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PubMed2005

Interleukin-8 response in cells from the human urinary tract induced by lipopolysaccharides of Proteus mirabilis O3 and O18.

PURPOSE: Proteus mirabilis is a common pathogen associated mainly with complicated urinary tract infections and sometimes with septicemia. There is great serological diversity of the microorganism. While P. mirabilis O3 is commonly found in patients with infections, the serotype O18 rarely occurs. The O18 lipopolysaccharide contains a phosphocholine substitute, which makes it unique among Proteus strains. To explain different clinical significance of the strains we evaluated the biological activity of the lipopolysaccharides of P. mirabilis O3 and O18, as measured by interleukin-8 (IL-8) production. MATERIALS AND METHODS: Three cell lines were used, namely uroepithelial cells, renal epithelial cells and monocytes. IL-8 production was determined on the protein and mRNA levels using enzyme-linked immunosorbent assay and real-time polymerase chain reaction, respectively, and CD14 expression on the cell surface was studied using flow cytometry. RESULTS: Uroepithelial cells and monocytes reacted to lipopolysaccharides by higher IL-8 production compared with renal epithelial cells. Cell specific IL-8 response corresponded to the cell expression of CD14. Renal epithelial cells produced more IL-8 after stimulation with the phosphocholine rich lipopolysaccharide O18, although adding phosphocholine alone did not induce or increase IL-8 production. CONCLUSIONS: Our data suggest that different cells within the human urinary tract have different roles during urinary tract infection. The biological activity and pathogenicity of P. mirabilis lipopolysaccharides might be determined by their specific chemical structure.

Cell Line↗

PubMedDate not supplied

Lipopolysaccharide in combination with serum potentiates the stimulated activity of phospholipase D in human neutrophils via CD14.

The addition of fMet-Leu-Phe or phorbol 12-myristate 13-acetate to human neutrophils stimulates phospholipase D activity as evidenced by the release of phosphatidic acid and the generation of diacylglycerol, and in the presence of ethanol the formation of phosphatidyl ethanol. The activation of phospholipase D by either the chemotactic factor or active phorbol ester is inhibited by the tyrosine kinase inhibitor erbstatin. The fMet-Leu-Phe-induced stimulation of this enzyme is greatly potentiated in cells which have been preincubated with low concentrations of lipopolysaccharide and serum. The presence of serum is essential for the potentiation by low concentrations of lipopolysaccharide. Moreover, the monoclonal antibody MY4(IgG2b) against CD14 inhibits the potentiation by the low concentration of lipopolysaccharide. These data suggest three important points. First, a tyrosine kinase step is necessary for the activation of phospholipase D. This suggests that the phospholipase D enzyme needs to be phosphorylated on tyrosine residues to be activated. Second, low concentrations of lipopolysaccharide, in the presence of serum, can potentiate the stimulated activity of this enzyme. Third, the priming action of the lipopolysaccharide-serum complex is mediated by CD14.

Adult↗

PubMed1994

Reduced tumor necrosis factor alpha production in lipopolysaccharide-treated whole blood from patients in the intensive care unit.

