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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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Ni X, Yin X, Qi C, Liu C, Chen H, Zhou Y, Ao W, Bao S, Xue J, Yang J, Dong W. Cardiotoxicity of (-)-borneol, (+)-borneol, and isoborneol in zebrafish embryos is associated with Na + /K + -ATPase and Ca 2+ -ATPase inhibition. J Appl Toxicol 2023; 43:373-386. [PMID: 36062847 DOI: 10.1002/jat.4388] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 08/08/2022] [Accepted: 08/30/2022] [Indexed: 11/10/2022]
Abstract
Borneol is an example of traditional Chinese medicine widely used in Asia. There are different isomers of chiral borneol in the market, but its toxicity and effects need further study. In this study, we used zebrafish embryos to examine the effects of exposure to three isomers of borneol [(-)-borneol, (+)-borneol, and isoborneol] on heart development and the association with Na+ /K+ -ATPase from 4 h post-fertilization (4 hpf). The results showed that the three isomers of borneol increased mortality and decreased hatching rate when the zebrafish embryo developed to 72 hpf. All three isomers of borneol (0.01-1.0 mM) significantly reduced heart rate from 48 to 120 hpf and reduced the expression of genes related to Ca2+ -ATPase (cacna1ab and cacna1da) and Na+ /K+ -ATPase (atp1b2b, atp1a3b, and atp1a2). At the same time, the three isomers of borneol significantly reduced the activities of Ca2+ -ATPase and Na+ /K+ -ATPase at 0.1 to 1.0 mM. (+)-Borneol caused the most significant reduction (p < 0.05), followed by isoborneol and (-)-borneol. Na+ /K+ -ATPase was mainly expressed in otic vesicles and protonephridium. All three isomers of borneol reduced Na+ /K+ -ATPase mRNA expression, but isoborneol was the most significant (p < 0.01). Our results indicated that (+)-borneol was the least toxic of the three isomers while the isoborneol showed the most substantial toxic effect, closely related to effects on Na+ /K+ -ATPase.
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Affiliation(s)
- Xuan Ni
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China.,School of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Xiaoyu Yin
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China
| | - Chelimuge Qi
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China
| | - Chunyu Liu
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China
| | - Hao Chen
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China
| | - Yini Zhou
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China
| | - Wuliji Ao
- Inner Mongolia Research Institute of Traditional Mongolian Medicine Engineering technology/College of Mongolian Medicine and Pharmacy, Inner Mongolia Minzu University, Tongliao, China
| | - Shuyin Bao
- The Medical College of Inner Mongolia Minzu University, Tongliao, China
| | - Jiangdong Xue
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China
| | - Jingfeng Yang
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China
| | - Wu Dong
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China
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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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Kinoshita PF, Orellana AM, Andreotti DZ, de Souza GA, de Mello NP, de Sá Lima L, Kawamoto EM, Scavone C. Consequences of the Lack of TNFR1 in Ouabain Response in the Hippocampus of C57BL/6J Mice. Biomedicines 2022; 10:biomedicines10112937. [PMID: 36428505 PMCID: PMC9688030 DOI: 10.3390/biomedicines10112937] [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: 09/09/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022] Open
Abstract
Ouabain is a cardiac glycoside that has a protective effect against neuroinflammation at low doses through Na+/K+-ATPase signaling and that can activate tumor necrosis factor (TNF) in the brain. TNF plays an essential role in neuroinflammation and regulates glutamate receptors by acting on two different receptors (tumor necrosis factor receptor 1 [TNFR1] and TNFR2) that have distinct functions and expression. The activation of constitutively and ubiquitously expressed TNFR1 leads to the expression of pro-inflammatory cytokines. Thus, this study aimed to elucidate the effects of ouabain in a TNFR1 knockout (KO) mouse model. Interestingly, the hippocampus of TNFR1 KO mice showed a basal increase in both TNFR2 membrane expression and brain-derived neurotrophic factor (BDNF) release, suggesting a compensatory mechanism. Moreover, ouabain activated TNF-α-converting enzyme/a disintegrin and metalloprotease 17 (TACE/ADAM17), decreased N-methyl-D-aspartate (NMDA) receptor subunit 2A (NR2A) expression, and induced anxiety-like behavior in both genotype animals, independent of the presence of TNFR1. However, ouabain induced an increase in interleukin (IL)-1β in the hippocampus, a decrease in IL-6 in serum, and an increase in NMDA receptor subunit 1 (NR1) only in wild-type (WT) mice, indicating that TNFR1 or TNFR2 expression may be important for some effects of ouabain. Collectively, our results indicate a connection between ouabain signaling and TNFR1, with the effect of ouabain partially dependent on TNFR1.
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Affiliation(s)
- Paula Fernanda Kinoshita
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Ana Maria Orellana
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Diana Zukas Andreotti
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Giovanna Araujo de Souza
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Natalia Prudente de Mello
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Larissa de Sá Lima
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Elisa Mitiko Kawamoto
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Cristoforo Scavone
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Correspondence:
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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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Wang H, Liu C, Zhang X, Xiu T, Li P, Zhang W, Zhang W, Wang X, Liu Z, Tang B. Simultaneous fluorescence imaging of Golgi O 2•- and Golgi H 2O 2 in mice with hypertension. Biosens Bioelectron 2022; 213:114480. [PMID: 35738216 DOI: 10.1016/j.bios.2022.114480] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/01/2022] [Accepted: 06/09/2022] [Indexed: 11/17/2022]
Abstract
Hypertensive cardiovascular disease is a persistent threat to public health. Elucidating the pathogenesis of hypertension is expected to provide more highly targeted therapies for patients. To date, reactive oxygen species (ROS) induced endothelial nitric oxide synthase (eNOS) uncoupling are generally considered to be common phenomena in hypertension. However, the critical factor contribute to persistent eNOS uncoupling remains poorly understood. Herein, we established a fluorescence probe, GolROS, for the multicolored and simultaneous detection of Golgi O2•- and H2O2 in situ. We successfully detected increases in Golgi ROS levels in hypertensive mice and evaluated the pharmaceutical effects of various antihypertensive drugs. More importantly, we identified the ROS post-transcriptional modification sites on dihydrofolate reductase (DHFR). Altogether, we propose a novel therapeutic target for hypertension, which will promote the development of new antihypertensive drugs, and also developed an ideal fluorescence probe to study in situ Golgi O2•- and H2O2 changes in various biochemical processes.
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Affiliation(s)
- Hui Wang
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China.
| | - Cuifang Liu
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China
| | - Xiaoting Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China
| | - Tiancong Xiu
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China
| | - Ping Li
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China.
| | - Wei Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China
| | - Wen Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China
| | - Xin Wang
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China
| | - Zhenzhen Liu
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China
| | - Bo Tang
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Minis-try of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institutes of Biomedical Sciences, Shandong Normal University, Jinan, 250014, People's Republic of China.
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Liu J, Tian J, Sodhi K, Shapiro JI. The Na/K-ATPase Signaling and SGLT2 Inhibitor-Mediated Cardiorenal Protection: A Crossed Road? J Membr Biol 2021; 254:513-529. [PMID: 34297135 PMCID: PMC8595165 DOI: 10.1007/s00232-021-00192-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/06/2021] [Indexed: 12/17/2022]
Abstract
In different large-scale clinic outcome trials, sodium (Na+)/glucose co-transporter 2 (SGLT2) inhibitors showed profound cardiac- and renal-protective effects, making them revolutionary treatments for heart failure and kidney disease. Different theories are proposed according to the emerging protective effects other than the original purpose of glucose-lowering in diabetic patients. As the ATP-dependent primary ion transporter providing the Na+ gradient to drive other Na+-dependent transporters, the possible role of the sodium–potassium adenosine triphosphatase (Na/K-ATPase) as the primary ion transporter and its signaling function is not explored.
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Affiliation(s)
- Jiang Liu
- Department of Biomedical Sciences, JCE School of Medicine, Marshall University, Huntington, WV, USA.
| | - Jiang Tian
- Department of Biomedical Sciences, JCE School of Medicine, Marshall University, Huntington, WV, USA
| | - Komal Sodhi
- Department of Surgery, JCE School of Medicine, Marshall University, Huntington, WV, USA
| | - Joseph I Shapiro
- Departments of Medicine, JCE School of Medicine, Marshall University, Huntington, WV, USA
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Na,K-ATPase α4, and Not Na,K-ATPase α1, is the Main Contributor to Sperm Motility, But its High Ouabain Binding Affinity Site is Not Required for Male Fertility in Mice. J Membr Biol 2021; 254:549-561. [PMID: 34129092 DOI: 10.1007/s00232-021-00181-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 04/28/2021] [Indexed: 01/05/2023]
Abstract
Mammalian sperm express two Na,K-ATPase (NKA) isoforms, Na,K-ATPase α4 (NKAα4) and Na,K-ATPase α1 (NKAα1). While NKAα4 is critical to sperm motility, the role of NKAα1 in sperm movement remains unknown. We determined this here using a genetic and pharmacological approach, modifying the affinity of NKAα1 and NKAα4 for the inhibitor ouabain to selectively block the function of each isoform. Sperm from wild-type (WT) mice (naturally containing ouabain-resistant NKAα1 and ouabain-sensitive NKAα4) and three newly generated mouse lines, expressing both NKAα1 and NKAα4 ouabain resistant (OR), ouabain sensitive (OS), and with their ouabain affinity switched (SW) were used. All mouse lines produced normal sperm numbers and were fertile. All sperm types showed NKAα isoform expression levels and activity comparable to WT, and kinetics for ouabain inhibition confirming the expected changes in ouabain affinity for each NKA isoform. Ouabain at 1 μM, which only block ouabain-sensitive NKA, significantly inhibited total, progressive, and hyperactivated sperm motility in WT and OS, but had no significant effect on OR or SW sperm. Higher ouabain (1 mM), which inhibits both ouabain-sensitive and ouabain-resistant NKA, had little additional effect on sperm motility in all mouse lines, including the OR and SW. A similar pattern was found for the effect of ouabain on sperm intracellular sodium ([Na+]i). These results indicate that NKAα4, but not NKAα1 is the main contributor to sperm motility and that the ouabain affinity site in NKA is not an essential requirement for male fertility.
