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Kampourakis T, Ponnam S, Campbell KS, Wellette-Hunsucker A, Koch D. Cardiac myosin binding protein-C phosphorylation as a function of multiple protein kinase and phosphatase activities. Nat Commun 2024; 15:5111. [PMID: 38877002 PMCID: PMC11178824 DOI: 10.1038/s41467-024-49408-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/05/2024] [Indexed: 06/16/2024] Open
Abstract
Phosphorylation of cardiac myosin binding protein-C (cMyBP-C) is a determinant of cardiac myofilament function. Although cMyBP-C phosphorylation by various protein kinases has been extensively studied, the influence of protein phosphatases on cMyBP-C's multiple phosphorylation sites has remained largely obscure. Here we provide a detailed biochemical characterization of cMyBP-C dephosphorylation by protein phosphatases 1 and 2 A (PP1 and PP2A), and develop an integrated kinetic model for cMyBP-C phosphorylation using data for both PP1, PP2A and various protein kinases known to phosphorylate cMyBP-C. We find strong site-specificity and a hierarchical mechanism for both phosphatases, proceeding in the opposite direction of sequential phosphorylation by potein kinase A. The model is consistent with published data from human patients and predicts complex non-linear cMyBP-C phosphorylation patterns that are validated experimentally. Our results suggest non-redundant roles for PP1 and PP2A under both physiological and heart failure conditions, and emphasize the importance of phosphatases for cMyBP-C regulation.
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Affiliation(s)
- Thomas Kampourakis
- Randall Centre for Cell and Molecular Biophysics; and British Heart Foundation Centre of Research Excellence, King's College London, London, SE1 1UL, United Kingdom
| | - Saraswathi Ponnam
- Randall Centre for Cell and Molecular Biophysics; and British Heart Foundation Centre of Research Excellence, King's College London, London, SE1 1UL, United Kingdom
| | - Kenneth S Campbell
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, USA
| | | | - Daniel Koch
- Max Planck Institute for Neurobiology of Behavior-caesar, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.
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2
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Moen JM, Morrell CH, Matt MG, Ahmet I, Tagirova S, Davoodi M, Petr M, Charles S, de Cabo R, Yaniv Y, Lakatta EG. Emergence of heartbeat frailty in advanced age I: perspectives from life-long EKG recordings in adult mice. GeroScience 2022; 44:2801-2830. [PMID: 35759167 PMCID: PMC9768068 DOI: 10.1007/s11357-022-00605-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 06/06/2022] [Indexed: 01/07/2023] Open
Abstract
The combined influences of sinoatrial nodal (SAN) pacemaker cell automaticity and its response to autonomic input determine the heart's beating interval variability and mean beating rate. To determine the intrinsic SAN and autonomic signatures buried within EKG RR interval time series change in advanced age, we measured RR interval variability before and during double autonomic blockade at 3-month intervals from 6 months of age until the end of life in long-lived (those that achieved the total cohort median life span of 24 months and beyond) C57/BL6 mice. Prior to 21 months of age, time-dependent changes in intrinsic RR interval variability and mean RR interval were relatively minor. Between 21 and 30 months of age, however, marked changes emerged in intrinsic SAN RR interval variability signatures, pointing to a reduction in the kinetics of pacemaker clock mechanisms, leading to reduced synchronization of molecular functions within and among SAN cells. This loss of high-frequency signal processing within intrinsic SAN signatures resulted in a marked increase in the mean intrinsic RR interval. The impact of autonomic signatures on RR interval variability were net sympathetic and partially compensated for the reduced kinetics of the intrinsic SAN RR interval variability signatures, and partially, but not completely, shifted the EKG RR time series intervals to a more youthful pattern. Cross-sectional analyses of other subsets of C57/BL6 ages indicated that at or beyond the median life span of our longitudinal cohort, noncardiac, constitutional, whole-body frailty was increased, energetic efficiency was reduced, and the respiratory exchange ratio increased. We interpret the progressive reduction in kinetics in intrinsic SAN RR interval variability signatures in this context of whole-body frailty beyond 21 months of age to be a manifestation of "heartbeat frailty."
