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

Transcriptional activation of various genes by lipopolysaccharide (LPS) is known to be mediated, at least in part, by the NF-kappa B/Rel family of transcription factors. We have identified a novel kappa B element located immediately downstream of the TNF-alpha gene that is conserved together with its flanking sequences across species lines and can act as an LPS-responsive enhancer for reporter gene constructs driven by the minimal TNF promoter. In extracts from activated murine macrophages and macrophage cell lines this element binds several non-canonical NF-kappa B/Rel complexes, in addition to p50 (NFKB1) homodimer and p50-p65 (NKFB1-RelA) heterodimer. Combination of high-resolution electrophoretic mobility shift assays (EMSA) with monospecific antibodies and u.v.-cross-linking indicates that the prominent slow migrating complex III contain p65 homodimer and c-Rel. The appearance of complex III in EMSA parallels the translocation of p65 and c-Rel into the nucleus and occurs shortly after LPS induction. Transfection experiments with reporter constructs driven by this kappa B element indicate strong inducibility by LPS and p65, moderate inducibility by c-Rel and repression by p50. Functional activity of sandwich TNF-CAT-TNF constructs further suggests that LPS-inducible transcriptional activation of the TNF gene in murine macrophages may be partly mediated by a downstream enhancer.
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PMID:Conserved kappa B element located downstream of the tumor necrosis factor alpha gene: distinct NF-kappa B binding pattern and enhancer activity in LPS activated murine macrophages. 762 37

The interleukin-6 (IL-6) gene expression in bovine monocytes is highly induced following bacterial lipopolysaccharide (LPS) stimulation. To identify the promoter element(s) involved in the inducible transcription of IL-6, a 5'-flanking region containing 230 bp of the bovine IL-6 gene was linked to a reporter gene coding for bacterial chloramphenicol acetyltransferase (CAT) and analyzed for its ability to confer LPS-responsiveness to the reporter CAT gene in monocytic cells. Using mutant reporter genes, we demonstrate that although mutation in the NF-kappa B element produces the major loss of induction, both NF-kappa B and C/EBP elements are necessary for maximal transcriptional activation of the bovine IL-6 gene. Gel electrophoretic mobility-shift assays have detected induced DNA-binding activities in the LPS-stimulated monocytes. Further characterization has revealed the activation and interaction of C/EBP-alpha, C/EBP-beta (NF-IL6), NFKB1 (p50), and RelA (p65) to their specific binding elements present in the bovine IL-6 gene. These results suggest a model in which induction of C/EBP-alpha in differentiating monocytes contributes and synergizes with induced C/EBP-beta and NF-kappa B, which are activated following LPS stimulation, to mediate a high rate of IL-6 transcription under inflammatory conditions.
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PMID:Lipopolysaccharide-mediated induction of the bovine interleukin-6 gene in monocytes requires both NF-kappa B and C/EBP binding sites. 766 56

Intracellular protein phosphorylation is thought to be the initial step in cell activation. Bacterial lipopolysaccharide (LPS) induces a special set of the protein phosphorylation in the murine peritoneal macrophages, including p65 (molecular mass of 65 kDa) which is a substrate of serine kinase and the most dominant phosphorylated cytosolic protein. This article deals with the relation between the LPS-induced protein phosphorylation in the murine peritoneal macrophages and their productions of IL-1 beta and TNF-alpha. LPS-induced p65 phosphorylation seems to be dependent on protein kinase C (PKC) and calmodulin (CaM), because it diminishes in the presence of inhibitors to PKC or CaM. Tyrosine kinase inhibitors do not affect the p65 phosphorylation. The PKC inhibitors also affect the mRNA expressions and the productions of active molecules of IL-1 beta and TNF-alpha. Though the CaM inhibitor inhibits the mRNA expression and the active molecule production of IL-1 beta, it does not affect those of TNF-alpha. These results suggest that LPS-induced p65 phosphorylation is closely related to PKC and CaM, and that IL-1 beta production depends on PKC and CaM, while the TNF-alpha production is not dependent on CaM. These findings indicate the existence of multiple pathways and different regulatory mechanisms for transduction of LPS signal in the macrophages. Furthermore, LPS-induced phosphorylation is not observed in endotoxin tolerant macrophages after re-stimulation with LPS, suggesting that the LPS-stimulus signal is blocked at a site in the signal transduction-pathway before the point of phosphorylation of proteins in the tolerant macrophages.
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PMID:Intracellular protein phosphorylation in murine peritoneal macrophages in response to bacterial lipopolysaccharide (LPS): effects of kinase-inhibitors and LPS-induced tolerance. 768 35

