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Liang W, Xu F, Li L, Peng C, Sun H, Qiu J, Sun J. Epigenetic control of skeletal muscle atrophy. Cell Mol Biol Lett 2024; 29:99. [PMID: 38978023 PMCID: PMC11229277 DOI: 10.1186/s11658-024-00618-1] [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: 03/25/2024] [Accepted: 06/26/2024] [Indexed: 07/10/2024] Open
Abstract
Skeletal muscular atrophy is a complex disease involving a large number of gene expression regulatory networks and various biological processes. Despite extensive research on this topic, its underlying mechanisms remain elusive, and effective therapeutic approaches are yet to be established. Recent studies have shown that epigenetics play an important role in regulating skeletal muscle atrophy, influencing the expression of numerous genes associated with this condition through the addition or removal of certain chemical modifications at the molecular level. This review article comprehensively summarizes the different types of modifications to DNA, histones, RNA, and their known regulators. We also discuss how epigenetic modifications change during the process of skeletal muscle atrophy, the molecular mechanisms by which epigenetic regulatory proteins control skeletal muscle atrophy, and assess their translational potential. The role of epigenetics on muscle stem cells is also highlighted. In addition, we propose that alternative splicing interacts with epigenetic mechanisms to regulate skeletal muscle mass, offering a novel perspective that enhances our understanding of epigenetic inheritance's role and the regulatory network governing skeletal muscle atrophy. Collectively, advancements in the understanding of epigenetic mechanisms provide invaluable insights into the study of skeletal muscle atrophy. Moreover, this knowledge paves the way for identifying new avenues for the development of more effective therapeutic strategies and pharmaceutical interventions.
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Affiliation(s)
- Wenpeng Liang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, 26001, China
- Department of Prenatal Screening and Diagnosis Center, Affiliated Maternity and Child Health Care Hospital of Nantong University, Nantong, 226001, China
| | - Feng Xu
- Department of Endocrinology, Affiliated Hospital 2 of Nantong University and First People's Hospital of Nantong City, Nantong, 226001, China
| | - Li Li
- Nantong Center for Disease Control and Prevention, Medical School of Nantong University, Nantong, 226001, China
| | - Chunlei Peng
- Department of Medical Oncology, Tumor Hospital Affiliated to Nantong University, Nantong, 226000, China
| | - Hualin Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, 26001, China
| | - Jiaying Qiu
- Department of Prenatal Screening and Diagnosis Center, Affiliated Maternity and Child Health Care Hospital of Nantong University, Nantong, 226001, China.
| | - Junjie Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, 26001, China.
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2
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Xu J, Li C, Kang X. The epigenetic regulatory effect of histone acetylation and deacetylation on skeletal muscle metabolism-a review. Front Physiol 2023; 14:1267456. [PMID: 38148899 PMCID: PMC10749939 DOI: 10.3389/fphys.2023.1267456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/24/2023] [Indexed: 12/28/2023] Open
Abstract
Skeletal muscles, the largest organ responsible for energy metabolism in most mammals, play a vital role in maintaining the body's homeostasis. Epigenetic modification, specifically histone acetylation, serves as a crucial regulatory mechanism influencing the physiological processes and metabolic patterns within skeletal muscle metabolism. The intricate process of histone acetylation modification involves coordinated control of histone acetyltransferase and deacetylase levels, dynamically modulating histone acetylation levels, and precisely regulating the expression of genes associated with skeletal muscle metabolism. Consequently, this comprehensive review aims to elucidate the epigenetic regulatory impact of histone acetylation modification on skeletal muscle metabolism, providing invaluable insights into the intricate molecular mechanisms governing epigenetic modifications in skeletal muscle metabolism.
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Affiliation(s)
| | | | - Xiaolong Kang
- College of Animal Science and Technology, Ningxia University, Yinchuan, China
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3
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Dent JR, Stocks B, Campelj DG, Philp A. Transient changes to metabolic homeostasis initiate mitochondrial adaptation to endurance exercise. Semin Cell Dev Biol 2023; 143:3-16. [PMID: 35351374 DOI: 10.1016/j.semcdb.2022.03.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 01/26/2022] [Accepted: 03/19/2022] [Indexed: 12/14/2022]
Abstract
Endurance exercise is well established to increase mitochondrial content and function in skeletal muscle, a process termed mitochondrial biogenesis. Current understanding is that exercise initiates skeletal muscle mitochondrial remodeling via modulation of cellular nutrient, energetic and contractile stress pathways. These subtle changes in the cellular milieu are sensed by numerous transduction pathways that serve to initiate and coordinate an increase in mitochondrial gene transcription and translation. The result of these acute signaling events is the promotion of growth and assembly of mitochondria, coupled to a greater capacity for aerobic ATP provision in skeletal muscle. The aim of this review is to highlight the acute metabolic events induced by endurance exercise and the subsequent molecular pathways that sense this transient change in cellular homeostasis to drive mitochondrial adaptation and remodeling.
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Affiliation(s)
- Jessica R Dent
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Ben Stocks
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Dean G Campelj
- Mitochondrial Metabolism and Ageing Laboratory, Healthy Ageing Research Theme, Garvan Institute of Medical Research, Sydney, Australia
| | - Andrew Philp
- Mitochondrial Metabolism and Ageing Laboratory, Healthy Ageing Research Theme, Garvan Institute of Medical Research, Sydney, Australia; St Vincent's Medical School, UNSW Sydney, Sydney, Australia.
