at least 8 hours. On the other hand, NF-kappaB is not activated in estrogen-dependent MCF-7 cells. In this cell line, DHMEQ completely inhibited the tumor necrosis factor-alpha-induced activation of NF-kappaB. DHMEQ did not inhibit the degradation of IkappaB but inhibited the nuclear translocation of NF-kappaB by both p65/p50 and RelB/p52 pathways. MDA-MB-231 cells secrete interleukin (IL)-6 and IL-8 without stimulation, and DHMEQ decreased the secretion levels of both cytokines. When MDA-MB-231 or MCF-7 cells were stimulated by tumor necrosis factor-alpha, the inhibitory effects of DHMEQ were still maintained. I.p. administration of DHMEQ (thrice a week) significantly inhibited the tumor growth of MDA-MB-231 (12 mg/kg) or MCF-7 (4 mg/kg) in severe combined immunodeficiency mice. No toxicity was observed during the experiment, including the loss of body weight. An immunohistological study on resected MCF-7 tumors showed that DHMEQ inhibited angiogenesis and promoted apoptosis. Furthermore, in Adriamycin-resistant MCF-7 cells highly expressing multidrug resistance gene-1, DHMEQ also exhibited the above capability, including down-regulation of IL-8. Thus, DHMEQ might be a potent drug for the treatment of various breast carcinomas by inhibiting the NF-kappaB activity.
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PMID:Targeting of nuclear factor kappaB Pathways by dehydroxymethylepoxyquinomicin, a novel inhibitor of breast carcinomas: antitumor and antiangiogenic potential in vivo. 1570

Salmonella-epithelial cell interactions are known to activate the proinflammatory NF-kappaB signaling pathway and have recently been found to also influence the beta-catenin signaling pathway, an important regulator of epithelial cell proliferation and differentiation. Here, using polarized epithelial cell models, we demonstrate that these same bacteria-mediated effects also direct the molecular crosstalk between the NF-kappaB and beta-catenin signaling pathways. Convergence of these two pathways is a result of the direct interaction between the NF-kappaB p50 subunit and beta-catenin. We show that PhoP(c), the avirulent derivative of a wild-type Salmonella strain, attenuates NF-kappaB activity by stabilizing the association of beta-catenin with NF-kappaB. In cell lines expressing constitutively active beta-catenin, IkappaBalpha protein was indirectly stabilized and NF-kappaB activity was repressed after wild-type Salmonella colonization. Accordingly, constitutively active beta-catenin was found to inhibit the secretion of IL-8. Thus our findings strongly suggest that the crosstalk between the beta-catenin and NF-kappaB signaling pathways is an important regulator of intestinal inflammation.
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PMID:Crosstalk between NF-kappaB and beta-catenin pathways in bacterial-colonized intestinal epithelial cells. 1579 Jul 58

We investigated the transcriptional regulation of secretion of pro- and anti-inflammatory mediators by human colonic circular smooth muscle cells (HCCSMC) in response to tumor necrosis factor (TNF)-alpha. Gene chip array analysis indicated that HCCSMC express a specific panel of 11 cytokines, chemokines, and cell adhesion molecules in a time-dependent manner in response to TNF-alpha. The chip array data were supported by quantitative analysis of mRNA and protein expressions of interleukin (IL)-6, IL-8, intercellular adhesion molecule (ICAM)-1 and IL-11. The proinflammatory mediators were expressed early, whereas the anti-inflammatory cytokine IL-11 was expressed late after TNF-alpha treatment. The expression of ICAM-1 on HCCSMC increased lymphocyte adhesion to these cells, which was blocked by pretreatment with antibody to ICAM-1. TNF-alpha acted on both R(1) and R(2) receptors to induce the expression of ICAM-1. Pretreatment of HCCSMC with antisense oligonucleotides to p65 nuclear factor-kappaB (NF-kappaB) blocked the expression of ICAM-1, whereas pretreatment with antisense oligonucleotides to p50 NF-kappaB had little effect. The overexpression of p65 NF-kappaB enhanced the constitutive expression of ICAM-1, and TNF-alpha treatment had no further effect. The delayed expression of endogenous IL-11 limited the expression of ICAM-1, and pretreatment of HCCSMC with antisense oligonucleotides to IL-11 enhanced it. We conclude that TNF-alpha induces gene expression in HCCSMC for programmed synthesis and release of pro- and anti-inflammatory mediators.
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PMID:Transcriptional regulation of inflammatory mediators secreted by human colonic circular smooth muscle cells. 1579 Jul 59

To investigate the determinants of promoter-specific gene regulation by the glucocorticoid receptor (GR), we compared the composition and function of regulatory complexes at two NFkappaB-responsive genes that are differentially regulated by GR. Transcription of the IL-8 and IkappaBalpha genes is stimulated by TNFalpha in A549 cells, but GR selectively represses IL-8 mRNA synthesis by inhibiting Ser2 phosphorylation of the RNA polymerase II (pol II) C-terminal domain (CTD). The proximal kappaB elements at these genes differ in sequence by a single base pair, and both recruited RelA and p50. Surprisingly, GR was recruited to both of these elements, despite the fact that GR failed to repress the IkappaBalpha promoter. Rather, the regulatory complexes formed at IL-8 and IkappaBalpha were distinguished by differential recruitment of the Ser2 CTD kinase, P-TEFb. Disruption of P-TEFb function by the Cdk-inhibitor, DRB, or by small interfering RNA selectively blocked TNFalpha stimulation of IL-8 mRNA production. GR competed with P-TEFb recruitment to the IL-8 promoter. Strikingly, IL-8 mRNA synthesis was repressed by GR at a post-initiation step, demonstrating that promoter proximal regulatory sequences assemble complexes that impact early and late stages of mRNA synthesis. Thus, GR accomplishes selective repression by targeting promoter-specific components of NFkappaB regulatory complexes.
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PMID:The glucocorticoid receptor blocks P-TEFb recruitment by NFkappaB to effect promoter-specific transcriptional repression. 1587 58

