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Kinoshita PF, Orellana AM, Andreotti DZ, de Souza GA, de Mello NP, de Sá Lima L, Kawamoto EM, Scavone C. Consequences of the Lack of TNFR1 in Ouabain Response in the Hippocampus of C57BL/6J Mice. Biomedicines 2022; 10:biomedicines10112937. [PMID: 36428505 PMCID: PMC9688030 DOI: 10.3390/biomedicines10112937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022] Open
Abstract
Ouabain is a cardiac glycoside that has a protective effect against neuroinflammation at low doses through Na+/K+-ATPase signaling and that can activate tumor necrosis factor (TNF) in the brain. TNF plays an essential role in neuroinflammation and regulates glutamate receptors by acting on two different receptors (tumor necrosis factor receptor 1 [TNFR1] and TNFR2) that have distinct functions and expression. The activation of constitutively and ubiquitously expressed TNFR1 leads to the expression of pro-inflammatory cytokines. Thus, this study aimed to elucidate the effects of ouabain in a TNFR1 knockout (KO) mouse model. Interestingly, the hippocampus of TNFR1 KO mice showed a basal increase in both TNFR2 membrane expression and brain-derived neurotrophic factor (BDNF) release, suggesting a compensatory mechanism. Moreover, ouabain activated TNF-α-converting enzyme/a disintegrin and metalloprotease 17 (TACE/ADAM17), decreased N-methyl-D-aspartate (NMDA) receptor subunit 2A (NR2A) expression, and induced anxiety-like behavior in both genotype animals, independent of the presence of TNFR1. However, ouabain induced an increase in interleukin (IL)-1β in the hippocampus, a decrease in IL-6 in serum, and an increase in NMDA receptor subunit 1 (NR1) only in wild-type (WT) mice, indicating that TNFR1 or TNFR2 expression may be important for some effects of ouabain. Collectively, our results indicate a connection between ouabain signaling and TNFR1, with the effect of ouabain partially dependent on TNFR1.
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Affiliation(s)
- Paula Fernanda Kinoshita
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Ana Maria Orellana
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Diana Zukas Andreotti
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Giovanna Araujo de Souza
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Natalia Prudente de Mello
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Larissa de Sá Lima
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Elisa Mitiko Kawamoto
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Cristoforo Scavone
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Correspondence:
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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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Abdelmissih S, Sayed WM, Rashed LA, Kamel MM, Eshra MA, Attallah MI, El-Naggar RAR. The extent of involvement of ouabain, hippocampal expression of Na+/K+-ATPase, and corticosterone/melatonin receptors ratio in modifying stress-induced behavior differs according to the stressor in context. Braz J Med Biol Res 2022; 55:e11938. [PMID: 35857994 PMCID: PMC9296128 DOI: 10.1590/1414-431x2022e11938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 04/18/2022] [Indexed: 11/21/2022] Open
Abstract
The aim of this study was to assess the effect of two types of stressors,
regarding the extent of involvement of ouabain (OUA), hippocampal
sodium/potassium ATPase (NKA) expression, and the hippocampal
corticosterone receptors (CR)/melatonin receptors
(MR) expression ratio, on the behavioral and cardiovascular
responses and on the hippocampal cornu ammonis zone 3 (CA3) and dentate gyrus
(DG). Thirty adult male Wistar albino rats aged 7-8 months were exposed to
either chronic immobilization or a disturbed dark/light cycle and treated with
either ouabain or vehicle. In the immobilized group, in the absence of
hippocampal corticosterone (CORT) changes, rats were non-responsive to stress,
despite experiencing increased pulse rate, downregulated hippocampal
sodium/potassium pump, and enhanced hippocampal CR/MR
expression ratio. Prolonged darkness precipitated a reduced upright attack
posture, with elevated CORT against hippocampal MR
downregulation. Both immobilization and, to a lesser extent, prolonged darkness
stress resulted in histopathological and ultrastructural neurodegenerative
changes in the hippocampus. OUA administration did not change the behavioral
resilience in restrained rats, despite persistence of the underlying biochemical
derangements, added to decreased CORT. On the contrary, with exposure to short
photoperiods, OUA reverted the behavior towards a combative reduction of
inactivity, with unvaried CR/MR and CORT, while ameliorating
hippocampal neuro-regeneration, with co-existing NKA and
MR repressions. Therefore, the extent of OUA, hippocampal
NKA expression, and CR/MR expression, and
subsequent behavioral and cardiac responses and hippocampal histopathology,
differ according to the type of stressor, whether immobilization or prolonged
darkness.
