Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Deleterious environmental stimuli cause the airway epithelium to respond with increased secretions of mucus, reaction of oxygen/nitrogen species, changes in ciliary beating, and the influx of inflammatory cells. The epithelium is a target for factors released by infiltrating inflammatory cells, and has recently been shown to serve as an effector of such inflammation. Molecular mechanisms regulating production of secondary inflammatory mediators (cytokines, lipid mediators, and reactive oxygen/nitrogen species) have yet to be fully described. This report reviews the production of secondary mediators by epithelial cells and by airway epithelium. Lipid mediators are enzymatically produced by the airway epithelium in response to primary mediators. Molecular mechanisms regulating the production of cyclo-oxygenase, lipoxygenase and prostaglandin synthase are discussed, along with the potential of lipid mediators to produce inflammation. The molecular regulation of nitric oxide production is also described in the context of its role as a signalling molecule in pathways regulating secretion of mucus, ciliary motion, and intercellular adhesion molecule-1 (ICAM-1) expression. The production of cytokines by the airway epithelium is shown to play a role in causing inflammation associated with respiratory diseases. Particular attention is paid to molecular mechanisms governing the expression of tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-8 (IL-8).
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PMID:Airway epithelium as an effector of inflammation: molecular regulation of secondary mediators. 931 17

1. The effect of liposome phospholipid composition has been assumed to be relatively unimportant because of the presumed inert nature of phospholipids. 2. We have previously shown that cationic liposome formulations used for gene therapy inhibit, through their cationic component, the synthesis by activated macrophages of the pro-inflammatory mediators nitric oxide (NO) and tumour necrosis factor-alpha (TNF-alpha). 3. In this study, we have evaluated the ability of different cationic lipids to reduce footpad inflammation induced by carrageenan and by sheep red blood cell challenge. 4. Parenteral (i.p. or s.c) or local injection of the positively charged lipids dimethyldioctadecylammomium bromide (DDAB), dioleyoltrimethylammonium propane (DOTAP), dimyristoyltrimethylammonium propane (DMTAP) or dimethylaminoethanecarbamoyl cholesterol (DC-Chol) significantly reduced the inflammation observed in both models in a dose-dependent manner (maximum inhibition: 70-95%). 5. Cationic lipids associated with dioleyol- or dipalmitoyl-phosphatidylethanolamine retained their anti-inflammatory activity while cationic lipids associated with dipalmitoylphosphatidylcholine (DPPC) or dimyristoylphosphatidylglycerol (DMPG) showed no anti-inflammatory activity, indicating that the release of cationic lipids into the macrophage cytoplasm is a necessary step for anti-inflammatory activity. The anti-inflammatory activity of cationic lipids was abrogated by the addition of dipalmitoylphosphatidylethanolamine-poly(ethylene)glycol-2000 (DPPE-PEG2000) which blocks the interaction of cationic lipids with macrophages. 6. Because of the significant role of protein kinase C (PKC) in the inflammatory process we have determined whether the cationic lipids used in this study inhibit PKC activity. The cationic lipids significantly inhibited the activity of PKC but not the activity of a non-related protein kinase, PKA. The synthesis of interleukin-6 (IL-6), which is not dependent on PKC activity for its induction in macrophages, was not modified in vitro or in situ by cationic lipids. The synthesis of NO and TNF-alpha in macrophages, both of which are PKC-dependent, was downregulated by cationic lipids. 7. These results demonstrate that cationic lipids can be considered as novel anti-inflammatory agents. The downregulation of pro-inflammatory mediators through interaction of cationic lipids with the PKC pathway may explain this anti-inflammatory activity. Furthermore, since cationic lipids have intrinsic anti-inflammatory activity, cationic liposomes should be used with caution to deliver nucleic acids for gene therapy in vivo.
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PMID:Anti-inflammatory activity of cationic lipids. 935 14

