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Armanious GP, Lemieux MJ, Espinoza-Fonseca LM, Young HS. Missense variants in phospholamban and cardiac myosin binding protein identified in patients with a family history and clinical diagnosis of dilated cardiomyopathy. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119699. [PMID: 38387507 DOI: 10.1016/j.bbamcr.2024.119699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 11/07/2023] [Accepted: 02/15/2024] [Indexed: 02/24/2024]
Abstract
As the genetic landscape of cardiomyopathies continues to expand, the identification of missense variants in disease-associated genes frequently leads to a classification of variant of uncertain significance (VUS). For the proper reclassification of such variants, functional characterization is an important contributor to the proper assessment of pathogenic potential. Several missense variants in the calcium transport regulatory protein phospholamban have been associated with dilated cardiomyopathy. However, >40 missense variants in this transmembrane peptide are currently known and most remain classified as VUS with little clinical information. Similarly, missense variants in cardiac myosin binding protein have been associated with hypertrophic cardiomyopathy. However, hundreds of variants are known and many have low penetrance and are often found in control populations. Herein, we focused on novel missense variants in phospholamban, an Ala15-Thr variant found in a 4-year-old female and a Pro21-Thr variant found in a 60-year-old female, both with a family history and clinical diagnosis of dilated cardiomyopathy. The patients also harbored a Val896-Met variant in cardiac myosin binding protein. The phospholamban variants caused defects in the function, phosphorylation, and dephosphorylation of this calcium transport regulatory peptide, and we classified these variants as potentially pathogenic. The variant in cardiac myosin binding protein alters the structure of the protein. While this variant has been classified as benign, it has the potential to be a low-risk susceptibility variant because of the structural change in cardiac myosin binding protein. Our studies provide new biochemical evidence for missense variants previously classified as benign or VUS.
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Affiliation(s)
- Gareth P Armanious
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - L Michel Espinoza-Fonseca
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Howard S Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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2
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Stoikos J, Kurgan N, Kottaras S, Fajardo VA, Gittings W, Klentrou P. Effects of sclerostin injection on soleus and extensor digitorum longus muscle tissue in male mice. Can J Physiol Pharmacol 2024; 102:293-304. [PMID: 37976473 DOI: 10.1139/cjpp-2023-0268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Sclerostin, a potent inhibitor of the Wnt signaling pathway, plays a critical role in bone homeostasis. Evidence suggests that sclerostin may also be involved in crosstalk between other tissues, including muscle. This pilot study attempted to examine the effects of sclerostin on soleus and extensor digitorum longus (EDL) muscle tissue from male mice that were given continuous recombinant sclerostin injections for 4 weeks. A total of 48 10-week-old male C57BL/6J mice were assigned to be sedentary or perform 1 h treadmill running per day for 4 weeks and administered subcutaneous injections of either saline or recombinant sclerostin 5 days/week. Sclerostin injection led to a reduction in the soleus myosin heavy chain (MHC) I, MHC I/IIA, MHC IIA/X, and MHC IIB cross-sectional area (p < 0.05) with no exercise effects on these reductions. In contrast, there were no effects of sclerostin injections or exercise on the fast-twitch EDL muscle in terms of size, MHC protein, or markers of Wnt signaling. These findings provide preliminary evidence of sclerostin's endocrine role in muscle via decreases in myofiber cross-sectional area, which seems to be independent of fiber type but muscle type-specific. More studies, however, are needed to confirm these preliminary results.
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Affiliation(s)
- Joshua Stoikos
- Centre for Bone and Muscle Health, Department of Kinesiology, Brock University, ON, Canada
| | - Nigel Kurgan
- Centre for Bone and Muscle Health, Department of Kinesiology, Brock University, ON, Canada
| | - Steven Kottaras
- Centre for Bone and Muscle Health, Department of Kinesiology, Brock University, ON, Canada
| | - Val A Fajardo
- Centre for Bone and Muscle Health, Department of Kinesiology, Brock University, ON, Canada
| | - William Gittings
- Centre for Bone and Muscle Health, Department of Kinesiology, Brock University, ON, Canada
| | - Panagiota Klentrou
- Centre for Bone and Muscle Health, Department of Kinesiology, Brock University, ON, Canada
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3
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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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4
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da Silva HNM, Mizobuti DS, Pereira VA, da Rocha GL, da Cruz MV, de Oliveira AG, Silveira LR, Minatel E. LED therapy plus idebenone treatment targeting calcium and mitochondrial signaling pathways in dystrophic muscle cells. Cell Stress Chaperones 2023; 28:773-785. [PMID: 37578579 PMCID: PMC10746663 DOI: 10.1007/s12192-023-01369-2] [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: 05/17/2023] [Revised: 07/20/2023] [Accepted: 08/07/2023] [Indexed: 08/15/2023] Open
Abstract
Intracellular calcium dysregulation, oxidative stress, and mitochondrial dysfunction are some of the main pathway contributors towards disease progression in Duchenne muscular dystrophy (DMD). This study is aimed at investigating the effects of light emitting diode therapy (LEDT) and idebenone antioxidant treatment, applied alone or together in dystrophic primary muscle cells from mdx mice, the experimental model of DMD. Mdx primary muscle cells were submitted to LEDT and idebenone treatment and evaluated for cytotoxic effects and calcium and mitochondrial signaling pathways. LEDT and idebenone treatment showed no cytotoxic effects on the dystrophic muscle cells. Regarding the calcium pathways, after LEDT and idebenone treatment, a significant reduction in intracellular calcium content, calpain-1, calsequestrin, and sarcolipin levels, was observed. In addition, a significant reduction in oxidative stress level markers, such as H2O2, and 4-HNE levels, was observed. Regarding mitochondrial signaling pathways, a significant increase in oxidative capacity (by OCR and OXPHOS levels) was observed. In addition, the PGC-1α, SIRT-1, and PPARδ levels were significantly higher in the LEDT plus idebenone treated-dystrophic muscle cells. Together, the findings suggest that LEDT and idebenone treatment, alone or in conjunction, can modulate the calcium and mitochondrial signaling pathways, such as SLN, SERCA 1, and PGC-1α, contributing towards the improvement of the dystrophic phenotype in mdx muscle cells. In addition, data from the LEDT plus idebenone treatment showed slightly better results than those of each separate treatment in terms of SLN, OXPHOS, and SIRT-1.
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Affiliation(s)
| | - Daniela Sayuri Mizobuti
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Valéria Andrade Pereira
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Guilherme Luiz da Rocha
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Marcos Vinícius da Cruz
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
- Obesity and Comorbidities Research Center (OCRC), Campinas, Brazil
| | - André Gustavo de Oliveira
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
- Obesity and Comorbidities Research Center (OCRC), Campinas, Brazil
| | - Leonardo Reis Silveira
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
- Obesity and Comorbidities Research Center (OCRC), Campinas, Brazil
| | - Elaine Minatel
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil.
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Dowling P, Swandulla D, Ohlendieck K. Biochemical and proteomic insights into sarcoplasmic reticulum Ca 2+-ATPase complexes in skeletal muscles. Expert Rev Proteomics 2023; 20:125-142. [PMID: 37668143 DOI: 10.1080/14789450.2023.2255743] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 07/07/2023] [Accepted: 08/14/2023] [Indexed: 09/06/2023]
Abstract
INTRODUCTION Skeletal muscles contain large numbers of high-molecular-mass protein complexes in elaborate membrane systems. Integral membrane proteins are involved in diverse cellular functions including the regulation of ion handling, membrane homeostasis, energy metabolism and force transmission. AREAS COVERED The proteomic profiling of membrane proteins and large protein assemblies in skeletal muscles are outlined in this article. This includes a critical overview of the main biochemical separation techniques and the mass spectrometric approaches taken to study membrane proteins. As an illustrative example of an analytically challenging large protein complex, the proteomic detection and characterization of the Ca2+-ATPase of the sarcoplasmic reticulum is discussed. The biological role of this large protein complex during normal muscle functioning, in the context of fiber type diversity and in relation to mechanisms of physiological adaptations and pathophysiological abnormalities is evaluated from a proteomics perspective. EXPERT OPINION Mass spectrometry-based muscle proteomics has decisively advanced the field of basic and applied myology. Although it is technically challenging to study membrane proteins, innovations in protein separation methodology in combination with sensitive mass spectrometry and improved systems bioinformatics has allowed the detailed proteomic detection and characterization of skeletal muscle membrane protein complexes, such as Ca2+-pump proteins of the sarcoplasmic reticulum.
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Affiliation(s)
- Paul Dowling
- Department of Biology, Maynooth University, National University of Ireland, Maynooth Kildare, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth Kildare, Ireland
| | - Dieter Swandulla
- Institute of Physiology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, Maynooth Kildare, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth Kildare, Ireland
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Zanotti S, Ripolone M, Napoli L, Velardo D, Salani S, Ciscato P, Priori S, Kukavica D, Mazzanti A, Diamanti L, Vegezzi E, Moggio M, Corti S, Comi G, Sciacco M. Characterization of Skeletal Muscle Biopsy and Derived Myoblasts in a Patient Carrying Arg14del Mutation in Phospholamban Gene. Cells 2023; 12:1405. [PMID: 37408239 DOI: 10.3390/cells12101405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/10/2023] [Accepted: 05/15/2023] [Indexed: 07/07/2023] Open
Abstract
Phospholamban is involved in the regulation of the activity and storage of calcium in cardiac muscle. Several mutations have been identified in the PLN gene causing cardiac disease associated with arrhythmogenic and dilated cardiomyopathy. The patho-mechanism underlying PLN mutations is not fully understood and a specific therapy is not yet available. PLN mutated patients have been deeply investigated in cardiac muscle, but very little is known about the effect of PLN mutations in skeletal muscle. In this study, we investigated both histological and functional features in skeletal muscle tissue and muscle-derived myoblasts from an Italian patient carrying the Arg14del mutation in PLN. The patient has a cardiac phenotype, but he also reported lower limb fatigability, cramps and fasciculations. The evaluation of a skeletal muscle biopsy showed histological, immunohistochemical and ultrastructural alterations. In particular, we detected an increase in the number of centronucleated fibers and a reduction in the fiber cross sectional area, an alteration in p62, LC3 and VCP proteins and the formation of perinuclear aggresomes. Furthermore, the patient's myoblasts showed a greater propensity to form aggresomes, even more marked after proteasome inhibition compared with control cells. Further genetic and functional studies are necessary to understand whether a definition of PLN myopathy, or cardiomyopathy plus, can be introduced for selected cases with clinical evidence of skeletal muscle involvement. Including skeletal muscle examination in the diagnostic process of PLN-mutated patients can help clarify this issue.
