1
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Elowe CR, Stager M, Gerson AR. Sarcolipin relates to fattening, but not sarco/endoplasmic reticulum Ca2+-ATPase uncoupling, in captive migratory gray catbirds. J Exp Biol 2024; 227:jeb246897. [PMID: 38044822 DOI: 10.1242/jeb.246897] [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: 10/17/2023] [Accepted: 11/24/2023] [Indexed: 12/05/2023]
Abstract
In order to complete their energetically demanding journeys, migratory birds undergo a suite of physiological changes to prepare for long-duration endurance flight, including hyperphagia, fat deposition, reliance on fat as a fuel source, and flight muscle hypertrophy. In mammalian muscle, SLN is a small regulatory protein which binds to sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and uncouples Ca2+ transport from ATP hydrolysis, increasing energy consumption, heat production, and cytosolic Ca2+ transients that signal for mitochondrial biogenesis, fatigue resistance and a shift to fatty acid oxidation. Using a photoperiod manipulation of captive gray catbirds (Dumetella carolinensis), we investigated whether SLN may play a role in coordinating the development of the migratory phenotype. In response to long-day photostimulation, catbirds demonstrated migratory restlessness and significant body fat stores, alongside higher SLN transcription while SERCA2 remained constant. SLN transcription was strongly correlated with h-FABP and PGC1α transcription, as well as fat mass. However, SLN was not significantly correlated with HOAD or CD36 transcripts or measurements of SERCA activity, SR membrane Ca2+ leak, Ca2+ uptake rates, pumping efficiency or mitochondrial biogenesis. Therefore, SLN may be involved in the process of storing fat and shifting to fat as a fuel, but the mechanism of its involvement remains unclear.
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Affiliation(s)
- Cory R Elowe
- Department of Biology, University of Massachusetts, 221 Morrill Science Center III, 611 North Pleasant Street, Amherst, MA 01003-9297, USA
- Organismic and Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, MA 01003-9316, USA
| | - Maria Stager
- Department of Biology, University of Massachusetts, 221 Morrill Science Center III, 611 North Pleasant Street, Amherst, MA 01003-9297, USA
- Organismic and Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, MA 01003-9316, USA
| | - Alexander R Gerson
- Department of Biology, University of Massachusetts, 221 Morrill Science Center III, 611 North Pleasant Street, Amherst, MA 01003-9297, USA
- Organismic and Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, MA 01003-9316, USA
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2
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Graber TG, Maroto R, Thompson JK, Widen SG, Man Z, Pajski ML, Rasmussen BB. Skeletal Muscle Transcriptome Alterations Related to Declining Physical Function in Older Mice. JOURNAL OF AGEING AND LONGEVITY 2023; 3:159-178. [PMID: 37876943 PMCID: PMC10597580 DOI: 10.3390/jal3020013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
One inevitable consequence of aging is the gradual deterioration of physical function and exercise capacity, driven in part by the adverse effect of age on muscle tissue. We hypothesized that relationships exist between age-related differentially expressed genes (DEGs) in skeletal muscle and age-associated declines in physical function and exercise capacity. Previously, male C57BL/6mice (6m, months old, 24m, and 28m) were tested for physical function using a composite scoring system (comprehensive functional assessment battery, CFAB) comprised of five well-validated tests of physical function. In this study, total RNA was isolated from tibialis anterior samples (n = 8) randomly selected from each age group in the parent study. Using Next Generation Sequencing RNAseq to determine DEGs during aging (6m vs. 28m, and 6m vs. 24m), we found a greater than five-fold increase in DEGs in 28m compared to the 24m. Furthermore, regression of the normalized expression of each DEG with the CFAB score of the corresponding mouse revealed many more DEGs strongly associated (R ≥ |0.70|) with functional status in the older mice. Gene ontology results indicate highly enriched axon guidance and acetyl choline receptor gene sets, suggesting that denervation/reinnervation flux might potentially play a critical role in functional decline. We conclude that specific age-related DEG patterns are associated with declines in physical function, and the data suggest accelerated aging occurring between 24 and 28 months.
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Affiliation(s)
- Ted G. Graber
- Department of Physical Therapy, East Carolina University, Greenville, NC 27834, USA
| | - Rosario Maroto
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Jill K. Thompson
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Steven G. Widen
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Zhaohui Man
- Bioinformatics and Analytics Research Collaborative, University of North Carolina-Chapel Hill, Chapel Hill, NC 27514, USA
| | - Megan L. Pajski
- Department of Physical Therapy, East Carolina University, Greenville, NC 27834, USA
| | - Blake B. Rasmussen
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
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3
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Marchioretti C, Zanetti G, Pirazzini M, Gherardi G, Nogara L, Andreotti R, Martini P, Marcucci L, Canato M, Nath SR, Zuccaro E, Chivet M, Mammucari C, Pacifici M, Raffaello A, Rizzuto R, Mattarei A, Desbats MA, Salviati L, Megighian A, Sorarù G, Pegoraro E, Belluzzi E, Pozzuoli A, Biz C, Ruggieri P, Romualdi C, Lieberman AP, Babu GJ, Sandri M, Blaauw B, Basso M, Pennuto M. Defective excitation-contraction coupling and mitochondrial respiration precede mitochondrial Ca 2+ accumulation in spinobulbar muscular atrophy skeletal muscle. Nat Commun 2023; 14:602. [PMID: 36746942 PMCID: PMC9902403 DOI: 10.1038/s41467-023-36185-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 01/19/2023] [Indexed: 02/08/2023] Open
Abstract
Polyglutamine expansion in the androgen receptor (AR) causes spinobulbar muscular atrophy (SBMA). Skeletal muscle is a primary site of toxicity; however, the current understanding of the early pathological processes that occur and how they unfold during disease progression remains limited. Using transgenic and knock-in mice and patient-derived muscle biopsies, we show that SBMA mice in the presymptomatic stage develop a respiratory defect matching defective expression of genes involved in excitation-contraction coupling (ECC), altered contraction dynamics, and increased fatigue. These processes are followed by stimulus-dependent accumulation of calcium into mitochondria and structural disorganization of the muscle triads. Deregulation of expression of ECC genes is concomitant with sexual maturity and androgen raise in the serum. Consistent with the androgen-dependent nature of these alterations, surgical castration and AR silencing alleviate the early and late pathological processes. These observations show that ECC deregulation and defective mitochondrial respiration are early but reversible events followed by altered muscle force, calcium dyshomeostasis, and dismantling of triad structure.
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Affiliation(s)
- Caterina Marchioretti
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, 35100, Italy
- Padova Neuroscience Center (PNC), Padova, 35100, Italy
- Dulbecco Telethon Institute (DTI) at the Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123, Trento, Italy
| | - Giulia Zanetti
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
| | - Marco Pirazzini
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- CIR-Myo, Centro Interdipartimentale di Ricerca di Miologia, University of Padova, 35131, Padova, Italy
| | - Gaia Gherardi
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
| | - Leonardo Nogara
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, 35100, Italy
| | - Roberta Andreotti
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, 35100, Italy
- Padova Neuroscience Center (PNC), Padova, 35100, Italy
| | - Paolo Martini
- Department of Molecular and Translational Medicine, University of Brescia, 25121, Brescia, Italy
| | - Lorenzo Marcucci
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
| | - Marta Canato
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
| | - Samir R Nath
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Emanuela Zuccaro
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, 35100, Italy
- Padova Neuroscience Center (PNC), Padova, 35100, Italy
| | - Mathilde Chivet
- Dulbecco Telethon Institute (DTI) at the Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123, Trento, Italy
| | - Cristina Mammucari
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- CIR-Myo, Centro Interdipartimentale di Ricerca di Miologia, University of Padova, 35131, Padova, Italy
| | - Marco Pacifici
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
| | - Anna Raffaello
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- CIR-Myo, Centro Interdipartimentale di Ricerca di Miologia, University of Padova, 35131, Padova, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
| | - Andrea Mattarei
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131, Padova, Italy
| | - Maria A Desbats
- Clinical Genetics Unit, Department of Women and Children's Health, University of Padova, and Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Leonardo Salviati
- CIR-Myo, Centro Interdipartimentale di Ricerca di Miologia, University of Padova, 35131, Padova, Italy
- Clinical Genetics Unit, Department of Women and Children's Health, University of Padova, and Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Aram Megighian
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- Padova Neuroscience Center (PNC), Padova, 35100, Italy
| | - Gianni Sorarù
- Padova Neuroscience Center (PNC), Padova, 35100, Italy
- Department of Neuroscience (DNS), University of Padova, 35128, Padova, Italy
| | - Elena Pegoraro
- Department of Neuroscience (DNS), University of Padova, 35128, Padova, Italy
| | - Elisa Belluzzi
- Orthopedics and Orthopedic Oncology, Department of Surgery, Oncology, and Gastroenterology DiSCOG, University-Hospital of Padova, 35128, Padova, Italy
- Musculoskeletal Pathology and Oncology Laboratory, Department of Surgery, Oncology and Gastroenterology (DiSCOG), University of Padova, 35128, Padova, Italy
| | - Assunta Pozzuoli
- Orthopedics and Orthopedic Oncology, Department of Surgery, Oncology, and Gastroenterology DiSCOG, University-Hospital of Padova, 35128, Padova, Italy
- Musculoskeletal Pathology and Oncology Laboratory, Department of Surgery, Oncology and Gastroenterology (DiSCOG), University of Padova, 35128, Padova, Italy
| | - Carlo Biz
- Orthopedics and Orthopedic Oncology, Department of Surgery, Oncology, and Gastroenterology DiSCOG, University-Hospital of Padova, 35128, Padova, Italy
| | - Pietro Ruggieri
- Orthopedics and Orthopedic Oncology, Department of Surgery, Oncology, and Gastroenterology DiSCOG, University-Hospital of Padova, 35128, Padova, Italy
| | - Chiara Romualdi
- Department of Biology, University of Padova, Padova, 35100, Italy
| | - Andrew P Lieberman
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Gopal J Babu
- Department of Cell Biology and Molecular Medicine, Rutgers, New Jersey Medical School, Newark, NJ, 07103, USA
| | - Marco Sandri
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, 35100, Italy
| | - Bert Blaauw
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, 35100, Italy
| | - Manuela Basso
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123, Trento, Italy
| | - Maria Pennuto
- Department of Biomedical Sciences (DBS), University of Padova, 35131, Padova, Italy.
- Veneto Institute of Molecular Medicine (VIMM), Padova, 35100, Italy.
- Padova Neuroscience Center (PNC), Padova, 35100, Italy.
- Dulbecco Telethon Institute (DTI) at the Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123, Trento, Italy.
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4
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Baraldo M, Zorzato S, Dondjang AHT, Geremia A, Nogara L, Dumitras AG, Canato M, Marcucci L, Nolte H, Blaauw B. Inducible deletion of raptor and mTOR from adult skeletal muscle impairs muscle contractility and relaxation. J Physiol 2022; 600:5055-5075. [PMID: 36255030 DOI: 10.1113/jp283686] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/20/2022] [Indexed: 01/05/2023] Open
Abstract
Skeletal muscle weakness has been associated with different pathological conditions, including sarcopenia and muscular dystrophy, and is accompanied by altered mammalian target of rapamycin (mTOR) signalling. We wanted to elucidate the functional role of mTOR in muscle contractility. Most loss-of-function studies for mTOR signalling have used the drug rapamycin to inhibit some of the signalling downstream of mTOR. However, given that rapamycin does not inhibit all mTOR signalling completely, we generated a double knockout for mTOR and for the scaffold protein of mTORC1, raptor, in skeletal muscle. We found that double knockout in mice results in a more severe phenotype compared with deletion of raptor or mTOR alone. Indeed, these animals display muscle weakness, increased fibre denervation and a slower muscle relaxation following tetanic stimulation. This is accompanied by a shift towards slow-twitch fibres and changes in the expression levels of calcium-related genes, such as Serca1 and Casq1. Double knockout mice show a decrease in calcium decay kinetics after tetanus in vivo, suggestive of a reduced calcium reuptake. In addition, RNA sequencing analysis revealed that many downregulated genes, such as Tcap and Fhod3, are linked to sarcomere organization. These results suggest a key role for mTOR signalling in maintaining proper fibre relaxation in skeletal muscle. KEY POINTS: Skeletal muscle wasting and weakness have been associated with different pathological conditions, including sarcopenia and muscular dystrophy, and are accompanied by altered mammalian target of rapamycin (mTOR) signalling. Mammalian target of rapamycin plays a crucial role in the maintenance of muscle mass and functionality. We found that the loss of both mTOR and raptor results in contractile abnormalities, with severe muscle weakness and delayed relaxation following tetanic stimulation. These results are associated with alterations in the expression of genes involved in sarcomere organization and calcium handling and with an impairment in calcium reuptake after contraction. Taken together, these results provide a mechanistic insight into the role of mTOR in muscle contractility.
