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Complex functionality of protein phosphatase 1 isoforms in the heart. Cell Signal 2021; 85:110059. [PMID: 34062239 DOI: 10.1016/j.cellsig.2021.110059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 05/21/2021] [Accepted: 05/28/2021] [Indexed: 02/04/2023]
Abstract
Protein phosphatase 1(PP1) is a key regulator of cardiac function through dephosphorylating serine/threonine residues within target proteins to oppose the function of protein kinases. Studies from failing hearts of animal models and human patients have demonstrated significant increase of PP1 activity in myocardium, while elevated PP1 activity in transgenic mice leads to cardiac dysfunction, suggesting that PP1 might be a therapeutic target to ameliorate cardiac dysfunction in failing hearts. In fact, cardiac overexpression of inhibitor 1, the endogenous inhibitor of PP1, increases cardiac contractility and suppresses heart failure progression. However, this notion of PP1 inhibition for heart failure treatment has been challenged by recent studies on the isoform-specific roles of PP1 in the heart. PP1 is a holoenzyme composed of catalytic subunits (PP1α, PP1β, or PP1γ) and regulatory proteins that target them to distinct subcellular locations for functional specificity. This review will summarize how PP1 regulates phosphorylation of some of the key cardiac proteins involved in Ca2+ handling and cardiac contraction, and the potential role of PP1 isoforms in controlling cardiac physiology and pathophysiology.
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2
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Casamayor A, Ariño J. Controlling Ser/Thr protein phosphatase PP1 activity and function through interaction with regulatory subunits. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020; 122:231-288. [PMID: 32951813 DOI: 10.1016/bs.apcsb.2020.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein phosphatase 1 is a major Ser/Thr protein phosphatase activity in eukaryotic cells. It is composed of a catalytic polypeptide (PP1C), with little substrate specificity, that interacts with a large variety of proteins of diverse structure (regulatory subunits). The diversity of holoenzymes that can be formed explain the multiplicity of cellular functions under the control of this phosphatase. In quite a few cases, regulatory subunits have an inhibitory role, downregulating the activity of the phosphatase. In this chapter we shall introduce PP1C and review the most relevant families of PP1C regulatory subunits, with particular emphasis in describing the structural basis for their interaction.
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Affiliation(s)
- Antonio Casamayor
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola, del Vallès, Spain
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola, del Vallès, Spain
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3
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Hamilton S, Terentyev D. Altered Intracellular Calcium Homeostasis and Arrhythmogenesis in the Aged Heart. Int J Mol Sci 2019; 20:ijms20102386. [PMID: 31091723 PMCID: PMC6566636 DOI: 10.3390/ijms20102386] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 04/29/2019] [Accepted: 05/08/2019] [Indexed: 12/17/2022] Open
Abstract
Aging of the heart is associated with a blunted response to sympathetic stimulation, reduced contractility, and increased propensity for arrhythmias, with the risk of sudden cardiac death significantly increased in the elderly population. The altered cardiac structural and functional phenotype, as well as age-associated prevalent comorbidities including hypertension and atherosclerosis, predispose the heart to atrial fibrillation, heart failure, and ventricular tachyarrhythmias. At the cellular level, perturbations in mitochondrial function, excitation-contraction coupling, and calcium homeostasis contribute to this electrical and contractile dysfunction. Major determinants of cardiac contractility are the intracellular release of Ca2+ from the sarcoplasmic reticulum by the ryanodine receptors (RyR2), and the following sequestration of Ca2+ by the sarco/endoplasmic Ca2+-ATPase (SERCa2a). Activity of RyR2 and SERCa2a in myocytes is not only dependent on expression levels and interacting accessory proteins, but on fine-tuned regulation via post-translational modifications. In this paper, we review how aberrant changes in intracellular Ca2+ cycling via these proteins contributes to arrhythmogenesis in the aged heart.
