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Bonsu KO, Owusu IK, Buabeng KO, Reidpath DD, Kadirvelu A. Review of novel therapeutic targets for improving heart failure treatment based on experimental and clinical studies. Ther Clin Risk Manag 2016; 12:887-906. [PMID: 27350750 PMCID: PMC4902145 DOI: 10.2147/tcrm.s106065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Heart failure (HF) is a major public health priority due to its epidemiological transition and the world's aging population. HF is typified by continuous loss of contractile function with reduced, normal, or preserved ejection fraction, elevated vascular resistance, fluid and autonomic imbalance, and ventricular dilatation. Despite considerable advances in the treatment of HF over the past few decades, mortality remains substantial. Pharmacological treatments including β-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone antagonists have been proven to prolong the survival of patients with HF. However, there are still instances where patients remain symptomatic, despite optimal use of existing therapeutic agents. This understanding that patients with chronic HF progress into advanced stages despite receiving optimal treatment has increased the quest for alternatives, exploring the roles of additional pathways that contribute to the development and progression of HF. Several pharmacological targets associated with pathogenesis of HF have been identified and novel therapies have emerged. In this work, we review recent evidence from proposed mechanisms to the outcomes of experimental and clinical studies of the novel pharmacological agents that have emerged for the treatment of HF.
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Affiliation(s)
- Kwadwo Osei Bonsu
- School of Medicine and Health Sciences, Monash University Sunway Campus, Jalan Lagoon Selatan, Bandar Sunway, Subang Jaya, Selangor, Malaysia
- Accident and Emergency Directorate, Komfo Anokye Teaching Hospital, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Isaac Kofi Owusu
- Department of Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Kwame Ohene Buabeng
- Department of Clinical and Social Pharmacy, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Daniel Diamond Reidpath
- School of Medicine and Health Sciences, Monash University Sunway Campus, Jalan Lagoon Selatan, Bandar Sunway, Subang Jaya, Selangor, Malaysia
| | - Amudha Kadirvelu
- School of Medicine and Health Sciences, Monash University Sunway Campus, Jalan Lagoon Selatan, Bandar Sunway, Subang Jaya, Selangor, Malaysia
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102
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Calstabin 2: An important regulator for learning and memory in mice. Sci Rep 2016; 6:21087. [PMID: 26888649 PMCID: PMC4758079 DOI: 10.1038/srep21087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 01/14/2016] [Indexed: 12/20/2022] Open
Abstract
Calstabin2, also named FK506 binding protein 12.6 (FKBP12.6), is a subunit of ryanodine receptor subtype 2 (RyR2) macromolecular complex, which is an intracellular calcium channel and abundant in the brain. Previous studies identified a role of leaky neuronal RyR2 in posttraumatic stress disorder (PTSD). However, the functional role of Calstabin2 in the cognitive function remains unclear. Herein, we used a mouse model of genetic deletion of Calstabin2 to investigate the function of Calstabin2 in cognitive dysfunction. We found that Calstabin2 knockout (KO) mice showed significantly reduced performance in Morris Water Maze (MWM), long-term memory (LTM) contextual fear testing, and rotarod test when compared to wild type (WT) littermates. Indeed, genetic deletion of Calstabin2 reduced long-term potentiation (LTP) at the hippocampal CA3-CA1 connection, increased membrane excitability, and induced RyR2 leak. Finally, we demonstrated that the increase in cytoplasmic calcium activated Ca(2+) dependent potassium currents and led to neuronal apoptosis in KO hippocampal neurons. Thus, these results suggest that neuronal RyR2 Ca(2+) leak due to Calstabin2 deletion contributes to learning deficiency and memory impairment.
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103
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Fu Y, Shaw SA, Naami R, Vuong CL, Basheer WA, Guo X, Hong T. Isoproterenol Promotes Rapid Ryanodine Receptor Movement to Bridging Integrator 1 (BIN1)-Organized Dyads. Circulation 2016; 133:388-97. [PMID: 26733606 DOI: 10.1161/circulationaha.115.018535] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/21/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND The key pathophysiology of human acquired heart failure is impaired calcium transient, which is initiated at dyads consisting of ryanodine receptors (RyRs) at sarcoplasmic reticulum apposing CaV1.2 channels at t-tubules. Sympathetic tone regulates myocardial calcium transients through β-adrenergic receptor (β-AR)-mediated phosphorylation of dyadic proteins. Phosphorylated RyRs (P-RyR) have increased calcium sensitivity and open probability, amplifying calcium transient at a cost of receptor instability. Given that bridging integrator 1 (BIN1) organizes t-tubule microfolds and facilitates CaV1.2 delivery, we explored whether β-AR-regulated RyRs are also affected by BIN1. METHODS AND RESULTS Isolated adult mouse hearts or cardiomyocytes were perfused for 5 minutes with the β-AR agonist isoproterenol (1 µmol/L) or the blockers CGP+ICI (baseline). Using biochemistry and superresolution fluorescent imaging, we identified that BIN1 clusters P-RyR and CaV1.2. Acute β-AR activation increases coimmunoprecipitation between P-RyR and cardiac spliced BIN1+13+17 (with exons 13 and 17). Isoproterenol redistributes BIN1 to t-tubules, recruiting P-RyRs and improving the calcium transient. In cardiac-specific Bin1 heterozygote mice, isoproterenol fails to concentrate BIN1 to t-tubules, impairing P-RyR recruitment. The resultant accumulation of uncoupled P-RyRs increases the incidence of spontaneous calcium release. In human hearts with end-stage ischemic cardiomyopathy, we find that BIN1 is also 50% reduced, with diminished P-RyR association with BIN1. CONCLUSIONS On β-AR activation, reorganization of BIN1-induced microdomains recruits P-RyR into dyads, increasing the calcium transient while preserving electric stability. When BIN1 is reduced as in human acquired heart failure, acute stress impairs microdomain formation, limiting contractility and promoting arrhythmias.
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Affiliation(s)
- Ying Fu
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Seiji A Shaw
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Robert Naami
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Caresse L Vuong
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Wassim A Basheer
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Xiuqing Guo
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - TingTing Hong
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.).
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Abstract
Heightened cardiac adrenergic nervous system (ANS) activity and progression of left ventricular (LV) remodeling are temporally related in patients with systolic heart failure. Whether cardiac ANS activation directly contributes to or merely accompanies LV remodeling remains an unresolved issue. Human and experimental data that directly link cardiac ANS activation to LV remodeling and worsening heart failure are first reviewed, including cardiac norepinephrine spillover. Alterations of beta adrenergic receptor signaling pathways are then addressed with emphasis on the mechanisms that may mediate the beneficial effect of beta adrenergic receptor blockade on LV remodeling. Lastly, alternative approaches to beta adrenergic receptor blockade for lessening cardiac ANS activation and reversing cardiac ANS-induced LV remodeling are discussed. A large body of work now links LV remodeling to cardiac ANS activation. However, the precise mechanisms that link cardiac ANS activation to LV remodeling are still to be fully understood. Fully understanding of these mechanisms may uncover new therapeutic approaches.
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105
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Bowman LJ, Brennan DC, Delos-Santos R, LaRue SJ, Anwar S, Klein CL. Tacrolimus-Induced Cardiomyopathy in an Adult Renal Transplant Recipient. Pharmacotherapy 2015; 35:1109-16. [PMID: 26616582 DOI: 10.1002/phar.1666] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Tacrolimus-induced cardiomyopathy (TICM) is a rare but serious adverse effect of tacrolimus, which has been described primarily in pediatric non-renal transplant recipients. We describe a case of TICM in an adult renal transplant recipient that resulted in allograft dysfunction and multiple hospital admissions for heart failure exacerbation. Prompt and complete reversal of TICM occurred after tacrolimus discontinuation. Although tacrolimus-induced cardiomyopathy is reversible, availability of alternative immunosuppressants is limited, particularly in the setting of renal dysfunction. Available studies and patient-specific factors must be considered when determining an alternative maintenance immunosuppression regimen. We chose to use belatacept as alternative immunosuppression in this patient with TICM. Over the next 3 years, the patient remained free of hospital admissions and acute rejection, and demonstrated superior renal allograft function than was observed before her first heart failure admission. We believe that belatacept is an acceptable alternative to tacrolimus therapy for resolution of TICM.
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Affiliation(s)
- Lyndsey J Bowman
- Department of Pharmacy, Barnes-Jewish Hospital, St. Louis, Missouri
| | - Daniel C Brennan
- Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri
| | - Rowena Delos-Santos
- Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri
| | - Shane J LaRue
- Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri
| | - Siddiq Anwar
- Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri
| | - Christina L Klein
- Department of Medicine, Piedmont Transplant Institute, Atlanta, Georgia
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106
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Crosstalk between RyR2 oxidation and phosphorylation contributes to cardiac dysfunction in mice with Duchenne muscular dystrophy. J Mol Cell Cardiol 2015; 89:177-84. [PMID: 26555638 DOI: 10.1016/j.yjmcc.2015.11.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/28/2015] [Accepted: 11/05/2015] [Indexed: 12/24/2022]
Abstract
BACKGROUND Patients with Duchenne muscular dystrophy (DMD) are at risk of developing cardiomyopathy and cardiac arrhythmias. Studies in a mouse model of DMD revealed that enhanced sarcoplasmic reticulum (SR) Ca(2+) leak contributes to the pathogenesis of cardiac dysfunction. In view of recent data suggesting the involvement of altered phosphorylation and oxidation of the cardiac ryanodine receptor (RyR2)/Ca(2+) release channel, we hypothesized that inhibition of RyR2 phosphorylation in a mouse model of DMD can prevent SR Ca(2+) leak by reducing RyR2 oxidation. METHODS AND RESULTS Confocal Ca(2+) imaging and single RyR2 channel recordings revealed that both inhibition of S2808 or S2814 phosphorylation, and inhibition of oxidation could normalize RyR2 activity in mdx mice. Moreover, Western blotting revealed that genetic inhibition of RyR2 phosphorylation at S2808 or S2814 reduced RyR2 oxidation. Production of reactive oxygen species (ROS) in myocytes from mdx mice was reduced by both inhibition of RyR2 phosphorylation or the ROS scavenger 2-mercaptopropionyl glycine (MPG). Finally, it was shown that ROS production in mdx mice is proportional to the activity of RyR2-mediated SR Ca(2+) leak, and likely generated by Nox2. CONCLUSIONS Increased ROS production in the hearts of mdx mice drives the progression of cardiac dysfunction. Inhibition of RyR2 phosphorylation can suppress SR Ca(2+) leak in mdx mouse hearts in part by reducing RyR2 oxidation.
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107
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Roe AT, Frisk M, Louch WE. Targeting cardiomyocyte Ca2+ homeostasis in heart failure. Curr Pharm Des 2015; 21:431-48. [PMID: 25483944 PMCID: PMC4475738 DOI: 10.2174/138161282104141204124129] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 08/06/2014] [Indexed: 12/19/2022]
Abstract
Improved treatments for heart failure patients will require the development of novel therapeutic strategies that target basal disease
mechanisms. Disrupted cardiomyocyte Ca2+ homeostasis is recognized as a major contributor to the heart failure phenotype, as it
plays a key role in systolic and diastolic dysfunction, arrhythmogenesis, and hypertrophy and apoptosis signaling. In this review, we outline
existing knowledge of the involvement of Ca2+ homeostasis in these deficits, and identify four promising targets for therapeutic intervention:
the sarcoplasmic reticulum Ca2+ ATPase, the Na+-Ca2+ exchanger, the ryanodine receptor, and t-tubule structure. We discuss
experimental data indicating the applicability of these targets that has led to recent and ongoing clinical trials, and suggest future therapeutic
approaches.
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Affiliation(s)
| | | | - William E Louch
- Institute for Experimental Medical Research, Kirkeveien 166, 4.etg. Bygg 7, Oslo University Hospital Ullevål, 0407 Oslo, Norway.
