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Zhang D, Tao J, Zhang X, Ma X, Li C, Li H, Li W, Chen J, Liu H. Novel Pro-myogenic Factor Neoruscogenin Induces Muscle Fiber Hypertrophy by Inhibiting MSTN Maturation and Activating the Akt/mTOR Pathway. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:499-511. [PMID: 36563293 DOI: 10.1021/acs.jafc.2c06527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Neoruscogenin is a plant-origin sapogenin that has the potential to modulate muscle growth among the small-molecule compounds that we previously predicted by artificial intelligence to target myostatin (MSTN). This study aimed to elucidate the biological role of neoruscogenin on muscle growth and its relationship with MSTN. Using molecular biological techniques, we found that neoruscogenin inhibited MSTN maturation, thereby repressing its signal transduction; further facilitated protein synthesis metabolism and reduced protein degradation metabolism, ultimately promoting the differentiation of myoblasts and hypertrophy of muscle fibers; and had the effect of repairing muscle injury. This study enriched the biological functions of neoruscogenin and provided a theoretical basis for the treatment of human myopathy and its application in the livestock industry.
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Affiliation(s)
- Dingding Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jingli Tao
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Xuan Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiangfei Ma
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Chengyu Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Hongmin Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Weijian Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jie Chen
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Honglin Liu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
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Myokines and Resistance Training: A Narrative Review. Int J Mol Sci 2022; 23:ijms23073501. [PMID: 35408868 PMCID: PMC8998961 DOI: 10.3390/ijms23073501] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 01/27/2023] Open
Abstract
In the last few years, the muscular system has gained attention due to the discovery of the muscle-secretome and its high potency for retaining or regaining health. These cytokines, described as myokines, released by the working muscle, are involved in anti-inflammatory, metabolic and immunological processes. These are able to influence human health in a positive way and are a target of research in metabolic diseases, cancer, neurological diseases, and other non-communicable diseases. Therefore, different types of exercise training were investigated in the last few years to find associations between exercise, myokines and their effects on human health. Particularly, resistance training turned out to be a powerful stimulus to enhance myokine release. As there are different types of resistance training, different myokines are stimulated, depending on the mode of training. This narrative review gives an overview about resistance training and how it can be utilized to stimulate myokine production in order to gain a certain health effect. Finally, the question of why resistance training is an important key regulator in human health will be discussed.
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Abdel-Raouf KMA, Rezgui R, Stefanini C, Teo JCM, Christoforou N. Transdifferentiation of Human Fibroblasts into Skeletal Muscle Cells: Optimization and Assembly into Engineered Tissue Constructs through Biological Ligands. BIOLOGY 2021; 10:biology10060539. [PMID: 34208436 PMCID: PMC8235639 DOI: 10.3390/biology10060539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Engineered human skeletal muscle tissue is a platform tool that can help scientists and physicians better understand human physiology, pharmacology, and disease modeling. Over the past few years this area of research has been actively being pursued by many labs worldwide. Significant challenges remain, including accessing an adequate cell source, and achieving proper physiological-like architecture of the engineered tissue. To address cell resourcing we aimed at further optimizing a process called transdifferentiation which involves the direct conversion of fibroblasts into skeletal muscle cells. The opportunity here is that fibroblasts are readily available and can be expanded sufficiently to meet the needs of a tissue engineering approach. Additionally, we aimed to demonstrate the applicability of transdifferentiation in assembling tissue engineered skeletal muscle. We implemented a screening process of protein ligands in an effort to refine transdifferentiation, and identified that most proteins resulted in a deficit in transdifferentiation efficiency, although one resulted in robust expansion of cultured cells. We were also successful in assembling engineered constructs consisting of transdifferentiated cells. Future directives involve