1
|
Vinogradova TM, Lakatta EG. Dual Activation of Phosphodiesterase 3 and 4 Regulates Basal Cardiac Pacemaker Function and Beyond. Int J Mol Sci 2021. [PMID: 34445119 DOI: 10.3390/ijms22168414.pmid:34445119;pmcid:pmc8395138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
Abstract
The sinoatrial (SA) node is the physiological pacemaker of the heart, and resting heart rate in humans is a well-known risk factor for cardiovascular disease and mortality. Consequently, the mechanisms of initiating and regulating the normal spontaneous SA node beating rate are of vital importance. Spontaneous firing of the SA node is generated within sinoatrial nodal cells (SANC), which is regulated by the coupled-clock pacemaker system. Normal spontaneous beating of SANC is driven by a high level of cAMP-mediated PKA-dependent protein phosphorylation, which rely on the balance between high basal cAMP production by adenylyl cyclases and high basal cAMP degradation by cyclic nucleotide phosphodiesterases (PDEs). This diverse class of enzymes includes 11 families and PDE3 and PDE4 families dominate in both the SA node and cardiac myocardium, degrading cAMP and, consequently, regulating basal cardiac pacemaker function and excitation-contraction coupling. In this review, we will demonstrate similarities between expression, distribution, and colocalization of various PDE subtypes in SANC and cardiac myocytes of different species, including humans, focusing on PDE3 and PDE4. Here, we will describe specific targets of the coupled-clock pacemaker system modulated by dual PDE3 + PDE4 activation and provide evidence that concurrent activation of PDE3 + PDE4, operating in a synergistic manner, regulates the basal cardiac pacemaker function and provides control over normal spontaneous beating of SANCs through (PDE3 + PDE4)-dependent modulation of local subsarcolemmal Ca2+ releases (LCRs).
Collapse
Affiliation(s)
- Tatiana M Vinogradova
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institute of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institute of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| |
Collapse
|
2
|
Dual Activation of Phosphodiesterase 3 and 4 Regulates Basal Cardiac Pacemaker Function and Beyond. Int J Mol Sci 2021; 22:ijms22168414. [PMID: 34445119 PMCID: PMC8395138 DOI: 10.3390/ijms22168414] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/01/2021] [Accepted: 08/02/2021] [Indexed: 11/17/2022] Open
Abstract
The sinoatrial (SA) node is the physiological pacemaker of the heart, and resting heart rate in humans is a well-known risk factor for cardiovascular disease and mortality. Consequently, the mechanisms of initiating and regulating the normal spontaneous SA node beating rate are of vital importance. Spontaneous firing of the SA node is generated within sinoatrial nodal cells (SANC), which is regulated by the coupled-clock pacemaker system. Normal spontaneous beating of SANC is driven by a high level of cAMP-mediated PKA-dependent protein phosphorylation, which rely on the balance between high basal cAMP production by adenylyl cyclases and high basal cAMP degradation by cyclic nucleotide phosphodiesterases (PDEs). This diverse class of enzymes includes 11 families and PDE3 and PDE4 families dominate in both the SA node and cardiac myocardium, degrading cAMP and, consequently, regulating basal cardiac pacemaker function and excitation-contraction coupling. In this review, we will demonstrate similarities between expression, distribution, and colocalization of various PDE subtypes in SANC and cardiac myocytes of different species, including humans, focusing on PDE3 and PDE4. Here, we will describe specific targets of the coupled-clock pacemaker system modulated by dual PDE3 + PDE4 activation and provide evidence that concurrent activation of PDE3 + PDE4, operating in a synergistic manner, regulates the basal cardiac pacemaker function and provides control over normal spontaneous beating of SANCs through (PDE3 + PDE4)-dependent modulation of local subsarcolemmal Ca2+ releases (LCRs).
Collapse
|
3
|
New aspects in cardiac L-type Ca2+ channel regulation. Biochem Soc Trans 2020; 48:39-49. [PMID: 32065210 DOI: 10.1042/bst20190229] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/24/2020] [Accepted: 01/24/2020] [Indexed: 12/23/2022]
Abstract
Cardiac excitation-contraction coupling is initiated with the influx of Ca2+ ions across the plasma membrane through voltage-gated L-type calcium channels. This process is tightly regulated by modulation of the channel open probability and channel localization. Protein kinase A (PKA) is found in close association with the channel and is one of the main regulators of its function. Whether this kinase is modulating the channel open probability by phosphorylation of key residues or via alternative mechanisms is unclear. This review summarizes recent findings regarding the PKA-mediated channel modulation and will highlight recently discovered regulatory mechanisms that are independent of PKA activity and involve protein-protein interactions and channel localization.
Collapse
|
4
|
Vinogradova TM, Sirenko S, Lukyanenko YO, Yang D, Tarasov KV, Lyashkov AE, Varghese NJ, Li Y, Chakir K, Ziman B, Lakatta EG. Basal Spontaneous Firing of Rabbit Sinoatrial Node Cells Is Regulated by Dual Activation of PDEs (Phosphodiesterases) 3 and 4. Circ Arrhythm Electrophysiol 2019; 11:e005896. [PMID: 29880528 DOI: 10.1161/circep.117.005896] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/27/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Spontaneous firing of sinoatrial node cells (SANCs) is regulated by cAMP-mediated, PKA (protein kinase A)-dependent (cAMP/PKA) local subsarcolemmal Ca2+ releases (LCRs) from RyRs (ryanodine receptors). LCRs occur during diastolic depolarization and activate an inward Na+/Ca2+ exchange current that accelerates diastolic depolarization rate prompting the next action potential. PDEs (phosphodiesterases) regulate cAMP-mediated signaling; PDE3/PDE4 represent major PDE activities in SANC, but how they modulate LCRs and basal spontaneous SANC firing remains unknown. METHODS Real-time polymerase chain reaction, Western blot, immunostaining, cellular perforated patch clamping, and confocal microscopy were used to elucidate mechanisms of PDE-dependent regulation of cardiac pacemaking. RESULTS PDE3A, PDE4B, and PDE4D were the major PDE subtypes expressed in rabbit SANC, and PDE3A was colocalized with α-actinin, PDE4D, SERCA (sarcoplasmic reticulum Ca2+ ATP-ase), and PLB (phospholamban) in Z-lines. Inhibition of PDE3 (cilostamide) or PDE4 (rolipram) alone increased spontaneous SANC firing by ≈20% (P<0.05) and ≈5% (P>0.05), respectively, but concurrent PDE3+PDE4 inhibition increased spontaneous firing by ≈45% (P<0.01), indicating synergistic effect. Inhibition of PDE3 or PDE4 alone increased L-type Ca2+ current (ICa,L) by ≈60% (P<0.01) or ≈5% (P>0.05), respectively, and PLB phosphorylation by ≈20% (P>0.05) each, but dual PDE3+PDE4 inhibition increased ICa,L by ≈100% (P<0.01) and PLB phosphorylation by ≈110% (P<0.05). Dual PDE3+PDE4 inhibition increased the LCR number and size (P<0.01) and reduced the SR (sarcoplasmic reticulum) Ca2+ refilling time (P<0.01) and the LCR period (time from action potential-induced Ca2+ transient to subsequent LCR; P<0.01), leading to decrease in spontaneous SANC cycle length (P<0.01). When RyRs were disabled by ryanodine and LCRs ceased, dual PDE3+PDE4 inhibition failed to increase spontaneous SANC firing. CONCLUSIONS Basal cardiac pacemaker function is regulated by concurrent PDE3+PDE4 activation which operates in a synergistic manner via decrease in cAMP/PKA phosphorylation, suppression of LCR parameters, and prolongation of the LCR period and spontaneous SANC cycle length.
