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)

The human CC chemokine CCL16, a liver-expressed chemokine, enhances the killing activity of mouse peritoneal macrophages by triggering their expression of tumor necrosis factor alpha (TNF-alpha) and Fas ligand. Macrophages also respond to CCL16 by enhancing their production of monocyte chemoattractant protein-1, regulated on activation, normal T cells expressed and secreted chemokines, and interleukin (IL)-1 beta, TNF-alpha, and IL-12. The effect of CCL16 is almost as strong as that of lipopolysaccharide and interferon-gamma, two of the best macrophage activators. Moreover, CCL16-activated macrophages overexpress membrane CD80, CD86, and CD40 costimulatory molecules and extensively phagocytose tumor cell debris. On exposure to such debris, they activate a strong, tumor-specific, cytolytic response in virgin T cells. Furthermore, cytolytic T cells generated in the presence of CCL16 display a higher cytotoxicity and activate caspase-8 in tumor target cells. This ability to activate caspase-8 depends on their overexpression of TNF-alpha and Fas ligand induced by CCL16. These data reveal a new function for CCL16 in the immune-response scenario. CCL16 significantly enhances the effector and the antigen-presenting function of macrophages and augments T cell lytic activity.
 ...
PMID:CCL16/LEC powerfully triggers effector and antigen-presenting functions of macrophages and enhances T cell cytotoxicity. 1452 62

Trichothecene mycotoxins cause immunosuppression by inducing apoptosis in lymphoid tissue. Trichothecene-induced leukocyte apoptosis can be augmented by bacterial lipopolysaccharide (LPS) but the mechanisms involved in this potentiating effect are not completely understood. The objective of this study was to test the hypothesis that the trichothecene deoxynivalenol (DON, vomitoxin) can interact with LPS directly and other mediators or agonists associated with immune/inflammatory responses to induce apoptosis in primary murine leukocyte cultures. Primary leukocyte suspensions were prepared from murine thymus (TH), spleen (SP), bone marrow (BM) and Peyer's patches (PP) and then cultured with DON in the absence or presence of LPS, prostaglandin E2 (PGE2), anti-immunoglobulin (as antigen mimic), dexamethasone, Fas ligand, or TNF-alpha. Cytotoxicity and apoptosis were evaluated by MTT assay and morphologic assays, respectively. DON was found to inhibit LPS-induced proliferation and dexamethasone-induced apoptosis in SP cultures. In contrast, potentiation of DON-induced apoptosis and cytotoxicity was observed in BM cultures treated with anti-Fas and in TH cultures treated with TNF-alpha. When potentiation of DON-induced apoptosis by TNF-alpha was assessed using pharmacological inhibitors, generation of ROS, intracellular Ca2+, p38/SAPK, and caspase-3 activation were found to play roles. Taken together, these data demonstrate that LPS and its downstream mediators can interact with trichothecenes to modulate proliferative, cytotoxic and apoptotic outcomes in leukocytes in a tissue-specific manner.
 ...
PMID:Potentiation of trichothecene-induced leukocyte cytotoxicity and apoptosis by TNF-alpha and Fas activation. 1459 25

The nonapoptotic functions of Fas ligation are incompletely characterized. In contrast to expectations, we show here that Fas-deficient mice developed less-severe collagen-induced arthritis than did control mice. Despite having milder arthritis, Fas-deficient mice had more of the critical pro-inflammatory mediator interleukin-1 beta (IL-1 beta) in their joints, suggesting inefficient activation through IL-1 receptor 1 (IL-1R1) when Fas signaling is deficient. In primary human macrophages and macrophages from Fas- or Fas ligand (FasL)-deficient mice, interruption of Fas-FasL signaling suppressed nuclear factor-kappa B activation and cytokine expression induced by IL-1 beta and lipopolysaccharide. This cross-talk was mediated by the Fas-associated death domain through interaction with myeloid differentiation factor 88. These observations document a unique mechanism whereby Fas-FasL interactions enhance activation through the IL-1R1 or Toll-like receptor 4 pathway, which may contribute to the pathogenesis of chronic arthritis.
 ...
PMID:Fas ligation on macrophages enhances IL-1R1-Toll-like receptor 4 signaling and promotes chronic inflammation. 1500 57

To determine whether the Fas/Fas ligand (FasL) (CD95/CD178) system contributes to the development of an inflammatory response in vivo, 2.5 microg of bacterial lipopolysaccharide (LPS; endotoxin) per g was administered intranasally to healthy mice (C57BL/6) and mutant mice deficient in either Fas (lpr mice) or FasL (gld mice). Sustained LPS-induced neutrophilic inflammation in the lungs was attenuated in both lpr and gld mice. These observations provide further evidence of a proinflammatory role for the Fas/FasL system in the lungs.
 ...
PMID:Sustained lipopolysaccharide-induced lung inflammation in mice is attenuated by functional deficiency of the Fas/Fas ligand system. 1501 88

