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Schwoerer AP, Biermann D, Ehmke H. Ventricular unloading causes prolongation of the QT interval and induces ventricular arrhythmias in rat hearts. Front Physiol 2024; 15:1346093. [PMID: 39022307 PMCID: PMC11251997 DOI: 10.3389/fphys.2024.1346093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 06/10/2024] [Indexed: 07/20/2024] Open
Abstract
Introduction Ventricular unloading during prolonged bed rest, mechanical circulatory support or microgravity has repeatedly been linked to potentially life-threatening arrhythmias. It is unresolved, whether this arrhythmic phenotype is caused by the reduction in cardiac workload or rather by underlying diseases or external stimuli. We hypothesized that the reduction in cardiac workload alone is sufficient to impair ventricular repolarization and to induce arrhythmias in hearts. Methods Rat hearts were unloaded using the heterotopic heart transplantation. The ECG of unloaded and of control hearts were telemetrically recorded over 56 days resulting in >5 × 106 cardiac cycles in each heart. Long-term electrical remodeling was analyzed using a novel semi-automatic arrhythmia detection algorithm. Results 56 days of unloading reduced left ventricular weight by approximately 50%. While unloading did not affect average HRs, it markedly prolonged the QT interval by approximately 66% and induced a median tenfold increase in the incidence of ventricular arrhythmias in comparison to control hearts. Conclusion The current study provides direct evidence that the previously reported hypertrophic phenotype of repolarization during cardiac unloading translates into an impaired ventricular repolarization and ventricular arrhythmias in vivo. This supports the concept that the reduction in cardiac workload is a causal driver of the development of arrhythmias during ventricular unloading.
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Affiliation(s)
- Alexander Peter Schwoerer
- Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Daniel Biermann
- DZHK (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
- Department of Congenital and Pediatric Heart Surgery, Children’s Heart Clinic, University Heart and Vascular Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Heimo Ehmke
- Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
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2
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Ibrahim M, Acker MA, Szeto W, Gutsche J, Williams M, Atluri P, Woods M, Richards T, Gardner TJ, McGarvey J, Epler M, Wald J, Rame E, Birati E, Bermudez C. Proposal for a trial of early left ventricular venting during venoarterial extracorporeal membrane oxygenation for cardiogenic shock. JTCVS OPEN 2021; 8:393-400. [PMID: 36004109 PMCID: PMC9390694 DOI: 10.1016/j.xjon.2021.07.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 07/26/2021] [Indexed: 11/07/2022]
Abstract
Objective Patients with profound cardiogenic shock may require venoarterial (VA) extracorporeal membrane oxygenation (ECMO) for circulatory support most commonly via the femoral vessels. The rate of cardiac recovery in this population remains low, possibly because peripheral VA-ECMO increases ventricular afterload. Whether direct ventricular unloading in peripheral VA-ECMO enhances cardiac recovery is unknown, but is being more frequently utilized. A randomized trial is warranted to evaluate the clinical effectiveness of percutaneous left ventricle venting to enhance cardiac recovery in the setting of VA-ECMO. Methods We describe the rationale, design, and initial testing of a randomized controlled trial of VA-ECMO with and without percutaneous left ventricle venting using a percutaneous micro-axial ventricular assist device. Results This is an ongoing prospective randomized controlled trial in adult patients with primary cardiac failure presenting in cardiogenic shock requiring peripheral VA-ECMO, designed to test the safety and effectiveness of percutaneous left ventricle venting in improving the rate of cardiac recovery. Conclusions The results of this nonindustry-sponsored trial will provide critical information on whether left ventricle unloading in peripheral VA-ECMO is safe and effective.
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3
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Function and regulation of phosphatase 1 in healthy and diseased heart. Cell Signal 2021; 90:110203. [PMID: 34822978 DOI: 10.1016/j.cellsig.2021.110203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 11/12/2021] [Accepted: 11/18/2021] [Indexed: 12/12/2022]
Abstract
Reversible phosphorylation of ion channels and calcium-handling proteins provides precise post-translational regulation of cardiac excitation and contractility. Serine/threonine phosphatases govern dephosphorylation of the majority of cardiac proteins. Accordingly, dysfunction of this regulation contributes to the development and progression of heart failure and atrial fibrillation. On the molecular level, these changes include alterations in the expression level and phosphorylation status of Ca2+ handling and excitation-contraction coupling proteins provoked by dysregulation of phosphatases. The serine/threonine protein phosphatase PP1 is one a major player in the regulation of cardiac excitation-contraction coupling. PP1 essentially impacts on cardiac physiology and pathophysiology via interactions with the cardiac ion channels Cav1.2, NKA, NCX and KCNQ1, sarcoplasmic reticulum-bound Ca2+ handling proteins such as RyR2, SERCA and PLB as well as the contractile proteins MLC2, TnI and MyBP-C. PP1 itself but also PP1-regulatory proteins like inhibitor-1, inhibitor-2 and heat-shock protein 20 are dysregulated in cardiac disease. Therefore, they represent interesting targets to gain more insights in heart pathophysiology and to identify new treatment strategies for patients with heart failure or atrial fibrillation. We describe the genetic and holoenzymatic structure of PP1 and review its role in the heart and cardiac disease. Finally, we highlight the importance of the PP1 regulatory proteins for disease manifestation, provide an overview of genetic models to study the role of PP1 for the development of heart failure and atrial fibrillation and discuss possibilities of pharmacological interventions.
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Abstract
The field of cAMP signaling is witnessing exciting developments with the recognition that cAMP is compartmentalized and that spatial regulation of cAMP is critical for faithful signal coding. This realization has changed our understanding of cAMP signaling from a model in which cAMP connects a receptor at the plasma membrane to an intracellular effector in a linear pathway to a model in which cAMP signals propagate within a complex network of alternative branches and the specific functional outcome strictly depends on local regulation of cAMP levels and on selective activation of a limited number of branches within the network. In this review, we cover some of the early studies and summarize more recent evidence supporting the model of compartmentalized cAMP signaling, and we discuss how this knowledge is starting to provide original mechanistic insight into cell physiology and a novel framework for the identification of disease mechanisms that potentially opens new avenues for therapeutic interventions.