Collapse
Affiliation(s)
- Tatiana M Vinogradova
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD.
| | - Syevda Sirenko
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Yevgeniya O Lukyanenko
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Dongmei Yang
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Kirill V Tarasov
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Alexey E Lyashkov
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Nevin J Varghese
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Yue Li
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Khalid Chakir
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Bruce Ziman
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD
| |
Collapse
|
5
|
Vinogradova TM, Kobrinsky E, Lakatta EG. Dual Activation of Phosphodiesterases 3 and 4 Regulates Basal Spontaneous Beating Rate of Cardiac Pacemaker Cells: Role of Compartmentalization? Front Physiol 2018; 9:1301. [PMID: 30356755 PMCID: PMC6189467 DOI: 10.3389/fphys.2018.01301] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/29/2018] [Indexed: 12/17/2022] Open
Abstract
Spontaneous firing of sinoatrial (SA) node cells (SANCs) is regulated by cyclic adenosine monophosphate (cAMP)-mediated, protein kinase A (PKA)-dependent (cAMP/PKA) local subsarcolemmal Ca2+ releases (LCRs) from ryanodine receptors (RyR). The LCRs occur during diastolic depolarization (DD) and activate an inward Na+/Ca2+ exchange current that accelerates the DD rate prompting the next action potential (AP). Basal phosphodiesterases (PDEs) activation degrades cAMP, reduces basal cAMP/PKA-dependent phosphorylation, and suppresses normal spontaneous firing of SANCs. The cAMP-degrading PDE1, PDE3, and PDE4 represent major PDE activities in rabbit SANC, and PDE inhibition by 3-isobutyl-1-methylxanthine (IBMX) increases spontaneous firing of SANC by ∼50%. Though inhibition of single PDE1–PDE4 only moderately increases spontaneous SANC firing, dual PDE3 + PDE4 inhibition produces a synergistic effect hastening the spontaneous SANC beating rate by ∼50%. Here, we describe the expression and distribution of different PDE subtypes within rabbit SANCs, several specific targets (L-type Ca2+ channels and phospholamban) regulated by basal concurrent PDE3 + PDE4 activation, and critical importance of RyR Ca2+ releases for PDE-dependent regulation of spontaneous SANC firing. Colocalization of PDE3 and PDE4 beneath sarcolemma or in striated patterns inside SANCs strongly suggests that PDE-dependent regulation of cAMP/PKA signaling might be executed at the local level; this idea, however, requires further verification.
Collapse
Affiliation(s)
- Tatiana M Vinogradova
- Laboratory of Cardiovascular Science, Intramural Research Program, NIA, NIH, Baltimore, MD, United States
| | - Evgeny Kobrinsky
- Laboratory of Cardiovascular Science, Intramural Research Program, NIA, NIH, Baltimore, MD, United States
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Intramural Research Program, NIA, NIH, Baltimore, MD, United States
| |
Collapse
|
6
|
Bhogal NK, Hasan A, Gorelik J. The Development of Compartmentation of cAMP Signaling in Cardiomyocytes: The Role of T-Tubules and Caveolae Microdomains. J Cardiovasc Dev Dis 2018; 5:jcdd5020025. [PMID: 29751502 PMCID: PMC6023514 DOI: 10.3390/jcdd5020025] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/18/2018] [Accepted: 04/28/2018] [Indexed: 12/26/2022] Open
Abstract
3′-5′-cyclic adenosine monophosphate (cAMP) is a signaling messenger produced in response to the stimulation of cellular receptors, and has a myriad of functional applications depending on the cell type. In the heart, cAMP is responsible for regulating the contraction rate and force; however, cAMP is also involved in multiple other functions. Compartmentation of cAMP production may explain the specificity of signaling following a stimulus. In particular, transverse tubules (T-tubules) and caveolae have been found to be critical structural components for the spatial confinement of cAMP in cardiomyocytes, as exemplified by beta-adrenergic receptor (β-ARs) signaling. Pathological alterations in cardiomyocyte microdomain architecture led to a disruption in compartmentation of the cAMP signal. In this review, we discuss the difference between atrial and ventricular cardiomyocytes in respect to microdomain organization, and the pathological changes of atrial and ventricular cAMP signaling in response to myocyte dedifferentiation. In addition, we review the role of localized phosphodiesterase (PDE) activity in constraining the cAMP signal. Finally, we discuss microdomain biogenesis and maturation of cAMP signaling with the help of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Understanding these mechanisms may help to overcome the detrimental effects of pathological structural remodeling.
Collapse
Affiliation(s)
- Navneet K Bhogal
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
| | - Alveera Hasan
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
| | - Julia Gorelik
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
| |
Collapse
|
7
|
Parks RJ, Bogachev O, Mackasey M, Ray G, Rose RA, Howlett SE. The impact of ovariectomy on cardiac excitation-contraction coupling is mediated through cAMP/PKA-dependent mechanisms. J Mol Cell Cardiol 2017; 111:51-60. [PMID: 28778766 DOI: 10.1016/j.yjmcc.2017.07.118] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/11/2017] [Accepted: 07/28/2017] [Indexed: 12/18/2022]
Abstract
Ovariectomy (OVX) promotes sarcoplasmic reticulum (SR) Ca2+ overload in ventricular myocytes. We hypothesized that the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway contributes to this Ca2+ dysregulation. Myocytes were isolated from adult female C57BL/6 mice following either OVX or sham surgery (surgery at ≈1mos). Contractions, Ca2+ concentrations (fura-2) and ionic currents were measured simultaneously (37°C, 2Hz) in voltage-clamped myocytes. Intracellular cAMP levels were determined with an enzyme immunoassay; phosphodiesterase (PDE) and adenylyl cyclase (AC) isoform expression was examined with qPCR. Ca2+ currents were similar in myocytes from sham and OVX mice but Ca2+ transients, excitation-contraction (EC)-coupling gain, SR content and contractions were larger in OVX than sham cells. To determine if the cAMP/PKA pathway mediated OVX-induced alterations in EC-coupling, cardiomyocytes were incubated with the PKA inhibitor H-89 (2μM), which abolished baseline differences. While basal intracellular cAMP did not differ, levels were higher in OVX than sham in the presence of a non-selective PDE inhibitor (300μM IBMX), or an AC activator (10μM forskolin). This suggests the production of cAMP by AC and its breakdown by PDE were enhanced by OVX. Consistent with this, mRNA levels for both AC5 and PDE4A were higher in OVX in comparison to sham. Differences in Ca2+ homeostasis and contractions were abolished when sham and OVX cells were dialyzed with patch pipettes containing the same concentration of 8-bromoadenosine-cAMP (50μM). Interestingly, selective inhibition of PDE4 increased Ca2+ current only in OVX cells. Together, these findings suggest that estrogen suppresses SR Ca2+ release and that this is regulated, at least in part, by the cAMP/PKA pathway. These changes in the cAMP/PKA pathway may promote Ca2+ dysregulation and cardiovascular disease when ovarian estrogen levels fall. These results advance our understanding of female-specific cardiomyocyte mechanisms that may affect responses to therapeutic interventions in older women.
