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Cyclic GMP (cGMP) translates and integrates much of the information encoded by nitric oxide (NO · ) and several natriuretic peptides, including the atrial natriuretic peptide (ANP). Previously, we reported that integration of a cGMP-specific cyclic nucleotide phosphodiesterase, namely phosphodiesterase 5A (PDE5A), into a protein kinase G (PKG)- and inositol-1,4,5-trisphosphate receptor (IP 3 R)-containing endoplasmic reticulum (ER) signalosome allows localized control of PDE5A activity and of PKG-dependent inhibition of IP 3 -mediated release of ER Ca 2 + in human platelets. Herein, we report that PDE5A integrates into an analogous signalosome in human arterial smooth muscle cells (HASMC), wherein it regulates muscarinic agonist-dependent Ca 2 + release and is activated selectively by PKG-dependent phosphorylation. In addition, we report that PDE5A also regulates HASMC functions via events independent of PKG, but rather through actions coordinated by competitive cGMP-mediated inhibition of cAMP hydrolysis by the so-called cGMP-inhibited cAMP PDE, namely phosphodiesterase 3A (PDE3A). Indeed, we show that ANP increases both cGMP and cAMP levels in HASMC and promotes phosphorylation of vasodilator-stimulated phospho-protein (VASP) at each the PKG and PKA phospho-acceptor sites. Since selective inhibition of PDE5 decreased DNA synthesis and chemotaxis of HASMC, and that PDE3A knockdown obviated these effects, our findings are consistent with a role for a PDE5A-PDE3A-PKA axis in their regulation. Our findings provide insight into the existence of distinct “pools” of PDE5A in HASMC and support the idea that these discrete compartments regulate distinct cGMP-dependent events. As a corollary, we suggest that it may be possible to target these distinct PDE5A-regulated pools and in so-doing differentially impact selected cGMP-regulated functions in these cells. [ABSTRACT FROM AUTHOR]

Specific functions for different cyclic nucleotide phosphodiesterases (PDEs) have not yet been identified in most cell types. Conventional approaches to study PDE function typically rely on measurements of global cAMP, general increases in cAMP-dependent protein kinase (PKA), or the activity of exchange protein activated by cAMP (EPAC). Although newer approaches using subcellularly targeted FRET reporter sensors have helped define more compartmentalized regulation of cAMP, PKA, and EPAC, they have limited ability to link this regulation to downstream effector molecules and biological functions. To address this problem, we have begun to use an unbiased mass spectrometry-based approach coupled with treatment using PDE isozyme-selective inhibitors to characterize the phosphoproteomes of the functional pools of cAMP/PKA/EPAC that are regulated by specific cAMP-PDEs (the PDE-regulated phosphoproteomes). In Jurkat cells we find multiple, distinct PDE-regulated phosphoproteomes that can be defined by their responses to different PDE inhibitors. We also find that little phosphorylation occurs unless at least two different PDEs are concurrently inhibited in these cells. Moreover, bioinformatics analyses of these phosphoproteomes provide insight into the unique functional roles, mechanisms of action, and synergistic relationships among the different PDEs that coordinate cAMP-signaling cascades in these cells. The data strongly suggest that the phosphorylation of many different substrates contributes to cAMP-dependent regulation of these cells. The findings further suggest that the approach of using selective, inhibitor-dependent phosphoproteome analysis can provide a generalized methodology for understanding the roles of different PDEs in the regulation of cyclic nucleotide signaling. [ABSTRACT FROM AUTHOR]

Aim of the Study: Idiopathic pulmonary fibrosis (IPF) is a lethal human disease with short survival time and few treatment options. In this study, we aim to demonstrate that cyclic nucleotide phosphodiesterase 1A (PDE1A), a Ca2+/calmodulin-stimulating PDE family member, plays a critical role in the induction of fibrosis and angiogenesis in the lung. Materials and Methods: To induce pulmonary damage, adult male SD rats were treated with bleomycin in a dose of 6 mg/kg body weight by a single intratracheal instillation. For in vivo silencing of PDE1A in rat lung, a nonspecific control siRNA or PDE1A-specific siRNA was used to treat rat through nasal instillation. Human normal pulmonary fibroblasts MRC-5 and hFL1 and rat lung fibroblasts were used as in vitro model. Immunohistochemistry and immunoflurescence staining were performed to detect PDE1A and α-SMA expression. Reverse transcription-qPCR was performed to detect microRNA and mRNA expression. In vitro wound healing assay was performed to detect pulmonary fibroblasts'mortality ability. Results: In vitro studies showed that PDE1A can stimulate lung fibroblasts to undergo myofibroblastic changes. This led to the identification of miR-541-5p as one of the miRNA candidates associated with bleomycin response. We found that miR-541-5p expression is downregulated in TGF-β-treated lung fibroblasts and the rat pulmonary fibrosis model. Overexpression of miR-541-5p in lung fibroblasts inhibited mortality of human lung fibroblasts. Conclusions: MiR-541-5p is a key effector in lung fibroblastsby by regulating PDE1A expression at protein translation level and its overexpression is protective against bleomycin-induced lung fibrosis. [ABSTRACT FROM AUTHOR]

