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Feng W, Lopez JR, Antrobus S, Zheng J, Uryash A, Dong Y, Beqollari D, Bannister RA, Hopkins PM, Beam KG, Allen PD, Pessah IN. Putative malignant hyperthermia mutation Ca V1.1-R174W is insufficient to trigger a fulminant response to halothane or confer heat stress intolerance. J Biol Chem 2023; 299:104992. [PMID: 37392848 PMCID: PMC10413282 DOI: 10.1016/j.jbc.2023.104992] [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: 04/04/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/03/2023] Open
Abstract
Malignant hyperthermia susceptibility (MHS) is an autosomal dominant pharmacogenetic disorder that manifests as a hypermetabolic state when carriers are exposed to halogenated volatile anesthetics or depolarizing muscle relaxants. In animals, heat stress intolerance is also observed. MHS is linked to over 40 variants in RYR1 that are classified as pathogenic for diagnostic purposes. More recently, a few rare variants linked to the MHS phenotype have been reported in CACNA1S, which encodes the voltage-activated Ca2+ channel CaV1.1 that conformationally couples to RyR1 in skeletal muscle. Here, we describe a knock-in mouse line that expresses one of these putative variants, CaV1.1-R174W. Heterozygous (HET) and homozygous (HOM) CaV1.1-R174W mice survive to adulthood without overt phenotype but fail to trigger with fulminant malignant hyperthermia when exposed to halothane or moderate heat stress. All three genotypes (WT, HET, and HOM) express similar levels of CaV1.1 by quantitative PCR, Western blot, [3H]PN200-110 receptor binding and immobilization-resistant charge movement densities in flexor digitorum brevis fibers. Although HOM fibers have negligible CaV1.1 current amplitudes, HET fibers have similar amplitudes to WT, suggesting a preferential accumulation of the CaV1.1-WT protein at triad junctions in HET animals. Never-the-less both HET and HOM have slightly elevated resting free Ca2+ and Na+ measured with double barreled microelectrode in vastus lateralis that is disproportional to upregulation of transient receptor potential canonical (TRPC) 3 and TRPC6 in skeletal muscle. CaV1.1-R174W and upregulation of TRPC3/6 alone are insufficient to trigger fulminant malignant hyperthermia response to halothane and/or heat stress in HET and HOM mice.
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Affiliation(s)
- Wei Feng
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Jose R Lopez
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA; Department of Research, Mount Sinai Medical Center, Miami Beach, Florida, USA
| | - Shane Antrobus
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Jing Zheng
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Arkady Uryash
- Department of Research, Mount Sinai Medical Center, Miami Beach, Florida, USA
| | - Yao Dong
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Donald Beqollari
- Department of Medicine-Cardiology Division, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Roger A Bannister
- Department of Medicine-Cardiology Division, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Philip M Hopkins
- Institute of Medical Research at St James's, University of Leeds, Leeds, United Kingdom
| | - Kurt G Beam
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Paul D Allen
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA; Institute of Medical Research at St James's, University of Leeds, Leeds, United Kingdom
| | - Isaac N Pessah
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA.
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Nemirovskaya TL, Sharlo KA. Roles of ATP and SERCA in the Regulation of Calcium Turnover in Unloaded Skeletal Muscles: Current View and Future Directions. Int J Mol Sci 2022; 23:ijms23136937. [PMID: 35805949 PMCID: PMC9267070 DOI: 10.3390/ijms23136937] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 06/20/2022] [Indexed: 11/16/2022] Open
Abstract
A decrease in skeletal muscle contractile activity or its complete cessation (muscle unloading or disuse) leads to muscle fibers’ atrophy and to alterations in muscle performance. These changes negatively affect the quality of life of people who, for one reason or another, are forced to face a limitation of physical activity. One of the key regulatory events leading to the muscle disuse-induced changes is an impairment of calcium homeostasis, which leads to the excessive accumulation of calcium ions in the sarcoplasm. This review aimed to analyze the triggering mechanisms of calcium homeostasis impairment (including those associated with the accumulation of high-energy phosphates) under various types of muscle unloading. Here we proposed a hypothesis about the regulatory mechanisms of SERCA and IP3 receptors activity during muscle unloading, and about the contribution of these mechanisms to the excessive calcium ion myoplasmic accumulation and gene transcription regulation via excitation–transcription coupling.
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Disturbance of calcium homeostasis and myogenesis caused by TET2 deletion in muscle stem cells. Cell Death Dis 2022; 8:236. [PMID: 35490157 PMCID: PMC9056526 DOI: 10.1038/s41420-022-01041-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/16/2022] [Accepted: 04/21/2022] [Indexed: 01/22/2023]
Abstract
Skeletal muscle myogenesis is a sophisticated process controlled by genetic and epigenetic regulators. In animals, one of the key enzymes for the DNA demethylation of 5-methylcytosine is TET2. Although TET2 is essential for muscle development, the mechanisms by which TET2 regulates myogenesis, particularly the implication for muscle stem cells, remains unclear. In the present study, we employed the TET2 knockout mouse model to investigate the function of TET2 in muscle development and regeneration. We observed that TET2 deficiency caused impaired muscle stem cell proliferation and differentiation, resulting in the reduction in both myofiber number and muscle tissue size. Specifically, TET2 maintains calcium homeostasis in muscle stem cells by controlling the DNA methylation levels of the calcium pathway genes. Forced expression of the sodium/calcium exchanger protein SLC8A3 could rescue the myogenic defects in TET2 knockout cells. Our data not only illustrated the vital function of TET2 during myogenesis but also identified novel targets that contribute to calcium homeostasis for enhancing muscle function.
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Rossi D, Pierantozzi E, Amadsun DO, Buonocore S, Rubino EM, Sorrentino V. The Sarcoplasmic Reticulum of Skeletal Muscle Cells: A Labyrinth of Membrane Contact Sites. Biomolecules 2022; 12:488. [PMID: 35454077 PMCID: PMC9026860 DOI: 10.3390/biom12040488] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/14/2022] [Accepted: 03/18/2022] [Indexed: 12/17/2022] Open
Abstract
The sarcoplasmic reticulum of skeletal muscle cells is a highly ordered structure consisting of an intricate network of tubules and cisternae specialized for regulating Ca2+ homeostasis in the context of muscle contraction. The sarcoplasmic reticulum contains several proteins, some of which support Ca2+ storage and release, while others regulate the formation and maintenance of this highly convoluted organelle and mediate the interaction with other components of the muscle fiber. In this review, some of the main issues concerning the biology of the sarcoplasmic reticulum will be described and discussed; particular attention will be addressed to the structure and function of the two domains of the sarcoplasmic reticulum supporting the excitation-contraction coupling and Ca2+-uptake mechanisms.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy; (E.P.); (D.O.A.); (S.B.); (E.M.R.); (V.S.)
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Mijares A, Allen PD, Lopez JR. Senescence Is Associated With Elevated Intracellular Resting [Ca 2 +] in Mice Skeletal Muscle Fibers. An in vivo Study. Front Physiol 2021; 11:601189. [PMID: 33510646 PMCID: PMC7837333 DOI: 10.3389/fphys.2020.601189] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/23/2020] [Indexed: 11/13/2022] Open
Abstract
Aging causes skeletal muscles to become atrophied, weak, and easily fatigued. Here, we have tested the hypothesis that normal aging in skeletal muscle cells is associated with Ca2+ intracellular dyshomeostasis and oxidative stress. Intracellular Ca2+ concentration ([Ca2+]i), resting intracellular Na+ concentration ([Na+]i) and reactive oxygen species (ROS) production were measured in vivo (superficial gastrocnemius fibers) using double-barreled ion-selective microelectrodes, and in vitro [isolated single flexor digitorum brevis fibers] using fluorescent ROS sensor CM-H2DCFDA in young (3 months of age), middle-aged (12 months of age), and aged (24 months of age) mice. We found an age-related increase in [Ca2+]i from 121 ± 4 nM in young muscle cells which rose to 255 ± 36 nM in middle-aged and to 409 ± 25 nM in aged cells. [Na+]i also showed an age-dependent elevation, increasing from 8 ± 0.5 mM in young muscle fibers, to 12 ± 1 mM in middle-aged and to 17 ± 1 mM in old muscle fibers. Using the fluorescent ROS sensor CM-H2DCFDA we found that these increases in intracellular cation concentrations were associated with significantly increased basal ROS production as demonstrated by age related increases in the rate of dichlorodihydrofluorescein fluorescence. To determine is this could be modified by reducing ROS and/or blocking sarcolemmal Ca2+ influx we administered flufenamic acid (FFA), a non-steroidal anti-inflammatory drug which is also a non-selective blocker of the transient receptor potential canonical channels (TRPCs), for 4 weeks to determine if this would have a beneficial effect. FFA treatment reduced both basal ROS production and muscle [Ca2+]i and [Na+]i in middle-aged and aged muscle fibers compared to fibers and muscles of untreated 12 and 24-months old mice. [Ca2+]i was reduced to 134 ± 8 nM in middle-aged muscle and to 246 ± 40 nM in muscle from aged mice. Likewise [Na+]i was reduced to 9 ± 0.7 mM in middle-aged muscles and to 13 ± 1 mM in muscle from aged mice. FFA treatment also reduced age associated increases in plasma interleukin 6 and tumor necrosis factor-alpha (TNF-α) concentrations which were elevated in 12 and 24-months old mice compared to young mice and decreased age-related muscle damage as indicated by a reduction in serum creatine kinase (CK) activity. Our data provides a direct demonstration that normal aging is associated with a significant elevation [Ca2+]i, [Na+]i, and intracellular ROS production in skeletal muscle fibers. Furthermore, the fact that FFA reduced the intracellular [Ca2+], [Na+], and ROS production as well as the elevated IL6, TNF-α, and CK levels, led us to suggest that its pharmacological effect may be related to its action both as a TRPC channel blocker and as an anti-inflammatory.
