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Leite JA, Pôças E, Maia GS, Barbosa L, Quintas LEM, Kawamoto EM, da Silva MLC, Scavone C, de Carvalho LED. Effect of ouabain on calcium signaling in rodent brain: A systematic review of in vitro studies. Front Pharmacol 2022; 13:916312. [PMID: 36105192 PMCID: PMC9465813 DOI: 10.3389/fphar.2022.916312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 07/20/2022] [Indexed: 11/26/2022] Open
Abstract
The Na+/K+-ATPase is an integral membrane ion pump, essential to maintaining osmotic balance in cells in the presence of cardiotonic steroids; more specifically, ouabain can be an endogenous modulator of the Na+/K+-ATPase. Here, we conducted a systematic review of the in vitro effects of cardiotonic steroids on Ca2+ in the brain of rats and mice. Methods: The review was carried out using the PubMed, Virtual Health Library, and EMBASE databases (between 12 June 2020 and 30 June 2020) and followed the guidelines described in the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). Results: in total, 829 references were identified in the electronic databases; however, only 20 articles were considered, on the basis of the inclusion criteria. The studies demonstrated the effects of ouabain on Ca2+ signaling in synaptosomes, brain slices, and cultures of rat and mouse cells. In addition to the well-known cytotoxic effects of high doses of ouabain, resulting from indirect stimulation of the reverse mode of the Na+/Ca2+ exchanger and increased intracellular Ca2+, other effects have been reported. Ouabain-mediated Ca2+ signaling was able to act increasing cholinergic, noradrenergic and glutamatergic neurotransmission. Furthermore, ouabain significantly increased intracellular signaling molecules such as InsPs, IP3 and cAMP. Moreover treatment with low doses of ouabain stimulated myelin basic protein synthesis. Ouabain-induced intracellular Ca2+ increase may promote the activation of important cell signaling pathways involved in cellular homeostasis and function. Thus, the study of the application of ouabain in low doses being promising for application in neurological diseases. Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020204498, identifier CRD42020204498.
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Affiliation(s)
- Jacqueline Alves Leite
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Elisa Pôças
- Campus Realengo, Instituto Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gisele Silva Maia
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São Paulo, Brazil
| | - Leandro Barbosa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São Paulo, Brazil
| | - Luis Eduardo M. Quintas
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Elisa Mitiko Kawamoto
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | | | - Cristoforo Scavone
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Luciana E. Drumond de Carvalho
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São Paulo, Brazil
- *Correspondence: Luciana E. Drumond de Carvalho,
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Dubrovskii VN, Orlova LA. Effect of Detergents on Activity and Magnesium-Dependent Properties of Different Isoforms of Na +,K +-ATPase in the Crude Membrane Fraction of Rat Cerebral Cortex. Bull Exp Biol Med 2021; 171:611-614. [PMID: 34617174 DOI: 10.1007/s10517-021-05279-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Indexed: 11/28/2022]
Abstract
We studied the effect of various detergents (Tween-20, Triton X-100, and sodium deoxycholate) on activity and magnesium-dependent properties of Na+,K+-ATPase of the crude membrane fraction of rat cerebral cortex. All studied detergents significantly increased activity of the studied enzyme in a concentration-dependent manner. Sodium deoxycholate provided significantly higher values Na+,K+-ATPase activity (by ≈50%) than Triton X-100 and Tween-20. In the presence of Triton X-100, a changed pattern of the dependence of enzyme activity on the concentration of magnesium ions in the incubation solution was noted. Separate measurement of activities of Na+,K+-ATPase isoforms made it possible to assume that changes in magnesium-dependent properties are due to the predominant effect of Triton X-100 on ouabain-sensitive α2- and α3-isoforms.
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Moraes CM, Lucena MN, Garçon DP, Pinto MR, Fabri LM, Faleiros RO, Fontes CFL, McNamara JC, Leone FA. Biochemical Characterization and Allosteric Modulation by Magnesium of (Na +, K +)-ATPase Activity in the Gills of the Red Mangrove Crab Goniopsis cruentata (Brachyura, Grapsidae). J Membr Biol 2020; 253:229-245. [PMID: 32440867 DOI: 10.1007/s00232-020-00120-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 05/02/2020] [Indexed: 11/26/2022]
Abstract
We provide a kinetic characterization of (Na+, K+)-ATPase activity in a posterior gill microsomal fraction from the grapsid crab Goniopsis cruentata. (Na+, K+)-ATPase activity constitutes 95% of total ATPase activity, and sucrose density centrifugation reveals an ATPase activity peak between 25 and 35% sucrose, distributed into two, partially separated protein fractions. The (Na+, K+)-ATPase α-subunit is localized throughout the ionocyte cytoplasm and has an Mr of ≈ 10 kDa and hydrolyzes ATP obeying cooperative kinetics. Low (VM = 186.0 ± 9.3 nmol Pi min-1 mg-1 protein and K0.5 = 0.085 ± 0.004 mmol L-1) and high (VM = 153.4 ± 7.7 nmol Pi min-1 mg-1 protein and K0.5 = 0.013 ± 0.0006 mmol L-1) affinity ATP binding sites were characterized. At low ATP concentrations, excess Mg2+ stimulates the enzyme, triggering exposure of a high-affinity binding site that accounts for 50% of (Na+, K+)-ATPase activity. Stimulation by Mg2+ (VM = 425.9 ± 25.5 nmol Pi min-1 mg-1 protein, K0.5 = 0.16 ± 0.01 mmol L-1), K+ (VM = 485.3 ± 24.3 nmol Pi min-1 mg-1 protein, K0.5 = 0.9 ± 0.05 mmol L-1), Na+ (VM = 425.0 ± 23.4 nmol Pi min-1 mg-1 protein, K0.5 = 5.1 ± 0.3 mmol L-1) and NH4+ (VM = 497.9 ± 24.9 nmol Pi min-1 mg-1 protein, K0.5 = 9.7 ± 0.5 mmol L-1) obeys cooperative kinetics. Ouabain inhibits up to 95% of ATPase activity with KI = 196.6 ± 9.8 µmol L-1. This first kinetic characterization of the gill (Na+, K+)-ATPase in Goniopsis cruentata enables better comprehension of the biochemical underpinnings of osmoregulatory ability in this semi-terrestrial mangrove crab.
