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)

We have previously proposed that pro-inflammatory cytokines and nitric oxide (NO) contributed to reversible myocardial depression in patients with sepsis and congestive heart failure. Sepsis and heart failure are also associated with refractoriness to beta-adrenoceptor agonists. Therefore, the chronotropic effects of cytokines and the NO synthase inhibitor, NG-methyl-L-arginine (NMA), on beta-adrenoceptor stimulation of neonatal cardiac myocytes were studied. Tumor necrosis factor alpha, interleukin-1 beta and interleukin-6 but not interleukin-4 or interleukin-5 significantly enhanced spontaneous beating rates compared to untreated myocytes in serum-free media for 48 h (P < 0.01; n = 12 for each). NMA also significantly enhanced spontaneous beating rates (P < 0.01; n = 12 for each). Only interleukin-1 beta treatment resulted in significant nitrite production, immunohistochemical staining for inducible nitric oxide synthase and detection of inducible NO synthase messenger RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). However, tumor necrosis factor alpha, interleukin-1 beta, interleukin-6, and NMA each completely blocked the positive chronotropic effects of the beta-adrenoceptor agonist, isoproterenol (P < 0.01; n = 12 for each). These findings are most consistent with an inducible NO synthase-independent effect of cytokines and NMA on the chronotropic responses of neonatal cardiac myocytes to beta-adrenoceptor stimulation. This effect of cytokines and NMA on adrenergic signaling may involve a myocardial constitutive NO synthase or an NO-independent mechanism.
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PMID:Cytokines and nitric oxide synthase inhibitor as mediators of adrenergic refractoriness in cardiac myocytes. 905 50

We examined the effect of interleukin-6 on the levels of cGMP and nitrite in rat hippocampal slices. Interleukin-6 at 400 ng/ml time dependently increased the content of cGMP of slices after incubation for 1, 2, 3, and 4 h, and the effect of interleukin-6 was maximal at 2 h post-incubation. In addition, exposure of slices to interleukin-6 at 80, 400 and 2000 ng/ml or at 16, 80 and 400 ng/ml for 2 h significantly elevated the cGMP level and nitrite level, respectively, in a concentration-dependent manner. Also, 0.1 mM NG-nitro-L-arginine alone showed no effect on either the cGMP level or the nitrite level. However when incubated in conjunction with 400 ng/ml interleukin-6 for 2 h, NG-nitro-L-arginine apparently prevented the increase in cGMP and nitrite induced by 400 ng/ml interleukin-6. The present results show that NO mediates the increase in cGMP induced by interleukin-6 and suggest that interleukin-6 may exert an inducible effect on the NO synthase in hippocampal slices.
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PMID:Interleukin-6 increases the levels of cyclic GMP and nitrite in rat hippocampal slices. 908 46

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

We assessed two strains of mice [CD-1 and C3H.HeJ (C3H)] with different responses to coxsackievirus B3 (CVB3) infection at 7, 14, and 21 days after inoculation with 10(5) pfu of CVB3. CD-1 mice developed inflammatory lesions at 7 days that nearly recovered by 21 days; C3H mice demonstrated persistence of infiltrates. Although there were differences in the baseline fractional shortening, it was further reduced at 7 and 14 days in both strains. It recovered in CD-1 mice but remained depressed at 21 days in C3H mice. Interleukin-6 and tumor necrosis factor-alpha transcripts were increased in both strains at 7 days. Levels dropped to near control in CD-1 mice at 21 days but remained elevated in C3H mice. Interleukin-1 beta was minimally elevated in CD-1 mice but increased progressively in C3H mice. mRNA for the inducible form of NO synthase (iNOS) was increased at 7 days in the CD-1 mice, returning to baseline by 14 days; it rose progressively in C3H mice, with a fivefold increase at 21 days. We conclude that mice infected with CVB3 show increased expression of proinflammatory cytokines as well as iNOS associated with reduced contractile performance. In more susceptible mice, contractile depression and cytokine and iNOS expression are more pronounced.
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PMID:Contractile depression and expression of proinflammatory cytokines and iNOS in viral myocarditis. 945 74