Mitochondria play a critical role in skeletal muscle metabolism and function, notably at the level of tissue respiration, which conduct muscle strength as well as muscle survival. Pathological conditions induce mitochondria dysfunctions notably characterized by free oxygen radical production disturbing intracellular signaling. In that way, the second messengers, cyclic AMP and cyclic GMP, control intracellular signaling at the physiological and transcription levels by governing phosphorylation cascades. Both nucleotides are specifically and selectively hydrolyzed in their respective 5′-nucleotide by cyclic nucleotide phosphodiesterases (PDEs), which constitute a multi-genic family differently tissue distributed and subcellularly compartmentalized. These PDEs are presently recognized as therapeutic targets for cardiovascular, pulmonary, and neurologic diseases. However, very few data concerning cyclic nucleotides and PDEs in skeletal muscle, specifically in mitochondria, are reported in the literature. The knowledge of PDE implication in mitochondrial signaling would be helpful for resolving critical mitochondrial dysfunctions in skeletal muscle. [ABSTRACT FROM AUTHOR]

Photoactivated adenylyl cyclase (PAC) and guanylyl cyclase rhodopsin increase the concentrations of intracellular cyclic nucleotides upon illumination, serving as promising secondgeneration tools in optogenetics. To broaden the arsenal of such tools, it is desirable to have light-activatable enzymes that can decrease cyclic nucleotide concentrations in cells. Here, we report on an unusual microbial rhodopsin that may be able to meet the demand. It is found in the choanoflagellate Salpingoeca rosetta and contains a C-terminal cyclic nucleotide phosphodiesterase (PDE) domain. We examined the enzymatic activity of the protein (named Rh-PDE) both in HEK293 membranes and whole cells. Although Rh-PDE was constitutively active in the dark, illumination increased its hydrolytic activity 1.4-fold toward cGMP and 1.6-fold toward cAMP, as measured in isolated crude membranes. Purified full-length Rh-PDE displayed maximal light absorption at 492 nm and formed the M intermediate with the deprotonated Schiff base upon illumination. The M state decayed to the parent spectral state in 7 s, producing long-lasting activation of the enzyme domain with increased activity. We discuss a possible mechanism of the Rh-PDE activation by light. Furthermore, Rh-PDE decreased cAMP concentration in HEK293 cells in a light-dependent manner and could do so repeatedly without losing activity. Thus, Rh-PDE may hold promise as a potential optogenetic tool for light control of intracellular cyclic nucleotides (e.g. to study cyclic nucleotide-associated signal transduction cascades). [ABSTRACT FROM AUTHOR]

Lipids rafts are specialised membrane microdomains involved in cell signalling that can be isolated as detergent-resistant membranes (DRMs). The second messenger cyclic AMP (cAMP) has a central role in cell signalling in the ovary and its degradation is carried out by the phosphodiesterase (PDE) enzyme family. We hypothesised that PDEs could be functionally present in the lipid rafts of porcine mural granulosa cell membranes. PDE6C, PDE8A and PDE11A were detected by dot blot in the DRMs and the Triton-soluble fraction of the mural granulosa cells membrane and the cytosol. As shown by immunocytochemistry, PDEs showed clear immunostaining in mural granulosa cell membranes and the cytosol. Interestingly, cAMP-PDE activity was 18 times higher in the DRMs than in the Triton-soluble fraction of cell membranes and was 7.7 times higher in the cytosol than in the DRMs. cAMP-PDE activity in mural granulosa cells was mainly contributed by the PDE8 and PDE11 families. This study shows that PDEs from the PDE8 and PDE11 families are present in mural granulosa cells and that the cAMP-PDE activity is mainly contributed by the cytosol. In the cell membrane, the cAMP-PDE activity is mainly contributed by the DRMs. In addition, receptors for prostaglandin E2 and LH, two G-protein-coupled receptors, are present in lipid rafts and absent from the non-raft fraction of the granulosa cell membrane. These results suggest that in these cells, the lipid rafts exist as a cell-signalling platform and PDEs are one of the key enzyme families present in the raft. [ABSTRACT FROM AUTHOR]

Cyclic nucleotide phosphodiesterase 10A (PDE10A) regulates the level of the second messengers cAMP and cGMP in particular in brain regions assumed to be associated with neurodegenerative and psychiatric diseases. A better understanding of the pathophysiological role of the expression of PDE10A could be obtained by quantitative imaging of the enzyme by positron emission tomography (PET). Thus, in this study we developed, radiolabeled, and evaluated a new PDE10A radioligand, 8-bromo-1-(6-[18F]fluoropyridin-3-yl)-3,4-dimethylimidazo[1,5- a]quinoxaline ([18F] AQ28A). [18F] AQ28A was radiolabeled by both nucleophilic bromo-to-fluoro or nitro-to-fluoro exchange using K[18F]F-K2.2.2-carbonate complex with different yields. Using the superior nitro precursor, we developed an automated synthesis on a Tracerlab FX F-N module and obtained [18F] AQ28A with high radiochemical yields (33 ± 6%) and specific activities (96-145 GBq·μmol−1) for further evaluation. Initially, we investigated the binding of [18F] AQ28A to the brain of different species by autoradiography and observed the highest density of binding sites in striatum, the brain region with the highest PDE10A expression. Subsequent dynamic PET studies in mice revealed a region-specific accumulation of [18F] AQ28A in this region, which could be blocked by preinjection of the selective PDE10A ligand MP-10. In conclusion, the data suggest [18F] AQ28A is a suitable candidate for imaging of PDE10A in rodent brain by PET. [ABSTRACT FROM AUTHOR]