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108
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Johnston AS, Lehnart SE, Burgoyne JR. Ca(2+) signaling in the myocardium by (redox) regulation of PKA/CaMKII. Front Pharmacol 2015; 6:166. [PMID: 26321952 PMCID: PMC4530260 DOI: 10.3389/fphar.2015.00166] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/24/2015] [Indexed: 12/21/2022] Open
Abstract
Homeostatic cardiac function is maintained by a complex network of interdependent signaling pathways which become compromised during disease progression. Excitation-contraction-coupling, the translation of an electrical signal to a contractile response is critically dependent on a tightly controlled sequence of events culminating in a rise in intracellular Ca(2+) and subsequent contraction of the myocardium. Dysregulation of this Ca(2+) handling system as well as increases in the production of reactive oxygen species (ROS) are two major contributing factors to myocardial disease progression. ROS, generated by cellular oxidases and by-products of cellular metabolism, are highly reactive oxygen derivatives that function as key secondary messengers within the heart and contribute to normal homeostatic function. However, excessive production of ROS, as in disease, can directly interact with kinases critical for Ca(2+) regulation. This post-translational oxidative modification therefore links changes in the redox status of the myocardium to phospho-regulated pathways essential for its function. This review aims to describe the oxidative regulation of the Ca(2+)/calmodulin-dependent kinase II (CaMKII) and cAMP-dependent protein kinase A (PKA), and the subsequent impact this has on Ca(2+) handling within the myocardium. Elucidating the impact of alterations in intracellular ROS production on Ca(2+) dynamics through oxidative modification of key ROS sensing kinases, may provide novel therapeutic targets for preventing myocardial disease progression.
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Affiliation(s)
- Alex S Johnston
- Heart Research Center Goettingen, Clinic of Cardiology and Pulmonology, University Medical Center Goettingen Goettingen, Germany
| | - Stephan E Lehnart
- Heart Research Center Goettingen, Clinic of Cardiology and Pulmonology, University Medical Center Goettingen Goettingen, Germany ; German Center for Cardiovascular Research (DZHK) site Göttingen Berlin, Germany
| | - Joseph R Burgoyne
- Cardiovascular Division, The British Heart Foundation Centre of Excellence, The Rayne Institute, King's College London, St. Thomas' Hospital London, UK
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109
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Suita K, Fujita T, Hasegawa N, Cai W, Jin H, Hidaka Y, Prajapati R, Umemura M, Yokoyama U, Sato M, Okumura S, Ishikawa Y. Norepinephrine-Induced Adrenergic Activation Strikingly Increased the Atrial Fibrillation Duration through β1- and α1-Adrenergic Receptor-Mediated Signaling in Mice. PLoS One 2015. [PMID: 26203906 PMCID: PMC4512675 DOI: 10.1371/journal.pone.0133664] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common arrhythmias among old people. It causes serious long-term health problems affecting the quality of life. It has been suggested that the autonomic nervous system is involved in the onset and maintenance of AF in human. However, investigation of its pathogenesis and potential treatment has been hampered by the lack of suitable AF models in experimental animals. OBJECTIVES Our aim was to establish a long-lasting AF model in mice. We also investigated the role of adrenergic receptor (AR) subtypes, which may be involved in the onset and duration of AF. METHODS AND RESULTS Trans-esophageal atrial burst pacing in mice could induce AF, as previously shown, but with only a short duration (29.0 ± 8.1 sec). We found that adrenergic activation by intraperitoneal norepinephrine (NE) injection strikingly increased the AF duration. It increased the duration to more than 10 minutes, i.e., by more than 20-fold (656.2 ± 104.8 sec; P<0.001). In this model, a prior injection of a specific β1-AR blocker metoprolol and an α1-AR blocker prazosin both significantly attenuated NE-induced elongation of AF. To further explore the mechanisms underlying these receptors' effects on AF, we assessed the SR Ca(2+) leak, a major trigger of AF, and consequent spontaneous SR Ca(2+) release (SCR) in atrial myocytes. Consistent with the results of our in-vivo experiments, both metoprolol and prazosin significantly inhibited the NE-induced SR Ca(2+) leak and SCR. These findings suggest that both β1-AR and α1-AR may play important roles in the development of AF. CONCLUSIONS We have established a long-lasting AF model in mice induced by adrenergic activation, which will be valuable in future AF study using experimental animals, such as transgenic mice. We also revealed the important role of β1- and α1-AR-mediated signaling in the development of AF through in-vivo and in-vitro experiments.
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MESH Headings
- Adrenergic alpha-Antagonists/pharmacology
- Adrenergic beta-Antagonists/pharmacology
- Animals
- Atrial Fibrillation/chemically induced
- Atrial Fibrillation/physiopathology
- Calcium Signaling/drug effects
- Cells, Cultured
- Disease Models, Animal
- Heart Conduction System/drug effects
- Heart Conduction System/physiopathology
- Injections, Intraperitoneal
- Male
- Metoprolol/pharmacology
- Mice
- Mice, Inbred C57BL
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/physiology
- Norepinephrine/administration & dosage
- Norepinephrine/toxicity
- Prazosin/pharmacology
- Receptors, Adrenergic, alpha-1/drug effects
- Receptors, Adrenergic, alpha-1/physiology
- Receptors, Adrenergic, beta-1/drug effects
- Receptors, Adrenergic, beta-1/physiology
- Sarcoplasmic Reticulum/drug effects
- Sympathetic Nervous System/drug effects
- Sympathetic Nervous System/physiopathology
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Affiliation(s)
- Kenji Suita
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Takayuki Fujita
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- * E-mail: (TF); (YI)
| | - Nozomi Hasegawa
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Wenqian Cai
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Huiling Jin
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yuko Hidaka
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Rajesh Prajapati
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Masanari Umemura
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Utako Yokoyama
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Motohiko Sato
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Physiology, Aichi Medical University School of Medicine, Aichi, Japan
| | - Satoshi Okumura
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Yoshihiro Ishikawa
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- * E-mail: (TF); (YI)
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110
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Mitochondrial oxidative stress promotes atrial fibrillation. Sci Rep 2015; 5:11427. [PMID: 26169582 PMCID: PMC4501003 DOI: 10.1038/srep11427] [Citation(s) in RCA: 196] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/26/2015] [Indexed: 12/11/2022] Open
Abstract
Oxidative stress has been suggested to play a role in the pathogenesis of atrial fibrillation (AF). Indeed, the prevalence of AF increases with age as does oxidative stress. However, the mechanisms linking redox state to AF are not well understood. In this study we identify a link between oxidative stress and aberrant intracellular Ca2+ release via the type 2 ryanodine receptor (RyR2) that promotes AF. We show that RyR2 are oxidized in the atria of patients with chronic AF compared with individuals in sinus rhythm. To dissect the molecular mechanism linking RyR2 oxidation to AF we used two murine models harboring RyR2 mutations that cause intracellular Ca2+ leak. Mice with intracellular Ca2+ leak exhibited increased atrial RyR2 oxidation, mitochondrial dysfunction, reactive oxygen species (ROS) production and AF susceptibility. Both genetic inhibition of mitochondrial ROS production and pharmacological treatment of RyR2 leakage prevented AF. Collectively, our results indicate that alterations of RyR2 and mitochondrial ROS generation form a vicious cycle in the development of AF. Targeting this previously unrecognized mechanism could be useful in developing effective interventions to prevent and treat AF.
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111
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Oxidation of ryanodine receptor (RyR) and calmodulin enhance Ca release and pathologically alter, RyR structure and calmodulin affinity. J Mol Cell Cardiol 2015; 85:240-8. [PMID: 26092277 DOI: 10.1016/j.yjmcc.2015.06.009] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 05/12/2015] [Accepted: 06/12/2015] [Indexed: 11/21/2022]
Abstract
Oxidative stress may contribute to cardiac ryanodine receptor (RyR2) dysfunction in heart failure (HF) and arrhythmias. Altered RyR2 domain-domain interaction (domain unzipping) and calmodulin (CaM) binding affinity are allosterically coupled indices of RyR2 conformation. In HF RyR2 exhibits reduced CaM binding, increased domain unzipping and greater SR Ca leak, and dantrolene can reverse these changes. However, effects of oxidative stress on RyR2 conformation and leak in myocytes are poorly understood. We used fluorescent CaM, FKBP12.6, and domain-peptide biosensor (F-DPc10) to measure, directly in cardiac myocytes, (1) RyR2 activation by hydrogen peroxide (H2O2)-induced oxidation, (2) RyR2 conformation change caused by oxidation, (3) CaM-RyR2 and FK506-binding protein (FKBP12.6)-RyR2 interaction upon oxidation, and (4) whether dantrolene affects 1-3. H2O2 was used to mimic oxidative stress. H2O2 significantly increased the frequency of Ca(2+) sparks and spontaneous Ca(2+) waves, and dantrolene almost completely blocked these effects. H2O2 pretreatment significantly reduced CaM-RyR2 binding, but had no effect on FKBP12.6-RyR2 binding. Dantrolene restored CaM-RyR2 binding but had no effect on intracellular and RyR2 oxidation levels. H2O2 also accelerated F-DPc10-RyR2 association while dantrolene slowed it. Thus, H2O2 causes conformational changes (sensed by CaM and DPc10 binding) associated with Ca leak, and dantrolene reverses these RyR2 effects. In conclusion, in cardiomyocytes, H2O2 treatment markedly reduces the CaM-RyR2 affinity, has no effect on FKBP12.6-RyR2 affinity, and causes domain unzipping. Dantrolene can correct domain unzipping, restore CaM-RyR2 affinity, and quiet pathological RyR2 channel gating. F-DPc10 and CaM are useful biosensors of a pathophysiological RyR2 state.
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112
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van Westering TLE, Betts CA, Wood MJA. Current understanding of molecular pathology and treatment of cardiomyopathy in duchenne muscular dystrophy. Molecules 2015; 20:8823-55. [PMID: 25988613 PMCID: PMC6272314 DOI: 10.3390/molecules20058823] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 12/27/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a genetic muscle disorder caused by mutations in the Dmd gene resulting in the loss of the protein dystrophin. Patients do not only experience skeletal muscle degeneration, but also develop severe cardiomyopathy by their second decade, one of the main causes of death. The absence of dystrophin in the heart renders cardiomyocytes more sensitive to stretch-induced damage. Moreover, it pathologically alters intracellular calcium (Ca2+) concentration, neuronal nitric oxide synthase (nNOS) localization and mitochondrial function and leads to inflammation and necrosis, all contributing to the development of cardiomyopathy. Current therapies only treat symptoms and therefore the need for targeting the genetic defect is immense. Several preclinical therapies are undergoing development, including utrophin up-regulation, stop codon read-through therapy, viral gene therapy, cell-based therapy and exon skipping. Some of these therapies are undergoing clinical trials, but these have predominantly focused on skeletal muscle correction. However, improving skeletal muscle function without addressing cardiac aspects of the disease may aggravate cardiomyopathy and therefore it is essential that preclinical and clinical focus include improving heart function. This review consolidates what is known regarding molecular pathology of the DMD heart, specifically focusing on intracellular Ca2+, nNOS and mitochondrial dysregulation. It briefly discusses the current treatment options and then elaborates on the preclinical therapeutic approaches currently under development to restore dystrophin thereby improving pathology, with a focus on the heart.
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Affiliation(s)
- Tirsa L E van Westering
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3QX, UK
| | - Corinne A Betts
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3QX, UK.
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3QX, UK.