1. The release of cytokines following administration of endotoxin and the contribution of nitric oxide (NO) to the subsequent haemodynamic profile were investigated in the conscious mouse. 2. Administration of endotoxin (E. Coli, 026:B6, 12.5 mg kg(-1), i.v.) elevated the concentration of tumour necrosis factor-alpha (TNF-alpha) in the plasma within 0.5 h, reaching a maximum at 2 h and returning to control concentrations by 4 h. In addition, the concentration of interleukin-6 (IL-6) in the plasma was also elevated within 1 h, reaching a maximum at 3 h and remaining elevated throughout the 12 h of study. 3. Endotoxin (12.5 mg kg(-1), i.v.) induced the expression of a Ca2+-independent (inducible) NO synthase in the mouse heart and elevated the concentrations of nitrite and nitrate in the plasma within 4 h, reaching a maximum at 12 h. This was accompanied by a progressive fall in blood pressure over the same period. 4. The vasopressor effect of noradrenaline (0.5-4 microg kg(-1) min(-1), i.v.) administered as a continuous infusion was significantly attenuated 7 h after endotoxin (12.5 mg kg(-1), i.v). 5. The NO synthase inhibitor NG-monomethyl-L-arginine HCl (L-NMMA; 1-10 mg kg(-1), i.v. bolus) reversed the fall in blood pressure when administered 7 h after endotoxin (12.5 mg kg(-1), i.v.). 6. In an attempt to maintain a constant blood concentration, L-NMMA was administered as a continuous infusion (10 mg kg(-1) h(-1), i.v.), beginning 4 h after a lower dose of endotoxin (6 mg kg(-1), i.v.). Such treatment prevented the fall in blood pressure and the elevation of nitrite and nitrate in the plasma throughout the 18 h of observation. 7. The fall in blood pressure following endotoxin (3 mg kg(-1), i.v.) was significantly reduced throughout the 18 h of observation in homozygous mutant mice lacking the inducible NO synthase. 8. In summary, we have developed a model of endotoxin shock in the conscious mouse in which an overproduction of NO by the inducible NO synthase is associated with the haemodynamic disturbances. This model, which exhibits many of the characteristics of septic shock in man, will enable the study of the pathology of this condition in more detail and aid the investigation of potential therapeutic agents both as prophylactics and, more importantly, as treatments.
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PMID:Nitric oxide and the haemodynamic profile of endotoxin shock in the conscious mouse. 964 79

Cytokines play a significant role in the regulation of Toxoplasma gondii in the central nervous system. Cytokine-activated microglia are important host defense cells in central nervous system infections. Recent evidence indicates that astrocytes can also be activated by cytokines to inhibit intracellular pathogens. In this study, we examined the effect of gamma interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and IL-1 on the growth of T. gondii in a primary murine astrocyte culture. Pretreatment of astrocytes with IFN-gamma resulted in 65% inhibition of T. gondii growth. Neither TNF-alpha, IL-1, nor IL-6 alone had any effect on T. gondii growth. IFN-gamma in combination with either TNF-alpha, IL-1, or IL-6 caused a 75 to 80% inhibition of growth. While nitric oxide was produced by astrocytes treated with these cytokines, inhibition of T. gondii growth was not reversed by the addition of the nitric oxide synthase inhibitor NG-monomethyl-L-arginine. Furthermore, IFN-gamma in combination with IL-1, IL-6, or TNF-alpha also induced inhibition in astrocytes derived from syngeneic mice deficient in the enzyme inducible nitric oxide synthase. This finding suggests that the mechanism of cytokine inhibition is not nitric oxide mediated. Similarly, the addition of tryptophan had no effect on inhibition, indicating that the mechanism was not mediated via induction of the enzyme indoleamine 2, 3-dioxygenase. The mechanism of inhibition remains to be elucidated. Results from this study demonstrate that cytokine-activated astrocytes are capable of significantly inhibiting the growth of T. gondii. These data indicate that astrocytes may be important host defense cells in controlling toxoplasmosis in the brain.
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PMID:Effect of cytokines on growth of Toxoplasma gondii in murine astrocytes. 974 8