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Affiliation(s)
- Jack M Moen
- Laboratory of Cardiovascular Science, National Institute On Aging, National Institutes of Health, Baltimore, MD, USA
- Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, CA, USA
| | - Christopher H Morrell
- Laboratory of Cardiovascular Science, National Institute On Aging, National Institutes of Health, Baltimore, MD, USA
| | - Michael G Matt
- Laboratory of Cardiovascular Science, National Institute On Aging, National Institutes of Health, Baltimore, MD, USA
- Pediatric Residency Program, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Ismayil Ahmet
- Laboratory of Cardiovascular Science, National Institute On Aging, National Institutes of Health, Baltimore, MD, USA
| | - Syevda Tagirova
- Laboratory of Cardiovascular Science, National Institute On Aging, National Institutes of Health, Baltimore, MD, USA
| | - Moran Davoodi
- Biomedical Engineering Faculty, Technion-IIT, Haifa, Israel
| | - Michael Petr
- Laboratory of Experimental Gerontology Intramural Research Program, National Institute On Aging, National Institutes of Health, Baltimore, MD, USA
- Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Shaquille Charles
- Laboratory of Cardiovascular Science, National Institute On Aging, National Institutes of Health, Baltimore, MD, USA
| | - Rafael de Cabo
- Laboratory of Experimental Gerontology Intramural Research Program, National Institute On Aging, National Institutes of Health, Baltimore, MD, USA
| | - Yael Yaniv
- Biomedical Engineering Faculty, Technion-IIT, Haifa, Israel
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, National Institute On Aging, National Institutes of Health, Baltimore, MD, USA.
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3
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Rosas PC, Warren CM, Creed HA, Trzeciakowski JP, Solaro RJ, Tong CW. Cardiac Myosin Binding Protein-C Phosphorylation Mitigates Age-Related Cardiac Dysfunction: Hope for Better Aging? JACC Basic Transl Sci 2019; 4:817-830. [PMID: 31998850 PMCID: PMC6978553 DOI: 10.1016/j.jacbts.2019.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 06/14/2019] [Accepted: 06/19/2019] [Indexed: 12/29/2022]
Abstract
Cardiac myosin binding protein-C (cMyBP-C) phosphorylation prevents aging-related cardiac dysfunction. We tested this hypothesis by aging genetic mouse models of hypophosphorylated cMyBP-C, wild-type equivalent, and phosphorylated-mimetic cMyBP-C for 18 to 20 months. Phosphorylated-mimetic cMyBP-C mice exhibited better survival, better preservation of systolic and diastolic functions, and unchanging wall thickness. Wild-type equivalent mice showed decreasing cMyBP-C phosphorylation along with worsening cardiac function and hypertrophy approaching those found in hypophosphorylated cMyBP-C mice. Intact papillary muscle experiments suggested that cMyBP-C phosphorylation increased cross-bridge detachment rates as the underlying mechanism. Thus, phosphorylating cMyBP-C is a novel mechanism with potential to treat aging-related cardiac dysfunction.
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Key Words
- 3SA, mutated 3 serines to 3 alanines to mimic hypophosphorylated cardiac myosin binding protein-C (S273A, S282A, and S302A)
- 3SD, mutated 3 serines to 3 aspartic acids to mimic phosphorylated cMyBP-C (S273D, S282D, and S302D)
- ANOVA, analysis of variance
- EF, ejection fraction
- HF, heart failure
- HFpEF, heart failure with preserved ejection fraction
- HOP, hydroxyproline
- LV, left ventricular
- aging
- cMyBP-C, cardiac myosin binding protein-C
- cTnI, cardiac troponin I
- cardiac myosin binding protein-C
- dyastolic dysfunction
- heart failure
- phosphorylation
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Affiliation(s)
- Paola C. Rosas
- Department of Physiology and Biophysics, Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Chad M. Warren
- Department of Physiology and Biophysics, Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Heidi A. Creed
- Department of Medical Physiology, Texas A and M University Health Science Center, College of Medicine, College Station, Texas
| | - Jerome P. Trzeciakowski
- Department of Medical Physiology, Texas A and M University Health Science Center, College of Medicine, College Station, Texas
| | - R. John Solaro
- Department of Physiology and Biophysics, Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Carl W. Tong
- Department of Medical Physiology, Texas A and M University Health Science Center, College of Medicine, College Station, Texas
- Catholic Health Initiatives-St. Joseph Health, Bryan, Texas
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4
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Green LC, Anthony SR, Slone S, Lanzillotta L, Nieman ML, Wu X, Robbins N, Jones SM, Roy S, Owens AP, Aube J, Xu L, Lorenz JN, Blaxall BC, Rubinstein J, Benoit JB, Tranter M. Human antigen R as a therapeutic target in pathological cardiac hypertrophy. JCI Insight 2019; 4:121541. [PMID: 30668549 DOI: 10.1172/jci.insight.121541] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 01/14/2019] [Indexed: 01/06/2023] Open
Abstract
RNA binding proteins represent an emerging class of proteins with a role in cardiac dysfunction. We show that activation of the RNA binding protein human antigen R (HuR) is increased in the failing human heart. To determine the functional role of HuR in pathological cardiac hypertrophy, we created an inducible cardiomyocyte-specific HuR-deletion mouse and showed that HuR deletion reduces left ventricular hypertrophy, dilation, and fibrosis while preserving cardiac function in a transverse aortic constriction (TAC) model of pressure overload-induced hypertrophy. Assessment of HuR-dependent changes in global gene expression suggests that the mechanistic basis for this protection occurs through a reduction in fibrotic signaling, specifically through a reduction in TGF-β (Tgfb) expression. Finally, pharmacological inhibition of HuR at a clinically relevant time point following the initial development of pathological hypertrophy after TAC also yielded a significant reduction in pathological progression, as marked by a reduction in hypertrophy, dilation, and fibrosis and preserved function. In summary, this study demonstrates a functional role for HuR in the progression of pressure overload-induced cardiac hypertrophy and establishes HuR inhibition as a viable therapeutic approach for pathological cardiac hypertrophy and heart failure.