Collapse
Affiliation(s)
- Randi J Parks
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Oleg Bogachev
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Martin Mackasey
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Gibanananda Ray
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Robert A Rose
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Susan E Howlett
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada; Department of Medicine (Geriatric Medicine), Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| |
Collapse
|
8
|
Eschenhagen T. PDE4 in the human heart - major player or little helper? Br J Pharmacol 2014; 169:524-7. [PMID: 23489196 DOI: 10.1111/bph.12168] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 02/25/2013] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED PDEs restrict the positive inotropic effects of β-adrenoceptor stimulation by degrading cAMP. Hence, PDE inhibitors sensitize the heart to catecholamines and are therefore used as positive inotropes. On the downside, this is accompanied by exaggerated energy expenditure, cell death and arrhythmias. For many years, PDE3 was considered to be the major isoform responsible for the control of cardiac force and rhythm. However, recent work in gene-targeted mice and rodent cells has indicated that PDE4 is also involved. Furthermore, selective PDE4 inhibitors augment catecholamine-stimulated cAMP levels and induce arrhythmias in human atrial preparations, which suggests that PDE4 has a more prominent role in the human heart than anticipated, and that PDE4 inhibitors such as roflumilast may carry an arrhythmogenic risk. In this issue of the journal, a team of researchers from three laboratories report on the effect of PDE3 and PDE4 inhibitors on ventricular trabeculae from explanted human hearts. The key result is that the PDE4 inhibitor rolipram does not affect the positive inotropic effects of β₁ - or β₂ -adrenoceptor stimulation. Given that the ventricle rather than the atria is the critical region in terms of arrhythmogenic consequences, this is an important and reassuring finding. LINKED ARTICLE This article is a commentary on the research paper by Molenaar et al., pp. 528-538 of this issue. To view this paper visit http://dx.doi.org/10.1111/bph.12167.
Collapse
Affiliation(s)
- Thomas Eschenhagen
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg Eppendorf, Germany.
| |
Collapse
|
9
|
Mika D, Bobin P, Pomérance M, Lechêne P, Westenbroek RE, Catterall WA, Vandecasteele G, Leroy J, Fischmeister R. Differential regulation of cardiac excitation-contraction coupling by cAMP phosphodiesterase subtypes. Cardiovasc Res 2013; 100:336-46. [PMID: 23933582 DOI: 10.1093/cvr/cvt193] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Multiple phosphodiesterases (PDEs) hydrolyze cAMP in cardiomyocytes, but the functional significance of this diversity is not well understood. Our goal here was to characterize the involvement of three different PDEs (PDE2-4) in cardiac excitation-contraction coupling (ECC). METHODS AND RESULTS Sarcomere shortening and Ca(2+) transients were recorded simultaneously in adult rat ventricular myocytes and ECC protein phosphorylation by PKA was determined by western blot analysis. Under basal conditions, selective inhibition of PDE2 or PDE3 induced a small but significant increase in Ca(2+) transients, sarcomere shortening, and troponin I phosphorylation, whereas PDE4 inhibition had no effect. PDE3 inhibition, but not PDE2 or PDE4, increased phospholamban phosphorylation. Inhibition of either PDE2, 3, or 4 increased phosphorylation of the myosin-binding protein C, but neither had an effect on L-type Ca(2+) channel or ryanodine receptor phosphorylation. Dual inhibition of PDE2 and PDE3 or PDE2 and PDE4 further increased ECC compared with individual PDE inhibition, but the most potent combination was obtained when inhibiting simultaneously PDE3 and PDE4. This combination also induced a synergistic induction of ECC protein phosphorylation. Submaximal β-adrenergic receptor stimulation increased ECC, and this effect was potentiated by individual PDE inhibition with the rank order of potency PDE4 = PDE3 > PDE2. Identical results were obtained on ECC protein phosphorylation. CONCLUSION Our results demonstrate that PDE2, PDE3, and PDE4 differentially regulate ECC in adult cardiomyocytes. PDE2 and PDE3 play a more prominent role than PDE4 in regulating basal cardiac contraction and Ca(2+) transients. However, PDE4 becomes determinant when cAMP levels are elevated, for instance, upon β-adrenergic stimulation or PDE3 inhibition.
Collapse
|
10
|
Demirel-Yilmaz E, Cenik B, Ozcan G, Derici MK. Various phosphodiesterase activities in different regions of the heart alter the cardiac effects of nitric oxide. J Cardiovasc Pharmacol 2013; 60:283-92. [PMID: 22653417 DOI: 10.1097/fjc.0b013e31825f3eeb] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The modulation of cardiac functions by nitric oxide (NO) was established. This study examined the influences of phosphodiesterase (PDE) inhibitors on the action of NO in the different regions of the rat heart. NO donor diethylamine nonoate (DEA/NO) (0.1-100 μM) decreased functions of the right atrium. DEA/NO-induced depression of the developed tension of the right atrium was inhibited by [erythro-9-(2-hydroxy-3-nonyl)adenine] (PDE2 inhibitor), augmented by milrinone (PDE3 inhibitor), and upturned by rolipram (PDE4 inhibitor). A DEA/NO-induced decrease in the resting tension was inhibited by vinpocetine (PDE1 inhibitor) and [erythro-9-(2-hydroxy-3-nonyl)adenine] but reversed by rolipram. The decreased sinus rate by DEA/NO was prevented by vinpocetine and rolipram. DEA/NO increased cyclic guanosine monophosphate and cyclic adenosine monophosphate (cAMP) concentrations in the right atrium, and rolipram enhanced increased cAMP level. DEA/NO had no effect on the contraction of the papillary muscle. However, unchanged contraction under DEA/NO stimulation was decreased by vinpocetine, milrinone, and rolipram. DEA/NO increased cyclic guanosine monophosphate concentration but has no effect on cAMP in the papillary muscle. However, in the presence of vinpocetine and milrinone, DEA/NO reduced cAMP level. The PDE5 inhibitor sildenafil has no effect on DEA/NO actions. This study indicates that a variety of PDE activities in different regions of the rat heart shapes the action of NO on the myocardium.
Collapse
Affiliation(s)
- Emine Demirel-Yilmaz
- Department of Medical Pharmacology, Faculty of Medicine, Ankara University, Sihhiye, Ankara, Turkey.
| | | | | | | |
Collapse
|
11
|
Leroy J, Richter W, Mika D, Castro LRV, Abi-Gerges A, Xie M, Scheitrum C, Lefebvre F, Schittl J, Mateo P, Westenbroek R, Catterall WA, Charpentier F, Conti M, Fischmeister R, Vandecasteele G. Phosphodiesterase 4B in the cardiac L-type Ca²⁺ channel complex regulates Ca²⁺ current and protects against ventricular arrhythmias in mice. J Clin Invest 2011; 121:2651-61. [PMID: 21670503 DOI: 10.1172/jci44747] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 04/20/2011] [Indexed: 11/17/2022] Open
Abstract
β-Adrenergic receptors (β-ARs) enhance cardiac contractility by increasing cAMP levels and activating PKA. PKA increases Ca²⁺-induced Ca²⁺ release via phosphorylation of L-type Ca²⁺ channels (LTCCs) and ryanodine receptor 2. Multiple cyclic nucleotide phosphodiesterases (PDEs) regulate local cAMP concentration in cardiomyocytes, with PDE4 being predominant for the control of β-AR-dependent cAMP signals. Three genes encoding PDE4 are expressed in mouse heart: Pde4a, Pde4b, and Pde4d. Here we show that both PDE4B and PDE4D are tethered to the LTCC in the mouse heart but that β-AR stimulation of the L-type Ca²⁺ current (ICa,L) is increased only in Pde4b-/- mice. A fraction of PDE4B colocalized with the LTCC along T-tubules in the mouse heart. Under β-AR stimulation, Ca²⁺ transients, cell contraction, and spontaneous Ca²⁺ release events were increased in Pde4b-/- and Pde4d-/- myocytes compared with those in WT myocytes. In vivo, after intraperitoneal injection of isoprenaline, catheter-mediated burst pacing triggered ventricular tachycardia in Pde4b-/- mice but not in WT mice. These results identify PDE4B in the CaV1.2 complex as a critical regulator of ICa,L during β-AR stimulation and suggest that distinct PDE4 subtypes are important for normal regulation of Ca²⁺-induced Ca²⁺ release in cardiomyocytes.
