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)

Cyclosporine A is an immunosuppressive agent that is used clinically in the prevention of transplant rejection and development of graft-versus-host disease. Recently, cyclosporine A has been shown to possess anti-inflammatory properties and is capable of inhibiting lipopolysaccharide-induced NF-kappaB activation. Ubiquitin-mediated proteasomal proteolysis plays a critical role in signal-induced NF-kappaB activation since it regulates both IkappaB degradation and p105 processing, it is also involved in the production of peptides for the assembly of MHC class I molecules. We report here that cylcosporine A acts as an uncompetitive inhibitor of the chymotrypsin-like activity of the 20S proteasome in vitro and that it suppresses lipopolysaccharide-induced IkappaB degradation and p105 processing in vivo demonstrating that inhibition of proteasome proteolysis is the mechanism by which cyclosporine A prevents NF-kappaB activation. A structurally unrelated immunosuppressant, rapamycin, did not inhibit the 20S proteasome in vitro.
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PMID:Cyclosporine A is an uncompetitive inhibitor of proteasome activity and prevents NF-kappaB activation. 928 Mar 12

p105 (NFKB1) acts in a dual way as a cytoplasmic IkappaB molecule and as the source of the NF-kappaB p50 subunit upon processing. p105 can form various heterodimers with other NF-kappaB subunits, including its own processing product, p50, and these complexes are signal responsive. Signaling through the IkappaB kinase (IKK) complex invokes p105 degradation and p50 homodimer formation, involving p105 phosphorylation at a C-terminal destruction box. We show here that IKKbeta phosphorylation of p105 is direct and does not require kinases downstream of IKK. p105 contains an IKK docking site located in a death domain, which is separate from the substrate site. The substrate residues were identified as serines 923 and 927, the latter of which was previously assumed to be a threonine. S927 is part of a conserved DSGPsi motif and is functionally most critical. The region containing both serines is homologous to the N-terminal destruction box of IkappaBalpha, -beta, and -epsilon. Upon phosphorylation by IKK, p105 attracts the SCF E3 ubiquitin ligase substrate recognition molecules betaTrCP1 and betaTrCP2, resulting in polyubiquitination and complete degradation by the proteasome. However, processing of p105 is independent of IKK signaling. In line with this and as a physiologically relevant model, lipopolysaccharide (LPS) induced degradation of endogenous p105 and p50 homodimer formation, but not processing in pre-B cells. In mutant pre-B cells lacking IKKgamma, processing was unaffected, but LPS-induced p105 degradation was abolished. Thus, a functional endogenous IKK complex is required for signal-induced p105 degradation but not for processing.
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PMID:Shared pathways of IkappaB kinase-induced SCF(betaTrCP)-mediated ubiquitination and degradation for the NF-kappaB precursor p105 and IkappaBalpha. 1115 90

It was previously shown that plasmin activates human peripheral monocytes in terms of lipid mediator release and chemotactic migration. Here it is demonstrated that plasmin induces proinflammatory cytokine release and tissue factor (TF) expression by monocytes. Plasmin 0.043 to 1.43 CTA U/mL, but not active site-blocked plasmin, triggered concentration-dependent expression of mRNA for interleukin-1alpha (IL-1alpha), IL-1beta, tumor necrosis factor-alpha (TNF-alpha), and TF with maximum responses after 4 hours. Plasmin-mediated mRNA expression was inhibited in a concentration-dependent manner by the lysine analogue trans-4-(aminomethyl)cyclohexane-1-carboxylic acid (t-AMCA). Increases in mRNA levels were followed by concentration- and time-dependent release of IL-1alpha, IL-1beta and TNF-alpha and by TF expression on monocyte surfaces. Neither cytokines nor TF could be detected when monocytes were preincubated with actinomycin D or cycloheximide. Electrophoretic mobility shift assays indicated plasmin-induced activation of NF-kappaB; DNA-binding complexes were composed of p50, p65, and c-Rel, as shown by supershift experiments. Nuclear translocation of NF-kappaB/Rel proteins coincided with IkappaBalpha degradation. At variance with endotoxic lipopolysaccharide, plasmin elicited the rapid degradation of another cytoplasmic NF-kappaB inhibitor, p105. Proteolysis of NF-kappaB inhibitors was apparently due to transient activation of IkappaB kinase (IKK) beta that reached maximum activity at 1 hour after plasmin stimulation. In addition, AP-1 binding was increased in plasmin-treated monocytes, with most complexes composed of JunD, c-Fos, and FosB. These findings further substantiate the role of plasmin as a proinflammatory activator of human monocytes and reveal an important new link between the plasminogen-plasmin system and inflammation. (Blood. 2001;97:3941-3950)
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PMID:Plasmin-induced expression of cytokines and tissue factor in human monocytes involves AP-1 and IKKbeta-mediated NF-kappaB activation. 1138 38