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Affiliation(s)
- Cintya M Moraes
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, SP, 14040-901, Brazil
| | - Malson N Lucena
- Instituto de Biociências, Universidade Federal do Mato Grosso do Sul, Campo Grande, MS, Brazil
| | | | - Marcelo R Pinto
- Laboratório de Biopatologia e Biologia Molecular Universidade Uberaba, Uberaba, MG, Brazil
| | - Leonardo M Fabri
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, SP, 14040-901, Brazil
| | - Rogério O Faleiros
- Departamento de Ciências Agrárias e Biológicas, Universidade Federal do Espírito Santo, São Mateus, ES, Brazil
| | - Carlos F L Fontes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - John C McNamara
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
- Centro de Biologia Marinha, Universidade de São Paulo, São Sebastião, SP, Brazil
| | - Francisco A Leone
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, SP, 14040-901, Brazil.
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Pereira DG, Rendeiro MM, Cortes VF, Barbosa LA, Quintas LEM. Antagonistic anticancer effect of paclitaxel and digoxin combination. J Cell Biochem 2019; 120:13107-13114. [PMID: 30883884 DOI: 10.1002/jcb.28583] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/23/2019] [Accepted: 01/28/2019] [Indexed: 12/21/2022]
Abstract
Despite the growing interest in the antitumor effect of cardiotonic steroids, combination treatments with well-established chemotherapy drugs like paclitaxel have been rarely investigated. Moreover, paclitaxel has been suggested as a Na+ /K+ -ATPase inhibitor. Here we investigated the effect of paclitaxel and digoxin alone or in combination on the viability of human lung (A549) and cervical cancer (HeLa) cell lines and the inhibitory effect of paclitaxel on several mammalian Na+ /K+ -ATPases. Although the viability of both tumor cell lines was concentration-dependently affected by digoxin treatment after 48 hours (A549 IC50 = 31 nM and HeLa IC50 = 151 nM), a partial effect was observed for paclitaxel, with a maximal inhibitory effect of 45% at 1000 nM with A549 and around 70% with HeLa cells (IC50 = 1 nM). Although the two drugs were cytotoxic, their combined effect in HeLa cells was revealed to be antagonistic, as estimated by the combination index. No direct inhibitory effect of paclitaxel was detected in human, pig, rat, and mouse Na+ /K+ -ATPase enzymes, but high concentrations of paclitaxel decreased the Na+ /K+ -ATPase activity in HeLa cells after 48 hours without affecting protein expression. Our findings demonstrate that, under our conditions, paclitaxel and digoxin cotreatment produce antagonistic cytotoxic effects in HeLa cells, and the mechanism of action of paclitaxel does not involve a direct inhibition of Na+ /K+ -ATPase. More studies shall be designed to evaluate the consequences of the interaction of cardiotonic steroids and chemotherapy drugs.
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Affiliation(s)
- Duane Gischewski Pereira
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindú, Divinópolis, Brazil
| | - Mariana Manzano Rendeiro
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vanessa Faria Cortes
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindú, Divinópolis, Brazil
| | - Leandro Augusto Barbosa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindú, Divinópolis, Brazil
| | - Luis Eduardo M Quintas
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Fabri LM, Lucena MN, Garçon DP, Moraes CM, McNamara JC, Leone FA. Kinetic characterization of the gill (Na+, K+)-ATPase in a hololimnetic population of the diadromous Amazon River shrimp Macrobrachium amazonicum (Decapoda, Palaemonidae). Comp Biochem Physiol B Biochem Mol Biol 2019; 227:64-74. [DOI: 10.1016/j.cbpb.2018.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 09/18/2018] [Indexed: 10/28/2022]
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Noël F, Azalim P, do Monte FM, Quintas LEM, Katz A, Karlish SJ. Revisiting the binding kinetics and inhibitory potency of cardiac glycosides on Na+,K+-ATPase (α1β1): Methodological considerations. J Pharmacol Toxicol Methods 2018; 94:64-72. [DOI: 10.1016/j.vascn.2018.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/30/2018] [Accepted: 09/18/2018] [Indexed: 12/12/2022]
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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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Ben-Ari H, Paz M, Sher D. The chemical armament of reef-building corals: inter- and intra-specific variation and the identification of an unusual actinoporin in Stylophora pistilata. Sci Rep 2018; 8:251. [PMID: 29321526 PMCID: PMC5762905 DOI: 10.1038/s41598-017-18355-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 12/04/2017] [Indexed: 01/20/2023] Open
Abstract
Corals, like other cnidarians, are venomous animals that rely on stinging cells (nematocytes) and their toxins to catch prey and defend themselves against predators. However, little is known about the chemical arsenal employed by stony corals, despite their ecological importance. Here, we show large differences in the density of nematocysts and whole-body hemolytic activity between different species of reef-building corals. In the branched coral Stylophora pistillata, the tips of the branches exhibited a greater hemolytic activity than the bases. Hemolytic activity and nematocyst density were significantly lower in Stylophora that were maintained for close to a year in captivity compared to corals collected from the wild. A cysteine-containing actinoporin was identified in Stylophora following partial purification and tandem mass spectrometry. This toxin, named Δ-Pocilopotoxin-Spi1 (Δ-PCTX-Spi1) is the first hemolytic toxin to be partially isolated and characterized in true reef-building corals. Loss of hemolytic activity during chromatography suggests that this actinoporin is only one of potentially several hemolytic molecules. These results suggest that the capacity to employ offensive and defensive chemicals by corals is a dynamic trait within and between coral species, and provide a first step towards identifying the molecular components of the coral chemical armament.
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Affiliation(s)
- Hanit Ben-Ari
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel.,The Interuniversity Institute for Marine Sciences, Eilat, Israel
| | - Moran Paz
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Daniel Sher
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel.
