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)

Neutrophil (polymorphonuclear leukocyte [PMN]) sequestration is one of the histologic hallmarks of an acute inflammatory response. During the natural evolution of an inflammatory response, PMNs are often replaced by mononuclear cells. This shift in the elicitation of specific leukocyte populations usually occurs as the inflammatory lesion enters either the repair/resolution stage or progresses to a chronic inflammation. To elucidate a potential mechanism for the temporal change from predominantly PMN recruitment to the presence of monocytes, we postulated that PMNs could be a rich source of monocyte chemotactic factors. In our studies, we have identified a dose-dependent induction of monocyte chemotactic activity by PMNs treated with lipopolysaccharide (LPS; 1-100 ng/ml). Interestingly, this monocyte chemotactic activity was significantly attenuated in the presence of neutralizing anti-human macrophage inflammatory protein 1 alpha (MIP-1 alpha) antibodies. Moreover, immunolocalization studies demonstrated the expression of MIP-1 alpha by stimulated PMNs. These findings showed that a significant amount of PMN-derived monocyte chemotactic activity was attributable to MIP-1 alpha. Subsequent characterization of MIP-1 alpha steady-state mRNA and antigen expression demonstrated both a dose- and time-dependent production by LPS-treated PMNs. Granulocyte/macrophage colony-stimulating factor (GM-CSF), a potent PMN activator, failed to induce the expression of MIP-1 alpha over a wide range of concentrations. However, PMNs stimulated in the presence of both LPS and GM-CSF resulted in a synergistic expression pattern for MIP-1 alpha. PMNs stimulated in the presence of both GM-CSF and LPS demonstrated an enhanced and prolonged expression for both MIP-1 alpha mRNA and antigen, as compared with LPS alone. Messenger RNA stabilization analyses demonstrated that MIP-1 alpha mRNA isolated from PMNs stimulated in the presence of GM-CSF and LPS had a prolonged mRNA t1/2, as compared with LPS alone. These findings support the notion that PMNs are capable of producing MIP-1 alpha in the presence of LPS, and that GM-CSF can influence this production through prolongation of MIP-1 alpha mRNA t1/2. The production of PMN-derived MIP-1 alpha, in association with the expression of appropriate adhesion molecules at a site of inflammation, may be one of the central events that contributes to the temporal shift from predominantly PMNs to monocytes during the evolution of inflammation.
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PMID:Expression and regulation of human neutrophil-derived macrophage inflammatory protein 1 alpha. 831 95

Using flow cytometric methods, the influence of recombinant human macrophage colony-stimulating factor (rhM-CSF) on DNA synthesis, the phagocytosis of microspheres and the uptake of lipopolysaccharide (LPS) in cultured rat Kupffer cells was investigated. Incubation with 10(3) U/ml of rhM-CSF did not increase the S-phase population of Kupffer cells, however, 10(5) U/ml of M-CSF significantly increased that population from 6.26 +/- 0.68% to 8.31 +/- 0.99%. Significantly increased rate of cells phagocytosing microspheres was provoked by rhM-CSF at concentration higher than 10(3) U/ml. Uptake indexes at concentrations of 10(3), 10(4), 10(5), and 10(6) U/ml of rhM-CSF were 114.2 +/- 7.7, 116.5 +/- 8.7, 117.5 +/- 9.1, and 120.0 +/- 11.5, respectively. Significantly increased rate of cells stained with fluorescent LPS was provoked by rhM-CSF at concentrations higher than 10(5) U/ml. Uptake indexes at concentrations of 10(5) and 10(6) U/ml were 115.2 +/- 6.4 and 118.0 +/- 4.3, respectively. These results indicate that M-CSF has a potency to stimulate DNA synthesis, phagocytic activity, and LPS uptake of mature Kupffer cells in vitro. This potency may be helpful to the enhancement or the recovery of the role of Kupffer cells, which is a part of the host defense mechanism, in diseased states.
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PMID:Effects of macrophage colony-stimulating factor on the proliferation and the function of Kupffer cells. 836 16

