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Vidović A, Dolinar K, Chibalin AV, Pirkmajer S. AMPK and glucose deprivation exert an isoform-specific effect on the expression of Na +,K +-ATPase subunits in cultured myotubes. J Muscle Res Cell Motil 2024; 45:139-154. [PMID: 38709429 DOI: 10.1007/s10974-024-09673-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024]
Abstract
In skeletal muscle, Na+,K+-ATPase (NKA), a heterodimeric (α/β) P-type ATPase, has an essential role in maintenance of Na+ and K+ homeostasis, excitability, and contractility. AMP-activated protein kinase (AMPK), an energy sensor, increases the membrane abundance and activity of NKA in L6 myotubes, but its potential role in regulation of NKA content in skeletal muscle, which determines maximum capacity for Na+ and K+ transport, has not been clearly delineated. We examined whether energy stress and/or AMPK affect expression of NKA subunits in rat L6 and primary human myotubes. Energy stress, induced by glucose deprivation, increased protein content of NKAα1 and NKAα2 in L6 myotubes, while decreasing the content of NKAα1 in human myotubes. Pharmacological AMPK activators (AICAR, A-769662, and diflunisal) modulated expression of NKA subunits, but their effects only partially mimicked those that occurred in response to glucose deprivation, indicating that AMPK does not mediate all effects of energy stress on NKA expression. Gene silencing of AMPKα1/α2 increased protein levels of NKAα1 in L6 myotubes and NKAα1 mRNA levels in human myotubes, while decreasing NKAα2 protein levels in L6 myotubes. Collectively, our results suggest a role for energy stress and AMPK in modulation of NKA expression in skeletal muscle. However, their modulatory effects were not conserved between L6 myotubes and primary human myotubes, which suggests that coupling between energy stress, AMPK, and regulation of NKA expression in vitro depends on skeletal muscle cell model.
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Affiliation(s)
- Anja Vidović
- Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
| | - Klemen Dolinar
- Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
- National Research Tomsk State University, Tomsk, Russia
| | - Sergej Pirkmajer
- Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia.
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2
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Löptien J, Vesting S, Dobler S, Mohammadi S. Evaluating the efficacy of protein quantification methods on membrane proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.02.587709. [PMID: 38617264 PMCID: PMC11014622 DOI: 10.1101/2024.04.02.587709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Protein quantification is an important tool for a wide range of biological applications. The most common broadscale methods include the Lowry, bicinchoninic acid (BCA), and Coomassie Bradford assays. Despite their wide applicability, the mechanisms of action imply that these methods may not be ideal for large transmembrane proteins due to the proteins' integration in the plasma membrane. Here, we investigate this problem by assessing the efficacy and applicability of these three common protein quantification methods on a candidate transmembrane protein - the Na,K-ATPase (NKA). We compared these methods to an ELISA, which we newly developed and describe here for the quantification of NKA. The use of a relative standard curve allows this ELISA to be easily adapted to other proteins and across the animal kingdom. Our results revealed that the three conventional methods significantly underestimate the concentration of NKA compared to the ELISA. Further, by applying the protein concentrations determined by the different methods to in vitro assays, we found that variation in the resulting data was consistently low when the assay reactions were prepared based on concentrations determined from the ELISA. Thus, when target protein concentrations vary across samples, the conventional quantification methods cannot produce reliable results in downstream applications. In contrast, the ELISA we describe here consistently provides robust results.
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3
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McKenna MJ, Renaud JM, Ørtenblad N, Overgaard K. A century of exercise physiology: effects of muscle contraction and exercise on skeletal muscle Na +,K +-ATPase, Na + and K + ions, and on plasma K + concentration-historical developments. Eur J Appl Physiol 2024; 124:681-751. [PMID: 38206444 PMCID: PMC10879387 DOI: 10.1007/s00421-023-05335-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 09/27/2023] [Indexed: 01/12/2024]
Abstract
This historical review traces key discoveries regarding K+ and Na+ ions in skeletal muscle at rest and with exercise, including contents and concentrations, Na+,K+-ATPase (NKA) and exercise effects on plasma [K+] in humans. Following initial measures in 1896 of muscle contents in various species, including humans, electrical stimulation of animal muscle showed K+ loss and gains in Na+, Cl- and H20, then subsequently bidirectional muscle K+ and Na+ fluxes. After NKA discovery in 1957, methods were developed to quantify muscle NKA activity via rates of ATP hydrolysis, Na+/K+ radioisotope fluxes, [3H]-ouabain binding and phosphatase activity. Since then, it became clear that NKA plays a central role in Na+/K+ homeostasis and that NKA content and activity are regulated by muscle contractions and numerous hormones. During intense exercise in humans, muscle intracellular [K+] falls by 21 mM (range - 13 to - 39 mM), interstitial [K+] increases to 12-13 mM, and plasma [K+] rises to 6-8 mM, whilst post-exercise plasma [K+] falls rapidly, reflecting increased muscle NKA activity. Contractions were shown to increase NKA activity in proportion to activation frequency in animal intact muscle preparations. In human muscle, [3H]-ouabain-binding content fully quantifies NKA content, whilst the method mainly detects α2 isoforms in rats. Acute or chronic exercise affects human muscle K+, NKA content, activity, isoforms and phospholemman (FXYD1). Numerous hormones, pharmacological and dietary interventions, altered acid-base or redox states, exercise training and physical inactivity modulate plasma [K+] during exercise. Finally, historical research approaches largely excluded female participants and typically used very small sample sizes.
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Affiliation(s)
- Michael J McKenna
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia.
- College of Physical Education, Southwest University, Chongqing, China.
- College of Sport Science, Zhuhai College of Science and Technology, Zhuhai, China.
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, Neuromuscular Research Center, University of Ottawa, Ottawa, ON, Canada
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Kristian Overgaard
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
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Iyer AK, Schoch KM, Verbeck A, Galasso G, Chen H, Smith S, Oldenborg A, Miller TM, Karch CM, Bonni A. Targeted ASO-mediated Atp1a2 knockdown in astrocytes reduces SOD1 aggregation and accelerates disease onset in mutant SOD1 mice. PLoS One 2023; 18:e0294731. [PMID: 38015828 PMCID: PMC10683999 DOI: 10.1371/journal.pone.0294731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 11/07/2023] [Indexed: 11/30/2023] Open
Abstract
Astrocyte-specific ion pump α2-Na+/K+-ATPase plays a critical role in the pathogenesis of amyotrophic lateral sclerosis (ALS). Here, we test the effect of Atp1a2 mRNA-specific antisense oligonucleotides (ASOs) to induce α2-Na+/K+-ATPase knockdown in the widely used ALS animal model, SOD1*G93A mice. Two ASOs led to efficient Atp1a2 knockdown and significantly reduced SOD1 aggregation in vivo. Although Atp1a2 ASO-treated mice displayed no off-target or systemic toxicity, the ASO-treated mice exhibited an accelerated disease onset and shorter lifespan than control mice. Transcriptomics studies reveal downregulation of genes involved in oxidative response, metabolic pathways, trans-synaptic signaling, and upregulation of genes involved in glutamate receptor signaling and complement activation, suggesting a potential role for these molecular pathways in de-coupling SOD1 aggregation from survival in Atp1a2 ASO-treated mice. Together, these results reveal a role for α2-Na+/K+-ATPase in SOD1 aggregation and highlight the critical effect of temporal modulation of genetically validated therapeutic targets in neurodegenerative diseases.
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Affiliation(s)
- Abhirami K. Iyer
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kathleen M. Schoch
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Anthony Verbeck
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Grant Galasso
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Hao Chen
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Sarah Smith
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Anna Oldenborg
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Timothy M. Miller
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Celeste M. Karch
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Azad Bonni
- Neuroscience and Rare Diseases, Roche Pharma Research and Early Development (pRED), Roche Innovation Centre Basel, Basel, Switzerland
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Martinez NP, Pinch M, Kandel Y, Hansen IA. Knockdown of the Sodium/Potassium ATPase Subunit Beta 2 Reduces Egg Production in the Dengue Vector, Aedes aegypti. INSECTS 2023; 14:50. [PMID: 36661978 PMCID: PMC9862990 DOI: 10.3390/insects14010050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/26/2022] [Accepted: 12/31/2022] [Indexed: 06/17/2023]
Abstract
The Na+/K+ ATPase (NKA) is present in the cellular membrane of most eukaryotic cells. It utilizes energy released by ATP hydrolysis to pump sodium ions out of the cell and potassium ions into the cell, which establishes and controls ion gradients. Functional NKA pumps consist of three subunits, alpha, beta, and FXYD. The alpha subunit serves as the catalytic subunit while the beta and FXYD subunits regulate the proper folding and localization, and ion affinity of the alpha subunit, respectively. Here we demonstrate that knockdown of NKA beta subunit 2 mRNA (nkaβ2) reduces fecundity in female Ae. aegypti. We determined the expression pattern of nkaβ2 in several adult mosquito organs using qRT-PCR. We performed RNAi-mediated knockdown of nkaβ2 and assayed for lethality, and effects on female fecundity. Tissue expression levels of nkaβ2 mRNA were highest in the ovaries with the fat body, midgut and thorax having similar expression levels, while Malpighian tubules had significantly lower expression. Survival curves recorded post dsRNA injection showed a non-significant decrease in survival of nkaβ2 dsRNA-injected mosquitoes compared to GFP dsRNA-injected mosquitoes. We observed a significant reduction in the number of eggs laid by nkaβ2 dsRNA-injected mosquitoes compared to control mosquitoes. These results, coupled with the tissue expression profile of nkaβ2, indicate that this subunit plays a role in normal female Ae. aegypti fecundity. Additional research needs to be conducted to determine the exact role played by NKAβ2 in mosquito post-blood meal nutrient sensing, transport, yolk precursor protein (YPP) synthesis and yolk deposition.
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Affiliation(s)
- Nathan P. Martinez
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
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Short-Term Mild Hypoxia Modulates Na,K-ATPase to Maintain Membrane Electrogenesis in Rat Skeletal Muscle. Int J Mol Sci 2022; 23:ijms231911869. [PMID: 36233169 PMCID: PMC9570130 DOI: 10.3390/ijms231911869] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/26/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
The Na,K-ATPase plays an important role in adaptation to hypoxia. Prolonged hypoxia results in loss of skeletal muscle mass, structure, and performance. However, hypoxic preconditioning is known to protect against a variety of functional impairments. In this study, we tested the possibility of mild hypoxia to modulate the Na,K-ATPase and to improve skeletal muscle electrogenesis. The rats were subjected to simulated high-altitude (3000 m above sea level) hypobaric hypoxia (HH) for 3 h using a hypobaric chamber. Isolated diaphragm and soleus muscles were tested. In the diaphragm muscle, HH increased the α2 Na,K-ATPase isozyme electrogenic activity and stably hyperpolarized the extrajunctional membrane for 24 h. These changes were accompanied by a steady increase in the production of thiobarbituric acid reactive substances as well as a decrease in the serum level of endogenous ouabain, a specific ligand of the Na,K-ATPase. HH also increased the α2 Na,K-ATPase membrane abundance without changing its total protein content; the plasma membrane lipid-ordered phase did not change. In the soleus muscle, HH protected against disuse (hindlimb suspension) induced sarcolemmal depolarization. Considering that the Na,K-ATPase is critical for maintaining skeletal muscle electrogenesis and performance, these findings may have implications for countermeasures in disuse-induced pathology and hypoxic therapy.