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Affiliation(s)
- S Abdelmissih
- Department of Medical Pharmacology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - W M Sayed
- Department of Anatomy and Embryology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - L A Rashed
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - M M Kamel
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt.,Department of Basic Medical Science, Faculty of Medicine, King Salman International University, South Sinai, Egypt
| | - M A Eshra
- Department of Physiology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - M I Attallah
- Department of Medical Pharmacology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - R A-R El-Naggar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Misr University for Science and Technology, Giza, Egypt
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Kinoshita PF, Orellana AMM, Nakao VW, de Souza Port's NM, Quintas LEM, Kawamoto EM, Scavone C. The Janus face of ouabain in Na + /K + -ATPase and calcium signalling in neurons. Br J Pharmacol 2021; 179:1512-1524. [PMID: 33644859 DOI: 10.1111/bph.15419] [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: 12/09/2020] [Revised: 02/03/2021] [Accepted: 02/14/2021] [Indexed: 12/20/2022] Open
Abstract
Na+ /K+ -ATPase, a transmembrane protein essential for maintaining the electrochemical gradient across the plasma membrane, acts as a receptor for cardiotonic steroids such as ouabain. Cardiotonic steroids binding to Na+ /K+ -ATPase triggers signalling pathways or inhibits Na+ /K+ -ATPas activity in a concentration-dependent manner, resulting in a modulation of Ca2+ levels, which are essential for homeostasis in neurons. However, most of the pharmacological strategies for avoiding neuronal death do not target Na+ /K+ -ATPase activity due to its complexity and the poor understanding of the mechanisms involved in Na+ /K+ -ATPase modulation. The present review aims to discuss two points regarding the interplay between Na+ /K+ -ATPase and Ca2+ signalling in the brain. One, Na+ /K+ -ATPase impairment causing illness and neuronal death due to Ca2+ signalling and two, benefits to the brain by modulating Na+ /K+ -ATPase activity. These interactions play an essential role in neuronal cell fate determination and are relevant to find new targets for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Paula Fernanda Kinoshita
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Ana Maria Marques Orellana
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.,Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Vinicius Watanabe Nakao
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Natacha Medeiros de Souza Port's
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Luis Eduardo Menezes Quintas
- Laboratory of Biochemical and Molecular Pharmacology, Institute of Biomedical Sciences, Health Sciences Centre Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Elisa Mitiko Kawamoto
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Cristoforo Scavone
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Nunes KP, de Oliveira AA, Lima VV, Webb RC. Toll-Like Receptor 4 and Blood Pressure: Lessons From Animal Studies. Front Physiol 2019; 10:655. [PMID: 31191352 PMCID: PMC6549540 DOI: 10.3389/fphys.2019.00655] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 05/09/2019] [Indexed: 11/13/2022] Open
Affiliation(s)
- Kenia Pedrosa Nunes
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Amanda Almeida de Oliveira
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Victor Vitorino Lima
- Institute of Biological and Health Sciences, Federal University of Mato Grosso, Barra do Garças, Brazil
| | - R. Clinton Webb
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, United States
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Alpha 2 Na +,K +-ATPase silencing induces loss of inflammatory response and ouabain protection in glial cells. Sci Rep 2017; 7:4894. [PMID: 28687727 PMCID: PMC5501845 DOI: 10.1038/s41598-017-05075-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 05/24/2017] [Indexed: 12/12/2022] Open
Abstract
Ouabain (OUA) is a cardiac glycoside that binds to Na+,K+-ATPase (NKA), a conserved membrane protein that controls cell transmembrane ionic concentrations and requires ATP hydrolysis. At nM concentrations, OUA activates signaling pathways that are not related to its typical inhibitory effect on the NKA pump. Activation of these signaling pathways protects against some types of injury of the kidneys and central nervous system. There are 4 isoforms of the alpha subunit of NKA, which are differentially distributed across tissues and may have different physiological roles. Glial cells are important regulators of injury and inflammation in the brain and express the α1 and α2 NKA isoforms. This study investigated the role of α2 NKA in OUA modulation of the neuroinflammatory response induced by lipopolysaccharide (LPS) in mouse primary glial cell cultures. LPS treatment increased lactate dehydrogenase release, while OUA did not decrease cell viability and blocked LPS-induced NF-κB activation. Silencing α2 NKA prevented ERK and NF-κB activation by LPS. α2 NKA also regulates TNF-α and IL-1β levels. The data reported here indicate a significant role of α2 NKA in regulating central LPS effects, with implications in the associated neuroinflammatory processes.