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Boguslavskyi A, Tokar S, Prysyazhna O, Rudyk O, Sanchez-Tatay D, Lemmey HA, Dora KA, Garland CJ, Warren HR, Doney A, Palmer CN, Caulfield MJ, Vlachaki Walker J, Howie J, Fuller W, Shattock MJ. Phospholemman Phosphorylation Regulates Vascular Tone, Blood Pressure, and Hypertension in Mice and Humans. Circulation 2021; 143:1123-1138. [PMID: 33334125 PMCID: PMC7969167 DOI: 10.1161/circulationaha.119.040557] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 12/09/2020] [Indexed: 11/24/2022]
Abstract
BACKGROUND Although it has long been recognized that smooth muscle Na/K ATPase modulates vascular tone and blood pressure (BP), the role of its accessory protein phospholemman has not been characterized. The aim of this study was to test the hypothesis that phospholemman phosphorylation regulates vascular tone in vitro and that this mechanism plays an important role in modulation of vascular function and BP in experimental models in vivo and in humans. METHODS In mouse studies, phospholemman knock-in mice (PLM3SA; phospholemman [FXYD1] in which the 3 phosphorylation sites on serines 63, 68, and 69 are mutated to alanines), in which phospholemman is rendered unphosphorylatable, were used to assess the role of phospholemman phosphorylation in vitro in aortic and mesenteric vessels using wire myography and membrane potential measurements. In vivo BP and regional blood flow were assessed using Doppler flow and telemetry in young (14-16 weeks) and old (57-60 weeks) wild-type and transgenic mice. In human studies, we searched human genomic databases for mutations in phospholemman in the region of the phosphorylation sites and performed analyses within 2 human data cohorts (UK Biobank and GoDARTS [Genetics of Diabetes Audit and Research in Tayside]) to assess the impact of an identified single nucleotide polymorphism on BP. This single nucleotide polymorphism was expressed in human embryonic kidney cells, and its effect on phospholemman phosphorylation was determined using Western blotting. RESULTS Phospholemman phosphorylation at Ser63 and Ser68 limited vascular constriction in response to phenylephrine. This effect was blocked by ouabain. Prevention of phospholemman phosphorylation in the PLM3SA mouse profoundly enhanced vascular responses to phenylephrine both in vitro and in vivo. In aging wild-type mice, phospholemman was hypophosphorylated, and this correlated with the development of aging-induced essential hypertension. In humans, we identified a nonsynonymous coding variant, single nucleotide polymorphism rs61753924, which causes the substitution R70C in phospholemman. In human embryonic kidney cells, the R70C mutation prevented phospholemman phosphorylation at Ser68. This variant's rare allele is significantly associated with increased BP in middle-aged men. CONCLUSIONS These studies demonstrate the importance of phospholemman phosphorylation in the regulation of vascular tone and BP and suggest a novel mechanism, and therapeutic target, for aging-induced essential hypertension in humans.
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Affiliation(s)
- Andrii Boguslavskyi
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Sergiy Tokar
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Oleksandra Prysyazhna
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Olena Rudyk
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - David Sanchez-Tatay
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Hamish A.L. Lemmey
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Kim A. Dora
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Christopher J. Garland
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Helen R. Warren
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Alexander Doney
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Colin N.A. Palmer
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Mark J. Caulfield
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Julia Vlachaki Walker
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Jacqueline Howie
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - William Fuller
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
| | - Michael J. Shattock
- British Heart Foundation Centre of Research Excellence, King’s College London, United Kingdom (A.B., S.T., O.P., O.R., D.S.-T., M.J.S.). Clinical Pharmacology, The William Harvey Research Institute (O.P., H.R.W., M.J.C.), National Institute for Health Research, Biomedical Research Centre (H.R.W., M.J.C.), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom. Department of Pharmacology, University of Oxford, United Kingdom (H.A.L.L., K.A.D., C.J.G.). Medicines Monitoring Unit, School of Medicine (A.D.), Division of Cardiovascular and Diabetes Medicine (C.N.A.), University of Dundee, United Kingdom. Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom (J.V.W., J.H., W.F.)
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10
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Skogestad J, Aronsen JM, Tovsrud N, Wanichawan P, Hougen K, Stokke MK, Carlson CR, Sjaastad I, Sejersted OM, Swift F. Coupling of the Na+/K+-ATPase to Ankyrin B controls Na+/Ca2+ exchanger activity in cardiomyocytes. Cardiovasc Res 2020; 116:78-90. [PMID: 30949686 DOI: 10.1093/cvr/cvz087] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/22/2019] [Accepted: 04/03/2019] [Indexed: 01/28/2023] Open
Abstract
AIMS Ankyrin B (AnkB) is an adaptor protein that assembles Na+/K+-ATPase (NKA) and Na+/Ca2+ exchanger (NCX) in the AnkB macromolecular complex. Loss-of-function mutations in AnkB cause the AnkB syndrome in humans, characterized by ventricular arrhythmias and sudden cardiac death. It is unclear to what extent NKA binding to AnkB allows regulation of local Na+ and Ca2+ domains and hence NCX activity. METHODS AND RESULTS To investigate the role of NKA binding to AnkB in cardiomyocytes, we synthesized a disruptor peptide (MAB peptide) and its AnkB binding ability was verified by pulldown experiments. As opposed to control, the correlation between NKA and NCX currents was abolished in adult rat ventricular myocytes dialyzed with MAB peptide, as well as in cardiomyocytes from AnkB+/- mice. Disruption of NKA from AnkB (with MAB peptide) increased NCX-sensed cytosolic Na+ concentration, reduced Ca2+ extrusion through NCX, and increased frequency of Ca2+ sparks and Ca2+ waves without concomitant increase in Ca2+ transient amplitude or SR Ca2+ load, suggesting an effect in local Ca2+ domains. Selective inhibition of the NKAα2 isoform abolished both the correlation between NKA and NCX currents and the increased rate of Ca2+ sparks and waves following NKA/AnkB disruption, suggesting that an AnkB/NKAα2/NCX domain controls Ca2+ fluxes in cardiomyocytes. CONCLUSION NKA binding to AnkB allows ion regulation in a local domain, and acute disruption of the NKA/AnkB interaction using disruptor peptides lead to increased rate of Ca2+ sparks and waves. The functional effects were mediated through the NKAα2 isoform. Disruption of the AnkB/NKA/NCX domain could be an important pathophysiological mechanism in the AnkB syndrome.
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Affiliation(s)
- Jonas Skogestad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - Nils Tovsrud
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Pimthanya Wanichawan
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Karina Hougen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Mathis Korseberg Stokke
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Cathrine Rein Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Ole Mathias Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Fredrik Swift
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway.,Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
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11
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Tapia-Castillo A, Guanzon D, Palma C, Lai A, Barros E, Allende F, Vecchiola A, Fardella CE, Salomón C, Carvajal CA. Downregulation of exosomal miR-192-5p and miR-204-5p in subjects with nonclassic apparent mineralocorticoid excess. J Transl Med 2019; 17:392. [PMID: 31775784 PMCID: PMC6880399 DOI: 10.1186/s12967-019-02143-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 11/15/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The "nonclassic" apparent mineralocorticoid excess (NC-AME) has been identified in approximately 7% of general population. This phenotype is characterized by low plasma renin activity (PRA), high serum cortisol (F) to cortisone (E) ratio, low cortisone, high Fractional Excretion of potassium (FEK) and normal-elevated systolic blood pressure (SBP). An early detection and/or identification of novel biomarkers of this phenotype could avoid the progression or future complications leading to arterial hypertension. Isolation of extracellular vesicles, such as exosomes, in specific biofluids support the identification of tissue-specific RNA and miRNA, which may be useful as novel biomarkers. Our aim was to identify miRNAs within urinary exosomes associated to the NC-AME phenotype. METHODS We perform a cross-sectional study in a primary care cohort of 127 Chilean subjects. We measured BP, serum cortisol, cortisone, aldosterone, PRA. According to the previous reported, a subgroup of subjects was classified as NC-AME (n = 10). Urinary exosomes were isolated and miRNA cargo was sequenced by Illumina-NextSeq-500. RESULTS We found that NC-AME subjects had lower cortisone (p < 0.0001), higher F/E ratio (p < 0.0001), lower serum potassium (p = 0.009) and higher FEK 24 h (p = 0.03) than controls. We found miR-204-5p (fold-change = 0.115; p 0.001) and miR-192-5p (fold-change = 0.246; p 0.03) are both significantly downregulated in NC-AME. miR-192-5p expression was correlated with PRA (r = 0.45; p 0.028) and miR-204-5p expression with SBP (r = - 0.48, p 0.027) and F/E ratio (r = - 0.48; p 0.026). CONCLUSIONS These findings could support a potential role of these miRNAs as regulators and novel biomarkers of the NC-AME phenotype.