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Chronic Ouabain Prevents Radiation-Induced Reduction in the α2 Na,K-ATPase Function in the Rat Diaphragm Muscle. Int J Mol Sci 2022; 23:ijms231810921. [PMID: 36142836 PMCID: PMC9505176 DOI: 10.3390/ijms231810921] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/11/2022] [Accepted: 09/15/2022] [Indexed: 11/29/2022] Open
Abstract
The damaging effect of ionizing radiation (IR) on skeletal muscle Na,K-ATPase is an open field of research. Considering a therapeutic potential of ouabain, a specific ligand of the Na,K-ATPase, we tested its ability to protect against the IR-induced disturbances of Na,K-ATPase function in rat diaphragm muscle that co-expresses the α1 and α2 isozymes of this protein. Male Wistar rats (n = 26) were subjected to 6-day injections of vehicle (0.9% NaCl) or ouabain (1 µg/kg/day). On the fourth day of injections, rats were exposed to one-time total-body X-ray irradiation (10 Gy), or a sham irradiation. The isolated muscles were studied 72 h post-irradiation. IR decreased the electrogenic contribution of the α2 Na,K-ATPase without affecting its protein content, thereby causing sarcolemma depolarization. IR increased serum concentrations of ouabain, IL-6, and corticosterone, decreased lipid peroxidation, and changed cellular redox status. Chronic ouabain administration prevented IR-induced depolarization and loss of the α2 Na,K-ATPase electrogenic contribution without changing its protein content. This was accompanied with an elevation of ouabain concentration in circulation and with the lack of IR-induced suppression of lipid peroxidation. Given the crucial role of Na,K-ATPase in skeletal muscle performance, these findings may have therapeutic implications as countermeasures for IR-induced muscle pathology.
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8
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Skogestad J, Aronsen JM. Regulation of Cardiac Contractility by the Alpha 2 Subunit of the Na+/K+-ATPase. Front Physiol 2022; 13:827334. [PMID: 35812308 PMCID: PMC9258780 DOI: 10.3389/fphys.2022.827334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/16/2022] [Indexed: 11/14/2022] Open
Abstract
Cytosolic Na + concentrations regulate cardiac excitation-contraction coupling and contractility. Inhibition of the Na+/K+-ATPase (NKA) activity increases cardiac contractility by increasing cytosolic Ca2+ levels, as increased cytosolic Na+ levels are coupled to less Ca2+ extrusion and/or increased Ca2+ influx from the Na+/Ca2+-exchanger. NKA consists of one α subunit and one β subunit, with α1 and α2 being the main α isoforms in cardiomyocytes. Substantial evidence suggests that NKAα2 is the primary regulator of cardiac contractility despite being outnumbered by NKAα1 in cardiomyocytes. This review will mainly focus on differential regulation and subcellular localization of the NKAα1 and NKAα2 isoforms, and their relation to the proposed concept of subcellular gradients of Na+ in cardiomyocytes. We will also discuss the potential roles of NKAα2 in mediating cardiac hypertrophy and ventricular arrhythmias.
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Affiliation(s)
- Jonas Skogestad
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Jan Magnus Aronsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
- *Correspondence: Jan Magnus Aronsen,
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9
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Kravtsova VV, Krivoi II. Molecular and Functional Heterogeneity of Na,K-ATPase in the Skeletal Muscle. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021040086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Mohammadi S, Yang L, Harpak A, Herrera-Álvarez S, Del Pilar Rodríguez-Ordoñez M, Peng J, Zhang K, Storz JF, Dobler S, Crawford AJ, Andolfatto P. Concerted evolution reveals co-adapted amino acid substitutions in Na +K +-ATPase of frogs that prey on toxic toads. Curr Biol 2021; 31:2530-2538.e10. [PMID: 33887183 DOI: 10.1016/j.cub.2021.03.089] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/12/2021] [Accepted: 03/26/2021] [Indexed: 11/18/2022]
Abstract
Although gene duplication is an important source of evolutionary innovation, the functional divergence of duplicates can be opposed by ongoing gene conversion between them. Here, we report on the evolution of a tandem duplication of Na+,K+-ATPase subunit α1 (ATP1A1) shared by frogs in the genus Leptodactylus, a group of species that feeds on toxic toads. One ATP1A1 paralog evolved resistance to toad toxins although the other retained ancestral susceptibility. Within species, frequent non-allelic gene conversion homogenized most of the sequence between the two copies but was counteracted by strong selection on 12 amino acid substitutions that distinguish the two paralogs. Protein-engineering experiments show that two of these substitutions substantially increase toxin resistance, whereas the additional 10 mitigate their deleterious effects on ATPase activity. Our results reveal how examination of neo-functionalized gene duplicate evolution can help pinpoint key functional substitutions and interactions with the genetic backgrounds on which they arise.
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Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Lu Yang
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Arbel Harpak
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | | | | | - Julie Peng
- Lewis-Sigler Institute, Princeton University, Princeton, NJ, USA
| | - Karen Zhang
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Susanne Dobler
- Molecular Evolutionary Biology, Zoological Institute, Universität Hamburg, Hamburg, Germany
| | - Andrew J Crawford
- Department of Biological Sciences, Universidad de los Andes, Bogotá 111711, Colombia.
| | - Peter Andolfatto
- Department of Biological Sciences, Columbia University, New York, NY, USA.
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Chronic Ouabain Prevents Na,K-ATPase Dysfunction and Targets AMPK and IL-6 in Disused Rat Soleus Muscle. Int J Mol Sci 2021; 22:ijms22083920. [PMID: 33920198 PMCID: PMC8069997 DOI: 10.3390/ijms22083920] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/02/2021] [Accepted: 04/08/2021] [Indexed: 12/20/2022] Open
Abstract
Sustained sarcolemma depolarization due to loss of the Na,K-ATPase function is characteristic for skeletal muscle motor dysfunction. Ouabain, a specific ligand of the Na,K-ATPase, has a circulating endogenous analogue. We hypothesized that the Na,K-ATPase targeted by the elevated level of circulating ouabain modulates skeletal muscle electrogenesis and prevents its disuse-induced disturbances. Isolated soleus muscles from rats intraperitoneally injected with ouabain alone or subsequently exposed to muscle disuse by 6-h hindlimb suspension (HS) were studied. Conventional electrophysiology, Western blotting, and confocal microscopy with cytochemistry were used. Acutely applied 10 nM ouabain hyperpolarized the membrane. However, a single injection of ouabain (1 µg/kg) prior HS was unable to prevent the HS-induced membrane depolarization. Chronic administration of ouabain for four days did not change the α1 and α2 Na,K-ATPase protein content, however it partially prevented the HS-induced loss of the Na,K-ATPase electrogenic activity and sarcolemma depolarization. These changes were associated with increased phosphorylation levels of AMP-activated protein kinase (AMPK), its substrate acetyl-CoA carboxylase and p70 protein, accompanied with increased mRNA expression of interleikin-6 (IL-6) and IL-6 receptor. Considering the role of AMPK in regulation of the Na,K-ATPase, we suggest an IL-6/AMPK contribution to prevent the effects of chronic ouabain under skeletal muscle disuse.
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Jan V, Miš K, Nikolic N, Dolinar K, Petrič M, Bone A, Thoresen GH, Rustan AC, Marš T, Chibalin AV, Pirkmajer S. Effect of differentiation, de novo innervation, and electrical pulse stimulation on mRNA and protein expression of Na+,K+-ATPase, FXYD1, and FXYD5 in cultured human skeletal muscle cells. PLoS One 2021; 16:e0247377. [PMID: 33635930 PMCID: PMC7909653 DOI: 10.1371/journal.pone.0247377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 02/05/2021] [Indexed: 12/18/2022] Open
Abstract
Denervation reduces the abundance of Na+,K+-ATPase (NKA) in skeletal muscle, while reinnervation increases it. Primary human skeletal muscle cells, the most widely used model to study human skeletal muscle in vitro, are usually cultured as myoblasts or myotubes without neurons and typically do not contract spontaneously, which might affect their ability to express and regulate NKA. We determined how differentiation, de novo innervation, and electrical pulse stimulation affect expression of NKA (α and β) subunits and NKA regulators FXYD1 (phospholemman) and FXYD5 (dysadherin). Differentiation of myoblasts into myotubes under low serum conditions increased expression of myogenic markers CD56 (NCAM1), desmin, myosin heavy chains, dihydropyridine receptor subunit α1S, and SERCA2 as well as NKAα2 and FXYD1, while it decreased expression of FXYD5 mRNA. Myotubes, which were innervated de novo by motor neurons in co-culture with the embryonic rat spinal cord explants, started to contract spontaneously within 7–10 days. A short-term co-culture (10–11 days) promoted mRNA expression of myokines, such as IL-6, IL-7, IL-8, and IL-15, but did not affect mRNA expression of NKA, FXYDs, or myokines, such as musclin, cathepsin B, meteorin-like protein, or SPARC. A long-term co-culture (21 days) increased the protein abundance of NKAα1, NKAα2, FXYD1, and phospho-FXYD1Ser68 without attendant changes in mRNA levels. Suppression of neuromuscular transmission with α-bungarotoxin or tubocurarine for 24 h did not alter NKA or FXYD mRNA expression. Electrical pulse stimulation (48 h) of non-innervated myotubes promoted mRNA expression of NKAβ2, NKAβ3, FXYD1, and FXYD5. In conclusion, low serum concentration promotes NKAα2 and FXYD1 expression, while de novo innervation is not essential for upregulation of NKAα2 and FXYD1 mRNA in cultured myotubes. Finally, although innervation and EPS both stimulate contractions of myotubes, they exert distinct effects on the expression of NKA and FXYDs.
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Affiliation(s)
- Vid Jan
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Katarina Miš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Natasa Nikolic
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Klemen Dolinar
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Metka Petrič
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Andraž Bone
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - G. Hege Thoresen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Arild C. Rustan
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Tomaž Marš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Alexander V. Chibalin
- National Research Tomsk State University, Tomsk, Russia
- Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- * E-mail:
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13
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The role of AMPK in regulation of Na +,K +-ATPase in skeletal muscle: does the gauge always plug the sink? J Muscle Res Cell Motil 2021; 42:77-97. [PMID: 33398789 DOI: 10.1007/s10974-020-09594-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/14/2020] [Indexed: 12/14/2022]
Abstract
AMP-activated protein kinase (AMPK) is a cellular energy gauge and a major regulator of cellular energy homeostasis. Once activated, AMPK stimulates nutrient uptake and the ATP-producing catabolic pathways, while it suppresses the ATP-consuming anabolic pathways, thus helping to maintain the cellular energy balance under energy-deprived conditions. As much as ~ 20-25% of the whole-body ATP consumption occurs due to a reaction catalysed by Na+,K+-ATPase (NKA). Being the single most important sink of energy, NKA might seem to be an essential target of the AMPK-mediated energy saving measures, yet NKA is vital for maintenance of transmembrane Na+ and K+ gradients, water homeostasis, cellular excitability, and the Na+-coupled transport of nutrients and ions. Consistent with the model that AMPK regulates ATP consumption by NKA, activation of AMPK in the lung alveolar cells stimulates endocytosis of NKA, thus suppressing the transepithelial ion transport and the absorption of the alveolar fluid. In skeletal muscles, contractions activate NKA, which opposes a rundown of transmembrane ion gradients, as well as AMPK, which plays an important role in adaptations to exercise. Inhibition of NKA in contracting skeletal muscle accentuates perturbations in ion concentrations and accelerates development of fatigue. However, different models suggest that AMPK does not inhibit or even stimulates NKA in skeletal muscle, which appears to contradict the idea that AMPK maintains the cellular energy balance by always suppressing ATP-consuming processes. In this short review, we examine the role of AMPK in regulation of NKA in skeletal muscle and discuss the apparent paradox of AMPK-stimulated ATP consumption.
