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)

In vitro, nitric oxide (NO) decreases leukocyte adhesion to endothelium by attenuating endothelial adhesion molecule expression. In vivo, lipopolysaccharide-induced leukocyte rolling and adhesion was greater in inducible NO synthase (iNOS)-/- mice than in wild-type mice. The objective of this study was to assess E- and P-selectin expression in the microvasculature of iNOS-/- and wild-type mice subjected to acute peritonitis by cecal ligation and perforation (CLP). E- and P-selectin expression were increased in various organs within the peritoneum of wild-type animals after CLP. This CLP-induced upregulation of E- and P-selectin was substantially reduced in iNOS-/- mice. Tissue myeloperoxidase (MPO) activity was increased to a greater extent in the gut of wild-type than in iNOS-/- mice subjected to CLP. In the lung, the reduced expression of E-selectin in iNOS-/- mice was not associated with a decrease in MPO. Our findings indicate that NO derived from iNOS plays an important role in sepsis-induced increase in selectin expression in the systemic and pulmonary circulation. However, in iNOS-/- mice, sepsis-induced leukocyte accumulation is affected in the gut but not in the lungs.
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PMID:Endothelial E- and P-selectin expression in iNOS- deficient mice exposed to polymicrobial sepsis. 1120 53

Stimulation of endothelial cells by various inflammatory mediators leads to release of Weibel--Palade bodies and therefore to exocytosis of both P-selectin (adhesion receptor for leukocytes) and von Willebrand factor (vWf) (platelet ligand). The potential role of vWf in leukocyte recruitment was investigated with the use of vWf-deficient mice. We report a strong reduction of leukocyte rolling in venules of vWf-deficient mice. Similarly, vWf deficiency led to a decrease in neutrophil recruitment in a cytokine-induced meningitis model as well as in early skin wounds. In all instances with an antibody that preferentially recognizes plasma membrane P-selectin, we observed a dramatic reduction in P-selectin expression at the cell surface of vWf-deficient endothelium. With confocal microscopy, we found that the typical rodlike shape of the Weibel--Palade body is missing in vWf -/- endothelial cells and that part of the P-selectin content in the vWf -/- cells colocalized with LAMP-1, a lysosomal marker. However, intracellular P-selectin levels were similar in tumor necrosis factor alpha- and lipopolysaccharide-activated cells of both genotypes. We conclude that the absence of vWf, as found in severe von Willebrand disease, leads to a defect in Weibel--Palade body formation. This defect results in decreased P-selectin translocation to the cell surface and reduced leukocyte recruitment in early phases of inflammation.
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PMID:Defect in regulated secretion of P-selectin affects leukocyte recruitment in von Willebrand factor-deficient mice. 1127 31

In this study, self-organizing map (SOM) gene cluster techniques are applied to the analysis of cDNA microarray analysis of gene expression changes occurring in the early stages of genitourinary inflammation. We determined the time course of lipopolysaccharide (LPS)-induced gene expression in experimental cystitis. Mice were euthanized 0.5, 1, 4, and 24 h after LPS instillation into the urinary bladder, and gene expression was determined using four replicate Atlas mouse cDNA expression arrays containing 588 known genes at each time point. SOM gene cluster analysis, performed without preconditions, identified functionally significant gene clusters based on the kinetics of change in gene expression. Genes were classified as follows: 1) expressed at time 0; 2) early genes (peak expression between 0.5 and 1 h); and 3) late genes (peak expression between 4 and 24 h). One gene cluster maintained a constant level of expression during the entire time period studied. In contrast, LPS treatment downregulated the expression of some genes expressed at time 0, in a cluster including transcription factors, protooncogenes, apoptosis-related proteins (cysteine protease), intracellular kinases, and growth factors. Gene upregulation in response to LPS was observed as early as 0.5 h in a cluster including the interleukin-6 (IL-6) receptor, alpha- and beta-nerve growth factor (alpha- and beta-NGF), vascular endothelial growth factor receptor-1 (VEGF R1), C-C chemokine receptor, and P-selectin. Another tight cluster of genes with marked expression at 1 h after LPS and insignificant expression at all other time points studied included the protooncogenes c-Fos, Fos-B, Fra-2, Jun-B, Jun-D, and Egr-1. Almost all interleukin genes were upregulated as early as 1 h after stimulation with LPS. Nuclear factor-kappaB (NF-kappaB) pathway genes collected in a single cluster with a peak expression 4 h after LPS stimulation. In contrast, most of the interleukin receptors and chemokine receptors presented a late peak of expression 24 h after LPS coinciding with the peak of neutrophil infiltration into the bladder wall. Selected cDNA microarray observations were confirmed by RNase protection assay. In conclusion, the cDNA array experimental approach provided a global profile of gene expression changes in bladder tissue after stimulation with LPS. SOM techniques identified functionally significant gene clusters, providing a powerful technical basis for future analysis of mechanisms of bladder inflammation.
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PMID:Time course of LPS-induced gene expression in a mouse model of genitourinary inflammation. 1128 68