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Affiliation(s)
- Martina Baraldo
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Sabrina Zorzato
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy
| | - Achille Homère Tchampda Dondjang
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Alessia Geremia
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Leonardo Nogara
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ana Georgia Dumitras
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marta Canato
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Lorenzo Marcucci
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Center for Biosystems Dynamics Research, RIKEN, Suita, Japan
| | - Hendrik Nolte
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Bert Blaauw
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
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5
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Heemstra LA, Koch LG, Britton SL, Novak CM. Altered skeletal muscle sarco-endoplasmic reticulum Ca 2+-ATPase calcium transport efficiency after a thermogenic stimulus. Am J Physiol Regul Integr Comp Physiol 2022; 323:R628-R637. [PMID: 36094445 PMCID: PMC9602703 DOI: 10.1152/ajpregu.00173.2022] [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: 06/30/2022] [Revised: 09/01/2022] [Accepted: 09/01/2022] [Indexed: 01/22/2023]
Abstract
Exposure to predator threat induces a rapid and robust increase in skeletal muscle thermogenesis in rats. The central nervous system relays threat information to skeletal muscle through activation of the sympathetic nervous system, but muscle mechanisms mediating this thermogenesis remain unidentified. Given the relevance of sarcolipin-mediated futile calcium cycling through the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) pump to mammalian muscle nonshivering thermogenesis, we hypothesized that this plays a role in contextually induced muscle thermogenesis as well. This was assessed by measuring enzymatic activity of SERCA and sarcoplasmic reticulum Ca2+ transport, where the apparent coupling ratio (Ca2+ uptake rate divided by ATPase activity rate at a standard Ca2+ concentration) was predicted to decrease in association with muscle thermogenesis. Sprague-Dawley rats exposed to predator (ferret) odor (PO) showed a rapid decrease in the apparent coupling ratio in the soleus muscle, indicating SERCA uncoupling compared with control-odor-exposed rats. A rat model of high aerobic fitness and elevated muscle thermogenesis also demonstrated soleus muscle SERCA uncoupling relative to their obesity-prone, low-fitness counterparts. Both the high- and low-aerobic fitness rats showed soleus SERCA uncoupling with exposure to PO. Finally, no increase in sarcolipin expression in soleus muscle was detected with PO exposure. This dataset implicates muscle uncoupling of SERCA Ca2+ transport and ATP hydrolysis, likely through altered SERCA or sarcolipin function outside of translational regulation, as one contributor to the muscle thermogenesis provoked by exposure to predator threat. These data support the involvement of SERCA uncoupling in both muscle thermogenic induction and enhanced aerobic capacity.
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Affiliation(s)
- Lydia A Heemstra
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Lauren G Koch
- Department of Physiology and Pharmacology, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Steven L Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Colleen M Novak
- Department of Biological Sciences, Kent State University, Kent, Ohio
- School of Biomedical Sciences, Kent State University, Kent, Ohio
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6
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Hughes DC, Hardee JP, Waddell DS, Goodman CA. CORP: Gene delivery into murine skeletal muscle using in vivo electroporation. J Appl Physiol (1985) 2022; 133:41-59. [PMID: 35511722 DOI: 10.1152/japplphysiol.00088.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The strategy of gene delivery into skeletal muscles has provided exciting avenues in identifying new potential therapeutics towards muscular disorders and addressing basic research questions in muscle physiology through overexpression and knockdown studies. In vivo electroporation methodology offers a simple, rapidly effective technique for the delivery of plasmid DNA into post-mitotic skeletal muscle fibers and the ability to easily explore the molecular mechanisms of skeletal muscle plasticity. The purpose of this review is to describe how to robustly electroporate plasmid DNA into different hindlimb muscles of rodent models. Further, key parameters (e.g., voltage, hyaluronidase, plasmid concentration) which contribute to the successful introduction of plasmid DNA into skeletal muscle fibers will be discussed. In addition, details on processing tissue for immunohistochemistry and fiber cross-sectional area (CSA) analysis will be outlined. The overall goal of this review is to provide the basic and necessary information needed for successful implementation of in vivo electroporation of plasmid DNA and thus open new avenues of discovery research in skeletal muscle physiology.
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Affiliation(s)
- David C Hughes
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Justin P Hardee
- Centre for Muscle Research (CMR), Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
| | - David S Waddell
- Department of Biology, University of North Florida, Jacksonville, FL, United States
| | - Craig A Goodman
- Centre for Muscle Research (CMR), Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
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7
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Elowe CR, Gerson AR. Migratory disposition alters lean mass dynamics and protein metabolism in migratory White-throated Sparrows ( Zonotrichia albicollis). Am J Physiol Regul Integr Comp Physiol 2022; 323:R98-R109. [PMID: 35503523 DOI: 10.1152/ajpregu.00295.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Migratory birds seasonally increase fat stores and the capacity to use fat to fuel long-distance migratory flights. However, lean mass loss also occurs during migratory flights and, if adaptive, should exhibit seasonal changes in the capacity for protein metabolism. We conducted a photoperiod manipulation using captive White-throated Sparrows (Zonotrichia albicollis) to investigate seasonal changes in protein metabolism between the non-migratory "winter" condition and after exposure to a long-day "spring" photoperiod to stimulate the migratory condition. After photostimulation, birds in the migratory condition rapidly increased fat mass and activity of fat catabolism enzymes. Meanwhile, total lean mass did not change, but birds increased activity of protein catabolism enzymes and lost more water and lean mass during water-restricted metabolic testing. These data suggest that more protein may be catabolized during migratory seasons, corresponding with more water loss. Counter to predictions, birds in the migratory condition also showed an approximately 30-fold increase in muscle expression of sarcolipin, which binds to sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) and uncouples Ca2+ transport from ATP hydrolysis. Our documented changes to protein catabolism enzymes and whole-animal lean mass dynamics may indicate protein breakdown or increased protein turnover is adaptive during migration in songbirds.
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Affiliation(s)
- Cory R Elowe
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, United States.,Organismic and Evolutionary Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, United States
| | - Alexander R Gerson
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, United States.,Organismic and Evolutionary Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, United States
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8
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Chambers PJ, Juracic ES, Fajardo VA, Tupling AR. The role of SERCA and sarcolipin in adaptive muscle remodeling. Am J Physiol Cell Physiol 2022; 322:C382-C394. [PMID: 35044855 DOI: 10.1152/ajpcell.00198.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Sarcolipin (SLN) is a small integral membrane protein that regulates the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pump. When bound to SERCA, SLN reduces the apparent Ca2+ affinity of SERCA and uncouples SERCA Ca2+ transport from its ATP consumption. As such, SLN plays a direct role in altering skeletal muscle relaxation and energy expenditure. Interestingly, the expression of SLN is dynamic during times of muscle adaptation, where large increases in SLN content are found in response to development, atrophy, overload and disease. Several groups have suggested that increases in SLN, especially in dystrophic muscle, are deleterious to muscle function and exacerbate already abhorrent intracellular Ca2+ levels. However, there is also significant evidence to show that increased SLN content is a beneficial adaptive mechanism which protects the SERCA pump and activates Ca2+ signaling and adaptive remodeling during times of cell stress. In this review, we first discuss the role for SLN in healthy muscle during both development and overload, where SLN has been shown to activate Ca2+ signaling to promote mitochondrial biogenesis, fibre type shifts and muscle hypertrophy. Then, with respect to muscle disease, we summarize the discrepancies in the literature as to whether SLN upregulation is adaptive or maladaptive in nature. This review is the first to offer the concept of SLN hormesis in muscle disease, wherein both too much and too little SLN are detrimental to muscle health. Finally, the underlying mechanisms which activate SLN upregulation are discussed, specifically acknowledging a potential positive feedback loop between SLN and Ca2+ signaling molecules.
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Affiliation(s)
- Paige J Chambers
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Emma S Juracic
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Val A Fajardo
- Department Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - A Russell Tupling
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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9
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Oldfield C, Moffatt TL, Dolinsky VW, Duhamel TA. Sirtuin 3 overexpression preserves maximal sarco(endo)plasmic reticulum calcium ATPase activity in the skeletal muscle of mice subjected to high fat-high sucrose-feeding. Can J Physiol Pharmacol 2021; 100:361-370. [PMID: 34695364 DOI: 10.1139/cjpp-2021-0587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sarco(endo)plasmic reticulum calcium (Ca2+) ATPase (SERCA) transports Ca2+ in muscle. Impaired SERCA activity contributes to diabetic myopathy. Sirtuin (SIRT) 3 regulates muscle metabolism and function. However, it is unknown if SIRT3 regulates muscle SERCA activity. We determined if SIRT3 overexpression enhances SERCA activity in mouse gastrocnemius muscle and if SIRT3 overexpression preserves gastrocnemius SERCA activity in a model of type 2 diabetes, induced by high fat-high sucrose (HFHS)-feeding. We also determined if the acetylation status of SERCA proteins in mouse gastrocnemius is altered by SIRT3 overexpression or HFHS-feeding. Wild-type (WT) mice and SIRT3 transgenic (SIRT3TG) mice, overexpressing SIRT3 in skeletal muscle, were fed a standard- or HFHS-diet for 4-months. SIRT3TG and WT mice developed obesity and glucose intolerance after 4-months of HFHS-feeding. SERCA Vmax was higher in gastrocnemius of SIRT3TG mice, compared to WT mice. HFHS-fed mice had lower SERCA1a protein levels and lower SERCA Vmax in their gastrocnemius than control-fed mice. The decrease in SERCA Vmax in gastrocnemius muscle due to HFHS-feeding was attenuated by SIRT3 overexpression in HFHS-fed SIRT3TG mice. SERCA1a and SERCA2a acetylation in mouse gastrocnemius was not altered by genotype or diet. These findings suggest SIRT3 overexpression improves SERCA function in diabetic mouse skeletal muscle.