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Affiliation(s)
- Lisa C Green
- Department of Internal Medicine, Division of Cardiovascular Health and Disease and.,Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Sarah R Anthony
- Department of Internal Medicine, Division of Cardiovascular Health and Disease and
| | - Samuel Slone
- Department of Internal Medicine, Division of Cardiovascular Health and Disease and.,Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Lindsey Lanzillotta
- Department of Internal Medicine, Division of Cardiovascular Health and Disease and
| | - Michelle L Nieman
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Xiaoqing Wu
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Nathan Robbins
- Department of Internal Medicine, Division of Cardiovascular Health and Disease and
| | - Shannon M Jones
- Department of Internal Medicine, Division of Cardiovascular Health and Disease and
| | - Sudeshna Roy
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - A Phillip Owens
- Department of Internal Medicine, Division of Cardiovascular Health and Disease and
| | - Jeffrey Aube
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Liang Xu
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - John N Lorenz
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Burns C Blaxall
- Department of Pediatrics, Division of Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, Ohio, USA
| | - Jack Rubinstein
- Department of Internal Medicine, Division of Cardiovascular Health and Disease and
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, USA
| | - Michael Tranter
- Department of Internal Medicine, Division of Cardiovascular Health and Disease and
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5
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Age-Dependent Protein Expression of Serine/Threonine Phosphatases and Their Inhibitors in the Human Cardiac Atrium. Adv Med 2019; 2019:2675972. [PMID: 30719459 PMCID: PMC6334353 DOI: 10.1155/2019/2675972] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 11/22/2018] [Accepted: 11/29/2018] [Indexed: 12/20/2022] Open
Abstract
Heart failure and aging of the heart show many similarities regarding hemodynamic and biochemical parameters. There is evidence that heart failure in experimental animals and humans is accompanied and possibly exacerbated by increased activity of protein phosphatase (PP) 1 and/or 2A. Here, we wanted to study the age-dependent protein expression of major members of the protein phosphatase family in human hearts. Right atrial samples were obtained during bypass surgery. Patients (n=60) were suffering from chronic coronary artery disease (CCS 2-3; New York Heart Association (NYHA) stage 1-3). Age ranged from 48 to 84 years (median 69). All patients included in the study were given β-adrenoceptor blockers. Other medications included angiotensin-converting enzyme (ACE) or angiotensin-receptor-1 (AT1) inhibitors, statins, nitrates, and acetylsalicylic acid (ASS). 100 µg of right atrial homogenates was used for western blotting. Antibodies against catalytic subunits (and their major regulatory proteins) of all presently known cardiac serine/threonine phosphatases were used for antigen detection. In detail, we studied the expression of the catalytic subunit of PP1 (PP1c); I1 PP1 and I2 PP1, proteins that can inhibit the activity of PP1c; the catalytic subunit of PP2A (PP2Ac); regulatory A-subunit of PP2A (PP2AA); regulatory B56α-subunit of PP2A (PP2AB); I1 PP2A and I2 PP2A, inhibitory subunits of PP2A; catalytic and regulatory subunits of calcineurin: PP2BA and PP2BB; PP2C; PP5; and PP6. All data were obtained within the linear range of the assay. There was a significant decline in PP2Ac and I2 PP2A expression in older patients, whereas all other parameters remained unchanged with age. It remains to be elucidated whether the decrease in the protein expression of I2 PP2A might elevate cardiac PP2A activity in a detrimental way or is overcome by a reduced protein expression and thus a reduced activity of PP2Ac.