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Secretoneurin is a novel prognostic cardiovascular biomarker associated with cardiomyocyte calcium handling. J Am Coll Cardiol 2015; 65:339-351. [PMID: 25634832 DOI: 10.1016/j.jacc.2014.10.065] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 10/22/2014] [Accepted: 10/28/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND Secretoneurin (SN) levels are increased in patients with heart failure (HF), but whether SN provides prognostic information and influences cardiomyocyte function is unknown. OBJECTIVES This study sought to evaluate the merit of SN as a cardiovascular biomarker and assess effects of SN on cardiomyocyte Ca(2+) handling. METHODS We assessed the association between circulating SN levels and mortality in 2 patient cohorts and the functional properties of SN in experimental models. RESULTS In 143 patients hospitalized for acute HF, SN levels were closely associated with mortality (n = 66) during follow-up (median 776 days; hazard ratio [lnSN]: 4.63; 95% confidence interval: 1.93 to 11.11; p = 0.001 in multivariate analysis). SN reclassified patients to their correct risk strata on top of other predictors of mortality. In 155 patients with ventricular arrhythmia-induced cardiac arrest, SN levels were also associated with short-term mortality (n = 51; hazard ratio [lnSN]: 3.33; 95% confidence interval: 1.83 to 6.05; p < 0.001 in multivariate analysis). Perfusing hearts with SN yielded markedly increased myocardial levels and SN internalized into cardiomyocytes by endocytosis. Intracellularly, SN reduced Ca(2+)/calmodulin (CaM)-dependent protein kinase II δ (CaMKIIδ) activity via direct SN-CaM and SN-CaMKII binding and attenuated CaMKIIδ-dependent phosphorylation of the ryanodine receptor. SN also reduced sarcoplasmic reticulum Ca(2+) leak, augmented sarcoplasmic reticulum Ca(2+) content, increased the magnitude and kinetics of cardiomyocyte Ca(2+) transients and contractions, and attenuated Ca(2+) sparks and waves in HF cardiomyocytes. CONCLUSIONS SN provided incremental prognostic information to established risk indices in acute HF and ventricular arrhythmia-induced cardiac arrest.
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Liu GS, Morales A, Vafiadaki E, Lam CK, Cai WF, Haghighi K, Adly G, Hershberger RE, Kranias EG. A novel human R25C-phospholamban mutation is associated with super-inhibition of calcium cycling and ventricular arrhythmia. Cardiovasc Res 2015; 107:164-74. [PMID: 25852082 DOI: 10.1093/cvr/cvv127] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/20/2015] [Indexed: 12/26/2022] Open
Abstract
AIMS Depressed sarcoplasmic reticulum (SR) Ca(2+) cycling, a universal characteristic of human and experimental heart failure, may be associated with genetic alterations in key Ca(2+)-handling proteins. In this study, we identified a novel PLN mutation (R25C) in dilated cardiomyopathy (DCM) and investigated its functional significance in cardiomyocyte Ca(2+)-handling and contractility. METHODS AND RESULTS Exome sequencing identified a C73T substitution in the coding region of PLN in a family with DCM. The four heterozygous family members had implantable cardiac defibrillators, and three developed prominent ventricular arrhythmias. Overexpression of R25C-PLN in adult rat cardiomyocytes significantly suppressed the Ca(2+) affinity of SR Ca(2+)-ATPase (SERCA2a), resulting in decreased SR Ca(2+) content, Ca(2+) transients, and impaired contractile function, compared with WT-PLN. These inhibitory effects were associated with enhanced interaction of R25C-PLN with SERCA2, which was prevented by PKA phosphorylation. Accordingly, isoproterenol stimulation relieved the depressive effects of R25C-PLN in cardiomyocytes. However, R25C-PLN also elicited increases in the frequency of Ca(2+) sparks and waves as well as stress-induced aftercontractions. This was accompanied by increased Ca(2+)/calmodulin-dependent protein kinase II activity and hyper-phosphorylation of RyR2 at serine 2814. CONCLUSION The findings demonstrate that human R25C-PLN is associated with super-inhibition of SERCA2a and Ca(2+) transport as well as increased SR Ca(2+) leak, promoting arrhythmogenesis under stress conditions. This is the first mechanistic evidence that increased PLN inhibition may impact both SR Ca(2+) uptake and Ca(2+) release activities and suggests that the human R25C-PLN may be a prognostic factor for increased ventricular arrhythmia risk in DCM carriers.
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Affiliation(s)
- Guan-Sheng Liu
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA
| | - Ana Morales
- Division of Human Genetics, Ohio State University College of Medicine, Columbus, OH, USA Dorothy M. Davis Heart and Lung Research Institute, Ohio State University College of Medicine, Columbus, OH 45267-0575, USA
| | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Greece
| | - Chi Keung Lam
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA
| | - Wen-Feng Cai
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kobra Haghighi
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA
| | - George Adly
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA
| | - Ray E Hershberger
- Division of Human Genetics, Ohio State University College of Medicine, Columbus, OH, USA Dorothy M. Davis Heart and Lung Research Institute, Ohio State University College of Medicine, Columbus, OH 45267-0575, USA Division of Cardiovascular Medicine, Department of Internal Medicine, Ohio State University College of Medicine, Columbus, OH, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Greece
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Walweel K, Laver DR. Mechanisms of SR calcium release in healthy and failing human hearts. Biophys Rev 2015; 7:33-41. [PMID: 28509976 PMCID: PMC5425750 DOI: 10.1007/s12551-014-0152-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 11/25/2014] [Indexed: 01/08/2023] Open
Abstract
Normal heart contraction and rhythm relies on the proper flow of calcium ions (Ca2+) into cardiac cells and between their intracellular organelles, and any disruption can lead to arrhythmia and sudden cardiac death. Electrical excitation of the surface membrane activates voltage-dependent L-type Ca2+ channels to open and allow Ca2+ to enter the cytoplasm. The subsequent increase in cytoplasmic Ca2+ concentration activates calcium release channels (RyR2) located at specialised Ca2+ release sites in the sarcoplasmic reticulum (SR), which serves as an intracellular Ca2+ store. Animal models have provided valuable insights into how intracellular Ca2+ transport mechanisms are altered in human heart failure. The aim of this review is to examine how Ca2+ release sites are remodelled in heart failure and how this affects intracellular Ca2+ transport with an emphasis on Ca2+ release mechanisms in the SR. Current knowledge on how heart failure alters the regulation of RyR2 by Ca2+ and Mg2+ and how these mechanisms control the activity of RyR2 in the confines of the Ca2+ release sites is reviewed.
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Affiliation(s)
- K Walweel
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
| | - D R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia.
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Yang X, Wang T, Lin X, Yue X, Wang Q, Wang G, Fu Q, Ai X, Chiang DY, Miyake CY, Wehrens XHT, Chang J. Genetic deletion of Rnd3/RhoE results in mouse heart calcium leakage through upregulation of protein kinase A signaling. Circ Res 2014; 116:e1-e10. [PMID: 25348166 DOI: 10.1161/circresaha.116.304940] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
RATIONALE Rnd3, a small Rho GTPase, is involved in the regulation of cell actin cytoskeleton dynamics, cell migration, and proliferation. The biological function of Rnd3 in the heart remains unexplored. OBJECTIVE To define the functional role of the Rnd3 gene in the animal heart and investigate the associated molecular mechanism. METHODS AND RESULTS By loss-of-function approaches, we discovered that Rnd3 is involved in calcium regulation in cardiomyocytes. Rnd3-null mice died at the embryonic stage with fetal arrhythmias. The deletion of Rnd3 resulted in severe Ca(2+) leakage through destabilized ryanodine receptor type 2 Ca(2+) release channels. We further found that downregulation of Rnd3 attenuated β2-adrenergic receptor lysosomal targeting and ubiquitination, which in turn resulted in the elevation of β2-adrenergic receptor protein levels leading to the hyperactivation of protein kinase A (PKA) signaling. The PKA activation destabilized ryanodine receptor type 2 channels. This irregular spontaneous Ca(2+) release can be curtailed by PKA inhibitor treatment. Increases in the PKA activity along with elevated cAMP levels were detected in Rnd3-null embryos, in neonatal rat cardiomyocytes, and noncardiac cell lines with Rnd3 knockdown, suggesting a general mechanism for Rnd3-mediated PKA signaling activation. β2-Adrenergic receptor blocker treatment reduced arrhythmia and improved cardiac function. CONCLUSIONS Rnd3 is a novel factor involved in intracellular Ca(2+) homeostasis regulation in the heart. Deficiency of the protein induces ryanodine receptor type 2 dysfunction by a mechanism that attenuates Rnd3-mediated β2-adrenergic receptor ubiquitination, which leads to the activation of PKA signaling. Increased PKA signaling in turn promotes ryanodine receptor type 2 hyperphosphorylation, which contributes to arrhythmogenesis and heart failure.
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Affiliation(s)
- Xiangsheng Yang
- Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, TX 77030
| | - Tiannan Wang
- Department of Molecular Physiology & Biophysics, and Medicine (Cardiology), Baylor College of Medicine, Houston, TX 77030
| | - Xi Lin
- Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, TX 77030
| | - Xiaojing Yue
- Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, TX 77030
| | - Qiongling Wang
- Department of Molecular Physiology & Biophysics, and Medicine (Cardiology), Baylor College of Medicine, Houston, TX 77030
| | - Guoliang Wang
- Department of Molecular Physiology & Biophysics, and Medicine (Cardiology), Baylor College of Medicine, Houston, TX 77030
| | - Qin Fu
- Department of Pharmacology, University of California at Davis, CA 95616
| | - Xun Ai
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153
| | - David Y Chiang
- Department of Molecular Physiology & Biophysics, and Medicine (Cardiology), Baylor College of Medicine, Houston, TX 77030
| | - Christina Y Miyake
- Texas Children's Hospital, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
| | - Xander H T Wehrens
- Department of Molecular Physiology & Biophysics, and Medicine (Cardiology), Baylor College of Medicine, Houston, TX 77030
| | - Jiang Chang
- Texas A&M University Health Science Center, Institute of Biosciences and Technology, Houston, TX 77030
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Dobrev D, Wehrens XHT. Role of RyR2 phosphorylation in heart failure and arrhythmias: Controversies around ryanodine receptor phosphorylation in cardiac disease. Circ Res 2014; 114:1311-9; discussion 1319. [PMID: 24723656 DOI: 10.1161/circresaha.114.300568] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cardiac ryanodine receptor type 2 plays a key role in excitation-contraction coupling. The ryanodine receptor type 2 channel protein is modulated by various post-translational modifications, including phosphorylation by protein kinase A and Ca(2+)/calmodulin protein kinase II. Despite extensive research in this area, the functional effects of ryanodine receptor type 2 phosphorylation remain disputed. In particular, the potential involvement of increased ryanodine receptor type 2 phosphorylation in the pathogenesis of heart failure and arrhythmias remains a controversial area, which is discussed in this review article.
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Affiliation(s)
- Dobromir Dobrev
- From the Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany (D.D.); and Cardiovascular Research Institute, Departments of Molecular Physiology and Biophysics, and Medicine-Cardiology, Baylor College of Medicine, Houston, TX (X.H.T.W.)
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Houser SR. Role of RyR2 phosphorylation in heart failure and arrhythmias: protein kinase A-mediated hyperphosphorylation of the ryanodine receptor at serine 2808 does not alter cardiac contractility or cause heart failure and arrhythmias. Circ Res 2014; 114:1320-7; discussion 1327. [PMID: 24723657 DOI: 10.1161/circresaha.114.300569] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This Controversies in Research article discusses the hypothesis that protein kinase A (PKA)-mediated phosphorylation of the Ryanodine Receptor (RyR) at a single serine (RyRS2808) is essential for normal sympathetic regulation of cardiac myocyte contractility and is responsible for the disturbed Ca(2+) regulation that underlies depressed contractility in heart failure. Studies supporting this hypothesis have associated hyperphosphorylation of RyRS2808 and heart failure progression in animals and humans and have shown that a phosphorylation defective RyR mutant mouse (RyRS2808A) does not respond normally to sympathetic agonists and does not exhibit heart failure symptoms after myocardial infarction. Studies to confirm and extend these ideas have failed to support the original data. Experiments from many different laboratories have convincingly shown that PKA-mediated RyRS2808 phosphorylation does not play any significant role in the normal sympathetic regulation of sarcoplasmic reticulum Ca2+ release or cardiac contractility. Hearts and myocytes from RyRS2808A mice have been shown to respond normally to sympathetic agonists, and to increase Ca(2+) influx, Ca(2+) transients, and Ca(2+) efflux. Although the RyR is involved in heart failure-related Ca(2+) disturbances, this results from Ca(2+)-calmodulin kinase II and reactive oxygen species-mediated regulation rather than by RyR2808 phosphorylation. Also, a new study has shown that RyRS2808A mice are not protected from myocardial infarction. Collectively, there is now a clear consensus in the published literature showing that dysregulated RyRs contribute to the altered Ca(2+) regulatory phenotype of the failing heart, but PKA-mediated phosphorylation of RyRS2808 has little or no role in these alterations.