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Affiliation(s)
- Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna Zerio
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Miguel J Lobo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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5
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Westhofen S, Jelinek M, Dreher L, Biermann D, Martin J, Vitzhum H, Reichenspurner H, Ehmke H, Schwoerer AP. The heterotopic heart transplantation in mice as a small animal model to study mechanical unloading - Establishment of the procedure, perioperative management and postoperative scoring. PLoS One 2019; 14:e0214513. [PMID: 30978185 PMCID: PMC6461225 DOI: 10.1371/journal.pone.0214513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 03/14/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Unloading of failing hearts by left ventricular assist devices induces an extensive cardiac remodeling which may lead to a reversal of the initial phenotype-or to its deterioration. The mechanisms underlying these processes are unclear. HYPOTHESIS Heterotopic heart transplantion (hHTX) is an accepted model for the study of mechanical unloading in rodents. The wide variety of genetically modified strains in mice provides an unique opportunity to examine remodeling pathways. However, the procedure is technically demanding and has not been extensively used in this area. To support investigators adopting this method, we present our experience establishing the abdominal hHTX in mice and describe refinements to the technique. METHODS In this model, the transplanted heart is vascularised but implanted in series, and therefore does not contribute to systemic circulation and results in a complete mechanical unloading of the donor heart. Training followed a systematic program using a combination of literature, video tutorials, cadaveric training, direct observation and training in live animals. RESULTS Successful transplantation was defined as a recipient surviving > 24 hours with a palpable, beating apex in the transplanted heart and was achieved after 20 transplants in live animals. A success rate of 90% was reached after 60 transplants. Operative time was shown to decrease in correlation with increasing number of procedures from 200 minutes to 45 minutes after 60 operations. Cold/warm ischemia time improved from 45/100 to 10/20 minutes. Key factors for success and trouble shootings were identified. CONCLUSION Abdominal hHTX in the mouse may enable future examination of specific pathways in unloading induced myocardial remodeling. Establishment of the technique, however, is challenging. Structured training programs utilising a variety of training methods can help to expedite the process. Postoperative management, including daily scoring increases animal wellbeing and helps to predict survival.
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Affiliation(s)
- Sumi Westhofen
- Department of Cardiovascular Surgery, University Heart Center, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
- * E-mail:
| | - Marisa Jelinek
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
- Department of Cellular and Integrative Physiology, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Leonie Dreher
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
- Department of Cellular and Integrative Physiology, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Daniel Biermann
- Department of Cardiovascular Surgery, University Heart Center, Hamburg, Germany
| | - Jack Martin
- Department of Surgery, Addenbrookes Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Helga Vitzhum
- Department of Cellular and Integrative Physiology, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Hermann Reichenspurner
- Department of Cardiovascular Surgery, University Heart Center, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Heimo Ehmke
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
- Department of Cellular and Integrative Physiology, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Alexander Peter Schwoerer
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
- Department of Cellular and Integrative Physiology, University Medical Center Hamburg Eppendorf, Hamburg, Germany
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6
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Schaefer A, Schneeberger Y, Schulz S, Krasemann S, Werner T, Piasecki A, Höppner G, Müller C, Morhenn K, Lorenz K, Wieczorek D, Schwoerer AP, Eschenhagen T, Ehmke H, Reichenspurner H, Stenzig J, Cuello F. Analysis of fibrosis in control or pressure overloaded rat hearts after mechanical unloading by heterotopic heart transplantation. Sci Rep 2019; 9:5710. [PMID: 30952943 PMCID: PMC6451012 DOI: 10.1038/s41598-019-42263-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 01/22/2019] [Indexed: 02/03/2023] Open
Abstract
Mechanical unloading (MU) by implantation of left ventricular assist devices (LVAD) has become clinical routine. This procedure has been shown to reverse cardiac pathological remodeling, with the underlying molecular mechanisms incompletely understood. Most studies thus far were performed in non-standardized human specimens or MU of healthy animal hearts. Our study investigates cardiac remodeling processes in sham-operated healthy rat hearts and in hearts subjected to standardized pathological pressure overload by transverse aortic constriction (TAC) prior to MU by heterotopic heart transplantation (hHTx/MU). Rats underwent sham or TAC surgery. Disease progression was monitored by echocardiography prior to MU by hHTx/MU. Hearts after TAC or TAC combined with hHTx/MU were removed and analyzed by histology, western immunoblot and gene expression analysis. TAC surgery resulted in cardiac hypertrophy and impaired cardiac function. TAC hearts revealed significantly increased cardiac myocyte diameter and mild fibrosis. Expression of hypertrophy associated genes after TAC was higher compared to hearts after hHTx/MU. While cardiac myocyte cell diameter regressed to the level of sham-operated controls in all hearts subjected to hHTx/MU, fibrotic remodeling was significantly exacerbated. Transcription of pro-fibrotic and apoptosis-related genes was markedly augmented in all hearts after hHTx/MU. Sarcomeric proteins involved in excitation-contraction coupling displayed significantly lower phosphorylation levels after TAC and significantly reduced total protein levels after hHTx/MU. Development of myocardial fibrosis, cardiac myocyte atrophy and loss of sarcomeric proteins was observed in all hearts that underwent hHTX/MU regardless of the disease state. These results may help to explain the clinical experience with low rates of LVAD removal due to lack of myocardial recovery.
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Affiliation(s)
- Andreas Schaefer
- Department of Cardiovascular Surgery, University Heart Center Hamburg, Hamburg, Germany. .,DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany. .,Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Yvonne Schneeberger
- Department of Cardiovascular Surgery, University Heart Center Hamburg, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Steven Schulz
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susanne Krasemann
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tessa Werner
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Angelika Piasecki
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Grit Höppner
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Müller
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of General and Interventional Cardiology, University Heart Center, Hamburg, Germany
| | - Karoline Morhenn
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | - Alexander P Schwoerer
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Eschenhagen
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Heimo Ehmke
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hermann Reichenspurner
- Department of Cardiovascular Surgery, University Heart Center Hamburg, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Justus Stenzig
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Friederike Cuello
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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7
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Castillero E, Ali ZA, Akashi H, Giangreco N, Wang C, Stöhr EJ, Ji R, Zhang X, Kheysin N, Park JES, Hegde S, Patel S, Stein S, Cuenca C, Leung D, Homma S, Tatonetti NP, Topkara VK, Takeda K, Colombo PC, Naka Y, Sweeney HL, Schulze PC, George I. Structural and functional cardiac profile after prolonged duration of mechanical unloading: potential implications for myocardial recovery. Am J Physiol Heart Circ Physiol 2018; 315:H1463-H1476. [PMID: 30141986 PMCID: PMC6297806 DOI: 10.1152/ajpheart.00187.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/18/2018] [Accepted: 08/02/2018] [Indexed: 11/22/2022]
Abstract
Clinical and experimental studies have suggested that the duration of left ventricular assist device (LVAD) support may affect remodeling of the failing heart. We aimed to 1) characterize the changes in Ca2+/calmodulin-dependent protein kinase type-IIδ (CaMKIIδ), growth signaling, structural proteins, fibrosis, apoptosis, and gene expression before and after LVAD support and 2) assess whether the duration of support correlated with improvement or worsening of reverse remodeling. Left ventricular apex tissue and serum pairs were collected in patients with dilated cardiomyopathy ( n = 25, 23 men and 2 women) at LVAD implantation and after LVAD support at cardiac transplantation/LVAD explantation. Normal cardiac tissue was obtained from healthy hearts ( n = 4) and normal serum from age-matched control hearts ( n = 4). The duration of LVAD support ranged from 48 to 1,170 days (median duration: 270 days). LVAD support was associated with CaMKIIδ activation, increased nuclear myocyte enhancer factor 2, sustained histone deacetylase-4 phosphorylation, increased circulating and cardiac myostatin (MSTN) and MSTN signaling mediated by SMAD2, ongoing structural protein dysregulation and sustained fibrosis and apoptosis (all P < 0.05). Increased CaMKIIδ phosphorylation, nuclear myocyte enhancer factor 2, and cardiac MSTN significantly correlated with the duration of support. Phosphorylation of SMAD2 and apoptosis decreased with a shorter duration of LVAD support but increased with a longer duration of LVAD support. Further study is needed to define the optimal duration of LVAD support in patients with dilated cardiomyopathy. NEW & NOTEWORTHY A long duration of left ventricular assist device support may be detrimental for myocardial recovery, based on myocardial tissue experiments in patients with prolonged support showing significantly worsened activation of Ca2+/calmodulin-dependent protein kinase-IIδ, increased nuclear myocyte enhancer factor 2, increased myostatin and its signaling by SMAD2, and apoptosis as well as sustained histone deacetylase-4 phosphorylation, structural protein dysregulation, and fibrosis.