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Affiliation(s)
- Alfredo Mijares
- Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Paul D Allen
- Malignant Hyperthermia Investigation Unit, St James' University Hospital, University of Leeds, Leeds, United Kingdom
| | - Jose R Lopez
- Department of Research, Mount Sinai Medical Center, Miami, FL, United states
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Knudsen JR, Steenberg DE, Hingst JR, Hodgson LR, Henriquez-Olguin C, Li Z, Kiens B, Richter EA, Wojtaszewski JFP, Verkade P, Jensen TE. Prior exercise in humans redistributes intramuscular GLUT4 and enhances insulin-stimulated sarcolemmal and endosomal GLUT4 translocation. Mol Metab 2020; 39:100998. [PMID: 32305516 PMCID: PMC7240215 DOI: 10.1016/j.molmet.2020.100998] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 04/14/2020] [Indexed: 12/30/2022] Open
Abstract
Objective Exercise is a cornerstone in the management of skeletal muscle insulin-resistance. A well-established benefit of a single bout of exercise is increased insulin sensitivity for hours post-exercise in the previously exercised musculature. Although rodent studies suggest that the insulin-sensitization phenomenon involves enhanced insulin-stimulated GLUT4 cell surface translocation and might involve intramuscular redistribution of GLUT4, the conservation to humans is unknown. Methods Healthy young males underwent an insulin-sensitizing one-legged kicking exercise bout for 1 h followed by fatigue bouts to exhaustion. Muscle biopsies were obtained 4 h post-exercise before and after a 2-hour hyperinsulinemic-euglycemic clamp. Results A detailed microscopy-based analysis of GLUT4 distribution within seven different myocellular compartments revealed that prior exercise increased GLUT4 localization in insulin-responsive storage vesicles and T-tubuli. Furthermore, insulin-stimulated GLUT4 localization was augmented at the sarcolemma and in the endosomal compartments. Conclusions An intracellular redistribution of GLUT4 post-exercise is proposed as a molecular mechanism contributing to the insulin-sensitizing effect of prior exercise in human skeletal muscle. Intramyocellular GLUT4 is redistributed 4 h after exercise in humans. GLUT4 content is increased in GLUT4 storage vesicles and T-tubuli post-exercise. Prior exercise + insulin increases sarcolemmal and endosomal GLUT4. GLUT4 redistribution may thus contribute to post-exercise muscle insulin-sensitization.
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Affiliation(s)
- Jonas R Knudsen
- Molecular Physiology Section, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Oe, Denmark; Laboratory of Microsystems 2, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne, Batiment BM, 1015, Lausanne, Switzerland
| | - Dorte E Steenberg
- Molecular Physiology Section, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Oe, Denmark
| | - Janne R Hingst
- Molecular Physiology Section, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Oe, Denmark
| | - Lorna R Hodgson
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD, Bristol, United Kingdom
| | - Carlos Henriquez-Olguin
- Molecular Physiology Section, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Oe, Denmark
| | - Zhencheng Li
- Molecular Physiology Section, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Oe, Denmark
| | - Bente Kiens
- Molecular Physiology Section, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Oe, Denmark
| | - Erik A Richter
- Molecular Physiology Section, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Oe, Denmark
| | - Jørgen F P Wojtaszewski
- Molecular Physiology Section, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Oe, Denmark
| | - Paul Verkade
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD, Bristol, United Kingdom
| | - Thomas E Jensen
- Molecular Physiology Section, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Oe, Denmark.
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7
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Molinaro P, Natale S, Serani A, Calabrese L, Secondo A, Tedeschi V, Valsecchi V, Pannaccione A, Scorziello A, Annunziato L. Genetically modified mice to unravel physiological and pathophysiological roles played by NCX isoforms. Cell Calcium 2020; 87:102189. [PMID: 32199207 DOI: 10.1016/j.ceca.2020.102189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/27/2020] [Accepted: 03/01/2020] [Indexed: 11/30/2022]
Abstract
Since the discovery of the three isoforms of the Na+/Ca2+ exchanger, NCX1, NCX2 and NCX3 in 1990s, many studies have been devoted to identifying their specific roles in different tissues under several physiological or pathophysiological conditions. In particular, several seminal experimental works laid the foundation for better understanding gene and protein structures, tissue distribution, and regulatory functions of each antiporter isoform. On the other hand, despite the efforts in the development of specific compounds selectively targeting NCX1, NCX2 or NCX3 to test their physiological or pathophysiological roles, several drawbacks hampered the achievement of these goals. In fact, at present no isoform-specific compounds have been yet identified. Moreover, these compounds, despite their potency, possess some nonspecific actions against other ion antiporters, ion channels, and channel receptors. As a result, it is difficult to discriminate direct effects of inhibition/activation of NCX isoforms from the inhibitory or stimulatory effects exerted on other antiporters, channels, receptors, or enzymes. To overcome these difficulties, some research groups used transgenic, knock-out and knock-in mice for NCX isoforms as the most straightforward and fruitful strategy to characterize the biological role exerted by each antiporter isoform. The present review will survey the techniques used to study the roles of NCXs and the current knowledge obtained from these genetic modified mice focusing on the advantages obtained with these strategies in understanding the contribution exerted by each isoform.
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Affiliation(s)
- Pasquale Molinaro
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, 80131, Naples, Italy.
| | - Silvia Natale
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, 80131, Naples, Italy
| | - Angelo Serani
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, 80131, Naples, Italy
| | - Lucrezia Calabrese
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, 80131, Naples, Italy
| | - Agnese Secondo
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, 80131, Naples, Italy
| | - Valentina Tedeschi
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, 80131, Naples, Italy
| | - Valeria Valsecchi
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, 80131, Naples, Italy
| | - Anna Pannaccione
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, 80131, Naples, Italy
| | - Antonella Scorziello
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, 80131, Naples, Italy
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Lariccia V, Amoroso S. Letter to the editor regarding the article by Chen et al. entitled "Protective effects of echinacoside against anoxia/reperfusion injury in H9c2 cells via up-regulating p-AKT and SLC8A3". Biomed Pharmacother 2018; 108:58-59. [PMID: 30216800 DOI: 10.1016/j.biopha.2018.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/04/2018] [Indexed: 11/30/2022] Open
Affiliation(s)
- Vincenzo Lariccia
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Via Tronto 10/A, 60126, Ancona, Italy.
| | - Salvatore Amoroso
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Via Tronto 10/A, 60126, Ancona, Italy.
