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Vagin O, Tokhtaeva E, Larauche M, Davood J, Marcus EA. Helicobacter pylori-Induced Decrease in Membrane Expression of Na,K-ATPase Leads to Gastric Injury. Biomolecules 2024; 14:772. [PMID: 39062486 PMCID: PMC11274427 DOI: 10.3390/biom14070772] [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: 05/01/2024] [Revised: 06/12/2024] [Accepted: 06/26/2024] [Indexed: 07/28/2024] Open
Abstract
Helicobacter pylori is a highly prevalent human gastric pathogen that causes gastritis, ulcer disease, and gastric cancer. It is not yet fully understood how H. pylori injures the gastric epithelium. The Na,K-ATPase, an essential transporter found in virtually all mammalian cells, has been shown to be important for maintaining the barrier function of lung and kidney epithelia. H. pylori decreases levels of Na,K-ATPase in the plasma membrane of gastric epithelial cells, and the aim of this study was to demonstrate that this reduction led to gastric injury by impairing the epithelial barrier. Similar to H. pylori infection, the inhibition of Na,K-ATPase with ouabain decreased transepithelial electrical resistance and increased paracellular permeability in cell monolayers of human gastric cultured cells, 2D human gastric organoids, and gastric epithelium isolated from gerbils. Similar effects were caused by a partial shRNA silencing of Na,K-ATPase in human gastric organoids. Both H. pylori infection and ouabain exposure disrupted organization of adherens junctions in human gastric epithelia as demonstrated by E-cadherin immunofluorescence. Functional and structural impairment of epithelial integrity with a decrease in Na,K-ATPase amount or activity provides evidence that the H. pylori-induced downregulation of Na,K-ATPase plays a role in the complex mechanism of gastric disease induced by the bacteria.
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Affiliation(s)
- Olga Vagin
- Department of Pediatrics, DGSOM at UCLA, 10833 LeConte Ave., 12-383 MDCC, Los Angeles, CA 90095, USA; (O.V.); (E.T.)
- VA GLAHS 11301 Wilshire Blvd, Bldg 113, Rm 324, Los Angeles, CA 90073, USA; (M.L.); (J.D.)
| | - Elmira Tokhtaeva
- Department of Pediatrics, DGSOM at UCLA, 10833 LeConte Ave., 12-383 MDCC, Los Angeles, CA 90095, USA; (O.V.); (E.T.)
- VA GLAHS 11301 Wilshire Blvd, Bldg 113, Rm 324, Los Angeles, CA 90073, USA; (M.L.); (J.D.)
| | - Muriel Larauche
- VA GLAHS 11301 Wilshire Blvd, Bldg 113, Rm 324, Los Angeles, CA 90073, USA; (M.L.); (J.D.)
- Department of Medicine, Vatche and Tamar Manoukian Division of Digestive Diseases, DGSOM at UCLA, 650 Charles E Young Dr. S., CHS 43-276, Los Angeles, CA 90095, USA
| | - Joshua Davood
- VA GLAHS 11301 Wilshire Blvd, Bldg 113, Rm 324, Los Angeles, CA 90073, USA; (M.L.); (J.D.)
- Department of Medicine, Vatche and Tamar Manoukian Division of Digestive Diseases, DGSOM at UCLA, 650 Charles E Young Dr. S., CHS 43-276, Los Angeles, CA 90095, USA
| | - Elizabeth A. Marcus
- Department of Pediatrics, DGSOM at UCLA, 10833 LeConte Ave., 12-383 MDCC, Los Angeles, CA 90095, USA; (O.V.); (E.T.)
- VA GLAHS 11301 Wilshire Blvd, Bldg 113, Rm 324, Los Angeles, CA 90073, USA; (M.L.); (J.D.)
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2
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Contreras RG, Torres-Carrillo A, Flores-Maldonado C, Shoshani L, Ponce A. Na +/K +-ATPase: More than an Electrogenic Pump. Int J Mol Sci 2024; 25:6122. [PMID: 38892309 PMCID: PMC11172918 DOI: 10.3390/ijms25116122] [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: 03/26/2024] [Revised: 05/20/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024] Open
Abstract
The sodium pump, or Na+/K+-ATPase (NKA), is an essential enzyme found in the plasma membrane of all animal cells. Its primary role is to transport sodium (Na+) and potassium (K+) ions across the cell membrane, using energy from ATP hydrolysis. This transport creates and maintains an electrochemical gradient, which is crucial for various cellular processes, including cell volume regulation, electrical excitability, and secondary active transport. Although the role of NKA as a pump was discovered and demonstrated several decades ago, it remains the subject of intense research. Current studies aim to delve deeper into several aspects of this molecular entity, such as describing its structure and mode of operation in atomic detail, understanding its molecular and functional diversity, and examining the consequences of its malfunction due to structural alterations. Additionally, researchers are investigating the effects of various substances that amplify or decrease its pumping activity. Beyond its role as a pump, growing evidence indicates that in various cell types, NKA also functions as a receptor for cardiac glycosides like ouabain. This receptor activity triggers the activation of various signaling pathways, producing significant morphological and physiological effects. In this report, we present the results of a comprehensive review of the most outstanding studies of the past five years. We highlight the progress made regarding this new concept of NKA and the various cardiac glycosides that influence it. Furthermore, we emphasize NKA's role in epithelial physiology, particularly its function as a receptor for cardiac glycosides that trigger intracellular signals regulating cell-cell contacts, proliferation, differentiation, and adhesion. We also analyze the role of NKA β-subunits as cell adhesion molecules in glia and epithelial cells.
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Affiliation(s)
| | | | | | | | - Arturo Ponce
- Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN, Mexico City 07360, Mexico; (R.G.C.); (A.T.-C.); (C.F.-M.); (L.S.)
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3
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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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Cai L, Pessoa MT, Gao Y, Strause S, Banerjee M, Tian J, Xie Z, Pierre SV. The Na/K-ATPase α1/Src Signaling Axis Regulates Mitochondrial Metabolic Function and Redox Signaling in Human iPSC-Derived Cardiomyocytes. Biomedicines 2023; 11:3207. [PMID: 38137428 PMCID: PMC10740578 DOI: 10.3390/biomedicines11123207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/15/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
Na/K-ATPase (NKA)-mediated regulation of Src kinase, which involves defined amino acid sequences of the NKA α1 polypeptide, has emerged as a novel regulatory mechanism of mitochondrial function in metazoans. Mitochondrial metabolism ensures adequate myocardial performance and adaptation to physiological demand. It is also a critical cellular determinant of cardiac repair and remodeling. To assess the impact of the proposed NKA/Src regulatory axis on cardiac mitochondrial metabolic function, we used a gene targeting approach in human cardiac myocytes. Human induced pluripotent stem cells (hiPSC) expressing an Src-signaling null mutant (A420P) form of the NKA α1 polypeptide were generated using CRISPR/Cas9-mediated genome editing. Total cellular Na/K-ATPase activity remained unchanged in A420P compared to the wild type (WT) hiPSC, but baseline phosphorylation levels of Src and ERK1/2 were drastically reduced. Both WT and A420P mutant hiPSC readily differentiated into cardiac myocytes (iCM), as evidenced by marker gene expression, spontaneous cell contraction, and subcellular striations. Total NKA α1-3 protein expression was comparable in WT and A420P iCM. However, live cell metabolism assessed functionally by Seahorse extracellular flux analysis revealed significant reductions in both basal and maximal rates of mitochondrial respiration, spare respiratory capacity, ATP production, and coupling efficiency. A significant reduction in ROS production was detected by fluorescence imaging in live cells, and confirmed by decreased cellular protein carbonylation levels in A420P iCM. Taken together, these data provide genetic evidence for a role of NKA α1/Src in the tonic stimulation of basal mitochondrial metabolism and ROS production in human cardiac myocytes. This signaling axis in cardiac myocytes may provide a new approach to counteract mitochondrial dysfunction in cardiometabolic diseases.
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Affiliation(s)
- Liquan Cai
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Marco T. Pessoa
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Yingnyu Gao
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Sidney Strause
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Moumita Banerjee
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
- Department of Surgery, University of Kentucky, Lexington, KY 40536, USA
| | - Jiang Tian
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
- Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA
| | - Zijian Xie
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
| | - Sandrine V. Pierre
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV 25703, USA; (L.C.); (M.T.P.); (Y.G.); (S.S.); (M.B.); (J.T.); (Z.X.)
- Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA
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5
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Gurler B, Gencay G, Baloglu E. Hypoxia and HIF-1α Regulate the Activity and Expression of Na,K-ATPase Subunits in H9c2 Cardiomyoblasts. Curr Issues Mol Biol 2023; 45:8277-8288. [PMID: 37886965 PMCID: PMC10605391 DOI: 10.3390/cimb45100522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 10/08/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023] Open
Abstract
The optimal function of the Na,K-ATPase (NKA) pump is essential for the heart. In ischemic heart disease, NKA activity decreases due to the decreased expression of the pump subunits. Here, we tested whether the hypoxia-inducible transcription factor (HIF-1α), the key signaling molecule regulating the adaptation of cells to hypoxia, is involved in controlling the expression and cellular dynamics of α1- and β1-NKA isoforms and of NKA activity in in-vitro hypoxic H9c2 cardiomyoblasts. HIF-1α was silenced through adenoviral infection, and cells were kept in normoxia (19% O2) or hypoxia (1% O2) for 24 h. We investigated the mRNA and protein expression of α1-, β1-NKA using RT-qPCR and Western blot in whole-cell lysates, cell membranes, and cytoplasmic fractions after labeling the cell surface with NHS-SS-biotin and immunoprecipitation. NKA activity and intracellular ATP levels were also measured. We found that in hypoxia, silencing HIF-1α prevented the decreased mRNA expression of α1-NKA but not of β1-NKA. Hypoxia decreased the plasma membrane expression of α1-NKA and β1- NKA compared to normoxic cells. In hypoxic cells, HIF-1α silencing prevented this effect by inhibiting the internalization of α1-NKA. Total protein expression was not affected. The decreased activity of NKA in hypoxic cells was fully prevented by silencing HIF-1α independent of cellular ATP levels. This study is the first to show that in hypoxic H9c2 cardiomyoblasts, HIF-1α controls the internalization and membrane insertion of α1-NKA subunit and of NKA activity. The mechanism behind this regulation needs further investigation.