OBJECTIVE: To determine the cytokine response to lipopolysaccharide in patients in the intensive care unit. PATIENTS: Patients in a mixed medical/surgical intensive care unit with fever and a de novo clinical dysfunction of at least one organ system. METHODS: Whole blood from patients and from laboratory controls was stimulated with 8 ng/mL of lipopolysaccharide (Escherichia coli 0111:B4) at 37 degrees C, and tumor necrosis factor alpha (TNF-alpha) was measured using enzyme linked immunosorbent assay at 4, 8, and 24 hours. The same subjects' purified monocytes were cultured with 8 ng/mL of lipopolysaccharide in the presence of autologous or pooled control plasma or cocultured with purified autologous polymorphonuclear leukocytes at a polymorphonuclear leukocyte-monocyte ratio of 10:1, and TNF-alpha was measured at 24 hours using the enzyme linked immunosorbent assay. RESULTS: We detected high (n = 5) and low (n = 5) TNF-alpha responders in whole blood producing a mean (+/- SEM) of 27.2 +/- 6.3 pg/mL per 1000 monocytes vs 0.0 +/- 2.4 pg/mL per 1000 monocytes, respectively (controls, 58.0 +/- 13.0 pg/mL per 1000 monocytes). The kinetics of TNF-alpha production in both groups were comparable. Purified monocytes from both groups of patients cultured with lipopolysaccharide alone produced equivalent TNF-alpha values (42.4 +/- 10.5 vs 40.8 +/- 12.5 pg/mL per 1000 monocytes). Assayable TNF-alpha was not different with autologous vs control serum but was markedly diminished by the presence of polymorphonuclear leukocytes in patients as well as in controls; the two groups of patients did not differ in this polymorphonuclear leukocyte effect. CONCLUSION: Lipopolysaccharide stimulation of monocytes in the whole blood results in marked variation of TNF-alpha production. This phenomenon may account for the variable septic response to infection in patients in the intensive care unit.

Adult↗

PubMed2002

Pseudomonas aeruginosa strains with lipopolysaccharide defects exhibit reduced intracellular viability after invasion of corneal epithelial cells.

Pseudomonas aeruginosa is a leading cause of infectious keratitis. Many ocular isolates of this bacterium invade corneal epithelial cells in vitro and in vivo. Antibiotic survival assays have shown that a complete core lipopolysaccharide is required for full epithelial invasion by P. aeruginosa. In this study, we show that P. aeruginosa mutants with defects in their lipopolysaccharide core and O antigen exhibited reduced viability after internalization by corneal epithelial cells. Restoration of lipopolysaccharide core and O antigen expression by complementation with the plasmid pLPS1 restored intracellular survival. P. aeruginosa strains with a complete lipopolysaccharide survived and replicated within the cells. The data suggest that lipopolysaccharide is involved in the intracellular survival and/or replication of P. aeruginosa, indicating an additional mechanism by which this important virulence factor may contribute to the pathogenesis of corneal infection.

Animals↗

PubMed1990

Participation of interleukin-1 and tumor necrosis factor in the responses of the sympathetic nervous system during lipopolysaccharide-induced fever.

The regional sympathetic responses during fevers induced by an exogenous pyrogen, lipopolysaccharide, and by two endogenous pyrogens, interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha), were compared in urethane-anesthetized rabbits. Rectal temperature (Tre), ear skin temperature (Tear) as an index for cutaneous sympathetic activity, renal sympathetic nerve activity (RSNA) representing visceral efferents, arterial blood pressure, and heart rate were recorded during fever caused by intravenous injections of each of the three pyrogens. Lipopolysaccharide (1 micrograms/kg i.v.) caused prolonged fever of more than 3 h duration with a tendency towards a biphasic course of temperature, whereas fevers induced by IL-1 beta (1 microgram/kg i.v.) and TNF-alpha (10 micrograms/kg i.v.) were monophasic with a maximum between the 45th and 60th min. Each of the three pyrogens typically induced a decrease in Tear, indicative of cutaneous sympathetic activation, and simultaneous inhibition of RSNA during the first phase of rising Tre. RSNA tended to increase again approximately to its control level when the maximum Tre had been attained after the injection of each pyrogen. When the second rising phase of lipopolysaccharide fever started, Tear decreased once more, but RSNA remained at its control level. Taken together with the enhancement of IL-1 and TNF production during lipopolysaccharide-induced fever, the present results suggest the participation of these endogenous pyrogens in the responses of the sympathetic nervous system during the early phase of the lipopolysaccharide induced fever.

Animals↗

PubMed1986

Cross-reactivity of monoclonal antibodies against lipopolysaccharides of gram-negative bacteria.

