1
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A century of exercise physiology: key concepts in regulation of glycogen metabolism in skeletal muscle. Eur J Appl Physiol 2022; 122:1751-1772. [PMID: 35355125 PMCID: PMC9287217 DOI: 10.1007/s00421-022-04935-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/15/2022] [Indexed: 01/20/2023]
Abstract
Glycogen is a branched, glucose polymer and the storage form of glucose in cells. Glycogen has traditionally been viewed as a key substrate for muscle ATP production during conditions of high energy demand and considered to be limiting for work capacity and force generation under defined conditions. Glycogenolysis is catalyzed by phosphorylase, while glycogenesis is catalyzed by glycogen synthase. For many years, it was believed that a primer was required for de novo glycogen synthesis and the protein considered responsible for this process was ultimately discovered and named glycogenin. However, the subsequent observation of glycogen storage in the absence of functional glycogenin raises questions about the true role of the protein. In resting muscle, phosphorylase is generally considered to be present in two forms: non-phosphorylated and inactive (phosphorylase b) and phosphorylated and constitutively active (phosphorylase a). Initially, it was believed that activation of phosphorylase during intense muscle contraction was primarily accounted for by phosphorylation of phosphorylase b (activated by increases in AMP) to a, and that glycogen synthesis during recovery from exercise occurred solely through mechanisms controlled by glucose transport and glycogen synthase. However, it now appears that these views require modifications. Moreover, the traditional roles of glycogen in muscle function have been extended in recent years and in some instances, the original concepts have undergone revision. Thus, despite the extensive amount of knowledge accrued during the past 100 years, several critical questions remain regarding the regulation of glycogen metabolism and its role in living muscle.
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2
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Blackwood SJ, Jude B, Mader T, Lanner JT, Katz A. Role of nitration in control of phosphorylase and glycogenolysis in mouse skeletal muscle. Am J Physiol Endocrinol Metab 2021; 320:E691-E701. [PMID: 33554777 DOI: 10.1152/ajpendo.00506.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phosphorylase is one of the most carefully studied proteins in history, but knowledge of its regulation during intense muscle contraction is incomplete. Tyrosine nitration of purified preparations of skeletal muscle phosphorylase results in inactivation of the enzyme and this is prevented by antioxidants. Whether an altered redox state affects phosphorylase activity and glycogenolysis in contracting muscle is not known. Here, we investigate the role of the redox state in control of phosphorylase and glycogenolysis in isolated mouse fast-twitch (extensor digitorum longus, EDL) and slow-twitch (soleus) muscle preparations during repeated contractions. Exposure of crude muscle extracts to H2O2 had little effect on phosphorylase activity. However, exposure of extracts to peroxynitrite (ONOO-), a nitrating/oxidizing agent, resulted in complete inactivation of phosphorylase (half-maximal inhibition at ∼200 µM ONOO-), which was fully reversed by the presence of an ONOO- scavanger, dithiothreitol (DTT). Incubation of isolated muscles with ONOO- resulted in nitration of phosphorylase and marked inhibition of glycogenolysis during repeated contractions. ONOO- also resulted in large decreases in high-energy phosphates (ATP and phosphocreatine) in the rested state and following repeated contractions. These metabolic changes were associated with decreased force production during repeated contractions (to ∼60% of control). In contrast, repeated contractions did not result in nitration of phosphorylase, nor did DTT or the general antioxidant N-acetylcysteine alter glycogenolysis during repeated contractions. These findings demonstrate that ONOO- inhibits phosphorylase and glycogenolysis in living muscle under extreme conditions. However, nitration does not play a significant role in control of phosphorylase and glycogenolysis during repeated contractions.NEW & NOTEWORTHY Here we show that exogenous peroxynitrite results in nitration of phosphorylase as well as inhibition of glycogenolysis in isolated intact mouse skeletal muscle during short-term repeated contractions. However, repeated contractions in the absence of exogenous peroxynitrite do not result in nitration of phosphorylase or affect glycogenolysis, nor does the addition of antioxidants alter glycogenolysis during repeated contractions. Thus phosphorylase is not subject to redox control during repeated contractions.
