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Query: UNIPROT:P43026 (
lipopolysaccharide
)
62,215
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
We examined the effect of negative affect on changes in stimulated secretion of cytokines by blood monocytes and determined whether insulin resistance (IR), as indexed by the Homeostasis Model Assessment (HOMA), moderated these associations in 58 healthy men (aged 18-65 years). Blood samples and ratings of negative affect were collected at rest and 15min following subjects' participation in the Anger Recall Interview (ARI). Assessment of
lipopolysaccharide
(
LPS
)-stimulated secretion of IL-1beta, IL-6, and TNF-alpha was accomplished by ELISA of supernatant. Regression models controlling for age, body mass index, and race/ethnicity revealed that higher HOMA-IR values were associated with larger stress-induced increases in IL-1beta and TNF-alpha (p<.05). Furthermore, arousal of negative affect during the ARI was differentially associated with stress-induced changes in stimulated secretion of TNF-alpha and IL-6 as a function of HOMA-IR (p<.05). Increases in stimulated cytokine secretion were associated with arousal of negative affect, but only among men with higher HOMA-IR values. Among men with lower HOMA-IR values, arousal of negative affect was associated with diminished cytokine secretion. Collectively, these data suggest that the HOMA-IR moderates the impact that arousal of negative affect has on the ability of blood monocytes to secrete inflammatory cytokines in response to
LPS
. Stress-induced increases in cytokine secretion among high HOMA-IR men are consistent with the role of inflammation in
cardiovascular disease
, hypertension, type 2 diabetes as well as the metabolic syndrome and underscore the relevance of negative affect in the etiology of these inflammatory conditions.
...
PMID:Increases in stimulated secretion of proinflammatory cytokines by blood monocytes following arousal of negative affect: the role of insulin resistance as moderator. 1628 46
Statins are inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase used in the prevention of
cardiovascular disease
(
CVD
). In addition to their cholesterol-lowering activities, statins exert pleiotropic antiinflammatory effects, which might contribute to their beneficial effects not only on
CVD
but also on lipid-unrelated immune and inflammatory diseases, such as rheumatoid arthritis, asthma, stroke, and transplant rejection. However, the molecular mechanisms involved in these antiinflammatory properties of statins are unresolved. Here we show that the peroxisome proliferator-activated receptor (PPAR) alpha mediates antiinflammatory effects of simvastatin in vivo in models of acute inflammation. The inhibitory effects of statins on
lipopolysaccharide
-induced inflammatory response genes were abolished in PPARalpha-deficient macrophages and neutrophils. Moreover, simvastatin inhibited PPARalpha phosphorylation by
lipopolysaccharide
-activated protein kinase C (PKC) alpha. A constitutive active form of PKCalpha inhibited nuclear factor kappaB transrepression by PPARalpha whereas simvastatin enhanced transrepression activity of wild-type PPARalpha, but not of PPARalpha mutated in its PKC phosphorylation sites. These data indicate that the acute antiinflammatory effect of simvastatin occurs via PPARalpha by a mechanism involving inhibition of PKCalpha inactivation of PPARalpha transrepression activity.
...
PMID:Acute antiinflammatory properties of statins involve peroxisome proliferator-activated receptor-alpha via inhibition of the protein kinase C signaling pathway. 1639 46
The Toll-like receptor (TLR)4 is the major sensor for bacterial
lipopolysaccharide
and its two common co-segregating polymorphisms, Asp299Gly and Thr399Ile, which occur at a frequency of between 6 and 10%, have been associated with infectious diseases, LPS hypo-responsiveness and
cardiovascular disease
. Porphyromonas gingivalis is a Gram-negative bacterium implicated in chronic periodontitis and is a known TLR4 and TLR2 agonist. We obtained two gingival epithelial cell primary cultures from subjects heterozygous for the TLR4 polymorphism Asp299Gly and compared response characteristics with similar cells from patients (four) with the wild-type TLR4 genes. Cytokine responses and transcriptome profiles of gingival epithelial cell primary culture cells to TNFalpha challenge were similar for all primary epithelial cell cultures. P. gingivalis challenge, however, gave markedly different responses for Asp299Gly heterozygous and wild-type epithelial cell cultures. The epithelial cells heterozygous for the TLR4 polymorphism Asp299Gly were functionally hypo-responsive, evidenced by differences in BD-2 mRNA expression, mRNA response profile by microarray analysis and by pro-inflammatory and chemokine cytokines at the protein and mRNA level. These findings emphasize variance in human epithelial cell TLRs, linked with Asp299Gly carriage, which results in a hypo-responsive epithelial cell phenotype less susceptible to Gram-negative diseases and associated systemic conditions.