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6
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Huang W, Liang J, Feng Y, Jia Z, Jiang L, Cai W, Paul C, Gu JG, Stambrook PJ, Millard RW, Zhu XL, Zhu P, Wang Y. Heterogeneity of adult masseter muscle satellite cells with cardiomyocyte differentiation potential. Exp Cell Res 2018; 371:20-30. [PMID: 29842877 PMCID: PMC7291879 DOI: 10.1016/j.yexcr.2018.05.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 05/21/2018] [Accepted: 05/24/2018] [Indexed: 01/25/2023]
Abstract
Although resident cardiac stem cells have been reported, regeneration of functional cardiomyocytes (CMs) remains a challenge. The present study identifies an alternative progenitor source for CM regeneration without the need for genetic manipulation or invasive heart biopsy procedures. Unlike limb skeletal muscles, masseter muscles (MM) in the mouse head are developed from Nkx2-5 mesodermal progenitors. Adult masseter muscle satellite cells (MMSCs) display heterogeneity in developmental origin and cell phenotypes. The heterogeneous MMSCs that can be characterized by cell sorting based on stem cell antigen-1 (Sca1) show different lineage potential. While cardiogenic potential is preserved in Sca1+ MMSCs as shown by expression of cardiac progenitor genes (including Nkx2-5), skeletal myogenic capacity is maintained in Sca1- MMSCs with Pax7 expression. Sca1+ MMSC-derived beating cells express cardiac genes and exhibit CM-like morphology. Electrophysiological properties of MMSC-derived CMs are demonstrated by calcium transients and action potentials. These findings show that MMSCs could serve as a novel cell source for cardiomyocyte replacement.
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Affiliation(s)
- Wei Huang
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jialiang Liang
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Yuliang Feng
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Zhanfeng Jia
- Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Lin Jiang
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Wenfeng Cai
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Christian Paul
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jianguo G Gu
- Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Peter J Stambrook
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Ronald W Millard
- Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Xiao-Lan Zhu
- Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Ping Zhu
- Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China.
| | - Yigang Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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7
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Neef S, Heijman J, Otte K, Dewenter M, Saadatmand AR, Meyer-Roxlau S, Antos CL, Backs J, Dobrev D, Wagner M, Maier LS, El-Armouche A. Chronic loss of inhibitor-1 diminishes cardiac RyR2 phosphorylation despite exaggerated CaMKII activity. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2017; 390:857-862. [PMID: 28451724 DOI: 10.1007/s00210-017-1376-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 04/06/2017] [Indexed: 10/19/2022]
Abstract
Inhibitor-1 (I-1) modulates protein phosphatase 1 (PP1) activity and thereby counteracts the phosphorylation by kinases. I-1 is downregulated and deactivated in failing hearts, but whether its role is beneficial or detrimental remains controversial, and opposing therapeutic strategies have been proposed. Overactivity of Ca2+/calmodulin-dependent protein kinase II (CaMKII) with hyperphosphorylation of ryanodine receptors (RyR2) at the CaMKII-site is recognized to be central for heart failure and arrhythmias. Using an I-1-deficient mouse line as well as transfected cell lines, we investigated the effects of acute and chronic modulation of I-1 on CaMKII activity and RyR2 phosphorylation. We demonstrate that I-1 acutely modulates CaMKII by regulating PP1 activity. However, while ablation of I-1 should thus limit CaMKII-activation, we unexpectedly found exaggerated CaMKII-activation under β-adrenergic stress upon chronic loss of I-1 in knockout mice. We unraveled that this is due to chronic upregulation of the exchange protein activated by cAMP (EPAC) leading to augmented CaMKII activation, and using computational modeling validated that an increase in EPAC expression can indeed explain our experimental findings. Interestingly, at the level of RyR2, the increase in PP1 activity more than outweighed the increase in CaMKII activity, resulting in reduced RyR phosphorylation at Ser-2814. Exaggerated CaMKII activation due to counterregulatory mechanisms upon loss of I-1 is an important caveat with respect to suggested therapeutic I-1-inhibition, as CaMKII overactivity has been heavily implicated in several cardiac pathologies.
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Affiliation(s)
- Stefan Neef
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Jordi Heijman
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
| | - Kristian Otte
- Department of Pharmacology and Toxicology, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Matthias Dewenter
- Department of Pharmacology and Toxicology, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany.,Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Ali R Saadatmand
- Department of Pharmacology and Toxicology, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany.,Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Stefanie Meyer-Roxlau
- Department of Pharmacology and Toxicology, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Christopher L Antos
- Department of Pharmacology and Toxicology, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Johannes Backs
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Michael Wagner
- Department of Pharmacology and Toxicology, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Ali El-Armouche
- Department of Pharmacology and Toxicology, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany.
