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)

We have identified a novel human isozyme of 3',5'-cyclic nucleotide phosphodiesterase (PDE), which we designated PDE8B. cDNA of 2844 bp encoding the C-terminal 659 amino acids of PDE8B was cloned following the identification of an expressed sequence tag (EST) obtained through a search of the EST database. The predicted protein sequences of PDE8B showed highest homology (65% identity, 83% similarity) to that of PDE8A. Northern blot analysis indicated that the mRNA encoding PDE8B is expressed specifically and abundantly in thyroid gland as a approximately 4.2 kb mRNA, in contrast to the wide expression of PDE8A mRNA in various tissues. The carboxyl-terminal 584 amino acids of PDE8B were expressed in E.coli as a fusion protein. The recombinant PDE8B exhibited cAMP PDE activity which was not inhibited by various PDE inhibitors including vinpocetine, milrinone, rolipram, and IBMX with the exception of dipyridamole which caused 50% inhibition at a concentration of 40 microM. cAMP hydrolytic activity was unaffected by cGMP and no cGMP PDE hydrolysis were detectable at concentrations up to 100 microM. These findings suggest that PDE8B is a new member of the PDE8 family.
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PMID:Molecular cloning and characterization of human PDE8B, a novel thyroid-specific isozyme of 3',5'-cyclic nucleotide phosphodiesterase. 978 18

Based on the increasing knowledge of intracellular signal propagation in cavernous smooth muscle tone regulation, which is of major importance to the understanding of both the physiology of erection and the pathophysiology of erectile dysfunction, selective phosphodiesterase (PDE) inhibitors have recently been introduced in the treatment of erectile dysfunction. The first promising clinical data on the use of the orally active PDE5 inhibitor Sildenafil in the treatment of erectile dysfunction were accompanied by boosting research activities on cavernous intracellular signal transduction and phosphodiesterase characterization with the aid of molecular biology and protein chemistry. The presence of mRNA transcripts specific for 14 different human phosphodiesterase isoenzymes and isoforms in human cavernous tissue was shown by RT-PCR: Three isogenes of PDEI, PDE2A and 10A, which hydrolyse cAMP as well as cGMP, the cAMP-specific PDE3A, four isogenes of PDE4, PDE7A and PDE8A, as well as cGMP-specific PDEs PDE5A and PDE9A. Using anion exchange chromatography, the activities of PDE isoenzymes 2, 3, 4, and 5 were detected in cytosolic supernatants of human cavernous smooth muscle. To date, the efficacy and safety of several next generation PDE5 inhibitors for use in the treatment of male erectile dysfunction are under evaluation in vitro and in vivo. Further research will possibly allow identification of diagnostic tools for erectile dysfunction and of even more selective drugs in its therapy.
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PMID:Phosphodiesterase isoenzymes as pharmacological targets in the treatment of male erectile dysfunction. 1128 65

We have cloned cDNAs representing five full-length human phosphodiesterase (PDE) 8A splice variants (PDE8As 1-5) from testis and T cells. PDE8A1 encodes a hydrophilic protein of 829 amino acids, containing an N-terminal REC domain, a PAS domain, and a C-terminal catalytic domain. PDE8A2 encodes a protein of 783 amino acids, identical to PDE8A1 but lacking the PAS domain. PDE8A3 encodes a shorter protein equivalent to the C-terminal 449 amino acids of PDE8A1, containing the catalytic but not the REC and PAS domains. PDE8A4 and PDE8A5, though different from each other at the nucleotide level, encode an identical protein equivalent to the C-terminal 582 amino acids of PDE8A1, including half of the PAS domain. The PDE8A gene is revealed to contain 23 exons, and its exon-intron boundaries have been defined. In addition, we have mapped a common transcription initiation site, and further determined the upstream 5'-flanking sequence of 1740 bp containing the putative promoter. Compared to PDE8A1, PDE8As 2-5 appear to be expressed in much lower abundance. Among various tissues and organs, PDE8A1 and PDE8A2 are expressed at various levels.
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PMID:Human phosphodiesterase 8A splice variants: cloning, gene organization, and tissue distribution. 1173 32