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Affiliation(s)
- Estibaliz Castillero
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Ziad A Ali
- Division of Cardiology, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Hirokazu Akashi
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Nicholas Giangreco
- Department of Biomedical Informatics, Systems Biology, Institute for Genomic Medicine, Data Science Institute, Columbia University , New York, New York
| | - Catherine Wang
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Eric J Stöhr
- Division of Cardiology, College of Physicians and Surgeons of Columbia University , New York, New York
- School of Sport and Health Sciences, Cardiff Metropolitan University , Cardiff , United Kingdom
| | - Ruping Ji
- Division of Cardiology, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Xiaokan Zhang
- Division of Cardiology, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Nathaniel Kheysin
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Joo-Eun S Park
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Sheetal Hegde
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Sanatkumar Patel
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Samantha Stein
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Carlos Cuenca
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Diana Leung
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Shunichi Homma
- Division of Cardiology, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Nicholas P Tatonetti
- Department of Biomedical Informatics, Systems Biology, Institute for Genomic Medicine, Data Science Institute, Columbia University , New York, New York
| | - Veli K Topkara
- Division of Cardiology, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Koji Takeda
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Paolo C Colombo
- Division of Cardiology, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Yoshifumi Naka
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
| | - H Lee Sweeney
- Department of Pharmacology, University of Florida , Gainesville, Florida
| | - P Christian Schulze
- Division of Cardiology, College of Physicians and Surgeons of Columbia University , New York, New York
| | - Isaac George
- Division of Cardiothoracic Surgery, College of Physicians and Surgeons of Columbia University , New York, New York
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8
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Chiang DY, Heck AJR, Dobrev D, Wehrens XHT. Regulating the regulator: Insights into the cardiac protein phosphatase 1 interactome. J Mol Cell Cardiol 2016; 101:165-172. [PMID: 27663175 PMCID: PMC5154861 DOI: 10.1016/j.yjmcc.2016.09.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/15/2016] [Accepted: 09/18/2016] [Indexed: 11/28/2022]
Abstract
Reversible phosphorylation of proteins is a delicate yet dynamic balancing act between kinases and phosphatases, the disturbance of which underlies numerous disease processes. While our understanding of protein kinases has grown tremendously over the past decades, relatively little is known regarding protein phosphatases. This may be because protein kinases are great in number and relatively specific in function, and thereby amenable to be studied in isolation, whereas protein phosphatases are much less abundant and more nonspecific in their function. To achieve subcellular localization and substrate specificity, phosphatases depend on partnering with a large number of regulatory subunits, protein scaffolds and/or other interactors. This added layer of complexity presents a significant barrier to their study, but holds the key to unexplored opportunities for novel pharmacologic intervention. In this review we focus on serine/threonine protein phosphatase type-1 (PP1), which plays an important role in cardiac physiology and pathophysiology. Although much work has been done to investigate the role of PP1 in cardiac diseases including atrial fibrillation and heart failure, most of these studies were limited to examining and manipulating the catalytic subunit(s) of PP1 without adequately considering the PP1 interactors, which give specificity to PP1's functions. To complement these studies, three unbiased methods have been developed and applied to the mapping of the PP1 interactome: bioinformatics approaches, yeast two-hybrid screens, and affinity-purification mass spectrometry. The application of these complementary methods has the potential to generate a detailed cardiac PP1 interactome, which is an important step in identifying novel and targeted pharmacological interventions.
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Affiliation(s)
- David Y Chiang
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands; Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Dobromir Dobrev
- Institute of Pharmacology, University Duisburg/Essen, Essen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA; Department of Medicine (Cardiology), Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics (Cardiology), Baylor College of Medicine, Houston, TX, USA.
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9
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A New Animal Model for Investigation of Mechanical Unloading in Hypertrophic and Failing Hearts: Combination of Transverse Aortic Constriction and Heterotopic Heart Transplantation. PLoS One 2016; 11:e0148259. [PMID: 26841021 PMCID: PMC4739720 DOI: 10.1371/journal.pone.0148259] [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: 10/05/2015] [Accepted: 01/15/2016] [Indexed: 11/29/2022] Open
Abstract
Objectives Previous small animal models for simulation of mechanical unloading are solely performed in healthy or infarcted hearts, not representing the pathophysiology of hypertrophic and dilated hearts emerging in heart failure patients. In this article, we present a new and economic small animal model to investigate mechanical unloading in hypertrophic and failing hearts: the combination of transverse aortic constriction (TAC) and heterotopic heart transplantation (hHTx) in rats. Methods To induce cardiac hypertrophy and failure in rat hearts, three-week old rats underwent TAC procedure. Three and six weeks after TAC, hHTx with hypertrophic and failing hearts in Lewis rats was performed to induce mechanical unloading. After 14 days of mechanical unloading animals were euthanatized and grafts were explanted for further investigations. Results 50 TAC procedures were performed with a survival of 92% (46/50). When compared to healthy rats left ventricular surface decreased to 5.8±1.0 mm² (vs. 9.6± 2.4 mm²) (p = 0.001) after three weeks with a fractional shortening (FS) of 23.7± 4.3% vs. 28.2± 1.5% (p = 0.01). Six weeks later, systolic function decreased to 17.1± 3.2% vs. 28.2± 1.5% (p = 0.0001) and left ventricular inner surface increased to 19.9±1.1 mm² (p = 0.0001). Intraoperative graft survival during hHTx was 80% with 46 performed procedures (37/46). All transplanted organs survived two weeks of mechanical unloading. Discussion Combination of TAC and hHTx in rats offers an economic and reproducible small animal model enabling serial examination of mechanical unloading in a truly hypertrophic and failing heart, representing the typical pressure overloaded and dilated LV, occurring in patients with moderate to severe heart failure.