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Affiliation(s)
- Shanna Hamilton
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
| | - Dmitry Terentyev
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
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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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Ji Y, Wang T, Zhang X, Li L, Li L, Guo Y, Yang B, Wang Y, Zhu T. Astragalosides increase the cardiac diastolic function and regulate the "Calcium sensing receptor-protein kinase C-protein phosphatase 1" pathway in rats with heart failure. Biomed Pharmacother 2018; 103:838-843. [PMID: 29710499 DOI: 10.1016/j.biopha.2018.04.111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/11/2018] [Accepted: 04/13/2018] [Indexed: 02/06/2023] Open
Abstract
This study was designed to investigate the effects of astragalosides on cardiac diastolic function, and an emphasis was placed on the variation of the upstream molecular regulators of phospholamban. Chronic heart failure (CHF) rats were induced by ligaturing the left anterior coronary artery, and rats in the therapeutic groups were treated with either a 50 mg/kg dose of captopril, 10 mg/kg dose of astragalosides or 20 mg/kg dose of astragalosides. Four weeks after treatment, the ratio of the early and atrial peak filling velocities (E/A) and maximal slope diastolic pressure decrement (-dp/dt) both decreased in CHF rats (by 30.3% and 25.5%, respectively) and significantly increased in 20 mg/kg astragalosides and captopril-treated rats. The protein phosphatase-1 activity was lower in the 20 mg/kg astragalosides group than in the CHF group (0.22 vs 0.44, P < 0.01), and the inhibitor-1 levels in the astragalosides and captopril-treated groups were increased. Chronic heart failure increased expression of protein kinase C-α and calcium-sensing receptor, and these changes were attenuated by astragalosides therapy. Astragalosides restored the diastolic dysfunction of chronic heart failure rats, possibly by downregulation of calcium-sensing receptor and protein kinase C-α, which in turn augmented inhibitor-1 expression, reduced protein phosphatase-1 activity and increased phospholamban phosphorylation.
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Affiliation(s)
- Yansu Ji
- Affiliated Hospital of Logistics University of Chinese People's Armed Police Force, Tianjin 300162, China
| | - Tianqi Wang
- Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Xiting Zhang
- Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Lailai Li
- Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Liang Li
- Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Yisha Guo
- Affiliated Hospital of Logistics University of Chinese People's Armed Police Force, Tianjin 300162, China
| | - Bo Yang
- Affiliated Hospital of Logistics University of Chinese People's Armed Police Force, Tianjin 300162, China
| | - Yi Wang
- Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Tieliang Zhu
- Affiliated Hospital of Logistics University of Chinese People's Armed Police Force, Tianjin 300162, China.
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Schwab DM, Tilemann L, Bauer R, Heckmann M, Jungmann A, Wagner M, Burgis J, Vettel C, Katus HA, El-Armouche A, Müller OJ. AAV-9 mediated phosphatase-1 inhibitor-1 overexpression improves cardiac contractility in unchallenged mice but is deleterious in pressure-overload. Gene Ther 2018; 25:13-19. [DOI: 10.1038/gt.2017.97] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 10/16/2017] [Accepted: 11/20/2017] [Indexed: 11/09/2022]
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Bidwell PA, Liu GS, Nagarajan N, Lam CK, Haghighi K, Gardner G, Cai WF, Zhao W, Mugge L, Vafiadaki E, Sanoudou D, Rubinstein J, Lebeche D, Hajjar R, Sadoshima J, Kranias EG. HAX-1 regulates SERCA2a oxidation and degradation. J Mol Cell Cardiol 2018; 114:220-233. [PMID: 29169992 PMCID: PMC5801168 DOI: 10.1016/j.yjmcc.2017.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/30/2017] [Accepted: 11/19/2017] [Indexed: 01/14/2023]
Abstract
Ischemia/reperfusion injury is associated with contractile dysfunction and increased cardiomyocyte death. Overexpression of the hematopoietic lineage substrate-1-associated protein X-1 (HAX-1) has been shown to protect from cellular injury but the function of endogenous HAX-1 remains obscure due to early lethality of the knockout mouse. Herein we generated a cardiac-specific and inducible HAX-1 deficient model, which uncovered an unexpected role of HAX-1 in regulation of sarco/endoplasmic reticulum Ca-ATPase (SERCA2a) in ischemia/reperfusion injury. Although ablation of HAX-1 in the adult heart elicited no morphological alterations under non-stress conditions, it diminished contractile recovery and increased infarct size upon ischemia/reperfusion injury. These detrimental effects were associated with increased loss of SERCA2a. Enhanced SERCA2a degradation was not due to