Collapse
|
12
|
Conserved expression and functions of PDE4 in rodent and human heart. Basic Res Cardiol 2010; 106:249-62. [PMID: 21161247 PMCID: PMC3032896 DOI: 10.1007/s00395-010-0138-8] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 11/17/2010] [Accepted: 12/01/2010] [Indexed: 01/21/2023]
Abstract
PDE4 isoenzymes are critical in the control of cAMP signaling in rodent cardiac myocytes. Ablation of PDE4 affects multiple key players in excitation–contraction coupling and predisposes mice to the development of heart failure. As little is known about PDE4 in human heart, we explored to what extent cardiac expression and functions of PDE4 are conserved between rodents and humans. We find considerable similarities including comparable amounts of PDE4 activity expressed, expression of the same PDE4 subtypes and splicing variants, anchoring of PDE4 to the same subcellular compartments and macromolecular signaling complexes, and downregulation of PDE4 activity and protein in heart failure. The major difference between the species is a fivefold higher amount of non-PDE4 activity in human hearts compared to rodents. As a consequence, the effect of PDE4 inactivation is different in rodents and humans. PDE4 inhibition leads to increased phosphorylation of virtually all PKA substrates in mouse cardiomyocytes, but increased phosphorylation of only a restricted number of proteins in human cardiomyocytes. Our findings suggest that PDE4s have a similar role in the local regulation of cAMP signaling in rodent and human heart. However, inhibition of PDE4 has ‘global’ effects on cAMP signaling only in rodent hearts, as PDE4 comprises a large fraction of the total cardiac PDE activity in rodents but not in humans. These differences may explain the distinct pharmacological effects of PDE4 inhibition in rodent and human hearts.
Collapse
|
13
|
Terrenoire C, Houslay MD, Baillie GS, Kass RS. The cardiac IKs potassium channel macromolecular complex includes the phosphodiesterase PDE4D3. J Biol Chem 2009; 284:9140-6. [PMID: 19218243 DOI: 10.1074/jbc.m805366200] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cardiac I(Ks) potassium channel is a macromolecular complex consisting of alpha-(KCNQ1) and beta-subunits (KCNE1) and the A kinase-anchoring protein (AKAP) Yotiao (AKAP-9), which recruits protein kinase A) and protein phosphatase 1 to the channel. Here, we have tested the hypothesis that specific cAMP phosphodiesterase (PDE) isoforms of the PDE4D family that are expressed in the heart are also part of the I(Ks) signaling complex and contribute to its regulation by cAMP. PDE4D isoforms co-immunoprecipitated with I(Ks) channels in hearts of mice expressing the I(Ks) channel. In myocytes isolated from these mice, I(Ks) was increased by pharmacological PDE inhibition. PDE4D3, but not PDE4D5, co-immunoprecipitated with the I(Ks) channel only in Chinese hamster ovary cells co-expressing AKAP-9, and PDE4D3, but not PDE4D5, co-immunoprecipitated with AKAP-9. Functional experiments in Chinese hamster ovary cells expressing AKAP-9 and either PDE4D3 or PDE4D5 isoforms revealed modulation of the I(Ks) response to cAMP by PDE4D3 but not PDE4D5. We conclude that PDE4D3, like protein kinase A and protein phosphatase 1, is recruited to the I(Ks) channel via AKAP-9 and contributes to its critical regulation by cAMP.
Collapse
Affiliation(s)
- Cecile Terrenoire
- Department of Pharmacology, Columbia University Medical Center, New York, New York 10032, USA
| | | | | | | |
Collapse
|
14
|
Rao YJ, Xi L. Pivotal effects of phosphodiesterase inhibitors on myocyte contractility and viability in normal and ischemic hearts. Acta Pharmacol Sin 2009; 30:1-24. [PMID: 19060915 DOI: 10.1038/aps.2008.1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Phosphodiesterases (PDEs) are enzymes that degrade cellular cAMP and cGMP and are thus essential for regulating the cyclic nucleotides. At least 11 families of PDEs have been identified, each with a distinctive structure, activity, expression, and tissue distribution. The PDE type-3, -4, and -5 (PDE3, PDE4, PDE5) are localized to specific regions of the cardiomyocyte, such as the sarcoplasmic reticulum and Z-disc, where they are likely to influence cAMP/cGMP signaling to the end effectors of contractility. Several PDE inhibitors exhibit remarkable hemodynamic and inotropic properties that may be valuable to clinical practice. In particular, PDE3 inhibitors have potent cardiotonic effects that can be used for short-term inotropic support, especially in situations where adrenergic stimulation is insufficient. Most relevant to this review, PDE inhibitors have also been found to have cytoprotective effects in the heart. For example, PDE3 inhibitors have been shown to be cardioprotective when given before ischemic attack, whereas PDE5 inhibitors, which include three widely used erectile dysfunction drugs (sildenafil, vardenafil and tadalafil), can induce remarkable cardioprotection when administered either prior to ischemia or upon reperfusion. This article provides an overview of the current laboratory and clinical evidence, as well as the cellular mechanisms by which the inhibitors of PDE3, PDE4 and PDE5 exert their beneficial effects on normal and ischemic hearts. It seems that PDE inhibitors hold great promise as clinically applicable agents that can improve cardiac performance and cell survival under critical situations, such as ischemic heart attack, cardiopulmonary bypass surgery, and heart failure.
Collapse
|
15
|
MESH Headings
- Adrenergic beta-Agonists/pharmacology
- Animals
- Biosensing Techniques
- Calcium Channels, L-Type/metabolism
- Cyclic AMP/metabolism
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Cyclic Nucleotide Phosphodiesterases, Type 3/metabolism
- Cyclic Nucleotide Phosphodiesterases, Type 4/metabolism
- Heart Ventricles/metabolism
- Kinetics
- Membrane Potentials
- Myocardial Contraction/drug effects
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/enzymology
- Myocytes, Cardiac/metabolism
- Phosphodiesterase 3 Inhibitors
- Phosphodiesterase 4 Inhibitors
- Phosphodiesterase Inhibitors/pharmacology
- Phosphorylation
- Rats
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/metabolism
- Signal Transduction/drug effects
Collapse
|
16
|
Osadchii OE. Myocardial phosphodiesterases and regulation of cardiac contractility in health and cardiac disease. Cardiovasc Drugs Ther 2007; 21:171-94. [PMID: 17373584 DOI: 10.1007/s10557-007-6014-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Accepted: 02/21/2007] [Indexed: 01/14/2023]
Abstract
Phosphodiesterase (PDE) inhibitors are potent cardiotonic agents used for parenteral inotropic support in heart failure. Contractile effects of these agents are mediated through cAMP-protein kinase A-induced stimulation of I (Ca2+) which ultimately results in increased Ca(2+)-induced sarcoplasmic reticulum Ca(2+) release. A number of additional effects such as increases in sarcoplasmic reticulum Ca(2+) stores, stimulation of reverse mode Na(+)-Ca(2+) exchange, direct or cAMP-mediated effects on sarcoplasmic reticulum ryanodine receptor, stimulation of the voltage-sensitive sarcoplasmic reticulum Ca(2+) release mechanism, as well as A(1) adenosine receptor blockade could contribute to positive inotropic responses to PDE inhibitors. Moreover, some PDE inhibitors exhibit Ca(2+) sensitizer properties as they could increase the affinity of troponin C Ca(2+)-binding sites as well as reduce Ca(2+) threshold for thin myofilament sliding and facilitate cross-bridge cycling. Inotropic responses to PDE inhibitors are significantly reduced in cardiac disease, an effect largely attributed to downregulation of cAMP-mediated signalling due to sustained sympathetic activation. Four PDE isoenzymes (PDE1, PDE2, PDE3 and PDE4) are present in myocardial tissue of various mammalian species, of which PDE3 and PDE4 are particularly involved in regulation of cardiac myocyte contraction. PDE cAMP-hydrolysing activity is preserved in compensated cardiac hypertrophy but significantly reduced in animal models of heart failure. However, clinical studies have not revealed any changes in distribution profile as well as kinetic and regulatory properties of myocardial PDEs in failing human hearts. A reduction of PDE inhibitors-induced contractile responses in heart failure has therefore been ascribed to reduced cAMP synthesis due to uncoupling of adenylyl cyclase from beta-adrenoreceptor. In cardiac myocytes, PDEs are targeted to distinct subcellular compartments by scaffolding proteins such as myomegalin, mAKAP and beta-arrestins. Over subcellular microdomains, cAMP hydrolysis by PDE3 and PDE4 allows to control the activity of local pools of protein kinase A and therefore the extent of protein kinase A-mediated phosphorylation of cellular proteins.