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Affiliation(s)
- Beyza Gurler
- Department of Medical Biotechnology, Institute of Health Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul 34752, Turkey;
| | - Gizem Gencay
- Department of Molecular and Translational Biomedicine, Institute of Natural and Applied Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul 34752, Turkey;
| | - Emel Baloglu
- Department of Medical Pharmacology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul 34752, Turkey
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6
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Martínez-Rendón J, Hinojosa L, Xoconostle-Cázares B, Ramírez-Pool JA, Castillo A, Cereijido M, Ponce A. Ouabain Induces Transcript Changes and Activation of RhoA/ROCK Signaling in Cultured Epithelial Cells (MDCK). Curr Issues Mol Biol 2023; 45:7538-7556. [PMID: 37754259 PMCID: PMC10528288 DOI: 10.3390/cimb45090475] [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: 07/28/2023] [Revised: 08/30/2023] [Accepted: 09/09/2023] [Indexed: 09/28/2023] Open
Abstract
Ouabain, an organic compound with the ability to strengthen the contraction of the heart muscle, was originally derived from plants. It has been observed that certain mammalian species, including humans, naturally produce ouabain, leading to its classification as a new type of hormone. When ouabain binds to Na+/K+-ATPase, it elicits various physiological effects, although these effects are not well characterized. Previous studies have demonstrated that ouabain, within the concentration range found naturally in the body (10 nmol/L), affects the polarity of epithelial cells and their intercellular contacts, such as tight junctions, adherens junctions, and gap junctional communication. This is achieved by activating signaling pathways involving cSrc and Erk1/2. To further investigate the effects of ouabain within the hormonally relevant concentration range (10 nmol/L), mRNA-seq, a high-throughput sequencing technique, was employed to identify differentially expressed transcripts. The discovery that the transcript encoding MYO9A was among the genes affected prompted an exploration of whether RhoA and its downstream effector ROCK were involved in the signaling pathways through which ouabain influences cell-to-cell contacts in epithelial cells. Supporting this hypothesis, this study reveals the following: (1) Ouabain increases the activation of RhoA. (2) Treatment with inhibitors of RhoA activation (Y27) and ROCK (C3) eliminates the enhancing effect of ouabain on the tight junction seal and intercellular communication via gap junctions. These findings further support the notion that ouabain acts as a hormone to emphasize the epithelial phenotype.
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Affiliation(s)
- Jacqueline Martínez-Rendón
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de Mexico 07360, Mexico; (J.M.-R.); (L.H.); (A.C.); (M.C.)
- Molecular Medicine Laboratory, Unidad Académica de Medicina Humana y C.S., Campus UAZ Siglo XXI-L1, Universidad Autónoma de Zacatecas, Zacatecas 98160, Mexico
| | - Lorena Hinojosa
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de Mexico 07360, Mexico; (J.M.-R.); (L.H.); (A.C.); (M.C.)
| | - Beatriz Xoconostle-Cázares
- Department of Biotechnology and Bioengineering, CINVESTAV-IPN, Ciudad de Mexico 07360, Mexico; (B.X.-C.); (J.A.R.-P.)
| | - José Abrahán Ramírez-Pool
- Department of Biotechnology and Bioengineering, CINVESTAV-IPN, Ciudad de Mexico 07360, Mexico; (B.X.-C.); (J.A.R.-P.)
| | - Aída Castillo
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de Mexico 07360, Mexico; (J.M.-R.); (L.H.); (A.C.); (M.C.)
| | - Marcelino Cereijido
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de Mexico 07360, Mexico; (J.M.-R.); (L.H.); (A.C.); (M.C.)
| | - Arturo Ponce
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de Mexico 07360, Mexico; (J.M.-R.); (L.H.); (A.C.); (M.C.)
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7
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Baloglu E. Hypoxic Stress-Dependent Regulation of Na,K-ATPase in Ischemic Heart Disease. Int J Mol Sci 2023; 24:ijms24097855. [PMID: 37175562 PMCID: PMC10177966 DOI: 10.3390/ijms24097855] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
In cardiomyocytes, regular activity of the Na,K-ATPase (NKA) and its Na/K pump activity is essential for maintaining ion gradients, excitability, propagation of action potentials, electro-mechanical coupling, trans-membrane Na+ and Ca2+ gradients and, thus, contractility. The activity of NKA is impaired in ischemic heart disease and heart failure, which has been attributed to decreased expression of the NKA subunits. Decreased NKA activity leads to intracellular Na+ and Ca2+ overload, diastolic dysfunction and arrhythmias. One signal likely related to these events is hypoxia, where hypoxia-inducible factors (HIF) play a critical role in the adaptation of cells to low oxygen tension. HIF activity increases in ischemic heart, hypertension, heart failure and cardiac fibrosis; thus, it might contribute to the impaired function of NKA. This review will mainly focus on the regulation of NKA in ischemic heart disease in the context of stressed myocardium and the hypoxia-HIF axis and argue on possible consequences of treatment.
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Affiliation(s)
- Emel Baloglu
- Department of Medical Pharmacology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Turkey
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8
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Rajanathan R, Pedersen TM, Guldbrandsen HO, Olesen LF, Thomsen MB, Bøtker HE, Matchkov VV. Augmented Ouabain-Induced Vascular Response Reduces Cardiac Efficiency in Mice with Migraine-Associated Mutation in the Na +, K +-ATPase α 2-Isoform. Biomedicines 2023; 11:biomedicines11020344. [PMID: 36830881 PMCID: PMC9953359 DOI: 10.3390/biomedicines11020344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/22/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023] Open
Abstract
Heterozygous mice (α2+/G301R mice) for the migraine-associated mutation (G301R) in the Na+,K+-ATPase α2-isoform have decreased expression of cardiovascular α2-isoform. The α2+/G301R mice exhibit a pro-contractile vascular phenotype associated with decreased left ventricular ejection fraction. However, the integrated functional cardiovascular consequences of this phenotype remain to be addressed in vivo. We hypothesized that the vascular response to α2-isoform-specific inhibition of the Na+,K+-ATPase by ouabain is augmented in α2+/G301R mice leading to reduced cardiac efficiency. Thus, we aimed to assess the functional contribution of the α2-isoform to in vivo cardiovascular function of wild-type (WT) and α2+/G301R mice. Blood pressure, stroke volume, heart rate, total peripheral resistance, arterial dP/dt, and systolic time intervals were assessed in anesthetized WT and α2+/G301R mice. To address rate-dependent cardiac changes, cardiovascular variables were compared before and after intraperitoneal injection of ouabain (1.5 mg/kg) or vehicle during atrial pacing. The α2+/G301R mice showed an enhanced ouabain-induced increase in total peripheral resistance associated with reduced efficiency of systolic development compared to WT. When the hearts were paced, ouabain reduced stroke volume in α2+/G301R mice. In conclusion, the ouabain-induced vascular response was augmented in α2+/G301R mice with consequent suppression of cardiac function.
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Affiliation(s)
- Rajkumar Rajanathan
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
- Correspondence:
| | | | | | | | - Morten B. Thomsen
- Department of Biomedical Sciences, University of Copenhagen, 1165 Copenhagen, Denmark
| | - Hans Erik Bøtker
- Department of Cardiology, Aarhus University Hospital, 8000 Aarhus, Denmark
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Blaustein MP, Gottlieb SS, Hamlyn JM, Leenen FHH. Whither digitalis? What we can still learn from cardiotonic steroids about heart failure and hypertension. Am J Physiol Heart Circ Physiol 2022; 323:H1281-H1295. [PMID: 36367691 DOI: 10.1152/ajpheart.00362.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cloning of the "Na+ pump" (Na+,K+-ATPase or NKA) and identification of a circulating ligand, endogenous ouabain (EO), a cardiotonic steroid (CTS), triggered seminal discoveries regarding EO and its NKA receptor in cardiovascular function and the pathophysiology of heart failure (HF) and hypertension. Cardiotonic digitalis preparations were a preferred treatment for HF for two centuries, but digoxin was only marginally effective in a large clinical trial (1997). This led to diminished digoxin use. Missing from the trial, however, was any consideration that endogenous CTS might influence digitalis' efficacy. Digoxin, at therapeutic concentrations, acutely inhibits NKA but, remarkably, antagonizes ouabain's action. Prolonged treatment with ouabain, but not digoxin, causes hypertension in rodents; in this model, digoxin lowers blood pressure (BP). Furthermore, NKA-bound ouabain and digoxin modulate different protein kinase signaling pathways and have disparate long-term cardiovascular effects. Reports of "brain ouabain" led to the elucidation of a new, slow neuromodulatory pathway in the brain; locally generated EO and the α2 NKA isoform help regulate sympathetic drive to the heart and vasculature. The roles of EO and α2 NKA have been studied by EO assay, ouabain-resistant mutation of α2 NKA, and immunoneutralization of EO with ouabain-binding Fab fragments. The NKA α2 CTS binding site and its endogenous ligand are required for BP elevation in many common hypertension models and full expression of cardiac remodeling and dysfunction following pressure overload or myocardial infarction. Understanding how endogenous CTS impact hypertension and HF pathophysiology and therapy should foster reconsideration of digoxin's therapeutic utility.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland.,Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Stephen S Gottlieb
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Frans H H Leenen
- Brain and Heart Research Group, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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10
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Lopina OD, Fedorov DA, Sidorenko SV, Bukach OV, Klimanova EA. Sodium Ions as Regulators of Transcription in Mammalian Cells. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:789-799. [PMID: 36171659 DOI: 10.1134/s0006297922080107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/13/2022] [Accepted: 06/13/2022] [Indexed: 06/16/2023]
Abstract
The maintenance of an uneven distribution of Na+ and K+ ions between the cytoplasm and extracellular medium is the basis for the functioning of any animal cell. Changes in the intracellular ratio of these cations occur in response to numerous stimuli and are important for the cell activity regulation. Numerous experimental data have shown that gene transcription in mammalian cells can be regulated by changes in the intracellular [Na+]i/[K+]i ratio. Here, we discuss possible mechanisms of such regulation in various cell types, with special attention to the [Ca2+]-independent signaling pathways that suggest the presence of an intracellular sensor of monovalent cations. As such sensor, we propose the secondary structures of nucleic acids called G-quadruplexes. They are widely represented in mammalian genomes and are often found in the promoters of genes encoding transcription factors.
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Affiliation(s)
- Olga D Lopina
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia.
| | - Dmitrii A Fedorov
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia
| | | | - Olesya V Bukach
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia
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11
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Shandell MA, Capatina AL, Lawrence SM, Brackenbury WJ, Lagos D. Inhibition of the Na +/K +-ATPase by cardiac glycosides suppresses expression of the IDO1 immune checkpoint in cancer cells by reducing STAT1 activation. J Biol Chem 2022; 298:101707. [PMID: 35150740 PMCID: PMC8902613 DOI: 10.1016/j.jbc.2022.101707] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 12/18/2022] Open
Abstract
Despite extensive basic and clinical research on immune checkpoint regulatory pathways, little is known about the effects of the ionic tumor microenvironment on immune checkpoint expression and function. Here we describe a mechanistic link between Na+/K+-ATPase (NKA) inhibition and activity of the immune checkpoint protein indoleamine-pyrrole 2',3'-dioxygenase 1 (IDO1). We found that IDO1 was necessary and sufficient for production of kynurenine, a downstream tryptophan metabolite, in cancer cells. We developed a spectrophotometric assay to screen a library of 31 model ion transport-targeting compounds for potential effects on IDO1 function in A549 lung and MDA-MB-231 breast cancer cells. This revealed that the cardiac glycosides ouabain and digoxin inhibited kynurenine production at concentrations that did not affect cell survival. NKA inhibition by ouabain and digoxin resulted in increased intracellular Na+ levels and downregulation of IDO1 mRNA and protein levels, which was consistent with the reduction in kynurenine levels. Knockdown of ATP1A1, the ɑ1 subunit of the NKA and target of cardiac glycosides, increased Na+ levels to a lesser extent than cardiac glycoside treatment and did not affect IDO1 expression. However, ATP1A1 knockdown significantly enhanced the effect of cardiac glycosides on IDO1 expression and kynurenine production. Mechanistically, we show that cardiac glycoside treatment resulted in curtailing the length of phosphorylation-mediated stabilization of STAT1, a transcriptional regulator of IDO1 expression, an effect enhanced by ATP1A1 knockdown. Our findings reveal cross talk between ionic modulation via cardiac glycosides and immune checkpoint protein expression in cancer cells with broad mechanistic and clinical implications.
