Abstract 26: Myocardial Phosphodiesterase-2A Is Upregulated in Human and Experimental Heart Failure and Blunts Cardiac β-Adrenergic Inotropic Responsiveness

Augmented cGMP- and diminished cAMP-signaling within cardiomyocytes is characteristic for failing hearts. Cyclic nucleotide phosphodiesterases (PDEs) comprise a family of cyclic-nucleotide hydrolyzing enzymes, controlling cAMP and cGMP levels. Among them the PDE-2A isoform has the unique property to be stimulated by cGMP but primarily hydrolyzing cAMP. This appears to mediate a negative cross-talk between both signaling pathways. However, a potential role for PDE-2A in the failing heart has not been addressed yet. Here we show that PDE-2A protein levels were ∼2-fold higher in failing human hearts as well as in a large animal heart failure model from dog hearts subjected to rapid-pacing (n≥6, p<0.05). Intriguingly, PDE-2A protein levels were normal in hypertrophied hearts from patients with preserved cardiac function who underwent aortic valve replacement. Chronic beta-adrenergic stimulation by catecholamine infusions enhanced cAMP hydrolyzing activity of PDE-2A by four-fold (n≥6, p<0.05) in rat hearts in vivo and in isolated cardiomyocytes (measured by radioimmunoassay and FRET-based sensors, respectively) and correlated with blunted beta-adrenergic responsiveness. Consistent with this observation, overexpressed PDE-2A, which localized to the sarcomeric Z-line, blunted the rise in cAMP by 70% (n≥6, p<0.05) and abolished the positive inotropic effect after acute beta-adrenergic stimulation by 70% (n≥6, p<0.05) in isolated cardiomyocytes. Notably, those cardiomyocytes also showed marked protection from norepinephrine-induced hypertrophic responses, e. g. 40% less increase in cell surface area (n≥10, p<0.05). In summary, PDE-2A is markedly upregulated in human and experimental failing hearts. This may constitute an important defense mechanism during cardiac stress, by antagonizing the cAMP-mediated toxic effects. Thus, activating myocardial PDE-2A may represent a new intracellular anti-adrenergic therapeutic strategy in heart failure.

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In vivo and in vitro cardiac responses to beta-adrenergic stimulation in volume-overload heart failure

Journal of Molecular and Cellular Cardiology ◽

10.1016/j.yjmcc.2012.11.013 ◽

2013 ◽

Vol 57 ◽

pp. 47-58 ◽

Cited By ~ 17

Author(s):

Anuradha Guggilam ◽

Kirk R. Hutchinson ◽

T. Aaron West ◽

Amy P. Kelly ◽

Maarten L. Galantowicz ◽

...

Keyword(s):

Heart Failure ◽

Volume Overload ◽

Adrenergic Stimulation ◽

Beta Adrenergic ◽

Cardiac Responses

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Catecholamine Surges Cause Cardiomyocyte Necroptosis via a RIPK1–RIPK3-Dependent Pathway in Mice

Frontiers in Cardiovascular Medicine ◽

10.3389/fcvm.2021.740839 ◽

2021 ◽

Vol 8 ◽

Author(s):

Penglong Wu ◽

Mingqi Cai ◽

Jinbao Liu ◽

Xuejun Wang

Keyword(s):

Heart Failure ◽

Cardiac Injury ◽

Underlying Mechanism ◽

Selective Inhibitor ◽

Blue Dye ◽

Wild Type ◽

Adrenergic Stimulation ◽

Protein Levels ◽

Regulated Necrosis ◽

Dependent Pathway

Background: Catecholamine surges and resultant excessive β-adrenergic stimulation occur in a broad spectrum of diseases. Excessive β-adrenergic stimulation causes cardiomyocyte necrosis, but the underlying mechanism remains obscure. Necroptosis, a major form of regulated necrosis mediated by RIPK3-centered pathways, is implicated in heart failure; however, it remains unknown whether excessive β-adrenergic stimulation-induced cardiac injury involves necroptosis. Hence, we conducted the present study to address these critical gaps.Methods and Results: Two consecutive daily injections of isoproterenol (ISO; 85 mg/kg, s.c.) or saline were administered to adult mixed-sex mice. At 24 h after the second ISO injection, cardiac area with Evans blue dye (EBD) uptake and myocardial protein levels of CD45, RIPK1, Ser166-phosphorylated RIPK1, RIPK3, and Ser345-phosphorylated MLKL (p-MLKL) were significantly greater, while Ser321-phosphorylated RIPK1 was significantly lower, in the ISO-treated than in saline-treated wild-type (WT) mice. The ISO-induced increase of EBD uptake was markedly less in RIPK3−/− mice compared with WT mice (p = 0.016). Pretreatment with the RIPK1-selective inhibitor necrostatin-1 diminished ISO-induced increases in RIPK3 and p-MLKL in WT mice and significantly attenuated ISO-induced increases of EBD uptake in WT but not RIPK3−/− mice.Conclusions: A large proportion of cardiomyocyte necrosis induced by excessive β-adrenergic stimulation belongs to necroptosis and is mediated by a RIPK1–RIPK3-dependent pathway, identifying RIPK1 and RIPK3 as potential therapeutic targets for catecholamine surges.