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Properties of Na,K-ATPase in cerebellum of male and female rats: effects of acute and prolonged diabetes. Mol Cell Biochem 2016; 425:25-36. [DOI: 10.1007/s11010-016-2859-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 10/22/2016] [Indexed: 02/07/2023]
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10
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Perera Córdova WH, Leitão SG, Cunha-Filho G, Bosch RA, Alonso IP, Pereda-Miranda R, Gervou R, Touza NA, Quintas LEM, Noël F. Bufadienolides from parotoid gland secretions of Cuban toad Peltophryne fustiger (Bufonidae): Inhibition of human kidney Na(+)/K(+)-ATPase activity. Toxicon 2015; 110:27-34. [PMID: 26615828 DOI: 10.1016/j.toxicon.2015.11.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/24/2015] [Accepted: 11/18/2015] [Indexed: 12/22/2022]
Abstract
Parotoid gland secretions of toad species are a vast reservoir of bioactive molecules with a wide range of biological properties. Herein, for the first time, it is described the isolation by preparative reversed-phase HPLC and the structure elucidation by NMR spectroscopy and/or mass spectrometry of nine major bufadienolides from parotoid gland secretions of the Cuban endemic toad Peltophryne fustiger: ψ-bufarenogin, gamabufotalin, bufarenogin, arenobufagin, 3-(N-suberoylargininyl) marinobufagin, bufotalinin, telocinobufagin, marinobufagin and bufalin. In addition, the secretion was analyzed by UPLC-MS/MS which also allowed the identification of azelayl arginine. The effect of arenobufagin, bufalin and ψ-bufarenogin on Na(+)/K(+)-ATPase activity in a human kidney preparation was evaluated. These bufadienolides fully inhibited the Na(+)/K(+)-ATPase in a concentration-dependent manner, although arenobufagin (IC50 = 28.3 nM) and bufalin (IC50 = 28.7 nM) were 100 times more potent than ψ-bufarenogin (IC50 = 3020 nM). These results provided evidence about the importance of the hydroxylation at position C-14 in the bufadienolide skeleton for the inhibitory activity on the Na(+)/K(+)-ATPase.
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Affiliation(s)
- Wilmer H Perera Córdova
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, Bloco A,Ilha do Fundão, 21.941-590 Rio de Janeiro, Brazil.
| | - Suzana Guimarães Leitão
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, Bloco A,Ilha do Fundão, 21.941-590 Rio de Janeiro, Brazil
| | - Geraldino Cunha-Filho
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, CCS Bloco J, Ilha do Fundão, 21941-902, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Roberto Alonso Bosch
- Facultad de Biología, Universidad de La Habana, Calle 25 No. 455, Vedado, Havana City, Cuba
| | - Isel Pascual Alonso
- Facultad de Biología, Universidad de La Habana, Calle 25 No. 455, Vedado, Havana City, Cuba
| | - Rogelio Pereda-Miranda
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, 04510 DF, Mexico
| | - Rodrigo Gervou
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, CCS Bloco J, Ilha do Fundão, 21941-902, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Natália Araújo Touza
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, CCS Bloco J, Ilha do Fundão, 21941-902, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luis Eduardo M Quintas
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, CCS Bloco J, Ilha do Fundão, 21941-902, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - François Noël
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, CCS Bloco J, Ilha do Fundão, 21941-902, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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The (Na(+)/K (+))-ATPase activity in the developing rat retina: the role of insulin-like growth factor-I (IGF-I). Cell Mol Neurobiol 2014; 35:243-54. [PMID: 25274047 DOI: 10.1007/s10571-014-0119-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 09/23/2014] [Indexed: 02/04/2023]
Abstract
In this work, the (Na(+)/K(+))-ATPase activity was evaluated during the early stages of the postnatal development of rat retina and showed an almost three-time increase from P0 to P14. Expression of the three catalytic subunit isoforms (α1, α2, and α3) of the (Na(+)/K(+))-ATPase was also evaluated by immunoblot in the same period, but no correlation to the catalytic activity increment was observed. On the other hand, immunolocalization of these three α-catalytic isoforms in the developing retina showed an age-related pattern. Involvement of IGF-I in the stimulation of the (Na(+)/K(+))-ATPase was investigated. Our results demonstrate that the exogenous IGF-I (10 ng/mL) stimulates enzyme activity at the age of P7 only. Incubation of retinas with 10 μM I-OMe-AG 538 (inhibitor of the IGF-I receptor) indicates that the basal (Na(+)/K(+))-ATPase activity is sustained by endogenous IGF-I in P7 animals. These data were corroborated by an age-dependent decrease in the immunodetection of endogenous IGF-I as well as in the phosphorylation level of its cognate receptor in rat retina homogenates. The signaling pathway involved in IGF-I-induced modulation of the (Na(+)/K(+))-ATPase was also investigated. Our data show that the inhibitory effects induced by I-OMe-AG 538 and the PI 3-kinase inhibitor Ly 294002 on the basal (Na(+)/K(+))-ATPase activity were non-cumulative. Furthermore, IGF-I induced phosphorylation of PKB in a Ly 294002-sensitive manner. Together, these data demonstrate that the PI 3-kinase/PKB signaling pathway is involved in the IGF-I-sustained basal (Na(+)/K(+))-ATPase activity during the first 7 days of the postnatal development of rat retina.
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França JL, Pinto MR, Lucena MN, Garçon DP, Valenti WC, McNamara JC, Leone FA. Subcellular Localization and Kinetic Characterization of a Gill (Na+, K+)-ATPase from the Giant Freshwater Prawn Macrobrachium rosenbergii. J Membr Biol 2013; 246:529-43. [DOI: 10.1007/s00232-013-9565-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 05/31/2013] [Indexed: 10/26/2022]
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Abstract
Administration of chemotherapy during pregnancy may represent a big risk factor for the developing brain, therefore we studied whether the transplacental transport of doxorubicin (DOX) may affect the development of neuroendocrine system. DOX (25 mg/kg; 3 times interaperitoneally/week) was given to pregnant rats during whole gestation period. The disturbances in neuroendocrine functions were investigated at gestation day (GD) 15 and 20 by following the maternal and fetal thyroid hormone levels, fetal nucleotides (ATP, ADP, AMP) levels and adenosine triphosphatase (Na(+), K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase) activities in two brain regions, cerebrum and cerebellum. In control group, the levels of maternal and fetal serum thyroxine (T4), triiodothyronine (T3), thyrotropin (TSH), and fetal serum growth hormone (GH) increased from days 15 to 20, whereas in the DOX group, a decrease in maternal and fetal T4, T3 and increase in TSH levels (hypothyroid status) were observed. Also, the levels of fetal GH decreased continuously from GD 15 to 20 with respect to control group. In cerebrum and cerebellum, the levels of fetal nucleotides and the activities of fetal ATPases in control group followed a synchronized course of development. The fetal hypothyroidism due to maternal administration of DOX decreased the levels of nucleotides, ATPases activities, and total adenylate, instead, the adenylate energy charge showed a trend to an increase in both brain regions at all ages tested. These alterations were dose- and age-dependent and this, in turn, may impair the nerve transmission. Finally, DOX may act as neuroendocrine disruptor causing hypothyroidism and fetal brain energetic dysfunction.
