Multimers of anionic amphiphiles mimic calmodulin stimulation of cyclic nucleotide phosphodiesterase.
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ABSTRACT:
SUBMITTER: Gietzen K
PROVIDER: S-EPMC1153913 | biostudies-other | 1982 Dec
REPOSITORIES: biostudies-other
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Project description:Cyclic nucleotide phosphodiesterases (PDEs) through the degradation of cGMP play critical roles in maintaining cardiomyocyte homeostasis. Ca(2+)/calmodulin (CaM)-activated cGMP-hydrolyzing PDE1 family may play a pivotal role in balancing intracellular Ca(2+)/CaM and cGMP signaling; however, its function in cardiomyocytes is unknown.Herein, we investigate the role of Ca(2+)/CaM-stimulated PDE1 in regulating pathological cardiomyocyte hypertrophy in neonatal and adult rat ventricular myocytes and in the heart in vivo.Inhibition of PDE1 activity using a PDE1-selective inhibitor, IC86340, or downregulation of PDE1A using siRNA prevented phenylephrine induced pathological myocyte hypertrophy and hypertrophic marker expression in neonatal and adult rat ventricular myocytes. Importantly, administration of the PDE1 inhibitor IC86340 attenuated cardiac hypertrophy induced by chronic isoproterenol infusion in vivo. Both PDE1A and PDE1C mRNA and protein were detected in human hearts; however, PDE1A expression was conserved in rodent hearts. Moreover, PDE1A expression was significantly upregulated in vivo in the heart and myocytes from various pathological hypertrophy animal models and in vitro in isolated neonatal and adult rat ventricular myocytes treated with neurohumoral stimuli such as angiotensin II (Ang II) and isoproterenol. Furthermore, PDE1A plays a critical role in phenylephrine-induced reduction of intracellular cGMP- and cGMP-dependent protein kinase (PKG) activity and thereby cardiomyocyte hypertrophy in vitro.These results elucidate a novel role for Ca(2+)/CaM-stimulated PDE1, particularly PDE1A, in regulating pathological cardiomyocyte hypertrophy via a cGMP/PKG-dependent mechanism, thereby demonstrating Ca(2+) and cGMP signaling cross-talk during cardiac hypertrophy.
| S-EPMC2803071 | biostudies-literature
Project description:Calmodulin-dependent phosphodiesterase (CaMPDE) is one of the key enzymes involved in the complex interactions which occur between the cyclic-nucleotide and Ca2+ second-messenger systems. Calmodulin-dependent phosphodiesterase exists in different isoenzymic forms, which exhibit distinct molecular and/or catalytic properties. The kinetic properties suggest that the 63 kDa brain isoenzyme is distinct from the brain 60 kDa and heart and lung CaMPDE isoenzymes. The CaMPDE isoenzymes of 60 kDa from brain, heart and lung are regulated by calmodulin, but the affinities for calmodulin are different. At identical concentrations of calmodulin, the bovine heart CaMPDE isoenzyme is stimulated at a much lower Ca2+ concentration than the bovine brain or lung isoenzymes. The bovine lung CaMPDE isoenzyme contains calmodulin as a tightly bound subunit, so that a change in calmodulin concentration had no effect on the [Ca2+]-dependence of activation of this isoenzyme. These observations are consistent with the notion that differential regulation by calmodulin and Ca2+ is an important function of these isoenzymes, which provide fine-tuning mechanisms for calmodulin action.
| S-EPMC1138026 | biostudies-other
Project description:The effects of KS-505a, a novel microbial metabolite, on the activity of calmodulin-dependent cyclic nucleotide phosphodiesterase (CaM-PDE) were investigated. (1) KS-505a potently inhibited the purified 61 kDa isoenzyme of CaM-PDE from bovine brain and required much higher doses to inhibit the purified 59 kDa isoenzyme of CaM-PDE from bovine heart. The inhibition of both isoenzymes was observed only in the presence of calcium-activated calmodulin (Ca2+/CaM). The IC50 values for the 61 and 59 kDa isoenzymes were 0.17 and 13 microM respectively with 20 microM cAMP as a substrate. (2) Kinetic analysis indicated that the inhibitory mode of KS-505a for the 61 kDa isoenzyme was competitive with respect to Ca2+/CaM; the K1 for KS-505a was 0.089 microM. The inhibition was not competitive with respect to the substrates cAMP or cGMP. (3) KS-505a did not interfere with the interaction between Ca2+/CaM and n-phenyll-naphthylamine, a hydrophobic fluorescent probe, nor was it adsorbed to CaM-conjugated gels in the presence of Ca2+, thereby indicating that KS-505a does not bind to Ca2+/CaM. (4) Trypsin-activated 61 kDa isoenzyme, which lacked the Ca2+/CaM-binding domain, was not inhibited by KS-505a at less than micromolar concentrations. Taken together, these results suggest that KS-505a apparently bound to a site in the Ca2+/CaM-binding domain of the 61 kDa isoenzyme and selectively inhibited Ca2+/CaM-activated 61 kDa isoenzyme activity. (5) In rat hippocampal slices, KS-505a at 10 micronM increased the intracellular cAMP concentration to approximately three times the basal level, whereas in rat striatal slices it had no effect on the cAMP concentration at concentrations of 1.0-10 microM, suggesting that each CaM-PDE isoenzyme functions differentially in these regions. These results demonstrate that KS-505a is a highly potent selective inhibitor both in vitro and in vivo and distinguishes between subfamily members within the CaM-PDE family.