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Affiliation(s)
- Steven R Houser
- From the Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, PA
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Heusch G, Libby P, Gersh B, Yellon D, Böhm M, Lopaschuk G, Opie L. Cardiovascular remodelling in coronary artery disease and heart failure. Lancet 2014; 383:1933-43. [PMID: 24831770 PMCID: PMC4330973 DOI: 10.1016/s0140-6736(14)60107-0] [Citation(s) in RCA: 531] [Impact Index Per Article: 53.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Remodelling is a response of the myocardium and vasculature to a range of potentially noxious haemodynamic, metabolic, and inflammatory stimuli. Remodelling is initially functional, compensatory, and adaptive but, when sustained, progresses to structural changes that become self-perpetuating and pathogenic. Remodelling involves responses not only of the cardiomyocytes, endothelium, and vascular smooth muscle cells, but also of interstitial cells and matrix. In this Review we characterise the remodelling processes in atherosclerosis, vascular and myocardial ischaemia-reperfusion injury, and heart failure, and we draw attention to potential avenues for innovative therapeutic approaches, including conditioning and metabolic strategies.
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Affiliation(s)
- Gerd Heusch
- Institut für Pathophysiologie, Universitätsklinikum Essen, Essen, Germany
| | - Peter Libby
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Bernard Gersh
- Division of Cardiovascular Diseases, Mayo Clinic, and Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Derek Yellon
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - Michael Böhm
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - Gary Lopaschuk
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
| | - Lionel Opie
- Hatter Institute for Cardiovascular Research in Africa, University of Cape Town, Cape Town, South Africa.
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Camors E, Valdivia HH. CaMKII regulation of cardiac ryanodine receptors and inositol triphosphate receptors. Front Pharmacol 2014; 5:101. [PMID: 24847270 PMCID: PMC4021131 DOI: 10.3389/fphar.2014.00101] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 04/17/2014] [Indexed: 01/08/2023] Open
Abstract
Ryanodine receptors (RyRs) and inositol triphosphate receptors (InsP3Rs) are structurally related intracellular calcium release channels that participate in multiple primary or secondary amplified Ca(2+) signals, triggering muscle contraction and oscillatory Ca(2+) waves, or activating transcription factors. In the heart, RyRs play an indisputable role in the process of excitation-contraction coupling as the main pathway for Ca(2+) release from sarcoplasmic reticulum (SR), and a less prominent role in the process of excitation-transcription coupling. Conversely, InsP3Rs are believed to contribute in subtle ways, only, to contraction of the heart, and in more important ways to regulation of transcription factors. Because uncontrolled activity of either RyRs or InsP3Rs may elicit life-threatening arrhythmogenic and/or remodeling Ca(2+) signals, regulation of their activity is of paramount importance for normal cardiac function. Due to their structural similarity, many regulatory factors, accessory proteins, and post-translational processes are equivalent for RyRs and InsP3Rs. Here we discuss regulation of RyRs and InsP3Rs by CaMKII phosphorylation, but touch on other kinases whenever appropriate. CaMKII is emerging as a powerful modulator of RyR and InsP3R activity but interestingly, some of the complexities and controversies surrounding phosphorylation of RyRs also apply to InsP3Rs, and a clear-cut effect of CaMKII on either channel eludes investigators for now. Nevertheless, some effects of CaMKII on global cellular activity, such as SR Ca(2+) leak or force-frequency potentiation, appear clear now, and this constrains the limits of the controversies and permits a more tractable approach to elucidate the effects of phosphorylation at the single channel level.
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Affiliation(s)
- Emmanuel Camors
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor MI, USA
| | - Héctor H Valdivia
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor MI, USA
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Guo X, Yuan S, Liu Z, Fang Q. Oxidation- and CaMKII-mediated sarcoplasmic reticulum Ca(2+) leak triggers atrial fibrillation in aging. J Cardiovasc Electrophysiol 2014; 25:645-52. [PMID: 24576293 DOI: 10.1111/jce.12395] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 02/15/2014] [Accepted: 02/18/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND Advanced age is a well-recognized predisposition to atrial fibrillation (AF). However, the cellular electrophysiological changes that underlie the heightened susceptibility to AF in aged individuals remain poorly understood. Sarcoplasmic reticulum (SR) Ca(2+) leak that results from posttranslational modification of type 2 ryanodine receptor channels (RyR2) has been implicated in arrhythmogenesis. We hypothesize that aging alters atrial myocytes Ca(2+) homeostasis and RyR2 function, which create a substrate for AF initiation. METHODS AND RESULTS We examined the susceptibility to AF in aged (24 months) and young adult (4-5 months) mice using an intraesophageal atrial electrical stimulation protocol. Aged mice showed significant higher AF induction rate (43.3%, n = 30) than young adults (8.8%, n = 34, P < 0.01). In accordance with these in vivo findings, significantly increased diastolic SR Ca(2+) leak and arrhythmogenic Ca(2+) activities with reduced SR Ca(2+) content were observed in aged atrial myocytes. Western blot showed RyR2 oxidation and phosphorylation at Ser2814 (Ca(2+) /calmodulin-dependent protein kinase II [CaMKII] site), but not phosphorylation at Ser2808 (protein kinase A [PKA] and CaMKII site), were increased in aged atrial myocytes. The selective CaMKII inhibitor (KN-93), as well as the antioxidant reagent (DTT) reversed the diastolic Ca(2+) leak and the frequency of spontaneous Ca(2+) transients in aged atrial myocytes, whereas PKA inhibition with H-89 was ineffective. CONCLUSIONS Aging increases both the oxidation and CaMKII-phosphorylation of RyR2, which result in diastolic SR Ca(2+) leak and facilitate AF initiation. These results contribute to the electrophysiological remodeling of aged atria and suggest a therapeutic strategy for AF treatment in aging.
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Affiliation(s)
- Xiaoxiao Guo
- Department of Cardiology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
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Novel drug targets in clinical development for heart failure. Eur J Clin Pharmacol 2014; 70:765-74. [DOI: 10.1007/s00228-014-1671-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 03/19/2014] [Indexed: 01/24/2023]
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Modifications of skeletal muscle ryanodine receptor type 1 and exercise intolerance in heart failure. J Heart Lung Transplant 2014; 32:925-9. [PMID: 23953820 DOI: 10.1016/j.healun.2013.06.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 06/26/2013] [Accepted: 06/28/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND In experimental heart failure animal models, remodeling of skeletal and cardiac muscle ryanodine receptors (RyR), including phosphorylation, S-nitrosylation and oxidation, have been reported to contribute to pathologic Ca2+ release, impaired muscle function and fatigue. However, it is not known whether similar remodeling of RyR1 in skeletal muscle occurs in patients with heart failure, and if this is associated with impairment of physical activity. METHODS We studied 8 sedentary patients with New York Heart Association (NYHA) Class III heart failure and 7 age-matched, healthy, but sedentary controls. All heart failure patients had NYHA Class III and peak VO2, echocardiography and NT-proBNP data consistent with moderate to severe heart failure. The age-matched controls included were allowed hypertension but sub-clinical heart failure was to have been ruled out by normal peak VO2, echocardiography and NT-proBNP. RESULTS Exercise capacity (VO2max) differed by almost 2-fold between heart failure patients and age-matched controls. Compared with controls, skeletal muscle RyR1 in heart failure patients was excessively phosphorylated, S-nitrosylated and oxidized. Furthermore, RyR1 from heart failure patients was depleted of its stabilizing protein FK 506-binding protein 12 (FKBP12, or calstabin1). CONCLUSIONS For the first time we show that skeletal muscle RyR1 from human heart failure is post-translationally modified, which corroborates previous data from experimental animal studies. This indicates pathologic Ca2+ release as a potential mechanism behind skeletal muscle weakness and impaired exercise tolerance in patients with heart failure and suggests a potential target for pharmacologic intervention.
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Pinho-Gomes AC, Reilly S, Brandes RP, Casadei B. Targeting inflammation and oxidative stress in atrial fibrillation: role of 3-hydroxy-3-methylglutaryl-coenzyme a reductase inhibition with statins. Antioxid Redox Signal 2014; 20:1268-85. [PMID: 23924190 PMCID: PMC3934546 DOI: 10.1089/ars.2013.5542] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
SIGNIFICANCE Atrial fibrillation (AF) is a burgeoning health-care problem, and the currently available therapeutic armamentarium is barely efficient. Experimental and clinical evidence implicates inflammation and myocardial oxidative stress in the pathogenesis of AF. RECENT ADVANCES Local and systemic inflammation has been found to both precede and follow the new onset of AF, and NOX2-dependent generation of reactive oxygen species in human right atrial samples has been independently associated with the occurrence of AF in the postoperative period in patients undergoing cardiac surgery. Anti-inflammatory and antioxidant agents can prevent atrial electrical remodeling in animal models of atrial tachypacing and the new onset of AF after cardiac surgery, suggesting a causal relationship between inflammation/oxidative stress and the atrial substrate that supports AF. CRITICAL ISSUES Statin therapy, by redressing the myocardial nitroso-redox balance and reducing inflammation, has emerged as a potentially effective strategy for the prevention of AF. Evidence indicates that statins prevent AF-induced electrical remodeling in animal models of atrial tachypacing and may reduce the new onset of AF after cardiac surgery. However, whether statins have antiarrhythmic properties in humans has yet to be conclusively demonstrated, as data from randomized controlled trials specifically addressing the relevance of statin therapy for the primary and secondary prevention of AF remain scanty. FUTURE DIRECTIONS A better understanding of the mechanisms underpinning the putative antiarrhythmic effects of statins may afford tailoring AF treatment to specific clinical settings and patient's subgroups. Large-scale randomized clinical trials are needed to support the indication of statin therapy solely on the basis of AF prevention.
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Affiliation(s)
- Ana Catarina Pinho-Gomes
- 1 Department of Cardiovascular Medicine, University of Oxford , John Radcliffe Hospital, Oxford, United Kingdom
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Chen H, Mustafi SM, LeMaster DM, Li Z, Héroux A, Li H, Hernández G. Crystal structure and conformational flexibility of the unligated FK506-binding protein FKBP12.6. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:636-46. [PMID: 24598733 PMCID: PMC3949516 DOI: 10.1107/s1399004713032112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 11/25/2013] [Indexed: 12/15/2022]
Abstract
The primary known physiological function of FKBP12.6 involves its role in regulating the RyR2 isoform of ryanodine receptor Ca(2+) channels in cardiac muscle, pancreatic β islets and the central nervous system. With only a single previously reported X-ray structure of FKBP12.6, bound to the immunosuppressant rapamycin, structural inferences for this protein have been drawn from the more extensive studies of the homologous FKBP12. X-ray structures at 1.70 and 1.90 Å resolution from P2₁ and P3₁21 crystal forms are reported for an unligated cysteine-free variant of FKBP12.6 which exhibit a notable diversity of conformations. In one monomer from the P3₁21 crystal form, the aromatic ring of Phe59 at the base of the active site is rotated perpendicular to its typical orientation, generating a steric conflict for the immunosuppressant-binding mode. The peptide unit linking Gly89 and Val90 at the tip of the protein-recognition `80s loop' is flipped in the P2₁ crystal form. Unlike the >30 reported FKBP12 structures, the backbone conformation of this loop closely follows that of the first FKBP domain of FKBP51. The NMR resonances for 21 backbone amides of FKBP12.6 are doubled, corresponding to a slow conformational transition centered near the tip of the 80s loop, as recently reported for 31 amides of FKBP12. The comparative absence of doubling for residues along the opposite face of the active-site pocket in FKBP12.6 may in part reflect attenuated structural coupling owing to increased conformational plasticity around the Phe59 ring.