The process of aging is considered to be tightly related to mitochondrial dysfunction. One of the causes of aging is an increased sensitivity to the induction of mitochondrial permeability transition pore (mPTP) opening in the inner membrane of mitochondria. Melatonin, a natural antioxidant, is a hormone produced by the pineal gland. The role of melatonin whose level decreases with aging is well understood. In the present study, we demonstrated that long-term treatment of aged rats with melatonin improved the functional state of mitochondria; thus, the Ca 2 + capacity was enhanced and mitochondrial swelling was deaccelerated in mitochondria. Melatonin prevented mPTP and impaired the release of cytochrome c and 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) from mitochondria of both young and aged rats. Our data suggest that melatonin retains СNPase inside mitochondria, thereby providing the protection of the protein against deleterious effects of 2′,3′-cAMP in aging. [ABSTRACT FROM AUTHOR]

Highlights from the article: Combined levodopa/decarboxylase inhibitor treatment was initiated and proved to be effective in both sisters leading to a reduction of chorea, hyperkinesia and motor restlessness (Video - segment 2). In the older sister therapy was started with 0,67/0,17 mg/kg/day levodopa/benserazide divided into two doses and augmented to 1/0,25 mg/kg/day levodopa/benserazide divided into three doses within three weeks. For patients with benign hereditary chorea levodopa therapy has been shown to effectively reduce hyperkinetic movements [[11]] but to our knowledge has not been tested in patients with a hyperkinetic movement disorder due to mutations in phosphodiesterases. Combined levodopa/decarboxylase inhibitor therapy also showed effectiveness in both here reported children leading to a reduction of hyperkinetic symptoms.

Cyclic nucleotide phosphodiesterase 1C (PDE1C) represents a major phosphodiesterase activity in human myocardium, but its function in the heart remains unknown. Using genetic and pharmacological approaches, we studied the expression, regulation, function, and underlying mechanisms of PDE1C in the pathogenesis of cardiac remodeling and dysfunction. PDE1C expression is up-regulated in mouse and human failing hearts and is highly expressed in cardiac myocytes but not in fibroblasts. In adult mouse cardiac myocytes, PDE1C deficiency or inhibition attenuated myocyte death and apoptosis, which was largely dependent on cyclic AMP/PKA and PI3K/AKT signaling. PDE1C deficiency also attenuated cardiac myocyte hypertrophy in a PKA-dependent manner. Conditioned medium taken from PDE1C-deficient cardiac myocytes attenuated TGF-β-stimulated cardiac fibroblast activation through a mechanism involving the crosstalk between cardiac myocytes and fibroblasts. In vivo, cardiac remodeling and dysfunction induced by transverse aortic constriction, including myocardial hypertrophy, apoptosis, cardiac fibrosis, and loss of contractile function, were significantly attenuated in PDE1C-knockout mice relative to wild-type mice. These results indicate that PDE1C activation plays a causative role in pathological cardiac remodeling and dysfunction. Given the continued development of highly specific PDE1 inhibitors and the high expression level of PDE1C in the human heart, our findings could have considerable therapeutic significance. [ABSTRACT FROM AUTHOR]

Cyclic nucleotide phosphodiesterases (PDEs) are the only enzymes that degrade the cyclic nucleotides cAMP and cGMP, and play a key role in modulating the amplitude and duration of the signal delivered by these two key intracellular second messengers. Defects in cyclic nucleotide signalling are known to be involved in several pathologies. As a consequence, PDEs have long been recognized as potential drug targets, and they have been the focus of intense research for the development of therapeutic agents. A number of PDE inhibitors are currently available for the treatment of disease, including obstructive pulmonary disease, erectile dysfunction, and heart failure. However, the performance of these drugs is not always satisfactory, due to a lack of PDE-isoform specificity and their consequent adverse side effects. Recent advances in our understanding of compartmentalised cyclic nucleotide signalling and the role of PDEs in local regulation of cAMP and cGMP signals offers the opportunity for the development of novel strategies for therapeutic intervention that may overcome the current limitation of conventional PDE inhibitors. [ABSTRACT FROM AUTHOR]