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Affiliation(s)
- Sarah J Blackwood
- Åstrand Laboratory of Work Physiology, Swedish School of Sport and Health Sciences, GIH, Stockholm, Sweden
| | - Baptiste Jude
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Solna, Sweden
| | - Theresa Mader
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Solna, Sweden
| | - Johanna T Lanner
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Solna, Sweden
| | - Abram Katz
- Åstrand Laboratory of Work Physiology, Swedish School of Sport and Health Sciences, GIH, Stockholm, Sweden
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3
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Scaricamazza S, Salvatori I, Ferri A, Valle C. Skeletal Muscle in ALS: An Unappreciated Therapeutic Opportunity? Cells 2021; 10:525. [PMID: 33801336 PMCID: PMC8000428 DOI: 10.3390/cells10030525] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the selective degeneration of upper and lower motor neurons and by the progressive weakness and paralysis of voluntary muscles. Despite intense research efforts and numerous clinical trials, it is still an incurable disease. ALS had long been considered a pure motor neuron disease; however, recent studies have shown that motor neuron protection is not sufficient to prevent the course of the disease since the dismantlement of neuromuscular junctions occurs before motor neuron degeneration. Skeletal muscle alterations have been described in the early stages of the disease, and they seem to be mainly involved in the "dying back" phenomenon of motor neurons and metabolic dysfunctions. In recent years, skeletal muscles have been considered crucial not only for the etiology of ALS but also for its treatment. Here, we review clinical and preclinical studies that targeted skeletal muscles and discuss the different approaches, including pharmacological interventions, supplements or diets, genetic modifications, and training programs.
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Affiliation(s)
- Silvia Scaricamazza
- Fondazione Santa Lucia IRCCS, c/o CERC, 00143 Rome, Italy; (S.S.); (I.S.)
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Illari Salvatori
- Fondazione Santa Lucia IRCCS, c/o CERC, 00143 Rome, Italy; (S.S.); (I.S.)
- Department of Experimental Medicine, University of Rome “La Sapienza”, 00161 Rome, Italy
| | - Alberto Ferri
- Fondazione Santa Lucia IRCCS, c/o CERC, 00143 Rome, Italy; (S.S.); (I.S.)
- Institute of Translational Pharmacology, National Research Council, 00133 Rome, Italy
| | - Cristiana Valle
- Fondazione Santa Lucia IRCCS, c/o CERC, 00143 Rome, Italy; (S.S.); (I.S.)
- Institute of Translational Pharmacology, National Research Council, 00133 Rome, Italy
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4
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Durrant C, Fuehring JI, Willemetz A, Chrétien D, Sala G, Ghidoni R, Katz A, Rötig A, Thelestam M, Ermonval M, Moore SEH. Defects in Galactose Metabolism and Glycoconjugate Biosynthesis in a UDP-Glucose Pyrophosphorylase-Deficient Cell Line Are Reversed by Adding Galactose to the Growth Medium. Int J Mol Sci 2020; 21:ijms21062028. [PMID: 32188137 PMCID: PMC7139386 DOI: 10.3390/ijms21062028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 12/28/2022] Open
Abstract
UDP-glucose (UDP-Glc) is synthesized by UGP2-encoded UDP-Glc pyrophosphorylase (UGP) and is required for glycoconjugate biosynthesis and galactose metabolism because it is a uridyl donor for galactose-1-P (Gal1P) uridyltransferase. Chinese hamster lung fibroblasts harboring a hypomrphic UGP(G116D) variant display reduced UDP-Glc levels and cannot grow if galactose is the sole carbon source. Here, these cells were cultivated with glucose in either the absence or presence of galactose in order to investigate glycoconjugate biosynthesis and galactose metabolism. The UGP-deficient cells display < 5% control levels of UDP-Glc/UDP-Gal and > 100-fold reduction of [6-3H]galactose incorporation into UDP-[6-3H]galactose, as well as multiple deficits in glycoconjugate biosynthesis. Cultivation of these cells in the presence of galactose leads to partial restoration of UDP-Glc levels, galactose metabolism and glycoconjugate biosynthesis. The Vmax for recombinant human UGP(G116D) with Glc1P is 2000-fold less than that of the wild-type protein, and UGP(G116D) displayed a mildly elevated Km for Glc1P, but no activity of the mutant enzyme towards Gal1P was detectable. To conclude, although the mechanism behind UDP-Glc/Gal production in the UGP-deficient cells remains to be determined, the capacity of this cell line to change its glycosylation status as a function of extracellular galactose makes it a useful, reversible model with which to study different aspects of galactose metabolism and glycoconjugate biosynthesis.