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Lucas TFG, Amaral LS, Porto CS, Quintas LEM. Na+/K+-ATPase α1 isoform mediates ouabain-induced expression of cyclin D1 and proliferation of rat sertoli cells. Reproduction 2012; 144:737-45. [PMID: 23028124 DOI: 10.1530/rep-12-0232] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Novel roles for the interaction of cardiotonic steroids to Na(+)/K(+)-ATPase have been established in recent years. The aim of this study was to investigate the intracellular signaling events downstream the action of ouabain on Na(+)/K(+)-ATPase in Sertoli cell obtained from immature rats. Treatment of Sertoli cells with ouabain (1 μM) induced a rapid and transient increase in the extracellular signal-regulated kinase (ERK1/2 or MAPK3/1) and phosphatidylinositol 3-kinase (PI3K)/serine-threonine protein kinase (AKT) phosphorylation. Also, ouabain upregulated the expression of cyclin D1 and incorporation of [methyl-(3)H]thymidine, both of which were dependent on MAPK3/1 but not AKT intracellular cascade, as shown by pretreatment with MEK (MAP2K1/2) inhibitor U0126 and PI3K inhibitor wortmannin respectively. Moreover, the effect of ouabain on these proliferation parameters was completely prevented by phospho-cAMP response element-binding protein (CREB)/CREB-binding protein complex inhibitor KG501 and only partially by nuclear factor κB nuclear translocation inhibitor SN50. Pretreatment with estrogen receptor antagonist ICI 182780 showed that MAPK3/1 activation by ouabain does not involve this receptor. The Na(+)/K(+)-ATPase α1 isoform, but not α4, was detected in Sertoli cells, suggesting that ouabain effects in Sertoli cells are mediated via α1. Taken together, these results show a rapid ouabain action in the Sertoli cells, which in turn can modulate nuclear transcriptional events essential for Sertoli cell proliferation in a critical period of testicular development. Our findings are important to understand the role of ouabain in the testis and its possible implications in male infertility.
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Affiliation(s)
- Thaís F G Lucas
- Setor de Endocrinologia Experimental, Departamento de Farmacologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, São Paulo, Brazil
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Lucena MN, Garçon DP, Mantelatto FL, Pinto MR, McNamara JC, Leone FA. Hemolymph ion regulation and kinetic characteristics of the gill (Na+, K+)-ATPase in the hermit crab Clibanarius vittatus (Decapoda, Anomura) acclimated to high salinity. Comp Biochem Physiol B Biochem Mol Biol 2012; 161:380-91. [DOI: 10.1016/j.cbpb.2012.01.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 12/05/2011] [Accepted: 01/05/2012] [Indexed: 10/14/2022]
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Weidemann H. "The Lower Threshold" phenomenon in tumor cells toward endogenous digitalis-like compounds: Responsible for tumorigenesis? J Carcinog 2012; 11:2. [PMID: 22438768 PMCID: PMC3307333 DOI: 10.4103/1477-3163.92999] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 12/01/2011] [Indexed: 02/06/2023] Open
Abstract
Since their first discovery as potential anti-cancer drugs decades ago, there is increasing evidence that digitalis-like compounds (DLC) have anti-tumor effects. Less is known about endogenous DLC (EDLC) metabolism and regulation. As stress hormones synthesized in and secreted from the adrenal gland, they likely take part in the hypothalamo-pituitary-adrenal (HPA) axis. In a previous study, we revealed reduced EDLC concentrations in plasma and organs from immune-compromised animals and proposed that a similar situation of a deregulated HPA axis with "adrenal EDLF exhaustion" may contribute to tumorigenesis in chronic stress situations. Here, we put forward the hypothesis that a lowered EDLC response threshold of tumor cells as compared with normal cells increases the risk of tumorigenesis, especially in those individuals with reduced EDLC plasma concentrations after chronic stress exposure. We will evaluate this hypothesis by (a) summarizing the effects of different DLC concentrations on tumor as compared with normal cells and (b) reviewing some essential differences in the Na/K-ATPase of tumor as compared with normal cells (isoform pattern, pump activity, mutations of other signalosome receptors). We will conclude that (1) tumor cells, indeed, seem to have their individual "physiologic" EDLC response range that already starts at pmolar levels and (2) that individuals with markedly reduced (pmolar) EDLC plasma levels are predisposed to cancer because these EDLC concentrations will predominantly stimulate the proliferation of tumor cells. Finally, we will summarize preliminary results from our department supporting this hypothesis.
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Affiliation(s)
- Heidrun Weidemann
- Department of Oncology, Hadassah-Hebrew University, Medical Center, Jerusalem, Israel
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Touza NA, Pôças ESC, Quintas LEM, Cunha-Filho G, Santos ML, Noël F. Inhibitory effect of combinations of digoxin and endogenous cardiotonic steroids on Na+/K+-ATPase activity in human kidney membrane preparation. Life Sci 2011; 88:39-42. [DOI: 10.1016/j.lfs.2010.10.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Revised: 09/22/2010] [Accepted: 10/19/2010] [Indexed: 09/30/2022]
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18
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Noël F, Pimenta PHC, Dos Santos AR, Tomaz ECL, Quintas LEM, Kaiser CR, Silva CLM, Férézou JP. Δ²,³-ivermectin ethyl secoester, a conjugated ivermectin derivative with leishmanicidal activity but without inhibitory effect on mammalian P-type ATPases. Naunyn Schmiedebergs Arch Pharmacol 2010; 383:101-7. [PMID: 21088826 DOI: 10.1007/s00210-010-0578-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 10/28/2010] [Indexed: 10/18/2022]
Abstract
Looking at a new putative target for the large spectrum antiparasitic drug ivermectin, we recently showed that avermectin-derived drugs are active against promastigote and amastigote forms of Leishmania amazonensis at low micromolar concentrations. However, we then reported that at this concentration range ivermectin is also able to inhibit three important mammalian P-type ATPases so that unacceptable adverse effects could occur if this drug were used at such high doses therapeutically. The present work aimed to test the activity of ten ivermectin analogs on these rat ATPases in search of a compound with similar leishmanicidal activity but with no effect on the mammalian (host) ATPases at effective concentrations. We synthesized three new ivermectin analogs for testing on rat SERCA (1a and 1b), Na+, K+-ATPase (α₁ and α₂/α₃ isoforms) and H+/K+-ATPase activity, along with seven analogs already characterized for their leishmanicidal activity. Our main finding is that one of the prepared derivatives, Δ²,³-ivermectin ethyl secoester 8, is equipotent to ivermectin 1 for the in vitro leishmanicidal effects but is nearly without effect on the rat ATPases, indicating that it could have a better therapeutic index in vivo and could serve as a candidate for hit-to-lead progression. This conclusion is further supported by the fact that compound 8 produced only 6% (vs 77% for ivermectin) inhibition of the human kidney enzyme at 5 μM, a concentration corresponding to the IC₅₀ for the activity against L. amazonensis amastigotes.
