Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The process of signal transduction by interleukin 1 (IL-1) or tumor necrosis factor alpha (TNF alpha) for the production of hematopoietic growth factors by cultured fibroblasts was studied using inhibitors for protein kinase C, cyclic nucleotide-dependent protein kinases, calmodulin-dependent protein kinases, and the Na(+)-H+ antiport system. The protein kinase C inhibitor H-7 was shown to inhibit both IL-1 beta- and TNF alpha-induced granulocyte-macrophage colony-stimulating activity (GM-CSA) production and release from cultured fibroblasts in a dose-dependent manner, with 40 microM H-7 demonstrating maximum suppression of the GM-CSA response. In addition, 100-200 nM staurosporine, a more potent inhibitor of protein kinase C, also completely suppressed GM-CSA from IL-1 beta- and TNF alpha-induced fibroblasts. In contrast, a potent inhibitor of cyclic nucleotide-dependent protein kinases, HA1004, showed no effect when used at 10-40 microM. In addition, an inhibitor of calmodulin-induced protein kinases, W-7, also showed no effect when used at 10-30 microM. Prior incubation with H-7 did not inhibit the ability of fibroblasts to subsequently respond to IL-1 beta or TNF alpha, nor did H-7 directly inhibit the granulocyte-macrophage colony-forming assay. Both dibutyryl cyclic adenosine monophosphate (10-30 microM) and forskolin (1-100 nM), activators of adenylate cyclase, in the presence or absence of the phosphodiesterase inhibitor isobutylmethylxanthine, failed to stimulate a GM-CSA response from cultured fibroblasts, indicating a lack of effect of cyclic nucleotide-dependent protein kinases. Furthermore, the addition of H-7 30 min after induction with IL-1 beta or TNF alpha showed little effect on the synthesis of GM-CSA by cultured fibroblasts, indicating that the signal transduction process probably occurred within the first 30 min of ligand-receptor interaction. Finally, amelioride, an inhibitor of the Na(+)-H+ antiport, was shown to inhibit IL-1 beta-induced GM-CSA in a dose-dependent manner.
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PMID:The role of protein kinase C in interleukin 1 and tumor necrosis factor alpha induction of fibroblasts to produce and release granulocyte-macrophage colony-stimulating activity. 216 34

The marine natural products manoalide and scalaradial are potent anti-inflammatory agents that inactivate the enzyme phospholipase A2 (PLA2) in vitro. To study the mechanism of inhibition of prostaglandin E2 (PGE2) production in human monocytes by manoalide and scalaradial, lipopolysaccharide (LPS)-induced prostaglandin biosynthesis and induction of prostaglandin H synthase (PGHS) were evaluated. LPS (10 ng/mL) and interleukin-1 beta (IL-1 beta, 50-1000 ng/mL) but not tumor necrosis factor alpha (TNF alpha, 300 ng/mL) induced the expression of the PGHS-2 isoform as determined by immunoblot analysis with a specific polyclonal antibody for PGHS-2. Manoalide and scalaradial (1-10 microM) inhibited LPS-induced endogeneous PGE2 production, reduced the LPS-induced PGHS activity, and reduced the expression of PGHS-2. Indomethacin [a PGHS inhibitor (0.01 to 0.1 microM)], zileuton [a 5-lipoxygenase inhibitor (3-10 microM)], and WEB-2806 [a platelet-activating factor (PAF) antagonist (30 microM)] did not affect the LPS-induced expression of PGHS-2 in human monocytes. These results suggest that modulation of lipid mediator production by manoalide or scalaradial may not be involved in the observed effects on the expression of PGHS-2. Manoalide and scalaradial also inhibited the release of IL-1 beta and TNF alpha from LPS-stimulated monocytes. Expression of PGHS-2 induced by either LPS or IL-1 beta was blocked by the IL-1 receptor antagonist (IL-1ra, 2 micrograms/mL) but not by rolipram, a phosphodiesterase IV inhibitor that inhibits TNF alpha but not IL-1 beta release. Similar to LPS, IL-1 beta-induced PGHS-2 expression was apparently not regulated by lipid mediators such as prostaglandins, leukotrienes or PAF as determined with specific inhibitors and antagonists. Scalaradial and to some extent manoalide were capable of blocking the IL-1 beta-induced expression of PHGS-2. These results indicate that IL-1 beta is the predominant cytokine responsible for the induction of PGHS-2 in the human monocyte. Furthermore, marine natural products such as scalaradial have novel effects on the IL-1 beta-mediated induction of PGHS-2 in human monocytes, which appears to be independent of effects on lipid mediator production.
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PMID:Regulation of prostaglandin H synthase 2 expression in human monocytes by the marine natural products manoalide and scalaradial. Novel effects independent of inhibition of lipid mediator production. 757 73

