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Blaustein MP, Hamlyn JM. Sensational site: the sodium pump ouabain-binding site and its ligands. Am J Physiol Cell Physiol 2024; 326:C1120-C1177. [PMID: 38223926 PMCID: PMC11193536 DOI: 10.1152/ajpcell.00273.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/22/2023] [Accepted: 01/10/2024] [Indexed: 01/16/2024]
Abstract
Cardiotonic steroids (CTS), used by certain insects, toads, and rats for protection from predators, became, thanks to Withering's trailblazing 1785 monograph, the mainstay of heart failure (HF) therapy. In the 1950s and 1960s, we learned that the CTS receptor was part of the sodium pump (NKA) and that the Na+/Ca2+ exchanger was critical for the acute cardiotonic effect of digoxin- and ouabain-related CTS. This "settled" view was upended by seven revolutionary observations. First, subnanomolar ouabain sometimes stimulates NKA while higher concentrations are invariably inhibitory. Second, endogenous ouabain (EO) was discovered in the human circulation. Third, in the DIG clinical trial, digoxin only marginally improved outcomes in patients with HF. Fourth, cloning of NKA in 1985 revealed multiple NKA α and β subunit isoforms that, in the rodent, differ in their sensitivities to CTS. Fifth, the NKA is a cation pump and a hormone receptor/signal transducer. EO binding to NKA activates, in a ligand- and cell-specific manner, several protein kinase and Ca2+-dependent signaling cascades that have widespread physiological effects and can contribute to hypertension and HF pathogenesis. Sixth, all CTS are not equivalent, e.g., ouabain induces hypertension in rodents while digoxin is antihypertensinogenic ("biased signaling"). Seventh, most common rodent hypertension models require a highly ouabain-sensitive α2 NKA and the elevated blood pressure is alleviated by EO immunoneutralization. These numerous phenomena are enabled by NKA's intricate structure. We have just begun to understand the endocrine role of the endogenous ligands and the broad impact of the ouabain-binding site on physiology and pathophysiology.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
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2
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Huang S, Dong W, Lin X, Xu K, Li K, Xiong S, Wang Z, Nie X, Bian JS. Disruption of the Na +/K +-ATPase-purinergic P2X7 receptor complex in microglia promotes stress-induced anxiety. Immunity 2024; 57:495-512.e11. [PMID: 38395698 DOI: 10.1016/j.immuni.2024.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 11/15/2023] [Accepted: 01/29/2024] [Indexed: 02/25/2024]
Abstract
Na+/K+-ATPase (NKA) plays an important role in the central nervous system. However, little is known about its function in the microglia. Here, we found that NKAα1 forms a complex with the purinergic P2X7 receptor (P2X7R), an adenosine 5'-triphosphate (ATP)-gated ion channel, under physiological conditions. Chronic stress or treatment with lipopolysaccharide plus ATP decreased the membrane expression of NKAα1 in microglia, facilitated P2X7R function, and promoted microglia inflammatory activation via activation of the NLRP3 inflammasome. Accordingly, global deletion or conditional deletion of NKAα1 in microglia under chronic stress-induced aggravated anxiety-like behavior and neuronal hyperexcitability. DR5-12D, a monoclonal antibody that stabilizes membrane NKAα1, improved stress-induced anxiety-like behavior and ameliorated neuronal hyperexcitability and neurogenesis deficits in the ventral hippocampus of mice. Our results reveal that NKAα1 limits microglia inflammation and may provide a target for the treatment of stress-related neuroinflammation and diseases.
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Affiliation(s)
- Songqiang Huang
- Department of Pharmacology, Joint Laboratory of Guangdong-Hong Kong Universities for Vascular Homeostasis and Diseases, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Wanting Dong
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Xiaoqian Lin
- Department of Pharmacology, Joint Laboratory of Guangdong-Hong Kong Universities for Vascular Homeostasis and Diseases, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Kangtai Xu
- Department of Neuroscience, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Kun Li
- Department of Neuroscience, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Siping Xiong
- Department of Pathology, the Eighth Affiliated Hospital of Sun Yat-Sen University, Shenzhen 518033, Guangdong, China
| | - Zilong Wang
- Department of Neuroscience, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Xiaowei Nie
- Key Laboratory of Shenzhen Respiratory Disease, Shenzhen Institute of Respiratory Disease, Shenzhen People's Hospital (the First Affiliated Hospital of Southern University of Science and Technology, the Second Clinical Medical College of Jinan University), Shenzhen 518020, Guangdong, China.
| | - Jin-Song Bian
- Department of Pharmacology, Joint Laboratory of Guangdong-Hong Kong Universities for Vascular Homeostasis and Diseases, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China.
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3
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Yan X, Li M, Lan P, Xun M, Zhang Y, Shi J, Wang R, Zheng J. Regulation of Na+-K+-ATPase leads to disturbances of isoproterenol-induced cardiac dysfunction via interference of Ca2+-dependent cardiac metabolism. Clin Sci (Lond) 2024; 138:23-42. [PMID: 38060817 DOI: 10.1042/cs20231039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 01/06/2024]
Abstract
Reductions in Na+-K+-ATPase (NKA) activity and expression are often observed in the progress of various reason-induced heart failure (HF). However, NKA α1 mutation or knockdown cannot cause spontaneous heart disease. Whether the abnormal NKA α1 directly contributes to HF pathogenesis remains unknown. Here, we challenge NKA α1+/- mice with isoproterenol to evaluate the role of NKA α1 haploinsufficiency in isoproterenol (ISO)-induced cardiac dysfunction. Genetic knockdown of NKA α1 accelerated ISO-induced cardiac cell hypertrophy, heart fibrosis, and dysfunction. Further studies revealed decreased Krebs cycle, fatty acid oxidation, and mitochondrial OXPHOS in the hearts of NKA α1+/- mice challenged with ISO. In ISO-treated conditions, inhibition of NKA elevated cytosolic Na+, further reduced mitochondrial Ca2+ via mNCE, and then finally down-regulated cardiac cell energy metabolism. In addition, a supplement of DRm217 alleviated ISO-induced heart dysfunction, mitigated cardiac remodeling, and improved cytosolic Na+ and Ca2+ elevation and mitochondrial Ca2+ depression in the NKA α1+/- mouse model. The findings suggest that targeting NKA and mitochondria Ca2+ could be a promising strategy in the treatment of heart disease.
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Affiliation(s)
- Xiaofei Yan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an 710061, China
| | - Meihe Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an 710061, China
- Hospital of Nephrology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Ping Lan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an 710061, China
- Hospital of Nephrology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Meng Xun
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an 710061, China
| | - Ying Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an 710061, China
- Hospital of Nephrology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Jinghui Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an 710061, China
- Department of Clinical laboratory in Xi'an Fourth Hospital, Xi'an 710004, China
| | - Ruijia Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an 710061, China
| | - Jin Zheng
- Hospital of Nephrology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
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Waknitz M, Berg Luecke L, Mesidor R, Wojtkiewicz M, Castro C, Gundry RL. The GENTIL Method for Isolation of Human Adult Cardiomyocytes from Cryopreserved Tissue for Proteomic Analyses. Methods Mol Biol 2024; 2735:145-167. [PMID: 38038848 PMCID: PMC11232436 DOI: 10.1007/978-1-0716-3527-8_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Heart failure is a serious clinical and economic health care problem, and its clinical progression is linked to pathological cardiac remodeling. Due to the heterogeneity of heart failure, lack of animal models to accurately represent advanced heart failure, and limited access to fresh human cardiac tissue, little is known regarding cell-type-specific mechanisms and context-specific functions of cardiomyocytes during disease development processes. While mass spectrometry has been increasingly applied to unravel changes in the proteome associated with cardiovascular physiology and disease, most studies have used homogenized tissue. Therefore, new studies using isolated cardiomyocytes are necessary to gain a better understanding of the intricate cell-type-specific molecular mechanisms underlying the pathophysiology of heart failure. This chapter describes the GENTIL method, which incorporates recent technological developments in sample handling, for isolation of cardiomyocytes from cryopreserved human cardiac tissues for use in proteomic analyses.
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Affiliation(s)
- Michelle Waknitz
- CardiOmics Program, Center for Heart and Vascular Research; Division of Cardiovascular Medicine; and Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Linda Berg Luecke
- CardiOmics Program, Center for Heart and Vascular Research; Division of Cardiovascular Medicine; and Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Roneldine Mesidor
- CardiOmics Program, Center for Heart and Vascular Research; Division of Cardiovascular Medicine; and Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Melinda Wojtkiewicz
- CardiOmics Program, Center for Heart and Vascular Research; Division of Cardiovascular Medicine; and Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Chase Castro
- CardiOmics Program, Center for Heart and Vascular Research; Division of Cardiovascular Medicine; and Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Rebekah L Gundry
- CardiOmics Program, Center for Heart and Vascular Research; Division of Cardiovascular Medicine; and Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA.
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Cai L, Pessoa MT, Gao Y, Strause S, Banerjee M, Tian J, Xie Z, Pierre SV. The Na/K-ATPase α1/Src Signaling Axis Regulates Mitochondrial Metabolic Function and Redox Signaling in Human iPSC-Derived Cardiomyocytes. Biomedicines 2023; 11:3207. [PMID: 38137428 PMCID: PMC10740578 DOI: 10.3390/biomedicines11123207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/15/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
Na/K-ATPase (NKA)-mediated regulation of Src kinase, which involves defined amino acid sequences of the NKA α1 polypeptide, has emerged as a novel regulatory mechanism of mitochondrial function in metazoans. Mitochondrial metabolism ensures adequate myocardial performance and adaptation to physiological demand. It is also a critical cellular determinant of cardiac repair and remodeling. To assess the impact of the proposed NKA/Src regulatory axis on cardiac mitochondrial metabolic function, we used a gene targeting approach in human cardiac myocytes. Human induced pluripotent stem cells (hiPSC) expressing an Src-signaling null mutant (A420P) form of the NKA α1 polypeptide were generated using CRISPR/Cas9-mediated genome editing. Total cellular Na/K-ATPase activity remained unchanged in A420P compared to the wild type (WT) hiPSC, but baseline phosphorylation levels of Src and ERK1/2 were drastically reduced. Both WT and A420P mutant hiPSC readily differentiated into cardiac myocytes (iCM), as evidenced by marker gene expression, spontaneous cell contraction, and subcellular striations. Total NKA α1-3 protein expression was comparable in WT and A420P iCM. However, live cell metabolism assessed functionally by Seahorse extracellular flux analysis revealed significant reductions in both basal and maximal rates of mitochondrial respiration, spare respiratory capacity, ATP production, and coupling efficiency. A significant reduction in ROS production was detected by fluorescence imaging in live cells, and confirmed by decreased cellular protein carbonylation levels in A420P iCM. Taken together, these data provide genetic evidence for a role of NKA α1/Src in the tonic stimulation of basal mitochondrial metabolism and ROS production in human cardiac myocytes. This signaling axis in cardiac myocytes may provide a new approach to counteract mitochondrial dysfunction in cardiometabolic diseases.