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Nascimento AMD, Lima EMD, Brasil GA, Caliman IF, Silva JFD, Lemos VS, Andrade TUD, Bissoli NS. Serca2a and Na+/Ca2+ exchanger are involved in left ventricular function following cardiac remodelling of female rats treated with anabolic androgenic steroid. Toxicol Appl Pharmacol 2016; 301:22-30. [DOI: 10.1016/j.taap.2016.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 03/16/2016] [Accepted: 04/01/2016] [Indexed: 11/16/2022]
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Exercise improves endothelial function: a local analysis of production of nitric oxide and reactive oxygen species. Nitric Oxide 2015; 45:7-14. [PMID: 25619203 DOI: 10.1016/j.niox.2015.01.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 12/15/2014] [Accepted: 01/16/2015] [Indexed: 12/20/2022]
Abstract
This study aimed at investigating the acute effects of aerobic exercise on endothelium-dependent vasomotor function of rat aorta, as well as mechanisms involved in endothelial nitric oxide (NO) bioactivity. Wistar rats were assigned to either a resting control (C, n = 21) or acutely exercised (E, n = 21) groups (60 min, 55-60% of maximum speed). After exercise, thoracic aorta was excised and cut into rings. Two rings were promptly applied to evaluate vasomotor function and the rest of aorta was used for additional measurements. Acute exercise significantly improved maximum ACh-induced relaxation (C, 91.6 ± 1.2 vs. E, 102.4 ± 1.7%, p < 0.001) and sensitivity to ACh (C, -7.3 ± 0.06 vs. E, -7.3 ± 0.02 log M, p < 0.01), and was accompanied by significantly increases on serine1177 eNOS phosphorylation, reflecting its enhanced activation. However, acute exercise also enhanced both superoxide and hydrogen peroxide production, as assayed by dihydroethidium oxidation, lucigenin chemiluminescence and Amplex Red assays. We also provided evidence for Nox2 NADPH oxidase (Nox) activation through gp91dstat-mediated inhibition of superoxide signals. Enhanced arterial relaxations associated with acute exercise were nearly-completely prevented by catalase, suggesting a role for paracrine hydrogen peroxide. Despite increased detectable oxidant generation, cellular oxidative stress was not evident, as suggested by unaltered GSH:GSSG ratio and lipid hydroperoxides. Collectively, these results demonstrate that one bout of moderate aerobic exercise improves endothelial function by increasing NO bioavailability, while superoxide and hydrogen peroxide are generated in a controlled fashion.
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Towards Understanding the Role of the Na+-Ca2+ Exchanger Isoform 3. Rev Physiol Biochem Pharmacol 2015; 168:31-57. [DOI: 10.1007/112_2015_23] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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12
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Calderón JC, Bolaños P, Caputo C. Tetanic Ca2+ transient differences between slow- and fast-twitch mouse skeletal muscle fibres: a comprehensive experimental approach. J Muscle Res Cell Motil 2014; 35:279-93. [DOI: 10.1007/s10974-014-9388-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 09/03/2014] [Indexed: 12/17/2022]
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Liantonio A, Camerino GM, Scaramuzzi A, Cannone M, Pierno S, De Bellis M, Conte E, Fraysse B, Tricarico D, Conte Camerino D. Calcium homeostasis is altered in skeletal muscle of spontaneously hypertensive rats: cytofluorimetric and gene expression analysis. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2803-15. [PMID: 25084345 DOI: 10.1016/j.ajpath.2014.06.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 06/11/2014] [Accepted: 06/17/2014] [Indexed: 11/25/2022]
Abstract
Hypertension is often associated with skeletal muscle pathological conditions related to function and metabolism. The mechanisms underlying the development of these pathological conditions remain undefined. Because calcium homeostasis is a biomarker of muscle function, we assessed whether it is altered in hypertensive muscles. We measured resting intracellular calcium and store-operated calcium entry (SOCE) in fast- and slow-twitch muscle fibers from normotensive Wistar-Kyoto rats and spontaneously hypertensive rats (SHRs) by cytofluorimetric technique and determined the expression of SOCE gene machinery by real-time PCR. Hypertension caused a phenotype-dependent dysregulation of calcium homeostasis; the resting intracellular calcium of extensor digitorum longus and soleus muscles of SHRs were differently altered with respect to the related muscle of normotensive animals. In addition, soleus muscles of SHR showed reduced activity of the sarcoplasmic reticulum and decreased sarcolemmal calcium permeability at rest and after SOCE activation. Accordingly, we found an alteration of the expression levels of some SOCE components, such as stromal interaction molecule 1, calcium release-activated calcium modulator 1, and transient receptor potential canonical 1. The hypertension-induced alterations of calcium homeostasis in the soleus muscle of SHRs occurred with changes of some functional outcomes as excitability and resting chloride conductance. We provide suitable targets for therapeutic interventions aimed at counterbalancing muscle performance decline in hypertension, and propose the reported calcium-dependent parameters as indexes to predict how the antihypertensive drugs could influence muscle function.
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Affiliation(s)
- Antonella Liantonio
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Bari, Italy.
| | - Giulia M Camerino
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Bari, Italy
| | - Antonia Scaramuzzi
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Bari, Italy
| | - Maria Cannone
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Bari, Italy
| | - Sabata Pierno
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Bari, Italy
| | - Michela De Bellis
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Bari, Italy
| | - Elena Conte
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Bari, Italy
| | - Bodvael Fraysse
- INRA UMR703, LUNAM Université, Oniris, École Nationale Vétérinaire, Agro-Alimentaire et de l'Alimentation Nantes-Atlantique, Nantes, France
| | - Domenico Tricarico
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Bari, Italy
| | - Diana Conte Camerino
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Bari, Italy
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14
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Altamirano F, Eltit JM, Robin G, Linares N, Ding X, Pessah IN, Allen PD, López JR. Ca2+ influx via the Na+/Ca2+ exchanger is enhanced in malignant hyperthermia skeletal muscle. J Biol Chem 2014; 289:19180-90. [PMID: 24847052 DOI: 10.1074/jbc.m114.550764] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Malignant hyperthermia (MH) is potentially fatal pharmacogenetic disorder of skeletal muscle caused by intracellular Ca(2+) dysregulation. NCX is a bidirectional transporter that effluxes (forward mode) or influxes (reverse mode) Ca(2+) depending on cellular activity. Resting intracellular calcium ([Ca(2+)]r) and sodium ([Na(+)]r) concentrations are elevated in MH susceptible (MHS) swine and murine muscles compared with their normal (MHN) counterparts, although the contribution of NCX is unclear. Lowering [Na(+)]e elevates [Ca(2+)]r in both MHN and MHS swine muscle fibers and it is prevented by removal of extracellular Ca(2+) or reduced by t-tubule disruption, in both genotypes. KB-R7943, a nonselective NCX3 blocker, reduced [Ca(2+)]r in both swine and murine MHN and MHS muscle fibers at rest and decreased the magnitude of the elevation of [Ca(2+)]r observed in MHS fibers after exposure to halothane. YM-244769, a high affinity reverse mode NCX3 blocker, reduces [Ca(2+)]r in MHS muscle fibers and decreases the amplitude of [Ca(2+)]r rise triggered by halothane, but had no effect on [Ca(2+)]r in MHN muscle. In addition, YM-244769 reduced the peak and area under the curve of the Ca(2+) transient elicited by high [K(+)]e and increased its rate of decay in MHS muscle fibers. siRNA knockdown of NCX3 in MHS myotubes reduced [Ca(2+)]r and the Ca(2+) transient area induced by high [K(+)]e. These results demonstrate a functional NCX3 in skeletal muscle whose activity is enhanced in MHS. Moreover reverse mode NCX3 contributes to the Ca(2+) transients associated with K(+)-induced depolarization and the halothane-triggered MH episode in MHS muscle fibers.
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Affiliation(s)
- Francisco Altamirano
- From the Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616
| | - José M Eltit
- the Department of Anesthesiology Perioperative and Pain Medicine, Brigham & Women's Hospital, Boston, Massachusetts 02115, and the Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Gaëlle Robin
- From the Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616
| | - Nancy Linares
- the Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas 1020-A, Venezuela
| | - Xudong Ding
- the Department of Anesthesiology Perioperative and Pain Medicine, Brigham & Women's Hospital, Boston, Massachusetts 02115, and
| | - Isaac N Pessah
- From the Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616
| | - Paul D Allen
- From the Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616, the Department of Anesthesiology Perioperative and Pain Medicine, Brigham & Women's Hospital, Boston, Massachusetts 02115, and
| | - José R López
- From the Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616, the Department of Anesthesiology Perioperative and Pain Medicine, Brigham & Women's Hospital, Boston, Massachusetts 02115, and the Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas 1020-A, Venezuela,
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15
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Na+ dysregulation coupled with Ca2+ entry through NCX1 promotes muscular dystrophy in mice. Mol Cell Biol 2014; 34:1991-2002. [PMID: 24662047 DOI: 10.1128/mcb.00339-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Unregulated Ca(2+) entry is thought to underlie muscular dystrophy. Here, we generated skeletal-muscle-specific transgenic (TG) mice expressing the Na(+)-Ca(2+) exchanger 1 (NCX1) to model its identified augmentation during muscular dystrophy. The NCX1 transgene induced dystrophy-like disease in all hind-limb musculature, as well as exacerbated the muscle disease phenotypes in δ-sarcoglycan (Sgcd(-/-)), Dysf(-/-), and mdx mouse models of muscular dystrophy. Antithetically, muscle-specific deletion of the Slc8a1 (NCX1) gene diminished hind-limb pathology in Sgcd(-/-) mice. Measured increases in baseline Na(+) and Ca(2+) in dystrophic muscle fibers of the hind-limb musculature predicts a net Ca(2+) influx state due to reverse-mode operation of NCX1, which mediates disease. However, the opposite effect is observed in the diaphragm, where NCX1 overexpression mildly protects from dystrophic disease through a predicted enhancement in forward-mode NCX1 operation that reduces Ca(2+) levels. Indeed, Atp1a2(+/-) (encoding Na(+)-K(+) ATPase α2) mice, which have reduced Na(+) clearance rates that would favor NCX1 reverse-mode operation, showed exacerbated disease in the hind limbs of NCX1 TG mice, similar to treatment with the Na(+)-K(+) ATPase inhibitor digoxin. Treatment of Sgcd(-/-) mice with ranolazine, a broadly acting Na(+) channel inhibitor that should increase NCX1 forward-mode operation, reduced muscular pathology.