Use of marijuana and cocaine is on the rise in the United States. Although pulmonary toxicity from these drugs has occasionally been reported, little is known about their effects on the lung microenvironment. We evaluated the function of alveolar macrophages (AMs) recovered from the lungs of nonsmokers and habitual smokers of either tobacco, marijuana, or crack cocaine. AMs recovered from marijuana smokers were deficient in their ability to phagocytose Staphylococcus aureus (p < 0.01). AMs from marijuana smokers and from cocaine users were also severely limited in their ability to kill both bacteria and tumor cells (p < 0.01). Studies using NG-monomethyl-L-arginine monoacetate, an inhibitor of nitric oxide synthase, suggest that AMs from nonsmokers and tobacco smokers were able to use nitric oxide as an antibacterial effector molecule, while AMs from smokers of marijuana and cocaine were not. Finally, AMs from marijuana smokers, but not from smokers of tobacco or cocaine, produced less than normal amounts of tumor necrosis factor-alpha, granulocyte-macrophage colony-stimulating factor, and interleukin-6 when stimulated in culture with lipopolysaccharide. In contrast, the production of transforming growth factor-beta, an immunosuppressive cytokine, was similar in all groups. These findings indicate that habitual exposure of the lung to either marijuana or cocaine impairs the function and/or cytokine production of AMs. The ultimate outcome of these effects may be an enhanced susceptibility to infectious disease, cancer, and AIDS.
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PMID:Marijuana and cocaine impair alveolar macrophage function and cytokine production. 937 83

Cardiac hypertrophy and heart failure are frequently accompanied by elevated plasma levels of tumor necrosis factor alpha (TNF alpha), the pathogenetic relevance of this finding being a matter of debate. In human acute septic cardiomyopathy, on the other hand, the negative inotropic impact of TNF alpha on the heart is well documented and frequently ascribed to the induction of inducible nitric oxide (NO) synthase (iNOS) and an enhanced production of NO in the heart. Yet the present study presents evidence that in cardiomyocytes TNF alpha in non-toxic concentrations specifically depresses contractile performance independent of NO. In spontaneously beating neonatal rat cardiomyocytes, TNF alpha in a low, pathophysiologically relevant concentration (10 U/ml, 1-3 days) does not alter basal pulsation amplitude, but blocks alpha- and beta-adrenoceptor-stimulated increase in contractility and beating irregularity and impairs the impact of high extracellular calcium on contractile performance. However, this low TNF alpha-concentration does not suffice to induce iNOS - documented by reverse transcriptase polymerase chain reaction - or enhance nitrite concentrations in the cell culture supernatants as a measure of cellular NO production, neither in the presence nor absence of dexamethasone (0.1 micro M). Only in high concentration - the specific proinflammatory action being documented by an enhanced release of interleukin-6 from cardiomyocytes - TNF alpha (1000 U/mol; 6, 24 h) weakly induces the mRNA for iNOS, with a consecutive moderate rise in cellular nitrite production. TNF alpha-incubation (10-1000 U/ml) does not alter the morphological appearance of the cells displayed by phase contrast microscopy or evoke gross cytotoxicity.
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PMID:Tumor necrosis factor alpha (TNF alpha) is cardiodepressant in pathophysiologically relevant concentrations without inducing inducible nitric oxide-(NO)-synthase (iNOS) or triggering serious cytotoxicity. 940 66

We studied the pathways of macrophage response to lipopolysaccharide (LPS). When mouse macrophages pre-exposed to LPS were restimulated with this agent, reduced tumour necrosis factor-alpha (TNF-alpha) responses (desensitization/endotoxin tolerance) were accompanied by increased (priming) nitric oxide (NO) responses. Priming was also inducible with recombinant interferon-beta (IFN-beta). The requirement of TNF-alpha biosynthesis in the LPS-induced priming was also suggested by the observation that both anti-TNF-alpha serum and pentoxifylline inhibited this effect. However, addition of mouse recombinant TNF-alpha (mrTNF-alpha) did not enhance the priming induced by LPS or IFN-beta, and preincubation with mrTNF-alpha alone, or in association with other cytokines produced by macrophages (interleukin-1 beta, interleukin-6, or leukaemia inhibitory factor), did not induce a priming effect. We found however, that pentoxifylline, which blocked the priming, also decreased the level of membrane-bound TNF-alpha. Furthermore, exposure to compound BB-3103 (a metalloproteinase inhibitor that blocks the processing of membrane-bound TNF-alpha yielding to the secreted cytokine) enhanced the priming effect, the expression of membrane TNF-alpha and the specific binding of LPS. These observations suggest that the membrane form of TNF-alpha is involved in the interaction of LPS with a receptor required for LPS-induced priming.
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PMID:Involvement of the membrane form of tumour necrosis factor-alpha in lipopolysaccharide-induced priming of mouse peritoneal macrophages for enhanced nitric oxide response to lipopolysaccharide. 941 35