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Affiliation(s)
- Mia A Shandell
- Department of Biology, University of York, York, United Kingdom; Hull York Medical School, University of York, York, United Kingdom; York Biomedical Research Institute, University of York, York, United Kingdom
| | - Alina L Capatina
- Department of Biology, University of York, York, United Kingdom; York Biomedical Research Institute, University of York, York, United Kingdom
| | | | - William J Brackenbury
- Department of Biology, University of York, York, United Kingdom; York Biomedical Research Institute, University of York, York, United Kingdom
| | - Dimitris Lagos
- Hull York Medical School, University of York, York, United Kingdom; York Biomedical Research Institute, University of York, York, United Kingdom.
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12
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Role of Na +/K +-ATPase in ischemic stroke: in-depth perspectives from physiology to pharmacology. J Mol Med (Berl) 2021; 100:395-410. [PMID: 34839371 DOI: 10.1007/s00109-021-02143-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 08/27/2021] [Accepted: 09/20/2021] [Indexed: 12/26/2022]
Abstract
Na+/K+-ATPase (NKA) is a large transmembrane protein expressed in all cells. It is well studied for its ion exchanging function, which is indispensable for the maintenance of electrochemical gradients across the plasma membrane and herein neuronal excitability. The widely recognized pump function of NKA closely depends on its unique structure features and conformational changes upon binding of specific ions. Various Na+-dependent secondary transport systems are rigorously controlled by the ionic gradients generated by NKA and are essential for multiple physiological processes. In addition, roles of NKA as a signal transducer have also been unveiled nowadays. Plethora of signaling cascades are defined including Src-Ras-MAPK signaling, IP3R-mediated calcium oscillation, inflammation, and autophagy though most underlying mechanisms remain elusive. Ischemic stroke occurs when the blood flow carrying nutrients and oxygen into the brain is disrupted by blood clots, which is manifested by excitotoxicity, oxidative stress, inflammation, etc. The protective effect of NKA against ischemic stress is emerging gradually with the application of specific NKA inhibitor. However, NKA-related research is limited due to the opposite effects caused by NKA inhibitor at lower doses. The present review focuses on the recent progression involving different aspects about NKA in cellular homeostasis to present an in-depth understanding of this unique protein. Moreover, essential roles of NKA in ischemic pathology are discussed to provide a platform and bright future for the improvement in clinical research on ischemic stroke.
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13
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Marck PV, Pessoa MT, Xu Y, Kutz LC, Collins DM, Yan Y, King C, Wang X, Duan Q, Cai L, Xie JX, Lingrel JB, Xie Z, Tian J, Pierre SV. Cardiac Oxidative Signaling and Physiological Hypertrophy in the Na/K-ATPase α1 s/sα2 s/s Mouse Model of High Affinity for Cardiotonic Steroids. Int J Mol Sci 2021; 22:ijms22073462. [PMID: 33801629 PMCID: PMC8036649 DOI: 10.3390/ijms22073462] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/18/2021] [Accepted: 03/23/2021] [Indexed: 11/25/2022] Open
Abstract
The Na/K-ATPase is the specific receptor for cardiotonic steroids (CTS) such as ouabain and digoxin. At pharmacological concentrations used in the treatment of cardiac conditions, CTS inhibit the ion-pumping function of Na/K-ATPase. At much lower concentrations, in the range of those reported for endogenous CTS in the blood, they stimulate hypertrophic growth of cultured cardiac myocytes through initiation of a Na/K-ATPase-mediated and reactive oxygen species (ROS)-dependent signaling. To examine a possible effect of endogenous concentrations of CTS on cardiac structure and function in vivo, we compared mice expressing the naturally resistant Na/K-ATPase α1 and age-matched mice genetically engineered to express a mutated Na/K-ATPase α1 with high affinity for CTS. In this model, total cardiac Na/K-ATPase activity, α1, α2, and β1 protein content remained unchanged, and the cardiac Na/K-ATPase dose–response curve to ouabain shifted to the left as expected. In males aged 3–6 months, increased α1 sensitivity to CTS resulted in a significant increase in cardiac carbonylated protein content, suggesting that ROS production was elevated. A moderate but significant increase of about 15% of the heart-weight-to-tibia-length ratio accompanied by an increase in the myocyte cross-sectional area was detected. Echocardiographic analyses did not reveal any change in cardiac function, and there was no fibrosis or re-expression of the fetal gene program. RNA sequencing analysis indicated that pathways related to energy metabolism were upregulated, while those related to extracellular matrix organization were downregulated. Consistent with a functional role of the latter, an angiotensin-II challenge that triggered fibrosis in the α1r/rα2s/s mouse failed to do so in the α1s/sα2s/s. Taken together, these results are indicative of a link between circulating CTS, Na/K-ATPase α1, ROS, and physiological cardiac hypertrophy in mice under baseline laboratory conditions.
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Affiliation(s)
- Pauline V. Marck
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Marco T. Pessoa
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Yunhui Xu
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Laura C. Kutz
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Dominic M. Collins
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Yanling Yan
- Department of Biomedical Sciences, Marshall University Joan C. Edwards School of Medicine, Huntington, WV 25755, USA;
| | - Cierra King
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Xiaoliang Wang
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Qiming Duan
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA;
| | - Liquan Cai
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Jeffrey X. Xie
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Jerry B. Lingrel
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA;
| | - Zijian Xie
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Jiang Tian
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
| | - Sandrine V. Pierre
- Marshall Institute for Interdisciplinary Research, Huntington, WV 25703, USA; (P.V.M.); (M.T.P.); (Y.X.); (L.C.K.); (D.M.C.); (C.K.); (X.W.); (L.C.); (Z.X.); (J.T.)
- Correspondence: ; Tel.: +1-(304)-696-3505
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14
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Silva CID, Gonçalves-de-Albuquerque CF, Moraes BPTD, Garcia DG, Burth P. Na/K-ATPase: Their role in cell adhesion and migration in cancer. Biochimie 2021; 185:1-8. [PMID: 33713729 DOI: 10.1016/j.biochi.2021.03.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 03/03/2021] [Accepted: 03/04/2021] [Indexed: 12/18/2022]
Abstract
Na/K-ATPase (NKA) is a p-type transmembrane enzyme formed by three different subunits (α, β, and γ gamma). Primarily responsible for transporting sodium and potassium through the cell membrane, it also plays a critical role in intracellular signaling. The activation of diverse intracellular pathways may trigger cell death, survival, or even cell proliferation. Changes in the NKA functions or expression in isoforms subunits impact pathological conditions, such as cancer. The NKA function affects cell adhesion, motility, and migration, which are different in the physiological and pathological states. All enzyme subunits take part in the cell adhesion process, with the β subunit being the most studied. Thus, herein we aim to highlight NKA' central role in cell adhesion, motility, and migration in cancer cells.
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Affiliation(s)
- Camila Ignácio da Silva
- Laboratório de Enzimologia e Sinalização Celular, Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil; Pós-Graduação em Ciências e Biotecnologia Universidade Federal Fluminense, Niterói, Brazil
| | - Cassiano Felippe Gonçalves-de-Albuquerque
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil; Laboratorio de Imunofarmacologia, Departamento de Bioquímica, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Bianca Portugal Tavares de Moraes
- Laboratorio de Imunofarmacologia, Departamento de Bioquímica, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Diogo Gomes Garcia
- Laboratório de Neurociências Translacional, Programa de Pós-Graduação em Neurologia, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Patrícia Burth
- Laboratório de Enzimologia e Sinalização Celular, Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil; Pós-Graduação em Ciências e Biotecnologia Universidade Federal Fluminense, Niterói, Brazil.
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15
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Lopachev AV, Lagarkova MA, Lebedeva OS, Ezhova MA, Kazanskaya RB, Timoshina YA, Khutorova AV, Akkuratov EE, Fedorova TN, Gainetdinov RR. Ouabain-Induced Gene Expression Changes in Human iPSC-Derived Neuron Culture Expressing Dopamine and cAMP-Regulated Phosphoprotein 32 and GABA Receptors. Brain Sci 2021; 11:brainsci11020203. [PMID: 33562186 PMCID: PMC7915459 DOI: 10.3390/brainsci11020203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/27/2021] [Accepted: 02/03/2021] [Indexed: 12/22/2022] Open
Abstract
Cardiotonic steroids (CTS) are specific inhibitors and endogenous ligands of a key enzyme in the CNS-the Na+, K+-ATPase, which maintains and creates an ion gradient on the plasma membrane of neurons. CTS cause the activation of various signaling cascades and changes in gene expression in neurons and other cell types. It is known that intracerebroventricular injection of cardiotonic steroid ouabain causes mania-like behavior in rodents, in part due to activation of dopamine-related signaling cascades in the dopamine and cAMP-regulated phosphoprotein 32 (DARPP-32) expressing medium spiny neurons in the striatum. Dopaminergic projections in the striatum innervate these GABAergic medium spiny neurons. The objective of this study was to assess changes in the expression of all genes in human iPSC-derived expressing DARPP-32 and GABA receptors neurons under the influence of ouabain. We noted a large number of statistically significant upregulated and downregulated genes after a 16-h incubation with non-toxic concentration (30 nM) of ouabain. These changes in the transcriptional activity were accomplished with activation of MAP-kinase ERK1/2 and transcriptional factor cAMP response element-binding protein (CREB). Thus, it can be concluded that 30 nM ouabain incubated for 16 h with human iPSC-derived expressing DARPP-32 and GABA receptors neurons activates genes associated with neuronal maturation and synapse formation, by increasing the expression of genes associated with translation, vesicular transport, and increased electron transport chain function. At the same time, the expression of genes associated with proliferation, migration, and early development of neurons decreases. These data indicate that non-toxic concentrations of ouabain may induce neuronal maturation, neurite growth, and increased synaptogenesis in dopamine-receptive GABAergic neurons, suggesting formation of plasticity and the establishment of new neuronal junctions.
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Affiliation(s)
- Alexander V. Lopachev
- Laboratory of Clinical and Experimental Neurochemistry, Research Center of Neurology, 125367 Moscow, Russia; (Y.A.T.); (A.V.K.); (T.N.F.)
- Correspondence:
| | - Maria A. Lagarkova
- Laboratory of Cell Biology, Federal Research and Clinical Center of Physical-Chemical Medicine Federal Medical Biological Agency, 119435 Moscow, Russia; (M.A.L.); (O.S.L.)
| | - Olga S. Lebedeva
- Laboratory of Cell Biology, Federal Research and Clinical Center of Physical-Chemical Medicine Federal Medical Biological Agency, 119435 Moscow, Russia; (M.A.L.); (O.S.L.)
| | - Margarita A. Ezhova
- Laboratory of Plant Genomics, Institute for Information Transmission Problems of the Russian Academy of Sciences, 127051 Moscow, Russia;
- Center of Life Sciences, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
| | - Rogneda B. Kazanskaya
- Biological Department, Saint Petersburg State University, 199034 St. Petersburg, Russia;
| | - Yulia A. Timoshina
- Laboratory of Clinical and Experimental Neurochemistry, Research Center of Neurology, 125367 Moscow, Russia; (Y.A.T.); (A.V.K.); (T.N.F.)