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16
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Calderón JC, Bolaños P, Caputo C. The excitation-contraction coupling mechanism in skeletal muscle. Biophys Rev 2014; 6:133-160. [PMID: 28509964 PMCID: PMC5425715 DOI: 10.1007/s12551-013-0135-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 12/06/2013] [Indexed: 12/27/2022] Open
Abstract
First coined by Alexander Sandow in 1952, the term excitation-contraction coupling (ECC) describes the rapid communication between electrical events occurring in the plasma membrane of skeletal muscle fibres and Ca2+ release from the SR, which leads to contraction. The sequence of events in twitch skeletal muscle involves: (1) initiation and propagation of an action potential along the plasma membrane, (2) spread of the potential throughout the transverse tubule system (T-tubule system), (3) dihydropyridine receptors (DHPR)-mediated detection of changes in membrane potential, (4) allosteric interaction between DHPR and sarcoplasmic reticulum (SR) ryanodine receptors (RyR), (5) release of Ca2+ from the SR and transient increase of Ca2+ concentration in the myoplasm, (6) activation of the myoplasmic Ca2+ buffering system and the contractile apparatus, followed by (7) Ca2+ disappearance from the myoplasm mediated mainly by its reuptake by the SR through the SR Ca2+ adenosine triphosphatase (SERCA), and under several conditions movement to the mitochondria and extrusion by the Na+/Ca2+ exchanger (NCX). In this text, we review the basics of ECC in skeletal muscle and the techniques used to study it. Moreover, we highlight some recent advances and point out gaps in knowledge on particular issues related to ECC such as (1) DHPR-RyR molecular interaction, (2) differences regarding fibre types, (3) its alteration during muscle fatigue, (4) the role of mitochondria and store-operated Ca2+ entry in the general ECC sequence, (5) contractile potentiators, and (6) Ca2+ sparks.
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Affiliation(s)
- Juan C Calderón
- Physiology and Biochemistry Research Group-Physis, Department of Physiology and Biochemistry, Faculty of Medicine, University of Antioquia UdeA, Calle 70 No 52-21, Medellín, Colombia.
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela.
- Departamento de Fisiología y Bioquímica, Grupo de Investigación en Fisiología y Bioquímica-Physis, Facultad de Medicina, Universidad de Antioquia, Calle 70 No 52-21, Medellín, Colombia.
| | - Pura Bolaños
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
| | - Carlo Caputo
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
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17
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Engineered Human Muscle Tissue from Skeletal Muscle Derived Stem Cells and Induced Pluripotent Stem Cell Derived Cardiac Cells. ACTA ACUST UNITED AC 2013; 2013:198762. [PMID: 24734224 PMCID: PMC3984572 DOI: 10.1155/2013/198762] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
During development, cardiac and skeletal muscle share major transcription factors and sarcomere proteins which were generally regarded as specific to either cardiac or skeletal muscle but not both in terminally differentiated adult cardiac or skeletal muscle. Here, we investigated whether artificial muscle constructed from human skeletal muscle derived stem cells (MDSCs) recapitulates developmental similarities between cardiac and skeletal muscle. We constructed 3-dimensional collagen-based engineered muscle tissue (EMT) using MDSCs (MDSC-EMT) and compared the biochemical and contractile properties with EMT using induced pluripotent stem (iPS) cell-derived cardiac cells (iPS-EMT). Both MDSC-EMT and iPS-EMT expressed cardiac specific troponins, fast skeletal muscle myosin heavy chain, and connexin-43 mimicking developing cardiac or skeletal muscle. At the transcriptional level, MDSC-EMT and iPS-EMT upregulated both cardiac and skeletal muscle-specific genes and expressed Nkx2.5 and Myo-D proteins. MDSC-EMT displayed intracellular calcium ion transients and responses to isoproterenol. Contractile force measurements of MDSC-EMT demonstrated functional properties of immature cardiac and skeletal muscle in both tissues. Results suggest that the EMT from MDSCs mimics developing cardiac and skeletal muscle and can serve as a useful in vitro functioning striated muscle model for investigation of stem cell differentiation and therapeutic options of MDSCs for cardiac repair.
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Khananshvili D. The SLC8 gene family of sodium-calcium exchangers (NCX) - structure, function, and regulation in health and disease. Mol Aspects Med 2013; 34:220-35. [PMID: 23506867 DOI: 10.1016/j.mam.2012.07.003] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Accepted: 03/08/2012] [Indexed: 01/12/2023]
Abstract
The SLC8 gene family encoding Na(+)/Ca(2+) exchangers (NCX) belongs to the CaCA (Ca(2+)/Cation Antiporter) superfamily. Three mammalian genes (SLC8A1, SLC8A2, and SLC8A3) and their splice variants are expressed in a tissue-specific manner to mediate Ca(2+)-fluxes across the cell-membrane and thus, significantly contribute to regulation of Ca(2+)-dependent events in many cell types. A long-wanted mitochondrial Na(+)/Ca(2+) exchanger has been recently identified as NCLX protein, representing a gene product of SLC8B1. Distinct NCX isoform/splice variants contribute to excitation-contraction coupling, long-term potentiation of the brain and learning, blood pressure regulation, immune response, neurotransmitter and insulin secretion, mitochondrial bioenergetics, etc. Altered expression and regulation of NCX proteins contribute to distorted Ca(2+)-homeostasis in heart failure, arrhythmia, cerebral ischemia, hypertension, diabetes, renal Ca(2+) reabsorption, muscle dystrophy, etc. Recently, high-resolution X-ray structures of Ca(2+)-binding regulatory domains of eukaryotic NCX and of full-size prokaryotic NCX have become available and the dynamic properties have been analyzed by advanced biophysical approaches. Molecular silencing/overexpression of NCX in cellular systems and organ-specific KO mouse models provided useful information on the contribution of distinct NCX variants to cellular and systemic functions under various pathophysiological conditions. Selective inhibition or activation of predefined NCX variants in specific diseases might have clinical relevance, although this breakthrough has not yet been realized. A better understanding of the underlying molecular mechanisms as well as the development of in vitro procedures for high-throughput screening of "drug-like" compounds may lead to selective pharmacological targeting of NCX variants.
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Affiliation(s)
- Daniel Khananshvili
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel.
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19
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Mitogen-activated protein kinase-activated protein kinases 2 and 3 regulate SERCA2a expression and fiber type composition to modulate skeletal muscle and cardiomyocyte function. Mol Cell Biol 2013; 33:2586-602. [PMID: 23608535 DOI: 10.1128/mcb.01692-12] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The mitogen-activated protein kinase (MAPK)-activated protein kinases 2 and 3 (MK2/3) represent protein kinases downstream of the p38 MAPK. Using MK2/3 double-knockout (MK2/3(-/-)) mice, we analyzed the role of MK2/3 in cross-striated muscle by transcriptome and proteome analyses and by histology. We demonstrated enhanced expression of the slow oxidative skeletal muscle myofiber gene program, including the peroxisome proliferator-activated receptor gamma (PPARγ) coactivator 1α (PGC-1α). Using reporter gene and electrophoretic gel mobility shift assays, we demonstrated that MK2 catalytic activity directly regulated the promoters of the fast fiber-specific myosin heavy-chain IId/x and the slow fiber-specific sarco/endoplasmic reticulum Ca(2+)-ATPase 2 (SERCA2) gene. Elevated SERCA2a gene expression caused by a decreased ratio of transcription factor Egr-1 to Sp1 was associated with accelerated relaxation and enhanced contractility in MK2/3(-/-) cardiomyocytes, concomitant with improved force parameters in MK2/3(-/-) soleus muscle. These results link MK2/3 to the regulation of calcium dynamics and identify enzymatic activity of MK2/3 as a critical factor for modulating cross-striated muscle function by generating a unique muscle phenotype exhibiting both reduced fatigability and enhanced force in MK2/3(-/-) mice. Hence, the p38-MK2/3 axis may represent a novel target for the design of therapeutic strategies for diseases related to fiber type changes or impaired SERCA2 function.