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Affiliation(s)
- François Noël
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Bloco J-sala 17, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Av. Carlos Chagas Filho 373, CEP: 21941-902, Rio de Janeiro, RJ, Brazil.
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19
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Kim CR, Sadowska GB, Newton SA, Merino M, Petersson KH, Padbury JF, Stonestreet BS. Na+,K+-ATPase activity and subunit protein expression: ontogeny and effects of exogenous and endogenous steroids on the cerebral cortex and renal cortex of sheep. Reprod Sci 2010; 18:359-73. [PMID: 20959645 DOI: 10.1177/1933719110385137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We examined the effects of development, exogenous, and endogenous glucocorticoids on Na(+),K(+)-ATPase activity and subunit protein expression in ovine cerebral cortices and renal cortices. Ewes at 60%, 80%, and 90% gestation, newborns, and adults received 4 dexamethasone or placebo injections. Cerebral cortex Na(+),K(+)-ATPase activity was higher (P < .05) in placebo-treated newborns than fetuses of placebo-treated ewes and adults, α(1)-expression was higher at 90% gestation than the other ages; α(2)-expression was higher in newborns than fetuses; α(3)-expression was higher in newborns than 60% gestation; β(1)-expression was higher in newborns than the other ages, and β(2)-expression higher at 60% than 80% and 90% gestation, and in adults. Renal cortex Na(+),K(+)-ATPase activity was higher in placebo-treated adults and newborns than fetuses. Cerebral cortex Na(+),K(+)-ATPase activity was higher in dexamethasone- than placebo-treated adults, and α(1)-expression higher in fetuses of dexamethasone- than placebo-treated ewes at 60% and 80% gestation. Renal cortex Na(+),K(+)-ATPase activity and α(1)-expression were higher in fetuses of dexamethasone- than placebo-treated ewes at each gestational age, and β(1)-expression was higher in fetuses of dexamethasone- than placebo-treated ewes at 90% gestation and in dexamethasone- than placebo-treated adults. Cerebral cortex Na(+),K(+)-ATPase activity, α(1)-expression, β(1)-expression, and renal cortex α(1)-expression correlated directly with increases in fetal cortisol. In conclusion, Na(+),K(+)-ATPase activity and subunit expression exhibit specific developmental patterns in brain and kidney; exogenous glucocorticoids regulate activity and subunit expression in brain and kidney at some ages; endogenous increases in fetal cortisol regulate cerebral Na(+),K(+)-ATPase, but exogenous glucocorticoids have a greater effect on renal than cerebral Na(+),K(+)-ATPase.
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Affiliation(s)
- Chang-Ryul Kim
- Department of Pediatrics, Women and Infants Hospital of Rhode Island, The Warren Alpert Medical School of Brown University, Providence, RI 02905,USA
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20
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Barreto F, Rezende D, Scaramello C, Silva C, Cunha V, Caricati-Neto A, Jurkiewicz A, Noël F, Quintas L. Lack of evidence for regulation of cardiac P-type ATPases and MAP kinases in transgenic mice with cardiac-specific overexpression of constitutively active α1B-adrenoceptors. Braz J Med Biol Res 2010; 43:500-5. [DOI: 10.1590/s0100-879x2010007500028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 04/01/2010] [Indexed: 11/21/2022] Open
Affiliation(s)
- F. Barreto
- Universidade Federal do Rio de Janeiro, Brasil
| | | | | | | | | | | | | | - F. Noël
- Universidade Federal do Rio de Janeiro, Brasil
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21
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Schaffazick N, Amaral LS, Fonseca TF, Tomaz MA, Gaban GA, Borges PA, Calil-Elias S, Noël F, Melo PA, Quintas LEM, Cunha VM. Effect of heparin treatment on the expression and activity of different ion-motive P-type ATPase isoforms from mouse extensor digitorum longus muscle during degeneration and regeneration after Bothrops jararacussu venom injection. Toxicon 2010; 55:52-60. [DOI: 10.1016/j.toxicon.2009.06.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 06/26/2009] [Accepted: 06/26/2009] [Indexed: 12/17/2022]
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22
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Hemolymph ionic regulation and adjustments in gill (Na+, K+)-ATPase activity during salinity acclimation in the swimming crab Callinectes ornatus (Decapoda, Brachyura). Comp Biochem Physiol A Mol Integr Physiol 2009; 154:44-55. [DOI: 10.1016/j.cbpa.2009.04.624] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 04/27/2009] [Accepted: 04/27/2009] [Indexed: 11/23/2022]
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23
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Masui DC, Mantelatto FL, McNamara JC, Furriel RP, Leone FA. Na+, K+-ATPase activity in gill microsomes from the blue crab, Callinectes danae, acclimated to low salinity: Novel perspectives on ammonia excretion. Comp Biochem Physiol A Mol Integr Physiol 2009; 153:141-8. [DOI: 10.1016/j.cbpa.2009.01.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 01/28/2009] [Accepted: 01/28/2009] [Indexed: 11/17/2022]
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24
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Quintas LEM, Noël F. Mechanisms of adaptive supersensitivity in vas deferens. Auton Neurosci 2009; 146:38-46. [PMID: 19188094 DOI: 10.1016/j.autneu.2009.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2008] [Revised: 12/27/2008] [Accepted: 01/06/2009] [Indexed: 10/24/2022]
Abstract
Adaptive supersensitivity is a phenomenon characteristic of excitable tissues and discloses as a compensatory adjustment of tissue's response to unrelated stimulatory endogenous and exogenous substances after chronic interruption of excitatory neurotransmission. The mechanisms underlying such higher postjunctional sensitivity have been postulated for a variety of cell types. In smooth muscles, especially the vas deferens with its rich sympathetic innervation, the mechanisms responsible for supersensitivity are partly understood and appear to be different from one species to another. The present review provides a general understanding of adaptive supersensitivity and emphasizes early and recent information about the putative mechanisms involved in this phenomenon in rodent vas deferens.