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Affiliation(s)
- Alejandra Tapia-Castillo
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Diagonal Paraguay 362, piso 4, Santiago, 8330077, Chile
- Centro Traslacional de Endocrinología (CETREN-UC), Pontificia Universidad Católica de Chile, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy (IMII-ICM), Santiago, Chile
| | - Dominic Guanzon
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
| | - Carlos Palma
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
| | - Andrew Lai
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
| | - Eric Barros
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Diagonal Paraguay 362, piso 4, Santiago, 8330077, Chile
- Millennium Institute on Immunology and Immunotherapy (IMII-ICM), Santiago, Chile
| | - Fidel Allende
- Centro Traslacional de Endocrinología (CETREN-UC), Pontificia Universidad Católica de Chile, Santiago, Chile
- Department of Clinical Laboratories, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Andrea Vecchiola
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Diagonal Paraguay 362, piso 4, Santiago, 8330077, Chile
- Centro Traslacional de Endocrinología (CETREN-UC), Pontificia Universidad Católica de Chile, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy (IMII-ICM), Santiago, Chile
| | - Carlos E Fardella
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Diagonal Paraguay 362, piso 4, Santiago, 8330077, Chile
- Centro Traslacional de Endocrinología (CETREN-UC), Pontificia Universidad Católica de Chile, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy (IMII-ICM), Santiago, Chile
| | - Carlos Salomón
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
- Department of Clinical Biochemistry and Immunology, Faculty of Pharmacy, University of Concepción, Concepción, Chile
| | - Cristian A Carvajal
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Diagonal Paraguay 362, piso 4, Santiago, 8330077, Chile.
- Centro Traslacional de Endocrinología (CETREN-UC), Pontificia Universidad Católica de Chile, Santiago, Chile.
- Millennium Institute on Immunology and Immunotherapy (IMII-ICM), Santiago, Chile.
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12
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Zhang J, Wang Y, Chen L, Wier WG, Blaustein MP. Na +/Ca 2+ exchanger overexpression in smooth muscle augments cytosolic Ca 2+ in femoral arteries of living mice. Am J Physiol Heart Circ Physiol 2019; 316:H298-H310. [PMID: 30461304 PMCID: PMC6397384 DOI: 10.1152/ajpheart.00185.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 11/05/2018] [Accepted: 11/15/2018] [Indexed: 11/22/2022]
Abstract
Plasma membrane Na+/Ca2+ exchanger-1 (NCX1) helps regulate the cytosolic Ca2+ concentration ([Ca2+]CYT) in arterial myocytes. NCX1 mediates both Ca2+ entry and exit and tends to promote net Ca2+ entry in partially constricted arteries. Mean blood pressure (telemetry) is elevated by ≈10 mmHg in transgenic (TG) mice that overexpress NCX1 specifically in smooth muscle. We tested the hypothesis that NCX1 overexpression mediates Ca2+ gain and elevated [Ca2+]CYT in exposed femoral arteries that also express the Ca2+ biosensor exogenous myosin light chain kinase. [Ca2+]CYT and the NCX1-dependent (SEA0400-sensitive) component, ≈15% of total basal constriction in controls, were increased in TG arteries, but constrictions to phenylephrine and ANG II were comparable in TG and control arteries. Normalized phenylephrine dose-response curves and constriction to 30 and 300 ng/kg iv ANG II were virtually identical in control and TG arteries. ANG II-evoked constrictions, superimposed on elevated basal tone, accounted for the larger blood pressure responses to ANG II in TG arteries. TG and control mouse arteries fit the same pCa-constriction relationship over a wide range of pCa (≈125-500 nM). Vasodilation to acetylcholine, normalized to passive diameter, was also comparable in TG and control arteries, implying normal endothelial function. TG artery Na+ nitroprusside (nitric oxide donor)-induced dilations were, however, shifted to lower Na+ nitroprusside concentrations, indicating that TG myocyte vasodilator mechanisms were augmented. Maximum arterial dilation was comparable in TG and control mice, although passive diameter was ≈6-7% smaller in TG mice. The changes in TG arteries were apparently largely functional rather than structural, despite the congenital hypertension. NEW & NOTEWORTHY Smooth muscle Na+/Ca2+ exchanger-1 transgene overexpression (TG mice) increases femoral artery basal cytosolic Ca2+ concentration ([Ca2+]CYT) and tone in vivo and raises blood pressure. Arterial constriction to phenylephrine and angiotensin II are normal but superimposed on the augmented basal [Ca2+]CYT and tone (constriction) in TG mouse arteries. Similar effects in resistance arteries would explain the elevated blood pressure. Acetylcholine-induced vasodilation is unimpaired, implying a normal endothelium, but TG arteries are hypersensitive to sodium nitroprusside.
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Affiliation(s)
- Jin Zhang
- Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland
| | - Youhua Wang
- Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland
- Department of Physical Education, Shaanxi Normal University , Xi'an, Shaanxi , China
| | - Ling Chen
- Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland
- Department of Medicine, University of Maryland School of Medicine , Baltimore, Maryland
| | - W Gil Wier
- Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland
| | - 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
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13
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The Na,K-ATPase-Dependent Src Kinase Signaling Changes with Mesenteric Artery Diameter. Int J Mol Sci 2018; 19:ijms19092489. [PMID: 30142894 PMCID: PMC6164810 DOI: 10.3390/ijms19092489] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 08/17/2018] [Accepted: 08/21/2018] [Indexed: 01/09/2023] Open
Abstract
Inhibition of the Na,K-ATPase by ouabain potentiates vascular tone and agonist-induced contraction. These effects of ouabain varies between different reports. In this study, we assessed whether the pro-contractile effect of ouabain changes with arterial diameter and the molecular mechanism behind it. Rat mesenteric small arteries of different diameters (150–350 µm) were studied for noradrenaline-induced changes of isometric force and intracellular Ca2+ in smooth muscle cells. These functional changes were correlated to total Src kinase and Src phosphorylation assessed immunohistochemically. High-affinity ouabain-binding sites were semi-quantified with fluorescent ouabain. We found that potentiation of noradrenaline-sensitivity by ouabain correlates positively with an increase in arterial diameter. This was not due to differences in intracellular Ca2+ responses but due to sensitization of smooth muscle cell contractile machinery to Ca2+. This was associated with ouabain-induced Src activation, which increases with increasing arterial diameter. Total Src expression was similar in arteries of different diameters but the density of high-affinity ouabain binding sites increased with increasing arterial diameters. We suggested that ouabain binding induces more Src kinase activity in mesenteric small arteries with larger diameter leading to enhanced sensitization of the contractile machinery to Ca2+.
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14
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Floyd RV, Mobasheri A, Wray S. Gestation changes sodium pump isoform expression, leading to changes in ouabain sensitivity, contractility, and intracellular calcium in rat uterus. Physiol Rep 2018; 5. [PMID: 29208689 PMCID: PMC5727280 DOI: 10.14814/phy2.13527] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 11/24/2022] Open
Abstract
Developmental and tissue‐specific differences in isoforms allow Na+, K+‐ATPase function to be tightly regulated, as they control sensitivity to ions and inhibitors. Uterine contraction relies on the activity of the Na+, K+ATPase, which creates ionic gradients that drive excitation‐contraction coupling. It is unknown whether Na+, K+ATPase isoforms are regulated throughout pregnancy or whether they have a direct role in modulating uterine contractility. We hypothesized that gestation‐dependent differential expression of isoforms would affect contractile responses to Na+, K+ATPase α subunit inhibition with ouabain. Our aims were therefore: (1) to determine the gestation‐dependent expression of mRNA transcripts, protein abundance and tissue distribution of Na+, K+ATPase isoforms in myometrium; (2) to investigate the functional effects of differential isoform expression via ouabain sensitivity; and (3) if changes in contractile responses can be explained by changes in intracellular [Ca2+]. Changes in abundance and distribution of the Na+, K+ATPase α, β and FXYD1 and 2 isoforms, were studied in rat uterus from nonpregnant, and early, mid‐, and term gestation. All α, β subunit isoforms (1,2,3) and FXYD1 were detected but FXYD2 was absent. The α1 and β1 isoforms were unchanged throughout pregnancy, whereas α2 and α3 significant decreased at term while β2 and FXYD1 significantly increased from mid‐term onwards. These changes in expression correlated with increased functional sensitivity to ouabain, and parallel changes in intracellular Ca2+, measured with Indo‐1. In conclusion, gestation induces specific regulatory changes in expression of Na+, K+ATPase isoforms in the uterus which influence contractility and may be related to the physiological requirements for successful pregnancy and delivery.