- Biological Department, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Anastasiya V. Khutorova
- Laboratory of Clinical and Experimental Neurochemistry, Research Center of Neurology, 125367 Moscow, Russia; (Y.A.T.); (A.V.K.); (T.N.F.)
- Biological Department, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Evgeny E. Akkuratov
- Department of Applied Physics, Royal Institute of Technology, Science for Life Laboratory, 171 65 Stockholm, Sweden;
| | - Tatiana N. Fedorova
- Laboratory of Clinical and Experimental Neurochemistry, Research Center of Neurology, 125367 Moscow, Russia; (Y.A.T.); (A.V.K.); (T.N.F.)
| | - Raul R. Gainetdinov
- Institute of Translational Biomedicine and Saint Petersburg University Hospital, Saint Petersburg State University, 199034 St. Petersburg, Russia;
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16
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Shang XF, Miao XL, Dai LX, Guo X, Li B, Pan H, Zhang JY. The acaricidal mechanism and active compounds against Psoroptes cuniculi of the methanol extract of Adonis coerulea Maxim II: Integrated proteomics and SPR analysis. Vet Parasitol 2020; 287:109267. [PMID: 33091629 DOI: 10.1016/j.vetpar.2020.109267] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 01/11/2023]
Abstract
Adonis coerulea Maxim. as a folk medicine, presented acaricidal acitvity. However, the mode of action and active compounds were unclear. In this study, using proteomics and surface plasmon resonance (SPR) technology the mode of action and active compounds of A. coerulea were investigated, as well as a sensitive and environmentally friendly analytical method developed. Proteomics analysis results showed that after treatment of mites with A. coerulea methanol extract (MEAC), 135 proteins were differentially expressed, most of them enriched in the myocardium pathway and participated in the function of the inflated cystic organ. Na+-K+-ATPase may be a potential target. Then, it was used as a target to capture the compounds from the extract using a SPR test. Twelve compounds were found, five compounds, namely ellagic acid, ouabain, convallatoxin, strophanthidin and cymarin presented the higher affinity with Na+-K+-ATPase in molecular docking test. Further study showed that the latter four compounds presented the stronger cytotoxicity and the inhibitory effect on Na+-K+-ATPase with IC50 values ranging with 2.38-0.56 μg/mL, and also showed toxicity against Psoroptes cuniculi. These results indicated that MEAC presented toxicity against mites by inhibiting Na+-K+-ATPase, and cardiac glycosides may be active compounds of this plant in terms of its acaricidal activity. Only 10 g of plant was used to investigate its active compounds. This study lays the foundation for developing sensitive methods for active compound detection.
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Affiliation(s)
- Xiao-Fei Shang
- Key Laboratory of Veterinary Pharmaceutical Development of Ministry of Agriculture, Key Laboratory of New Animal Drug Project, Gansu Province, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou 730050, PR China.
| | - Xiao-Lou Miao
- Key Laboratory of Veterinary Pharmaceutical Development of Ministry of Agriculture, Key Laboratory of New Animal Drug Project, Gansu Province, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou 730050, PR China
| | - Li-Xia Dai
- Key Laboratory of Veterinary Pharmaceutical Development of Ministry of Agriculture, Key Laboratory of New Animal Drug Project, Gansu Province, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou 730050, PR China
| | - Xiao Guo
- Tibetan Medicine Research Center of Qinghai University, Qinghai University Tibetan Medical College, Qinghai University, Xining 810016, PR China
| | - Bing Li
- Key Laboratory of Veterinary Pharmaceutical Development of Ministry of Agriculture, Key Laboratory of New Animal Drug Project, Gansu Province, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou 730050, PR China
| | - Hu Pan
- Key Laboratory of Veterinary Pharmaceutical Development of Ministry of Agriculture, Key Laboratory of New Animal Drug Project, Gansu Province, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou 730050, PR China
| | - Ji-Yu Zhang
- Key Laboratory of Veterinary Pharmaceutical Development of Ministry of Agriculture, Key Laboratory of New Animal Drug Project, Gansu Province, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou 730050, PR China.
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17
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Pessôa MTC, Valadares JMM, Rocha SC, Silva SC, McDermott JP, Sánchez G, Varotti FP, Scavone C, Ribeiro RIMA, Villar JAFP, Blanco G, Barbosa LA. 21-Benzylidene digoxin decreases proliferation by inhibiting the EGFR/ERK signaling pathway and induces apoptosis in HeLa cells. Steroids 2020; 155:108551. [PMID: 31812624 PMCID: PMC7028499 DOI: 10.1016/j.steroids.2019.108551] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/30/2019] [Accepted: 12/02/2019] [Indexed: 12/12/2022]
Abstract
Cardiotonic steroids (CTS) are agents traditionally known for their capacity to bind to the Na,K-ATPase (NKA), affecting the ion transport and the contraction of the heart. Natural CTS have been shown to also have effects on cell signaling pathways. With the goal of developing a new CTS derivative, we synthesized a new digoxin derivative, 21-benzylidene digoxin (21-BD). Previously, we have shown that this compound binds to NKA and has cytotoxic actions on cancer, but not on normal cells. Here, we further studied the mechanisms of actions of 21-BD. Working with HeLa cells, we found that 21-BD decreases the basal, as well as the insulin stimulated proliferation. 21-BD reduces phosphorylation of the epidermal growth factor receptor (EGFR) and extracellular-regulated kinase (ERK), which are involved in pathways that stimulate cell proliferation. In addition, 21-BD promotes apoptosis, which is mediated by the translocation of Bax from the cytosol to mitochondria and the release of mitochondrial cytochrome c to the cytosol. 21-BD also activated caspases-8, -9 and -3, and induced the cleavage of poly (ADP-ribose) polymerase-1 (PARP-1). Altogether, these results show that the new compound that we have synthesized exerts cytotoxic actions on HeLa cells by inhibition of cell proliferation and the activation of both the extrinsic and intrinsic apoptotic pathways. These results support the relevance of the cardiotonic steroid scaffold as modulators of cell signaling pathways and potential agents for their use in cancer.
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Affiliation(s)
- Marco Túlio C Pessôa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Jéssica M M Valadares
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Sayonarah C Rocha
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Simone C Silva
- Laboratório de Síntese Orgânica e Nanoestruturas, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Jeff P McDermott
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center (KUMC), Kansas City, KS, USA
| | - Gladis Sánchez
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center (KUMC), Kansas City, KS, USA
| | - Fernando P Varotti
- Núcleo de Pesquisa em Química Biológica (NQBio), Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Cristóforo Scavone
- Laboratório de Neurofarmacologia Molecular, Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | - Rosy I M A Ribeiro
- Laboratório de Patologia Experimental, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - José A F P Villar
- Laboratório de Síntese Orgânica e Nanoestruturas, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Gustavo Blanco
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center (KUMC), Kansas City, KS, USA
| | - Leandro A Barbosa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil.
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18
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Multipurpose Na + ions mediate excitation and cellular homeostasis: Evolution of the concept of Na + pumps and Na +/Ca 2+ exchangers. Cell Calcium 2020; 87:102166. [PMID: 32006802 DOI: 10.1016/j.ceca.2020.102166] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/14/2022]
Abstract
Ionic signalling is the most ancient form of regulation of cellular functions in response to environmental challenges. Signals, mediated by Na+ fluxes and spatio-temporal fluctuations of Na+ concentration in cellular organelles and cellular compartments contribute to the most fundamental cellular processes such as membrane excitability and energy production. At the very core of ionic signalling lies the Na+-K+ ATP-driven pump (or NKA) which creates trans-plasmalemmal ion gradients that sustain ionic fluxes through ion channels and numerous Na+-dependent transporters that maintain cellular and tissue homeostasis. Here we present a brief account of the history of research into NKA, Na+ -dependent transporters and Na+ signalling.
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19
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Orlov SN, Tverskoi AM, Sidorenko SV, Smolyaninova LV, Lopina OD, Dulin NO, Klimanova EA. Na,K-ATPase as a target for endogenous cardiotonic steroids: What's the evidence? Genes Dis 2020; 8:259-271. [PMID: 33997173 PMCID: PMC8093582 DOI: 10.1016/j.gendis.2020.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/24/2019] [Accepted: 01/09/2020] [Indexed: 12/17/2022] Open
Abstract
With an exception of few reports, the plasma concentration of ouabain and marinobufagenin, mostly studied cardiotonic steroids (CTS) assessed by immunoassay techniques, is less than 1 nM. During the last 3 decades, the implication of these endogenous CTS in the pathogenesis of hypertension and other volume-expanded disorders is widely disputed. The threshold for inhibition by CTS of human and rodent α1-Na,K-ATPase is ∼1 and 1000 nM, respectively, that rules out the functioning of endogenous CTS (ECTS) as natriuretic hormones and regulators of cell adhesion, cell-to-cell communication, gene transcription and translation, which are mediated by dissipation of the transmembrane gradients of monovalent cations. In several types of cells ouabain and marinobufagenin at concentrations corresponding to its plasma level activate Na,K-ATPase, decrease the [Na+]i/[K+]i-ratio and increase cell proliferation. Possible physiological significance and mechanism of non-canonical Na+i/K+i-dependent and Na+i/K+i-independent cell responses to CTS are discussed.
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Affiliation(s)
- Sergei N Orlov
- MV Lomonosov Moscow State University, Moscow, 119234, Russia.,National Research Tomsk State University, Tomsk, 634050, Russia.,Siberian State Medical University, Tomsk, 634050, Russia
| | | | - Svetlana V Sidorenko
- MV Lomonosov Moscow State University, Moscow, 119234, Russia.,National Research Tomsk State University, Tomsk, 634050, Russia
| | - Larisa V Smolyaninova
- MV Lomonosov Moscow State University, Moscow, 119234, Russia.,National Research Tomsk State University, Tomsk, 634050, Russia
| | - Olga D Lopina
- MV Lomonosov Moscow State University, Moscow, 119234, Russia
| | | | - Elizaveta A Klimanova
- MV Lomonosov Moscow State University, Moscow, 119234, Russia.,National Research Tomsk State University, Tomsk, 634050, Russia
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20
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Blaustein MP, Hamlyn JM. Ouabain, endogenous ouabain and ouabain-like factors: The Na + pump/ouabain receptor, its linkage to NCX, and its myriad functions. Cell Calcium 2020; 86:102159. [PMID: 31986323 DOI: 10.1016/j.ceca.2020.102159] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/01/2020] [Accepted: 01/03/2020] [Indexed: 12/12/2022]
Abstract
In this brief review we discuss some aspects of the Na+ pump and its roles in mediating the effects of ouabain and endogenous ouabain (EO): i) in regulating the cytosolic Ca2+ concentration ([Ca2+]CYT) via Na/Ca exchange (NCX), and ii) in activating a number of protein kinase (PK) signaling cascades that control a myriad of cell functions. Importantly, [Ca2+]CYT and the other signaling pathways intersect at numerous points because of the influence of Ca2+ and calmodulin in modulating some steps in those other pathways. While both mechanisms operate in virtually all cells and tissues, this article focuses primarily on their functions in the cardiovascular system, the central nervous system (CNS) and the kidneys.