In this study we describe the time-dependent effects of a high dose (750 micrograms/ml/24 hr) continuous infusion of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on monocyte number, cytokine release, and superoxide anion production. Blood was taken from patients prior to rhGM-CSF infusion (day 0), and on days 1, 7, and 14 of infusion. The mean concentration of monocytes per ml of blood increased progressively from 4.3 x 10(5) on day 0 to 21 x 10(5) on day 14 of infusion. There was no significant change in the basal release of tumor necrosis factor alpha (TNF-alpha) or interleukin 1 beta (IL-1 beta) induced by rhGM-CSF. However, the lipopolysaccharide (LPS)-stimulated release of TNF-alpha by monocytes increased significantly on day 1 of infusion, and by day 14 had increased 8-fold. IL-1 beta release from LPS-stimulated monocytes increased slightly by day 7, and by almost 10-fold by day 14 of infusion. When maximally stimulated with phorbol dibutyrate, the monocytes demonstrated an increased (although not significant) capacity to produce superoxide anion on days 7 and 14 of infusion. No change in basal superoxide anion production was seen at any day of infusion. These GM-CSF-induced changes in stimulated cytokine and superoxide anion release could not be reproduced by treating monocytes with rhGM-CSF in vitro. In summary, a two week, high dose infusion of rhGM-CSF resulted in increases in circulating monocyte concentration, and in the stimulated release of TNF-alpha and IL-1 beta, and superoxide anion production from these monocytes. These primed monocytes could enhance the ability of neutropenic patients to fight infection.
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PMID:Effects of continuous high dose rhGM-CSF infusion on human monocyte activity. 839 50

Fibroblasts play an indirect augmenting effector role in the inflammatory response by releasing growth and differentiation factors and other inflammatory mediators after activation by inflammatory cytokines such as interleukin (IL)-1, but whether direct activation occurs by exogenous agents such as endotoxin (lipopolysaccharide, LPS) remains controversial. Using a number of primary human airways tissue-derived fibroblast lines, we demonstrate that in contrast to IL-1 alpha, LPS significantly induced gene expression and production of granulocyte/macrophage colony-stimulating factor (GM-CSF), IL-8, and IL-6 only in nasal but not bronchial or lung tissue-derived fibroblasts. Enhanced expression was dose- and time-dependent, and the minimal stimulatory dose was 10 ng LPS/ml. Polymyxin B entirely abrogated increased cytokine expression by LPS. Actinomycin D treatment largely inhibited expression, and LPS markedly increased an IL-6 gene promoter-driven luciferase reporter response in transfected nasal fibroblasts, suggesting enhanced expression may involve transcriptional regulation. Secondary protein or IL-1 synthesis requirement seemed unlikely since cycloheximide superinduced LPS-stimulated cytokine expression and anti-IL-1 alpha/beta antibodies failed to abrogate the response. Thus our data show that GM-CSF, IL-8, and IL-6 are directly inducible in nasal fibroblasts by LPS, and establish heterogeneous responsiveness to LPS by different fibroblast populations in the airways.
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PMID:Lipopolysaccharide induces expression of granulocyte/macrophage colony-stimulating factor, interleukin-8, and interleukin-6 in human nasal, but not lung, fibroblasts: evidence for heterogeneity within the respiratory tract. 839 62

In this study we evaluated the production of granulocyte/macrophage-colony stimulating factor (GM-CSF), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) by enriched bone marrow (BM) macrophages in 15 patients affected by myelodysplasia and 20 normal BM donors. The presence of GM-CSF, IL-6 and TNF-alpha in the culture supernatants of BM macrophages was detectable only after stimulation with lipopolysaccharide (LPS), whereas no differences were present in the amount of IL-6 and TNF-alpha between myelodysplastic patients and normal controls, GM-CSF production appeared eight-fold reduced in BM macrophage culture supernatants from myelodysplastic patients with respect to normal controls. After further experiments, we concluded that the impaired release of GM-CSF by BM macrophages could not be due to a different production kinetic in myelodysplastic patients. Moreover, the number of multipotent (CFU-GEMM), granulocyte/macrophage (CFU-GM) and erythroid (BFU-E) progenitors was significantly impaired in myelodysplastic patients. In conclusion, we demonstrated that the production of GM-CSF by purified adherent cells from MDS patients is markedly impaired in spite of the peripheral blood cytopenia. This selective defect in GM-CSF production, along with an intrinsic defect of haematopoietic progenitor cells, might contribute to the impairment of haematopoiesis always observed in myelodysplastic patients.
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PMID:Impairment of GM-CSF production in myelodysplastic syndromes. 839 22

