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)

The purpose of this study was to determine if interleukin (IL)-10 inhibits lipopolysaccharide (LPS)-induced IL-6 production in microglia by inhibiting activation of nuclear factor-kappaB (NF-kappaB). N13 microglia (a murine microglial cell line) and primary microglia from neonatal mice were cultured in the presence or absence of LPS and increasing amounts of murine IL-10 for 24 h. As predicted, LPS treatment increased supernatant IL-6 concentration in both N13 and primary microglia cultures. Pretreatment with IL-10, however, decreased LPS-induced IL-6 secretion in a dose-dependent manner in both culture systems. Likewise, ribonuclease protection assays showed that LPS increased steady-state IL-6 mRNA levels, but that pretreatment with IL-10 blocked the LPS-induced increase in IL-6 mRNA. Because NF-kappaB is the predominant transcription factor responsible for IL-6 transcription in response to inflammatory stimuli, it was hypothesized that IL-10 inhibited IL-6 production by preventing nuclear translocation of NF-kappaB. Consistent with this idea, LPS increased nuclear translocation of NF-kappaB as assessed by gel mobility shift assay. Supershift assays and immunocytochemical staining showed that both the p50 and p65 subunits of NF-kappaB translocated from the cytoplasm to the nucleus upon LPS stimulation. Pretreatment with IL-10, however, inhibited LPS-induced activation of NF-kappaB. Furthermore, inhibition of NF-kappaB activity with tosyl-Phe-chloromethlyketone (a serine protease inhibitor that prevents degradation of the NF-kappaB-IkappaB complex), completely blocked LPS-induced IL-6 production. These data suggest that IL-10 inhibited IL-6 production in microglia by decreasing the activity of NF-kappaB and, therefore, extend what little is known of the intricate relationship between anti-inflammatory and inflammatory cytokines in the central nervous system.
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PMID:Interleukin (IL)-10 inhibits IL-6 production in microglia by preventing activation of NF-kappaB. 1081 40

Dendritic cells (DC) are highly-specialized antigen-presenting cells (APC), that initiate and modulate immune responses. Their specialized migratory and tissue-homing properties are regulated by small molecular weight proteins (chemokines) that govern leukocyte migration and activation. Little is known about the capacity of liver DC to produce or respond to chemokines. Here we examined chemokine and chemokine receptor (CR) gene expression in both immature DC progenitors (DCp) and comparatively mature DC generated from mouse liver. Factors affecting production of the chemokine macrophage inflammatory protein (MIP)-1alpha, and the influence of MIP-1alpha on liver DC migration were also investigated. Dendritic cells were propagated in response to granulocyte-macrophage colony stimulating factor (GM-CSF) +/- interleukin (IL)-4 from bone marrow (BM) cells or liver non-parenchymal cells (NPC) isolated from normal mice, or from mice treated with the hematopoietic growth factor Flt3 ligand (FL). Their phenotype and allostimulatory function were assessed by monoclonal antibody (mAb) staining and flow cytometry, and by the capacity to induce mixed leukocyte reactions, respectively. Specific chemokine and CR gene expression was studied using the RNase protection assay (RPA). Production of MIP-1alpha was determined by enzyme-linked immunoabsorbent assay (ELISA), and the migratory activity of liver DC induced by MIP-1alpha quantitated using microchemotaxis chambers. Like DC generated simultaneously from BM, liver-derived DC expressed mRNA for a variety of CC and CXC chemokines. RANTES (regulated upon activation, normal T cell expressed and secreted) transcripts were the most strongly expressed. Gene transcripts for the receptor CCR1, that binds RANTES and MIP-1alpha were also readily detected, as was CCR2, the receptor for the monocyte chemotactic proteins (MCP)1-4. No major differences in chemokine or CR mRNA expression were detected between immature and more mature liver DC. MIP-1alpha production by liver-derived DC was stimulated by bacterial lipopolysaccharide (LPS), and high levels were also detected in co-cultures of hepatic DC and allogeneic T cells. Chemotactic migration of liver-derived DC was stimulated by MIP-1alpha. Thus, liver-derived DC express mRNA for several CC and CXC chemokines and their receptors that may play key roles in the regulation of hepatic inflammatory responses. Production of MIP-1alpha by liver DC, and their migratory responses to this chemokine, suggest that MIP-1alpha and other chemokines may play significant roles in the regulation of liver DC function and in interactions of liver DC with other leukocytes, under normal and inflammatory conditions.
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PMID:Chemokine and chemokine receptor expression by liver-derived dendritic cells: MIP-1alpha production is induced by bacterial lipopolysaccharide and interaction with allogeneic T cells. 1083 7