In mammals, adenosine 3’, 5’-cyclic monophosphate (cAMP) is known to play highly important roles in sperm motility and acrosomal exocytosis. It is known to act through protein phosphorylation via PRKA and through the activation of guanine nucleotide exchange factors like EPAC. Sperm intracellular cAMP levels depend on the activity of adenylyl cyclases, mostly SACY, though transmembrane-containing adenylyl cyclases are also present, and on the activity of cyclic nucleotide phosphodiesterases (PDE) whose role is to degrade cAMP into 5’-AMP. The PDE superfamily is subdivided into 11 families (PDE1 to 11), which act on either cAMP or cGMP, or on both cAMP and cGMP although with different enzymatic properties. PDE10, which is more effective on cAMP than cGMP, has been known for almost 15 years and is mostly studied in the brain where it is associated with neurological disorders. Although a high level of PDE10A gene expression is observed in the testis, information on the identity of the isoforms or on the cell type that express the PDE10 protein is lacking. The objective of this study was to identify the PDE10A isoforms expressed in the testis and germ cells, and to determine the presence and localization of PDE10A in mature spermatozoa. As a sub-objective, since PDE10A transcript variants were reported strictly through analyses of bovine genomic sequence, we also wanted to determine the nucleotide and amino acid sequences by experimental evidence. Using RT-PCR, 5’- and 3’-RACE approaches we clearly show that PDE10A transcript variants X3 and X5 are expressed in bovine testis as well as in primary spermatocytes and spermatids. We also reveal using a combination of immunological techniques and proteomics analytical tools that the PDE10A isoform X4 is present in the area of the developing acrosome of spermatids and of the acrosome of mature spermatozoa. [ABSTRACT FROM AUTHOR]

Purpose: A positron emission tomography (PET) tracer for the enzyme phosphodiesterase 10A (PDE10A) is desirable to guide the discovery and development of PDE10A inhibitors as potential therapeutics. The preclinical characterization of the PDE10A PET tracer [(11)C]MK-8193 is described.Procedures: In vitro binding studies with [(3)H]MK-8193 were conducted in rat, monkey, and human brain tissue. PET studies with [(11)C]MK-8193 were conducted in rats and rhesus monkeys at baseline and following administration of a PDE10A inhibitor.Results: [(3)H]MK-8193 is a high-affinity, selective PDE10A radioligand in rat, monkey, and human brain tissue. In vivo, [(11)C]MK-8193 displays rapid kinetics, low test-retest variability, and a large specific signal that is displaced by a structurally diverse PDE10A inhibitor, enabling the determination of pharmacokinetic/enzyme occupancy relationships.Conclusions: [(11)C]MK-8193 is a useful PET tracer for the preclinical characterization of PDE10A therapeutic candidates in rat and monkey. Further evaluation of [(11)C]MK-8193 in humans is warranted. [ABSTRACT FROM AUTHOR]

Phosphodiesterase-4 (PDE4) inhibitors prevent the breakdown of the second messenger cAMP and have been demonstrated to improve learning in several animal models of cognition. In this study, we explored the antioxidative effects of rolipram in Alzheimer's disease (AD) by using bilateral Aβ25-35 injection into the hippocampus of rats, which were used as an AD model. Rats received 3 intraperitoneal (i.p.) doses of rolipram (0.1, 0.5 and 1.25 mg/kg) daily after the injection of Aβ25-35 for 25 days. Chronic administration of rolipram prevented the memory impairments induced by Aβ25-35, as assessed using the passive avoidance test and the Morris water maze test. Furthermore, rolipram significantly reduced the oxidative stress induced by Aβ25-35, as evidenced by the decrease in the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and restored the reduced GSH levels and superoxide dismutase (SOD) activity. Moreover, western blotting and real-time reverse transcription polymerase chain reaction (RT-PCR) analysis showed that rolipram remarkably upregulated thioredoxin (Trx) and inhibited the inducible nitric oxide synthase/nitric oxide (iNOS/NO) pathway in the hippocampus. These results demonstrated that rolipram improved the learning and memory abilities in an Aβ25-35-induced AD rat model. The mechanism underlying these effects may be due to the noticeable antioxidative effects of rolipram. [ABSTRACT FROM AUTHOR]

Cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) are now recognized as important intracellular signalling molecules that modulate cardiac sympatho-vagal balance in the progression of heart disease. Recent studies have identified that a significant component of autonomic dysfunction associated with several cardiovascular pathologies resides at the end organ, and is coupled to impairment of cyclic nucleotide targeted pathways linked to abnormal intracellular calcium handling and cardiac neurotransmission. Emerging evidence also suggests that cyclic nucleotide coupled phosphodiesterases (PDEs) play a key role limiting the hydrolysis of cAMP and cGMP in disease, and as a consequence this influences the action of the nucleotide on its downstream biological target. In this review, we illustrate the action of nitric oxide-CAPON signalling and brain natriuretic peptide on cGMP and cAMP regulation of cardiac sympatho-vagal transmission in hypertension and ischaemic heart disease. Moreover, we address how PDE2A is now emerging as a major target that affects the efficacy of soluble/particulate guanylate cyclase coupling to cGMP in cardiac dysautonomia. [ABSTRACT FROM AUTHOR]