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10
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Weber S, Meyer-Roxlau S, Wagner M, Dobrev D, El-Armouche A. Counteracting Protein Kinase Activity in the Heart: The Multiple Roles of Protein Phosphatases. Front Pharmacol 2015; 6:270. [PMID: 26617522 PMCID: PMC4643138 DOI: 10.3389/fphar.2015.00270] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/28/2015] [Indexed: 12/19/2022] Open
Abstract
Decades of cardiovascular research have shown that variable and flexible levels of protein phosphorylation are necessary to maintain cardiac function. A delicate balance between phosphorylated and dephosphorylated states of proteins is guaranteed by a complex interplay of protein kinases (PKs) and phosphatases. Serine/threonine phosphatases, in particular members of the protein phosphatase (PP) family govern dephosphorylation of the majority of these cardiac proteins. Recent findings have however shown that PPs do not only dephosphorylate previously phosphorylated proteins as a passive control mechanism but are capable to actively control PK activity via different direct and indirect signaling pathways. These control mechanisms can take place on (epi-)genetic, (post-)transcriptional, and (post-)translational levels. In addition PPs themselves are targets of a plethora of proteinaceous interaction partner regulating their endogenous activity, thus adding another level of complexity and feedback control toward this system. Finally, novel approaches are underway to achieve spatiotemporal pharmacologic control of PPs which in turn can be used to fine-tune misleaded PK activity in heart disease. Taken together, this review comprehensively summarizes the major aspects of PP-mediated PK regulation and discusses the subsequent consequences of deregulated PP activity for cardiovascular diseases in depth.
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Affiliation(s)
- Silvio Weber
- Department of Pharmacology and Toxicology, Dresden University of Technology , Dresden, Germany
| | - Stefanie Meyer-Roxlau
- Department of Pharmacology and Toxicology, Dresden University of Technology , Dresden, Germany
| | - Michael Wagner
- Department of Pharmacology and Toxicology, Dresden University of Technology , Dresden, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, Faculty of Medicine, West German Heart and Vascular Center , Essen, Germany
| | - Ali El-Armouche
- Department of Pharmacology and Toxicology, Dresden University of Technology , Dresden, Germany
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11
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Ahmad F, Shen W, Vandeput F, Szabo-Fresnais N, Krall J, Degerman E, Goetz F, Klussmann E, Movsesian M, Manganiello V. Regulation of sarcoplasmic reticulum Ca2+ ATPase 2 (SERCA2) activity by phosphodiesterase 3A (PDE3A) in human myocardium: phosphorylation-dependent interaction of PDE3A1 with SERCA2. J Biol Chem 2015; 290:6763-76. [PMID: 25593322 DOI: 10.1074/jbc.m115.638585] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclic nucleotide phosphodiesterase 3A (PDE3) regulates cAMP-mediated signaling in the heart, and PDE3 inhibitors augment contractility in patients with heart failure. Studies in mice showed that PDE3A, not PDE3B, is the subfamily responsible for these inotropic effects and that murine PDE3A1 associates with sarcoplasmic reticulum Ca(2+) ATPase 2 (SERCA2), phospholamban (PLB), and AKAP18 in a multiprotein signalosome in human sarcoplasmic reticulum (SR). Immunohistochemical staining demonstrated that PDE3A co-localizes in Z-bands of human cardiac myocytes with desmin, SERCA2, PLB, and AKAP18. In human SR fractions, cAMP increased PLB phosphorylation and SERCA2 activity; this was potentiated by PDE3 inhibition but not by PDE4 inhibition. During gel filtration chromatography of solubilized SR membranes, PDE3 activity was recovered in distinct high molecular weight (HMW) and low molecular weight (LMW) peaks. HMW peaks contained PDE3A1 and PDE3A2, whereas LMW peaks contained PDE3A1, PDE3A2, and PDE3A3. Western blotting showed that endogenous HMW PDE3A1 was the principal PKA-phosphorylated isoform. Phosphorylation of endogenous PDE3A by rPKAc increased cAMP-hydrolytic activity, correlated with shift of PDE3A from LMW to HMW peaks, and increased co-immunoprecipitation of SERCA2, cav3, PKA regulatory subunit (PKARII), PP2A, and AKAP18 with PDE3A. In experiments with recombinant proteins, phosphorylation of recombinant human PDE3A isoforms by recombinant PKA catalytic subunit increased co-immunoprecipitation with rSERCA2 and rat rAKAP18 (recombinant AKAP18). Deletion of the recombinant human PDE3A1/PDE3A2 N terminus blocked interactions with recombinant SERCA2. Serine-to-alanine substitutions identified Ser-292/Ser-293, a site unique to human PDE3A1, as the principal site regulating its interaction with SERCA2. These results indicate that phosphorylation of human PDE3A1 at a PKA site in its unique N-terminal extension promotes its incorporation into SERCA2/AKAP18 signalosomes, where it regulates a discrete cAMP pool that controls contractility by modulating phosphorylation-dependent protein-protein interactions, PLB phosphorylation, and SERCA2 activity.
