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Liu YB, Wang Q, Song YL, Song XM, Fan YC, Kong L, Zhang JS, Li S, Lv YJ, Li ZY, Dai JY, Qiu ZK. Abnormal phosphorylation / dephosphorylation and Ca 2+ dysfunction in heart failure. Heart Fail Rev 2024; 29:751-768. [PMID: 38498262 DOI: 10.1007/s10741-024-10395-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2024] [Indexed: 03/20/2024]
Abstract
Heart failure (HF) can be caused by a variety of causes characterized by abnormal myocardial systole and diastole. Ca2+ current through the L-type calcium channel (LTCC) on the membrane is the initial trigger signal for a cardiac cycle. Declined systole and diastole in HF are associated with dysfunction of myocardial Ca2+ function. This disorder can be correlated with unbalanced levels of phosphorylation / dephosphorylation of LTCC, endoplasmic reticulum (ER), and myofilament. Kinase and phosphatase activity changes along with HF progress, resulting in phased changes in the degree of phosphorylation / dephosphorylation. It is important to realize the phosphorylation / dephosphorylation differences between a normal and a failing heart. This review focuses on phosphorylation / dephosphorylation changes in the progression of HF and summarizes the effects of phosphorylation / dephosphorylation of LTCC, ER function, and myofilament function in normal conditions and HF based on previous experiments and clinical research. Also, we summarize current therapeutic methods based on abnormal phosphorylation / dephosphorylation and clarify potential therapeutic directions.
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Affiliation(s)
- Yan-Bing Liu
- Interventional Medical Center, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, Shandong Province, China
- Medical College, Qingdao University, Qingdao, China
| | - Qian Wang
- Medical College, Qingdao University, Qingdao, China
| | - Yu-Ling Song
- Department of Pediatrics, Huantai County Hospital of Traditional Chinese Medicine, Zibo, China
| | | | - Yu-Chen Fan
- Medical College, Qingdao University, Qingdao, China
| | - Lin Kong
- Medical College, Qingdao University, Qingdao, China
| | | | - Sheng Li
- Medical College, Qingdao University, Qingdao, China
| | - Yi-Ju Lv
- Medical College, Qingdao University, Qingdao, China
| | - Ze-Yang Li
- Medical College, Qingdao University, Qingdao, China
| | - Jing-Yu Dai
- Department of Oncology, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, Shandong Province, China.
| | - Zhen-Kang Qiu
- Interventional Medical Center, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, Shandong Province, China.
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Neumann J, Hofmann B, Dhein S, Gergs U. Role of Dopamine in the Heart in Health and Disease. Int J Mol Sci 2023; 24:ijms24055042. [PMID: 36902474 PMCID: PMC10003060 DOI: 10.3390/ijms24055042] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/25/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Dopamine has effects on the mammalian heart. These effects can include an increase in the force of contraction, and an elevation of the beating rate and the constriction of coronary arteries. Depending on the species studied, positive inotropic effects were strong, very modest, or absent, or even negative inotropic effects occurred. We can discern five dopamine receptors. In addition, the signal transduction by dopamine receptors and the regulation of the expression of cardiac dopamine receptors will be of interest to us, because this might be a tempting area of drug development. Dopamine acts in a species-dependent fashion on these cardiac dopamine receptors, but also on cardiac adrenergic receptors. We will discuss the utility of drugs that are currently available as tools to understand cardiac dopamine receptors. The molecule dopamine itself is present in the mammalian heart. Therefore, cardiac dopamine might act as an autocrine or paracrine compound in the mammalian heart. Dopamine itself might cause cardiac diseases. Moreover, the cardiac function of dopamine and the expression of dopamine receptors in the heart can be altered in diseases such as sepsis. Various drugs for cardiac and non-cardiac diseases are currently in the clinic that are, at least in part, agonists or antagonists at dopamine receptors. We define the research needs in order to understand dopamine receptors in the heart better. All in all, an update on the role of dopamine receptors in the human heart appears to be clinically relevant, and is thus presented here.
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Affiliation(s)
- Joachim Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, 06097 Halle, Germany
- Correspondence: ; Tel.: +49-345-557-1686; Fax: +49-345-557-1835
| | - Britt Hofmann
- Herzchirurgie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, 06097 Halle, Germany
| | - Stefan Dhein
- Medizinische Fakultät, Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, 04107 Leipzig, Germany
| | - Ulrich Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, 06097 Halle, Germany
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Regulation of Cardiac PKA Signaling by cAMP and Oxidants. Antioxidants (Basel) 2021; 10:antiox10050663. [PMID: 33923287 PMCID: PMC8146537 DOI: 10.3390/antiox10050663] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 12/31/2022] Open
Abstract
Pathologies, such as cancer, inflammatory and cardiac diseases are commonly associated with long-term increased production and release of reactive oxygen species referred to as oxidative stress. Thereby, protein oxidation conveys protein dysfunction and contributes to disease progression. Importantly, trials to scavenge oxidants by systemic antioxidant therapy failed. This observation supports the notion that oxidants are indispensable physiological signaling molecules that induce oxidative post-translational modifications in target proteins. In cardiac myocytes, the main driver of cardiac contractility is the activation of the β-adrenoceptor-signaling cascade leading to increased cellular cAMP production and activation of its main effector, the cAMP-dependent protein kinase (PKA). PKA-mediated phosphorylation of substrate proteins that are involved in excitation-contraction coupling are responsible for the observed positive inotropic and lusitropic effects. PKA-actions are counteracted by cellular protein phosphatases (PP) that dephosphorylate substrate proteins and thus allow the termination of PKA-signaling. Both, kinase and phosphatase are redox-sensitive and susceptible to oxidation on critical cysteine residues. Thereby, oxidation of the regulatory PKA and PP subunits is considered to regulate subcellular kinase and phosphatase localization, while intradisulfide formation of the catalytic subunits negatively impacts on catalytic activity with direct consequences on substrate (de)phosphorylation and cardiac contractile function. This review article attempts to incorporate the current perception of the functionally relevant regulation of cardiac contractility by classical cAMP-dependent signaling with the contribution of oxidant modification.