PDE4 family cAMP-selective cyclic nucleotide phosphodiesterases are important in the regulation of cAMP abundance in numerous systems, and thereby play an important role in the regulation of PKA and EPAC activity and the phosphorylation of CREB. We have used the yeast 2-hybrid system to demonstrate recently that long PDE4 isoforms form homodimers, consistent with data obtained recently by structural studies. The long PDE4 isoform PDE4D5 interacts selectively with β-arrestin2, implicated in the regulation of G-protein-coupled receptors and other cell signaling components, and also with the β-propeller protein RACK1. In the present study, we use 2-hybrid approaches to demonstrate that RACK1 and β-arrestin2 inhibit the dimerization of PDE4D5. We also show that serine-to-alanine mutations at PKA and ERK1/2 phosphorylation sites on PDE4D5 detectably ablate dimerization. Conversely, phospho-mimic serine-to-aspartate mutations at the MK2 and oxidative stress kinase sites ablate dimerization. Analysis of PDE4D5 that is locked into the dimeric configuration by the formation of a trans disulfide bond between Ser261 and Ser602 shows that RACK1 interacts strongly with both the monomeric and dimeric forms, but that β-arrestin2 interacts exclusively with the monomeric form. This is consistent with the concept that β-arrestin2 can preferentially recruit the monomeric, or “open,” form of PDE4D5 to β 2 -adrenergic receptors, where it can regulate cAMP signaling. [ABSTRACT FROM AUTHOR]

Nearly 10 years ago the laboratory of Miles Houslay was part of a collaboration which identified and characterized the interaction between Disrupted in Schizophrenia 1 and phosphodiesterase type 4. This work has had significant impact on our thinking of psychiatric illness causation and the potential for therapeutics. [ABSTRACT FROM AUTHOR]

Many cellular processes are modulated by cyclic AMP and nucleotide phosphodiesterases (PDEs) regulate this second messenger by catalyzing its breakdown. The major unique function of testicular Leydig cells is to produce testosterone in response to luteinizing hormone (LH). Treatment of Leydig cells with PDE inhibitors increases cAMP levels and the activity of its downstream effector, cAMP-dependent protein kinase (PKA), leading to a series of kinase-dependent signaling and transcription events that ultimately increase testosterone release. We have recently shown that PDE4B and PDE4C as well as PDE8A and PDE8B are expressed in rodent Leydig cells and that combined inhibition of PDE4 and PDE8 leads to dramatically increased steroid biosynthesis. Here we investigated the effect of PDE4 and PDE8 inhibition on the molecular mechanisms of cAMP actions in a mouse MA10 Leydig cell line model with SILAC mass spectrometry-based phosphoproteomics. We treated MA10 cells either with PDE4 family specific inhibitor (Rolipram) and PDE8 family specific inhibitor (PF-04957325) alone or in combination and quantified the resulting phosphorylation changes at five different time points between 0 and 180 min. We identified 28,336 phosphosites from 4837 proteins and observed significant regulation of 749 sites in response to PDE4 and PDE8 inhibitor treatment. Of these, 132 phosphosites were consensus PKA sites. Our data strongly suggest that PDE4 and PDE8 inhibitors synergistically regulate phosphorylation of proteins required for many different cellular processes, including cell cycle progression, lipid and glucose metabolism, transcription, endocytosis and vesicle transport. Our data suggests that cAMP, PDE4 and PDE8 coordinate steroidogenesis by acting on not one rate-limiting step but rather multiple pathways. Moreover, the pools of cAMP controlled by these PDEs also coordinate many other metabolic processes that may be regulated to assure timely and sufficient testosterone secretion in response to LH. [ABSTRACT FROM AUTHOR]

The role of primary blast in blast-induced traumatic brain injury (bTBI) is controversial in part due to the technical difficulties of generating free-field blast conditions in the laboratory. The use of traditional shock tubes often results in artifacts, particularly of dynamic pressure, whereas the forces affecting the head are dependent on where the animal is placed relative to the tube, whether the exposure is whole-body or head-only, and on how the head is actually exposed to the insult (restrained or not). An advanced blast simulator (ABS) has been developed that enables high-fidelity simulation of free-field blastwaves, including sharply defined static and dynamic overpressure rise times, underpressures, and secondary shockwaves. Rats were exposed in head-only fashion to single-pulse blastwaves of 15 to 30 psi static overpressure. Head restraints were configured so as to eliminate concussive and minimize whiplash forces exerted on the head, as shown by kinematic analysis. No overt signs of trauma were present in the animals post-exposure. However, significant changes in brain 2′,3′-cyclic nucleotide 3′-phosphohydrolase (CNPase) and neurofilament heavy chain levels were evident by 7 days. In contrast to most studies of primary blast-induced TBI (PbTBI), no elevation of glial fibrillary acidic protein (GFAP) levels was noted when head movement was minimized. The ABS described in this article enables the generation of shockwaves highly representative of free-field blast. The use of this technology, in concert with head-only exposure, minimized head movement, and the kinematic analysis of the forces exerted on the head provide convincing evidence that primary blast directly causes changes in brain function and that GFAP may not be an appropriate biomarker of PbTBI. [ABSTRACT FROM AUTHOR]