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Affiliation(s)
- Luis Eduardo M Quintas
- Laboratório de Farmacologia Bioquímica e Molecular, ICB, Universidade Federal do Rio de Janeiro, Avenida Carlos Chagas Filho 373, J-17, Rio de Janeiro 21941-902, Brazil.
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25
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Silva VS, Nunes MA, Cordeiro JM, Calejo AI, Santos S, Neves P, Sykes A, Morgado F, Dunant Y, Gonçalves PP. Comparative effects of aluminum and ouabain on synaptosomal choline uptake, acetylcholine release and (Na+/K+)ATPase. Toxicology 2007; 236:158-77. [PMID: 17560001 DOI: 10.1016/j.tox.2007.04.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 03/16/2007] [Accepted: 04/10/2007] [Indexed: 11/25/2022]
Abstract
Closing the gap between adverse health effects of aluminum and its mechanisms of action still represents a huge challenge. Cholinergic dysfunction has been implicated in neuronal injury induced by aluminum. Previously reported data also indicate that in vivo and in vitro exposure to aluminum inhibits the mammalian (Na(+)/K(+))ATPase, an ubiquitous plasma membrane pump. This study was undertaken with the specific aim of determining whether in vitro exposure to AlCl(3) and ouabain, the foremost utilized selective inhibitor of (Na(+)/K(+))ATPase, induce similar functional modifications of cholinergic presynaptic nerve terminals, by comparing their effects on choline uptake, acetylcholine release and (Na(+)/K(+))ATPase activity, on subcellular fractions enriched in synaptic nerve endings isolated from rat brain, cuttlefish optic lobe and torpedo electric organ. Results obtained show that choline uptake by rat synaptosomes was inhibited by submillimolar AlCl(3), whereas the amount of choline taken up by synaptosomes isolated from cuttlefish and torpedo remained unchanged. Conversely, choline uptake was reduced by ouabain to a large extent in all synaptosomal preparations analyzed. In contrast to ouabain, which modified the K(+) depolarization evoked release of acetylcholine by rat, cuttlefish and torpedo synaptosomal fractions, AlCl(3) induced reduction of stimulated acetylcholine release was only observed when rat synaptosomes were challenged. Finally, it was observed that the aluminum effect on cuttlefish and torpedo synaptosomal (Na(+)/K(+))ATPase activity was slight when compared to its inhibitory action on mammalian (Na(+)/K(+))ATPase. In conclusion, inhibition of (Na(+)/K(+))ATPase by AlCl(3) and ouabain jeopardized the high-affinity (Na(+)-dependent, hemicholinium-3 sensitive) uptake of choline and the Ca(2+)-dependent, K(+) depolarization evoked release of acetylcholine by rat, cuttlefish and torpedo synaptosomal fractions. The effects of submillimolar AlCl(3) on choline uptake and acetylcholine release only resembled those of ouabain when rat synaptosomes were assayed. Therefore, important differences were found between the species regarding the cholinotoxic action of aluminum. The variability of (Na(+)/K(+))ATPase sensitivity to aluminum of cholinergic neurons might contribute to their differential susceptibility to this neurotoxic agent.
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Affiliation(s)
- Virgília S Silva
- CESAM, Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro, Portugal
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26
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Kim CR, Sadowska GB, Petersson KH, Merino M, Sysyn GD, Padbury JF, Stonestreet BS. Effects of postnatal steroids on Na+/K+-ATPase activity and alpha1- and beta1-subunit protein expression in the cerebral cortex and renal cortex of newborn lambs. Reprod Fertil Dev 2006; 18:413-23. [PMID: 16737634 DOI: 10.1071/rd05114] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Accepted: 01/02/2006] [Indexed: 11/23/2022] Open
Abstract
Na(+)/K(+)-ATPase is a membrane-bound enzyme responsible for Na(+)/K(+) translocation across cell membranes. It is essential for the generation of electrochemical gradients, which control the ionic environment necessary for electrical activity and water and electrolyte balance. Newborn infants who are at risk of developing bronchopulmonary dysplasia (BPD) are frequently treated with corticosteroids. Although these infants are at risk for neurological, water and electrolyte abnormalities, there is little information regarding the effects of clinically relevant doses of corticosteroids on Na(+)/K(+)-ATPase activity and protein isoform expression in the brain and kidney of newborns. In the present study, we examined the effects of dexamethasone on cerebral cortical and renal cortical Na(+)/K(+)-ATPase activity and alpha1- and beta1-protein isoform expression in newborn lambs. Lambs were given four injections of a placebo (n = 11) or one of three different doses of dexamethasone (0.01 mg kg(-1), n = 9; 0.25 mg kg(-1), n = 11; or 0.50 mg kg(-1), n = 9) 12 h apart on Postnatal Days 3 and 4 up to 18 h before harvest of the cerebral cortex and renal cortex. We selected doses in a range to approximate those used to treat infants with BPD. Na(+)/K(+)-ATPase activity was measured in membrane preparations as ouabain-sensitive inorganic phosphate liberation from ATP and alpha1- and beta1-subunit abundance by Western immunoblot. Postnatal treatment of lambs with dexamethasone resulted in a 21.4% increase in Na(+)/K(+)-ATPase activity and a 30.4% increase in catalytic alpha1-protein expression in the cerebral cortex at a dose of 0.50 mg kg(-1) dexamethasone, but not at the lower doses. Dexamethasone treatment was not associated with changes in beta1-isoform expression in the cerebral cortex. In the kidney, dexamethasone treatment was not associated with significant changes in Na(+)/K(+)-ATPase activity or alpha1- or beta1-isoform expression for the doses we examined. Therefore, clinically relevant corticosteroid treatment exerts dose-related, differential organ-specific effects on Na(+)/K(+)-ATPase activity and protein isoform expression in newborn lambs.