Escherichia coli is associated with inflammation in the brain. To investigate whether astrocytes are involved in E. coil-induced inflammation, we assessed the levels of expression of proinflammatory mediators produced by E. coli-infected astrocytes. E. coli infection in primary human astrocytes and cell lines increased expression of the CXC chemokine IL-8/GRO-alpha, the CC chemokine MCP-1, TNF-alpha, and iNOS. E. coli infection activated p65/p50 heterodimeric NF-kappaB and concurrently decreased the signals of IkappaBalpha. Blocking the NF-kappaB signals by IkappaBalpha-superrepressor-containing retrovirus or antisense p50 oligonucleotide transfection resulted in down-regulation of expression of the proinflammatory mediators. Furthermore, superrepressors of IkappaBalpha, IkappaB kinase (IKK) or NF-kappaB inducing kinase (NIK) inhibited the up-regulated expression of the downstream target genes of NF-kappaB such as IL-8 and MCP-1, and superrepressors of TNF receptor-associated factor (TRAF)2 and TRAF5 also inhibited expression of the E. coli-induced target genes of NF-kappaB. These results indicate that proinflammatory mediators such as the CXC chemokine IL-8/GRO-alpha, the CC chemokine MCP-1, TNF-alpha, and iNOS can be expressed in E. coli-infected astrocytes via an NF-kappaB pathway, suggesting that these mediators may contribute to inflammation in the brain, including infiltration of inflammatory cells.
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PMID:Induction of proinflammatory mediators requires activation of the TRAF, NIK, IKK and NF-kappaB signal transduction pathway in astrocytes infected with Escherichia coli. 1593 6

Neurocysticercosis, caused by infection with larval Taenia solium, is a major cause of epilepsy worldwide. Larval degeneration, which is symptomatic, results in inflammatory cell influx. Astrocytes, the most abundant cell type and major cytokine-producing cell within the CNS, may be important in orchestrating inflammatory responses after larval degeneration. We investigated the effects of direct stimulation and of conditioned medium from T. solium larval Ag (TsAg)-stimulated monocytes (CoMTsAg) on neutrophil and astrocyte chemokine release. CoMTsAg, but not control conditioned medium, stimulated astrocyte CCL2/MCP-1 (161.5 +/- 16 ng/ml), CXCL8/IL-8 (416 +/- 6.2 ng/ml), and CXCL10/IFN-gamma-inducible protein (9.07 +/- 0.6 ng/ml) secretion after 24 h, whereas direct astrocyte or neutrophil stimulation with TsAg had no effect. There was rapid accumulation of CCL2 and CXCL8 mRNA within 1 h, with somewhat delayed expression of CXCL10 mRNA initially detected 8 h poststimulation. Neutralizing anti-TNF-alpha inhibited CoMTsAg-induced CCL2 mRNA accumulation by up to 99%, causing total abolition of CXCL10 and up to 77% reduction in CXCL8 mRNA. CoMTsAg induced maximal nuclear binding of NF-kappaB p65 and p50 by 1 h, with IkappaBalpha and IkappaBbeta decay within 15 min. In addition, CoMTsAg induced transient nuclear binding of AP-1, which peaked 4 h poststimulation. In NF-kappaB blocking experiments using pyrrolidine dithiocarbamate, CoMTsAg-induced CCL2 secretion was reduced by up to 80% (p = 0.0006), whereas CXCL8 was inhibited by up to 75% (p = 0.0003). In summary, the data show that astrocytes are an important source of chemokines following larval Ag stimulation. Such chemokine secretion is NF-kappaB dependent, likely to involve AP-1, and is regulated in a paracrine loop by monocyte-derived TNF-alpha.
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PMID:Monocyte-astrocyte networks and the regulation of chemokine secretion in neurocysticercosis. 1611 19

Lung epithelial cells are the primary cellular targets for respiratory virus pathogens such as influenza and parainfluenza viruses. Here, we have analyzed influenza A, influenza B and Sendai virus-induced chemokine response in human A549 lung epithelial cells. Influenza virus infection resulted in low CCL2/MCP-1, CCL5/RANTES, CXCL8/IL-8 and CXCL10/IP-10 production at late times of infection. However, when cells were pretreated with TNF-alpha or IFN-alpha, influenza-A-virus-induced chemokine production was greatly enhanced. Cytokine pretreatment resulted in enhanced expression of RIG-I, IKKepsilon, interferon regulatory factor (IRF)1, IRF7 and p50 proteins. Most importantly, influenza-A-virus-induced DNA binding of IRF1, IRF3, IRF7 and NF-kappaB onto CXCL10 ISRE and NF-kappaB elements, respectively, was markedly enhanced in cytokine-pretreated cells. Our results suggest that IFN-alpha and TNF-alpha have a significant role in priming epithelial cells for higher cytokine and chemokine production in influenza A virus infection.
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PMID:TNF-alpha and IFN-alpha enhance influenza-A-virus-induced chemokine gene expression in human A549 lung epithelial cells. 1625 3

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


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