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)

Type 4 phosphodiesterase (PDE4) inhibitors reportedly induce apoptosis in chronic lymphocytic leukemia (CLL) cells. Following clinical improvement of one previously untreated CLL patient with sildenafil therapy, we evaluated the in vitro induction of apoptosis in CLL cells by 4 PDE5/6 inhibitors, including sildenafil, vardenafil, zaprinast, and methoxyquinazoline (MQZ). After 24 hours of culture, the various PDE inhibitors differed in their ability to induce apoptosis, with zaprinast displaying no killing effect. Normal B cells isolated from control donors were totally resistant to PDE-induced apoptosis. Vardenafil was 3 and 30 times more potent an inducer of apoptosis than sildenafil and MQZ, respectively. Both vardenafil and sildenafil failed to elevate adenosine 3'5' cyclic monophosphate (cAMP) levels, largely excluding an inhibitory effect on cAMP-PDE3, -PDE4, and -PDE7. Vardenafil- or sildenafil-treated B-CLL cells displayed up to 30% intracellular active caspase 3. Drug-induced apoptosis was inhibited by the caspase inhibitor z-VAD.fmk, prevented by interleukin-4 (IL-4), and significantly reduced by stromal-derived factor1-alpha (SDF-1alpha). We conclude that vardenafil and sildenafil induce caspase-dependent apoptosis of B-CLL cells in vitro and thus might be considered in the treatment of CLL patients. However, further in vivo investigations should be warranted.
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PMID:Sildenafil and vardenafil, types 5 and 6 phosphodiesterase inhibitors, induce caspase-dependent apoptosis of B-chronic lymphocytic leukemia cells. 1239 51

Modalities that induce specific differentiation to T cell memory in immune responses are important for vaccine design, but there is a paucity of well characterized molecular pathways useful to target for this purpose. We have shown previously that pentoxifylline (PF), a phosphodiesterase (PDE) inhibitor in common clinical use, enhances the commitment of in vitro allo-primed human T cells to secondary responsiveness, a characteristic crucial for memory T cells, which are key determinants of the longevity of the immune response. We now show that this effect can also be mediated by activation of adenylate cyclase (AC) and involves PDE4, but not PDE3 or PDE7. PF-mediated enhancement of T-cell priming is inhibited by blocking AC, is specifically signaled via cAMP-dependent protein kinase A (PKA) isoform I, and is probably independent of both nuclear factor-kappaB and the mitogen-activated protein kinase cascade. Furthermore, known pharmacological inhibitors of AC or PKA by themselves cannot block T-cell priming in the absence of PF or rolipram (Rm), and enhancement of priming requires the presence of PF only relatively late during a 4-day priming in vitro (at 48-96 h), suggesting that pharmacological extension of cAMP-mediated signaling can bring about an event critical for T cell commitment to memory. Furthermore, PF and Rm prevent induction of caspase activation and apoptosis in anti-CD3-activated human T cells. Together, our data suggest that PKA-I-mediated signals triggered by prolonging the half-life of cAMP induced during T-cell priming increase survival of activated T cells and enhance memory T cell commitment.
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PMID:Commitment of activated T cells to secondary responsiveness is enhanced by signals mediated by cAMP-dependent protein kinase A-I. 1243 16

To understand changes in cyclic nucleotide metabolism in muscle disease states, the expression of phosphodiesterase (PDE) isozymes in normal mouse leg muscle was examined. Four subcellular fractions were generated by differential centrifugation at 10,000 x g and 100,000 x g. cAMP PDE activity was found predominately in the soluble fractions, while cGMP PDE activity was more evenly distributed amongst soluble and particulate fractions. Pharmacological inhibitors demonstrate that PDE4 represents the major cAMP hydrolyzing activity and PDE2 represents the major cGMP hydrolyzing activity in mouse leg muscle. PDE1 is expressed at low levels, while PDE3 and PDE5 are intermediate. Between 20 and 40% of total PDE activity remained in the presence of inhibitors for PDE1-PDE5, indicating that other PDE families contribute to the total PDE pool. Reverse-transcription PCR with family-specific primers showed expression of mRNA for PDE7-PDE9, supporting this conclusion. Total PDE activity was found to be elevated in tissue extracts from a mouse model of Duchenne's muscular dystrophy.
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PMID:Cyclic nucleotide phosphodiesterase isozymes expressed in mouse skeletal muscle. 1256 38