Cyclic adenosine monophosphate (cAMP) is an important second messenger in the hormonal regulation of bone metabolism. cAMP is inactivated by the cyclic nucleotide phosphodiesterases (PDEs), a superfamily of enzymes divided into 11 known families, designated PDE1-11. Interference with the cAMP signaling pathway has been suggested as one mechanism causing glucocorticoid induced osteoporosis. We speculated that glucocorticoids could affect the cAMP pathway by a down-regulation of PDE-mediated cAMP hydrolysis. The main cAMP hydrolysing enzyme families of human MG-63 and SaOS-2 osteosarcoma cells were identified as PDE1 and PDE4 by assaying the PDE activity of Q-sepharose fractions and cell homogenates with selective inhibitors. Treatment with the glucocorticoid dexamethasone (Dex) decreased cAMP-PDE activity by up to 50%, without affecting cGMP-PDE activity. Dex treatment reduced the sensitivity of the total cAMP-PDE activity towards the PDE4 selective PDE inhibitor rolipram. Forskolin stimulated cAMP accumulation was increased 30-60-fold in the presence of rolipram. Treatment with Dex did not affect the basal or forskolin stimulated cAMP accumulation, but treatment resulted in a reduced effect of rolipram on cAMP accumulation. Expression of the following cAMP-PDE subtypes were detected by reverse transcriptase PCR (RT-PCR): PDE1A, PDE1C, PDE2A, PDE3A, PDE4A, PDE4B, PDE4C, PDE4D, PDE7A, PDE7B, PDE8A, PDE10A and PDE11A. Using semi-quantitative RT-PCR, we detected a 50-70% decrease in the mRNA of PDE4A and PDE4B subtypes following Dex treatment. Further analysis revealed that Dex reduced the PDE4A4 and PDE4B1 isoforms. PDE4A1 PDE4A, PDE4A7, PDE4A10, PDE4B2 were also expressed, but Dex did not affect the transcription of these isoforms. We conclude that Dex treatment could affect the cAMP signaling pathway of human osteosarcoma cells by reducing type 4 cAMP-phosphodiesterase (PDE4).
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PMID:Dexamethasone down-regulates cAMP-phosphodiesterase in human osteosarcoma cells. 1562 79

Leydig cells produce testosterone in the testes under the pulsatile control of pituitary luteinizing hormone (LH). cAMP is the intracellular messenger for LH action on steroidogenesis, and pharmacological evidence indicates that the response to LH can be modulated by cyclic nucleotide phosphodiesterases (PDEs). However the types and roles of the PDEs present in Leydig cells have not been fully defined. We report here that PDE8A is expressed in Leydig cells, and using PDE8A knockout mice we provide evidence that PDE8A is a key regulator of LH signaling and steroidogenesis. A 4-fold increase in the sensitivity to LH for testosterone production was detected in Leydig cells isolated from PDE8A knockout mice. In Leydig cells from wild-type mice, 3-isobutyl-1-methylxanthine, a compound that inhibits all cAMP PDEs except PDE8A, elicited only a small increase in the sensitivity of testosterone production to LH. However, in the PDE8-null mice, the effect of this inhibitor is much more pronounced. These observations indicate that PDE8A and at least one other PDE control the same or a complementary pool of cAMP that mediates LH-regulated steroidogenesis. Overall, these results suggest that pharmacological manipulation of PDE8A, alone or in combination with other PDEs present in Leydig cells, may be exploited to modulate testosterone synthesis and possibly to treat various conditions where the local levels of this androgen need to be altered.
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PMID:Modulation of Leydig cell function by cyclic nucleotide phosphodiesterase 8A. 1717 43