Previous data from our laboratory have shown that calcitonin gene-related peptide (CGRP) has a potentiating effect on lipopolysaccharide-(LPS) induced interleukin-6 (IL-6) release from mouse macrophages. However, the mechanism of this effect was not clear. Since the nitric oxide (NO) and prostaglandins (PGs) induced by LPS might modulate IL-6 release, we examined whether NO and PGs were also involved in the potentiating effect of rat CGRP (rCGRP) on LPS-induced IL-6 release from mouse macrophages. The IL-6 level in the medium was measured by enzyme-linked immunosorbent assay. Accumulation of NO was assessed by measuring the presence of nitrite by the Greiss reaction. PGI2 was assessed by measuring the formation of 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha) by radioimmunoassay. The results showed that the potentiating effect of rCGRP (0.1 nm) on LPS-induced IL-6 release was significantly inhibited by either 100 micrometers NG-monomethyl-L-arginine acetate (L-NMMA; an inhibitor of NO synthase) or 10 micrometers indomethacin (an inhibitor of cyclo-oxygenase). The LPS-induced NO and PGI2 production from these cells was increased significantly by rCGRP at 0.01-10 nm in a concentration-dependent manner, which was blocked by L-NMMA and indomethacin. These results suggest that rCGRP enhances the NO production elicited by LPS and subsequently increases the PGs production which is involved in the potentiating effect of rCGRP on LPS-induced IL-6 release from the peritoneal macrophages in the mouse.
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PMID:Role of nitric oxide and prostaglandins in the potentiating effects of calcitonin gene-related peptide on lipopolysaccharide-induced interleukin-6 release from mouse peritoneal macrophages. 1023 92

There is controversy over whether nitric oxide (NO) mediates acute negative inotropic actions of cytokines including tumor necrosis factor-alpha (TNF- alpha). The reports from established laboratories have appeared inconsistent, which could be due to species differences. Thus, we tried to elucidate the mechanisms underlying negative inotropic actions of interleukin-6 (IL-6) and TNF- alpha in the same model. We studied the effects of cytokines on [Ca(2+)](i)transients (using indo-1), cell shortening (CS) (using a video motion detector) and the L-type Ca(2+)channel current (I(Ca)) (using the whole cell perforated patch clamp technique) in isolated guinea-pig ventricular myocytes. IL-6 (1000 U/ml) or TNF- alpha (500 U/ml) decreased both peak systolic [Ca(2+)](i)(IL-6: 0.43+/-0.01 to 0.40+/-0.01, n=5, P<0.05; TNF- alpha : 0.42+/-0.02 to 0.39+/-0.02, n=5, P<0.05) and the amplitude of CS (IL-6: 7.5+/-0.9 to 6.2+/-0.5 micrometers, n=5, P<0.05; TNF- alpha : 6.7+/-0.7 to 5.8+/-0.7 micrometers, n=5, P<0.05) without detectable reductions in I(Ca)(IL-6: 0.9+/-0.1 to 0.9+/-0.1 nA, n=4, N.S.; TNF- alpha : 1.1+/-0.3 to 1.1+/-0.2 nA, n=4, N.S.) within 5 min. The nitric oxide synthase (NOS) inhibitor, N(G)-monomethyl- L arginine (300 micromol/l), blocked the effects of IL-6 but not of TNF- alpha. When pretreated with 20 nmol/l isoproterenol, exposure to IL-6 decreased both I(Ca)(2.8+/-0.5 to 2. 0+/-0.3 nA) and the amplitude of CS (10.4+/-2.4 to 7.5+/-1.9 micrometer) within 5 min. TNF- alpha also clearly depressed I(Ca)(2.9+/-0.9 to 2.3+/-0.7 nA) and the amplitude of CS (7.0+/-1.4 to 5.5+/-1.3 micrometer) in beta -adrenergic stimulated cells. TNF- alpha significantly increased the content of sphingosine (product of sphingomyelin pathway) in isolated heart. The effects of low dose sphingosine (5 micromol/l) mimicked those of TNF- alpha on cardiac myocytes. IL-6 produced an acute negative inotropic effect through a NO-dependent pathway while TNF- alpha did so via a sphingomyelin-dependent pathway in isolated guinea-pig ventricular myocytes.
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PMID:Cellular basis for the acute inhibitory effects of IL-6 and TNF- alpha on excitation-contraction coupling. 1042 44