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Affiliation(s)
- Christelle Durrant
- INSERM U1149, Université de Paris, 16 rue Henri Huchard, 75018 Paris, France; (C.D.); (A.W.)
| | - Jana I. Fuehring
- Institute for Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany;
| | - Alexandra Willemetz
- INSERM U1149, Université de Paris, 16 rue Henri Huchard, 75018 Paris, France; (C.D.); (A.W.)
| | - Dominique Chrétien
- UMR1163, Université Paris Decartes, Sorbonnes Paris Cité, Institut Imagine, 24 Boulevard du Montparnasse, 75015 Paris, France; (D.C.); (A.R.)
| | - Giusy Sala
- “Aldo Ravelli” Research Center and Department of Health Sciences, University of Milan, 20146 Milan, Italy; (G.S.); (R.G.)
| | - Riccardo Ghidoni
- “Aldo Ravelli” Research Center and Department of Health Sciences, University of Milan, 20146 Milan, Italy; (G.S.); (R.G.)
| | - Abram Katz
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden;
| | - Agnès Rötig
- UMR1163, Université Paris Decartes, Sorbonnes Paris Cité, Institut Imagine, 24 Boulevard du Montparnasse, 75015 Paris, France; (D.C.); (A.R.)
| | - Monica Thelestam
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden;
| | - Myriam Ermonval
- Institut Pasteur, Department of Virology, 25 rue du Dr. Roux, 75015 Paris, France;
| | - Stuart E. H. Moore
- INSERM U1149, Université de Paris, 16 rue Henri Huchard, 75018 Paris, France; (C.D.); (A.W.)
- Correspondence:
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5
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Blackwood SJ, Katz A. Isoproterenol enhances force production in mouse glycolytic and oxidative muscle via separate mechanisms. Pflugers Arch 2019; 471:1305-1316. [PMID: 31451903 PMCID: PMC6814637 DOI: 10.1007/s00424-019-02304-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 07/22/2019] [Accepted: 08/13/2019] [Indexed: 02/04/2023]
Abstract
Fight or flight is a biologic phenomenon that involves activation of β-adrenoceptors in skeletal muscle. However, how force generation is enhanced through adrenergic activation in different muscle types is not fully understood. We studied the effects of isoproterenol (ISO, β-receptor agonist) on force generation and energy metabolism in isolated mouse soleus (SOL, oxidative) and extensor digitorum longus (EDL, glycolytic) muscles. Muscles were stimulated with isometric tetanic contractions and analyzed for metabolites and phosphorylase activity. Under conditions of maximal force production, ISO enhanced force generation markedly more in SOL (22%) than in EDL (8%). Similarly, during a prolonged tetanic contraction (30 s for SOL and 10 s for EDL), ISO-enhanced the force × time integral more in SOL (25%) than in EDL (3%). ISO induced marked activation of phosphorylase in both muscles in the basal state, which was associated with glycogenolysis (less in SOL than in EDL), and in EDL only, a significant decrease (16%) in inorganic phosphate (Pi). ATP turnover during sustained contractions (1 s EDL, 5 s SOL) was not affected by ISO in EDL, but essentially doubled in SOL. Under conditions of maximal stimulation, ISO has a minor effect on force generation in EDL that is associated with a decrease in Pi, whereas ISO has a marked effect on force generation in SOL that is associated with an increase in ATP turnover. Thus, phosphorylase functions as a phosphate trap in ISO-mediated force enhancement in EDL and as a catalyzer of ATP supply in SOL.
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Affiliation(s)
- Sarah J Blackwood
- Åstrand Laboratory of Work Physiology, Swedish School of Sport and Health Sciences, GIH, Box 5626, S-114 86, Stockholm, Sweden
| | - Abram Katz
- Åstrand Laboratory of Work Physiology, Swedish School of Sport and Health Sciences, GIH, Box 5626, S-114 86, Stockholm, Sweden.