Copyright of Biologie Aujourd'hui is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) is an abundant membrane-associated enzyme within the vertebrate myelin sheath. While the physiological function of CNPase still remains to be characterized in detail, it is known – in addition to its in vitro enzymatic activity – to interact with other proteins, small molecules, and membrane surfaces. From an evolutionary point of view, it can be deduced that CNPase is not restricted to myelin-forming cells or vertebrate tissues. Its evolution has involved gene fusion, addition of other small segments with distinct functions, such as membrane attachment, and possibly loss of function at the polynucleotide kinase-like domain. Currently, it is unclear whether the enzymatic function of the conserved phosphodiesterase domain in vertebrate myelin has a physiological role, or if CNPase could actually function – like many other classical myelin proteins – in a more structural role. This article is part of a Special Issue entitled SI: Myelin Evolution . [ABSTRACT FROM AUTHOR]

Copyright of Archives of Cardiovascular Diseases is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Escherichia coli RtcB is a founding member of a family of manganese-dependent RNA repair enzymes that join RNA 2',3'-cyclic phosphate (RNA>p) or RNA 3'-phosphate (RNAp) ends to 5'-OH RNA (HORNA) ends in a multistep pathway whereby RtcB (i) hydrolyzes RNA>p to RNAp, (ii) transfers GMP from GTP to RNAp to form to RNAppG, and (iii) directs the attack of 5'-OH on RNAppG to form a 3'-5' phosphodiester splice junction. The crystal structure of the homologous archaeal RtcB enzyme revealed an active site with two closely spaced manganese ions, Mn1 and Mn2, that interact with the GTP phosphates. By studying the reactions of wild-type E. coli RtcB and RtcB alanine mutants with 3'-phosphate-, 2',3'-cyclic phosphate-, and 3'-ppG-terminated substrates, we found that enzymic constituents of the two metal coordination complexes (Cys78, His185, and His281 for Mn1 and Asp75, Cys78, and His168 for Mn2 in E. coli RtcB) play distinct catalytic roles. For example, whereas the C78A mutation abolished all steps assayed, the D75A mutation allowed cyclic phosphodiester hydrolysis but crippled 3'-phosphate guanylylation, and the H281A mutant was impaired in overall HORNAp and HORNA>p ligation but was able to seal a preguanylylated substrate. The archaeal counterpart of E. coli RtcB Arg189 coordinates a sulfate anion construed to mimic the position of an RNA phosphate. We propose that Arg189 coordinates a phosphodiester at the 5'-OH end, based on our findings that the R189A mutation slowed the step of RNAppG/HORNA sealing by a factor of 200 compared to that with wild-type RtcB while decreasing the rate of RNAppG formation by only 3-fold. [ABSTRACT FROM AUTHOR]

Rationale and objectives: Cyclic nucleotide phosphodiesterase-2 (PDE2) is a potential therapeutic target for the treatment of cognitive dysfunction. Using the object recognition test (ORT), this study assessed the effects of two PDE2 inhibitors, Bay 60-7550 and ND7001, on learning and memory, and examined underlying mechanisms. Methods: To assess the role of PDE2 inhibition on phases of memory, Bay 60-7550 (3 mg/kg) was administered: 30 min prior to training; 0, 1, or 3 h after training; or 30 min prior to recall testing. To assess cyclic nucleotide involvement in PDE2 inhibitor-enhanced memory consolidation, either the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 20 mg/kg; intraperitoneal (IP)), soluble guanylyl cyclase inhibitor 1H-[−1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ; 20 mg/kg; IP), protein kinase G inhibitor KT5823 (2.5 μg; intracerebroventricular (ICV)), or protein kinase A inhibitor H89 (1 μg; ICV) was administered 30 min prior to the PDE2 inhibitor Bay 60-7550 (3 mg/kg) or ND7001 (3 mg/kg). Changes in the phosphorylation of 3'5'-cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) at Ser-133 and vasodilator-stimulated phosphoprotein (VASP) at Ser-239 were determined to confirm activation of cAMP and 3'5'-cyclic guanosine monophosphate (cGMP) signaling. Results: Bay 60-7550 (3 mg/kg) enhanced memory of mice in the ORT when given 30 min prior to training, immediately after training, or 30 min prior to recall. Inhibitors of the cGMP pathway blocked the memory-enhancing effects of both Bay 60-7550 (3 mg/kg) and ND7001 (3 mg/kg) on early consolidation processes. Bay 60-7550 (3 mg/kg) enhanced phosphorylation of CREB and VASP, both targets of cGMP-dependent protein kinase (PKG). Conclusions: These results confirm a potential of PDE2, or components of its signaling pathway, as a therapeutic target for drug discovery focused on restoring memory function. [ABSTRACT FROM AUTHOR]