The effects of the immunosuppressant mycophenolate mofetil (MPAM, RS-61443) on cytokine production at the single cell level were assessed using in vitro activated human mononuclear cells. Cytokine production was studied with UV microscopy of fixed and permeabilized cells stained with cytokine specific monoclonal antibodies (mAbs). The cytokines evaluated included interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-10 interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), TNF-beta, and granulocyte macrophage-colony stimulating factor (GM-CSF). MPAM exhibited a marked antiproliferative effect without cytotoxicity in all mononuclear cell cultures. Six to 24 hours after stimulation with the superantigen Staphylococcus aureus enterotoxin A (SEA), most cytokine production was unaffected by MPAM at therapeutic concentrations (10(-6) M), with the exception of GM-CSF. In contrast, by 48 h after antigen activation, MPAM significantly inhibited all studied cytokine production (p < 0.05). Cyclosporin A (CsA), used as a control at a concentration of 100 ng/ml, inhibited production of all studied cytokines, at all time points. Monokine production after lipopolysaccharide (LPS) stimulation was unaffected by MPAM. Similarly, the production of most of the cytokines studied after mitogen stimulation with phorbol ester (PMA) plus calcium ionophore (ionomycin) was not affected by MPAM, in comparison to CsA which demonstrated significant inhibition of all cytokines tested under these conditions. However, a late inhibitory effect on IL-3 production was seen by MPAM at 48 h after mitogenic stimulation. Further observations are required to explain the divergent results on cytokine production by MPAM in superantigen-activated and mitogen-activated human mononuclear cells.
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PMID:Effect of mycophenolate mofetil (RS-61443) on cytokine production: inhibition of superantigen-induced cytokines. 840 81

We studied the response of monocytes/macrophages (MO/MAC) to lipopolysaccharide (LPS) and interferon-gamma (IFN gamma) stimulation with respect to the expression of macrophage-specific products, i.e. macrophage-colony-stimulating factor (M-CSF), c-fms, c-sis, tissue factors, transforming growth factor-beta (TGF beta) and interleukin-8 (IL8) after in vitro infection with HIV. The expression of IL8 was strongly elevated in HIV-infected cells, peaking at 4 h after stimulation with LPS. At that time, the uninfected control showed only weak expression of IL8. Other products, e.g. tissue factor, c-fms, M-CSF and TGF beta were not modulated after stimulation. In contrast to IL8, the expression of c-cis was significantly lower in infected cells after stimulation with IFN gamma compared to uninfected control cells.
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PMID:Expression of macrophage products after in vitro infection of human monocytes/macrophages with HIV. 844 75

Resident pulmonary alveolar macrophages (PAM) play an important role in the maintenance of immunological homeostasis in the lung via downmodulation of local T cell responses in the steady state. The present study demonstrates that this pathway for T cell suppression is reversible via granulocyte/macrophage colony-stimulating factor (GM-CSF). Thus, freshly isolated PAM strongly inhibit mitogen-induced T cell proliferation, and pretreatment of the PAM with cytokine-rich lung-conditioned medium (LCM) generated by exposure of lung to bacterial lipopolysaccharide (LPS) abrogated this suppressive activity. LCM from lungs of normal and athymic nude mice exhibited identical activity. Moreover, the PAM-modulating activity of LCM was inhibited by blocking antibody specific for GM-CSF, and the activity of LCM could be reproduced by recombinant GM-CSF. This suggests that secretion of GM-CSF by mesenchymal cells and/or macrophages under stimulation from agents such as LPS provides a potential mechanism for upregulation of local T cell responsiveness during acute inflammation. In addition, experiments with a range of cytokines indicated that interleukin 4, transforming growth factor beta 1 and tumor necrosis factor alpha (TNF-alpha) exhibited weaker (but significant) modulatory effects on PAM, and (in the case of TNF-alpha) amplified the effects of GM-CSF.
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PMID:Inhibition of the immunosuppressive activity of resident pulmonary alveolar macrophages by granulocyte/macrophage colony-stimulating factor. 849 90