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6
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Blackwood SJ, Hanya E, Katz A. Effect of postexercise temperature elevation on postexercise glycogen metabolism of isolated mouse soleus muscle. J Appl Physiol (1985) 2019; 126:1103-1109. [PMID: 30730817 DOI: 10.1152/japplphysiol.01121.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of temperature elevation after intense repeated contractions on glycogen and energy metabolism as well as contractile function of isolated mouse soleus muscle (slow twitch, oxidative) were investigated. Muscles were stimulated electrically to perform repeated tetanic contractions for 10 min at 25°C, which reduced tetanic force by ~85% and glycogen by 50%. After 120-min recovery at 25°C glycogen was fully restored (~125% of basal), whereas after recovery at 35°C glycogen decreased further (~25% of basal). Glycogen synthase fractional activity averaged 31.8 ± 3.1% (baseline = 33.8 ± 3.4%) after 120-min recovery at 25°C but was increased after recovery at 35°C (63.8 ± 4.8%; P < 0.001 vs. 25°C). Phosphorylase fractional and total activities were not affected by the higher temperature. However, recovery at 35°C resulted in a significantly higher content of the phosphorylase substrate inorganic phosphate (~20%; P < 0.01 vs. 25°C). Finally, fatigue development during a subsequent bout of repeated contractions at 25°C was similar after 120-min recovery at 25°C and 35°C. These data demonstrate that after intense contractions elevated temperature inhibits glycogen accumulation, likely by increasing the availability of the phosphorylase substrate inorganic phosphate, but has no effect on fatigue development. Thus after heat exposure phosphorylase plays a significant role in glycogen accumulation, and glycogen does not limit muscle performance in isolated mouse soleus muscle after recovery from elevated temperature. NEW & NOTEWORTHY Whether elevated temperature affects glycogen biogenesis and contractile performance of isolated slow-twitch muscle is not known. Here we show that after a bout of repeated contractions in isolated mouse soleus muscle at 25°C, increasing muscle temperature during recovery to 35°C blocked glycogen accumulation compared with recovery at 25°C. Surprisingly, during a subsequent bout of repeated contractions at 25°C, the rate of fatigue was not different between groups after recovery at the two temperatures.
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Affiliation(s)
- Sarah J Blackwood
- Department of Physical Therapy, School of Health Sciences, Ariel University, Ariel, Israel
| | - Ester Hanya
- Department of Physical Therapy, School of Health Sciences, Ariel University, Ariel, Israel
| | - Abram Katz
- Department of Physical Therapy, School of Health Sciences, Ariel University, Ariel, Israel
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7
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Lavorato M, Loro E, Debattisti V, Khurana TS, Franzini-Armstrong C. Elongated mitochondrial constrictions and fission in muscle fatigue. J Cell Sci 2018; 131:jcs221028. [PMID: 30404834 PMCID: PMC6288074 DOI: 10.1242/jcs.221028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 10/30/2018] [Indexed: 12/24/2022] Open
Abstract
Mitochondria respond to stress and undergo fusion and fission at variable rates, depending on cell status. To understand mitochondrial behavior during muscle fatigue, we investigated mitochondrial ultrastructure and expression levels of a fission- and stress-related protein in fast-twitch muscle fibers of mice subjected to fatigue testing. Mice were subjected to running at increasing speed until exhaustion at 45 min-1 h. In further experiments, high-intensity muscle stimulation through the sciatic nerve simulated the forced treadmill exercise. We detected a rare phenotype characterized by elongated mitochondrial constrictions (EMCs) connecting two separate segments of the original organelles. EMCs are rare in resting muscles and their frequency increases, albeit still at low levels, in stimulated muscles. The constrictions are accompanied by elevated phosphorylation of Drp1 (Dnm1l) at Ser 616, indicating an increased translocation of Drp1 to the mitochondrial membrane. This is indicative of a mitochondrial stress response, perhaps leading to or facilitating a long-lasting fission event. A close apposition of sarcoplasmic reticulum (SR) to the constricted areas, detected using both transmission and scanning electron microscopy, is highly suggestive of SR involvement in inducing mitochondrial constrictions.