demonstrating that the engineered tissues are capable of contractile and functional activity, and pursuit of optimizing factors such as electrical and chemical exposure, towards achieving physiological parameters observed in human muscle. Abstract The development of robust skeletal muscle models has been challenging due to the partial recapitulation of human physiology and architecture. Reliable and innovative 3D skeletal muscle models recently described offer an alternative that more accurately captures the in vivo environment but require an abundant cell source. Direct reprogramming or transdifferentiation has been considered as an alternative. Recent reports have provided evidence for significant improvements in the efficiency of derivation of human skeletal myotubes from human fibroblasts. Herein we aimed at improving the transdifferentiation process of human fibroblasts (tHFs), in addition to the differentiation of murine skeletal myoblasts (C2C12), and the differentiation of primary human skeletal myoblasts (HSkM). Differentiating or transdifferentiating cells were exposed to single or combinations of biological ligands, including Follistatin, GDF8, FGF2, GDF11, GDF15, hGH, TMSB4X, BMP4, BMP7, IL6, and TNF-α. These were selected for their critical roles in myogenesis and regeneration. C2C12 and tHFs displayed significant differentiation deficits when exposed to FGF2, BMP4, BMP7, and TNF-α, while proliferation was significantly enhanced by FGF2. When exposed to combinations of ligands, we observed consistent deficit differentiation when TNF-α was included. Finally, our direct reprogramming technique allowed for the assembly of elongated, cross-striated, and aligned tHFs within tissue-engineered 3D skeletal muscle constructs. In conclusion, we describe an efficient system to transdifferentiate human fibroblasts into myogenic cells and a platform for the generation of tissue-engineered constructs. Future directions will involve the evaluation of the functional characteristics of these engineered tissues.
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Affiliation(s)
- Khaled M. A. Abdel-Raouf
- Department of Biomedical Engineering, Khalifa University, Abu Dhabi 127788, United Arab Emirates;
- Department of Biology, American University in Cairo, New Cairo 11835, Egypt
- Correspondence: (K.M.A.A.-R.); (N.C.)
| | - Rachid Rezgui
- Core Technology Platforms, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates;
| | - Cesare Stefanini
- Department of Biomedical Engineering, Khalifa University, Abu Dhabi 127788, United Arab Emirates;
- Healthcare Engineering Innovation Center, Khalifa University, Abu Dhabi 127788, United Arab Emirates
| | - Jeremy C. M. Teo
- Department of Mechanical and Biomedical Engineering, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates;
| | - Nicolas Christoforou
- Pfizer Inc., Rare Disease Research Unit, 610 Main Street, Cambridge, MA 02139, USA
- Correspondence: (K.M.A.A.-R.); (N.C.)
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Ciecierska A, Motyl T, Sadkowski T. Transcriptomic profile of semitendinosus muscle of bulls of different breed and performance. J Appl Genet 2020; 61:581-592. [PMID: 32851594 PMCID: PMC7652804 DOI: 10.1007/s13353-020-00577-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 06/29/2020] [Accepted: 08/11/2020] [Indexed: 12/16/2022]
Abstract
The aim of the study was to compare the transcriptomic profiles of fully differentiated skeletal muscle derived from bulls belonging to different breeds of varying performance. Microarray analyses were performed to determine the differences in the expression profiles of genes between semitendinosus muscles of 15-month-old beef-breed bulls (Limousin—LIM and Hereford—HER) and dairy-breed bulls (Holstein Friesian—HF). These analyses allowed for the identification of those genes the expression of which is similar and characteristic of fully differentiated muscle in beef breeds, but differs in skeletal muscle of a typical dairy breed. The analysis revealed 463 transcripts showing similar expression in the semitendinosus muscle of beef breeds (LIM/HER), in comparison with the dairy breed (HF). Among the identified genes, 227 were upregulated and 236 were downregulated in beef breeds. The ontological analyses revealed that the largest group of genes similarly expressed in LIM and HER was involved in the processes of protein metabolism and development of muscle organ. In beef breeds, some genes involved in protein synthesis and proteolysis showed an upregulation, including ctsd, ctsf, fhl2, fhl3, fst, sirt1, and trim63, whereas some were downregulated, including bmpr1a, bmpr2, mstn, smad2, hspa8, gsk3β, and tgfβ2. The expression of the chosen genes was confirmed by RT-qPCR technique. Thus, it can be assumed that the identified genes involved in the regulation of growth and development of muscle tissue and the processes of protein metabolism in the examined cattle breeds may be responsible for the greater gain of muscle mass in beef-breed bulls.
