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)

Streptococcus agalactiae is the leading cause of bacterial sepsis and meningitis in neonates and also the causative agent of different serious infections in immunocompromised adults. The wide range of diseases that are caused by S. agalactiae suggests regulatory mechanisms that control the formation of specific virulence factors in these bacteria. The present study describes a gene from S. agalactiae, designated rogB, encoding a protein with significant similarity to members of the RofA-like protein (RALP) family of transcriptional regulators. Disruption of the rogB gene in the genome of S. agalactiae resulted in mutant strain RGB1, which was impaired in its ability to bind to fibrinogen and fibronectin. Mutant RGB1 also exhibited a reduced adherence to human epithelial cells but did not show an altered invasion of eukaryotic cells. By real-time PCR analysis, mutant RGB1 revealed an increased expression of the cpsA gene, encoding a regulator of capsule gene expression. However, strain RGB1 exhibited a reduced expression of the rogB gene and of two adjacent genes, encoding putative virulence factors in S. agalactiae. Furthermore, mutant RGB1 was impaired in the expression of the fbsA gene, coding for a fibrinogen receptor from S. agalactiae. The altered gene expression in mutant RGB1 could be restored by plasmid-mediated expression of rogB, confirming a RogB deficiency as the cause for the observed changes in virulence gene expression in S. agalactiae. Reporter gene studies with a promotorless luciferase gene fused to fbsA allowed a growth-dependent analysis of fbsA expression in S. agalactiae. These reporter gene studies also suggest that RogB exerts a positive effect on fbsA expression in S. agalactiae.
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PMID:Analysis of RogB-controlled virulence mechanisms and gene repression in Streptococcus agalactiae. 1293 48

Plasminogen activator inhibitor-1 (PAI-1) is the major inhibitor of plasminogen activation and likely plays important roles in coronary thrombosis and arteriosclerosis. Tumor necrosis factor-alpha (TNFalpha) is one of many recognized physiological regulators of PAI-1 expression and may contribute to elevated plasma PAI-1 levels in sepsis and obesity. Although TNFalpha is a potent inducer of PAI-1 expression in vitro and in vivo, the precise location of the TNFalpha response site in the PAI-1 promoter has yet to be determined. Transient transfection studies using luciferase reporter constructs containing PAI-1 promoter sequence up to 6.4 kb failed to detect a response to TNFalpha. Moreover, TNFalpha failed to induce expression of enhanced green fluorescent protein under the control of a 2.9-kb human PAI-1 promoter in transgenic mice, although endogenous murine PAI-1 was strongly induced. These data suggested that the TNFalpha response element in the PAI-1 gene is remote from the proximal promoter region. In this study, seven candidate regulatory regions were identified using cross-species sequence homology analysis as well as DNase I-hypersensitive site analysis. We identified a 5' distal TNFalpha-responsive enhancer of the PAI-1 gene located 15 kb upstream of the transcription start site containing a conserved NFkappaB-binding site that mediates the response to TNFalpha. This newly recognized site is fully capable of binding NFkappaB subunits p50 and p65, whereas overexpression of the NFkappaB inhibitor IkappaB prevents TNFalpha-induced activation of this enhancer element.
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PMID:Tumor necrosis factor alpha activates the human plasminogen activator inhibitor-1 gene through a distal nuclear factor kappaB site. 1496 43

The cyclooxygenase-2 (Cox-2) gene plays a role in a variety of normal and pathophysiological conditions. Expression of the Cox-2 gene is induced in a broad range of cells, in response to many distinct stimuli. The ability to monitor and quantify Cox-2 expression noninvasively in vivo may facilitate a better understanding of the role of Cox-2, both in normal physiology and in different diseases. We generated a "knock-in" mouse in which the firefly luciferase reporter enzyme is expressed at the start site of translation of the endogenous Cox-2 gene. Correlation of luciferase and Cox-2 expression was confirmed in heterozygous Cox-2luc/+ mouse embryonic fibroblasts isolated from the knock-in mouse. In an acute sepsis model, following injection of interferon gamma and endotoxin, ex vivo imaging and Western blotting demonstrated coordinate Cox-2 and luciferase induction in multiple organs. Using both paw and air pouch inflammation models, we can monitor repeatedly localized luciferase expression in the same living mouse. Cox-2luc/+ knock-in mice should provide a valuable tool to analyze Cox-2 expression in many disease models.
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PMID:Imaging cyclooxygenase-2 (Cox-2) gene expression in living animals with a luciferase knock-in reporter gene. 1655 23