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Identifying the key regulators that promote cell-cycle activity in the hearts of early neonatal pigs after myocardial injury. PLoS One 2020; 15:e0232963. [PMID: 32730272 PMCID: PMC7392272 DOI: 10.1371/journal.pone.0232963] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 04/24/2020] [Indexed: 12/25/2022] Open
Abstract
Mammalian cardiomyocytes exit the cell cycle shortly after birth. As a result, an occurrence of coronary occlusion-induced myocardial infarction often results in heart failure, postinfarction LV dilatation, or death, and represents one of the most significant public health morbidities worldwide. Interestingly however, the hearts of neonatal pigs have been shown to regenerate following an acute myocardial infarction (MI) occuring on postnatal day 1 (P1); a recovery period which is accompanied by an increased expression of markers for cell-cycle activity, and suggests that early postnatal myocardial regeneration may be driven in part by the MI-induced proliferation of pre-existing cardiomyocytes. In this study, we identified signaling pathways known to regulate the cell cycle, and determined of these, the pathways persistently upregulated in response to MI injury. We identified five pathways (mitogen associated protein kinase [MAPK], Hippo, cyclic [cAMP], Janus kinase/signal transducers and activators of transcription [JAK-STAT], and Ras) which were comprehensively upregulated in cardiac tissues collected on day 7 (P7) and/or P28 of the P1 injury hearts. Several of the initiating master regulators (e.g., CSF1/CSF1R, TGFB, and NPPA) and terminal effector molecules (e.g., ATF4, FOS, RELA/B, ITGB2, CCND1/2/3, PIM1, RAF1, MTOR, NKF1B) in these pathways were persistently upregulated at day 7 through day 28, suggesting there exists at least some degree of regenerative activity up to 4 weeks following MI at P1. Our observations provide a list of key regulators to be examined in future studies targeting cell-cycle activity as an avenue for myocardial regeneration.
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17β-Estradiol and/or estrogen receptor alpha blocks isoproterenol-induced calcium accumulation and hypertrophy via GSK3β/PP2A/NFAT3/ANP pathway. Mol Cell Biochem 2017; 434:181-195. [DOI: 10.1007/s11010-017-3048-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 04/25/2017] [Indexed: 12/13/2022]
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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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7
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Ishikawa K, Fish KM, Tilemann L, Rapti K, Aguero J, Santos-Gallego CG, Lee A, Karakikes I, Xie C, Akar FG, Shimada YJ, Gwathmey JK, Asokan A, McPhee S, Samulski J, Samulski RJ, Sigg DC, Weber T, Kranias EG, Hajjar RJ. Cardiac I-1c overexpression with reengineered AAV improves cardiac function in swine ischemic heart failure. Mol Ther 2014; 22:2038-2045. [PMID: 25023328 DOI: 10.1038/mt.2014.127] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 07/03/2014] [Indexed: 02/07/2023] Open
Abstract
Cardiac gene therapy has emerged as a promising option to treat advanced heart failure (HF). Advances in molecular biology and gene targeting approaches are offering further novel options for genetic manipulation of the cardiovascular system. The aim of this study was to improve cardiac function in chronic HF by overexpressing constitutively active inhibitor-1 (I-1c) using a novel cardiotropic vector generated by capsid reengineering of adeno-associated virus (BNP116). One month after a large anterior myocardial infarction, 20 Yorkshire pigs randomly received intracoronary injection of either high-dose BNP116.I-1c (1.0 × 10(13) vector genomes (vg), n = 7), low-dose BNP116.I-1c (3.0 × 10(12) vg, n = 7), or saline (n = 6). Compared to baseline, mean left ventricular ejection fraction increased by 5.7% in the high-dose group, and by 5.2% in the low-dose group, whereas it decreased by 7% in the saline group. Additionally, preload-recruitable stroke work obtained from pressure-volume analysis demonstrated significantly higher cardiac performance in the high-dose group. Likewise, other hemodynamic parameters, including stroke volume and contractility index indicated improved cardiac function after the I-1c gene transfer. Furthermore, BNP116 showed a favorable gene expression pattern for targeting the heart. In summary, I-1c overexpression using BNP116 improves cardiac function in a clinically relevant model of ischemic HF.