Normal spontaneous apoptosis in neutrophils is enhanced by "stress" stimuli such as tumor necrosis factor-alpha, Fas ligand, and oxidants, and this effect is inhibited by anti-apoptotic stimuli including granulocyte-macrophage colony-stimulating factor, lipopolysaccharide, and formylmethionine-leucine-phenylalanine. In this report we demonstrate that anti-apoptotic stimuli protect neutrophils from stress-induced apoptosis via activation of the ERK/MAPK pathway. The protection occurs downstream of mitochondrial alterations assessed as a decrease in membrane potential concomitant with enhanced cytochrome c release. ERK activation was shown to inhibit apoptosis by maintaining levels of XIAP, which is normally decreased in the presence of the pro-apoptotic/stress stimuli. This report also demonstrates that potent intra- and extracellular oxidants inhibit the protective effect of ERK. Oxidant-dependent inhibition of ERK was because of activation of p38 MAPK and activation of the protein phosphatases PP1 and PP2A. Our data suggest that ERK suppresses stress-induced apoptosis downstream of mitochondrial alterations by maintaining XIAP levels and that oxidants block this effect through activation of p38 and protein phosphatases.
 ...
PMID:Oxidants inhibit ERK/MAPK and prevent its ability to delay neutrophil apoptosis downstream of mitochondrial changes and at the level of XIAP. 1529 76

Decoy receptor 3 (DcR3), a soluble receptor in the tumor necrosis factor (TNF) receptor family, is known to inhibit apoptosis mediated by pro-apoptotic TNF family cytokines such as Fas ligand (FasL), TL1A, and LIGHT. Therefore, the regulation of DcR3 expression under certain pathophysiological conditions is of interest since the level of soluble DcR3 would most likely affect the homeostasis of cells and tissues. We found that human intestinal epithelial cell (IEC) lines (SW480, SW620, and HT29) could selectively increase DcR3 release in response to lipopolysaccharide (LPS) and that all the cells preferentially expressed Toll-like receptor 4 (TLR-4). LPS-induced DcR3 releases in IECs appeared to be via the activation of mitogen-activated protein kinases (MAPK) such as extracellular signal-regulated kinase 1 and 2 (ERK1/2) and c-Jun NH2-terminal protein kinase (JNK), and the transcription factor NF-kappaB. Moreover, the increased expression of DcR3 in appendix epithelia from patients with acute appendicitis was demonstrated. Taken together, the results indicated that DcR3 might play an important role in the human intestinal epithelium during acute inflammatory processes caused by endotoxin challenge.
 ...
PMID:Increased expression of soluble decoy receptor 3 in acutely inflamed intestinal epithelia. 1589 96

Trypanosoma musculi-macrophage co-cultures were studied to investigate the biological role of lipopolysaccharide (LPS) induced cytokines in controlling the proliferation of parasites in vitro. Macrophages, isolated by peritoneal lavage, sustained the growth and proliferation of the parasites. Macrophages activated with LPS were characterized by up-regulation of nitric oxide synthase (iNOS) and phagocytosis of fluorescent latex spheres. Activated macrophages showed marked inhibition of the association and proliferation of the parasites. The LPS treated macrophages produced cytokines, especially interferon gamma (INF-gamma), which was detected by Western blot. Trypanosomes, inhibited from association with macrophages, did not proliferate and instead formed clusters held together by their flagella. Cells in these clusters were apoptotic, as demonstrated by the Apoptag reaction and gel fragmentation assay. In addition, high levels of caspase 8 and caspase 3 were shown in floating trypanosome clusters. The results would suggest that INF-gamma and other cytokines released by activated macrophages, possibly functioning through the INF-gammaR1, Fas ligand, CD95 or other death ligands in the trypanosome plasma membrane initiates the apoptosis cascade in trypanosomes.
 ...
PMID:Apoptosis of Trypanosoma musculi co-cultured with LPS activated macrophages: enhanced expression of nitric oxide synthase INF-gamma and caspase. 1633 91