Monoclonal antibodies were produced against Escherichia coli O111, Escherichia coli J5, and the rough (R) mutant of Salmonella typhimurium M206, and tested by enzyme-linked immunosorbent assay against lipopolysaccharides of several gram-negative strains. The monoclonal antibodies were also identified with an immunoblotting assay. Anti-Escherichia coli O111 monoclonal antibodies reacted only with homologous O antigens. Anti-J5 monoclonal antibodies cross-reacted with core lipopolysaccharide, especially with Rc lipopolysaccharide. IgM anti-J5 monoclonal antibodies showed more extensive cross-reactivity than IgG3 monoclonal antibodies. Anti-Re monoclonal antibodies cross-reacted weakly with all rough lipopolysaccharide tested. Thus, the varying specificity of these monoclonal antibodies seems to indicate that the core regions in the lipopolysaccharides of various gram-negative bacteria are not similar.

Animals↗

PubMed2002

Effects of nitric oxide synthase inhibitors on the febrile response to muramyl dipeptide and lipopolysaccharide in rats.

We have administered aminoguanidine, a relatively specific inhibitor of inducible nitric oxide synthase, and N-nitro-L-arginine methyl ester (L-NAME), an unspecific nitric oxide synthase inhibitor, to rats made febrile with the gram-positive pyrogen, muramyl dipeptide and gram-negative pyrogen, lipopolysaccharide. Sprague-Dawley rats, housed individually at approximately 25 degrees C with a 12:12 h light:dark cycle (lights on 0700 hours), were injected (at 0900 hours) intraperitoneally with 50 mg/kg aminoguanidine, 25 mg/kg or 50 mg/kg L-NAME, and intramuscularly with 500 microg/kg muramyl dipeptide or 100 microg/kg lipopolysaccharide. Pyrogen injections were spaced at least 14 days apart. Body temperature was measured throughout the study in unrestrained animals using radio-telemetry. Neither muramyl dipeptide nor lipopolysaccharide-induced fevers were affected by aminoguanidine. However, L-NAME administration inhibited muramyl dipeptide and lipopolysaccharide-induced fevers, but only for the 1st 2-4 h of the fevers (two-way ANOVA, P<0.05). After the initial inhibition, lipopolysaccharide fevers developed normally. Therefore, constitutively expressed nitric oxide synthase appears to be involved in the initial phases of fever genesis of gram-negative and gram-positive fevers in rats. On the other hand, inducible nitric oxide synthase appears not to play a role in these fevers.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed1999

Lipopolysaccharide of Escherichia coli, polyamines, and acetic acid stimulate cell proliferation in intestinal epithelial cells.

Our aim was to examine whether lipopolysaccharide of Escherichia coli, polyamines of dietetic and/or bacterial origin, and products of the bacterial metabolism influence cell proliferation in epithelial cells from the colon and small intestine. Lipopolysaccharide of Escherichia coli 0111:B4 was incubated with cultures from human colonic mucosa. The mitoses were arrested with Vincristine and the total number of metaphases per crypt was counted. In addition, lipopolysaccharide was incubated with a human colonic epithelial cell line from adenocarcinoma (LS-123 cells) and with a nontransformed small intestinal cell line from germ-free rats (IEC-6 cells) for 24 h. In the last 4 h, the cells were labeled with tritiated thymidine. The cells were incubated with putrescine, cadaverine, and spermidine at 10(-11)-10(-3) M and with acetic acid (10(-5)-10(-1) M), acetaldehyde (10(-10)-10(-4) M) and ammonium chloride (1-20 mM). Lipopolysaccharide of Escherichia coli increased the number of arrested metaphases in human colonic crypts and DNA synthesis in L-123 and IEC-6 cells (P < 0.001). All polyamines increased DNA synthesis in the colonic and small intestinal cell lines, the effects being more marked for putrescine (P < 0.001). The higher concentrations of acetic acid increased DNA synthesis in both epithelial cell lines (P < 0.001). Acetaldehyde slightly decreased DNA synthesis in LS-123 cells at cytotoxic concentrations. Ammonium chloride did not significantly affect DNA synthesis. The final concentration of nonionized ammonia was less than 3%. It is concluded that lipopolysaccharides of Escherichia coli and intraluminal factors derived from microorganisms increase cell proliferation in human colonic crypts and intestinal epithelial cell lines.