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Affiliation(s)
- Rachel V Floyd
- The Department of Molecular and Cellular Physiology, University of Liverpool, Liverpool, United Kingdom
| | - Ali Mobasheri
- Department of Veterinary Preclinical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Susan Wray
- The Department of Molecular and Cellular Physiology, University of Liverpool, Liverpool, United Kingdom
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15
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Buffolo F, Monticone S, Tetti M, Mulatero P. Primary aldosteronism in the primary care setting. Curr Opin Endocrinol Diabetes Obes 2018; 25:155-159. [PMID: 29629943 DOI: 10.1097/med.0000000000000408] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE OF REVIEW The aim of the present manuscript is to provide an overview of the most updated studies on the prevalence of primary aldosteronism in primary care and to compare these figures with the actual rate of diagnosis in clinical practice and with the prevalence of primary aldosteronism in specific subgroup of patients. RECENT FINDINGS Over the last 20 years the clinical spectrum of low renin hypertension and primary aldosteronism has changed dramatically. Once considered only in the presence of severe hypertension and hypokalemia, it is now well known that primary aldosteronism is not uncommon even in patients with mild forms of hypertension and/or normokalemia. Moreover, recent evidence points toward a large proportion of normotensive study participants as being affected by subclinical primary aldosteronism, which represents a strong risk factor for incident hypertension. Moreover, primary aldosteronism patients are exposed to an increased risk of cardio and cerebrovascular events and metabolic comorbidities compared with patients affected by essential hypertension. Disappointingly, primary aldosteronism remains a largely underdiagnosed and undertreated disorder. SUMMARY These recent findings further highlight the importance of widening the spectrum of patients who should be screened for primary aldosteronism, to reduce the cardiovascular risk associated with this medical condition.
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Affiliation(s)
- Fabrizio Buffolo
- Division of Internal Medicine and Hypertension Unit, Department of Medical Sciences, University of Torino, Turin, Italy
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16
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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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17
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Blaustein MP. The pump, the exchanger, and the holy spirit: origins and 40-year evolution of ideas about the ouabain-Na + pump endocrine system. Am J Physiol Cell Physiol 2017; 314:C3-C26. [PMID: 28971835 DOI: 10.1152/ajpcell.00196.2017] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Two prescient 1953 publications set the stage for the elucidation of a novel endocrine system: Schatzmann's report that cardiotonic steroids (CTSs) are all Na+ pump inhibitors, and Szent-Gyorgi's suggestion that there is an endogenous "missing screw" in heart failure that CTSs like digoxin may replace. In 1977 I postulated that an endogenous Na+ pump inhibitor acts as a natriuretic hormone and simultaneously elevates blood pressure (BP) in salt-dependent hypertension. This hypothesis was based on the idea that excess renal salt retention promoted the secretion of a CTS-like hormone that inhibits renal Na+ pumps and salt reabsorption. The hormone also inhibits arterial Na+ pumps, elevates myocyte Na+ and promotes Na/Ca exchanger-mediated Ca2+ gain. This enhances vasoconstriction and arterial tone-the hallmark of hypertension. Here I describe how those ideas led to the discovery that the CTS-like hormone is endogenous ouabain (EO), a key factor in the pathogenesis of hypertension and heart failure. Seminal observations that underlie the still-emerging picture of the EO-Na+ pump endocrine system in the physiology and pathophysiology of multiple organ systems are summarized. Milestones include: 1) cloning the Na+ pump isoforms and physiological studies of mutated pumps in mice; 2) discovery that Na+ pumps are also EO-triggered signaling molecules; 3) demonstration that ouabain, but not digoxin, is hypertensinogenic; 4) elucidation of EO's roles in kidney development and cardiovascular and renal physiology and pathophysiology; 5) discovery of "brain ouabain", a component of a novel hypothalamic neuromodulatory pathway; and 6) finding that EO and its brain receptors modulate behavior and learning.
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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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18
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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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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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20
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Lima DB, Valente RC, Capella MAM. Ouabain-induced alterations in ABCB1 of mesenteric lymph nodes and thymocytes of rats and mice. Oncol Lett 2017; 12:5275-5280. [PMID: 28105236 DOI: 10.3892/ol.2016.5366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 06/27/2016] [Indexed: 11/06/2022] Open
Abstract
Ouabain is a glycoside with immunomodulating properties, and recent studies have suggested its use in adjuvant therapy for cancer treatment. Ouabain is known to modulate the immune system in vitro, and previous studies have revealed that ouabain can modulate the expression and activity of ABCB1, a protein associated with multidrug resistance present in immune system. Therefore, the present study investigated alterations in the expression and activity of ABCB1 in the thymi, peripheral blood monocytes and lymph nodes of Wistar rats and Swiss mice treated acutely or chronically with ouabain. A decrease of almost 45% in the monocyte count and an increase of 55% in the basophil count were observed. A significant decrease (75% reduction) in the amount of cells with ABCB1 activity was found in the thymocytes of ouabain-treated rats and mice. The possible implications of these results for cancer treatment are discussed.
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Affiliation(s)
- Daniel Boff Lima
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil
| | - Raphael Carmo Valente
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil
| | - Marcia Alves Marques Capella
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil
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21
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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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22
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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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23
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Iatrino R, Manunta P, Zagato L. Salt Sensitivity: Challenging and Controversial Phenotype of Primary Hypertension. Curr Hypertens Rep 2016; 18:70. [DOI: 10.1007/s11906-016-0677-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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24
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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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25
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26
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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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27
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Liu M, Feng LX, Sun P, Liu W, Wu WY, Jiang BH, Yang M, Hu LH, Guo DA, Liu X. A Novel Bufalin Derivative Exhibited Stronger Apoptosis-Inducing Effect than Bufalin in A549 Lung Cancer Cells and Lower Acute Toxicity in Mice. PLoS One 2016; 11:e0159789. [PMID: 27459387 PMCID: PMC4961401 DOI: 10.1371/journal.pone.0159789] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 07/06/2016] [Indexed: 12/22/2022] Open
Abstract
BF211 is a synthetic molecule derived from bufalin (BF). The apoptosis-inducing effect of BF211 was stronger than that of BF while the acute toxicity of BF211 was much lower than that of BF. BF211 exhibited promising concentration-dependent anti-cancer effects in nude mice inoculated with A549 cells in vivo. The growth of A549 tumor xenografts was almost totally blocked by treatment with BF211 at 6 mg/kg. Notably, BF and BF211 exhibited differences in their binding affinity and kinetics to recombinant proteins of the α subunits of Na+/K+-ATPase. Furthermore, there was a difference in the effects of BF or BF211 on inhibiting the activity of porcine cortex Na+/K+-ATPase and in their time-dependent effects on intracellular Ca2+ levels in A549 cells. The time-dependent effects of BF or BF211 on the activation of Src, which was mediated by the Na+/K+-ATPase signalosome, in A549 cells were also different. Both BF and BF211 could induce apoptosis-related cascades, such as activation of caspase-3 and the cleavage of PARP (poly ADP-ribose polymerase) in A549 cells, in a concentration-dependent manner; however, the effects of BF211 on apoptosis-related cascades was stronger than that of BF. The results of the present study supported the importance of binding to the Na+/K+-ATPase α subunits in the mechanism of cardiac steroids and also suggested the possibility of developing new cardiac steroids with a stronger anti-cancer activity and lower toxicity as new anti-cancer agents.
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Affiliation(s)
- Miao Liu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
| | - Li-Xing Feng
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
| | - Peng Sun
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
| | - Wang Liu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
| | - Wan-Ying Wu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
| | - Bao-Hong Jiang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
| | - Min Yang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
| | - Li-Hong Hu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
- * E-mail: (LH); (DG); (XL)
| | - De-An Guo
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
- * E-mail: (LH); (DG); (XL)
| | - Xuan Liu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China
- * E-mail: (LH); (DG); (XL)
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28
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Affiliation(s)
- John M Hamlyn
- From the Departments of Physiology (J.M.H., M.P.B.) and Medicine (M.P.B.), University of Maryland School of Medicine, Baltimore.
| | - Mordecai P Blaustein
- From the Departments of Physiology (J.M.H., M.P.B.) and Medicine (M.P.B.), University of Maryland School of Medicine, Baltimore.
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Matchkov VV, Krivoi II. Specialized Functional Diversity and Interactions of the Na,K-ATPase. Front Physiol 2016; 7:179. [PMID: 27252653 PMCID: PMC4879863 DOI: 10.3389/fphys.2016.00179] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/04/2016] [Indexed: 12/22/2022] Open
Abstract
Na,K-ATPase is a protein ubiquitously expressed in the plasma membrane of all animal cells and vitally essential for their functions. A specialized functional diversity of the Na,K-ATPase isozymes is provided by molecular heterogeneity, distinct subcellular localizations, and functional interactions with molecular environment. Studies over the last decades clearly demonstrated complex and isoform-specific reciprocal functional interactions between the Na,K-ATPase and neighboring proteins and lipids. These interactions are enabled by a spatially restricted ion homeostasis, direct protein-protein/lipid interactions, and protein kinase signaling pathways. In addition to its "classical" function in ion translocation, the Na,K-ATPase is now considered as one of the most important signaling molecules in neuronal, epithelial, skeletal, cardiac and vascular tissues. Accordingly, the Na,K-ATPase forms specialized sub-cellular multimolecular microdomains which act as receptors to circulating endogenous cardiotonic steroids (CTS) triggering a number of signaling pathways. Changes in these endogenous cardiotonic steroid levels and initiated signaling responses have significant adaptive values for tissues and whole organisms under numerous physiological and pathophysiological conditions. This review discusses recent progress in the studies of functional interactions between the Na,K-ATPase and molecular microenvironment, the Na,K-ATPase-dependent signaling pathways and their significance for diversity of cell function.