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14
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Smith SE, Chen X, Brier LM, Bumstead JR, Rensing NR, Ringel AE, Shin H, Oldenborg A, Crowley JR, Bice AR, Dikranian K, Ippolito JE, Haigis MC, Papouin T, Zhao G, Wong M, Culver JP, Bonni A. Astrocyte deletion of α2-Na/K ATPase triggers episodic motor paralysis in mice via a metabolic pathway. Nat Commun 2020; 11:6164. [PMID: 33268780 PMCID: PMC7710756 DOI: 10.1038/s41467-020-19915-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 11/06/2020] [Indexed: 12/12/2022] Open
Abstract
Familial hemiplegic migraine is an episodic neurological disorder characterized by transient sensory and motor symptoms and signs. Mutations of the ion pump α2-Na/K ATPase cause familial hemiplegic migraine, but the mechanisms by which α2-Na/K ATPase mutations lead to the migraine phenotype remain incompletely understood. Here, we show that mice in which α2-Na/K ATPase is conditionally deleted in astrocytes display episodic paralysis. Functional neuroimaging reveals that conditional α2-Na/K ATPase knockout triggers spontaneous cortical spreading depression events that are associated with EEG low voltage activity events, which correlate with transient motor impairment in these mice. Transcriptomic and metabolomic analyses show that α2-Na/K ATPase loss alters metabolic gene expression with consequent serine and glycine elevation in the brain. A serine- and glycine-free diet rescues the transient motor impairment in conditional α2-Na/K ATPase knockout mice. Together, our findings define a metabolic mechanism regulated by astrocytic α2-Na/K ATPase that triggers episodic motor paralysis in mice.
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Affiliation(s)
- Sarah E Smith
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
- MD-PhD Program, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Xiaoying Chen
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Lindsey M Brier
- MD-PhD Program, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jonathan R Bumstead
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63105, USA
| | - Nicholas R Rensing
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Alison E Ringel
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Haewon Shin
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Anna Oldenborg
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jan R Crowley
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Annie R Bice
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Krikor Dikranian
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Joseph E Ippolito
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Marcia C Haigis
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Thomas Papouin
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Guoyan Zhao
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Michael Wong
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Joseph P Culver
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63105, USA
- Department of Physics, Washington University in St. Louis, St. Louis, MO, 63105, USA
| | - Azad Bonni
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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15
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Pirkmajer S, Bezjak K, Matkovič U, Dolinar K, Jiang LQ, Miš K, Gros K, Milovanova K, Pirkmajer KP, Marš T, Kapilevich L, Chibalin AV. Ouabain Suppresses IL-6/STAT3 Signaling and Promotes Cytokine Secretion in Cultured Skeletal Muscle Cells. Front Physiol 2020; 11:566584. [PMID: 33101052 PMCID: PMC7544989 DOI: 10.3389/fphys.2020.566584] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/25/2020] [Indexed: 12/16/2022] Open
Abstract
The cardiotonic steroids (CTS), such as ouabain and marinobufagenin, are thought to be adrenocortical hormones secreted during exercise and the stress response. The catalytic α-subunit of Na,K-ATPase (NKA) is a CTS receptor, whose largest pool is located in skeletal muscles, indicating that muscles are a major target for CTS. Skeletal muscles contribute to adaptations to exercise by secreting interleukin-6 (IL-6) and plethora of other cytokines, which exert paracrine and endocrine effects in muscles and non-muscle tissues. Here, we determined whether ouabain, a prototypical CTS, modulates IL-6 signaling and secretion in the cultured human skeletal muscle cells. Ouabain (2.5–50 nM) suppressed the abundance of STAT3, a key transcription factor downstream of the IL-6 receptor, as well as its basal and IL-6-stimulated phosphorylation. Conversely, ouabain (50 nM) increased the phosphorylation of ERK1/2, Akt, p70S6K, and S6 ribosomal protein, indicating activation of the ERK1/2 and the Akt-mTOR pathways. Proteasome inhibitor MG-132 blocked the ouabain-induced suppression of the total STAT3, but did not prevent the dephosphorylation of STAT3. Ouabain (50 nM) suppressed hypoxia-inducible factor-1α (HIF-1α), a modulator of STAT3 signaling, but gene silencing of HIF-1α and/or its partner protein HIF-1β did not mimic effects of ouabain on the phosphorylation of STAT3. Ouabain (50 nM) failed to suppress the phosphorylation of STAT3 and HIF-1α in rat L6 skeletal muscle cells, which express the ouabain-resistant α1-subunit of NKA. We also found that ouabain (100 nM) promoted the secretion of IL-6, IL-8, GM-CSF, and TNF-α from the skeletal muscle cells of healthy subjects, and the secretion of GM-CSF from cells of subjects with the type 2 diabetes. Marinobufagenin (10 nM), another important CTS, did not alter the secretion of these cytokines. In conclusion, our study shows that ouabain suppresses the IL-6 signaling via STAT3, but promotes the secretion of IL-6 and other cytokines, which might represent a negative feedback in the IL-6/STAT3 pathway. Collectively, our results implicate a role for CTS and NKA in regulation of the IL-6 signaling and secretion in skeletal muscle.
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Affiliation(s)
- Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Katja Bezjak
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Urška Matkovič
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Klemen Dolinar
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Lake Q Jiang
- Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Katarina Miš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Katarina Gros
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Kseniya Milovanova
- Department of Sports and Health Tourism, Sports Physiology and Medicine, National Research Tomsk State University, Tomsk, Russia
| | - Katja Perdan Pirkmajer
- Department of Rheumatology, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Department of Internal Medicine, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tomaž Marš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Leonid Kapilevich
- Department of Sports and Health Tourism, Sports Physiology and Medicine, National Research Tomsk State University, Tomsk, Russia.,Central Scientific Laboratory, Siberian State Medical University, Tomsk, Russia
| | - Alexander V Chibalin
- Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
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16
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Melone M, Ciriachi C, Pietrobon D, Conti F. Heterogeneity of Astrocytic and Neuronal GLT-1 at Cortical Excitatory Synapses, as Revealed by its Colocalization With Na+/K+-ATPase α Isoforms. Cereb Cortex 2020; 29:3331-3350. [PMID: 30260367 DOI: 10.1093/cercor/bhy203] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 12/29/2022] Open
Abstract
GLT-1, the major glutamate transporter, is expressed at perisynaptic astrocytic processes (PAP) and axon terminals (AxT). GLT-1 is coupled to Na+/K+-ATPase (NKA) α1-3 isoforms, whose subcellular distribution and spatial organization in relationship to GLT-1 are largely unknown. Using several microscopy techniques, we showed that at excitatory synapses α1 and α3 are exclusively neuronal (mainly in dendrites and in some AxT), while α2 is predominantly astrocytic. GLT-1 displayed a differential colocalization with α1-3. GLT-1/α2 and GLT-1/α3 colocalization was higher in GLT-1 positive puncta partially (for GLT-1/α2) or almost totally (for GLT-1/α3) overlapping with VGLUT1 positive terminals than in nonoverlapping ones. GLT-1 colocalized with α2 at PAP, and with α1 and α3 at AxT. GLT-1 and α2 gold particles were ∼1.5-2 times closer than GLT-1/α1 and GLT-1/α3 particles. GLT-1/α2 complexes (edge to edge interdistance of gold particles ≤50 nm) concentrated at the perisynaptic region of PAP membranes, whereas neuronal GLT-1/α1 and GLT-1/α3 complexes were fewer and more uniformly distributed in AxT. These data unveil different composition of GLT-1 and α subunits complexes in the glial and neuronal domains of excitatory synapses. The spatial organization of GLT-1/α1-3 complexes suggests that GLT-1/NKA interaction is more efficient in astrocytes than in neurons, further supporting the dominant role of astrocytic GLT-1 in glutamate homeostasis.
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Affiliation(s)
- Marcello Melone
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy.,Center for Neurobiology of Aging, IRCCS INRCA, Ancona, Italy
| | - Chiara Ciriachi
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Daniela Pietrobon
- Department of Biomedical Sciences, University of Padova, and CNR Institute of Neuroscience, Padova, Italy
| | - Fiorenzo Conti
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy.,Center for Neurobiology of Aging, IRCCS INRCA, Ancona, Italy.,Foundation for Molecular Medicine, Università Politecnica delle Marche, Ancona, Italy
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17
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Else PL. Postnatal development in the rat: Changes in Na+ flux, sodium pump molecular activity and membrane lipid composition. Mech Dev 2020; 162:103610. [DOI: 10.1016/j.mod.2020.103610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 03/11/2020] [Accepted: 04/24/2020] [Indexed: 11/25/2022]
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18
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Kravtsova VV, Bouzinova EV, Chibalin AV, Matchkov VV, Krivoi II. Isoform-specific Na,K-ATPase and membrane cholesterol remodeling in motor endplates in distinct mouse models of myodystrophy. Am J Physiol Cell Physiol 2020; 318:C1030-C1041. [PMID: 32293933 DOI: 10.1152/ajpcell.00453.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Na,K-ATPase is a membrane transporter that is critically important for skeletal muscle function. Mdx and Bla/J mice are the experimental models of Duchenne muscular dystrophy and dysferlinopathy that are known to differ in the molecular mechanism of the pathology. This study examines the function of α1- and α2-Na,K-ATPase isozymes in respiratory diaphragm and postural soleus muscles from mdx and Bla/J mice compared with control С57Bl/6 mice. In diaphragm muscles, the motor endplate structure was severely disturbed (manifested by defragmentation) in mdx mice only. The endplate membrane of both Bla/J and mdx mice was depolarized due to specific loss of the α2-Na,K-ATPase electrogenic activity and its decreased membrane abundance. Total FXYD1 subunit (modulates Na,K-ATPase activity) abundance was decreased in both mouse models. However, the α2-Na,K-ATPase protein content as well as mRNA expression were specifically and significantly reduced only in mdx mice. The endplate membrane cholesterol redistribution was most pronounced in mdx mice. Soleus muscles from Bla/J and mdx mice demonstrated reduction of the α2-Na,K-ATPase membrane abundance and mRNA expression similar to the diaphragm muscles. In contrast to diaphragm, the α2-Na,K-ATPase protein content was altered in both Bla/J and mdx mice; membrane cholesterol re-distribution was not observed. Thus, the α2-Na,K-ATPase is altered in both Bla/J and mdx mouse models of chronic muscle pathology. However, despite some similarities, the α2-Na,K-ATPase and cholesterol abnormalities are more pronounced in mdx mice.