Vascular cell adhesion molecule 1 (VCAM-1) is expressed in both endothelial and epithelial cell types, where it contributes to lymphocyte migration to sites of inflammation. Its expression is regulated by cytokines, in part through two kappa B-like regulatory elements. Because NF-kappa B can be composed of multiple alternative subunits with differential effects on gene expression, the role of different specific NF-kappa B family members subunits in VCAM-1 regulation is unknown. In this report, we define the contribution of different NF-kappa B family members to VCAM-1 gene regulation. We show that both kappa B sites in the VCAM-1 enhancer are required to optimally stimulate gene expression, but the enhancer is differentially regulated by specific combinations of NF-kappa B subunits. At low concentrations, RelA(p65) acted in concert with the approximately 50-kDa product of p105 NF-kappa B, NF-kappa B1(p50), to stimulate transcription, and at high concentrations, RelA(p65) alone stimulated the VCAM-1 promoter. In contrast, NF-kappa B2 inhibited functional activation of the VCAM reporter by p65. Consistent with this finding, an additional binding complex was detected by using recombinant NF-kappa B2(p49)/RelA(p65) with radiolabeled VCAM kappa B site probes. Interestingly, the human immunodeficiency virus enhancer responded differently to stimulation by NF-kappa B subunits, with optimal response to p49(100)/p65. Analysis of NF-kappa B mRNA in human umbilical vein endothelial cells revealed that nfkb1, nfkb2, and relA NF-kappa B but not c-rel were induced by tumor necrosis factor alpha and lipopolysaccharide, which also induce VCAM-1. These data suggest that specific subunits of NF-kappa B regulate VCAM-1 and differentially activate other genes in these cells.
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PMID:Differential regulation of vascular cell adhesion molecule 1 gene expression by specific NF-kappa B subunits in endothelial and epithelial cells. 769 29

The transcription factor NF-kappa B, shown to be essential for expression of the immunoglobulin C kappa gene, is a key regulatory component in pre-B to B-cell differentiation. While previous studies have used lymphoid cell line models, here we examine the expression and subunit composition of rel/NF-kappa B complexes in normal murine pre-B and B lymphocytes. Two major NF-kappa B complexes are detected in pre-B and B cells. A high mobility complex, found in pre-B (Cb) and B cells (C beta) is a homodimer of the NF-kappa B subunit p50. In pre-B cells, the slower migrating complex (Ca), which is predominantly cytoplasmic, is largely comprised of p50 and p65, whereas in B cells, a nuclear and cytoplasmic complex (C alpha) of identical mobility to Ca mainly consists of p50 and p75c-rel. While p50 and p65 levels do not change during pre-B to B-cell differentiation, p75c-rel is 5- to 6-fold more abundant in B cells compared to pre-B cells, a finding consistent with the switch in NF-kappa B subunit usage. During lipopolysaccharide-induced B-cell proliferation, transient up-regulation of both the nuclear p50 homodimer and p75c-rel containing complex is mirrored by a concurrent increase in c-rel and p105 but not p65 mRNA expression, a finding consistent with rel-NF-kappa B expression in B cells being controlled by an autoregulatory mechanism.
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PMID:The subunit composition of NF-kappa B complexes changes during B-cell development. 769 80

The promoter region of the rabbit serum amyloid A (SAA) gene contains two adjacent C/EBP and one NF-kappa B binding element. Involvement of these elements in SAA gene induction, following lipopolysaccharide (LPS) stimulation of the liver, has been studied by investigating LPS-activated transcription factors and their interaction with the promoter elements of the SAA gene. Appearance of complexes in the electrophoretic mobility shift assay has indicated that DNA-binding proteins that interact with the NF-kappa B element of the SAA promoter are induced in the LPS-treated rabbit liver. Presence of RelA (p65 subunit of NF-kappa B) in these complexes was demonstrated by the ability of RelA-specific antisera to supershift the DNA-protein complexes. LPS also induced several members of the C/EBP family of transcription factors, which interacted with the C/EBP motifs of the SAA promoter. Activated C/EBP and RelA form a RelA-C/EBP heteromeric complex that associates with varying affinity to NF-kappa B and C/EBP elements of the SAA gene. Transfection assays using both transcription factor genes have demonstrated that the heteromeric complex of NF-kappa B and C/EBP is a much more potent transactivator of SAA expression than each transcription factor alone. The heteromeric complex efficiently promotes transcription from both NF-kappa B and C/EBP sites.
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PMID:Concerted participation of NF-kappa B and C/EBP heteromer in lipopolysaccharide induction of serum amyloid A gene expression in liver. 770 80

Mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) is involved in trafficking of lymphocytes to mucosal endothelium. Expression of MAdCAM-1 is induced in the murine endothelial cell line bEnd.3 by tumor necrosis factor alpha (TNF-alpha), interleukin 1, and bacterial lipopolysaccharide. Here we show that TNF-alpha enhances expression of a firefly luciferase reporter directed by the MAdCAM-1 promoter, confirming transcriptional regulation of MAdCAM-1. Mutational analysis of the promoter indicates that a DNA fragment extending from nt -132 to nt +6 of the gene is sufficient for TNF-alpha inducibility. Two regulatory sites critical for TNF-alpha induction were identified in this region. DNA-binding experiments demonstrate that NF-kappa B proteins from nuclear extracts of TNF-alpha-stimulated bEnd.3 cells bind to these sites, and transfection assays with promoter mutants of the MAdCAM-1 gene indicate that occupancy of both sites is essential for promoter function. The predominant NF-kappa B binding activity detected with these nuclear extracts is a p65 homodimer. These findings establish that, as with other endothelial cell adhesion molecules, transcriptional induction of MAdCAM-1 by TNF-alpha requires activated NF-kappa B proteins.
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PMID:Induction of the gene encoding mucosal vascular addressin cell adhesion molecule 1 by tumor necrosis factor alpha is mediated by NF-kappa B proteins. 772 98