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Affiliation(s)
| | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University St. Petersburg, Russia
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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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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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Manoharan P, Radzyukevich TL, Hakim Javadi H, Stiner CA, Landero Figueroa JA, Lingrel JB, Heiny JA. Phospholemman is not required for the acute stimulation of Na⁺-K⁺-ATPase α₂-activity during skeletal muscle fatigue. Am J Physiol Cell Physiol 2015; 309:C813-22. [PMID: 26468207 DOI: 10.1152/ajpcell.00205.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 09/08/2015] [Indexed: 11/22/2022]
Abstract
The Na(+)-K(+)-ATPase α2-isoform in skeletal muscle is rapidly stimulated during muscle use and plays a critical role in fatigue resistance. The acute mechanisms that stimulate α2-activity are not completely known. This study examines whether phosphorylation of phospholemman (PLM/FXYD1), a regulatory subunit of Na(+)-K(+)-ATPase, plays a role in the acute stimulation of α2 in working muscles. Mice lacking PLM (PLM KO) have a normal content of the α2-subunit and show normal exercise capacity, in contrast to the greatly reduced exercise capacity of mice that lack α2 in the skeletal muscles. Nerve-evoked contractions in vivo did not induce a change in total PLM or PLM phosphorylated at Ser63 or Ser68, in either WT or PLM KO. Isolated muscles of PLM KO mice maintain contraction and resist fatigue as well as wild type (WT). Rb(+) transport by the α2-Na(+)-K(+)-ATPase is stimulated to the same extent in contracting WT and contracting PLM KO muscles. Phosphorylation of sarcolemmal membranes prepared from WT but not PLM KO skeletal muscles stimulates the activity of both α1 and α2 in a PLM-dependent manner. The stimulation occurs by an increase in Na(+) affinity without significant change in Vmax and is more effective for α1 than α2. These results demonstrate that phosphorylation of PLM is capable of stimulating the activity of both isozymes in skeletal muscle; however, contractile activity alone is not sufficient to induce PLM phosphorylation. Importantly, acute stimulation of α2, sufficient to support exercise and oppose fatigue, does not require PLM or its phosphorylation.
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Affiliation(s)
- Palanikumar Manoharan
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio
| | - Tatiana L Radzyukevich
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio; and
| | - Hesamedin Hakim Javadi
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio; and
| | - Cory A Stiner
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio
| | | | - Jerry B Lingrel
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio
| | - Judith A Heiny
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio; and
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Chen L, Song H, Wang Y, Lee JC, Kotlikoff MI, Pritchard TJ, Paul RJ, Zhang J, Blaustein MP. Arterial α2-Na+ pump expression influences blood pressure: lessons from novel, genetically engineered smooth muscle-specific α2 mice. Am J Physiol Heart Circ Physiol 2015. [PMID: 26209057 DOI: 10.1152/ajpheart.00430.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Arterial myocytes express α1-catalytic subunit isoform Na(+) pumps (75-80% of total), which are ouabain resistant in rodents, and high ouabain affinity α2-Na(+) pumps. Mice with globally reduced α2-pumps (but not α1-pumps), mice with mutant ouabain-resistant α2-pumps, and mice with a smooth muscle (SM)-specific α2-transgene (α2 (SM-Tg)) that induces overexpression all have altered blood pressure (BP) phenotypes. We generated α2 (SM-DN) mice with SM-specific α2 (not α1) reduction (>50%) using nonfunctional dominant negative (DN) α2. We compared α2 (SM-DN) and α2 (SM-Tg) mice to controls to determine how arterial SM α2-pumps affect vasoconstriction and BP. α2 (SM-DN) mice had elevated basal mean BP (mean BP by telemetry: 117 ± 4 vs. 106 ± 1 mmHg, n = 7/7, P < 0.01) and enhanced BP responses to chronic ANG II infusion (240 ng·kg(-1)·min(-1)) and high (6%) NaCl. Several arterial Ca(2+) transporters, including Na(+)/Ca(2+) exchanger 1 (NCX1) and sarcoplasmic reticulum and plasma membrane Ca(2+) pumps [sarco(endo)plasmic reticulum Ca(2+)-ATPase 2 (SERCA2) and plasma membrane Ca(2+)-ATPase 1 (PMCA1)], were also reduced (>50%). α2 (SM-DN) mouse isolated small arteries had reduced myogenic reactivity, perhaps because of reduced Ca(2+) transporter expression. In contrast, α2 (SM-Tg) mouse aortas overexpressed α2 (>2-fold), NCX1, SERCA2, and PMCA1 (43). α2 (SM-Tg) mice had reduced basal mean BP (104 ± 1 vs. 109 ± 2 mmHg, n = 15/9, P < 0.02) and attenuated BP responses to chronic ANG II (300-400 ng·kg(-1)·min(-1)) with or without 2% NaCl but normal myogenic reactivity. NCX1 expression was inversely related to basal BP in SM-α2 engineered mice but was directly related in SM-NCX1 engineered mice. NCX1, which usually mediates arterial Ca(2+) entry, and α2-Na(+) pumps colocalize at plasma membrane-sarcoplasmic reticulum junctions and functionally couple via the local Na(+) gradient to help regulate cell Ca(2+). Altered Ca(2+) transporter expression in SM-α2 engineered mice apparently compensates to minimize Ca(2+) overload (α2 (SM-DN)) or depletion (α2 (SM-Tg)) and attenuate BP changes. In contrast, Ca(2+) transporter upregulation, observed in many rodent hypertension models, should enhance Ca(2+) entry and signaling and contribute significantly to BP elevation.
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Affiliation(s)
- Ling Chen
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Hong Song
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Youhua Wang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jane C Lee
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Michael I Kotlikoff
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Tracy J Pritchard
- College of Nursing, College of Medicine, University of Cincinnati, Cincinnati, Ohio; and
| | - Richard J Paul
- Department of Molecular and Cell Physiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Jin Zhang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - 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;
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Leenen FHH, Hou X, Wang HW, Ahmad M. Enhanced expression of epithelial sodium channels causes salt-induced hypertension in mice through inhibition of the α2-isoform of Na+, K+-ATPase. Physiol Rep 2015; 3:3/5/e12383. [PMID: 25991719 PMCID: PMC4463818 DOI: 10.14814/phy2.12383] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Knockout of the Nedd4-2 gene in mice results in overexpression of epithelial sodium channels (ENaC) on the plasma membrane in the kidney, choroid plexus and brain nuclei. These mice exhibit enhanced pressor responses to CSF [Na(+)] as well as dietary salt-induced hypertension which both can be blocked by central infusion of the ENaC blocker benzamil. Functional studies suggest that ENaC activation in the CNS results in release of endogenous ouabain (EO) and inhibition of the α2-isoform of Na(+), K(+)-ATPase. To test this concept more specifically, we studied Nedd4-2(-/-) mice expressing the ouabain-resistant α2R/R-isoform of Na(+), K(+)-ATPase. Intracerebroventricular (icv) infusion of Na(+)-rich aCSF (225 mmol/L Na(+) at 0.4 μL/min) increased MAP by 10-15 mmHg in wild-type mice and by 25-30 mmHg in Nedd4-2(-/-) mice, but by only ~5 mmHg in α2R/R and in α2R/R/Nedd4-2(-/-) mice. Icv infusion of EO-binding Fab fragments also blocked the BP response in Nedd4-2(-/-) mice. In Nedd4-2(-/-) mice, 8% high-salt diet increased MAP by 25-30 mmHg, but in α2R/R/Nedd4-2(-/-) mice, it increased by only 5-10 mmHg. In contrast, Nedd4-2(-/-) or α2R/R did not affect the hypertension caused by sc infusion of Ang II. These findings substantiate the concept that enhanced ENaC activity causes salt-induced pressor responses mainly through EO inhibiting the α2-isoform of Na(+), K(+)-ATPase in the brain.