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Affiliation(s)
- Christopher Oldfield
- University of Manitoba Faculty of Kinesiology and Recreation Management, 175106, Winnipeg, Canada.,St. Boniface Hospital Albrechtsen Research Centre, Institute of Cardiovascular Sciences, Manitoba, Canada;
| | - Teri L Moffatt
- St Boniface General Hospital Research Centre, 120927, Winnipeg, Manitoba, Canada;
| | - Vernon W Dolinsky
- University of Manitoba, Pharmacology and Therapeutics, 601 J. Buhler Research Centre, 715 McDermot Avenue, Winnipeg, Manitoba, Canada, R3E 3P4;
| | - Todd A Duhamel
- St. Boniface General Hospital Research Center, 351 Tach� Avenue, Winnipeg, Manitoba, Canada, R2H 2A6;
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10
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Driscoll RK, Krasniewski LK, Cockey SG, Yang JH, Piao Y, Lehrmann E, Zhang Y, Michel M, Noh JH, Cui CY, Gorospe M. GRSF1 deficiency in skeletal muscle reduces endurance in aged mice. Aging (Albany NY) 2021; 13:14557-14570. [PMID: 34078750 PMCID: PMC8221292 DOI: 10.18632/aging.203151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 05/27/2021] [Indexed: 12/14/2022]
Abstract
GRSF1 is a mitochondrial RNA-binding protein important for maintaining mitochondrial function. We found that GRSF1 is highly expressed in cultured skeletal myoblasts differentiating into myotubes. To understand the physiological function of GRSF1 in vivo, we generated mice in which GRSF1 was specifically ablated in skeletal muscle. The conditional knockout mice (Grsf1cKO) appeared normal until 7-9 months of age. Importantly, however, a reduction of muscle endurance compared to wild-type controls was observed in 16- to 18-month old Grsf1cKO mice. Transcriptomic analysis revealed more than 200 mRNAs differentially expressed in Grsf1cKO muscle at this age. Notably, mRNAs encoding proteins involved in mitochondrial function, inflammation, and ion transport, including Mgarp, Cxcl10, Nfkb2, and Sln mRNAs, were significantly elevated in aged Grsf1cKO muscle. Our findings suggest that GRSF1 deficiency exacerbates the functional decline of aged skeletal muscle, likely through multiple downstream effector proteins.
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Affiliation(s)
- Riley K. Driscoll
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Linda K. Krasniewski
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Samuel G. Cockey
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Jen-Hao Yang
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Yulan Piao
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Elin Lehrmann
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Yongqing Zhang
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Marc Michel
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Ji Heon Noh
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
- Department of Biochemistry, Chungnam National University, Daejeon, Korea
| | - Chang-Yi Cui
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Myriam Gorospe
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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11
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Abstract
Age-associated changes in gene expression in skeletal muscle of healthy individuals reflect accumulation of damage and compensatory adaptations to preserve tissue integrity. To characterize these changes, RNA was extracted and sequenced from muscle biopsies collected from 53 healthy individuals (22-83 years old) of the GESTALT study of the National Institute on Aging-NIH. Expression levels of 57,205 protein-coding and non-coding RNAs were studied as a function of aging by linear and negative binomial regression models. From both models, 1134 RNAs changed significantly with age. The most differentially abundant mRNAs encoded proteins implicated in several age-related processes, including cellular senescence, insulin signaling, and myogenesis. Specific mRNA isoforms that changed significantly with age in skeletal muscle were enriched for proteins involved in oxidative phosphorylation and adipogenesis. Our study establishes a detailed framework of the global transcriptome and mRNA isoforms that govern muscle damage and homeostasis with age.
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12
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Barbot T, Beswick V, Montigny C, Quiniou É, Jamin N, Mouawad L. Deciphering the Mechanism of Inhibition of SERCA1a by Sarcolipin Using Molecular Simulations. Front Mol Biosci 2021; 7:606254. [PMID: 33614704 PMCID: PMC7890198 DOI: 10.3389/fmolb.2020.606254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/06/2020] [Indexed: 12/02/2022] Open
Abstract
SERCA1a is an ATPase calcium pump that transports Ca2+ from the cytoplasm to the sarco/endoplasmic reticulum lumen. Sarcolipin (SLN), a transmembrane peptide, regulates the activity of SERCA1a by decreasing its Ca2+ transport rate, but its mechanism of action is still not well-understood. To decipher this mechanism, we have performed normal mode analysis in the all-atom model, with the SERCA1a-SLN complex, or the isolated SERCA1a, embedded in an explicit membrane. The comparison of the results allowed us to provide an explanation at the atomic level for the action of SLN that is in good agreement with experimental observations. In our analyses, the presence of SLN locally perturbs the TM6 transmembrane helix and as a consequence modifies the position of D800, one of the key metal-chelating residues. Additionally, it reduces the flexibility of the gating residues, V304, and E309 in TM4, at the entrance of the Ca2+ binding sites, which would decrease the affinity for Ca2+. Unexpectedly, SLN has also an effect on the ATP binding site more than 35 Å away, due to the straightening of TM5, a long helix considered as the spine of the protein. The straightening of TM5 modifies the structure of the P-N linker that sits above it, and which comprises the 351DKTG354 conserved motif, resulting in an increase of the distance between ATP and the phosphorylation site. As a consequence, the turn-over rate could be affected. All this gives SERCA1a the propensity to go toward a Ca2+ low-affinity E2-like state in the presence of SLN and toward a Ca2+ high-affinity E1-like state in the absence of SLN. In addition to a general mechanism of inhibition of SERCA1a regulatory peptides, this study also provides an insight into the conformational transition between the E2 and E1 states.
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Affiliation(s)
- Thomas Barbot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Veronica Beswick
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France.,Physics Department, Evry-Val-d'Essonne University, Paris-Saclay University, Evry, France
| | - Cédric Montigny
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Éric Quiniou
- CNRS UMR9187 / INSERM U1196, Institut Curie, PSL Research University, Université Paris-Saclay, Orsay, France
| | - Nadège Jamin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Liliane Mouawad
- CNRS UMR9187 / INSERM U1196, Institut Curie, PSL Research University, Université Paris-Saclay, Orsay, France
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13
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Phospholamban and sarcolipin prevent thermal inactivation of sarco(endo)plasmic reticulum Ca2+-ATPases. Biochem J 2020; 477:4281-4294. [PMID: 33111944 DOI: 10.1042/bcj20200346] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 10/15/2020] [Accepted: 10/28/2020] [Indexed: 12/31/2022]
Abstract
Na+-K+-ATPase from mice lacking the γ subunit exhibits decreased thermal stability. Phospholamban (PLN) and sarcolipin (SLN) are small homologous proteins that regulate sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs) with properties similar to the γ subunit, through physical interactions with SERCAs. Here, we tested the hypothesis that PLN and SLN may protect against thermal inactivation of SERCAs. HEK-293 cells were co-transfected with different combinations of cDNAs encoding SERCA2a, PLN, a PLN mutant (N34A) that cannot bind to SERCA2a, and SLN. One-half of the cells were heat stressed at 40°C for 1 h (HS), and one-half were maintained at 37°C (CTL) before harvesting the cells and isolating microsomes. Compared with CTL, maximal SERCA activity was reduced by 25-35% following HS in cells that expressed either SERCA2a alone or SERCA2a and mutant PLN (N34A) whereas no change in maximal SERCA2a activity was observed in cells that co-expressed SERCA2a and either PLN or SLN following HS. Increases in SERCA2a carbonyl group content and nitrotyrosine levels that were detected following HS in cells that expressed SERCA2a alone were prevented in cells co-expressing SERCA2a with PLN or SLN, whereas co-expression of SERCA2a with mutant PLN (N34A) only prevented carbonyl group formation. In other experiments using knock-out mice, we found that thermal inactivation of SERCA was increased in cardiac left ventricle samples from Pln-null mice and in diaphragm samples from Sln-null mice, compared with WT littermates. Our results show that both PLN and SLN form a protective interaction with SERCA pumps during HS, preventing nitrosylation and oxidation of SERCA and thus preserving its maximal activity.
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14
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Stager M, Cheviron ZA. Is there a role for sarcolipin in avian facultative thermogenesis in extreme cold? Biol Lett 2020; 16:20200078. [PMID: 32516564 PMCID: PMC7336856 DOI: 10.1098/rsbl.2020.0078] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/27/2020] [Indexed: 11/12/2022] Open
Abstract
Endotherms defend their body temperature in the cold by employing shivering (ST) and/or non-shivering thermogenesis (NST). Although NST is well documented in mammals, its importance to avian heat generation is unclear. Recent work points to a prominent role for the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) in muscular NST. SERCA's involvement in both ST and NST, however, posits a tradeoff between these two heat-generating mechanisms. To explore this tradeoff, we assayed pectoralis gene expression of adult songbirds exposed to chronic temperature acclimations. Counter to mammal models, we found that cold-acclimated birds downregulated the expression of sarcolipin (SLN), a gene coding for a peptide that promotes heat generation by uncoupling SERCA Ca2+ transport from ATP hydrolysis, indicating a reduced potential for muscular NST. We also found differential expression of many genes involved in Ca2+ cycling and muscle contraction and propose that decreased SLN could promote increased pectoralis contractility for ST. Moreover, SLN transcript abundance negatively correlated with peak oxygen consumption under cold exposure (a proxy for ST) across individuals, and higher SLN transcript abundance escalated an individual's risk of hypothermia in acute cold. Our results therefore suggest that SLN-mediated NST may not be an important mechanism of-and could be a hindrance to-avian thermoregulation in extreme cold.
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Affiliation(s)
- Maria Stager
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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15
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Wang S, Gopinath T, Veglia G. Improving the quality of oriented membrane protein spectra using heat-compensated separated local field experiments. JOURNAL OF BIOMOLECULAR NMR 2019; 73:617-624. [PMID: 31463642 PMCID: PMC6861693 DOI: 10.1007/s10858-019-00273-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/21/2019] [Indexed: 05/03/2023]
Abstract
Oriented sample solid-state NMR (OS-ssNMR) spectroscopy is a powerful technique to determine the topology of membrane proteins in oriented lipid bilayers. Separated local field (SLF) experiments are central to this technique as they provide first-order orientational restraints, i.e., dipolar couplings and anisotropic chemical shifts. Despite the use of low-E (or E-free) probes, the heat generated during the execution of 2D and 3D SLF pulse sequences causes sizeable line-shape distortions. Here, we propose a new heat-compensated SE-SAMPI4 (hcSE-SAMPI4) pulse sequence that holds the temperature constant for the duration of the experiment. This modification of the SE-SAMPI4 results in sharper and more intense resonances without line-shape distortions. The spectral improvements are even more apparent when paramagnetic relaxation agents are used to speed up data collection. We tested the hcSE-SAMPI4 pulse sequence on a single-span membrane protein, sarcolipin (SLN), reconstituted in magnetically aligned lipid bicelles. In addition to eliminating peak distortions, the hcSE-SAMPI4 experiment increased the average signal-to-noise ratio by 20% with respect to the original SE-SAMPI4.
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Affiliation(s)
- Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - T Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
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16
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Tomiya S, Tamura Y, Kouzaki K, Kotani T, Wakabayashi Y, Noda M, Nakazato K. Cast immobilization of hindlimb upregulates sarcolipin expression in atrophied skeletal muscles and increases thermogenesis in C57BL/6J mice. Am J Physiol Regul Integr Comp Physiol 2019; 317:R649-R661. [PMID: 31433681 DOI: 10.1152/ajpregu.00118.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mechanical unloading impairs cytosolic calcium (Ca2+) homeostasis in skeletal muscles. In this study, we investigated whether sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) itself or one of the regulators of the Ca2+ SERCA pump, sarcolipin (SLN), is altered to deregulate Ca2+ homeostasis in cast immobilized, atrophied muscles. Hindlimb muscles of 8-wk-old male C57BL/6J mice were subjected to bilateral cast immobilization for 2 wk. Two-week-cast immobilization induced both body weight and skeletal muscle loss. Highly phosphorylated Ca2+/calmodulin-dependent protein kinase II in the atrophied muscles suggested that cytosolic Ca2+ concentration was elevated. Extremely high expression levels of SLN mRNA and protein were observed in the atrophied muscles. Upregulation of SLN at the transcriptional level was supported by low RCAN1 expression, which is a negative regulator of SLN. We treated C2C12 cells with dexamethasone to mimic muscle atrophy in vitro and showed a direct relationship between high SLN mRNA expression and low Ca2+ uptake by sarcoplasmic reticulum. Since SLN reportedly plays a role in nonshivering thermogenesis, we performed a cold tolerance test of the whole body. As a result, we found that mice with cast immobilization showed high cold tolerance, suggesting that cast immobilization promoted whole body thermogenesis. Although the activity level was decreased during cast immobilization without change in food intake, adipose tissue weights also decreased significantly after cast immobilization. Concomitantly, we conclude that cast immobilization of hindlimb increased thermogenesis in C57Bl/6J mice, probably via high expression of SLN.
