Cyclic Nucleotide Phosphodiesterase 3A1 Protects the Heart Against Ischemia-Reperfusion Injury.

Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, NY, USA.
Journal of Molecular and Cellular Cardiology (Impact Factor: 4.66). 08/2013; 64. DOI: 10.1016/j.yjmcc.2013.08.003
Source: PubMed


Phosphodiesterase 3A (PDE3A) is a major regulator of cAMP in cardiomyocytes. PDE3 inhibitors are used for acute treatment of congestive heart failure, but are associated with increased incidence of arrhythmias and sudden death with long-term use. We previously reported that chronic PDE3A downregulation or inhibition induced myocyte apoptosis in vitro. However, the cardiac protective effect of PDE3A has not been demonstrated in vivo in disease models. In this study, we examined the role of PDE3A in regulating myocardial function and survival in vivo using genetically engineered transgenic mice with myocardial overexpression of the PDE3A1 isozyme (TG). TG mice have reduced cardiac function characterized by reduced heart rate and ejection fraction (52.5±7.8% vs. 83.9±4.7%) as well as compensatory expansion of left ventricular diameter (4.19±0.19mm vs. 3.10±0.18mm). However, there was no maladaptive increase of fibrosis and apoptosis in TG hearts compared to wild type (WT) hearts, and the survival rates also remained the same. The diminution of cardiac contractile function is very likely attributed to a decrease in beta-adrenergic receptor (β-AR) response in TG mice. Importantly, the myocardial infarct size (4.0±1.8% vs. 24.6±3.8%) and apoptotic cell number (1.3±1.0% vs. 5.6±1.5%) induced by ischemia/reperfusion (I/R) injury were significantly attenuated in TG mice. This was associated with decreased expression of inducible cAMP early repressor (ICER) and increased expression of anti-apoptotic protein BCL-2. To further verify the anti-apoptotic effects of PDE3A1, we performed in vitro apoptosis study in isolated adult TG and WT cardiomyocytes. We found that the apoptotic rates stimulated by hypoxia/reoxygenation or H2O2 were indeed significantly reduced in TG myocytes, and the differences between TG and WT myocytes were completely reversed in the presence of the PDE3 inhibitor milrinone. These together indicate that PDE3A1 negatively regulates β-AR signaling and protects against I/R injury by inhibiting cardiomyocyte apoptosis.

Download full-text


Available from: Clint Miller
  • [Show abstract] [Hide abstract]
    ABSTRACT: Accumulating evidence suggests that there are direct interactions between β-adrenergic and angiotensin II signaling pathways, and β-blockers protect the heart against angiotensin II-induced cardiac remodeling. Phosphodiesterase 3A (PDE3A) regulates β-adrenergic receptor/protein kinase A signaling by metabolizing cAMP. Therefore, we hypothesized that overexpressed PDE3A has cardioprotective effects against angiotensin II-induced cardiac remodeling by regulating angiotensin II signaling. In the present study, we used transgenic mice with cardiac-specific overexpressed PDE3A1. We showed that continuous administration of angiotensin II caused cardiac hypertrophy in the wild-type mouse heart, but not in the transgenic mouse heart. Angiotensin II induced cardiac fibrosis in both wild-type and transgenic mice, but the extent of fibrosis was less in transgenic mice compared to wild-type mice. Moreover, basal expression levels of transforming growth factor-β were lower in transgenic mouse hearts, and it remained at lower levels after angiotensin II stimulation. These findings suggest that PDE3A protects the heart from angiotensin II-induced cardiac remodeling through its modulation of the functional connection between angiotensin II and transforming growth factor-β.
    No preview · Article · Mar 2014 · International Heart Journal
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cyclic nucleotide phosphodiesterases (PDEs) catalyse the hydrolysis of cyclic AMP and cyclic GMP, thereby regulating the intracellular concentrations of these cyclic nucleotides, their signalling pathways and, consequently, myriad biological responses in health and disease. Currently, a small number of PDE inhibitors are used clinically for treating the pathophysiological dysregulation of cyclic nucleotide signalling in several disorders, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication and chronic obstructive pulmonary disease. However, pharmaceutical interest in PDEs has been reignited by the increasing understanding of the roles of individual PDEs in regulating the subcellular compartmentalization of specific cyclic nucleotide signalling pathways, by the structure-based design of novel specific inhibitors and by the development of more sophisticated strategies to target individual PDE variants.
    Full-text · Article · Apr 2014 · Nature Reviews Drug Discovery
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cyclic AMP regulates a multitude of cellular responses and orchestrates a network of intracellular events. In the heart, cAMP is the main second messenger of the β-adrenergic receptor (β-AR) pathway producing positive chronotropic, inotropic, and lusitropic effects during sympathetic stimulation. Whereas short-term stimulation of β-AR/cAMP is beneficial for the heart, chronic activation of this pathway triggers pathological cardiac remodeling, which may ultimately lead to heart failure (HF). Cyclic AMP is controlled by two families of enzymes with opposite actions: adenylyl cyclases, which control cAMP production and phosphodiesterases, which control its degradation. The large number of families and isoforms of these enzymes, their different localization within the cell, and their organization in macromolecular complexes leads to a high level of compartmentation, both in space and time, of cAMP signaling in cardiac myocytes. Here, we review the expression level, molecular characteristics, functional properties, and roles of the different adenylyl cyclase and phosphodiesterase families expressed in heart muscle and the changes that occur in cardiac hypertrophy and failure.
    No preview · Article · Apr 2014 · Pflügers Archiv - European Journal of Physiology
Show more