Selective inhibitors against the 11 families of cyclic nucleotide phosphodiesterases (PDEs) are used to treat various human diseases. How the inhibitors selectively bind the conserved PDE catalytic domains is unknown. The crystal structures of the PDE4D2 catalytic domain in complex with (R)- or (R,S)-rolipram suggest that inhibitor selectivity is determined by the chemical nature of amino acids and subtle conformational changes of the binding pockets. The conformational states of Gln369 in PDE4D2 may play a key role in inhibitor recognition. The corresponding Y329S mutation in PDE7 may lead to loss of the hydrogen bonds between rolipram and Gln369 and is thus a possible reason explaining PDE7's insensitivity to rolipram inhibition. Docking of the PDE5 inhibitor sildenafil into the PDE4 catalytic pocket further helps understand inhibitor selectivity.
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PMID:Three-dimensional structures of PDE4D in complex with roliprams and implication on inhibitor selectivity. 1284 49

The biochemical and pharmacological characteristics in human proinflammatory cells of BRL 50481 [3-(N,N-dimethylsulfonamido)-4-methyl-nitrobenzene], a novel and selective inhibitor of phosphodiesterase (PDE) 7, are described. BRL 50481 inhibited the activity of hrPDE7A1 expressed in baculovirus-infected Spodoptera frugiperda 9 cells in a competitive manner (Ki value of 180 nM) and was 416 and 1884 times less potent against PDE3 and 38 and 238 times less potent against PDE4 at a substrate concentration of 1 microM and 50 nM cAMP, respectively. Western blotting identified HSPDE7A1 but not HSPDE7A2 in three human cell types that are implicated in the pathogenesis of chronic obstructive lung disease, namely, CD8+ T-lymphocytes, monocytes, and lung macrophages. BRL 50481 had no effect on the proliferation of CD8+ T-lymphocytes and only marginally (approximately 2-11%) reduced the generation of tumor necrosis factor (TNF)alpha from blood monocytes and lung macrophages. However, in the presence of BRL 50481 the inhibitory effect of rolipram was enhanced on all three cell types. The expression of HSPDE7A1 was increased in a time-dependent manner in monocytes that were "aged" in culture medium. Under this condition, BRL 50481 now inhibited TNFalpha generation in a concentration-dependent manner. In aged monocytes, rolipram, Org 9935 (a PDE3 inhibitor), and prostaglandin E2 inhibited TNFalpha generation in a concentration-dependent manner and interacted additively with BRL 50481. BRL 50481 is the first fully documented PDE7 inhibitor that has acceptable selectivity for in vitro studies. Furthermore, although BRL 50481 had only a modest inhibitory effect per se on the proinflammatory cells studied, it acted at least additively with other cAMP-elevating drugs, especially when HSPDE7A1 was up-regulated.
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PMID:Discovery of BRL 50481 [3-(N,N-dimethylsulfonamido)-4-methyl-nitrobenzene], a selective inhibitor of phosphodiesterase 7: in vitro studies in human monocytes, lung macrophages, and CD8+ T-lymphocytes. 1537 56

The cAMP protein kinase A (PKA) pathway in T cells conveys an inhibitory signal to suppress inflammation. This study was performed to understand the mechanisms involved in cAMP-mediated signaling in T lymphocytes. A-kinase anchoring proteins (AKAPs) bind and target PKA to various subcellular locations. AKAPs also bind other signaling molecules such as cyclic nucleotide phosphodiesterases (PDEs) that hydrolyze cAMP in the cell. PDE4 and PDE7 have important roles in T cell activation. Based on this information, we hypothesized that AKAPs associate with PDEs in T lymphocytes. Immunoprecipitation of Jurkat cell lysates with Abs against both the regulatory subunit of PKA (RIIalpha) and specific AKAPs resulted in increased PDE activity associated with RIIalpha and AKAP95, AKAP149, and myeloid translocation gene (MTG) compared with control (IgG). Immunoprecipitation and pull-down analyses demonstrate that PDE4A binds to AKAP149, AKAP95, and MTG, but not AKAP79, whereas PDE7A was found to bind only MTG. Further analysis of MTG/PDE association illustrated that PDE4A and PDE7A bind residues 1-344 of MTG16b. Confocal analysis of HuT 78 cells stained with anti-PDE7A showed overlapping staining patterns with the Golgi marker GM130, suggesting that PDE7A is located in the Golgi. The staining pattern of PDE7A also showed similarity to the staining pattern of MTG, supporting the immunoprecipitation data and suggesting that MTG may interact with PDE7A in the Golgi. In summary, these data suggest that AKAPs interact with both PKA and PDE in T lymphocytes and thus are a key component of the signaling complex regulating T cell activation.
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PMID:A-kinase anchoring proteins interact with phosphodiesterases in T lymphocyte cell lines. 1547 20