Trypanosoma cruzi is the etiological agent of Chagas disease or American trypanosomiasis, a neglected tropical condition historically endemic to Latin America that, due to human migration, has spread beyond its traditional boundaries. It is now estimated that 6 to 8 million people suffer from this disease worldwide. T. cruzi is a protozoan parasite that presents a complex life cycle, during which it must cope with sudden changes in the environment to which it must respond immediately to survive. Cyclic nucleotide phosphodiesterases have been implicated in the proliferation, differentiation and osmotic regulation of trypanosomatids. In some trypanosomatid species they have been validated as molecular targets for the development of new therapeutic agents. It has also been shown that many inhibitors of mammalian PDEs lack an inhibitory effect on trypanosomatid enzymes, indicating that there are differences in the substrate specificity of parasite and host enzymes, foreshadowing the possibility of identifying compounds that selectively inhibit the parasite enzyme. The limited possibilities to edit T. cruzi genome have made it difficult to carry out knockout and knockdown experiments, and drug target validation has been limited to biochemical evaluations. Recently, the development of CRISPR/Cas9 as a tool for genomic edition brought a new perspective to the study of Trypanosoma cruzi. According to the most often applied protocols, epimastigotes are co-transfected with a single plasmid bearing both the gene for Cas9-GFP expression and a sequence to be translated into a single guide RNA (sgRNA), jointly with a lineal donor DNA encompassing a selection marker flanked by sequences homologous to the target gene. Here, we tested an alternative approach for the generation of Phosphodiesterase (PDE) knockout parasites. We obtained epimastigotes from Tul II strain stably expressing Cas9-GFP in the nucleus in all parasite stages, with no detrimental effects on epimastigote growth or differentiation nor on trypomastigote infection capability. These Cas9-GFP epimastigotes were co-transfected with the sgRNA + DNA donor pair, according to the intended gene target. sgRNA were obtained by in vitro transcription using a template DNA bearing the specific + scaffold sequence under a T7 promoter. To obtain the donor DNA we designed a pre-donor formed by a sequence including several restriction enzyme recognition sites flanked by 30-bp arms homologous to the sequence adjacent sgRNA annealing target. This pre-donor allowed to easily generate a variety of donor DNAs by cloning alternative selection markers. DNA extracts (boiling-preps) from 4-day post-transfection cultures were evaluated by PCR using mixed primer pairs: while one of the primers annealed to the target gene, the second primer annealed to a sequence in the donor DNA, allowing assessment of its correct insertion in the gene of interest. Advantages of this take on CRISPR/Cas9 edition include its versatility for choosing and switching between alternative selection markers and a quick and affordable generation of the components of the system and analysis of the transfected cultures, while possibly facilitating complementation assays on the KO lines. Finally, our results indicate that loss of PDEs (even partial) is incompatible with normal parasite function/parasite viability. [ABSTRACT FROM AUTHOR]

Gastric cancer is the fourth most common cancer type and the second leading cause of cancer-associated mortality worldwide. Metastasis is a crucial feature of its progression. DNA methylation provides a key epigenetic signature in the epigenetic regulation pathway, and is implicated in transcriptional regulation. CpG sites, which are associated with gene transcriptional activity, are underrepresented in the mammalian genome and tend to be clustered within CpG islands (CGIs) located in the vicinity of the transcription start sites of the majority of the protein-coding genes in humans. The DNA methylation inhibitor, decitabine (DAC), has been demonstrated to be active in hematological disorders. The majority of previous studies in cancer cells demonstrated that DAC inhibits cell proliferation and the motility of the cells. However, since demethylation across the entire genome alters the expression of a large number of genes, the effects of DAC in different tumor cell types are difficult to accurately predict. Neural precursor cell-expressed, developmentally downregulated (NEDD)4-1, a member of the NEDD4 family, which belongs to the E3-ubiquitin ligase family, was reported to be highly expressed in a wide range of tumor types, and it activates the phosphoinositide 3-kinase/Akt pathway by degrading phosphatase and tensin homolog. NEDD4-1 promotes the migration and invasion of glioma cells via the ubiquitination and subsequent degradation of cyclic nucleotide-Ras guanine nucleotide exchange factors (CNrasGEFs). In gastric cardia adenocarcinoma, NEDD4-1 acts as an exceptional prognostic biomarker. In the present study, DAC was revealed to promote the invasive properties of MGC803 gastric cancer cells. NEDD4-1 targeted the CNrasGEF-mediated DAC invasion-promoting activity in MGC803 cells, and CGI methylation in neither the NEDD4 promoter nor the first intron was demonstrated to be associated with this effect. The results of the present study revealed that DAC exerts variable effects in different gastric cancer cell lines and may provide a reference for DAC administration in the clinic. [ABSTRACT FROM AUTHOR]