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Abstract 543: Clinical Development of Cardiac Reprogramming Gene Therapy

Circulation Research ◽

10.1161/res.127.suppl_1.543 ◽

2020 ◽

Vol 127 (Suppl_1) ◽

Author(s):

Huanyu Zhou ◽

Laura M Lombardi ◽

Christopher A Reid ◽

Jin Yang ◽

Chetan Srinath ◽

...

Keyword(s):

Heart Failure ◽

Gene Therapy ◽

Clinical Application ◽

Cardiac Fibroblasts ◽

Target Cells ◽

Large Animal ◽

Safety And Efficacy ◽

Treat Heart Failure ◽

Ability To Regenerate

Heart failure affects an estimated 38 million people worldwide and is typically caused by cardiomyocyte (CM) loss or dysfunction. Although CMs have limited ability to regenerate, a large pool of non-myocytes, including cardiac fibroblasts (CFs), exist in the postnatal heart. In vivo reprogramming of non-myocytes into functional CMs is emerging as a potential new approach to treat heart failure and substantial proof-of-concept has been achieved in this new field. However, challenges remain in terms of clinical application. First, reported human reprogramming cocktails often consist of five to seven factors that require multiple AAV vectors for delivery. Thus, a less complex cocktail that is able to fit into one AAV vector is needed for this technology to impact human health. Second, the lack of specificity in AAV tropism further complicates the safety and regulatory landscape. A means to limit the expression of reprogramming factors to target cells is critical for maximizing long-term safety. Lastly, although promising studies in small animals have already been reported, safety and efficacy results in large animal MI models are critical to justify cardiac reprogramming in human clinical trials. We have developed a novel human cardiac reprogramming cocktail that consists of only two transcription factors and one miRNA. This new cocktail has been engineered into a single AAV cassette to efficiently reprogram human CFs into cardiomyocytes. We also substantially improved transduction of hCFs through AAV capsid engineering and eliminated CMs expression through a microRNA de-targeting method. Moreover, our novel cardiac reprogramming gene therapy improved cardiac function in both rat and swine MI models upon delivery at various time-points after MI without inducing arrhythmias. Given these promising safety and efficacy results in larger animals, we endeavor to translate direct cardiac reprogramming for clinical application.

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Abstract 528: Restricted Proteasome Heterogeneity Promotes Premature Heart Failure and Deterioration of Associated Protein Levels Upon Continuous β-Adrenergic Stimulation

Circulation Research ◽

10.1161/res.125.suppl_1.528 ◽

2019 ◽

Vol 125 (Suppl_1) ◽

Author(s):

Felix A Trogisch ◽

Franziska Koser ◽

Andreas Jungmann ◽

Oliver J Müller ◽

Markus Hecker ◽

...

Keyword(s):

Heart Failure ◽

Adrenergic Stimulation ◽

Protein Levels

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Inotropic sensitivity to beta-adrenergic stimulation in early sepsis

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1988.255.4.h699 ◽

1988 ◽

Vol 255 (4) ◽

pp. H699-H703 ◽

Cited By ~ 4

Author(s):

L. W. Smith ◽

K. H. McDonough

Keyword(s):

Contractile Function ◽

Plasma Catecholamines ◽

Left Ventricular ◽

Adrenergic Stimulation ◽

Maximal Increase ◽

Beta Adrenergic ◽

Arterial Blood ◽

Myocardial Contractile ◽

Early Sepsis

In early sepsis, maintenance of in vivo cardiovascular performance is at least partly dependent on sympathetic support to hearts with intrinsic contractile defects. Yet prolonged sympathetic stimulation, as occurs in sepsis, would be expected to alter the heart's ability to respond to this stimulation. We have investigated myocardial inotropic sensitivity to beta-adrenergic stimulation in a model of sepsis in which animals, at the time studied, exhibited bacteremia, normal arterial blood pressure and cardiac output, elevated heart rate, and elevated plasma catecholamines. Intrinsic myocardial contractile function, as assessed by the maximal rate of left ventricular pressure development (LV dP/dtmax) in an isovolumically contracting heart preparation, was significantly depressed in septic animals. To determine whether hearts from septic animals could respond normally to beta-adrenergic stimulation, we studied inotropic response to a bolus of isoproterenol in these isolated hearts. With maximal isoproterenol stimulation, hearts from septic animals were able to attain the same dP/dtmax as were hearts from control animals. With lower levels of isoproterenol, there was also no difference in inotropic indexes between the two groups when response was expressed as a percent of the maximal increase in dP/dtmax achieved with isoproterenol. These results suggest that in early sepsis, despite intrinsic myocardial contractile dysfunction, the ability of the heart to modulate its inotropic state in response in beta-adrenergic stimulation is intact.