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Affiliation(s)
- Violetta V Kravtsova
- Department of General Physiology, St. Petersburg State University, St. Petersburg, Russia
| | | | | | | | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University, St. Petersburg, Russia
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19
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Reiffurth C, Alam M, Zahedi-Khorasani M, Major S, Dreier JP. Na +/K +-ATPase α isoform deficiency results in distinct spreading depolarization phenotypes. J Cereb Blood Flow Metab 2020; 40:622-638. [PMID: 30819023 PMCID: PMC7025397 DOI: 10.1177/0271678x19833757] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Compromised Na+/K+-ATPase function is associated with the occurrence of spreading depolarization (SD). Mutations in ATP1A2, the gene encoding the α2 isoform of the Na+/K+-ATPase, were identified in patients with familial hemiplegic migraine type 2 (FHM2), a Mendelian model disease for SD. This suggests a distinct role for the α2 isoform in modulating SD susceptibility and raises questions about underlying mechanisms including the roles of other Na+/K+-ATPase α isoforms. Here, we investigated the effects of genetic ablation and pharmacological inhibition of α1, α2, and α3 on SD using heterozygous knock-out mice. We found that only α2 heterozygous mice displayed higher SD susceptibility when challenged with prolonged extracellular high potassium concentration ([K+]o), a pronounced post SD oligemia and higher SD speed in-vivo. By contrast, under physiological [K+]o, α2 heterozygous mice showed similar SD susceptibility compared to wild-type littermates. Deficiency of α3 resulted in increased resistance against electrically induced SD in-vivo, whereas α1 deficiency did not affect SD. The results support important roles of the α2 isoform in SD. Moreover, they suggest that specific experimental conditions can be necessary to reveal an inherent SD phenotype by driving a (meta-) stable system into decompensation, reminiscent of the episodic nature of SDs in various diseases.
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Affiliation(s)
- Clemens Reiffurth
- Department of Experimental Neurology, Charité-University Medicine Berlin, Berlin, Germany.,Center for Stroke Research, Charité-University Medicine Berlin, Berlin, Germany
| | - Mesbah Alam
- Department of Neurosurgery, Hannover Medical School, Hannover, Germany
| | - Mahdi Zahedi-Khorasani
- Research Center and Department of Physiology, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Sebastian Major
- Department of Experimental Neurology, Charité-University Medicine Berlin, Berlin, Germany.,Center for Stroke Research, Charité-University Medicine Berlin, Berlin, Germany.,Department of Neurology, Charité-University Medicine Berlin, Berlin, Germany
| | - Jens P Dreier
- Department of Experimental Neurology, Charité-University Medicine Berlin, Berlin, Germany.,Center for Stroke Research, Charité-University Medicine Berlin, Berlin, Germany.,Department of Neurology, Charité-University Medicine Berlin, Berlin, Germany.,Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Berlin, Germany
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20
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Tapella L, Soda T, Mapelli L, Bortolotto V, Bondi H, Ruffinatti FA, Dematteis G, Stevano A, Dionisi M, Ummarino S, Di Ruscio A, Distasi C, Grilli M, Genazzani AA, D'Angelo E, Moccia F, Lim D. Deletion of calcineurin from GFAP‐expressing astrocytes impairs excitability of cerebellar and hippocampal neurons through astroglial Na+/K+ATPase. Glia 2019; 68:543-560. [DOI: 10.1002/glia.23737] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Laura Tapella
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Teresa Soda
- Department of Brain and Behavioral SciencesUniversity of Pavia Pavia Italy
| | - Lisa Mapelli
- Department of Brain and Behavioral SciencesUniversity of Pavia Pavia Italy
| | - Valeria Bortolotto
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Heather Bondi
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Federico A. Ruffinatti
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Giulia Dematteis
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Alessio Stevano
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Marianna Dionisi
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Simone Ummarino
- Center of Life ScienceMedical School Initiative for RNA Medicine, Harvard Medical School Boston Massachusetts
- Department of Translational MedicineUniversità del Piemonte Orientale Novara Italy
| | - Annalisa Di Ruscio
- Center of Life ScienceMedical School Initiative for RNA Medicine, Harvard Medical School Boston Massachusetts
- Department of Translational MedicineUniversità del Piemonte Orientale Novara Italy
| | - Carla Distasi
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Mariagrazia Grilli
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Armando A. Genazzani
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
| | - Egidio D'Angelo
- Department of Brain and Behavioral SciencesUniversity of Pavia Pavia Italy
- IRCCS Mondino Foundation Pavia Italy
| | - Francesco Moccia
- Department of Biology and Biotechnology “Lazzaro Spallanzani”University of Pavia Pavia Italy
| | - Dmitry Lim
- Department of Pharmaceutical SciencesUniversità del Piemonte Orientale “Amedeo Avogadro” Novara Italy
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21
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Sampedro Castañeda M, Zanoteli E, Scalco RS, Scaramuzzi V, Marques Caldas V, Conti Reed U, da Silva AMS, O'Callaghan B, Phadke R, Bugiardini E, Sud R, McCall S, Hanna MG, Poulsen H, Männikkö R, Matthews E. A novel ATP1A2 mutation in a patient with hypokalaemic periodic paralysis and CNS symptoms. Brain 2019; 141:3308-3318. [PMID: 30423015 PMCID: PMC6262219 DOI: 10.1093/brain/awy283] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/25/2018] [Indexed: 01/26/2023] Open
Abstract
Hypokalaemic periodic paralysis is a rare genetic neuromuscular disease characterized by episodes of skeletal muscle paralysis associated with low serum potassium. Muscle fibre inexcitability during attacks of paralysis is due to an aberrant depolarizing leak current through mutant voltage sensing domains of either the sarcolemmal voltage-gated calcium or sodium channel. We report a child with hypokalaemic periodic paralysis and CNS involvement, including seizures, but without mutations in the known periodic paralysis genes. We identified a novel heterozygous de novo missense mutation in the ATP1A2 gene encoding the α2 subunit of the Na+/K+-ATPase that is abundantly expressed in skeletal muscle and in brain astrocytes. Pump activity is crucial for Na+ and K+ homeostasis following sustained muscle or neuronal activity and its dysfunction is linked to the CNS disorders hemiplegic migraine and alternating hemiplegia of childhood, but muscle dysfunction has not been reported. Electrophysiological measurements of mutant pump activity in Xenopus oocytes revealed lower turnover rates in physiological extracellular K+ and an anomalous inward leak current in hypokalaemic conditions, predicted to lead to muscle depolarization. Our data provide important evidence supporting a leak current as the major pathomechanism underlying hypokalaemic periodic paralysis and indicate ATP1A2 as a new hypokalaemic periodic paralysis gene.
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Affiliation(s)
- Marisol Sampedro Castañeda
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Edmar Zanoteli
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Renata S Scalco
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Vinicius Scaramuzzi
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Vitor Marques Caldas
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Umbertina Conti Reed
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | | | - Benjamin O'Callaghan
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Rahul Phadke
- Division of Neuropathology, UCL Institute of Neurology, London, UK
| | - Enrico Bugiardini
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Richa Sud
- Neurogenetics Unit, UCL Institute of Neurology, Queen Square, London, UK
| | - Samuel McCall
- Neurogenetics Unit, UCL Institute of Neurology, Queen Square, London, UK
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Hanne Poulsen
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Aarhus University, DK-8000 Aarhus, Denmark
| | - Roope Männikkö
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
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22
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Xu Y, Halievski K, Katsuno M, Adachi H, Sobue G, Breedlove SM, Jordan CL. Pre-clinical symptoms of SBMA may not be androgen-dependent: implications from two SBMA mouse models. Hum Mol Genet 2019; 27:2425-2442. [PMID: 29897452 DOI: 10.1093/hmg/ddy142] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 04/16/2018] [Indexed: 12/31/2022] Open
Abstract
A distinguishing aspect of spinal and bulbar muscular atrophy (SBMA) is its androgen-dependence, possibly explaining why only males are clinically affected. This disease, which impairs neuromuscular function, is linked to a polyglutamine expansion mutation in the androgen receptor (AR). In mouse models of SBMA, motor dysfunction is associated with pronounced defects in neuromuscular transmission, including defects in evoked transmitter release (quantal content, QC) and fiber membrane excitability (based on the resting membrane potential, RMP). However, whether such defects are androgen-dependent is unknown. Thus, we recorded synaptic potentials intracellularly from adult muscle fibers of transgenic (Tg) AR97Q male mice castrated pre-symptomatically. Although castration largely protects both QC and the RMP of fibers, correlating with the protective effect of castration on motor function, significant deficits in QC and RMP remained. Surprisingly, comparable defects in QC and RMP were also observed in pre-symptomatic AR97Q males, indicating that such defects emerge early and are pre-clinical. Exposing asymptomatic Tg females to androgens also induces both motor dysfunction and comparable defects in QC and RMP. Notably, asymptomatic Tg females also showed significant deficits in QC and RMP, albeit less severe, supporting their pre-clinical nature, but also raising questions about the androgen-dependence of pre-clinical symptoms. In summary, current evidence indicates that disease progression depends on androgens, but early pathogenic events may be triggered by the mutant AR allele independent of androgens. Such early, androgen-independent disease mechanisms may also be relevant to females carrying the SBMA allele.
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Affiliation(s)
- Youfen Xu
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | | | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - Hiroaki Adachi
- Department of Neurology, University of Occupational and Environment Health School of Medicine, Yahatanishi-ku, Kitakyushu Fukuoka, Japan
| | - Gen Sobue
- Department of Neurology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - S Marc Breedlove
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Cynthia L Jordan
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
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23
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Hormonal regulation of Na +-K +-ATPase from the evolutionary perspective. CURRENT TOPICS IN MEMBRANES 2019; 83:315-351. [PMID: 31196608 DOI: 10.1016/bs.ctm.2019.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Na+-K+-ATPase, an α/β heterodimer, is an ancient enzyme that maintains Na+ and K+ gradients, thus preserving cellular ion homeostasis. In multicellular organisms, this basic housekeeping function is integrated to fulfill the needs of specialized organs and preserve whole-body homeostasis. In vertebrates, Na+-K+-ATPase is essential for many fundamental physiological processes, such as nerve conduction, muscle contraction, nutrient absorption, and urine excretion. During vertebrate evolution, three key developments contributed to diversification and integration of Na+-K+-ATPase functions. Generation of novel α- and β-subunits led to formation of multiple Na+-K+-ATPase isoenyzmes with distinct functional characteristics. Development of a complex endocrine system enabled efficient coordination of diverse Na+-K+-ATPase functions. Emergence of FXYDs, small transmembrane proteins that regulate Na+-K+-ATPase, opened new ways to modulate its function. FXYDs are a vertebrate innovation and an important site of hormonal action, suggesting they played an especially prominent role in evolving interaction between Na+-K+-ATPase and the endocrine system in vertebrates.
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Cholesterol and the Safety Factor for Neuromuscular Transmission. Int J Mol Sci 2019; 20:ijms20051046. [PMID: 30823359 PMCID: PMC6429197 DOI: 10.3390/ijms20051046] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/23/2019] [Accepted: 02/24/2019] [Indexed: 12/12/2022] Open
Abstract
A present review is devoted to the analysis of literature data and results of own research. Skeletal muscle neuromuscular junction is specialized to trigger the striated muscle fiber contraction in response to motor neuron activity. The safety factor at the neuromuscular junction strongly depends on a variety of pre- and postsynaptic factors. The review focuses on the crucial role of membrane cholesterol to maintain a high efficiency of neuromuscular transmission. Cholesterol metabolism in the neuromuscular junction, its role in the synaptic vesicle cycle and neurotransmitter release, endplate electrogenesis, as well as contribution of cholesterol to the synaptogenesis, synaptic integrity, and motor disorders are discussed.