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Affiliation(s)
- Simona Zanotti
- Neuromuscular and Rare Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Michela Ripolone
- Neuromuscular and Rare Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Laura Napoli
- Neuromuscular and Rare Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Daniele Velardo
- Neuromuscular and Rare Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Sabrina Salani
- Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Patrizia Ciscato
- Neuromuscular and Rare Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Silvia Priori
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
- Department of Molecular Cardiology, IRCCS ICS Maugeri, 27100 Pavia, Italy
- Laboratory of Molecular Cardiology, Centro Nacional de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain
| | - Deni Kukavica
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
- Department of Molecular Cardiology, IRCCS ICS Maugeri, 27100 Pavia, Italy
- Laboratory of Molecular Cardiology, Centro Nacional de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain
| | - Andrea Mazzanti
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
- Department of Molecular Cardiology, IRCCS ICS Maugeri, 27100 Pavia, Italy
- Laboratory of Molecular Cardiology, Centro Nacional de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain
| | - Luca Diamanti
- Neuroncology Unit, IRCCS Mondino Foundation, 27100 Pavia, Italy
| | - Elisa Vegezzi
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy
- IRCCS Mondino Foundation, 27100 Pavia, Italy
| | - Maurizio Moggio
- Neuromuscular and Rare Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Stefania Corti
- Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
- Dino Ferrari Centre, Department of Pathophysiology and Transplantation (DEPT), University of Milan, 20122 Milan, Italy
| | - Giacomo Comi
- Neuromuscular and Rare Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
- Dino Ferrari Centre, Department of Pathophysiology and Transplantation (DEPT), University of Milan, 20122 Milan, Italy
| | - Monica Sciacco
- Neuromuscular and Rare Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
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7
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Zádor E. The Meeting of Micropeptides with Major Ca 2+ Pumps in Inner Membranes-Consideration of a New Player, SERCA1b. MEMBRANES 2023; 13:274. [PMID: 36984661 PMCID: PMC10058886 DOI: 10.3390/membranes13030274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/20/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Calcium is a major signalling bivalent cation within the cell. Compartmentalization is essential for regulation of calcium mediated processes. A number of players contribute to intracellular handling of calcium, among them are the sarco/endoplasmic reticulum calcium ATP-ases (SERCAs). These molecules function in the membrane of ER/SR pumping Ca2+ from cytoplasm into the lumen of the internal store. Removal of calcium from the cytoplasm is essential for signalling and for relaxation of skeletal muscle and heart. There are three genes and over a dozen isoforms of SERCA in mammals. These can be potentially influenced by small membrane peptides, also called regulins. The discovery of micropeptides has increased in recent years, mostly because of the small ORFs found in long RNAs, annotated formerly as noncoding (lncRNAs). Several excellent works have analysed the mechanism of interaction of micropeptides with each other and with the best known SERCA1a (fast muscle) and SERCA2a (heart, slow muscle) isoforms. However, the array of tissue and developmental expressions of these potential regulators raises the question of interaction with other SERCAs. For example, the most abundant calcium pump in neonatal and regenerating skeletal muscle, SERCA1b has never been looked at with scrutiny to determine whether it is influenced by micropeptides. Further details might be interesting on the interaction of these peptides with the less studied SERCA1b isoform.
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Affiliation(s)
- Ernő Zádor
- Institute of Biochemistry, Albert Szent-Györgyi Faculty of Medicine, University of Szeged, Dóm tér 9, H-6720 Szeged, Hungary
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Sarver DC, Xu C, Rodriguez S, Aja S, Jaffe AE, Gao FJ, Delannoy M, Periasamy M, Kazuki Y, Oshimura M, Reeves RH, Wong GW. Hypermetabolism in mice carrying a near complete human chromosome 21. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526183. [PMID: 36778465 PMCID: PMC9915508 DOI: 10.1101/2023.01.30.526183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The consequences of aneuploidy have traditionally been studied in cell and animal models in which the extrachromosomal DNA is from the same species. Here, we explore a fundamental question concerning the impact of aneuploidy on systemic metabolism using a non-mosaic transchromosomic mouse model (TcMAC21) carrying a near complete human chromosome 21. Independent of diets and housing temperatures, TcMAC21 mice consume more calories, are hyperactive and hypermetabolic, remain consistently lean and profoundly insulin sensitive, and have a higher body temperature. The hypermetabolism and elevated thermogenesis are due to sarcolipin overexpression in the skeletal muscle, resulting in futile sarco(endo)plasmic reticulum Ca 2+ ATPase (SERCA) activity and energy dissipation. Mitochondrial respiration is also markedly increased in skeletal muscle to meet the high ATP demand created by the futile cycle. This serendipitous discovery provides proof-of-concept that sarcolipin-mediated thermogenesis via uncoupling of the SERCA pump can be harnessed to promote energy expenditure and metabolic health.
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Affiliation(s)
- Dylan C. Sarver
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Cheng Xu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Susana Rodriguez
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Susan Aja
- Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Andrew E. Jaffe
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.,The Lieber Institute for Brain Development, Baltimore, MD, USA.,Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA.,Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Feng J. Gao
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Michael Delannoy
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Muthu Periasamy
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA.,Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Yasuhiro Kazuki
- Division of Genome and Cellular Functions, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, Tottori, Japan,Chromosome Engineering Research Center, Tottori University, Tottori, Japan
| | - Mitsuo Oshimura
- Chromosome Engineering Research Center, Tottori University, Tottori, Japan
| | - Roger H. Reeves
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - G. William Wong
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Correspondence:
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9
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Skeletal and cardiac muscle calcium transport regulation in health and disease. Biosci Rep 2022; 42:232141. [PMID: 36413081 DOI: 10.1042/bsr20211997] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/04/2022] [Accepted: 11/22/2022] [Indexed: 11/23/2022] Open
Abstract
In healthy muscle, the rapid release of calcium ions (Ca2+) with excitation-contraction (E-C) coupling, results in elevations in Ca2+ concentrations which can exceed 10-fold that of resting values. The sizable transient changes in Ca2+ concentrations are necessary for the activation of signaling pathways, which rely on Ca2+ as a second messenger, including those involved with force generation, fiber type distribution and hypertrophy. However, prolonged elevations in intracellular Ca2+ can result in the unwanted activation of Ca2+ signaling pathways that cause muscle damage, dysfunction, and disease. Muscle employs several calcium handling and calcium transport proteins that function to rapidly return Ca2+ concentrations back to resting levels following contraction. This review will detail our current understanding of calcium handling during the decay phase of intracellular calcium transients in healthy skeletal and cardiac muscle. We will also discuss how impairments in Ca2+ transport can occur and how mishandling of Ca2+ can lead to the pathogenesis and/or progression of skeletal muscle myopathies and cardiomyopathies.
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10
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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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11
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Geromella MS, Ryan CR, Braun JL, Finch MS, Maddalena LA, Bagshaw O, Hockey BL, Moradi F, Fenech RK, Ryoo J, Marko DM, Dhaliwal R, Sweezey-Munroe J, Hamstra SI, Gardner G, Silvera S, Vandenboom R, Roy BD, Stuart JA, MacPherson RE, Fajardo VA. Low-dose lithium supplementation promotes adipose tissue browning and sarco(endo)plasmic reticulum Ca2+ ATPase uncoupling in muscle. J Biol Chem 2022; 298:102568. [DOI: 10.1016/j.jbc.2022.102568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/11/2022] Open
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12
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Natural Polyphenols as SERCA Activators: Role in the Endoplasmic Reticulum Stress-Related Diseases. Molecules 2022; 27:molecules27165095. [PMID: 36014327 PMCID: PMC9415898 DOI: 10.3390/molecules27165095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 11/17/2022] Open
Abstract
Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) is a key protein responsible for transporting Ca2+ ions from the cytosol into the lumen of the sarco/endoplasmic reticulum (SR/ER), thus maintaining Ca2+ homeostasis within cells. Accumulating evidence suggests that impaired SERCA function is associated with disruption of intracellular Ca2+ homeostasis and induction of ER stress, leading to different chronic pathological conditions. Therefore, appropriate strategies to control Ca2+ homeostasis via modulation of either SERCA pump activity/expression or relevant signaling pathways may represent a useful approach to combat pathological states associated with ER stress. Natural dietary polyphenolic compounds, such as resveratrol, gingerol, ellagic acid, luteolin, or green tea polyphenols, with a number of health-promoting properties, have been described either to increase SERCA activity/expression directly or to affect Ca2+ signaling pathways. In this review, potential Ca2+-mediated effects of the most studied polyphenols on SERCA pumps or related Ca2+ signaling pathways are summarized, and relevant mechanisms of their action on Ca2+ regulation with respect to various ER stress-related states are depicted. All data were collected using scientific search tools (i.e., Science Direct, PubMed, Scopus, and Google Scholar).
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13
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Nemirovskaya TL, Sharlo KA. Roles of ATP and SERCA in the Regulation of Calcium Turnover in Unloaded Skeletal Muscles: Current View and Future Directions. Int J Mol Sci 2022; 23:ijms23136937. [PMID: 35805949 PMCID: PMC9267070 DOI: 10.3390/ijms23136937] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 06/20/2022] [Indexed: 11/16/2022] Open
Abstract
A decrease in skeletal muscle contractile activity or its complete cessation (muscle unloading or disuse) leads to muscle fibers’ atrophy and to alterations in muscle performance. These changes negatively affect the quality of life of people who, for one reason or another, are forced to face a limitation of physical activity. One of the key regulatory events leading to the muscle disuse-induced changes is an impairment of calcium homeostasis, which leads to the excessive accumulation of calcium ions in the sarcoplasm. This review aimed to analyze the triggering mechanisms of calcium homeostasis impairment (including those associated with the accumulation of high-energy phosphates) under various types of muscle unloading. Here we proposed a hypothesis about the regulatory mechanisms of SERCA and IP3 receptors activity during muscle unloading, and about the contribution of these mechanisms to the excessive calcium ion myoplasmic accumulation and gene transcription regulation via excitation–transcription coupling.