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Affiliation(s)
- Faiyaz Ahmad
- From the Cardiovascular Pulmonary Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892,
| | - Weixing Shen
- From the Cardiovascular Pulmonary Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Fabrice Vandeput
- VA Salt Lake City Health Care System and University of Utah, Salt Lake City, Utah
| | | | - Judith Krall
- VA Salt Lake City Health Care System and University of Utah, Salt Lake City, Utah
| | - Eva Degerman
- Department of Experimental Medical Science, Division for Diabetes, Metabolism, and Endocrinology, Lund University, Lund, Sweden
| | - Frank Goetz
- Max Delbrueck Center for Molecular Medicine Berlin-Buch (MDC), 13125 Germany, and
| | - Enno Klussmann
- Max Delbrueck Center for Molecular Medicine Berlin-Buch (MDC), 13125 Germany, and DZHK, German Centre for Cardiovascular Research, 13347 Berlin, Germany
| | - Matthew Movsesian
- VA Salt Lake City Health Care System and University of Utah, Salt Lake City, Utah
| | - Vincent Manganiello
- From the Cardiovascular Pulmonary Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
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12
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Ramila KC, Jong CJ, Pastukh V, Ito T, Azuma J, Schaffer SW. Role of protein phosphorylation in excitation-contraction coupling in taurine deficient hearts. Am J Physiol Heart Circ Physiol 2014; 308:H232-9. [PMID: 25437920 DOI: 10.1152/ajpheart.00497.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Taurine is a beta-amino acid found in very high concentration in the heart. Depletion of these intracellular stores results in the development of cardiomyopathy, thought to be mediated by abnormal sarcoplasmic reticular (SR) Ca(2+) transport. There is also evidence that taurine directly alters the Ca(2+) sensitivity of myofibrillar proteins. Major regulators of SR Ca(2+) ATPase (SERCA2a) are the phosphorylation status of a regulatory protein, phospholamban, and SERCA2a expression, which are diminished in the failing heart. The failing heart also exhibits reductions in myofibrillar Ca(2+) sensitivity, a property regulated by the phosphorylation of the muscle protein, troponin I. Therefore, we tested the hypothesis that taurine deficiency leads to alterations in SR Ca(2+) ATPase activity related to reduced phospholamban phosphorylation and expression of SERCA2a. We found that a sequence of events, which included elevated protein phosphatase 1 activity, reduced autophosphorylation of CaMKII, and reduced phospholamban phosphorylation, supports the reduction in SR Ca(2+) ATPase activity. However, the reduction in SR Ca(2+) ATPase activity was not caused by reduced SERCA2a expression. Taurine transporter knockout (TauTKO) hearts also exhibited a rightward shift in the Ca(2+) dependence of the myofibrillar Ca(2+) ATPase, a property that is associated with an elevation in phosphorylated troponin I. The findings support the observation that taurine deficient hearts develop systolic and diastolic defects related to reduced SR Ca(2+) ATPase activity, a change mediated in part by reduced phospholamban phosphorylation.
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Affiliation(s)
- K C Ramila
- University of South Alabama, College of Medicine, Department of Pharmacology, Mobile, Alabama; and
| | - Chian Ju Jong
- University of South Alabama, College of Medicine, Department of Pharmacology, Mobile, Alabama; and
| | - Viktor Pastukh
- University of South Alabama, College of Medicine, Department of Pharmacology, Mobile, Alabama; and
| | - Takashi Ito
- Hyogo University of Health Sciences, School of Pharmacy, Department of Pharmacy, Kobe, Japan
| | - Junichi Azuma
- Hyogo University of Health Sciences, School of Pharmacy, Department of Pharmacy, Kobe, Japan
| | - Stephen W Schaffer
- University of South Alabama, College of Medicine, Department of Pharmacology, Mobile, Alabama; and
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13
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Manders E, Bogaard HJ, Handoko ML, van de Veerdonk MC, Keogh A, Westerhof N, Stienen GJM, Dos Remedios CG, Humbert M, Dorfmüller P, Fadel E, Guignabert C, van der Velden J, Vonk-Noordegraaf A, de Man FS, Ottenheijm CAC. Contractile dysfunction of left ventricular cardiomyocytes in patients with pulmonary arterial hypertension. J Am Coll Cardiol 2014; 64:28-37. [PMID: 24998125 DOI: 10.1016/j.jacc.2014.04.031] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/16/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND After lung transplantation, increased left ventricular (LV) filling can lead to LV failure, increasing the risk of post-operative complications and mortality. LV dysfunction in pulmonary arterial hypertension (PAH) is characterized by a reduced LV ejection fraction and impaired diastolic function. OBJECTIVES The pathophysiology of LV dysfunction in PAH is incompletely understood. This study sought to assess the contribution of atrophy and contractility of cardiomyocytes to LV dysfunction in PAH patients. METHODS LV function was assessed by cardiac magnetic resonance imaging. In addition, LV biopsies were obtained in 9 PAH patients and 10 donors. The cross-sectional area (CSA) and force-generating capacity of isolated single cardiomyocytes was investigated. RESULTS Magnetic resonance imaging analysis revealed a significant reduction in LV ejection fraction in PAH patients, indicating a reduction in LV contractility. The CSA of LV cardiomyocytes of PAH patients was significantly reduced (~30%), indicating LV cardiomyocyte atrophy. The maximal force-generating capacity, normalized to cardiomyocyte CSA, was significantly reduced (~25%). Also, a reduction in the number of available myosin-based cross-bridges was found to cause the contractile weakness of cardiomyocytes. This finding was supported by protein analyses, which showed an ~30% reduction in the myosin/actin ratio in cardiomyocytes from PAH patients. Finally, the phosphorylation level of sarcomeric proteins was reduced in PAH patients, which was accompanied by increased calcium sensitivity of force generation. CONCLUSIONS The contractile function and the CSA of LV cardiomyocytes is substantially reduced in PAH patients. We propose that these changes contribute to the reduced in vivo contractility of the LV in PAH patients.
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Affiliation(s)
- Emmy Manders
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands; Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Harm-Jan Bogaard
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands
| | - M Louis Handoko
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands; Cardiology Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Marielle C van de Veerdonk
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands
| | - Anne Keogh
- Heart Transplant Unit, St. Vincent's Hospital, Sydney, Australia
| | - Nico Westerhof
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands; Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Ger J M Stienen
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands; Department of Physics and Astronomy, VU University, Amsterdam, the Netherlands
| | | | - Marc Humbert
- University of Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, France; Assistance Publique-Hôpitaux de Paris, Service de Pneumologie, Département Hospitalo-Universitaire, Thorax Innovation (DHU TORINO), Hôpital Bicêtre, Le Kremlin-Bicêtre, France; Inserm U999, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LabEx LERMIT), Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France
| | - Peter Dorfmüller
- University of Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, France; Inserm U999, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LabEx LERMIT), Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France; Service d'Anatomie Pathologique, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France
| | - Elie Fadel
- University of Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, France; Inserm U999, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LabEx LERMIT), Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France; Service de Chirurgie Thoracique, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France
| | - Christophe Guignabert
- University of Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, France; Inserm U999, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LabEx LERMIT), Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France
| | - Jolanda van der Velden
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands; ICIN Netherlands Heart Institute, Utrecht, the Netherlands
| | - Anton Vonk-Noordegraaf
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands
| | - Frances S de Man
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands.
| | - Coen A C Ottenheijm
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands.