alterations in calpain and calpastatin levels or calpain activity. Conversely, HAX-1 overexpression improved contractile recovery and maintained SERCA2a levels. The regulatory effects of HAX-1 on SERCA2a degradation were observed at multiple levels, including intact hearts, isolated cardiomyocytes and sarcoplasmic reticulum microsomes. Mechanistically, HAX-1 ablation elicited increased production of reactive oxygen species at the sarco/endoplasic reticulum compartment, resulting in SERCA2a oxidation and a predisposition to its proteolysis. This effect may be mediated by NAPDH oxidase 4 (NOX4), a novel binding partner of HAX-1. Accordingly, NOX inhibition with apocynin abrogated the effects of HAX-1 ablation in hearts subjected to ischemia/reperfusion injury. Taken together, our findings reveal a role of HAX-1 in the regulation of oxidative stress and SERCA2a degradation, implicating its importance in calcium homeostasis and cell survival pathways.
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Affiliation(s)
- Philip A Bidwell
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - Guan-Sheng Liu
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - Narayani Nagarajan
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Chi Keung Lam
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - Kobra Haghighi
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - George Gardner
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - Wen-Feng Cai
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - Wen Zhao
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - Luke Mugge
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece; 4th Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Jack Rubinstein
- Division of Cardiology, Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Djamel Lebeche
- Cardiovascular Research Center, Ichan School of Medicine at Mount Sinai, New York, NY, USA
| | - Roger Hajjar
- Cardiovascular Research Center, Ichan School of Medicine at Mount Sinai, New York, NY, USA
| | - Junichi Sadoshima
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA; Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece.
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8
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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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9
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Haileselassie B, Su E, Pozios I, Niño DF, Liu H, Lu DY, Ventoulis I, Fulton WB, Sodhi CP, Hackam D, O'Rourke B, Abraham T. Myocardial oxidative stress correlates with left ventricular dysfunction on strain echocardiography in a rodent model of sepsis. Intensive Care Med Exp 2017; 5:21. [PMID: 28405943 PMCID: PMC5389950 DOI: 10.1186/s40635-017-0134-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 04/04/2017] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Recognition of cardiomyopathy in sepsis can be challenging due to the limitations of conventional measures such as ejection fraction (EF) and fractional shortening (FS) in the context of variable preload and afterload conditions. This study correlates myocardial function using strain echocardiography (SE) with cardiomyocyte oxidative stress in a murine model of sepsis. METHODS C57BL/6J mice were randomized into control (n = 10), sham (n = 25), and a cecal ligation and puncture (CLP) (n = 33) model of sepsis. Echocardiography was performed pre-, 12, 24, and 48 h post-injury. Cardiac pro-inflammatory cytokines and mitochondrial redox scavenger expression were evaluated in a subset of each arm. To evaluate the influence of redox scavenger upregulation on oxidative injury and cardiac function, CLP was performed on mitochondrial catalase-upregulated C57BL/6J MCAT+/+ mice (n = 12) and wild-type (WT) animals for comparison. RESULTS Septic C57BL/6J mice exhibited depressed longitudinal strain (LS) when compared to sham and control at 24 h (p < 0.01) and 48 h (p = 0.04) post-CLP despite having a preserved EF. Furthermore, there was a significant association between increased odds of mortality and depressed LS (OR = 1.23, p = 0.04). Septic C57BL/6J mice concomitantly demonstrated increased expression of cardiomyocyte pro-inflammatory cytokines and decreased expression of redox scavengers at 24 and 48 h. When comparing C57Bl/6 MCAT +/+ mice and C57BL/6J WT mice, a significant decrease in LS was identified in the WT mice at 24 h (MCAT = -23 ± 5% vs. WT = -15 ± 4% p < 0.01) and 48 h (MCAT = -23 ± 7% vs. WT = -15 ± 4.3% p = 0.04) post-CLP which correlated with significant increase in the level of cardiac oxidative stress following CLP. CONCLUSIONS In this sepsis model, SE identified cardiomyopathy despite normal EF. SE depression temporally coincides with upregulation of inflammatory cytokines and decreases expression of key mitochondrial ROS scavengers. Upregulation of redox scavenger (CAT) abrogates oxidative stress and cardiac dysfunction in this sepsis model.