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Rapôso C, Björklund U, Kalapothakis E, Biber B, Alice da Cruz-Höfling M, Hansson E. Neuropharmacological effects of Phoneutria nigriventer venom on astrocytes. Neurochem Int 2016; 96:13-23. [DOI: 10.1016/j.neuint.2016.04.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/07/2016] [Accepted: 04/14/2016] [Indexed: 11/16/2022]
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8
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Kinoshita PF, Yshii LM, Vasconcelos AR, Orellana AMM, Lima LDS, Davel APC, Rossoni LV, Kawamoto EM, Scavone C. Signaling function of Na,K-ATPase induced by ouabain against LPS as an inflammation model in hippocampus. J Neuroinflammation 2014; 11:218. [PMID: 25551197 PMCID: PMC4307894 DOI: 10.1186/s12974-014-0218-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 12/08/2014] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Ouabain (OUA) is a newly recognized hormone that is synthesized in the adrenal cortex and hypothalamus. Low doses of OUA can activate a signaling pathway by interaction with Na,K-ATPase, which is protective against a number of insults. OUA has central and peripheral anti-inflammatory effects. Lipopolysaccharide (LPS), via toll-like receptor 4 activation, is a widely used model to induce systemic inflammation. This study used a low OUA dose to evaluate its effects on inflammation induced by LPS injection in rats. METHODS Adult male Wistar rats received acute intraperitoneal (ip) OUA (1.8 μg/kg) or saline 20 minutes before LPS (200 μg/kg, ip) or saline injection. Some of the animals had their femoral artery catheterized in order to assess arterial blood pressure values before and after OUA administration. Na,K-ATPase activity, cytokine mRNA levels, apoptosis-related proteins, NF-κB activation brain-derived neurotrophic factor BDNF, corticosterone and TNF-α levels were measured. RESULTS OUA pretreatment decreased mRNA levels of the pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and IL-1β, which are activated by LPS in the hippocampus, but with no effect on serum measures of these factors. None of these OUA effects were linked to Na,K-ATPase activity. The involvement of the inflammatory transcription factor NF-κB in the OUA effect was indicated by its prevention of LPS-induced nuclear translocation of the NF-κB subunit, RELA (p65), as well as the decreased cytosol levels of the NF-κB inhibitor, IKB, in the hippocampus. OUA pretreatment reversed the LPS-induced glial fibrillary acidic protein (GFAP) activation and associated inflammation in the dentate gyrus. OUA also prevented LPS-induced increases in the hippocampal Bax/Bcl2 ratio suggesting an anti-apoptotic action in the brain. CONCLUSION Our results suggest that a low dose of OUA has an important anti-inflammatory effect in the rat hippocampus. This effect was associated with decreased GFAP induction by LPS in the dentate gyrus, a brain area linked to adult neurogenesis.
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Affiliation(s)
- Paula Fernanda Kinoshita
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil.
| | - Lidia Mitiko Yshii
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil.
| | - Andrea Rodrigues Vasconcelos
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil.
| | - Ana Maria Marques Orellana
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil.
| | - Larissa de Sá Lima
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil.
| | - Ana Paula Couto Davel
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
| | - Luciana Venturini Rossoni
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
| | - Elisa Mitiko Kawamoto
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil.
| | - Cristoforo Scavone
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil.
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Khundmiri SJ. Advances in understanding the role of cardiac glycosides in control of sodium transport in renal tubules. J Endocrinol 2014; 222:R11-24. [PMID: 24781255 DOI: 10.1530/joe-13-0613] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cardiotonic steroids have been used for the past 200 years in the treatment of congestive heart failure. As specific inhibitors of membrane-bound Na(+)/K(+) ATPase, they enhance cardiac contractility through increasing myocardial cell calcium concentration in response to the resulting increase in intracellular Na concentration. The half-minimal concentrations of cardiotonic steroids required to inhibit Na(+)/K(+) ATPase range from nanomolar to micromolar concentrations. In contrast, the circulating levels of cardiotonic steroids under physiological conditions are in the low picomolar concentration range in healthy subjects, increasing to high picomolar levels under pathophysiological conditions including chronic kidney disease and heart failure. Little is known about the physiological function of low picomolar concentrations of cardiotonic steroids. Recent studies have indicated that physiological concentrations of cardiotonic steroids acutely stimulate the activity of Na(+)/K(+) ATPase and activate an intracellular signaling pathway that regulates a variety of intracellular functions including cell growth and hypertrophy. The effects of circulating cardiotonic steroids on renal salt handling and total body sodium homeostasis are unknown. This review will focus on the role of low picomolar concentrations of cardiotonic steroids in renal Na(+)/K(+) ATPase activity, cell signaling, and blood pressure regulation.
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Affiliation(s)
- Syed Jalal Khundmiri
- Division of Nephrology and HypertensionDepartment of MedicineDepartment of Physiology and BiophysicsUniversity of Louisville, 570 S. Preston Street, Louisville, Kentucky 40202, USADivision of Nephrology and HypertensionDepartment of MedicineDepartment of Physiology and BiophysicsUniversity of Louisville, 570 S. Preston Street, Louisville, Kentucky 40202, USA
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Brain Na+/K+-ATPase α-subunit isoforms and aestivation in the African lungfish, Protopterus annectens. J Comp Physiol B 2014; 184:571-87. [PMID: 24696295 DOI: 10.1007/s00360-014-0809-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 01/16/2014] [Accepted: 01/24/2014] [Indexed: 10/25/2022]
Abstract
This study aimed to clone and sequence Na (+) / K (+)-ATPase (nka) α-subunit isoforms from, and to determine their mRNA expression levels and protein abundance in the brain of the African lungfish, Protopterus annectens during the induction, maintenance and arousal phases of aestivation in air. We obtained the full cDNA sequences of nkaα1, nkaα2 and nkaα3 from the brain of P. annectens. Phylogenetic analysis of their deduced amino acid sequences revealed that they are closer to the corresponding NKA α-subunits of tetrapods than to those of fishes. The mRNA expression of these three nkaα isoforms showed differential changes in the brain of P. annectens during the three phases of aestivation. After 12 days of aestivation, there was a significant increase in the protein abundance of Nkaα1 in the brain of P. annectens. This could be an important response to maintain cellular Na(+) and K(+) concentrations and regulate cell volume during the early maintenance phase of aestivation. On the other hand, the mRNA expression of nkaα2 decreased significantly in the brain of P. annectens after 6 months of aestivation, which could be a result of a suppression of transcriptional activities to reduce energy expenditure. The down-regulation of mRNA expression of nkaα1, nkaα2 and nkaα3 and the overall protein abundance of Nka α-subunit isoforms in the brain of P. annectens after 1 day of arousal from 6 months of aestivation were novel observations, and it could be an adaptive response to restore blood pressure and/or to prevent brain oedema.