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14
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Tripp TR, Frankish BP, Lun V, Wiley JP, Shearer J, Murphy RM, MacInnis MJ. Time course and fibre type-dependent nature of calcium-handling protein responses to sprint interval exercise in human skeletal muscle. J Physiol 2022; 600:2897-2917. [PMID: 35556249 DOI: 10.1113/jp282739] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/22/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Sprint interval training (SIT) has been shown to cause fragmentation of the sarcoplasmic reticulum calcium-release channel, ryanodine receptor 1 (RyR1) 24 hours post-exercise, which may act as a signal for mitochondrial biogenesis. In this study, we examined the time course of RyR1 fragmentation in human whole muscle and pooled type I and type II skeletal muscle fibres following a single session of SIT. Full-length RyR1 protein content was significantly lower than pre-exercise by 6 h post-SIT in whole muscle, and fragmentation was detectable in type II but not type I fibres, though to a lesser extent than in whole muscle. The peak in PGC1A mRNA expression occurred earlier than RyR1 fragmentation. The increased temporal resolution and fibre type-specific responses for RyR1 fragmentation provide insights into its importance to mitochondrial biogenesis in humans. ABSTRACT Sprint interval training (SIT) causes fragmentation of the skeletal muscle sarcoplasmic reticulum Ca2+ release channel, ryanodine receptor 1 (RyR1), 24h post-exercise, potentially signaling mitochondrial biogenesis by increasing cytosolic [Ca2+ ]. Yet, the time course and skeletal muscle fibre type-specific patterns of RyR1 fragmentation following a session of SIT remain unknown. Ten participants (n = 4 females; n = 6 males) performed a session of SIT (6 × 30 s "all-out" with 4.5 min rest after each sprint) with vastus lateralis muscle biopsy samples collected before and 3, 6, and 24h after exercise. In whole muscle, full-length RyR1 protein content was significantly reduced 6 h (mean [SD]; -38 [38]%; p<0.05) and 24 h post-SIT (-30 [48]%; p<0.05) compared to pre-exercise. Examining each participant's largest response in pooled samples, full-length RyR1 protein content was reduced in type II (-26 [30]%; p<0.05) but not type I fibres (-11 [40]%; p>0.05). 3h post-SIT, there was also a decrease in SERCA1 in type II fibres (-23 [17]%; p<0.05) and SERCA2a in type I fibres (-19 [21]%; p<0.05), despite no time effect for either protein in whole muscle samples (p>0.05). PGC1A mRNA content was elevated 3h and 6h post-SIT (5.3- and 3.7-fold change from pre, respectively; p<0.05 for both), but peak PGC1A mRNA expression was not significantly correlated with peak RyR1 fragmentation (r2 = 0.10; p>0.05). In summary, altered Ca2+ -handling protein expression, which occurs primarily in type II muscle fibres, may influence signals for mitochondrial biogenesis as early as 3-6 h post-SIT in humans. Abstract figure legend Western blotting was performed on whole muscle and pooled type I and II muscle fibre preparations derived from human vastus lateralis muscle biopsy samples collected before and after a single session of sprint interval training (SIT). Full-length ryanodine receptor 1 (RyR1) protein content was reduced 6 and 24 h post-exercise in whole muscle samples compared to baseline, despite a heterogeneous time course among individuals. This RyR1 fragmentation proceeded and outlasted the increase in peroxisome proliferator-activated γ receptor coactivator 1α (PGC1A) mRNA expression. When examining the time point of each individual's peak response, RyR1 fragmentation was evident in type II, but not type I, muscle fibres. These findings suggest that, in humans, mitochondrial biogenesis could be influenced by RyR1 fragmentation 3-6 h post-SIT in a fibre type-dependent manner. Created with BioRender.com. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Barnaby P Frankish
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia
| | - Victor Lun
- University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - J Preston Wiley
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jane Shearer
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robyn M Murphy
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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15
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Davoli R, Vegni J, Cesarani A, Dimauro C, Zappaterra M, Zambonelli P. Identification of differentially expressed genes in early-postmortem Semimembranosus muscle of Italian Large White heavy pigs divergent for glycolytic potential. Meat Sci 2022; 187:108754. [DOI: 10.1016/j.meatsci.2022.108754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 01/18/2022] [Accepted: 02/01/2022] [Indexed: 10/19/2022]
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16
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Ca 2+ leak through ryanodine receptor 1 regulates thermogenesis in resting skeletal muscle. Proc Natl Acad Sci U S A 2022; 119:2119203119. [PMID: 35046046 PMCID: PMC8794839 DOI: 10.1073/pnas.2119203119] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2021] [Indexed: 11/26/2022] Open
Abstract
The evolution of mammals to use skeletal muscle as a source of heat allowed them to spread to all parts of the globe. The generation of heat requires increased adenosine triphosphate (ATP) hydrolysis in the resting muscle in a regulated manner, but how this mechanism works is unknown. The results suggest that mammals increase their RyR1 Ca2+ leak rate to amplify a basal ATP turnover rate at the sarcoplasmic reticulum Ca2+ pump that is higher than that of lower vertebrates. Muscle-based thermogenesis allows regulation of body temperature that is essential for life in mammals and provides a potential pathway for manipulating body weight or temperature by altering metabolic rate. Mammals rely on nonshivering thermogenesis (NST) from skeletal muscle so that cold temperatures can be tolerated. NST results from activity of the sarcoplasmic reticulum (SR) Ca2+ pump in skeletal muscle, but the mechanisms that regulate this activity are unknown. Here, we develop a single-fiber assay to investigate the role of Ca2+ leak through ryanodine receptor 1 (RyR1) to generate heat at the SR Ca2+ pump in resting muscle. By inhibiting a subpopulation of RyR1s in a single-fiber preparation via targeted delivery of ryanodine through transverse tubules, we achieve in-preparation isolation of RyR1 Ca2+ leak. This maneuver provided a critical increase in signal-to-noise of the SR-temperature-sensitive dye ER thermoyellow fluorescence signal from the fiber to allow detection of SR temperature changes as either RyR1 or SR Ca2+ pump activity was altered. We found that RyR1 Ca2+ leak raises cytosolic [Ca2+] in the local vicinity of the SR Ca2+ pump to amplify thermogenesis. Furthermore, gene-dose-dependent increases in RyR1 leak in RYR1 mutant mice result in progressive rises in leak-dependent heat, consistent with raised local [Ca2+] at the SR Ca2+ pump via RyR1 Ca2+ leak. We also show that basal RyR Ca2+ leak and the heat generated by the SR Ca2+ pump in the absence of RyR Ca2+ leak is greater in fibers from mice than from toads. The distinct function of RyRs and SR Ca2+ pump in endothermic mammals compared to ectothermic amphibians provides insights into the mechanisms by which mammalian skeletal muscle achieves thermogenesis at rest.
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17
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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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18
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Sarcoplasmic Reticulum from Horse Gluteal Muscle Is Poised for Enhanced Calcium Transport. Vet Sci 2021; 8:vetsci8120289. [PMID: 34941816 PMCID: PMC8705379 DOI: 10.3390/vetsci8120289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/02/2021] [Accepted: 11/17/2021] [Indexed: 11/16/2022] Open
Abstract
We have analyzed the enzymatic activity of the sarcoplasmic reticulum (SR) Ca2+-transporting ATPase (SERCA) from the horse gluteal muscle. Horses are bred for peak athletic performance yet exhibit a high incidence of exertional rhabdomyolysis, with elevated levels of cytosolic Ca2+ proposed as a correlative linkage. We recently reported an improved protocol for isolating SR vesicles from horse muscle; these horse SR vesicles contain an abundant level of SERCA and only trace-levels of sarcolipin (SLN), the inhibitory peptide subunit of SERCA in mammalian fast-twitch skeletal muscle. Here, we report that the in vitro Ca2+ transport rate of horse SR vesicles is 2.3 ± 0.7-fold greater than rabbit SR vesicles, which express close to equimolar levels of SERCA and SLN. This suggests that horse myofibers exhibit an enhanced SR Ca2+ transport rate and increased luminal Ca2+ stores in vivo. Using the densitometry of Coomassie-stained SDS-PAGE gels, we determined that horse SR vesicles express an abundant level of the luminal SR Ca2+ storage protein calsequestrin (CASQ), with a CASQ-to-SERCA ratio about double that in rabbit SR vesicles. Thus, we propose that SR Ca2+ cycling in horse myofibers is enhanced by a reduced SLN inhibition of SERCA and by an abundant expression of CASQ. Together, these results suggest that horse muscle contractility and susceptibility to exertional rhabdomyolysis are promoted by enhanced SR Ca2+ uptake and luminal Ca2+ storage.
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19
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Nothing Regular about the Regulins: Distinct Functional Properties of SERCA Transmembrane Peptide Regulatory Subunits. Int J Mol Sci 2021; 22:ijms22168891. [PMID: 34445594 PMCID: PMC8396278 DOI: 10.3390/ijms22168891] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 12/11/2022] Open
Abstract
The sarco-endoplasmic reticulum calcium ATPase (SERCA) is responsible for maintaining calcium homeostasis in all eukaryotic cells by actively transporting calcium from the cytosol into the sarco-endoplasmic reticulum (SR/ER) lumen. Calcium is an important signaling ion, and the activity of SERCA is critical for a variety of cellular processes such as muscle contraction, neuronal activity, and energy metabolism. SERCA is regulated by several small transmembrane peptide subunits that are collectively known as the “regulins”. Phospholamban (PLN) and sarcolipin (SLN) are the original and most extensively studied members of the regulin family. PLN and SLN inhibit the calcium transport properties of SERCA and they are required for the proper functioning of cardiac and skeletal muscles, respectively. Myoregulin (MLN), dwarf open reading frame (DWORF), endoregulin (ELN), and another-regulin (ALN) are newly discovered tissue-specific regulators of SERCA. Herein, we compare the functional properties of the regulin family of SERCA transmembrane peptide subunits and consider their regulatory mechanisms in the context of the physiological and pathophysiological roles of these peptides. We present new functional data for human MLN, ELN, and ALN, demonstrating that they are inhibitors of SERCA with distinct functional consequences. Molecular modeling and molecular dynamics simulations of SERCA in complex with the transmembrane domains of MLN and ALN provide insights into how differential binding to the so-called inhibitory groove of SERCA—formed by transmembrane helices M2, M6, and M9—can result in distinct functional outcomes.
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20
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Sarcolipin Exhibits Abundant RNA Transcription and Minimal Protein Expression in Horse Gluteal Muscle. Vet Sci 2020; 7:vetsci7040178. [PMID: 33202832 PMCID: PMC7711957 DOI: 10.3390/vetsci7040178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 11/05/2020] [Indexed: 01/02/2023] Open
Abstract
Ca2+ regulation in equine muscle is important for horse performance, yet little is known about this species-specific regulation. We reported recently that horse encode unique gene and protein sequences for the sarcoplasmic reticulum (SR) Ca2+-transporting ATPase (SERCA) and the regulatory subunit sarcolipin (SLN). Here we quantified gene transcription and protein expression of SERCA and its inhibitory peptides in horse gluteus, as compared to commonly-studied rabbit skeletal muscle. RNA sequencing and protein immunoblotting determined that horse gluteus expresses the ATP2A1 gene (SERCA1) as the predominant SR Ca2+-ATPase isoform and the SLN gene as the most-abundant SERCA inhibitory peptide, as also found in rabbit skeletal muscle. Equine muscle expresses an insignificant level of phospholamban (PLN), another key SERCA inhibitory peptide expressed commonly in a variety of mammalian striated muscles. Surprisingly in horse, the RNA transcript ratio of SLN-to-ATP2A1 is an order of magnitude higher than in rabbit, while the corresponding protein expression ratio is an order of magnitude lower than in rabbit. Thus, SLN is not efficiently translated or maintained as a stable protein in horse muscle, suggesting a non-coding role for supra-abundant SLN mRNA. We propose that the lack of SLN and PLN inhibition of SERCA activity in equine muscle is an evolutionary adaptation that potentiates Ca2+ cycling and muscle contractility in a prey species domestically selected for speed.