In an attempt to explore a novel therapeutic approach, a new synthetic sulfatide derivative (SKK60037) was evaluated in an acute rat model of P-selectin and leukocyte-dependent thrombotic glomerulonephritis (TG). In vitro, SKK60037 inhibits the function of P- and L-selectin more effectively than sialyl Lewis X (sLe(x)), a well-established selectin blocker. TG was induced by the intravenous administration of nephrotoxic globulin (NTG) to rats pretreated with a subclinical dose of lipopolysaccharide. In this model, platelet accumulation was remarkable within 10 minutes after induction of disease, followed by the infiltration of leukocytes, mainly neutrophils and macrophages. Thrombus formation and fibrinogen deposition in the glomeruli were observed within 1 hour, and they proceeded until 6 hours. P-selectin was highly expressed in glomeruli, whereas E-selectin and L-selectin ligands were not detected. We tested the effects of SKK60037 in this model in comparison with sLe(x) and antirat P-selectin monoclonal antibody (ARP2-4). SKK60037 blocked platelet accumulation in glomerular capillaries at 10 minutes after NTG injection. At 6 hours, leukocyte infiltration and thrombosis were significantly suppressed. Protective effects of SKK60037 were similar to those of ARP2-4, whereas sLe(x) showed minimum effect. The superior effects and more favorable characteristics of SKK60037 to sLe(x) suggest the potential of SKK60037 for clinical application.
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PMID:Effects of a new synthetic selectin blocker in an acute rat thrombotic glomerulonephritis. 1147 51

Expression of E-selectin on activated endothelium is a critical initial step that leads to extravasation of leucocytes during inflammation, yet E-selectin is largely uncharacterized in several animal species including the horse. We have sequenced and compared E-selectin genes derived from activated cultures of purified equine (horse), cervid (black-tailed deer) and ovine (sheep) pulmonary artery endothelial cells (ECs). Phylogenetic and amino acid sequence comparisons indicate that bovine, cervid and ovine E-selectin are similar, whereas human and equine E-selectin are more closely related to each other than to the ruminant molecules. Human E- and P-selectin-specific monoclonal antibodies that also recognize equine E-selectin were identified and used to characterize its expression. Expression of E-selectin was more readily induced by lipopolysaccharide treatment in equine ECs than in human ECs and supported adhesion and activation of neutrophils, consistent with the extreme sensitivity of horses to endotoxaemia and septic shock.
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PMID:Characterization of equine E-selectin. 1152 41