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Affiliation(s)
- Anna Ciecierska
- Department of Human Nutrition, Institute of Human Nutrition Sciences, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159C, 02-776, Warsaw, Poland
| | - Tomasz Motyl
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Tomasz Sadkowski
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776, Warsaw, Poland.
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Borok MJ, Mademtzoglou D, Relaix F. Bu-M-P-ing Iron: How BMP Signaling Regulates Muscle Growth and Regeneration. J Dev Biol 2020; 8:jdb8010004. [PMID: 32053985 PMCID: PMC7151139 DOI: 10.3390/jdb8010004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/16/2022] Open
Abstract
The bone morphogenetic protein (BMP) pathway is best known for its role in promoting bone formation, however it has been shown to play important roles in both development and regeneration of many different tissues. Recent work has shown that the BMP proteins have a number of functions in skeletal muscle, from embryonic to postnatal development. Furthermore, complementary studies have recently demonstrated that specific components of the pathway are required for efficient muscle regeneration.
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Affiliation(s)
- Matthew J Borok
- Inserm, IMRB U955-E10, 94010 Créteil, France; (M.J.B.); (D.M.)
- Faculté de santé, Université Paris Est, 94000 Creteil, France
| | - Despoina Mademtzoglou
- Inserm, IMRB U955-E10, 94010 Créteil, France; (M.J.B.); (D.M.)
- Faculté de santé, Université Paris Est, 94000 Creteil, France
| | - Frederic Relaix
- Inserm, IMRB U955-E10, 94010 Créteil, France; (M.J.B.); (D.M.)
- Faculté de santé, Université Paris Est, 94000 Creteil, France
- Ecole Nationale Veterinaire d’Alfort, 94700 Maison Alfort, France
- Etablissement Français du Sang, 94017 Créteil, France
- APHP, Hopitaux Universitaires Henri Mondor, DHU Pepsy & Centre de Référence des Maladies Neuromusculaires GNMH, 94000 Créteil, France
- Correspondence: ; Tel.: +33-149-813-940
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Bloise E, Ciarmela P, Dela Cruz C, Luisi S, Petraglia F, Reis FM. Activin A in Mammalian Physiology. Physiol Rev 2019; 99:739-780. [DOI: 10.1152/physrev.00002.2018] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Activins are dimeric glycoproteins belonging to the transforming growth factor beta superfamily and resulting from the assembly of two beta subunits, which may also be combined with alpha subunits to form inhibins. Activins were discovered in 1986 following the isolation of inhibins from porcine follicular fluid, and were characterized as ovarian hormones that stimulate follicle stimulating hormone (FSH) release by the pituitary gland. In particular, activin A was shown to be the isoform of greater physiological importance in humans. The current understanding of activin A surpasses the reproductive system and allows its classification as a hormone, a growth factor, and a cytokine. In more than 30 yr of intense research, activin A was localized in female and male reproductive organs but also in other organs and systems as diverse as the brain, liver, lung, bone, and gut. Moreover, its roles include embryonic differentiation, trophoblast invasion of the uterine wall in early pregnancy, and fetal/neonate brain protection in hypoxic conditions. It is now recognized that activin A overexpression may be either cytostatic or mitogenic, depending on the cell type, with important implications for tumor biology. Activin A also regulates bone formation and regeneration, enhances joint inflammation in rheumatoid arthritis, and triggers pathogenic mechanisms in the respiratory system. In this 30-yr review, we analyze the evidence for physiological roles of activin A and the potential use of activin agonists and antagonists as therapeutic agents.