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Ouabain activates NFκB through an NMDA signaling pathway in cultured cerebellar cells. Neuropharmacology 2013; 73:327-36. [DOI: 10.1016/j.neuropharm.2013.06.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 06/01/2013] [Accepted: 06/03/2013] [Indexed: 11/21/2022]
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Plasmalemmal Na+/Ca2+ exchanger modulates Ca2+-dependent exocytotic release of glutamate from rat cortical astrocytes. ASN Neuro 2012; 4:AN20110059. [PMID: 22268447 PMCID: PMC3284767 DOI: 10.1042/an20110059] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Astroglial excitability operates through increases in Ca2+cyt (cytosolic Ca2+), which can lead to glutamatergic gliotransmission. In parallel fluctuations in astrocytic Na+cyt (cytosolic Na+) control metabolic neuronal-glial signalling, most notably through stimulation of lactate production, which on release from astrocytes can be taken up and utilized by nearby neurons, a process referred to as lactate shuttle. Both gliotransmission and lactate shuttle play a role in modulation of synaptic transmission and plasticity. Consequently, we studied the role of the PMCA (plasma membrane Ca2+-ATPase), NCX (plasma membrane Na+/Ca2+ exchanger) and NKA (Na+/K+-ATPase) in complex and coordinated regulation of Ca2+cyt and Na+cyt in astrocytes at rest and upon mechanical stimulation. Our data support the notion that NKA and PMCA are the major Na+ and Ca2+ extruders in resting astrocytes. Surprisingly, the blockade of NKA or PMCA appeared less important during times of Ca2+ and Na+ cytosolic loads caused by mechanical stimulation. Unexpectedly, NCX in reverse mode appeared as a major contributor to overall Ca2+ and Na+ homoeostasis in astrocytes both at rest and when these glial cells were mechanically stimulated. In addition, NCX facilitated mechanically induced Ca2+-dependent exocytotic release of glutamate from astrocytes. These findings help better understanding of astrocyte-neuron bidirectional signalling at the tripartite synapse and/or microvasculature. We propose that NCX operating in reverse mode could be involved in fast and spatially localized Ca2+-dependent gliotransmission, that would operate in parallel to a slower and more widely distributed gliotransmission pathway that requires metabotropically controlled Ca2+ release from the ER (endoplasmic reticulum).
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New Insights into the Regulation of Na+,K+-ATPase by Ouabain. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 294:99-132. [DOI: 10.1016/b978-0-12-394305-7.00002-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Kawamoto EM, Lima LS, Munhoz CD, Yshii LM, Kinoshita PF, Amara FG, Pestana RRF, Orellana AMM, Cipolla-Neto J, Britto LRG, Avellar MCW, Rossoni LV, Scavone C. Influence of N-methyl-D-aspartate receptors on ouabain activation of nuclear factor-κB in the rat hippocampus. J Neurosci Res 2011; 90:213-28. [PMID: 22006678 DOI: 10.1002/jnr.22745] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 06/25/2011] [Accepted: 06/27/2011] [Indexed: 02/06/2023]
Abstract
It has been shown that ouabain (OUA) can activate the Na,K-ATPase complex and mediate intracellular signaling in the central nervous system (CNS). Inflammatory stimulus increases glutamatergic transmission, especially at N-methyl-D-aspartate (NMDA) receptors, which are usually coupled to the activation of nitric oxide synthase (NOS). Nuclear factor-κB (NF-κB) activation modulates the expression of genes involved in development, plasticity, and inflammation. The present work investigated the effects of OUA on NF-κB binding activity in rat hippocampus and the influence of this OUA-Na,K-ATPase signaling cascade in NMDA-mediated NF-κB activation. The findings presented here are the first report indicating that intrahippocampal administration of OUA, in a concentration that did not alter Na,K-ATPase or NOS activity, induced an activation of NF-κB, leading to increases in brain-derived neurotrophic factor (Bdnf), inducible NOS (iNos), tumor necrosis factor-α (Tnf-α), and B-cell leukemia/lymphoma 2 (Bcl2) mRNA levels. This response was not linked to any significant signs of neurodegeneration as showed via Fluoro-Jade B and Nissl stain. Intrahippocampal administration of NMDA induced NF-κB activation and increased NOS and α(2/3) -Na,K-ATPase activities. NMDA treatment further increased OUA-induced NF-κB activation, which was partially blocked by MK-801, an antagonist of NMDA receptor. These results suggest that OUA-induced NF-κB activation is at least in part dependent on Na,K-ATPase modulatory action of NMDA receptor in hippocampus. The interaction of these signaling pathways could be associated with biological mechanisms that may underlie the basal homeostatic state linked to the inflammatory signaling cascade in the brain.
