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

In the present study, the effects of cAMP- and cGMP-phosphodiesterase (PDE) inhibitors, theophylline, and sildenafil on secretion of protein, amylase and epidermal growth factor (EGF) and the flow rate from rat submandibular saliva were examined in an acute experiment. Theophylline at doses of 25, 50, 85mgkg(-1) and sildenafil at doses of 1, 2, 5mgkg(-1) were administered intraperitoneally 2h before saliva collection. Pure submandibular saliva was collected intraorally by microployethylene tubes under anesthesia using dissecting microscope. Theophylline at doses of 25, 50, 85mgkg(-1) increased salivary flow rate to 197% (P<0.01), 186% (P<0.01), and 209% of control, respectively. Sildenafil at doses of 1, 2, 5mgkg(-1) also increased flow rate to 232% (P<0.01), 182% (P<0.01), and 197% of control, respectively. Theophylline at doses of 25, 50, 85mgkg(-1) increased total protein concentration to 98% (P<0.01), 84% (P<0.01), and 210% of control, respectively. Sildenafil at doses of 2 and 5mgkg(-1) increased total protein concentration to 75% (P<0.01), and 240% of control, respectively. Theophylline at dose of 85mgkg(-1) increased EGF concentration to 60% (P<0.01) of control. Sildenafil at doses of 2 and 5mgkg(-1) increased EGF concentration to 44% (P<0.05) and 90% (P<0.01) of control, respectively. No statistically significant change was observed in amylase activity by administration of theophylline or sildenafil. The present results indicate that increasing intracellular levels of cAMP and cGMP have stimulatory effects on salivary functions. Regarding beneficiary effects of increased salivary flow rate and secretion of EGF in maintaining oral health, theophylline and sildenafil may find good places in some oral diseases.
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PMID:Stimulation by theophylline and sildenafil of rat submandibular secretion of protein, epidermal growth factor and flow rate. 1296 88

We examined the cAMP-mediated regulation of the epidermal growth factor-like growth factor amphiregulin (AR) in T cells and observed a strong cAMP-induced up-regulation of AR mRNA in a time- and concentration-dependent manner independent of T cell activation. This regulation may be mediated in part through activation of a cAMP-responsive element in the AR promoter, because the cAMP-responsive element conferred cAMP responsiveness to a luciferase reporter in Jurkat TAg cells. Similar effects of AR mRNA induction were seen in T cells treated with cAMP-elevating agents such as prostaglandin E(2) and forskolin as well as with the phosphodiesterase inhibitors rolipram and isobutylmethylxanthine. Furthermore, the induction of AR mRNA by cAMP was strongly suppressed by a protein kinase A type I-selective inhibitor, whereas treatment with an exchange protein directly activated by cAMP-specific agonist did not increase AR levels. In addition, an increase in AR gene transcripts by cAMP was seen in MCF-7 mammary carcinoma cells and H295R adrenal cells. Moreover, the potent cAMP-mediated induction of AR mRNA resulted in increased secretion (5-fold) of AR from T cells. Furthermore, supernatants from cAMP-stimulated T cells containing secreted AR induced phosphorylated MAPK in OVCAR-3 carcinoma cells. In conclusion, our data suggest that AR is under strong regulation by the cAMP pathway in various cell types, and that prostaglandin E(2)- and cAMP-induced AR secretion from T cells may be highly relevant in a microenvironment consisting of tumor cells and infiltrated immune cells, because AR by activating the MAPK pathway through a paracrine route may contribute to proliferation of tumor cells and thus add to neoplastic processes.
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PMID:The epidermal growth factor-like growth factor amphiregulin is strongly induced by the adenosine 3',5'-monophosphate pathway in various cell types. 1528 8