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Affiliation(s)
- Hui Chen
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201, USA
| | - Sourajit M. Mustafi
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201, USA
| | - David M. LeMaster
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany – SUNY, Empire State Plaza, Albany, NY 12201, USA
| | - Zhong Li
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201, USA
| | - Annie Héroux
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Hongmin Li
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany – SUNY, Empire State Plaza, Albany, NY 12201, USA
| | - Griselda Hernández
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany – SUNY, Empire State Plaza, Albany, NY 12201, USA
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127
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Zima AV, Bovo E, Mazurek SR, Rochira JA, Li W, Terentyev D. Ca handling during excitation-contraction coupling in heart failure. Pflugers Arch 2014; 466:1129-37. [PMID: 24515294 DOI: 10.1007/s00424-014-1469-3] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 01/29/2014] [Accepted: 01/30/2014] [Indexed: 12/22/2022]
Abstract
In the heart, coupling between excitation of the surface membrane and activation of contractile apparatus is mediated by Ca released from the sarcoplasmic reticulum (SR). Several components of Ca machinery are perfectly arranged within the SR network and the T-tubular system to generate a regular Ca cycling and thereby rhythmic beating activity of the heart. Among these components, ryanodine receptor (RyR) and SR Ca ATPase (SERCA) complexes play a particularly important role and their dysfunction largely underlies abnormal Ca homeostasis in diseased hearts such as in heart failure. The abnormalities in Ca regulation occur at practically all main steps of Ca cycling in the failing heart, including activation and termination of SR Ca release, diastolic SR Ca leak, and SR Ca uptake. The contributions of these different mechanisms to depressed contractile function and enhanced arrhythmogenesis may vary in different HF models. This brief review will therefore focus on modifications in RyR and SERCA structure that occur in the failing heart and how these molecular modifications affect SR Ca regulation and excitation-contraction coupling.
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Affiliation(s)
- Aleksey V Zima
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, 2160 South First Avenue, Maywood, IL, 60153, USA,
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128
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Mattiazzi A, Kranias EG. The role of CaMKII regulation of phospholamban activity in heart disease. Front Pharmacol 2014; 5:5. [PMID: 24550830 PMCID: PMC3913884 DOI: 10.3389/fphar.2014.00005] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 01/07/2014] [Indexed: 01/06/2023] Open
Abstract
Phospholamban (PLN) is a phosphoprotein in cardiac sarcoplasmic reticulum (SR) that is a reversible regulator of the Ca2+-ATPase (SERCA2a) activity and cardiac contractility. Dephosphorylated PLN inhibits SERCA2a and PLN phosphorylation, at either Ser16 by PKA or Thr17 by Ca2+-calmodulin-dependent protein kinase (CaMKII), reverses this inhibition. Through this mechanism, PLN is a key modulator of SR Ca2+ uptake, Ca2+ load, contractility, and relaxation. PLN phosphorylation is also the main determinant of β1-adrenergic responses in the heart. Although phosphorylation of Thr17 by CaMKII contributes to this effect, its role is subordinate to the PKA-dependent increase in cytosolic Ca2+, necessary to activate CaMKII. Furthermore, the effects of PLN and its phosphorylation on cardiac function are subject to additional regulation by its interacting partners, the anti-apoptotic HAX-1 protein and Gm or the anchoring unit of protein phosphatase 1. Regulation of PLN activity by this multimeric complex becomes even more important in pathological conditions, characterized by aberrant Ca2+-cycling. In this scenario, CaMKII-dependent PLN phosphorylation has been associated with protective effects in both acidosis and ischemia/reperfusion. However, the beneficial effects of increasing SR Ca2+ uptake through PLN phosphorylation may be lost or even become deleterious, when these occur in association with alterations in SR Ca2+ leak. Moreover, a major characteristic in human and experimental heart failure (HF) is depressed SR Ca2+ uptake, associated with decreased SERCA2a levels and dephosphorylation of PLN, leading to decreased SR Ca2+ load and impaired contractility. Thus, the strategy of altering SERCA2a and/or PLN levels or activity to restore perturbed SR Ca2+ uptake is a potential therapeutic tool for HF treatment. We will review here the role of CaMKII-dependent phosphorylation of PLN at Thr17 on cardiac function under physiological and pathological conditions.
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Affiliation(s)
- Alicia Mattiazzi
- Facultad de Medicina, Centro de Investigaciones Cardiovasculares, Conicet La Plata-Universidad Nacional de La Plata La Plata, Argentina
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati Cincinnati, OH, USA
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129
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Liu B, Ho HT, Velez-Cortes F, Lou Q, Valdivia CR, Knollmann BC, Valdivia HH, Gyorke S. Genetic ablation of ryanodine receptor 2 phosphorylation at Ser-2808 aggravates Ca(2+)-dependent cardiomyopathy by exacerbating diastolic Ca2+ release. J Physiol 2014; 592:1957-73. [PMID: 24445321 DOI: 10.1113/jphysiol.2013.264689] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Phosphorylation of the cardiac ryanodine receptor (RyR2) by protein kinase A (PKA) at Ser-2808 is suggested to mediate the physiological 'fight or flight' response and contribute to heart failure by rendering the sarcoplasmic reticulum (SR) leaky for Ca(2+). In the present study, we examined the potential role of RyR2 phosphorylation at Ser-2808 in the progression of Ca(2+)-dependent cardiomyopathy (CCM) by using mice genetically modified to feature elevated SR Ca(2+) leak while expressing RyR2s that cannot be phosphorylated at this site (S2808A). Surprisingly, rather than alleviating the disease phenotype, constitutive dephosphorylation of Ser-2808 aggravated CCM as manifested by shortened survival, deteriorated in vivo cardiac function, exacerbated SR Ca(2+) leak and mitochondrial injury. Notably, the deteriorations of cardiac function, myocyte Ca(2+) handling, and mitochondria integrity were consistently worse in mice with heterozygous ablation of Ser-2808 than in mice with complete ablation. Wild-type (WT) and CCM myocytes expressing unmutated RyR2s exhibited a high level of baseline phosphorylation at Ser-2808. Exposure of these CCM cells to protein phosphatase 1 caused a transitory increase in Ca(2+) leak attributable to partial dephosphorylation of RyR2 tetramers at Ser-2808 from more fully phosphorylated state. Thus, exacerbated Ca(2+) leak through partially dephosphorylated RyR2s accounts for the prevalence of the disease phenotype in the heterozygous S2808A CCM mice. These results do not support the importance of RyR2 hyperphosphorylation in Ca(2+)-dependent heart disease, and rather suggest roles for the opposite process, the RyR2 dephosphorylation at this residue in physiological and pathophysiological Ca(2+) signalling.
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Affiliation(s)
- Bin Liu
- Department of Physiology and Cell Biology, 507 Davis Heart & Lung Research Institute (office), 473 W. 12th Avenue, Columbus, OH 43210, USA.
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130
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Zamiri N, Massé S, Ramadeen A, Kusha M, Hu X, Azam MA, Liu J, Lai PFH, Vigmond EJ, Boyle PM, Behradfar E, Al-Hesayen A, Waxman MB, Backx P, Dorian P, Nanthakumar K. Dantrolene improves survival after ventricular fibrillation by mitigating impaired calcium handling in animal models. Circulation 2014; 129:875-85. [PMID: 24403563 DOI: 10.1161/circulationaha.113.005443] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Resistant ventricular fibrillation, refibrillation. and diminished myocardial contractility are important factors leading to poor survival after cardiac arrest. We hypothesized that dantrolene improves survival after ventricular fibrillation (VF) by rectifying the calcium dysregulation caused by VF. METHODS AND RESULTS VF was induced in 26 Yorkshire pigs for 4 minutes. Cardiopulmonary resuscitation was then commenced for 3 minutes, and dantrolene or isotonic saline was infused at the onset of cardiopulmonary resuscitation. Animals were defibrillated and observed for 30 minutes. To study the effect of VF on calcium handling and its modulation by dantrolene, hearts from 14 New Zealand rabbits were Langendorff-perfused. The inducibility of VF after dantrolene administration was documented. Optical mapping was performed to evaluate diastolic spontaneous calcium elevations as a measure of cytosolic calcium leak. The sustained return of spontaneous circulation (systolic blood pressure ≥60 mm Hg) was achieved in 85% of the dantrolene group in comparison with 39% of controls (P=0.02). return of spontaneous circulation was achieved earlier in dantrolene-treated pigs after successful defibrillation (21 ± 6 s versus 181 ± 57 s in controls, P=0.005). The median number of refibrillation episodes was lower in the dantrolene group (0 versus 1, P=0.04). In isolated rabbit hearts, the successful induction of VF was achieved in 83% of attempts in controls versus 41% in dantrolene-treated hearts (P=0.007). VF caused diastolic calcium leaks in the form of spontaneous calcium elevations. Administration of 20 μmol/L dantrolene significantly decreased spontaneous calcium elevation amplitude versus controls. (0.024 ± 0.013 versus 0.12 ± 0.02 arbitrary unit [200-ms cycle length], P=0.001). CONCLUSIONS Dantrolene infusion during cardiopulmonary resuscitation facilitates successful defibrillation, improves hemodynamics postdefibrillation, decreases refibrillation, and thus improves survival after cardiac arrest. The effects are mediated through normalizing VF-induced dysfunctional calcium cycling.
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Affiliation(s)
- Nima Zamiri
- From The Hull Family Cardiac Fibrillation Management Laboratory, University Health Network, University of Toronto, Toronto, ON, Canada (A.M., N.Z., S.M., M.K., M.A.A, P.F.H.L., M.B.W., K.N.); Keenan Research Centre, Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, ON, Canada (A.R., X.H., A.A.-H., P.D.); Institute of Medical Science, University of Toronto, Toronto, ON, Canada (N.Z.); Department of Physiology, University of Toronto, Toronto, ON, Canada (J.L., P.B.); Institute LIRYC, Université Bordeaux 1, Bordeaux, France (E.J.V.); Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD (P.M.B.); and Department of Electrical Engineering, University of Calgary, Calgary, AB, Canada (E.B.)
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131
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Lehmann LH, Worst BC, Stanmore DA, Backs J. Histone deacetylase signaling in cardioprotection. Cell Mol Life Sci 2013; 71:1673-90. [PMID: 24310814 PMCID: PMC3983897 DOI: 10.1007/s00018-013-1516-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/23/2013] [Accepted: 11/07/2013] [Indexed: 12/17/2022]
Abstract
Cardiovascular disease (CVD) represents a major challenge for health care systems, both in terms of the high mortality associated with it and the huge economic burden of its treatment. Although CVD represents a diverse range of disorders, they share common compensatory changes in the heart at the structural, cellular, and molecular level that, in the long term, can become maladaptive and lead to heart failure. Treatment of adverse cardiac remodeling is therefore an important step in preventing this fatal progression. Although previous efforts have been primarily focused on inhibition of deleterious signaling cascades, the stimulation of endogenous cardioprotective mechanisms offers a potent therapeutic tool. In this review, we discuss class I and class II histone deacetylases, a subset of chromatin-modifying enzymes known to have critical roles in the regulation of cardiac remodeling. In particular, we discuss their molecular modes of action and go on to consider how their inhibition or the stimulation of their intrinsic cardioprotective properties may provide a potential therapeutic route for the clinical treatment of CVD.
