Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Cyclic AMP (cAMP) is a key second messenger in all cells. It is compartmentalized within cells and its levels are controlled, as a result of spatially discrete signaling cassettes controlling its generation, detection and degradation. Underpinning compartmentalized cAMP signaling are approximately 20 members of the phosphodiesterase-4 (PDE4) family. The selective inhibition of this family generates profound, functional effects and PDE4 inhibitors are currently under development to provide potential, novel therapeutics for the treatment of inflammatory diseases, such as asthma, chronic obstructive pulmonary disease and psoriasis, as well as treating depression and serving as cognitive enhancers. Here, we delineate the range of PDE4 isoforms, their role in signaling, their structural biology and related preclinical and clinical pharmacology.
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PMID:Keynote review: phosphodiesterase-4 as a therapeutic target. 1625 73

Arginase is greatly elevated in asthma and is thought to play a role in the pathophysiology of this disease. As inhibitors of phosphodiesterase 4 (PDE4), the predominant PDE in macrophages, elevate cAMP levels and reduce inflammation, they have been proposed for use in treatment of asthma and chronic obstructive pulmonary disease. As cAMP is an inducer of arginase, we tested the hypothesis that a PDE4 inhibitor would enhance macrophage arginase induction by key cytokines implicated in asthma and other pulmonary diseases. RAW 264.7 cells were stimulated with IL-4 or transforming growth factor (TGF)-beta, with and without the PDE4 inhibitor rolipram. IL-4 and TGF-beta increased arginase activity 16- and 5-fold, respectively. Rolipram alone had no effect but when combined with IL-4 and TGF-beta synergistically enhanced arginase activity by an additional 15- and 5-fold, respectively. The increases in arginase I protein and mRNA levels mirrored increases in arginase activity. Induction of arginase II mRNA was also enhanced by rolipram but to a much lesser extent than arginase I. Unlike its effect in RAW 264.7 cells, IL-4 alone did not increase arginase activity in human alveolar macrophages (AM) from healthy volunteers. However, combining IL-4 with agents to induce cAMP levels induced arginase activity in human AM significantly above the level obtained with cAMP-inducing agents alone. In conclusion, agents that elevate cAMP significantly enhance induction of arginase by cytokines. Therefore, consequences of increased arginase expression should be evaluated whenever PDE inhibitors are proposed for treatment of inflammatory disorders in which IL-4 and/or TGF-beta predominate.
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PMID:Inhibition of phosphodiesterase 4 amplifies cytokine-dependent induction of arginase in macrophages. 1625 97

Abundant data from animal models and humans support the hypothesis that changes at the level of parasympathetic neuronal control of airway smooth muscle result in increased bronchoconstriction in response to vagal stimulation, leading to airway hyperresponsiveness. Neuronal inhibitory M2 muscarinic acetylcholine receptors on parasympathetic nerves are responsible for limiting acetylcholine release from these nerves. In humans with asthma, and after pulmonary inflammatory events in experimental animals, these receptors are dysfunctional, which results in airway hyperresponsiveness. Although it is unknown what mechanisms underlie airway hyperresponsiveness in chronic obstructive pulmonary disease, loss of parasympathetic control of airway smooth muscle is thought to be a contributing mechanism. As such, anticholinergic therapy is used extensively and with a high degree of success in the treatment of this condition. The future for inhaled anticholinergic compounds for the treatment of chronic obstructive pulmonary disease appears to rest in their combination with other agents, such as beta2 agonists and phosphodiesterase-4 inhibitors. Nonselective anticholinergic agents might be the best choice, because M2 muscarinic receptors on airway smooth muscle inhibit the generation and accumulation of cyclic adenosine monophosphate. Adequate concurrent blockade of M3 muscarinic receptors would be expected to counteract the enhanced acetylcholine release that would result from blockade of neuronal inhibitory M2 muscarinic receptors.
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PMID:Cholinergic pathways in the lungs and anticholinergic therapy for chronic obstructive pulmonary disease. 1626 52