Classic ischemic preconditioning transiently (30 to 120 minutes) protects the myocardium against subsequent lethal ischemia/reperfusion injury. After dissipation of this acute protection, a second window of protection (SWOP) appears 12 to 24 hours later; this SWOP lasts up to 3 days. Several triggers induce a SWOP, including brief repetitive cycles of coronary artery occlusion, rapid ventricular pacing, stimulation of adenosine A(1) receptors, and administration of wall fragments of Gram-negative bacteria, such as lipopolysaccharide (LPS). The aim of this study was to investigate whether lipoteichoic acid (LTA), a cell wall fragment of Gram-positive bacteria, can induce a SWOP in a rat model of left anterior descending coronary artery (LAD) occlusion (25 minutes) and reperfusion (2 hours). Thus, 166 male Wistar rats were pretreated (2 to 24 hours) with saline, LTA (1 mg/kg IP), or LPS (1 mg/kg IP) and subjected to LAD occlusion/reperfusion. Pretreatment with LTA or LPS for 16 hours led to a substantial, approximately 65%, reduction in infarct size and a reduction in the release of cardiac troponin T into the plasma. The dose of LTA used had no toxic effect (on any of the parameters studied), whereas the same dose of LPS caused a time-dependent activation of the coagulation system and liver injury. By use of RNase protection assays, it was determined that LPS caused a time-dependent induction of tumor necrosis factor-alpha, interleukin-1beta, and manganese superoxide dismutase mRNA content in the heart, whereas LTA failed to induce manganese superoxide dismutase. LPS also caused an upregulation of the expression of intercellular adhesion molecule-1 and P-selectin, whereas LTA downregulated these molecules and attenuated the accumulation of polymorphonuclear granulocytes caused by myocardial ischemia/reperfusion. This study demonstrates for the first time that pretreatment with LTA at 8 to 24 hours before myocardial ischemia significantly reduces (1) infarct size, (2) cardiac troponin T, and (3) the histological signs of tissue injury in rats subjected to LAD occlusion and reperfusion. The mechanism(s) underlying the observed cardioprotective effects of LTA warrants further investigation but is likely to be related to its ability to inhibit the interactions between the coronary vascular endothelium and polymorphonuclear granulocytes. Therefore, LTA represents a novel and promising agent capable of enhancing myocardial tolerance to ischemia/reperfusion injury.
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PMID:Lipoteichoic acid induces delayed protection in the rat heart: A comparison with endotoxin. 1084 67

CRF receptor type 2 (CRF R2) messenger RNA (mRNA) expression in the rodent heart is modulated by exposure to both the bacterial endotoxin lipopolysaccharide (LPS) and glucocorticoids. In this study we examined the roles of glucocorticoids, cytokines, and CRF R2beta ligands in the regulation of CRF R2beta expression in the cardiovascular system both in vivo and in vitro. Using ribonuclease protection assays, we found that, in addition to the injection of LPS or corticosterone, physical restraint caused a decrease in CRF R2beta mRNA levels in the rat heart and aorta. Adrenalectomy with corticosterone replacement at constant levels partially blocked LPS-induced decreases in CRF R2beta mRNA expression in the heart. Thus, elevations of endogenous circulating corticosterone could contribute to the down-regulation of CRF R2beta mRNA expression in heart. To identify other putative modulating factors, we examined CRF R2beta expression in the aorta-derived A7R5 cell line. Incubation with CRF R2 ligands or dexamethasone reduced CRF R2beta mRNA levels. In addition, incubation with a variety of cytokines, proteins released during immune challenge, also reduced CRF R2beta mRNA expression. The multifactorial regulation of CRF R2beta mRNA expression in the cardiovascular system may serve to limit the inotropic and chronotropic effects of CRF R2 agonists such as urocortin during prolonged physical or immune challenge.
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PMID:Regulation of corticotropin-releasing factor receptor type 2 beta messenger ribonucleic acid in the rat cardiovascular system by urocortin, glucocorticoids, and cytokines. 1087 27