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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.
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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21
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Pavlovic D. Endogenous cardiotonic steroids and cardiovascular disease, where to next? Cell Calcium 2019; 86:102156. [PMID: 31896530 PMCID: PMC7031694 DOI: 10.1016/j.ceca.2019.102156] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/24/2019] [Accepted: 12/24/2019] [Indexed: 11/18/2022]
Abstract
Ever since British Physician William Withering first described the use of foxglove extract for treatment of patients with congestive heart failure in 1785, cardiotonic steroids have been used clinically to treat heart failure and more recently atrial fibrillation. Due to their ability to bind and inhibit the ubiquitous transport enzyme sodium potassium pump, thus regulating intracellular Na+ concentration in every living cell, they are also an essential tool for research into the sodium potassium pump structure and function. Exogenous CTS have been clearly demonstrated to affect cardiovascular system through modulation of vagal tone, cardiac contraction (via ionic changes) and altered natriuresis. Reports of a number of endogenous CTS, since the 1980s, have intensified research into their physiologic and pathophysiologic roles and opened up novel therapeutic targets. Substantive evidence pointing to the role of endogenous ouabain and marinobufagenin, the two most prominent CTS, in development of cardiovascular disease has accumulated. Nevertheless, their presence, structure, biosynthesis pathways and even mechanism of action remain unclear or controversial. In this review the current state-of-the-art, the controversies and the remaining questions surrounding the role of endogenous cardiotonic steroids in health and disease are discussed.
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Affiliation(s)
- Davor Pavlovic
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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22
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Askari A. The other functions of the sodium pump. Cell Calcium 2019; 84:102105. [DOI: 10.1016/j.ceca.2019.102105] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/21/2019] [Accepted: 10/28/2019] [Indexed: 01/14/2023]
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23
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Askari A. The sodium pump and digitalis drugs: Dogmas and fallacies. Pharmacol Res Perspect 2019; 7:e00505. [PMID: 31360524 PMCID: PMC6639696 DOI: 10.1002/prp2.505] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/20/2019] [Accepted: 05/24/2019] [Indexed: 11/29/2022] Open
Abstract
The sodium pump (Na/K-ATPase) is a plasma membrane enzyme that transports Na+ and K+ against their physiological gradients in most eukaryotic cells. Besides pumping ions, the enzyme may also interact with neighboring proteins to activate cell signaling pathways that regulate cell growth. Digitalis drugs, useful for the treatment of heart failure and atrial arrhythmias, inhibit the pumping function of Na/K-ATPase and stimulate its signaling function. In the current field of research on the sodium pump and digitalis drugs, some issues that are commonly accepted to be well established are not so, and this may impede progress. Here, several such issues are identified, their histories are discussed, and their open discussions are urged. The covered unsettled questions consist of (a) the suggested hormonal role of endogenous digitalis compounds; (b) the specificity of Na/K-ATPase as the receptor for digitalis compounds; (c) the relevance of the positive inotropic action of digitalis to its use for the treatment of heart failure; (d) the conflicting findings on digitalis-induced signaling function of Na/K-ATPase; and (e) the uncertainties about the structure of Na/K-ATPase in the native cell membrane.
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Affiliation(s)
- Amir Askari
- Department of Cancer Biology, College of Medicine and Life SciencesUniversity of ToledoToledoOhio
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24
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Panizza E, Zhang L, Fontana JM, Hamada K, Svensson D, Akkuratov EE, Scott L, Mikoshiba K, Brismar H, Lehtiö J, Aperia A. Ouabain-regulated phosphoproteome reveals molecular mechanisms for Na +, K +-ATPase control of cell adhesion, proliferation, and survival. FASEB J 2019; 33:10193-10206. [PMID: 31199885 PMCID: PMC6704450 DOI: 10.1096/fj.201900445r] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ion pump Na+, K+-ATPase (NKA) is a receptor for the cardiotonic steroid ouabain. Subsaturating concentration of ouabain triggers intracellular calcium oscillations, stimulates cell proliferation and adhesion, and protects from apoptosis. However, it is controversial whether ouabain-bound NKA is considered a signal transducer. To address this question, we performed a global analysis of protein phosphorylation in COS-7 cells, identifying 2580 regulated phosphorylation events on 1242 proteins upon 10- and 20-min treatment with ouabain. Regulated phosphorylated proteins include the inositol triphosphate receptor and stromal interaction molecule, which are essential for initiating calcium oscillations. Hierarchical clustering revealed that ouabain triggers a structured phosphorylation response that occurs in a well-defined, time-dependent manner and affects specific cellular processes, including cell proliferation and cell-cell junctions. We additionally identify regulation of the phosphorylation of several calcium and calmodulin-dependent protein kinases (CAMKs), including 2 sites of CAMK type II-γ (CAMK2G), a protein known to regulate apoptosis. To verify the significance of this result, CAMK2G was knocked down in primary kidney cells. CAMK2G knockdown impaired ouabain-dependent protection from apoptosis upon treatment with high glucose or serum deprivation. In conclusion, we establish NKA as the coordinator of a broad, tightly regulated phosphorylation response in cells and define CAMK2G as a downstream effector of NKA.-Panizza, E., Zhang, L., Fontana, J. M., Hamada, K., Svensson, D., Akkuratov, E. E., Scott, L., Mikoshiba, K., Brismar, H., Lehtiö, J., Aperia, A. Ouabain-regulated phosphoproteome reveals molecular mechanisms for Na+, K+-ATPase control of cell adhesion, proliferation, and survival.
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Affiliation(s)
- Elena Panizza
- Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet, Solna, Sweden
| | - Liang Zhang
- Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Jacopo Maria Fontana
- Department of Applied Physics, Science for Life Laboratory, Royal Institute of Technology, Stockholm, Sweden
| | - Kozo Hamada
- Laboratory for Developmental Neurobiology, Brain Science Institute, Riken, Saitama, Japan
| | - Daniel Svensson
- Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Evgeny E Akkuratov
- Department of Applied Physics, Science for Life Laboratory, Royal Institute of Technology, Stockholm, Sweden
| | - Lena Scott
- Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, Brain Science Institute, Riken, Saitama, Japan
| | - Hjalmar Brismar
- Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden.,Department of Applied Physics, Science for Life Laboratory, Royal Institute of Technology, Stockholm, Sweden
| | - Janne Lehtiö
- Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet, Solna, Sweden
| | - Anita Aperia
- Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
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25
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Abstract
The Na,K-ATPase is an enzyme essential for ion homeostasis in all cells. Over the last decades, it has been well-established that in addition to the transport of Na+/K+ over the cell membrane, the Na,K-ATPase acts as a receptor transducing humoral signals intracellularly. It has been suggested that ouabain-like compounds serve as endogenous modulators of this Na,K-ATPase signal transduction. The molecular mechanisms underlying Na,K-ATPase signaling are complicated and suggest the confluence of divergent biological pathways. This review discusses recent updates on the Na,K-ATPase signaling pathways characterized or suggested in vascular smooth muscle cells. The conventional view on this signaling is based on a microdomain structure where the Na,K-ATPase controls the Na,Ca-exchanger activity via modulation of intracellular Na+ in the spatially restricted submembrane space. This, in turn, affects intracellular Ca2+ and Ca2+ load in the sarcoplasmic reticulum leading to modulation of contractility as well as gene expression. An ion-transport-independent signal transduction from the Na,K-ATPase is based on molecular interactions. This was primarily characterized in other cell types but recently also demonstrated in vascular smooth muscles. The downstream signaling from the Na,K-ATPase includes Src and phosphatidylinositol-4,5-bisphosphate 3 kinase signaling pathways and generation of reactive oxygen species. Moreover, in vascular smooth muscle cells the interaction between the Na,K-ATPase and proteins responsible for Ca2+ homeostasis, e.g., phospholipase C and inositol triphosphate receptors, contributes to an integration of the signaling pathways. Recent update on the Na,K-ATPase dependent intracellular signaling and the significance for physiological functions and pathophysiological changes are discussed in this review.
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26
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In Vitro Cytotoxicity Induced by the Bufadienolides 1α,2α-Epoxyscillirosidine and Lanceotoxin B on Rat Myocardial and Mouse Neuroblastoma Cell Lines. Toxins (Basel) 2019; 11:toxins11010014. [PMID: 30609690 PMCID: PMC6356634 DOI: 10.3390/toxins11010014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/21/2018] [Accepted: 12/23/2018] [Indexed: 11/22/2022] Open
Abstract
Consumption of bufadienolide-containing plants are responsible for many livestock mortalities annually. Bufadienolides are divided into two groups; non-cumulative bufadienolides and cumulative bufadienolides. Cumulative bufadienolides are referred to as neurotoxic, as the chronic intoxication with this type of bufadienolide results in a paretic/paralytic syndrome known as ‘krimpsiekte’. The in vitro cytotoxicity of a non-cumulative bufadienolide, 1α,2α-epoxyscillirosidine, and a cumulative bufadienolide, lanceotoxin B, were compared using the MTT ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction) assay after exposing rat myocardial (H9c2) and mouse neuroblastoma (Neuro-2a) cell lines. The effect of these two bufadienolides on cell ultrastructure was also investigated using transmission electron microscopy (TEM). H9c2 cells exhibited greater cytotoxicity when exposed to 1α,2α-epoxyscillirosidine, compared to lanceotoxin B. In contrast, Neuro-2a cells were more susceptible to lanceotoxin B. The EC50 (half maximal effective concentration) of lanceotoxin B exposure of Neuro-2a cells for 24–72 h ranged from 4.4–5.5 µM compared to EC50s of 35.7–37.6 µM for 1α,2α-epoxyscillirosidine exposure of Neuro-2a cells over the same period. 1α,2α-Epoxyscillirosidine induced extensive vacuolization in both cell types, with swollen RER (rough endoplasmic reticulum) and perinuclear spaces. Lanceotoxin B caused swelling of the mitochondria and sequestration of cytoplasmic material within autophagic vesicles. These results corroborate the notion that cumulative bufadienolides are neurotoxic.