We have previously shown that wound healing was improved in a diabetic mouse model of impaired wound healing following transfection with keratinocyte growth factor-1 (KGF-1) cDNA. We now extend these findings to the characterization of the effects of DNA plasmid vectors delivered to rats using electroporation (EP) in vivo in a sepsis-based model of impaired wound healing. To assess plasmid transfection and wound healing, gWIZ luciferase and PCDNA3.1/KGF-1 expression vectors were used, respectively. Cutaneous wounds were produced using an 8 mm-punch biopsy in Sprague-Dawley rats in which healing was impaired by cecal ligation-induced sepsis. We used National Institutes of Health image analysis software and histologic assessment to analyze wound closure and found that EP increased expression of gWIZ luciferase vector up to 53-fold compared with transfection without EP (p < 0.001). EP-assisted plasmid transfection was found to be localized to skin. Septic rats had a 4.7 times larger average wound area on day 9 compared with control (p < 0.001). Rats that underwent PCDNA3.1/KGF-1 transfection with EP had 60% smaller wounds on day 12 compared with vector without EP (p < 0.009). Quality of healing with KGF-1 vector plus EP scored 3.0 +/- 0.3 and was significantly better than that of 1.8 +/- 0.3 for treatment with vector alone (p < 0.05). We conclude that both the rate and quality of healing were improved with DNA plasmid expression vector for growth factor delivered with EP to septic rats.
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PMID:Delivery of plasmid DNA expression vector for keratinocyte growth factor-1 using electroporation to improve cutaneous wound healing in a septic rat model. 1701 75

We recently used positional cloning to identify the transcription factor Nrf2 (NF-E2 related factor 2) as a susceptibility gene in a murine model of oxidant-induced acute lung injury (ALI). NRF2 binds to antioxidant response elements (ARE) and up-regulates protective detoxifying enzymes in response to oxidative stress. This led us to investigate NRF2 as a candidate susceptibility gene for risk of development of ALI in humans. We identified multiple single nucleotide polymorphisms (SNPs) by resequencing NRF2 in ethnically diverse subjects, and one (-617 C/A) significantly (P<0.001) diminished luciferase activity of promoter constructs containing the SNP and significantly decreased the binding affinity (P<0.001) relative to the wild type at this locus (-617 CC). In a nested case-control study, patients with the -617 A SNP had a significantly higher risk for developing ALI after major trauma (OR 6.44; 95% CI 1.34, 30.8; P=0.021) relative to patients with the wild type (-617 CC). This translational investigation provides novel insight into the molecular mechanisms of susceptibility to ALI and may help to identify patients who are predisposed to develop ALI under at risk conditions, such as trauma and sepsis. Furthermore, these findings may have important implications in other oxidative stress related illnesses.
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PMID:Functional polymorphisms in the transcription factor NRF2 in humans increase the risk of acute lung injury. 1738 44

We recently showed that A(2A) adenosine receptor activation by endogenous adenosine contributes to interleukin-10 (IL-10) production in polymicrobial sepsis. Here we investigated the molecular mechanisms underpinning this interaction between adenosine receptor signaling and infection by exposing macrophages to Escherichia coli. We demonstrated using receptor knockout mice that A(2A) receptor activation is critically required for the stimulatory effect of adenosine on IL-10 production by E coli-challenged macrophages, whereas A(2B) receptors have a minor role. The stimulatory effect of adenosine on E coli-induced IL-10 production did not require toll-like receptor 4 (TLR4) or MyD88, but was blocked by p38 inhibition. Using shRNA we demonstrated that TRAF6 impairs the potentiating effect of adenosine. Measuring IL-10 mRNA abundance and transfection with an IL-10 promoter-luciferase construct indicated that E coli and adenosine synergistically activate IL-10 transcription. Sequential deletion analysis and site-directed mutagenesis of the IL-10 promoter revealed that a region harboring C/EBP binding elements was responsible for the stimulatory effect of adenosine on E coli-induced IL-10 promoter activity. Adenosine augmented E coli-induced nuclear accumulation and DNA binding of C/EBPbeta. C/EBPbeta-deficient macrophages failed to produce IL-10 in response to adenosine and E coli. Our results suggest that the A(2A) receptor-C/EBPbeta axis is critical for IL-10 production after bacterial infection.
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PMID:A2A adenosine receptors and C/EBPbeta are crucially required for IL-10 production by macrophages exposed to Escherichia coli. 1752 87

Lipopolysaccharide (LPS) antagonists inhibit the response of inflammatory cells to LPS, presumably by competitive inhibition, and may be of therapeutic value in the treatment of endotoxemia and sepsis. The inhibitory effects of some LPS antagonists are restricted to certain host species, however, as the same molecules can have significant endotoxic activity in other species. This species-specific recognition appears to be mediated by Toll-like receptor 4 (TLR4) and/or MD-2. We have shown previously that LPS from Rhodobacter sphaeroides ( RsLPS) is an LPS antagonist in human cells but an agonist (or LPS mimetic) in equine cells. In the present study, HEK293 cells were transfected with combinations of human and equine CD14, TLR4 and MD-2, and incubated with either RsLPS or with LPS from Escherichia coli as an endotoxin control. NF-kappaB activation was measured in a dual luciferase assay as an indicator of cellular activation. Our results indicate that E. colic LPS activated NF-kappaB in cells transfected with all combinations of the three receptor proteins, whereas RsLPS activated NF-kappaB only in cells expressing the single combination of equine TLR4 and equine MD-2. We conclude that the TLR4/MD-2 complex is responsible for recognition of RsLPS as an agonist in equine cells.
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PMID:The equine TLR4/MD-2 complex mediates recognition of lipopolysaccharide from Rhodobacter sphaeroides as an agonist. 1795 42