NF-kappaB/Rel transcription factors have been implicated in the differentiation of monocytes to either dendritic cells (DCs) or macrophages, as well as in the maturation of DCs from antigen-processing to antigen-presenting cells. Recent studies of the expression pattern of Rel proteins and their inhibitors (IkappaBs) suggest that their regulation during this differentiation process is transcriptional. To investigate differential gene expression between macrophages and DCs, we used commercially available gene microarrays (GEArray KIT), which included four of the NF-kappaB/Rel family genes (p50/p105, p52/p100, RelB, and c-rel) and 32 additional genes either in the NF-kappaB signal transduction pathway or under transcriptional control of NF-kappaB/Rel factors. To generate macrophages and DCs, human adherent peripheral blood monocytes were cultured with M-CSF or GM-CSF + IL-4 respectively for up to 8 days. DCs (and in some experiments, macrophages) were treated with lipopolysaccharide (LPS) for the last 48 h of culture to induce maturation. Cells were harvested after 7 days, cDNA was prepared and radiolabeled with alpha-(32)P-dCTP, then hybridized to gene arrays containing specific gene probes. beta-actin and GAPDH or PUC18 oligonucleotides served as positive or negative controls, respectively. The expression of all four NF-kappaB/Rel family genes examined was significantly upregulated in maturing DCs compared to macrophages. The strongest difference was observed for c-rel. RT-PCR determinations of c-rel, RelB, and p105 mRNAs confirmed these observations. Among the 32 NF-kappaB/Rel pathway genes, 14 were upregulated in mature DCs compared to macrophages. These genes were IkappaBalpha, IKK-beta, NIK, ICAM-1, P-selectin, E-selectin, TNF-alpha, TNFR2, TNFAIP3, IL-1alpha, IL-1R1, IL-1R2, IRAK, and TANK. By contrast, only mcp-1 (monocyte chemotactic protein 1) was upregulated in macrophages compared to DCs. NF-kappaB pathway genes upregulated in DCs compared to macrophages were constitutively expressed in monocytes then selectively downregulated during macrophage but not DC differentiation. LPS did not induce expression of most of these genes in macrophages but LPS did induce upregulation of IL-8 in mature macrophages. We conclude that NF-kappaB/Rel family genes, especially c-rel, are selectively expressed during differentiation of monocytes towards DCs. Moreover, this differential expression is associated both with activation of different NF-kappaB signal transduction pathways in DCs and macrophages and with expression of a unique subset of genes in DCs that are transcriptionally targeted by NF-kappaB/Rel factors. The results illustrate the ability of the NF-kappaB pathway to respond to differentiation stimuli by activating in a cell-specific manner unique signalling pathways and subsets of NF-kappaB target genes.
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PMID:Expression of different NF-kappaB pathway genes in dendritic cells (DCs) or macrophages assessed by gene expression profiling. 1157 45

It is well established that constitutive production of nitric oxide is central to numerous processes in the microvasculature, including controlling the trafficking of inflammatory leucocytes. However, during many inflammatory responses induction of inducible nitric oxide synthase (iNOS) increases nitric oxide production. The role of iNOS-derived nitric oxide in modulating leucocyte recruitment is less well understood, although recent studies using iNOS-deficient mice have begun to examine this issue. This article describes much of the work that implicates iNOS as having a role in controlling leucocyte recruitment, including the intravital microscopy studies which revealed that iNOS-deficient mice have elevated leucocyte-endothelial cell interactions during endotoxaemia. Furthermore in additional studies, we compared expression of endothelial adhesion molecules in wild-type and iNOS-deficient mice, under conditions in which iNOS was expressed. Adhesion molecule expression was measured using an in vivo dual radiolabel immunoassay. To induce iNOS, mice were treated with either 1 or 50 microg of bacterial lipopolysaccharide (LPS), and 4 h later expression of P-selectin, E-selectin and vascular cell adhesion molecule-1 was determined in eight different tissues. In nearly all cases, adhesion molecule expression did not differ between the two types of mice, either in the absence of an inflammatory stimulus, or following LPS treatment. These findings indicate that iNOS does not regulate expression of endothelial adhesion molecules either under basal conditions, or during the endotoxaemic response. This further suggests that alterations in leucocyte function may mediate the modulating effect of iNOS on leucocyte recruitment.
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PMID:Inducible nitric oxide synthase (iNOS) and regulation of leucocyte/endothelial cell interactions: studies in iNOS-deficient mice. 1167 34