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Larsen BR, Stoica A, MacAulay N. Developmental maturation of activity-induced K + and pH transients and the associated extracellular space dynamics in the rat hippocampus. J Physiol 2019; 597:583-597. [PMID: 30357826 PMCID: PMC6332761 DOI: 10.1113/jp276768] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 10/22/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Neuronal activity induces fluctuation in extracellular space volume, [K+ ]o and pHo , the management of which influences neuronal function The neighbour astrocytes buffer the K+ and pH and swell during the process, causing shrinkage of the extracellular space In the present study, we report the developmental rise of the homeostatic control of the extracellular space dynamics, for which regulation becomes tighter with maturation and thus is proposed to ensure efficient synaptic transmission in the mature animals The extracellular space dynamics of volume, [K+ ]o and pHo evolve independently with developmental maturation and, although all of them are inextricably tied to neuronal activity, they do not couple directly. ABSTRACT Neuronal activity in the mammalian central nervous system associates with transient extracellular space (ECS) dynamics involving elevated K+ and pH and shrinkage of the ECS. These ECS properties affect membrane potentials, neurotransmitter concentrations and protein function and are thus anticipated to be under tight regulatory control. It remains unresolved to what extent these ECS dynamics are developmentally regulated as synaptic precision arises and whether they are directly or indirectly coupled. To resolve the development of homeostatic control of [K+ ]o , pH, and ECS and their interaction, we utilized ion-sensitive microelectrodes in electrically stimulated rat hippocampal slices from rats of different developmental stages (postnatal days 3-28). With the employed stimulation paradigm, the stimulus-evoked peak [K+ ]o and pHo transients were stable across age groups, until normalized to neuronal activity (field potential amplitude), in which case the K+ and pH shifted significantly more in the younger animals. By contrast, ECS dynamics increased with age until normalized to the field potential, and thus correlated with neuronal activity. With age, the animals not only managed the peak [K+ ]o better, but also displayed swifter post-stimulus removal of [K+ ]o , in correlation with the increased expression of the α1-3 isoforms of the Na+ /K+ -ATPase, and a swifter return of ECS volume. The different ECS dynamics approached a near-identical temporal pattern in the more mature animals. In conclusion, although these phenomena are inextricably tied to neuronal activity, our data suggest that they do not couple directly.
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Affiliation(s)
- Brian Roland Larsen
- Department of NeuroscienceFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Anca Stoica
- Department of NeuroscienceFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Nanna MacAulay
- Department of NeuroscienceFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
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Lin AW, Gill KK, Castañeda MS, Matucci I, Eder N, Claxton S, Flynn H, Snijders AP, George R, Ultanir SK. Chemical genetic identification of GAK substrates reveals its role in regulating Na +/K +-ATPase. Life Sci Alliance 2018; 1:e201800118. [PMID: 30623173 PMCID: PMC6312924 DOI: 10.26508/lsa.201800118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 12/07/2018] [Accepted: 12/10/2018] [Indexed: 12/15/2022] Open
Abstract
Novel GAK phosphorylation targets are identified using chemical genetic methods. One of the substrates is the α subunit of the Na+/K+-ATPase, phosphorylation of which is necessary for its surface trafficking from endosomes. Conserved functions of NAK family kinases are described. Cyclin G–associated kinase (GAK) is a ubiquitous serine/threonine kinase that facilitates clathrin uncoating during vesicle trafficking. GAK phosphorylates a coat adaptor component, AP2M1, to help achieve this function. GAK is also implicated in Parkinson's disease through genome-wide association studies. However, GAK's role in mammalian neurons remains unclear, and insight may come from identification of further substrates. Employing a chemical genetics method, we show here that the sodium potassium pump (Na+/K+-ATPase) α-subunit Atp1a3 is a GAK target and that GAK regulates Na+/K+-ATPase trafficking to the plasma membrane. Whole-cell patch clamp recordings from CA1 pyramidal neurons in GAK conditional knockout mice show a larger change in resting membrane potential when exposed to the Na+/K+-ATPase blocker ouabain, indicating compromised Na+/K+-ATPase function in GAK knockouts. Our results suggest a modulatory role for GAK via phosphoregulation of substrates such as Atp1a3 during cargo trafficking.
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Affiliation(s)
- Amy W Lin
- Kinase and Brain Development Lab, The Francis Crick Institute, London, United Kingdom
| | - Kalbinder K Gill
- Kinase and Brain Development Lab, The Francis Crick Institute, London, United Kingdom
| | | | - Irene Matucci
- Kinase and Brain Development Lab, The Francis Crick Institute, London, United Kingdom
| | - Noreen Eder
- Kinase and Brain Development Lab, The Francis Crick Institute, London, United Kingdom.,Mass Spectrometry Platform, The Francis Crick Institute, London, United Kingdom
| | - Suzanne Claxton
- Kinase and Brain Development Lab, The Francis Crick Institute, London, United Kingdom
| | - Helen Flynn
- Mass Spectrometry Platform, The Francis Crick Institute, London, United Kingdom
| | | | - Roger George
- Protein Purification Facility, The Francis Crick Institute, London, United Kingdom
| | - Sila K Ultanir
- Kinase and Brain Development Lab, The Francis Crick Institute, London, United Kingdom
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Yaoita Y, Nakajima K. Developmental gene expression patterns in the brain and liver of Xenopus tropicalis during metamorphosis climax. Genes Cells 2018; 23:998-1008. [PMID: 30294949 DOI: 10.1111/gtc.12647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/18/2018] [Accepted: 09/29/2018] [Indexed: 11/29/2022]
Abstract
Thyroid hormones (THs) induce metamorphosis in amphibians, causing dynamic changes, whereas mammalian newborns undergo environmental transition from placenta to open air at birth. The similarity between amphibian metamorphosis and the mammalian perinatal periods has been repeatedly discussed. However, a corresponding developmental gene expression analysis has not yet been reported. In this study, we examined the developmental gene expression profiles in the brain and liver of Xenopus tropicalis during metamorphosis climax and compared them to the respective gene expression profiles of newborn rodents. Many upregulated genes identified in the tadpole brain during metamorphosis are also upregulated in the rodent brain during the first three postnatal weeks when the TH surge occurs. The upregulation of some genes in the brain was inhibited in thyroid hormone receptor α (TRα) knockout tadpoles but not in TRβ-knockout tadpoles, implying that brain metamorphosis is mainly mediated by TRα. The expression of some genes was also increased in the liver during metamorphosis climax. Our data suggest that the rodent brain undergoes TH-dependent remodeling during the first three postnatal weeks as observed in X. tropicalis during the larva-to-adult metamorphosis.
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Affiliation(s)
- Yoshio Yaoita
- Division of Embryology, Amphibian Research Center, Hiroshima University, Higashihiroshima, Japan
| | - Keisuke Nakajima
- Division of Embryology, Amphibian Research Center, Hiroshima University, Higashihiroshima, Japan
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28
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Floyd RV, Mobasheri A, Wray S. Gestation changes sodium pump isoform expression, leading to changes in ouabain sensitivity, contractility, and intracellular calcium in rat uterus. Physiol Rep 2018; 5. [PMID: 29208689 PMCID: PMC5727280 DOI: 10.14814/phy2.13527] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 11/24/2022] Open
Abstract
Developmental and tissue‐specific differences in isoforms allow Na+, K+‐ATPase function to be tightly regulated, as they control sensitivity to ions and inhibitors. Uterine contraction relies on the activity of the Na+, K+ATPase, which creates ionic gradients that drive excitation‐contraction coupling. It is unknown whether Na+, K+ATPase isoforms are regulated throughout pregnancy or whether they have a direct role in modulating uterine contractility. We hypothesized that gestation‐dependent differential expression of isoforms would affect contractile responses to Na+, K+ATPase α subunit inhibition with ouabain. Our aims were therefore: (1) to determine the gestation‐dependent expression of mRNA transcripts, protein abundance and tissue distribution of Na+, K+ATPase isoforms in myometrium; (2) to investigate the functional effects of differential isoform expression via ouabain sensitivity; and (3) if changes in contractile responses can be explained by changes in intracellular [Ca2+]. Changes in abundance and distribution of the Na+, K+ATPase α, β and FXYD1 and 2 isoforms, were studied in rat uterus from nonpregnant, and early, mid‐, and term gestation. All α, β subunit isoforms (1,2,3) and FXYD1 were detected but FXYD2 was absent. The α1 and β1 isoforms were unchanged throughout pregnancy, whereas α2 and α3 significant decreased at term while β2 and FXYD1 significantly increased from mid‐term onwards. These changes in expression correlated with increased functional sensitivity to ouabain, and parallel changes in intracellular Ca2+, measured with Indo‐1. In conclusion, gestation induces specific regulatory changes in expression of Na+, K+ATPase isoforms in the uterus which influence contractility and may be related to the physiological requirements for successful pregnancy and delivery.
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Affiliation(s)
- Rachel V Floyd
- The Department of Molecular and Cellular Physiology, University of Liverpool, Liverpool, United Kingdom
| | - Ali Mobasheri
- Department of Veterinary Preclinical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Susan Wray
- The Department of Molecular and Cellular Physiology, University of Liverpool, Liverpool, United Kingdom
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Ding B, Walton JP, Zhu X, Frisina RD. Age-related changes in Na, K-ATPase expression, subunit isoform selection and assembly in the stria vascularis lateral wall of mouse cochlea. Hear Res 2018; 367:59-73. [PMID: 30029086 DOI: 10.1016/j.heares.2018.07.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 07/02/2018] [Accepted: 07/06/2018] [Indexed: 11/26/2022]
Abstract
Due to the critical role of cochlear ion channels for hearing, the focus of the present study was to examine age-related changes of Na, K-ATPase (NKA) subunits in the lateral wall of mouse cochlea. We combined qRT-PCR, western blot and immunocytochemistry methodologies in order to determine gene and protein expression levels in the lateral wall of young and aged CBA/CaJ mice. Of the seven NKA subunits, only the mRNA expressions of α1, β1 and β2 subunit isoforms were detected in the lateral wall of CBA/CaJ mice. Aging was accompanied by dys-regulation of gene and protein expression of all three subunits detected. Hematoxylin and eosin (H&E) staining revealed atrophy of the cochlear stria vascularis (SV). The SV atrophy rate (20%) was much less than the ∼80% decline in expression of all three NKA isoforms, indicating lateral wall atrophy and NKA dys-regulation are independent factors and that there is a combination of changes involving the morphology of SV and NKA expression in the aging cochlea which may concomitantly affect cochlear function. Immunoprecipitation assays showed that the α1-β1 heterodimer is the selective preferential heterodimer over the α1-β2 heterodimer in cochlea lateral wall. Interestingly, in vitro pathway experiments utilizing cultured mouse cochlear marginal cells from the SV (SV-K1 cells) indicated that decreased mRNA and protein expressions of α1, β1 and β2 subunit isoforms are not associated with reduction of NKA activity following in vitro application of ouabain, but ouabain did disrupt the α1-β1 heterodimer interaction. Lastly, the association between the α1 and β1 subunit isoforms was present in the cochlear lateral wall of young adult mice, but this interaction could not be detected in old mice. Taken together, these data suggest that in the young adult mouse there is a specific, functional selection and assembly of NKA subunit isoforms in the SV lateral wall, which is disrupted and dys-regulated with age. Interventions for this age-linked ion channel disruption may have the potential to help diagnose, prevent, or treat age-related hearing loss.