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Affiliation(s)
- Liquan Cai
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Marco T. Pessoa
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Yingnyu Gao
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Sidney Strause
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Moumita Banerjee
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
- Department of Surgery, University of Kentucky, Lexington, KY 40536, USA
| | - Jiang Tian
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
- Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA
| | - Zijian Xie
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Sandrine V. Pierre
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
- Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA
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Karbowski M, Boyman L, Garber L, Joca HC, Verhoeven N, Coleman AK, Ward CW, Lederer WJ, Greiser M. Na + /K + ATPase-Ca v 1.2 nanodomain differentially regulates intracellular [Na + ], [Ca 2+ ] and local adrenergic signaling in cardiac myocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.31.553598. [PMID: 37693446 PMCID: PMC10491240 DOI: 10.1101/2023.08.31.553598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Background The intracellular Na + concentration ([Na + ] i ) is a crucial but understudied regulator of cardiac myocyte function. The Na + /K + ATPase (NKA) controls the steady-state [Na + ] i and thereby determines the set-point for intracellular Ca 2+ . Here, we investigate the nanoscopic organization and local adrenergic regulation of the NKA macromolecular complex and how it differentially regulates the intracellular Na + and Ca 2+ homeostases in atrial and ventricular myocytes. Methods Multicolor STORM super-resolution microscopy, Western Blot analyses, and in vivo examination of adrenergic regulation are employed to examine the organization and function of Na + nanodomains in cardiac myocytes. Quantitative fluorescence microscopy at high spatiotemporal resolution is used in conjunction with cellular electrophysiology to investigate intracellular Na + homeostasis in atrial and ventricular myocytes. Results The NKAα1 (NKAα1) and the L-type Ca 2+ -channel (Ca v 1.2) form a nanodomain with a center-to center distance of ∼65 nm in both ventricular and atrial myocytes. NKAα1 protein expression levels are ∼3 fold higher in atria compared to ventricle. 100% higher atrial I NKA , produced by large NKA "superclusters", underlies the substantially lower Na + concentration in atrial myocytes compared to the benchmark values set in ventricular myocytes. The NKA's regulatory protein phospholemman (PLM) has similar expression levels across atria and ventricle resulting in a much lower PLM/NKAα1 ratio for atrial compared to ventricular tissue. In addition, a huge PLM phosphorylation reserve in atrial tissue produces a high ß-adrenergic sensitivity of I NKA in atrial myocytes. ß-adrenergic regulation of I NKA is locally mediated in the NKAα1-Ca v 1.2 nanodomain via A-kinase anchoring proteins. Conclusions NKAα1, Ca v 1.2 and their accessory proteins form a structural and regulatory nanodomain at the cardiac dyad. The tissue-specific composition and local adrenergic regulation of this "signaling cloud" is a main regulator of the distinct global intracellular Na + and Ca 2+ concentrations in atrial and ventricular myocytes.
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Baloglu E. Hypoxic Stress-Dependent Regulation of Na,K-ATPase in Ischemic Heart Disease. Int J Mol Sci 2023; 24:ijms24097855. [PMID: 37175562 PMCID: PMC10177966 DOI: 10.3390/ijms24097855] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
In cardiomyocytes, regular activity of the Na,K-ATPase (NKA) and its Na/K pump activity is essential for maintaining ion gradients, excitability, propagation of action potentials, electro-mechanical coupling, trans-membrane Na+ and Ca2+ gradients and, thus, contractility. The activity of NKA is impaired in ischemic heart disease and heart failure, which has been attributed to decreased expression of the NKA subunits. Decreased NKA activity leads to intracellular Na+ and Ca2+ overload, diastolic dysfunction and arrhythmias. One signal likely related to these events is hypoxia, where hypoxia-inducible factors (HIF) play a critical role in the adaptation of cells to low oxygen tension. HIF activity increases in ischemic heart, hypertension, heart failure and cardiac fibrosis; thus, it might contribute to the impaired function of NKA. This review will mainly focus on the regulation of NKA in ischemic heart disease in the context of stressed myocardium and the hypoxia-HIF axis and argue on possible consequences of treatment.
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Affiliation(s)
- Emel Baloglu
- Department of Medical Pharmacology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Turkey
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Rajanathan R, Riera CVI, Pedersen TM, Staehr C, Bouzinova EV, Nyengaard JR, Thomsen MB, Bøtker HE, Matchkov VV. Hypercontractile Cardiac Phenotype in Mice with Migraine-Associated Mutation in the Na +,K +-ATPase α 2-Isoform. Cells 2023; 12:cells12081108. [PMID: 37190017 DOI: 10.3390/cells12081108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/03/2023] [Accepted: 04/05/2023] [Indexed: 05/17/2023] Open
Abstract
Two α-isoforms of the Na+,K+-ATPase (α1 and α2) are expressed in the cardiovascular system, and it is unclear which isoform is the preferential regulator of contractility. Mice heterozygous for the familial hemiplegic migraine type 2 (FHM2) associated mutation in the α2-isoform (G301R; α2+/G301R mice) have decreased expression of cardiac α2-isoform but elevated expression of the α1-isoform. We aimed to investigate the contribution of the α2-isoform function to the cardiac phenotype of α2+/G301R hearts. We hypothesized that α2+/G301R hearts exhibit greater contractility due to reduced expression of cardiac α2-isoform. Variables for contractility and relaxation of isolated hearts were assessed in the Langendorff system without and in the presence of ouabain (1 µM). Atrial pacing was performed to investigate rate-dependent changes. The α2+/G301R hearts displayed greater contractility than WT hearts during sinus rhythm, which was rate-dependent. The inotropic effect of ouabain was more augmented in α2+/G301R hearts than in WT hearts during sinus rhythm and atrial pacing. In conclusion, cardiac contractility was greater in α2+/G301R hearts than in WT hearts under resting conditions. The inotropic effect of ouabain was rate-independent and enhanced in α2+/G301R hearts, which was associated with increased systolic work.
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Affiliation(s)
| | - Clàudia Vilaseca I Riera
- Department of Basic Science, School of Medicine and Health Sciences, International University of Catalonia, 08195 Barcelona, Spain
| | | | - Christian Staehr
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | | | - Jens Randel Nyengaard
- Department of Clinical Medicine, Core Center for Molecular Morphology, Section for Stereology and Microscopy, Aarhus University, 8000 Aarhus, Denmark
- Department of Pathology, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Morten B Thomsen
- Biomedical Sciences, University of Copenhagen, 1168 Copenhagen, Denmark
| | - Hans Erik Bøtker
- Department of Cardiology, Aarhus University Hospital, 8200 Aarhus, Denmark
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Asfaw TN, Bondarenko VE. A compartmentalized mathematical model of the β 1- and β 2-adrenergic signaling systems in ventricular myocytes from mouse in heart failure. Am J Physiol Cell Physiol 2023; 324:C263-C291. [PMID: 36468844 DOI: 10.1152/ajpcell.00366.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mouse models of heart failure are extensively used to research human cardiovascular diseases. In particular, one of the most common is the mouse model of heart failure resulting from transverse aortic constriction (TAC). Despite this, there are no comprehensive compartmentalized mathematical models that describe the complex behavior of the action potential, [Ca2+]i transients, and their regulation by β1- and β2-adrenergic signaling systems in failing mouse myocytes. In this paper, we develop a novel compartmentalized mathematical model of failing mouse ventricular myocytes after TAC procedure. The model describes well the cell geometry, action potentials, [Ca2+]i transients, and β1- and β2-adrenergic signaling in the failing cells. Simulation results obtained with the failing cell model are compared with those from the normal ventricular myocytes. Exploration of the model reveals the sarcoplasmic reticulum Ca2+ load mechanisms in failing ventricular myocytes. We also show a larger susceptibility of the failing myocytes to early and delayed afterdepolarizations and to a proarrhythmic behavior of Ca2+ dynamics upon stimulation with isoproterenol. The mechanisms of the proarrhythmic behavior suppression are investigated and sensitivity analysis is performed. The developed model can explain the existing experimental data on failing mouse ventricular myocytes and make experimentally testable predictions of a failing myocyte's behavior.
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Affiliation(s)
- Tesfaye Negash Asfaw
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia
| | - Vladimir E Bondarenko
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia.,Neuroscience Institute, Georgia State University, Atlanta, Georgia
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10
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Rajanathan R, Pedersen TM, Guldbrandsen HO, Olesen LF, Thomsen MB, Bøtker HE, Matchkov VV. Augmented Ouabain-Induced Vascular Response Reduces Cardiac Efficiency in Mice with Migraine-Associated Mutation in the Na +, K +-ATPase α 2-Isoform. Biomedicines 2023; 11:biomedicines11020344. [PMID: 36830881 PMCID: PMC9953359 DOI: 10.3390/biomedicines11020344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/22/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023] Open
Abstract
Heterozygous mice (α2+/G301R mice) for the migraine-associated mutation (G301R) in the Na+,K+-ATPase α2-isoform have decreased expression of cardiovascular α2-isoform. The α2+/G301R mice exhibit a pro-contractile vascular phenotype associated with decreased left ventricular ejection fraction. However, the integrated functional cardiovascular consequences of this phenotype remain to be addressed in vivo. We hypothesized that the vascular response to α2-isoform-specific inhibition of the Na+,K+-ATPase by ouabain is augmented in α2+/G301R mice leading to reduced cardiac efficiency. Thus, we aimed to assess the functional contribution of the α2-isoform to in vivo cardiovascular function of wild-type (WT) and α2+/G301R mice. Blood pressure, stroke volume, heart rate, total peripheral resistance, arterial dP/dt, and systolic time intervals were assessed in anesthetized WT and α2+/G301R mice. To address rate-dependent cardiac changes, cardiovascular variables were compared before and after intraperitoneal injection of ouabain (1.5 mg/kg) or vehicle during atrial pacing. The α2+/G301R mice showed an enhanced ouabain-induced increase in total peripheral resistance associated with reduced efficiency of systolic development compared to WT. When the hearts were paced, ouabain reduced stroke volume in α2+/G301R mice. In conclusion, the ouabain-induced vascular response was augmented in α2+/G301R mice with consequent suppression of cardiac function.
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Affiliation(s)
- Rajkumar Rajanathan
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
- Correspondence:
| | | | | | | | - Morten B. Thomsen
- Department of Biomedical Sciences, University of Copenhagen, 1165 Copenhagen, Denmark
| | - Hans Erik Bøtker
- Department of Cardiology, Aarhus University Hospital, 8000 Aarhus, Denmark
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11
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Obradovic M, Sudar-Milovanovic E, Gluvic Z, Banjac K, Rizzo M, Isenovic ER. The Na +/K +-ATPase: A potential therapeutic target in cardiometabolic diseases. Front Endocrinol (Lausanne) 2023; 14:1150171. [PMID: 36926029 PMCID: PMC10011626 DOI: 10.3389/fendo.2023.1150171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 02/14/2023] [Indexed: 03/08/2023] Open
Abstract
Cardiometabolic diseases (CMD) are a direct consequence of modern living and contribute to the development of multisystem diseases such as cardiovascular diseases and diabetes mellitus (DM). CMD has reached epidemic proportions worldwide. A sodium pump (Na+/K+-ATPase) is found in most eukaryotic cells' membrane and controls many essential cellular functions directly or indirectly. This ion transporter and its isoforms are important in the pathogenesis of some pathological processes, including CMD. The structure and function of Na+/K+-ATPase, its expression and distribution in tissues, and its interactions with known ligands such as cardiotonic steroids and other suspected endogenous regulators are discussed in this review. In addition, we reviewed recent literature data related to the involvement of Na+/K+-ATPase activity dysfunction in CMD, focusing on the Na+/K+-ATPase as a potential therapeutic target in CMD.
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Affiliation(s)
- Milan Obradovic
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Emina Sudar-Milovanovic
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Zoran Gluvic
- University Clinical-Hospital Centre Zemun-Belgrade, Clinic of Internal medicine, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Katarina Banjac
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Manfredi Rizzo
- School of Medicine, Promise Department, University of Palermo, Palermo, Italy
- *Correspondence: Manfredi Rizzo,
| | - Esma R. Isenovic
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
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12
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Blaustein MP, Gottlieb SS, Hamlyn JM, Leenen FHH. Whither digitalis? What we can still learn from cardiotonic steroids about heart failure and hypertension. Am J Physiol Heart Circ Physiol 2022; 323:H1281-H1295. [PMID: 36367691 DOI: 10.1152/ajpheart.00362.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cloning of the "Na+ pump" (Na+,K+-ATPase or NKA) and identification of a circulating ligand, endogenous ouabain (EO), a cardiotonic steroid (CTS), triggered seminal discoveries regarding EO and its NKA receptor in cardiovascular function and the pathophysiology of heart failure (HF) and hypertension. Cardiotonic digitalis preparations were a preferred treatment for HF for two centuries, but digoxin was only marginally effective in a large clinical trial (1997). This led to diminished digoxin use. Missing from the trial, however, was any consideration that endogenous CTS might influence digitalis' efficacy. Digoxin, at therapeutic concentrations, acutely inhibits NKA but, remarkably, antagonizes ouabain's action. Prolonged treatment with ouabain, but not digoxin, causes hypertension in rodents; in this model, digoxin lowers blood pressure (BP). Furthermore, NKA-bound ouabain and digoxin modulate different protein kinase signaling pathways and have disparate long-term cardiovascular effects. Reports of "brain ouabain" led to the elucidation of a new, slow neuromodulatory pathway in the brain; locally generated EO and the α2 NKA isoform help regulate sympathetic drive to the heart and vasculature. The roles of EO and α2 NKA have been studied by EO assay, ouabain-resistant mutation of α2 NKA, and immunoneutralization of EO with ouabain-binding Fab fragments. The NKA α2 CTS binding site and its endogenous ligand are required for BP elevation in many common hypertension models and full expression of cardiac remodeling and dysfunction following pressure overload or myocardial infarction. Understanding how endogenous CTS impact hypertension and HF pathophysiology and therapy should foster reconsideration of digoxin's therapeutic utility.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland.,Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Stephen S Gottlieb
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Frans H H Leenen
- Brain and Heart Research Group, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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13
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Skogestad J, Aronsen JM. Regulation of Cardiac Contractility by the Alpha 2 Subunit of the Na+/K+-ATPase. Front Physiol 2022; 13:827334. [PMID: 35812308 PMCID: PMC9258780 DOI: 10.3389/fphys.2022.827334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/16/2022] [Indexed: 11/14/2022] Open
Abstract
Cytosolic Na + concentrations regulate cardiac excitation-contraction coupling and contractility. Inhibition of the Na+/K+-ATPase (NKA) activity increases cardiac contractility by increasing cytosolic Ca2+ levels, as increased cytosolic Na+ levels are coupled to less Ca2+ extrusion and/or increased Ca2+ influx from the Na+/Ca2+-exchanger. NKA consists of one α subunit and one β subunit, with α1 and α2 being the main α isoforms in cardiomyocytes. Substantial evidence suggests that NKAα2 is the primary regulator of cardiac contractility despite being outnumbered by NKAα1 in cardiomyocytes. This review will mainly focus on differential regulation and subcellular localization of the NKAα1 and NKAα2 isoforms, and their relation to the proposed concept of subcellular gradients of Na+ in cardiomyocytes. We will also discuss the potential roles of NKAα2 in mediating cardiac hypertrophy and ventricular arrhythmias.