We have monitored glial cell line-derived neurotrophic factor (GDNF) secretion from rat C6 glioblastoma cells by ELISA. Representative cytokines, neurotrophins, growth factors, neuropeptides, and pharmacological agents were tested for their ability to modulate GDNF release. Whereas most factors tested had minimal effect, a 24-h treatment with fibroblast growth factor-1, -2, or -9 elevated secreted GDNF protein levels five- to 10-fold. The proinflammatory cytokines interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, and lipopolysaccharide elevated GDNF release 1.5- to twofold. Parallel studies aimed at elucidating intracellular events that may regulate GDNF synthesis/release demonstrated the involvement of multiple signaling pathways. GDNF levels were increased by phorbol 12,13-didecanoate (10 nM) activation of protein kinase C, the Ca2+ ionophore A23187 (1 microM), okadaic acid (10 nM) inhibition of type-2A protein phosphatases, nitric oxide donors (1 mM), and H2O2 (1 mM)-induced oxidative stress. Elevation of cyclic AMP levels by either forskolin (10 microM) or dibutyryl cyclic AMP (1 mM) repressed GDNF secretion, as did treatment with the glucocorticoid dexamethasone (1 microM). Our results demonstrate that diverse biological factors are capable of modulating GDNF protein levels and that multiple signal transduction systems can regulate GDNF synthesis and/or release.
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PMID:Regulation of glial cell line-derived neurotrophic factor release from rat C6 glioblastoma cells. 945 47

In situations of depressed myocardial function, the role of immunological mechanisms has been studied recently. In different pathophysiological situations, such as chronic heart failure, open heart surgery with extracorporal circulation, cardiac transplantation, myocardial infarction and angina pectoris, patterns have been described with elevation of proinflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-1, interleukin-6, and reversible myocardial dysfunction, which may represent a final common pathway. The available data suggest a modulation of important determinants of pump function, i.e., contractility, preload, afterload, and heart rate, by cytokines. Potential mechanisms include the beta-adrenoceptor- and nitric oxide pathway, as well as a direct impact on intracellular calcium homeostasis. Interventional strategies based on this understanding are beginning to emerge.
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PMID:[Proinflammatory cytokines and cardiac pump function]. 945 46

The relationship between plasma nitrite, nitrate, and nitric oxide (NOx), cytokines, and cardiac and vascular dysfunction after lipopolysaccharide (LPS) was studied in chronically instrumented anesthetized dogs. LPS was administered (1 mg/kg i.v.), and hemodynamics were recorded at baseline, every 15 min for 1 h, and every hour for an additional 14 h. Dramatic reductions in mean arterial pressure (-48 +/- 6%), cardiac output (-40 +/- 8%), stroke volume (-42 +/- 9%), and first derivative of left ventricular pressure (LV dP/dt, -38 +/- 7%) were seen within 1 h after injection of endotoxin. Cardiac output was not different from control by 9 h, whereas mean arterial pressure (-19 +/- 7%), stroke volume (-32 +/- 8%), and LV dP/dt (-21 +/- 10%) remained significantly depressed from control. Total peripheral resistance was not significantly different from control. Therefore, the hypotension appears to be due to a reduction in cardiac function and not to vasodilation. Levels of plasma NOx were not different from control until 4 h after LPS reached levels 597 +/- 126% higher than control at 15 h. In vitro production of nitrite by coronary microvessels was also elevated, supporting our in vivo findings. In contrast, production of tumor necrosis factor-alpha and interleukin-6 occurred shortly after endotoxin injection, reaching peak levels at 45 and 150 min, respectively. Our data suggest that inducible nitric oxide synthase induction occurred after LPS injection. It is unlikely that nitric oxide contributed significantly to the hypotension and cardiac dysfunction early in our study, whereas cardiodepressive cytokines, particularly tumor necrosis factor-alpha, may be important. In contrast, the hemodynamic effects seen late after injection of endotoxin may be the result of an overproduction of nitric oxide, since there was a sixfold increase in plasma NOx levels at this time and a marked production of nitric oxide in isolated coronary microvessels in vitro.
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PMID:Relationship between plasma NOx and cardiac and vascular dysfunction after LPS injection in anesthetized dogs. 945 68

