Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tissue factor (TF) expression by endothelial cells is implicated in thrombotic episodes in patients with a variety of clinical disorders. In a baboon model of lethal sepsis, TF is expressed by endothelial cells in the splenic microvasculature. In vitro, endothelial cells are induced to express TF in response to tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and bacterial endotoxin (lipopolysaccharide [LPS]). Here, we identified cis-acting regulatory elements that control TF gene transcription in primary human endothelial cells. Functional studies showed that the TF promoter contained a 56-bp enhancer (-227 to -172 bp), which included two activator protein-1 (AP-1) sites and a kappa B-like site, that mediated induction by TNF-alpha, IL-1 beta, and LPS. Electrophoretic mobility shift assays demonstrated that endothelial cells contained constitutive AP-1 binding activity, whereas the kappa B-like site, 5'-CGGAGTTTCC-3', bound an inducible nuclear complex composed of c-Rel-p65 heterodimers. Taken together, our data suggest that induction of TF gene transcription in endothelial cells is mediated by functional interactions between Fos-Jun and c-Rel-p65 heterodimers.
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PMID:Transcriptional regulation of tissue factor expression in human endothelial cells. 774 75

Tissue factor (TF) expression by peripheral blood monocytes during sepsis initiates intravascular thrombosis. Bacterial lipopolysaccharide (LPS) rapidly induces TF gene transcription in monocytes. The human TF promoter contains binding sites for the transcription factors AP-1, c-Rel/p65, Egr-1, and Sp1. NF-kappa B/Rel proteins have been shown to physically interact with both AP-1 and Sp1 proteins. In this study, we investigated the role of these transcription factors in uninduced and LPS-induced TF gene expression in human monocytic THP-1 cells. Deletional analysis indicated that five Sp1 sites mediated basal expression in uninduced cells. The two AP-1 sites bound c-Fos/c-Jun heterodimers in both unstimulated and LPS-stimulated cells. Maximal LPS induction of the TF promoter required the two AP-1 sites and the kappa B site within the LPS response element. Disruption of the conserved spacing between the proximal AP-1 site and the kappa B site abolished LPS induction. Replacement of the two AP-1 sites with intrinsically bent DNA partially restored LPS induction, suggesting an additional structural role for the AP-1 sites. Synergistic transactivation of the LPS response element in Drosophila Schneider cells by coexpression of c-Fos, c-Jun, c-Rel, and p65 or c-Jun and p65 required the transactivation domains of c-Jun and p65. These data indicated that c-Fos/c-Jun, c-Rel/p65, and Sp1 regulate TF gene expression in human monocytic cells.
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PMID:Regulation of the tissue factor gene in human monocytic cells. Role of AP-1, NF-kappa B/Rel, and Sp1 proteins in uninduced and lipopolysaccharide-induced expression. 908 93

We studied the effect of PPM-18, a chemically synthesized naphthoquinone derivative and also an anti-inflammatory agent, on the lipopolysaccharide (LPS)-activated inducible NO synthase (iNOS) expression in rat alveolar macrophages. Pretreatment of macrophages with PPM-18 (0.1-10 microM) significantly inhibited nitrite production, iNOS protein expression and iNOS mRNA accumulation. PPM-18 did not directly affect the enzymic activities of iNOS and other constitutive NOS forms. The LPS-induced increase in nuclear transcription factor kappaB (NF-kappaB) p65 and p50 in nucleus was suppressed by PPM-18 (10 microM). Moreover electrophoretic mobility-shift assays demonstrated that PPM-18 inhibited DNA binding to NF-kappaB induced by LPS in whole cells but not when added in the nuclear extract, suggesting that PPM-18 did not interfere directly with the binding of NF-kappaB to DNA and that some events had to be processed before NF-kappaB could bind DNA. Examination of NF-kappaB showed that PPM-18 stabilized the NF-kappaB inhibitor, IkappaBalpha, by preventing its degradation from NF-kappaB. Therefore the stabilization of IkappaBalpha might have contributed to the inhibition of NF-kappaB activation. These results also indicate strongly that NF-kappaB is involved in the production of NO on stimulation by LPS. PPM-18 significantly decreased the production of tumour necrosis factor alpha in response to LPS. PPM-18 protects mice against LPS-induced lethal toxicity. These results also indicate that PPM-18 is a potent inhibitor of iNOS expression by blocking the binding of NF-kappaB to promoter and exerts a beneficial effect in the mouse model of sepsis.
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PMID:Inhibition of nitric oxide synthase expression by PPM-18, a novel anti-inflammatory agent, in vitro and in vivo. 937 89