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Affiliation(s)
- Kiyotake Ishikawa
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kenneth M Fish
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Lisa Tilemann
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kleopatra Rapti
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jaume Aguero
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Carlos G Santos-Gallego
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Ahyoung Lee
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Ioannis Karakikes
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Chaoqin Xie
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Fadi G Akar
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Yuichi J Shimada
- Department of Medicine, Beth Israel Medical Center, University Hospital and Manhattan Campus for the Albert Einstein College of Medicine, New York, New York, USA
| | | | - Aravind Asokan
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | | | | | | | - Daniel C Sigg
- Department of Integrative Biology and Physiology, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Thomas Weber
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, Cincinnati, Ohio, USA
| | - Roger J Hajjar
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
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8
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Qiu Z, Zhang W, Fan F, Li H, Wu C, Ye Y, Du Q, Li Z, Hu X, Zhao G, Sun A, Bao Z, Ge J. Rosuvastatin-attenuated heart failure in aged spontaneously hypertensive rats via PKCα/β2 signal pathway. J Cell Mol Med 2014; 16:3052-61. [PMID: 22970977 PMCID: PMC4393733 DOI: 10.1111/j.1582-4934.2012.01632.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 09/04/2012] [Indexed: 01/19/2023] Open
Abstract
There are controversies concerning the capacity of Rosuvastatin to attenuate heart failure in end-stage hypertension. The aim of the study was to show whether the Rosuvastatin might be effective or not for the heart failure treatment. Twenty-one spontaneously hypertensive rats (SHRs) aged 52 weeks with heart failure were randomly divided into three groups: two receiving Rosuvastatin at 20 and 40 mg/kg/day, respectively, and the third, placebo for comparison with seven Wistar-Kyoto rats (WKYs) as controls. After an 8-week treatment, the systolic blood pressure (SBP) and echocardiographic features were evaluated; mRNA level of B-type natriuretic peptide (BNP) and plasma NT-proBNP concentration were measured; the heart tissues were observed under electron microscope (EM); myocardial sarcoplasmic reticulum Ca2+ pump (SERCA-2) activity and mitochondria cytochrome C oxidase (CCO) activity were measured; the expressions of SERCA-2a, phospholamban (PLB), ryanodine receptor2 (RyR2), sodium–calcium exchanger 1 (NCX1), Ca2+/calmodulin-dependent protein kinase II (CaMKII) and protein phosphatase inhibitor-1 (PPI-1) were detected by Western blot and RT-qPCR; and the total and phosphorylation of protein kinase Cα/β (PKCα/β) were measured. Aged SHRs with heart failure was characterized by significantly decreased left ventricular ejection fraction and left ventricular fraction shortening, enhanced left ventricular end-diastolic diameter and LV Volume, accompanied by increased plasma NT-proBNP and elevated BNP gene expression. Damaged myofibrils, vacuolated mitochondria and swollen sarcoplasmic reticulum were observed by EM. Myocardium mitochondria CCO and SERCA-2 activity decreased. The expressions of PLB and NCX1 increased significantly with up-regulation of PPI-1 and down-regulation of CaMKII, whereas that of RyR2 decreased. Rosuvastatin was found to ameliorate the heart failure in aged SHRs and to improve changes in SERCA-2a, PLB, RyR2, NCX1, CaMKII and PPI-1; PKCα/β2 signal pathway to be suppressed; the protective effect of Rosuvastatin to be dose dependent. In conclusion, the heart failure of aged SHRs that was developed during the end stage of hypertension could be ameliorated by Rosuvastatin.
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Affiliation(s)
- Zhaohui Qiu
- Shanghai Institute of Cardiovascular Diseases of Zhongshan Hospital, Fudan University, Shanghai, China
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Pritchard TJ, Kawase Y, Haghighi K, Anjak A, Cai W, Jiang M, Nicolaou P, Pylar G, Karakikes I, Rapti K, Rubinstein J, Hajjar RJ, Kranias EG. Active inhibitor-1 maintains protein hyper-phosphorylation in aging hearts and halts remodeling in failing hearts. PLoS One 2013; 8:e80717. [PMID: 24312496 PMCID: PMC3846572 DOI: 10.1371/journal.pone.0080717] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/16/2013] [Indexed: 01/14/2023] Open
Abstract
Impaired sarcoplasmic reticulum calcium cycling and depressed contractility are key characteristics in heart failure. Defects in sarcoplasmic reticulum function are characterized by decreased SERCA2a Ca-transport that is partially attributable to dephosphorylation of its regulator phospholamban by increased protein phosphatase 1 activity. Inhibition of protein phosphatase 1 through activation of its endogenous inhibitor-1 has been shown to enhance cardiac Ca-handling and contractility as well as protect from pathological stress remodeling in young mice. In this study, we assessed the long-term effects of inducible expression of constitutively active inhibitor-1 in the adult heart and followed function and remodeling through the aging process, up to 20 months. Mice with inhibitor-1 had normal survival and similar function to WTs. There was no overt remodeling as evidenced by measures of left ventricular end-systolic and diastolic diameters and posterior wall dimensions, heart weight to tibia length ratio, and histology. Higher phosphorylation of phospholamban at both Ser16 and Thr17 was maintained in aged hearts with active inhibitor-1, potentially offsetting the effects of elevated Ser2815-phosphorylation in ryanodine receptor, as there were no increases in arrhythmias under stress conditions in 20-month old mice. Furthermore, long-term expression of active inhibitor-1 via recombinant adeno-associated virus type 9 gene transfer in rats with pressure-overload induced heart failure improved function and prevented remodeling, associated with increased phosphorylation of phospholamban at Ser16 and Thr17. Thus, chronic inhibition of protein phosphatase 1, through increases in active inhibitor-1, does not accelerate age-related cardiomyopathy and gene transfer of this molecule in vivo improves function and halts remodeling in the long term.