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Affiliation(s)
| | - Xiaohong Hou
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Hong-Wei Wang
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Monir Ahmad
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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35
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Blaustein MP. Reply to "Letter to the editor: 'Why isn't clinical experience with ouabain more widely accepted?'". Am J Physiol Heart Circ Physiol 2014; 307:H1264-5. [PMID: 25320336 DOI: 10.1152/ajpheart.00571.2014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Mordecai P Blaustein
- Departments of Physiology and Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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Hodes A, Lichtstein D. Natriuretic hormones in brain function. Front Endocrinol (Lausanne) 2014; 5:201. [PMID: 25506340 PMCID: PMC4246887 DOI: 10.3389/fendo.2014.00201] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 11/12/2014] [Indexed: 01/11/2023] Open
Abstract
Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain. In this review, the established information on the biosynthesis, release and function of NH is discussed, with particular focus on their role in brain function. The available literature on the expression patterns of each of the NH and their receptors in the brain is summarized, followed by the evidence for their roles in modulating brain function. Although numerous open questions exist regarding this issue, the available data support the notion that NH participate in the central regulation of BP, neuroprotection, satiety, and various psychiatric conditions, including anxiety, addiction, and depressive disorders. In addition, the interactions between the different NH in the periphery and the brain are discussed.
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Affiliation(s)
- Anastasia Hodes
- Faculty of Medicine, Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - David Lichtstein
- Faculty of Medicine, Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Jerusalem, Israel
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Ghadhanfar E, Al-Bader M, Turcani M. Wistar rats resistant to the hypertensive effects of ouabain exhibit enhanced cardiac vagal activity and elevated plasma levels of calcitonin gene-related peptide. PLoS One 2014; 9:e108909. [PMID: 25279791 PMCID: PMC4184851 DOI: 10.1371/journal.pone.0108909] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 08/28/2014] [Indexed: 01/03/2023] Open
Abstract
Ouabain is a cardiac glycoside produced in the adrenal glands and hypothalamus. It affects the function of all cells by binding to Na+/K+-ATPase. Several lines of evidence suggest that endogenous ouabain could be involved in the pathogenesis of essential (particularly, salt-sensitive) hypertension. However, information regarding the postulated hypertensive effect of the long-term administration of low-dose exogenous ouabain is inconsistent. This study was designed to help settle this controversy through the use of telemetric monitoring of arterial blood pressure and to elucidate the ouabain-induced alterations that could either promote or prevent hypertension. Ouabain (63 and 324 µg/kg/day) was administered subcutaneously to male Wistar rats. Radiotelemetry was used to monitor blood pressure, heart rate and measures of cardiovascular variability and baroreflex sensitivity. The continuous administration of ouabain for 3 months did not elevate arterial blood pressure. The low-frequency power of systolic pressure variability, urinary excretion of catecholamines, and cardiovascular response to restraint stress and a high-salt diet as well as the responsiveness to α1-adrenergic stimulation were all unaltered by ouabain administration, suggesting that the activity of the sympathetic nervous system was not increased. However, surrogate indices of cardiac vagal nerve activity based on heart rate variability were elevated. Molecular remodeling in mesenteric arteries that could support the development of hypertension (increased expression of the genes for the Na+/Ca2+ exchanger and Na+/K+-ATPase α2 isoform) was not evident. Instead, the plasma level of vasodilatory calcitonin gene-related peptide (CGRP) significantly rose from 55 (11, SD) in the control group to 89 (20, SD) pg/ml in the ouabain-treated rats (PTukey's = 18.10(-5)). These data show that long-term administration of exogenous ouabain does not necessarily cause hypertension in rodents. The augmented parasympathetic activity and elevated plasma level of CGRP could be linked to the missing hypertensive effect of ouabain administration.
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Affiliation(s)
- Elham Ghadhanfar
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Maie Al-Bader
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Marian Turcani
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
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Hamlyn JM, Linde CI, Gao J, Huang BS, Golovina VA, Blaustein MP, Leenen FHH. Neuroendocrine humoral and vascular components in the pressor pathway for brain angiotensin II: a new axis in long term blood pressure control. PLoS One 2014; 9:e108916. [PMID: 25275393 PMCID: PMC4183521 DOI: 10.1371/journal.pone.0108916] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 08/26/2014] [Indexed: 11/29/2022] Open
Abstract
Central nervous system (CNS) administration of angiotensin II (Ang II) raises blood pressure (BP). The rise in BP reflects increased sympathetic outflow and a slower neuromodulatory pressor mechanism mediated by CNS mineralocorticoid receptors (MR). We investigated the hypothesis that the sustained phase of hypertension is associated also with elevated circulating levels of endogenous ouabain (EO), and chronic stimulation of arterial calcium transport proteins including the sodium-calcium exchanger (NCX1), the type 6 canonical transient receptor potential protein (TRPC6), and the sarcoplasmic reticulum calcium ATPase (SERCA2). Wistar rats received a chronic intra-cerebroventricular infusion of vehicle (C) or Ang II (A, 2.5 ng/min, for 14 days) alone or combined with the MR blocker, eplerenone (A+E, 5 µg/day), or the aldosterone synthase inhibitor, FAD286 (A+F, 25 µg/day). Conscious mean BP increased (P<0.05) in A (123±4 mm Hg) vs all other groups. Blood, pituitary and adrenal samples were taken for EO radioimmunoassay (RIA), and aortas for NCX1, TRPC6 and SERCA2 immunoblotting. Central infusion of Ang II raised plasma EO (0.58±0.08 vs C 0.34±0.07 nM (P<0.05), but not in A + E and A + F groups as confirmed by off-line liquid chromatography (LC)-RIA and LC-multistage mass spectrometry. Two novel isomers of EO were elevated by Ang II; the second less polar isomer increased >50-fold in the A+F group. Central Ang II increased arterial expression of NCX1, TRPC6 and SERCA2 (2.6, 1.75 and 3.7-fold, respectively; P<0.01)) but not when co-infused with E or F. Adrenal and pituitary EO were unchanged. We conclude that brain Ang II activates a CNS-humoral axis involving plasma EO. The elevated EO reprograms peripheral ion transport pathways known to control arterial Na+ and Ca2+ homeostasis; this increases contractility and augments sympathetic effects. The new axis likely contributes to the chronic pressor effect of brain Ang II.
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Affiliation(s)
- John M. Hamlyn
- Department of Physiology, University of Maryland Baltimore, Baltimore, Maryland, United States of America
- * E-mail:
| | - Cristina I. Linde
- Department of Physiology, University of Maryland Baltimore, Baltimore, Maryland, United States of America
| | - Junjie Gao
- Department of Physiology, University of Maryland Baltimore, Baltimore, Maryland, United States of America
| | - Bing S. Huang
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Vera A. Golovina
- Department of Physiology, University of Maryland Baltimore, Baltimore, Maryland, United States of America
| | - Mordecai P. Blaustein
- Department of Physiology, University of Maryland Baltimore, Baltimore, Maryland, United States of America
- Department of Medicine, University of Maryland Baltimore, Baltimore, Maryland, United States of America
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Affiliation(s)
- Mordecai P Blaustein
- Departments of Physiology and Medicine and the Center for Heart, Hypertension and Kidney Disease, University of Maryland School of Medicine, Baltimore, Maryland
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Abstract
Ouabain (Oua)-induced hypertension in rodents provides a model to study cardiovascular changes associated with human hypertension. We examined vascular function in rats after a long-term treatment with Oua. Systolic blood pressure was measured by tail-cuff plethysmography in male Sprague-Dawley rats treated with Oua (≈ 25 µg/d) or placebo for 8 weeks. Blood pressure increased in Oua-treated animals, reaching 30% above baseline systolic blood pressure after 7 weeks. At the end of treatment, vascular responses were studied in mesenteric resistance arteries (MRAs) by wire myography. Contraction to potassium chloride in intact and denuded arteries showed greater sensitivity in Oua-treated animals. Contraction to phenylephrine and relaxation to acetylcholine were similar between groups with a lower response to sodium nitroprusside in Oua-treated arteries. Sensitivity to endothelin-1 was higher in Oua-treated arteries. Na⁺-K⁺ ATPase activity was decreased in MRAs from Oua-treated animals, whereas protein expression of the Na⁺-K⁺ ATPase α₂ isoform was increased in heart and unchanged in mesenteric artery. Preincubation with indomethacin (10⁻⁵ M) or Nω-nitro-L-arginine methyl ester (10⁻⁴ M) abolished the differences in potassium chloride response and Na⁺-K⁺ ATPase activity. Changes in MRAs are consistent with enhanced vascular smooth muscle cell reactivity, a contributor to the increased vascular tone observed in this model of hypertension.