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Affiliation(s)
- Enrrico Bloise
- Department of Morphology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy; Department of Obstetrics and Gynecology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Molecular and Developmental Medicine, Obstetrics and Gynecological Clinic, University of Siena, Siena, Italy; and Department of Biomedical, Experimental and Clinical Sciences, Division of Obstetrics and
| | - Pasquapina Ciarmela
- Department of Morphology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy; Department of Obstetrics and Gynecology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Molecular and Developmental Medicine, Obstetrics and Gynecological Clinic, University of Siena, Siena, Italy; and Department of Biomedical, Experimental and Clinical Sciences, Division of Obstetrics and
| | - Cynthia Dela Cruz
- Department of Morphology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy; Department of Obstetrics and Gynecology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Molecular and Developmental Medicine, Obstetrics and Gynecological Clinic, University of Siena, Siena, Italy; and Department of Biomedical, Experimental and Clinical Sciences, Division of Obstetrics and
| | - Stefano Luisi
- Department of Morphology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy; Department of Obstetrics and Gynecology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Molecular and Developmental Medicine, Obstetrics and Gynecological Clinic, University of Siena, Siena, Italy; and Department of Biomedical, Experimental and Clinical Sciences, Division of Obstetrics and
| | - Felice Petraglia
- Department of Morphology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy; Department of Obstetrics and Gynecology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Molecular and Developmental Medicine, Obstetrics and Gynecological Clinic, University of Siena, Siena, Italy; and Department of Biomedical, Experimental and Clinical Sciences, Division of Obstetrics and
| | - Fernando M. Reis
- Department of Morphology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy; Department of Obstetrics and Gynecology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Molecular and Developmental Medicine, Obstetrics and Gynecological Clinic, University of Siena, Siena, Italy; and Department of Biomedical, Experimental and Clinical Sciences, Division of Obstetrics and
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Rudar M, Fiorotto ML, Davis TA. Regulation of Muscle Growth in Early Postnatal Life in a Swine Model. Annu Rev Anim Biosci 2018; 7:309-335. [PMID: 30388025 DOI: 10.1146/annurev-animal-020518-115130] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Skeletal muscle growth during the early postnatal period is rapid in the pig and dependent on the capacity of muscle to respond to anabolic and catabolic stimuli. Muscle mass is driven by the balance between protein synthesis and degradation. Among these processes, muscle protein synthesis in the piglet is exceptionally sensitive to the feeding-induced postprandial changes in insulin and amino acids, whereas muscle protein degradation is affected only during specific catabolic states. The developmental decline in the response of muscle to feeding is associated with changes in the signaling pathways located upstream and downstream of the mechanistic target of rapamycin protein complex. Additionally, muscle growth is supported by an accretion of nuclei derived from satellite cells. Activated satellite cells undergo proliferation, differentiation, and fusion with adjacent growing muscle fibers. Enhancing early muscle growth through modifying protein synthesis, degradation, and satellite cell activity is key to maximizing performance, productivity, and lifelong pig health.
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Affiliation(s)
- Marko Rudar
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA; , ,
| | - Marta L Fiorotto
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA; , ,
| | - Teresa A Davis
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA; , ,
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Fiorotto ML, Davis TA. Critical Windows for the Programming Effects of Early-Life Nutrition on Skeletal Muscle Mass. NESTLE NUTRITION INSTITUTE WORKSHOP SERIES 2018; 89:25-35. [PMID: 29991029 DOI: 10.1159/000486490] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Skeletal myogenesis begins in the embryo with proliferation and differentiation of muscle progenitor cells that ultimately fuse to form multinucleated myofibers. After midgestation, muscle growth occurs through hypertrophy of these myofibers. The most rapid growth phase occurs in the perinatal period, resulting in the expansion of muscle mass from 25% of lean mass at birth to 40-45% at maturity. These 2 phases of muscle growth are regulated by distinct molecular mechanisms engaged by extracellular cues and intracellular signaling pathways and regulatory networks they activate. Nutrients influence muscle growth by both providing the necessary substrates and eliciting extracellular cues which regulate the signal transduction pathways that control the anabolic processes of the fibers. The uniquely large capacity of immature myofibers for hypertrophy is enabled by a heightened capacity and sensitivity of protein synthesis to feeding-induced changes in plasma insulin and amino acids, and the ability to expand their myonuclear population through proliferation of muscle precursor cells (satellite cells). With maturation, satellite cells become quiescent, limiting myonuclear accretion, and the capacity of the muscles for protein anabolism progressively diminishes. Therefore, the early developmental phases represent critical windows for muscle growth which, if disrupted, result in muscle mass deficits that are unlikely to be entirely recoverable.