Alterations in alveolar macrophage (AM) function during sepsis-induced hypoxia may influence tumor necrosis factor (TNF) secretion and the progression of acute lung injury. Nuclear factor (NF)-kappaB is thought to regulate the expression of endotoxin [lipopolysaccharide (LPS)]-induced inflammatory cytokines such as TNF, and NF-kappaB may also be influenced by changes in O2 tension. It is thus proposed that acute changes in O2 tension surrounding AMs alter NF-kappaB activation and TNF secretion in these lung cells. AM-derived TNF secretion and NF-kappaB expression were determined after acute hypoxic exposure of isolated Sprague-Dawley rat AMs. Adhered AMs (10(6)/ml) were incubated (37 degrees C at 5% CO2) for 2 h with LPS (Pseudomonas aeruginosa, 1 microgram/ml) in normoxia (21% O2-5% CO2) or hypoxia (1.8% O2-5% CO2). AM-derived TNF activity was measured with a TNF-specific cytotoxicity assay. Electrophoretic mobility shift and supershift assays were used to determine NF-kappaB activation and to identify NF-kappaB isoforms in AM extracts. In addition, mRNAs for selected AM proteins were determined with RNase protection assays. LPS-exposed AMs in hypoxia had higher levels of TNF (P < 0.05) and enhanced expression of NF-kappaB (P < 0.05); the predominant isoforms were p65 and c-Rel. Increased mRNA bands for TNF-alpha, interleukin-1alpha, and interleukin-1beta were also observed in the hypoxic AMs. These results suggest that acute hypoxia in the lung may induce enhanced NF-kappaB activation in AMs, which may result in increased production and release of inflammatory cytokines such as TNF.
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PMID:Acute hypoxia increases alveolar macrophage tumor necrosis factor activity and alters NF-kappaB expression. 1036 14

The onset of liver injury is a pivotal event during endotoxemia. Lipopolysaccharide (LPS) activates the Kupffer cells (KC), the resident macrophages of the liver, to generate an abundance of inflammatory substances, including nitric oxide (NO). Elevated levels of NO are thought to contribute to the propagation of liver injury during sepsis. Calcium, a major second messenger in several cellular signaling events, is required by the KC for the generation of inducible nitric oxide synthase (iNOS). The purpose of this study was to determine whether calcium channel antagonists limit hepatic injury and iNOS expression in vivo following LPS exposure and to evaluate their effects on the regulation of iNOS expression in cultured KC. In rats subjected to LPS for 6 h, the serum alanine aminotransferase (ALT) level was elevated significantly; this response was accompanied by an increase in iNOS mRNA formation in the intact liver. Pretreatment of rats with calcium channel antagonists (i.e., diltiazem, nifedipine, or verapamil) before LPS exposure attenuated the serum ALT level and iNOS mRNA expression in the liver. Pretreatment of cultured KC with calcium channel antagonists for 1 h followed by the addition of LPS markedly repressed iNOS protein and mRNA expression. Time-course studies revealed that calcium channel antagonists were most effective at inhibiting LPS-induced iNOS mRNA formation by KC when added before LPS. Treatment of KC with calcium channel antagonists prior to the addition of LPS decreased nuclear levels of the p65 subunit of nuclear factor-kappaB and prevented the LPS-dependent degradation of the inhibitory protein IkappaBalpha. Thus our findings indicate that under endotoxemic conditions calcium channel antagonists limit hepatocellular injury that is accompanied by an inhibition of LPS-mediated iNOS expression in rat liver KC.
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PMID:Effects of calcium channel antagonists on LPS-induced hepatic iNOS expression. 1044 49