Collapse
Affiliation(s)
- Oleg E Osadchii
- Cardiology Group, School of Clinical Sciences, University Clinical Departments, University of Liverpool, The Duncan Building, Liverpool, UK.
| |
Collapse
|
17
|
Christ T, Engel A, Ravens U, Kaumann AJ. Cilostamide potentiates more the positive inotropic effects of (-)-adrenaline through beta(2)-adrenoceptors than the effects of (-)-noradrenaline through beta (1)-adrenoceptors in human atrial myocardium. Naunyn Schmiedebergs Arch Pharmacol 2006; 374:249-53. [PMID: 17106669 DOI: 10.1007/s00210-006-0119-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Accepted: 10/28/2006] [Indexed: 10/23/2022]
Abstract
Activation of both beta(1)- and beta(2)-adrenoceptors increases the contractility of human atrial myocardium through cyclic AMP-dependent pathways. Cyclic AMP is hydrolised by phosphodiesterases, but little is known about which isoenzymes catalyse inotropically relevant cyclic AMP accumulated upon stimulation of beta-adrenoceptor subtypes. We have compared the positive inotropic effects of (-)-noradrenaline and (-)-adrenaline, mediated through beta(1)- and beta(2)-adrenoceptors, respectively, in the absence and presence of the PDE3 inhibitor cilostamide (300 nM) or PDE4 inhibitor rolipram (1 muM) on human atrial trabeculae from non-failing hearts. Cilostamide, but not rolipram, potentiated the effects of both (-)-noradrenaline and (-)-adrenaline. Cilostamide increased the -logEC(50)M of (-)-adrenaline more than of (-)-noradrenaline (P < 0.05), regardless of whether or not the patients had been chronically treated with beta-blockers. The results are consistent with a greater PDE3-catalysed hydrolysis of inotropically relevant cyclic AMP produced through beta(2)-adrenoceptors than beta(1)-adrenoceptors in human atrium.
Collapse
MESH Headings
- 3',5'-Cyclic-AMP Phosphodiesterases/metabolism
- Adrenergic beta-Antagonists
- Aged
- Cyclic AMP/metabolism
- Cyclic Nucleotide Phosphodiesterases, Type 3
- Cyclic Nucleotide Phosphodiesterases, Type 4
- Dose-Response Relationship, Drug
- Epinephrine/pharmacology
- Female
- Heart Atria/drug effects
- Humans
- Hydrolysis
- In Vitro Techniques
- Male
- Middle Aged
- Myocardial Contraction/drug effects
- Myocardium
- Norepinephrine/pharmacology
- Phosphodiesterase Inhibitors/pharmacology
- Quinolones/pharmacology
- Receptors, Adrenergic, beta-1/drug effects
- Receptors, Adrenergic, beta-1/metabolism
- Receptors, Adrenergic, beta-2/drug effects
- Receptors, Adrenergic, beta-2/metabolism
- Rolipram/pharmacology
Collapse
Affiliation(s)
- T Christ
- Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany,
| | | | | | | |
Collapse
|
18
|
Lourenco CM, Kenk M, Beanlands RS, DaSilva JN. Increasing synaptic noradrenaline, serotonin and histamine enhances in vivo binding of phosphodiesterase-4 inhibitor (R)-[11C]rolipram in rat brain, lung and heart. Life Sci 2006; 79:356-64. [PMID: 16499932 DOI: 10.1016/j.lfs.2006.01.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Revised: 12/22/2005] [Accepted: 01/11/2006] [Indexed: 10/25/2022]
Abstract
Phosphodiesterase-4 (PDE4) is one of the main enzymes that specifically terminate the action of cAMP, thereby contributing to intracellular signaling following stimulation of various G protein-coupled receptors. PDE4 expression and activity are modulated by agents affecting cAMP levels. The selective PDE4 inhibitor (R)-rolipram labeled with C-11 was tested in vivo in rats to analyze changes in PDE4 levels following drug treatments that increase synaptic noradrenaline (NA), serotonin (5HT), histamine (HA) and dopamine (DA) levels. We hypothesized that increasing synaptic neurotransmitter levels and subsequent cAMP-mediated signaling would significantly enhance (R)-[(11)C]rolipram retention and specific binding to PDE4 in vivo. Pre-treatments were performed 3 h prior to tracer injection, and rats were sacrificed 45 min later. Biodistribution studies revealed a dose-dependent increase in (R)-[(11)C]rolipram uptake following administration of the monoamine oxidase (MAO) inhibitor tranylcypromine, NA and 5HT reuptake inhibitors (desipramine [DMI], maprotiline; and fluoxetine, sertraline, respectively), and the HA H(3) receptor antagonist (thioperamide), but not with DA transporter blockers GBR 12909, cocaine or DA D(1) agonist SKF81297. Significant increases in rat brain and heart reflect changes in PDE4 specific binding (total-non-specific binding [coinjection with saturating dose of (R)-rolipram]). These results demonstrate that acute treatments elevating synaptic NA, 5HT and HA, but not DA levels, significantly enhance (R)-[(11)C]rolipram binding. Use of (R)-[(11)C]rolipram and positron emission tomography as an index of PDE4 activity could provide insight into understanding disease states with altered NA, 5HT and HA concentrations.
Collapse
Affiliation(s)
- Celia M Lourenco
- PET Centre, Centre for Addiction and Mental Health, 250 College St., Toronto, Ontario, Canada M5T 1R8
| | | | | | | |
Collapse
|
19
|
Dietsch GN, Dipalma CR, Eyre RJ, Pham TQ, Poole KM, Pefaur NB, Welch WD, Trueblood E, Kerns WD, Kanaly ST. Characterization of the inflammatory response to a highly selective PDE4 inhibitor in the rat and the identification of biomarkers that correlate with toxicity. Toxicol Pathol 2006; 34:39-51. [PMID: 16507543 DOI: 10.1080/01926230500385549] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The primary toxicity associated with repeated oral administration of the PDE4 inhibitor IC542 to the rat is an inflammatory response leading to tissue damage primarily in the gastrointestinal tract and mesentery. Although necrotizing vasculitis is frequently seen with other PDE4 inhibitors, blood vessel injury was rare following IC542 administration and was always associated with inflammation in the surrounding tissue. The incidence and severity of the histologic changes in these studies correlated with elevated peripheral blood leukocytes, serum IL-6, haptoglobin, and fibrinogen, and with decreased serum albumin. By monitoring haptoglobin, fibrinogen and serum albumin changes in IC542-treated rats, it was possible to identify rats with early histologic changes that were reversible. Since PDE4 inhibition is generally associated with anti-inflammatory activity, extensive inflammation in multiple tissues was unexpected with IC542. Co-administration of dexamethasone completely blocked IC542-induced clinical and histologic changes in the rat, confirming the toxicity resulted from inflammatory response. In addition, IC542 augmented release of the proinflammatory cytokine IL-6 in LPS-activated whole blood from rats but not monkeys or humans. The effect of IC542 on IL-6 release from rat leukocytes in vitro is consistent with the proinflammatory response observed in vivo and demonstrates species differences to PDE4 inhibition.