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Affiliation(s)
- Chang-Ryul Kim
- Pediatrics, Women & Infants' Hospital of Rhode Island and Brown Medical School, Providence, RI 02905-2499, USA
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27
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Silva VS, Duarte AI, Rego AC, Oliveira CR, Gonçalves PP. Effect of chronic exposure to aluminium on isoform expression and activity of rat (Na+/K+)ATPase. Toxicol Sci 2005; 88:485-94. [PMID: 16162844 DOI: 10.1093/toxsci/kfi324] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The ability of aluminum to inhibit the (Na(+)/K(+))ATPase activity has been observed by several investigators. The (Na(+)/K(+))ATPase is characterized by a complex molecular heterogeneity that results from the expression and differential association of multiple isoforms of both catalytic (alpha) and regulatory (beta) subunits. For instance, three main alpha (alpha(1), alpha(2) and alpha(3)) and three beta (beta(1), beta(2) and beta(3)) subunit isoforms exist in vertebrate nervous tissue, whereas only alpha(1) and beta(1) have been identified in kidney. However, no studies have focused on determining the change in (Na(+)/K(+))ATPase isoforms caused by chronic exposure to aluminum and its relation with aluminum toxicity. In this study, adult male Wistar rats were submitted to chronic dietary AlCl(3) exposure (0.03 g/day of AlCl(3) for 4 months), and the activity and protein expression of (Na(+)/K(+))ATPase isozymes were studied in brain cortex synaptosomes and in kidney homogenates. The intracellular levels of adenine nucleotides, plasma membrane integrity, and aluminum accumulation were also studied in brain synaptosomes. Aluminum accumulation upon chronic dietary AlCl(3) administration significantly decreased the (Na(+)/K(+))ATPase activity measured in the presence of nonlimiting Mg-ATP concentrations, without compromising protein expression of alpha-subunit isoforms in brain and kidney. Aluminum-induced synaptosomal (Na(+)/K(+))ATPase inhibition was due to a reduction in the activity of isozymes containing alpha(1)-alpha(2) and alpha(3)-subunits. The onset of enzyme inhibition was accompanied by a decrease of the (Na(+)/K(+))ATPase sensitivity to submicromolar concentrations of ouabain, and it preceded major damage in plasma membrane integrity and energy supply, as revealed by the analysis of lactate dehydrogenase leakage and endogenous adenine nucleotides. The data suggest that, during chronic dietary exposure to AlCl(3), brain (Na(+)/K(+))ATPase activity drops, even if no significant alterations of catalytic subunit protein expression, cellular energy depletion, and changes in cell membrane integrity are observed. Implications regarding underlying mechanisms of aluminum neurotoxicity are discussed.
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Affiliation(s)
- Virgília S Silva
- Centro de Estudos do Ambiente e Mar, Departamento de Biologia, Universidade de Aveiro, Portugal
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28
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Otsu K, Kuruma A, Yanagida E, Shoji S, Inoue T, Hirayama Y, Uematsu H, Hara Y, Kawano S. Na+/K+ ATPase and its functional coupling with Na+/Ca2+ exchanger in mouse embryonic stem cells during differentiation into cardiomyocytes. Cell Calcium 2005; 37:137-51. [PMID: 15589994 DOI: 10.1016/j.ceca.2004.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Revised: 05/25/2004] [Accepted: 08/06/2004] [Indexed: 12/15/2022]
Abstract
Cardiomyocytes derived from mouse embryonic stem (mES) cells have been demonstrated to exhibit a time-dependent expression of ion channels and signal transduction pathways in electrophysiological studies. However, ion transporters, such as Na+/K+ ATPase (Na+ pump) or Na+/Ca2+ exchanger, which play crucial roles for cardiac function, have not been well studied in this system. In this study, we investigated the functional expression of Na+/K+ ATPase and Na+/Ca2+ exchanger in mES cells during in vitro differentiation into cardiomyocytes, as well as the functional coupling between the two transporters. By measuring [Na+]i and Na+ pump current (Ip), it was shown that an ouabain-high sensitive Na+/K+ ATPase was expressed functionally in undifferentiated mES cells and these activities increased during a time course of differentiation. Using RT-PCR, the expression of mRNA for alpha1-subunit and alpha3-subunit of the Na+/K+ ATPase could be detected in both undifferentiated mES cells and derived cardiomyocytes. In contrast alpha2-subunit mRNA could be detected only in derived cardiomyocytes but not in undifferentiated mES cells. mRNA for the Na+/Ca2+ exchanger 1 isoform (NCX1) could be detected in undifferentiated mES cells and its expression levels seemed to gradually increase throughout the differentiation accompanied by increasing its Ca2+ extrusion function. At the middle stages of differentiation (after 10-day induction), more than 75% derived cardiomyocytes exhibited [Ca2+]i oscillations by blocking of Na+/K+ ATPase, suggesting the functional coupling with Na+/Ca2+ exchanger. From these results and RT-PCR analysis, we conclude that alpha2-subunit Na+/K+ ATPase mainly contributes to establish the functional coupling with NCX1 at the middle stages of differentiation of cardiomyocytes.
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Affiliation(s)
- Keishi Otsu
- Department of Cardiovascular Diseases, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
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Weiss M, Baek M, Kang W. Systems analysis of digoxin kinetics and inotropic response in the rat heart: effects of calcium and KB-R7943. Am J Physiol Heart Circ Physiol 2004; 287:H1857-67. [PMID: 15130880 DOI: 10.1152/ajpheart.01121.2003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To gain more insight into the mechanistic processes controlling the kinetics of inotropic response of digoxin in the perfused whole heart, an integrated kinetic model was developed incorporating digoxin uptake, receptor binding (Na(+)-K(+)-ATPase inhibition), and cellular events linking receptor occupation and response. The model was applied to data obtained in the single-pass Langendorff-perfused rat heart for external [Ca(2+)] of 0.5 and 1.5 mM under control conditions and in the presence of the reverse-mode Na(+)/Ca(2+) exchange inhibitor KB-R7943 (0.1 microM) in perfusate. Outflow concentration and left ventricular developed pressure data measured for three consecutive doses (15, 30, and 45 microg) in each heart were analyzed simultaneously. While disposition kinetics of digoxin was determined by interaction with a heterogeneous receptor population consisting of a high-affinity/low-capacity and a low-affinity/high- capacity binding site, response generation was >80% mediated by binding to the high-affinity receptor. Digoxin sensitivity increased at lower external [Ca(2+)] due to higher stimulus amplification. Coadministration of KB-R7943 significantly reduced the positive inotropic effect of digoxin at higher doses (30 and 45 microg) and led to a saturated and delayed receptor occupancy-response relationship in the cellular effectuation model. The results provide further evidence for the functional heterogeneity of the Na(+)-K(+)-ATPase and suggest that in the presence of KB-R7943 a reduction of the Ca(2+) influx rate via the reverse mode Na(+)/Ca(2+) exchanger might become the limiting factor in digoxin response generation.