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Affiliation(s)
- Lorenz H. Lehmann
- Research Unit Cardiac Epigenetics, Internal Medicine III, Heidelberg University and DZHK (German Center for Cardiovascular Research), partner site Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Barbara C. Worst
- Research Unit Cardiac Epigenetics, Internal Medicine III, Heidelberg University and DZHK (German Center for Cardiovascular Research), partner site Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - David A. Stanmore
- Research Unit Cardiac Epigenetics, Internal Medicine III, Heidelberg University and DZHK (German Center for Cardiovascular Research), partner site Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Johannes Backs
- Research Unit Cardiac Epigenetics, Internal Medicine III, Heidelberg University and DZHK (German Center for Cardiovascular Research), partner site Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
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132
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Abstract
Synchronized SR calcium (Ca) release is critical to normal cardiac myocyte excitation-contraction coupling, and ideally this release shuts off completely between heartbeats. However, other SR Ca release events are referred to collectively as SR Ca leak (which includes Ca sparks and waves as well as smaller events not detectable as Ca sparks). Much, but not all, of the SR Ca leak occurs via ryanodine receptors and can be exacerbated in pathological states such as heart failure. The extent of SR Ca leak is important because it can (a) reduce SR Ca available for release, causing systolic dysfunction; (b) elevate diastolic [Ca]i, contributing to diastolic dysfunction; (c) cause triggered arrhythmias; and (d) be energetically costly because of extra ATP used to repump Ca. This review addresses quantitative aspects and manifestations of SR Ca leak and its measurement, and how leak is modulated by Ca, associated proteins, and posttranslational modifications in health and disease.
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Affiliation(s)
- Donald M Bers
- Department of Pharmacology, University of California, Davis, California 95616;
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133
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Høydal MA, Kaurstad G, Rolim NP, Johnsen AB, Alves M, Koch LG, Britton SL, Stølen TO, Smith GL, Wisløff U. High inborn aerobic capacity does not protect the heart following myocardial infarction. J Appl Physiol (1985) 2013; 115:1788-95. [PMID: 24177693 DOI: 10.1152/japplphysiol.00312.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Maximal oxygen uptake (Vo2max) is a strong prognostic marker for morbidity and mortality, but the cardio-protective effect of high inborn Vo2max remains unresolved. We aimed to investigate whether rats with high inborn Vo2max yield cardio-protection after myocardial infarction (MI) compared with rats with low inborn Vo2max. Rats breed for high capacity of running (HCR) or low capacity of running (LCR) were randomized into HCR-SH (sham), HCR-MI, LCR-SH, and LCR-MI. Vo2max was lower in HCR-MI and LCR-MI compared with respective sham (P < 0.01), supported by a loss in global cardiac function, assessed by echocardiography. Fura 2-AM loaded cardiomyocyte experiments revealed that HCR-MI and LCR-MI decreased cardiomyocyte shortening (39%, and 34% reduction, respectively, both P < 0.01), lowered Ca(2+) transient amplitude (37%, P < 0.01, and 20% reduction, respectively), and reduced sarcoplasmic reticulum (SR) Ca(2+) content (both; 20%, P < 0.01) compared with respective sham. Diastolic Ca(2+) cycling was impaired in HCR-MI and LCR-MI evidenced by prolonged time to 50% Ca(2+) decay that was partly explained by the 47% (P < 0.01) and 44% (P < 0.05) decrease in SR Ca(2+)-ATPase Ca(2+) removal, respectively. SR Ca(2+) leak increased by 177% in HCR-MI (P < 0.01) and 67% in LCR-MI (P < 0.01), which was abolished by inhibition of Ca(2+)/calmodulin-dependent protein kinase II. This study demonstrates that the effect of MI in HCR rats was similar or even more pronounced on cardiac- and cardiomyocyte contractile function, as well as on Ca(2+) handling properties compared with observations in LCR. Thus our data do not support a cardio-protective effect of higher inborn aerobic capacity.
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Affiliation(s)
- M A Høydal
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
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134
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Huang ZM, Gao E, Fonseca FV, Hayashi H, Shang X, Hoffman NE, Chuprun JK, Tian X, Tilley DG, Madesh M, Lefer DJ, Stamler JS, Koch WJ. Convergence of G protein-coupled receptor and S-nitrosylation signaling determines the outcome to cardiac ischemic injury. Sci Signal 2013; 6:ra95. [PMID: 24170934 DOI: 10.1126/scisignal.2004225] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Heart failure caused by ischemic heart disease is a leading cause of death in the developed world. Treatment is currently centered on regimens involving G protein-coupled receptors (GPCRs) or nitric oxide (NO). These regimens are thought to target distinct molecular pathways. We showed that these pathways were interdependent and converged on the effector GRK2 (GPCR kinase 2) to regulate myocyte survival and function. Ischemic injury coupled to GPCR activation, including GPCR desensitization and myocyte loss, required GRK2 activation, and we found that cardioprotection mediated by inhibition of GRK2 depended on endothelial nitric oxide synthase (eNOS) and was associated with S-nitrosylation of GRK2. Conversely, the cardioprotective effects of NO bioactivity were absent in a knock-in mouse with a form of GRK2 that cannot be S-nitrosylated. Because GRK2 and eNOS inhibit each other, the balance of the activities of these enzymes in the myocardium determined the outcome to ischemic injury. Our findings suggest new insights into the mechanism of action of classic drugs used to treat heart failure and new therapeutic approaches to ischemic heart disease.
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Affiliation(s)
- Z Maggie Huang
- 1Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
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135
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Abstract
Ca²⁺ plays a crucial role in connecting membrane excitability with contraction in myocardium. The hallmark features of heart failure are mechanical dysfunction and arrhythmias; defective intracellular Ca²⁺ homeostasis is a central cause of contractile dysfunction and arrhythmias in failing myocardium. Defective Ca²⁺ homeostasis in heart failure can result from pathological alteration in the expression and activity of an increasingly understood collection of Ca²⁺ homeostatic and structural proteins, ion channels, and enzymes. This review focuses on the molecular mechanisms of defective Ca²⁺ cycling in heart failure and considers how fundamental understanding of these pathways may translate into novel and innovative therapies.
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Affiliation(s)
- Min Luo
- Division of Cardiovascular Medicine, Department of Internal Medicine, Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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136
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Singh VP, Rubinstein J, Arvanitis DA, Ren X, Gao X, Haghighi K, Gilbert M, Iyer VR, Kim DH, Cho C, Jones K, Lorenz JN, Armstrong CF, Wang HS, Gyorke S, Kranias EG. Abnormal calcium cycling and cardiac arrhythmias associated with the human Ser96Ala genetic variant of histidine-rich calcium-binding protein. J Am Heart Assoc 2013; 2:e000460. [PMID: 24125847 PMCID: PMC3835262 DOI: 10.1161/jaha.113.000460] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND A human genetic variant (Ser96Ala) in the sarcoplasmic reticulum (SR) histidine-rich Ca(2+)-binding (HRC) protein has been linked to ventricular arrhythmia and sudden death in dilated cardiomyopathy. However, the precise mechanisms affecting SR function and leading to arrhythmias remain elusive. METHODS AND RESULTS We generated transgenic mice with cardiac-specific expression of human Ala96 HRC or Ser96 HRC in the null background to assess function in absence of endogenous protein. Ala96 HRC decreased (25% to 30%) cardiomyocyte contractility and Ca2+ kinetics compared with Ser96 HRC in the absence of any structural or histological abnormalities. Furthermore, the frequency of Ca2+ waves was significantly higher (10-fold), although SR Ca2+ load was reduced (by 27%) in Ala96 HRC cells. The underlying mechanisms involved diminished interaction of Ala96 HRC with triadin, affecting ryanodine receptor (RyR) stability. Indeed, the open probability of RyR, assessed by use of ryanodine binding, was significantly increased. Accordingly, stress conditions (5 Hz plus isoproterenol) induced aftercontractions (65% in Ala96 versus 12% in Ser96) and delayed afterdepolarizations (70% in Ala96 versus 20% in Ser96). The increased SR Ca2+ leak was accompanied by hyperphosphorylation (1.6-fold) of RyR at Ser2814 by calmodulin-dependent protein kinase II. Accordingly, inclusion of the calmodulin-dependent protein kinase II inhibitor KN93 prevented Ser2814 phosphorylation and partially reversed the increases in Ca2+ spark frequency and wave production. Parallel in vivo studies revealed ventricular ectopy on short-term isoproterenol challenge and increased (4-fold) propensity to arrhythmias, including nonsustained ventricular tachycardia, after myocardial infarction in Ala96 HRC mice. CONCLUSIONS These findings suggest that aberrant SR Ca2+ release and increased susceptibility to delayed afterdepolarizations underlie triggered arrhythmic activity in human Ala96 HRC carriers.
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Affiliation(s)
- Vivek P Singh
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH
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137
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Fischer TH, Herting J, Tirilomis T, Renner A, Neef S, Toischer K, Ellenberger D, Förster A, Schmitto JD, Gummert J, Schöndube FA, Hasenfuss G, Maier LS, Sossalla S. Ca
2+
/Calmodulin-Dependent Protein Kinase II and Protein Kinase A Differentially Regulate Sarcoplasmic Reticulum Ca
2+
Leak in Human Cardiac Pathology. Circulation 2013; 128:970-81. [DOI: 10.1161/circulationaha.113.001746] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Sarcoplasmic reticulum (SR) Ca
2+
leak through ryanodine receptor type 2 (RyR2) dysfunction is of major pathophysiological relevance in human heart failure (HF); however, mechanisms underlying progressive RyR2 dysregulation from cardiac hypertrophy to HF are still controversial.
Methods and Results—
We investigated healthy control myocardium (n=5) and myocardium from patients with compensated hypertrophy (n=25) and HF (n=32). In hypertrophy, Ca
2+
/calmodulin-dependent protein kinase II (CaMKII) and protein kinase A (PKA) both phosphorylated RyR2 at levels that were not different from healthy myocardium. Accordingly, inhibitors of these kinases reduced the SR Ca
2+
leak. In HF, however, the SR Ca
2+
leak was nearly doubled compared with hypertrophy, which led to reduced systolic Ca
2+
transients, a depletion of SR Ca
2+
storage and elevated diastolic Ca
2+
levels. This was accompanied by a significantly increased CaMKII-dependent phosphorylation of RyR2. In contrast, PKA-dependent RyR2 phosphorylation was not increased in HF and was independent of previous β-blocker treatment. In HF, CaMKII inhibition but not inhibition of PKA yielded a reduction of the SR Ca
2+
leak. Moreover, PKA inhibition further reduced SR Ca
2+
load and systolic Ca
2+
transients.
Conclusions—
In human hypertrophy, both CaMKII and PKA functionally regulate RyR2 and may induce SR Ca
2+
leak. In the transition from hypertrophy to HF, the diastolic Ca
2+
leak increases and disturbed Ca
2+
cycling occurs. This is associated with an increase in CaMKII- but not PKA-dependent RyR2 phosphorylation. CaMKII inhibition may thus reflect a promising therapeutic target for the treatment of arrhythmias and contractile dysfunction.
