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)

Nanogram quantities of the bacterial superantigen Staphylococcal Enterotoxin A (SEA) induced significant amounts of extracellular IL-1 alpha and IL-1 beta in human peripheral blood mononuclear cells. Induction of maximal IL-1 alpha and IL-1 beta levels by lipopolysaccharide (LPS) required microgram quantities. LPS induced detectable extracellular IL-1 content within 3-6 hr and maximal levels were detected already after 12 hr. Induction of IL-1 production by SEA showed a delayed release with peak values after 24-48 hr. IL-1 beta was the major species of IL-1 seen in both SEA- and LPS-stimulated culture supernatants. SEA was in general a relatively stronger inducer of extracellular IL-1 alpha than LPS. SEA-induced extracellular IL-1 production in human monocytes was entirely dependent on the presence of T cells, whereas addition of T cells to LPS-stimulated purified human monocytes only marginally enhanced the extracellular IL-1 production. The capacity to induce extracellular IL-1 production in monocytes in response to SEA was high in the CD4+ 45RO+ memory T cell subset, whereas CD4+ 45RA+ naive T cells and CD8+ T cells had lower IL-1-inducing capacity. The T cell help for IL-1 production could not be replaced by a panel of T cell-derived recombinant lymphokines added to SEA-stimulated monocytes, including IFN-gamma and TNF, indicating the participation of cell membrane-bound ligands or hitherto unidentified soluble mediators.
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PMID:Induction of interleukin-1 in human monocytes by the superantigen staphylococcal enterotoxin A requires the participation of T cells. 188 98

The antitumour antibiotic actinomycin D (Act D) and the aminosugar D-galactosamine both enhance the sensitivity of animals to bacterial lipopolysaccharide (LPS). Lipopolysaccharide stimulates macrophage membrane-bound procoagulant activity (MPCA) and tumour necrosis factor-alpha (TNF-alpha) production in vitro. We investigated the effects of LPS combined with either Act D or D-galactosamine on procoagulant and TNF-alpha production in vitro. Actinomycin D directly induced procoagulant on the malignant monocytoid cell line WEHI 265, and synergized with LPS to enhance MPCA on both WEHI 265 cells and thioglycollate-induced peritoneal exudate macrophages. In the presence of Act D, exudate macrophages expressed procoagulant in response to concentrations of LPS 100,000-fold lower than normally required. Pulsing experiments demonstrated that LPS primed these cells within 4 h to respond to Act D, whereas 4 h priming with Act D inhibited subsequent procoagulant induction by LPS. Although its effects on TNF-alpha production were less intense, low levels of Act D more than doubled TNF-alpha produced by LPS-stimulated exudate macrophages. Procoagulant expression and TNF-alpha production were not always co-ordinately expressed; interferon-gamma (IFN-gamma) synergized with LPS to enhance both responses but when IFN-gamma was combined with Act D only procoagulant was upregulated. D-galactosamine failed to affect these macrophage responses. Results indicate different in vivo mechanisms of enhancement of LPS toxicity by these two agents.
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PMID:Actinomycin D upregulates lipopolysaccharide induction of macrophage procoagulant expression and tumour necrosis factor-alpha production. 193 97

Interaction of bacterial lipopolysaccharide (LPS) with monocytes stimulates production of a variety of mediators that are involved in the pathogenesis of septic shock and wound repair. We report here the mechanisms of LPS uptake and intracellular distribution of LPS in human monocytes. Ficoll-Hypaque-purified peripheral mononuclear cells (PBMC) were exposed to LPS from rough Escherichia coli (J5) or to biotin-conjugated LPS (biotin-LPS) from smooth E. coli (0111:B4), or to fluorescein isothiocyanate-conjugated LPS of E. coli (055:B5) at 37 degrees C for various times and processed for electron microscopy, immunocytochemistry, and flow cytometry. Monocytes were identified by the presence of numerous cytoplasmic peroxidase-positive granules or by monoclonal antibodies against monocyte. LPS micelles were identified by their specific bilayer structure, staining of horseradish peroxidase reaction product, or colloidal gold using biotin-LPS or a monoclonal antibody to LPS. Binding of LPS to cell surface was observed 5 min after incubation with LPS. Intracellular localization of LPS micelles was found 30 min following exposure to LPS. Prolonged incubation with LPS increased intracellular LPS. Intracellularly, LPS micelles were found in large membrane-bound vacuoles, in small vesicles, and in the cytoplasm and nucleus. They were also observed in association with the cytomembrane of various organelles. The overall results indicate that LPS may be taken up by monocytes by direct passive diffusion through ruptures of plasma membrane, pinocytosis, and phagocytosis, involving specific and/or nonspecific binding, and suggest that peripheral blood monocytes play an important role in clearance of LPS; that LPS may have broad effects on cell functions; and that the nonspecific binding to various cytomembranes may be destructive to cell organelles and cells in general.
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PMID:Ultrastructural and immunocytochemical study of the uptake and distribution of bacterial lipopolysaccharide in human monocytes. 211 60