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4
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Hernández-Ramírez S, Salcedo-Tello P, Osorio-Gómez D, Bermúdez-Rattoni F, Pacheco-López G, Ferreira G, Lafenetre P, Guzmán-Ramos KR. Voluntary physical activity improves spatial and recognition memory deficits induced by post-weaning chronic exposure to a high-fat diet. Physiol Behav 2022; 254:113910. [PMID: 35820628 DOI: 10.1016/j.physbeh.2022.113910] [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] [Received: 02/08/2022] [Revised: 07/02/2022] [Accepted: 07/08/2022] [Indexed: 11/19/2022]
Abstract
Childhood and adolescent exposure to obesogenic environments has contributed to the development of several health disorders, including neurocognitive impairment. Adolescence is a critical neurodevelopmental window highly influenced by environmental factors that affect brain function until adulthood. Post-weaning chronic exposure to a high-fat diet (HFD) adversely affects memory performance; physical activity is one approach to coping with these dysfunctions. Previous studies indicate that voluntary exercise prevents HFD's detrimental effects on memory; however, it remains to evaluate whether it has a remedial/therapeutical effect when introduced after a long-term HFD exposure. This study was conducted on a diet-induced obesity mice model over six months. After three months of HFD exposure (without interrupting the diet) access to voluntary physical activity was provided. HFD produced weight gain, increased adiposity, and impaired glucose tolerance. Voluntary physical exercise ameliorated glucose tolerance and halted weight gain and fat accumulation. Additionally, physical activity mitigated HFD-induced spatial and recognition memory impairments. Our data indicate that voluntary physical exercise starting after several months of periadolescent HFD exposure reverses metabolic and cognitive alterations demonstrating that voluntary exercise, in addition to its known preventive effect, also has a restorative impact on metabolism and cognition dysfunctions associated with obesity.
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Affiliation(s)
- Susana Hernández-Ramírez
- Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana (UAM), Av. de las Garzas No. 10, Lerma de Villada, Estado de México, C.P. 52005, Mexico
| | - Pamela Salcedo-Tello
- Departamento de Ciencias de la Salud, División de Ciencias Biológicas y de la Salud. Universidad Autónoma Metropolitana (UAM), Unidad Lerma. Av. de las Garzas No. 10, Col. el Panteón, Lerma de Villada, Estado de México, C.P. 52005, Mexico
| | - Daniel Osorio-Gómez
- División de Neurociencias. Instituto de Fisiología Celular. Universidad Nacional Autónoma de México (UNAM). Circuito Exterior, Ciudad Universitaria, 04510 Mexico City
| | - Federico Bermúdez-Rattoni
- División de Neurociencias. Instituto de Fisiología Celular. Universidad Nacional Autónoma de México (UNAM). Circuito Exterior, Ciudad Universitaria, 04510 Mexico City
| | - Gustavo Pacheco-López
- Departamento de Ciencias de la Salud, División de Ciencias Biológicas y de la Salud. Universidad Autónoma Metropolitana (UAM), Unidad Lerma. Av. de las Garzas No. 10, Col. el Panteón, Lerma de Villada, Estado de México, C.P. 52005, Mexico
| | - Guillaume Ferreira
- Université de Bordeaux, INRAE, Bordeaux INP, NutriNeuro Laboratory, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Pauline Lafenetre
- Université de Bordeaux, Nutrition and Integrative Neurobiology, UMR 1286, Bordeaux, France
| | - Kioko R Guzmán-Ramos
- Departamento de Ciencias de la Salud, División de Ciencias Biológicas y de la Salud. Universidad Autónoma Metropolitana (UAM), Unidad Lerma. Av. de las Garzas No. 10, Col. el Panteón, Lerma de Villada, Estado de México, C.P. 52005, Mexico.
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5
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Stocks B, Zierath JR. Post-translational Modifications: The Signals at the Intersection of Exercise, Glucose Uptake, and Insulin Sensitivity. Endocr Rev 2022; 43:654-677. [PMID: 34730177 PMCID: PMC9277643 DOI: 10.1210/endrev/bnab038] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Indexed: 11/19/2022]
Abstract
Diabetes is a global epidemic, of which type 2 diabetes makes up the majority of cases. Nonetheless, for some individuals, type 2 diabetes is eminently preventable and treatable via lifestyle interventions. Glucose uptake into skeletal muscle increases during and in recovery from exercise, with exercise effective at controlling glucose homeostasis in individuals with type 2 diabetes. Furthermore, acute and chronic exercise sensitizes skeletal muscle to insulin. A complex network of signals converge and interact to regulate glucose metabolism and insulin sensitivity in response to exercise. Numerous forms of post-translational modifications (eg, phosphorylation, ubiquitination, acetylation, ribosylation, and more) are regulated by exercise. Here we review the current state of the art of the role of post-translational modifications in transducing exercise-induced signals to modulate glucose uptake and insulin sensitivity within skeletal muscle. Furthermore, we consider emerging evidence for noncanonical signaling in the control of glucose homeostasis and the potential for regulation by exercise. While exercise is clearly an effective intervention to reduce glycemia and improve insulin sensitivity, the insulin- and exercise-sensitive signaling networks orchestrating this biology are not fully clarified. Elucidation of the complex proteome-wide interactions between post-translational modifications and the associated functional implications will identify mechanisms by which exercise regulates glucose homeostasis and insulin sensitivity. In doing so, this knowledge should illuminate novel therapeutic targets to enhance insulin sensitivity for the clinical management of type 2 diabetes.