Cyclic nucleotide phosphodiesterases (PDEs) comprise a superfamily of enzymes that serve as drug targets in many human diseases. There is a continuing need to identify high-specificity inhibitors that affect individual PDE families or even subtypes within a single family. The authors describe a fission yeast-based high-throughput screen to detect inhibitors of heterologously expressed adenosine 3',5'-cyclic monophosphate (cAMP) PDEs. The utility of this system is demonstrated by the construction and characterization of strains that express mammalian PDE2A, PDE4A, PDE4B, and PDE8A and respond appropriately to known PDE2A and PDE4 inhibitors. High-throughput screens of 2 bioactive compound libraries for PDE inhibitors using strains expressing PDE2A, PDE4A, PDE4B, and the yeast PDE Cgs2 identified known PDE inhibitors and members of compound classes associated with PDE inhibition. The authors verified that the furanocoumarin imperatorin is a PDE4 inhibitor based on its ability to produce a PDE4-specific elevation of cAMP levels. This platform can be used to identify PDE activators, as well as genes encoding PDE regulators, which could serve as targets for future drug screens.
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PMID:Development of a fission yeast-based high-throughput screen to identify chemical regulators of cAMP phosphodiesterases. 1822 26

The second messenger molecule cyclic adenosine monophosphate (cAMP) plays an important role in the hormonal regulation of bone metabolism. cAMP is inactivated by the cyclic nucleotide phosphodiesterases (PDEs), a superfamily of enzymes divided into 11 known families designated PDE 1-11. The aim of this study was to investigate the effect of PDE7 and PDE8 inhibition on the gene expression and differentiation of human osteoblasts. Osteoblasts differentiated from human mesenchymal stem cells (hMSC) were cultured and treated with short interfering RNAs (siRNAs) generated from PDE7 and PDE8 PCR products. Total RNA was isolated from the cells, and gene expression was assayed with cDNA microarray and quantitative real-time PCR. bALP measurements were assayed during differentiation, and mineralization was determined by quantitative Alizarin red S staining. PDE7 and PDE8 inhibition by RNA interference decreased the gene expression of PDE7A by 60-70%, PDE7B by 40-50%, and PDE8A by 30%. PDE7 silencing increased the expression of beta-catenin, osteocalcin, caspase-8, and cAMP-responsive element-binding protein 5 (CREB-5) genes and decreased the expression of the 1, 25-dihydroxyvitamin D3 receptor gene. PDE8A silencing increased the expression of anti-apoptotic genes, but decreased the expression of osteoglycin (osteoinductive factor) and bone morphogenetic protein 1 (BMP-1). PDE7 silencing increased bALP and mineralization up to three-fold compared to controls. Treatment with the PDE7-selective PDE inhibitor BRL-50481 had similar effects on mineralization as the gene silencing. The PDE7 silencing also increased forskolin stimulated cAMP response, but had no effect on the proliferation rate. Furthermore, osteocalcin expression was increased by PDE7 silencing by a mechanism dependent on protein kinase A. Our results show that specific gene silencing with the RNAi method is a useful tool for inhibiting the gene expression of specific PDEs and that PDE7 silencing upregulates several osteogenic genes and increases mineralization. PDE7 may play an important role in the regulation of osteoblastic differentiation.
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PMID:Effects of phosphodiesterase 7 inhibition by RNA interference on the gene expression and differentiation of human mesenchymal stem cell-derived osteoblasts. 1842 Apr 79

The phosphodiesterase (PDE) family is a group of enzymes that catalyzes the transformation of cyclic nucleotides into 5' nucleotides. Based on rodents, the current mammalian model of PDE distribution in the ovarian follicle predicts Pde3a in the oocyte and Pde4d in the somatic cells. Using bovine as an experimental model, the present results showed that PDE3 was the predominant PDE activity in oocytes. However, cumulus cell cAMP-PDE activity was predominantly resistant to inhibition by 3-isobutyl-methylxantine, indicating PDE8 activity (60% of total PDE activity) and a minor role for PDE4 (<5%). A total of 20% of total oocyte PDE activity was also attributed to PDE8. The PDE activity measurements in mural granulosa cells from 2 to 6 mm in diameter suggest the presence of PDE4 and PDE8. In granulosa cells from follicles >10 mm, total PDE and PDE8 activities along with PDE8A protein level were increased compared with smaller follicles. The RT-PCR experiments showed that cumulus cells expressed PDE8A, PDE8B, and PDE10A. Western blot experiments showed PDE8A, PDE8B, and PDE4D proteins in mural granulosa cells and cumulus-oocyte complexes. PDE8 inhibition using dipyridamole in a dose-dependent manner increased cAMP levels in the cumulus-oocyte complexes and delayed oocyte nuclear maturation. These results are the first to demonstrate the functional presence of PDE8 in the mammalian ovarian follicle. This challenges the recently described cell-specific expression of cAMP-PDEs in the ovarian follicle and the notion that PDE4 is the predominant granulosa/cumulus cell PDE. These findings have implications for our understanding of hormonal regulation of folliculogenesis and the potential application of PDE inhibitors as novel contraceptives.
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PMID:Characterization of novel phosphodiesterases in the bovine ovarian follicle. 1935 67