Although about 80% of tissue factor (TF) extracellular domain antigen present in lipopolysaccharide (LPS)-stimulated monocytes is available at the cell surface, only 10% to 20% of the total extractable TF activity is expressed on the surface of intact monocytes. Thus, most of the TF activity is latent or encrypted in the cell membrane. When coincubated, leukocytes and platelets generate more TF activity than either cell type alone. We have shown that such platelet-promoted enhancement of LPS-induced TF activity in monocytes in whole blood depends on neutrophil involvement in a P-selectin/CD15 (a leukocyte membrane-bound carbohydrate)-dependent reaction. The effect was even more pronounced when both the phorbol ester, phorbol 12-myristate 13-acetate (PMA), and LPS were present during monocyte stimulation. We currently envisage that decryption is mediated through the secretion of TF-rich particles by monocytes. These particles express CD15 and bind P-selectin exposed on either activated platelets or platelet-derived microparticles. Interactions and fusion events, that typically occur between monocytes and platelets, would facilitate the generation of monocytes/monocyte microparticle and platelets/platelet microparticle hybrids, leading to particles rich in decrypted TF activity. In conclusion, platelets play a pivotal role in decrypting TF activity of monocytes, generating a hybrid TF terrain, which both triggers and favors thrombogenesis.
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PMID:The role of platelets in decrypting monocyte tissue factor. 1173 2

Although about 80% of tissue factor (TF) extracellular domain antigen present in lipopolysaccharide (LPS)-stimulated monocytes is available at the cell surface, only 10% to 20% of the total extractable TF activity is expressed on the surface of intact monocytes. Thus, most of the TF activity is latent or encrypted in the cell membrane. When coincubated, leukocytes and platelets generate more TF activity than either cell type alone. We have shown that such platelet-promoted enhancement of LPS-induced TF activity in monocytes in whole blood depends on neutrophil involvement in a P-selectin/CD15 (a leukocyte membrane-bound carbohydrate)-dependent reaction. The effect was even more pronounced when both the phorbol ester, phorbol 12-myristate 13-acetate (PMA), and LPS were present during monocyte stimulation. We currently envisage that decryption is mediated through the secretion of TF-rich particles by monocytes. These particles express CD15 and bind P-selectin exposed on either activated platelets or platelet-derived microparticles. Interactions and fusion events, that typically occur between monocytes and platelets, would facilitate the generation of monocytes/monocyte microparticle and platelets/platelet microparticle hybrids, leading to particles rich in decrypted TF activity. In conclusion, platelets play a pivotal role in decrypting TF activity of monocytes, generating a hybrid TF terrain, which both triggers and favors thrombogenesis.
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PMID:The role of platelets in decrypting monocyte tissue factor. 1252 24

The angiotensin-converting enzyme inhibitor (ACE-I) enalapril has been shown to lower elevated levels of circulating adhesion molecules (cAM) in critically ill patients. To delineate the mechanisms of this possibly beneficial effect of enalapril, we studied the acute effects of enalapril in a well-defined model of endotoxin-triggered, cytokine-mediated cAM up-regulation. In a randomized, controlled trial, 30 healthy male volunteers received 2 ng/kg lipopolysaccharide (LPS) after pretreatment with placebo or 20 mg/day enalapril for 5 days or with a single dose of 20 mg of enalapril 2 h before LPS infusion. LPS infusion increased TNF levels 300-fold above normal, circulating (c) E-selectin levels by 425% (CI, 359%-492%), and P-selectin, VCAM-1, ICAM-1, and von Willebrand factor levels by 47%-74%. LPS infusion also enhanced ICAM-1 and CD11b expression 2- to 3-fold on monocytes. However, no differences were seen between treatment groups (P > 0.05), despite 95% inhibition of ACE activity by enalapril. Inhibition of ACE activity by enalapril does not influence plasma indices of endothelial activation after endotoxin infusion in healthy individuals. Our results do not support the concept of a beneficial clinical effect of enalaprilat in septicemia.
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PMID:Enalapril does not alter adhesion molecule levels in human endotoxemia. 1274 88


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