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Affiliation(s)
- Ben Stocks
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Juleen R Zierath
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.,Departments of Molecular Medicine and Surgery and Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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6
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Dayanidhi S, Buckner EH, Redmond RS, Chambers HG, Schenk S, Lieber RL. Skeletal muscle maximal mitochondrial activity in ambulatory children with cerebral palsy. Dev Med Child Neurol 2021; 63:1194-1203. [PMID: 33393083 DOI: 10.1111/dmcn.14785] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/19/2020] [Indexed: 12/16/2022]
Abstract
AIM To compare skeletal muscle mitochondrial enzyme activity and mitochondrial content between independently ambulatory children with cerebral palsy (CP) and typically developing children. METHOD Gracilis biopsies were obtained from 12 children during surgery (n=6/group, children with CP: one female, five males, mean age 13y 4mo, SD 5y 1mo, 4y 1mo-17y 10mo; typically developing children: three females, three males, mean age 16y 5mo, SD 1y 4mo, 14y 6mo-18y 2mo). Spectrophotometric enzymatic assays were used to evaluate the activity of mitochondrial electron transport chain complexes. Mitochondrial content was evaluated using citrate synthase assay, mitochondrial DNA copy number, and immunoblots for specific respiratory chain proteins. RESULTS Maximal enzyme activity was significantly (50-80%) lower in children with CP versus typically developing children, for complex I (11nmol/min/mg protein, standard error of the mean [SEM] 1.7 vs 20.7nmol/min/mg protein, SEM 4), complex II (6.9nmol/min/mg protein, SEM 1.2 vs 21nmol/min/mg protein, SEM 2.7), complex III (31.9nmol/min/mg protein, SEM 7.4 vs 72.7nmol/min/mg protein, SEM 7.2), and complex I+III (7.4nmol/min/mg protein, SEM 2.5 vs 31.8nmol/min/mg protein, SEM 9.3). Decreased electron transport chain activity was not the result of lower mitochondrial content. INTERPRETATION Skeletal muscle mitochondrial electron transport chain enzymatic activity but not mitochondrial content is reduced in independently ambulatory children with CP. Decreased mitochondrial oxidative capacity might explain reported increased energetics of movement and fatigue in ambulatory children with CP. What this paper adds Skeletal muscle mitochondrial electron transport chain enzymatic activity is reduced in independently ambulatory children with cerebral palsy (CP). Mitochondrial content appears to be similar between children with CP and typically developing children.
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Affiliation(s)
- Sudarshan Dayanidhi
- Department of Orthopaedic Surgery, University of California, San Diego, CA, USA.,Department of Veterans Affairs Medical Center, San Diego, CA, USA.,Shirley Ryan AbilityLab, Chicago, IL, USA
| | - Elisa H Buckner
- Department of Orthopaedic Surgery, University of California, San Diego, CA, USA.,Biomedical Sciences Program, University of California, San Diego, CA, USA
| | | | - Henry G Chambers
- Department of Orthopaedic Surgery, University of California, San Diego, CA, USA.,Department of Orthopaedics, Rady Children's Hospital, San Diego, CA, USA
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California, San Diego, CA, USA.,Biomedical Sciences Program, University of California, San Diego, CA, USA
| | - Richard L Lieber
- Department of Orthopaedic Surgery, University of California, San Diego, CA, USA.,Department of Veterans Affairs Medical Center, San Diego, CA, USA.,Shirley Ryan AbilityLab, Chicago, IL, USA.,Department of Bioengineering, University of California, San Diego, CA, USA
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7
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McGee SL, Hargreaves M. Exercise adaptations: molecular mechanisms and potential targets for therapeutic benefit. Nat Rev Endocrinol 2020; 16:495-505. [PMID: 32632275 DOI: 10.1038/s41574-020-0377-1] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/29/2020] [Indexed: 12/19/2022]
Abstract
Exercise is fundamental for good health, whereas physical inactivity underpins many chronic diseases of modern society. It is well appreciated that regular exercise improves metabolism and the metabolic phenotype in a number of tissues. The phenotypic alterations observed in skeletal muscle are partly mediated by transcriptional responses that occur following each individual bout of exercise. This adaptive response increases oxidative capacity and influences the function of myokines and extracellular vesicles that signal to other tissues. Our understanding of the epigenetic and transcriptional mechanisms that mediate the skeletal muscle gene expression response to exercise as well as of their upstream signalling pathways has advanced substantially in the past 10 years. With this knowledge also comes the opportunity to design new therapeutic strategies based on the biology of exercise for a variety of chronic conditions where regular exercise might be a challenge. This Review provides an overview of the beneficial adaptive responses to exercise and details the molecular mechanisms involved. The possibility of designing therapeutic interventions based on these molecular mechanisms is addressed, using relevant examples that have exploited this approach.
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Affiliation(s)
- Sean L McGee
- Metabolic Research Unit, School of Medicine and Institute for Mental and Physical Health and Clinical Translation (iMPACT), Deakin University, Geelong, Victoria, Australia.
| | - Mark Hargreaves
- Department of Physiology, The University of Melbourne, Parkville, Victoria, Australia.
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8
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Allerton TD, Kowalski G, Hang H, Stephens J. Dynamic Glucose Disposal is Driven by Reduced Endogenous Glucose Production in Response to Voluntary Wheel Running: A Stable Isotope Approach. Am J Physiol Endocrinol Metab 2020; 319:E2-E10. [PMID: 32343613 PMCID: PMC7468781 DOI: 10.1152/ajpendo.00450.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 12/12/2022]
Abstract
To resolve both the systems level and molecular mechanisms responsible for exercise induced improvements in glucose tolerance, we sought to test the effect of voluntary wheel running exercise on postprandial glucose dynamics. We utilized a stable isotope labeled oral glucose tolerance test (SI-OGTT) incorporating complimentary deuterium glucose tracers at 1:1 ratio (2-2H-glucose and 6-6 2H-glucose; 2g/kg lean body mass) to distinguish between endogenous glucose production (EGP) and whole-body glucose disposal. SI-OGTT was performed in C57BL/6J mice after 8 weeks on a high fat diet (45% fat). Mice were then randomized to either a wheel running cage (n=13, HFD Ex) or normal cage (n=13, HFD Sed) while maintaining the HFD for 4 weeks prior to performing a SI-OGTT. HFD Ex mice demonstrated improvements in whole blood glucose total AUC that was attributed primarily to a reduction in EGP AUC. Serum insulin levels measured at 0 and 15-minutes post glucose gavage were significantly elevated in the HFD Sed mice, whereas HFD Ex mice demonstrated the expected reduction in insulin at both time points. Overall, exercise improved hepatic insulin sensitivity by reducing postprandial EGP, but also increased whole-body glucose disposal. Finally, these results demonstrate the benefits of exercise on hepatic insulin sensitivity by combining a more physiological route of glucose administration (oral glucose) with the resolution of stable isotope tracers. These novel observations clearly demonstrate that SI-OGTT is a sensitive and cost-effective method to measure exercise adaptations in obese mice with as little as 2 µl of tail blood.