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Abstract
CONTEXT Follistatin is a liver-derived inhibitor of the muscle-growth inhibitor myostatin. Reduction in acute follistatin release may help explain muscle loss in liver cirrhosis. OBJECTIVE The study aimed to investigate the capacity of acute follistatin release in patients with liver cirrhosis compared to healthy control participants. DESIGN, SETTING, AND PARTICIPANTS To experimentally increase the glucagon-insulin ratio (mimicking the hormonal effect of exercise), we infused glucagon/somatostatin (to inhibit insulin secretion) and compared the acute follistatin increase in eight male cirrhosis patients with eight healthy control participants. Patients and controls received 1-hour glucagon/somatostatin and saline infusions on 2 separate days. MAIN OUTCOME MEASURE Follistatin was measured during and 5 hours after termination of infusions. RESULTS The peak follistatin change was significantly decreased in patients with liver cirrhosis compared to healthy control participants (1.9 (interquartile range, 1.4-2.5) versus 3.6 (interquartile range, 3.0-4.0), respectively; P = .003). Patients with liver cirrhosis demonstrated significantly decreased amounts of appendicular lean mass compared to healthy controls (27.6 ± 3.8 vs 34.5 ± 2.9%, respectively; P = .001). CONCLUSIONS Patients with cirrhosis show impaired capacity to acutely secrete follistatin. The decrease in acute follistatin release may contribute to the loss of muscle mass in liver cirrhosis.
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Affiliation(s)
- Anders Rasmussen Rinnov
- The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (A.R.R., P.P., B.K.P.), Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; Department of Clinical Biochemistry (P.P.), Rigshospitalet, 2100 Copenhagen, Denmark; and Gastrounit, Hvidovre Hospital (L.L.G.), University of Copenhagen, 2650 Hvidovre, Denmark
| | - Peter Plomgaard
- The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (A.R.R., P.P., B.K.P.), Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; Department of Clinical Biochemistry (P.P.), Rigshospitalet, 2100 Copenhagen, Denmark; and Gastrounit, Hvidovre Hospital (L.L.G.), University of Copenhagen, 2650 Hvidovre, Denmark
| | - Bente Klarlund Pedersen
- The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (A.R.R., P.P., B.K.P.), Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; Department of Clinical Biochemistry (P.P.), Rigshospitalet, 2100 Copenhagen, Denmark; and Gastrounit, Hvidovre Hospital (L.L.G.), University of Copenhagen, 2650 Hvidovre, Denmark
| | - Lise Lotte Gluud
- The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (A.R.R., P.P., B.K.P.), Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; Department of Clinical Biochemistry (P.P.), Rigshospitalet, 2100 Copenhagen, Denmark; and Gastrounit, Hvidovre Hospital (L.L.G.), University of Copenhagen, 2650 Hvidovre, Denmark
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Barbé C, Kalista S, Loumaye A, Ritvos O, Lause P, Ferracin B, Thissen JP. Role of IGF-I in follistatin-induced skeletal muscle hypertrophy. Am J Physiol Endocrinol Metab 2015. [PMID: 26219865 PMCID: PMC4572457 DOI: 10.1152/ajpendo.00098.2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Follistatin, a physiological inhibitor of myostatin, induces a dramatic increase in skeletal muscle mass, requiring the type 1 IGF-I receptor/Akt/mTOR pathway. The aim of the present study was to investigate the role of IGF-I and insulin, two ligands of the IGF-I receptor, in the follistatin hypertrophic action on skeletal muscle. In a first step, we showed that follistatin increases muscle mass while being associated with a downregulation of muscle IGF-I