Murine peritoneal exudate macrophages (PEM) co-express granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage CSF (M-CSF) receptors, among others. Treatment of PEM with lipopolysaccharide (LPS) or tumor-promoting phorbol ester (12-O-tetradecanoylphorbol-13-acetate [TPA]) induces a rapid but transient loss of M-CSF receptors in PEM. GM-CSF receptors are not affected by this treatment. The loss of M-CSF receptors induced by LPS can be inhibited by neomycin and compound 48/80, two potent phospholipase C (PLC) inhibitors, but not by phospholipase A2, calpain, protein kinase C (PKC) or protease inhibitors. On the other hand, the loss of M-CSF receptors induced by TPA has been prevented by PKC inhibitors but not by PLC inhibitors. PLC inhibitors also prevent LPS-suppressed receptor-mediated internalization of radiolabeled recombinant human (rh) M-CSF by macrophages. Similar prevention of LPS-induced M-CSF receptor downregulation was observed in human monocytes that had been pretreated with PLC inhibitors. Our results show that 1) TPA-induced M-CSF receptor loss is strictly dependent on PKC activation; 2) PLC activation alone also leads to downregulation of M-CSF receptors; and 3) LPS-induced M-CSF receptor downregulation in PEM is mediated primarily through a PLC-dependent pathway. Our data also imply that the expression of M-CSF but not GM-CSF receptors is linked to an important, yet unknown, PLC-sensitive component(s) whose hydrolysis may lead to downregulation of M-CSF receptors.
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PMID:Downregulation of M-CSF receptors by lipopolysaccharide in murine peritoneal exudate macrophages is mediated through a phospholipase C dependent pathway. 851 62

Human cytomegalovirus (CMV) infection is often associated with myelosuppression and acute inflammatory reaction in immunocompromised patients. We have previously documented that CMV exposure of bone marrow (BM) stromal cells reduces the capacity of these cells to support hematopoiesis because of a decreased production of colony-stimulating factors. This study examines the potential role of CMV on constitutive and lipopolysaccharide (LPS)-stimulated production of cytokines involved in inflammatory reaction, interleukin-6 (IL-6) and leukemia inhibitory factor (LIF) by BM stromal cells. The release of IL-6 was already detectable 2 hours post CMV-infection (2.5-fold increase in production) and the cumulative production of IL-6 after 5 days of infection was 23 +/- 1.2 ng/mL (ninefold increase in production). CMV was also able to induce a time-dependent production of LIF that was maximal 8 hours after CMV infection (2.5-fold increase in production). Concomitantly, there was no detectable release of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage CSF (GM-CSF) by CMV-infected stromal cells. The similar IL-6 and LIF production in the presence of polymyxin B ruled out the possibility that this increase could be caused by contamination of the viral stock by endotoxin. In addition, ultraviolet-inactivated virus behaved similarly to live virus and caused the release of IL-6 and LIF. However, heat-inactivated CMV was unable to induce IL-6 and LIF secretion by BM stromal cells. The production of IL-6 and LIF was also evaluated after stimulation by LPS. After 5 days of CMV exposure, the LPS-stimulated production of IL-6 and LIF was significantly lower than uninfected controls. This LPS-induced release of cytokine production was found to be dependent of viral replication. The experiments have shown that CMV is a potent inducer of IL-6 and LIF with differential effect on constitutive and LPS-stimulated cytokine production by stromal cells; we suggest that CMV induction of IL-6 and LIF during the first hours of infection could play a role in CMV-induced inflammatory reaction. Moreover, our results show that human CMV can disturb the balanced cytokine network involved in the regulation of hematopoiesis.
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PMID:Human cytomegalovirus increases constitutive production of interleukin-6 and leukemia inhibitory factor by bone marrow stromal cells. 854 77


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