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Fernández ÁF, Liu Y, Ginet V, Shi M, Nah J, Zou Z, Zhou A, Posner BA, Xiao G, Tanguy M, Paradis V, Sadoshima J, Rautou PE, Puyal J, Hu MC, Levine B. Interaction between the autophagy protein Beclin 1 and Na+,K+-ATPase during starvation, exercise, and ischemia. JCI Insight 2020; 5:133282. [PMID: 31941841 DOI: 10.1172/jci.insight.133282] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/04/2019] [Indexed: 01/26/2023] Open
Abstract
Autosis is a distinct form of cell death that requires both autophagy genes and the Na+,K+-ATPase pump. However, the relationship between the autophagy machinery and Na+,K+-ATPase is unknown. We explored the hypothesis that Na+,K+-ATPase interacts with the autophagy protein Beclin 1 during stress and autosis-inducing conditions. Starvation increased the Beclin 1/Na+,K+-ATPase interaction in cultured cells, and this was blocked by cardiac glycosides, inhibitors of Na+,K+-ATPase. Increases in Beclin 1/Na+,K+-ATPase interaction were also observed in tissues from starved mice, livers of patients with anorexia nervosa, brains of neonatal rats subjected to cerebral hypoxia-ischemia (HI), and kidneys of mice subjected to renal ischemia/reperfusion injury (IRI). Cardiac glycosides blocked the increased Beclin 1/Na+,K+-ATPase interaction during cerebral HI injury and renal IRI. In the mouse renal IRI model, cardiac glycosides reduced numbers of autotic cells in the kidney and improved clinical outcome. Moreover, blockade of endogenous cardiac glycosides increased Beclin 1/Na+,K+-ATPase interaction and autotic cell death in mouse hearts during exercise. Thus, Beclin 1/Na+,K+-ATPase interaction is increased in stress conditions, and cardiac glycosides decrease this interaction and autosis in both pathophysiological and physiological settings. This crosstalk between cellular machinery that generates and consumes energy during stress may represent a fundamental homeostatic mechanism.
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Affiliation(s)
- Álvaro F Fernández
- Center for Autophagy Research.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Yang Liu
- Center for Autophagy Research.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Vanessa Ginet
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Mingjun Shi
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jihoon Nah
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Zhongju Zou
- Center for Autophagy Research.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Howard Hughes Medical Institute
| | | | | | - Guanghua Xiao
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Marion Tanguy
- Centre de Recherche sur l'Inflammation, Université de Paris, Paris, France.,Service d'Hépatologie, Pôle des Maladies de l'Appareil Digestif, Département Hospitalo-Universitaire Unity, and
| | - Valérie Paradis
- Centre de Recherche sur l'Inflammation, Université de Paris, Paris, France.,Service d'Anatomie Pathologique, Hôpital Beaujon, Assistance Hôpitaux Publique de Paris, Clichy, France
| | - Junichi Sadoshima
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Pierre-Emmanuel Rautou
- Centre de Recherche sur l'Inflammation, Université de Paris, Paris, France.,Service d'Hépatologie, Pôle des Maladies de l'Appareil Digestif, Département Hospitalo-Universitaire Unity, and
| | - Julien Puyal
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Ming Chang Hu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Beth Levine
- Center for Autophagy Research.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Howard Hughes Medical Institute
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Makris EA, Huang BJ, Hu JC, Chen-Izu Y, Athanasiou KA. Digoxin and adenosine triphosphate enhance the functional properties of tissue-engineered cartilage. Tissue Eng Part A 2014; 21:884-94. [PMID: 25473799 DOI: 10.1089/ten.tea.2014.0360] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Toward developing engineered cartilage for the treatment of cartilage defects, achieving relevant functional properties before implantation remains a significant challenge. Various chemical and mechanical stimuli have been used to enhance the functional properties of engineered musculoskeletal tissues. Recently, Ca(2+)-modulating agents have been used to enhance matrix synthesis and biomechanical properties of engineered cartilage. The objective of this study was to determine whether other known Ca(2+) modulators, digoxin and adenosine triphosphate (ATP), can be employed as novel stimuli to increase collagen synthesis and functional properties of engineered cartilage. Neocartilage constructs were formed by scaffold-free self-assembling of primary bovine articular chondrocytes. Digoxin, ATP, or both agents were added to the culture medium for 1 h/day on days 10-14. After 4 weeks of culture, neocartilage properties were assessed for gross morphology, biochemical composition, and biomechanical properties. Digoxin and ATP were found to increase neocartilage collagen content by 52-110% over untreated controls, while maintaining proteoglycan content near native tissue values. Furthermore, digoxin and ATP increased the tensile modulus by 280% and 180%, respectively, while the application of both agents increased the modulus by 380%. The trends in tensile properties were found to correlate with the amount of collagen cross-linking. Live Ca(2+) imaging experiments revealed that both digoxin and ATP were able to increase Ca(2+) oscillations in monolayer-cultured chondrocytes. This study provides a novel approach toward directing neocartilage maturation and enhancing its functional properties using novel Ca(2+) modulators.