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Affiliation(s)
- E M Kawamoto
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
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15
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Feldmann T, Shahar M, Baba A, Matsuda T, Lichtstein D, Rosen H. The Na(+)/Ca(2+)-exchanger: an essential component in the mechanism governing cardiac steroid-induced slow Ca(2+) oscillations. Cell Calcium 2011; 50:424-32. [PMID: 21930298 DOI: 10.1016/j.ceca.2011.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Revised: 07/05/2011] [Accepted: 07/07/2011] [Indexed: 02/07/2023]
Abstract
Plasma membrane (PM) Na(+), K(+)-ATPase, plays crucial roles in numerous physiological processes. Cardiac steroids (CS), such as ouabain and bufalin, specifically bind to the Na(+), K(+)-ATPase and affect ionic homeostasis, signal transduction, and endocytosed membrane traffic. CS-like compounds, synthesized in and released from the adrenal gland, are considered a new family of steroid hormones. Previous studies showed that ouabain induces slow Ca(2+) oscillations in COS-7 cells by enhancing the interactions between Na(+), K(+)-ATPase, inositol 1,4,5-trisphosphate receptor (IP(3)R) and Ankyrin B (Ank-B) to form a Ca(2+) signaling micro-domain. The activation of this micro-domain, however, is independent of InsP3 generation. Thus, the mechanism underlying the induction of these slow Ca(2+) oscillations remained largely unclear. We now show that other CS, such as bufalin, can also induce Ca(2+) oscillations. These oscillations depend on extracellular Ca(2+) concentrations [Ca(2+)](out) and are inhibited by Ni(2+). Furthermore, we found that these slow oscillations are Na(+)(out) dependent, abolished by Na(+)/Ca(2+) exchanger1 (NCX1)-specific inhibitors and markedly attenuated by NCX1 siRNA knockdown. Based on these results, a model is presented for the CS-induced slow Ca(2+) oscillations in COS-7 cells.
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Affiliation(s)
- Tomer Feldmann
- The Kuvin Center for the Study of Infectious and Tropical Diseases, Department of Microbiology and Molecular Genetics, Institute for Medical Research-Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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16
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Forshammar J, Block L, Lundborg C, Biber B, Hansson E. Naloxone and ouabain in ultralow concentrations restore Na+/K+-ATPase and cytoskeleton in lipopolysaccharide-treated astrocytes. J Biol Chem 2011; 286:31586-97. [PMID: 21757727 DOI: 10.1074/jbc.m111.247767] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Astrocytes respond to inflammatory stimuli and may be important modulators of the inflammatory response in the nervous system. This study aimed first to assess how astrocytes in primary culture behave in response to inflammatory stimuli concerning intracellular Ca(2+) responses, expression of Toll-like receptor 4 (TLR4), Na(+)/K(+)-ATPase, actin filament organization, and expression of cytokines. In a cell culture model with lipopolysaccharide (LPS), astrocyte response was assessed first in the acute phase and then after incubation with LPS for 1-48 h. The concentration curve for LPS-stimulated Ca(2+) responses was bell-shaped, and the astrocytes expressed TLR4, which detects LPS and evokes intracellular Ca(2+) transients. After a long incubation with LPS, TLR4 was up-regulated, LPS-evoked Ca(2+) transients were expressed as oscillations, Na(+)/K(+)-ATPase was down-regulated, and the actin filaments were disorganized. Interleukin-1β (IL-1β) release was increased after 24 h in LPS. A second aim was to try to restore the LPS-induced changes in astrocytes with substances that may have dose-dependent anti-inflammatory properties. Naloxone and ouabain were tested separately in ultralow or high concentrations. Both substances evoked intracellular Ca(2+) transients for all of the concentrations from 10(-15) up to 10(-4) M. Neither substance blocked the TLR4-evoked Ca(2+) responses. Naloxone and ouabain prevented the LPS-induced down-regulation of Na(+)/K(+)-ATPase and restored the actin filaments. Ouabain, in addition, reduced the IL-1β release from reactive astrocytes. Notably, ultralow concentrations (10(-12) M) of naloxone and ouabain showed these qualities. Ouabain seems to be more potent in these effects of the two tested substances.