Bacterial endotoxins (lipopolysaccharide or LPS) provoke shock and tissue injury by eliciting the release of toxic factors from reticuloendothelial cells. One of the principal endogenous factors involved in this process is tumor necrosis factor alpha (TNF alpha). In this study, inhibitors selective for different classes of phosphodiesterases (PDE), were examined for their effects on LPS-induced TNF alpha production by human monocytes. The selective cAMP-PDE IV inhibitors, rolipram and RO-20-1724 were capable of inhibiting LPS-induced TNF alpha production by human monocytes in a concentration-dependent manner. Rolipram was used to examine further the cellular pharmacology of PDE IV inhibitors on cytokine production. The IC50 for inhibition of LPS-induced TNF alpha production by rolipram was 0.1 microM, whereas production of IL-1 beta or IL-6 was unaffected. Furthermore, rolipram was equally effective in inhibiting TNF alpha production by a number of other stimuli. Inhibition of TNF alpha production by rolipram was associated with an elevation of intracellular cAMP, consistent with a mechanism involving phosphodiesterase inhibition. Rolipram was efficacious in suppressing LPS-induced TNF alpha mRNA expression, and at the protein level was also active when added to cultures post-stimulated with LPS. This indicates that rolipram may act at both the transcriptional and translational levels. Rolipram inhibited TNF alpha production in vivo in a rat endotoxemia model. Collectively, these data suggest that the prototypic inhibitor of PDE IV isozyme, rolipram, can effectively and selectively inhibit LPS-induced TNF alpha production through elevation of intracellular cAMP.
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PMID:Characterization of cAMP-dependent inhibition of LPS-induced TNF alpha production by rolipram, a specific phosphodiesterase IV (PDE IV) inhibitor. 784 52

Phosphodiesterase inhibitors were used as a tool to manipulate cellular nucleotide levels in vitro and in vivo. The lipopolysaccharide (LPS)-induced release of tumor necrosis factor alpha (TNF-alpha) from mouse peritoneal macrophages was inhibited by prostaglandin E2 with an IC50 of 0.05 microM and by dibutyryl-cAMP with an IC50 of 180 microM. In the presence of the phosphodiesterase inhibitors zardaverine or rolipram the intracellular cAMP concentration of LPS-stimulated macrophages was significantly increased. In these cells, LPS-inducible TNF release was inhibited by zardaverine (IC50 = 1.5 microM) or by rolipram (IC50 = 0.35 microM). In a model of septic shock, i.e. LPS challenge of galactosamine-sensitized mice, a dose-dependent protection against liver injury was observed following oral application of rolipram (ED50 = 0.55 mg/kg) or of zardaverine (ED50 approximately 30 mg/kg). The adenylate cyclase activator forskolin was also protective. Rolipram also protected against TNF-induced liver injury in mice while zardaverine failed to do so. It is concluded that the intracellular cAMP level of macrophages is a critical determinant of LPS-inducible TNF release and therefore modulates the susceptibility to septic shock.
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PMID:Protection by phosphodiesterase inhibitors against endotoxin-induced liver injury in galactosamine-sensitized mice. 839 40

Effects of xanthine derivatives (pentoxifylline, caffeine, theophylline, 1-methyl-3-isobutylxanthine) on P-glycoprotein mediated vincristine resistance of L1210/VCR mouse leukemic cell subline were studied. From the applied xanthines only PTX was found to reverse the vincristine resistance of the above cells. Moreover, only PTX, but not other xanthine, increased the accumulation of [3H]vincristine by L1210/VCR cells. Thus it may be concluded that PTX-induced reversal of vincristine resistance could not be explained from the point of known pharmacological effects of PTX that are common for other xanthines such as inhibition of phosphodiesterase activity, calcium mobilizing effect, inhibition of tumor necrosis factor alpha (TNF), etc.
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PMID:Overcoming of P-glycoprotein mediated vincristine resistance of L1210/VCR mouse leukemic cells could be induced by pentoxifyline but not by theophylline and caffeine. 884 53