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21
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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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22
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Tobias IS, Galpin AJ. Moving human muscle physiology research forward: an evaluation of fiber type-specific protein research methodologies. Am J Physiol Cell Physiol 2020; 319:C858-C876. [DOI: 10.1152/ajpcell.00107.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Human skeletal muscle is a heterogeneous tissue composed of multiple fiber types that express unique contractile and metabolic properties. While analysis of mixed fiber samples predominates and holds value, increasing attention has been directed toward studying proteins segregated by fiber type, a methodological distinction termed “fiber type-specific.” Fiber type-specific protein studies have the advantage of uncovering key molecular effects that are often missed in mixed fiber homogenate studies but also require greater time and resource-intensive methods, particularly when applied to human muscle. This review summarizes and compares current methods used for fiber type-specific protein analysis, highlighting their advantages and disadvantages for human muscle studies, in addition to recent advances in these techniques. These methods can be grouped into three categories based on the initial processing of the tissue: 1) muscle-specific fiber homogenates, 2) cross sections of fiber bundles, and 3) isolated single fibers, with various subtechniques for performing fiber type identification and protein quantification. The relative implementation for each unique methodological approach is analyzed from 83 fiber type-specific studies of proteins in live human muscle found in the literature to date. These studies have investigated several proteins involved in a wide range of cellular functions that are important to muscle tissue. The second half of this review summarizes key findings from this ensemble of fiber type-specific human protein studies. We highlight examples of where this analytical approach has helped to improve understanding of important physiological topics such as insulin sensitivity, muscle hypertrophy, muscle fatigue, and adaptation to different exercise programs.
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Affiliation(s)
- Irene S. Tobias
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Andrew J. Galpin
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
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23
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Braun JL, Geromella MS, Hamstra SI, Fajardo VA. Neuronatin regulates whole-body metabolism: is thermogenesis involved? FASEB Bioadv 2020; 2:579-586. [PMID: 33089074 PMCID: PMC7566048 DOI: 10.1096/fba.2020-00052] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 12/16/2022] Open
Abstract
Neuronatin (NNAT) was originally discovered in 1995 and labeled as a brain developmental gene due to its abundant expression in developing brains. Over the past 25 years, researchers have uncovered NNAT in other tissues; notably, the hypothalamus, pancreatic β‐cells, and adipocytes. Recent evidence in these tissues indicates that NNAT plays a significant role in metabolism whereby it regulates food intake, insulin secretion, and adipocyte differentiation. Furthermore, genetic deletion of Nnat in mice lowers whole‐body energy expenditure and increases susceptibility to diet‐induced obesity and glucose intolerance; however, the underlying cellular mechanisms remain unknown. Based on its sequence homology with phospholamban, NNAT has a purported role in regulating the sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) pump. However, NNAT also shares sequence homology with sarcolipin, which has the unique property of uncoupling the SERCA pump, increasing whole‐body energy expenditure and thus promoting adaptive thermogenesis in states of caloric excess or cold exposure. Thus, in this article, we discuss the accumulating evidence suggestive of NNAT’s role in whole‐body metabolic regulation, while highlighting its potential to mediate adaptive thermogenesis via SERCA uncoupling.
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Affiliation(s)
- Jessica L Braun
- Department of Kinesiology Brock University St. Catharines ON USA.,Centre for Bone and Muscle Health Brock University St. Catharines ON USA.,Centre for Neuroscience Brock University St. Catharines ON USA
| | - Mia S Geromella
- Department of Kinesiology Brock University St. Catharines ON USA.,Centre for Bone and Muscle Health Brock University St. Catharines ON USA
| | - Sophie I Hamstra
- Department of Kinesiology Brock University St. Catharines ON USA.,Centre for Bone and Muscle Health Brock University St. Catharines ON USA
| | - Val A Fajardo
- Department of Kinesiology Brock University St. Catharines ON USA.,Centre for Bone and Muscle Health Brock University St. Catharines ON USA.,Centre for Neuroscience Brock University St. Catharines ON USA
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24
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Sun X, Wang W, Dong Y, Wang Y, Zhang M, Wang Z, Yu X, Huang J, Cai H. Relationship between calcium circulation-related factors and muscle strength in rat sciatic nerve injury model. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2020; 23:654-662. [PMID: 32742604 PMCID: PMC7375001 DOI: 10.22038/ijbms.2020.40915.9695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The purpose of this study is to investigate the indication function of the calcium circulation-related factors on the damage to muscle strength and contraction function after nerve injury. The target factors include ryanodine receptor (RyR), inositol-1,4,5-triphosphate receptor (IP3R), phospholamban (PLN), cryptocalcitonin (CASQ), ATPase and troponin C (TNNC). MATERIALS AND METHODS Sprague-Dawley (SD) rats were randomly divided into sham-operated group (SO), sciatic nerve injury group (SNI) and sciatic nerve disconnection group (SNT). Sciatic nerve function index and stretching test were used to examine the changes to muscle strength; bilateral gastrocnemius muscles were extracted after execution for gastrocnemius wet weight ratio test. HE staining slides and average cross-sectional area of muscle fibers were acquired to analyze the muscle atrophy. The transcription level of the factors was also measured. RESULTS Sciatic nerve damage in SNI group was significantly higher than that in SO group in the 6 weeks, but there was no significant difference between SNT and SO groups fallowing sciatic nerve damage. Sciatic nerve function in SNT group was worse than that in SNI group. The average cross-sectional area of gastrocnemius muscle fibers in SNI and SNT groups was significantly reduced compared to that in SO group. The transcriptional levels of RyR, PLN, CASQ, ATPase and TNNC in SNI and SNT groups were significantly different from those in SO group. CONCLUSION Calcium circulation-related factors could be used as potential indicators for assessment of damages to muscle strength.
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Affiliation(s)
- Xiaoming Sun
- Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China
| | - Wei Wang
- Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China
| | - Yangyi Dong
- Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China
| | - Yue Wang
- Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China
| | - Meixiang Zhang
- Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China
| | - Zhao Wang
- Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China
| | - Xiaowei Yu
- Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China
| | - Jiao Huang
- Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China
| | - Hongxing Cai
- Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China,Corresponding author: Hongxing Cai. Department of Forensic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, P. R. China. Tel: 0516-85748442
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25
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Gorrell E, Shemery A, Kowalski J, Bodziony M, Mavundza N, Titus AR, Yoder M, Mull S, Heemstra LA, Wagner JG, Gibson M, Carey O, Daniel D, Harvey N, Zendlo M, Rich M, Everett S, Gavini CK, Almundarij TI, Lorton D, Novak CM. Skeletal muscle thermogenesis induction by exposure to predator odor. J Exp Biol 2020; 223:jeb218479. [PMID: 32165434 PMCID: PMC7174837 DOI: 10.1242/jeb.218479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 03/02/2020] [Indexed: 01/07/2023]
Abstract
Non-shivering thermogenesis can promote negative energy balance and weight loss. In this study, we identified a contextual stimulus that induces rapid and robust thermogenesis in skeletal muscle. Rats exposed to the odor of a natural predator (ferret) showed elevated skeletal muscle temperatures detectable as quickly as 2 min after exposure, reaching maximum thermogenesis of >1.5°C at 10-15 min. Mice exhibited a similar thermogenic response to the same odor. Ferret odor induced a significantly larger and qualitatively different response from that of novel or aversive odors, fox odor or moderate restraint stress. Exposure to predator odor increased energy expenditure, and both the thermogenic and energetic effects persisted when physical activity levels were controlled. Predator odor-induced muscle thermogenesis is subject to associative learning as exposure to a conditioned stimulus provoked a rise in muscle temperature in the absence of the odor. The ability of predator odor to induce thermogenesis is predominantly controlled by sympathetic nervous system activation of β-adrenergic receptors, as unilateral sympathetic lumbar denervation and a peripherally acting β-adrenergic antagonist significantly inhibited predator odor-induced muscle thermogenesis. The potential survival value of predator odor-induced changes in muscle physiology is reflected in an enhanced resistance to running fatigue. Lastly, predator odor-induced muscle thermogenesis imparts a meaningful impact on energy expenditure as daily predator odor exposure significantly enhanced weight loss with mild calorie restriction. This evidence signifies contextually provoked, centrally mediated muscle thermogenesis that meaningfully impacts energy balance.
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Affiliation(s)
- Erin Gorrell
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Ashley Shemery
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Jesse Kowalski
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Miranda Bodziony
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Nhlalala Mavundza
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Amber R Titus
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Mark Yoder
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Sarah Mull
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Lydia A Heemstra
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Jacob G Wagner
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Megan Gibson
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Olivia Carey
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Diamond Daniel
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Nicholas Harvey
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Meredith Zendlo
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Megan Rich
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Scott Everett
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Chaitanya K Gavini
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
| | - Tariq I Almundarij
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
- Department of Veterinary Medicine, College of Agriculture and Veterinary Medicine, Qassim University, PO Box 6622, Buraidah 51452, Saudi Arabia
| | - Diane Lorton
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Colleen M Novak
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
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26
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Peixoto JVC, Santos ASR, Corso CR, da Silva FS, Capote A, Ribeiro CD, Abreu BJDGA, Acco A, Fogaça RH, Dias FAL. Thirty-day experimental diabetes impairs contractility and increases fatigue resistance in rat diaphragm muscle associated with increased anti-oxidative activity. Can J Physiol Pharmacol 2020; 98:490-497. [PMID: 32243773 DOI: 10.1139/cjpp-2019-0609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Diabetes mellitus is a metabolic disorder that can generate tissue damage through several pathways. Alteration and dysfunction of skeletal muscle are reported including respiratory muscles, which may compromise respiratory parameters in diabetic patients. We have aimed to evaluate the diaphragm muscle contractility, tissue remodeling, oxidative stress, and inflammatory parameters from 30 day streptozotocin-treated rats. The diaphragm contractility was assessed using isolated muscle, tissue remodeling using histology and zymography techniques, and tissue oxidative stress and inflammatory parameters by enzyme activity assay. Our data revealed in the diabetes mellitus group an increase in maximum tetanic force (4.82 ± 0.13 versus 4.24 ± 0.18 N/cm2 (p = 0.015)) and fatigue resistance (139.16 ± 10.78 versus 62.25 ± 4.45 s (p < 0.001)), reduction of 35.4% in muscle trophism (p < 0.001), increase of 32.6% of collagen deposition (p = 0.007), reduction of 21.3% in N-acetylglucosaminidase activity (p < 0.001), and increase of 246.7% of catalase activity (p = 0.002) without changes in reactive oxygen species (p = 0.518) and tissue lipid peroxidation (p = 0.664). All observed changes are attributed to the poor glycemic control (471.20 ± 16.91 versus 80.00 ± 3.42 mg/dL (p < 0.001)), which caused defective tissue regeneration and increased catalase activity as a compensatory mechanism.