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14
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Zhao Y, Hu HY, Sun DR, Feng R, Sun XF, Guo F, Hao LY. Dynamic alterations in the CaV1.2/CaM/CaMKII signaling pathway in the left ventricular myocardium of ischemic rat hearts. DNA Cell Biol 2014; 33:282-90. [PMID: 24548334 DOI: 10.1089/dna.2013.2231] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Cardiac L-type calcium channel (CaV1.2), calmodulin (CaM), and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) form the CaV1.2/CaM/CaMKII signaling pathway, which plays an important role in maintaining intracellular Ca(2+) homeostasis. The roles of CaM and CaMKII in the regulation of CaV1.2 in Ca(2+)-dependent inactivation and facilitation have been reported; however, alterations in this signaling pathway in the heart after myocardial ischemia (MI) had not been well characterized. In this study, we investigated the dynamic changes in CaV1.2, CaM, and CaMKII mRNA and protein expression levels in the left ventricles of the heart following MI in rats. The MI model was induced by ligating the left anterior descending coronary artery; the rats were divided into the following five groups: the 6 h post-MI group (MI-6h), 24 h post-MI group (MI-24h), 1 week post-MI group (MI-1w), 2 weeks post-MI group (MI-2w), and the sham group. The mRNA levels were measured by quantitative real-time polymerase chain reaction and the protein expression was determined by western blotting and immunohistochemistry. There were no observable differences in the CaV1.2 mRNA and protein levels at the early stages of MI, but these levels decreased at MI-2w. Both the mRNA and protein levels of CaM increased at MI-6h, peaked at MI-24h, and then reduced to normal levels at MI-2w. CaMKII mRNA and protein levels decreased at MI-6h and reached their lowest level at MI-24h. Taken together, these data demonstrate that there are dynamic changes in the CaV1.2/CaM/CaMKII signaling pathway following MI injuries, which suggests that different therapeutic regimens should be used at different time points after MI injuries.
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Affiliation(s)
- Yan Zhao
- 1 Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University , Shenyang, People's Republic of China
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15
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Schwoerer AP, Neef S, Broichhausen I, Jacubeit J, Tiburcy M, Wagner M, Biermann D, Didié M, Vettel C, Maier LS, Zimmermann WH, Carrier L, Eschenhagen T, Volk T, El-Armouche A, Ehmke H. Enhanced Ca²+ influx through cardiac L-type Ca²+ channels maintains the systolic Ca²+ transient in early cardiac atrophy induced by mechanical unloading. Pflugers Arch 2013; 465:1763-73. [PMID: 23842739 PMCID: PMC3898408 DOI: 10.1007/s00424-013-1316-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 06/13/2013] [Accepted: 06/18/2013] [Indexed: 11/04/2022]
Abstract
Cardiac atrophy as a consequence of mechanical unloading develops following exposure to microgravity or prolonged bed rest. It also plays a central role in the reverse remodelling induced by left ventricular unloading in patients with heart failure. Surprisingly, the intracellular Ca2+ transients which are pivotal to electromechanical coupling and to cardiac plasticity were repeatedly found to remain unaffected in early cardiac atrophy. To elucidate the mechanisms underlying the preservation of the Ca2+ transients, we investigated Ca2+ cycling in cardiomyocytes from mechanically unloaded (heterotopic abdominal heart transplantation) and control (orthotopic) hearts in syngeneic Lewis rats. Following 2 weeks of unloading, sarcoplasmic reticulum (SR) Ca2+ content was reduced by ~55 %. Atrophic cardiac myocytes also showed a much lower frequency of spontaneous diastolic Ca2+ sparks and a diminished systolic Ca2+ release, even though the expression of ryanodine receptors was increased by ~30 %. In contrast, current clamp recordings revealed prolonged action potentials in endocardial as well as epicardial myocytes which were associated with a two to fourfold higher sarcolemmal Ca2+ influx under action potential clamp. In addition, Cav1.2 subunits which form the pore of L-type Ca2+ channels (LTCC) were upregulated in atrophic myocardium. These data suggest that in early cardiac atrophy induced by mechanical unloading, an augmented sarcolemmal Ca2+ influx through LTCC fully compensates for a reduced systolic SR Ca2+ release to preserve the Ca2+ transient. This interplay involves an electrophysiological remodelling as well as changes in the expression of cardiac ion channels.
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Affiliation(s)
- A. P. Schwoerer
- Department of Cellular and Integrative Physiology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Martinistr 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research)—Hamburg/Kiel/Luebeck, Hamburg, Germany
| | - S. Neef
- Department of Cardiology, Heart Research Center, Georg-August-University Goettingen, Goettingen, Germany
| | - I. Broichhausen
- Department of Cellular and Integrative Physiology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Martinistr 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research)—Hamburg/Kiel/Luebeck, Hamburg, Germany
| | - J. Jacubeit
- Department of Cellular and Integrative Physiology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Martinistr 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research)—Hamburg/Kiel/Luebeck, Hamburg, Germany
| | - M. Tiburcy
- Institute of Pharmacology, Heart Research Center, Georg-August-University Goettingen, Goettingen, Germany
- DZHK (German Centre for Cardiovascular Research)—Goettingen, Goettingen, Germany
| | - M. Wagner
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - D. Biermann
- Department of Cardiovascular Surgery, Center for Cardiology and Cardiovascular Surgery, University Heart Center, University Medical Center Hamburg-Eppendorf, Martinistr 52, 20246 Hamburg, Germany
| | - M. Didié
- Department of Cardiology, Heart Research Center, Georg-August-University Goettingen, Goettingen, Germany
- Institute of Pharmacology, Heart Research Center, Georg-August-University Goettingen, Goettingen, Germany
- DZHK (German Centre for Cardiovascular Research)—Goettingen, Goettingen, Germany
| | - C. Vettel
- Institute of Pharmacology, Heart Research Center, Georg-August-University Goettingen, Goettingen, Germany
- DZHK (German Centre for Cardiovascular Research)—Goettingen, Goettingen, Germany
| | - L. S. Maier
- Department of Cardiology, Heart Research Center, Georg-August-University Goettingen, Goettingen, Germany
- DZHK (German Centre for Cardiovascular Research)—Goettingen, Goettingen, Germany
| | - W. H. Zimmermann
- Institute of Pharmacology, Heart Research Center, Georg-August-University Goettingen, Goettingen, Germany
- DZHK (German Centre for Cardiovascular Research)—Goettingen, Goettingen, Germany
| | - L. Carrier
- DZHK (German Centre for Cardiovascular Research)—Hamburg/Kiel/Luebeck, Hamburg, Germany
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Martinistr 52, 20246 Hamburg, Germany
- Inserm, U974; CNRS, UMR7215; UPMC UM76, Institut de Myologie, Paris, 75013 France
| | - T. Eschenhagen
- DZHK (German Centre for Cardiovascular Research)—Hamburg/Kiel/Luebeck, Hamburg, Germany
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Martinistr 52, 20246 Hamburg, Germany
| | - T. Volk
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - A. El-Armouche
- Institute of Pharmacology, Heart Research Center, Georg-August-University Goettingen, Goettingen, Germany
- DZHK (German Centre for Cardiovascular Research)—Goettingen, Goettingen, Germany
| | - H. Ehmke
- Department of Cellular and Integrative Physiology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Martinistr 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research)—Hamburg/Kiel/Luebeck, Hamburg, Germany
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16
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Didié M, Biermann D, Buchert R, Hess A, Wittköpper K, Christalla P, Döker S, Jebran F, Schöndube F, Reichenspurner H, El-Armouche A, Zimmermann WH. Preservation of left ventricular function and morphology in volume-loaded versus volume-unloaded heterotopic heart transplants. Am J Physiol Heart Circ Physiol 2013; 305:H533-41. [PMID: 23771692 DOI: 10.1152/ajpheart.00218.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Total mechanical unloading of the heart in classical models of heterotopic heart transplantation leads to cardiac atrophy and functional deterioration. In contrast, partial unloading of failing human hearts with left ventricular (LV) assist devices (LVADs) can in some patients ameliorate heart failure symptoms. Here we tested in heterotopic rat heart transplant models whether partial volume-loading (VL; anastomoses: aorta of donor to aorta of recipient, pulmonary artery of donor to left atrium of donor, superior vena cava of donor to inferior vena cava of recipient; n = 27) is superior to the classical model of myocardial unloading (UL; anastomoses: aorta of donor to aorta of recipient, pulmonary artery of donor to inferior vena cava of recipient; n = 14) with respect to preservation of ventricular morphology and function. Echocardiography, magnetic resonance imaging, and LV-pressure-volume catheter revealed attenuated myocardial atrophy with ~30% higher LV weight and better systolic contractile function in VL compared with UL (fractional area shortening, 34% vs. 18%; maximal change in pressure over time, 2,986 ± 252 vs. 2,032 ± 193 mmHg/s). Interestingly, no differences in fibrosis (Picrosirus red staining) or glucose metabolism (2-[18F]-fluoro-2-deoxy-D-glucose-PET) between VL and UL were observed. We conclude that the rat model of partial VL attenuates atrophic remodelling and shows superior morphological as well as functional preservation, and thus should be considered more widely as a research model.