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Affiliation(s)
- Bo Ding
- Dept. Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - Joseph P Walton
- Dept. Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Dept. Chemical & Biomedical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA.
| | - Xiaoxia Zhu
- Dept. Chemical & Biomedical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - Robert D Frisina
- Dept. Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Dept. Chemical & Biomedical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Dept. Medical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
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Christiansen D, Murphy RM, Bangsbo J, Stathis CG, Bishop DJ. Increased FXYD1 and PGC-1α mRNA after blood flow-restricted running is related to fibre type-specific AMPK signalling and oxidative stress in human muscle. Acta Physiol (Oxf) 2018; 223:e13045. [PMID: 29383885 PMCID: PMC5969286 DOI: 10.1111/apha.13045] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 01/01/2018] [Accepted: 01/24/2018] [Indexed: 12/24/2022]
Abstract
Aim This study explored the effects of blood flow restriction (BFR) on mRNA responses of PGC‐1α (total, 1α1, and 1α4) and Na+,K+‐ATPase isoforms (NKA; α1‐3, β1‐3, and FXYD1) to an interval running session and determined whether these effects were related to increased oxidative stress, hypoxia, and fibre type‐specific AMPK and CaMKII signalling, in human skeletal muscle. Methods In a randomized, crossover fashion, 8 healthy men (26 ± 5 year and 57.4 ± 6.3 mL kg−1 min−1) completed 3 exercise sessions: without (CON) or with blood flow restriction (BFR), or in systemic hypoxia (HYP, ~3250 m). A muscle sample was collected before (Pre) and after exercise (+0 hour, +3 hours) to quantify mRNA, indicators of oxidative stress (HSP27 protein in type I and II fibres, and catalase and HSP70 mRNA), metabolites, and α‐AMPK Thr172/α‐AMPK, ACC Ser221/ACC, CaMKII Thr287/CaMKII, and PLBSer16/PLB ratios in type I and II fibres. Results Muscle hypoxia (assessed by near‐infrared spectroscopy) was matched between BFR and HYP, which was higher than CON (~90% vs ~70%; P < .05). The mRNA levels of FXYD1 and PGC‐1α isoforms (1α1 and 1α4) increased in BFR only (P < .05) and were associated with increases in indicators of oxidative stress and type I fibre ACC Ser221/ACC ratio, but dissociated from muscle hypoxia, lactate, and CaMKII signalling. Conclusion Blood flow restriction augmented exercise‐induced increases in muscle FXYD1 and PGC‐1α mRNA in men. This effect was related to increased oxidative stress and fibre type‐dependent AMPK signalling, but unrelated to the severity of muscle hypoxia, lactate accumulation, and modulation of fibre type‐specific CaMKII signalling.
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Affiliation(s)
- D. Christiansen
- Institute of Sport, Exercise and Active Living (ISEAL); Victoria University; Melbourne Vic. Australia
| | - R. M. Murphy
- Department of Biochemistry and Genetics; La Trobe Institute for Molecular Science; La Trobe University; Melbourne Vic. Australia
| | - J. Bangsbo
- Department of Nutrition, Exercise and Sports (NEXS); University of Copenhagen; Copenhagen N Denmark
| | - C. G. Stathis
- Institute of Sport, Exercise and Active Living (ISEAL); Victoria University; Melbourne Vic. Australia
| | - D. J. Bishop
- Institute of Sport, Exercise and Active Living (ISEAL); Victoria University; Melbourne Vic. Australia
- School of Medical and Health Sciences; Edith Cowan University; Perth WA Australia
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31
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Mechanism of noradrenaline-induced α1-adrenoceptor mediated regulation of Na-K ATPase subunit expression in Neuro-2a cells. Brain Res Bull 2018; 139:157-166. [DOI: 10.1016/j.brainresbull.2018.02.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 02/08/2018] [Accepted: 02/20/2018] [Indexed: 01/15/2023]
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32
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Kaur R, Sharma A, Sodhi M, Swami SK, Sharma VL, Kumari P, Verma P, Mukesh M. Sequence characterization of alpha 1 isoform (ATP1A1) of Na+/K+-ATPase gene and expression characteristics of its major isoforms across tissues of riverine buffaloes (Bubalus bubalis). GENE REPORTS 2018. [DOI: 10.1016/j.genrep.2017.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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33
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Ikeda K, Onimaru H, Kawakami K. Knockout of sodium pump α3 subunit gene ( Atp1a3 −/− ) results in perinatal seizure and defective respiratory rhythm generation. Brain Res 2017; 1666:27-37. [DOI: 10.1016/j.brainres.2017.04.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 04/02/2017] [Accepted: 04/21/2017] [Indexed: 10/19/2022]
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Mohammadi S, Savitzky AH, Lohr J, Dobler S. Toad toxin-resistant snake ( Thamnophis elegans ) expresses high levels of mutant Na + /K + -ATPase mRNA in cardiac muscle. Gene 2017; 614:21-25. [DOI: 10.1016/j.gene.2017.02.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/26/2017] [Accepted: 02/24/2017] [Indexed: 10/25/2022]
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35
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Petrov AM, Kravtsova VV, Matchkov VV, Vasiliev AN, Zefirov AL, Chibalin AV, Heiny JA, Krivoi II. Membrane lipid rafts are disturbed in the response of rat skeletal muscle to short-term disuse. Am J Physiol Cell Physiol 2017; 312:C627-C637. [PMID: 28274922 DOI: 10.1152/ajpcell.00365.2016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/22/2017] [Accepted: 03/05/2017] [Indexed: 12/19/2022]
Abstract
Marked loss of skeletal muscle mass occurs under various conditions of disuse, but the molecular and cellular mechanisms leading to atrophy are not completely understood. We investigate early molecular events that might play a role in skeletal muscle remodeling during mechanical unloading (disuse). The effects of acute (6-12 h) hindlimb suspension on the soleus muscles from adult rats were examined. The integrity of plasma membrane lipid rafts was tested utilizing cholera toxin B subunit or fluorescent sterols. In addition, resting intracellular Ca2+ level was analyzed. Acute disuse disturbed the plasma membrane lipid-ordered phase throughout the sarcolemma and was more pronounced in junctional membrane regions. Ouabain (1 µM), which specifically inhibits the Na-K-ATPase α2 isozyme in rodent skeletal muscles, produced similar lipid raft changes in control muscles but was ineffective in suspended muscles, which showed an initial loss of α2 Na-K-ATPase activity. Lipid rafts were able to recover with cholesterol supplementation, suggesting that disturbance results from cholesterol loss. Repetitive nerve stimulation also restores lipid rafts, specifically in the junctional sarcolemma region. Disuse locally lowered the resting intracellular Ca2+ concentration only near the neuromuscular junction of muscle fibers. Our results provide evidence to suggest that the ordering of lipid rafts strongly depends on motor nerve input and may involve interactions with the α2 Na-K-ATPase. Lipid raft disturbance, accompanied by intracellular Ca2+ dysregulation, is among the earliest remodeling events induced by skeletal muscle disuse.
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Affiliation(s)
- Alexey M Petrov
- Department of Normal Physiology, Kazan State Medical University, Kazan, Russia
| | - Violetta V Kravtsova
- Department of General Physiology, St. Petersburg State University, St. Petersburg, Russia
| | | | - Alexander N Vasiliev
- Department of General Physiology, St. Petersburg State University, St. Petersburg, Russia
| | - Andrey L Zefirov
- Department of Normal Physiology, Kazan State Medical University, Kazan, Russia
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden; and
| | - Judith A Heiny
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University, St. Petersburg, Russia;
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Stanley CM, Gagnon DG, Bernal A, Meyer DJ, Rosenthal JJ, Artigas P. Importance of the Voltage Dependence of Cardiac Na/K ATPase Isozymes. Biophys J 2016; 109:1852-62. [PMID: 26536262 DOI: 10.1016/j.bpj.2015.09.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/11/2015] [Accepted: 09/10/2015] [Indexed: 11/25/2022] Open
Abstract
Cardiac cells express more than one isoform of the Na, K-ATPase (NKA), the heteromeric enzyme that creates the Na(+) and K(+) gradients across the plasmalemma. Cardiac isozymes contain one catalytic α-subunit isoform (α1, α2, or α3) associated with an auxiliary β-subunit isoform (β1 or β2). Past studies using biochemical approaches have revealed minor kinetic differences between isozymes formed by different α-β isoform combinations; these results make it difficult to understand the physiological requirement for multiple isoforms. In intact cells, however, NKA enzymes operate in a more complex environment, which includes a substantial transmembrane potential. We evaluated the voltage dependence of human cardiac NKA isozymes expressed in Xenopus oocytes, and of native NKA isozymes in rat ventricular myocytes, using normal mammalian physiological concentrations of Na(+)o and K(+)o. We demonstrate that although α1 and α3 pumps are functional at all physiologically relevant voltages, α2β1 pumps and α2β2 pumps are inhibited by ∼75% and ∼95%, respectively, at resting membrane potentials, and only activate appreciably upon depolarization. Furthermore, phospholemman (FXYD1) inhibits pump function without significantly altering the pump's voltage dependence. Our observations provide a simple explanation for the physiological relevance of the α2 subunit (∼20% of total α subunits in rat ventricle): they act as a reserve and are recruited into action for extra pumping during the long-lasting cardiac action potential, where most of the Na(+) entry occurs. This strong voltage dependence of α2 pumps also helps explain how cardiotonic steroids, which block NKA pumps, can be a beneficial treatment for heart failure: by only inhibiting the α2 pumps, they selectively reduce NKA activity during the cardiac action potential, leading to an increase in systolic Ca(2+), due to reduced extrusion through the Na/Ca exchanger, without affecting resting Na(+) and Ca(2+) concentrations.
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Affiliation(s)
- Christopher M Stanley
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Dominique G Gagnon
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas; Department of Physics, Texas Tech University, Lubbock, Texas
| | - Adam Bernal
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Dylan J Meyer
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Joshua J Rosenthal
- Universidad de Puerto Rico, Recinto de Ciencias Médicas, Instituto de Neurobiología, San Juan, Puerto Rico
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas.
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Capuani C, Melone M, Tottene A, Bragina L, Crivellaro G, Santello M, Casari G, Conti F, Pietrobon D. Defective glutamate and K+ clearance by cortical astrocytes in familial hemiplegic migraine type 2. EMBO Mol Med 2016; 8:967-86. [PMID: 27354390 PMCID: PMC4967947 DOI: 10.15252/emmm.201505944] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Migraine is a common disabling brain disorder. A subtype of migraine with aura (familial hemiplegic migraine type 2: FHM2) is caused by loss‐of‐function mutations in α2 Na+,K+ATPase (α2NKA), an isoform almost exclusively expressed in astrocytes in adult brain. Cortical spreading depression (CSD), the phenomenon that underlies migraine aura and activates migraine headache mechanisms, is facilitated in heterozygous FHM2‐knockin mice with reduced expression of α2NKA. The mechanisms underlying an increased susceptibility to CSD in FHM2 are unknown. Here, we show reduced rates of glutamate and K+ clearance by cortical astrocytes during neuronal activity and reduced density of GLT‐1a glutamate transporters in cortical perisynaptic astrocytic processes in heterozygous FHM2‐knockin mice, demonstrating key physiological roles of α2NKA and supporting tight coupling with GLT‐1a. Using ceftriaxone treatment of FHM2 mutants and partial inhibition of glutamate transporters in wild‐type mice, we obtain evidence that defective glutamate clearance can account for most of the facilitation of CSD initiation in FHM2‐knockin mice, pointing to excessive glutamatergic transmission as a key mechanism underlying the vulnerability to CSD ignition in migraine.