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20
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Tu J, Lu L, Cai W, Ballard HJ. cAMP/protein kinase A activates cystic fibrosis transmembrane conductance regulator for ATP release from rat skeletal muscle during low pH or contractions. PLoS One 2012; 7:e50157. [PMID: 23226244 PMCID: PMC3511434 DOI: 10.1371/journal.pone.0050157] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 10/22/2012] [Indexed: 11/18/2022] Open
Abstract
We have shown that cystic fibrosis transmembrane conductance regulator (CFTR) is involved in ATP release from skeletal muscle at low pH. These experiments investigate the signal transduction mechanism linking pH depression to CFTR activation and ATP release, and evaluate whether CFTR is involved in ATP release from contracting muscle. Lactic acid treatment elevated interstitial ATP of buffer-perfused muscle and extracellular ATP of L6 myocytes: this ATP release was abolished by the non-specific CFTR inhibitor, glibenclamide, or the specific CFTR inhibitor, CFTRinh-172, suggesting that CFTR was involved, and by inhibition of lactic acid entry to cells, indicating that intracellular pH depression was required. Muscle contractions significantly elevated interstitial ATP, but CFTRinh-172 abolished the increase. The cAMP/PKA pathway was involved in the signal transduction pathway for CFTR-regulated ATP release from muscle: forskolin increased CFTR phosphorylation and stimulated ATP release from muscle or myocytes; lactic acid increased intracellular cAMP, pCREB and PKA activity, whereas IBMX enhanced ATP release from myocytes. Inhibition of PKA with KT5720 abolished lactic-acid- or contraction-induced ATP release from muscle. Inhibition of either the Na+/H+-exchanger (NHE) with amiloride or the Na+/Ca2+-exchanger (NCX) with SN6 or KB-R7943 abolished lactic-acid- or contraction-induced release of ATP from muscle, suggesting that these exchange proteins may be involved in the activation of CFTR. Our data suggest that CFTR-regulated release contributes to ATP release from contracting muscle in vivo, and that cAMP and PKA are involved in the activation of CFTR during muscle contractions or acidosis; NHE and NCX may be involved in the signal transduction pathway.
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Affiliation(s)
- Jie Tu
- Department of Physiology, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, People's Republic of China
- Shenzhen Key Laboratory for Neuropsychiatric Modulation, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, People's Republic of China
| | - Lin Lu
- Department of Physiology, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, People's Republic of China
- Institute of Cardiovascular Science and Medicine, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, People's Republic of China
| | - Weisong Cai
- Department of Physiology, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, People's Republic of China
- Institute of Cardiovascular Science and Medicine, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, People's Republic of China
| | - Heather J. Ballard
- Department of Physiology, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, People's Republic of China
- Institute of Cardiovascular Science and Medicine, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, People's Republic of China
- * E-mail:
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21
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Bueno CR, Ferreira JCB, Pereira MG, Bacurau AVN, Brum PC. Aerobic exercise training improves skeletal muscle function and Ca2+ handling-related protein expression in sympathetic hyperactivity-induced heart failure. J Appl Physiol (1985) 2010; 109:702-9. [DOI: 10.1152/japplphysiol.00281.2010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The cellular mechanisms of positive effects associated with aerobic exercise training on overall intrinsic skeletal muscle changes in heart failure (HF) remain unclear. We investigated potential Ca2+ abnormalities in skeletal muscles comprising different fiber compositions and investigated whether aerobic exercise training would improve muscle function in a genetic model of sympathetic hyperactivity-induced HF. A cohort of male 5-mo-old wild-type (WT) and congenic α2A/α2C adrenoceptor knockout (ARKO) mice in a C57BL/6J genetic background were randomly assigned into untrained and trained groups. Exercise training consisted of a 8-wk running session of 60 min, 5 days/wk (from 5 to 7 mo of age). After completion of the exercise training protocol, exercise tolerance was determined by graded treadmill exercise test, muscle function test by Rotarod, ambulation and resistance to inclination tests, cardiac function by echocardiography, and Ca2+ handling-related protein expression by Western blot. α2A/α2CARKO mice displayed decreased ventricular function, exercise intolerance, and muscle weakness paralleled by decreased expression of sarcoplasmic Ca2+ release-related proteins [α1-, α2-, and β1-subunits of dihydropyridine receptor (DHPR) and ryanodine receptor (RyR)] and Ca2+ reuptake-related proteins [sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)1/2 and Na+/Ca2+ exchanger (NCX)] in soleus and plantaris. Aerobic exercise training significantly improved exercise tolerance and muscle function and reestablished the expression of proteins involved in sarcoplasmic Ca2+ handling toward WT levels. We provide evidence that Ca2+ handling-related protein expression is decreased in this HF model and that exercise training improves skeletal muscle function associated with changes in the net balance of skeletal muscle Ca2+ handling proteins.
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Affiliation(s)
- C. R. Bueno
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - J. C. B. Ferreira
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - M. G. Pereira
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - A. V. N. Bacurau
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - P. C. Brum
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
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Ferreira JCB, Bacurau AV, Bueno CR, Cunha TC, Tanaka LY, Jardim MA, Ramires PR, Brum PC. Aerobic exercise training improves Ca2+ handling and redox status of skeletal muscle in mice. Exp Biol Med (Maywood) 2010; 235:497-505. [DOI: 10.1258/ebm.2009.009165] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Exercise training is known to promote relevant changes in the properties of skeletal muscle contractility toward powerful fibers. However, there are few studies showing the effect of a well-established exercise training protocol on Ca2+ handling and redox status in skeletal muscles with different fiber-type compositions. We have previously standardized a valid and reliable protocol to improve endurance exercise capacity in mice based on maximal lactate steady-state workload (MLSSw). The aim of this study was to investigate the effect of exercise training, performed at MLSSw, on the skeletal muscle Ca2+ handling-related protein levels and cellular redox status in soleus and plantaris. Male C57BL/6J mice performed treadmill training at MLSSw over a period of eight weeks. Muscle fiber-typing was determined by myosin ATPase histochemistry, citrate synthase activity by spectrophotometric assay, Ca2+ handling-related protein levels by Western blot and reduced to oxidized glutathione ratio (GSH:GSSG) by high-performance liquid chromatography. Trained mice displayed higher running performance and citrate synthase activity compared with untrained mice. Improved running performance in trained mice was paralleled by fast-to-slow fiber-type shift and increased capillary density in both plantaris and soleus. Exercise training increased dihydropyridine receptor (DHPR) α2 subunit, ryanodine receptor and Na+/Ca2+ exchanger levels in plantaris and soleus. Moreover, exercise training elevated DHPR β1 subunit and sarcoplasmic reticulum Ca2+-ATPase (SERCA) 1 levels in plantaris and SERCA2 levels in soleus of trained mice. Skeletal muscle GSH content and GSH:GSSG ratio was increased in plantaris and soleus of trained mice. Taken together, our findings indicate that MLSSw exercise-induced better running performance is, in part, due to increased levels of proteins involved in skeletal muscle Ca2+ handling, whereas this response is partially dependent on specificity of skeletal muscle fiber-type composition. Finally, we demonstrated an augmented cellular redox status and GSH antioxidant capacity in trained mice.