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Affiliation(s)
- Johan Forshammar
- Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Per Dubbsgatan 14, 1tr, SE 413 45, Gothenburg, Sweden
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17
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Silveira PP, Portella AK, da Silva Benetti C, Zugno AI, da Silva Scherer EB, Mattos CB, Wyse ATS, Lucion AB, Dalmaz C. Association Between Na+,K+-ATPase Activity and the Vulnerability/Resilience to Mood Disorders induced by Early Life Experience. Neurochem Res 2011; 36:2075-82. [DOI: 10.1007/s11064-011-0531-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 06/07/2011] [Indexed: 10/18/2022]
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18
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Yatime L, Laursen M, Morth JP, Esmann M, Nissen P, Fedosova NU. Structural insights into the high affinity binding of cardiotonic steroids to the Na+,K+-ATPase. J Struct Biol 2010; 174:296-306. [PMID: 21182963 DOI: 10.1016/j.jsb.2010.12.004] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 12/13/2010] [Accepted: 12/15/2010] [Indexed: 02/08/2023]
Abstract
The Na+,K+-ATPase belongs to the P-ATPase family, whose characteristic property is the formation of a phosphorylated intermediate. The enzyme is also a defined target for cardiotonic steroids which inhibit its functional activity and initiate intracellular signaling. Here we describe the 4.6 Å resolution crystal structure of the pig kidney Na+,K+-ATPase in its phosphorylated form stabilized by high affinity binding of the cardiotonic steroid ouabain. The steroid binds to a site formed at transmembrane segments αM1-αM6, plugging the ion pathway from the extracellular side. This structure differs from the previously reported low affinity complex with potassium. Most importantly, the A domain has rotated in response to phosphorylation and αM1-2 move towards the ouabain molecule, providing for high affinity interactions and closing the ion pathway from the extracellular side. The observed re-arrangements of the Na+,K+-ATPase stabilized by cardiotonic steroids may affect protein-protein interactions within the intracellular signal transduction networks.
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Affiliation(s)
- Laure Yatime
- Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Denmark
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19
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Ionotropic receptors in neuronal-astroglial signalling: what is the role of "excitable" molecules in non-excitable cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:992-1002. [PMID: 20869992 DOI: 10.1016/j.bbamcr.2010.09.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Revised: 09/13/2010] [Accepted: 09/16/2010] [Indexed: 01/02/2023]
Abstract
Astroglial cells were long considered to serve merely as the structural and metabolic supporting cast and scenery against which the shining neurones perform their illustrious duties. Relatively recent evidence, however, indicates that astrocytes are intimately involved in many of the brain's functions. Astrocytes possess a diverse assortment of ionotropic transmitter receptors, which enable these glial cells to respond to many of the same signals that act on neurones. Ionotropic receptors mediate neurone-driven signals to astroglial cells in various brain areas including neocortex, hippocampus and cerebellum. Activation of ionotropic receptors trigger rapid signalling events in astroglia; these events, represented by local Ca(2+) or Na(+) signals provide the mechanism for fast neuronal-glial signalling at the synaptic level. Since astrocytes can detect chemical transmitters that are released from neurones and can release their own extracellular signals, gliotransmitters, they are intricately involved in homocellular and heterocellular signalling mechanisms in the nervous system. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Harrington MG, Fonteh AN, Arakaki X, Cowan RP, Ecke LE, Foster H, Hühmer AF, Biringer RG. Capillary endothelial Na(+), K(+), ATPase transporter homeostasis and a new theory for migraine pathophysiology. Headache 2010; 50:459-78. [PMID: 19845787 PMCID: PMC8020446 DOI: 10.1111/j.1526-4610.2009.01551.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Cerebrospinal fluid sodium concentration ([Na(+)](csf)) increases during migraine, but the cause of the increase is not known. OBJECTIVE Analyze biochemical pathways that influence [Na(+)](csf) to identify mechanisms that are consistent with migraine. METHOD We reviewed sodium physiology and biochemistry publications for links to migraine and pain. RESULTS Increased capillary endothelial cell (CEC) Na(+), K(+), -ATPase transporter (NKAT) activity is probably the primary cause of increased [Na(+)](csf). Physiological fluctuations of all NKAT regulators in blood, many known to be involved in migraine, are monitored by receptors on the luminal wall of brain CECs; signals are then transduced to their abluminal NKATs that alter brain extracellular sodium ([Na(+)](e)) and potassium ([K(+)](e)). CONCLUSIONS We propose a theoretical mechanism for aura and migraine when NKAT activity shifts outside normal limits: (1) CEC NKAT activity below a lower limit increases [K(+)](e), facilitates cortical spreading depression, and causes aura; (2) CEC NKAT activity above an upper limit elevates [Na(+)](e), increases neuronal excitability, and causes migraine; (3) migraine-without-aura may arise from CEC NKAT over-activity without requiring a prior decrease in activity and its consequent spreading depression; (4) migraine triggers disturb, and treatments improve, CEC NKAT homeostasis; (5) CEC NKAT-induced regulation of neural and vasomotor excitability coordinates vascular and neuronal activities, and includes occasional pathology from CEC NKAT-induced apoptosis or cerebral infarction.