Phosphodiesterase-4 isoenzymes have absolute specificity for cyclic adenosine-3',5'-monophosphate and are considered potential therapeutic targets for the treatment of chronic inflammatory disorders, such as chronic obstructive pulmonary disease, with small-molecule inhibitors. Several selective phosphodiesterase-4 inhibitors are in clinical trials of chronic obstructive pulmonary disease, including cilomilast and roflumilast. Despite some encouraging data from phase III clinical trials, the current generation of phosphodiesterase-4 inhibitors is hampered by a low therapeutic ratio. Indeed, a major obstacle is their propensity to evoke non-steroid-like side effects, of which nausea, diarrhea, abdominal pain, vomiting, and dyspepsia are the most common. In addition, a particularly worrying potential toxicity of phosphodiesterase-4 inhibitors, also shared by phosphodiesterase-3 inhibitors and other vasodilators, is arteritis/periarteritis. One potential means of improving the therapeutic ratio and safety of phosphodiesterase-4 inhibitors may lie in the development of compounds that have broader phosphodiesterase specificity. Of the 11 phosphodiesterase families that have been unequivocally identified, dual-specificity compounds that inhibit phosphodiesterase-4 and phosphodiesterase-1, phosphodiesterase-3, or phosphodiesterase-7 may offer the best opportunities to enhance clinical efficacy.
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PMID:Phosphodiesterase-4: selective and dual-specificity inhibitors for the therapy of chronic obstructive pulmonary disease. 1626 57

Although theophylline has side effects when used in bronchodilator doses, increasing evidence shows that it has significant antiinflammatory effects in chronic obstructive pulmonary disease at lower plasma concentrations. These antiinflammatory effects are unlikely to be accounted for by phosphodiesterase inhibition or adenosine receptor antagonism, which require higher concentrations. There is now evidence that theophylline at low therapeutic concentrations is an activator of histone deacetylases and that this activation enhances the antiinflammatory effect of corticosteroids. There appears to be a marked reduction in histone deacetylase-2 in macrophages and peripheral lung of patients with chronic obstructive pulmonary disease, which accounts for amplified inflammation and steroid resistance. Theophylline has been shown to restore steroid sensitivity in vitro. The effect of theophylline on histone deacetylase activity appears to be enhanced by oxidative stress. The mechanism whereby theophylline activates histone deacetylase is not yet known, but it does not involve other known actions of theophylline that account for its side effects. Better understanding of the molecular basis for the action of theophylline might lead to the development of novel drugs.
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PMID:Theophylline in chronic obstructive pulmonary disease: new horizons. 1626 58

Pulmonary hypertension (PH) is an important predictor of mortality in chronic obstructive pulmonary disease (COPD). The phosphodiesterase 5 inhibitor sildenafil has been demonstrated to reduce pulmonary arterial pressure (PAP) in different diseases. We wanted to investigate the effect of sildenafil on hemodynamic parameters and the 6-min walk test (6 MWT) in six patients with severe COPD and echocardiographically estimated PH. A 6 MWT was performed and hemodynamic parameters were measured by right heart catheterization before and 1 and 12h after injection of 50mg sildenafil intravenously. A 3-months period of peroral sildenafil therapy 50mg twice daily followed and finally hemodynamic parameters and a 6 MWT were repeated. Intravenously applied sildenafil could be demonstrated to reduce PAP and pulmonary vasculature resistance (PVR) significantly. And after 3 months of oral sildenafil, the mean PAP has decreased from 30.2+/-5.5 mmHg (range: 24-39 mmHg) to 24.6+/-4.2 mmHg (range: 20-30 mmHg) (p=0.01). The PVR has decreased from 401+/-108 dyn s cm(-5) (range: 266-558 dyn s cm(-5)) to 264+/-52 dyn s cm(-5) (range: 204-333 dyn s cm(-5)) (p<0.05). Physical conditions improved: the 6-min walk distance increased from 351+/-49 to 433+/-52 m. In conclusion, in six patients suffering from severe COPD we could demonstrate significantly improved hemodynamic parameters after 50 mg sildenafil intravenous application. And after 3 months of oral sildenafil, walking distance in the 6 MWT increased significantly as well as hemodynamic parameters in the five patients who had accepted a second right heart catheterization.
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PMID:Sildenafil improves hemodynamic parameters in COPD--an investigation of six patients. 1629 3

Roflumilast is an inhibitor of phosphodiesterase- IV (PDE4), a cellular enzyme that is linked to airway inflammation in asthma and chronic obstructive pulmonary disease (COPD). In clinical trials, roflumilast produced significant improvements in FEV1 (forced expiratory volume in one second) and PEF (peak expiratory flow) compared with low-dose inhaled beclomethasone in asthma patients, and compared with placebo in COPD patients. Roflumilast reduced the use of rescue medication in both populations. COPD patients on roflumilast experienced fewer exacerbations. The most common adverse effects reported in roflumilast trials were diarrhea, nausea, headache, and abdominal pain. Evidence is only available in non-peer-reviewed format abstracts. Most of the measures used are markers of clinical effects as opposed to clinical outcomes. More studies are needed to determine the role of roflumilast in the treatment of asthma and COPD.
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PMID:Roflumilast for asthma and chronic obstructive pulmonary disease. 1631 27