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Affiliation(s)
- Jonas Skogestad
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Jan Magnus Aronsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
- *Correspondence: Jan Magnus Aronsen,
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14
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Seflova J, Habibi NR, Yap JQ, Cleary SR, Fang X, Kekenes-Huskey PM, Espinoza-Fonseca LM, Bossuyt JB, Robia SL. Fluorescence lifetime imaging microscopy reveals sodium pump dimers in live cells. J Biol Chem 2022; 298:101865. [PMID: 35339486 PMCID: PMC9048134 DOI: 10.1016/j.jbc.2022.101865] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/08/2022] [Accepted: 03/10/2022] [Indexed: 12/30/2022] Open
Abstract
The sodium-potassium ATPase (Na/K-ATPase, NKA) establishes ion gradients that facilitate many physiological functions including action potentials and secondary transport processes. NKA comprises a catalytic subunit (alpha) that interacts closely with an essential subunit (beta) and regulatory transmembrane micropeptides called FXYD proteins. In the heart, a key modulatory partner is the FXYD protein phospholemman (PLM, FXYD1), but the stoichiometry of the alpha-beta-PLM regulatory complex is unknown. Here, we used fluorescence lifetime imaging and spectroscopy to investigate the structure, stoichiometry, and affinity of the NKA-regulatory complex. We observed a concentration-dependent binding of the subunits of NKA-PLM regulatory complex, with avid association of the alpha subunit with the essential beta subunit as well as lower affinity alpha-alpha and alpha-PLM interactions. These data provide the first evidence that, in intact live cells, the regulatory complex is composed of two alpha subunits associated with two beta subunits, decorated with two PLM regulatory subunits. Docking and molecular dynamics (MD) simulations generated a structural model of the complex that is consistent with our experimental observations. We propose that alpha-alpha subunit interactions support conformational coupling of the catalytic subunits, which may enhance NKA turnover rate. These observations provide insight into the pathophysiology of heart failure, wherein low NKA expression may be insufficient to support formation of the complete regulatory complex with the stoichiometry (alpha-beta-PLM)2.
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Affiliation(s)
- Jaroslava Seflova
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA
| | - Nima R Habibi
- Department of Pharmacology, University of California Davis, Davis, California, USA
| | - John Q Yap
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA
| | - Sean R Cleary
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA
| | - Xuan Fang
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA
| | - Peter M Kekenes-Huskey
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA
| | - L Michel Espinoza-Fonseca
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Julie B Bossuyt
- Department of Pharmacology, University of California Davis, Davis, California, USA.
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA.
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15
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Staehr C, Rohde PD, Krarup NT, Ringgaard S, Laustsen C, Johnsen J, Nielsen R, Beck HC, Morth JP, Lykke-Hartmann K, Jespersen NR, Abramochkin D, Nyegaard M, Bøtker HE, Aalkjaer C, Matchkov V. Migraine-Associated Mutation in the Na,K-ATPase Leads to Disturbances in Cardiac Metabolism and Reduced Cardiac Function. J Am Heart Assoc 2022; 11:e021814. [PMID: 35289188 PMCID: PMC9075430 DOI: 10.1161/jaha.121.021814] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Background Mutations in ATP1A2 gene encoding the Na,K‐ATPase α2 isoform are associated with familial hemiplegic migraine type 2. Migraine with aura is a known risk factor for heart disease. The Na,K‐ATPase is important for cardiac function, but its role for heart disease remains unknown. We hypothesized that ATP1A2 is a susceptibility gene for heart disease and aimed to assess the underlying disease mechanism. Methods and Results Mice heterozygous for the familial hemiplegic migraine type 2–associated G301R mutation in the Atp1a2 gene (α2+/G301R mice) and matching wild‐type controls were compared. Reduced expression of the Na,K‐ATPase α2 isoform and increased expression of the α1 isoform were observed in hearts from α2+/G301R mice (Western blot). Left ventricular dilation and reduced ejection fraction were shown in hearts from 8‐month‐old α2+/G301R mice (cardiac magnetic resonance imaging), and this was associated with reduced nocturnal blood pressure (radiotelemetry). Cardiac function and blood pressure of 3‐month‐old α2+/G301R mice were similar to wild‐type mice. Amplified Na,K‐ATPase–dependent Src kinase/Ras/Erk1/2 (p44/42 mitogen‐activated protein kinase) signaling was observed in hearts from 8‐month‐old α2+/G301R mice, and this was associated with mitochondrial uncoupling (respirometry), increased oxidative stress (malondialdehyde measurements), and a heart failure–associated metabolic shift (hyperpolarized magnetic resonance). Mitochondrial membrane potential (5,5´,6,6´‐tetrachloro‐1,1´,3,3´‐tetraethylbenzimidazolocarbocyanine iodide dye assay) and mitochondrial ultrastructure (transmission electron microscopy) were similar between the groups. Proteomics of heart tissue further suggested amplified Src/Ras/Erk1/2 signaling and increased oxidative stress and provided the molecular basis for systolic dysfunction in 8‐month‐old α2+/G301R mice. Conclusions Our findings suggest that ATP1A2 mutation leads to disturbed cardiac metabolism and reduced cardiac function mediated via Na,K‐ATPase–dependent reactive oxygen species signaling through the Src/Ras/Erk1/2 pathway.
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Affiliation(s)
- Christian Staehr
- Department of Biomedicine, Health Aarhus University Aarhus Denmark
| | - Palle Duun Rohde
- Department of Chemistry and Bioscience Aalborg University Aalborg Denmark
| | | | - Steffen Ringgaard
- MR Research Centre Department of Clinical Medicine Aarhus University Aarhus Denmark
| | - Christoffer Laustsen
- MR Research Centre Department of Clinical Medicine Aarhus University Aarhus Denmark
| | - Jacob Johnsen
- Department of Clinical Medicine Aarhus University Aarhus Denmark
| | - Rikke Nielsen
- Department of Biomedicine, Health Aarhus University Aarhus Denmark
| | - Hans Christian Beck
- Department for Clinical Biochemistry and Pharmacology Odense University Hospital Odense Denmark
| | - Jens Preben Morth
- Department of Biotechnology and Biomedicine Technical University of Denmark Kgs. Lyngby Denmark
| | - Karin Lykke-Hartmann
- Department of Biomedicine, Health Aarhus University Aarhus Denmark.,Department of Clinical Medicine Aarhus University Aarhus Denmark.,Department of Clinical Genetics Aarhus University Hospital Aarhus Denmark
| | | | - Denis Abramochkin
- Department of Human and Animal Physiology Biological Faculty Lomonosov Moscow State University Moscow Russia
| | - Mette Nyegaard
- Department of Biomedicine, Health Aarhus University Aarhus Denmark.,Department of Health Science and Technology Aalborg University Aalborg Denmark
| | - Hans Erik Bøtker
- Department of Clinical Medicine Aarhus University Aarhus Denmark
| | - Christian Aalkjaer
- Department of Biomedicine, Health Aarhus University Aarhus Denmark.,Department of Biomedical Sciences Copenhagen University Copenhagen Denmark
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16
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Protective Effect of Trimetazidine on Potassium Ion Homeostasis in Myocardial Tissue in Mice with Heart Failure. BIOMED RESEARCH INTERNATIONAL 2022; 2022:2387860. [PMID: 35097112 PMCID: PMC8791749 DOI: 10.1155/2022/2387860] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 12/20/2022]
Abstract
The occurrence of heart failure (HF) is closely correlated with the disturbance of mitochondrial energy metabolism, and trimetazidine (TMZ) has been regarded as an effective agent in treating HF. Intracellular potassium ion (K+) homeostasis, which is modulated by K+ channels and transporters, is crucial for maintaining normal myocardial function and can be disrupted by HF. This study is aimed at exploring the protective effect of TMZ on K+ homeostasis within myocardial tissue in mice with HF. We observed the pathological changes of myocardial tissue under microscopes and further measured the content of adenosine triphosphate (ATP), the activity of Na+-K+ ATPase, and the expression of ATP1α1 at the mRNA and protein levels. Moreover, we also analyzed the changes in K+ flux across the myocardial tissue in mice. As a result, we found that there was a large amount of myocardial fiber lysis and fracture in HF myocardial tissue. Meanwhile, the potassium flux of mice with HF was reduced, and the expression of ATP1α1, the activity of Na+-K+ ATPase, and the supply and delivery of ATP were also decreased. In contrast, TMZ can effectively treat HF by restoring K+ homeostasis in the local microenvironment of myocardial tissues.
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17
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Blaustein MP, Hamlyn JM, Leenen FHH. Essential contributions of the α2-Na +/K +-ATPase ouabain binding site to cardiac remodeling. Am J Physiol Heart Circ Physiol 2021; 321:H1117-H1118. [PMID: 34842466 DOI: 10.1152/ajpheart.00548.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Frans H H Leenen
- Brain and Heart Research Group, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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18
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Cellini A, Höfler D, Arias-Loza P, Bandleon S, Langsenlehner T, Kohlhaas M, Maack C, Bauer WR, Eder-Negrin P. Reply to Blaustein et al. Am J Physiol Heart Circ Physiol 2021; 321:H119-H1120. [PMID: 34842465 DOI: 10.1152/ajpheart.00596.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Antonella Cellini
- Comprehensive Heart Failure Center, Würzburg, Germany.,Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Dorina Höfler
- Comprehensive Heart Failure Center, Würzburg, Germany.,Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - PaulaA Arias-Loza
- Department of Nuclear Medicine I, University Hospital, Würzburg, Germany
| | - Sandra Bandleon
- Comprehensive Heart Failure Center, Würzburg, Germany.,Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Tanja Langsenlehner
- Department of Therapeutic Radiology and Oncology, Medical University of Graz, Graz, Austria
| | | | | | - Wolfgang R Bauer
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Petra Eder-Negrin
- Comprehensive Heart Failure Center, Würzburg, Germany.,Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
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19
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Cellini A, Höfler D, Arias-Loza PA, Bandleon S, Langsenlehner T, Kohlhaas M, Maack C, Bauer WR, Eder-Negrin P. The α2-isoform of the Na +/K +-ATPase protects against pathological remodeling and β-adrenergic desensitization after myocardial infarction. Am J Physiol Heart Circ Physiol 2021; 321:H650-H662. [PMID: 34448639 DOI: 10.1152/ajpheart.00808.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The role of the Na+/K+-ATPase (NKA) in heart failure associated with myocardial infarction (MI) is poorly understood. The elucidation of its precise function is hampered by the existence of two catalytic NKA isoforms (NKA-α1 and NKA-α2). Our aim was to analyze the effects of an increased NKA-α2 expression on functional deterioration and remodeling during long-term MI treatment in mice and its impact on Ca2+ handling and inotropy of the failing heart. Wild-type (WT) and NKA-α2 transgenic (TG) mice (TG-α2) with a cardiac-specific overexpression of NKA-α2 were subjected to MI injury for 8 wk. As examined by echocardiography, gravimetry, and histology, TG-α2 mice were protected from functional deterioration and adverse cardiac remodeling. Contractility and Ca2+ transients (Fura 2-AM) in cardiomyocytes from MI-treated TG-α2 animals showed reduced Ca2+ amplitudes during pacing or after caffeine application. Ca2+ efflux in cardiomyocytes from TG-α2 mice was accelerated and diastolic Ca2+ levels were decreased. Based on these alterations, sarcomeres exhibited an enhanced sensitization and thus increased contractility. After the acute stimulation with the β-adrenergic agonist isoproterenol (ISO), cardiomyocytes from MI-treated TG-α2 mice responded with increased sarcomere shortenings and Ca2+ peak amplitudes. This positive inotropic response was absent in cardiomyocytes from WT-MI animals. Cardiomyocytes with NKA-α2 as predominant isoform minimize Ca2+ cycling but respond to β-adrenergic stimulation more efficiently during chronic cardiac stress. These mechanisms might improve the β-adrenergic reserve and contribute to functional preservation in heart failure.NEW & NOTEWORTHY Reduced systolic and diastolic calcium levels in cardiomyocytes from NKA-α2 transgenic mice minimize the desensitization of the β-adrenergic signaling system. These effects result in an improved β-adrenergic reserve and prevent functional deterioration and cardiac remodeling.