Germinal vesicle (GV)-stage oocytes retrieved from antral follicles undergo nuclear maturation in vitro, which typically occurs prior to cytoplasmic maturation. Short-term culture with meiotic inhibitors has been applied to arrest oocytes at the GV stage aiming to synchronize nuclear and ooplasmic maturity. However, the results obtained are still far from the in vivo situation. In order to acquire competence, immature oocytes may require meiotic arrest in vitro for a more extended period. The phosphodiesterase type 3-inhibitor (PDE3-I) is a potent meiotic arrester. The effects of a prolonged culture with PDE3-I on oocyte quality prior to and after reversal from the inhibition are not known. This study tested the impact of long-term in vitro exposure of two PDE3-Is, org9935 and cilostamide, on oocytes using a mouse follicle culture model. The results showed that PDE3-I (maximum of 10 microM) during a 12-day culture of follicle-enclosed oocytes did not alter somatic cell proliferation, differentiation or follicle survival. In addition, the steroid production profile was not significantly modified by a 12-day exposure to PDE3-I. The recombinant human chorionic gonadotrophin/recombinant human epidermal growth factor stimulus induced a characteristic normal progesterone peak of luteinization and normal mucification of the cumulus cells, while the enclosed oocyte remained blocked at the GV stage. In vitro maturation of denuded or cumulus-enclosed oocytes derived from org9935- or cilostamide-exposed follicles progressed through meiosis and formed morphologically normal meiotic spindles with chromosomes properly aligned at the equator. In conclusion, long-term culture with PDE3-I was harmless to somatic cell function, differentiation, oocyte growth and maturation. Our results suggested that PDE3-I can be applied when extended oocyte culture is required to improve ooplasmic maturation.
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PMID:Effects of long-term in vitro exposure to phosphodiesterase type-3 inhibitors on follicle and oocyte development. 1604 55

In recent years, pulmonary hypertension got into the focus of research due to the development of efficacious medications and the discovery of important pathologic mechanisms of disease. Currently, prostanoids, endothelin receptor antagonists and phosphodiesterase 5 inhibitors are the most important substance groups used for treatment. Substances that are emerging in tumor therapy (tyrosine kinase inhibitors, epidermal growth factor [EGF] und platelet-derived growth factor [PDGF] receptor blockers), vasoactive intestinal peptide (VIP), rho-kinase inhibitors and targeted drugs for endothelial dysfunction will be evaluated as future drugs for pulmonary hypertension. Improving early diagnosis of pulmonary hypertension will be an important task in the future. Both the development of diagnostic methods with increased sensitivity and specificity and a broad awareness program will be necessary to achieve this goal.
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PMID:[Pulmonary hypertension: the future has begun]. 1660 90

Chronic obstructive pulmonary disease [COPD] is characterised by airflow limitation of peripheral airways that is not fully reversible and progressive and is associated with an abnormal inflammatory response of the lungs to noxious particles or gases. There is also intense airway wall remodelling and evidence of systemic inflammation. Increased interleukin [IL]-6, IL-1beta, tumor necrosis factor-alpha [TNF-alpha], GRO-alpha, MCP-1 and IL-8 levels are measured in sputum, with further increases during exacerbations. The bronchiolar epithelium over-expresses MCP-1, MIP-1alpha and IL-8. IL-8 can account for sputum neutrophil chemotactic activity. TNFalpha and IL-1beta stimulate macrophages to produce matrix metalloproteinase-9 [MMP-9], and bronchial epithelial cells to produce extracellular matrix glycoproteins. Increased expression of transforming growth factor-beta [TGFbeta) and epidermal growth factor [EGF] occurs in the epithelium and submucosal cells; gene array studies reveal an excess of TGFbeta1, CTGF and PDGFRA in COPD. TGFbeta and EGF activate proliferation of fibroblasts, while activation of the EGF receptor leads to mucin gene expression. Anti-cytokine therapy could be in the form of soluble receptors or by neutralising antibodies, small compounds blocking cytokine receptors or incomplete and non-activating cytokines, inhibitors of protein activation and inhibitors of signal transduction and transcription such as via inhibition of mitogen-activated protein kinases [MAPK] and of transcription factor, nuclear factor kappaB. Anti-IL-8 therapy has been tried with little effect on COPD, and current trials are on-going with TNF-alpha inhibitors. Other treatments such as phosphodiesterase 4 inhibitors have anti-cytokine effects that may underlie their beneficial effects in COPD.
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PMID:Cytokines as targets in chronic obstructive pulmonary disease. 1678 67