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Affiliation(s)
| | - Greg Kowalski
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Hardy Hang
- Pennington Biomedical Research Center, Baton Rouge LA, United States
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9
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Svensson K, LaBarge SA, Sathe A, Martins VF, Tahvilian S, Cunliffe JM, Sasik R, Mahata SK, Meyer GA, Philp A, David LL, Ward SR, McCurdy CE, Aslan JE, Schenk S. p300 and cAMP response element-binding protein-binding protein in skeletal muscle homeostasis, contractile function, and survival. J Cachexia Sarcopenia Muscle 2020; 11:464-477. [PMID: 31898871 PMCID: PMC7113519 DOI: 10.1002/jcsm.12522] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/22/2019] [Accepted: 11/14/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Reversible ε-amino acetylation of lysine residues regulates transcription as well as metabolic flux; however, roles for specific lysine acetyltransferases in skeletal muscle physiology and function are unknown. In this study, we investigated the role of the related acetyltransferases p300 and cAMP response element-binding protein-binding protein (CBP) in skeletal muscle transcriptional homeostasis and physiology in adult mice. METHODS Mice with skeletal muscle-specific and inducible knockout of p300 and CBP (PCKO) were generated by crossing mice with a tamoxifen-inducible Cre recombinase expressed under the human α-skeletal actin promoter with mice having LoxP sites flanking exon 9 of the Ep300 and Crebbp genes. Knockout of PCKO was induced at 13-15 weeks of age via oral gavage of tamoxifen for 5 days to both PCKO and littermate control [wildtype (WT)] mice. Body composition, food intake, and muscle function were assessed on day 0 (D0) through 5 (D5). Microarray and tandem mass tag mass spectrometry analyses were performed to assess global RNA and protein levels in skeletal muscle of PCKO and WT mice. RESULTS At D5 after initiating tamoxifen treatment, there was a reduction in body weight (-15%), food intake (-78%), stride length (-46%), and grip strength (-45%) in PCKO compared with WT mice. Additionally, ex vivo contractile function [tetanic tension (kPa)] was severely impaired in PCKO vs. WT mice at D3 (~70-80% lower) and D5 (~80-95% lower) and resulted in lethality within 1 week-a phenotype that is reversed by the presence of a single allele of either p300 or CBP. The impaired muscle function in PCKO mice was paralleled by substantial transcriptional alterations (3310 genes; false discovery rate < 0.1), especially in gene networks central to muscle contraction and structural integrity. This transcriptional uncoupling was accompanied by changes in protein expression patterns indicative of impaired muscle function, albeit to a smaller magnitude (446 proteins; fold-change > 1.25; false discovery rate < 0.1). CONCLUSIONS These data reveal that p300 and CBP are required for the control and maintenance of contractile function and transcriptional homeostasis in skeletal muscle and, ultimately, organism survival. By extension, modulating p300/CBP function may hold promise for the treatment of disorders characterized by impaired contractile function in humans.
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Affiliation(s)
- Kristoffer Svensson
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA, USA
| | - Samuel A LaBarge
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA, USA
| | - Abha Sathe
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA, USA
| | - Vitor F Martins
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA, USA.,Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Shahriar Tahvilian
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA, USA
| | - Jennifer M Cunliffe
- Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Roman Sasik
- Center for Computational Biology and Bioinformatics, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Sushil K Mahata
- VA San Diego Healthcare System, San Diego, CA, USA.,Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Gretchen A Meyer
- Program in Physical Therapy and Departments of Neurology, Biomedical Engineering and Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Andrew Philp
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - Larry L David
- Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Samuel R Ward
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA, USA.,Department of Radiology, University of California San Diego, La Jolla, CA, USA.,Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Carrie E McCurdy
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | - Joseph E Aslan
- Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health and Science University, Portland, OR, USA.,Knight Cardiovascular Institute, School of Medicine, Oregon Health and Science University, Portland, OR, USA.,Department of Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA, USA.,Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA, USA
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10
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Svensson K, Tahvilian S, Martins VF, Dent JR, Lemanek A, Barooni N, Greyslak K, McCurdy CE, Schenk S. Combined overexpression of SIRT1 and knockout of GCN5 in adult skeletal muscle does not affect glucose homeostasis or exercise performance in mice. Am J Physiol Endocrinol Metab 2020; 318:E145-E151. [PMID: 31794263 PMCID: PMC7052578 DOI: 10.1152/ajpendo.00370.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sirtuin 1 (SIRT1) and general control of amino acid synthesis 5 (GCN5) regulate mitochondrial biogenesis via opposing modulation of peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) acetylation status and activity. However, the combined contribution of SIRT1 and GCN5 to skeletal muscle metabolism and endurance performance in vivo is unknown. In this study, we investigated the impact of combined skeletal muscle-specific overexpression of SIRT1 and deletion of GCN5 on glucose homeostasis, skeletal muscle mitochondrial biogenesis and function, and metabolic adaptation to endurance exercise training in mice. We generated mice with combined and tamoxifen-inducible skeletal muscle-specific overexpression of SIRT1 and knockout of GCN5 (dTG) and floxed [wild type (WT)] littermates using a Cre-LoxP approach. All mice were treated with tamoxifen at 5-6 wk of age, and 4-7 wk later glucose homeostasis, skeletal muscle contractile function, mitochondrial function, and the effects of 14 days of voluntary wheel running on expression of metabolic proteins and exercise capacity were assessed. There was no difference in oral glucose tolerance, skeletal muscle contractile function, mitochondrial abundance, or maximal respiratory capacity between dTG and WT mice. Additionally, there were no genotype differences in exercise performance and markers of mitochondrial biogenesis after 14 days of voluntary wheel running. These results demonstrate that combined overexpression of SIRT1 and loss of GCN5 in vivo does not promote metabolic remodeling in skeletal muscle of sedentary or exercise-trained mice.