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Affiliation(s)
- Manuela Lavorato
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Children's Hospital of Philadelphia, PA 19104, USA
| | - Emanuele Loro
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Valentina Debattisti
- MitoCare Center, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Tejvir S Khurana
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Clara Franzini-Armstrong
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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8
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Blackwood SJ, Hanya E, Katz A. Heating after intense repeated contractions inhibits glycogen accumulation in mouse EDL muscle: role of phosphorylase in postexercise glycogen metabolism. Am J Physiol Cell Physiol 2018; 315:C706-C713. [PMID: 30156860 DOI: 10.1152/ajpcell.00315.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The effects of heating on glycogen synthesis (incorporation of [14C]glucose into glycogen) and accumulation after intense repeated contractions were investigated. Isolated mouse extensor digitorum longus muscle (type II) was stimulated electrically to perform intense tetanic contractions at 25°C. After 120 min recovery at 25°C, glycogen accumulated to almost 80% of basal, whereas after recovery at 35°C, glycogen remained low (~25% of basal). Glycogen synthesis averaged 0.97 ± 0.07 µmol·30 min-1·g wet wt-1 during recovery at 25°C and 1.48 ± 0.08 during recovery at 35°C ( P < 0.001). There were no differences in phosphorylase and glycogen synthase total activities nor in phosphorylase fractional activity, whereas glycogen synthase fractional activity was increased by ~50% after recovery at 35°C vs. 25°C. Inorganic phosphate (Pi, substrate for phosphorylase) was markedly increased (~300% of basal) following contraction but returned to control levels after 120 min recovery at 25°C. In contrast, Pi remained elevated after recovery at 35°C (>2-fold higher than recovery at 25°C). Estimates of glycogen breakdown indicated that phosphorylase activity (either via inhibition at 25°C or activation at 35°C) was responsible for ~60% of glycogen accumulation during recovery at 25°C and ~45% during recovery at 35°C. These data demonstrate that despite the enhancing effect of heating on glycogen synthesis during recovery from intense contractions, glycogen accumulation is inhibited owing to Pi-mediated activation of phosphorylase. Thus phosphorylase can play a quantitatively important role in glycogen biogenesis during recovery from repeated contractions in isolated type II muscle.
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Affiliation(s)
- Sarah J Blackwood
- Department of Physical Therapy, School of Health Sciences, Ariel University, Ariel, Israel
| | - Ester Hanya
- Department of Physical Therapy, School of Health Sciences, Ariel University, Ariel, Israel
| | - Abram Katz
- Department of Physical Therapy, School of Health Sciences, Ariel University, Ariel, Israel
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9
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Lopez RJ, Mosca B, Treves S, Maj M, Bergamelli L, Calderon JC, Bentzinger CF, Romanino K, Hall MN, Rüegg MA, Delbono O, Caputo C, Zorzato F. Raptor ablation in skeletal muscle decreases Cav1.1 expression and affects the function of the excitation-contraction coupling supramolecular complex. Biochem J 2015; 466:123-35. [PMID: 25431931 PMCID: PMC4843809 DOI: 10.1042/bj20140935] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The protein mammalian target of rapamycin (mTOR) is a serine/threonine kinase regulating a number of biochemical pathways controlling cell growth. mTOR exists in two complexes termed mTORC1 and mTORC2. Regulatory associated protein of mTOR (raptor) is associated with mTORC1 and is essential for its function. Ablation of raptor in skeletal muscle results in several phenotypic changes including decreased life expectancy, increased glycogen deposits and alterations of the twitch kinetics of slow fibres. In the present paper, we show that in muscle-specific raptor knockout (RamKO), the bulk of glycogen phosphorylase (GP) is mainly associated in its cAMP-non-stimulated form with sarcoplasmic reticulum (SR) membranes. In addition, 3[H]-ryanodine and 3[H]-PN200-110 equilibrium binding show a ryanodine to dihydropyridine receptors (DHPRs) ratio of 0.79 and 1.35 for wild-type (WT) and raptor KO skeletal muscle membranes respectively. Peak amplitude and time to peak of the global calcium transients evoked by supramaximal field stimulation were not different between WT and raptor KO. However, the increase in the voltage sensor-uncoupled RyRs leads to an increase of both frequency and mass of elementary calcium release events (ECRE) induced by hyper-osmotic shock in flexor digitorum brevis (FDB) fibres from raptor KO. The present study shows that the protein composition and function of the molecular machinery involved in skeletal muscle excitation-contraction (E-C) coupling is affected by mTORC1 signalling.