A causal relationship between ginsenoside Rb3 (G-Rb3) and improved inflammation and cardiac function has not been established. To determine which specific signaling pathways were involved in G-Rb3 improvement of inflammation and myocardial function. In vivo , we found that G-Rb3 decreased the levels of both nuclear factor κB (NF-κB p65) and CD45, an inflammatory marker. G-Rb3 also enhanced key proteins of the contraction unit (cardiac troponin protein I (cTnI) and α-actinin) to improve cardiac function. G-Rb3 inhibited NF-κB p65 nuclear translocation in vitro, as verified by western blot and IF. When NF-κB p65 was overexpressed, a decrease in cyclic nucleotide phosphodiesterase 3B (PDE3B) and SERCA2a expression, while no statistical significance was observed in the expressions of cAMP, PKA, and calcium/calmodulin-dependent protein kinase type II (CaMKⅡ) in each group. The NF-κB p65 plasmid blocked the SERCA2a promoter, as verified by the luciferase reporter system, and G-Rb3 truncated the NF-κB p65 block on the SERCA2a promoter. qPCR was also used to confirm that G-Rb3 increased the mRNA of SERCA2a. In conclusion, we confirmed that the mechanisms of G-Rb3 on ventricular systolic dysfunction causing inflammation are not via the cAMP/PKA pathway, but via suppressing the blockage of NF-κB p65 on the SERCA2a promoter and increasing the SERCA2a expression. [Display omitted] • NF-κB p65 regulated SERCA2a by directly binding at the SERCA2a promoter rather than the cAMP/PKA pathway. • The molecular mechanism of ginsenoside Rb3 in the relation between the inflammation and contractile activity is implicated in that G-Rb3 truncated the NF-κB p65 blocker on the SERCA2a promoter. [ABSTRACT FROM AUTHOR]

We previously reported that 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP) is present in rat brain and liver mitochondria, in the outer membrane and mitoplasts. Substrates of CNP, 2′,3′-cAMP and 2′,3′-cNADP, were found to accelerate opening of mitochondrial permeability transition pore (mPTP). In purified non-synaptic mitochondria, CNP was observed to co-immunoprecipitate with main modulators of mPTP, i.e. VDAC, ANT, and cyclophilin D, as well as with tubulin and COX IV. Using Blue Native Electrophoresis, with following Western blot, CNP was revealed to associate with functional inner membrane mitochondrial complexes I–V. In Ca 2+ -overloaded mitochondria, association of CNP with complexes I–V was decreased. Cyclosporine A increased the association of CNP with complexes I and III, supporting the idea of the involvement of these complexes in mPTP function. 2′,3′-cAMP enhanced CNP dissociation from complexes I, III, IV and V in Ca 2+ -overloaded mitochondria (i.e. when pore is opened). Association of CNP with complexes I, III, IV, and V was shown in mitochondria isolated from brain, liver and heart. Stimulation of the opening of the non-selective pore in mitochondria correlated with CNP release from mitochondria in parallel with release of cytochrome c, AIF and Endo G. In Ca 2+ -overloaded mitochondria, 2′,3′-cAMP further accelerated the release of AIF, Endo G and CNP, but did not alter cytochrome c release. These results provide strong evidence that CNP, one of the possible regulators of mPTP complex, might be involved in the control of respiration and energy production in mitochondria. This reveals a new function of CNP outside the myelin structure. [ABSTRACT FROM AUTHOR]

Autosomal-dominant hypertension with brachydactyly is a salt-independent Mendelian syndrome caused by activating mutations in the gene encoding phosphodiesterase 3A. These mutations increase the protein kinase A- mediated phosphorylation of phosphodiesterase 3A resulting in enhanced cAMP-hydrolytic affinity and accelerated cell proliferation. The phosphorylated vasodilator-stimulated phosphoprotein is diminished, and parathyroid hormonerelated peptide is dysregulated, potentially accounting for all phenotypic features. Untreated patients die prematurely of stroke; however, hypertension-induced target-organ damage is otherwise hardly apparent. We conducted clinical studies of vascular function, cardiac functional imaging, platelet function in affected and nonaffected persons, and cell-based assays. Large-vessel and cardiac functions indeed seem to be preserved. The platelet studies showed normal platelet function. Cell-based studies demonstrated that available phosphodiesterase 3A inhibitors suppress the mutant isoforms. However, increasing cGMP to indirectly inhibit the enzyme seemed to have particular use. Our results shed more light on phosphodiesterase 3A activation and could be relevant to the treatment of severe hypertension in the general population. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim A Kampo medicine, kososan ( KS), has been used clinically for the treatment of certain depression-like symptoms. Our previous studies using the stress-induced depression-like model mice, showed that oral KS treatment leads to an antidepressive-like effect via the normalization of dysfunction of hypothalamic-pituitary-adrenal axis. In the present study, proteomic analysis was used to identify brain hypothalamus proteins that are affected by KS treatment. Methods KS was orally administered to stress-induced depression-like model mice at 1.0 g/kg/day for 9 days, and the hypothalamus was then analyzed using agarose 2-D gel electrophoresis, followed by mass spectrometry-based protein identification, and then western blot analysis and immunohistochemical analysis. Results The expression of eight proteins was increased or decreased in the hypothalamus of the model mice, but recovered on oral KS treatment. Among them, metabotropic glutamate receptor 2 ( mGluR2) and 2′,3′-cyclic nucleotide 3′-phosphodiesterase 1 ( CNPase1) were identified as depression-related proteins. Western blot of the hypothalamus confirmed these results and showed that the expression of CNPase2 was opposite to that of CNPase1. On immunohistochemistry, mGluR2 expression in the hypothalamus paraventricular nucleus was downregulated and CNPase2 expression was upregulated in the cerebral fornix in the model mouse, but KS returned them to normal. Conclusion mGluR2 and CNPase in the hypothalamus are associated with the antidepressive-like activity of KS. [ABSTRACT FROM AUTHOR]