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

Inflammatory bladder disorders such as interstitial cystitis (IC) deserve attention since a major problem of the disease is diagnosis. IC affects millions of women and is characterized by severe pain, increased frequency of micturition, and chronic inflammation. Characterizing the molecular fingerprint (gene profile) of IC will help elucidate the mechanisms involved and suggest further approaches for therapeutic intervention. Therefore, in the present study we used established animal models of cystitis to determine the time course of bladder inflammatory responses to antigen, Escherichia coli lipopolysaccharide (LPS), and substance P (SP) by morphological analysis and cDNA microarrays. The specific aim of the present study was to compare bladder inflammatory responses to antigen, LPS, and SP by morphological analysis and cDNA microarray profiling to determine whether bladder responses to inflammation elicit a specific universal gene expression response regardless of the stimulating agent. During acute bladder inflammation, there was a predominant infiltrate of polymorphonuclear neutrophils into the bladder. Time-course studies identified early, intermediate, and late genes that were commonly up-regulated by all three stimuli. These genes included: phosphodiesterase 1C, cAMP-dependent protein kinase, iNOS, beta-NGF, proenkephalin B and orphanin, corticotrophin-releasing factor (CRF) R, estrogen R, PAI2, and protease inhibitor 17, NFkB p105, c-fos, fos-B, basic transcription factors, and cytoskeleton and motility proteins. Another cluster indicated genes that were commonly down-regulated by all three stimuli and included HSF2, NF-kappa B p65, ICE, IGF-II and FGF-7, MMP2, MMP14, and presenilin 2. Furthermore, we determined gene profiles that identify the transition between acute and chronic inflammation. During chronic inflammation, the urinary bladder presented a predominance of monocyte/macrophage infiltrate and a concomitant increase in the expression of the following genes: 5-HT 1c, 5-HTR7, beta 2 adrenergic receptor, c-Fgr, collagen 10 alpha 1, mast cell factor, melanocyte-specific gene 2, neural cell adhesion molecule 2, potassium inwardly-rectifying channel, prostaglandin F receptor, and RXR-beta cis-11-retinoic acid receptor. We conclude that microarray analysis of genes expressed in the bladder during experimental inflammation may be predictive of outcome. Further characterization of the inflammation-induced gene expression profiles obtained here may identify novel biomarkers and shed light into the etiology of cystitis.
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PMID:Gene expression profiling of mouse bladder inflammatory responses to LPS, substance P, and antigen-stimulation. 1205 14

Mutant NF-kappaB-deficient B cells from knockout mice lacking RelA, p105/p50 or the transactivation domain of c-Rel exhibit distinct and selective cell-intrinsic defects in their ability to undergo class switch recombination (CSR) to specific Ig isotypes. This isotype-specific requirement for particular NF-kappaB transcription factors in B cells activated to undergo CSR is intriguing because the NF-kappaB composition in B cells is also highly regulated and can vary significantly depending upon how B cells are activated. These studies prompted us to test by retroviral transduction of normal B cells whether changes in the NF-kappaB composition in activated B cells could modulate cytokine-driven CSR. RelB, RelA, c-Rel, p50 and p52 were first expressed in lipopolysaccharide-activated primary B cells and then induced by cytokine addition to undergo CSR to IgG1, IgE, IgG2a, IgG2b or IgA. Surprisingly, only retroviral expression of RelB altered CSR, resulting in a 3-fold decrease in CSR to IgG1 induced by IL-4. This effect was isotype specific as RelB expression did not affect CSR to IgE within the same culture or to other isotypes tested. The transactivation domain of RelB was required for inhibition of CSR to IgG1. Expression of p50-RelB or p52-RelB dimers joined covalently by a flexible peptide linker also specifically inhibited IgG1 CSR. RelB-mediated inhibition of IgG1 CSR was associated with a decrease in germline gamma1 transcription, but not with changes in proliferation as assayed by CFSE labeling. Thus, RelB complexes can specifically inhibit CSR to IgG1, but not IgE, in activated, primary B cells.
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PMID:Regulation of Ig class switch recombination by NF-kappaB: retroviral expression of RelB in activated B cells inhibits switching to IgG1, but not to IgE. 1220 96

NF-kappaB family of transcription factors plays a pivotal role in regulation of immune and inflammatory responses. NF-kappaB is known to function by binding to the kappaB enhancer and directly activating target gene transcription. Here we demonstrate another function of NF-kappaB, in which the nfkappab1 gene product p105 regulates MAP kinase signaling triggered by the bacterial component lipopolysaccharide. p105 exerts this signaling function by controlling the stability and function of an upstream kinase, Tpl2. In macrophages, Tpl2 forms a stable and inactive complex with p105, and activation of Tpl2 involves its dissociation from p105 and subsequent degradation. Thus, p105 functions as a physiological partner and inhibitor of Tpl2, which provides an example of how a transcription factor component regulates upstream signaling events.
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PMID:NF-kappaB1/p105 regulates lipopolysaccharide-stimulated MAP kinase signaling by governing the stability and function of the Tpl2 kinase. 1266 51