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8
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Weber S, Meyer-Roxlau S, El-Armouche A. Role of protein phosphatase inhibitor-1 in cardiac beta adrenergic pathway. J Mol Cell Cardiol 2016; 101:116-126. [PMID: 27639308 DOI: 10.1016/j.yjmcc.2016.09.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/05/2016] [Accepted: 09/13/2016] [Indexed: 01/08/2023]
Abstract
Phosphoproteomic studies have shown that about one third of all cardiac proteins are reversibly phosphorylated, affecting virtually every cellular signaling pathway. The reversibility of this process is orchestrated by the opposing enzymatic activity of kinases and phosphatases. Conversely, imbalances in subcellular protein phosphorylation patterns are a hallmark of many cardiovascular diseases including heart failure and cardiac arrhythmias. While numerous studies have revealed excessive beta-adrenergic signaling followed by deregulated kinase expression or activity as a major driver of the latter cardiac pathologies, far less is known about the beta-adrenergic regulation of their phosphatase counterparts. In fact, most of the limited knowledge stems from the detailed analysis of the endogenous inhibitor of the protein phosphatase 1 (I-1) in cellular and animal models. I-1 acts as a nodal point between adrenergic and putatively non-adrenergic cardiac signaling pathways and is able to influence widespread cellular functions of protein phosphatase 1 which are contributing to cardiac health and disease, e.g. Ca2+ handling, sarcomere contractility and glucose metabolism. Finally, nearly all of these studies agree that I-1 is a promising drug target on the one hand but the outcome of its pharmacological regulation maybe extremely context-dependent on the other hand, thus warranting for careful interpretation of past and future experimental results. In this respect we will: 1) comprehensively review the current knowledge about structural, functional and regulatory properties of I-1 within the heart 2) highlight current working hypothesis and potential I-1 mediated disease mechanisms 3) discuss state-of-the-art knowledge and future prospects of a potential therapeutic strategy targeting I-1 by restoring the balance of cardiac protein phosphorylation.
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Affiliation(s)
- Silvio Weber
- Department of Pharmacology and Toxicology, Medical Faculty, Technische Universität Dresden, Fetscherstraße 74, Dresden 01307, Germany.
| | - Stefanie Meyer-Roxlau
- Department of Pharmacology and Toxicology, Medical Faculty, Technische Universität Dresden, Fetscherstraße 74, Dresden 01307, Germany
| | - Ali El-Armouche
- Department of Pharmacology and Toxicology, Medical Faculty, Technische Universität Dresden, Fetscherstraße 74, Dresden 01307, Germany.
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9
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Matkovich SJ, Grubb DR, McMullen JR, Woodcock EA. Chronic Contractile Dysfunction without Hypertrophy Does Not Provoke a Compensatory Transcriptional Response in Mouse Hearts. PLoS One 2016; 11:e0158317. [PMID: 27359099 PMCID: PMC4928941 DOI: 10.1371/journal.pone.0158317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/14/2016] [Indexed: 12/03/2022] Open
Abstract
Diseased myocardium from humans and experimental animal models shows heightened expression and activity of a specific subtype of phospholipase C (PLC), the splice variant PLCβ1b. Previous studies from our group showed that increasing PLCβ1b expression in adult mouse hearts by viral transduction was sufficient to cause sustained contractile dysfunction of rapid onset, which was maintained indefinitely in the absence of other pathological changes in the myocardium. We hypothesized that impaired contractility alone would be sufficient to induce a compensatory transcriptional response. Unbiased, comprehensive mRNA-sequencing was performed on 6 biological replicates of rAAV6-treated blank, PLCβ1b and PLCβ1a (closely related but inactive splice variant) hearts 8 weeks after injection, when reduced contractility was manifest in PLCβ1b hearts without evidence of induced hypertrophy. Expression of PLCβ1b resulted in expression changes in only 9 genes at FDR<0.1 when compared with control and these genes appeared unrelated to contractility. Importantly, PLCβ1a caused similar mild expression changes to PLCβ1b, despite a complete lack of effect of this isoform on cardiac contractility. We conclude that contractile depression caused by PLCβ1b activation is largely independent of changes in the transcriptome, and thus that lowered contractility is not sufficient in itself to provoke measurable transcriptomic alterations. In addition, our data stress the importance of a stringent control group to filter out transcriptional changes unrelated to cardiac function.
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Affiliation(s)
- Scot J. Matkovich
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, United States of America
- * E-mail:
| | - David R. Grubb
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
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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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Grubb DR, Crook B, Ma Y, Luo J, Qian HW, Gao XM, Kiriazis H, Du XJ, Gregorevic P, Woodcock EA. The atypical 'b' splice variant of phospholipase Cβ1 promotes cardiac contractile dysfunction. J Mol Cell Cardiol 2015; 84:95-103. [PMID: 25918049 DOI: 10.1016/j.yjmcc.2015.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 10/23/2022]
Abstract
The activity of the early signaling enzyme, phospholipase Cβ1b (PLCβ1b), is selectively elevated in diseased myocardium and activity increases with disease progression. We aimed to establish the contribution of heightened PLCβ1b activity to cardiac pathology. PLCβ1b, the alternative splice variant, PLCβ1a, and a blank virus were expressed in mouse hearts using adeno-associated viral vectors (rAAV6-FLAG-PLCβ1b, rAAV6-FLAG-PLCβ1a, or rAAV6-blank) delivered intravenously (IV). Following viral delivery, FLAG-PLCβ1b was expressed in all of the chambers of the mouse heart and was localized to the sarcolemma. Heightened PLCβ1b expression caused a rapid loss of contractility, 4-6 weeks, that was fully reversed, within 5 days, by inhibition of protein kinase Cα (PKCα). PLCβ1a did not localize to the sarcolemma and did not affect contractile function. Expression of PLCβ1b, but not PLCβ1a, caused downstream dephosphorylation of phospholamban and depletion of the Ca(2+) stores of the sarcoplasmic reticulum. We conclude that heightened PLCβ1b activity observed in diseased myocardium contributes to pathology by PKCα-mediated contractile dysfunction. PLCβ1b is a cardiac-specific signaling system, and thus provides a potential therapeutic target for the development of well-tolerated inotropic agents for use in failing myocardium.