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Affiliation(s)
- Michael Didié
- Institute of Pharmacology, University Medical Center Göttingen and Deutsches Zentrum für Herz-Kreislauf-Forschung, partner site Göttingen, Germany
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17
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Fan XJ, Yu H, Ren J. Homeostasis and compensatory homeostasis: bridging Western medicine and traditional chinese medicine. Curr Cardiol Rev 2012; 7:43-6. [PMID: 22294974 PMCID: PMC3131715 DOI: 10.2174/157340311795677671] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/29/2010] [Accepted: 12/07/2010] [Indexed: 11/22/2022] Open
Abstract
Compensation is a self-protective mechanism in diseases, which may lead to a unique form of homeostasis deviates from that in physiological conditions. The kind of compensatory homeostasis can be embodied as various degrees accompanying disease progression (denoted as compensatory degree). Compensatory homeostasis provides a window for the transition from disease to healthy state. The causes of compensatory homeostasis themselves may be identified as targets for effective measures to eliminate compensation. Compensatory homeostasis embodies significantly mostly in the developing process of chronic diseases, which may help to explain in theory why intensive therapeutic strategies led to unexpected outcome in clinical practice. In addition, a large body of clinical evidence has valued traditional Chinese medicine (TCM), which is based on shifting compensatory homeostasis to the overall human body homeostasis, complementary to Western medicine in the management of chronic disease. In this review, we will briefly summarize the concept of compensation and attempt to bridge Western and traditional Chinese medicine through homeostasis and compensatory homeostasis based on an ample of evidence obtained from both disciplines
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Affiliation(s)
- Xiu-Juan Fan
- 1. China Nepstar Chain Drugstore Ltd., Hangzhou 310003 Zhejiang, China; 2. Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071, USA
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18
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Ambardekar AV, Buttrick PM. Reverse remodeling with left ventricular assist devices: a review of clinical, cellular, and molecular effects. Circ Heart Fail 2011; 4:224-33. [PMID: 21406678 DOI: 10.1161/circheartfailure.110.959684] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Amrut V Ambardekar
- Division of Cardiology, University of Colorado Denver, Aurora, CO 80045, USA.
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19
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Wittköpper K, Dobrev D, Eschenhagen T, El-Armouche A. Phosphatase-1 inhibitor-1 in physiological and pathological β-adrenoceptor signalling. Cardiovasc Res 2011; 91:392-401. [PMID: 21354993 DOI: 10.1093/cvr/cvr058] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Control of protein phosphorylation-dephosphorylation events occurs through regulation of protein kinases and phosphatases. Phosphatase type 1 (PP-1) provides the main activity of serine/threonine protein phosphatases in the heart. Inhibitor-1 (I-1) was the first endogenous molecule found to inhibit PP-1 specifically. Notably, I-1 is activated by cAMP-dependent protein kinase A (PKA), and the subsequent prevention of target dephosphorylation by PP-1 provides distal amplification of β-adrenoceptor (β-AR) signalling. I-1 was found to be down-regulated and hypo-phosphorylated in human and experimental heart failure but hyperactive in human atrial fibrillation, implicating I-1 in the pathogenesis of heart failure and arrhythmias. Consequently, the therapeutic potential of I-1 in heart failure and arrhythmias has recently been addressed by the generation and analysis of several I-1 genetic mouse models. This review summarizes and discusses these data, highlights partially controversial issues on whether I-1 should be therapeutically reinforced or inhibited and suggests future directions to better understand the functional role of I-1 in physiological and pathological β-AR signalling.
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Affiliation(s)
- Katrin Wittköpper
- Department of Pharmacology, University Medical Center Göttingen, Georg August University Göttingen, Göttingen, Germany
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20
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El-Armouche A, Schwoerer AP, Neuber C, Emmons J, Biermann D, Christalla T, Grundhoff A, Eschenhagen T, Zimmermann WH, Ehmke H. Common microRNA signatures in cardiac hypertrophic and atrophic remodeling induced by changes in hemodynamic load. PLoS One 2010; 5:e14263. [PMID: 21151612 PMCID: PMC3000324 DOI: 10.1371/journal.pone.0014263] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 11/16/2010] [Indexed: 11/19/2022] Open
Abstract
Background Mechanical overload leads to cardiac hypertrophy and mechanical unloading to cardiac atrophy. Both conditions produce similar transcriptional changes including a re-expression of fetal genes, despite obvious differences in phenotype. MicroRNAs (miRNAs) are discussed as superordinate regulators of global gene networks acting mainly at the translational level. Here, we hypothesized that defined sets of miRNAs may determine the direction of cardiomyocyte plasticity responses. Methodology/Principal Findings We employed ascending aortic stenosis (AS) and heterotopic heart transplantation (HTX) in syngenic Lewis rats to induce mechanical overloading and unloading, respectively. Heart weight was 26±3% higher in AS (n = 7) and 33±2% lower in HTX (n = 7) as compared to sham-operated (n = 6) and healthy controls (n = 7). Small RNAs were enriched from the left ventricles and subjected to quantitative stem-loop specific RT-PCR targeting a panel of 351 miRNAs. In total, 153 miRNAs could be unambiguously detected. Out of 72 miRNAs previously implicated in the cardiovascular system, 40 miRNAs were regulated in AS and/or HTX. Overall, HTX displayed a slightly broader activation pattern for moderately regulated miRNAs. Surprisingly, however, the regulation of individual miRNA expression was strikingly similar in direction and amplitude in AS and HTX with no miRNA being regulated in opposite direction. In contrast, fetal hearts from Lewis rats at embryonic day 18 exhibited an entirely different miRNA expression pattern. Conclusions Taken together, our findings demonstrate that opposite changes in cardiac workload induce a common miRNA expression pattern which is markedly different from the fetal miRNA expression pattern. The direction of postnatal adaptive cardiac growth does, therefore, not appear to be determined at the level of single miRNAs or a specific set of miRNAs. Moreover, miRNAs themselves are not reprogrammed to a fetal program in response to changes in hemodynamic load.