Hypoxic pulmonary hypertension (HPH) develops in many patients with advanced chronic obstructive pulmonary disease (COPD) and aggravates their quality of life and prognosis. The most proper but as yet not satisfactory management of HPH involves COPD prophylaxis. In this article pathophysiological background to use systemic vasodilators in treatment of HPH are described, and hemodynamical and clinical results of short and long term trials are discussed. Authors explain lack of clinical benefits with currently used systematic vasodilators in HPH and indicate promising preliminary results with 5-phosphodiesterase inhibitors. The substantial role of chronic oxygen therapy and pulmonary rehabilitation in management of HPH is emphasized.
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PMID:[How to manage the patients with hypoxic pulmonary hypertension?]. 1637 28

Roflumilast is a selective phosphodiesterase (PDE) 4 inhibitor with a range of anti-inflammatory properties and potential for treatment of inflammatory disease. The therapeutic effects of roflumilast are thought to be mediated via increased levels of cellular 3',5'-cyclic adenosine monophosphate (cAMP) and include inhibition of microvascular leakage, inhibition of trafficking, release of cytokines and chemokines from inflammatory cells, and bronchodilation. The anti-inflammatory and bronchodilator properties of roflumilast have resulted in clinical studies to investigate the effects of roflumilast in inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease. In asthma, roflumilast taken as a once-daily oral dose of 500 ug has been shown to improve clinical symptoms and airway function, reduce exercise-induced asthma and decrease bronchial airway hyperresponsiveness. In chronic obstructive pulmonary disease, roflumilast taken as a once-daily oral dose of 500 ug has been shown to reduce the frequency of exacerbations with small effects on improving lung function. Side effects of roflumilast appear to be mild and short lasting. It is likely that this new class of selective PDE4 inhibitor may provide a therapeutic option for patients with inflammatory airway disease.
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PMID:Roflumilast: a selective phosphodiesterase 4 inhibitor. 1638 9

In inflammatory cells, the low K(m) cyclic adenosine monophosphate (cAMP)-specific phosphodiesterase (PDE) 4 subtype is predominant in terms of expression and function, although more recently it has been suggested that PDE 7 may also play a role in regulating inflammatory cell activity. In the present study, PDE 4 and PDE 7 subtype messenger ribonucleic acid (mRNA) transcripts in CD4 and CD8 lymphocytes from healthy (n=10) and asthmatic (n=10) subjects and polymorphonuclear neutrophils (PMNs) and CD8 lymphocytes obtained from healthy (n=10) and chronic obstructive pulmonary disease (COPD) (n=7) subjects were identified and quantified. PDE 4A, PDE 4B, PDE 4D and PDE 7A mRNA were present in similar quantities in both CD4 and CD8 lymphocytes obtained from healthy and asthmatic subjects and in CD8 lymphocytes obtained from healthy and COPD subjects. Expression of PDE 4C and PDE 7B mRNA was also observed, although transcript levels were low and variable between individuals. In addition, the effects of selective PDE 7 inhibition on both phytohaemagluttinin (PHA)-induced human peripheral blood mixed mononuclear cell (HPBMNC) proliferation and fMLP-induced neutrophil elastase (NE) release were studied. HPBMNC and human neutrophils, isolated from the venous blood of healthy volunteers (n=6) were treated with either a novel selective PDE 7 inhibitor PF 0332040 alone or in combination with rolipram. Proliferation of HPBMNC was stimulated by PHA (2microgml(-1)) and assessed by [(3)H]-thymidine incorporation, while fMLP-induced (100nM) NE release was determined using a chromogenic substrate. Both rolipram (0.003-10microM) and PF 0332040 (0.003-10microM) significantly inhibited PHA-stimulated proliferation of HPBMNC ((**)P<0.01). Co-administration of rolipram (0.3-10microM) and PF 0332040 (0.003-10microM) significantly increased the degree of inhibition observed, compared to when either drug was administered alone ((**)P<0.01). PF 0332040 (0.003-10microM) had no inhibitory effect on NE release from human peripheral blood neutrophils stimulated with fMLP (100nM), while rolipram (0.003-10microM) significantly inhibited neutrophil degranulation ((**)P<0.01). These findings suggest no evidence of altered PDE 4 or PDE 7 mRNA transcript levels in inflammatory cells isolated from the peripheral venous blood of mild asymptomatic asthmatic subjects or stable COPD subjects, however, inhibition of PDE 7 may influence mononuclear cell function.
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PMID:Phosphodiesterase (PDE) 7 in inflammatory cells from patients with asthma and COPD. 1642 96


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