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Affiliation(s)
- Bereketeab Haileselassie
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Department of Pediatrics, Division of Critical Care, Stanford University School of Medicine, 770 Welch Road, Suite 435, Palo Alto, CA, 94304-5731, USA.
| | - Erik Su
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Iraklis Pozios
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Diego F Niño
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hongyun Liu
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dai-Yin Lu
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ioannis Ventoulis
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - William B Fulton
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chhinder P Sodhi
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David Hackam
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Brian O'Rourke
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Theodore Abraham
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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10
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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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11
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Haghighi K, Pritchard TJ, Liu GS, Singh VP, Bidwell P, Lam CK, Vafiadaki E, Das P, Ma J, Kunduri S, Sanoudou D, Florea S, Vanderbilt E, Wang HS, Rubinstein J, Hajjar RJ, Kranias EG. Human G109E-inhibitor-1 impairs cardiac function and promotes arrhythmias. J Mol Cell Cardiol 2015; 89:349-59. [PMID: 26455482 PMCID: PMC4689614 DOI: 10.1016/j.yjmcc.2015.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 09/18/2015] [Accepted: 10/04/2015] [Indexed: 01/09/2023]
Abstract
A hallmark of human and experimental heart failure is deficient sarcoplasmic reticulum (SR) Ca-uptake reflecting impaired contractile function. This is at least partially attributed to dephosphorylation of phospholamban by increased protein phosphatase 1 (PP1) activity. Indeed inhibition of PP1 by transgenic overexpression or gene-transfer of constitutively active inhibitor-1 improved Ca-cycling, preserved function and decreased fibrosis in small and large animal models of heart failure, suggesting that inhibitor-1 may represent a potential therapeutic target. We recently identified a novel human polymorphism (G109E) in the inhibitor-1 gene with a frequency of 7% in either normal or heart failure patients. Transgenic mice, harboring cardiac-specific expression of G109E inhibitor-1, exhibited decreases in contractility, Ca-kinetics and SR Ca-load. These depressive effects were relieved by isoproterenol stimulation. Furthermore, stress conditions (2Hz +/- Iso) induced increases in Ca-sparks, Ca-waves (60% of G109E versus 20% in wild types) and after-contractions (76% of G109E versus 23% of wild types) in mutant cardiomyocytes. Similar findings were obtained by acute expression of the G109E variant in adult cardiomyocytes in the absence or presence of endogenous inhibitor-1. The underlying mechanisms included reduced binding of mutant inhibitor-1 to PP1, increased PP1 activity, and dephosphorylation of phospholamban at Ser16 and Thr17. However, phosphorylation of the ryanodine receptor at Ser2808 was not altered while phosphorylation at Ser2814 was increased, consistent with increased activation of Ca/calmodulin-dependent protein kinase II (CaMKII), promoting aberrant SR Ca-release. Parallel in vivo studies revealed that mutant mice developed ventricular ectopy and complex ventricular arrhythmias (including bigeminy, trigeminy and ventricular tachycardia), when challenged with isoproterenol. Inhibition of CaMKII activity by KN-93 prevented the increased propensity to arrhythmias. These findings suggest that the human G109E inhibitor-1 variant impairs SR Ca-cycling and promotes arrhythmogenesis under stress conditions, which may present an additional insult in the compromised function of heart failure carriers.