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Affiliation(s)
- Kristoffer Svensson
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Shahriar Tahvilian
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Vitor F Martins
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California
| | - Jessica R Dent
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Adrianna Lemanek
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Neeka Barooni
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Keenan Greyslak
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Carrie E McCurdy
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California
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11
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Dent JR, Hetrick B, Tahvilian S, Sathe A, Greyslak K, LaBarge SA, Svensson K, McCurdy CE, Schenk S. Skeletal muscle mitochondrial function and exercise capacity are not impaired in mice with knockout of STAT3. J Appl Physiol (1985) 2019; 127:1117-1127. [PMID: 31513449 DOI: 10.1152/japplphysiol.00003.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Signal transducer and activator of transcription 3 (STAT3) was recently found to be localized to mitochondria in a number of tissues and cell types, where it modulates oxidative phosphorylation via interactions with the electron transport proteins, complex I and complex II. Skeletal muscle is densely populated with mitochondria although whether STAT3 contributes to skeletal muscle oxidative capacity is unknown. In the present study, we sought to elucidate the contribution of STAT3 to mitochondrial and skeletal muscle function by studying mice with muscle-specific knockout of STAT3 (mKO). First, we developed a novel flow cytometry-based approach to confirm that STAT3 is present in skeletal muscle mitochondria. However, contrary to findings in other tissue types, complex I and complex II activity and maximal mitochondrial respiratory capacity in skeletal muscle were comparable between mKO mice and floxed/wild-type littermates. Moreover, there were no genotype differences in endurance exercise performance, skeletal muscle force-generating capacity, or the adaptive response of skeletal muscle to voluntary wheel running. Collectively, although we confirm the presence of STAT3 in skeletal muscle mitochondria, our data establish that STAT3 is dispensable for mitochondrial and physiological function in skeletal muscle.NEW & NOTEWORTHY Whether signal transducer and activator of transcription 3 (STAT3) can regulate the activity of complex I and II of the electron transport chain and mitochondrial oxidative capacity in skeletal muscle, as it can in other tissues, is unknown. By using a mouse model lacking STAT3 in muscle, we demonstrate that skeletal muscle mitochondrial and physiological function, both in vivo and ex vivo, is not impacted by the loss of STAT3.
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Affiliation(s)
- Jessica R Dent
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Byron Hetrick
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Shahriar Tahvilian
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Abha Sathe
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Keenan Greyslak
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Samuel A LaBarge
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Kristoffer Svensson
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Carrie E McCurdy
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California.,Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California
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12
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McGee SL, Hargreaves M. Epigenetics and Exercise. Trends Endocrinol Metab 2019; 30:636-645. [PMID: 31279665 DOI: 10.1016/j.tem.2019.06.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/06/2019] [Accepted: 06/07/2019] [Indexed: 01/12/2023]
Abstract
Epigenetics can be defined as 'the structural adaptation of chromosomal regions so as to register, signal, or perpetuate altered activity states.' Increased transcription of key regulatory, metabolic, and myogenic genes is an early response to exercise and is important in mediating subsequent adaptations in skeletal muscle. DNA hypomethylation and histone hyperacetylation are emerging as important crucial events for increased transcription. The complex interactions between multiple epigenetic modifications and their regulation by metabolic changes and signaling events during exercise, with implications for enhanced understanding of the acute and chronic adaptations to exercise, are questions for further investigation.
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Affiliation(s)
- Sean L McGee
- Metabolic Research Unit, School of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong Waurn Ponds, VIC 3216, Australia.
| | - Mark Hargreaves
- Department of Physiology, The University of Melbourne, VIC 3010, Australia.
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13
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Martins VF, Dent JR, Svensson K, Tahvilian S, Begur M, Lakkaraju S, Buckner EH, LaBarge SA, Hetrick B, McCurdy CE, Schenk S. Germline or inducible knockout of p300 or CBP in skeletal muscle does not alter insulin sensitivity. Am J Physiol Endocrinol Metab 2019; 316:E1024-E1035. [PMID: 30888860 PMCID: PMC6620570 DOI: 10.1152/ajpendo.00497.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Akt is a critical mediator of insulin-stimulated glucose uptake in skeletal muscle. The acetyltransferases, E1A binding protein p300 (p300) and cAMP response element-binding protein binding protein (CBP) are phosphorylated and activated by Akt, and p300/CBP can acetylate and inactivate Akt, thus giving rise to a possible Akt-p300/CBP axis. Our objective was to determine the importance of p300 and CBP to skeletal muscle insulin sensitivity. We used Cre-LoxP methodology to generate mice with germline [muscle creatine kinase promoter (P-MCK and C-MCK)] or inducible [tamoxifen-activated, human skeletal actin promoter (P-iHSA and C-iHSA)] knockout of p300 or CBP. A subset of P-MCK and C-MCK mice were switched to a calorie-restriction diet (60% of ad libitum intake) or high-fat diet at 10 wk of age. For P-iHSA and C-iHSA mice, knockout was induced at 10 wk of age. At 13-15 wk of age, we measured whole-body energy expenditure, oral glucose tolerance, and/or ex vivo skeletal muscle insulin sensitivity. Although p300 and CBP protein abundance and mRNA expression were reduced 55%-90% in p300 and CBP knockout mice, there were no genotype differences in energy expenditure or fasting glucose and insulin concentrations. Moreover, neither loss of p300 or CBP impacted oral glucose tolerance or skeletal muscle insulin sensitivity, nor did their loss impact alterations in these parameters in response to a calorie restriction or high-fat diet. Muscle-specific loss of either p300 or CBP, be it germline or in adulthood, does not impact energy expenditure, glucose tolerance, or skeletal muscle insulin action.