Cisplatin, doxorubicin and daunorubicin (drugs which intercalate with DNA) influenced the membrane-bound procoagulant potential of murine thioglycollate-induced peritoneal exudate (TG-PEC) macrophages and the monocytoid cell line WEHI 265, whereas the antimetabolites 5-fluorouracil and methotrexate had no effect. Enhanced procoagulant was not caused by non-specific toxicity of these agents. Cisplatin directly increased the procoagulant expressed on WEHI 265 cells, whereas MPCA on TG-PEC was enhanced only when cisplatin was combined with a second stimulant, either bacterial lipopolysaccharide (LPS) or interferon (IFN gamma). WEHI 265 cells failed to respond to the anthracycline drugs, either alone or in combination with LPS, whereas they enhanced the IFN gamma response. Doxorubicin and daunorubicin increased the LPS response of TG-PEC by approximately 4-fold and the IFN gamma response by approximately 10-fold. Pulsing experiments suggested that the anthracyclines enhanced procoagulant expression by a mechanism different from cisplatin. Daunorubicin primed TG-PEC within 4 hr to respond to low levels of LPS, whereas either LPS or cisplatin primed these cells to respond to cisplatin or LPS respectively. Furthermore, the procoagulant expressed by TG-PEC stimulated by LPS/cisplatin had properties of tissue factor (TF: 50% total activity) and Factor VIIa (50% total procoagulant)-like activities, whereas the predominant procoagulant on LPS/anthracycline activated TG-PEC was TF-like (70% total activity) with weak Factor VIIa and prothrombinase-like properties.
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PMID:Induction of macrophage procoagulant expression by cisplatin, daunorubicin and doxorubicin. 212 Jan 34

The induction of high-rate protein secretion entails increased biogenesis of secretory apparatus organelles. We examined the biogenesis of the secretory apparatus in the B cell line CH12 because it can be induced in vitro to secrete immunoglobulin (Ig). Upon stimulation with lipopolysaccharide (LPS), CH12 cells increased secretion of IgM 12-fold. This induced secretion was accompanied by preferential expansion of the ER and the Golgi complex. Three parameters of the rough ER changed: its area and volume increased 3.3- and 3.7-fold, respectively, and the density of membrane-bound ribosomes increased 3.5-fold. Similarly, the area of the Golgi stack increased 3.3-fold, and its volume increased 4.1-fold. These changes provide sufficient biosynthetic capacity to account for the increased secretory activity of CH12. Despite the large increase in IgM synthesis, and because of the expansion of the ER, the concentration of IgM within the ER changed less than twofold during the differentiation process. During the amplification of the rough ER, the expression of resident proteins changed according to one of two patterns. The majority (75%) of rough microsomal (RM) proteins increased in proportion to the increase in rough ER size. Included in this group were both lumenal proteins such as Ig binding protein (BiP), and membrane proteins such as ribophorins I and II. In addition, the expression of a minority (approximately 9%) of RM polypeptides increased preferentially, such that their abundance within the RM of secreting CH12 cells was increased. Thus, the expansion of ER during CH12 differentiation involves preferential increases in the abundance of a few resident proteins, superimposed upon proportional increases in most ER proteins.
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PMID:Membrane biogenesis during B cell differentiation: most endoplasmic reticulum proteins are expressed coordinately. 233 60

Colorectal liver metastases are a common clinical problem and require more effective therapy. Kupffer cells (KC) perform many important homeostatic functions within the liver and may also possess the ability to mediate tumor cytotoxicity. We investigated the ability of human KC to mediate cytotoxicity against human colon adenocarcinoma targets (HT 29) in vitro. Unstimulated human KC were cytotoxic against the HT 29 targets at all effector/target ratios tested. This cytotoxicity was increased significantly (p less than 0.05) when the KC were stimulated with interferon-gamma and lipopolysaccharide. Human KC produced tumor necrosis factor (TNF), and KC stimulation significantly (p less than 0.05) increased secretion of this monokine. The addition of anti-TNF antibody to the KC-HT 29 cocultures completely neutralized all of the available TNF yet cytotoxicity was not affected, suggesting the participation of a membrane-bound form of TNF or other mechanisms.
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PMID:Human Kupffer cells are cytotoxic against human colon adenocarcinoma. 238 33