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Affiliation(s)
- Antonella Cellini
- Comprehensive Heart Failure Center, Würzburg, Germany.,Department of Internal Medicine I, University Hospital, Würzburg, Germany
| | - Dorina Höfler
- Comprehensive Heart Failure Center, Würzburg, Germany.,Department of Internal Medicine I, University Hospital, Würzburg, Germany
| | - Paula A Arias-Loza
- Comprehensive Heart Failure Center, Würzburg, Germany.,Department of Nuclear Medicine I, University Hospital, Würzburg, Germany
| | - Sandra Bandleon
- Comprehensive Heart Failure Center, Würzburg, Germany.,Department of Internal Medicine I, University Hospital, Würzburg, Germany
| | - Tanja Langsenlehner
- Department of Therapeutic Radiology and Oncology, Medical University of Graz, Graz, Austria
| | | | | | - Wolfgang R Bauer
- Department of Internal Medicine I, University Hospital, Würzburg, Germany
| | - Petra Eder-Negrin
- Comprehensive Heart Failure Center, Würzburg, Germany.,Department of Internal Medicine I, University Hospital, Würzburg, Germany
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20
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Grisanti LA. Cardiomyocyte Na +/K +-ATPase-α2 overexpression confers protection in ischemic heart failure. Am J Physiol Heart Circ Physiol 2021; 321:H736-H737. [PMID: 34533399 PMCID: PMC8803311 DOI: 10.1152/ajpheart.00505.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Laurel A Grisanti
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
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21
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Kaplan AD, Joca HC, Boyman L, Greiser M. Calcium Signaling Silencing in Atrial Fibrillation: Implications for Atrial Sodium Homeostasis. Int J Mol Sci 2021; 22:10513. [PMID: 34638854 PMCID: PMC8508839 DOI: 10.3390/ijms221910513] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/14/2021] [Accepted: 09/14/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia, affecting more than 33 million people worldwide. Despite important advances in therapy, AF's incidence remains high, and treatment often results in recurrence of the arrhythmia. A better understanding of the cellular and molecular changes that (1) trigger AF and (2) occur after the onset of AF will help to identify novel therapeutic targets. Over the past 20 years, a large body of research has shown that intracellular Ca2+ handling is dramatically altered in AF. While some of these changes are arrhythmogenic, other changes counteract cellular arrhythmogenic mechanisms (Calcium Signaling Silencing). The intracellular Na+ concentration ([Na+])i is a key regulator of intracellular Ca2+ handling in cardiac myocytes. Despite its importance in the regulation of intracellular Ca2+ handling, little is known about [Na+]i, its regulation, and how it might be changed in AF. Previous work suggests that there might be increases in the late component of the atrial Na+ current (INa,L) in AF, suggesting that [Na+]i levels might be high in AF. Indeed, a pharmacological blockade of INa,L has been suggested as a treatment for AF. Here, we review calcium signaling silencing and changes in intracellular Na+ homeostasis during AF. We summarize the proposed arrhythmogenic mechanisms associated with increases in INa,L during AF and discuss the evidence from clinical trials that have tested the pharmacological INa,L blocker ranolazine in the treatment of AF.
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Affiliation(s)
- Aaron D. Kaplan
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Humberto C. Joca
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
| | - Maura Greiser
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
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22
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Nadar SK, Lip GYH. The heart in hypertension. J Hum Hypertens 2020; 35:383-386. [PMID: 33046827 DOI: 10.1038/s41371-020-00427-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 09/22/2020] [Accepted: 10/01/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Sunil K Nadar
- Department of Medicine, Sultan Qaboos University Hospital, Muscat, Oman.
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK.,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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23
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Leite JA, Isaksen TJ, Heuck A, Scavone C, Lykke-Hartmann K. The α 2 Na +/K +-ATPase isoform mediates LPS-induced neuroinflammation. Sci Rep 2020; 10:14180. [PMID: 32843655 PMCID: PMC7447643 DOI: 10.1038/s41598-020-71027-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/16/2020] [Indexed: 12/12/2022] Open
Abstract
Na+/K+-ATPase is a transmembrane ion pump that is essential for the maintenance of ion gradients and regulation of multiple cellular functions. Na+/K+-ATPase has been associated with nuclear factor kappa B (NFκB) signalling, a signal associated with lipopolysaccharides (LPSs)-induced immune response in connection with activated Toll-like receptor 4 (TLR4) signalling. However, the contribution of Na+/K+-ATPase to regulating inflammatory responses remains elusive. We report that mice haploinsufficient for the astrocyte-enriched α2Na+/K+-ATPase isoform (α2+/G301R mice) have a reduced proinflammatory response to LPS, accompanied by a reduced hypothermic reaction compared to wild type litter mates. Following intraperitoneal injection of LPS, gene expressions of Tnf-α, Il-1β, and Il-6 was reduced in the hypothalamus and hippocampus from α2+/G301R mice compared to α2+/+ littermates. The α2+/G301R mice experienced increased expression of the gene encoding an antioxidant enzyme, NRF2, in hippocampal astrocytes. Our findings indicate that α2Na+/K+-ATPase haploinsufficiency negatively modulates LPS-induced immune responses, highlighting a rational pharmacological target for reducing LPS-induced inflammation.
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Affiliation(s)
- J A Leite
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Department of Pharmacology, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil.,Department of Pharmacology, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - T J Isaksen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - A Heuck
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - C Scavone
- Department of Pharmacology, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - K Lykke-Hartmann
- Department of Biomedicine, Aarhus University, Aarhus, Denmark. .,Department of Clinical Medicine, Aarhus University, 8000, Aarhus C, Denmark. .,Department of Clinical Genetics, Aarhus University Hospital, 8200, Aarhus N, Denmark.
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24
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Obradovic M, Zafirovic S, Soskic S, Stanimirovic J, Trpkovic A, Jevremovic D, Isenovic ER. Effects of IGF-1 on the Cardiovascular System. Curr Pharm Des 2019; 25:3715-3725. [DOI: 10.2174/1381612825666191106091507] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/29/2019] [Indexed: 11/22/2022]
Abstract
:Cardiovascular (CV) diseases are the most common health problems worldwide, with a permanent increase in incidence. Growing evidence underlines that insulin-like growth factor 1 (IGF-1) is a very important hormone responsible for normal CV system physiology. IGF-1 is an anabolic growth hormone, responsible for cell growth, differentiation, proliferation, and survival. Despite systemic effects, IGF-1 exerts a wide array of influences in the CV system affecting metabolic homeostasis, vasorelaxation, cardiac contractility and hypertrophy, autophagy, apoptosis, and antioxidative processes. The vasodilatory effect of IGF-1, is achieved through the regulation of the activity of endothelial nitric oxide synthase (eNOS) and, at least partly, through enhancing inducible NOS (iNOS) activity. Also, IGF-1 stimulates vascular relaxation through regulation of sodium/potassiumadenosine- triphosphatase. Numerous animal studies provided evidence of diverse influences of IGF-1 in the CV system such as vasorelaxation, anti-apoptotic and prosurvival effects. Human studies indicate that low serum levels of free or total IGF-1 contribute to an increased risk of CV and cerebrovascular disease. Large human trials aiming at finding clinical efficacy and outcome of IGF-1-related therapy are of great interest.:We look forward to the development of new IGF 1 therapies with minor side effects. In this review, we discuss the latest literature data regarding the function of IGF-1 in the CV system in the physiological and pathophysiological conditions.
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Affiliation(s)
- Milan Obradovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Sonja Zafirovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Sanja Soskic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Julijana Stanimirovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Andreja Trpkovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Danimir Jevremovic
- Faculty of Stomatology, Pancevo, University Business Academy, 21000 Novi Sad, Serbia
| | - Esma R. Isenovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
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25
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Ding Y, Zhao J, Zhang X, Wang S, Viola KL, Chow FE, Zhang Y, Lippa C, Klein WL, Gong Y. Amyloid Beta Oligomers Target to Extracellular and Intracellular Neuronal Synaptic Proteins in Alzheimer's Disease. Front Neurol 2019; 10:1140. [PMID: 31736856 PMCID: PMC6838211 DOI: 10.3389/fneur.2019.01140] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/11/2019] [Indexed: 12/19/2022] Open
Abstract
Introduction: β-Amyloid protein (Aβ) putatively plays a seminal role in synaptic loss in Alzheimer's disease (AD). While there is no consensus regarding the synaptic-relevant species of Aβ, it is known that Aβ oligomers (AβOs) are noticeably increased in the early stages of AD, localizing at or within the synapse. In cell and animal models, AβOs have been shown to attach to synapses and instigate synapse dysfunction and deterioration. To establish the pathological mechanism of synaptic loss in AD, it will be important to identify the synaptic targets to which AβOs attach. Methods: An unbiased approach using far western ligand blots has identified three synaptic proteins to which AβOs specifically attach. These proteins (p100, p140, and p260) were subsequently enriched by detergent extraction, ultracentrifugation, and CHT-HPLC column separation, and sequenced by LC-MS/MS. P100, p140, and p260 were identified. These levels of AβOs targets in human AD and aging frontal cortexes were analyzed by quantitative proteomics and western-blot. The polyclonal antibody to AβOs was developed and used to block the toxicity of AβOs. The data were analyzed with one-way analysis of variance. Results: AβOs binding proteins p100, p140, and p260 were identified as Na/K-ATPase, synGap, and Shank3, respectively. α3-Na/K-ATPase, synGap, and Shank3 proteins showed loss in the postsynaptic density (PSD) of human AD frontal cortex. In short term experiments, oligomers of Aβ inhibited Na/K-ATPase at the synapse. Na/K-ATPase activity was restored by an antibody specific for soluble forms of Aβ. α3-Na/K-ATPase protein and synaptic β-amyloid peptides were pulled down from human AD synapses by co-immunoprecipitation. Results suggest synaptic dysfunction in early stages of AD may stem from inhibition of Na/K-ATPase activity by Aβ oligomers, while later stages could hypothetically result from disrupted synapse structure involving the PSD proteins synGap and Shank3. Conclusion: We identified three AβO binding proteins as α3-Na/K-ATPase, synGap, and Shank3. Soluble Aβ oligomers appear capable of attacking neurons via specific extracellular as well as intracellular synaptic proteins. Impact on these proteins hypothetically could lead to synaptic dysfunction and loss, and could serve as novel therapeutic targets for AD treatment by antibodies or other agents.