The aim of the current article is to overview the recent developments in the field of hemorrhagic shock research, as it relates to the roles of nitric oxide (NO) in the pathogenesis of this condition. The first part of the review focuses on the roles of peroxynitrite, a reactive oxidant produced from the reaction of NO and superoxide. The second part of the review deals with the novel findings related to the recently identified regulatory roles of the inducible isoform of nitric oxide synthase (iNOS) in the expression of pro-inflammatory mediators in hemorrhagic shock. (1) The role of peroxynitrite: Immunohistochemical and biochemical evidence demonstrate the production of peroxynitrite in hemorrhagic shock. Peroxynitrite can initiate a wide range of toxic oxidative reactions. These include initiation of tyrosine nitration, lipid peroxidation, direct inhibition of mitochondrial respiratory chain enzymes, inactivation of glyceraldehyde-3-phosphate dehydrogenase, inhibition of membrane sodium/potassium ATP-ase activity, inactivation of membrane sodium channels, and other oxidative modifications of proteins. All these toxicities are likely to play a role in the pathophysiology of hemorrhagic shock. A combined anti-inflammatory agent, mercaptoethylguanidine, which selectively inhibits iNOS and scavenges peroxynitrite, prevents the delayed vascular decompensation and the cellular energetic failure associated with late hemorrhagic shock. Peroxynitrite is a potent trigger of DNA single strand breakage, with subsequent activation of the nuclear enzyme poly (ADP ribose) synthetase (PARS), leading to eventual severe energy depletion of the cells, and necrotic-type cell death. Pharmacological inhibition of PARS, with 3-aminobenzamide or 5-iodo-6-amino-1,2-benzopyrone, improves hemodynamic status and prolongs survival time in rodent and porcine models of severe hemorrhagic shock. (2) Novel signaling roles of induced NO in hemorrhagic shock. Although the severity and duration of shock may dictate the timing and extent of iNOS expression, it is now evident that the up-regulation of iNOS can take place during sustained shock. Accumulated data indicate that iNOS expressed during shock contributes to vascular decompensation, as classically described by Wiggers. In addition, the presence of even low levels of iNOS at the time of resuscitation enhances the inflammatory response that follows the reperfusion state. Pharmacological inhibition of iNOS with N6-(iminoethyl)-L-lysine or genetic inactivation of iNOS (iNOS knockout mice) attenuates the activation of the transcription factors nuclear factor kappa B (NFkappaB) and Signal Transducer and Activator of Transcription 3 (STAT3), and ameliorates the increases in interleukin-6 and G-CSF messenger RNA levels in the lungs and liver. Inhibition of iNOS results in a marked reduction of lung and liver injury produced by hemorrhagic shock. Thus, induced nitric oxide, in addition to being a "final common mediator" of hemorrhagic shock, is essential for the up-regulation of the inflammatory response in resuscitated hemorrhagic shock. Furthermore, a picture of a pathway is evolving that contributes to tissue damage both directly via the formation of peroxynitrite, with its associated toxicities, and indirectly through the amplification of the inflammatory response.
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PMID:Novel roles of nitric oxide in hemorrhagic shock. 1046 45

Our previous study has demonstrated the potentiation by uridine triphosphate (UTP) of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production in lipopolysaccharide (LPS)-stimulated murine J774 macrophages. In this study, we found that the amount of interleukin-6 (IL-6) release in response to LPS stimulation was greatly enhanced in the presence of UTP. This enhancement exhibited concentration dependence and occurred after 8 h of treatment with LPS. RT-PCR analysis indicated that the steady-state level of IL-6 mRNA induced by LPS was apparently increased upon co-addition of UTP. The potentiation by UTP was inhibited by the treatment with U73122 (a phosphatidylinositol-phospholipase C inhibitor), BAPTA/AM (an intracellular Ca(2+) chelator), KN-93 (a selective inhibitor of calmodulin-dependent protein kinase) or PDTC (a nuclear factor kappaB inhibitor). To understand the cross-regulation among NO, PGE(2) and IL-6, all of which are dramatically induced after LPS stimulation, the effects of L-NAME (a nitric oxide synthase inhibitor), indomethacin (a cyclooxygenase inhibitor), NS-398 (a cycloxygenase-2 inhibitor) and IL-6 antibody were tested. The results revealed the positive regulation between PGE(2) and IL-6 synthesis because NS-398 and indomethacin inhibited LPS plus UTP-induced IL-6 release, and IL-6 antibody attenuated LPS plus UTP-induced PGE(2) release. Taken together these results reinforce the role of UTP as a regulatory element in inflamed sites by demonstrating the capacity of this nucleotide to potentiate LPS-induced release of inflammatory mediators.
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PMID:Potentiation of lipopolysaccharide-induced IL-6 release by uridine triphosphate in macrophages: cross-interaction with cyclooxygenase-2-dependent prostaglandin E(2) production. 1054 78


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