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Affiliation(s)
- David R Grubb
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia
| | - Bryony Crook
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia
| | - Yi Ma
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia
| | - Jieting Luo
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia
| | - Hong Wei Qian
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia
| | - Xiao-Ming Gao
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia
| | - Helen Kiriazis
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia
| | - Xiao-Jun Du
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia
| | - Paul Gregorevic
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia
| | - Elizabeth A Woodcock
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, 3004 Victoria, Australia.
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12
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Simon JN, Chowdhury SAK, Warren CM, Sadayappan S, Wieczorek DF, Solaro RJ, Wolska BM. Ceramide-mediated depression in cardiomyocyte contractility through PKC activation and modulation of myofilament protein phosphorylation. Basic Res Cardiol 2014; 109:445. [PMID: 25280528 DOI: 10.1007/s00395-014-0445-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 09/25/2014] [Accepted: 09/26/2014] [Indexed: 12/16/2022]
Abstract
Although ceramide accumulation in the heart is considered a major factor in promoting apoptosis and cardiac disorders, including heart failure, lipotoxicity and ischemia-reperfusion injury, little is known about ceramide's role in mediating changes in contractility. In the present study, we measured the functional consequences of acute exposure of isolated field-stimulated adult rat cardiomyocytes to C6-ceramide. Exogenous ceramide treatment depressed the peak amplitude and the maximal velocity of shortening without altering intracellular calcium levels or kinetics. The inactive ceramide analog C6-dihydroceramide had no effect on myocyte shortening or [Ca(2+)]i transients. Experiments testing a potential role for C6-ceramide-mediated effects on activation of protein kinase C (PKC) demonstrated evidence for signaling through the calcium-independent isoform, PKCε. We employed 2-dimensional electrophoresis and anti-phospho-peptide antibodies to test whether treatment of the cardiomyocytes with C6-ceramide altered myocyte shortening via PKC-dependent phosphorylation of myofilament proteins. Compared to controls, myocytes treated with ceramide exhibited increased phosphorylation of myosin binding protein-C (cMyBP-C), specifically at Ser273 and Ser302, and troponin I (cTnI) at sites apart from Ser23/24, which could be attenuated with PKC inhibition. We conclude that the altered myofilament response to calcium resulting from multiple sites of PKC-dependent phosphorylation contributes to contractile dysfunction that is associated with cardiac diseases in which elevations in ceramides are present.
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Affiliation(s)
- Jillian N Simon
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago, IL, 60612, USA
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13
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Freire PP, Alves CAB, Deus AFD, Leopoldo APL, Leopoldo AS, Silva DCTD, Tomasi LCD, Campos DHS, Cicogna AC. Obesity does not lead to imbalance between myocardial phospholamban phosphorylation and dephosphorylation. Arq Bras Cardiol 2014; 103:41-50. [PMID: 25120084 PMCID: PMC4126760 DOI: 10.5935/abc.20140083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 02/18/2014] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND The activation of the beta-adrenergic system promotes G protein stimulation that, via cyclic adenosine monophosphate (cAMP), alters the structure of protein kinase A (PKA) and leads to phospholamban (PLB) phosphorylation. This protein participates in the system that controls intracellular calcium in muscle cells, and it is the primary regulator of sarcoplasmic reticulum calcium pump activity. In obesity, the beta-adrenergic system is activated by the influence of increased leptin, therefore, resulting in higher myocardial phospholamban phosphorylation via cAMP-PKA. OBJECTIVE To investigate the involvement of proteins which regulate the degree of PLB phosphorylation due to beta-adrenergic activation in obesity. In the present study, we hypothesized that there is an imbalance between phospholamban phosphorylation and dephosphorylation, with prevalence of protein phosphorylation. METHODS Male Wistar rats were randomly distributed into two groups: control (n = 14), fed with normocaloric diet; and obese (n = 13), fed with a cycle of four unsaturated high-fat diets. Obesity was determined by the adiposity index, and protein expressions of phosphatase 1 (PP-1), PKA, PLB, phosphorylated phospholamban at serine16 (PPLB-Ser16) were assessed by Western blot. RESULTS Obesity caused glucose intolerance, hyperinsulinemia, hypertriglyceridemia, hyperleptinemia and did not alter the protein expression of PKA, PP-1, PLB, PPLB-Ser16. CONCLUSION Obesity does not promote an imbalance between myocardial PLB phosphorylation and dephosphorylation via beta-adrenergic system.