| S-EPMC1217340 | biostudies-other
Project description:Cyclic nucleotide phosphodiesterase activity towards cyclic AMP and cyclic GMP was studied in extracts of rat islets of Langerhans. Biphasic Eadie plots [Eadie (1942) J. Biol. Chem. 146, 85-93] were obtained with either substrate suggesting the presence of both 'high'- and 'low'-Km components. The apparent Km values were 6.2 +/- 0.5 (n = 8) microM and 103.4 +/- 13.5 (6) microM for cyclic AMP and 3.6 +/- 0.3 (12) microM and 61.4 +/- 7.5 (13) microM for cyclic GMP. With cyclic AMP as substrate, phosphodeisterase activity was increased by calmodulin and Ca2+ and decreased by trifluoperazine, a specific inhibitor of calmodulin. With cyclic GMP as substrate, phosphodiesterase activity was decreased by omission of Ca2+ or addition of trifluoperazine. Addition of exogenous calmodulin had no effect on activity. The data suggest that Ca2+ may influence the islet content of cyclic AMP and cyclic GMP via effects on calmodulin-dependent cyclic nucleotide phosphodiesterase(s).
| S-EPMC1163146 | biostudies-other
Project description:The second messengers, cAMP and cGMP, regulate a number of physiological processes in the myocardium, from acute contraction/relaxation to chronic gene expression and cardiac structural remodeling. Emerging evidence suggests that multiple spatiotemporally distinct pools of cyclic nucleotides can discriminate specific cellular functions from a given cyclic nucleotide-mediated signal. Cyclic nucleotide phosphodiesterases (PDEs), by hydrolyzing intracellular cyclic AMP and/or cyclic GMP, control the amplitude, duration, and compartmentation of cyclic nucleotide signaling. To date, more than 60 different isoforms have been described and grouped into 11 broad families (PDE1-PDE11) based on differences in their structure, kinetic and regulatory properties, as well as sensitivity to chemical inhibitors. In the heart, PDE isozymes from at least six families have been investigated. Studies using selective PDE inhibitors and/or genetically manipulated animals have demonstrated that individual PDE isozymes play distinct roles in the heart by regulating unique cyclic nucleotide signaling microdomains. Alterations of PDE activity and/or expression have also been observed in various cardiac disease models, which may contribute to disease progression. Several family-selective PDE inhibitors have been used clinically or pre-clinically for the treatment of cardiac or vascular-related diseases. In this review, we will highlight both recent advances and discrepancies relevant to cardiovascular PDE expression, pathophysiological function, and regulation. In particular, we will emphasize how these properties influence current and future development of PDE inhibitors for the treatment of pathological cardiac remodeling and dysfunction.
| S-EPMC2966469 | biostudies-literature
Project description:Abdominal aortic aneurysm (AAA) is characterized by aorta dilation due to wall degeneration, which mostly occurs in elderly males. Vascular aging is implicated in degenerative vascular pathologies, including AAA. Cyclic nucleotide phosphodiesterases, by hydrolyzing cyclic nucleotides, play critical roles in regulating vascular structure remodeling and function. Cyclic nucleotide phosphodiesterase 1C (PDE1C) expression is induced in dedifferentiated and aging vascular smooth muscle cells (SMCs), while little is known about the role of PDE1C in aneurysm. We observed that PDE1C was not expressed in normal aorta but highly induced in SMC-like cells in human and murine AAA. In mouse AAA models induced by Angiotensin II or periaortic elastase, PDE1C deficiency significantly decreased AAA incidence, aortic dilation, and elastin degradation, which supported a causative role of PDE1C in AAA development in vivo. Pharmacological inhibition of PDE1C also significantly suppressed preestablished AAA. We showed that PDE1C depletion antagonized SMC senescence in vitro and/or in vivo, as assessed by multiple senescence biomarkers, including senescence-associated β-galactosidase activity, γ-H2AX foci number, and p21 protein level. Interestingly, the role of PDE1C in SMC senescence in vitro and in vivo was dependent on Sirtuin 1 (SIRT1). Mechanistic studies further showed that cAMP derived from PDE1C inhibition stimulated SIRT1 activation, likely through a direct interaction between cAMP and SIRT1, which leads to subsequent up-regulation of SIRT1 expression. Our findings provide evidence that PDE1C elevation links SMC senescence to AAA development in both experimental animal models and human AAA, suggesting therapeutical significance of PDE1C as a potential target against aortic aneurysms.