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Affiliation(s)
- Julio C B Ferreira
- School of Physical Education and Sport, University of Sao Paulo (USP), São Paulo 05508-900, Brazil
| | - Aline V Bacurau
- School of Physical Education and Sport, University of Sao Paulo (USP), São Paulo 05508-900, Brazil
| | - Carlos R Bueno
- School of Physical Education and Sport, University of Sao Paulo (USP), São Paulo 05508-900, Brazil
| | - Telma C Cunha
- School of Physical Education and Sport, University of Sao Paulo (USP), São Paulo 05508-900, Brazil
| | - Leonardo Y Tanaka
- School of Physical Education and Sport, University of Sao Paulo (USP), São Paulo 05508-900, Brazil
| | - Maira A Jardim
- School of Physical Education and Sport, University of Sao Paulo (USP), São Paulo 05508-900, Brazil
| | - Paulo R Ramires
- School of Physical Education and Sport, University of Sao Paulo (USP), São Paulo 05508-900, Brazil
| | - Patricia C Brum
- School of Physical Education and Sport, University of Sao Paulo (USP), São Paulo 05508-900, Brazil
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Ca2+ regulation in the Na+/Ca2+ exchanger features a dual electrostatic switch mechanism. Proc Natl Acad Sci U S A 2009; 106:14333-8. [PMID: 19667209 DOI: 10.1073/pnas.0902171106] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Regulation of ion-transport in the Na(+)/Ca(2+) exchanger (NCX) occurs via its cytoplasmic Ca(2+)-binding domains, CBD1 and CBD2. Here, we present a mechanism for NCX activation and inactivation based on data obtained using NMR, isothermal titration calorimetry (ITC) and small-angle X-ray scattering (SAXS). We initially determined the structure of the Ca(2+)-free form of CBD2-AD and the structure of CBD2-BD that represent the two major splice variant classes in NCX1. Although the apo-form of CBD2-AD displays partially disordered Ca(2+)-binding sites, those of CBD2-BD are entirely unstructured even in an excess of Ca(2+). Striking differences in the electrostatic potential between the Ca(2+)-bound and -free forms strongly suggest that Ca(2+)-binding sites in CBD1 and CBD2 form electrostatic switches analogous to C(2)-domains. SAXS analysis of a construct containing CBD1 and CBD2 reveals a conformational change mediated by Ca(2+)-binding to CBD1. We propose that the electrostatic switch in CBD1 and the associated conformational change are necessary for exchanger activation. The response of the CBD1 switch to intracellular Ca(2+) is influenced by the closely located cassette exons. We further propose that Ca(2+)-binding to CBD2 induces a second electrostatic switch, required to alleviate Na(+)-dependent inactivation of Na(+)/Ca(2+) exchange. In contrast to CBD1, the electrostatic switch in CBD2 is isoform- and splice variant-specific and allows for tailored exchange activities.
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Barrientos G, Bose DD, Feng W, Padilla I, Pessah IN. The Na+/Ca2+ exchange inhibitor 2-(2-(4-(4-nitrobenzyloxy)phenyl)ethyl)isothiourea methanesulfonate (KB-R7943) also blocks ryanodine receptors type 1 (RyR1) and type 2 (RyR2) channels. Mol Pharmacol 2009; 76:560-8. [PMID: 19509218 DOI: 10.1124/mol.109.057265] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Na(+)/Ca(2+) exchanger (NCX) is a plasma membrane transporter that moves Ca(2+) in or out of the cell, depending on membrane potential and transmembrane ion gradients. NCX is the main pathway for Ca(2+) extrusion from excitable cells. NCX inhibitors can ameliorate cardiac ischemia-reperfusion injury and promote high-frequency fatigue of skeletal muscle, purportedly by inhibiting the Ca(2+) inward mode of NCX. Here we tested two known NCX inhibitors, 2-(2-(4-(4-nitrobenzyloxy)phenyl)ethyl)-isothiourea methanesulfonate (KB-R7943) and the structurally related 2-[[4-[(4-Nitrophenyl)methoxy]phenyl]methyl]-4-thiazoli dinecarboxylic acid ethyl ester (SN-6), for their influence on electrically or caffeine-evoked Ca(2+) transients in adult dissociated flexor digitorum brevis (FDB) skeletal muscle fibers and human embryonic kidney (HEK) 293 cells that have stable expression of type 1 ryanodine receptor (RyR1). KB-R7943 (< or = 10 microM) reversibly attenuates electrically evoked Ca(2+) transients in FDB and caffeine-induced Ca(2+) release in HEK 293, whereas the structurally related NCX inhibitor SN-6 does not, suggesting that KB-R7943 directly inhibits RyR1. In support of this interpretation, KB-R7943 inhibits high-affinity binding of [(3)H]ryanodine to RyR1 (IC(50) = 5.1 +/- 0.9 microM) and the cardiac isoform RyR2 (IC(50) = 13.4 +/- 1.8 microM). KB-R7943 interfered with the gating of reconstituted RyR1 and RyR2 channels, reducing open probability (P(o)), shortening mean open time, and prolonging mean closed time. KB-R7943 was more effective at blocking RyR1 with cytoplasmic conditions favoring high P(o) compared with those favoring low P(o). SN-6 has negligible activity toward altering [(3)H]ryanodine binding of RyR1 and RyR2. Our results identify that KB-R7943 is a reversible, activity-dependent blocker of the two most broadly expressed RyR channel isoforms and contributes to its pharmacological and therapeutic activities.
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Affiliation(s)
- Genaro Barrientos
- Department of Molecular Biosciences, School of Veterinary Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
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25
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Germinario E, Esposito A, Midrio M, Peron S, Palade PT, Betto R, Danieli-Betto D. High-frequency fatigue of skeletal muscle: role of extracellular Ca(2+). Eur J Appl Physiol 2008; 104:445-53. [PMID: 18560877 DOI: 10.1007/s00421-008-0796-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2008] [Indexed: 10/21/2022]
Abstract
The present study evaluated whether Ca(2+) entry operates during fatigue of skeletal muscle. The involvement of different skeletal muscle membrane calcium channels and of the Na(+)/Ca(2+) exchanger (NCX) has been examined. The decline of force was analysed in vitro in mouse soleus and EDL muscles submitted to 60 and 110 Hz continuous stimulation, respectively. Stimulation with this high-frequency fatigue (HFF) protocol, in Ca(2+)-free conditions, caused in soleus muscle a dramatic increase of fatigue, while in the presence of high Ca(2+) fatigue was reduced. In EDL muscle, HFF was not affected by external Ca(2+) levels either way, suggesting that external Ca(2+) plays a general protective role only in soleus. Calciseptine, a specific antagonist of the cardiac isoform (alpha1C) of the dihydropyridine receptor, gadolinium, a blocker of both stretch-activated and store-operated Ca(2+) channels, as well as inhibitors of P2X receptors did not affect the development of HFF. Conversely, the Ca(2+) ionophore A23187 increased the protective action of extracellular Ca(2+). KB-R7943, a selective inhibitor of the reverse mode of NCX, produced an effect similar to that of Ca(2+)-free solution. These results indicate that a transmembrane Ca(2+) influx, mainly through NCX, may play a protective role during HFF development in soleus muscle.
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Affiliation(s)
- Elena Germinario
- Department of Human Anatomy and Physiology, University of Padova, Via Marzolo 3, 35131 Padova, Italy
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Goodman CA, Blazev R, Kemp J, Stephenson GMM. E–C coupling and contractile characteristics of mechanically skinned single fibres from young rats during rapid growth and maturation. Pflugers Arch 2008; 456:1217-28. [DOI: 10.1007/s00424-008-0474-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2007] [Accepted: 02/08/2008] [Indexed: 11/29/2022]
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27
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Abstract
The sodium-calcium exchanger (NCX) of plasma membrane is expressed in any animal cell. The specific role of its three isoforms (NCX1-3) is not yet established. Their levels vary considerably during murine postnatal development. In particular, in skeletal muscle, NCX1 expression decreases gradually upon aging while reciprocal changes take place for NCX3. NCX2 expression is restricted to brain and smooth muscles. The data on SDS-gel mobility shifts indicate that all three isoforms undergo Ca2+-dependent conformational changes, and that an exchanger regulatory Ca2+-binding domain interacts directly with mutually exclusive exons A and B inducing two different NCX1 conformations.
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Affiliation(s)
- Dmitri O Levitsky
- Université de Nantes, CNRS UMR 6204, Biotechnologie, Biocatalyse et Biorégulation, Faculté des Sciences et des Techniques, 44322 Nantes Cedex 3, France.
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Jurkat-Rott K, Fauler M, Lehmann-Horn F. Ion channels and ion transporters of the transverse tubular system of skeletal muscle. J Muscle Res Cell Motil 2006; 27:275-90. [PMID: 16933023 DOI: 10.1007/s10974-006-9088-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Accepted: 07/05/2006] [Indexed: 11/27/2022]
Abstract
This review focuses on the electrical properties of the transverse (T) tubular membrane of skeletal muscle, with reference to the contribution of the T-tubular system (TTS) to the surface action potential, the radial spread of excitation and its role in excitation-contraction coupling. Particularly, the most important ion channels and ion transporters that enable proper depolarization and repolarization of the T-tubular membrane are described. Since propagation of excitation along the TTS into the depth of the fibers is a delicate balance between excitatory and inhibitory currents, the composition of channels and transporters is specific to the TTS and different from the surface membrane. The TTS normally enables the radial spread of excitation and the signal transfer to the sarcoplasmic reticulum to release calcium that activates the contractile apparatus. However, due to its structure, even slight shifts of ions may alter its volume, Nernstian potentials, ion permeabilities, and consequently T-tubular membrane potential and excitability.