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Affiliation(s)
- Paula Paccielli Freire
- Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Carlos Augusto Barnabe Alves
- Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Adriana Fernandes de Deus
- Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Ana Paula Lima Leopoldo
- Centro de Educação Física e Desportos, Universidade Federal do Espírito Santo, Vitória, ES, Brazil
| | - André Soares Leopoldo
- Centro de Educação Física e Desportos, Universidade Federal do Espírito Santo, Vitória, ES, Brazil
| | | | - Loreta Casquel de Tomasi
- Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Dijon Henrique Salomé Campos
- Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Antonio Carlos Cicogna
- Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil
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14
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Liu J, Sirenko S, Juhaszova M, Sollott SJ, Shukla S, Yaniv Y, Lakatta EG. Age-associated abnormalities of intrinsic automaticity of sinoatrial nodal cells are linked to deficient cAMP-PKA-Ca(2+) signaling. Am J Physiol Heart Circ Physiol 2014; 306:H1385-97. [PMID: 24633551 DOI: 10.1152/ajpheart.00088.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A reduced sinoatrial node (SAN) functional reserve underlies the age-associated decline in heart rate acceleration in response to stress. SAN cell function involves an oscillatory coupled-clock system: the sarcoplasmic reticulum (SR), a Ca(2+) clock, and the electrogenic-sarcolemmal membrane clock. Ca(2+)-activated-calmodulin-adenylyl cyclase/CaMKII-cAMP/PKA-Ca(2+) signaling regulated by phosphodiesterase activity drives SAN cells automaticity. SR-generated local calcium releases (LCRs) activate Na(+)/Ca(2+) exchanger in the membrane clock, which initiates the action potential (AP). We hypothesize that SAN cell dysfunctions accumulate with age. We found a reduction in single SAN cell AP firing in aged (20-24 mo) vs. adult (3-4 mo) mice. The sensitivity of the SAN beating rate responses to both muscarinic and adrenergic receptor activation becomes decreased in advanced age. Additionally, age-associated coincident dysfunctions occur stemming from compromised clock functions, including a reduced SR Ca(2+) load and a reduced size, number, and duration of spontaneous LCRs. Moreover, the sensitivity of SAN beating rate to a cAMP stress induced by phosphodiesterase inhibitor is reduced, as are the LCR size, amplitude, and number in SAN cells from aged vs. adult mice. These functional changes coincide with decreased expression of crucial SR Ca(2+)-cycling proteins, including SR Ca(2+)-ATPase pump, ryanodine receptors, and Na(+)/Ca(2+) exchanger. Thus a deterioration in intrinsic Ca(2+) clock kinetics in aged SAN cells, due to deficits in intrinsic SR Ca(2+) cycling and its response to a cAMP-dependent pathway activation, is involved in the age-associated reduction in intrinsic resting AP firing rate, and in the reduction in the acceleration of heart rate during exercise.
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Affiliation(s)
- Jie Liu
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland; and Department of Physiology, University of Sydney, Sydney, New South Wales, Australia
| | - Syevda Sirenko
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland; and
| | - Magdalena Juhaszova
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland; and
| | - Steven J Sollott
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland; and
| | - Shweta Shukla
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland; and
| | - Yael Yaniv
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland; and
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland; and
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15
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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: 39] [Impact Index Per Article: 3.5] [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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16
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Targeted ablation of the histidine-rich Ca(2+)-binding protein (HRC) gene is associated with abnormal SR Ca(2+)-cycling and severe pathology under pressure-overload stress. Basic Res Cardiol 2013; 108:344. [PMID: 23553082 DOI: 10.1007/s00395-013-0344-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 02/15/2013] [Accepted: 03/05/2013] [Indexed: 10/27/2022]
Abstract
The histidine-rich Ca(2+)-binding protein (HRC) is located in the lumen of the sarcoplasmic reticulum (SR) and exhibits high-capacity Ca(2+)-binding properties. Overexpression of HRC in the heart resulted in impaired SR Ca(2+) uptake and depressed relaxation through its interaction with SERCA2a. However, the functional significance of HRC in overall regulation of calcium cycling and contractility is not currently well defined. To further elucidate the role of HRC in vivo under physiological and pathophysiological conditions, we generated and characterized HRC-knockout (KO) mice. The KO mice were morphologically and histologically normal compared to wild-type (WT) mice. At the cellular level, ablation of HRC resulted in significantly enhanced contractility, Ca(2+) transients, and maximal SR Ca(2+) uptake rates in the heart. However, after-contractions were developed in 50 % of HRC-KO cardiomyocytes, compared to 11 % in WT mice under stress conditions of high-frequency stimulation (5 Hz) and isoproterenol application. A parallel examination of the electrical activity revealed significant increases in the occurrence of Ca(2+) spontaneous SR Ca(2+) release and delayed afterdepolarizations with ISO in HRC-KO, compared to WT cells. The frequency of Ca(2+) sparks was also significantly higher in HRC-KO cells with ISO, consistent with the elevated SR Ca(2+) load in the KO cells. Furthermore, HRC-KO cardiomyocytes showed significantly deteriorated cell contractility and Ca(2+)-cycling caused possibly by depressed SERCA2a expression after transverse-aortic constriction (TAC). Also HRC-null mice exhibited severe cardiac hypertrophy, fibrosis, pulmonary edema and decreased survival after TAC. Our results indicate that ablation of HRC is associated with poorly regulated SR Ca(2+)-cycling, and severe pathology under pressure-overload stress, suggesting an essential role of HRC in maintaining the integrity of cardiac function.