-CD36 is 1 of the class B scavenger receptor expressed on monocytes, monocyte-derived macrophages (Mphi), platelets, and adipocytes. In our previous studies, we reported that the uptake of oxidized low density lipoproteins (OxLDLs) is reduced by approximately 50% in Mphi from CD36-deficient patients compared with that in control subjects. Recently, we have shown that CD36 is highly expressed in human atherosclerotic aorta. Possibilities have been raised that besides the wide distribution and multifunctional characteristics of CD36, this molecule may also be involved in the mediation of intracellular signaling. The aim of the present study was to elucidate the role of CD36 in cytokine secretion and to investigate the CD36-mediated intracellular signaling stimulated by OxLDL. On addition of OxLDL or thrombospondin-1, the Mphi from CD36-deficient patients secreted significantly less amounts of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) compared with those from controls. RNase protection assay with multiprobe template sets demonstrated that after incubation with OxLDL, the mRNAs of a variety of cytokines, including genes encoding IL-1Ra, IL-1beta, IL-6, TNF-alpha and -beta, and interferon (IFN)-gamma and -beta, were significantly lower in the Mphi of patients. The addition of antibody against CD36 attenuated this OxLDL-induced response in controls. We also observed a reduced response in nuclear factor-kappa B (NF-kappa B) activity in OxLDL-stimulated Mphi from CD36-deficient patients. Unlike OxLDL, stimulation by lipopolysaccharide induced an increase in NF-kappa B activity in Mphi from CD36-deficient patients, suggesting that lipopolysaccharide-mediated signaling was conserved. These results demonstrate that in addition to the reduced OxLDL uptake that we reported previously, CD36-deficient patients may also have an impaired response of OxLDL-induced NF-kappa B activation and subsequent cytokine expression.
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PMID:Oxidized LDL-induced NF-kappa B activation and subsequent expression of proinflammatory genes are defective in monocyte-derived macrophages from CD36-deficient patients. 1093 17

Serotonin (5-HT) up-regulates B and T lymphocyte proliferation by activating mitogen-induced cell surface 5-HT(1A) receptors. The mechanism of 5-HT(1A) receptor induction by B and T cell mitogens at the mRNA and protein levels in mouse splenocytes was addressed. Quantitation by RNase protection assay showed maximal increases of 3.4-, 3.0-, 3.8-, and 4.9-fold in relative 5-HT(1A) mRNA levels after 48 h of stimulation of splenocytes with lipopolysaccharide, phytohemagglutinin, concanavalin A, or phorbol 12-myristate 13-acetate plus ionomycin, respectively, as compared with unstimulated cells. Mitogens did not alter 5-HT(1A) mRNA stability (t(12) = 26 h), but induction of 5-HT(1A) mRNA was blocked by the transcriptional inhibitor actinomycin D (10 microgram/ml) and by inhibition of nuclear factor-kappaB signaling. Additionally, mitogenic stimulation of transcription was paralleled by increased cell surface 5-HT(1A) receptor immunoreactivity in splenocytes. Thus, mitogen-induced 5-HT(1A) receptor expression appears to involve transcriptional regulation by the nuclear factor-kappaB signaling cascade. Increased expression of the 5-HT(1A) receptor in activated B and T lymphocytes may enhance the immune response and provide therapeutic target for tissue inflammation and immune stimulation.
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PMID:Transcriptional mechanisms for induction of 5-HT1A receptor mRNA and protein in activated B and T lymphocytes. 1108 Apr 94