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Affiliation(s)
- João Victor Capelli Peixoto
- Department of Physiology, Federal University of Paraná, Av. Francisco H. dos Santos 100, Jardim das Américas, Curitiba, Paraná 81531-980, Brazil
| | - Antônio Sérgio Rocha Santos
- Department of Physiology, Federal University of Paraná, Av. Francisco H. dos Santos 100, Jardim das Américas, Curitiba, Paraná 81531-980, Brazil
| | - Claudia Rita Corso
- Department of Pharmacology, Federal University of Paraná, Av. Francisco H. dos Santos 100, Jardim das Américas, Curitiba, Paraná 81531-980, Brazil
| | - Flavio Santos da Silva
- Department of Health Sciences, Federal Rural University of the Semi-Arid, Av. Francisco Mota 572, Pres. Costa e Silva, Mossoró, Rio Grande do Norte 59625-900, Brazil
| | - Andrielle Capote
- Department of Physiology, Federal University of Paraná, Av. Francisco H. dos Santos 100, Jardim das Américas, Curitiba, Paraná 81531-980, Brazil
| | - Cibele Dias Ribeiro
- Department of Physiology, Federal University of Paraná, Av. Francisco H. dos Santos 100, Jardim das Américas, Curitiba, Paraná 81531-980, Brazil
| | - Bento João da Graça Azevedo Abreu
- Department of Morphology, Federal University of Rio Grande do Norte, Av. Senador Salgado Filho 3000, Candelária, Natal, Rio Grande do Norte 59064-741, Brazil
| | - Alexandra Acco
- Department of Pharmacology, Federal University of Paraná, Av. Francisco H. dos Santos 100, Jardim das Américas, Curitiba, Paraná 81531-980, Brazil
| | - Rosalvo Hochmueller Fogaça
- Department of Physiology, Federal University of Paraná, Av. Francisco H. dos Santos 100, Jardim das Américas, Curitiba, Paraná 81531-980, Brazil
| | - Fernando Augusto Lavezzo Dias
- Department of Physiology, Federal University of Paraná, Av. Francisco H. dos Santos 100, Jardim das Américas, Curitiba, Paraná 81531-980, Brazil
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27
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Rodríguez Y, Májeková M. Structural Changes of Sarco/Endoplasmic Reticulum Ca 2+-ATPase Induced by Rutin Arachidonate: A Molecular Dynamics Study. Biomolecules 2020; 10:biom10020214. [PMID: 32024167 PMCID: PMC7072167 DOI: 10.3390/biom10020214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 01/15/2020] [Accepted: 01/28/2020] [Indexed: 11/16/2022] Open
Abstract
Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) maintains the level of calcium concentration in cells by pumping calcium ions from the cytoplasm to the lumen while undergoing substantial conformational changes, which can be stabilized or prevented by various compounds. Here we attempted to clarify the molecular mechanism of action of new inhibitor rutin arachidonate, one of the series of the acylated rutin derivatives. We performed molecular dynamics simulations of SERCA1a protein bound to rutin arachidonate positioned in a pure dipalmitoylphosphatidylcholine bilayer membrane. Our study predicted the molecular basis for the binding of rutin arachidonate towards SERCA1a in the vicinity of the binding site of calcium ions and near the location of the well-known inhibitor thapsigargin. The stable hydrogen bond between Glu771 and rutin arachidonate plays a key role in the binding. SERCA1a is kept in the E2 conformation preventing the formation of important salt bridges between the side chains of several residues, primarily Glu90 and Lys297. All in all, the structural changes induced by the binding of rutin arachidonate to SERCA1a may shift proton balance near the titrable residues Glu771 and Glu309 into neutral species, hence preventing the binding of calcium ions to the transmembrane binding sites and thus affecting calcium homeostasis. Our results could lead towards the design of new types of inhibitors, potential drug candidates for cancer treatment, which could be anchored to the transmembrane region of SERCA1a by a lipophilic fatty acid group.
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Affiliation(s)
- Yoel Rodríguez
- Department of Natural Sciences, Eugenio María de Hostos Community College of The City University of New York, 500 Grand Concourse, Bronx, New York, NY 10451, USA; or
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, New York, NY 10029, USA
| | - Magdaléna Májeková
- Center of Experimental Medicine of Slovak Academy of Sciences, Institute of Experimental Pharmacology and Toxicology, Department of Biochemical Pharmacology, Dubravska cesta 9, 841 04 Bratislava, Slovakia
- Correspondence: ; Tel.: +421-2-3229-5709
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28
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Morales‐Alamo D, Martinez‐Canton M, Gelabert‐Rebato M, Martin‐Rincon M, Pablos‐Velasco P, Holmberg H, Calbet JAL. Sarcolipin expression in human skeletal muscle: Influence of energy balance and exercise. Scand J Med Sci Sports 2019; 30:408-420. [DOI: 10.1111/sms.13594] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 10/08/2019] [Accepted: 10/29/2019] [Indexed: 12/18/2022]
Affiliation(s)
- David Morales‐Alamo
- Department of Physical Education University of Las Palmas de Gran Canaria Campus Universitario de Tafira s/n Las Palmas de Gran Canaria Spain
- IUIBS Instituto de Investigaciones Biomédicas y Sanitarias de Las Palmas de Gran Canaria Canary Islands Spain
| | - Miriam Martinez‐Canton
- IUIBS Instituto de Investigaciones Biomédicas y Sanitarias de Las Palmas de Gran Canaria Canary Islands Spain
| | - Miriam Gelabert‐Rebato
- Department of Physical Education University of Las Palmas de Gran Canaria Campus Universitario de Tafira s/n Las Palmas de Gran Canaria Spain
- IUIBS Instituto de Investigaciones Biomédicas y Sanitarias de Las Palmas de Gran Canaria Canary Islands Spain
- Nektium Pharma Las Palmas de Gran Canaria Spain
| | - Marcos Martin‐Rincon
- Department of Physical Education University of Las Palmas de Gran Canaria Campus Universitario de Tafira s/n Las Palmas de Gran Canaria Spain
- IUIBS Instituto de Investigaciones Biomédicas y Sanitarias de Las Palmas de Gran Canaria Canary Islands Spain
| | - Pedro Pablos‐Velasco
- IUIBS Instituto de Investigaciones Biomédicas y Sanitarias de Las Palmas de Gran Canaria Canary Islands Spain
- Service of Endocrinology and Nutrition Hospital Universitario de Gran Canaria Doctor Negrín Las Palmas de Gran Canaria Spain
| | - Hans‐Christer Holmberg
- Department of Health Sciences Swedish Winter Sports Research Centre Mid Sweden University Östersund Sweden
| | - Jose A. L. Calbet
- Department of Physical Education University of Las Palmas de Gran Canaria Campus Universitario de Tafira s/n Las Palmas de Gran Canaria Spain
- IUIBS Instituto de Investigaciones Biomédicas y Sanitarias de Las Palmas de Gran Canaria Canary Islands Spain
- Department of Physical Performance Norwegian School of Sport Sciences Oslo Norway
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29
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Kurgan N, Whitley KC, Maddalena LA, Moradi F, Stoikos J, Hamstra SI, Rubie EA, Kumar M, Roy BD, Woodgett JR, Stuart JA, Fajardo VA. A Low-Therapeutic Dose of Lithium Inhibits GSK3 and Enhances Myoblast Fusion in C2C12 Cells. Cells 2019; 8:cells8111340. [PMID: 31671858 PMCID: PMC6912290 DOI: 10.3390/cells8111340] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 10/23/2019] [Accepted: 10/26/2019] [Indexed: 12/14/2022] Open
Abstract
Glycogen synthase kinase 3 (GSK3) slows myogenic differentiation and myoblast fusion partly by inhibiting the Wnt/β-catenin signaling pathway. Lithium, a common medication for bipolar disorder, inhibits GSK3 via Mg+ competition and increased Ser21 (GSK3α) or Ser9 (GSK3β) phosphorylation, leading to enhanced myoblast fusion and myogenic differentiation. However, previous studies demonstrating the effect of lithium on GSK3 have used concentrations up to 10 mM, which greatly exceeds concentrations measured in the serum of patients being treated for bipolar disorder (0.5–1.2 mM). Here, we determined whether a low-therapeutic (0.5 mM) dose of lithium could promote myoblast fusion and myogenic differentiation in C2C12 cells. C2C12 myotubes differentiated for three days in media containing 0.5 mM lithium chloride (LiCl) had significantly higher GSK3β (ser9) and GSK3α (ser21) phosphorylation compared with control myotubes differentiated in the same media without LiCl (+2–2.5 fold, p < 0.05), a result associated with an increase in total β-catenin. To further demonstrate that 0.5 mM LiCl inhibited GSK3 activity, we also developed a novel GSK3-specific activity assay. Using this enzyme-linked spectrophotometric assay, we showed that 0.5 mM LiCl-treated myotubes had significantly reduced GSK3 activity (−86%, p < 0.001). Correspondingly, 0.5 mM LiCl treated myotubes had a higher myoblast fusion index compared with control (p < 0.001) and significantly higher levels of markers of myogenesis (myogenin, +3-fold, p < 0.001) and myogenic differentiation (myosin heavy chain, +10-fold, p < 0.001). These results indicate that a low-therapeutic dose of LiCl is sufficient to promote myoblast fusion and myogenic differentiation in muscle cells, which has implications for the treatment of several myopathic conditions.
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Affiliation(s)
- Nigel Kurgan
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Kennedy C. Whitley
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Lucas A. Maddalena
- Department of Biological Sciences, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (L.A.M.); (F.M.); (J.A.S.)
| | - Fereshteh Moradi
- Department of Biological Sciences, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (L.A.M.); (F.M.); (J.A.S.)
| | - Joshua Stoikos
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
| | - Sophie I. Hamstra
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Elizabeth A. Rubie
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON M5G 1X5, Canada; (E.A.R.); (M.K.); (J.R.W.)
| | - Megha Kumar
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON M5G 1X5, Canada; (E.A.R.); (M.K.); (J.R.W.)
| | - Brian D. Roy
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - James R. Woodgett
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON M5G 1X5, Canada; (E.A.R.); (M.K.); (J.R.W.)
| | - Jeffrey A. Stuart
- Department of Biological Sciences, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (L.A.M.); (F.M.); (J.A.S.)
| | - Val A. Fajardo
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
- Correspondence:
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30
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Gamu D, Juracic ES, Hall KJ, Tupling AR. The sarcoplasmic reticulum and SERCA: a nexus for muscular adaptive thermogenesis. Appl Physiol Nutr Metab 2019; 45:1-10. [PMID: 31116956 DOI: 10.1139/apnm-2019-0067] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We are currently facing an "obesity epidemic" worldwide. Promoting inefficient metabolism in muscle represents a potential treatment for obesity and its complications. Sarco(endo)plasmic reticulum (SR) Ca2+-ATPase (SERCA) pumps in muscle are responsible for maintaining low cytosolic Ca2+ concentration through the ATP-dependent pumping of Ca2+ from the cytosol into the SR lumen. SERCA activity has the potential to be a critical regulator of body mass and adiposity given that it is estimated to contribute upwards of 20% of daily energy expenditure. More interestingly, this fraction can be modified physiologically in the face of stressors, such as ambient temperature and diet, through its physical interaction with several regulators known to inhibit Ca2+ uptake and muscle function. In this review, we discuss advances in our understanding of Ca2+-cycling thermogenesis within skeletal muscle, focusing on SERCA and its protein regulators, which were thought previously to only modulate muscular contractility. Novelty ATP consumption by SERCA pumps comprises a large proportion of resting energy expenditure in muscle and is dynamically regulated through interactions with small SERCA regulatory proteins. SERCA efficiency correlates significantly with resting metabolism, such that individuals with a higher resting metabolic rate have less energetically efficient SERCA Ca2+ pumping in muscle (i.e., lower coupling ratio). Futile Ca2+ cycling is a versatile heat generating mechanism utilized by both skeletal muscle and beige fat.