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17
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Fish KM, Ladage D, Kawase Y, Karakikes I, Jeong D, Ly H, Ishikawa K, Hadri L, Tilemann L, Muller-Ehmsen J, Samulski RJ, Kranias EG, Hajjar RJ. AAV9.I-1c delivered via direct coronary infusion in a porcine model of heart failure improves contractility and mitigates adverse remodeling. Circ Heart Fail 2012; 6:310-7. [PMID: 23271792 DOI: 10.1161/circheartfailure.112.971325] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Heart failure is characterized by impaired function and disturbed Ca2+ homeostasis. Transgenic increases in inhibitor-1 activity have been shown to improve Ca2 cycling and preserve cardiac performance in the failing heart. The aim of this study was to evaluate the effect of activating the inhibitor (I-1c) of protein phosphatase 1 (I-1) through gene transfer on cardiac function in a porcine model of heart failure induced by myocardial infarction. METHODS AND RESULTS Myocardial infarction was created by a percutaneous, permanent left anterior descending artery occlusion in Yorkshire Landrace swine (n=16). One month after myocardial infarction, pigs underwent intracoronary delivery of either recombinant adeno-associated virus type 9 carrying I-1c (n=8) or saline (n=6) as control. One month after myocardial infarction was created, animals exhibited severe heart failure demonstrated by decreased ejection fraction (46.4±7.0% versus sham 69.7±8.5%) and impaired (dP/dt)max and (dP/dt)min. Intracoronary injection of AAV9.I-1c prevented further deterioration of cardiac function and led to a decrease in scar size. CONCLUSIONS In this preclinical model of heart failure, overexpression of I-1c by intracoronary in vivo gene transfer preserved cardiac function and reduced the scar size.
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Affiliation(s)
- Kenneth M Fish
- Department of Cardiology, Cardiovascular Research Center, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA
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18
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Rienzo M, Bizé A, Pongas D, Michineau S, Melka J, Chan HL, Sambin L, Su JB, Dubois-Randé JL, Hittinger L, Berdeaux A, Ghaleh B. Impaired left ventricular function in the presence of preserved ejection in chronic hypertensive conscious pigs. Basic Res Cardiol 2012; 107:298. [PMID: 22961595 DOI: 10.1007/s00395-012-0298-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/23/2012] [Accepted: 08/24/2012] [Indexed: 12/28/2022]
Abstract
Systolic function is often evaluated by measuring ejection fraction and its preservation is often assimilated with the lack of impairment of systolic left ventricular (LV) function. Considering the left ventricle as a muscular pump, we explored LV function during chronic hypertension independently of increased afterload conditions. Fourteen conscious and chronically instrumented pigs received continuous infusion of either angiotensin II (n = 8) or saline (n = 6) during 28 days. Hemodynamic recordings were regularly performed in the presence and 1 h after stopping angiotensin II infusion to evaluate intrinsic LV function. Throughout the protocol, the mean arterial pressure steadily increased by 55 ± 4 mmHg in angiotensin II-treated animals. There were no significant changes in stroke volume, LV fractional shortening or LV wall thickening, indicating the lack of alterations in LV ejection. In contrast, we observed maladaptive changes with (1) the lack of reduction in isovolumic contraction and relaxation durations with heart rate increases, (2) abnormally blunted isovolumic contraction and relaxation responses to dobutamine and (3) a linear correlation between isovolumic contraction and relaxation durations. None of these changes were observed in saline-infused animals. In conclusion, we provide evidence of impaired LV function with concomitant isovolumic contraction and relaxation abnormalities during chronic hypertension while ejection remains preserved and no sign of heart failure is present. The evaluation under unloaded conditions shows intrinsic LV abnormalities.
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Affiliation(s)
- Mario Rienzo
- Faculté de Médecine, INSERM Unité U, Créteil, France
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