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29
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Pulina MV, Rizzuto R, Brini M, Carafoli E. Inhibitory interaction of the plasma membrane Na+/Ca2+ exchangers with the 14-3-3 proteins. J Biol Chem 2006; 281:19645-54. [PMID: 16679322 DOI: 10.1074/jbc.m602033200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The three Na+/Ca2+ exchanger isoforms, NCX1, NCX2, and NCX3, contain a large cytoplasmic loop that is responsible for the regulation of activity. We have used 347 residues of the loop of NCX2 as the bait in a yeast two-hybrid approach to identify proteins that could interact with the exchanger and regulate its activity. Screening of a human brain cDNA library identified the epsilon and zeta isoforms of the 14-3-3 protein family as interacting partners of the exchanger. The interaction was confirmed by immunoprecipitation and in vitro binding experiments. The effect of the interaction on the homeostasis of Ca2+ was investigated by co-expressing NCX2 and 14-3-3epsilon in HeLa cells together with the recombinant Ca2+ probe aequorin; the ability of cells expressing both NCX2 and 14-3-3epsilon to dispose of a Ca2+ transient induced by an InsP3-producing agonist was substantially decreased, indicating a reduction of NCX2 activity. The 14-3-3epsilon protein also inhibited the NCX1 and NCX3 isoforms. In vitro binding experiments revealed that all three NCX isoforms interacted with multiple 14-3-3 isoforms. 14-3-3 was bound by both phosphorylated and nonphosphorylated NCX, but the phosphorylated form had much higher binding affinity.
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Affiliation(s)
- Maria V Pulina
- Venetian Institute of Molecular Medicine, and Department of Biochemistry, University of Padova, 35100 Padova, Italy
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30
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Willems MET, Stauber WT. Streptomycin and EDTA decrease the number of desmin-negative fibers following stretch injury. Muscle Nerve 2005; 32:310-5. [PMID: 15948207 DOI: 10.1002/mus.20370] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Streptomycin and ethylene diamine tetraacetic acid (EDTA) were used to examine the role of extracellular calcium in stretch-induced muscle injury. Streptomycin was injected in one group of rats, three times daily for 8 days (S, 300 mg.kg(-1).day(-1) intraperitoneally). In another group, EDTA was administered (150 mg.kg(-1) IP) 20 min before and 24 h after the injury protocol. Untreated rats (C) served as controls. Muscle injury was produced by 40 stretches of active dorsiflexor muscles by ankle rotation from 80 degrees to 130 degrees (velocity 1.75 rad.s(-1)). Ten minutes after the injury protocols, all animals lost the same amount of isometric force at both low and high stimulation frequencies (20 HZ; S, 56 +/- 6%; EDTA, 47 +/- 7%; C, 55 +/- 4%) and 120 HZ; S, 11 +/- 3%, EDTA, 13 +/- 3%; C, 11 +/- 3%). Tibialis anterior (TA) muscles were removed after 48 h for morphometric analysis. In both streptomycin-and EDTA-treated rats, the percent of injured (i.e., desmin-negative) myofibers in TA was reduced compared to untreated, injured muscles (S, 0.35 +/- 0.08%; EDTA, 0.64 +/- 0.19%; C, 1.81 +/- 0.43%). Thus, streptomycin and EDTA treatment did not alter the development of muscle weakness (i.e., isometric force deficit), but almost abolished the histopathologic changes. This study shows that the mechanisms for muscle weakness and histopathologic changes (inflammation) following repeated muscle strains can largely be dissociated from each other and helps explain why there is no correlation between isometric force deficits and the number of pathologic cells.
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Affiliation(s)
- Mark E T Willems
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, West Virginia 26506, USA
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31
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Sokolow S, Manto M, Gailly P, Molgó J, Vandebrouck C, Vanderwinden JM, Herchuelz A, Schurmans S. Impaired neuromuscular transmission and skeletal muscle fiber necrosis in mice lacking Na/Ca exchanger 3. J Clin Invest 2004; 113:265-73. [PMID: 14722618 PMCID: PMC310749 DOI: 10.1172/jci18688] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2003] [Accepted: 11/19/2003] [Indexed: 11/17/2022] Open
Abstract
We produced and analyzed mice deficient for Na/Ca exchanger 3 (NCX3), a protein that mediates cellular Ca(2+) efflux (forward mode) or Ca(2+) influx (reverse mode) and thus controls intracellular Ca(2+) concentration. NCX3-deficient mice (Ncx3(-/-)) present a skeletal muscle fiber necrosis and a defective neuromuscular transmission, reflecting the absence of NCX3 in the sarcolemma of the muscle fibers and at the neuromuscular junction. The defective neuromuscular transmission is characterized by the presence of electromyographic abnormalities, including low compound muscle action potential amplitude, a decremental response at low-frequency nerve stimulation, an incremental response, and a prominent postexercise facilitation at high-frequency nerve stimulation, as well as neuromuscular blocks. The analysis of quantal transmitter release in Ncx3(-/-) neuromuscular junctions revealed an important facilitation superimposed on the depression of synaptic responses and an elevated delayed release during high-frequency nerve stimulation. It is suggested that Ca(2+) entering nerve terminals is cleared relatively slowly in the absence of NCX3, thereby enhancing residual Ca(2+) and evoked and delayed quantal transmitter release during repetitive nerve stimulation. Our findings indicate that NCX3 plays an important role in vivo in the control of Ca(2+) concentrations in the skeletal muscle fibers and at the neuromuscular junction.
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Affiliation(s)
- Sophie Sokolow
- Institut de Recherches en Biologie Humaine et Moléculaire-Institut de Biologie et de Médecine Moléculaires, and Laboratory of Pharmacology and Therapeutics, Université Libre de Bruxelles, Gosselies, Belgium.
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32
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Kyllönen MS, Parkkila S, Rajaniemi H, Waheed A, Grubb JH, Shah GN, Sly WS, Kaunisto K. Localization of carbonic anhydrase XII to the basolateral membrane of H+-secreting cells of mouse and rat kidney. J Histochem Cytochem 2003; 51:1217-24. [PMID: 12923247 DOI: 10.1177/002215540305100912] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Membrane-associated carbonic anhydrase (CA) has a crucial role in renal HCO(3)(-) absorption. CA activity has been localized to both luminal and basolateral membranes of the tubule epithelial cells. CA XII is a transmembrane isoenzyme that has been demonstrated in the basolateral plasma membrane of human renal, intestinal, and reproductive epithelia. The present study was designed to demonstrate the distribution of CA XII expression in the rodent kidney. A new polyclonal antibody to recombinant mouse CA XII was used in both Western blotting and immunohistochemistry. Western blotting analysis revealed a 40-45-kD polypeptide in CA XII-expressing CHO cells and isolated membranes of mouse and rat kidney. Immunofluorescence staining localized CA XII in the basolateral plasma membranes of S1 and S2 proximal tubule segments. Abundant basolateral staining of CA XII was seen in a subpopulation of cells in both cortical and medullary collecting ducts. Double immunofluorescence staining identified these cells as H(+)-secreting type A intercalated cells. The localization of CA XII in the peritubular space of proximal tubules suggests that it may play a role in renal HCO(3)(-) absorption, whereas the function of CA XII in the type A intercalated cells needs further investigation.
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Affiliation(s)
- Matti S Kyllönen
- Departments of Anatomy and Cell Biology, University of Oulu, Oulu, Finland
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33
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Abstract
Electrical conductance is greatly altered in end-stage heart failure, but little is known about the underlying events. We therefore investigated the expression of genes coding for major inward and outward ion channels, calcium binding proteins, ion receptors, ion exchangers, calcium ATPases, and calcium/calmodulin-dependent protein kinases in explanted hearts (n=13) of patients diagnosed with end-stage heart failure. With the exception of Kv11.1 and Kir3.1 and when compared with healthy controls, major sodium, potassium, and calcium ion channels, ion transporters, and exchangers were significantly repressed, but expression of Kv7.1, HCN4, troponin C and I, SERCA1, and phospholamban was elevated. Hierarchical gene cluster analysis provided novel insight into regulated gene networks. Significant induction of the transcriptional repressor m-Bop and the translational repressor NAT1 coincided with repressed cardiac gene expression. The statistically significant negative correlation between repressors and ion channels points to a mechanism of disease. We observed coregulation of ion channels and the androgen receptor and propose a role for this receptor in ion channel regulation. Overall, the reversal of repressed ion channel gene expression in patients with implanted assist devices exemplifies the complex interactions between pressure load/stretch force and heart-specific gene expression.
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Affiliation(s)
- Jürgen Borlak
- Fraunhofer Institute of Toxicology and Experimental Medicine, Center for Drug Research and Medical Biotechnology, 30625 Hannover, Germany.