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Affiliation(s)
- Vitor F Martins
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California
| | - Jessica R Dent
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Kristoffer Svensson
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Shahriar Tahvilian
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Maedha Begur
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Shivani Lakkaraju
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Elisa H Buckner
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Samuel A LaBarge
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Byron Hetrick
- Department of Human Physiology, University of Oregon , Eugene, Oregon
| | - Carrie E McCurdy
- Department of Human Physiology, University of Oregon , Eugene, Oregon
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California
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14
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Sin TK, Zhu JZ, Zhang G, Li YP. p300 Mediates Muscle Wasting in Lewis Lung Carcinoma. Cancer Res 2019; 79:1331-1342. [PMID: 30705122 PMCID: PMC6445764 DOI: 10.1158/0008-5472.can-18-1653] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/28/2018] [Accepted: 01/28/2019] [Indexed: 12/21/2022]
Abstract
C/EBPβ is a key mediator of cancer-induced skeletal muscle wasting. However, the signaling mechanisms that activate C/EBPβ in the cancer milieu are poorly defined. Here, we report cancer-induced muscle wasting requires the transcriptional cofactor p300, which is critical for the activation of C/EBPβ. Conditioned media from diverse types of tumor cells as well as recombinant HSP70 and HSP90 provoked rapid acetylation of C/EBPβ in myotubes, particularly at its Lys39 residue. Overexpression of C/EBPβ with mutated Lys39 impaired Lewis lung carcinoma (LLC)-induced activation of the C/EBPβ-dependent catabolic response, which included upregulation of E3 ligases UBR2 and atrogin1/MAFbx, increased LC3-II, and loss of muscle proteins both in myotubes and mouse muscle. Silencing p300 in myotubes or overexpressing a dominant negative p300 mutant lacking acetyltransferase activity in mouse muscle attenuated LLC tumor-induced muscle catabolism. Administration of pharmacologic p300 inhibitor C646, but not PCAF/GCN5 inhibitor CPTH6, spared LLC tumor-bearing mice from muscle wasting. Furthermore, mice with muscle-specific p300 knockout were resistant to LLC tumor-induced muscle wasting. These data suggest that p300 is a key mediator of LLC tumor-induced muscle wasting whose acetyltransferase activity may be targeted for therapeutic benefit in this disease. SIGNIFICANCE: These findings demonstrate that tumor-induced muscle wasting in mice is abrogated by knockout, mutation of Lys39 or Asp1399, and pharmacologic inhibition of p300.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/7/1331/F1.large.jpg.
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Affiliation(s)
- Thomas K Sin
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
| | - James Z Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Guohua Zhang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas.
| | - Yi-Ping Li
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas.
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15
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Manzanares G, Brito-da-Silva G, Gandra PG. Voluntary wheel running: patterns and physiological effects in mice. ACTA ACUST UNITED AC 2018; 52:e7830. [PMID: 30539969 PMCID: PMC6301263 DOI: 10.1590/1414-431x20187830] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/09/2018] [Indexed: 11/22/2022]
Abstract
Exercise can prevent and improve the pathophysiology of diseases and promote healthy aging. Thus, understanding the mechanisms that regulate the beneficial effects of exercise may lead to the development of new strategies to enhance quality of life and to counteract chronic diseases. Voluntary wheel running is an interesting model to study the effects of exercise in mice. Compared to forced treadmill exercise, voluntary wheel running presents several advantages such as: 1) running pattern is similar to natural running behavior of mice; 2) it is performed under non-stressed conditions, according to the rhythmicity of the animal; 3) it does not require direct interference from the researcher, and can be easily applied in long-term studies. Mice run spontaneously when given access to running wheels, for a total distance of ∼4 to 20 km per day and a total activity time of ∼3 to 7 hours a day. Hence, voluntary wheel running can result in robust endurance-like adaptation in skeletal and cardiac muscles and protect from sarcopenia. However, due to the lack of control over exercise parameters in voluntary exercise models, it is important for the researcher to understand the patterns and variability of wheel running in mice, as well as the factors that can affect voluntary running activity. Overall, voluntary wheel running in mice is a very interesting approach to study the chronic adaptation to exercise, analyze the effects of exercise, and test exercise capacity in different experimental models.