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Affiliation(s)
- Yu Ding
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Jiahui Zhao
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xunle Zhang
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Shanshan Wang
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Kirsten L. Viola
- Department of Neurobiology and Neurology, Northwestern University, Evanston, IL, United States
| | - Frances E. Chow
- Department of Neurology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Yang Zhang
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Carol Lippa
- Department of Neurology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - William L. Klein
- Department of Neurobiology and Neurology, Northwestern University, Evanston, IL, United States
| | - Yuesong Gong
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
- Department of Neurology, Drexel University College of Medicine, Philadelphia, PA, United States
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26
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Stimulation of Na +/K +-ATPase with an Antibody against Its 4 th Extracellular Region Attenuates Angiotensin II-Induced H9c2 Cardiomyocyte Hypertrophy via an AMPK/SIRT3/PPAR γ Signaling Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:4616034. [PMID: 31636805 PMCID: PMC6766118 DOI: 10.1155/2019/4616034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 07/09/2019] [Accepted: 08/02/2019] [Indexed: 02/06/2023]
Abstract
Activation of the renin-angiotensin system (RAS) contributes to the pathogenesis of cardiovascular diseases. Sodium potassium ATPase (NKA) expression and activity are often regulated by angiotensin II (Ang II). This study is aimed at investigating whether DR-Ab, an antibody against 4th extracellular region of NKA, can protect Ang II-induced cardiomyocyte hypertrophy. Our results showed that Ang II treatment significantly reduced NKA activity and membrane expression. Pretreatment with DR-Ab preserved cell size in Ang II-induced cardiomyopathy by stabilizing the plasma membrane expression of NKA and restoring its activity. DR-Ab reduced intracellular ROS generation through inhibition of NADPH oxidase activity and protection of mitochondrial functions in Ang II-treated H9c2 cardiomyocytes. Pharmacological manipulation and Western blotting analysis demonstrated the cardioprotective effects were mediated by the activation of the AMPK/Sirt-3/PPARγ signaling pathway. Taken together, our results suggest that dysfunction of NKA is an important mechanism for Ang II-induced cardiomyopathy and DR-Ab may be a novel and promising therapeutic approach to treat cardiomyocyte hypertrophy.
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Correll RN, Makarewich CA, Zhang H, Zhang C, Sargent MA, York AJ, Berretta RM, Chen X, Houser SR, Molkentin JD. Caveolae-localized L-type Ca2+ channels do not contribute to function or hypertrophic signalling in the mouse heart. Cardiovasc Res 2018; 113:749-759. [PMID: 28402392 DOI: 10.1093/cvr/cvx046] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 03/07/2017] [Indexed: 12/17/2022] Open
Abstract
Aims L-type Ca2+ channels (LTCCs) in adult cardiomyocytes are localized to t-tubules where they initiate excitation-contraction coupling. Our recent work has shown that a subpopulation of LTCCs found at the surface sarcolemma in caveolae of adult feline cardiomyocytes can also generate a Ca2+ microdomain that activates nuclear factor of activated T-cells signaling and cardiac hypertrophy, although the relevance of this paradigm to hypertrophy regulation in vivo has not been examined. Methods and results Here we generated heart-specific transgenic mice with a putative caveolae-targeted LTCC activator protein that was ineffective in initiating or enhancing cardiac hypertrophy in vivo. We also generated transgenic mice with cardiac-specific overexpression of a putative caveolae-targeted inhibitor of LTCCs, and while this protein inhibited caveolae-localized LTCCs without effects on global Ca2+ handling, it similarly had no effect on cardiac hypertrophy in vivo. Cardiac hypertrophy was elicited by pressure overload for 2 or 12 weeks or with neurohumoral agonist infusion. Caveolae-specific LTCC activator or inhibitor transgenic mice showed no greater change in nuclear factor of activated T-cells activity after 2 weeks of pressure overload stimulation compared with control mice. Conclusion Our results indicate that LTCCs in the caveolae microdomain do not affect cardiac function and are not necessary for the regulation of hypertrophic signaling in the adult mouse heart.
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Affiliation(s)
- Robert N Correll
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, Cincinnati, OH 45229, USA
| | - Catherine A Makarewich
- Department of Physiology, Cardiovascular Research Center, Temple University School of Medicine, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Hongyu Zhang
- Department of Physiology, Cardiovascular Research Center, Temple University School of Medicine, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Chen Zhang
- Department of Physiology, Cardiovascular Research Center, Temple University School of Medicine, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Michelle A Sargent
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, Cincinnati, OH 45229, USA
| | - Allen J York
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, Cincinnati, OH 45229, USA
| | - Remus M Berretta
- Department of Physiology, Cardiovascular Research Center, Temple University School of Medicine, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Xiongwen Chen
- Department of Physiology, Cardiovascular Research Center, Temple University School of Medicine, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Steven R Houser
- Department of Physiology, Cardiovascular Research Center, Temple University School of Medicine, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, Cincinnati, OH 45229, USA.,Department of Pediatrics, Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, 240 Albert Sabin Way, Cincinnati, OH 45229-3039, USA
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28
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Howie J, Wypijewski KJ, Plain F, Tulloch LB, Fraser NJ, Fuller W. Greasing the wheels or a spanner in the works? Regulation of the cardiac sodium pump by palmitoylation. Crit Rev Biochem Mol Biol 2018; 53:175-191. [PMID: 29424237 DOI: 10.1080/10409238.2018.1432560] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The ubiquitous sodium/potassium ATPase (Na pump) is the most abundant primary active transporter at the cell surface of multiple cell types, including ventricular myocytes in the heart. The activity of the Na pump establishes transmembrane ion gradients that control numerous events at the cell surface, positioning it as a key regulator of the contractile and metabolic state of the myocardium. Defects in Na pump activity and regulation elevate intracellular Na in cardiac muscle, playing a causal role in the development of cardiac hypertrophy, diastolic dysfunction, arrhythmias and heart failure. Palmitoylation is the reversible conjugation of the fatty acid palmitate to specific protein cysteine residues; all subunits of the cardiac Na pump are palmitoylated. Palmitoylation of the pump's accessory subunit phospholemman (PLM) by the cell surface palmitoyl acyl transferase DHHC5 leads to pump inhibition, possibly by altering the relationship between the pump catalytic α subunit and specifically bound membrane lipids. In this review, we discuss the functional impact of PLM palmitoylation on the cardiac Na pump and the molecular basis of recognition of PLM by its palmitoylating enzyme DHHC5, as well as effects of palmitoylation on Na pump cell surface abundance in the cardiac muscle. We also highlight the numerous unanswered questions regarding the cellular control of this fundamentally important regulatory process.
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Affiliation(s)
- Jacqueline Howie
- a Institute of Cardiovascular and Medical Sciences , University of Glasgow , Glasgow , UK
| | | | - Fiona Plain
- b Molecular and Clinical Medicine , University of Dundee , Dundee , UK
| | - Lindsay B Tulloch
- b Molecular and Clinical Medicine , University of Dundee , Dundee , UK
| | - Niall J Fraser
- b Molecular and Clinical Medicine , University of Dundee , Dundee , UK
| | - William Fuller
- a Institute of Cardiovascular and Medical Sciences , University of Glasgow , Glasgow , UK
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29
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Hu Y, Wang Z, Ge N, Huang T, Zhang M, Wang H. Sodium pump alpha-2 subunit (ATP1A2) alleviates cardiomyocyte anoxia-reoxygenation injury via inhibition of endoplasmic reticulum stress-related apoptosis. Can J Physiol Pharmacol 2018; 96:515-520. [PMID: 29394489 DOI: 10.1139/cjpp-2017-0349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have found decreased functional capacity of the sodium pump (Na+-K+-ATPase) alpha and beta subunits and recovery of Na+-K+-ATPase activity significantly decreased myocyte apoptosis in myocardial ischemia-reperfusion (I/R) injury. However, the potential role of the Na+-K+-ATPase α-2 subunit (ATP1A2) in cardiomyocyte anoxia-reoxygenation (A/R) injury has not been elucidated. Rat myocardial cells were subjected to siRNA transfection followed by A/R injury. Apoptosis and expression of endoplasmic reticulum (ER) stress proteins CHOP, GRP78, and caspase-12 were detected in 4 groups of cells: ATP1A2 siRNA + A/R, control siRNA + A/R, control, and A/R injury model. We found that apoptosis was significantly elevated in the ATP1A2 siRNA + A/R group as compared with control siRNA + A/R, control, and A/R injury model groups (p < 0.05, p < 0.01, and p < 0.05). Furthermore, expression of CHOP, GRP78, and caspase-12 were significantly elevated in the ATP1A2 siRNA + A/R group as compared with control siRNA + A/R, control, and A/R injury model groups (p < 0.05, p < 0.01, and p < 0.05). Our findings suggest that cardiomyocyte ATP1A2 is a target of A/R injury, and its cardioprotective function may be mediated via inhibiting the ER-stress-related apoptosis.
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Affiliation(s)
- Yulong Hu
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China.,Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Zheng Wang
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China.,Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Nannan Ge
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China.,Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Ting Huang
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China.,Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Mingchao Zhang
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China.,Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Hegui Wang
- Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China.,Department of Cardiology, Yijishan Hospital of Wannan Medical College, Wuhu, China
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30
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Yu H, Cui X, Zhang J, Xie JX, Banerjee M, Pierre SV, Xie Z. Heterogeneity of signal transduction by Na-K-ATPase α-isoforms: role of Src interaction. Am J Physiol Cell Physiol 2018; 314:C202-C210. [PMID: 29118027 PMCID: PMC5866435 DOI: 10.1152/ajpcell.00124.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 11/22/2022]
Abstract
Of the four Na-K-ATPase α-isoforms, the ubiquitous α1 Na-K-ATPase possesses both ion transport and Src-dependent signaling functions. Mechanistically, we have identified two putative pairs of domain interactions between α1 Na-K-ATPase and Src that are critical for α1 signaling function. Our subsequent report that α2 Na-K-ATPase lacks these putative Src-binding sites and fails to carry on Src-dependent signaling further supported our proposed model of direct interaction between α1 Na-K-ATPase and Src but fell short of providing evidence for a causative role. This hypothesis was specifically tested here by introducing key residues of the two putative Src-interacting domains present on α1 but not α2 sequence into the α2 polypeptide, generating stable cell lines expressing this mutant, and comparing its signaling properties to those of α2-expressing cells. The mutant α2 was fully functional as a Na-K-ATPase. In contrast to wild-type α2, the mutant gained α1-like signaling function, capable of Src interaction and regulation. Consistently, the expression of mutant α2 redistributed Src into caveolin-1-enriched fractions and allowed ouabain to activate Src-mediated signaling cascades, unlike wild-type α2 cells. Finally, mutant α2 cells exhibited a growth phenotype similar to that of the α1 cells and proliferated much faster than wild-type α2 cells. These findings reveal the structural requirements for the Na-K-ATPase to function as a Src-dependent receptor and provide strong evidence of isoform-specific Src interaction involving the identified key amino acids. The sequences surrounding the putative Src-binding sites in α2 are highly conserved across species, suggesting that the lack of Src binding may play a physiologically important and isoform-specific role.
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Affiliation(s)
- Hui Yu
- Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyu Cui
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
| | - Jue Zhang
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
| | - Joe X Xie
- Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia
| | - Moumita Banerjee
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
| | - Sandrine V Pierre
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
| | - Zijian Xie
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
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31
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Role of the β 3-adrenergic receptor subtype in catecholamine-induced myocardial remodeling. Mol Cell Biochem 2018; 446:149-160. [PMID: 29363058 DOI: 10.1007/s11010-018-3282-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/16/2018] [Indexed: 10/18/2022]
Abstract
β3-Adrenoceptors (AR) stimulate cardiac Na+/K+ pump in healthy hearts. β3-ARs are upregulated by persistent sympathetic hyperactivity; however, their effect on Na+/K+ ATPase activity and ventricular function in this condition is still unknown. Here, we investigate preventive effects of additional β3-AR activation (BRL) on Na+/K+ ATPase activity and in vivo hemodynamics in a model of noradrenaline-induced hypertrophy. Rats received NA or NA plus simultaneously administered BRL in vivo infusion for 14 days; their cardiac function was investigated by left ventricular pressure-volume analysis. Moreover, fibrosis and apoptosis were also assessed histologically. NA induced an hypertrophic pattern, as detected by morphological, histological, and biochemical markers. Additional BRL exposure reversed the hypertrophic pattern and restored Na+/K+ ATPase activity. NA treatment increased systolic function and depressed diastolic function (slowed relaxation). Additional BRL treatment reversed most NA-induced hemodynamic changes. NA decreased Na+/K+ pump α2 subunit expression selectively, a change also reversed by additional BRL treatment. Increasing β3-AR stimulation may prevent the consequences of chronic NA exposure on Na+/K+ pump and in vivo hemodynamics. β3-AR agonism may thus represent a new therapeutic strategy for pharmacological modulation of hypertrophy under conditions of chronically enhanced sympathetic activity.