Excessive nitric oxide (NO) generated by hepatic cells in response to lipopolysaccharide (LPS) and inflammatory substances (e.g., platelet-activating factor [PAF]) is a key contributor to the pathophysiological outcomes observed in the liver during sepsis. In rats subjected to liver-focused endotoxemia, inducible nitric oxide synthase (iNOS) levels in the intact liver were elevated by 6 hours; cell-specific expression of iNOS messenger RNA (mRNA) was Kupffer cells (KCs), endothelial cells, and hepatocytes. Elevated serum alanine transaminase (ALT) levels at 6 hours confirmed hepatic damage. Pretreatment of endotoxemic rats with PAF receptor antagonists BN 50739 or WEB 2170 reduced serum ALT and iNOS mRNA levels in the intact liver. Pretreatment of cultured KCs with BN 50739 or WEB 2170 inhibited both LPS and PAF-induced iNOS mRNA formation. In addition, LPS-induced iNOS protein levels in KCs pretreated with BN 50739 or WEB 2170 were decreased. Exposure of KCs to either LPS or PAF caused the translocation of the p65 subunit of nuclear factor kappa B (NF-kappaB) into the nucleus and this process was attenuated by BN 50739 and WEB 2170. There was concomitant inhibition of LPS-dependent degradation of the inhibitory protein IkappaBalpha and increase in intracellular Ca(2+) in KC treated with BN 50739 or WEB 2170. Also, in KCs, LPS was able to induce iNOS mRNA expression independent of CD14. This response was inhibited by pretreatment of KCs with either BN 50739 or WEB 2170. Our findings indicate that PAF receptor antagonists convey protection against hepatocellular injury accompanied by a decrease in nitric oxide (NO) formation in the livers of endotoxemic rats.
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PMID:Suppression of lipopolysaccharide-induced nitric oxide synthase expression by platelet-activating factor receptor antagonists in the rat liver and cultured rat Kupffer cells. 1053 42

Neutrophil (PMN) apoptosis regulates local and systemic inflammation during sepsis. Tumor necrosis factor receptor-associated factors (TRAFs) have been implicated as mediators of apoptosis; however, the signaling pathways for their production in stimulated PMN are unclear. We hypothesize that NF-kappaB translocation is necessary for the induction of TRAF-1 in PMNs with prolonged survival. Neutrophils were isolated from the blood of healthy volunteers by Ficoll gradient centrifugation and red blood cell sedimentation. Neutrophil NF-kappaB was inhibited with a proteasome inhibitor, PSI-I. Cells were treated with PSI-I (30 microM) or vehicle (DMSO 0.2%) for 50 min then incubated over an 18-h time course with LPS (10 to 1000 ng/mL), tumor necrosis factor alpha (TNFalpha) (2 to 20 ng/mL) or control media. In vitro apoptosis was quantified by propidium iodide FACS analysis. Total cellular TRAF-1 was detected by Western blot analysis of cell lysates. Steady state TRAF-1 mRNA was detected by RPA. NF-kappaB activity was determined by Western blot analysis for nuclear p65. Means and standard errors were calculated; data were analyzed by ANOVA. Lipopolysaccharide (LPS) and TNFalpha increased PMN nuclear p65 and steady state TRAF-1 mRNA. Apoptosis was inhibited by TNFalpha and LPS at 12 and 18 h (P < 0.01). Incubation of cells in the NF-kappaB inhibitor PSI-I blocked LPS and TNFalpha-induced inhibition of apoptosis (P < 0.05) and the induction of both nuclear p65 and TRAF-1 mRNA. These data demonstrate that inhibition of PMN apoptosis and TRAF-1 induction by LPS and TNFalpha is NF-kappaB dependent.
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PMID:Inhibited neutrophil apoptosis: proteasome dependent NF-kappaB translocation is required for TRAF-1 synthesis. 1102 45