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Affiliation(s)
- Shigeto Tomiya
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Yuki Tamura
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan.,Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Karina Kouzaki
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Takaya Kotani
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Yuka Wakabayashi
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Masafumi Noda
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan.,Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
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17
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Gamu D, Juracic ES, Fajardo VA, Rietze BA, Tran K, Bombardier E, Tupling AR. Phospholamban deficiency does not alter skeletal muscle SERCA pumping efficiency or predispose mice to diet-induced obesity. Am J Physiol Endocrinol Metab 2019; 316:E432-E442. [PMID: 30601702 DOI: 10.1152/ajpendo.00288.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pump is a major contributor to skeletal muscle Ca2+ homeostasis and metabolic rate. SERCA activity can become adaptively uncoupled by its regulator sarcolipin (SLN) to increase the energy demand of Ca2+ pumping, preventing excessive obesity and glucose intolerance in mice. Several other SERCA regulators bear structural and functional resemblance to SLN, including phospholamban (PLN). Here, we sought to examine whether endogenous levels of skeletal muscle PLN control SERCA Ca2+ pumping efficiency and whole body metabolism. Using PLN-null mice ( Pln-/-), we found that soleus (SOL) muscle's SERCA pumping efficiency (measured as an apparent coupling ratio: Ca2+ uptake/ATP hydrolysis) was unaffected by PLN. Expression of Ca2+-handling proteins within the SOL, including SLN, were comparable between Pln-/- and wild-type (WT) littermates, as were fiber-type characteristics. Not surprisingly then, Pln-/- mice developed a similar degree of diet-induced obesity and glucose intolerance as WT controls when given a "Western" high-fat diet. Lack of an excessively obesogenic phenotype of Pln-/- could not be explained by compensation from skeletal muscle SLN or brown adipose tissue uncoupling protein-1 content. In agreement with several other reports, our study lends support to the notion that PLN serves a functionally distinct role from that of SLN in skeletal muscle physiology.
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Affiliation(s)
- Daniel Gamu
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - Emma Sara Juracic
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - Val A Fajardo
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | | | - Khanh Tran
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
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18
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Qaisar R, Bhaskaran S, Premkumar P, Ranjit R, Natarajan KS, Ahn B, Riddle K, Claflin DR, Richardson A, Brooks SV, Van Remmen H. Oxidative stress-induced dysregulation of excitation-contraction coupling contributes to muscle weakness. J Cachexia Sarcopenia Muscle 2018; 9:1003-1017. [PMID: 30073804 PMCID: PMC6204588 DOI: 10.1002/jcsm.12339] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/25/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND We have previously shown that the deletion of the superoxide scavenger, CuZn superoxide dismutase, in mice (Sod1-/- mice) results in increased oxidative stress and an accelerated loss of skeletal muscle mass and force that mirror the changes seen in old control mice. The goal of this study is to define the effect of oxidative stress and ageing on muscle weakness and the Excitation Contraction (EC) coupling machinery in age-matched adult (8-10 months) wild-type (WT) and Sod1-/- mice in comparison with old (25-28 months) WT mice. METHODS In vitro contractile assays were used to measure muscle contractile parameters. The activity of the sarcoplasmic reticulum Ca2+ ATPase (SERCA) pump was measured using an NADH-linked enzyme assay. Immunoblotting and immunofluorescence techniques were used to measure protein expression, and real-time reverse transcription PCR was used to measure gene expression. RESULTS The specific force generated by the extensor digitorum longus muscle was reduced in the Sod1-/- and old WT mice compared with young WT mice along with significant prolongation of time to peak force, increased half relaxation time, and disruption of intracellular calcium handling. The maximal activity of the SERCA calcium uptake pump was significantly reduced in gastrocnemius muscle from both old WT (≈14%) and adult Sod1-/- (≈33%) mice compared with young WT mice along with increased expression of sarcolipin, a known inhibitor of SERCA activity. Protein levels of the voltage sensor and calcium uptake channel proteins dihydropyridine receptor α1 and SERCA2 were significantly elevated (≈45% and ≈57%, respectively), while the ratio of calstabin, a channel stabilizing protein, to ryanodine receptor was significantly reduced (≈21%) in Sod1-/- mice compared with young WT mice. The changes in calcium handling were accompanied by substantially elevated levels of global protein carbonylation and lipid peroxidation. CONCLUSIONS Our data suggest that the muscle weakness in Sod1-/- and old WT mice is in part driven by reactive oxygen species-mediated EC uncoupling and supports a role for reduced SERCA pump activity in compromised muscle function. The novel quantitative mechanistic data provided here can lead to potential therapeutic interventions of SERCA dysfunction for sarcopenia and muscle diseases.
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Affiliation(s)
- Rizwan Qaisar
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Shylesh Bhaskaran
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Pavithra Premkumar
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Rojina Ranjit
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | | | - Bumsoo Ahn
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Kaitlyn Riddle
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Dennis R Claflin
- Department of Surgery, Section of Plastic Surgery, University of Michigan, Ann Arbor, MI, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Arlan Richardson
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Oklahoma City VA Medical Center, Oklahoma City, OK, USA.,Department of Geriatric Medicine and the Reynolds Oklahoma Center of Aging, Oklahoma University Health Science Center, Oklahoma City, OK, USA
| | - Susan V Brooks
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Holly Van Remmen
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Oklahoma City VA Medical Center, Oklahoma City, OK, USA
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19
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Bal NC, Sahoo SK, Maurya SK, Periasamy M. The Role of Sarcolipin in Muscle Non-shivering Thermogenesis. Front Physiol 2018; 9:1217. [PMID: 30319433 PMCID: PMC6170647 DOI: 10.3389/fphys.2018.01217] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 08/13/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Naresh C Bal
- KIIT School of Biotechnology, KIIT University, Bhubaneswar, India
| | - Sanjaya K Sahoo
- Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, FL, United States
| | - Santosh K Maurya
- Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, FL, United States
| | - Muthu Periasamy
- Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, FL, United States
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20
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Abstract
The calcium pump (a.k.a. Ca2+-ATPase or SERCA) is a membrane transport protein ubiquitously found in the endoplasmic reticulum (ER) of all eukaryotic cells. As a calcium transporter, SERCA maintains the low cytosolic calcium level that enables a vast array of signaling pathways and physiological processes (e.g. synaptic transmission, muscle contraction, fertilization). In muscle cells, SERCA promotes relaxation by pumping calcium ions from the cytosol into the lumen of the sarcoplasmic reticulum (SR), the main storage compartment for intracellular calcium. X-ray crystallographic studies have provided an extensive understanding of the intermediate states that SERCA populates as it progresses through the calcium transport cycle. Historically, SERCA is also known to be regulated by small transmembrane peptides, phospholamban (PLN) and sarcolipin (SLN). PLN is expressed in cardiac muscle, whereas SLN predominates in skeletal and atrial muscle. These two regulatory subunits play critical roles in cardiac contractility. While our understanding of these regulatory mechanisms are still developing, SERCA and PLN are one of the best understood examples of peptide-transporter regulatory interactions. Nonetheless, SERCA appeared to have only two regulatory subunits, while the related sodium pump (a.k.a. Na+, K+-ATPase) has at least nine small transmembrane peptides that provide tissue specific regulation. The last few years have seen a renaissance in our understanding of SERCA regulatory subunits. First, structures of the SERCA-SLN and SERCA-PLN complexes revealed molecular details of their interactions. Second, an array of micropeptides concealed within long non-coding RNAs have been identified as new SERCA regulators. This chapter will describe our current understanding of SERCA structure, function, and regulation.
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21
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Wang S, Gopinath T, Veglia G. Application of paramagnetic relaxation enhancements to accelerate the acquisition of 2D and 3D solid-state NMR spectra of oriented membrane proteins. Methods 2017; 138-139:54-61. [PMID: 29274874 DOI: 10.1016/j.ymeth.2017.12.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/14/2017] [Accepted: 12/19/2017] [Indexed: 12/21/2022] Open
Abstract
Oriented sample solid-state NMR (OS-ssNMR) spectroscopy is uniquely suited to determine membrane protein topology at the atomic resolution in liquid crystalline bilayers under physiological temperature. However, the inherent low sensitivity of this technique has hindered the throughput of multidimensional experiments necessary for resonance assignments and structure determination. In this work, we show that doping membrane protein bicelle preparations with paramagnetic ion chelated lipids and exploiting paramagnetic relaxation effects it is possible to accelerate the acquisition of both 2D and 3D multidimensional experiments with significant saving in time. We demonstrate the efficacy of this method for a small membrane protein, sarcolipin, reconstituted in DMPC/POPC/DHPC oriented bicelles. In particular, using Cu2+-DMPE-DTPA as a dopant, we observed a decrease of 1H T1 of sarcolipin by 2/3, allowing us to reduce the recycle delay up to 3 times. We anticipate that these new developments will enable the routine acquisition of multidimensional OS-ssNMR experiments.
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Affiliation(s)
- Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
| | - T Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States; Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, United States.
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22
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Fajardo VA, Rietze BA, Chambers PJ, Bellissimo C, Bombardier E, Quadrilatero J, Tupling AR. Effects of sarcolipin deletion on skeletal muscle adaptive responses to functional overload and unload. Am J Physiol Cell Physiol 2017; 313:C154-C161. [PMID: 28592414 DOI: 10.1152/ajpcell.00291.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 05/30/2017] [Accepted: 05/30/2017] [Indexed: 12/22/2022]
Abstract
Overexpression of sarcolipin (SLN), a regulator of sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs), stimulates calcineurin signaling to enhance skeletal muscle oxidative capacity. Some studies have shown that calcineurin may also control skeletal muscle mass and remodeling in response to functional overload and unload stimuli by increasing myofiber size and the proportion of slow fibers. To examine whether SLN might mediate these adaptive responses, we performed soleus and gastrocnemius tenotomy in wild-type (WT) and Sln-null (Sln-/-) mice and examined the overloaded plantaris and unloaded/tenotomized soleus muscles. In the WT overloaded plantaris, we observed ectopic expression of SLN, myofiber hypertrophy, increased fiber number, and a fast-to-slow fiber type shift, which were associated with increased calcineurin signaling (NFAT dephosphorylation and increased stabilin-2 protein content) and reduced SERCA activity. In the WT tenotomized soleus, we observed a 14-fold increase in SLN protein, myofiber atrophy, decreased fiber number, and a slow-to-fast fiber type shift, which were also associated with increased calcineurin signaling and reduced SERCA activity. Genetic deletion of Sln altered these physiological outcomes, with the overloaded plantaris myofibers failing to grow in size and number, and transition towards the slow fiber type, while the unloaded soleus muscles exhibited greater reductions in fiber size and number, and an accelerated slow-to-fast fiber type shift. In both the Sln-/- overloaded and unloaded muscles, these findings were associated with elevated SERCA activity and blunted calcineurin signaling. Thus, SLN plays an important role in adaptive muscle remodeling potentially through calcineurin stimulation, which could have important implications for other muscle diseases and conditions.