Congenic strains of mice which differ only in their H2 haplotype were used to examine the effects of MHC genes on production of pro-inflammatory cytokines, as we have shown previously that H2(b) mice produce low levels of T cell cytokines compared to congenic H2(k) and H2(d) mice. RNase protection assays were used to assess cytokine mRNA and cytokine protein was assessed by ELISA or bioassay. Concanavalin A or phorbol myristate acetate/calcium ionophore/anti-CD3 stimulation of spleen cells from H2(b) congenic mice induced less IL-1, IL-2, IFN-gamma and MIF mRNA and/or protein than the equivalent cells from H2(d) mice. However, following stimulation with lipopolysaccharide or phorbol myristate acetate/calcium ionophore, peritoneal cells from H2(b) mice synthesised significantly more IL-1 beta, TNF-alpha, TNFR and IFN-gamma protein and IFN-gamma mRNA than cells from congenic H2(k) or H2(d) mice. These differences were evident in congenic C57BL/10 and/or BALB/c strains. We suggest that the low IL-1 production in H2(b) spleen cultures is secondary to lower T cell activation. Evidence that the H2(b) haplotype carries an immunoregulatory allele which affects cytokine production warrants further investigation.
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PMID:The H2(b) haplotype modifies the production of pro-inflammatory cytokines: implications for immunopathology. 1112 8

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

Calprotectin, a heterodimer of MRP8 and MRP14 with antimicrobial properties, is found in the cytosol of neutrophils, monocytes, and human gingival keratinocytes. During inflammation of the oral mucosa, the expression of immunoreactive calprotectin appears upregulated. Given the possible cell sources, we sought to learn if epithelial cells upregulate calprotectin in response to proinflammmatory agents. First, human gingival keratinocytes were maintained in primary culture until senescence. At each passage, cells were harvested and analyzed for quantitative expression of MRP8 and MRP14 subunit mRNA by RNase protection assays and calprotectin complex by enzyme-linked immunosorbent assay. Calprotectin expression was constitutive in the primary gingival keratinocytes, but calprotectin-specific mRNA and protein tended to increase as the cells neared senescence. To test whether calprotectin expression was inducible, immortalized gingival keratinocyte cultures were treated for 2 to 4 h with lipopolysaccharide (LPS) or interleukin-1 beta (IL-1 beta). As a positive control for inducible expression, immortalized keratinocytes were incubated with phorbol myristate acetate (PMA) (50 ng/ml) for 24 h. Incubation with PMA stimulated increased expression of MRP8 and MRP14 mRNA within 2 h, peaking within 5 h. MRP8- and MRP14-specific mRNA expression by immortalized keratinocytes appeared to be unaffected by LPS or IL-1 beta. In contrast, LPS, IL-1 beta, and PMA each upregulated IL-8. These data show that calprotectin mRNA is expressed constitutively in cultured keratinocytes, while expression by immortalized cells appears to be independent of the exogenous proinflammatory agents LPS and IL-1 beta.
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PMID:Calprotectin expression by gingival epithelial cells. 1129 47

Tumor necrosis factor (TNF)-alpha plays a key role in the pathogenesis of septic shock syndrome, and myocardial TNF-alpha expression may contribute to this pathophysiology. We examined the myocardial expression of TNF-alpha-related cytokines and chemokines in mice exposed to lipopolysaccharide (LPS) and tested the effects of anti-TNF therapy on myocardial cytokine expression. Cytokine mRNA levels were measured by RNase protection assay, and protein levels in the plasma and myocardium were assessed by enzyme-linked immunosorbent assays. LPS (4 microg/g body wt ip) induced marked cytokine expression, including TNF-alpha, interleukin (IL)-1beta, IL-6, and monocyte chemotactic protein (MCP)-1, in both the plasma and myocardium. Pretreatment with adenovirus-mediated TNF receptor fusion protein (AdTNFR1; 10(9) plaque-forming units iv) decreased plasma cytokine levels. In contrast, whereas myocardial IL-1beta expression was also suppressed, expression of IL-6 and MCP-1 was not inhibited by AdTNFR1. In summary, anti-TNF treatment differentially altered the cytokine expression in the plasma and myocardium during endotoxemia. Inability to block myocardial expression of IL-6 and MCP-1 suggests a possible mechanism for the failure of anti-TNF therapies in the treatment of endotoxin shock.
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PMID:Effects of soluble TNF receptor treatment on lipopolysaccharide-induced myocardial cytokine expression. 1129 32


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