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Affiliation(s)
- Michael G Harrington
- Huntington Medical Research Institutes - Molecular Neurology, Pasadena, CA 91101, USA
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21
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Liu J, Xie ZJ. The sodium pump and cardiotonic steroids-induced signal transduction protein kinases and calcium-signaling microdomain in regulation of transporter trafficking. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1237-45. [PMID: 20144708 DOI: 10.1016/j.bbadis.2010.01.013] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 01/28/2010] [Accepted: 01/30/2010] [Indexed: 12/12/2022]
Abstract
The Na/K-ATPase was discovered as an energy transducing ion pump. A major difference between the Na/K-ATPase and other P-type ATPases is its ability to bind a group of chemicals called cardiotonic steroids (CTS). The plant-derived CTS such as digoxin are valuable drugs for the management of cardiac diseases, whereas ouabain and marinobufagenin (MBG) have been identified as a new class of endogenous hormones. Recent studies have demonstrated that the endogenous CTS are important regulators of renal Na(+) excretion and blood pressure. The Na/K-ATPase is not only an ion pump, but also an important receptor that can transduce the ligand-like effect of CTS on intracellular protein kinases and Ca(2+) signaling. Significantly, these CTS-provoked signaling events are capable of reducing the surface expression of apical NHE3 (Na/H exchanger isoform 3) and basolateral Na/K-ATPase in renal proximal tubular cells. These findings suggest that endogenous CTS may play an important role in regulation of tubular Na(+) excretion under physiological conditions; conversely, a defect at either the receptor level (Na/K-ATPase) or receptor-effector coupling would reduce the ability of renal proximal tubular cells to excrete Na(+), thus culminating/resulting in salt-sensitive hypertension.
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Affiliation(s)
- Jiang Liu
- Department of Medicine, University of Toledo College of Medicine, Toledo, OH, USA
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22
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Functional and molecular interactions between aquaporins and Na,K-ATPase. Neuroscience 2009; 168:915-25. [PMID: 19962432 DOI: 10.1016/j.neuroscience.2009.11.062] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 11/18/2009] [Accepted: 11/19/2009] [Indexed: 01/11/2023]
Abstract
The water channel aquaporin 4 (AQP4) is abundantly expressed in astrocytes and provides a mechanism by which water permeability of the plasma membrane can be regulated. Astrocytes play a key role in the clearance of both potassium (K(+)) and glutamate released during neuronal activity. Emerging evidence suggests that AQP4 facilitates K(+) clearance by astrocytes and contributes to recovery of neuronal excitability. Here we report that AQP4 can assemble with its regulator metabotropic glutamate receptor 5 (mGluR5) and with Na,K-ATPase; the enzyme responsible for active K(+) transport and for establishing the electrochemical gradient across the cell plasma membrane. We have, by use of pull down assays in rat brain tissue, identified the segment in the AQP4 NH(2)-terminus containing the amino acid residues 23-32 as the site for interaction with Na,K-ATPase catalytic subunit and with mGluR5. Mutagenesis studies revealed that the AQP4 amino acids K27 and W30 are of key importance for interaction with both Na,K-ATPase and mGluR5. To confirm that interaction also occurs within intact cells, we have performed fluorescence resonance energy transfer (FRET) studies in primary astrocytes derived from rat striatum. The results indicate close proximity of wild type AQP4 and Na,K-ATPase in the plasma membrane of rat astrocytes. FRET efficiencies observed with the mutants AQP4 K27A and AQP4 W30A were significantly lower, highlighting the importance of these residues for the interaction between AQP4 and Na,K-ATPase. We conclude that AQP4/Na,K-ATPase/mGluR5 can form a macromolecular complex/transporting microdomain in astrocytes. This complex may be of functional importance for the regulation of water and K(+) homeostasis in the brain, as well as for neuron-astrocyte metabolic crosstalk.
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Central auditory dysfunction in schizophrenia as revealed by the mismatch negativity (MMN) and its magnetic equivalent MMNm: a review. Int J Neuropsychopharmacol 2009; 12:125-35. [PMID: 18771603 DOI: 10.1017/s1461145708009322] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Since the early 1990s, the auditory change-detection response, mismatch negativity (MMN) and its magnetoencephalographic (MEG) equivalent MMNm have been applied in a large number of studies on schizophrenia. These studies have enhanced our understanding of the central auditory dysfunction underlying schizophrenia. The attenuation of the MMN amplitude is a systematic and robust neurophysiological finding in these patients. The gradual attenuation of the MMN amplitude resulting from frequency change reflects the progress of the disease, particularly the impairment occurring as a function of illness duration, whereas the MMN deficiency for duration change may be more closely linked to the genetic aspect of the illness. Electroencephalographic (EEG) and magnetoencephalographic (MEG) studies, together, suggest that both the temporal and frontal cortices contributing to MMN generation are affected in schizophrenia patients. Furthermore, abnormalities in auditory perception and discrimination revealed by a deficient temporal MMN generator process might be associated with patients' positive symptoms, whereas the dampened frontal attention-switching function, suggested by the attenuated responses of the frontal MMN generator, might contribute to the negative symptoms such as social withdrawal. In addition, gradual MMN amplitude reduction, in particular that for frequency change, reflects cognitive and functional impairment occurring as a function of illness duration. Finally, as MMN can be detected even in animals such as the mouse, it might provide a useful biomarker for assessing the effects of the drugs developed to fight the cognitive and functional impairments in schizophrenia patients.