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Affiliation(s)
- Michael Weiss
- Section of Pharmacokinetics, Dept. of Pharmacology, Martin Luther Univ. Halle-Wittenberg, D-06097 Halle, Germany.
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30
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Contreras RG, Flores-Maldonado C, Lázaro A, Shoshani L, Flores-Benitez D, Larré I, Cereijido M. Ouabain Binding to Na+,K+-ATPase Relaxes Cell Attachment and Sends a SpecificSignal (NACos) to the Nucleus. J Membr Biol 2004; 198:147-58. [PMID: 15216416 DOI: 10.1007/s00232-004-0670-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2003] [Revised: 03/01/2004] [Indexed: 10/26/2022]
Abstract
Abstract. In previous work we described a "P-->A mechanism" that transduces occupancy of the pump ( P) by ouabain into changes in phosphorylation, stimulation of mitogen-activated protein kinase (MAPK), and endocytosis of cell-cell- and cell-substrate-attaching molecules ( A), thereby causing a release of the cell from the monolayer. In the present work we try to understand the mechanism of this effect; whether, in order to trigger the P-->A mechanism, ouabain should block the pumping activity of Na(+),K(+)-ATPase as pump, or whether it would suffice that the drug occupies this enzyme as a receptor. We assay a series of drugs known to act on the pump, such as ouabain, digoxin, digitoxin, palytoxin, oligomycin, strophanthidin, neothyoside-A, proscillaridin-A, etc. We gauge their ability to block the pump by measuring the K(+) content in the cells, and their ability to detach the cells from the monolayer by determining the amount of protein remaining in the culturing well. None of the drugs tested was able to cause detachment without stopping the pump. Ouabain also enhances phosphorylation, yet pump inhibition and signal transduction do not seem to be intimately associated in a causal chain, but to occur simultaneously. To investigate the response of the site of cell attachment, we analyze the position of beta-catenin by fluorescence confocal microscopy, and find that this adherent junction-associated molecule is sent to the nucleus, where it is known to act as a transcriptional cofactor.
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Affiliation(s)
- R G Contreras
- Department of Physiology, Biophysics and Neurosciences, Av., Center for Research & Advanced Studies, Instituto Politécnico Nacional 2508, 07300, México, D.F., Mexico.
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31
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Lowe J, Araujo GMN, Pedrenho AR, Nunes-Tavares N, Ribeiro MGL, Hassón-Voloch A. Polarized distribution of Na+, K+-ATPase α-subunit isoforms in electrocyte membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1661:40-6. [PMID: 14967473 DOI: 10.1016/j.bbamem.2003.11.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2003] [Revised: 11/20/2003] [Accepted: 11/24/2003] [Indexed: 11/17/2022]
Abstract
We have previously demonstrated that Na+, K(+)-ATPase activity is present in both differentiated plasma membranes from Electrophorus electricus (L.) electrocyte. Considering that the alpha subunit is responsible for the catalytic properties of the enzyme, the aim of this work was to study the presence and localization of alpha isoforms (alpha1 and alpha2) in the electrocyte. Dose-response curves showed that non-innervated membranes present a Na+, K(+)-ATPase activity 2.6-fold more sensitive to ouabain (I50=1.0+/-0.1 microM) than the activity of innervated membranes (I50=2.6+/-0.2 microM). As depicted in [3H]ouabain binding experiments, when the [3H]ouabain-enzyme complex was incubated in a medium containing unlabeled ouabain, reversal of binding occurred differently: the bound inhibitor dissociated 32% from Na+, K(+)-ATPase in non-innervated membrane fractions within 1 h, while about 50% of the ouabain bound to the enzyme in innervated membrane fractions was released in the same time. These data are consistent with the distribution of alpha1 and alpha2 isoforms, restricted to the innervated and non-innervated membrane faces, respectively, as demonstrated by Western blotting from membrane fractions and immunohistochemical analysis of the main electric organ. The results provide direct evidence for a distinct distribution of Na+, K(+)-ATPase alpha-subunit isoforms in the differentiated membrane faces of the electrocyte, a characteristic not yet described for any polarized cell.
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Affiliation(s)
- J Lowe
- Laboratório de Físico Química-Biológica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, 21949-590, Rio de Janeiro, RJ, Brazil.
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Hoffman JF, Wickrema A, Potapova O, Milanick M, Yingst DR. Na pump isoforms in human erythroid progenitor cells and mature erythrocytes. Proc Natl Acad Sci U S A 2002; 99:14572-7. [PMID: 12388775 PMCID: PMC137924 DOI: 10.1073/pnas.222539999] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
This study is aimed at identifying the Na pump isoform composition of human erythroid precursor cells and mature human erythrocytes. We used purified and synchronously growing human erythroid progenitor cells cultured for 7-14 days. RNA was extracted from the progenitor cells on different days and analyzed by RT-PCR. The results showed that only the alpha1, alpha3, beta2, and beta3 subunit isoforms and the gamma modulator were present. Northern analysis of the erythroid progenitor cells again showed that beta2 but not beta1 or alpha2 isoforms were present. The erythroid cells display a unique beta subunit expression profile (called beta-profiling) in that they contain the message for the beta2 isoform but not beta1, whereas leukocytes and platelets are known to have the message for the beta1 but not for the beta2 isoform. This finding is taken to indicate that our preparations are essentially purely erythroid and free from white cell contamination. Western analysis of these cultured progenitor cells confirmed the presence of alpha1, alpha3, (no alpha2), beta2, beta3, and gamma together now with clear evidence that beta1 protein was also present at all stages. Western analysis of the Na pump from mature human erythrocyte ghosts, purified by ouabain column chromatography, has also shown that alpha1, alpha3, beta1, beta2, beta3, and gamma are present. Thus, the Na pump isoform composition of human erythroid precursor cells and mature erythrocytes contains the alpha1 and alpha3 isoforms of the alpha subunit, the beta1, beta2, and beta3 isoforms of the beta subunit, and the gamma modulator.
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Affiliation(s)
- Joseph F Hoffman
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA.
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