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Affiliation(s)
- Eleftherios A Makris
- 1 Department of Biomedical Engineering, University of California Davis , Davis, California
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Abstract
Digoxin and digitoxin are widely used in the treatment of heart diseases. The exact mechanism of action of these drugs has remained an enigma. Ouabain has become the standard tool to investigate the mode of action of cardiotonic steroids, and results with ouabain are regarded as generally valid for all cardiac glycosides. However, there are marked differences between the effects of ouabain and digitalis glycosides. Ouabain has a different therapeutic profile from digitalis derivatives. Unlike digitalis glycosides, ouabain has a fast onset of action and stimulates myocardial metabolism. The inotropic effect of cardiotonic steroids is not related to inhibition of the Na-K-ATPase. Ouabain and digitalis derivatives develop their effects in different cellular spaces. Digitalis glycosides increase the intracellular calcium concentration by entering the cell interior and acting on the ryanodine receptors and by forming transmembrane calcium channels. Ouabain, by activation of the Na-K-ATPase from the extracellular side, triggers release of calcium from intracellular stores via signal transduction pathways and activates myocardial metabolism. These data no longer support the concept that all cardiotonic steroids exhibit their therapeutic effects by partial inhibition of the ion-pumping function of the Na-K-ATPase. Hence, it is suggested that this deeply rooted dogma be revised.
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Schoner W, Scheiner-Bobis G. Endogenous and exogenous cardiac glycosides: their roles in hypertension, salt metabolism, and cell growth. Am J Physiol Cell Physiol 2007; 293:C509-36. [PMID: 17494630 DOI: 10.1152/ajpcell.00098.2007] [Citation(s) in RCA: 337] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cardiotonic steroids (CTS), long used to treat heart failure, are endogenously produced in mammals. Among them are the hydrophilic cardenolide ouabain and the more hydrophobic cardenolide digoxin, as well as the bufadienolides marinobufagenin and telecinobufagin. The physiological effects of endogenous ouabain on blood pressure and cardiac activity are consistent with the "Na(+)-lag" hypothesis. This hypothesis assumes that, in cardiac and arterial myocytes, a CTS-induced local increase of Na(+) concentration due to inhibition of Na(+)/K(+)-ATPase leads to an increase of intracellular Ca(2+) concentration ([Ca(2+)](i)) via a backward-running Na(+)/Ca(2+) exchanger. The increase in [Ca(2+)](i) then activates muscle contraction. The Na(+)-lag hypothesis may best explain short-term and inotropic actions of CTS. Yet all data on the CTS-induced alteration of gene expression are consistent with another hypothesis, based on the Na(+)/K(+)-ATPase "signalosome," that describes the interaction of cardiac glycosides with the Na(+) pump as machinery activating various signaling pathways via intramembrane and cytosolic protein-protein interactions. These pathways, which may be activated simultaneously or selectively, elevate [Ca(2+)](i), activate Src and the ERK1/2 kinase pathways, and activate phosphoinositide 3-kinase and protein kinase B (Akt), NF-kappaB, and reactive oxygen species. A recent development indicates that new pharmaceuticals with antihypertensive and anticancer activities may be found among CTS and their derivatives: the antihypertensive rostafuroxin suppresses Na(+) resorption and the Src-epidermal growth factor receptor-ERK pathway in kidney tubule cells. It may be the parent compound of a new principle of antihypertensive therapy. Bufalin and oleandrin or the cardenolide analog UNBS-1450 block tumor cell proliferation and induce apoptosis at low concentrations in tumors with constitutive activation of NF-kappaB.
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Affiliation(s)
- Wilhelm Schoner
- Institut für Biochemie und Endokrinologie, Fachbereich Veterinärmedizin, Justus-Liebig-Universität Giessen, Frankfurter Str 100, Giessen, Germany.
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Deutsch J, Jang HG, Mansur N, Ilovich O, Shpolansky U, Galili D, Feldman T, Rosen H, Lichtstein D. 4-(3‘α15‘β-Dihydroxy-5‘β-estran-17‘β-yl)furan-2-methyl Alcohol: An Anti-Digoxin Agent with a Novel Mechanism of Action. J Med Chem 2005; 49:600-6. [PMID: 16420045 DOI: 10.1021/jm0505819] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis and some pharmacological properties of 4-(3'alpha-15'beta-dihydroxy-5beta-estran-17'beta-yl)furan-2-methyl alcohol (16) have been described. The compound was synthesized by reacting a synthetic 3alpha- benzyloxy-5beta-estr-15-en-17-one with the ethylene acetal of 4-bromo-2-furancarboxyaldehyde, followed by hydrolysis of the ethylene acetal and reduction of the aldehyde. Despite its resemblance to the structure of cardiac steroids (CS), 16 does not bind to the CS receptor on Na(+),K(+)-ATPase and does not increase the force of contraction of heart muscle. However, 16 inhibited the digoxin-induced increase in the force of contraction and arrhythmias in guinea pig papillary muscle and human atrial appendages. The steroid also inhibited digoxin-induced alteration in endocytosed membrane traffic, indicating a novel mechanism of action.
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Affiliation(s)
- Joseph Deutsch
- Department of Medicinal Chemistry, School of Pharmacy, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
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