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Affiliation(s)
- Ali El-Armouche
- Department of Pharmacology, University Medical Center Goettingen (UMG), Goettingen, Germany
- Department of Experimental and Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail: (AE-A); (APS)
| | - Alexander Peter Schwoerer
- Department of Vegetative Physiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail: (AE-A); (APS)
| | - Christiane Neuber
- Department of Experimental and Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Julius Emmons
- Department of Pharmacology, University Medical Center Goettingen (UMG), Goettingen, Germany
| | - Daniel Biermann
- Department of Experimental and Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Christalla
- Heinrich-Pette-Institute for Experimental Virology and Immunology, Hamburg, Germany
| | - Adam Grundhoff
- Heinrich-Pette-Institute for Experimental Virology and Immunology, Hamburg, Germany
| | - Thomas Eschenhagen
- Department of Experimental and Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Wolfram Hubertus Zimmermann
- Department of Pharmacology, University Medical Center Goettingen (UMG), Goettingen, Germany
- Department of Experimental and Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Heimo Ehmke
- Department of Vegetative Physiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Rudolph V, Andrié RP, Rudolph TK, Friedrichs K, Klinke A, Hirsch-Hoffmann B, Schwoerer AP, Lau D, Fu X, Klingel K, Sydow K, Didié M, Seniuk A, von Leitner EC, Szoecs K, Schrickel JW, Treede H, Wenzel U, Lewalter T, Nickenig G, Zimmermann WH, Meinertz T, Böger RH, Reichenspurner H, Freeman BA, Eschenhagen T, Ehmke H, Hazen SL, Willems S, Baldus S. Myeloperoxidase acts as a profibrotic mediator of atrial fibrillation. Nat Med 2010; 16:470-4. [PMID: 20305660 DOI: 10.1038/nm.2124] [Citation(s) in RCA: 252] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Accepted: 02/22/2010] [Indexed: 01/19/2023]
Abstract
Observational clinical and ex vivo studies have established a strong association between atrial fibrillation and inflammation. However, whether inflammation is the cause or the consequence of atrial fibrillation and which specific inflammatory mediators may increase the atria's susceptibility to fibrillation remain elusive. Here we provide experimental and clinical evidence for the mechanistic involvement of myeloperoxidase (MPO), a heme enzyme abundantly expressed by neutrophils, in the pathophysiology of atrial fibrillation. MPO-deficient mice pretreated with angiotensin II (AngII) to provoke leukocyte activation showed lower atrial tissue abundance of the MPO product 3-chlorotyrosine, reduced activity of matrix metalloproteinases and blunted atrial fibrosis as compared to wild-type mice. Upon right atrial electrophysiological stimulation, MPO-deficient mice were protected from atrial fibrillation, which was reversed when MPO was restored. Humans with atrial fibrillation had higher plasma concentrations of MPO and a larger MPO burden in right atrial tissue as compared to individuals devoid of atrial fibrillation. In the atria, MPO colocalized with markedly increased formation of 3-chlorotyrosine. Our data demonstrate that MPO is a crucial prerequisite for structural remodeling of the myocardium, leading to an increased vulnerability to atrial fibrillation.
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Affiliation(s)
- Volker Rudolph
- 1Department of General and Interventional Cardiology and Cardiovascular Research Center, University Heart Center, Hamburg, Germany
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22
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Messer AE, Gallon CE, McKenna WJ, Dos Remedios CG, Marston SB. The use of phosphate-affinity SDS-PAGE to measure the cardiac troponin I phosphorylation site distribution in human heart muscle. Proteomics Clin Appl 2009; 3:1371-82. [PMID: 21136957 DOI: 10.1002/prca.200900071] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 08/21/2009] [Accepted: 08/22/2009] [Indexed: 11/10/2022]
Abstract
We have used phosphate affinity SDS-PAGE to separate the phosphorylated species of cardiac troponin I (cTnI). To test the method we phosphorylated pure cTnI with protein kinase A catalytic subunit and observed up to six bands corresponding to 0, 1P, 2P, 3P, 4P and 5P phospho-species. We examined the phospho-species of cTnI in human heart myofibrillar extracts by phosphate affinity SDS-PAGE and Western blotting with a non-specific troponin I (TnI) antibody. In donor heart samples the bis-phosphorylated species of cTnI predominated and no more highly phosphorylated species were not detectable (0P was 10.3±1.9%, 1P, 17.5±3.5%, 2P, 72.2±4.7%, 11 samples). Total phosphorylation was 1.62±0.06 molsPi/mol TnI. In myofibrils from end-stage failing hearts, the unphosphorylated cTnI species predominated (0P was 78.5±1.8%, 1P, 17.5±1.9%, 2P, 4.0±0.7%, total phosphorylation 0.26±0.02 molsPi/mol TnI, five samples). Muscle from patients with hypertrophic obstructive cardiomyopathy was also largely unphosphorylated (0P was 76.6±3.1%, 1P, 17.5±2.7%, 2P, 5.9±0.8%, total phosphorylation 0.29±0.04 molsPi/mol TnI, 19 samples). Using a range of phospho-specific antibodies we demonstrated that 3/4 of the bis-phosphorylated band of donor heart cTnI is phosphorylated at Ser22 and Ser23 in approximately equal amounts and that phosphorylation of Ser43 and Thr142 was not detected.
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Affiliation(s)
- Andrew E Messer
- National Heart and Lung Institute, Imperial College London, London, UK.
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23
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Berzingi C, Chen F, Finkel MS. P38 MAP Kinase Inhibitor Prevents Diastolic Dysfunction in Rats Following HIV gp120 Injection In vivo. Cardiovasc Toxicol 2009; 9:142-50. [DOI: 10.1007/s12012-009-9047-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Accepted: 07/15/2009] [Indexed: 01/15/2023]
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