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Affiliation(s)
- Rubén J. Lopez
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Barbara Mosca
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | - Susan Treves
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | - Marcin Maj
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Leda Bergamelli
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | - Juan C. Calderon
- Laboratorio de Fisiología Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, 1020A Caracas, Venezuela
| | | | - Klaas Romanino
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | | | | | - Osvaldo Delbono
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, U.S.A
| | - Carlo Caputo
- Laboratorio de Fisiología Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, 1020A Caracas, Venezuela
| | - Francesco Zorzato
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
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10
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Katz A, Westerblad H. Regulation of glycogen breakdown and its consequences for skeletal muscle function after training. Mamm Genome 2014; 25:464-72. [PMID: 24777203 DOI: 10.1007/s00335-014-9519-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/02/2014] [Indexed: 02/06/2023]
Abstract
Repeated bouts of physical exercise, i.e., training, induce mitochondrial biogenesis and result in improved physical performance and attenuation of glycogen breakdown during submaximal exercise. It has been suggested that as a consequence of the increased mitochondrial volume, a smaller degree of metabolic stress (e.g., smaller increases in ADP and Pi) is required to maintain mitochondrial respiration in the trained state during exercise at the same absolute intensity. The lower degree of Pi accumulation is believed to account for the diminished glycogen breakdown, since Pi is a substrate for glycogen phosphorylase, the rate-limiting enzyme for glycogenolysis. However, in this review, we present an alternative explanation for the diminished glycogen breakdown. Thus, the lower degree of metabolic stress after training is also associated with smaller increases in AMP (free concentration during contraction at specific intracellular sites) and this results in less activation of phosphorylase b (the non-phosphorylated form of phosphorylase), resulting in diminished glycogen breakdown. Concomitantly, the smaller accumulation of Pi, which interferes with cross-bridge function and intracellular Ca(2+) handling, contributes to the increased fatigue resistance. The delay in glycogen depletion also contributes to enhanced performance during prolonged exercise by functioning as an energy reserve.
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Affiliation(s)
- Abram Katz
- School of Health Sciences, Ariel University, 40700, Ariel, Israel,
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11
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Nath AK, Roberts LD, Liu Y, Mahon SB, Kim S, Ryu JH, Werdich A, Januzzi JL, Boss GR, Rockwood GA, MacRae CA, Brenner M, Gerszten RE, Peterson RT. Chemical and metabolomic screens identify novel biomarkers and antidotes for cyanide exposure. FASEB J 2013; 27:1928-38. [PMID: 23345455 PMCID: PMC3633825 DOI: 10.1096/fj.12-225037] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 01/14/2013] [Indexed: 11/11/2022]
Abstract
Exposure to cyanide causes a spectrum of cardiac, neurological, and metabolic dysfunctions that can be fatal. Improved cyanide antidotes are needed, but the ideal biological pathways to target are not known. To understand better the metabolic effects of cyanide and to discover novel cyanide antidotes, we developed a zebrafish model of cyanide exposure and scaled it for high-throughput chemical screening. In a screen of 3120 small molecules, we discovered 4 novel antidotes that block cyanide toxicity. The most potent antidote was riboflavin. Metabolomic profiling of cyanide-treated zebrafish revealed changes in bile acid and purine metabolism, most notably by an increase in inosine levels. Riboflavin normalizes many of the cyanide-induced neurological and metabolic perturbations in zebrafish. The metabolic effects of cyanide observed in zebrafish were conserved in a rabbit model of cyanide toxicity. Further, humans treated with nitroprusside, a drug that releases nitric oxide and cyanide ions, display increased circulating bile acids and inosine. In summary, riboflavin may be a novel treatment for cyanide toxicity and prophylactic measure during nitroprusside treatment, inosine may serve as a biomarker of cyanide exposure, and metabolites in the bile acid and purine metabolism pathways may shed light on the pathways critical to reversing cyanide toxicity.