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Affiliation(s)
- Tracy J. Pritchard
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Yoshiaki Kawase
- Cardiovascular Research Center, Ichan School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Kobra Haghighi
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Ahmad Anjak
- Department of Internal Medicine, Division of Cardiovascular Diseases, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Wenfeng Cai
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Min Jiang
- Department of Internal Medicine, Division of Cardiovascular Diseases, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Persoulla Nicolaou
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - George Pylar
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Ioannis Karakikes
- Cardiovascular Research Center, Ichan School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Kleopatra Rapti
- Cardiovascular Research Center, Ichan School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Jack Rubinstein
- Department of Internal Medicine, Division of Cardiovascular Diseases, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Roger J. Hajjar
- Cardiovascular Research Center, Ichan School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Evangelia G. Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail:
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10
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Lipskaia L, Bobe R, Chen J, Turnbull IC, Lopez JJ, Merlet E, Jeong D, Karakikes I, Ross AS, Liang L, Mougenot N, Atassi F, Lompré AM, Tarzami ST, Kovacic JC, Kranias E, Hajjar RJ, Hadri L. Synergistic role of protein phosphatase inhibitor 1 and sarco/endoplasmic reticulum Ca2+ -ATPase in the acquisition of the contractile phenotype of arterial smooth muscle cells. Circulation 2013; 129:773-85. [PMID: 24249716 DOI: 10.1161/circulationaha.113.002565] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Phenotypic modulation or switching of vascular smooth muscle cells from a contractile/quiescent to a proliferative/synthetic phenotype plays a key role in vascular proliferative disorders such as atherosclerosis and restenosis. Although several calcium handling proteins that control differentiation of smooth muscle cells have been identified, the role of protein phosphatase inhibitor 1 (I-1) in the acquisition or maintenance of the contractile phenotype modulation remains unknown. METHODS AND RESULTS In human coronary arteries, I-1 and sarco/endoplasmic reticulum Ca2+ -ATPase expression is specific to contractile vascular smooth muscle cells. In synthetic cultured human coronary artery smooth muscle cells, protein phosphatase inhibitor 1 (I-1 target) is highly expressed, leading to a decrease in phospholamban phosphorylation, sarco/endoplasmic reticulum Ca2+ -ATPase, and cAMP-responsive element binding activity. I-1 knockout mice lack phospholamban phosphorylation and exhibit vascular smooth muscle cell arrest in the synthetic state with excessive neointimal proliferation after carotid injury, as well as significant modifications of contractile properties and relaxant response to acetylcholine of femoral artery in vivo. Constitutively active I-1 gene transfer decreased neointimal formation in an angioplasty rat model by preventing vascular smooth muscle cell contractile to synthetic phenotype change. CONCLUSIONS I-1 and sarco/endoplasmic reticulum Ca2+ -ATPase synergistically induce the vascular smooth muscle cell contractile phenotype. Gene transfer of constitutively active I-1 is a promising therapeutic strategy for preventing vascular proliferative disorders.
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Affiliation(s)
- Larissa Lipskaia
- Cardiovascular Research Center. Mount Sinai School of Medicine, New York, NY (L. Lipskaia, J.C., I.C.T., D.J., I.K., A.S.R., L. Liang, S.T.T., J.C.K., R.J.H.., L.H.); INSERM UMRS 956, Université Pierre et Marie Curie-Paris 6, Paris, France (L. Lipskaia, E.M., F.A., A.-M.L.); LIA/Transatlantic Cardiovascular Research Center, Université Pierre et Marie Curie/Mount Sinai School of Medicine, New York, NY (L. Lipskaia, J.C., I.C.T., E.M., D.J., I.K., L. Liang, F.A., A.-M.L., S.T.T., J.C.K., R.J.H., L.H.); INSERM U770, University Paris Sud, Le Kremlin-Bicêtre, France (R.B., J.J.L.); PECMV-Université Pierre et Marie Curie-Paris, Paris, France (N.M.); and University of Cincinnati, Cincinnati, OH (E.K.)
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11
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Abstract
Heart failure is one of the leading causes of sudden death in developed countries. While current therapies are mostly aimed at mitigating associated symptoms, novel therapies targeting the subcellular mechanisms underlying heart failure are emerging. Failing hearts are characterized by reduced contractile properties caused by impaired Ca(2+) cycling between the sarcoplasm and sarcoplasmic reticulum (SR). Sarcoplasmic/ endoplasmic reticulum Ca(2+)ATPase 2a (SERCA2a) mediates Ca(2+) reuptake into the SR in cardiomyocytes. Of note, the expression level and/or activity of SERCA2a, translating to the quantity of SR Ca(2+) uptake, are significantly reduced in failing hearts. Normalization of the SERCA2a expression level by gene delivery has been shown to restore hampered cardiac functions and ameliorate associated symptoms in pre-clinical as well as clinical studies. SERCA2a activity can be regulated at multiple levels of a signaling cascade comprised of phospholamban, protein phosphatase 1, inhibitor-1, and PKCα. SERCA2 activity is also regulated by post-translational modifications including SUMOylation and acetylation. In this review, we will highlight the molecular mechanisms underlying the regulation of SERCA2a activity and the potential therapeutic modalities for the treatment of heart failure.
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Affiliation(s)
- Woo Jin Park
- Global Research Laboratory and College of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.