Acetaldehyde↗

PubMed1986

Interferon: a mediator of indoleamine 2,3-dioxygenase induction by lipopolysaccharide, poly(I) X poly(C), and pokeweed mitogen in mouse lung.

When C3H/He mice were treated with lipopolysaccharide, poly(I) X poly(C), or pokeweed mitogen, the serum interferon titer increased almost instantaneously (100-2000 units/ml), and then the pulmonary indoleamine 2,3-dioxygenase was induced 50- to 140-fold. The peaks corresponding to interferon induction always preceded (approximately 24 h) those corresponding to dioxygenase induction. In C3H/HeJ (lipopolysaccharide-nonresponder) mice, however, lipopolysaccharide was totally inert in induction of both interferon and dioxygenase, although treatment with poly(I) X poly(C) and pokeweed mitogen led to a remarkable increase in the serum interferon titer and the enzyme activity. When lymphocytes of C3H/HeJ mice were inactivated by X irradiation and then reconstituted by the transfer of spleen cells from C3H/He mice, both enzyme and interferon from C3H/HeJ mice thus treated were induced almost normally after the lipopolysaccharide treatment. In addition, murine interferon alpha/beta, which was injected intravenously in C3H/He or C3H/HeJ mice, almost instantaneously and dose-dependently induced the pulmonary enzyme, and at a dose of 10(5) units per mouse the enzyme activity was enhanced 20- to 26-fold in these two strains of mice. These results suggest that interferon, which is generated by the interaction of lymphocytes with lipopolysaccharide, poly(I) X poly(C), or pokeweed mitogen, is a mediator of indoleamine 2,3-dioxygenase induction in the mouse lung by these agents.

Animals↗

PubMed1991

Inhibition of bovine gingival laminin receptor by bacterial lipopolysaccharide.

A laminin receptor was isolated from bovine gingival epithelial-cell membrane. After solubilization with octylglucoside, the receptor was subjected to affinity chromatography on laminin-coupled Sepharose and eluted with cation-free EDTA buffer yielding on SDS-PAGE a 67 kDa protein band. After radioiodination, the protein was incorporated into liposomes which displayed specific affinity towards laminin-coated surfaces, as well as to tooth cementum. The binding of receptor protein to cementum was inhibited by lipopolysaccharide from Bacteroides gingivalis. Preincubation of cementum with the lipopolysaccharide decreased the binding of the liposomal laminin-receptor preparation by 35.8%, while a 59.2% decrease in binding occurred when the lipopolysaccharide was preincubated with the receptor, suggesting that the lipopolysaccharide interfered with the laminin binding site on the receptor. The results demonstrate the existence of a specific gingival cell-surface laminin receptor, show that it is capable of binding to cementum, and provide evidence for the disruption of this process by bacterial lipopolysaccharide. This mechanism may account for the loss of gingival attachment in the pathogenesis of periodontal disease.

Affinity Labels↗

PubMed1978

The binding of lipopolysaccharide from Escherichia coli to mammalian cell membranes and its effect on liposomes.

The kinetics of the absorption of 32P- or 14C-labelled lipopolysaccharide from Escherichia coli NCTC 8623, serotype 0 125, chemotype XII, to erythrocytes, leukocytes, peritoneal macrophages and peritoneal lymphocytes was examined. Under variable conditions maximal levels of binding were found due to saturation of receptor sites on the cell membrane or steric hindrance by bound lipopolysaccharide. During adsorption slight leakage of haemoglobin was found but complete lysis of erythrocytes was ruled out after noting the effect of lipopolysaccharide on artificial lipid bilayers. The affinit of lipopolysaccharide to cell membranes revealed a consistent pattern of cyclic fluctuation between adsorption and desorption. A model was proposed to explain this cyclic fluctuation in binding based on membrane reorganization. It was significant that the cycle of lipopolysaccharide adsorption-desorption proceeded to completion even if the process was interrupted. The indication was that, once triggered, membrane reorganization occurred independently without influence from the test environment.