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Affiliation(s)
- Clizia Capuani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marcello Melone
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy Center for Neurobiology of Aging, INRCA IRCCS, Ancona, Italy
| | - Angelita Tottene
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Luca Bragina
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy Center for Neurobiology of Aging, INRCA IRCCS, Ancona, Italy
| | | | - Mirko Santello
- Institute of Pharmacology and Toxicology, University of Zurich, Zürich, Switzerland
| | - Giorgio Casari
- Vita-Salute San Raffaele University and San Raffaele Scientific Institute, Milano, Italy
| | - Fiorenzo Conti
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy Center for Neurobiology of Aging, INRCA IRCCS, Ancona, Italy Fondazione di Medicina Molecolare, Università Politecnica delle Marche, Ancona, Italy
| | - Daniela Pietrobon
- Department of Biomedical Sciences, University of Padova, Padova, Italy CNR Institute of Neuroscience, Padova, Italy
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Pirkmajer S, Chibalin AV. Na,K-ATPase regulation in skeletal muscle. Am J Physiol Endocrinol Metab 2016; 311:E1-E31. [PMID: 27166285 DOI: 10.1152/ajpendo.00539.2015] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 05/02/2016] [Indexed: 12/17/2022]
Abstract
Skeletal muscle contains one of the largest and the most dynamic pools of Na,K-ATPase (NKA) in the body. Under resting conditions, NKA in skeletal muscle operates at only a fraction of maximal pumping capacity, but it can be markedly activated when demands for ion transport increase, such as during exercise or following food intake. Given the size, capacity, and dynamic range of the NKA pool in skeletal muscle, its tight regulation is essential to maintain whole body homeostasis as well as muscle function. To reconcile functional needs of systemic homeostasis with those of skeletal muscle, NKA is regulated in a coordinated manner by extrinsic stimuli, such as hormones and nerve-derived factors, as well as by local stimuli arising in skeletal muscle fibers, such as contractions and muscle energy status. These stimuli regulate NKA acutely by controlling its enzymatic activity and/or its distribution between the plasma membrane and the intracellular storage compartment. They also regulate NKA chronically by controlling NKA gene expression, thus determining total NKA content in skeletal muscle and its maximal pumping capacity. This review focuses on molecular mechanisms that underlie regulation of NKA in skeletal muscle by major extrinsic and local stimuli. Special emphasis is given to stimuli and mechanisms linking regulation of NKA and energy metabolism in skeletal muscle, such as insulin and the energy-sensing AMP-activated protein kinase. Finally, the recently uncovered roles for glutathionylation, nitric oxide, and extracellular K(+) in the regulation of NKA in skeletal muscle are highlighted.
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Affiliation(s)
- Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; and
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
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Matchkov VV, Krivoi II. Specialized Functional Diversity and Interactions of the Na,K-ATPase. Front Physiol 2016; 7:179. [PMID: 27252653 PMCID: PMC4879863 DOI: 10.3389/fphys.2016.00179] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/04/2016] [Indexed: 12/22/2022] Open
Abstract
Na,K-ATPase is a protein ubiquitously expressed in the plasma membrane of all animal cells and vitally essential for their functions. A specialized functional diversity of the Na,K-ATPase isozymes is provided by molecular heterogeneity, distinct subcellular localizations, and functional interactions with molecular environment. Studies over the last decades clearly demonstrated complex and isoform-specific reciprocal functional interactions between the Na,K-ATPase and neighboring proteins and lipids. These interactions are enabled by a spatially restricted ion homeostasis, direct protein-protein/lipid interactions, and protein kinase signaling pathways. In addition to its "classical" function in ion translocation, the Na,K-ATPase is now considered as one of the most important signaling molecules in neuronal, epithelial, skeletal, cardiac and vascular tissues. Accordingly, the Na,K-ATPase forms specialized sub-cellular multimolecular microdomains which act as receptors to circulating endogenous cardiotonic steroids (CTS) triggering a number of signaling pathways. Changes in these endogenous cardiotonic steroid levels and initiated signaling responses have significant adaptive values for tissues and whole organisms under numerous physiological and pathophysiological conditions. This review discusses recent progress in the studies of functional interactions between the Na,K-ATPase and molecular microenvironment, the Na,K-ATPase-dependent signaling pathways and their significance for diversity of cell function.
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Affiliation(s)
| | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University St. Petersburg, Russia
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Larsen BR, Stoica A, MacAulay N. Managing Brain Extracellular K(+) during Neuronal Activity: The Physiological Role of the Na(+)/K(+)-ATPase Subunit Isoforms. Front Physiol 2016; 7:141. [PMID: 27148079 PMCID: PMC4841311 DOI: 10.3389/fphys.2016.00141] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/04/2016] [Indexed: 11/13/2022] Open
Abstract
During neuronal activity in the brain, extracellular K+ rises and is subsequently removed to prevent a widespread depolarization. One of the key players in regulating extracellular K+ is the Na+/K+-ATPase, although the relative involvement and physiological impact of the different subunit isoform compositions of the Na+/K+-ATPase remain unresolved. The various cell types in the brain serve a certain temporal contribution in the face of network activity; astrocytes respond directly to the immediate release of K+ from neurons, whereas the neurons themselves become the primary K+ absorbers as activity ends. The kinetic characteristics of the catalytic α subunit isoforms of the Na+/K+-ATPase are, partly, determined by the accessory β subunit with which they combine. The isoform combinations expressed by astrocytes and neurons, respectively, appear to be in line with the kinetic characteristics required to fulfill their distinct physiological roles in clearance of K+ from the extracellular space in the face of neuronal activity. Understanding the nature, impact and effects of the various Na+/K+-ATPase isoform combinations in K+ management in the central nervous system might reveal insights into pathological conditions such as epilepsy, migraine, and spreading depolarization following cerebral ischemia. In addition, particular neurological diseases occur as a result of mutations in the α2- (familial hemiplegic migraine type 2) and α3 isoforms (rapid-onset dystonia parkinsonism/alternating hemiplegia of childhood). This review addresses aspects of the Na+/K+-ATPase in the regulation of extracellular K+ in the central nervous system as well as the related pathophysiology. Understanding the physiological setting in non-pathological tissue would provide a better understanding of the pathological events occurring during disease.
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Affiliation(s)
- Brian Roland Larsen
- Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark
| | - Anca Stoica
- Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark
| | - Nanna MacAulay
- Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark
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Pirkmajer S, Chibalin AV. NO turns on Na,K-ATPase in skeletal muscle. Acta Physiol (Oxf) 2016; 216:386-91. [PMID: 26786181 DOI: 10.1111/apha.12652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- S. Pirkmajer
- Institute of Pathophysiology; Faculty of Medicine; University of Ljubljana; Ljubljana Slovenia
| | - A. V. Chibalin
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Stockholm Sweden
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Kravtsova VV, Petrov AM, Matchkov VV, Bouzinova EV, Vasiliev AN, Benziane B, Zefirov AL, Chibalin AV, Heiny JA, Krivoi II. Distinct α2 Na,K-ATPase membrane pools are differently involved in early skeletal muscle remodeling during disuse. ACTA ACUST UNITED AC 2016; 147:175-88. [PMID: 26755774 PMCID: PMC4727944 DOI: 10.1085/jgp.201511494] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 12/22/2015] [Indexed: 11/29/2022]
Abstract
Location, location, location. The Na-K pump of skeletal muscle is regulated differently at neuromuscular junctions. The Na,K-ATPase is essential for the contractile function of skeletal muscle, which expresses the α1 and α2 subunit isoforms of Na,K-ATPase. The α2 isozyme is predominant in adult skeletal muscles and makes a greater contribution in working compared with noncontracting muscles. Hindlimb suspension (HS) is a widely used model of muscle disuse that leads to progressive atrophy of postural skeletal muscles. This study examines the consequences of acute (6–12 h) HS on the functioning of the Na,K-ATPase α1 and α2 isozymes in rat soleus (disused) and diaphragm (contracting) muscles. Acute disuse dynamically and isoform-specifically regulates the electrogenic activity, protein, and mRNA content of Na,K-ATPase α2 isozyme in rat soleus muscle. Earlier disuse-induced remodeling events also include phospholemman phosphorylation as well as its increased abundance and association with α2 Na,K-ATPase. The loss of α2 Na,K-ATPase activity results in reduced electrogenic pump transport and depolarized resting membrane potential. The decreased α2 Na,K-ATPase activity is caused by a decrease in enzyme activity rather than by altered protein and mRNA content, localization in the sarcolemma, or functional interaction with the nicotinic acetylcholine receptors. The loss of extrajunctional α2 Na,K-ATPase activity depends strongly on muscle use, and even the increased protein and mRNA content as well as enhanced α2 Na,K-ATPase abundance at this membrane region after 12 h of HS cannot counteract this sustained inhibition. In contrast, additional factors may regulate the subset of junctional α2 Na,K-ATPase pool that is able to recover during HS. Notably, acute, low-intensity muscle workload restores functioning of both α2 Na,K-ATPase pools. These results demonstrate that the α2 Na,K-ATPase in rat skeletal muscle is dynamically and acutely regulated by muscle use and provide the first evidence that the junctional and extrajunctional pools of the α2 Na,K-ATPase are regulated differently.
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Affiliation(s)
- Violetta V Kravtsova
- Department of General Physiology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Alexey M Petrov
- Department of Normal Physiology, Kazan State Medical University, Kazan 420012, Russia
| | | | - Elena V Bouzinova
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, 8240 Risskov, Denmark
| | - Alexander N Vasiliev
- Department of General Physiology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Boubacar Benziane
- Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Andrey L Zefirov
- Department of Normal Physiology, Kazan State Medical University, Kazan 420012, Russia
| | - Alexander V Chibalin
- Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Judith A Heiny
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267
| | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University, St. Petersburg 199034, Russia
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Li Z, Langhans SA. Transcriptional regulators of Na,K-ATPase subunits. Front Cell Dev Biol 2015; 3:66. [PMID: 26579519 PMCID: PMC4620432 DOI: 10.3389/fcell.2015.00066] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 10/05/2015] [Indexed: 12/20/2022] Open
Abstract
The Na,K-ATPase classically serves as an ion pump creating an electrochemical gradient across the plasma membrane that is essential for transepithelial transport, nutrient uptake and membrane potential. In addition, Na,K-ATPase also functions as a receptor, a signal transducer and a cell adhesion molecule. With such diverse roles, it is understandable that the Na,K-ATPase subunits, the catalytic α-subunit, the β-subunit and the FXYD proteins, are controlled extensively during development and to accommodate physiological needs. The spatial and temporal expression of Na,K-ATPase is partially regulated at the transcriptional level. Numerous transcription factors, hormones, growth factors, lipids, and extracellular stimuli modulate the transcription of the Na,K-ATPase subunits. Moreover, epigenetic mechanisms also contribute to the regulation of Na,K-ATPase expression. With the ever growing knowledge about diseases associated with the malfunction of Na,K-ATPase, this review aims at summarizing the best-characterized transcription regulators that modulate Na,K-ATPase subunit levels. As abnormal expression of Na,K-ATPase subunits has been observed in many carcinoma, we will also discuss transcription factors that are associated with epithelial-mesenchymal transition, a crucial step in the progression of many tumors to malignant disease.