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12
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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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13
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Abstract
Heart disease remains the leading cause of death and disability in the Western world. Current therapies aim at treating the symptoms rather than the subcellular mechanisms, underlying the etiology and pathological remodeling in heart failure. A universal characteristic, contributing to the decreased contractile performance in human and experimental failing hearts, is impaired calcium sequestration into the sarcoplasmic reticulum (SR). SR calcium uptake is mediated by a Ca(2+)-ATPase (SERCA2), whose activity is reversibly regulated by phospholamban (PLN). Dephosphorylated PLN is an inhibitor of SERCA and phosphorylation of PLN relieves this inhibition. However, the initial simple view of a PLN/SERCA regulatory complex has been modified by our recent identification of SUMO, S100 and the histidine-rich Ca-binding protein as regulators of SERCA activity. In addition, PLN activity is regulated by 2 phosphoproteins, the inhibitor-1 of protein phosphatase 1 and the small heat shock protein 20, which affect the overall SERCA-mediated Ca-transport. This review will highlight the regulatory mechanisms of cardiac contractility by the multimeric SERCA/PLN-ensemble and the potential for new therapeutic avenues targeting this complex by using small molecules and gene transfer methods.
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Affiliation(s)
- Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0575, USA.
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14
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Florea S, Anjak A, Cai WF, Qian J, Vafiadaki E, Figueria S, Haghighi K, Rubinstein J, Lorenz J, Kranias EG. Constitutive phosphorylation of inhibitor-1 at Ser67 and Thr75 depresses calcium cycling in cardiomyocytes and leads to remodeling upon aging. Basic Res Cardiol 2012; 107:279. [PMID: 22777184 DOI: 10.1007/s00395-012-0279-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 06/08/2012] [Accepted: 06/25/2012] [Indexed: 12/15/2022]
Abstract
The activity of protein phosphatase-1 (PP1) inhibitor-1 (I-1) is antithetically modulated by the cAMP-protein kinase A (PKA) and Ca(2+)-protein kinase C (PKC) signaling axes. β-adrenergic (β-AR) stimulation results in PKA-phosphorylation of I-1 at threonine 35 (Thr35) and depressed PP1 activity, while PKC phosphorylation at serine 67 (Ser67) and/or Thr75 increases PP1 activity. In heart failure, pThr35 is decreased while pSer67 and pThr75 are elevated. However, the role of Ser67/Thr75 phosphorylation in vivo and its effects on Ca(2+)-cycling are not known. Thus, our aim was to investigate the functional significance of Ser67 and Thr75 phosphorylation in intact hearts. We generated transgenic mice (TG) with cardiac-specific overexpression of constitutively phosphorylated I-1 at Ser67 and Thr75 (S67D/T75D) and evaluated cardiac function. The S67D/T75D cardiomyocytes exhibited significantly depressed Ca(2+)-kinetics and contractile parameters, compared with wild-type (WT) cells. The decreased Ca(2+)-cycling was associated with a 27 % increase in PP1 activity, no alterations in PP2 activity and impaired phosphorylation of myosin-binding protein-C (MyBPC). Upon aging, there was cardiac remodeling associated with increases in systolic and diastolic left ventricular internal diameter dimensions (at 16 months), compared with WTs. The results indicate that phosphorylation of I-1 at Ser67 and Thr75 is associated with increased PP1 activity and depressed cardiomyocyte Ca(2+)-cycling, which manifests in geometrical alterations over the long term. Thus, hyperphosphorylation of these sites in failing hearts may contribute to deteriorative remodeling.
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Affiliation(s)
- Stela Florea
- Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
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15
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Cheng G, Kasiganesan H, Baicu CF, Wallenborn JG, Kuppuswamy D, Cooper G. Cytoskeletal role in protection of the failing heart by β-adrenergic blockade. Am J Physiol Heart Circ Physiol 2011; 302:H675-87. [PMID: 22081703 DOI: 10.1152/ajpheart.00867.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Formation of a dense microtubule network that impedes cardiac contraction and intracellular transport occurs in severe pressure overload hypertrophy. This process is highly dynamic, since microtubule depolymerization causes striking improvement in contractile function. A molecular etiology for this cytoskeletal alteration has been defined in terms of type 1 and type 2A phosphatase-dependent site-specific dephosphorylation of the predominant myocardial microtubule-associated protein (MAP)4, which then decorates and stabilizes microtubules. This persistent phosphatase activation is dependent upon ongoing upstream activity of p21-activated kinase-1, or Pak1. Because cardiac β-adrenergic activity is markedly and continuously increased in decompensated hypertrophy, and because β-adrenergic activation of cardiac Pak1 and phosphatases has been demonstrated, we asked here whether the highly maladaptive cardiac microtubule phenotype seen in pathological hypertrophy is based on β-adrenergic overdrive and thus could be reversed by β-adrenergic blockade. The data in this study, which were designed to answer this question, show that such is the case; that is, β(1)- (but not β(2)-) adrenergic input activates this pathway, which consists of Pak1 activation, increased phosphatase activity, MAP4 dephosphorylation, and thus the stabilization of a dense microtubule network. These data were gathered in a feline model of severe right ventricular (RV) pressure overload hypertrophy in response to tight pulmonary artery banding (PAB) in which a stable, twofold increase in RV mass is reached by 2 wk after pressure overloading. After 2 wk of hypertrophy induction, these PAB cats during the following 2 wk either had no further treatment or had β-adrenergic blockade. The pathological microtubule phenotype and the severe RV cellular contractile dysfunction otherwise seen in this model of RV hypertrophy (PAB No Treatment) was reversed in the treated (PAB β-Blockade) cats. Thus these data provide both a specific etiology and a specific remedy for the abnormal microtubule network found in some forms of pathological cardiac hypertrophy.