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Abstract
The Na-K-ATPase is an energy-transducing ion pump that converts the free energy of ATP into transmembrane ion gradients. It also serves as a functional receptor for cardiotonic steroids such as ouabain and digoxin. Binding of ouabain to the Na-K-ATPase can activate calcium signaling in a cell-specific manner. The exquisite calcium modulation via the Na-K-ATPase is achieved by the ability of the pump to integrate signals from numerous protein and non-protein molecules, including ion transporters, channels, protein kinases/phosphatases, as well as cellular Na+. This review focuses on the unique properties of the Na-K-ATPase and its role in the formation of different calcium-signaling microdomains.
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Affiliation(s)
- Jiang Tian
- Department of Physiology and Pharmacology, University of Toledo Health Science Campus, Toledo, Ohio, USA
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25
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Kline CF, Cunha SR, Lowe JS, Hund TJ, Mohler PJ. Revisiting ankyrin-InsP3 receptor interactions: ankyrin-B associates with the cytoplasmic N-terminus of the InsP3 receptor. J Cell Biochem 2008; 104:1244-53. [PMID: 18275062 DOI: 10.1002/jcb.21704] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Inositol 1,4,5-trisphosphate (InsP(3)) receptors are calcium-release channels found in the endoplasmic/sarcoplasmic reticulum (ER/SR) membrane of diverse cell types. InsP(3) receptors release Ca(2+) from ER/SR lumenal stores in response to InsP(3) generated from various stimuli. The complex spatial and temporal patterns of InsP(3) receptor-mediated Ca(2+) release regulate many cellular processes, ranging from gene transcription to memory. Ankyrins are adaptor proteins implicated in the targeting of ion channels and transporters to specialized membrane domains. Multiple independent studies have documented in vitro and in vivo interactions between ankyrin polypeptides and the InsP(3) receptor. Moreover, loss of ankyrin-B leads to loss of InsP(3) receptor membrane expression and stability in cardiomyocytes. Despite extensive biochemical and functional data, the validity of in vivo ankyrin-InsP(3) receptor interactions remains controversial. This controversy is based on inconsistencies between a previously identified ankyrin-binding region on the InsP(3) receptor and InsP(3) receptor topology data that demonstrate the inaccessibility of this lumenal binding site on the InsP(3) receptor to cytosolic ankyrin polypeptides. Here we use two methods to revisit the requirements on InsP(3) receptor for ankyrin binding. We demonstrate that ankyrin-B interacts with the cytoplasmic N-terminal domain of InsP(3) receptor. In summary, our findings demonstrate that the ankyrin-binding site is located on the cytoplasmic face of the InsP(3) receptor, thus validating the feasibility of in vivo ankyrin-InsP(3) receptor interactions.
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Affiliation(s)
- Crystal F Kline
- Department of Internal Medicine, Division of Cardiology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
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26
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Novel interactions of CLN3 protein link Batten disease to dysregulation of fodrin-Na+, K+ ATPase complex. Exp Cell Res 2008; 314:2895-905. [PMID: 18621045 DOI: 10.1016/j.yexcr.2008.06.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 05/22/2008] [Accepted: 06/13/2008] [Indexed: 01/15/2023]
Abstract
Juvenile neuronal ceroid lipofuscinosis (JNCL, Batten disease) is the most common progressive neurodegenerative disorder of childhood. CLN3, the transmembrane protein underlying JNCL, is proposed to participate in multiple cellular events including membrane trafficking and cytoskeletal functions. We demonstrate here that CLN3 interacts with the plasma membrane-associated cytoskeletal and endocytic fodrin and the associated Na(+), K(+) ATPase. The ion pumping activity of Na(+), K(+) ATPase was unchanged in Cln3(-/-) mouse primary neurons. However, the immunostaining pattern of fodrin appeared abnormal in JNCL fibroblasts and Cln3(-/-) mouse brains suggesting disturbances in the fodrin cytoskeleton. Furthermore, the basal subcellular distribution as well as ouabain-induced endocytosis of neuron-specific Na(+), K(+) ATPase were remarkably affected in Cln3(-/-) mouse primary neurons. These data suggest that CLN3 is involved in the regulation of plasma membrane fodrin cytoskeleton and consequently, the plasma membrane association of Na(+), K(+) ATPase. Most of the processes regulated by multifunctional fodrin and Na(+), K(+) ATPase are also affected in JNCL and Cln3-deficiency implicating that dysregulation of fodrin cytoskeleton and non-pumping functions of Na(+), K(+) ATPase may play a role in the neuronal degeneration in JNCL.
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Liu X, Špicarová Z, Rydholm S, Li J, Brismar H, Aperia A. Ankyrin B Modulates the Function of Na,K-ATPase/Inositol 1,4,5-Trisphosphate Receptor Signaling Microdomain. J Biol Chem 2008; 283:11461-8. [DOI: 10.1074/jbc.m706942200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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28
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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: 341] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [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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