Animals↗

PubMed1989

Changes in neutral amino acid transport activity in myeloid leukemia cells differentiated by lipopolysaccharide.

M1 cells derived from mouse myeloid leukemia have been reported to differentiate to macrophage-like cells upon treatment with substances such as lipopolysaccharide. Previously we found that in mouse peritoneal macrophages most of the neutral amino acids were taken up through a unique Na+-independent system. In this paper we have investigated the neutral amino acid transport in M1 cells and in those treated with lipopolysaccharide. In M1 cells serine, alanine and proline were taken up mainly by Na+-dependent transport systems, and leucine was largely transported by a Na+-independent system. By treating the cells with lipopolysaccharide, the activities of the Na+-dependent systems markedly decreased, whereas the activity of the Na+-independent system was little affected. The amino acid concentrations in the cells and the culture medium were measured. As a whole, the intracellular to extracellular distribution ratios for neutral amino acids that are preferred substrates for Na+-dependent systems were decreased on lipopolysaccharide treatment, whereas those for amino acids that are mainly transported by a Na+-independent system were slightly increased. From these results we conclude that M1 cells treated with lipopolysaccharide tend to differentiate to macrophage-like cells with respect to the neutral amino acid transport.

Amino Acid Transport Systems↗

PubMed1991

A comment on the preparation of liposomes from and on the beta in equilibrium alpha acyl chain melting behaviour of rough mutant lipopolysaccharide.

We would like to comment on the investigations of Vaara, M., Plachy, W.Z. and Nikaido, H. (Vaara, M. et al. (1990) Biochim. Biophys. Acta 1024, 152-158) on the partitioning of hydrophobic probes in lipopolysaccharide bilayers. These authors reported that they did not succeed in preparing closed vesicles (liposomes) from rough mutant lipopolysaccharide. We describe the conditions under which lipopolysaccharide liposomes are formed most readily. We, furthermore, summarize data which strongly support the existence of thermotropic phase transitions of lipopolysaccharides (with transition temperatures lying in the range of 30-36 degrees C) contradictory to Vaara et al. who argue that such transitions are artefacts. Exemplary measurements of the beta in equilibrium alpha acyl chain melting for lipopolysaccharide from Escherichia coli deep rough mutant (strain F515) as compared to synthetic and natural phospholipids are presented using fluorescence spectroscopy, Fourier-transform infrared spectroscopy and differential scanning calorimetry. These results unequivocally prove the necessity to perform experiments at 37 degrees C for a determination of the outer membrane permeability under physiological conditions.

Hot Temperature↗

PubMed1995

Effect of Escherichia coli lipopolysaccharide on surfactant secretion in primary cultures of rat type II pneumocytes.

The purpose of this study is to evaluate the effect of the Escherichia coli lipopolysaccharide on the secretion of phosphatidylcholine, the principal component of pulmonary surfactant, in primary cultures of rat alveolar type II pneumocytes. Lipopolysaccharide stimulated phosphatidylcholine secretion in a time- and dose-dependent manner. At a concentration of 200 micrograms/ml, lipopolysaccharide stimulated the release of phosphatidylcholine 4-fold over the basal secretory rate, and the concentration producing half the maximal response was 20 micrograms/ml. The stimulatory effect of lipopolysaccharide on phosphatidylcholine secretion was additive to that of the protein kinase C activator TPA, which is a potent stimulator of surfactant secretion. Lipopolysaccharide did not activate protein kinase C, which suggests that stimulation of phosphatidylcholine secretion by the endotoxin was through a mechanism independent of protein kinase C activation.