...
PMID:Gingival epithelial cells heterozygous for Toll-like receptor 4 polymorphisms Asp299Gly and Thr399ile are hypo-responsive to Porphyromonas gingivalis. 1643 23
Overproduction of nitric oxide by inducible nitric oxide synthase contributes to the progression of
cardiovascular disease
. We investigated the effects of azelnidipine and other Ca2+-channel blockers on nitric oxide production by cultured aortic smooth muscle cells isolated from Wistar rats and human umbilical vein endothelial cells (HUVECs), using the Griess reaction and oxyhemoglobin method. Release of lactic dehydrogenase (LDH) was measured to evaluate cell damage, and immunohistochemistry was performed to examine the expression of inducible nitric oxide synthase and nitrotyrosine protein. Azelnidipine and other Ca2+-channel blockers inhibited the release of nitric oxide induced by
lipopolysaccharide
plus interferon-gamma. Azelnidipine inhibited it most potently among the Ca2+-channel blockers tested (azelnidipine, amlodipine, nifedipine, diltiazem, verapamil, and nicardipine) at a concentration of 10 microM. Longer stimulation with these agents induced the expression of inducible nitric oxide synthase and nitrotyrosine, with an increase of lactic dehydrogenase release, whereas azelnidipine suppressed these changes. In human umbilical vein endothelial cells, azelnidipine enhanced basal nitric oxide production by endothelial nitric oxide synthase. In conclusion, azelnidipine potently inhibited the induction of inducible nitric oxide synthase and then nitric oxide production in vascular smooth muscle cells, while enhancing constitutive nitric oxide production by endothelial cells. Azelnidipine may inhibit nitrotyrosine expression and cell damage caused by overproduction of nitric oxide, suggesting a mechanism for its cardiovascular protective effect.
...
PMID:Comparative effects of azelnidipine and other Ca2+-channel blockers on the induction of inducible nitric oxide synthase in vascular smooth muscle cells. 1649 72
Prevention of
cardiovascular disease
through nutritional supplements is growing in popularity throughout the world. Multiple epidemiologic studies found that moderate consumption of alcohol, particularly red wine, lowers mortality rates from coronary heart diseases (CHD). Chronic inflammation and atherosclerosis associated with CHD culminate in aberrant intravascular expression of tissue factor (TF), which triggers blood coagulation leading to thrombosis, a major cause for heart attack. We showed earlier that two red wine phenolics, resveratrol and quercetin, suppressed TF induction in endothelial cells. In the present study, we investigated efficacy of seven resveratrol derivatives, which were shown to be effective in regulating cancer cell growth in vitro at much lower concentrations than the parent compound resveratrol, in inhibiting TF induction in peripheral blood mononuclear cells (PBMCs). We also tested possible synergistic effects of resveratrol and quercetin with the other major red wine phenolics in suppression of
lipopolysaccharide
-induced TF expression in human PBMCs. We found that several resveratrol derivatives were 2- to 10-fold more efficient than resveratrol in inhibiting TF induction. Our study found no evidence for synergism among red wine polyphenolics. These data suggest that structural alterations of resveratrol can be effective in producing potent antithrombotic agents that will have therapeutic potential in the improvement of cardiovascular health and prevention of CHD. Among major red wine phenolics, quercetin appears to be the predominant suppressor of TF induction.
...