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Affiliation(s)
- Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Emma Sara Juracic
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Karlee J Hall
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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31
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Fajardo VA, Chambers PJ, Juracic ES, Rietze BA, Gamu D, Bellissimo C, Kwon F, Quadrilatero J, Russell Tupling A. Sarcolipin deletion in mdx mice impairs calcineurin signalling and worsens dystrophic pathology. Hum Mol Genet 2019; 27:4094-4102. [PMID: 30137316 DOI: 10.1093/hmg/ddy302] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 08/15/2018] [Indexed: 12/11/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most severe form of muscular dystrophy affecting 1 in 3500 live male births. Although there is no cure for DMD, therapeutic strategies aimed at enhancing calcineurin signalling and promoting the slow fibre phenotype have shown promise in mdx mice, which is the classical mouse model for DMD. Sarcolipin (SLN) is a small protein that regulates the sarco(endo)plasmic reticulum Ca2+-ATPase pump and its expression is highly upregulated in dystrophic skeletal muscle. We have recently shown that SLN in skeletal muscle amplifies calcineurin signalling thereby increasing myofibre size and the slow fibre phenotype. Therefore, in the present study we sought to determine the physiological impact of genetic Sln deletion in mdx mice, particularly on calcineurin signalling, fibre-type distribution and size and dystrophic pathology. We generated an mdx/Sln-null (mdx/SlnKO) mouse colony and hypothesized that the soleus and diaphragm muscles from these mice would display blunted calcineurin signalling, smaller myofibre sizes, an increased proportion of fast fibres and worsened dystrophic pathology compared with mdx mice. Our results show that calcineurin signalling was impaired in mdx/SlnKO mice as indicated by reductions in utrophin, stabilin-2 and calcineurin expression. In addition, mdx/SlnKO muscles contained smaller myofibres, exhibited a slow-to-fast fibre-type switch that corresponded with reduced expression of mitochondrial proteins and displayed a worsened dystrophic pathology compared with mdx muscles. Altogether, our findings demonstrate a critical role for SLN upregulation in dystrophic muscles and suggest that SLN can be viewed as a potential therapeutic target.
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Affiliation(s)
- Val A Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Paige J Chambers
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Emma S Juracic
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Bradley A Rietze
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | | | - Frenk Kwon
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
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32
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Elrabie Ahmed M, Bando H, Fuse S, Mostafa Abdelfattah H, Elrabie Ahmed M, Abdel-Kader Ahmed M, Tsujikawa T, Hisa Y. Differential isoform expression of SERCA and myosin heavy chain in hypopharyngeal muscles. ACTA ACUST UNITED AC 2019; 39:220-229. [PMID: 30933182 PMCID: PMC6734200 DOI: 10.14639/0392-100x-2185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/12/2018] [Indexed: 11/25/2022]
Abstract
Composition of slow, fast and hybrid fibres of pharyngeal muscles,
associated with pharyngeal movements and regulation, has been rarely
studied. The present study aimed to identify expression of
sarcoplasmic reticulum Ca2+ ATPase (SERCA) and myosin heavy
chain (MHC) and hybrid isoforms in different pharyngeal muscles of
young and aged rats as well as humans. Isoform expression profiles of
SERCA, MHC and hybrid isoforms among six components of pharyngeal
muscle were immunohistochemically evaluated in rat and human. The
result showed that pharyngeal muscles predominantly expressed fast
fibres (SERCA1 and MHCII), whereas expression of slow fibres (SERCA2
and MHCI) was low, but different depending on muscle components. Inner
layer of pharyngeal muscles expressed more SERCA2 and hybrid fibres
than the outer layer. Pharyngeal muscles in aged rats showed increased
hybrid fibers and SERCA2. Human thyropharyngeus also showed a higher
portion of fast fibres compared to cricopharyngeus. Thus, in contrast
to abundance of fast fibres, slow and hybrid fibres are differentially
expressed depending on muscle components and layers as well as aging.
These results lead to further understanding of coordinated regulation
for speech and swallowing. The unique data presented in this study on
SERCA isoform expressions in both rats and human suggest an ability to
handle calcium changes according functional demands.
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Affiliation(s)
- Mohammed Elrabie Ahmed
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Otorhinolaryngology-Head and Neck Surgery, Sohag University Hospitals, Faculty of Medicine, Sohag University, Sohag, Egypt
| | - H Bando
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - S Fuse
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - H Mostafa Abdelfattah
- Department of Otorhinolaryngology-Head and Neck Surgery, Alexandria University, Alexandria, Egypt
| | - Mona Elrabie Ahmed
- Unit of Phoniatrics-Department of Otorhinolaryngology-Head and Neck Surgery, Sohag University, Egypt
| | - M Abdel-Kader Ahmed
- Department of Otorhinolaryngology-Head and Neck Surgery, Sohag University Hospitals, Faculty of Medicine, Sohag University, Sohag, Egypt
| | - T Tsujikawa
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Y Hisa
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Speech and Hearing Sciences and Disorders, Kyoto Gakuen University, Japan
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33
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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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Komatsu M, Nakada T, Kawagishi H, Kato H, Yamada M. Increase in phospholamban content in mouse skeletal muscle after denervation. J Muscle Res Cell Motil 2019; 39:163-173. [DOI: 10.1007/s10974-019-09504-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/20/2019] [Indexed: 10/27/2022]
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Glaves JP, Primeau JO, Espinoza-Fonseca LM, Lemieux MJ, Young HS. The Phospholamban Pentamer Alters Function of the Sarcoplasmic Reticulum Calcium Pump SERCA. Biophys J 2019; 116:633-647. [PMID: 30712785 DOI: 10.1016/j.bpj.2019.01.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 11/30/2018] [Accepted: 01/11/2019] [Indexed: 11/17/2022] Open
Abstract
The interaction of phospholamban (PLN) with the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) pump is a major regulatory axis in cardiac muscle contractility. The prevailing model involves reversible inhibition of SERCA by monomeric PLN and storage of PLN as an inactive pentamer. However, this paradigm has been challenged by studies demonstrating that PLN remains associated with SERCA and that the PLN pentamer is required for the regulation of cardiac contractility. We have previously used two-dimensional (2D) crystallization and electron microscopy to study the interaction between SERCA and PLN. To further understand this interaction, we compared small helical crystals and large 2D crystals of SERCA in the absence and presence of PLN. In both crystal forms, SERCA molecules are organized into identical antiparallel dimer ribbons. The dimer ribbons pack together with distinct crystal contacts in the helical versus large 2D crystals, which allow PLN differential access to potential sites of interaction with SERCA. Nonetheless, we show that a PLN oligomer interacts with SERCA in a similar manner in both crystal forms. In the 2D crystals, a PLN pentamer interacts with transmembrane segments M3 of SERCA and participates in a crystal contact that bridges neighboring SERCA dimer ribbons. In the helical crystals, an oligomeric form of PLN also interacts with M3 of SERCA, though the PLN oligomer straddles a SERCA-SERCA crystal contact. We conclude that the pentameric form of PLN interacts with M3 of SERCA and that it plays a distinct structural and functional role in SERCA regulation. The interaction of the pentamer places the cytoplasmic domains of PLN at the membrane surface proximal to the calcium entry funnel of SERCA. This interaction may cause localized perturbation of the membrane bilayer as a mechanism for increasing the turnover rate of SERCA.
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Affiliation(s)
- John Paul Glaves
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Joseph O Primeau
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - L Michel Espinoza-Fonseca
- Center for Arrhythmia Research, Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Howard S Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada.
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Sahu B, Pani S, Swalsingh G, Bal NC. Non and Epigenetic Mechanisms in Regulation of Adaptive Thermogenesis in Skeletal Muscle. Front Endocrinol (Lausanne) 2019; 10:517. [PMID: 31456746 PMCID: PMC6700214 DOI: 10.3389/fendo.2019.00517] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 07/15/2019] [Indexed: 01/07/2023] Open
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Tobias IS, Lazauskas KK, Arevalo JA, Bagley JR, Brown LE, Galpin AJ. Fiber type-specific analysis of AMPK isoforms in human skeletal muscle: advancement in methods via capillary nanoimmunoassay. J Appl Physiol (1985) 2018; 124:840-849. [DOI: 10.1152/japplphysiol.00894.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human skeletal muscle is a heterogeneous mixture of multiple fiber types (FT). Unfortunately, present methods for FT-specific study are constrained by limits of protein detection in single-fiber samples. These limitations beget compensatory resource-intensive procedures, ultimately dissuading investigators from pursuing FT-specific research. Additionally, previous studies neglected hybrid FT, confining their analyses to only pure FT. Here we present novel methods of protein detection across a wider spectrum of human skeletal muscle FT using fully automated capillary nanoimmunoassay (CNIA) technology. CNIA allowed a ~20-fold-lower limit of 5′-AMP-activated protein kinase (AMPK) detection compared with Western blotting. We then performed FT-specific assessment of AMPK expression as a proof of concept. Individual human muscle fibers were mechanically isolated, dissolved, and myosin heavy chain (MHC) fiber typed via SDS-PAGE. Single-fiber samples were combined in pairs and grouped into MHC I, MHC I/IIa, MHC IIa, and MHC IIa/IIx for expression analysis of AMPK isoforms α1, α2, β1, β2, γ2, and γ3 with a tubulin loading control. Significant FT-specific differences were found for α2 (1.7-fold higher in MHC IIa and MHC IIa/IIx vs. others), γ2 (2.5-fold higher in MHC IIa vs. others), and γ3 (2-fold higher in MHC IIa and 4-fold higher in MHC IIa/IIx vs. others). Development of a protocol that combines the efficient and sensitive CNIA technology with comprehensive SDS-PAGE fiber typing marks an important advancement in FT-specific research because it allows more precise study of the molecular mechanisms governing metabolism, adaptation, and regulation in human muscle. NEW & NOTEWORTHY We demonstrate the viability of applying capillary nanoimmunoassay technology to the study of fiber type-specific protein analysis in human muscle fibers. This novel technique enables a ~20-fold-lower limit of protein detection compared with traditional Western blotting methods. Combined with SDS-PAGE methods of fiber typing, we apply this technique to compare 5′-AMP-activated protein kinase isoform expression in myosin heavy chain (MHC) I, MHC I/IIa, MHC IIa, and MHC IIa/IIx fiber types.