Severe sepsis remains an important cause of death, particularly among trauma and burn patients. The severity of the systemic inflammatory response after trauma or burns and susceptibility to sepsis vary among individuals. One possible mechanism is through differential effects on glucocorticoid receptor (GR) expression by pro-inflammatory mediators (e.g. lipopolysaccharide signaling). In a mouse burn model, we demonstrated differential GR levels, size, and transcriptional activity in CD14 knockout (KO) mice when compared to wild-type (C57BL/6J) after injury. Sequence analysis revealed only 8 CAG repeats in the GR transactivation domain in the CD14 KO; the wild-type contained seventeen. A survey of genomic DNA from 51 mouse strains demonstrated CAG repeat length range from 7 - 17. We then studied the effect of polymorphism in CAG repeat length on GR activity. Fragments with CAG repeats varying from 8-40 (8, 17, 30, 38, and 40) were engineered and shuttled into the wild-type GR expression vector. The resulting plasmids were then co-transfected with a glucocorticoid response element linked to a luciferase in order to compare their transactivation potentials. Transactivation potential was highest in the 17-CAG GR. The effect of GR polymorphisms on GR activity warrants more research as this data suggests a mechanism for the individual differences in response to steroid treatment and the response to injury.
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PMID:The effect of CAG repeat length polymorphism in the murine glucocorticoid receptor on transactivation potential. 1853 20

Bacterial lipopolysaccharide (LPS) is a major inducer of systemic inflammatory reactions and oxidative stress in response to microbial infections and may cause sepsis. In the present study, we demonstrate that retinoic acid inhibits LPS-induced activation in transgenic reporter mice and human monoblasts through inhibition of nuclear factor kappaB (NF-kappaB). By using noninvasive molecular imaging of NF-kappaB luciferase reporter mice, we showed that administration of retinoic acid repressed LPS-induced whole-body luminescence, demonstrating in vivo the dynamics of retinoic acid's ability to repress physiologic response to LPS. Retinoic acid also inhibited LPS-induced NF-kappaB activity in the human myeloblastic cell line U937. Retinoic-acid-receptor-selective agonists mimicked - while specific antagonists inhibited - the effects of retinoic acid, suggesting the involvement of nuclear retinoic acid receptors. Retinoic acid also repressed LPS-induced transcription of NF-kappaB target genes such as IL-6, MCP-1 and COX-2. The effect of retinoic acid was dependent on new protein synthesis, was obstructed by a deacetylase inhibitor and was partly eliminated by a signal transducer and activator of transcription-1 (STAT1)/methyltransferase inhibitor, indicating that retinoic acid induces a new protein, possibly STAT1, that is involved in inhibiting NF-kappaB. This provides more evidence for retinoic acid's anti-inflammatory potential, which may have clinical implications in terms of fighting microbial infections.
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PMID:Retinoic acid dampens LPS-induced NF-kappaB activity: results from human monoblasts and in vivo imaging of NF-kappaB reporter mice. 1892 86

The reduced pressure response to norepinephrine during sepsis has directed our interest to the regulation of alpha1-adrenergic receptors. Because nuclear factor (NF)-kappaB occupies a prominent role in the inflammatory cascade, we hypothesized that NF-kappaB downregulates alpha1-receptors by liberation of proinflammatory cytokines and thereby contributes to septic circulatory failure. Sepsis was induced by cecal ligation and puncture (CLP) in wild-type mice and mice with deficiencies for proinflammatory cytokines, and mice were injected with TNF-alpha, IL-1beta, IFN-gamma, or IL-6. Animals were treated with glucocorticoids or small interfering RNA (siRNA) targeting multiple cytokines and NF-kappaB. Vascular smooth muscle cells were incubated with cytokines and calcium mobilization, mRNA stability assays, and promoter studies with alpha1-promoter-luciferase constructs were performed. Cecal ligation and puncture treatment resulted in a hyperdynamic circulatory failure, diminished calcium response to norepinephrine, and a significant downregulation of alpha1-receptors. Proinflammatory cytokines also downregulated alpha1-receptors by suppressing promoter activity at the level of gene transcription. However, suppression of single proinflammatory cytokines in cytokine knockout mice did not diminish CLP-induced downregulation of alpha1-receptors. In contrast, blocking multiple cytokines via siRNA pretreatment or glucocorticoid administration attenuated CLP-induced cardiovascular failure and downregulation of alpha1-receptors. Furthermore, inhibiting NF-kappaB activity by siRNA reduced the production of cytokines, prevented circulatory failure and downregulation of alpha1-receptors, and improved survival of septic mice. Our findings indicate that NF-kappaB has a central role in augmenting proinflammatory cytokine production during sepsis, which in turn downregulates alpha1-receptor expression. Our data further define a critical role for NF-kappaB in the pathogenesis of septic shock, indicating that targeting NF-kappaB is a desired therapeutic strategy to treat septic vasoplegia.
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PMID:Inhibition of NF-kappaB activity prevents downregulation of alpha1-adrenergic receptors and circulatory failure during CLP-induced sepsis. 1910 15


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