Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thiopental is one of the intravenous anesthetics used widely. Several reports have demonstrated that thiopental inhibits the immune responses. We investigated whether or not thiopental inhibits the production of tumor necrosis factor-alpha (TNF-alpha) induced by lipopolysaccharide (LPS) in human glioma cells (A-172). Moreover, we determined whether or not thiopental modulates activation of the transcription factor NF-kappaB, a factor that regulates expression of the genes that code for proinflammatory cytokines in A-172 cells and in experimental murine brain inflammation. Thiopental inhibited TNF-alpha production induced by LPS in A-172 cells. Electrophoretic mobility shift assays demonstrated that thiopental inhibited NF-kappaB activation induced by LPS in A-172 cells. In experimental murine brain inflammation induced by intracerebroventricular injection of LPS, intraperitoneal injection of thiopental inhibited NF-kappaB activation. Western blot analysis indicated that this inhibition was linked to preservation of IkappaBalpha protein expression in A-172 cells. The chloramphenicol acetyltransferase assay revealed that NF-kappaB-dependent reporter gene expression was suppressed in A-172 cells exposed to thiopental. These findings are consistent with the idea that thiopental exerts antiinflammatory effects in cultured cells and experimental murine brain inflammation, through suppression of TNF-alpha production via inhibition of NF-kappaB activation.
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PMID:Thiopental inhibits NF-kappaB activation in human glioma cells and experimental brain inflammation. 1148 44

NF-kappaB/Rel transcription factors have been implicated in the differentiation of monocytes to either dendritic cells (DCs) or macrophages, as well as in the maturation of DCs from antigen-processing to antigen-presenting cells. Recent studies of the expression pattern of Rel proteins and their inhibitors (IkappaBs) suggest that their regulation during this differentiation process is transcriptional. To investigate differential gene expression between macrophages and DCs, we used commercially available gene microarrays (GEArray KIT), which included four of the NF-kappaB/Rel family genes (p50/p105, p52/p100, RelB, and c-rel) and 32 additional genes either in the NF-kappaB signal transduction pathway or under transcriptional control of NF-kappaB/Rel factors. To generate macrophages and DCs, human adherent peripheral blood monocytes were cultured with M-CSF or GM-CSF + IL-4 respectively for up to 8 days. DCs (and in some experiments, macrophages) were treated with lipopolysaccharide (LPS) for the last 48 h of culture to induce maturation. Cells were harvested after 7 days, cDNA was prepared and radiolabeled with alpha-(32)P-dCTP, then hybridized to gene arrays containing specific gene probes. beta-actin and GAPDH or PUC18 oligonucleotides served as positive or negative controls, respectively. The expression of all four NF-kappaB/Rel family genes examined was significantly upregulated in maturing DCs compared to macrophages. The strongest difference was observed for c-rel. RT-PCR determinations of c-rel, RelB, and p105 mRNAs confirmed these observations. Among the 32 NF-kappaB/Rel pathway genes, 14 were upregulated in mature DCs compared to macrophages. These genes were IkappaBalpha, IKK-beta, NIK, ICAM-1, P-selectin, E-selectin, TNF-alpha, TNFR2, TNFAIP3, IL-1alpha, IL-1R1, IL-1R2, IRAK, and TANK. By contrast, only mcp-1 (monocyte chemotactic protein 1) was upregulated in macrophages compared to DCs. NF-kappaB pathway genes upregulated in DCs compared to macrophages were constitutively expressed in monocytes then selectively downregulated during macrophage but not DC differentiation. LPS did not induce expression of most of these genes in macrophages but LPS did induce upregulation of IL-8 in mature macrophages. We conclude that NF-kappaB/Rel family genes, especially c-rel, are selectively expressed during differentiation of monocytes towards DCs. Moreover, this differential expression is associated both with activation of different NF-kappaB signal transduction pathways in DCs and macrophages and with expression of a unique subset of genes in DCs that are transcriptionally targeted by NF-kappaB/Rel factors. The results illustrate the ability of the NF-kappaB pathway to respond to differentiation stimuli by activating in a cell-specific manner unique signalling pathways and subsets of NF-kappaB target genes.
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PMID:Expression of different NF-kappaB pathway genes in dendritic cells (DCs) or macrophages assessed by gene expression profiling. 1157 45