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Song H, Karashima E, Hamlyn JM, Blaustein MP. Ouabain-digoxin antagonism in rat arteries and neurones. J Physiol 2013; 592:941-69. [PMID: 24344167 DOI: 10.1113/jphysiol.2013.266866] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
'Classic' cardiotonic steroids (CTSs) such as digoxin and ouabain selectively inhibit Na+, K+ -ATPase (the Na+ pump) and, via Na+ / Ca2+ exchange (NCX), exert cardiotonic and vasotonic effects. CTS action is more complex than previously thought: prolonged subcutaneous administration of ouabain, but not digoxin, induces hypertension, and digoxin antagonizes ouabain's hypertensinogenic effect. We studied the acute interactions between CTSs in two indirect assays of Na+ pump function: myogenic tone (MT) in isolated, pressurized rat mesenteric small arteries, and Ca2+ signalling in primary cultured rat hippocampal neurones. The 'classic' CTSs (0.3-10 nm) behaved as 'agonists': all increased MT70 (MT at 70 mmHg) and augmented glutamate-evoked Ca2+ (Fura-2) signals. We then tested one CTS in the presence of another. Most CTSs could be divided into ouabain-like (ouabagenin, dihydroouabain (DHO), strophanthidin) or digoxin-like CTS (digoxigenin, digitoxin, bufalin). Within each group, the CTSs were synergistic, but ouabain-like and digoxin-like CTSs antagonized one another in both assays: For example, the ouabain-evoked (3 nm) increases in MT70 and neuronal Ca2+ signals were both greatly attenuated by the addition of 10 nm digoxin or 10 nm bufalin, and vice versa. Rostafuroxin (PST2238), a digoxigenin derivative that displaces 3H-ouabain from Na+, K+ -ATPase, and attenuates some forms of hypertension, antagonized the effects of ouabain, but not digoxin. SEA0400, a Na+ / Ca2+ exchanger (NCX) blocker, antagonized the effects of both ouabain and digoxin. CTSs bind to the α subunit of pump αβ protomers. Analysis of potential models suggests that, in vivo, Na+ pumps function as tetraprotomers ((αβ)4) in which the binding of a single CTS to one protomer blocks all pumping activity. The paradoxical ability of digoxin-like CTSs to reactivate the ouabain-inhibited complex can be explained by de-oligomerization of the tetrameric state. The interactions between these common CTSs may be of considerable therapeutic relevance.
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Affiliation(s)
- Hong Song
- Department of Physiology, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD 21201, USA. or
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Prasad MK, Bhalla K, Pan ZH, O’Connell JR, Weder AB, Chakravarti A, Tian B, Chang YPC. A polymorphic 3'UTR element in ATP1B1 regulates alternative polyadenylation and is associated with blood pressure. PLoS One 2013; 8:e76290. [PMID: 24098465 PMCID: PMC3788127 DOI: 10.1371/journal.pone.0076290] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/22/2013] [Indexed: 12/31/2022] Open
Abstract
Although variants in many genes have previously been shown to be associated with blood pressure (BP) levels, the molecular mechanism underlying these associations are mostly unknown. We identified a multi-allelic T-rich sequence (TRS) in the 3’UTR of ATP1B1 that varies in length and sequence composition (T22-27 and T12GT 3GT6). The 3’UTR of ATP1B1 contains 2 functional polyadenylation signals and the TRS is downstream of the proximal polyadenylation site (A2). Therefore, we hypothesized that alleles of this TRS might influence ATP1B1 expression by regulating alternative polyadenylation. In vitro, the T12GT 3GT6 allele increases polyadenylation at the A2 polyadenylation site as compared to the T23 allele. Consistent with our hypothesis, the relative abundance of the A2-polyadenylated ATP1B1 mRNA was higher in human kidneys with at least one copy of the T12GT 3GT6 allele than in those lacking this allele. The T12GT 3GT6 allele is also associated with higher systolic BP (beta = 3.3 mmHg, p = 0.014) and diastolic BP (beta = 2.4 mmHg, p = 0.003) in a European-American population. Therefore, we have identified a novel multi-allelic TRS in the 3’UTR of ATP1B1 that is associated with higher BP and may mediate its effect by regulating the polyadenylation of the ATP1B1 mRNA.
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Affiliation(s)
- Megana K. Prasad
- Division of Endocrinology, Diabetes and Nutrition, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Kavita Bhalla
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Zhen Hua Pan
- Department of Biochemistry & Molecular Biology, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, New Jersey, United States of America
| | - Jeffrey R. O’Connell
- Division of Endocrinology, Diabetes and Nutrition, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Alan B. Weder
- Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Aravinda Chakravarti
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Bin Tian
- Department of Biochemistry & Molecular Biology, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, New Jersey, United States of America
| | - Yen-Pei C. Chang
- Division of Endocrinology, Diabetes and Nutrition, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Zhang LN, Li JX, Hao L, Sun YJ, Xie YH, Wu SM, Liu L, Chen XL, Gao ZB. Crosstalk between dopamine receptors and the Na⁺/K⁺-ATPase (review). Mol Med Rep 2013; 8:1291-9. [PMID: 24065247 DOI: 10.3892/mmr.2013.1697] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 09/05/2013] [Indexed: 11/06/2022] Open
Abstract
Dopamine (DA) receptors, which belong to the G protein-coupled receptor family, are the target of ~50% of all modern medicinal drugs and constitute a large and diverse class of proteins whose primary function is to transduce extracellular stimuli into intracellular signals. Na+/K+-ATPase (NKA) is ubiquitous and crucial for the maintenance of intracellular ion homeostasis and excitability. Furthermore, it plays a critical role in diverse effects, including clinical cardiotonic and cardioprotective effects, ischemic preconditioning in the brain, natriuresis, lung edema clearance and other processes. NKA regulation is of physiological and pharmacological importance and has species- and tissue-specific variations. The activation of DA receptors regulates NKA expression/activity and trafficking in various tissues and cells, for example in the kidney, lung, intestine, brain, non-pigmented ciliary epithelium and the vascular bed. DA receptor-mediated regulation of NKA mediates a diverse range of cellular responses and includes endocytosis/exocytosis, phosphorylation/dephosphorylation of the α subunit of NKA and multiple signaling pathways, including phosphatidylinositol (PI)-phospholipase C/protein kinase (PK) C, cAMP/PKA, PI3K, adaptor protein 2, tyrosine phosphatase and mitogen-activated protein kinase/extracellular signal-regulated protein kinase. Furthermore, in brain and HEK293T cells, D1 and D2 receptors exist in a complex with NKA. Among D1 and D2 receptors and NKA, regulations are reciprocal, which leads to crosstalk between DA receptors and NKA. In the present study, the current understanding of signaling mechanisms responsible for the crosstalk between DA receptors and NKA, as well as with specific consequent functions, is reviewed.
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Affiliation(s)
- Li-Nan Zhang
- Department of Pharmacy, College of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018, P.R. China
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Blanco G, Wallace DP. Novel role of ouabain as a cystogenic factor in autosomal dominant polycystic kidney disease. Am J Physiol Renal Physiol 2013; 305:F797-812. [PMID: 23761677 DOI: 10.1152/ajprenal.00248.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The classic role of the Na-K-ATPase is that of a primary active transporter that utilizes cell energy to establish and maintain transmembrane Na(+) and K(+) gradients to preserve cell osmotic stability, support cell excitability, and drive secondary active transport. Recent studies have revealed that Na-K-ATPase located within cholesterol-containing lipid rafts serves as a receptor for cardiotonic steroids, including ouabain. Traditionally, ouabain was viewed as a toxin produced only in plants, and it was used in relatively high concentrations to experimentally block the pumping action of the Na-K-ATPase. However, the new and unexpected role of the Na-K-ATPase as a signal transducer revealed a novel facet for ouabain in the regulation of a myriad of cell functions, including cell proliferation, hypertrophy, apoptosis, mobility, and metabolism. The seminal discovery that ouabain is endogenously produced in mammals and circulates in plasma has fueled the interest in this endogenous molecule as a potentially important hormone in normal physiology and disease. In this article, we review the role of the Na-K-ATPase as an ion transporter in the kidney, the experimental evidence for ouabain as a circulating hormone, the function of the Na-K-ATPase as a signal transducer that mediates ouabain's effects, and novel results for ouabain-induced Na-K-ATPase signaling in cystogenesis of autosomal dominant polycystic kidney disease.
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Affiliation(s)
- Gustavo Blanco
- Dept. of Molecular and Integrative Physiology, 3901 Rainbow Blvd., Kansas City, KS 66160.
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Abstract
PURPOSE OF REVIEW Endogenous cardiotonic steroids (CTS) exert long-term effects on salt and blood pressure homeostasis. Here we discuss recent observations on mechanisms of salt sensitivity that involve endogenous ouabain and novel pathways in the brain and discuss their possible relationship to arterial and renal function in hypertension. RECENT FINDINGS Chronic elevation of brain sodium promotes sustained hypertension mediated by central endogenous ouabain and the Na(+) pump α-2 catalytic subunit. The intermediary pressor mechanism in the brain involves aldosterone biosynthesis, activation of mineralocorticoid receptors and increased epithelial sodium channel activity. In the periphery, elevated plasma CTS raise contractility and blood pressure by augmentation of sympathetic nerve responses, increasing arterial Ca(2+) signaling and blunting nitric oxide production in the renal medulla and collecting ducts. SUMMARY Endogenous ouabain in the brain appears to play a critical role in salt sensitivity and hypertension. In the periphery, the J-shaped relationship of plasma endogenous ouabain in response to short-term changes in salt balance in humans raises the possibility that endogenous ouabain contributes to the increased risk of adverse cardiovascular events associated with both low and high salt intakes.