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Decreased cyclic-AMP generation in lymphocytes by $beta;-adrenergic stimulation in congestive heart failure (CHF)

Journal of Molecular and Cellular Cardiology ◽

10.1016/0022-2828(79)90039-7 ◽

1979 ◽

Vol 11 ◽

pp. 36

Author(s):

K MINAKUCHI

Keyword(s):

Heart Failure ◽

Congestive Heart Failure ◽

Cyclic Amp ◽

Adrenergic Stimulation ◽

Beta Adrenergic

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Energy metabolism in trout red cells: consequences of adrenergic stimulation in vivo and in vitro

Journal of Experimental Biology ◽

10.1242/jeb.143.1.133 ◽

1989 ◽

Vol 143 (1) ◽

pp. 133-147 ◽

Cited By ~ 3

Author(s):

R. A. Ferguson ◽

B. L. Tufts ◽

R. G. Boutilier

Keyword(s):

Ph Regulation ◽

Red Cells ◽

Red Cell ◽

Adrenergic Stimulation ◽

Beta Adrenergic ◽

Extracellular Acidosis ◽

Metabolic Functions ◽

The Face

beta-Adrenergic stimulation of salmonid red cells results in a rapid decrease (within 5 min) in the nucleotide triphosphate:haemoglobin ratio (NTP:Hb), which is thereafter maintained at a constant level, presumably through increased ATP turnover via matched aerobic metabolism and energy-consuming processes. Addition of the beta-adrenergic agonist isoproterenol to rainbow trout red cells in vitro leads to a rise in intracellular pH (pHi), a corresponding decrease in extracellular pH (pHe) and an increase in red cell oxygen consumption (MO2). Moreover, the extent to which red cell pHi is maintained constant in the face of an acute extracellular acidosis in vitro or in vivo is proportional to the adrenergically stimulated increase in red cell MO2. In the absence of oxygen, these red cells remain capable of pH regulation, but cannot maintain NTP:Hb constant. As a result, membrane and metabolic functions become uncoupled in the stimulated deoxygenated cells.

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Inhibition of nitric oxide synthase augments myocardial contractile responses to beta-adrenergic stimulation

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1996.271.6.h2646 ◽

1996 ◽

Vol 271 (6) ◽

pp. H2646-H2652 ◽

Cited By ~ 12

Author(s):

J. F. Keaney ◽

J. M. Hare ◽

J. L. Balligand ◽

J. Loscalzo ◽

T. W. Smith ◽

...

Keyword(s):

Nitric Oxide ◽

Myocardial Contractility ◽

Adrenergic Stimulation ◽

Maximum Increase ◽

Beta Adrenergic ◽

Before And After ◽

Nos Inhibitor ◽

Oxide Synthase

Recent in vitro evidence suggests a role for nitric oxide (NO) in the modulation of myocardial contractility. The specific role of NO in the control of cardiac function in vivo, however, remains unclear. We investigated the effect of NO synthase (NOS) inhibition on myocardial contractility in response to beta-adrenergic stimulation in autonomically blocked dogs. Intracoronary infusions of dobutamine (1-50 micrograms/min) and isoproterenol (0.1 and 0.5 microgram/min) were performed before and after the intracoronary administration of the specific NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME). Intracoronary dobutamine resulted in a dose-dependent increase in peak first derivative of pressure (dP/dtmax) to a maximum of 195 +/- 10% (P < 0.001). After inhibition of NOS with intracoronary L-NAME at rates of 0.1 and 1 mg/min, the response to dobutamine was significantly enhanced with dP/dtmax, increasing 276 +/- 17 and 317 +/- 26%, respectively (P < 0.001). Intracoronary isoproterenol resulted in a maximum increase in dP/dtmax of 116 +/- 15% (P < 0.001) that further increased to 154 +/- 17 and 157 +/- 18% after NOS inhibition with 0.1 and 1 mg/min L-NAME, respectively (both P < 0.002). L-NAME had no effect on baseline dP/dtmax but did produce a reduction in myocardial guanosine 3',5'-cyclic monophosphate content. These results suggest a role for NO in the control of myocardial contractility in response to beta-adrenergic stimulation in vivo.

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