The proto-oncogene c-myb is essential for a controlled balance between cell growth and differentiation. Aberrant c-Myb activity has been reported for numerous human cancers, and enforced c-Myb transcription can transform cells of lymphoid origin by stimulating cellular proliferation and inhibiting apoptotic pathways. Here we demonstrate that activation of the NF-kappaB pathway by the HTLV-1 Tax protein leads to transcriptional inactivation of c-Myb. This conclusion was supported by the fact that Tax mutants unable to stimulate the NF-kappaB pathway could not inhibit c-Myb transactivating functions. In addition, inhibition of Tax-mediated NF-kappaB activation by coexpression of IkappaBalpha restored c-Myb transcription, and Tax was unable to block c-Myb transcription in a NEMO knockout cell line. Importantly, physiological stimuli, such as signaling with the cellular cytokines tumor necrosis factor alpha, interleukin 1 beta (IL-1beta), and lipopolysaccharide, also inhibited c-Myb transcription. These results uncover a new link between extracellular signaling and c-Myb-dependent transcription. The mechanism underlying NF-kappaB-mediated repression was identified as sequestration of the coactivators CBP/p300 by RelA. Interestingly, an amino-terminal deletion form of p300 lacking the C/H1 and KIX domains and unable to bind RelA retained the ability to stimulate c-Myb transcription and prevented NF-kappaB-mediated repression.
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PMID:Human T-cell lymphotropic virus type 1 Tax represses c-Myb-dependent transcription through activation of the NF-kappaB pathway and modulation of coactivator usage. 1158 20

Unmethylated CpG motifs in bacterial DNA (CpG DNA) activate host innate immune responses synergistically with some other microbial products, such as endotoxins, and may contribute to disease pathogenesis through excessive production of proinflammatory cytokines. Because monocyte-derived tumor necrosis factor (TNF)-alpha is an important mediator of disease, we investigated whether CpG DNA and lipopolysaccharide (LPS) synergize for inducing TNF-alpha biosynthesis. CpG DNA and LPS synergistically induce TNF-alpha production in RAW264.7 cells and J774 cells through activation of NF-kappaB. Furthermore, transient transfection with a super-repressive mutant of IkappaBalpha (IkappaBalpha-AA) demonstrated that NF-kappaB plays a critical role in CpG DNA-mediated TNF-alpha expression. Like NF-kappaB activation, CpG DNA-induced activation of mitogen-activated protein kinases (MAPK) regulates TNF-alpha production. Both extracellular receptor kinase (ERK) and p38 can regulate TNF-alpha gene transcription induced by CpG DNA. Although CpG DNA at the higher concentration slightly enhanced LPS-mediated phosphorylation of ERK, it did not alter the LPS-mediated activation of c-Jun N-terminal kinase and p38. In addition, CpG DNA showed little or no enhancement of LPS-mediated AP-1 activation. These results suggest that CpG DNA- and LPS-mediated signals converge at or above the level of NF-kappaB and ERK, and that there are distinct, as well as common, signaling pathways which are utilized by both CpG DNA and LPS for activating various transcription factors and MAPK.
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PMID:Lipopolysaccharide and CpG DNA synergize for tumor necrosis factor-alpha production through activation of NF-kappaB. 1167 71

The recent characterization of human homologs of Toll may be the missing link for the transduction events leading to nuclear factor-kappaB (NF-kappaB) activity and proinflammatory gene transcription during innate immune response. Mammalian cells may express as many as 10 distinct Toll-like receptors (TLRs), although TLR2 is a key receptor for recognizing cell wall components of Gram-positive bacteria. The present study investigated the effects of circulating bacterial cell wall components on the expression of the gene-encoding TLR2 across the mouse brain. Surprisingly, while Gram-negative components caused a robust increase in TLR2 transcription within the cerebral tissue, peptidoglycan (PGN) and lipoteichoic acid (LTA), either alone or combined, failed to modulate the receptor transcript. Indeed, the mRNA levels for TLR2 in the choroid plexus and few other regions of the brain remained similar between vehicle-, LTA-, PGN-, and LTA/PGN-administered mice at all the times evaluated (i.e. 30 min to 24 h post-intraperitoneal injection). This contrasts with the profound de novo expression of TLR2 following a single systemic injection of the lipopolysaccharide (LPS). The signal was first detected in regions devoid of blood-brain barrier and few blood vessels and microcapillaries. A second wave of TLR2 expression was also detected from these structures to their surrounding parenchymal cells that stained for a microglial marker iba1. The rapid induction of IkappaBalpha (index of NF-kappaB activity) and up-regulation of the adaptor protein MyD88 suggest that LPS-induced TLR2 transcription may be dependent on the NF-kappaB pathway. These data provide the evidence that TLR2 is not only present in the brain, but its encoding gene is regulated by cell wall components derived from Gram-negative, not Gram-positive, bacteria. The robust wave of TLR2-expressing microglial cells may have a determinant impact on the innate immune response that occurs in the brain during systemic infection by Gram-negative, not Gram-positive, bacteria.
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PMID:Circulating cell wall components derived from gram-negative, not gram-positive, bacteria cause a profound induction of the gene-encoding Toll-like receptor 2 in the CNS. 1170 68