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Affiliation(s)
- G Manzanares
- Departamento de Bioquímica e Biologia Tecidual, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brasil
| | - G Brito-da-Silva
- Departamento de Bioquímica e Biologia Tecidual, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brasil
| | - P G Gandra
- Departamento de Bioquímica e Biologia Tecidual, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brasil
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16
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Zhang HL, Zhang HJ, Guo XT. Experimental study on Taijiquan exercise improving university students’ cognitive function. COGN SYST RES 2018. [DOI: 10.1016/j.cogsys.2018.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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17
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Svensson K, Dent JR, Tahvilian S, Martins VF, Sathe A, Ochala J, Patel MS, Schenk S. Defining the contribution of skeletal muscle pyruvate dehydrogenase α1 to exercise performance and insulin action. Am J Physiol Endocrinol Metab 2018; 315:E1034-E1045. [PMID: 30153068 PMCID: PMC6293170 DOI: 10.1152/ajpendo.00241.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The pyruvate dehydrogenase complex (PDC) converts pyruvate to acetyl-CoA and is an important control point for carbohydrate (CHO) oxidation. However, the importance of the PDC and CHO oxidation to muscle metabolism and exercise performance, particularly during prolonged or high-intensity exercise, has not been fully defined especially in mature skeletal muscle. To this end, we determined whether skeletal muscle-specific loss of pyruvate dehydrogenase alpha 1 ( Pdha1), which is a critical subunit of the PDC, impacts resting energy metabolism, exercise performance, or metabolic adaptation to high-fat diet (HFD) feeding. For this, we generated a tamoxifen (TMX)-inducible Pdha1 knockout (PDHmKO) mouse, in which PDC activity is temporally and specifically ablated in adult skeletal muscle. We assessed energy expenditure, ex vivo muscle contractile performance, and endurance exercise capacity in PDHmKO mice and wild-type (WT) littermates. Additionally, we studied glucose homeostasis and insulin sensitivity in muscle after 12 wk of HFD feeding. TMX administration largely ablated PDHα in skeletal muscle of adult PDHmKO mice but did not impact energy expenditure, muscle contractile function, or low-intensity exercise performance. Additionally, there were no differences in muscle insulin sensitivity or body composition in PDHmKO mice fed a control or HFD, as compared with WT mice. However, exercise capacity during high-intensity exercise was severely impaired in PDHmKO mice, in parallel with a large increase in plasma lactate concentration. In conclusion, although skeletal muscle PDC is not a major contributor to resting energy expenditure or long-duration, low-intensity exercise performance, it is necessary for optimal performance during high-intensity exercise.
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Affiliation(s)
- Kristoffer Svensson
- Department of Orthopaedic Surgery, University of California San Diego , La Jolla, California
| | - Jessica R Dent
- Department of Orthopaedic Surgery, University of California San Diego , La Jolla, California
| | - Shahriar Tahvilian
- Department of Orthopaedic Surgery, University of California San Diego , La Jolla, California
| | - Vitor F Martins
- Department of Orthopaedic Surgery, University of California San Diego , La Jolla, California
| | - Abha Sathe
- Department of Orthopaedic Surgery, University of California San Diego , La Jolla, California
| | - Julien Ochala
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, King's College London , London , United Kingdom
| | - Mulchand S Patel
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo , Buffalo, New York
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California San Diego , La Jolla, California
- Biomedical Sciences Graduate Program, University of California San Diego , La Jolla, California
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18
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Martins VF, Tahvilian S, Kang JH, Svensson K, Hetrick B, Chick WS, Schenk S, McCurdy CE. Calorie Restriction-Induced Increase in Skeletal Muscle Insulin Sensitivity Is Not Prevented by Overexpression of the p55α Subunit of Phosphoinositide 3-Kinase. Front Physiol 2018; 9:789. [PMID: 29997524 PMCID: PMC6030672 DOI: 10.3389/fphys.2018.00789] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/06/2018] [Indexed: 01/26/2023] Open
Abstract
Introduction: The Phosphoinositide 3-kinase (PI3K) signaling pathway plays an important role in skeletal muscle insulin-stimulated glucose uptake. While whole-body and tissue specific knockout (KO) of individual or combinations of the regulatory subunits of PI3K (p85α, p55α, and p50α or p85β); increase insulin sensitivity, no study has examined whether increasing the expression of the individual regulatory subunits would inhibit insulin action in vivo. Therefore, the objective of this study was to determine whether skeletal muscle-specific overexpression of the p55α regulatory subunit of PI3K impairs skeletal muscle insulin sensitivity, or prevents its enhancement by caloric restriction. Methods: We developed a novel "floxed" mouse that, through the Cre-LoxP approach, allows for tamoxifen (TMX)-inducible and skeletal muscle-specific overexpression of the p55α subunit of PI3K (referred to as, 'p55α-mOX'). Beginning at 10 weeks of age, p55α-mOX mice and their floxed littermates (referred to as wildtype [WT]) either continued with free access to food (ad libitum; AL), or were switched to a calorie restricted diet (CR; 60% of AL intake) for 20 days. We measured body composition, whole-body energy expenditure, oral glucose tolerance and ex vivo skeletal muscle insulin sensitivity in isolated soleus and extensor digitorum longus muscles using the 2-deoxy-glucose (2DOG) uptake method. Results: p55α mRNA and protein expression was increased ∼2 fold in muscle from p55α-mOX versus WT mice. There were no differences in energy expenditure, total activity, or food intake of AL-fed mice between genotypes. Body weight, fat and lean mass, tissue weights, and fasting glucose and insulin were comparable between p55α-mOX and WT mice on AL, and were decreased equally by CR. Interestingly, overexpression of p55α did not impair oral glucose tolerance or skeletal muscle insulin signaling or sensitivity, nor did it impact the ability of CR to enhance these parameters. Conclusion: Skeletal muscle-specific overexpression of p55α does not impact skeletal muscle insulin action, suggesting that p85α and/or p50α may be more important regulators of skeletal muscle insulin signaling and sensitivity.