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Affiliation(s)
- Zhiqin Li
- Nemours Center for Childhood Cancer Research, Nemours/Alfred I. duPont Hospital for Children Wilmington, DE, USA
| | - Sigrid A Langhans
- Nemours Center for Childhood Cancer Research, Nemours/Alfred I. duPont Hospital for Children Wilmington, DE, USA
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Manoharan P, Radzyukevich TL, Hakim Javadi H, Stiner CA, Landero Figueroa JA, Lingrel JB, Heiny JA. Phospholemman is not required for the acute stimulation of Na⁺-K⁺-ATPase α₂-activity during skeletal muscle fatigue. Am J Physiol Cell Physiol 2015; 309:C813-22. [PMID: 26468207 DOI: 10.1152/ajpcell.00205.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 09/08/2015] [Indexed: 11/22/2022]
Abstract
The Na(+)-K(+)-ATPase α2-isoform in skeletal muscle is rapidly stimulated during muscle use and plays a critical role in fatigue resistance. The acute mechanisms that stimulate α2-activity are not completely known. This study examines whether phosphorylation of phospholemman (PLM/FXYD1), a regulatory subunit of Na(+)-K(+)-ATPase, plays a role in the acute stimulation of α2 in working muscles. Mice lacking PLM (PLM KO) have a normal content of the α2-subunit and show normal exercise capacity, in contrast to the greatly reduced exercise capacity of mice that lack α2 in the skeletal muscles. Nerve-evoked contractions in vivo did not induce a change in total PLM or PLM phosphorylated at Ser63 or Ser68, in either WT or PLM KO. Isolated muscles of PLM KO mice maintain contraction and resist fatigue as well as wild type (WT). Rb(+) transport by the α2-Na(+)-K(+)-ATPase is stimulated to the same extent in contracting WT and contracting PLM KO muscles. Phosphorylation of sarcolemmal membranes prepared from WT but not PLM KO skeletal muscles stimulates the activity of both α1 and α2 in a PLM-dependent manner. The stimulation occurs by an increase in Na(+) affinity without significant change in Vmax and is more effective for α1 than α2. These results demonstrate that phosphorylation of PLM is capable of stimulating the activity of both isozymes in skeletal muscle; however, contractile activity alone is not sufficient to induce PLM phosphorylation. Importantly, acute stimulation of α2, sufficient to support exercise and oppose fatigue, does not require PLM or its phosphorylation.
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Affiliation(s)
- Palanikumar Manoharan
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio
| | - Tatiana L Radzyukevich
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio; and
| | - Hesamedin Hakim Javadi
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio; and
| | - Cory A Stiner
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio
| | | | - Jerry B Lingrel
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio
| | - Judith A Heiny
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio; and
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DiFranco M, Hakimjavadi H, Lingrel JB, Heiny JA. Na,K-ATPase α2 activity in mammalian skeletal muscle T-tubules is acutely stimulated by extracellular K+. ACTA ACUST UNITED AC 2015; 146:281-94. [PMID: 26371210 PMCID: PMC4586590 DOI: 10.1085/jgp.201511407] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 08/21/2015] [Indexed: 11/20/2022]
Abstract
The K+ affinity of the Na,K-ATPase α2 isoform matches its activity to the range of extracellular K+ concentrations in the T-tubules at rest and during contraction, maintaining the excitability of active muscle. The Na,K-ATPase α2 isoform is the predominant Na,K-ATPase in adult skeletal muscle and the sole Na,K-ATPase in the transverse tubules (T-tubules). In quiescent muscles, the α2 isozyme operates substantially below its maximal transport capacity. Unlike the α1 isoform, the α2 isoform is not required for maintaining resting ion gradients or the resting membrane potential, canonical roles of the Na,K-ATPase in most other cells. However, α2 activity is stimulated immediately upon the start of contraction and, in working muscles, its contribution is crucial to maintaining excitation and resisting fatigue. Here, we show that α2 activity is determined in part by the K+ concentration in the T-tubules, through its K+ substrate affinity. Apparent K+ affinity was determined from measurements of the K1/2 for K+ activation of pump current in intact, voltage-clamped mouse flexor digitorum brevis muscle fibers. Pump current generated by the α2 Na,K-ATPase, Ip, was identified as the outward current activated by K+ and inhibited by micromolar ouabain. Ip was outward at all potentials studied (−90 to −30 mV) and increased with depolarization in the subthreshold range, −90 to −50 mV. The Q10 was 2.1 over the range of 22–37°C. The K1/2,K of Ip was 4.3 ± 0.3 mM at −90 mV and was relatively voltage independent. This K+ affinity is lower than that reported for other cell types but closely matches the dynamic range of extracellular K+ concentrations in the T-tubules. During muscle contraction, T-tubule luminal K+ increases in proportion to the frequency and duration of action potential firing. This K1/2,K predicts a low fractional occupancy of K+ substrate sites at the resting extracellular K+ concentration, with occupancy increasing in proportion to the frequency of membrane excitation. The stimulation of preexisting pumps by greater K+ site occupancy thus provides a rapid mechanism for increasing α2 activity in working muscles.
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Affiliation(s)
- Marino DiFranco
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Hesamedin Hakimjavadi
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267
| | - Jerry B Lingrel
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267
| | - Judith A Heiny
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267
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Rapid Eye Movement Sleep Deprivation Associated Increase in Na-K ATPase Activity in the Rat Brain is Due to Noradrenaline Induced α1-Adrenoceptor Mediated Increased α-Subunit of the Enzyme. Neurochem Res 2015; 40:1747-57. [DOI: 10.1007/s11064-015-1660-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/29/2015] [Accepted: 07/01/2015] [Indexed: 10/23/2022]
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Ching B, Woo JM, Hiong KC, Boo MV, Choo CYL, Wong WP, Chew SF, Ip YK. Na+/K+-ATPase α-subunit (nkaα) isoforms and their mRNA expression levels, overall Nkaα protein abundance, and kinetic properties of Nka in the skeletal muscle and three electric organs of the electric eel, Electrophorus electricus. PLoS One 2015; 10:e0118352. [PMID: 25793901 PMCID: PMC4368207 DOI: 10.1371/journal.pone.0118352] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/14/2015] [Indexed: 11/18/2022] Open
Abstract
This study aimed to obtain the coding cDNA sequences of Na+/K+-ATPase α (nkaα) isoforms from, and to quantify their mRNA expression in, the skeletal muscle (SM), the main electric organ (EO), the Hunter’s EO and the Sach’s EO of the electric eel, Electrophorus electricus. Four nkaα isoforms (nkaα1c1, nkaα1c2, nkaα2 and nkaα3) were obtained from the SM and the EOs of E. electricus. Based on mRNA expression levels, the major nkaα expressed in the SM and the three EOs of juvenile and adult E. electricus were nkaα1c1 and nkaα2, respectively. Molecular characterization of the deduced Nkaα1c1 and Nkaα2 sequences indicates that they probably have different affinities to Na+ and K+. Western blotting demonstrated that the protein abundance of Nkaα was barely detectable in the SM, but strongly detected in the main and Hunter’s EOs and weakly in the Sach’s EO of juvenile and adult E. electricus. These results corroborate the fact that the main EO and Hunter’s EO have high densities of Na+ channels and produce high voltage discharges while the Sach’s EO produces low voltage discharges. More importantly, there were significant differences in kinetic properties of Nka among the three EOs of juvenile E. electricus. The highest and lowest Vmax of Nka were detected in the main EO and the Sach’s EO, respectively, with the Hunter’s EO having a Vmax value intermediate between the two, indicating that the metabolic costs of EO discharge could be the highest in the main EO. Furthermore, the Nka from the main EO had the lowest Km (or highest affinity) for Na+ and K+ among the three EOs, suggesting that the Nka of the main EO was more effective than those of the other two EOs in maintaining intracellular Na+ and K+ homeostasis and in clearing extracellular K+ after EO discharge.
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Affiliation(s)
- Biyun Ching
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Republic of Singapore
| | - Jia M. Woo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Republic of Singapore
| | - Kum C. Hiong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Republic of Singapore
| | - Mel V. Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Republic of Singapore
| | - Celine Y. L. Choo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Republic of Singapore
| | - Wai P. Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Republic of Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore, 637616, Republic of Singapore
| | - Yuen K. Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Republic of Singapore
- The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore, 119227, Republic of Singapore
- * E-mail:
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Isoform-specific Na,K-ATPase alterations precede disuse-induced atrophy of rat soleus muscle. BIOMED RESEARCH INTERNATIONAL 2015; 2015:720172. [PMID: 25654120 PMCID: PMC4309216 DOI: 10.1155/2015/720172] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/18/2014] [Indexed: 11/17/2022]
Abstract
This study examines the isoform-specific effects of short-term hindlimb suspension (HS) on the Na,K-ATPase in rat soleus muscle. Rats were exposed to 24–72 h of HS and we analyzed the consequences on soleus muscle mass and contractile parameters; excitability and the resting membrane potential (RMP) of muscle fibers; the electrogenic activity, protein, and mRNA content of the α1 and α2 Na,K-ATPase; the functional activity and plasma membrane localization of the α2 Na,K-ATPase. Our results indicate that 24–72 h of HS specifically decreases the electrogenic activity of the Na,K-ATPase α2 isozyme and the RMP of soleus muscle fibers. This decrease occurs prior to muscle atrophy or any change in contractile parameters. The α2 mRNA and protein content increased after 24 h of HS and returned to initial levels at 72 h; however, even the increased content was not able to restore α2 enzyme activity in the disused soleus muscle. There was no change in the membrane localization of α2 Na,K-ATPase. The α1 Na,K-ATPase electrogenic activity, protein and mRNA content did not change. Our findings suggest that skeletal muscle use is absolutely required for α2 Na,K-ATPase transport activity and provide the first evidence that Na,K-ATPase alterations precede HS-induced muscle atrophy.
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Molecular mechanism of regulation of villus cell Na-K-ATPase in the chronically inflamed mammalian small intestine. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:702-11. [PMID: 25462166 DOI: 10.1016/j.bbamem.2014.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 11/03/2014] [Accepted: 11/06/2014] [Indexed: 11/24/2022]
Abstract
Na-K-ATPase located on the basolateral membrane (BLM) of intestinal epithelial cells provides a favorable intracellular Na+ gradient to promote all Na dependent co-transport processes across the brush border membrane (BBM). Down-regulation of Na-K-ATPase activity has been postulated to alter the absorption via Na-solute co-transporters in human inflammatory bowel disease (IBD). Further, the altered activity of a variety of Na-solute co-transporters in intact villus cells has been reported in animal models of chronic enteritis. But the molecular mechanism of down-regulation of Na-K-ATPase is not known. In the present study, using a rabbit model of chronic intestinal inflammation, which resembles human IBD, Na-K-ATPase in villus cells was shown to decrease. The relative mRNA abundance of α-1 and β-1 subunits was not altered in villus cells during chronic intestinal inflammation. Similarly, the protein levels of these subunits were also not altered in villus cells during chronic enteritis. However, the BLM concentration of α-1 and β-1 subunits was diminished in the chronically inflamed intestinal villus cells. An ankyrin-spectrin skeleton is necessary for the proper trafficking of Na-K-ATPase to the BLM of the cell. In the present study, ankyrin expression was markedly diminished in villus cells from the chronically inflamed intestine resulting in depolarization of ankyrin-G protein. The decrease of Na-K-ATPase activity was comparable to that seen in ankyrin knockdown IEC-18 cells. Therefore, altered localization of Na-K-ATPase as a result of transcriptional down-regulation of ankyrin-G mediates the down-regulation of Na-K-ATPase activity during chronic intestinal inflammation.
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