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Affiliation(s)
- Thomas H. Fischer
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Jonas Herting
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Theodor Tirilomis
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - André Renner
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Stefan Neef
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Karl Toischer
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - David Ellenberger
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Anna Förster
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Jan D. Schmitto
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Jan Gummert
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Friedrich A. Schöndube
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Gerd Hasenfuss
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Lars S. Maier
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
| | - Samuel Sossalla
- From Abteilung Kardiologie und Pneumologie/Herzzentrum (T.H.F., J.H., S.N., K.T., A.F., G.H., L.S.M., S.S.), Abteilung Thorax, Herz, Gefäßchirurgie/Herzzentrum (T.T., F.A.S.), and Abteilung Medizinische Statistik (D.E.), Georg August Universität Göttingen, Göttingen, Germany; Abteilung Thorax, Herz, Gefäßchirurgie, Herz und Diabeteszentrum Nordrheinwestfalen, Bad Oeynhausen, Germany (A.R., J.G.); Abteilung Herz, Thorax, Gefäßchirurgie und Transplantationschirurgie, Medizinische Hochschule Hannover,
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138
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Gutierrez DA, Fernandez-Tenorio M, Ogrodnik J, Niggli E. NO-dependent CaMKII activation during β-adrenergic stimulation of cardiac muscle. Cardiovasc Res 2013; 100:392-401. [PMID: 23963842 DOI: 10.1093/cvr/cvt201] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS During β-adrenergic receptor (β-AR) stimulation, phosphorylation of cardiomyocyte ryanodine receptors by protein kinases may contribute to an increased diastolic Ca(2+) spark frequency. Regardless of prompt activation of protein kinase A during β-AR stimulation, this appears to rely more on activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), by a not yet identified signalling pathway. The goal of the present study was to identify and characterize the mechanisms which lead to CaMKII activation and elevated Ca(2+) spark frequencies during β-AR stimulation in single cardiomyocytes in diastolic conditions. METHODS AND RESULTS Confocal imaging revealed that β-AR stimulation increases endogenous NO production in cardiomyocytes, resulting in NO-dependent activation of CaMKII and a subsequent increase in diastolic Ca(2+) spark frequency. These changes of spark frequency could be mimicked by exposure to the NO donor GSNO and were sensitive to the CaMKII inhibitors KN-93 and AIP. In vitro, CaMKII became nitrosated and its activity remained increased independent of Ca(2+) in the presence of GSNO, as assessed with biochemical assays. CONCLUSIONS β-AR stimulation of cardiomyocytes may activate CaMKII by a novel direct pathway involving NO, without requiring Ca(2+) transients. This crosstalk between two established signalling pathways may contribute to arrhythmogenic diastolic Ca(2+) release and Ca(2+) waves during adrenergic stress, particularly in combination with cardiac diseases. In addition, NO-dependent activation of CaMKII is likely to have repercussions in many cellular signalling systems and cell types.
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Affiliation(s)
- Daniel A Gutierrez
- Department of Physiology, University of Bern, Bühlplatz 5, CH-3012 Bern, Switzerland
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139
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Affiliation(s)
- Eugene Braunwald
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.
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140
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Yi T, Vick JS, Vecchio MJH, Begin KJ, Bell SP, Delay RJ, Palmer BM. Identifying cellular mechanisms of zinc-induced relaxation in isolated cardiomyocytes. Am J Physiol Heart Circ Physiol 2013; 305:H706-15. [PMID: 23812383 DOI: 10.1152/ajpheart.00025.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We tested several molecular and cellular mechanisms of cardiomyocyte contraction-relaxation function that could account for the reduced systolic and enhanced diastolic function observed with exposure to extracellular Zn(2+). Contraction-relaxation function was monitored in isolated rat and mouse cardiomyocytes maintained at 37°C, stimulated at 2 or 6 Hz, and exposed to 32 μM Zn(2+) or vehicle. Intracellular Zn(2+) detected using FluoZin-3 rose to a concentration of ∼13 nM in 3-5 min. Peak sarcomere shortening was significantly reduced and diastolic sarcomere length was elongated after Zn(2+) exposure. Peak intracellular Ca(2+) detected by Fura-2FF was reduced after Zn(2+) exposure. However, the rate of cytosolic Ca(2+) decline reflecting sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2a) activity and the rate of Na(+)/Ca(2+) exchanger activity evaluated by rapid Na(+)-induced Ca(2+) efflux were unchanged by Zn(2+) exposure. SR Ca(2+) load evaluated by rapid caffeine exposure was reduced by ∼50%, and L-type calcium channel inward current measured by whole cell patch clamp was reduced by ∼70% in cardiomyocytes exposed to Zn(2+). Furthermore, ryanodine receptor (RyR) S2808 and phospholamban (PLB) S16/T17 were markedly dephosphorylated after perfusing hearts with 50 μM Zn(2+). Maximum tension development and thin-filament Ca(2+) sensitivity in chemically skinned cardiac muscle strips were not affected by Zn(2+) exposure. These findings suggest that Zn(2+) suppresses cardiomyocyte systolic function and enhances relaxation function by lowering systolic and diastolic intracellular Ca(2+) concentrations due to a combination of competitive inhibition of Ca(2+) influx through the L-type calcium channel, reduction of SR Ca(2+) load resulting from phospholamban dephosphorylation, and lowered SR Ca(2+) leak via RyR dephosphorylation. The use of the low-Ca(2+)-affinity Fura-2FF likely prevented the detection of changes in diastolic Ca(2+) and SERCA2a function. Other strategies to detect diastolic Ca(2+) in the presence of Zn(2+) are essential for future work.
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Affiliation(s)
- Ting Yi
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont
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141
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Ather S, Respress JL, Li N, Wehrens XHT. Alterations in ryanodine receptors and related proteins in heart failure. Biochim Biophys Acta Mol Basis Dis 2013; 1832:2425-31. [PMID: 23770282 DOI: 10.1016/j.bbadis.2013.06.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 04/23/2013] [Accepted: 06/05/2013] [Indexed: 01/07/2023]
Abstract
Sarcoplasmic reticulum (SR) Ca(2+) release plays an essential role in mediating cardiac myocyte contraction. Depolarization of the plasma membrane results in influx of Ca(2+) through l-type Ca(2+) channels (LTCCs) that in turn triggers efflux of Ca(2+) from the SR through ryanodine receptor type-2 channels (RyR2). This process known as Ca(2+)-induced Ca(2+)release (CICR) occurs within the dyadic region, where the adjacent transverse (T)-tubules and SR membranes allow RyR2 clusters to release SR Ca(2+) following Ca(2+) influx through adjacent LTCCs. SR Ca(2+) released during systole binds to troponin-C and initiates actin-myosin cross-bridging, leading to muscle contraction. During diastole, the cytosolic Ca(2+) concentration is restored by the resequestration of Ca(2+) into the SR by SR/ER Ca(2+)-ATPase (SERCA2a) and by the extrusion of Ca(2+) via the Na(+)/Ca(2+)-exchanger (NCX1). This whole process, entitled excitation-contraction (EC) coupling, is highly coordinated and determines the force of contraction, providing a link between the electrical and mechanical activities of cardiac muscle. In response to heart failure (HF), the heart undergoes maladaptive changes that result in depressed intracellular Ca(2+) cycling and decreased SR Ca(2+) concentrations. As a result, the amplitude of CICR is reduced resulting in less force production during EC coupling. In this review, we discuss the specific proteins that alter the regulation of Ca(2+) during HF. In particular, we will focus on defects in RyR2-mediated SR Ca(2+) release. This article is part of a Special Issue entitled: Heart failure pathogenesis and emerging diagnostic and therapeutic interventions.
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Affiliation(s)
- Sameer Ather
- Dept of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA; Dept of Medicine (Cardiology), Baylor College of Medicine, Houston, TX, USA
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142
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Neef S, Maier LS. Novel aspects of excitation-contraction coupling in heart failure. Basic Res Cardiol 2013; 108:360. [PMID: 23740218 DOI: 10.1007/s00395-013-0360-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/18/2013] [Accepted: 03/28/2013] [Indexed: 12/19/2022]
Abstract
Excitation-contraction coupling is the process by which electrical activation is translated into contraction of a cardiac myocyte and thus the heart. In heart failure, expression, phosphorylation, and function of several intracellular proteins that are involved in excitation-contraction coupling are altered. The present review article summarizes central principles and highlights novel aspects of alterations in heart failure, focusing especially on recent findings regarding altered sarcoplasmic reticulum Ca2+ -leak and late Na+ -current without being able to cover all changes in full detail. These two pathomechanisms seem to play interesting roles with respect to systolic and diastolic dysfunction and may also be important for cardiac arrhythmias. Furthermore, the article outlines the translation of these novel findings into potential therapeutic approaches.
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Affiliation(s)
- Stefan Neef
- Abt. Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
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143
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Fauconnier J, Roberge S, Saint N, Lacampagne A. Type 2 ryanodine receptor: A novel therapeutic target in myocardial ischemia/reperfusion. Pharmacol Ther 2013; 138:323-32. [DOI: 10.1016/j.pharmthera.2013.01.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 01/22/2013] [Indexed: 10/27/2022]
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144
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Perera RK, Nikolaev VO. Compartmentation of cAMP signalling in cardiomyocytes in health and disease. Acta Physiol (Oxf) 2013; 207:650-62. [PMID: 23383621 DOI: 10.1111/apha.12077] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 11/27/2012] [Accepted: 01/30/2013] [Indexed: 12/13/2022]
Abstract
3',5'-cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger critically involved in the regulation of heart function. It has been shown to act in discrete subcellular signalling compartments formed by differentially localized receptors, phosphodiesterases and protein kinases. Cardiac diseases such as hypertrophy or heart failure are associated with structural and functional remodelling of these microdomains which leads to changes in cAMP compartmentation. In this review, we will discuss recent key findings which provided new insights into cAMP compartmentation in cardiomyocytes with a particular focus on its alterations in heart disease.
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Affiliation(s)
- R. K. Perera
- Emmy Noether Group of the DFG, Department of Cardiology and Pneumology, European Heart Research Insitute Göttingen, Georg August University Medical Center; University of Göttingen; Göttingen; Germany
| | - V. O. Nikolaev
- Emmy Noether Group of the DFG, Department of Cardiology and Pneumology, European Heart Research Insitute Göttingen, Georg August University Medical Center; University of Göttingen; Göttingen; Germany
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145
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Ma Q, Luo Y, Guo P, Gao G, Yang M, Sablok G, Zhang Y, Zhou F. Clinical effects of Xinmailong therapy in patients with chronic heart failure. Int J Med Sci 2013; 10:624-33. [PMID: 23569425 PMCID: PMC3619101 DOI: 10.7150/ijms.5779] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 03/11/2013] [Indexed: 01/24/2023] Open
Abstract
In the last 100 years, intensive studies have been done on the identification of the systematic approaches to find the cure for the chronic heart failure, however the mystery remains unresolved due to its complicated pathogenesis and ineffective early diagnosis. The present investigation was aimed to evaluate the potential effects of the traditional chinese medicine, Xinmailong, on the chronic heart failure (CHF) patients as compared to the standard western medical treatment available so far. In our study, we selected two groups of voluntary CHF patients at the Xiangya Hospital, which were allowed to administrate Xinmailong or standard treatments, respectively. Another group of voluntary healthy individuals were recruited as the control group. The treatment effectiveness was measured by five symptomatic factors, i.e. angiotensin II (Ang_II), high sensitivity C-reactive protein (hs_CRP), Left Ventricular End Systolic Volume Index (LVESVI), left ventricular ejection fraction (LVEF) and pro-B-type natriuretic peptide (NT_proBNP), between the control group and the CHF patients at different stages of drug administration and in different treatment groups. The timeline for the full dose administration was set to 15 days and five measurements as indicated above were taken on every 0, 7th and 15th day of the drug administration respectively. In the conducted study, similar symptomatic measurements were observed on day 0 in both treatment groups, and slight improvements were observed on 7th day. It was observed that after a full course of drug administration for 15 days, both of the treatment groups achieved statistically significant improvements in all the five measures, but Xinmailong was found to be more (almost double) statistically significant as compared with the available drug treatments for chronic heart failure.