It is well established that cAMP signaling is an important regulator of the oocyte meiotic cell cycle. Conversely, the function of cGMP during oocyte maturation is less clear. Herein, we evaluated the expression of cGMP-hydrolyzing phosphodiesterases (PDEs) in the somatic and germ cell compartments of the mouse ovarian follicle and demonstrate that PDE5 is preferentially expressed in somatic cells. Cyclic GMP is a potent inhibitor of cAMP hydrolysis from oocyte extracts, with a 50% inhibitory concentration of 97 nM. Luteinizing hormone (LH) stimulation of cultured preovulatory follicles results in a marked decrease in cGMP content, and a nadir is reached in 1.5 h; similarly, oocyte cGMP levels decrease after gonadotropin stimulation in vivo. The LH-dependent decrease in cGMP requires activation of the epidermal growth factor network. Treatment of follicles with a PDE5 inhibitor increases cGMP in the follicle well above unstimulated levels. Although LH causes a decrease in cGMP in follicles preincubated with PDE5 inhibitors, the levels of this nucleotide remain above unstimulated levels. Under these conditions of elevated cGMP, LH stimulation does not cause oocyte maturation after 5 h of incubation. Microinjection of a cGMP-specific PDE into oocytes causes meiotic maturation of wild-type oocytes, suggesting that an intraoocyte pool of cGMP is involved in the maintenance of meiotic arrest. This effect is absent in PDE3A-deficient oocytes. Taken together, these findings provide evidence that cGMP and cAMP signaling cooperate in maintaining meiotic arrest via regulation of PDE3A and that a decrease in cGMP in the somatic compartment is one of the signals contributing to meiotic maturation.
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PMID:Cyclic GMP signaling is involved in the luteinizing hormone-dependent meiotic maturation of mouse oocytes. 1947 61

Mammalian oocytes reach prophase of first meiosis around the time of birth, and remain at this stage for months or years, depending on the species. Only after puberty will the fully-grown oocytes begin to resume meiosis which is stimulated by gonadotropin surge. It has long been known that a high level of intra-oocyte cyclic adenosine 3',5'-monophosphate (cAMP) prevents oocyte meiosis resumption as indicated by germinal vesicle breakdown (GVBD). Recently, guanosine triphosphate-binding (G) protein-coupled receptors/G proteins/adenyl cyclase pathway endogenous to the oocyte as well as cAMP diffusion from the somatic compartment through gap junctions have been implicated in maintaining cAMP at levels that prevent oocytes from resuming meiosis. Another second messager molecule, guanosine 3',5'-cyclic monophosphate (cGMP), has also recently been found to play important roles in maintaining oocyte meiosis arrest. cGMP in the follicular somatic cells diffuses into the oocyte and causes an increase in oocyte cAMP, presumably by acting on phosphodiesterase 3 (PDE3). The cGMP level in the somatic compartment of the follicle decreases in response to luteinizing hormone (LH), and this change may be mediated through the epidermal growth factor (EGF)-like factors and specific cGMP-phosphodiesterase subtype activity. It is well known that gonadotropic stimulation of meiotic resumption depends on mitogen-activated protein kinase (MAPK) activation in the somatic compartment of the follicle; recent studies show that LH, through cAMP/protein kinase A (PKA) and protein kinase C (PKC) pathways, induces the synthesis of paracine factors such as EGF-like facors and meiosis activating sterol (MAS) to regulate oocyte GVBD via the MAPK pathway in follicle cells. A recent granulosa cell-specific knockout study has for the first time provided in vivo evidence for the important role of extracellular regulated kinase 1 and 2 (ERK1/2), two main forms of MAPK, and their downstream molecules in granulosa cells in oocyte meiosis resumption. Unresolved questions and future directions on research regarding signaling changes in follicle cells and oocytes as well their communication in response to the gonadotropin surge are addressed in this review.
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PMID:Towards a new understanding on the regulation of mammalian oocyte meiosis resumption. 1971 79