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Affiliation(s)
- Anjali K. Nath
- Cardiovascular Research Center and
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
- Broad Institute, Cambridge, MA, USA
| | - Lee D. Roberts
- Cardiovascular Research Center and
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
- Broad Institute, Cambridge, MA, USA
| | - Yan Liu
- Cardiovascular Research Center and
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
- Broad Institute, Cambridge, MA, USA
| | - Sari B. Mahon
- Pulmonary and Critical Care Medicine, University of California–Irvine Medical Center, Orange, California, USA
| | - Sonia Kim
- Cardiovascular Research Center and
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Justine H. Ryu
- Cardiovascular Research Center and
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Andreas Werdich
- Division of Cardiology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - James L. Januzzi
- Cardiovascular Research Center and
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Gerry R. Boss
- Department of Medicine, University of California–San Diego, La Jolla, California, USA; and
| | - Gary A. Rockwood
- Analytical Toxicology Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Aberdeen, Maryland, USA
| | - Calum A. MacRae
- Division of Cardiology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew Brenner
- Pulmonary and Critical Care Medicine, University of California–Irvine Medical Center, Orange, California, USA
| | - Robert E. Gerszten
- Cardiovascular Research Center and
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
- Broad Institute, Cambridge, MA, USA
| | - Randall T. Peterson
- Cardiovascular Research Center and
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
- Broad Institute, Cambridge, MA, USA
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Dzeja PP, Hoyer K, Tian R, Zhang S, Nemutlu E, Spindler M, Ingwall JS. Rearrangement of energetic and substrate utilization networks compensate for chronic myocardial creatine kinase deficiency. J Physiol 2011; 589:5193-211. [PMID: 21878522 DOI: 10.1113/jphysiol.2011.212829] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Plasticity of the cellular bioenergetic system is fundamental to every organ function, stress adaptation and disease tolerance. Here, remodelling of phosphotransfer and substrate utilization networks in response to chronic creatine kinase (CK) deficiency, a hallmark of cardiovascular disease, has been revealed in transgenic mouse models lacking either cytosolic M-CK (M-CK(-/-)) or both M-CK and sarcomeric mitochondrial CK (M-CK/ScCKmit(-/-)) isoforms. The dynamic metabolomic signatures of these adaptations have also been defined. Tracking perturbations in metabolic dynamics with (18)O and (13)C isotopes and (31)P NMR and mass spectrometry demonstrate that hearts lacking M-CK have lower phosphocreatine (PCr) turnover but increased glucose-6-phosphate (G-6-P) turnover, glucose utilization and inorganic phosphate compartmentation with normal ATP γ-phosphoryl dynamics. Hearts lacking both M-CK and sarcomeric mitochondrial CK have diminished PCr turnover, total phosphotransfer capacity and intracellular energetic communication but increased dynamics of β-phosphoryls of ADP/ATP, G-6-P and γ-/β-phosphoryls of GTP, indicating redistribution of flux through adenylate kinase (AK), glycolytic and guanine nucleotide phosphotransfer circuits. Higher glycolytic and mitochondrial capacities and increased glucose tolerance contributed to metabolic resilience of M-CK/ScCKmit(-/-) mice. Multivariate analysis revealed unique metabolomic signatures for M-CK(-/-) and M-CK/ScCKmit(-/-) hearts suggesting that rearrangements in phosphotransfer and substrate utilization networks provide compensation for genetic CK deficiency. This new information highlights the significance of integrated CK-, AK-, guanine nucleotide- and glycolytic enzyme-catalysed phosphotransfer networks in supporting the adaptivity and robustness of the cellular energetic system.
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Affiliation(s)
- Petras P Dzeja
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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13
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Skeletal muscle: Energy metabolism, fiber types, fatigue and adaptability. Exp Cell Res 2010; 316:3093-9. [DOI: 10.1016/j.yexcr.2010.05.019] [Citation(s) in RCA: 182] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 05/17/2010] [Accepted: 05/17/2010] [Indexed: 11/20/2022]
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Zhang SJ, Sandström ME, Aydin J, Westerblad H, Wieringa B, Katz A. Activation of glucose transport and AMP-activated protein kinase during muscle contraction in adenylate kinase-1 knockout mice. Acta Physiol (Oxf) 2008; 192:413-20. [PMID: 17973952 DOI: 10.1111/j.1748-1716.2007.01767.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM Recently it was reported that adenylate kinase-1 knockout mice (AK(-/-)) exhibit elevated rates of glucose uptake following repeated contractions and hypoxia, but the mechanism was not investigated. The purpose of the present study was to measure the changes in glucose transport and AMP-activated protein kinase (AMPK) phosphorylation/activity following repeated contractions in isolated muscles from AK(-/-) mice. METHODS Extensor digitorum longus muscles underwent an intense stimulation protocol that decreased force to less than 10% of initial by the end of 10 min. Glucose uptake was measured with 2-deoxy-D-[1,2-(3)H]glucose. RESULTS Muscle glucose uptake in the basal state was identical between control and AK(-/-) mice and increased twofold in both groups during contraction. The general antioxidant: N-acetylcysteine, decreased contraction-mediated glucose uptake by 30% in both groups. AMPK activity and phosphorylation were similar in the two groups in the basal state and, surprisingly, after contraction as well (approximately threefold increase). Both groups exhibited marked decreases in adenosine triphosphate following contraction (60-70% depletion), which coincided with stoichiometric increases in the content of inosine monophosphate, an indirect marker of AMP production. Adenylate kinase activity averaged 2081 +/- 106 micromol min(-1) (g dry wt)(-1) for control and 37 +/- 10 for AK(-/-) muscles; the activity in the AK(-/-) muscle is likely accounted for by isoforms other than AK1. CONCLUSION In conclusion, AK(-/-) mice have a normal capacity for contraction-mediated glucose uptake. This appears to occur via increases in AMP and reactive oxygen species that result in the activation of AMPK.