PMID:Suppression of human monocyte tissue factor induction by red wine phenolics and synthetic derivatives of resveratrol. 1650 16
Cardiovascular disease
is an important complication of human immunodeficiency virus/acquired immune deficiency syndrome (AIDS), but the mechanism(s) involved are poorly understood. Although co-infecting pathogens have been implicated as an important factor in AIDS progression, no studies have investigated these interactions in cardiac tissue. We recently demonstrated that the murine AIDS model (LPBM5 retroviral infection) mimics human immunodeficiency virus-related cardiac dysfunction and pathology. We tested the hypothesis that subseptic
lipopolysaccharide
exposure (LPS) would enhance LPBM5 progression and exacerbate cardiovascular dysfunction during murine AIDS development. LPS (5 mg/kg, Escherichia coli 0111:B4) was administered at 1, 6, and 8 weeks during LPBM5 infection, and cardiac performance was evaluated at 10 weeks using noninvasive echocardiography. LPS alone had no significant effects, whereas it amplified abnormalities in cardiac structure and function observed in murine AIDS. Cardiac dysfunction was associated with selective increases in nonfocal infiltration of CD68(+) cells and correlated with the extent of cardiac dysfunction. Retroviral progression and cardiac retroviral content remained unaltered, but cardiac toll-like receptor 4 was increased in retrovirus + LPS. We provide first-time evidence of multipathogen enhancements to retrovirus-related cardiac complications and implicate innate immune responses, not co-pathogen-induced retroviral replication, as the primary mechanism in this setting.
...
PMID:Bacterial lipopolysaccharide enhances cardiac dysfunction but not retroviral replication in murine AIDS: roles of macrophage infiltration and toll-like receptor 4 expression. 1650 88
Epidemiological studies support that chronic periodontal infections are associated with an increased risk of
cardiovascular disease
. Previously, we reported that the periodontal pathogen Porphyromonas gingivalis accelerated atherosclerotic plaque formation in hyperlipidemic apoE-/- mice, while an isogenic fimbria-deficient (FimA-) mutant did not. In this study, we utilized 41 kDa (major) and 67 kDa (minor) fimbria mutants to demonstrate that major fimbria are required for efficient P. gingivalis invasion of human aortic endothelial cells (HAEC). Enzyme-linked immunosorbent assay (ELISA) revealed that only invasive P. gingivalis strains induced HAEC production of pro-inflammatory molecules interleukin (IL)-1beta, IL-8, monocyte chemoattractant protein (MCP)-1, intracellular adhesion molecule (ICAM)-1, vascular cellular adhesion molecule (VCAM)-1 and E-selectin. The purified native forms of major and minor fimbria induced chemokine and adhesion molecule expression similar to invasive P. gingivalis, but failed to elicit IL-1beta production. In addition, the major and minor fimbria-mediated production of MCP-1 and IL-8 was inhibited in a dose-dependent manner by P. gingivalis
lipopolysaccharide
(
LPS
). Both P. gingivalis
LPS
and heat-killed organisms failed to stimulate HAEC. Treatment of endothelial cells with cytochalasin D abolished the observed pro-inflammatory MCP-1 and IL-8 response to invasive P. gingivalis and both purified fimbria, but did not affect P. gingivalis induction of IL-1beta. These results suggest that major and minor fimbria elicit chemokine production in HAEC through actin cytoskeletal rearrangements; however, induction of IL-1beta appears to occur via a separate mechanism. Collectively, these data support that invasive P. gingivalis and fimbria stimulate endothelial cell activation, a necessary initial event in the development of atherogenesis.
...
PMID:Fimbria-dependent activation of pro-inflammatory molecules in Porphyromonas gingivalis infected human aortic endothelial cells. 1661 Dec 24
A growing literature suggests that psychosocial factors, such as chronic stress and depression, are associated with increased vulnerability to inflammatory disease; however, the mechanisms of this effect remain unclear. One possibility is that these psychosocial characteristics are associated with activation of innate inflammatory pathways. Here, we explore relationships between a range of psychosocial risk factors for inflammatory disease and a measure of inflammatory potential,
lipopolysaccharide
-induced production of the monocyte-derived proinflammatory cytokines/chemokines interleukin (IL)-1beta, IL-6, TNF-alpha, and IL-8 among a community sample of 183 healthy adults aged 30-54 years. After controlling for demographic factors, health behavior practices, blood pressure, and white blood cell count, hierarchical regression analyses revealed a positive relationship between production of IL-8 and symptoms of depression, trait negative affect, and perceived stress. In contrast, there was an inverse relationship between IL-8 production and perceived social support. Relationships between IL-8 and symptoms of depression and perceived stress were attributable primarily to dispositional differences in NA. The relationship between negative affect measures and IL-8 was independent of social support. Although there were significant univariate associations between higher IL-6 production and symptoms of depression and less social support, these relationships did not withstand adjustment for demographic controls. There were no significant associations between IL-1beta or TNF-alpha and any of the psychosocial parameters. Our findings suggest that individuals at greater psychosocial risk for the development of inflammatory diseases, including
cardiovascular disease
, also show greater stimulated production of the proinflammatory chemokine, IL-8. Further exploration of this potential psychophysiological pathway is warranted.