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Affiliation(s)
- Vitor F. Martins
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, CA, United States
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, United States
| | - Shahriar Tahvilian
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, CA, United States
| | - Ji H. Kang
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, CA, United States
| | - Kristoffer Svensson
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, CA, United States
| | - Byron Hetrick
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Wallace S. Chick
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, CA, United States
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, United States
| | - Carrie E. McCurdy
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
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19
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Dent JR, Martins VF, Svensson K, LaBarge SA, Schlenk NC, Esparza MC, Buckner EH, Meyer GA, Hamilton DL, Schenk S, Philp A. Muscle-specific knockout of general control of amino acid synthesis 5 (GCN5) does not enhance basal or endurance exercise-induced mitochondrial adaptation. Mol Metab 2017; 6:1574-1584. [PMID: 29111103 PMCID: PMC5699915 DOI: 10.1016/j.molmet.2017.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 09/29/2017] [Accepted: 10/10/2017] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE Lysine acetylation is an important post-translational modification that regulates metabolic function in skeletal muscle. The acetyltransferase, general control of amino acid synthesis 5 (GCN5), has been proposed as a regulator of mitochondrial biogenesis via its inhibitory action on peroxisome proliferator activated receptor-γ coactivator-1α (PGC-1α). However, the specific contribution of GCN5 to skeletal muscle metabolism and mitochondrial adaptations to endurance exercise in vivo remain to be defined. We aimed to determine whether loss of GCN5 in skeletal muscle enhances mitochondrial density and function, and the adaptive response to endurance exercise training. METHODS We used Cre-LoxP methodology to generate mice with muscle-specific knockout of GCN5 (mKO) and floxed, wildtype (WT) littermates. We measured whole-body energy expenditure, as well as markers of mitochondrial density, biogenesis, and function in skeletal muscle from sedentary mice, and mice that performed 20 days of voluntary endurance exercise training. RESULTS Despite successful knockdown of GCN5 activity in skeletal muscle of mKO mice, whole-body energy expenditure as well as skeletal muscle mitochondrial abundance and maximal respiratory capacity were comparable between mKO and WT mice. Further, there were no genotype differences in endurance exercise-mediated mitochondrial biogenesis or increases in PGC-1α protein content. CONCLUSION These results demonstrate that loss of GCN5 in vivo does not promote metabolic remodeling in mouse skeletal muscle.
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Affiliation(s)
- Jessica R Dent
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, UK
| | - Vitor F Martins
- Department of Orthopaedic Surgery, University of California, La Jolla, San Diego, CA, USA; Biomedical Sciences Graduate Program, University of California, La Jolla, San Diego, CA, USA
| | - Kristoffer Svensson
- Department of Orthopaedic Surgery, University of California, La Jolla, San Diego, CA, USA
| | - Samuel A LaBarge
- Department of Orthopaedic Surgery, University of California, La Jolla, San Diego, CA, USA
| | - Noah C Schlenk
- Department of Orthopaedic Surgery, University of California, La Jolla, San Diego, CA, USA
| | - Mary C Esparza
- Department of Orthopaedic Surgery, University of California, La Jolla, San Diego, CA, USA
| | - Elisa H Buckner
- Department of Orthopaedic Surgery, University of California, La Jolla, San Diego, CA, USA
| | - Gretchen A Meyer
- Program in Physical Therapy, Washington University School of Medicine, St Louis, MO, USA
| | | | - Simon Schenk
- Department of Orthopaedic Surgery, University of California, La Jolla, San Diego, CA, USA; Biomedical Sciences Graduate Program, University of California, La Jolla, San Diego, CA, USA.
| | - Andrew Philp
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, UK.
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20
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Svensson K, LaBarge SA, Martins VF, Schenk S. Temporal overexpression of SIRT1 in skeletal muscle of adult mice does not improve insulin sensitivity or markers of mitochondrial biogenesis. Acta Physiol (Oxf) 2017; 221:193-203. [PMID: 28544355 DOI: 10.1111/apha.12897] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 04/23/2017] [Accepted: 05/11/2017] [Indexed: 12/23/2022]
Abstract
AIMS Activation of the NAD+ dependent protein deacetylase SIRT1 has been proposed as a therapeutic strategy to treat mitochondrial dysfunction and insulin resistance in skeletal muscle. However, lifelong overexpression of SIRT1 in skeletal muscle does not improve parameters of mitochondrial function and insulin sensitivity. In this study, we investigated whether temporal overexpression of SIRT1 in muscle of adult mice would affect skeletal muscle mitochondrial function and insulin sensitivity. METHODS To circumvent potential effects of germline SIRT1 overexpression, we utilized an inducible model of SIRT1 overexpression in skeletal muscle of adult mice (i-mOX). Insulin sensitivity was assessed by 2-deoxyglucose uptake, muscle maximal respiratory function by high-resolution respirometry and systemic energy expenditure was assessed by whole body calorimetry. RESULTS Although SIRT1 was highly, and specifically, overexpressed in skeletal muscle of i-mOX compared to WT mice, glucose tolerance and skeletal muscle insulin sensitivity were comparable between genotypes. Additionally, markers of mitochondrial biogenesis, muscle maximal respiratory function and whole-body oxygen consumption were also unaffected by SIRT1 overexpression. CONCLUSION These results support previous work demonstrating that induction of SIRT1 in skeletal muscle, either at birth or in adulthood, does not impact muscle insulin action or mitochondrial function.
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Affiliation(s)
- K. Svensson
- Department of Orthopaedic Surgery; University of California San Diego; La Jolla CA USA
| | - S. A. LaBarge
- Department of Orthopaedic Surgery; University of California San Diego; La Jolla CA USA
| | - V. F. Martins
- Department of Orthopaedic Surgery; University of California San Diego; La Jolla CA USA
| | - S. Schenk
- Department of Orthopaedic Surgery; University of California San Diego; La Jolla CA USA
- Biomedical Sciences Graduate Program; University of California San Diego; La Jolla CA USA
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