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32
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Tang G, Shen Y, Gao P, Song SS, Si LY. Klotho attenuates isoproterenol-induced hypertrophic response in H9C2 cells by activating Na+/K+-ATPase and inhibiting the reverse mode of Na+/Ca2+-exchanger. In Vitro Cell Dev Biol Anim 2018; 54:250-256. [DOI: 10.1007/s11626-017-0215-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 11/09/2017] [Indexed: 12/20/2022]
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33
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Puerarin Suppresses Na+-K+-ATPase-Mediated Systemic Inflammation and CD36 Expression, and Alleviates Cardiac Lipotoxicity In Vitro and In Vivo. J Cardiovasc Pharmacol 2017; 68:465-472. [PMID: 27606935 DOI: 10.1097/fjc.0000000000000431] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Puerarin, a type of isoflavone, was shown to have multiple protective effects on myocardial injury. The objective of this study was to investigate the role of puerarin in the progression of lipotoxic cardiomyopathy. Primary cardiomyocytes were isolated from FATP1 transgenic (Tg) mice with lipotoxic cardiomyopathy, and various concentrations of puerarin were used to incubate with the cardiomyocytes. Our results showed low-dose puerarin (≤20 μM) treatment increased the cell viability and decreased the accumulation of free fatty acid (FFA). The data on enzyme-linked immunosorbent assay indicated that 15 μM puerarin treatment greatly increased Na-K-ATPase activity and decreased C-reactive protein secretion, thus suppressing the expression of CD36, a key contributor to the FFA accumulation. Additionally, low-dose puerarin (≤100 mg/kg body weight) administration improved Na-K-ATPase activity. Our data on serum analysis and histological detection in vivo indicated that systemic inflammation, CD36-induced lipid infiltration, and cardiomyocyte apoptosis were markedly alleviated in Tg mice injected with 90 mg/kg dose of puerarin. Finally, the uptake rates of H-palmitate and C-glucose were monitored on ex vivo working hearts that were obtained from wild-type (WT), Tg-control, and Tg-puerarin mice. Compared with WT hearts, Tg hearts displayed a significant decrease in Na/K-ATPase activity and glucose consumption rate and an increase in palmitate uptake rate and FFA accumulation. In Tg-puerarin hearts, Na/K-ATPase activity and glucose consumption rate were significantly rescued, and palmitate uptake and FFA accumulation were sharply suppressed. In conclusion, low-dose puerarin suppressed Na-K-ATPase-mediated CD36 expression and systemic inflammation and alleviated cardiac lipotoxicity in vitro and in vivo.
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34
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Blaustein MP. How does pressure overload cause cardiac hypertrophy and dysfunction? High-ouabain affinity cardiac Na + pumps are crucial. Am J Physiol Heart Circ Physiol 2017; 313:H919-H930. [PMID: 28733446 PMCID: PMC5792198 DOI: 10.1152/ajpheart.00131.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 07/18/2017] [Accepted: 07/18/2017] [Indexed: 12/17/2022]
Abstract
Left ventricular hypertrophy is frequently observed in hypertensive patients and is believed to be due to the pressure overload and cardiomyocyte stretch. Three recent reports on mice with genetically engineered Na+ pumps, however, have demonstrated that cardiac ouabain-sensitive α2-Na+ pumps play a key role in the pathogenesis of transaortic constriction-induced hypertrophy. Hypertrophy was delayed/attenuated in mice with mutant, ouabain-resistant α2-Na+ pumps and in mice with cardiac-selective knockout or transgenic overexpression of α2-Na+ pumps. The latter, seemingly paradoxical, findings can be explained by comparing the numbers of available (ouabain-free) high-affinity (α2) ouabain-binding sites in wild-type, knockout, and transgenic hearts. Conversely, hypertrophy was accelerated in α2-ouabain-resistant (R) mice in which the normally ouabain-resistant α1-Na+ pumps were mutated to an ouabain-sensitive (S) form (α1S/Sα2R/R or "SWAP" vs. wild-type or α1R/R α2S/S mice). Furthermore, transaortic constriction-induced hypertrophy in SWAP mice was prevented/reversed by immunoneutralizing circulating endogenous ouabain (EO). These findings show that EO and its receptor, ouabain-sensitive α2, are critical factors in pressure overload-induced cardiac hypertrophy. This complements reports linking elevated plasma EO to hypertension, cardiac hypertrophy, and failure in humans and elucidates the underappreciated role of the EO-Na+ pump pathway in cardiovascular disease.
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Affiliation(s)
- Mordecai P. Blaustein
- Departments of Physiology and Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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35
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Olgar Y, Celen MC, Yamasan BE, Ozturk N, Turan B, Ozdemir S. Rho-kinase inhibition reverses impaired Ca 2+ handling and associated left ventricular dysfunction in pressure overload-induced cardiac hypertrophy. Cell Calcium 2017; 67:81-90. [DOI: 10.1016/j.ceca.2017.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 08/24/2017] [Accepted: 09/09/2017] [Indexed: 10/18/2022]
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36
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Leenen FHH, Blaustein MP, Hamlyn JM. Update on angiotensin II: new endocrine connections between the brain, adrenal glands and the cardiovascular system. Endocr Connect 2017; 6:R131-R145. [PMID: 28855243 PMCID: PMC5613704 DOI: 10.1530/ec-17-0161] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/30/2017] [Indexed: 12/11/2022]
Abstract
In the brain, angiotensinergic pathways play a major role in chronic regulation of cardiovascular and electrolyte homeostasis. Increases in plasma angiotensin II (Ang II), aldosterone, [Na+] and cytokines can directly activate these pathways. Chronically, these stimuli also activate a slow neuromodulatory pathway involving local aldosterone, mineralocorticoid receptors (MRs), epithelial sodium channels and endogenous ouabain (EO). This pathway increases AT1R and NADPH oxidase subunits and maintains/further increases the activity of angiotensinergic pathways. These brain pathways not only increase the setpoint of sympathetic activity per se, but also enhance its effectiveness by increasing plasma EO and EO-dependent reprogramming of arterial and cardiac function. Blockade of any step in this slow pathway or of AT1R prevents Ang II-, aldosterone- or salt and renal injury-induced forms of hypertension. MR/AT1R activation in the CNS also contributes to the activation of sympathetic activity, the circulatory and cardiac RAAS and increase in circulating cytokines in HF post MI. Chronic central infusion of an aldosterone synthase inhibitor, MR blocker or AT1R blocker prevents a major part of the structural remodeling of the heart and the decrease in LV function post MI, indicating that MR activation in the CNS post MI depends on aldosterone, locally produced in the CNS. Thus, Ang II, aldosterone and EO are not simply circulating hormones that act on the CNS but rather they are also paracrine neurohormones, locally produced in the CNS, that exert powerful effects in key CNS pathways involved in the long-term control of sympathetic and neuro-endocrine function and cardiovascular homeostasis.
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Affiliation(s)
- Frans H H Leenen
- Brain and Heart Research GroupUniversity of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Mordecai P Blaustein
- Department of PhysiologyUniversity of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of MedicineUniversity of Maryland School of Medicine, Baltimore, Maryland, USA
| | - John M Hamlyn
- Department of PhysiologyUniversity of Maryland School of Medicine, Baltimore, Maryland, USA
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37
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Changes in cardiac Na +/K +-ATPase expression and activity in female rats fed a high-fat diet. Mol Cell Biochem 2017; 436:49-58. [PMID: 28567564 DOI: 10.1007/s11010-017-3077-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 05/25/2017] [Indexed: 12/27/2022]
Abstract
The aim of this study was to investigate whether the presence of endogenous estradiol alters the effects of a high-fat (HF) diet on activity/expression of the cardiac Na+/K+-ATPase, via PI3K/IRS and RhoA/ROCK signalling cascades in female rats. For this study, female Wistar rats (8 weeks old, 150-200 g) were fed a standard diet or a HF diet (balanced diet for laboratory rats enriched with 42% fat) for 10 weeks. The results show that rats fed a HF diet exhibited a decrease in phosphorylation of the α1 subunit of Na+/K+-ATPase by 30% (p < 0.05), expression of total α1 subunit of Na+/K+-ATPase by 31% (p < 0.05), and association of IRS1 with p85 subunit of PI3K by 42% (p < 0.05), while the levels of cardiac RhoA and ROCK2 were significantly increased by 84% (p < 0.01) and 62% (p < 0.05), respectively. Our results suggest that a HF diet alters cardiac Na+/K+-ATPase expression via molecular mechanisms involving RhoA/ROCK and IRS-1/PI3K signalling in female rats.
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Kirschmer N, Bandleon S, von Ehrlich-Treuenstätt V, Hartmann S, Schaaf A, Lamprecht AK, Miranda-Laferte E, Langsenlehner T, Ritter O, Eder P. TRPC4α and TRPC4β Similarly Affect Neonatal Cardiomyocyte Survival during Chronic GPCR Stimulation. PLoS One 2016; 11:e0168446. [PMID: 27992507 PMCID: PMC5167390 DOI: 10.1371/journal.pone.0168446] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 12/01/2016] [Indexed: 11/19/2022] Open
Abstract
The Transient Receptor Potential Channel Subunit 4 (TRPC4) has been considered as a crucial Ca2+ component in cardiomyocytes promoting structural and functional remodeling in the course of pathological cardiac hypertrophy. TRPC4 assembles as homo or hetero-tetramer in the plasma membrane, allowing a non-selective Na+ and Ca2+ influx. Gαq protein-coupled receptor (GPCR) stimulation is known to increase TRPC4 channel activity and a TRPC4-mediated Ca2+ influx which has been regarded as ideal Ca2+ source for calcineurin and subsequent nuclear factor of activated T-cells (NFAT) activation. Functional properties of TRPC4 are also based on the expression of the TRPC4 splice variants TRPC4α and TRPC4β. Aim of the present study was to analyze cytosolic Ca2+ signals, signaling, hypertrophy and vitality of cardiomyocytes in dependence on the expression level of either TRPC4α or TRPC4β. The analysis of Ca2+ transients in neonatal rat cardiomyocytes (NRCs) showed that TRPC4α and TRPC4β affected Ca2+ cycling in beating cardiomyocytes with both splice variants inducing an elevation of the Ca2+ transient amplitude at baseline and TRPC4β increasing the Ca2+ peak during angiotensin II (Ang II) stimulation. NRCs infected with TRPC4β (Ad-C4β) also responded with a sustained Ca2+ influx when treated with Ang II under non-pacing conditions. Consistent with the Ca2+ data, NRCs infected with TRPC4α (Ad-C4α) showed an elevated calcineurin/NFAT activity and a baseline hypertrophic phenotype but did not further develop hypertrophy during chronic Ang II/phenylephrine stimulation. Down-regulation of endogenous TRPC4α reversed these effects, resulting in less hypertrophy of NRCs at baseline but a markedly increased hypertrophic enlargement after chronic agonist stimulation. Ad-C4β NRCs did not exhibit baseline calcineurin/NFAT activity or hypertrophy but responded with an increased calcineurin/NFAT activity after GPCR stimulation. However, this effect was not translated into an increased propensity towards hypertrophy but rather less hypertrophy during GPCR stimulation. Further analyses revealed that, although hypertrophy was preserved in Ad-C4α NRCs and even attenuated in Ad-C4β NRCs, cardiomyocytes had an increased apoptosis rate and thus were less viable after chronic GPCR stimulation. These findings suggest that TRPC4α and TRPC4β differentially affect Ca2+ signals, calcineurin/NFAT signaling and hypertrophy but similarly impair cardiomyocyte viability during GPCR stimulation.