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Affiliation(s)
- Irene S. Tobias
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Kara K. Lazauskas
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Jose A. Arevalo
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - James R. Bagley
- Muscle Physiology Laboratory, Department of Kinesiology, San Francisco State University, San Francisco, California
| | - Lee E. Brown
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Andrew J. Galpin
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
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Blondin DP, Haman F. Shivering and nonshivering thermogenesis in skeletal muscles. HANDBOOK OF CLINICAL NEUROLOGY 2018; 156:153-173. [PMID: 30454588 DOI: 10.1016/b978-0-444-63912-7.00010-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Humans have inherited complex neural circuits which drive behavioral, somatic, and autonomic thermoregulatory responses to defend their body temperature. While they are well adapted to dissipate heat in warm climates, they have a reduced capacity to preserve it in cold environments. Consequently, heat production is critical to defending their core temperature. As in other large mammals, skeletal muscles are the primary source of heat production recruited in cold-exposed humans. This is achieved voluntarily in the form of contractions from exercising muscles or involuntarily in the form of contractions from shivering muscles and the recruitment of nonshivering mechanisms. This review describes our current understanding of shivering and nonshivering thermogenesis in skeletal muscles, from the neural circuitry driving their recruitment to the metabolic substrates that fuel them. The presence of these heat-producing mechanisms can be measured in vivo by combining indirect respiratory calorimetry with electromyography or biomedical imaging modalities. Indeed, much of what is known regarding shivering in humans and other animal models stems from studies performed using these methods combined with in situ and in vivo neurologic techniques. More recent investigations have focused on understanding the metabolic processes that produce the heat from both contracting and noncontracting mechanisms. With the growing interest in the potential therapeutic benefits of shivering and nonshivering skeletal muscle to counter the effects of neuromuscular, cardiovascular, and metabolic diseases, we expect this field to continue its growth in the coming years.
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Affiliation(s)
- Denis P Blondin
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada.
| | - François Haman
- Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
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Cold acclimation causes fiber type-specific responses in glucose and fat metabolism in rat skeletal muscles. Sci Rep 2017; 7:15430. [PMID: 29133865 PMCID: PMC5684227 DOI: 10.1038/s41598-017-15842-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/02/2017] [Indexed: 01/03/2023] Open
Abstract
This study investigated fiber type-specific metabolic responses and the molecular mechanisms that regulate glucose and fat metabolism in oxidative and glycolytic muscles upon cold acclimation. Male Wistar rats were exposed to cold (4 °C) for 7 days, and then glycogen synthesis and content, glucose and palmitate oxidation, and the molecular mechanisms underlying these metabolic pathways were assessed in soleus (Sol), extensor digitorum longus (EDL), and epitrochlearis (Epit) muscles. Cold acclimation increased glycogen synthesis, glycogen content, glucose oxidation, and reduced glycogen synthase (GS) phosphorylation only in Sol muscles. Protein kinase B (AKT), glycogen synthase kinase 3 (GSK3), and AMP-activated protein kinase (AMPK) phosphorylation increased in all three muscles upon cold acclimation. Cold acclimation increased palmitate oxidation, gene expression of the transcriptional co-activator Pgc-1α, lipoprotein lipase (Lpl), fatty acid transporter (Cd36), and Sarco/endoplasmic reticulum Ca2+-ATPase (Serca) in Sol, EDL, and Epit muscles. Sarcolipin was only detected and had its content increased in Sol muscles. In conclusion, cold-induced thermogenesis activated similar signaling pathways in oxidative and glycolytic muscles, but the metabolic fate of glucose differed in skeletal muscles with distinct fiber type composition. Furthermore, only muscles rich in type I fibers appeared to have the capacity for sarcolipin-mediated SERCA uncoupling.
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40
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Ravel-Chapuis A, Bélanger G, Côté J, Michel RN, Jasmin BJ. Misregulation of calcium-handling proteins promotes hyperactivation of calcineurin-NFAT signaling in skeletal muscle of DM1 mice. Hum Mol Genet 2017; 26:2192-2206. [PMID: 28369518 DOI: 10.1093/hmg/ddx109] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 03/16/2017] [Indexed: 12/26/2022] Open
Abstract
Myotonic Dystrophy type 1 (DM1) is caused by an expansion of CUG repeats in DMPK mRNAs. This mutation affects alternative splicing through misregulation of RNA-binding proteins. Amongst pre-mRNAs that are mis-spliced, several code for proteins involved in calcium homeostasis suggesting that calcium-handling and signaling are perturbed in DM1. Here, we analyzed expression of such proteins in DM1 mouse muscle. We found that the levels of several sarcoplasmic reticulum proteins (SERCA1, sarcolipin and calsequestrin) are altered, likely contributing to an imbalance in calcium homeostasis. We also observed that calcineurin (CnA) signaling is hyperactivated in DM1 muscle. Indeed, CnA expression and phosphatase activity are both markedly increased in DM1 muscle. Coherent with this, we found that activators of the CnA pathway (MLP, FHL1) are also elevated. Consequently, NFATc1 expression is increased in DM1 muscle and becomes relocalized to myonuclei, together with an up-regulation of its transcriptional targets (RCAN1.4 and myoglobin). Accordingly, DM1 mouse muscles display an increase in oxidative metabolism and fiber hypertrophy. To determine the functional consequences of this CnA hyperactivation, we administered cyclosporine A, an inhibitor of CnA, to DM1 mice. Muscles of treated DM1 mice showed an increase in CUGBP1 levels, and an exacerbation of key alternative splicing events associated with DM1. Finally, inhibition of CnA in cultured human DM1 myoblasts also resulted in a splicing exacerbation of the insulin receptor. Together, these findings show for the first time that calcium-CnA signaling is hyperactivated in DM1 muscle and that such hyperactivation represents a beneficial compensatory adaptation to the disease.
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Affiliation(s)
- Aymeric Ravel-Chapuis
- Department of Cellular and Molecular Medicine and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Guy Bélanger
- Department of Cellular and Molecular Medicine and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Robin N Michel
- Department of Exercise Science, Faculty of Arts and Science, Concordia University, Montreal, QC, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
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Desmond PF, Labuza A, Muriel J, Markwardt ML, Mancini AE, Rizzo MA, Bloch RJ. Interactions between small ankyrin 1 and sarcolipin coordinately regulate activity of the sarco(endo)plasmic reticulum Ca 2+-ATPase (SERCA1). J Biol Chem 2017; 292:10961-10972. [PMID: 28487373 PMCID: PMC5491780 DOI: 10.1074/jbc.m117.783613] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/08/2017] [Indexed: 11/06/2022] Open
Abstract
SERCA1, the sarco(endo)plasmic reticulum Ca2+-ATPase of skeletal muscle, is essential for muscle relaxation and maintenance of low resting Ca2+ levels in the myoplasm. We recently reported that small ankyrin 1 (sAnk1) interacts with the sarco(endo)plasmic reticulum Ca2+-ATPase in skeletal muscle (SERCA1) to inhibit its activity. We also showed that this interaction is mediated at least in part through sAnk1's transmembrane domain in a manner similar to that of sarcolipin (SLN). Earlier studies have shown that SLN and phospholamban, the other well studied small SERCA-regulatory proteins, oligomerize either alone or together. As sAnk1 is coexpressed with SLN in muscle, we sought to determine whether these two proteins interact with one another when coexpressed exogenously in COS7 cells. Coimmunoprecipitation (coIP) and anisotropy-based FRET (AFRET) assays confirmed this interaction. Our results indicated that sAnk1 and SLN can associate in the sarcoplasmic reticulum membrane and after exogenous expression in COS7 cells in vitro but that their association did not require endogenous SERCA2. Significantly, SLN promoted the interaction between sAnk1 and SERCA1 when the three proteins were coexpressed, and both coIP and AFRET experiments suggested the formation of a complex consisting of all three proteins. Ca2+-ATPase assays showed that sAnk1 ablated SLN's inhibition of SERCA1 activity. These results suggest that sAnk1 interacts with SLN both directly and in complex with SERCA1 and reduces SLN's inhibitory effect on SERCA1 activity.
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Affiliation(s)
- Patrick F Desmond
- From the Department of Physiology and
- Programs in Biochemistry and Molecular Biology
| | - Amanda Labuza
- From the Department of Physiology and
- Neuroscience, and
| | | | | | - Allison E Mancini
- Molecular Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Megan A Rizzo
- From the Department of Physiology and
- Neuroscience, and
- Molecular Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Robert J Bloch
- From the Department of Physiology and
- Programs in Biochemistry and Molecular Biology
- Neuroscience, and
- Molecular Medicine, University of Maryland, Baltimore, Maryland 21201
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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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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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Fajardo VA, Trojanowski N, Castelli LM, Miotto PM, Amoye F, Ward WE, Tupling AR, LeBlanc PJ. Saturation of SERCA's lipid annulus may protect against its thermal inactivation. Biochem Biophys Res Commun 2017; 484:456-460. [PMID: 28137585 DOI: 10.1016/j.bbrc.2017.01.154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 01/26/2017] [Indexed: 12/25/2022]
Abstract
The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pumps are integral membrane proteins that catalyze the active transport of Ca2+ into the sarcoplasmic reticulum, thereby eliciting muscle relaxation. SERCA pumps are highly susceptible to oxidative damage, and cytoprotection of SERCA dampens thermal inactivation and is a viable therapeutic strategy in combating diseases where SERCA activity is impaired, such as muscular dystrophy. Here, we sought to determine whether increasing the percent of saturated fatty acids (SFA) within SERCA's lipid annulus through diet could protect SERCA pumps from thermal inactivation. Female Wistar rats were fed either a semi-purified control diet (AIN93G, 7% soybean oil by weight) or a modified AIN93G diet containing high SFA (20% lard by weight) for 17 weeks. Soleus muscles were extracted and SERCA lipid annulus and activity under thermal stress were analyzed. Our results show that SERCA's lipid annulus is abundant with short-chain (12-14 carbon) fatty acids, which corresponds well with SERCA's predicted bilayer thickness of 21 Å. Under control-fed conditions, SERCA's lipid annulus was already highly saturated (79%), and high-fat feeding did not increase this any further. High-fat feeding did not mitigate the reductions in SERCA activity seen with thermal stress; however, correlational analyses revealed significant and strong associations between % SFA and thermal stability of SERCA activity with greater %SFA being associated with lower thermal inactivation and greater % polyunsaturation and unsaturation index being associated with increased thermal inactivation. Altogether, these findings show that SERCA's lipid annulus may influence its susceptibility to oxidative damage, which could have implications in muscular dystrophy and age-related muscle wasting.
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Affiliation(s)
- Val Andrew Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada; Center for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada; Department of Health Sciences, Brock University, St. Catharines, ON, Canada
| | - Natalie Trojanowski
- Center for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada; Department of Health Sciences, Brock University, St. Catharines, ON, Canada
| | - Laura M Castelli
- Center for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada; Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - Paula M Miotto
- Center for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada; Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - Foyinsola Amoye
- Center for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada; Department of Health Sciences, Brock University, St. Catharines, ON, Canada
| | - Wendy E Ward
- Center for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada; Department of Health Sciences, Brock University, St. Catharines, ON, Canada; Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada; Center for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada
| | - Paul J LeBlanc
- Center for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada; Department of Health Sciences, Brock University, St. Catharines, ON, Canada.