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Affiliation(s)
- Val A Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo Ontario, Canada
| | - Bradley A Rietze
- Department of Kinesiology, University of Waterloo, Waterloo Ontario, Canada
| | - Paige J Chambers
- Department of Kinesiology, University of Waterloo, Waterloo Ontario, Canada
| | | | - Eric Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo Ontario, Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo Ontario, Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo Ontario, Canada
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Gamu D, Trinh A, Fajardo VA, Bombardier E, Tupling AR. Sarcolipin expression is not required for the mitochondrial enzymatic response to physical activity or diet. J Appl Physiol (1985) 2017; 122:1276-1283. [PMID: 28183820 DOI: 10.1152/japplphysiol.00833.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 02/06/2017] [Accepted: 02/06/2017] [Indexed: 11/22/2022] Open
Abstract
In mice, transgenic manipulation of Ca2+-handling proteins is sufficient to alter the metabolic phenotype of muscle. We have previously shown that ablation of sarcolipin (SLN), a regulatory protein and uncoupler of sarco(endo)plasmic reticulum Ca2+-ATPases, leads to excessive diet-induced obesity and glucose intolerance in mice. However, it is unclear how loss of SLN per se affects muscle oxidative capacity and the ability of mitochondria to adapt to physiological stimuli, such as exercise training or calorie overload. To address this question, Sln-/- and wild-type (WT) littermates were given access to voluntary running wheels or underwent a treadmill training protocol for 8 wk. Furthermore, a separate group of mice were given a high-fat diet (42% kcal from fat for 8 wk) to determine whether the excessively obese phenotype of Sln-/- mice is associated with altered oxidative capacity. While voluntary running was insufficient to elicit mitochondrial adaptations, treadmill-trained mice showed significant increases (P < 0.05) in the maximal activities of succinate dehydrogenase (+11%), citrate synthase (+12%), cytochrome oxidase (COX: +17%), along with increased protein expression of cytochrome c (+34%) and COX IV (+28%), which were irrespective of SLN expression. Lastly, no changes in the activities of mitochondrial marker enzymes existed with high-fat feeding, regardless of genotype. Together, these findings indicate that SLN is not required for the regulation of oxidative capacity in response to physiological stress, namely exercise or caloric surfeit.NEW & NOTEWORTHY Sarcolipin (SLN) has gained considerable attention for its uncoupling role of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA). Because of SLN's ability to alter both cellular energy use and cytosolic [Ca2+], the potential exists for a regulatory role of mitochondrial biogenesis. Herein, we show skeletal muscle oxidative capacity to be unaltered in mice lacking SLN following exercise training or high-fat feeding. Our results contrast with published studies of SLN-overexpressing mice, possibly owing to supraphysiological uncoupling of SERCA.
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Affiliation(s)
- Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Anton Trinh
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Val A Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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24
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Fajardo VA, Gamu D, Mitchell A, Bloemberg D, Bombardier E, Chambers PJ, Bellissimo C, Quadrilatero J, Tupling AR. Sarcolipin deletion exacerbates soleus muscle atrophy and weakness in phospholamban overexpressing mice. PLoS One 2017; 12:e0173708. [PMID: 28278204 PMCID: PMC5344511 DOI: 10.1371/journal.pone.0173708] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 02/24/2017] [Indexed: 11/18/2022] Open
Abstract
Sarcolipin (SLN) and phospholamban (PLN) are two small proteins that regulate the sarco(endo)plasmic reticulum Ca2+-ATPase pumps. In a recent study, we discovered that Pln overexpression (PlnOE) in slow-twitch type I skeletal muscle fibers drastically impaired SERCA function and caused a centronuclear myopathy-like phenotype, severe muscle atrophy and weakness, and an 8 to 9-fold upregulation of SLN protein in the soleus muscles. Here, we sought to determine the physiological role of SLN upregulation, and based on its role as a SERCA inhibitor, we hypothesized that it would represent a maladaptive response that contributes to the SERCA dysfunction and the overall myopathy observed in the PlnOE mice. To this end, we crossed Sln-null (SlnKO) mice with PlnOE mice to generate a PlnOE/SlnKO mouse colony and assessed SERCA function, CNM pathology, in vitro contractility, muscle mass, calcineurin signaling, daily activity and food intake, and proteolytic enzyme activity. Our results indicate that genetic deletion of Sln did not improve SERCA function nor rescue the CNM phenotype, but did result in exacerbated muscle atrophy and weakness, due to a failure to induce type II fiber compensatory hypertrophy and a reduction in total myofiber count. Mechanistically, our findings suggest that impaired calcineurin activation and resultant decreased expression of stabilin-2, and/or impaired autophagic signaling could be involved. Future studies should examine these possibilities. In conclusion, our study demonstrates the importance of SLN upregulation in combating muscle myopathy in the PlnOE mice, and since SLN is upregulated across several myopathies, our findings may reveal SLN as a novel and universal therapeutic target.
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Affiliation(s)
- Val A. Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Andrew Mitchell
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Darin Bloemberg
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Paige J. Chambers
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Catherine Bellissimo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - A. Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
- * E-mail:
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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26
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Sakakibara I, Wurmser M, Dos Santos M, Santolini M, Ducommun S, Davaze R, Guernec A, Sakamoto K, Maire P. Six1 homeoprotein drives myofiber type IIA specialization in soleus muscle. Skelet Muscle 2016; 6:30. [PMID: 27597886 PMCID: PMC5011358 DOI: 10.1186/s13395-016-0102-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/16/2016] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Adult skeletal muscles are composed of slow and fast myofiber subtypes which each express selective genes required for their specific contractile and metabolic activity. Six homeoproteins are transcription factors regulating muscle cell fate through activation of myogenic regulatory factors and driving fast-type gene expression during embryogenesis. RESULTS We show here that Six1 protein accumulates more robustly in the nuclei of adult fast-type muscles than in adult slow-type muscles, this specific enrichment takes place during perinatal growth. Deletion of Six1 in soleus impaired fast-type myofiber specialization during perinatal development, resulting in a slow phenotype and a complete lack of Myosin heavy chain 2A (MyHCIIA) expression. Global transcriptomic analysis of wild-type and Six1 mutant myofibers identified the gene networks controlled by Six1 in adult soleus muscle. This analysis showed that Six1 is required for the expression of numerous genes encoding fast-type sarcomeric proteins, glycolytic enzymes and controlling intracellular calcium homeostasis. Parvalbumin, a key player of calcium buffering, in particular, is a direct target of Six1 in the adult myofiber. CONCLUSIONS This analysis revealed that Six1 controls distinct aspects of adult muscle physiology in vivo, and acts as a main determinant of fast-fiber type acquisition and maintenance.
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Affiliation(s)
- Iori Sakakibara
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
- Division of Integrative Pathophysiology, Proteo-Science Center, Graduate School of Medicine, Ehime University, Ehime, Japan
| | - Maud Wurmser
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
| | - Matthieu Dos Santos
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
| | - Marc Santolini
- Laboratoire de Physique Statistique, CNRS, Université P. et M. Curie, Université D. Diderot, École Normale Supérieure, Paris, 75005 France
| | - Serge Ducommun
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland
| | - Romain Davaze
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
| | - Anthony Guernec
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
| | - Kei Sakamoto
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland
| | - Pascal Maire
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
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27
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Treves S, Jungbluth H, Voermans N, Muntoni F, Zorzato F. Ca 2+ handling abnormalities in early-onset muscle diseases: Novel concepts and perspectives. Semin Cell Dev Biol 2016; 64:201-212. [PMID: 27427513 DOI: 10.1016/j.semcdb.2016.07.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 07/14/2016] [Indexed: 12/17/2022]
Abstract
The physiological process by which Ca2+ is released from the sarcoplasmic reticulum is called excitation-contraction coupling; it is initiated by an action potential which travels deep into the muscle fiber where it is sensed by the dihydropyridine receptor, a voltage sensing L-type Ca2+channel localized on the transverse tubules. Voltage-induced conformational changes in the dihydropyridine receptor activate the ryanodine receptor Ca2+ release channel of the sarcoplasmic reticulum. The released Ca2+ binds to troponin C, enabling contractile thick-thin filament interactions. The Ca2+ is subsequently transported back into the sarcoplasmic reticulum by specialized Ca2+ pumps (SERCA), preparing the muscle for a new cycle of contraction. Although other proteins are involved in excitation-contraction coupling, the mechanism described above emphasizes the unique role played by the two Ca2+ channels (the dihydropyridine receptor and the ryanodine receptor), the SERCA Ca2+ pumps and the exquisite spatial organization of the membrane compartments endowed with the proteins responsible for this mechanism to function rapidly and efficiently. Research over the past two decades has uncovered the fine details of excitation-contraction coupling under normal conditions while advances in genomics have helped to identify mutations in novel genes in patients with neuromuscular disorders. While it is now clear that many patients with congenital muscle diseases carry mutations in genes encoding proteins directly involved in Ca2+ homeostasis, it has become apparent that mutations are also present in genes encoding for proteins not thought to be directly involved in Ca2+ regulation. Ongoing research in the field now focuses on understanding the functional effect of individual mutations, as well as understanding the role of proteins not specifically located in the sarcoplasmic reticulum which nevertheless are involved in Ca2+ regulation or excitation-contraction coupling. The principal challenge for the future is the identification of drug targets that can be pharmacologically manipulated by small molecules, with the ultimate aim to improve muscle function and quality of life of patients with congenital muscle disorders. The aim of this review is to give an overview of the most recent findings concerning Ca2+ dysregulation and its impact on muscle function in patients with congenital muscle disorders due to mutations in proteins involved in excitation-contraction coupling and more broadly on Ca2+ homeostasis.
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Affiliation(s)
- Susan Treves
- Departments of Biomedicine and Anesthesia, Basel University Hospital, 4031 Basel, Switzerland; Department of Life Sciences, General Pathology Section, University of Ferrara, 44100 Ferrara, Italy.
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, St. Thomas' Hospital, London, United Kingdom; Randall Division for Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, United Kingdom; Department of Basic and Clinical Neuroscience, IoPPN, King's College, London, United Kingdom
| | - Nicol Voermans
- Department of Neurology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, United Kingdom
| | - Francesco Zorzato
- Departments of Biomedicine and Anesthesia, Basel University Hospital, 4031 Basel, Switzerland; Department of Life Sciences, General Pathology Section, University of Ferrara, 44100 Ferrara, Italy
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Riedl I, Osler ME, Björnholm M, Egan B, Nader GA, Chibalin AV, Zierath JR. AMPKγ3 is dispensable for skeletal muscle hypertrophy induced by functional overload. Am J Physiol Endocrinol Metab 2016; 310:E461-72. [PMID: 26758685 PMCID: PMC4796264 DOI: 10.1152/ajpendo.00387.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/06/2016] [Indexed: 12/25/2022]
Abstract
Mechanisms regulating skeletal muscle growth involve a balance between the activity of serine/threonine protein kinases, including the mammalian target of rapamycin (mTOR) and 5'-AMP-activated protein kinase (AMPK). The contribution of different AMPK subunits to the regulation of cell growth size remains inadequately characterized. Using AMPKγ3 mutant-overexpressing transgenic Tg-Prkag3(225Q) and AMPKγ3-knockout (Prkag3(-/-)) mice, we investigated the requirement for the AMPKγ3 isoform in functional overload-induced muscle hypertrophy. Although the genetic disruption of the γ3 isoform did not impair muscle growth, control sham-operated AMPKγ3-transgenic mice displayed heavier plantaris muscles in response to overload hypertrophy and underwent smaller mass gain and lower Igf1 expression compared with wild-type littermates. The mTOR signaling pathway was upregulated with functional overload but unchanged between genetically modified animals and wild-type littermates. Differences in AMPK-related signaling pathways between transgenic, knockout, and wild-type mice did not impact muscle hypertrophy. Glycogen content was increased following overload in wild-type mice. In conclusion, our functional, transcriptional, and signaling data provide evidence against the involvement of the AMPKγ3 isoform in the regulation of skeletal muscle hypertrophy. Thus, the AMPKγ3 isoform is dispensable for functional overload-induced muscle growth. Mechanical loading can override signaling pathways that act as negative effectors of mTOR signaling and consequently promote skeletal muscle hypertrophy.