Collapse
|
20
|
Osadchii O, Norton G, Woodiwiss A. Inotropic responses to phosphodiesterase inhibitors in cardiac hypertrophy in rats. Eur J Pharmacol 2005; 514:201-8. [PMID: 15910807 DOI: 10.1016/j.ejphar.2005.03.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 03/07/2005] [Accepted: 03/16/2005] [Indexed: 11/28/2022]
Abstract
In the present study we sought to determine whether reduced contractile responses to phosphodiesterase inhibitors occur in the face of chronic cardiac hypertrophy associated with beta-adrenergic inotropic downregulation. As compared to age-matched Wistar-Kyoto control rats, spontaneously hypertensive rats at 6-8 months of age exhibited a striking decrease in left ventricular inotropic responses induced by isoproterenol, a beta-adrenoceptor agonist, in isolated, isovolumically contracting heart preparations. Despite profound beta-adrenoceptor-mediated inotropic downregulation, similar contractile responses to the phosphodiesterase III selective inhibitors, amrinone and milrinone, the phosphodiesterase IV selective inhibitor, rolipram, and non-selective phosphodiesterase inhibitor, pentoxifylline, were detected in normal and hypertrophic heart preparations. Moreover, the inotropic potency of the cAMP analogue, 8-Br-cAMP, was increased in spontaneously hypertensive rats. These findings suggest that in chronic cardiac hypertrophy, contractile responses to phosphodiesterase inhibitors may be preserved despite marked reductions in inotropic responses to beta-adrenoceptor agonists.
Collapse
Affiliation(s)
- Oleg Osadchii
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, University of the Witwatersrand Medical School, 7 York Road, Parktown, Johannesburg 2193, South Africa.
| | | | | |
Collapse
|
21
|
Weiss HR, Lazar MJ, Punjabi K, Tse J, Scholz PM. Negative functional effects of cyclic GMP are altered by cyclic AMP phosphodiesterases in rabbit cardiac myocytes. Eur J Pharmacol 2004; 481:25-31. [PMID: 14637171 DOI: 10.1016/j.ejphar.2003.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study, we tested the hypothesis that the negative functional effects of cyclic GMP on cardiac myocytes would be affected by the actions of cyclic GMP on cyclic AMP phosphodiesterases. Ventricular myocytes from eight rabbits were used to determine the functional and cyclic AMP changes caused by 10(-7), 10(-6), 10(-5) M 8-Bromo-cGMP alone and after the administration of 10(-6) M milrinone (cyclic GMP-inhibited cyclic AMP phosphodiesterase inhibitor) or 10(-6) M erythro-9-(2-Hydroxy-3-3-nonyl)adenine (EHNA, cyclic GMP-stimulated cyclic AMP phosphodiesterase inhibitor). 8-Br-cGMP dose-dependently reduced %shortening by 35+/-4% of baseline at 10(-5) M. This effect was significantly blunted by EHNA at all doses. The maximum rate of shortening was reduced by 31+/-3% by 10(-5) M 8-Br-cGMP. This effect of 8-Br-cGMP was significantly enhanced (42+/-4%) in the milrinone group. A similar pattern was observed in the maximum rate of relaxation data. Cyclic AMP levels were significantly increased from a baseline level of 4.0+/-0.8 pmol/10(5) myocytes by milrinone (+60%), EHNA (+61%) and 8-Br-cGMP (+47%). The combination of EHNA plus 8-Br-cGMP increased cyclic AMP levels significantly more that the combination of milrinone plus 8-Br-cGMP. Exogenous cyclic GMP reduces myocyte function, while raising cyclic AMP possibly through cyclic GMP-inhibited cyclic AMP phosphodiesterase effects. Blocking cyclic GMP-inhibited cyclic AMP phosphodiesterase enhances the functional effects cyclic GMP, while blocking cyclic GMP-stimulated cyclic AMP phosphodiesterase reduced these effects. The study demonstrated a functional interaction between cyclic GMP and cyclic AMP related to the cyclic GMP affected cyclic AMP phosphodiesterases.
Collapse
Affiliation(s)
- Harvey R Weiss
- Heart and Brain Circulation Laboratory, Department of Physiology and Biophysics, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854-5635, USA.
| | | | | | | | | |
Collapse
|
22
|
Cui X, Wen JF, Jin H, Li D, Jin JY, Kim SH, Kim SZ, Lee HS, Cho KW. Subtype-specific roles of cAMP phosphodiesterases in regulation of atrial natriuretic peptide release. Eur J Pharmacol 2003; 451:295-302. [PMID: 12242091 DOI: 10.1016/s0014-2999(02)02294-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
cAMP is known to control the release of atrial natriuretic peptide. To define the roles of cyclic nucleotide phosphodiesterase subtypes in the regulation of atrial natriuretic peptide (ANP) release, experiments were done with perfused beating rabbit atria. Phosphodiesterase 3 subtype-specific inhibitors, milrinone and cilostamide, inhibited myocytic ANP release with a concomitant increase in cAMP efflux. Similarly, trequinsin, another phosphodiesterase 3 inhibitor, decreased ANP release. A phosphodiesterase 4 subtype-specific inhibitor, rolipram, did not significantly change ANP release but increased AMP efflux. Also, 4-[(3-butoxy-4-methoxyphenyl)methyl]-2-imidazolidinone (Ro 20-1724), another phosphodiesterase 4 inhibitor, did not significantly change ANP release. The cAMP efflux was higher in the atrium treated with rolipram than in the atrium treated with milrinone or cilostamide. The data show that the cAMP pool, which is metabolized by phosphodiesterase 3, but not phosphodiesterase 4, is closely related to the basal regulation of atrial ANP release. The results suggest that intracellular cAMP is compartmentalized in the regulation of atrial ANP release, and that the release is controlled by a phosphodiesterase subtype-specific mechanism.
Collapse
Affiliation(s)
- Xun Cui
- Department of Physiology, Medical School, Institute for Medical Sciences, Jeonbug National University, Jeonju 561-180, South Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Ziolo MT, Lewandowski SJ, Smith JM, Romano FD, Wahler GM. Inhibition of cyclic GMP hydrolysis with zaprinast reduces basal and cyclic AMP-elevated L-type calcium current in guinea-pig ventricular myocytes. Br J Pharmacol 2003; 138:986-94. [PMID: 12642401 PMCID: PMC1573723 DOI: 10.1038/sj.bjp.0705112] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
(1) Cyclic GMP (cGMP) has been shown to be an important modulator of cardiac contractile function. A major component of cGMP regulation of contractility is cGMP-mediated inhibition of the cardiac calcium current (I(Ca)). An under-appreciated aspect of cyclic nucleotide signalling is hydrolysis of the cyclic nucleotide (i.e., breakdown by phosphodiesterases (PDEs)). The role of cGMP hydrolysis in regulating I(Ca) has not been studied. Thus the purpose of this study was to investigate if inhibition of cGMP hydrolysis can modulate I(Ca) in isolated guinea-pig ventricular myocytes. (2) Zaprinast, a selective inhibitor of cGMP-specific PDE (PDE5), caused a significant increase in cGMP levels in myocytes, but was without affect on basal or beta-adrenergic stimulated cAMP levels (consistent with its actions as a specific inhibitor of PDE5). (3) Zaprinast inhibited I(Ca) that was pre-stimulated with cAMP elevating agents (isoproterenol, a beta-adrenergic agonist; or forskolin, a direct activator of adenylate cyclase). The effect of zaprinast was greatly reduced by KT5823, an inhibitor of cGMP-dependent protein kinase (PKG). (4) Zaprinast also significantly inhibited basal I(Ca) when perforated-patch or whole-cell recording with physiological pipette calcium concentration (10(-7) M) was used. However, this effect was not observed when using standard calcium-free whole-cell recording conditions. (5) These results indicate that inhibition of cGMP hydrolysis can decrease both basal and cAMP-stimulated I(Ca). Thus, cGMP hydrolysis may likely be an important step for physiological modulation of I(Ca). This regulation may also be important in disease states in which cGMP production is increased and PDE5 expression is altered, such as heart failure.