To characterize the roles of Porphyromonas gingivalis and its components in disease processes, we investigated the cytokine profiles induced by live P. gingivalis, its lipopolysaccharide (LPS), and its major fimbrial protein, fimbrillin (FimA). A cytokine antibody array revealed that human monocyte-derived macrophages were induced to produce chemokines (e.g., monocyte chemoattractant protein 1, macrophage inflammatory protein 1beta [MIP-1beta], and MIP-3alpha) as early as 1 h after exposure to P. gingivalis, with production declining after 24 h of exposure. As expected, an extensive repertoire of inflammatory mediators increased subsequent to infection, most predominantly tumor necrosis factor alpha (TNF-alpha), interleukin 1beta (IL-1beta), IL-6, IL-10, and granulocyte-macrophage colony-stimulating factor. The induction of cytokines by P. gingivalis was not triggered simply by bacterial cell surface components, since purified P. gingivalis LPS and FimA induced similar patterns of cytokines, while the pattern of cytokines induced by live P. gingivalis was significantly different, indicating that the host defense system senses live bacteria differently than it does the cell surface components LPS and FimA. To further understand the mechanisms by which live P. gingivalis and its components exert their effects, we used a high-throughput immunoblot screening approach (Becton-Dickinson PowerBlot) to analyze intracellular proteins involved in P. gingivalis infection in human macrophages. Exposure of human macrophages to either live P. gingivalis, its LPS, or its FimA protein led to the up-regulation of 12, 8, and 10 proteins and the down-regulation of 15, 8, and 17 proteins, respectively. The expression of proteins involved in gene transcription (e.g., monocyte enhancer factor 2D [MEF2D], signal transducer and activator of transcription 1 [STAT1], STAT3, STAT6, and IL enhancer binding factors [ILF3]), of protein kinases (e.g., mitogen-activated protein kinase 3 [MAPK3], MAP3K8, double-stranded RNA-activated protein kinase [PRKR], and MAP2K4), and of proteins involved in immune responses (e.g., TNF super family member 6 [TNFSF6] and interferon-induced protein with tetratricopeptide repeat 4 [IFIT4]), apoptosis (e.g., genes associated with retinoid interferon-induced mortality 19 [GRIM19]), and other fundamental cellular processes (e.g., clathrin heavy-chain polypeptide, culreticulin, and Ras-associated protein RAB27A) was found to be modulated differentially by P. gingivalis, LPS, and FimA. These differential changes are interpreted as preferential signal pathway activation in host immune/inflammatory responses to P. gingivalis infection.
 ...
PMID:Identification of proteins differentially expressed in human monocytes exposed to Porphyromonas gingivalis and its purified components by high-throughput immunoblotting. 1642 70

The effect of interferon (IFN)-gamma and/or lipopolysaccharide (LPS) on Fas-mediated cell death with anti-Fas agonistic antibody in vascular endothelial cells was examined using a mouse END-D cell line. Anti-Fas agonistic antibody exhibited cytotoxic actions on END-D cells. Fas-mediated cell death was enhanced by LPS or IFN-gamma. The combination of IFN-gamma and LPS significantly enhanced cell death compared to IFN-gamma or LPS alone. IFN-gamma and LPS augmented cell surface expression of Fas, but not tumour necrosis factor (TNF) receptor 1. Inhibitors of p38 mitogen-activated protein kinase (MAPK) prevented augmentation of Fas expression in IFN-gamma and LPS-treated END-D cells. IFN-gamma and LPS-treated END-D cells did not become susceptible to TNF-alpha or nitric oxide-mediated cytotoxicity. IFN-gamma and LPS thus appear to augment selectively Fas expression via activation of p38 MAPK and enhance Fas-mediated cell death in END-D cells. Furthermore, administration of IFN-gamma and LPS into mice induced in vivo expression of Fas on vascular endothelial cells and Fas ligand (FasL) on peripheral blood leucocytes. The relationship between enhancement of Fas-mediated cell death by IFN-gamma and LPS and the development of vascular endothelial injury is discussed.
 ...
PMID:Lipopolysaccharide and interferon-gamma enhance Fas-mediated cell death in mouse vascular endothelial cells via augmentation of Fas expression. 1790 Mar 5

Alveolar epithelial cell death plays a crucial role in the progression of acute lung injury. We have demonstrated up-regulation of Fas expression on alveolar epithelial cells, and soluble Fas ligand secretion from inflammatory cells upon acute lung injury. Here we show that the lipopolysaccharide-stimulated human monocyte cell line THP-1 releases Fas ligand, and that conditioned medium from lipopolysaccharide-stimulated THP-1 cells induces apoptosis of the human pulmonary adenocarcinoma cell line A549. Activation of caspase-3 and -8 is associated with the apoptosis. Gene targeting on Fas in A549 cells by specific small interfering RNA impairs apoptosis induced by conditioned medium from activated THP-1, while that on Fas ligand in THP-1 cells impairs the apoptosis-inducing activity of the conditioned medium produced by lipopolysaccharide-stimulated cells. These results suggest that Fas ligand released by monocytes causes alveolar epithelial cell death through a Fas-dependent apoptotic mechanism in the development of acute lung injury.
 ...
PMID:Fas ligand released by activated monocytes causes apoptosis of lung epithelial cells in human acute lung injury model in vitro. 1831 Aug 97


<< Previous 1 2 3 4 5 6 Next >>