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Affiliation(s)
- Isabelle Riedl
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Megan E Osler
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Marie Björnholm
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Brendan Egan
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Institute for Sport and Health, School of Public Health, Physiotherapy, and Population Science, University College Dublin, Belfield, Dublin, Ireland
| | - Gustavo A Nader
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and
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29
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Autzen HE, Siuda I, Sonntag Y, Nissen P, Møller JV, Thøgersen L. Regulation of the Ca(2+)-ATPase by cholesterol: a specific or non-specific effect? Mol Membr Biol 2015; 32:75-87. [PMID: 26260074 DOI: 10.3109/09687688.2015.1073382] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Like other integral membrane proteins, the activity of the Sarco/Endoplasmic Reticulum Ca(2+)-ATPase (SERCA) is regulated by the membrane environment. Cholesterol is present in the endoplasmic reticulum membrane at low levels, and it has the potential to affect SERCA activity both through direct, specific interaction with the protein or through indirect interaction through changes of the overall membrane properties. There are experimental data arguing for both modes of action for a cholesterol-mediated regulation of SERCA. In the current study, coarse-grained molecular dynamics simulations are used to address how a mixed lipid-cholesterol membrane interacts with SERCA. Candidates for direct regulatory sites with specific cholesterol binding modes are extracted from the simulations. The binding pocket for thapsigargin, a nanomolar inhibitor of SERCA, has been suggested as a cholesterol binding site. However, the thapsigargin binding pocket displayed very little cholesterol occupation in the simulations. Neither did atomistic simulations of cholesterol in the thapsigargin binding pocket support any specific interaction. The current study points to a non-specific effect of cholesterol on SERCA activity, and offers an alternative interpretation of the experimental results used to argue for a specific effect.
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Affiliation(s)
- Henriette Elisabeth Autzen
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,b Department of Molecular Biology and Genetics , Aarhus University , Aarhus , Denmark
| | - Iwona Siuda
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,c Bioinformatics Research Centre (BiRC) , Aarhus , Denmark , and
| | - Yonathan Sonntag
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,b Department of Molecular Biology and Genetics , Aarhus University , Aarhus , Denmark
| | - Poul Nissen
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,b Department of Molecular Biology and Genetics , Aarhus University , Aarhus , Denmark
| | - Jesper Vuust Møller
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,d Department of Biomedicine , Aarhus University , Aarhus , Denmark
| | - Lea Thøgersen
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,c Bioinformatics Research Centre (BiRC) , Aarhus , Denmark , and
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30
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Fajardo VA, Bombardier E, McMillan E, Tran K, Wadsworth BJ, Gamu D, Hopf A, Vigna C, Smith IC, Bellissimo C, Michel RN, Tarnopolsky MA, Quadrilatero J, Tupling AR. Phospholamban overexpression in mice causes a centronuclear myopathy-like phenotype. Dis Model Mech 2015; 8:999-1009. [PMID: 26035394 PMCID: PMC4527296 DOI: 10.1242/dmm.020859] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/21/2015] [Indexed: 12/16/2022] Open
Abstract
Centronuclear myopathy (CNM) is a congenital myopathy that is histopathologically characterized by centrally located nuclei, central aggregation of oxidative activity, and type I fiber predominance and hypotrophy. Here, we obtained commercially available mice overexpressing phospholamban (PlnOE), a well-known inhibitor of sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs), in their slow-twitch type I skeletal muscle fibers to determine the effects on SERCA function. As expected with a 6- to 7-fold overexpression of phospholamban, SERCA dysfunction was evident in PlnOE muscles, with marked reductions in rates of Ca2+ uptake, maximal ATPase activity and the apparent affinity of SERCA for Ca2+. However, our most significant discovery was that the soleus and gluteus minimus muscles from the PlnOE mice displayed overt signs of myopathy: they histopathologically resembled human CNM, with centrally located nuclei, central aggregation of oxidative activity, type I fiber predominance and hypotrophy, progressive fibrosis and muscle weakness. This phenotype is associated with significant upregulation of muscle sarcolipin and dynamin 2, increased Ca2+-activated proteolysis, oxidative stress and protein nitrosylation. Moreover, in our assessment of muscle biopsies from three human CNM patients, we found a significant 53% reduction in SERCA activity and increases in both total and monomeric PLN content compared with five healthy subjects, thereby justifying future studies with more CNM patients. Altogether, our results suggest that the commercially available PlnOE mouse phenotypically resembles human CNM and could be used as a model to test potential mechanisms and therapeutic strategies. To date, there is no cure for CNM and our results suggest that targeting SERCA function, which has already been shown to be an effective therapeutic target for murine muscular dystrophy and human cardiomyopathy, might represent a novel therapeutic strategy to combat CNM. Summary: Phospholamban overexpression in mouse slow-twitch muscle impairs SERCA function and causes histopathological features associated with human centronuclear myopathy.
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Affiliation(s)
- Val A Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Elliott McMillan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Khanh Tran
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Brennan J Wadsworth
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Andrew Hopf
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Chris Vigna
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Ian C Smith
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Catherine Bellissimo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Robin N Michel
- Department of Exercise Science, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Mark A Tarnopolsky
- Departement of Kinesiology, McMaster University, Hamilton, Ontario L8N 3Z5, Canada Department of Pediatrics, McMaster University, Hamilton, Ontario L8N 3Z5, Canada Department of Medicine, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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31
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Gamu D, Bombardier E, Smith IC, Fajardo VA, Tupling AR. Sarcolipin Provides a Novel Muscle-Based Mechanism for Adaptive Thermogenesis. Exerc Sport Sci Rev 2014; 42:136-42. [DOI: 10.1249/jes.0000000000000016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Schneider JS, Shanmugam M, Gonzalez JP, Lopez H, Gordan R, Fraidenraich D, Babu GJ. Increased sarcolipin expression and decreased sarco(endo)plasmic reticulum Ca2+ uptake in skeletal muscles of mouse models of Duchenne muscular dystrophy. J Muscle Res Cell Motil 2013; 34:349-56. [DOI: 10.1007/s10974-013-9350-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 05/27/2013] [Indexed: 02/02/2023]
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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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Gorski PA, Glaves JP, Vangheluwe P, Young HS. Sarco(endo)plasmic reticulum calcium ATPase (SERCA) inhibition by sarcolipin is encoded in its luminal tail. J Biol Chem 2013; 288:8456-8467. [PMID: 23362265 DOI: 10.1074/jbc.m112.446161] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The sarco(endo)plasmic reticulum calcium ATPase (SERCA) is regulated in a tissue-dependent manner via interaction with the short integral membrane proteins phospholamban (PLN) and sarcolipin (SLN). Although defects in SERCA activity are known to cause heart failure, the regulatory mechanisms imposed by PLN and SLN could have clinical implications for both heart and skeletal muscle diseases. PLN and SLN have significant sequence homology in their transmembrane regions, suggesting a similar mode of binding to SERCA. However, unlike PLN, SLN has a conserved C-terminal luminal tail composed of five amino acids ((27)RSYQY), which may contribute to a distinct SERCA regulatory mechanism. We have functionally characterized alanine mutants of the C-terminal tail of SLN using co-reconstituted proteoliposomes of SERCA and SLN. We found that Arg(27) and Tyr(31) are essential for SLN function. We also tested the effect of a truncated variant of SLN (Arg(27)stop) and extended chimeras of PLN with the five luminal residues of SLN added to its C terminus. The Arg(27)stop form of SLN resulted in loss of function, whereas the PLN chimeras resulted in superinhibition with characteristics of both PLN and SLN. Based on our results, we propose that the C-terminal tail of SLN is a distinct, essential domain in the regulation of SERCA and that the functional properties of the SLN tail can be transferred to PLN.
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Affiliation(s)
- Przemek A Gorski
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - John Paul Glaves
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada; National Institute for Nanotechnology, University of Alberta, Edmonton, Alberta T6G 2M9, Canada
| | - Peter Vangheluwe
- Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, B3000 Leuven, Belgium
| | - Howard S Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada; National Institute for Nanotechnology, University of Alberta, Edmonton, Alberta T6G 2M9, Canada.
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Sahoo SK, Shaikh SA, Sopariwala DH, Bal NC, Periasamy M. Sarcolipin protein interaction with sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) is distinct from phospholamban protein, and only sarcolipin can promote uncoupling of the SERCA pump. J Biol Chem 2013; 288:6881-9. [PMID: 23341466 DOI: 10.1074/jbc.m112.436915] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Sarco(endo)plasmic reticulum Ca(2+)ATPase (SERCA) pump activity is modulated by phospholamban (PLB) and sarcolipin (SLN) in cardiac and skeletal muscle. Recent data suggest that SLN could play a role in muscle thermogenesis by promoting uncoupling of the SERCA pump (Lee, A.G. (2002) Curr. Opin. Struct. Biol. 12, 547-554 and Bal, N. C., Maurya, S. K., Sopariwala, D. H., Sahoo, S. K., Gupta, S. C., Shaikh, S. A., Pant, M., Rowland, L. A., Bombardier, E., Goonasekera, S. A., Tupling, A. R., Molkentin, J. D., and Periasamy, M. (2012) Nat. Med. 18, 1575-1579), but the mechanistic details are unknown. To better define how binding of SLN to SERCA promotes uncoupling of SERCA, we compared SLN and SERCA1 interaction with that of PLB in detail. The homo-bifunctional cross-linker (1,6-bismaleimidohexane) was employed to detect dynamic protein interaction during the SERCA cycle. Our studies reveal that SLN differs significantly from PLB: 1) SLN primarily affects the Vmax of SERCA-mediated Ca(2+) uptake but not the pump affinity for Ca(2+); 2) SLN can bind to SERCA in the presence of high Ca(2+), but PLB can only interact to the ATP-bound Ca(2+)-free E2 state; and 3) unlike PLB, SLN interacts with SERCA throughout the kinetic cycle and promotes uncoupling of the SERCA pump. Using SERCA transmembrane mutants, we additionally show that PLB and SLN can bind to the same groove but interact with a different set of residues on SERCA. These data collectively suggest that SLN is functionally distinct from PLB; its ability to interact with SERCA in the presence of Ca(2+) causes uncoupling of the SERCA pump and increased heat production.
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Affiliation(s)
- Sanjaya K Sahoo
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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Riley G, Syeda F, Kirchhof P, Fabritz L. An introduction to murine models of atrial fibrillation. Front Physiol 2012; 3:296. [PMID: 22934047 PMCID: PMC3429067 DOI: 10.3389/fphys.2012.00296] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 07/08/2012] [Indexed: 01/28/2023] Open
Abstract
Understanding the mechanism of re-entrant arrhythmias in the past 30 years has allowed the development of almost curative therapies for many rhythm disturbances. The complex, polymorphic arrhythmias of atrial fibrillation (AF) and sudden death are, unfortunately, not yet well understood, and hence still in need of adequate therapy. AF contributes markedly to morbidity and mortality in aging Western populations. In the past decade, many genetically altered murine models have been described and characterized. Here, we review genetically altered murine models of AF; powerful tools that will enable a better understanding of the mechanisms of AF and the assessment of novel therapeutic interventions.
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Affiliation(s)
- Genna Riley
- Centre for Cardiovascular Sciences, School of Clinical and Experimental Medicine, University of Birmingham Birmingham, UK
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Thøgersen L, Nissen P. Flexible P-type ATPases interacting with the membrane. Curr Opin Struct Biol 2012; 22:491-9. [PMID: 22749193 DOI: 10.1016/j.sbi.2012.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 05/30/2012] [Accepted: 05/30/2012] [Indexed: 01/13/2023]
Abstract
Cation pumps and lipid flippases of the P-type ATPase family maintain electrochemical gradients and asymmetric lipid distributions across membranes, and offer significant insight of protein:membrane interactions. The sarcoplasmic reticulum Ca(2+)-ATPase features flexible and adaptive interactions with the surrounding membrane, while the Na(+),K(+)-ATPase complex is modulated by membrane components and a role for the γ-subunit as a stabilizer of a specific lipid interaction with the α-subunit has been proposed. The first crystal structure of a heavy-metal transporting ATPase shows a markedly amphipathic helix at the cytoplasmic membrane surface, highlighting this structure as a general motif of all P-type ATPases although with specialization to different membranes. Residues of central importance for the lipid flippase activity of the P4-type ATPase subfamily have been pinpointed by mutational studies, but the transport pathway and mechanism remain unknown.