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Affiliation(s)
- Nadine Kirschmer
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Comprehensive Heart Failure Center Würzburg, University Hospital Würzburg, Würzburg, Germany
| | - Sandra Bandleon
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Comprehensive Heart Failure Center Würzburg, University Hospital Würzburg, Würzburg, Germany
| | - Viktor von Ehrlich-Treuenstätt
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Comprehensive Heart Failure Center Würzburg, University Hospital Würzburg, Würzburg, Germany
| | - Sonja Hartmann
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, United States of America
| | - Alice Schaaf
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Comprehensive Heart Failure Center Würzburg, University Hospital Würzburg, Würzburg, Germany
| | - Anna-Karina Lamprecht
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Comprehensive Heart Failure Center Würzburg, University Hospital Würzburg, Würzburg, Germany
| | | | - Tanja Langsenlehner
- Department of Therapeutic Radiology and Oncology, Medical University of Graz, Graz, Austria
| | - Oliver Ritter
- Department of Cardiology and Pulmology, Brandenburg Medical School, University Hospital Brandenburg, Brandenburg, Germany
| | - Petra Eder
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Comprehensive Heart Failure Center Würzburg, University Hospital Würzburg, Würzburg, Germany
- * E-mail:
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Bai Y, Wu J, Li D, Morgan EE, Liu J, Zhao X, Walsh A, Saikumar J, Tinkel J, Joe B, Gupta R, Liu L. Differential roles of caveolin-1 in ouabain-induced Na+/K+-ATPase cardiac signaling and contractility. Physiol Genomics 2016; 48:739-748. [PMID: 27519543 PMCID: PMC5243228 DOI: 10.1152/physiolgenomics.00042.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/03/2016] [Indexed: 11/22/2022] Open
Abstract
Binding of ouabain to cardiac Na+/K+-ATPase initiates cell signaling and causes contractility in cardiomyocytes. It is widely accepted that caveolins, structural proteins of caveolae, have been implicated in signal transduction. It is known that caveolae play a role in Na+/K+-ATPase functions. Regulation of caveolin-1 in ouabain-mediated cardiac signaling and contractility has never been reported. The aim of this study is to compare ouabain-induced cardiac signaling and contractility in wild-type (WT) and caveolin-1 knockout (cav-1 KO) mice. In contrast with WT cardiomyocytes, ouabain-induced signaling e.g., activation of phosphoinositide 3-kinase-α/Akt and extracellular signal-regulated kinases (ERK)1/2, and hypertrophic growth were significantly reduced in cav-1 KO cardiomyocytes. Interactions of the Na+/K+-ATPase α1-subunit with caveolin-3 and the Na+/K+-ATPase α1-subunit with PI3K-α were also decreased in cav-1 KO cardiomyocytes. The results from cav-1 KO mouse embryonic fibroblasts also proved that cav-1 significantly attenuated ouabain-induced ERK1/2 activation without alteration in protein and cholesterol distribution in caveolae/lipid rafts. Intriguingly, the effect of ouabain induced positive inotropy in vivo (via transient infusion of ouabain, 0.48 nmol/g body wt) was not attenuated in cav-1 KO mice. Furthermore, ouabain (1-100 μM) induced dose-dependent contractility in isolated working hearts from WT and cav-1 KO mice. The effects of ouabain on contractility between WT and cav-1 KO mice were not significantly different. These results demonstrated differential roles of cav-1 in the regulation of ouabain signaling and contractility. Signaling by ouabain, in contrast to contractility, may be a redundant property of Na+/K+-ATPase.
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Affiliation(s)
- Yan Bai
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio; Pediatrics Department of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China
| | - Jian Wu
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Daxiang Li
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio; State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui, China; and
| | - Eric E Morgan
- Center for Hypertension and Personalized Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Jiang Liu
- Department of Pharmacology, Physiology and Toxicology, JCE School of Medicine, Marshall University, Huntington, West Virginia
| | - Xiaochen Zhao
- Department of Physiology and Pharmacology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Aaron Walsh
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Jagannath Saikumar
- Department of Physiology and Pharmacology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Jodi Tinkel
- Department of Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Bina Joe
- Department of Physiology and Pharmacology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio; Center for Hypertension and Personalized Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Rajesh Gupta
- Department of Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Lijun Liu
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio; Department of Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio; Center for Hypertension and Personalized Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio;
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Habeck M, Tokhtaeva E, Nadav Y, Ben Zeev E, Ferris SP, Kaufman RJ, Bab-Dinitz E, Kaplan JH, Dada LA, Farfel Z, Tal DM, Katz A, Sachs G, Vagin O, Karlish SJD. Selective Assembly of Na,K-ATPase α2β2 Heterodimers in the Heart: DISTINCT FUNCTIONAL PROPERTIES AND ISOFORM-SELECTIVE INHIBITORS. J Biol Chem 2016; 291:23159-23174. [PMID: 27624940 DOI: 10.1074/jbc.m116.751735] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Indexed: 12/31/2022] Open
Abstract
The Na,K-ATPase α2 subunit plays a key role in cardiac muscle contraction by regulating intracellular Ca2+, whereas α1 has a more conventional role of maintaining ion homeostasis. The β subunit differentially regulates maturation, trafficking, and activity of α-β heterodimers. It is not known whether the distinct role of α2 in the heart is related to selective assembly with a particular one of the three β isoforms. We show here by immunofluorescence and co-immunoprecipitation that α2 is preferentially expressed with β2 in T-tubules of cardiac myocytes, forming α2β2 heterodimers. We have expressed human α1β1, α2β1, α2β2, and α2β3 in Pichia pastoris, purified the complexes, and compared their functional properties. α2β2 and α2β3 differ significantly from both α2β1 and α1β1 in having a higher K0.5K+ and lower K0.5Na+ for activating Na,K-ATPase. These features are the result of a large reduction in binding affinity for extracellular K+ and shift of the E1P-E2P conformational equilibrium toward E1P. A screen of perhydro-1,4-oxazepine derivatives of digoxin identified several derivatives (e.g. cyclobutyl) with strongly increased selectivity for inhibition of α2β2 and α2β3 over α1β1 (range 22-33-fold). Molecular modeling suggests a possible basis for isoform selectivity. The preferential assembly, specific T-tubular localization, and low K+ affinity of α2β2 could allow an acute response to raised ambient K+ concentrations in physiological conditions and explain the importance of α2β2 for cardiac muscle contractility. The high sensitivity of α2β2 to digoxin derivatives explains beneficial effects of cardiac glycosides for treatment of heart failure and potential of α2β2-selective digoxin derivatives for reducing cardiotoxicity.
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Affiliation(s)
| | - Elmira Tokhtaeva
- the Department of Physiology, School of Medicine, UCLA and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073
| | - Yotam Nadav
- From the Department of Biomolecular Sciences and
| | - Efrat Ben Zeev
- Israel National Centre for Personalized Medicine, Weizmann Institute of Science, Rehovoth 7610001, Israel
| | - Sean P Ferris
- the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109
| | - Randal J Kaufman
- the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109
| | | | - Jack H Kaplan
- the Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago, Illinois 60607, and
| | - Laura A Dada
- the Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Zvi Farfel
- From the Department of Biomolecular Sciences and.,the School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Daniel M Tal
- From the Department of Biomolecular Sciences and
| | - Adriana Katz
- From the Department of Biomolecular Sciences and
| | - George Sachs
- the Department of Physiology, School of Medicine, UCLA and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073
| | - Olga Vagin
- the Department of Physiology, School of Medicine, UCLA and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073,
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Liu L, Wu J, Kennedy DJ. Regulation of Cardiac Remodeling by Cardiac Na(+)/K(+)-ATPase Isoforms. Front Physiol 2016; 7:382. [PMID: 27667975 PMCID: PMC5016610 DOI: 10.3389/fphys.2016.00382] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/22/2016] [Indexed: 12/20/2022] Open
Abstract
Cardiac remodeling occurs after cardiac pressure/volume overload or myocardial injury during the development of heart failure and is a determinant of heart failure. Preventing or reversing remodeling is a goal of heart failure therapy. Human cardiomyocyte Na+/K+-ATPase has multiple α isoforms (1–3). The expression of the α subunit of the Na+/K+-ATPase is often altered in hypertrophic and failing hearts. The mechanisms are unclear. There are limited data from human cardiomyocytes. Abundant evidences from rodents show that Na+/K+-ATPase regulates cardiac contractility, cell signaling, hypertrophy and fibrosis. The α1 isoform of the Na+/K+-ATPase is the ubiquitous isoform and possesses both pumping and signaling functions. The α2 isoform of the Na+/K+-ATPase regulates intracellular Ca2+ signaling, contractility and pathological hypertrophy. The α3 isoform of the Na+/K+-ATPase may also be a target for cardiac hypertrophy. Restoration of cardiac Na+/K+-ATPase expression may be an effective approach for prevention of cardiac remodeling. In this article, we will overview: (1) the distribution and function of isoform specific Na+/K+-ATPase in the cardiomyocytes. (2) the role of cardiac Na+/K+-ATPase in the regulation of cell signaling, contractility, cardiac hypertrophy and fibrosis in vitro and in vivo. Selective targeting of cardiac Na+/K+-ATPase isoform may offer a new target for the prevention of cardiac remodeling.
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Affiliation(s)
- Lijun Liu
- Department of Medicine, College of Medicine and Life Sciences, University of Toledo Toledo, OH, USA
| | - Jian Wu
- Center for Craniofacial Molecular Biology, University of Southern California Los Angeles, CA, USA
| | - David J Kennedy
- Department of Medicine, College of Medicine and Life Sciences, University of Toledo Toledo, OH, USA
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Blaustein MP, Chen L, Hamlyn JM, Leenen FHH, Lingrel JB, Wier WG, Zhang J. Pivotal role of α2 Na + pumps and their high affinity ouabain binding site in cardiovascular health and disease. J Physiol 2016; 594:6079-6103. [PMID: 27350568 DOI: 10.1113/jp272419] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/18/2016] [Indexed: 12/13/2022] Open
Abstract
Reduced smooth muscle (SM)-specific α2 Na+ pump expression elevates basal blood pressure (BP) and increases BP sensitivity to angiotensin II (Ang II) and dietary NaCl, whilst SM-α2 overexpression lowers basal BP and decreases Ang II/salt sensitivity. Prolonged ouabain infusion induces hypertension in rodents, and ouabain-resistant mutation of the α2 ouabain binding site (α2R/R mice) confers resistance to several forms of hypertension. Pressure overload-induced heart hypertrophy and failure are attenuated in cardio-specific α2 knockout, cardio-specific α2 overexpression and α2R/R mice. We propose a unifying hypothesis that reconciles these apparently disparate findings: brain mechanisms, activated by Ang II and high NaCl, regulate sympathetic drive and a novel neurohumoral pathway mediated by both brain and circulating endogenous ouabain (EO). Circulating EO modulates ouabain-sensitive α2 Na+ pump activity and Ca2+ transporter expression and, via Na+ /Ca2+ exchange, Ca2+ homeostasis. This regulates sensitivity to sympathetic activity, Ca2+ signalling and arterial and cardiac contraction.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
| | - Ling Chen
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Frans H H Leenen
- Hypertension Unit, University of Ottawa Heart Institute, Ottawa, ON, Canada, K1Y 4W7
| | - Jerry B Lingrel
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524, USA
| | - W Gil Wier
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jin Zhang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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Ujihara Y, Iwasaki K, Takatsu S, Hashimoto K, Naruse K, Mohri S, Katanosaka Y. Induced NCX1 overexpression attenuates pressure overload-induced pathological cardiac remodelling. Cardiovasc Res 2016; 111:348-61. [PMID: 27229460 DOI: 10.1093/cvr/cvw113] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 05/22/2016] [Indexed: 11/12/2022] Open
Abstract
AIMS Although increased Na(+)/Ca(2+) exchanger 1 (NCX1) expression is observed during heart failure (HF), the pathological role of NCX1 during the progression of HF remains unclear. We examined alterations of NCX1 expression and activity in hearts after transverse aortic constriction (TAC) surgery and explored whether NCX1 influences pressure overload-induced pathological cardiac remodelling. METHODS AND RESULTS We generated novel transgenic mice in which NCX1 expression is controlled by a cardiac-specific, doxycycline (DOX)-dependent promoter. In the absence of DOX, TAC surgery caused substantial chamber dilation with a gradual decrease in contractility by 16 weeks. Cardiomyocytes showed a decline in contractility with abnormal Ca(2+) handling during excitation-contraction (E-C) coupling. Reduced NCX1 activity was observed 8 weeks after TAC and was still apparent at 17 weeks. Induced NCX1 overexpression by DOX treatment starting 8 weeks after TAC returned NCX1 activity to pre-TAC levels and prevented chamber dilation with cardiac dysfunction. DOX treatment not only upregulated NCX1 expression in TAC-operated hearts but also returned L-type Ca(2+) channel and sarcoplasmic reticulum (SR) Ca(2+) ATPase expression levels to those in sham-operated hearts. In DOX-treated myocytes, contractility, T-tubule integrity, synchrony of Ca(2+) release from the SR, and Ca(2+) handling during E-C coupling was preserved 16 weeks after TAC surgery. In addition, DOX treatment attenuated the down-regulation of survival signalling and up-regulation of apoptosis signalling 16 weeks after TAC surgery. CONCLUSION Induced overexpression of NCX1 attenuated pressure overload-induced pathological cardiac remodelling. Thus, maintaining NCX1 activity may be a potential therapeutic strategy for preventing the progression of HF.