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Affiliation(s)
- Guangmao Cheng
- Gazes Cardiac Research Institute, PO Box 250773, Medical Univ. of South Carolina, 114 Doughty St., Charleston, SC 29403, USA
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16
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Shintani-Ishida K, Yoshida KI. Ischemia induces phospholamban dephosphorylation via activation of calcineurin, PKC-α, and protein phosphatase 1, thereby inducing calcium overload in reperfusion. Biochim Biophys Acta Mol Basis Dis 2011; 1812:743-51. [DOI: 10.1016/j.bbadis.2011.03.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 02/23/2011] [Accepted: 03/21/2011] [Indexed: 11/30/2022]
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17
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Singh A, Redden JM, Kapiloff MS, Dodge-Kafka KL. The large isoforms of A-kinase anchoring protein 18 mediate the phosphorylation of inhibitor-1 by protein kinase A and the inhibition of protein phosphatase 1 activity. Mol Pharmacol 2010; 79:533-40. [PMID: 21149637 DOI: 10.1124/mol.110.065425] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inhibitor-1 (I-1) is phosphorylated on threonine residue 35 (Thr35) by the cAMP-dependent protein kinase (PKA), inducing the potent inhibition of the serine-threonine-specific protein phosphatase 1 (PP1). We now report that the formation of a signaling complex containing PKA and I-1 by the A-kinase anchoring protein 18 (AKAP18) facilitates this regulation in cells. AKAP18 directly bound I-1, and AKAP18/I-1 complexes were isolated from both rat heart extract and transfected heterologous cells. It is noteworthy that prevention of PKA binding to the AKAP18 scaffold decreased I-1 phosphorylation by 48% in cells. Moreover, the I-1 target PP1 was also associated with AKAP18 complexes. The cAMP-mediated inhibition of phosphatase activity was contingent on PKA binding to the scaffold. These observations reveal an additional level of complexity in PP1 regulation because of its association with AKAP18 multimolecular signaling complexes and suggest that targeting of AKAP18 complexes may be an alternative method to alter phosphatase activity and modulate specific substrate dephosphorylation.
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Affiliation(s)
- Arpita Singh
- Pat and Jim Calhoun Center for Cardiology, University of Connecticut Health Center, Farmington, CT 06032, USA
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18
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Wang M, Zhang WB, Zhu JH, Fu GS, Zhou BQ. Breviscapine ameliorates cardiac dysfunction and regulates the myocardial Ca(2+)-cycling proteins in streptozotocin-induced diabetic rats. Acta Diabetol 2010; 47 Suppl 1:209-18. [PMID: 19882101 DOI: 10.1007/s00592-009-0164-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 10/08/2009] [Indexed: 01/11/2023]
Abstract
To investigate the influence of breviscapine on the cardiac structure and function in diabetic cardiomyopathy rats as well as the expression of protein kinase C (PKC) and Ca(2+)-cycling proteins expression. Diabetes was induced in male Sprague-Dawley rats by a single intraperitoneal injection of streptozotocin and the control rats were injected with saline. After the induction of diabetes for 4 weeks, the animals were divided into different groups: (1) normal rats as control; (2) diabetic rats; (3) diabetic rats with administration of breviscapine (10 or 25 mg kg(-1) day(-2)). After treatment with breviscapine for 6 weeks, the invasive cardiac function and echocardiographic parameters were measured, and heart tissue was obtained for electron microscope study. The expression of protein kinase C (PKC) and calcium handling regulators, such as protein phosphatase inhibitor-1 (PPI-1), phospholamban (PLB) and Ca(2+)-ATPase (SERCA-2), ryanodine receptor (RyR) were detected by western blot or RT-PCR. The activity of SERCA-2 was measured using Ca(2+)-ATPase kit. Diabetic rats showed impaired cardiac structure and function compared with control rats. The expression of PKC, PLB increased significantly, while the PPI-1, SERCA-2 and RyR expression decreased. Treatment with breviscapine could reverse the cardiac dysfunction and structure changes in diabetic cardiomyopathy rats, and decrease the expression of PKC and PLB, as well as increase the expression of PPI-1, SERCA-2 and RyR. The protective effect of breviscapine was dose related. This study showed that breviscapine could regulate the expression of PKC, PPI-1, PLB and SERCA-2 and have protective effect on diabetic cardiomyopathy.
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Affiliation(s)
- Min Wang
- Key Laboratory of Biotherapy of Zhejiang Province, Department of Cardiovascular Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, 3 East Qingchun Road, 310016, Hangzhou, Zhejiang Province, People's Republic of China.
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19
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Cheng G, Takahashi M, Shunmugavel A, Wallenborn JG, DePaoli-Roach AA, Gergs U, Neumann J, Kuppuswamy D, Menick DR, Cooper G. Basis for MAP4 dephosphorylation-related microtubule network densification in pressure overload cardiac hypertrophy. J Biol Chem 2010; 285:38125-40. [PMID: 20889984 DOI: 10.1074/jbc.m110.148650] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Increased activity of Ser/Thr protein phosphatases types 1 (PP1) and 2A (PP2A) during maladaptive cardiac hypertrophy contributes to cardiac dysfunction and eventual failure, partly through effects on calcium metabolism. A second maladaptive feature of pressure overload cardiac hypertrophy that instead leads to heart failure by interfering with cardiac contraction and intracellular transport is a dense microtubule network stabilized by decoration with microtubule-associated protein 4 (MAP4). In an earlier study we showed that the major determinant of MAP4-microtubule affinity, and thus microtubule network density and stability, is site-specific MAP4 dephosphorylation at Ser-924 and to a lesser extent at Ser-1056; this was found to be prominent in hypertrophied myocardium. Therefore, in seeking the etiology of this MAP4 dephosphorylation, we looked here at PP2A and PP1, as well as the upstream p21-activated kinase 1, in maladaptive pressure overload cardiac hypertrophy. The activity of each was increased persistently during maladaptive hypertrophy, and overexpression of PP2A or PP1 in normal hearts reproduced both the microtubule network phenotype and the dephosphorylation of MAP4 Ser-924 and Ser-1056 seen in hypertrophy. Given the major microtubule-based abnormalities of contractile and transport function in maladaptive hypertrophy, these findings constitute a second important mechanism for phosphatase-dependent pathology in the hypertrophied and failing heart.