Collapse
Affiliation(s)
- Mark T Ziolo
- Department of Physiology, Midwestern University, 555 31st Street, Downers Grove, Illinois, IL 60515 U.S.A
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, IL 60612, U.S.A
| | - Susanne J Lewandowski
- Department of Physiology, Midwestern University, 555 31st Street, Downers Grove, Illinois, IL 60515 U.S.A
| | - Jacquelyn M Smith
- Department of Physiology, Midwestern University, 555 31st Street, Downers Grove, Illinois, IL 60515 U.S.A
| | - Fred D Romano
- Department of Physiology, Midwestern University, 555 31st Street, Downers Grove, Illinois, IL 60515 U.S.A
| | - Gordon M Wahler
- Department of Physiology, Midwestern University, 555 31st Street, Downers Grove, Illinois, IL 60515 U.S.A
- Author for correspondence:
| |
Collapse
|
24
|
Ajiro Y, Hagiwara N, Katsube Y, Sperelakis N, Kasanuki H. Levosimendan increases L-type Ca(2+) current via phosphodiesterase-3 inhibition in human cardiac myocytes. Eur J Pharmacol 2002; 435:27-33. [PMID: 11790375 DOI: 10.1016/s0014-2999(01)01569-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To evaluate the potency of levosimendan, a newly developed cardiotonic agent, as a phosphodiesterase-3 inhibitor, we examined its effects on the L-type Ca(2+) current (I(Ca,L)) in single human atrial cells using the whole-cell voltage-clamp method. Levosimendan significantly increased I(Ca,L) in a concentration-dependent manner (E(max), 139.0 +/- 1.8%; EC(50), 54 +/- 3.6 nM). The increase in I(Ca,L) induced by 1 microM levosimendan was significantly greater in human atrial cells (136.7 +/- 11.0%, n=8) than in rabbit atrial cells (23.5 +/- 3.5%, n=6) (depolarization to +10 mV in each case). In rat atrial and ventricular cells, I(Ca,L) was unaffected by 1-10 microM levosimendan. These results indicate that the selective phosphodiesterase-3 inhibitor levosimendan increases cardiac-cell I(Ca,L) significantly more strongly in human than in rabbit and rat. It seems likely that the positive inotropic effect of levosimendan on the human myocardium depends on an increase in I(Ca,L) that is modulated by adenosine 3'5'-cyclic monophosphate (cAMP)-dependent phosphorylation.
Collapse
Affiliation(s)
- Youichi Ajiro
- The Heart Institute of Japan, Tokyo Women's Medical University, 8-1 Kawada-cho, Tokyo 162-8666, Shinjuku, Japan
| | | | | | | | | |
Collapse
|
25
|
Abstract
A novel benzopyran derivative, NIP-141, effectively terminates experimental atrial fibrillation in canine hearts by prolonging atrial refractoriness. However, the effects of this drug on human atrial myocytes are unknown. This experiment evaluated the effects of NIP-141 on K currents in isolated human atrial myocytes using a whole-cell voltage-clamp method. NIP-141 inhibited the transient outward current (I(to)) and the ultra-rapid delayed rectifier K current (I(Kur)), each in a dose-dependent manner, with half-maximal inhibition concentrations of 16.3 microM and 5.3 microM, respectively (n = 5). NIP-141 inhibited both K currents in a voltage- and use-independent fashion, and it preferentially blocked them in the open state and dissociated rapidly from the channel. Because both K currents contribute significantly to the repolarization of the atrial action potential, these findings suggest that NIP-141 may terminate atrial fibrillation by prolonging action potential duration.
Collapse
Affiliation(s)
- Akiko Seki
- The Heart Institute of Japan, Tokyo Women's Medical University, Tokyo, Japan
| | | | | |
Collapse
|
26
|
Vandecasteele G, Verde I, Rücker-Martin C, Donzeau-Gouge P, Fischmeister R. Cyclic GMP regulation of the L-type Ca(2+) channel current in human atrial myocytes. J Physiol 2001; 533:329-40. [PMID: 11389195 PMCID: PMC2278627 DOI: 10.1111/j.1469-7793.2001.0329a.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
1. The regulation of the L-type Ca(2+) current (I(Ca)) by intracellular cGMP was investigated in human atrial myocytes using the whole-cell patch-clamp technique. 2. Intracellular application of 0.5 microM cGMP produced a strong stimulation of basal I(Ca) (+64 +/- 5 %, n = 60), whereas a 10-fold higher cGMP concentration induced a 2-fold smaller increase (+36 +/- 8 %, n = 35). 3. The biphasic response of I(Ca) to cGMP was not mimicked by the cGMP-dependent protein kinase (PKG) activator 8-bromoguanosine 3',5' cyclic monophosphate (8-bromo-cGMP, 0.5 or 5 microM), and was not affected by the PKG inhibitor KT 5823 (100 nM). 4. In contrast, cGMP stimulation of I(Ca) was abolished by intracellular perfusion with PKI (10 microM), a selective inhibitor of the cAMP-dependent protein kinase (PKA). 5. Selective inhibition of the cGMP-inhibited phosphodiesterase (PDE3) by extracellular cilostamide (100 nM) strongly enhanced basal I(Ca) in control conditions (+78 +/- 13 %, n = 7) but had only a marginal effect in the presence of intracellular cGMP (+22 +/- 7 % in addition to 0.5 microM cGMP, n = 11; +20 +/- 22 % in addition to 5 microM cGMP, n = 7). 6. Application of erythro-9-[2-hydroxy-3-nonyl]adenine (EHNA, 30 microM), a selective inhibitor of the cGMP-stimulated phosphodiesterase (PDE2), fully reversed the secondary inhibitory effect of 5 microM cGMP on I(Ca) (+99 +/- 16 % stimulation, n = 7). 7. Altogether, these data indicate that intracellular cGMP regulates basal I(Ca) in human atrial myocytes in a similar manner to NO donors. The effect of cGMP involves modulation of the cAMP level and PKA activity via opposite actions of the nucleotide on PDE2 and PDE3.
Collapse
Affiliation(s)
- G Vandecasteele
- Laboratoire de Cardiologie Cellulaire et Moléculaire, INSERM U-446, Université de Paris-Sud, Faculté de Pharmacie, F-92296 Châtenay-Malabry, France
| | | | | | | | | |
Collapse
|
27
|
Movsesian MA. Therapeutic potential of cyclic nucleotide phosphodiesterase inhibitors in heart failure. Expert Opin Investig Drugs 2000; 9:963-73. [PMID: 11060720 DOI: 10.1517/13543784.9.5.963] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
There are several reasons to believe that agents that augment cAMP-mediated signalling in cardiac myocytes should have beneficial effects in patients with heart failure. However, clinical trials of first-generation cyclic nucleotide phosphodiesterase (PDE3) inhibitors, which raise cAMP content by blocking its hydrolysis, have shown that chronic administration of these drugs affect survival adversely. The problem may be the non-selective activation of a broad spectrum of cAMP-regulated cellular responses these agents elicit. More selective (or alternatively selective) cyclic nucleotide PDE inhibitors might improve results by evoking a more restricted set of cellular responses.