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Affiliation(s)
- Lea Thøgersen
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Danish National Research Foundation, DK-8000 Aarhus C, Denmark
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Seth M, Li T, Graham V, Burch J, Finch E, Stiber JA, Rosenberg PB. Dynamic regulation of sarcoplasmic reticulum Ca(2+) stores by stromal interaction molecule 1 and sarcolipin during muscle differentiation. Dev Dyn 2012; 241:639-47. [PMID: 22411552 PMCID: PMC3306055 DOI: 10.1002/dvdy.23760] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
During muscle development, the sarco/endoplasmic reticulum (SR/ER) undergoes remodeling to establish a specialized internal Ca(2+) store for muscle contraction. We hypothesized that store operated Ca(2+) entry (SOCE) is required to fill Ca(2+) stores and is, therefore, critical to creating a mature SR/ER. Stromal interaction molecule 1 (STIM1) functions as a sensor of internal Ca(2+) store content and an activator of SOCE channels. Myocytes lacking STIM1 display reduced SR Ca(2+) content and altered expression of key SR proteins. Sarcolipin (SLN), an inhibitor of the SR calcium pump, was markedly increased in the muscle of mutant STIM1 mice. SLN opposes the actions of STIM1 by limiting SOCE, reducing SR Ca(2+) content and delaying muscle differentiation. During mouse muscle development SLN is highly expressed in embryonic muscle, while the expression of STIM1 is up-regulated postnatally. These results suggest that SOCE regulates SR/ER specialization and that SLN and STIM1 act in opposing fashions to govern SOCE during myogenesis.
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Affiliation(s)
- Malini Seth
- Department of Medicine, Duke University, Durham, North Carolina 27710, USA
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Mote KR, Gopinath T, Traaseth NJ, Kitchen J, Gor'kov PL, Brey WW, Veglia G. Multidimensional oriented solid-state NMR experiments enable the sequential assignment of uniformly 15N labeled integral membrane proteins in magnetically aligned lipid bilayers. JOURNAL OF BIOMOLECULAR NMR 2011; 51:339-346. [PMID: 21976256 DOI: 10.1007/s10858-011-9571-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 08/11/2011] [Indexed: 05/31/2023]
Abstract
Oriented solid-state NMR is the most direct methodology to obtain the orientation of membrane proteins with respect to the lipid bilayer. The method consists of measuring (1)H-(15)N dipolar couplings (DC) and (15)N anisotropic chemical shifts (CSA) for membrane proteins that are uniformly aligned with respect to the membrane bilayer. A significant advantage of this approach is that tilt and azimuthal (rotational) angles of the protein domains can be directly derived from analytical expression of DC and CSA values, or, alternatively, obtained by refining protein structures using these values as harmonic restraints in simulated annealing calculations. The Achilles' heel of this approach is the lack of suitable experiments for sequential assignment of the amide resonances. In this Article, we present a new pulse sequence that integrates proton driven spin diffusion (PDSD) with sensitivity-enhanced PISEMA in a 3D experiment ([(1)H,(15)N]-SE-PISEMA-PDSD). The incorporation of 2D (15)N/(15)N spin diffusion experiments into this new 3D experiment leads to the complete and unambiguous assignment of the (15)N resonances. The feasibility of this approach is demonstrated for the membrane protein sarcolipin reconstituted in magnetically aligned lipid bicelles. Taken with low electric field probe technology, this approach will propel the determination of sequential assignment as well as structure and topology of larger integral membrane proteins in aligned lipid bilayers.
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Affiliation(s)
- Kaustubh R Mote
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455-0431, USA
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Summermatter S, Thurnheer R, Santos G, Mosca B, Baum O, Treves S, Hoppeler H, Zorzato F, Handschin C. Remodeling of calcium handling in skeletal muscle through PGC-1α: impact on force, fatigability, and fiber type. Am J Physiol Cell Physiol 2011; 302:C88-99. [PMID: 21918181 DOI: 10.1152/ajpcell.00190.2011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regular endurance exercise remodels skeletal muscle, largely through the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). PGC-1α promotes fiber type switching and resistance to fatigue. Intracellular calcium levels might play a role in both adaptive phenomena, yet a role for PGC-1α in the adaptation of calcium handling in skeletal muscle remains unknown. Using mice with transgenic overexpression of PGC-1α, we now investigated the effect of PGC-1α on calcium handling in skeletal muscle. We demonstrate that PGC-1α induces a quantitative reduction in calcium release from the sarcoplasmic reticulum by diminishing the expression of calcium-releasing molecules. Concomitantly, maximal muscle force is reduced in vivo and ex vivo. In addition, PGC-1α overexpression delays calcium clearance from the myoplasm by interfering with multiple mechanisms involved in calcium removal, leading to higher myoplasmic calcium levels following contraction. During prolonged muscle activity, the delayed calcium clearance might facilitate force production in mice overexpressing PGC-1α. Our results reveal a novel role of PGC-1α in altering the contractile properties of skeletal muscle by modulating calcium handling. Importantly, our findings indicate PGC-1α to be both down- as well as upstream of calcium signaling in this tissue. Overall, our findings suggest that in the adaptation to chronic exercise, PGC-1α reduces maximal force, increases resistance to fatigue, and drives fiber type switching partly through remodeling of calcium transients, in addition to promoting slow-type myofibrillar protein expression and adequate energy supply.
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Affiliation(s)
- Serge Summermatter
- Biozentrum, Department of Pharmacology/Neurobiology, University of Basel, Basel, Switzerland
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Tupling AR, Bombardier E, Gupta SC, Hussain D, Vigna C, Bloemberg D, Quadrilatero J, Trivieri MG, Babu GJ, Backx PH, Periasamy M, MacLennan DH, Gramolini AO. Enhanced Ca2+ transport and muscle relaxation in skeletal muscle from sarcolipin-null mice. Am J Physiol Cell Physiol 2011; 301:C841-9. [PMID: 21697544 DOI: 10.1152/ajpcell.00409.2010] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sarcolipin (SLN) inhibits sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) pumps. To evaluate the physiological significance of SLN in skeletal muscle, we compared muscle contractility and SERCA activity between Sln-null and wild-type mice. SLN protein expression in wild-type mice was abundant in soleus and red gastrocnemius (RG), low in extensor digitorum longus (EDL), and absent from white gastrocnemius (WG). SERCA activity rates were increased in soleus and RG, but not in EDL or WG, from Sln-null muscles, compared with wild type. No differences were seen between wild-type and Sln-null EDL muscles in force-frequency curves or maximum rates of force development (+dF/dt). Maximum relaxation rates (-dF/dt) of EDL were higher in Sln-null than wild type across a range of submaximal stimulation frequencies, but not during a twitch or peak tetanic contraction. For soleus, no differences were seen between wild type and Sln-null in peak tetanic force or +dF/dt; however, force-frequency curves showed that peak force during a twitch and 10-Hz contraction was lower in Sln-null. Changes in the soleus force-frequency curve corresponded with faster rates of force relaxation at nearly all stimulation frequencies in Sln-null compared with wild type. Repeated tetanic stimulation of soleus caused increased (-dF/dt) in wild type, but not in Sln-null. No compensatory responses were detected in analysis of other Ca(2+) regulatory proteins using Western blotting and immunohistochemistry or myosin heavy chain expression using immunofluorescence. These results show that 1) SLN regulates Ca(2+)-ATPase activity thereby regulating contractile kinetics in at least some skeletal muscles, 2) the functional significance of SLN is graded to the endogenous SLN expression level, and 3) SLN inhibitory effects on SERCA function are relieved in response to repeated contractions thus enhancing relaxation rates.
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St-Amand J, Yoshioka M, Nishida Y, Tobina T, Shono N, Tanaka H. Effects of mild-exercise training cessation in human skeletal muscle. Eur J Appl Physiol 2011; 112:853-69. [DOI: 10.1007/s00421-011-2036-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 05/30/2011] [Indexed: 01/21/2023]
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Yan Z, Okutsu M, Akhtar YN, Lira VA. Regulation of exercise-induced fiber type transformation, mitochondrial biogenesis, and angiogenesis in skeletal muscle. J Appl Physiol (1985) 2010; 110:264-74. [PMID: 21030673 DOI: 10.1152/japplphysiol.00993.2010] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Skeletal muscle exhibits superb plasticity in response to changes in functional demands. Chronic increases of skeletal muscle contractile activity, such as endurance exercise, lead to a variety of physiological and biochemical adaptations in skeletal muscle, including mitochondrial biogenesis, angiogenesis, and fiber type transformation. These adaptive changes are the basis for the improvement of physical performance and other health benefits. This review focuses on recent findings in genetically engineered animal models designed to elucidate the mechanisms and functions of various signal transduction pathways and gene expression programs in exercise-induced skeletal muscle adaptations.
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Affiliation(s)
- Zhen Yan
- Department of Medicine, University of Virginia, Charlottesville, Virginia, USA.
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Physiologic basis and pathophysiologic implications of the diastolic properties of the cardiac muscle. J Biomed Biotechnol 2010; 2010:807084. [PMID: 20625419 PMCID: PMC2896897 DOI: 10.1155/2010/807084] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Revised: 02/15/2010] [Accepted: 03/21/2010] [Indexed: 12/17/2022] Open
Abstract
Although systole was for long considered the core of cardiac function, hemodynamic performance is evenly dependent on appropriate systolic and diastolic functions. The recognition that isolated diastolic dysfunction is the major culprit for approximately fifty percent of all heart failure cases imposes a deeper understanding of its underlying mechanisms so that better diagnostic and therapeutic strategies can be designed. Risk factors leading to diastolic dysfunction affect myocardial relaxation and/or its material properties by disrupting the homeostasis of cardiomyocytes as well as their relation with surrounding matrix and vascular structures. As a consequence, slower ventricular relaxation and higher myocardial stiffness may result in higher ventricular filling pressures and in the risk of hemodynamic decompensation. Thus, determining the mechanisms of diastolic function and their implications in the pathophysiology of heart failure with normal ejection fraction has become a prominent field in basic and clinical research.