1. In this study we examined the signalling events that regulate lipopolysaccharide (LPS)-stimulated induction of interferon regulatory factor (IRF)-1 in human umbilical vein endothelial cells (HUVECs). 2. LPS stimulated a time- and concentration-dependent increase in IRF-1 protein expression, an effect that was mimicked by the cytokine, tumour necrosis factor (TNF)-alpha. 3. LPS stimulated a rapid increase in nuclear factor kappa B (NFkappaB) DNA-binding activity. Pre-incubation with the NFkappaB pathway inhibitors, N-alpha-tosyl-L-lysine chloromethyl ketone (TLCK) or pyrrolidine dithiocarbamate (PDTC), or infection with adenovirus encoding IkappaBalpha, blocked both IRF-1 induction and NFkappaB DNA-binding activity. 4. LPS and TNFalpha also stimulated a rapid activation of gamma interferon activation site/gamma interferon activation factor (GAS/GAF) DNA-binding in HUVECs. Preincubation with the Janus kinase (JAK)-2 inhibitor, AG490 blocked LPS-stimulated IRF-1 induction but did not affect GAS/GAF DNA-binding. 5. Preincubation with TLCK, PDTC or infection with IkappaBalpha adenovirus abolished LPS-stimulated GAS/GAF DNA-binding. 6. Incubation of nuclear extracts with antibodies to RelA/p50 supershifted GAS/GAF DNA-binding demonstrating the involvement of NFkappaB isoforms in the formation of the GAS/GAF complex. 7. These studies show that NFkappaB plays an important role in the regulation of IRF-1 induction in HUVECs. This is in part due to the interaction of NFkappaB isoforms with the GAS/GAF complex either directly or via an intermediate protein.
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PMID:Nuclear factor kappa B is involved in lipopolysaccharide-stimulated induction of interferon regulatory factor-1 and GAS/GAF DNA-binding in human umbilical vein endothelial cells. 1173 38

Endotoxin (lipopolysaccharide, LPS) is a component of the outer membrane of Gram-negative bacteria and promotes the activation of macrophages and microglia. Although these cells are highly LPS-responsive, they serve unique tissue-specific functions and exhibit different LPS sensitivities. Accordingly, it was of interest to evaluate whether these biological differences reside in variations within LPS signaling pathways between these two cell types. Because the mitogen-activated protein kinases ERK-1 and ERK-2 have been implicated in the control of many immune responses, we tested the concept that they are a key indicator for differences in cellular LPS sensitivity. We observed that murine RAW 264.7 macrophages and murine BV-2 microglial cells both respond to LPS by exhibiting increased IkappaBalpha degradation, enhanced NF-kappaB DNA binding activity, and elevated nitric oxide and interleukin-1beta production. Although LPS potently stimulates ERK activation in RAW 264.7 macrophages, it does not activate ERK-1/-2 in BV-2 microglia. Moreover, antagonism of the MEK/ERK pathway potentiates LPS-stimulated nitric oxide production, suggesting that LPS-stimulated ERK activation can exert inhibitory effects in macrophage-like cells. These data support the idea that ERK activation is not a required function of LPS-mediated signaling events and illustrate that alternative/additional pathways for LPS action exist in these cell types.
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PMID:A differential role for the mitogen-activated protein kinases in lipopolysaccharide signaling: the MEK/ERK pathway is not essential for nitric oxide and interleukin 1beta production. 1178 32

Although tumor necrosis factor (TNF)-alpha is implicated in numerous cardiac pathologies, the intracellular events leading to its production by heart cells are largely unknown. The goal of the present study was to identify the role of the transcription factor nuclear factor (NF)-kappaB in this process. Among the many inducers of TNF-alpha expression in myeloid cells, only lipopolysaccharide (LPS) led to its induction in cultured neonatal myocytes. LPS also activated the NF-kappaB pathway, as evidenced by the degradation of the inhibitory protein IkappaB and the appearance of NF-kappaB-binding complexes in nuclear extracts. Furthermore, inhibitors of NF-kappaB activation, such as lactacystin, MG132, and pyrrolidine dithiocarbamate, were found to completely block the production of TNF-alpha in response to LPS stimulation, indicating a requirement of NF-kappaB for TNF-alpha expression. However, interleukin-1beta and phorbol 12-myristate 13-acetate also activated NF-kappaB but did not evoke TNF-alpha expression, revealing that this factor is not sufficient for cytokine production. Detailed examination of the NF-kappaB cascade revealed that cardiac cells displayed a unique pattern of IkappaB degradation in response to LPS, with IkappaBbeta but not IkappaBalpha being degraded upon stimulation. Additionally, two specific p65-containing DNA-binding complexes were observed in the nuclear extracts of neonatal cardiomyocytes: an inducible complex that is necessary for TNF-alpha expression and a constitutive species. Taken together, these results reveal that NF-kappaB is not only involved in cytokine production but also may be linked to other pathways that subserve a constitutive, protective mechanism for the heart cell.
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PMID:Endotoxin stress-response in cardiomyocytes: NF-kappaB activation and tumor necrosis factor-alpha expression. 1183 81