Studies of the cross-reactivity of antibodies to core glycolipid with assorted isolated, heterologous lipopolysaccharides (LPSs) confirm the conservation of core glycolipid epitopes among gram-negative bacterial species. However, the accessibility of core glycolipid epitopes to antibody in the intact bacterial cell may be affected by the cell surface structure. In studies with 125I-labeled monoclonal antibodies to core glycolipid that cross-react with isolated LPS, the degree to which antibodies can bind to LPS in the outer membrane of intact, viable, gram-negative bacterial cells was found to vary with the strain of bacteria tested. Sequestration of bacterial cell-bound LPS from antibody was confirmed in a smooth strain of Escherichia coli by means of immunoelectron microscopy. The inability of antibody to bind to membrane-bound LPS suggests that such sequestered LPS may also be unable to effect toxicity in the infected host until liberated by bacterial cell breakdown.
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PMID:Reactivity of antibodies to core glycolipid with gram-negative bacteria. 244 71

Human blood monocytes isolated by centrifugal elutriation from healthy donors were tested for ability to produce membrane-associated IL-1 in response to activation stimuli such as various types of interferons (alpha, beta and gamma) and/or synthetic des-methyl muramyl dipeptide (norMDP). When monocytes were treated with norMDP or lipopolysaccharide (LPS) for 16 hr, they released IL-1 into their culture supernatant. When these activated monocytes were fixed with paraformaldehyde (PFA), they stimulated blastogenic responses of C3H/HeJ mouse thymocytes to PHA, suggesting that membrane-associated IL-1 could be induced by norMDP or LPS. Membrane-associated IL-1 was also found to be induced by the synergistic actions of suboptimal concentrations of rIFN-gamma and nor MDP, but not of rIFN-alpha A or rIFN-beta with norMDP. A specific anti-IL-1 alpha antiserum completely inhibited membrane-associated IL-1 activity, but did not affect the thymocyte-stimulating activity of fixed monocytes. IL-1 alpha was detected by fluorescence staining using the anti-IL-1 alpha antiserum on monocytes fixed after gamma IFN-gamma and norMDP. These results suggest that IFN-gamma may be important in expression of membrane-bound IL-1 alpha by the human blood monocytes responsible for regulation of immune responses in vivo.
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PMID:Induction of membrane-associated interleukin 1 alpha (IL-1 alpha) by synergistic activation of human blood monocytes with interferon gamma and muramyl dipeptide analog. 248 23

The immunosuppressive drug Cyclosporin A (CyA) inhibited the ConA-induced DNA synthesis in C57B1/6 spleen cells at a concentration of 40 ng/ml totally; this inhibition could not be overcome by the addition of highly purified interleukin-1. ConA-induced RNA synthesis was also inhibited by concentrations of 40 or 200 ng/ml CyA, although total inhibition could not be achieved. In contrast, lipopolysaccharide-induced proliferation could not be inhibited. CyA at a concentration of 40 ng/ml also inhibited the ConA-induced production of interleukin-2 by mouse spleen cells, this inhibition was not due to a toxic mechanism. On the contrary, the proliferative response of T cell blasts from a long-term T cell line (M2) to interleukin-2 containing supernatants was not inhibited by concentrations of 40 or 200 ng/ml CyA; only at 20-100-fold higher concentrations partial inhibition could be observed. One of the earliest events in the course of lymphocyte activation, the enhanced incorporation of unsaturated fatty acids into the lymphocyte plasma membranes; was also inhibited by concentrations of CyA, which abrogated the ConA-induced DNA synthesis. The inhibition of the enhanced incorporation of 14C-oleic acid and 14C-linoleic acid, which are incorporated by the membrane-bound lysolecithin-acyltransferase, thus suggests a molecular site of action for CyA.
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PMID:Studies on the mechanism whereby cyclosporin A inhibits T-lymphocyte activation. 258 Jul 77

Membrane proteins from murine lymphoblasts enriched by the Triton-X114 procedure were analysed by 2-dimensional gel electrophoresis to reveal proteins differentially expressed in mitogen-reactive subpopulations of B cells. The protein patterns from C57BL/6 normal and nude mice and from the B10.Sc.Cr LPS-non-responder strain, activated with lipopolysaccharide (LPS) or an analogue of lipoprotein, were virtually identical when run under strictly parallel conditions. These experiments raise the question as to whether mitogen receptors, serologically and functionally found to be membrane-bound, do exist as membrane proteins.
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PMID:The membrane protein compositions of lipopolysaccharide- or lipoprotein-activated B lymphoblasts from C57BL LPS-responder and non-responder mice are qualitatively indistinguishable. 259 80


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