Polycystic ovary syndrome (PCOS) is characterized by excessive theca cell androgen secretion, dependent upon LH, which acts through the intermediacy of 3',5'-cyclic adenosine monophosphate (cAMP). cAMP signaling pathways are controlled through regulation of its synthesis by adenylyl cyclases, and cAMP degradation by phosphodiesterases (PDEs). PDE8A, a high-affinity cAMP-specific PDE is expressed in the ovary and testis. Leydig cells from mice with a targeted mutation in the Pde8a gene are sensitized to the action of LH in terms of testosterone production. These observations led us to evaluate the human PDE8A gene as a PCOS candidate gene, and the hypothesis that reduced PDE8A activity or expression would contribute to excessive ovarian androgen production. We identified a rare variant (R136Q; NM_002605.2 c.407G > A) and studied another known single nucleotide polymorphism (SNP) (rs62019510, N401S) in the PDE8A coding sequence causing non-synonymous amino acid substitutions, and a new SNP in the promoter region (NT_010274.16:g.490155G > A). Although PDE8A kinetics were consistent with reduced activity in theca cell lysates, study of the expressed variants did not confirm reduced activity in cell-free assays. Sub-cellular localization of the enzyme was also not different among the coding sequence variants. The PDE8A promoter SNP and a previously described promoter SNP did not affect promoter activity in in vitro assays. The more common coding sequence SNP (N401S), and the promoter SNPs were not associated with PCOS in our transmission/disequilibrium test-based analysis, nor where they associated with total testosterone or dehydroepiandrosterone sulfate levels. These findings exclude a significant role for PDE8A as a PCOS candidate gene, and as a Las major determinant of androgen levels in women.
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PMID:PDE8A genetic variation, polycystic ovary syndrome and androgen levels in women. 1948 4

In ventricular myocytes, activation of protein kinase A (PKA) by 3'-5' cyclic adenosine monophosphate (cAMP) increases the force of contraction by increasing L-type Ca(2+) channel currents (I(Ca)) and sarcoplasmic reticulum (SR) Ca(2+) release during excitation-contraction coupling. Cyclic-nucleotide phosphodiesterases (PDEs) comprise a large family of enzymes whose role in the cell is to regulate the spatial and temporal profile of cAMP signals by controlling the degradation of this second messenger. At present, however, the molecular identity and functional roles of the PDEs expressed in ventricular myocytes are incompletely understood. Here, we tested the hypothesis that PDE8A plays a critical role in the modulation of at least one compartment of cAMP and hence PKA activity during beta-adrenergic receptor (betaAR) activation in ventricular myocytes. Consistent with this hypothesis, we found that PDE8A transcript and protein are expressed in ventricular myocytes. Our data indicate that evoked [Ca(2+)](i) transients and I(Ca) increased to a much larger extent in PDE8A null (PDE8A(-/-)) than in wild-type (WT) myocytes during beta-adrenergic signaling activation. In addition, Ca(2+) spark activity was higher in PDE8A(-/-) than in WT myocytes. Our data indicate that PDE8A is a novel cardiac PDE that controls one or more pools of cAMP implicated in regulation of Ca(2+) movement through cardiomyocyte.
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PMID:Phosphodiesterase 8A (PDE8A) regulates excitation-contraction coupling in ventricular myocytes. 2035 94


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