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34
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Papa M, Canitano A, Boscia F, Castaldo P, Sellitti S, Porzig H, Taglialatela M, Annunziato L. Differential expression of the Na+-Ca2+ exchanger transcripts and proteins in rat brain regions. J Comp Neurol 2003; 461:31-48. [PMID: 12722103 DOI: 10.1002/cne.10665] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In the central nervous system (CNS), the Na(+)-Ca(2+) exchanger plays a fundamental role in controlling the changes in the intracellular concentrations of Na(+) and Ca(2+) ions. These cations are known to regulate neurotransmitter release, cell migration and differentiation, gene expression, and neurodegenerative processes. In the present study, nonradioactive in situ hybridization and light immunohistochemistry were carried out to map the regional and cellular distribution for both transcripts and proteins encoded by the three known Na(+)-Ca(2+) exchanger genes NCX1, NCX2, and NCX3. NCX1 transcripts were particularly expressed in layers III-V of the motor cortex, in the thalamus, in CA3 and the dentate gyrus of the hippocampus, in several hypothalamic nuclei, and in the cerebellum. NCX2 transcripts were strongly expressed in all hippocampal subregions, in the striatum, and in the paraventricular thalamic nucleus. NCX3 mRNAs were mainly detected in the hippocampus, in the thalamus, in the amygdala, and in the cerebellum. Immunohistochemical analysis revealed that NCX1 protein was mainly expressed in the supragranular layers of the cerebral cortex, in the hippocampus, in the hypothalamus, in the substantia nigra and ventral tegmental area, and in the granular layer of the cerebellum. The NCX2 protein was predominantly expressed in the hippocampus, in the striatum, in the thalamus, and in the hypothalamus. The NCX3 protein was particularly found in the CA3 subregion, and in the oriens, radiatum, and lacunoso-moleculare layers of the hippocampus, in the ventral striatum, and in the cerebellar molecular layer. Collectively, these results suggest that the different Na(+)-Ca(2+) exchanger isoforms appear to be selectively expressed in several CNS regions where they might underlie different functional roles.
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Affiliation(s)
- Michele Papa
- Departments of Neuroscience and Anatomy, School of Medicine, University of Naples Federico II and 2nd University of Naples, Naples, Italy
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35
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Thurneysen T, Nicoll DA, Philipson KD, Porzig H. Sodium/calcium exchanger subtypes NCX1, NCX2 and NCX3 show cell-specific expression in rat hippocampus cultures. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2002; 107:145-56. [PMID: 12425943 DOI: 10.1016/s0169-328x(02)00461-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Na(+)/Ca(2+) exchange activity is known to be expressed throughout the brain in both glial and neuronal tissue. mRNA of all three major subtypes of the mammalian Na(+)/Ca(2+) exchanger protein (NCX1, NCX2, NCX3) has been detected in most brain areas, albeit at varying densities. [The term 'subtype' is used for exchangers that are products of different genes (NCX1, NCX2, NCX3); 'isoform' is used for splice variants of a single gene product]. However, for lack of subtype specific labels, the cellular expression pattern of this transport protein has remained largely unknown. We have now used three subtype-specific antibodies, two monoclonal and one polyclonal, to identify the cellular distribution of the exchanger subtypes in rat hippocampus cell cultures. Surprisingly, we found little overlap for the expression of this membrane protein in different cell types. NCX1 labeled mainly the membranes of neuronal cells and their associated dendritic network. It was found in nearly all neuronal cells of the population growing in culture. In cultures maintained for more than 3 weeks, NCX1 was increasingly detected in the membrane of glia cells. NCX2 immunoreactivity was predominantly localized in various types of glia cells. It was also detected in the membranes of a few neuronal cell bodies but never in the dendritic network. In addition to labeling membranes, the NCX2 antibody strongly cross-reacted with an unidentified glial fibrillar protein. NCX3 expression appeared very low in hippocampus cultures and was restricted to a small subpopulation of neuronal cells. It was never detected in glia cells. Our results provide novel information on the cell-specific expression of the three Na(+)/Ca(2+) exchanger subtypes (NCX1, NCX2 and NCX3) in mammalian brain. These data may reflect functional differences among the subtypes that are not obvious from studies in recombinant cell lines and hence, may help to understand the functional role of specific glia- or neuron-associated Ca(2+) transport systems.
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Affiliation(s)
- Thomas Thurneysen
- Pharmakologisches Institut der Universität Bern, Friedbühlstrasse 49, CH 3010, Bern, Switzerland
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36
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Polumuri SK, Ruknudin A, McCarthy MM, Perrot-Sinal TS, Schulze DH. Sodium-calcium exchanger NCX1, NCX2, and NCX3 transcripts in developing rat brain. Ann N Y Acad Sci 2002; 976:60-3. [PMID: 12502534 DOI: 10.1111/j.1749-6632.2002.tb04714.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S K Polumuri
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland 21201, USA.
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37
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Deval E, Levitsky DO, Marchand E, Cantereau A, Raymond G, Cognard C. Na(+)/Ca(2+) exchange in human myotubes: intracellular calcium rises in response to external sodium depletion are enhanced in DMD. Neuromuscul Disord 2002; 12:665-73. [PMID: 12207936 DOI: 10.1016/s0960-8966(02)00022-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study aims to investigate the sodium/calcium exchanger expression in human co-cultured skeletal muscle cells and to compare the effects of Na(+)/Ca(2+) exchange activity in normal and dystrophic (Duchenne's muscular dystrophy) human co-cultured myotubes. For this purpose, variations of intracellular calcium concentration ([Ca(2+)](int)) were monitored, as the variations of the fluorescence ratio of indo-1 probe, in response to external sodium depletion. External sodium withdrawal induced [Ca(2+)](int) rises within several seconds in both normal and Duchenne's muscular dystrophy myotubes. These Na(+)-free-induced [Ca(2+)](int) elevations were attributed to the reverse mode of the Na(+)/Ca(2+) exchange mechanism since the phenomenon was dependent on extracellular calcium concentration ([Ca(2+)](ext)), and since it was sensitive to external Ni(2+) ions. Amplitudes of Na(+)-free-induced [Ca(2+)](int) rises were significantly greater in Duchenne's muscular dystrophy cells than in normal ones. Such a difference disappeared when the sarcoplasmic reticulum was pharmacologically blocked, suggesting that the reverse mode of the Na(+)/Ca(2+) exchange mechanism was able to generate enhanced calcium-induced calcium-release in Duchenne's muscular dystrophy myotubes. Immunostaining images of Na(+)/Ca(2+) exchanger (NCX) isoforms, obtained by confocal microscopy, revealed the presence of NCX1 and NCX3 at the sarcolemmal level of both normal and Duchenne's muscular dystrophy myotubes. No differences were observed in the location of NCX isoforms expression between normal and Duchenne's muscular dystrophy co-cultured myotubes.
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Affiliation(s)
- Emmanuel Deval
- Laboratoire des Biomembranes et Signalisation Cellulaire, UMR CNRS 6558, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Cedex, Poitiers, France
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38
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Schwartz GJ, Tsuruoka S, Vijayakumar S, Petrovic S, Mian A, Al-Awqati Q. Acid incubation reverses the polarity of intercalated cell transporters, an effect mediated by hensin. J Clin Invest 2002. [DOI: 10.1172/jci0213292] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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39
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Deval E, Raymond G, Cognard C. Na+-Ca2+ exchange activity in rat skeletal myotubes: effect of lithium ions. Cell Calcium 2002; 31:37-44. [PMID: 11990298 DOI: 10.1054/ceca.2001.0254] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The whole-cell patch-clamp technique coupled with intracellular [Ca2+] measurements was used to investigate the sodium-calcium exchange mechanism in rat skeletal muscle cells in primary culture. Replacing external Na+ ions with Li+ or N-methyl-D-glucamine (NMDG+) ions generated outward currents which were correlated with significant increases of free cytosolic-calcium concentration. These results strongly argue for a functional Na+-Ca2+ exchange mechanism working in its reverse mode. Moreover, the outward currents were sensitive to the new compound KB-R7943 (10 microM), which has been shown to be a potent inhibitor of the sodium-calcium exchanger. Outward Na+-Ca2+ exchange current densities were reduced in the presence of external Li+ as compared to those measured in the presence of NMDG+. After replacing internal sodium by lithium ions, rapid changes of external lithium concentrations generated sarcolemmal currents which were accompanied by subsequent variations of intracellular calcium activity. The currents were dependent on extracellular Li+ with a half-maximal activation at 67 mM and a Hill coefficient of 2.9. This work shows that the Na+-Ca2+ exchanger is able to significantly influence the myoplasmic calcium concentration of cultured rat myotubes. On the other hand, our results suggest that Li+ ions may substitute Na+ ions to catalyse an electrogenic Li+/Ca2+ counter transport.
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Affiliation(s)
- E Deval
- Laboratoire des Biomembranes et Signalisation Cellulaire, UMR CNRS/Université de Poitiers, France
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