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Affiliation(s)
- Kobra Haghighi
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Tracy J Pritchard
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Guan-Sheng Liu
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Vivek P Singh
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Philip Bidwell
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Chi Keung Lam
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Greece
| | - Parthib Das
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Jianyong Ma
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Swati Kunduri
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Greece; 4th Department of Internal Medicine, Medical School, University of Athens and Attikon Hospital, Greece
| | - Stela Florea
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Erica Vanderbilt
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Hong-Shang Wang
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States
| | - Jack Rubinstein
- Division of Cardiology, Internal Medicine, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, United States
| | - Roger J Hajjar
- Cardiovascular Research Center, Ichan School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, United States
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, United States; Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Greece.
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12
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Cai WF, Liu GS, Lam CK, Florea S, Qian J, Zhao W, Pritchard T, Haghighi K, Lebeche D, Lu LJ, Deng J, Fan GC, Hajjar RJ, Kranias EG. Up-regulation of micro-RNA765 in human failing hearts is associated with post-transcriptional regulation of protein phosphatase inhibitor-1 and depressed contractility. Eur J Heart Fail 2015; 17:782-93. [PMID: 26177627 DOI: 10.1002/ejhf.323] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/18/2015] [Accepted: 04/17/2015] [Indexed: 11/09/2022] Open
Abstract
AIMS Impaired sarcoplasmic reticulum (SR) Ca(2+) cycling and depressed contractility, a hallmark of human and experimental heart failure, has been partially attributed to increased protein phosphatase 1 (PP-1) activity, associated with down-regulation of its endogenous inhibitor-1. The levels and activity of inhibitor-1 are reduced in failing hearts, contributing to dephosphorylation and inactivation of key calcium cycling proteins. Therefore, we investigated the mechanisms that mediate decreases in inhibitor-1 by post-transcriptional modification. METHODS AND RESULTS Bioinformatics revealed that 17 human microRNAs may serve as modulators of inhibitor-1. However, real-time PCR analysis identified only one of these microRNAs, miR-765, as being increased in human failing hearts concomitant with decreased inhibitor-1 levels. Expression of miR-765 in HEK293 cells or mouse ventricular myocytes confirmed suppression of inhibitor-1 levels through binding of this miR-765 to the 3'-untranslated region of inhibitor-1 mRNA. To determine the functional significance of miR-765 in Ca(2+) cycling, pri-miR-765 as well as a non-translated nucleotide sequence (miR-Ctrl) were expressed in adult mouse ventricular myocytes. The inhibitor-1 expression levels were decreased, accompanied by enhanced PP-1 activity in the miR-765 cardiomyocytes, and these reflected depressed contractile mechanics and Ca(2+) transients, compared with the miR-Ctrl group. The depressive effects were associated with decreases in the phosphorylation of phospholamban and SR Ca(2+) load. These miR-765 negative inotropic effects were abrogated in inhibitor-1-deficient cardiomyocytes, suggesting its apparent specificity for inhibitor-1. CONCLUSIONS miR-765 levels are increased in human failing hearts. Such increases may contribute to depressed cardiac function through reduced inhibitor-1 expression and enhanced PP-1 activity, associated with reduced SR Ca(2+) load.