...
PMID:Stimulated production of interleukin-8 covaries with psychosocial risk factors for inflammatory disease among middle-aged community volunteers. 1699 40
C-reactive protein (CRP), the prototypical human acute phase protein, is an independent risk predictor of future cardiovascular events, both in healthy individuals and in patients with known
cardiovascular disease
. In addition, previous studies indicate that CRP might have direct proatherogenic properties. Ligand activation of the liver X receptor (LXR), a member of the nuclear hormone receptor superfamily, inhibits inflammatory gene expression in macrophages and attenuates the development of atherosclerosis in various animal models. We demonstrate herein that 2 synthetic LXR ligands, T0901317 and GW3965, inhibit interleukin-1beta/interleukin-6-induced CRP mRNA and protein expression in human hepatocytes. Knockdown of LXRalpha/beta by short interfering RNAs completely abolished the inhibitory effect of the LXR agonist T0901317 on cytokine-induced CRP gene transcription. Transient transfection experiments with 5'-deletion CRP promoter constructs identified a region from -125 to -256 relative to the initiation site that mediated the inhibitory effect of LXR ligands on CRP gene transcription. Depletion of the nuclear receptor corepressor by specific short interfering RNA increased cytokine-inducible CRP mRNA expression and promoter activity and reversed LXR ligand-mediated repression of CRP gene transcription. Chromatin immunoprecipitation assays indicated that nuclear receptor corepressor is present on the endogenous CRP promoter under basal conditions. Cytokine-induced clearance of nuclear receptor corepressor complexes was inhibited by LXR ligand treatment, maintaining the CRP gene in a repressed state. Finally, treatment of C57Bl6/J mice with LXR ligands attenuated
lipopolysaccharide
-induced mouse CRP and serum amyloid P component gene expression in the liver, whereas no effect was observed in LXRalphabeta knockout mice. Our observations identify a novel mechanism of inflammatory gene regulation by LXR ligands. Thus, inhibition of CRP expression by LXR agonists may provide a promising approach to impact initiation and progression of atherosclerosis.
...
PMID:A nuclear receptor corepressor-dependent pathway mediates suppression of cytokine-induced C-reactive protein gene expression by liver X receptor. 1711 May 95
Binge ethanol (EtOH) consumption suppresses inflammatory responses and resistance to infection, but paradoxically it is associated with increased levels of acute phase proteins (which are indicators of inflammation) and an increased risk of inflammation-mediated pathologies such as
cardiovascular disease
and cirrhosis of the liver. The latter effect may be mediated by increased translocation of bacteria leading to activation of toll-like receptor 4 (TLR4). In this study, the dose-response and time course of the effects of EtOH alone or EtOH in conjunction with a TLR4 agonist (
lipopolysaccharide
[LPS]) were evaluated in mice. EtOH alone at a dosage of 6 g/kg induced an acute phase response (as indicated by enzyme-linked immunosorbent assay for serum amyloid A and serum amyloid P) that was maximal 24 h after dosing. Lower dosages of EtOH did not have this effect but did suppress the acute phase response to LPS and the production of interleukin-6 up to 3 h after dosing. EtOH at 6 g/kg did not induce an acute phase response in C3H/HeJ (TLR4 mutant) mice, indicating that this response is mediated through TLR4. These results provide a resolution for the apparently paradoxical pro- and anti-inflammatory actions of EtOH with regard to acute phase responses.
...
PMID:An explanation for the paradoxical induction and suppression of an acute phase response by ethanol. 1713 63
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