| S-EPMC8346800 | biostudies-literature
Project description:Recently we have reported that the ?C-helix in the cyclic nucleotide binding domain (CNBD) is required for channel regulation and function of cyclic nucleotide gated ion channels (CNGCs) in Arabidopsis. A mutation at arginine 557 to cysteine (R557C) in the ?C-helix of the CNBD caused an alteration in channel regulation. Protein sequence alignments revealed that R557 is located in a region that is important for calmodulin (CaM) binding. It has been hypothesized that CaM negatively regulates plant CNGCs similar to their counter parts in animals. However, only a handful of studies has been published so far and we still do not have much information about the regulation of CNGCs by CaM. Here, we conducted in silico binding prediction of CaM and Arabidopsis CNGC12 (AtCNGC12) to further study the role of R557. Our analysis revealed that R557 forms salt bridges with both D79 and E83 in AtCaM1. Interestingly, a mutation of R557 to C causes the loss of these salt bridges. Our data further suggests that this alteration in CaM binding causes the observed altered channel regulation and that R557 plays an important role in CaM binding.
| S-EPMC3115090 | biostudies-literature
Project description:Cyclic nucleotide phosphodiesterase (PDE) isoforms can influence disease pathogenesis and be novel therapeutic targets. Because lower cAMP levels may contribute to the decreased apoptosis that occurs in chronic lymphocytic leukemia (CLL), we assessed the expression levels of PDE isoforms in peripheral blood mononuclear cells (PBMC) of healthy adults and patients with CLL. We found a unique PDE mRNA signature in CLL: higher levels than in normal PBMC of PDE7B (increased approximately 23-fold) and lower levels of PDE3B, 4D, 5A, and 9A mRNA (each decreased approximately 30-fold). Increased PDE7B mRNA in CLL correlates with a 10-fold-higher expression of PDE7B protein and results in an increased contribution of PDE7 to total PDE activity. Consistent with the higher level of PDE7B expression, inhibitors of PDE7 (BRL-50481, IR-202) and a dual PDE4/PDE7 inhibitor (IR-284) selectively increase apoptosis in CLL cells compared with normal PBMC or B cells. Apoptosis of CLL cells promoted by inhibitors of PDE7 and PDE4/7 is attenuated by PKA inhibition, occurs via a mitochondrial-dependent process, and is associated with increased cAMP accumulation and down-regulation of the antiapoptotic protein survivin and of PDE7B. The increase in PDE7B expression and PDE7 inhibitor-promoted apoptosis implicates PDE7B as a drug target in CLL. Our findings identify a unique PDE signature in CLL and illustrate the utility of broad analyses of PDE isoform expression in human disease.
| S-EPMC2614795 | biostudies-literature
Project description:Cyclic nucleotide phosphodiesterase (PDE) exists as multiple molecular forms. Of the 11 families of PDE identified so far, PDE4, a cAMP-specific PDE, has been identified as the major isoform regulating inflammatory activity. The principle aim of the present study was to determine whether human basophils and human lung mast cells express PDE4. Four sub-classes of PDE4 (A, B, C, and D) have been identified and expression of these was determined by RT-CPR and by western blotting. In basophils, prominent expression of mRNA for PDE4A and PDE4D was observed whereas little if any expression of PDE4B and PDE4C was detected. These findings were paralleled by immunoblotting experiments as human basophils were found to express PDE4A and PDE4D with little evidence for the presence of either PDE4B or PDE4C. By contrast, human lung mast cells expressed very little, if any, mRNA for PDE4 sub-classes although, in some preparations, some modest levels of mRNA for PDE4D were detected. However, there was no evidence, at the protein level, that mast cells express PE4. Overall, these data indicate that basophils express PDE4 (4A and 4D) whereas human lung mast cells do not.
| S-EPMC5806836 | biostudies-literature
Project description:Cyclic nucleotide phosphodiesterases (PDEs) regulate intracellular levels of cAMP and cGMP by hydrolyzing them to their corresponding 5' monophosphates. We report here the cloning and characterization of a novel cAMP-specific PDE from mouse testis. This unique phosphodiesterase contains a catalytic domain that overall shares <40% sequence identity to the catalytic domain of all other known PDEs. Based on this limited homology, this new PDE clearly represents a previously unknown PDE gene family designated as PDE8. The cDNA for PDE8 is 3,678 nucleotides in length and is predicted to encode an 823 amino acid enzyme. The cDNA includes a full ORF as it contains an in-frame stop codon before the start methionine. PDE8 is specific for the hydrolysis of cAMP and has a Km of 0.15 microM. Most common PDE inhibitors are ineffective antagonists of PDE8, including the nonspecific PDE inhibitor 3-isobutyl-1-methylxanthine. Dipyridamole, however, an inhibitor that is generally considered to be relatively specific for the cGMP selective PDEs, does inhibit PDE8 with an IC50 of 4.5 microM. Tissue distribution studies of 22 different mouse tissues indicates that PDE8 has highest expression in testis, followed by eye, liver, skeletal muscle, heart, 7-day embryo, kidney, ovary, and brain in decreasing order. In situ hybridizations in testis, the tissue of highest expression, shows that PDE8 is expressed in the seminiferous epithelium in a stage-specific manner. Highest levels of expression are seen in stages 7-12, with little or no expression in stages 1-6.
| S-EPMC21190 | biostudies-literature