We studied the effects of various phosphodiesterase (PDE) III inhibitors: amrinone, pimobendan and vesnarinone: a PDE IV inhibitor (Ro 20-1724) and a PDE V inhibitor (E-4021) on the production of cytokines which have been shown to depress myocardial function. Recently developed inotropic agents which inhibit PDE III activity have produced short-term hemodynamic benefits in patients with advanced heart failure, but long-term treatment with these agents has an adverse effect on survival. However, vesnarinone, which has been shown to improve survival dramatically, has an immunomodulating effect and inhibits the production of cytokines. Peripheral blood mononuclear cells obtained from healthy human subjects were stimulated with lipopolysaccharide and each PDE inhibitor was added. After 24 h of incubation, tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta) and IL-6 in the culture supernatants were measured by an enzyme-linked immunosorbent assay. All three PDE III inhibitors, amrinone, pimobendan and vesnarinone, inhibited TNF-alpha production, but vesnarinone's inhibitory effect was the most prominent. Amrinone and pimobendan enhanced IL-1 beta production, whereas vesnarinone had no effect. Vesnarinone inhibited IL-6 production and pimobendan slightly decreased IL-6 production, whereas amrinone had no significant effect on IL-6 production. The PDE IV inhibitor, Ro 20-1724, decreased the production of IL-1 beta and TNF-alpha and also tended to inhibit IL-6 production; its modulation of cytokine production was similar to the effects of vesnarinone. Because 8Br-cAMP or 8Br-cGMP did not suppress cytokine production, the modulating effects were not considered to result from an increase in cAMP or cGMP. Differential modulation of cytokine production may play a role in the therapeutic effect in heart failure patients who are treated with drugs that have PDE-inhibitory actions. It may be important to study whether the use of dual inhibitors of PDE III and PDE IV is therapeutically more useful for the treatment of heart failure due to their immunomodulating properties.
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PMID:Differential modulation of cytokine production by drugs: implications for therapy in heart failure. 900 65

In cultured rat hepatocytes, the gluconeogenic key enzyme, phosphoenolpyruvate carboxykinase (PCK), is induced by glucagon via elevation of cyclic 3',5' adenosine monophosphate (cAMP). The proinflammatory cytokine, interleukin-6 (IL-6), which in the liver together with IL-1beta and tumor necrosis factor alpha triggers the acute-phase response, had been shown to attenuate the glucagon-induced increase in PCK gene transcription, messenger (mRNA) levels, and enzyme activity. The molecular mechanism of this inhibition was investigated in the present study. Glucagon increased cyclic cAMP and PCK mRNA levels to a transient maximum twofold and fivefold, respectively. The increases were attenuated by IL-6. Forskolin, which stimulates adenylate cyclase activity, increased cAMP and PCK mRNA levels 1.6-fold and fivefold, respectively. However, IL-6 attenuated the forskolin-stimulated increase in PCK mRNA but not the increase in cAMP. This showed that IL-6 inhibited PCK mRNA increase in part by the attenuation of cAMP increase, but also beyond cAMP formation. This was confirmed in experiments in which PCK mRNA levels were increased by the nonhydrolyzable cAMP-analogue, chlorophenylthio (CPT)-cAMP. The increase in PCK mRNA was again attenuated by IL-6. In pertussis toxin- and in isobutylmethylxanthine-treated hepatocytes, IL-6 still inhibited the glucagon-stimulated increase in cAMP, indicating that IL-6 did not activate an inhibitory G-protein or phosphodiesterase, which could cause the impairment of cAMP increase. To demonstrate whether the inhibition of PCK gene expression by IL-6 beyond cAMP might be caused by the inhibition of the activation of the PCK gene promoter by cAMP, cultured rat hepatocytes were transfected with a luciferase reporter gene construct under the control of a PCK gene promoter fragment (base -979 to base +32). Luciferase activity was determined after stimulation of the cells with CPT-cAMP in the absence or presence of IL-6. CPT-cAMP increased luciferase activity by 1.7-fold, which was inhibited in the presence of IL-6. It is concluded that IL-6 had a dual inhibitory effect on the stimulation of PCK gene expression by glucagon. It inhibited the increase in cAMP at a site before cAMP formation by adenylate cyclase and at a site after cAMP formation, the activation of the PCK gene promoter by cAMP.
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PMID:Mechanism of the impairment of the glucagon-stimulated phosphoenolpyruvate carboxykinase gene expression by interleukin-6 in rat hepatocytes: inhibition of the increase in cyclic 3',5' adenosine monophosphate and the downstream cyclic 3',5' adenosine monophosphate action. 921 54