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Kirshenbaum GS, Dawson N, Mullins JGL, Johnston TH, Drinkhill MJ, Edwards IJ, Fox SH, Pratt JA, Brotchie JM, Roder JC, Clapcote SJ. Alternating hemiplegia of childhood-related neural and behavioural phenotypes in Na+,K+-ATPase α3 missense mutant mice. PLoS One 2013; 8:e60141. [PMID: 23527305 PMCID: PMC3603922 DOI: 10.1371/journal.pone.0060141] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 02/21/2013] [Indexed: 12/29/2022] Open
Abstract
Missense mutations in ATP1A3 encoding Na+,K+-ATPase α3 have been identified as the primary cause of alternating hemiplegia of childhood (AHC), a motor disorder with onset typically before the age of 6 months. Affected children tend to be of short stature and can also have epilepsy, ataxia and learning disability. The Na+,K+-ATPase has a well-known role in maintaining electrochemical gradients across cell membranes, but our understanding of how the mutations cause AHC is limited. Myshkin mutant mice carry an amino acid change (I810N) that affects the same position in Na+,K+-ATPase α3 as I810S found in AHC. Using molecular modelling, we show that the Myshkin and AHC mutations display similarly severe structural impacts on Na+,K+-ATPase α3, including upon the K+ pore and predicted K+ binding sites. Behavioural analysis of Myshkin mice revealed phenotypic abnormalities similar to symptoms of AHC, including motor dysfunction and cognitive impairment. 2-DG imaging of Myshkin mice identified compromised thalamocortical functioning that includes a deficit in frontal cortex functioning (hypofrontality), directly mirroring that reported in AHC, along with reduced thalamocortical functional connectivity. Our results thus provide validation for missense mutations in Na+,K+-ATPase α3 as a cause of AHC, and highlight Myshkin mice as a starting point for the exploration of disease mechanisms and novel treatments in AHC.
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Affiliation(s)
- Greer S. Kirshenbaum
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Neil Dawson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Jonathan G. L. Mullins
- Institute of Life Science, College of Medicine, Swansea University, Swansea, United Kingdom
| | - Tom H. Johnston
- Division of Brain, Imaging and Behaviour – Systems Neuroscience, Toronto Western Research Institute, Toronto, Ontario, Canada
| | - Mark J. Drinkhill
- Division of Cardiovascular and Neuronal Remodelling, Leeds Institute for Genetics, Health and Therapeutics, University of Leeds, Leeds, United Kingdom
| | - Ian J. Edwards
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Susan H. Fox
- Division of Brain, Imaging and Behaviour – Systems Neuroscience, Toronto Western Research Institute, Toronto, Ontario, Canada
| | - Judith A. Pratt
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Jonathan M. Brotchie
- Division of Brain, Imaging and Behaviour – Systems Neuroscience, Toronto Western Research Institute, Toronto, Ontario, Canada
| | - John C. Roder
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Steven J. Clapcote
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- * E-mail:
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Rindler TN, Lasko VM, Nieman ML, Okada M, Lorenz JN, Lingrel JB. Knockout of the Na,K-ATPase α2-isoform in cardiac myocytes delays pressure overload-induced cardiac dysfunction. Am J Physiol Heart Circ Physiol 2013; 304:H1147-58. [PMID: 23436327 DOI: 10.1152/ajpheart.00594.2012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The α2-isoform of the Na,K-ATPase (α2) is the minor isoform of the Na,K-ATPase expressed in the cardiovascular system and is thought to play a critical role in the regulation of cardiovascular hemodynamics. However, the organ system/cell type expressing α2 that is required for this regulation has not been fully defined. The present study uses a heart-specific knockout of α2 to further define the tissue-specific role of α2 in the regulation of cardiovascular hemodynamics. To accomplish this, we developed a mouse model using the Cre/loxP system to generate a tissue-specific knockout of α2 in the heart using β-myosin heavy chain Cre. We have achieved a 90% knockout of α2 expression in the heart of the knockout mice. Interestingly, the heart-specific knockout mice exhibit normal basal cardiac function and systolic blood pressure, and in addition, these mice develop ACTH-induced hypertension in response to ACTH treatment similar to control mice. Surprisingly, the heart-specific knockout mice display delayed onset of cardiac dysfunction compared with control mice in response to pressure overload induced by transverse aortic constriction; however, the heart-specific knockout mice deteriorated to control levels by 9 wk post-transverse aortic constriction. These results suggest that heart expression of α2 does not play a role in the regulation of basal cardiovascular function or blood pressure; however, heart expression of α2 plays a role in the hypertrophic response to pressure overload. This study further emphasizes that the tissue localization of α2 determines its unique roles in the regulation of cardiovascular function.
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Affiliation(s)
- Tara N Rindler
- Department of Molecular Genetics, Biochemistry, and Microbiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
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Song H, Thompson SM, Blaustein MP. Nanomolar ouabain augments Ca2+ signalling in rat hippocampal neurones and glia. J Physiol 2013; 591:1671-89. [PMID: 23297310 DOI: 10.1113/jphysiol.2012.248336] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Linkage of certain neurological diseases to Na(+) pump mutations and some mood disorders to altered Na(+) pump function has renewed interest in brain Na(+) pumps. We tested nanomolar ouabain on Ca(2+) signalling (fura-2) in rat hippocampal neurone-astrocyte co-cultures. The neurones and astrocytes express Na(+) pumps with a high-ouabain-affinity catalytic subunit (α3 and α2, respectively); both also express pumps with a ouabain-resistant α1 subunit. Neurones and astrocytes were identified by immunocytochemistry and by stimulation; 3-4 μM L-glutamate (Glu) and 3 μM carbachol (CCh) evoked rapid Ca(2+) transients only in neurones, and small, delayed transients in some astrocytes, whereas 0.5-1 μM ATP evoked Ca(2+) transients only in astrocytes. Both cell types responded to 5-10 μM Glu or ATP. The signals evoked by 3-4 μM Glu in neurones were markedly inhibited by 3-10 μm MPEP (blocks metabotropic glutamate receptor mGluR5) and 10 μm LY341495 (non-selective mGluR blocker), but not by 80 μm AP5 (NMDA receptor blocker) or by selective block of mGluR1 or mGluR2. Pre-incubation (0.5-10 min) with 1-10 nm ouabain (EC50 < 1 nm) augmented Glu- and CCh-evoked signals in neurones. This augmentation was abolished by a blocker of the Na(+)-Ca(2+) exchanger, SEA0400 (300 nm). Ouabain (3 nm) pre-incubation also augmented 10 μM cyclopiazonic acid plus 10 mm caffeine-evoked release of Ca(2+) from the neuronal endoplasmic reticulum (ER). The implication is that nanomolar ouabain inhibits α3 Na(+) pumps, increases (local) intracellular Na(+), and promotes Na(+)-Ca(2+) exchanger-mediated Ca(2+) gain and increased storage in the adjacent ER. Ouabain (3 nm) also increased ER Ca(2+) release and enhanced 0.5 μM ATP-evoked transients in astrocytes; these effects were mediated by α2 Na(+) pumps. Thus, nanomolar ouabain may strongly influence synaptic transmission in the brain as a result of its actions on the high-ouabain-affinity Na(+) pumps in both neurones and astrocytes. The significance of these effects is heightened by the evidence that ouabain is endogenous in mammals.
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Affiliation(s)
- Hong Song
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Zulian A, Linde CI, Pulina MV, Baryshnikov SG, Papparella I, Hamlyn JM, Golovina VA. Activation of c-SRC underlies the differential effects of ouabain and digoxin on Ca(2+) signaling in arterial smooth muscle cells. Am J Physiol Cell Physiol 2012. [PMID: 23195071 DOI: 10.1152/ajpcell.00337.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiotonic steroids (CTS) of the strophanthus and digitalis families have opposing effects on long-term blood pressure (BP). This implies hitherto unrecognized divergent signaling pathways for these CTS. Prolonged ouabain treatment upregulates Ca(2+) entry via Na(+)/Ca(2+) exchanger-1 (NCX1) and TRPC6 gene-encoded receptor-operated channels in mesenteric artery smooth muscle cells (ASMCs) in vivo and in vitro. Here, we test the effects of digoxin on Ca(2+) entry and signaling in ASMC. In contrast to ouabain treatment, the in vivo administration of digoxin (30 μg·kg(-1)·day(-1) for 3 wk) did not raise BP and had no effect on resting cytolic free Ca(2+) concentration ([Ca(2+)](cyt)) or phenylephrine-induced Ca(2+) signals in isolated ASMCs. Expression of transporters in the α2 Na(+) pump-NCX1-TRPC6 Ca(2+) signaling pathway was not altered in arteries from digoxin-treated rats. Upregulated α2 Na(+) pumps and a phosphorylated form of the c-SRC protein kinase (pY419-Src, ~4.5-fold) were observed in ASMCs from rats treated with ouabain but not digoxin. Moreover, in primary cultured ASMCs from normal rats, treatment with digoxin (100 nM, 72 h) did not upregulate NCX1 and TRPC6 but blocked the ouabain-induced upregulation of these transporters. Pretreatment of ASMCs with the c-Src inhibitor PP2 (1 μM; 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine) but not its inactive analog eliminated the effect of ouabain on NCX1 and TRPC6 expression and ATP-induced Ca(2+) entry. Thus, in contrast to ouabain, the interaction of digoxin with α2 Na(+) pumps is unable to activate c-Src phosphorylation and upregulate the downstream NCX1-TRPC6 Ca(2+) signaling pathway in ASMCs. The inability of digoxin to upregulate c-Src may underlie its inability to raise long-term BP.
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Affiliation(s)
- Alessandra Zulian
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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