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27
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Amarelle L, Lecuona E. A Nonhospitable Host: Targeting Cellular Factors as an Antiviral Strategy for Respiratory Viruses. Am J Respir Cell Mol Biol 2018; 59:666-667. [PMID: 30230347 PMCID: PMC6293076 DOI: 10.1165/rcmb.2018-0268ed] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Luciano Amarelle
- 1 Facultad de Medicina Universidad de la República Montevideo, Uruguay and
| | - Emilia Lecuona
- 2 Feinberg School of Medicine Northwestern University Chicago, Illinois
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28
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Nakashima A, Kawamoto T, Noshiro M, Ueno T, Doi S, Honda K, Maruhashi T, Noma K, Honma S, Masaki T, Higashi Y, Kato Y. Dec1 and CLOCK Regulate Na +/K +-ATPase β1 Subunit Expression and Blood Pressure. Hypertension 2018; 72:746-754. [PMID: 30012868 DOI: 10.1161/hypertensionaha.118.11075] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Blood pressure shows a circadian rhythm, and recent studies have suggested the involvement of a molecular clock system in its control. In the clock system, the CLOCK (circadian locomotor output cycles kaput):BMAL1 (brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein-1) heterodimer enhances promoter activity of clock genes, and DEC1 (BHLHE40/STRA13/SHARP-2) represses CLOCK/BMAL1-enhanced promoter activity through competition for binding to the clock element, CACGTG E-box. However, the molecular mechanisms by which this system regulates blood pressure remain unclear. Here, we show that DEC1 suppressed the expression of ATP1B1, which encodes the β1 subunit of the Na+/K+-ATPase and elevated blood pressure. Using chromatin immunoprecipitation and chromatin immunoprecipitation-on-chip analyses, we found that DEC1 and CLOCK bound to E-boxes in the ATP1B1 promoter. Luciferase assays revealed that CLOCK:BMAL1 heterodimer enhanced transcription from the ATP1B1 promoter, whereas DEC1 suppressed this transactivation. Accordingly, Atp1b1 mRNA and protein levels in mouse kidney, aorta, and heart showed a circadian rhythm that was antiphasic to the blood pressure rhythm. Furthermore, Dec1-deficient mice showed enhanced Atp1b1 expression in these tissues and reduced blood pressure. In contrast, Clock-mutant mice showed reduced Atp1b1 expression and elevated blood pressure. Our results raise the possibility that transcriptional regulation of Atp1b1 by DEC1 and CLOCK:BMAL1 contributes to blood pressure.
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Affiliation(s)
- Ayumu Nakashima
- From the Department of Cardiovascular Regeneration and Medicine, Research Institute for Radiation Biology and Medicine (A.N., K.N., Y.H.)
- Department of Stem Cell Biology and Medicine (A.N.)
- Department of Nephrology (A.N., T.U., S.D., T. Masaki)
| | - Takeshi Kawamoto
- Department of Dental and Medical Biochemistry (T.K., M.N., K.H., Y.K.)
| | - Mitsuhide Noshiro
- Department of Dental and Medical Biochemistry (T.K., M.N., K.H., Y.K.)
| | | | - Shigehiro Doi
- Department of Nephrology (A.N., T.U., S.D., T. Masaki)
| | - Kiyomasa Honda
- Department of Dental and Medical Biochemistry (T.K., M.N., K.H., Y.K.)
| | - Tatsuya Maruhashi
- Department of Cardiovascular Medicine (T. Maruhashi), Graduate School of Biomedical & Health Sciences, Hiroshima University, Japan
| | - Kensuke Noma
- From the Department of Cardiovascular Regeneration and Medicine, Research Institute for Radiation Biology and Medicine (A.N., K.N., Y.H.)
- Division of Regeneration and Medicine, Medical Center for Translational and Clinical Research (K.N., Y.H.), Hiroshima University Hospital, Japan
| | - Sato Honma
- Department of Chronomedicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan (S.H.)
| | - Takao Masaki
- Department of Nephrology (A.N., T.U., S.D., T. Masaki)
| | - Yukihito Higashi
- From the Department of Cardiovascular Regeneration and Medicine, Research Institute for Radiation Biology and Medicine (A.N., K.N., Y.H.)
- Division of Regeneration and Medicine, Medical Center for Translational and Clinical Research (K.N., Y.H.), Hiroshima University Hospital, Japan
| | - Yukio Kato
- Department of Dental and Medical Biochemistry (T.K., M.N., K.H., Y.K.)
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29
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The Na/K-ATPase Signaling: From Specific Ligands to General Reactive Oxygen Species. Int J Mol Sci 2018; 19:ijms19092600. [PMID: 30200500 PMCID: PMC6163532 DOI: 10.3390/ijms19092600] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/10/2018] [Accepted: 08/28/2018] [Indexed: 12/16/2022] Open
Abstract
The signaling function of the Na/K-ATPase has been established for 20 years and is widely accepted in the field, with many excellent reports and reviews not cited here. Even though there is debate about the underlying mechanism, the signaling function is unquestioned. This short review looks back at the evolution of Na/K-ATPase signaling, from stimulation by cardiotonic steroids (also known as digitalis-like substances) as specific ligands to stimulation by reactive oxygen species (ROS) in general. The interplay of cardiotonic steroids and ROS in Na/K-ATPase signaling forms a positive-feedback oxidant amplification loop that has been implicated in some pathophysiological conditions.
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30
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Lin S, Liu K, Zhang Y, Jiang M, Lu R, Folts CJ, Gao X, Noble MD, Zhao T, Zhou Z, Lan X, Que J. Pharmacological targeting of p38 MAP-Kinase 6 (MAP2K6) inhibits the growth of esophageal adenocarcinoma. Cell Signal 2018; 51:222-232. [PMID: 30102978 DOI: 10.1016/j.cellsig.2018.08.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 07/20/2018] [Accepted: 08/09/2018] [Indexed: 12/12/2022]
Abstract
Drug repurposing with a better understanding of the underlying mechanism has provided new avenues to find treatment for malignancies. Esophageal adenocarcinoma (EAC) is a rapidly increasing cancer with a dismal 5-year survival rate of <15%. Lack of efficient treatment options contributes to the high mortality rate of EAC. To find new therapy against EAC we performed unbiased drug screening of an FDA-approved drug library and identified that the cardiac glycosides including Ouabain, Digoxin and Digitoxin efficiently inhibit the proliferation of EAC cell lines (OE33 and OE19) both in vitro and in vivo. RNA-Sequencing analysis combined with RNAi screening revealed that Ouabain suppresses the proliferation of EAC cells through downregulation of p38 MAP-Kinase 6 (MAP2K6, also known as MKK6). Consistently, shRNA-mediated knockdown of MKK6 reduced the proliferation of EAC cells and tumor growth. Further analysis demonstrated that MKK6 inhibition leads to the reduced levels of the transcription factor SOX9. In line with this finding, deletion of SOX9 with CRISPR/Cas9 resulted in decreased proliferation of EACs in 3D organoid culture and reduced tumor growth. Together these findings establish a druggable axis that can be harnessed for therapeutic gain against EAC.
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Affiliation(s)
- Sijie Lin
- Division of Digestive and Liver Diseases and Center for Human Development, Department of Medicine, Columbia University, NY 10032, USA; Institute for Laboratory Medicine, Fuzhou General Hospital, PLA, Fuzhou, Fujian 350025, PR China
| | - Kuancan Liu
- Division of Digestive and Liver Diseases and Center for Human Development, Department of Medicine, Columbia University, NY 10032, USA; Institute for Laboratory Medicine, Fuzhou General Hospital, PLA, Fuzhou, Fujian 350025, PR China; Dong fang Hospital, Xiamen University, Fuzhou, Fujian 350025, PR China.
| | - Yongchun Zhang
- Division of Digestive and Liver Diseases and Center for Human Development, Department of Medicine, Columbia University, NY 10032, USA
| | - Ming Jiang
- Division of Digestive and Liver Diseases and Center for Human Development, Department of Medicine, Columbia University, NY 10032, USA
| | - Rong Lu
- Division of Digestive and Liver Diseases and Center for Human Development, Department of Medicine, Columbia University, NY 10032, USA
| | - Christopher J Folts
- Department of Biomedical Genetics, University of Rochester, Rochester NY14642, USA
| | - Xia Gao
- Division of Digestive and Liver Diseases and Center for Human Development, Department of Medicine, Columbia University, NY 10032, USA
| | - Mark D Noble
- Department of Biomedical Genetics, University of Rochester, Rochester NY14642, USA
| | - Tingting Zhao
- Dong fang Hospital, Xiamen University, Fuzhou, Fujian 350025, PR China
| | - Zhongren Zhou
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, MO63110, USA
| | - Xiaopeng Lan
- Institute for Laboratory Medicine, Fuzhou General Hospital, PLA, Fuzhou, Fujian 350025, PR China; Dong fang Hospital, Xiamen University, Fuzhou, Fujian 350025, PR China.
| | - Jianwen Que
- Division of Digestive and Liver Diseases and Center for Human Development, Department of Medicine, Columbia University, NY 10032, USA.
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31
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Amarelle L, Lecuona E. The Antiviral Effects of Na,K-ATPase Inhibition: A Minireview. Int J Mol Sci 2018; 19:ijms19082154. [PMID: 30042322 PMCID: PMC6121263 DOI: 10.3390/ijms19082154] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/11/2022] Open
Abstract
Since being first described more than 60 years ago, Na,K-ATPase has been extensively studied, while novel concepts about its structure, physiology, and biological roles continue to be elucidated. Cardiac glycosides not only inhibit the pump function of Na,K-ATPase but also activate intracellular signal transduction pathways, which are important in many biological processes. Recently, antiviral effects have been described as a novel feature of Na,K-ATPase inhibition with the use of cardiac glycosides. Cardiac glycosides have been reported to be effective against both DNA viruses such as cytomegalovirus and herpes simplex and RNA viruses such as influenza, chikungunya, coronavirus, and respiratory syncytial virus, among others. Consequently, cardiac glycosides have emerged as potential broad-spectrum antiviral drugs, with the great advantage of targeting cell host proteins, which help to minimize resistance to antiviral treatments, making them a very promising strategy against human viral infections. Here, we review the effect of cardiac glycosides on viral biology and the mechanisms by which these drugs impair the replication of this array of different viruses.
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Affiliation(s)
- Luciano Amarelle
- Division of Pulmonary and Critical Care, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
- Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay.
| | - Emilia Lecuona
- Division of Pulmonary and Critical Care, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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32
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Câmara DR, Kastelic JP, Thundathil JC. Role of the Na +/K +-ATPase ion pump in male reproduction and embryo development. Reprod Fertil Dev 2018; 29:1457-1467. [PMID: 27456939 DOI: 10.1071/rd16091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/19/2016] [Indexed: 12/18/2022] Open
Abstract
Na+/K+-ATPase was one of the first ion pumps studied because of its importance in maintaining osmotic and ionic balances between intracellular and extracellular environments, through the exchange of three Na+ ions out and two K+ ions into a cell. This enzyme, which comprises two main subunits (α and β), with or without an auxiliary polypeptide (γ), can have specific biochemical properties depending on the expression of associated isoforms (α1β1 and/or α2β1) in the cell. In addition to the importance of Na+/K+-ATPase in ensuring the function of many tissues (e.g. brain, heart and kidney), in the reproductive tract this protein is essential for embryo development because of its roles in blastocoel formation and embryo hatching. In the context of male reproduction, the discovery of a very specific subunit (α4), apparently restricted to male germ cells, only expressed after puberty and able to influence sperm function (e.g. motility and capacitation), opened a remarkable field for further investigations regarding sperm biology. Therefore, the present review focuses on the importance of Na+/K+-ATPase on male reproduction and embryo development.