Several recent reports have suggested that airway inflammation may precede infection and relate to an endogenous dysregulation of pro-inflammatory cytokines in cystic fibrosis (CF) airways. Evidence suggests that activation of the nuclear factor kappa B (NFkappaB), which regulates the inflammatory gene transcription, depends on the degradation of the inhibitory factor IkappaBalpha. We show that, in in situ human DeltaF508 CF bronchial tissues, inhibitor factor IkappaBalpha is not present in gland cells, although endogenous levels of chemokine IL-8 are high. These data are confirmed by studying cultured CF human bronchial gland cells, in which a lack of cytosolic IkappaBalpha and high levels of activated NFkappaB, concomitant with IL-8 overproduction (a 13-fold increase) are found when compared to non-CF bronchial gland cells. Interestingly, treatment of CF gland cells with the isoflavone genistein, a well known CFTR mutant Cl(-) channel stimulator, results in a significant decrease ( P < 0.001) in IL-8 production down to levels released by non-CF gland cells. The addition of genistein also reverses the effects of lipopolysaccharide (LPS) Pseudomonas-aeruginosa-induced nuclear translocation of NFkappaB by increasing IkappaBalpha protein level (65%) in CF gland cells. Our data indicate that the induction of IkappaBalpha protein in CF airway glandular epithelial cells may be a novel mechanism by which IL-8-mediated lung inflammatory events are markedly reduced in CF patients, at least at the airway glandular level.
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PMID:Relationship between IkappaBalpha deficiency, NFkappaB activity and interleukin-8 production in CF human airway epithelial cells. 1184 1

Human alveolar macrophages (HAM) express FcalphaR receptors for immunoglobulin (Ig)A which could link humoral and cellular branches of lung immunity. Here, we investigate the effects of polymeric (p-IgA) and secretory (S-IgA) IgA interaction with Fc(alpha)R on lipopolysaccharide (LPS)- and phorbol myristate acetate (PMA)-activated respiratory burst and TNF-alpha release by HAM. Activation of HAM with LPS and PMA increases the respiratory burst and TNF-alpha release through activation of the extracellular signal-related protein kinases 1 and 2 (ERK1/2) pathway, because these effects are inhibited by treatment of HAM with PD98059, a selective inhibitor of mitogen-activated protein (MAP)/ERK kinases (MEK) pathway. S-IgA and p-IgA downregulate the LPS-increased respiratory burst in HAM through an inhibition of ERK1/2 activity. In contrast, p- and S-IgA induce an increase in the respiratory burst of PMA-treated HAM. This effect is associated with an upregulation by IgA of the PMA-induced phosphorylation of ERK1/2 and is also inhibited by PD98059. Moreover, p-IgA and S-IgA enhance TNF-alpha release by HAM through an alternative pathway distinct from ERK1/2. Because LPS is known to activate nuclear factor-kappaB (NF-kappaB) in HAM, we evaluate the effect of IgA on NF-kappaB. Treatment of HAM with LPS, p- and S-IgA, but not PMA, induces NF-kappaB activation through IkappaBalpha phosphorylation and subsequent proteolysis. Antioxidants, namely N-acetylcysteine (NAC) and glutathione (GSH), have no effects on IgA-mediated NF-kappaB nuclear translocation and only a minor and late effect on that of LPS, suggesting that reactive oxygen intermediates (ROI) play a minor role in HAM activation through NF-kappaB. TNF-alpha release by LPS-activated HAM is sensitive to NF-kappaB inhibition and only partly to oxidant scavenging. In contrast, TNF-alpha release by IgA-treated HAM is not dependent on oxidants and only partly dependent on NF-kappaB. Our results show a differential HAM regulation by IgA through both dependent and independent modulation of ERK pathway. In addition, IgA activates NF-kappaB and this effect was independent on oxidants. These data may help to understand the role of IgA in both lung protection and inflammation.
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PMID:Effect of IgA on respiratory burst and cytokine release by human alveolar macrophages: role of ERK1/2 mitogen-activated protein kinases and NF-kappaB. 1186 40


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