PC12 cells exhibit precise temporal control of growth factor signaling in which stimulation with epidermal growth factor (EGF) leads to transient extracellular signal-regulated kinase (ERK) activity and cell proliferation, whereas nerve growth factor (NGF) stimulation leads to sustained ERK activity and differentiation. While cyclic AMP (cAMP)-mediated signaling has been shown to be important in conferring the sustained ERK activity achieved by NGF, little is known about the regulation of cAMP and cAMP-dependent protein kinase (PKA) in these cells. Using fluorescence resonance energy transfer (FRET)-based biosensors localized to discrete subcellular locations, we showed that both NGF and EGF potently activate PKA at the plasma membrane, although they generate temporally distinct activity patterns. We further show that both stimuli fail to induce cytosolic PKA activity and identify phosphodiesterase 3 (PDE3) as a critical regulator in maintaining this spatial compartmentalization. Importantly, inhibition of PDE3, and thus perturbation of the spatiotemporal regulation of PKA activity, dramatically increases the duration of EGF-stimulated nuclear ERK activity in a PKA-dependent manner. Together, these findings identify EGF and NGF as potent activators of PKA activity specifically at the plasma membrane and reveal a novel regulatory mechanism contributing to the growth factor signaling specificity achieved by NGF and EGF in PC12 cells.
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PMID:Spatiotemporally regulated protein kinase A activity is a critical regulator of growth factor-stimulated extracellular signal-regulated kinase signaling in PC12 cells. 2180

Penile erection is a neurovascular phenomenon, and erectile dysfunction (ED) is caused mainly by vascular risk factors or diseases, neurologic abnormalities, and hormonal disturbances. Men with diabetic ED often have severe endothelial dysfunction and peripheral nerve damage, which result in poor response to oral phosphodiesterase-5 inhibitors. Nerve injury-induced protein 1 (Ninjurin 1, Ninj1) is known to be involved in neuroinflammatory processes and to be related to vascular regression during the embryonic period. Here, we demonstrate in streptozotocin-induced diabetic mice that inhibition of the Ninj1 pathway by administering Ninj1-neutralizing antibody (Ninj1-Ab) or by using Ninj1-knockout mice successfully restored erectile function through enhanced penile angiogenesis and neural regeneration. Angiopoietin-1 (Ang1) expression was down-regulated and angiopoietin-2 expression was up-regulated in the diabetic penis compared with that in controls, and these changes were reversed by treatment with Ninj1-Ab. Ninj1 blockade-mediated penile angiogenesis and neural regeneration as well as recovery of erectile function were abolished by inhibition of Ang1-Tie2 (tyrosine kinase with Ig and epidermal growth factor homology domain-2) signaling with soluble Tie2 antibody or Ang1 siRNA. The present results suggest that inhibition of the Ninj1 pathway will be a novel therapeutic strategy for treating ED.
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PMID:Inhibition of Ninjurin 1 restores erectile function through dual angiogenic and neurotrophic effects in the diabetic mouse. 2497 88

Premature luteinization is a possible cause of infertility in women. It is currently unknown whether environmental chemicals can induce changes associated with premature luteinization. Using rat granulosa cells (GC) in vitro, we demonstrated that exposure to atrazine (ATR), a widely used herbicide, causes GC phenotype that resembles that of human premature luteinization. At the end of the 48-h stimulation with FSH, ATR-exposed GC showed (1) higher levels of progesterone, (2) overexpression of luteal markers (Star and Cyp11a1), and (3) an increase in progesterone:estradiol ratio above 1. Mechanistic experiments were conducted to understand the signaling events engaged by ATR that lead to this phenotype. Western blot analysis revealed prolonged phosphorylation of protein kinase B (AKT) and cAMP response element-binding protein (CREB) in ATR- and FSH-exposed GC. An increased level of ERK1/2-dependent transcriptional factor CCATT/enhancer-binding protein beta (CEBPB) was observed after 4 h of ATR exposure. Inhibitors of PI3K (wortmannin) and MEK (U0126) prevented ATR-induced rise in progesterone level and expression of luteal markers in FSH-stimulated GC. Atrazine intensified AKT and CEBPB signaling and caused Star overexpression in forskolin-stimulated GC but not in epidermal growth factor (EGF)-stimulated GC. In the presence of rolipram, a specific inhibitor of phosphodiesterase 4 (PDE4), ATR was not able to further elevate AKT phosphorylation, CEBPB protein level, and Star mRNA in FSH-stimulated GC, suggesting that ATR inhibits PDE4. Overall, this study showed that ATR acts as a FSH sensitizer leading to enhanced cAMP, AKT, and CEBPB signaling and progesterone biosynthesis, which promotes premature luteinization phenotype in GC.
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PMID:Atrazine enhances progesterone production through activation of multiple signaling pathways in FSH-stimulated rat granulosa cells: evidence for premature luteinization. 2525 36


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