There is a need for more insight into the pathogenesis of Streptococcus pneumoniae pneumonia, as the fatality rate associated with this disease remains high despite appropriate antibiotherapy. The host response to pneumococci was investigated after intranasal inoculation of CD1 mice with 10(7) log-phase CFU of bacteria. We identified five major pathogenesis steps from initial infection to death. In step 1 (0 to 4 h), there was ineffective phagocytosis by alveolar macrophages, with concurrent release of tumor necrosis factor alpha (TNF), interleukin-6 (IL-6), and nitric oxide (NO) in bronchoalveolar lavage (BAL) fluid, TNF, IL-6, and interleukin-1 alpha (IL-1) in lung tissues, and IL-6 in serum, which were associated with tachypnea and hemoconcentration. In step 2 (4 to 24 h), bacterial growth in alveoli and polymorphonuclear cell recruitment from bloodstream to lung tissue (high myeloperoxidase levels) to alveoli were associated with high release of all three cytokines and leukotriene B4 (LTB4) in tissue and BAL fluid, as well as transient spillover of IL-1 in serum. In step 3 (24 to 48 h), despite downregulation of TNF and IL-1 in BAL fluid and lungs, there was appearance of injury to alveolar ultrastructure, edema to interstitium, and increase in lung weight as well as regeneration of type II pneumocytes and increased secretion of surfactant; bacteria progressed from alveoli to tissue to blood, and body weight loss occurred. In step 4 (48 to 72 h), strong monocyte recruitment from blood to alveoli was associated with high NO release in tissue and BAL fluid, but there was also noticeable lymphocyte recruitment and leukopenia; bacteremia was associated with TNF and IL-6 release in blood and thrombocytopenia. In step 5 (72 to 96 h), severe airspace disorganization, lipid peroxidation (high malondialdehyde release in BAL fluid), and diffuse tissue damage coincided with high NO levels; there was further increase in lung weight and bacterial growth, loss in body weight, and high mortality rate. Delineation of the sequential steps that contribute to the pathogenesis of pneumococcal pneumonia may generate markers of evolution of disease and lead to better targeted intervention.
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PMID:Cytokine kinetics and other host factors in response to pneumococcal pulmonary infection in mice. 948 75

Endothelins (ETs), potent vasoconstricting peptides, are produced by macrophages upon stimulation and may participate in the amplification or regulation of the inflammatory response. However, it is not clear whether ETs can act in an autocrine manner on macrophages and which role they play in relationship with other cytokines. To address these issues, we studied the effects of ETs on the production of inflammatory cytokines by mouse peritoneal macrophages or by a retrovirus-transformed microglial cell line. Here, we report that ET-2, but not ET-1 or ET-3, is able to stimulate the production of interleukin-1 (IL-1) and interleukin-6 (IL-6) by peptone-elicited mouse macrophages (pMO). In contrast, ET-3 and ET-1, but not ET-2, are active on microglial cells. No tumour necrosis factor-alpha (TNF-alpha) or nitric oxide (NO) were detected in the supernatants of ET-stimulated cultures. The activity of ET-2 on pMO was time and dose dependent and was inhibited by the addition of ETA and ETB receptor antagonists, BQ123 and IRL1038, respectively. In addition, when pMO were stimulated by interferon-gamma (IFN-gamma) in the presence of ET-2, a significant inhibition of IL-6 and IL-1 production was observed compared with the effects of the same doses of IFN-gamma or ET-2 used separately. The inhibition was specifically due to the activity of ET-2, since it was reversed by the addition of BQ123 or IRL1038. Similar results were seen when the content of NO in the supernatants of pMO stimulated by IFN-gamma plus ET-2 was evaluated. These results suggest that ETs may possess both a pro-inflammatory action on macrophages from different tissues and a regulatory activity on IFN-gamma.
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PMID:Different endothelins stimulate cytokine production by peritoneal macrophages and microglial cell line. 953 26


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