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Affiliation(s)
- Guangmao Cheng
- Gazes Cardiac Research Institute, Cardiology Division, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29403, USA
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20
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Nicolaou P, Hajjar RJ, Kranias EG. Role of protein phosphatase-1 inhibitor-1 in cardiac physiology and pathophysiology. J Mol Cell Cardiol 2009; 47:365-71. [PMID: 19481088 DOI: 10.1016/j.yjmcc.2009.05.010] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 05/14/2009] [Accepted: 05/20/2009] [Indexed: 10/20/2022]
Abstract
The type 1 protein phosphatase (PP1) is a critical negative regulator of Ca(2+) cycling and contractility in the cardiomyocyte. In particular, it mediates restoration of cardiac function to basal levels, after beta-adrenergic stimulation, by dephosphorylating key phospho-proteins. PP1 is a holoenzyme comprised of its catalytic and auxiliary subunits. These regulatory proteins dictate PP1's subcellular localization, substrate specificity and activity. Amongst them, inhibitor-1 is of particular importance since it has been implicated as an integrator of multiple neurohormonal pathways, which finely regulate PP1 activity, at the level of the sarcoplasmic reticulum (SR). In fact, perturbations in the regulation of PP1 by inhibitor-1 have been implicated in the pathogenesis of heart failure, suggesting that inhibitor-1-based therapeutic interventions may ameliorate cardiac dysfunction and remodeling in the failing heart. This review will discuss the current views on the role of inhibitor-1 in cardiac physiology, its possible contribution to cardiac disease and its potential as a novel therapeutic strategy.
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Affiliation(s)
- Persoulla Nicolaou
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0575, USA
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21
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Nicolaou P, Knöll R, Haghighi K, Fan GC, Dorn GW, Hasenfub G, Kranias EG. Human mutation in the anti-apoptotic heat shock protein 20 abrogates its cardioprotective effects. J Biol Chem 2008; 283:33465-71. [PMID: 18790732 DOI: 10.1074/jbc.m802307200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The small heat shock protein Hsp20 protects cardiomyocytes against apoptosis, and phosphorylation at its Ser16 site enhances its cardioprotection. To determine whether genetic variants exist in human Hsp20, which may modify these beneficial effects, we sequenced the coding region of the Hsp20 gene in 1347 patients suffering from dilated cardiomyopathy and 744 subjects with no heart disease. We identified a C59T substitution in the human Hsp20 gene in one patient and three individuals without heart disease. All subjects were heterozygous for this mutation, which changes a fully conserved proline residue into leucine at position 20 (P20L), resulting in secondary structural alterations. To examine the potential functional significance of the P20L-Hsp20 human variant, adult rat cardiomyocytes were infected with Ad.GFP (where Ad is adenovirus and GFP is green fluorescent protein), Ad.WT-Hsp20 (where WT is wild-type), and Ad.P20L-Hsp20 and subjected to simulated ischemia/reperfusion injury. Expression of WT-Hsp20 resulted in significant attenuation of apoptosis compared with the GFP control. However, the P20L-Hsp20 mutant showed no protection against apoptosis, assessed by Hoechst staining and DNA fragmentation. The loss of cardioprotection by the mutant Hsp20 was associated with its diminished phosphorylation at Ser16 compared with WT-Hsp20. Furthermore, maximal stimulation of cardiomyocytes with isoproterenol or protein kinase A-mediated phosphorylation in vitro confirmed the impaired ability of the mutant Hsp20 to become phosphorylated at Ser16. In conclusion, we have identified a P20L substitution in human Hsp20, which is associated with diminished phosphorylation at Ser16 and complete abrogation of the Hsp20 cardioprotective effects which may adversely affect the ability of human carriers to cope with cellular stress.
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Affiliation(s)
- Persoulla Nicolaou
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0575, USA
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22
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Brüchert N, Mavila N, Boknik P, Baba HA, Fabritz L, Gergs U, Kirchhefer U, Kirchhof P, Matus M, Schmitz W, DePaoli-Roach AA, Neumann J. Inhibitor-2 prevents protein phosphatase 1-induced cardiac hypertrophy and mortality. Am J Physiol Heart Circ Physiol 2008; 295:H1539-46. [PMID: 18689497 DOI: 10.1152/ajpheart.00515.2008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac-specific overexpression of the catalytic subunit of protein phosphatase type 1 (PP1) in mice results in hypertrophy, depressed contractility, propensity to heart failure, and premature death. To further address the role of PP1 in heart function, PP1 mice were crossed with mice that overexpress a functional COOH-terminally truncated form of PP1 inhibitor-2 (I-2(140)). Protein phosphatase activity was increased in PP1 mice but was normalized in double transgenic (DT) mice. The maximal rates of contraction (+dP/dt) and of relaxation (-dP/dt) were reduced in catheterized PP1 mice but normalized in DT mice. Similar contractile abnormalities were observed in isolated, perfused work-performing hearts and in whole animals by means of echocardiography. The increased absolute and relative heart weights observed in PP1 mice were normalized in DT mice. Histological analyses indicated that PP1 mice had significant cardiac fibrosis, which was absent in DT mice. Furthermore, PP1 mice exhibited an age-dependent increase in mortality, which was abrogated in DT mice. These results indicate that I-2 overexpression prevents the detrimental effects of PP1 overexpression in the heart and further underscore the fundamental role of PP1 in cardiac function. Therefore, PP1 inhibitors such as I-2 could offer new therapeutic options to ameliorate the deleterious effects of heart failure.