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Affiliation(s)
- D R Câmara
- Faculdade de Medicina Veterinária, Universidade Federal de Alagoas, Fazenda São Luiz, s/n, Zona Rural do Município de Viçosa, Viçosa-AL, CEP: 57700-000, Brazil
| | - J P Kastelic
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB T2N 4N1, Canada
| | - J C Thundathil
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB T2N 4N1, Canada
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33
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Lopachev AV, Abaimov DA, Fedorova TN, Lopacheva OM, Akkuratova NV, Akkuratov EE. Cardiotonic Steroids as Potential Endogenous Regulators in the Nervous System. NEUROCHEM J+ 2018. [DOI: 10.1134/s1819712418010087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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34
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Lopachev AV, Lopacheva OM, Nikiforova KA, Filimonov IS, Fedorova TN, Akkuratov EE. Comparative Action of Cardiotonic Steroids on Intracellular Processes in Rat Cortical Neurons. BIOCHEMISTRY (MOSCOW) 2018; 83:140-151. [DOI: 10.1134/s0006297918020062] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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35
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Pessôa MTC, Alves SLG, Taranto AG, Villar JAFP, Blanco G, Barbosa LA. Selectivity analyses of γ-benzylidene digoxin derivatives to different Na,K-ATPase α isoforms: a molecular docking approach. J Enzyme Inhib Med Chem 2017; 33:85-97. [PMID: 29115894 PMCID: PMC6009882 DOI: 10.1080/14756366.2017.1380637] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Digoxin and other cardiotonic steroids (CTS) exert their effect by inhibiting Na,K-ATPase (NKA) activity. CTS bind to the various NKA isoforms that are expressed in different cell types, which gives CTS their narrow therapeutic index. We have synthesised a series of digoxin derivatives (γ-Benzylidene digoxin derivatives) with substitutions in the lactone ring (including non-oxygen and ether groups), to obtain CTS with better NKA isoform specificity. Some of these derivatives show some NKA isoform selective effects, with BD-3, BD-8, and BD-13 increasing NKA α2 activity, BD-5 inhibiting NKA α1 and NKA α3, BD-10 reducing NKA α1, but stimulating NKA α2 and α3; and BD-14, BD-15, and BD-16 enhancing NKA α3 activity. A molecular-docking approach favoured NKA isoform specific interactions for the compounds that supported their observed activity. These results show that BD compounds are a new type of CTS with the capacity to target NKA activity in an isoform-specific manner.
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Affiliation(s)
- Marco T C Pessôa
- a Laboratório de Bioquímica Celular , Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindú , Divinópolis , Brazil
| | - Silmara L G Alves
- b Laboratório de Síntese Orgânica e Nanoestruturas , Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindú , Divinópolis , Brazil
| | - Alex G Taranto
- c Laboratório de Modelagem Molecular , Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindú , Divinópolis , Brazil
| | - José A F P Villar
- b Laboratório de Síntese Orgânica e Nanoestruturas , Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindú , Divinópolis , Brazil
| | - Gustavo Blanco
- d Department of Molecular and Integrative Physiology , Kansas University Medical Center , Kansas City , KS , USA
| | - Leandro A Barbosa
- a Laboratório de Bioquímica Celular , Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindú , Divinópolis , Brazil
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36
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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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37
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Yurek DM, Fletcher-Turner A, Moore J, Chai L, Mahanthappa N. Co-Grafts of Fetal Ventral Mesencephalon and Fibroblasts Expressing Sonic Hedgehog: Effect on Survival and Function of Dopamine Grafts. Cell Transplant 2017. [DOI: 10.3727/000000001783986305] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- David M. Yurek
- Department of Surgery/Neurosurgery, University of Kentucky College of Medicine, Lexington, KY 40536-0305
| | - Anita Fletcher-Turner
- Department of Surgery/Neurosurgery, University of Kentucky College of Medicine, Lexington, KY 40536-0305
| | - Jennifer Moore
- Department of Surgery/Neurosurgery, University of Kentucky College of Medicine, Lexington, KY 40536-0305
| | - Ling Chai
- Curis, Inc., 45 Moulton Street, Cambridge, MA 02138
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Gopalakrishnan K, More AS, Hankins GD, Nanovskaya TN, Kumar S. Postnatal Cardiovascular Consequences in the Offspring of Pregnant Rats Exposed to Smoking and Smoking Cessation Pharmacotherapies. Reprod Sci 2017; 24:919-933. [PMID: 27733658 PMCID: PMC5933098 DOI: 10.1177/1933719116673199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Approximately 20% of pregnant women smoke despite intentions to quit. Smoking cessation drugs, such as nicotine replacement therapy (NRT) and bupropion, are recommended treatments. Adverse cardiovascular outcomes in offspring have raised concerns about NRT's safety during pregnancy. However, the effect of bupropion is unknown. Using a rat model, we determined whether NRT and bupropion interventions during pregnancy are safer than continued smoking on offspring's cardiovascular function. Male offspring of controls and dams exposed to cigarette smoke (1.6 packs/day, inhalation), nicotine (2 mg/kg/d subcutaneously), and bupropion (13 mg/kg twice daily orally) were assessed for fetoplacental weight, cardiac function, blood pressure, and vascular reactivity. Fetoplacental weights were decreased and spontaneous beating and intracellular calcium in neonatal cardiomyocytes were increased in smoking, nicotine, and bupropion offspring; however, these effects were more accentuated in smoking followed by nicotine and bupropion offspring. Increased heart rate and decreased cardiac output, stroke volume, and left ventricular percent posterior wall thickening were observed in smoking, nicotine, and bupropion offspring. The left ventricular mass was reduced in smoking and nicotine but not in bupropion offspring. Blood pressure was higher with decreased endothelium-dependent relaxation and exaggerated vascular contraction to angiotensin II in smoking and nicotine offspring, with more pronounced dysfunctions in smoking than nicotine offspring. Maternal bupropion did not impact offspring's blood pressure, endothelium-dependent relaxation, and vascular contraction. In conclusion, maternal nicotine intervention adversely affects offspring's cardiovascular outcomes, albeit less severely than continued smoking. However, bupropion causes cardiac derangement in offspring but does not adversely affect blood pressure and vascular function.
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Affiliation(s)
- Kathirvel Gopalakrishnan
- Department of Obstetrics & Gynecology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Amar S. More
- Department of Obstetrics & Gynecology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Gary D. Hankins
- Department of Obstetrics & Gynecology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Tatiana N. Nanovskaya
- Department of Obstetrics & Gynecology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Sathish Kumar
- Department of Obstetrics & Gynecology, The University of Texas Medical Branch, Galveston, TX, USA
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Na⁺ i,K⁺ i-Dependent and -Independent Signaling Triggered by Cardiotonic Steroids: Facts and Artifacts. Molecules 2017; 22:molecules22040635. [PMID: 28420099 PMCID: PMC6153942 DOI: 10.3390/molecules22040635] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 03/31/2017] [Accepted: 04/11/2017] [Indexed: 11/17/2022] Open
Abstract
Na⁺,K⁺-ATPase is the only known receptor of cardiotonic steroids (CTS) whose interaction with catalytic α-subunits leads to inhibition of this enzyme. As predicted, CTS affect numerous cellular functions related to the maintenance of the transmembrane gradient of monovalent cations, such as electrical membrane potential, cell volume, transepithelial movement of salt and osmotically-obliged water, symport of Na⁺ with inorganic phosphate, glucose, amino acids, nucleotides, etc. During the last two decades, it was shown that side-by-side with these canonical Na⁺i/K⁺i-dependent cellular responses, long-term exposure to CTS affects transcription, translation, tight junction, cell adhesion and exhibits tissue-specific impact on cell survival and death. It was also shown that CTS trigger diverse signaling cascades via conformational transitions of the Na⁺,K⁺-ATPase α-subunit that, in turn, results in the activation of membrane-associated non-receptor tyrosine kinase Src, phosphatidylinositol 3-kinase and the inositol 1,4,5-triphosphate receptor. These findings allowed researchers to propose that endogenous CTS might be considered as a novel class of steroid hormones. We focus our review on the analysis of the relative impact Na⁺i,K⁺i-mediated and -independent pathways in cellular responses evoked by CTS.
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40
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Hosseinzadeh Z, Singh Y, Shimshek DR, van der Putten H, Wagner CA, Lang F. Leucine-Rich Repeat Kinase 2 (Lrrk2)-Sensitive Na +/K + ATPase Activity in Dendritic Cells. Sci Rep 2017; 7:41117. [PMID: 28120865 PMCID: PMC5264149 DOI: 10.1038/srep41117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/14/2016] [Indexed: 12/18/2022] Open
Abstract
Leucine-rich repeat kinase 2 (Lrrk2) has been implicated in the pathophysiology of Parkinson's disease. Lrrk2 is expressed in diverse cells including neurons and dendritic cells (DCs). In DCs Lrrk2 was shown to up-regulate Na+/Ca2+-exchanger activity. The elimination of Ca2+ by Na+/Ca2+ -exchangers requires maintenance of the Na+ gradient by the Na+/K+ -ATPase. The present study thus explored whether Lrrk2 impacts on Na+/K+ -ATPase expression and function. To this end DCs were isolated from gene-targeted mice lacking Lrrk2 (Lrrk2-/-) and their wild-type littermates (Lrrk2+/+). Na+/K+ -ATPase activity was estimated from K+ induced, ouabain sensitive, current determined by whole cell patch clamp. Na+/K+ -ATPase α1 subunit transcript and protein levels were determined by RT-qPCR and flow cytometry. As a result, the K+ induced current was significantly smaller in Lrrk2-/- than in Lrrk2+/+ DCs and was completely abolished by ouabain (100 μM) in both genotypes. The K+ induced, ouabain sensitive, current in Lrrk2+/+ DCs was significantly blunted by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). The Na+/K+ -ATPase α1 subunit transcript and protein levels were significantly lower in Lrrk2-/- than in Lrrk2+/+ DCs and significantly decreased by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). In conclusion, Lrrk2 is a powerful regulator of Na+/K+ -ATPase expression and activity in dendritic cells.