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Matiello R, Fukui RT, Silva ME, Rocha DM, Wajchenberg BL, Azhar S, Santos RF. Differential regulation of PGC-1alpha expression in rat liver and skeletal muscle in response to voluntary running. Nutr Metab (Lond) 2010; 7:36. [PMID: 20433743 PMCID: PMC2874794 DOI: 10.1186/1743-7075-7-36] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 04/30/2010] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The beneficial actions of exercise training on lipid, glucose and energy metabolism and insulin sensitivity appear to be in part mediated by PGC-1alpha. Previous studies have shown that spontaneously exercised rats show at rest enhanced responsiveness to exogenous insulin, lower plasma insulin levels and increased skeletal muscle insulin sensitivity. This study was initiated to examine the functional interaction between exercise-induced modulation of skeletal muscle and liver PGC-1alpha protein expression, whole body insulin sensitivity, and circulating FFA levels as a measure of whole body fatty acid (lipid) metabolism. METHODS Two groups of male Wistar rats (2 Mo of age, 188.82 +/- 2.77 g BW) were used in this study. One group consisted of control rats placed in standard laboratory cages. Exercising rats were housed individually in cages equipped with running wheels and allowed to run at their own pace for 5 weeks. At the end of exercise training, insulin sensitivity was evaluated by comparing steady-state plasma glucose (SSPG) concentrations at constant plasma insulin levels attained during the continuous infusion of glucose and insulin to each experimental group. Subsequently, soleus and plantaris muscle and liver samples were collected and quantified for PGC-1alpha protein expression by Western blotting. Collected blood samples were analyzed for glucose, insulin and FFA concentrations. RESULTS Rats housed in the exercise wheel cages demonstrated almost linear increases in running activity with advancing time reaching to maximum value around 4 weeks. On an average, the rats ran a mean (Mean +/- SE) of 4.102 +/- 0.747 km/day and consumed significantly more food as compared to sedentary controls (P < 0.001) in order to meet their increased caloric requirement. Mean plasma insulin (P < 0.001) and FFA (P < 0.006) concentrations were lower in the exercise-trained rats as compared to sedentary controls. Mean steady state plasma insulin (SSPI) and glucose (SSPG) concentrations were not significantly different in sedentary control rats as compared to exercise-trained animals. Plantaris PGC-1alpha protein expression increased significantly from a 1.11 +/- 0.12 in the sedentary rats to 1.74 +/- 0.09 in exercising rats (P < 0.001). However, exercise had no effect on PGC-1alpha protein content in either soleus muscle or liver tissue. These results indicate that exercise training selectively up regulates the PGC-1alpha protein expression in high-oxidative fast skeletal muscle type such as plantaris muscle. CONCLUSION These data suggest that PGC-1alpha most likely plays a restricted role in exercise-mediated improvements in insulin resistance (sensitivity) and lowering of circulating FFA levels.
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Affiliation(s)
- Renata Matiello
- Laboratory of Medical Investigation, LIM-18, Division of Endocrinology and Metabolism, Hospital of Clinics, School of Medicine, University of Sao Paulo, Av Dr Arnaldo, 455, 3rd floor, room 3324, Sao Paulo, 01246-903, Brazil.
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Vasu VT, Ott S, Hobson B, Rashidi V, Oommen S, Cross CE, Gohil K. Sarcolipin and ubiquitin carboxy-terminal hydrolase 1 mRNAs are over-expressed in skeletal muscles of alpha-tocopherol deficient mice. Free Radic Res 2009; 43:106-16. [PMID: 19204867 DOI: 10.1080/10715760802616676] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The transcriptome of ataxic muscles from alpha-tocopherol transfer protein deficient (ATTP-KO), 23-month old, mice was compared with that of their normal littermates. Genes encoding sarcolipin (sln) and ubiquitin carboxyl-terminal hydrolase (uchl1) were over-expressed (> or =10-fold) in ataxic muscles. SLN is a 3.2 kDa membrane protein that binds to sarcoplasmic reticulum calcium ATPase, regulates Ca(+ +) transport and muscle relaxation-contraction cycles. UCHL1 is a 24.8 kDa member of proteosome proteins; it is over-expressed in myofibrillar myopathy and is associated with neurodegenerative diseases. Furthermore, six additional transcripts, three encoding thin-filament proteins and three encoding Ca(+ +) sensing proteins that participate in contraction-relaxation cycle, and eight transcripts that encode members of lysosomal proteins were also over-expressed in ataxic muscles. These observations suggest that chronic alpha-tocopherol (AT) deficiency activates critical genes of muscle contractility and protein degradation pathways, simultaneously. The magnitude of induction of sln and uchl1 was lower in asymptomatic, 8-month old, ATTP-KO mice and in 8-month old mice fed an AT-depleted diet. These studies suggest sln and uchl1 genes as novel targets of AT deficiency and may offer molecular correlates of well documented descriptions of neuromuscular dysfunctions in AT-deficient rodents. Since the neuromuscular deficits of ATTP-KO mice appear to be similar to those of patients with ATTP mutations, it is suggested that over-expression of sln and uchl1 may also contribute to AT-sensitive ataxia in humans.
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Affiliation(s)
- Vihas T Vasu
- Department of Internal Medicine, University of California, Davis, 95616, USA
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Ottenheijm CAC, Hidalgo C, Rost K, Gotthardt M, Granzier H. Altered contractility of skeletal muscle in mice deficient in titin's M-band region. J Mol Biol 2009; 393:10-26. [PMID: 19683008 DOI: 10.1016/j.jmb.2009.08.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 08/06/2009] [Accepted: 08/07/2009] [Indexed: 12/19/2022]
Abstract
We investigated the contractile phenotype of skeletal muscle deficient in exons MEx1 and MEx2 (KO) of the titin M-band by using the cre-lox recombination system and a multidisciplinary physiological approach to study skeletal muscle contractile performance. At a maximal tetanic stimulation frequency, intact KO extensor digitorum longus muscle was able to produce wild-type levels of force. However, at submaximal stimulation frequency, force was reduced in KO mice, giving rise to a rightward shift of the force-frequency curve. This rightward shift of the force-frequency curve could not be explained by altered sarcoplasmic reticulum Ca(2+) handling, as indicated by analysis of Ca(2+) transients in intact myofibers and expression of Ca(2)(+)-handling proteins, but can be explained by the reduced myofilament Ca(2+) sensitivity of force generation that we found. Western blotting experiments suggested that the excision of titin exons MEx1 and MEx2 did not result in major changes in expression of titin M-band binding proteins or phosphorylation level of the thin-filament regulatory proteins, but rather in a shift toward expression of slow isoforms of the thick-filament-associated protein, myosin binding protein-C. Extraction of myosin binding protein-C from skinned muscle normalized myofilament Ca(2+) sensitivity of the KO extensor digitorum longus muscle. Thus, our data suggest that the M-band region of titin affects the expression of genes involved in the regulation of skeletal muscle contraction.
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Affiliation(s)
- Coen A C Ottenheijm
- Department of Physiology, Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85724, USA
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Tupling AR. The decay phase of Ca2+ transients in skeletal muscle: regulation and physiologyThis paper is one of a selection of papers published in this Special Issue, entitled 14th International Biochemistry of Exercise Conference – Muscles as Molecular and Metabolic Machines, and has undergone the Journal’s usual peer review process. Appl Physiol Nutr Metab 2009; 34:373-6. [DOI: 10.1139/h09-033] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cytosolic Ca2+ transients associated with contraction and relaxation cycles in skeletal muscle are primarily dependent on the kinetics of Ca2+ release and Ca2+ uptake by the sarcoplasmic reticulum (SR). In humans, sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs) are solely responsible for the removal of Ca2+ from the cytosol following muscle contraction. There are several signalling systems involved in the acute regulation of SERCAs required to achieve a given Ca2+ transient during muscle contraction–relaxation cycles. Cyclic-AMP-dependent protein kinase and Ca2+/calmodulin-dependent protein kinase signalling activate SERCAs through the regulation of the endogenous SERCA-regulatory proteins, phospholamban and sarcolipin, both of which are highly expressed in human skeletal muscle. Recent studies on the regulation of SERCA2b in arterial smooth muscle and work from my laboratory on the interaction between SERCAs and the inducible 70-kDa heat shock protein suggests a novel role for redox signalling in regulating SERCA activity. In the absence of fatigue, activation of these signalling systems in response to repeated muscle activity serves to increase the rate of cytosolic free Ca2+ ([Ca2+]f) decay (i.e., SR Ca2+ uptake) and the speed of muscle relaxation.
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Affiliation(s)
- A. Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada (e-mail: )
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Marotta M, Ruiz-Roig C, Sarria Y, Peiro JL, Nuñez F, Ceron J, Munell F, Roig-Quilis M. Muscle genome-wide expression profiling during disease evolution in mdx mice. Physiol Genomics 2009; 37:119-32. [DOI: 10.1152/physiolgenomics.90370.2008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mdx mice show a milder phenotype than Duchenne patients despite bearing an analogous genetic defect. Our aim was to sort out genes, differentially expressed during the evolution of skeletal muscle mdx mouse disease, to elucidate the mechanisms by which these animals overcome the lack of dystrophin. Genome-wide microarray-based gene expression analysis was carried out at 3 wk and 1.5 and 3 mo of life. Candidate genes were selected by comparing: 1) mdx vs. controls at each point in time, and 2) mdx mice and 3) control mice among the three points in time. The first analysis showed a strong upregulation (96%) of inflammation-related genes and in >75% of genes related to cell adhesion, muscle structure/regeneration, and extracellular matrix remodeling during mdx disease evolution. Lgals3, Postn, Ctss, and Sln genes showed the strongest variations. The analysis performed among points in time demonstrated significant changes in Ecm1, Spon1, Thbs1, Csrp3, Myo10, Pde4b, and Adamts-5 exclusively during mdx mice lifespan. RT-PCR analysis of Postn, Sln, Ctss, Thbs1, Ecm1, and Adamts-5 expression from 3 wk to 9 mo, confirmed microarray data and demonstrated variations beyond 3 mo of age. A high-confidence functional network analysis demonstrated a strong relationship between them and showed two main subnetworks, having Dmd- Utrn- Myo10 and Adamts5- Thbs1- Spon1-Postn as principal nodes, which are functionally linked to Abca1, Actn4, Crebbp, Csrp3, Lama1, Lama3, Mical2, Mical3, Myf6, Pxn, and Sparc genes. Candidate genes may participate in the decline of muscle necrosis in mdx mice and could be considered potential therapeutic targets for Duchenne patients.
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Affiliation(s)
- Mario Marotta
- Laboratori de Neurologia Infantil, Institut de Recerca, Barcelona, Spain
| | - Claudia Ruiz-Roig
- Laboratori de Neurologia Infantil, Institut de Recerca, Barcelona, Spain
| | - Yaris Sarria
- Laboratori de Neurologia Infantil, Institut de Recerca, Barcelona, Spain
| | - Jose Luis Peiro
- Unitat de Cirurgia Fetal i Neonatal, Departament de Cirurgia Pediàtrica, Barcelona, Spain
| | - Fatima Nuñez
- Unitat Cientifico-Tecnica de Suport (UCTS), Institut de Recerca, Barcelona, Spain
| | - Julian Ceron
- Genetics and Functional Genomics Group, Molecular Biology and Biochemistry Research Center for Nanomedicine (CIBBIM), Barcelona, Spain
| | - Francina Munell
- Unitat de Recerca Biomedica, Institut de Recerca, Barcelona, Spain
| | - Manuel Roig-Quilis
- Laboratori de Neurologia Infantil, Institut de Recerca, Barcelona, Spain
- Secció de Neurologia Infantil, Hospital Materno-Infantil, Hospital Universitari Vall d'Hebron, Barcelona, Spain
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50
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Rigoard P, Buffenoir K, Wager M, Bauche S, Giot JP, Lapierre F. [Molecular architecture of the sarcoplasmic reticulum and its role in the ECC]. Neurochirurgie 2009; 55 Suppl 1:S83-91. [PMID: 19233437 DOI: 10.1016/j.neuchi.2008.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 05/09/2008] [Indexed: 11/16/2022]
Abstract
The sarcoplasmic reticulum (SR) plays a fundamental role in excitation-contraction coupling, which propagates the electric signal conversion along the muscle fiber's plasmic membrane to a mechanical event manifested as a muscle contraction. It plays a crucial role in calcium homeostasis and intracellular calcium storage control (storage, liberation and uptake) necessary for fiber muscle contraction and then relaxation. These functions take place at the triad, made up of individualized SR subdomains where the protein-specific organization provides efficient and fast coupling. Ryanodine receptors (RyR) and dihydropyridine receptors (DHPR) mainly act in calcium exchanges in the SR. This particular structural and molecular architecture must be correlated to its functional specificity.
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Affiliation(s)
- P Rigoard
- Service de neurochirurgie, CHU La Milétrie, 2, rue de la Milétrie, BP 577, 86021 Poitiers cedex, France.
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