Animals↗

PubMed1989

Sensitization of alveolar macrophages to lipopolysaccharide-induced prostaglandin synthesis by exogenous prostaglandins.

Rabbit alveolar macrophages were found to produce extraordinary amounts of prostaglandin E2 and F2 alpha with the stimulation of lipopolysaccharide or lipid A. Exogenous prostaglandin E2 greatly enhanced the lipopolysaccharide action on rabbit alveolar macrophages for the induction of prostaglandin F2 alpha release (3-5 fold), while prostaglandin E2 alone did not cause any effect. The enhancement expressed was especially strong when prostaglandin E2 was administered to the cells simultaneously with lipopolysaccharide. The effect of prostaglandin E2 was observed neither with a nonstimulating dose of lipopolysaccharide nor with a stimulating dose of zymosan. This phenomenon was even more pronounced when prostaglandin I2 was used instead of prostaglandin E2, while no sensitization was demonstrated by prostaglandin F2 alpha. These observations suggest that prostaglandins can modulate the activation of the cyclooxygenase pathway of arachidonate metabolism in the activated macrophages by lipopolysaccharide.

Animals↗

PubMed1996

Interleukin-1 receptor antagonist does not reverse lipopolysaccharide-induced inhibition of water intake in rat.

The involvement of interleukin-1 in antidipsogenic effects induced by intraperitoneal (i.p.) administration of lipopolysaccharide (0.32, 0.64 and 0.96 mg/kg) in 24-h water-deprived rats, was evaluated by injection of human interleukin-1 receptor antagonist (10, 25 and 50 micrograms/rat) into the lateral cerebral ventricle (i.c.v.). The effects of either lipopolysacharide or human interleukin-1 receptor antagonist treatment on rectal temperature of 24-h water-deprived rats, were examined. Our date show that human interleukin-1 receptor antagonist administration is able to reverse, dose dependently, fever, but not lipopolysaccharide inhibition of thirst. The reduction of pyrogenic, but not of antidipsogenic, effects of lipopolysaccharide following human interleukin-1 receptor antagonist administration suggests that lipopolysaccharide inhibition of thirst is not dependent on interleukin-1 induced fever and that interleukin-1 is not a direct mediator implicated in inhibition of water intake provoked by peripheral injection of lipopolysaccharide.

Animals↗

PubMed1990

Interactions between Salmonella typhimurium lipopolysaccharide and the antimicrobial peptide, magainin 2 amide.

Effects of magainin 2 amide on the phase behavior of Salmonella typhimurium lipopolysaccharide were characterized by FT-IR spectroscopy. This antimicrobial cationic peptide disorders the lipopolysaccharide at molecular ratios of lipopolysaccharide to magainin greater than 4, and can induce a temperature-dependent structural reorientation. The nature of the five phosphate groups of lipopolysaccharide was determined by 31P NMR spectroscopy. At pH 7.4, the net charge on the phosphates is -7. Lipopolysaccharide undoubtedly plays an important role in modulating the interactions of magainin with the gram-negative cell envelope and may act as a molecular sponge to protect the plasma membrane.

Animals↗

PubMed1990

Pentoxifylline inhibits lipopolysaccharide-induced serum tumor necrosis factor and mortality.

Tumor necrosis factor, a mononuclear phagocyte-derived peptide produced in response to lipopolysaccharide, has been shown to mediate certain aspects of septic shock and multiple organ failure resulting from gram-negative septicemia. In the present investigation, pretreatment of animals with pentoxifylline inhibited lipopolysaccharide-induced serum tumor necrosis factor in a dose-dependent fashion. Pentoxifylline prevented the sequestration of neutrophils seen in animals given intravenous lipopolysaccharide. Furthermore, pentoxifylline protected animals from the lethal effects of an intravenous challenge with lipopolysaccharide. These data indicate that pentoxifylline inhibits lipopolysaccharide-induced tumor necrosis factor and may be an effective agent in mitigating the lethal consequences of sepsis and other disease processes mediated by this cytokine.

Animals↗