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Affiliation(s)
- Nicole Brüchert
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität, Münster, Germany
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23
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Ikeda Y, Hoshijima M, Chien KR. Toward biologically targeted therapy of calcium cycling defects in heart failure. Physiology (Bethesda) 2008; 23:6-16. [PMID: 18268360 DOI: 10.1152/physiol.00033.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A growing body of evidence indicates that heart failure progression is tightly associated with dysregulation of phosphorylation of Ca2+ regulators localized in the sub-cellular microdomain of the sarcoplasmic reticulum. Chemical or genetic correction of abnormalities in cardiac phosphorylation cascades is emerging as a potential target in the treatment of heart failure. Here, we review how specific kinases and phosphatases finely tune Ca2+ cycling and regulate excitation-contraction (E-C) coupling in cardiomyocytes.
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Affiliation(s)
- Yasuhiro Ikeda
- Department of Molecular Cardiovascular Biology, Yamaguchi University School of Medicine, Ube, Japan.
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24
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El-Armouche A, Singh J, Naito H, Wittköpper K, Didié M, Laatsch A, Zimmermann WH, Eschenhagen T. Adenovirus-delivered short hairpin RNA targeting PKCalpha improves contractile function in reconstituted heart tissue. J Mol Cell Cardiol 2007; 43:371-6. [PMID: 17628588 DOI: 10.1016/j.yjmcc.2007.05.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Revised: 04/23/2007] [Accepted: 05/29/2007] [Indexed: 12/13/2022]
Abstract
PKCalpha has been shown to be a negative regulator of contractility and PKCalpha gene deletion in mice protected against heart failure. Small interfering (si)RNAs mediate gene silencing by RNA interference (RNAi) and may be used to knockdown PKCalpha in cardiomyocytes. However, transfection efficiencies of (si)RNAs by lipofection tend to be low in primary cells. To address this limitation, we developed an adenoviral vector (AV) driving short hairpin (sh)RNAs against PKCalpha (Ad-shPKCalpha) and evaluated its potential to silence PKCalpha in neonatal rat cardiac myocytes and in engineered heart tissues (EHTs), which resemble functional myocardium in vitro. A nonsense encoding AV (Ad-shNS) served as control. Quantitative PCR and Western blotting showed 90% lower PKCalpha-mRNA and 50% lower PKCalpha protein in Ad-shPKCalpha-infected cells. EHTs were infected with Ad-shPKCalpha on day 11 and subjected to isometric force measurements in organ baths 4 days later. Mean twitch tension was >50% higher in Ad-shPKCalpha compared to Ad-shNS-infected EHTs, under basal and Ca(2+)- or isoprenaline-stimulated conditions. Twitch tension negatively correlated with PKCalpha mRNA levels. In summary, AV-delivered shRNA mediated highly efficient PKCalpha knockdown in cardiac myocytes and improved contractility in EHTs. The data support a role of PKCalpha as a negative regulator of myocardial contractility and demonstrate that EHTs in conjunction with AV-delivered shRNA are a useful model for target validation.
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Affiliation(s)
- Ali El-Armouche
- Institute of Experimental and Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20246, Germany.
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Rodriguez P, Mitton B, Nicolaou P, Chen G, Kranias EG. Phosphorylation of human inhibitor-1 at Ser67 and/or Thr75 attenuates stimulatory effects of protein kinase A signaling in cardiac myocytes. Am J Physiol Heart Circ Physiol 2007; 293:H762-9. [PMID: 17416610 DOI: 10.1152/ajpheart.00104.2007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The depressed function of failing hearts has been partially attributed to increased protein phosphatase-1 through its impaired regulation by inhibitor-1. Phosphorylation of inhibitor-1 at Thr35 by PKA results in potent inhibition of protein phosphatase-1 activity, while phosphorylation at Ser67 or Thr75 by PKC attenuates the inhibitory activity. To examine the functional role of dual-site (Ser67, Thr75) phosphorylation of inhibitor-1 by PKC, the constitutively phosphorylated Ser67 (S67D) and/or Thr75 (T75D) human inhibitor-1 forms were expressed in adult cardiomyocytes. Expression of either single or double phosphorylated inhibitor-1 was associated with similar decreases in cardiac contractility, indicating that maximal inhibition can be elicited by each of these sites alone and that their inhibitory effects are not additive. Notably, activation of the cAMP pathway could only partially reverse the depressed contractile parameters. Accordingly, protein phosphatase-1 activity remained elevated, phosphorylation of phospholamban at Ser16 was decreased, and the EC(50) values of the sarcoplasmic reticulum calcium transport system were higher compared with controls. Thus phosphorylation of Ser67 and/or Thr75 in inhibitor-1 may mitigate the stimulatory effects of the cAMP pathway, resulting in compromised cardiac function.
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Affiliation(s)
- Patricia Rodriguez
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267-0575, USA
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