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Affiliation(s)
- Yoshihiro Ujihara
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
| | - Keiichiro Iwasaki
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Satomi Takatsu
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Ken Hashimoto
- Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
| | - Keiji Naruse
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Satoshi Mohri
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
| | - Yuki Katanosaka
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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Jubin T, Kadam A, Saran S, Begum R. Poly (ADP-ribose) polymerase1 regulates growth and multicellularity in D. discoideum. Differentiation 2016; 92:10-23. [PMID: 27021638 DOI: 10.1016/j.diff.2016.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 03/09/2016] [Accepted: 03/15/2016] [Indexed: 12/20/2022]
Abstract
Poly (ADP-ribose) polymerase (PARP)-1 regulates various biological processes like DNA repair, cell death etc. However, the role of PARP-1 in growth and differentiation still remains elusive. The present study has been undertaken to understand the role of PARP-1 in growth and development of a unicellular eukaryote, Dictyostelium discoideum. In silico analysis demonstrates ADPRT1A as the ortholog of human PARP-1 in D. discoideum. The present study shows that ADPRT1A overexpression (A OE) led to slow growth of D. discoideum and significant population of AOE cells were in S and G2/M phase. Also, AOE cells exhibited high endogenous PARP activity, significant NAD(+) depletion and also significantly lower ADPRT1B and ADPRT2 transcript levels. Moreover, AOE cells are intrinsically stressed and also exhibited susceptibility to oxidative stress. AOE also affected development of D. discoideum predominantly streaming, aggregation and formation of early culminant which are concomitant with reports on PARP's role in D. discoideum development. In addition, under developmental stimuli, increased PARP activity was seen along with developmentally regulated transcript levels of ADPRT1A during D. discoideum multicellularity. Thus the present study suggests that PARP-1 regulates growth as well as the developmental morphogenesis of D. discoideum, thereby opening new avenues to understand the same in higher eukaryotes.
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Affiliation(s)
- Tina Jubin
- Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat 390002, India.
| | - Ashlesha Kadam
- Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat 390002, India.
| | - Shweta Saran
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Rasheedunnisa Begum
- Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat 390002, India.
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Cho GW, Altamirano F, Hill JA. Chronic heart failure: Ca(2+), catabolism, and catastrophic cell death. Biochim Biophys Acta Mol Basis Dis 2016; 1862:763-777. [PMID: 26775029 DOI: 10.1016/j.bbadis.2016.01.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 12/28/2015] [Accepted: 01/06/2016] [Indexed: 12/12/2022]
Abstract
Robust successes have been achieved in recent years in conquering the acutely lethal manifestations of heart disease. Many patients who previously would have died now survive to enjoy happy and productive lives. Nevertheless, the devastating impact of heart disease continues unabated, as the spectrum of disease has evolved with new manifestations. In light of this ever-evolving challenge, insights that culminate in novel therapeutic targets are urgently needed. Here, we review fundamental mechanisms of heart failure, both with reduced (HFrEF) and preserved (HFpEF) ejection fraction. We discuss pathways that regulate cardiomyocyte remodeling and turnover, focusing on Ca(2+) signaling, autophagy, and apoptosis. In particular, we highlight recent insights pointing to novel connections among these events. We also explore mechanisms whereby potential therapeutic approaches targeting these processes may improve morbidity and mortality in the devastating syndrome of heart failure.
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Affiliation(s)
- Geoffrey W Cho
- Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Francisco Altamirano
- Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Joseph A Hill
- Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Low-dose Exogenous Ouabain Alleviates Cardiac Lipotoxicity Through Suppressing Expression of CD36. J Cardiovasc Pharmacol 2016; 67:39-46. [DOI: 10.1097/fjc.0000000000000311] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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47
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Shattock MJ, Ottolia M, Bers DM, Blaustein MP, Boguslavskyi A, Bossuyt J, Bridge JHB, Chen-Izu Y, Clancy CE, Edwards A, Goldhaber J, Kaplan J, Lingrel JB, Pavlovic D, Philipson K, Sipido KR, Xie ZJ. Na+/Ca2+ exchange and Na+/K+-ATPase in the heart. J Physiol 2015; 593:1361-82. [PMID: 25772291 PMCID: PMC4376416 DOI: 10.1113/jphysiol.2014.282319] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/30/2014] [Indexed: 12/17/2022] Open
Abstract
This paper is the third in a series of reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on cardiac Na+/Ca2+ exchange (NCX) and Na+/K+-ATPase (NKA). While the relevance of Ca2+ homeostasis in cardiac function has been extensively investigated, the role of Na+ regulation in shaping heart function is often overlooked. Small changes in the cytoplasmic Na+ content have multiple effects on the heart by influencing intracellular Ca2+ and pH levels thereby modulating heart contractility. Therefore it is essential for heart cells to maintain Na+ homeostasis. Among the proteins that accomplish this task are the Na+/Ca2+ exchanger (NCX) and the Na+/K+ pump (NKA). By transporting three Na+ ions into the cytoplasm in exchange for one Ca2+ moved out, NCX is one of the main Na+ influx mechanisms in cardiomyocytes. Acting in the opposite direction, NKA moves Na+ ions from the cytoplasm to the extracellular space against their gradient by utilizing the energy released from ATP hydrolysis. A fine balance between these two processes controls the net amount of intracellular Na+ and aberrations in either of these two systems can have a large impact on cardiac contractility. Due to the relevant role of these two proteins in Na+ homeostasis, the emphasis of this review is on recent developments regarding the cardiac Na+/Ca2+ exchanger (NCX1) and Na+/K+ pump and the controversies that still persist in the field.
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Affiliation(s)
- Michael J Shattock
- King's College London BHF Centre of Excellence, The Rayne Institute, St Thomas' Hospital, London, SE1 7EH, UK
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Affiliation(s)
- Sujith Dassanayaka
- From the Division of Cardiovascular Medicine, Department of Medicine and Department of Physiology and Biophysics, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, KY
| | - Steven P Jones
- From the Division of Cardiovascular Medicine, Department of Medicine and Department of Physiology and Biophysics, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, KY.
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Wu J, Li D, Du L, Baldawi M, Gable ME, Askari A, Liu L. Ouabain prevents pathological cardiac hypertrophy and heart failure through activation of phosphoinositide 3-kinase α in mouse. Cell Biosci 2015; 5:64. [PMID: 26587223 PMCID: PMC4652409 DOI: 10.1186/s13578-015-0053-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 11/03/2015] [Indexed: 11/14/2022] Open
Abstract
Background
Use of low doses of digitalis to prevent the development of heart failure was advocated decades ago, but conflicting results of early animal studies dissuaded further research on this issue. Recent discoveries of digitalis effects on cell signal pathways prompted us to reexamine the possibility of this prophylactic action of digitalis. The specific aim of the present study was to determine if subinotropic doses of ouabain would prevent pressure overload-induced cardiac remodeling in the mouse by activating phosphoinositide 3-kinase α (PI3Kα). Results Studies were done on an existing transgenic mouse deficient in cardiac PI3Kα (p85-KO) but with normal cardiac contractility, a control mouse (Con), and on cultured adult cardiomyocytes. In Con myocytes, but not in p85-KO myocytes, ouabain activated PI3Kα and Akt, and caused cell growth. This occurred at low ouabain concentrations that did not activate the EGFR-Src/Ras/Raf/ERK cascade. Con and p85-KO mice were subjected to transverse aortic constriction (TAC) for 8 weeks. A subinotropic dose of ouabain (50 µg/kg/day) was constantly administrated by osmotic mini-pumps for the first 4 weeks. All mice were monitored by echocardiography throughout. Ouabain early treatment attenuated TAC-induced cardiac hypertrophy and fibrosis, and improved cardiac function in TAC-operated Con mice but not in TAC-operated p85-KO mice. TAC downregulated α2-isoform of Na+/K+-ATPase but not its α1-isoform in Con hearts, and ouabain treatment prevented the downregulation of α2-isoform. TAC-induced reduction of α2-isoform did not occur in p85-KO hearts. Conclusions Our results show that (a) safe doses of ouabain prevent or delay cardiac remodeling of pressure overloaded mouse heart; and (b) these prophylactic effects are due to ouabain binding to α2-isoform resulting in the selective activation of PI3Kα. Our findings also suggest that potential prophylactic use of digitalis for prevention of heart failure in man deserves serious consideration. Electronic supplementary material The online version of this article (doi:10.1186/s13578-015-0053-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jian Wu
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, 3000 Arlington Ave., MS 1010, Toledo, OH 43614 USA ; Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA USA
| | - Daxiang Li
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, 3000 Arlington Ave., MS 1010, Toledo, OH 43614 USA ; State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, People's Republic of China
| | - Lingling Du
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, 3000 Arlington Ave., MS 1010, Toledo, OH 43614 USA
| | - Mustafa Baldawi
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, 3000 Arlington Ave., MS 1010, Toledo, OH 43614 USA
| | - Marjorie E Gable
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, 3000 Arlington Ave., MS 1010, Toledo, OH 43614 USA
| | - Amir Askari
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, 3000 Arlington Ave., MS 1010, Toledo, OH 43614 USA
| | - Lijun Liu
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, 3000 Arlington Ave., MS 1010, Toledo, OH 43614 USA
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50
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Miller BA, Cheung JY. TRPM2 protects against tissue damage following oxidative stress and ischaemia-reperfusion. J Physiol 2015; 594:4181-91. [PMID: 26420388 DOI: 10.1113/jp270934] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 09/13/2015] [Indexed: 12/17/2022] Open
Abstract
TRPM channels are a subgroup of the transient receptor potential (TRP) channel superfamily whose members have important roles in cell proliferation and survival. TRPM2, the second subfamily member to be cloned, is expressed in many tissues including brain, heart, vasculature and haematopoietic cells. TRPM2 is activated by oxidative stress and several other extracellular signals including tumour necrosis factor α (TNF-α) and amyloid β-peptide, which increase production of ADP-ribose (ADPR). ADPR binds to the TRPM2 C-terminal NUDT9-H domain, activating the channel. Early studies support the paradigm that TRPM2 activation induces cell death by sustained Ca(2+) influx or by enhancing cytokine production, aggravating inflammation and tissue injury. However, more recent data show that for a number of physiological processes, TRPM2 is protective. TRPM2 protects lungs from endotoxin-induced injury by reducing reactive oxygen species (ROS) production by phagocytes. It protects hearts from oxidative damage after ischaemia-reperfusion or hypoxia-reoxygenation by maintaining better mitochondrial bioenergetics and by decreasing ROS. Sustained Ca(2+) entry through TRPM2 is required to maintain cellular bioenergetics and protect against hypoxia-reoxygenation injury. TRPM2 also protects neuroblastoma from moderate oxidative stress by decreasing ROS through increased levels of forkhead box transcription factor 3a (FOXO3a) and a downstream effector, superoxide dismutase 2. TRPM2 is important for tumour growth and cell survival through modulation of hypoxia-inducible transcription factor expression, mitochondrial function and mitophagy. These findings in cardiac ischaemia and in neuroblastoma suggest that TRPM2 has a basic role in sustaining mitochondrial function and in cell survival that applies to a number of physiological systems and pathophysiological processes including ischaemia-reperfusion injury.
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Affiliation(s)
- Barbara A Miller
- Departments of Pediatrics and Biochemistry & Molecular Biology, Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Joseph Y Cheung
- Center of Translational Medicine and Department of Medicine, Temple University School of Medicine, Philadelphia, PA, 19140, USA
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