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Affiliation(s)
- Wen-Feng Cai
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Guan-Sheng Liu
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Chi Keung Lam
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Stela Florea
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jiang Qian
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Wen Zhao
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Tracy Pritchard
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kobra Haghighi
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Djamel Lebeche
- Cardiovascular Research Center, Mount Sinai School of Medicine, New York, NY, USA
| | - Long Jason Lu
- Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH, USA
| | - Jingyuan Deng
- Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH, USA
| | - Guo-Chang Fan
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Roger J Hajjar
- Cardiovascular Research Center, Mount Sinai School of Medicine, New York, NY, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Molecular Biology Division, Center for Basic Research, Foundation for Biomedical Research of the Academy of Athens, Athens, Greece
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13
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Ablorh NAD, Thomas DD. Phospholamban phosphorylation, mutation, and structural dynamics: a biophysical approach to understanding and treating cardiomyopathy. Biophys Rev 2015; 7:63-76. [PMID: 28509982 DOI: 10.1007/s12551-014-0157-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 11/26/2014] [Indexed: 01/16/2023] Open
Abstract
We review the recent development of novel biochemical and spectroscopic methods to determine the site-specific phosphorylation, expression, mutation, and structural dynamics of phospholamban (PLB), in relation to its function (inhibition of the cardiac calcium pump, SERCA2a), with specific focus on cardiac physiology, pathology, and therapy. In the cardiomyocyte, SERCA2a actively transports Ca2+ into the sarcoplasmic reticulum (SR) during relaxation (diastole) to create the concentration gradient that drives the passive efflux of Ca2+ required for cardiac contraction (systole). Unphosphorylated PLB (U-PLB) inhibits SERCA2a, but phosphorylation at S16 and/or T17 (producing P-PLB) changes the structure of PLB to relieve SERCA2a inhibition. Because insufficient SERCA2a activity is a hallmark of heart failure, SERCA2a activation, by gene therapy (Andino et al. 2008; Fish et al. 2013; Hoshijima et al. 2002; Jessup et al. 2011) or drug therapy (Ferrandi et al. 2013; Huang 2013; Khan et al. 2009; Rocchetti et al. 2008; Zhang et al. 2012), is a widely sought goal for treatment of heart failure. This review describes rational approaches to this goal. Novel biophysical assays, using site-directed labeling and high-resolution spectroscopy, have been developed to resolve the structural states of SERCA2a-PLB complexes in vitro and in living cells. Novel biochemical assays, using synthetic standards and multidimensional immunofluorescence, have been developed to quantitate PLB expression and phosphorylation states in cells and human tissues. The biochemical and biophysical properties of U-PLB, P-PLB, and mutant PLB will ultimately resolve the mechanisms of loss of inhibition and gain of inhibition to guide therapeutic development. These assays will be powerful tools for investigating human tissue samples from the Sydney Heart Bank, for the purpose of analyzing and diagnosing specific disorders.
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Affiliation(s)
- Naa-Adjeley D Ablorh
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
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14
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Haghighi K, Bidwell P, Kranias EG. Phospholamban interactome in cardiac contractility and survival: A new vision of an old friend. J Mol Cell Cardiol 2014; 77:160-7. [PMID: 25451386 PMCID: PMC4312245 DOI: 10.1016/j.yjmcc.2014.10.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/06/2014] [Accepted: 10/09/2014] [Indexed: 01/10/2023]
Abstract
Depressed sarcoplasmic reticulum (SR) calcium cycling, reflecting impaired SR Ca-transport and Ca-release, is a key and universal characteristic of human and experimental heart failure. These SR processes are regulated by multimeric protein complexes, including protein kinases and phosphatases as well as their anchoring and regulatory subunits that fine-tune Ca-handling in specific SR sub-compartments. SR Ca-transport is mediated by the SR Ca-ATPase (SERCA2a) and its regulatory phosphoprotein, phospholamban (PLN). Dephosphorylated PLN is an inhibitor of SERCA2a and phosphorylation by protein kinase A (PKA) or calcium-calmodulin-dependent protein kinases (CAMKII) relieves these inhibitory effects. Recent studies identified additional regulatory proteins, associated with PLN, that control SR Ca-transport. These include the inhibitor-1 (I-1) of protein phosphatase 1 (PP1), the small heat shock protein 20 (Hsp20) and the HS-1 associated protein X-1 (HAX1). In addition, the intra-luminal histidine-rich calcium binding protein (HRC) has been shown to interact with both SERCA2a and triadin. Notably, there is physical and direct interaction between these protein players, mediating a fine-cross talk between SR Ca-uptake, storage and release. Importantly, regulation of SR Ca-cycling by the PLN/SERCA interactome does not only impact cardiomyocyte contractility, but also survival and remodeling. Indeed, naturally occurring variants in these Ca-cycling genes modulate their activity and interactions with other protein partners, resulting in depressed contractility and accelerated remodeling. These genetic variants may serve as potential prognostic or diagnostic markers in cardiac pathophysiology.
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Affiliation(s)
- Kobra Haghighi
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
| | - Philip Bidwell
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA.
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