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Affiliation(s)
- Zohreh Hosseinzadeh
- Department of Cardiology, Vascular Medicine and Physiology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany
- Experimental Retinal Prosthetics Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Yogesh Singh
- Department of Cardiology, Vascular Medicine and Physiology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany
| | - Derya R. Shimshek
- Department of Neuroscience, Novartis Institutes for BioMedical Research, CH-4002 Basel, Switzerland
| | - Herman van der Putten
- Department of Neuroscience, Novartis Institutes for BioMedical Research, CH-4002 Basel, Switzerland
- National Contest for Life (NCL) Foundation, 203555 Hamburg, Germany
| | - Carsten A. Wagner
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Florian Lang
- Department of Cardiology, Vascular Medicine and Physiology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany
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Lopachev AV, Lopacheva OM, Osipova EA, Vladychenskaya EA, Smolyaninova LV, Fedorova TN, Koroleva OV, Akkuratov EE. Ouabain-induced changes in MAP kinase phosphorylation in primary culture of rat cerebellar cells. Cell Biochem Funct 2017; 34:367-77. [PMID: 27338714 DOI: 10.1002/cbf.3199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 05/21/2016] [Accepted: 05/23/2016] [Indexed: 02/06/2023]
Abstract
Cardiotonic steroid (CTS) ouabain is a well-established inhibitor of Na,K-ATPase capable of inducing signalling processes including changes in the activity of the mitogen activated protein kinases (MAPK) in various cell types. With increasing evidence of endogenous CTS in the blood and cerebrospinal fluid, it is of particular interest to study ouabain-induced signalling in neurons, especially the activation of MAPK, because they are the key kinases activated in response to extracellular signals and regulating cell survival, proliferation and apoptosis. In this study we investigated the effect of ouabain on the level of phosphorylation of three MAPK (ERK1/2, JNK and p38) and on cell survival in the primary culture of rat cerebellar cells. Using Western blotting we described the time course and concentration dependence of phosphorylation for ERK1/2, JNK and p38 in response to ouabain. We discovered that ouabain at a concentration of 1 μM does not cause cell death in cultured neurons while it changes the phosphorylation level of the three MAPK: ERK1/2 is phosphorylated transiently, p38 shows sustained phosphorylation, and JNK is dephosphorylated after a long-term incubation. We showed that ERK1/2 phosphorylation increase does not depend on ouabain-induced calcium increase and p38 activation. Changes in p38 phosphorylation, which is independent from ERK1/2 activation, are calcium dependent. Changes in JNK phosphorylation are calcium dependent and also depend on ERK1/2 and p38 activation. Ten-micromolar ouabain leads to cell death, and we conclude that different effects of 1-μM and 10-μM ouabain depend on different ERK1/2 and p38 phosphorylation profiles. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Alexander V Lopachev
- Research Center of Neurology, Moscow, Russia.,Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Olga M Lopacheva
- Research Center of Neurology, Moscow, Russia.,Lomonosov Moscow State University, International Biotechnological Center, Moscow, Russia
| | - Ekaterina A Osipova
- Lomonosov Moscow State University, International Biotechnological Center, Moscow, Russia.,Lomonosov Moscow State University, Faculty of Chemistry, Department of Chemical Enzymology, Moscow, Russia
| | | | - Larisa V Smolyaninova
- Lomonosov Moscow State University, International Biotechnological Center, Moscow, Russia.,Lomonosov Moscow State University, Faculty of Biology, Department of Biochemistry, Moscow, Russia
| | | | - Olga V Koroleva
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Evgeny E Akkuratov
- St. Petersburg State University, Institute of Translational Biomedicine, St. Petersburg, Russia
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42
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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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43
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Akkuratov EE, Wu J, Sowa D, Shah ZA, Liu L. Ouabain-Induced Signaling and Cell Survival in SK-N-SH Neuroblastoma Cells Differentiated by Retinoic Acid. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2016; 14:1343-9. [PMID: 26295826 PMCID: PMC5388798 DOI: 10.2174/1871527314666150821103008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/18/2015] [Indexed: 11/22/2022]
Abstract
Ouabain stimulates activation of various signaling cascades such as protein kinase B (Akt) and Extracellular-signaling-regulated kinase 1/2 (ERK 1/2) in various cell lines. Retinoic acid (RA) is commonly used to induce neuroblastoma differentiation in cultures. Upon RA administration, human neuroblastoma cell line, SK-N-SH demonstrated neurite extensions, which is an indicator of neuronal cell differentiation. Here we report that ouabain-induced signaling is altered under the action of 1 μM RA in human neuroblastoma SK-N-SH cells. RA increased the expression of p110α subunit of phosphoinositide 3-kinase (PI3K), Akt and β1 subunit of Na+/K+-ATPase. Ouabain activated Akt and ERK 1/2 in differentiated SK-N-SH cells; this effect was not observed in non-differentiated SK-N-SH cells. Long-term incubation of non-differentiated SK-N-SH with 1 μM ouabain led to a decrease in the number of cells; this effect was reduced in differentiated SK-N-SH cells. Taken together, these results suggest that ouabain leads to cell death in neuroblastoma cells rather than neuronal cells due to the different response to ouabain manifested by activation of Akt and ERK 1/2.
Highlights
• RA increases the expression of p110α subunit of PI3K, Akt and β1 subunit of Na+/K+-ATPase • Ouabain induces activation of Akt and ERK 1/2 in differentiated SK-N-SH cells but not in non-differentiated cells • 1 μM ouabain leads to a decrease in the number of cells in non-differentiated SK-N-SH • Reduction of ouabain-induced cell death in differentiated SK-N-SH
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Affiliation(s)
| | | | | | | | - Lijun Liu
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH, USA.
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44
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Kinoshita PF, Leite JA, Orellana AMM, Vasconcelos AR, Quintas LEM, Kawamoto EM, Scavone C. The Influence of Na(+), K(+)-ATPase on Glutamate Signaling in Neurodegenerative Diseases and Senescence. Front Physiol 2016; 7:195. [PMID: 27313535 PMCID: PMC4890531 DOI: 10.3389/fphys.2016.00195] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/17/2016] [Indexed: 12/17/2022] Open
Abstract
Decreased Na(+), K(+)-ATPase (NKA) activity causes energy deficiency, which is commonly observed in neurodegenerative diseases. The NKA is constituted of three subunits: α, β, and γ, with four distinct isoforms of the catalytic α subunit (α1-4). Genetic mutations in the ATP1A2 gene and ATP1A3 gene, encoding the α2 and α3 subunit isoforms, respectively can cause distinct neurological disorders, concurrent to impaired NKA activity. Within the central nervous system (CNS), the α2 isoform is expressed mostly in glial cells and the α3 isoform is neuron-specific. Mutations in ATP1A2 gene can result in familial hemiplegic migraine (FHM2), while mutations in the ATP1A3 gene can cause Rapid-onset dystonia-Parkinsonism (RDP) and alternating hemiplegia of childhood (AHC), as well as the cerebellar ataxia, areflexia, pescavus, optic atrophy and sensorineural hearing loss (CAPOS) syndrome. Data indicates that the central glutamatergic system is affected by mutations in the α2 isoform, however further investigations are required to establish a connection to mutations in the α3 isoform, especially given the diagnostic confusion and overlap with glutamate transporter disease. The age-related decline in brain α2∕3 activity may arise from changes in the cyclic guanosine monophosphate (cGMP) and cGMP-dependent protein kinase (PKG) pathway. Glutamate, through nitric oxide synthase (NOS), cGMP and PKG, stimulates brain α2∕3 activity, with the glutamatergic N-methyl-D-aspartate (NMDA) receptor cascade able to drive an adaptive, neuroprotective response to inflammatory and challenging stimuli, including amyloid-β. Here we review the NKA, both as an ion pump as well as a receptor that interacts with NMDA, including the role of NKA subunits mutations. Failure of the NKA-associated adaptive response mechanisms may render neurons more susceptible to degeneration over the course of aging.
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Affiliation(s)
- Paula F. Kinoshita
- Department of Pharmacology, Institute of Biomedical Science, University of São PauloSão Paulo, Brazil
| | - Jacqueline A. Leite
- Department of Pharmacology, Institute of Biomedical Science, University of São PauloSão Paulo, Brazil
| | - Ana Maria M. Orellana
- Department of Pharmacology, Institute of Biomedical Science, University of São PauloSão Paulo, Brazil
| | - Andrea R. Vasconcelos
- Department of Pharmacology, Institute of Biomedical Science, University of São PauloSão Paulo, Brazil
| | - Luis E. M. Quintas
- Laboratory of Biochemical and Molecular Pharmacology, Institute of Biomedical Sciences, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Elisa M. Kawamoto
- Department of Pharmacology, Institute of Biomedical Science, University of São PauloSão Paulo, Brazil
| | - Cristoforo Scavone
- Department of Pharmacology, Institute of Biomedical Science, University of São PauloSão Paulo, Brazil
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45
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Aperia A, Akkuratov EE, Fontana JM, Brismar H. Na+-K+-ATPase, a new class of plasma membrane receptors. Am J Physiol Cell Physiol 2016; 310:C491-5. [PMID: 26791490 DOI: 10.1152/ajpcell.00359.2015] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Na(+)-K(+)-ATPase (NKA) differs from most other ion transporters, not only in its capacity to maintain a steep electrochemical gradient across the plasma membrane, but also as a receptor for a family of cardiotonic steroids, to which ouabain belongs. Studies from many groups, performed during the last 15 years, have demonstrated that ouabain, a member of the cardiotonic steroid family, can activate a network of signaling molecules, and that NKA will also serve as a signal transducer that can provide a feedback loop between NKA and the mitochondria. This brief review summarizes the current knowledge and controversies with regard to the understanding of NKA signaling.
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Affiliation(s)
- Anita Aperia
- Science for Life Laboratory, Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden; and
| | - Evgeny E Akkuratov
- Science for Life Laboratory, Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden; and
| | - Jacopo Maria Fontana
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
| | - Hjalmar Brismar
- Science for Life Laboratory, Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden; and Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
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46
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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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Endogenous Ouabain: An Old Cardiotonic Steroid as a New Biomarker of Heart Failure and a Predictor of Mortality after Cardiac Surgery. BIOMED RESEARCH INTERNATIONAL 2015; 2015:714793. [PMID: 26609532 PMCID: PMC4644558 DOI: 10.1155/2015/714793] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 10/05/2015] [Indexed: 12/17/2022]
Abstract
Cardiovascular diseases remain the main cause of mortality and morbidity worldwide; primary prevention is a priority for physicians. Biomarkers are useful tools able to identify high-risk individuals, guide treatments, and determine prognosis. Our aim is to investigate Endogenous Ouabain (EO), an adrenal stress hormone with hemodynamic effects, as a valuable biomarker of heart failure. In a population of 845 patients undergoing elective cardiac surgery, we have investigated the relationships between EO and echocardiography parameters/plasmatic biomarker of cardiac function. EO was found to be correlated negatively with left ventricular EF (p = 0.001), positively with Cardiac End-Diastolic Diameter (p = 0.047), and positively with plasmatic NT-proBNP level (p = 0.02). Moreover, a different plasmatic EO level (both preoperative and postoperative) was found according to NYHA class (p = 0.013). All these results have been replicated on an independent cohort of patients (147 subjects from US). Finally, a higher EO level in the immediate postoperative time was indicative of a more severe cardiological condition and it was associated with increased perioperative mortality risk (p = 0.023 for 30-day morality). Our data suggest that preoperative and postoperative plasmatic EO level identifies patients with a more severe cardiovascular presentation at baseline. These patients have a higher risk of morbidity and mortality after cardiac surgery.
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Pavlovic D. The role of cardiotonic steroids in the pathogenesis of cardiomyopathy in chronic kidney disease. Nephron Clin Pract 2014; 128:11-21. [PMID: 25341357 DOI: 10.1159/000363301] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cardiotonic steroids (CTS) are a new class of hormones that circulate in the blood and are divided into two distinct groups, cardenolides, such as ouabain and digoxin, and bufadienolides, such as marinobufagenin, telocinobufagin and bufalin. They have the ability to bind and inhibit the ubiquitous transport enzyme sodium potassium pump, thus regulating intracellular Na(+) concentration in every living cell. Although digoxin has been prescribed to heart failure patients for at least 200 years, the realization that CTS are endogenously produced has intensified research into their physiological and pathophysiological roles. Over the last two decades, substantial evidence has accumulated demonstrating the effects of endogenously synthesised CTS on the kidneys, vasculature and the heart. In this review, the current state of art and the controversies surrounding the manner in which CTS mediate their pathophysiological effects are discussed. Several potential therapeutic strategies have emerged as a result of our increased understanding of the role CTS play in health and disease.
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Affiliation(s)
- Davor Pavlovic
- Cardiovascular Division, King's College London, Rayne Institute, St. Thomas' Hospital, London, UK
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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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