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Affiliation(s)
- Qilin Ma
- 2. Cardiovascular Internal Department, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China, 410008
| | - Youxi Luo
- 1. Shenzhen Institutes of Advanced Technology, and Key Laboratory of Health Informatics, Chinese Academy of Sciences, Shenzhen, Guangdong, P.R. China, 518055
| | - Pi Guo
- 1. Shenzhen Institutes of Advanced Technology, and Key Laboratory of Health Informatics, Chinese Academy of Sciences, Shenzhen, Guangdong, P.R. China, 518055
- 3. Department of Public Health, Shantou University Medical College, No. 22 Xinling Road, Shantou, Guangdong, P.R. China, 515041
| | - Gan Gao
- 2. Cardiovascular Internal Department, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China, 410008
| | - Meixue Yang
- 1. Shenzhen Institutes of Advanced Technology, and Key Laboratory of Health Informatics, Chinese Academy of Sciences, Shenzhen, Guangdong, P.R. China, 518055
| | - Gaurav Sablok
- 4. Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010 S. Michele all'Adige (TN), Italy
| | - Yanchun Zhang
- 5. Centre for Applied Informatics, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne , VIC 8001, Australia
- 6. Centre for Ficticious Economy and Data Science, University of Chinese Academy of Science. #305, Building 6, Zhongguancun East Road 80, Haidian District , Beijing, China 100190
| | - Fengfeng Zhou
- 1. Shenzhen Institutes of Advanced Technology, and Key Laboratory of Health Informatics, Chinese Academy of Sciences, Shenzhen, Guangdong, P.R. China, 518055
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146
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Marx SO, Marks AR. Dysfunctional ryanodine receptors in the heart: new insights into complex cardiovascular diseases. J Mol Cell Cardiol 2013; 58:225-31. [PMID: 23507255 DOI: 10.1016/j.yjmcc.2013.03.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/26/2013] [Accepted: 03/02/2013] [Indexed: 01/07/2023]
Abstract
Calcium dependent signaling is highly regulated in cardiomyocytes and determines the force of cardiac muscle contraction. The cardiac ryanodine receptors (RyR2) play important roles in health and disease. Modulation of RyR2 by phosphorylation is required for sympathetic regulation of cardiac function. Abnormal regulation of RyR2 contributes to heart failure, and atrial and ventricular arrhythmias. RyR2 channels are oxidized, nitrosylated, and hyperphosphorylated by protein kinase A (PKA) in heart failure, resulting in "leaky" channels. These leaky RyR2 channels contribute to depletion of calcium from the sarcoplasmic reticulum, resulting in defective cardiac excitation-contraction coupling. In this review, we discuss both the importance of PKA and calcium/calmodulin-dependent kinase II (CaMKII) regulation of RyR2 in health, and how altered phosphorylation, nitrosylation and oxidation of RyR2 channels lead to cardiac disease. Correcting these defects using either genetic manipulation (knock-in) in mice, or specific and novel small molecules ameliorates the RyR2 dysfunction, reducing the progression to heart failure and the incidence of arrhythmias.
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Affiliation(s)
- Steven O Marx
- Division of Cardiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
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147
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Abstract
Despite major improvements in the treatment of virtually all cardiac disorders, heart failure (HF) is an exception, in that its prevalence is rising, and only small prolongations in survival are occurring. An increasing fraction, especially older women with diabetes, obesity, and atrial fibrillation exhibit HF with preserved systolic function. Several pathogenetic mechanisms appear to be operative in HF. These include increased hemodynamic overload, ischemia-related dysfunction, ventricular remodeling, excessive neurohumoral stimulation, abnormal myocyte calcium cycling, excessive or inadequate proliferation of the extracellular matrix, accelerated apoptosis, and genetic mutations. Biomarkers released as a consequence of myocardial stretch, imbalance between formation and breakdown of extracellular matrix, inflammation, and renal failure are useful in the identification of the pathogenetic mechanism and, when used in combination, may become helpful in estimating prognosis and selecting appropriate therapy. Promising new therapies that are now undergoing intensive investigation include an angiotensin receptor neprilysin inhibitor, a naturally-occurring vasodilator peptide, a myofilament sensitizer and several drugs that enhance Ca++ uptake by the sarcoplasmic reticulum. Cell therapy, using autologous bone marrow and cardiac progenitor cells, appears to be promising, as does gene therapy. Chronic left ventricular assistance with continuous flow pumps is being applied more frequently and successfully as destination therapy, as a bridge to transplantation, and even as a bridge to recovery and explantation. While many of these therapies will improve the care of patients with HF, significant reductions in prevalence will require vigorous, multifaceted, preventive approaches.
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Affiliation(s)
- Eugene Braunwald
- TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital; and the Department of Medicine, Harvard Medical School, Boston, Massachusetts.
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148
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Beca S, Ahmad F, Shen W, Liu J, Makary S, Polidovitch N, Sun J, Hockman S, Chung YW, Movesian M, Murphy E, Manganiello V, Backx PH. Phosphodiesterase type 3A regulates basal myocardial contractility through interacting with sarcoplasmic reticulum calcium ATPase type 2a signaling complexes in mouse heart. Circ Res 2013; 112:289-97. [PMID: 23168336 PMCID: PMC3579621 DOI: 10.1161/circresaha.111.300003] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 11/19/2012] [Indexed: 11/16/2022]
Abstract
RATIONALE cAMP is an important regulator of myocardial function, and regulation of cAMP hydrolysis by cyclic nucleotide phosphodiesterases (PDEs) is a critical determinant of the amplitude, duration, and compartmentation of cAMP-mediated signaling. The role of different PDE isozymes, particularly PDE3A vs PDE3B, in the regulation of heart function remains unclear. OBJECTIVE To determine the relative contribution of PDE3A vs PDE3B isozymes in the regulation of heart function and to dissect the molecular basis for this regulation. METHODS AND RESULTS Compared with wild-type littermates, cardiac contractility and relaxation were enhanced in isolated hearts from PDE3A(-/-), but not PDE3B(-/-), mice. Furthermore, PDE3 inhibition had no effect on PDE3A(-/-) hearts but increased contractility in wild-type (as expected) and PDE3B(-/-) hearts to levels indistinguishable from PDE3A(-/-). The enhanced contractility in PDE3A(-/-) hearts was associated with cAMP-dependent elevations in Ca(2+) transient amplitudes and increased sarcoplasmic reticulum (SR) Ca(2+) content, without changes in L-type Ca(2+) currents of cardiomyocytes, as well as with increased SR Ca(2+)-ATPase type 2a activity, SR Ca(2+) uptake rates, and phospholamban phosphorylation in SR fractions. Consistent with these observations, PDE3 activity was reduced ≈8-fold in SR fractions from PDE3A(-/-) hearts. Coimmunoprecipitation experiments further revealed that PDE3A associates with both SR calcium ATPase type 2a and phospholamban in a complex that also contains A-kinase anchoring protein-18, protein kinase type A-RII, and protein phosphatase type 2A. CONCLUSIONS Our data support the conclusion that PDE3A is the primary PDE3 isozyme modulating basal contractility and SR Ca(2+) content by regulating cAMP in microdomains containing macromolecular complexes of SR calcium ATPase type 2a-phospholamban-PDE3A.
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Affiliation(s)
- Sanja Beca
- Department of Physiology, University of Toronto, Toronto, Ontario
| | - Faiyaz Ahmad
- The Cardiovascular Pulmonary Branch, National Heart, Lung and Blood Institute, NIH, Bethesda
| | - Weixing Shen
- The Cardiovascular Pulmonary Branch, National Heart, Lung and Blood Institute, NIH, Bethesda
| | - Jie Liu
- Department of Physiology, University of Toronto, Toronto, Ontario
| | - Samy Makary
- Department of Physiology, University of Toronto, Toronto, Ontario
- Division of Cardiology, University Health Network, Toronto, Ontario
| | | | - Junhui Sun
- Systems Biology Center, National Heart, Lung and Blood Institute, NIH, Bethesda
| | - Steven Hockman
- The Cardiovascular Pulmonary Branch, National Heart, Lung and Blood Institute, NIH, Bethesda
| | - Youn Wook Chung
- The Cardiovascular Pulmonary Branch, National Heart, Lung and Blood Institute, NIH, Bethesda
| | - Matthew Movesian
- Cardiology Section, VA Salt Lake City Health Care System, Salt Lake City, UT
| | - Elizabeth Murphy
- Systems Biology Center, National Heart, Lung and Blood Institute, NIH, Bethesda
| | - Vincent Manganiello
- The Cardiovascular Pulmonary Branch, National Heart, Lung and Blood Institute, NIH, Bethesda
| | - Peter H. Backx
- Department of Physiology, University of Toronto, Toronto, Ontario
- Department of Medicine, University of Toronto, Toronto, Ontario
- Division of Cardiology, University Health Network, Toronto, Ontario
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149
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Mei Y, Xu L, Kramer HF, Tomberlin GH, Townsend C, Meissner G. Stabilization of the skeletal muscle ryanodine receptor ion channel-FKBP12 complex by the 1,4-benzothiazepine derivative S107. PLoS One 2013; 8:e54208. [PMID: 23349825 PMCID: PMC3547879 DOI: 10.1371/journal.pone.0054208] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 12/10/2012] [Indexed: 12/12/2022] Open
Abstract
Activation of the skeletal muscle ryanodine receptor (RyR1) complex results in the rapid release of Ca2+ from the sarcoplasmic reticulum and muscle contraction. Dissociation of the small FK506 binding protein 12 subunit (FKBP12) increases RyR1 activity and impairs muscle function. The 1,4-benzothiazepine derivative JTV519, and the more specific derivative S107 (2,3,4,5,-tetrahydro-7-methoxy-4-methyl-1,4-benzothiazepine), are thought to improve skeletal muscle function by stabilizing the RyR1-FKBP12 complex. Here, we report a high degree of nonspecific and specific low affinity [3H]S107 binding to SR vesicles. SR vesicles enriched in RyR1 bound ∼48 [3H]S107 per RyR1 tetramer with EC50 ∼52 µM and Hillslope ∼2. The effects of S107 and FKBP12 on RyR1 were examined under conditions that altered the redox state of RyR1. S107 increased FKBP12 binding to RyR1 in SR vesicles in the presence of reduced glutathione and the NO-donor NOC12, with no effect in the presence of oxidized glutathione. Addition of 0.15 µM FKBP12 to SR vesicles prevented FKBP12 dissociation; however, in the presence of oxidized glutathione and NOC12, FKBP12 dissociation was observed in skeletal muscle homogenates that contained 0.43 µM myoplasmic FKBP12 and was attenuated by S107. In single channel measurements with FKBP12-depleted RyR1s, in the absence and presence of NOC12, S107 augmented the FKBP12-mediated decrease in channel activity. The data suggest that S107 can reverse the harmful effects of redox active species on SR Ca2+ release in skeletal muscle by binding to RyR1 low affinity sites.
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Affiliation(s)
- Yingwu Mei
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Le Xu
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Henning F. Kramer
- GlaxoSmithKline Research and Development, Research Triangle Park, North Carolina, United States of America
| | - Ginger H. Tomberlin
- GlaxoSmithKline Research and Development, Research Triangle Park, North Carolina, United States of America
| | - Claire Townsend
- GlaxoSmithKline Research and Development, Research Triangle Park, North Carolina, United States of America
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Teekakirikul P, Padera RF, Seidman JG, Seidman CE. Hypertrophic cardiomyopathy: translating cellular cross talk into therapeutics. ACTA ACUST UNITED AC 2013; 199:417-21. [PMID: 23109667 PMCID: PMC3483129 DOI: 10.1083/jcb.201207033] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is a common inherited heart disease with serious adverse outcomes, including heart failure, arrhythmias, and sudden cardiac death. The discovery that mutations in sarcomere protein genes cause HCM has enabled the development of mouse models that recapitulate clinical manifestations of disease. Studies in these models have provided unexpected insights into the biophysical and biochemical properties of mutated contractile proteins and may help to improve clinical diagnosis and management of patients with HCM.
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