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Affiliation(s)
- S-J Zhang
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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15
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Abstract
Interest in the kinetics of glycogen phosphorylase has recently been renewed by the hypothesis of a glycogen shunt and by the potential of altering phosphorylase to treat type II diabetes. The wealth of data from studies of this enzyme in vitro and the need for a mathematical representation for use in the study of metabolic control systems make this enzyme an ideal subject for a mathematical model. We applied a two-part approach to the analysis of the kinetics of glycogen phosphorylase b (GPb). First, a continuous state model of enzyme-ligand interactions supported the view that two phosphates and four ATP or AMP molecules can bind to the enzyme, a result that agrees with spectroscopic and crystallographic studies. Second, using minimum error estimates from continuous state model fits to published data (that agreed well with reported error), we used a discrete state model of internal molecular events to show that GPb exists in three discrete states (two of which are inactive) and that state transitions are concerted. The results also show that under certain concentrations of substrate and effector, ATP can activate the enzyme, while under other conditions, it can competetively inhibit or noncompetitively inhibit the enzyme. This result is unexpected but is consistent with spectroscopic, crystallographic, and kinetic experiments and can explain several previously unexplained phenomena regarding GPb activity in vivo and in vitro.
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Affiliation(s)
- Sam Walcott
- Theoretical and Applied Mechanics, 212 Kimball Hall, Cornell University, Ithaca, New York 14853, USA.
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Zhang SJ, Andersson DC, Sandström ME, Westerblad H, Katz A. Cross bridges account for only 20% of total ATP consumption during submaximal isometric contraction in mouse fast-twitch skeletal muscle. Am J Physiol Cell Physiol 2006; 291:C147-54. [PMID: 16481370 DOI: 10.1152/ajpcell.00578.2005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is generally believed that cross bridges account for >50% of the total ATP consumed by skeletal muscle during contraction. We investigated the effect of N-benzyl-p-toluene sulfonamide (BTS), an inhibitor of myosin ATPase, on muscle force production and energy metabolism under near-physiological conditions (50-Hz stimulation frequency at 30 degrees C results in 35% of maximal force). Extensor digitorum longus muscles from mice were isolated and stimulated to perform continuous isometric tetanic contractions. Metabolites of energy metabolism were analyzed with fluorometric techniques. ATP turnover was estimated from the changes in phosphocreatine (PCr), ATP, and lactate (-2DeltaATP - DeltaPCr + [1.5Deltalactate]). During contractions (2-10 s), BTS decreased force production to approximately 5% of control. Under these conditions, BTS inhibited ATP turnover by only 18-25%. ATP turnover decreased markedly and similarly with and without BTS as the duration of contraction progressed. In conclusion, cross bridges (i.e., actomyosin ATPase) account for only a small fraction (approximately 20%) of the ATP consumption during contraction in mouse fast-twitch skeletal muscle under near-physiological conditions, suggesting that ion pumping is the major energy-consuming process.
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Affiliation(s)
- Shi-Jin Zhang
- Department of Physiology and Pharmacology, Karolinska Institutet, Von Eulers väg 8, 171 77 Stockholm, Sweden
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