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45
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de Anda-Jáuregui G, Velázquez-Caldelas TE, Espinal-Enríquez J, Hernández-Lemus E. Transcriptional Network Architecture of Breast Cancer Molecular Subtypes. Front Physiol 2016; 7:568. [PMID: 27920729 PMCID: PMC5118907 DOI: 10.3389/fphys.2016.00568] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 11/08/2016] [Indexed: 12/22/2022] Open
Abstract
Breast cancer heterogeneity is evident at the clinical, histological and molecular level. High throughput technologies allowed the identification of intrinsic subtypes that capture transcriptional differences among tumors. A remaining question is whether said differences are associated to a particular transcriptional program which involves different connections between the same molecules. In other words, whether particular transcriptional network architectures can be linked to specific phenotypes. In this work we infer, construct and analyze transcriptional networks from whole-genome gene expression microarrays, by using an information theory approach. We use 493 samples of primary breast cancer tissue classified in four molecular subtypes: Luminal A, Luminal B, Basal and HER2-enriched. For comparison, a network for non-tumoral mammary tissue (61 samples) is also inferred and analyzed. Transcriptional networks present particular architectures in each breast cancer subtype as well as in the non-tumor breast tissue. We find substantial differences between the non-tumor network and those networks inferred from cancer samples, in both structure and gene composition. More importantly, we find specific network architectural features associated to each breast cancer subtype. Based on breast cancer networks' centrality, we identify genes previously associated to the disease, either, generally (i.e., CNR2) or to a particular subtype (such as LCK). Similarly, we identify LUZP4, a gene barely explored in breast cancer, playing a role in transcriptional networks with subtype-specific relevance. With this approach we observe architectural differences between cancer and non-cancer at network level, as well as differences between cancer subtype networks which might be associated with breast cancer heterogeneity. The centrality measures of these networks allow us to identify genes with potential biomedical implications to breast cancer.
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Affiliation(s)
| | | | - Jesús Espinal-Enríquez
- Computational Genomics, National Institute of Genomic MedicineMexico City, Mexico
- Complejidad en Biología de Sistemas, Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de MéxicoMexico City, Mexico
| | - Enrique Hernández-Lemus
- Computational Genomics, National Institute of Genomic MedicineMexico City, Mexico
- Complejidad en Biología de Sistemas, Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de MéxicoMexico City, Mexico
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Fajardo VA, Smith IC, Bombardier E, Chambers PJ, Quadrilatero J, Tupling AR. Diaphragm assessment in mice overexpressing phospholamban in slow-twitch type I muscle fibers. Brain Behav 2016; 6:e00470. [PMID: 27134770 PMCID: PMC4842933 DOI: 10.1002/brb3.470] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 03/08/2016] [Accepted: 03/11/2016] [Indexed: 12/30/2022] Open
Abstract
AIMS Phospholamban (PLN) and sarcolipin (SLN) are small inhibitory proteins that regulate the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) pump. Previous work from our laboratory revealed that in the soleus and gluteus minimus muscles of mice overexpressing PLN (Pln (OE)), SERCA function was impaired, dynamin 2 (3-5 fold) and SLN (7-9 fold) were upregulated, and features of human centronuclear myopathy (CNM) were observed. Here, we performed structural and functional experiments to evaluate whether the diaphragm muscles of the Pln (OE) mouse would exhibit CNM pathology and muscle weakness. METHODS Diaphragm muscles from Pln (OE) and WT mice were subjected to histological/histochemical/immunofluorescent staining, Ca(2+)-ATPase and Ca(2+) uptake assays, Western blotting, and in vitro electrical stimulation. RESULTS Our results demonstrate that PLN overexpression reduced SERCA's apparent affinity for Ca(2+) but did not reduce maximal SERCA activity or rates of Ca(2+) uptake. SLN was upregulated 2.5-fold, whereas no changes in dynamin 2 expression were found. With respect to CNM, we did not observe type I fiber predominance, central nuclei, or central aggregation of oxidative activity in diaphragm, although type I fiber hypotrophy was present. Furthermore, in vitro contractility assessment of Pln (OE) diaphragm strips revealed no reductions in force-generating capacity, maximal rates of relaxation or force development, but did indicate that ½ relaxation time was prolonged. CONCLUSIONS Therefore, the effects of PLN overexpression on skeletal muscle phenotype differ between diaphragm and the postural soleus and gluteus minimus muscles. Our findings here point to differences in SLN expression and type I fiber distribution as potential contributing factors.
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Affiliation(s)
| | - Ian Curtis Smith
- Department of Kinesiology University of Waterloo Waterloo ON Canada
| | - Eric Bombardier
- Department of Kinesiology University of Waterloo Waterloo ON Canada
| | - Paige J Chambers
- Department of Kinesiology University of Waterloo Waterloo ON Canada
| | - Joe Quadrilatero
- Department of Kinesiology University of Waterloo Waterloo ON Canada
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Hide and Seek: Protein-coding Sequences Inside "Non-coding" RNAs. GENOMICS PROTEOMICS & BIOINFORMATICS 2016; 14:179-80. [PMID: 27071812 PMCID: PMC4996849 DOI: 10.1016/j.gpb.2016.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 03/31/2016] [Indexed: 11/23/2022]
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Abstract
Limb-girdle muscular dystrophy type 2A (LGMD2A) is a form of muscular dystrophy caused by
mutations in calpain 3 (CAPN3). Several studies have implicated Ca2+
dysregulation as an underlying event in several muscular dystrophies, including LGMD2A. In
this study we used mouse and human myotube cultures, and muscle biopsies in order to
determine whether dysfunction of sarco/endoplasmatic Ca2+-ATPase (SERCA) is
involved in the pathology of this disease. In CAPN3-deficient myotubes, we found decreased
levels of SERCA 1 and 2 proteins, while mRNA levels remained comparable with control
myotubes. Also, we found a significant reduction in SERCA function that resulted in
impairment of Ca2+ homeostasis, and elevated basal intracellular
[Ca2+] in human myotubes. Furthermore, small Ankyrin 1 (sAnk1), a
SERCA1-binding protein that is involved in sarcoplasmic reticulum integrity, was also
diminished in CAPN3-deficient fibres. Interestingly, SERCA2 protein was patently reduced
in muscles from LGMD2A patients, while it was normally expressed in other forms of
muscular dystrophy. Thus, analysis of SERCA2 expression may prove useful for diagnostic
purposes as a potential indicator of CAPN3 deficiency in muscle biopsies. Altogether, our
results indicate that CAPN3 deficiency leads to degradation of SERCA proteins and
Ca2+ dysregulation in the skeletal muscle. While further studies are needed
in order to elucidate the specific contribution of SERCA towards muscle degeneration in
LGMD2A, this study constitutes a reasonable foundation for the development of therapeutic
approaches targeting SERCA1, SERCA2 or sAnk1.
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Whitfield J, Ludzki A, Heigenhauser GJF, Senden JMG, Verdijk LB, van Loon LJC, Spriet LL, Holloway GP. Beetroot juice supplementation reduces whole body oxygen consumption but does not improve indices of mitochondrial efficiency in human skeletal muscle. J Physiol 2015; 594:421-35. [PMID: 26457670 DOI: 10.1113/jp270844] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 09/29/2015] [Indexed: 12/23/2022] Open
Abstract
KEY POINTS Oral consumption of nitrate (NO3(-)) in beetroot juice has been shown to decrease the oxygen cost of submaximal exercise; however, the mechanism of action remains unresolved. We supplemented recreationally active males with beetroot juice to determine if this altered mitochondrial bioenergetics. Despite reduced submaximal exercise oxygen consumption, measures of mitochondrial coupling and respiratory efficiency were not altered in muscle. In contrast, rates of mitochondrial hydrogen peroxide (H2O2) emission were increased in the absence of markers of lipid or protein oxidative damage. These results suggest that improvements in mitochondrial oxidative metabolism are not the cause of beetroot juice-mediated improvements in whole body oxygen consumption. ABSTRACT Ingestion of sodium nitrate (NO3(-)) simultaneously reduces whole body oxygen consumption (V̇O2) during submaximal exercise while improving mitochondrial efficiency, suggesting a causal link. Consumption of beetroot juice (BRJ) elicits similar decreases in V̇O2 but potential effects on the mitochondria remain unknown. Therefore we examined the effects of 7-day supplementation with BRJ (280 ml day(-1), ∼26 mmol NO3(-)) in young active males (n = 10) who had muscle biopsies taken before and after supplementation for assessments of mitochondrial bioenergetics. Subjects performed 20 min of cycling (10 min at 50% and 70% V̇O2 peak) 48 h before 'Pre' (baseline) and 'Post' (day 5 of supplementation) biopsies. Whole body V̇O2 decreased (P < 0.05) by ∼3% at 70% V̇O2 peak following supplementation. Mitochondrial respiration in permeabilized muscle fibres showed no change in leak respiration, the content of proteins associated with uncoupling (UCP3, ANT1, ANT2), maximal substrate-supported respiration, or ADP sensitivity (apparent Km). In addition, isolated subsarcolemmal and intermyofibrillar mitochondria showed unaltered assessments of mitochondrial efficiency, including ADP consumed/oxygen consumed (P/O ratio), respiratory control ratios and membrane potential determined fluorometrically using Safranine-O. In contrast, rates of mitochondrial hydrogen peroxide (H2O2) emission were increased following BRJ. Therefore, in contrast to sodium nitrate, BRJ supplementation does not alter key parameters of mitochondrial efficiency. This occurred despite a decrease in exercise V̇O2, suggesting that the ergogenic effects of BRJ ingestion are not due to a change in mitochondrial coupling or efficiency. It remains to be determined if increased mitochondrial H2O2 contributes to this response.
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Affiliation(s)
- J Whitfield
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - A Ludzki
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - G J F Heigenhauser
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada, L8N 3Z5
| | - J M G Senden
- Department of Human Movement Sciences, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, 6200 MD, Maastricht, The Netherlands
| | - L B Verdijk
- Department of Human Movement Sciences, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, 6200 MD, Maastricht, The Netherlands
| | - L J C van Loon
- Department of Human Movement Sciences, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, 6200 MD, Maastricht, The Netherlands
| | - L L Spriet
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - G P Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
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Gamu D, Trinh A, Bombardier E, Tupling AR. Persistence of diet-induced obesity despite access to voluntary activity in mice lacking sarcolipin. Physiol Rep 2015; 3:3/9/e12549. [PMID: 26400985 PMCID: PMC4600390 DOI: 10.14814/phy2.12549] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Several rodent models of obesity have been shown to develop excessive adiposity only when voluntary cage ambulation is restricted. We have previously shown that mice lacking the sarco(endo)plasmic reticulum Ca2+-ATPase pump regulatory protein sarcolipin (Sln–/–), an uncoupler of Ca2+ uptake, develop excessive diet-induced obesity under standard housing conditions. However, it is unclear whether this phenotype is due, in part, to the sedentary housing environment in which these animals are kept. To address this, we allowed wild-type and Sln–/– animals ad libitum access to voluntary wheel running while consuming a standard chow or high-fat diet for 8 weeks. During this period, wheel revolutions were monitored along with weekly mass gain. Postdiet glucose tolerance and visceral adiposity were also taken. The volume of wheel running completed was similar between genotype, regardless of diet. Although voluntary activity reduced mass gain relative to sedentary controls within each diet (P < 0.05), visceral adiposity was surprisingly unaltered with activity. However, Sln–/– mice developed excessive obesity (P < 0.05) and glucose intolerance (P < 0.05) with high-fat feeding relative to wild-type controls. These findings indicate that the excessive diet-induced obese phenotype previously observed in Sln–/– mice is not the result of severely restricted daily ambulation, but in fact the inability to recruit uncoupling of the Ca2+-ATPase pump.
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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
| | - 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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