The expression of NF-kappaB was studied in freshly isolated peripheral blood mononuclear cells (PBMC) of patients with severe sepsis and major trauma. The expression of p65p50 heterodimer, the active form of NF-kappaB, was significantly reduced for all patients as compared with control subjects. The p50p50 homodimer, an inhibitory form of NF-kappaB, was reduced in the survivors of sepsis and in patients with trauma. Subsequent in vitro stimulation of PBMC with lipopolysaccharide (LPS) did not induce further NF-kappaB nuclear translocation: the survivors of sepsis and trauma patients showed low expression of both p65p50 and p50p50, whereas nonsurvivors of sepsis showed a predominance of the inactive homodimer and a low p65p50/p50p50 ratio when compared with control subjects. In the later group of patients there was a reverse correlation between plasma IL-10 levels and the p65p50/p50p50 ratio after in vitro LPS stimulation (r = -0.8, p = 0.04). The reduced expression of nuclear NF-kappaB was not due to its inhibition by IkappaBalpha, as very low expression of IkappaBalpha, as well as low levels of p65 and p50 were found in the cytoplasm of PBMC from patients with sepsis and trauma when compared with control subjects. These results demonstrate that upon LPS activation, PBMC of patients with systemic inflammatory response syndrome show patterns of NF-kappaB expression that resemble those reported during LPS tolerance: global down-regulation of NF-kappaB in survivors of sepsis and trauma patients and the presence of large amounts of the inactive homodimer in the nonsurvivors of sepsis.
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PMID:NF-kappaB expression in mononuclear cells of patients with sepsis resembles that observed in lipopolysaccharide tolerance. 1106 29

The present study was designed to investigate the role of NF-kappaB in influencing the outcome of sepsis modulated by previous heat shock treatment. Sepsis was induced in rats by cecum ligation and puncture (CLP) method, which manifests two distinct clinical phases: an initial hyperdynamic phase (9 h after CLP, early sepsis) followed by a hypodynamic phase (18 h after CLP, late sepsis). Rats of heated group were treated by whole body hyperthermia 24 h prior to the CLP operation. Lymphocytes were collected during the early and late sepsis phases. The expressions of Hsp72, p65 and I-kappa B were evaluated by Western blot and immunochemical analysis. NF-kappaB activity was detected by EMSA. The results showed that NF-kappaB activation was initiated during early sepsis and apparently suppressed during late stage of sepsis. Previously treated by heat shock, late-sepsis rats emerged with high preservation of p65 expression and NF-kappaB activity, while Hsp72 was over-expressed. In conclusion, down-regulation of NF-kappaB activity during late sepsis could be attenuated by pretreatment of heat shock through the preservation of p65 expression. The results may provide a mechanistic explanation for the improved outcome to polymicrobial sepsis of rats that are preconditioned with heat shock, as well as a novel highlight for therapeutic intervention of severe infection.
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PMID:Potential protective effect of NF-kappaB activity on the polymicrobial sepsis of rats preconditioning heat shock treatment. 1107 60

Macrophage activation plays a central role in host defense against a variety of pathogens via inducible messengers. The transcription factor NF-kappaB controls the synthesis of cytokines involved in immune responses. In quiescent cells, NF-kappaB is located in the cytosol bound to an inhibitor IkappaB. Upon appropriate signal, NF-KB translocates to the nucleus and binds to DNA. The present study investigated the involvement of an immunomodulator, (diHDA-glycerol) on the NF-kappaB/IkappaB complex. Results were compared to those obtained with lipopolysaccharide (LPS) as a major virulence factor in bacterial sepsis. Data showed that exposure of J774.1 cells either to LPS or diHDA-glycerol substantially increased with time the nuclear levels of NF-kappaB complexes. Antibodies to various NF-kappaB proteins supershifted p50, p65 and to a lesser extent c-rel. Western blot analyses showed a rapid cytosolic IkappaB-alpha turn over following LPS exposure in contrast to diHDA-glycerol treatment. Further experiments investigated the involvement of protein kinase C (PKC) by using two inhibitors, staurosporine and H7. Pretreatment of J774.1 with either inhibitor prior to diHDA-glycerol or LPS exposure decreased NF-kappaB activation. Our results indicate that diHDA-glycerol was acting on NF-kappaB through IkappaB regulative mechanisms differing from those used by LPS. DiHDA-glycerol is likely acting on many other transcription factors targeting distinct genes implied in up regulation of the immune system.
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PMID:Effect of a synthetic lipid immunomodulator on the regulation of the transcription factor NF-kappaB. 1110 79


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