Cyclic nucleotide levels are controlled through their synthesis from nucleotide triphosphates by cyclases and their degradation to 5'-monophosphates by phosphodiesterases (PDEs). Components controlling cyclic AMP-induced relaxation in the urinary tract include receptors, inhibitory and stimulatory G-proteins, isoforms of adenylyl cyclase and PDEs. The responsiveness of PDEs to a variety of physiological challenges is related to the presence of multiple families of isoenzymes with specific localization within tissues and within cells. At least 11 families of PDEs encode more than 50 PDE proteins produced in mammalian cells. In the urinary tract, characterization of PDE isoforms has lagged behind other systems and much of the literature was published prior to identification of PDE7, 8, 9, 10, 11. Specific PDE inhibitors regulate smooth muscle function in the bladder, urethra, prostate and ureter. The pharmacological potential of these inhibitors may include treatment of urge incontinence and the low compliance bladder, and treatment of prostate cancer. G-proteins also regulate cyclic AMP production. Changes in specific G- protein isoforms with aging, most prominently Gialpha2, cause decreased relaxation response in the aging bladder. As we have seen here with aging and certainly in other disease processes, levels of the components of adenylyl cyclase/phosphodiesterase/protein kinase can change and thus affect the relaxation response. By exploitation of differences in PDE expression in disease, such as the overexpression of PDEs in cancer, treatment options may present themselves.
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PMID:Regulation of cyclic nucleotides in the urinary tract. 1585 36

Despite reports of the efficacy of phosphodiesterase 4 (PDE4) inhibitors in some Phase III clinical trials of asthma and chronic obstructive pulmonary disease, the presence of dose-limiting side effects continue to hamper their development. Consequently, new approaches are required to improve the therapeutic ratio and the safety of these compounds. One option might lie in the synthesis of small molecules with a broader PDE specificity. The development of dual-specificity compounds that inhibit PDE4 and PDE1, PDE3, PDE5 or PDE7 could be beneficial for the treatment of chronic inflammatory lung diseases and are currently being investigated.
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PMID:Life after PDE4: overcoming adverse events with dual-specificity phosphodiesterase inhibitors. 1590 9

The regulation of the secondary messengers, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), is crucial in the hormonal regulation of bone metabolism. Both cAMP and cGMP are inactivated by cyclic nucleotide phosphodiesterases (PDEs), a superfamily of enzymes divided into 11 families (PDE1-11). We compared the PDEs of cultured human osteoblasts (NHOst) and SaOS-2 osteosarcoma cells. The PDE activity of NHOst cells consisted of PDE1, PDE3 and PDE7, whereas PDE1, PDE7 and PDE4, but no PDE3 activity was detected in SaOS-2 cells. In line with the difference in the PDE profiles, rolipram, a PDE4 inhibitor, increased the accumulation of cAMP in SaOS-2, but not in NHOst cells. Expression of PDE subtypes PDE1C, PDE3A, PDE4A, PDE4B, PDE7A and PDE7B was detected in both cell types. NHOst cells additionally expressed PDE1A.
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PMID:Cyclic nucleotide phosphodiesterases (PDEs) in human osteoblastic cells; the effect of PDE inhibition on cAMP accumulation. 1601 Feb 95

Cyclic nucleotide phosphodiesterases (PDEs), which are ubiquitously distributed in mammalian tissues, play a major role in cell signaling by hydrolyzing cAMP and cGMP. Due to their diversity, which allows specific distribution at cellular and subcellular levels, PDEs can selectively regulate various cellular functions. Their critical role in intracellular signaling has recently designated them as new therapeutic targets for inflammation. The PDE superfamily represents 11 gene families (PDE1 to PDE11). Each family encompasses 1 to 4 distinct genes, to give more than 20 genes in mammals encoding the more than 50 different PDE proteins probably produced in mammalian cells. Although PDE1 to PDE6 were the first well-characterized isoforms because of their predominance in various tissues and cells, their specific contribution to tissue function and their regulation in pathophysiology remain open research fields. This concerns particularly the newly discovered families, PDE7 to PDE11, for which roles are not yet established. In many pathologies, such as inflammation, neurodegeneration, and cancer, alterations in intracellular signaling related to PDE deregulation may explain the difficulties observed in the prevention and treatment of these pathologies. By inhibiting specifically the up-regulated PDE isozyme(s) with newly synthesized potent and isozyme-selective PDE inhibitors, it may be potentially possible to restore normal intracellular signaling selectively, providing therapy with reduced adverse effects.
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PMID:Cyclic nucleotide phosphodiesterase (PDE) superfamily: a new target for the development of specific therapeutic agents. 1610 38


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