Collapse
Affiliation(s)
- M A Movsesian
- Cardiology Division, University of Utah Health Sciences Center, 50 North Medical Drive, Salt Lake City, UT 84132, USA.
| |
Collapse
|
28
|
Schudt C, Gantner F, Tenors H, Hatzelmann A. Therapeutic potential of selective PDE inhibitors in asthma. Pulm Pharmacol Ther 1999; 12:123-9. [PMID: 10373395 DOI: 10.1006/pupt.1999.0182] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- C Schudt
- Byk Gulden, Department of Biochemistry, D-78403 Konstanz, Germany
| | | | | | | |
Collapse
|
29
|
Verde I, Vandecasteele G, Lezoualc'h F, Fischmeister R. Characterization of the cyclic nucleotide phosphodiesterase subtypes involved in the regulation of the L-type Ca2+ current in rat ventricular myocytes. Br J Pharmacol 1999; 127:65-74. [PMID: 10369457 PMCID: PMC1565993 DOI: 10.1038/sj.bjp.0702506] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The effects of several phosphodiesterase (PDE) inhibitors on the L-type Ca current (I(Ca)) and intracellular cyclic AMP concentration ([cAMP]i) were examined in isolated rat ventricular myocytes. The presence of mRNA transcripts encoding for the different cardiac PDE subtypes was confirmed by RT-PCR. IBMX (100 microM), a broad-spectrum PDE inhibitor, increased basal I(Ca) by 120% and [cAMP]i by 70%, similarly to a saturating concentration of the beta-adrenoceptor agonist isoprenaline (1 microM). However, MIMX (1 microM), a PDE1 inhibitor, EHNA (10 microM), a PDE2 inhibitor, cilostamide (0.1 microM), a PDE3 inhibitor, or Ro20-1724 (0.1 microM), a PDE4 inhibitor, had no effect on basal I(Ca) and little stimulatory effects on [cAMP]i (20-30%). Each selective PDE inhibitor was then tested in the presence of another inhibitor to examine whether a concomitant inhibition of two PDE subtypes had any effect on I(Ca) or [cAMP]i. While all combinations tested significantly increased [cAMP]i (40-50%), only cilostamide (0.1 microM)+ Ro20-1724 (0.1 microM) produced a significant stimulation of I(Ca) (50%). Addition of EHNA (10 microM) to this mix increased I(Ca) to 110% and [cAMP]i to 70% above basal, i.e. to similar levels as obtained with IBMX (100 microM) or isoprenaline (1 microM). When tested on top of a sub-maximal concentration of isoprenaline (1 nM), which increased I(Ca) by (approximately 40% and had negligible effect on [cAMP]i, each selective PDE inhibitor induced a clear stimulation of [cAMP]i and an additional increase in I(Ca). Maximal effects on I(Ca) were approximately 8% for MIMX (3 microM), approximately 20% for EHNA (1-3 microM), approximately 30% for cilostamide (0.3-1 microM) and approximately 50% for Ro20-1724 (0.1 microM). Our results demonstrate that PDE1-4 subtypes regulate I(Ca) in rat ventricular myocytes. While PDE3 and PDE4 are the dominant PDE subtypes involved in the regulation of basal I(Ca), all four PDE subtypes determine the response of I(Ca) to a stimulus activating cyclic AMP production, with the rank order of potency PDE4>PDE3>PDE2>PDE1.
Collapse
MESH Headings
- 3',5'-Cyclic-AMP Phosphodiesterases/antagonists & inhibitors
- 3',5'-Cyclic-AMP Phosphodiesterases/biosynthesis
- 3',5'-Cyclic-AMP Phosphodiesterases/physiology
- 3',5'-Cyclic-GMP Phosphodiesterases/antagonists & inhibitors
- 3',5'-Cyclic-GMP Phosphodiesterases/biosynthesis
- 3',5'-Cyclic-GMP Phosphodiesterases/physiology
- Adrenergic beta-Agonists/pharmacology
- Animals
- Calcium/physiology
- Calcium Channels/metabolism
- Calcium Channels, L-Type
- Cyclic AMP/physiology
- Cyclic Nucleotide Phosphodiesterases, Type 1
- Cyclic Nucleotide Phosphodiesterases, Type 3
- Cyclic Nucleotide Phosphodiesterases, Type 4
- Heart Ventricles/cytology
- Heart Ventricles/enzymology
- Heart Ventricles/metabolism
- In Vitro Techniques
- Isoproterenol/pharmacology
- Male
- Myocardium/cytology
- Myocardium/enzymology
- Myocardium/metabolism
- Patch-Clamp Techniques
- Phosphodiesterase Inhibitors/pharmacology
- Phosphoric Diester Hydrolases
- Rats
- Rats, Wistar
- Reverse Transcriptase Polymerase Chain Reaction
Collapse
Affiliation(s)
- Ignacio Verde
- Laboratoire de Cardiologie Cellulaire et Moléculaire, INSERM U-446, Université de Paris-Sud, Faculté de Pharmacie, F-92296 Châtenay-Malabry, France
| | - Grégoire Vandecasteele
- Laboratoire de Cardiologie Cellulaire et Moléculaire, INSERM U-446, Université de Paris-Sud, Faculté de Pharmacie, F-92296 Châtenay-Malabry, France
| | - Frank Lezoualc'h
- Laboratoire de Cardiologie Cellulaire et Moléculaire, INSERM U-446, Université de Paris-Sud, Faculté de Pharmacie, F-92296 Châtenay-Malabry, France
| | - Rodolphe Fischmeister
- Laboratoire de Cardiologie Cellulaire et Moléculaire, INSERM U-446, Université de Paris-Sud, Faculté de Pharmacie, F-92296 Châtenay-Malabry, France
- Author for correspondence:
| |
Collapse
|
30
|
Seki A, Hagiwara N, Kasanuki H. Effects of propafenone on K currents in human atrial myocytes. Br J Pharmacol 1999; 126:1153-62. [PMID: 10205003 PMCID: PMC1565895 DOI: 10.1038/sj.bjp.0702428] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
1. The class Ic anti-arrhythmic agent, flecainide is known to inhibit the transient outward K current (Ito) selectively in human atrium. We studied the effects of propafenone, another class Ic antiarrhythmic agent, on K currents in human atrial myocytes using a whole-cell voltage-clamp method. 2. Propafenone inhibited both Ito and the sustained or ultra-rapid delayed rectifier K current (Isus or Ikur) evoked by depolarization pulses. The concentration for half-maximal inhibition (IC50) was 4.9 microM for Ito and 8.6 microM for Isus. Propafenone blocked Ito and Isus in a voltage- and use-independent fashion and accelerated the inactivation time constant of Ito [from 28.3 to 6.7 ms at 10 microM propafenone]. 3. The steady-state inactivation curve for Ito was unaffected by propafenone. Propafenone did not affect the initial current at depolarizing potentials, but it did produce a block that increased as a function of time after depolarization (time constant of 3.4 ms). This suggests that propafenone preferentially blocked Ito in the open state. 4. Propafenone had no significant effect on the rate at which Ito recovered from inactivation at -80 mV suggesting that propafenone dissociates rapidly from the channel. 5. The steady-state activation curve for Isus was not affected by propafenone. Propafenone slowed the time course of the onset of the Isus tail current. This suggests that propafenone blocked Isus in the open state. 6. The present results suggest that, unlike flecainide, propafenone blocks both Ito and Isus in human atrial myocytes in the open state at clinically relevant concentrations.
Collapse
Affiliation(s)
- A Seki
- The Heart Institute of Japan, Tokyo Women's Medical University
| | | | | |
Collapse
|