2-Oxo-3,23-isopropylidene-asiatate (AS2006A), a wound-healing asiatate derivative, exerts anti-inflammatory effect. Macrophages produce cytokines that recruit other inflammatory cells and are responsible for the diverse effects of inflammation. In the present study, we comparatively evaluated the cytotoxicity of AS2006A to Raw264.7, H4IIE and L-929 cells as part of the studies on its anti-inflammatory effect. Among the cells examined, AS2006A was selectively cytotoxic to Raw264.7 cells, a macrophage cell line. AS2006A increased the number of cells positively stained with TdT-mediated dUTP nick end labeling (TUNEL), and upregulated the expression of the genes implicated with apoptosis, which included caspase-8, c-myc, iNOS, mdm2, NF-kappaB1, I-kappaBalpha and NF-kappaB p105 genes, as assessed by the membrane DNA array technique. The expression of the genes related with cell cycle control was not changed. Thus, the primary targets of AS2006A in macrophages might include the genes implicated with apoptosis. Immunoblot analysis revealed that AS2006A caused the release of cytochrome c from the mitochondria to the cytoplasm in macrophages. Caspase-3 activity and poly(ADP-ribose) polymerase cleavage were both increased by AS2006A in macrophages, indicating that AS2006A induced apoptosis. Viability of macrophages activated by lipopolysaccharide and their NO production were also decreased by AS2006A in a concentration-dependent manner. These results demonstrated that AS2006A selectively induces apoptosis of macrophages with cytochrome c release, caspase 3 activation and poly(ADP-ribose) polymerase cleavage, and that cytotoxicity of AS2006A to macrophages may contribute to anti-inflammatory and wound-healing effects.
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PMID:2-Oxo-3,23-isopropylidene-asiatate (AS2006A), a wound-healing asiatate derivative, exerts anti-inflammatory effect by apoptosis of macrophages. 1294 39

Regulation of transforming growth factor beta 1 (TGF-beta1) expression remains unclear. Inflammation has been inferred to play a major role in stimulating TGF-beta1 production since high concentrations of TGF-beta1 have been found in the lungs of patients with various diffuse inflammatory lung diseases. To establish an association between inflammation and TGF-beta1 expression, human alveolar epithelial (A549) cells were co-cultured with lipopolysaccharide (LPS), Tumor necrosis factor alpha (TNFalpha), Interleukin 1 beta (IL-1beta) and Interleukin 8 (IL-8) for 12 hours. Total and bioactive TGF-beta1 protein were then measured. A549 cells transiently transfected with a plasmid containing the TGF-beta1 promoter linked to a luciferase reported gene were then co-cultured with the same inflammatory peptides for 12 hours and TGF-beta1 promoter activity determined. Nuclear transcription factors AP-1 (c-jun) or NF-kappa (p65, p50 and p105) were over expressed in A549 cells transiently transfected with the TGF-beta1 promoter and TGF-beta1 promoter activity subsequently measured. Stimulation with inflammatory signals LPS, TNFalpha, IL-1beta, IL-8 resulted in no increase of total or bioactive TGF-beta1 activity above constitutive concentrations in vitro. TGF-beta1 promoter activity was also unchanged from baseline levels in response to the same inflammatory peptides. Expression of c-jun however led to significant increases of TGF-beta1 promoter activity over constitutive levels. In contrast p65 and p105 expression resulted in inhibition of TGF-beta1 promoter activity below baseline levels. We conclude that in a human alveolar epithelial cell line, inflammation does not regulate TGF-beta1 expression. These studies suggest that in lung pathologies such as asthma, lung fibrosis and CLD, TGF-beta1 production may involve pathways independent of inflammatory mediators LPS, TNFalpha, IL-1beta and IL-8.
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PMID:Expression of transforming growth factor beta (TGF-beta1) in human epithelial alveolar cells: a pro-inflammatory mediator independent pathway. 1505 19

NF-kappa B1 p105 forms a high-affinity, stoichiometric interaction with TPL-2, a MEK kinase essential for TLR4 activation of the ERK mitogen-activated protein kinase cascade in lipopolysaccharide (LPS)-stimulated macrophages. Interaction with p105 is required to maintain TPL-2 metabolic stability and also negatively regulates TPL-2 MEK kinase activity. Here, affinity purification identified A20-binding inhibitor of NF-kappa B 2 (ABIN-2) as a novel p105-associated protein. Cotransfection experiments demonstrated that ABIN-2 could interact with TPL-2 in addition to p105 but preferentially formed a ternary complex with both proteins. Consistently, in unstimulated bone marrow-derived macrophages (BMDMs), a substantial fraction of endogenous ABIN-2 was associated with both p105 and TPL-2. Although the majority of TPL-2 in these cells was complexed with ABIN-2, the pool of TPL-2 which could activate MEK after LPS stimulation was not, and LPS activation of TPL-2 was found to correlate with its release from ABIN-2. Depletion of ABIN-2 by RNA interference dramatically reduced steady-state levels of TPL-2 protein without affecting levels of TPL-2 mRNA or p105 protein. In addition, ABIN-2 increased the half-life of cotransfected TPL-2. Thus, optimal TPL-2 stability in vivo requires interaction with ABIN-2 as well as p105. Together, these data raise the possibility that ABIN-2 functions in the TLR4 signaling pathway which regulates TPL-2 activation.
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PMID:ABIN-2 forms a ternary complex with TPL-2 and NF-kappa B1 p105 and is essential for TPL-2 protein stability. 1516 88


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