1. The effects of cAMP-phosphodiesterase (PDE) isozyme inhibitors on the production of tumor necrosis factor alpha (TNF-alpha), and interleukins 1 beta 8 (IL-1 beta and IL-8) by lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (PBMC) were evaluated. In addition, we investigated the effects of dibutyryl cAMP (dbcAMP) and beta-adrenergic receptor agonist on the production of these cytokines. 2. Type IV PDE inhibitors were more effective at inhibiting the production of TNF-alpha and IL-1 beta by LPS-stimulated PBMC than a nonselective, type III or type III/IV inhibitor. In contrast, these agents had no effect on IL-8 production. 3. Increasing concentrations of dbcAMP progressively reduced the production of TNF-alpha and IL-1 beta but not IL-8. 4. The addition of beta-agonist increased the inhibitory effect of PDE inhibitors tested on the production of TNF-alpha and IL-1 beta. 5. Type IV PDE inhibitors could be potent pharmacological agents for the treatment of diseases in which TNF-alpha and IL-1 beta are important etiological factors.
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PMID:Effects of cAMP-phosphodiesterase isozyme inhibitor on cytokine production by lipopolysaccharide-stimulated human peripheral blood mononuclear cells. 935 14

The present study has investigated the therapeutic potential of a type 4 phosphodiesterase (PDE) inhibitor, rolipram, in experimental lung injury. Acute lung injury was induced in the mouse by combined treatment with lipopolysaccharide (LPS; 10 mg/kg, i.v.) and zymosan (3 mg/kg, i.v.), and assessed using extravascular albumin accumulation; neutrophil sequestration in pulmonary capillaries was also measured. The results show that pretreatment with rolipram (5 mg/kg, i.p.) was protective against the induction of lung injury by combined LPS and zymosan; extravascular albumin accumulation was reduced by 89% and neutrophil sequestration in lung tissue, as assessed by lung myeloperoxidase (MPO) activity was reduced by 75%. Pretreatment with rolipram also attenuated increases in serum tumor necrosis factor alpha (TNFalpha) levels induced by LPS and zymosan treatment, measured after 2.5 h. The role of endogenous TNFalpha in the induction of lung injury was therefore assessed. Blockade of endogenous TNFalpha by treatment with the soluble receptor p55-IgG fusion protein or an anti-murine TNFalpha monoclonal antibody, TN3. 19.12, had no protective effect against LPS and zymosan-induced lung injury. This suggests that there is a disassociation between TNFalpha production and the induction of injury in this model. Administration of rolipram after LPS and before zymosan treatment obliterated the increase in pulmonary vascular permeability, but its effect on sequestration of neutrophils in pulmonary microvessels, as measured by MPO, was less marked. The results of the present study suggest that use of agents such as rolipram that inhibit PDE4 may have a therapeutic role in treatment of acute lung injury, since we have shown that it is effective in attenuation of neutrophil activation even after sequestration. However, its effect appears to be independent of TNFalpha inhibition.
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PMID:Suppression of acute lung injury in mice by an inhibitor of phosphodiesterase type 4. 949 Jun 59

Exposure of primary rat glial cells to heat inactivated Streptococcus pneumoniae, induced dose-dependent production of tumor necrosis factor alpha (TNF alpha), nitric oxide (NO) and prostaglandin E2 (PGE2). Concomitant addition of the bacterium and the synthetic glucocorticoid dexamethasone resulted in complete suppression of TNF alpha, NO and PGE2 production. Pentoxifylline, a phosphodiesterase inhibitor completely blocked TNF alpha secretion, whereas NO and PGE2 were not affected. Low-molecular-weight heparin enoxaparin caused 25-64% inhibition in TNF alpha production, up to 30% inhibition of NO secretion and a 10% reduction in PGE2. Thus, Streptococcus pneumoniae, the pathogen most commonly associated with meningitis in the Western world can be added to the list of agents causing direct stimulation of glial cells. Pentoxifylline and enoxaparin in addition to dexamethasone may limit the central nervous system local inflammatory responses and could improve the effort towards reducing the dismal outcome of patients with pneumococcal meningitis.
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PMID:Glial cells production of inflammatory mediators induced by Streptococcus pneumoniae: inhibition by pentoxifylline, low-molecular-weight heparin and dexamethasone. 956 17


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