Tissue factor (TF) expression by endothelial cells is implicated in thrombotic episodes in patients with a variety of clinical disorders. In a baboon model of lethal sepsis, TF is expressed by endothelial cells in the splenic microvasculature. In vitro, endothelial cells are induced to express TF in response to tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and bacterial endotoxin (lipopolysaccharide [LPS]). Here, we identified cis-acting regulatory elements that control TF gene transcription in primary human endothelial cells. Functional studies showed that the TF promoter contained a 56-bp enhancer (-227 to -172 bp), which included two activator protein-1 (AP-1) sites and a kappa B-like site, that mediated induction by TNF-alpha, IL-1 beta, and LPS. Electrophoretic mobility shift assays demonstrated that endothelial cells contained constitutive AP-1 binding activity, whereas the kappa B-like site, 5'-CGGAGTTTCC-3', bound an inducible nuclear complex composed of c-Rel-p65 heterodimers. Taken together, our data suggest that induction of TF gene transcription in endothelial cells is mediated by functional interactions between Fos-Jun and c-Rel-p65 heterodimers.
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PMID:Transcriptional regulation of tissue factor expression in human endothelial cells. 774 75

Intercellular adhesion molecule-1 (ICAM-1) is greatly up-regulated on endothelial cells at sites of inflammation and is involved in leukocyte attachment and extravasation. Previously, we had shown that the ICAM-1 gene expression in human umbilical vein endothelial cells (HUVECs) was transcriptionally regulated by tumor necrosis factor-alpha (TNF-alpha) (Wertheimer, S. J., Myers, C. L., Wallace, R. W., and Parks, T. P. (1992) J. Biol. Chem. 267, 12030-12035). In the present investigation, TNF-alpha-induced transcription was found to be initiated exclusively at two sites, 40 and 41 base pairs upstream of the translation start site. Deletion analysis of the 5' regulatory region of the ICAM-1 gene revealed a 92-base pair sequence which was both necessary and sufficient to confer TNF-alpha responsiveness to a linked luciferase reporter gene in transient transfection assays. This TNF-alpha-responsive region contained a variant NF-kappa B site at -187 to -178, which when mutated, completely abolished ICAM-1 promoter activation by TNF-alpha, interleukin-1 beta, and lipopolysaccharide. Two inducible nuclear protein complexes bound to the ICAM-1 kappa B and were identified as the NF-kappa B p65 homodimer and p65/p50 heterodimer. Overexpression of p65, but not p50, transactivated the ICAM-1 promoter in a kappa B site-dependent manner in HUVECs. In addition, p65-mediated transactivation was suppressed by co-expression of p50. Our results suggest that cytokine activation of the ICAM-1 promoter in HUVECs may critically depend on p65 homodimers binding to a variant kappa B site.
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PMID:Transcriptional regulation of the intercellular adhesion molecule-1 gene by inflammatory cytokines in human endothelial cells. Essential roles of a variant NF-kappa B site and p65 homodimers. 782 33

The effects of bacterial lipopolysaccharide (LPS) on macrophage gene expression are mediated in part by its ability to induce activation of transcription factor NF-kappa B. We compared the ability of LPS-treated macrophages from Lpsn (LPS-responsive) C3H/HeN and Lpsd (LPS-hyporesponsive) C3H/HeJ mice to mobilize NF-kappa B by electrophoretic mobility shift assays with oligonucleotide probes containing a unique NF-kappa B sequence from the promoter of inducible nitric oxide synthase (iNOS). In response to ng/ml concentrations of LPS, this probe bound proteins that appeared rapidly in the nuclei of thioglycollate-elicited macrophages and bone marrow-derived macrophage cell lines from both Lpsn and Lpsd mice. Only in macrophages from Lpsn mice, however, was LPS able to induce iNOS or tumor necrosis factor alpha. NF-kappa B-containing DNA-protein complexes from Lpsd macrophages were formed in lesser amounts than from Lpsn macrophages but shared the same composition, insofar as they displayed the same electrophoretic mobilities and content of heterodimers of p50/RelA (p65) and p50/c-rel. Two conclusions emerge from these findings: (1) NF-kappa B activity alone is not sufficient for induction of certain LPS-responsive genes and (2) An LPS-response pathway involving activation of NF-kappa B is preserved in Lpsd mice. The inability of cells from Lpsd mice to induce gene expression in response to LPS thus cannot be attributed to inability to activate NF-kappa B.
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PMID:Macrophages derived from C3H/HeJ (Lpsd) mice respond to bacterial lipopolysaccharide by activating NF-kappa B. 782 69


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