expression. In addition, follistatin retained its full hypertrophic effect toward muscle in hypophysectomized animals despite very low concentrations of circulating and muscle IGF-I. Furthermore, follistatin did not increase muscle sensitivity to IGF-I in stimulating phosphorylation of Akt but, surprisingly, decreased it once hypertrophy was present. Taken together, these observations indicate that increased muscle IGF-I production or sensitivity does not contribute to the muscle hypertrophy caused by follistatin. Unlike low IGF-I, low insulin, as obtained by streptozotocin injection, attenuated the hypertrophic action of follistatin on skeletal muscle. Moreover, the full anabolic response to follistatin was restored in this condition by insulin but also by IGF-I infusion. Therefore, follistatin-induced muscle hypertrophy requires the activation of the insulin/IGF-I pathway by either insulin or IGF-I. When insulin or IGF-I alone is missing, follistatin retains its full anabolic effect, but when both are deficient, as in streptozotocin-treated animals, follistatin fails to stimulate muscle growth.
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Affiliation(s)
- Caroline Barbé
- Pole of Endocrinology, Diabetes and Nutrition; Institut de Recherche Expérimentale et Clinique IREC, Université Catholique de Louvain, Brussels, Belgium; and
| | - Stéphanie Kalista
- Pole of Endocrinology, Diabetes and Nutrition; Institut de Recherche Expérimentale et Clinique IREC, Université Catholique de Louvain, Brussels, Belgium; and
| | - Audrey Loumaye
- Pole of Endocrinology, Diabetes and Nutrition; Institut de Recherche Expérimentale et Clinique IREC, Université Catholique de Louvain, Brussels, Belgium; and
| | - Olli Ritvos
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Pascale Lause
- Pole of Endocrinology, Diabetes and Nutrition; Institut de Recherche Expérimentale et Clinique IREC, Université Catholique de Louvain, Brussels, Belgium; and
| | - Benjamin Ferracin
- Pole of Endocrinology, Diabetes and Nutrition; Institut de Recherche Expérimentale et Clinique IREC, Université Catholique de Louvain, Brussels, Belgium; and
| | - Jean-Paul Thissen
- Pole of Endocrinology, Diabetes and Nutrition; Institut de Recherche Expérimentale et Clinique IREC, Université Catholique de Louvain, Brussels, Belgium; and
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Ziaaldini MM, Koltai E, Csende Z, Goto S, Boldogh I, Taylor AW, Radak Z. Exercise training increases anabolic and attenuates catabolic and apoptotic processes in aged skeletal muscle of male rats. Exp Gerontol 2015; 67:9-14. [PMID: 25910622 DOI: 10.1016/j.exger.2015.04.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/18/2015] [Accepted: 04/18/2015] [Indexed: 12/20/2022]
Abstract
Aging results in significant loss of mass and function of the skeletal muscle, which negatively impacts the quality of life. In this study we investigated whether aerobic exercise training has the potential to alter anabolic and catabolic pathways in the skeletal muscle. Five and twenty eight month old rats were used in the study. Aging resulted in decreased levels of follistatin/mTOR/Akt/Erk activation and increased myostatin/Murf1/2, proteasome subunits, and protein ubiquitination levels. In addition, TNF-α, reactive oxygen species (ROS), p53, and Bax levels were increased while Bcl-2 levels were decreased in the skeletal muscle of aged rats. Six weeks of exercise training at 60% of VO2max reversed the age-associated activation of catabolic and apoptotic pathways and increased anabolic signaling. The results suggest that the age-associated loss of muscle mass and cachexia could be due to the orchestrated down-regulation of anabolic and up-regulation of catabolic and pro-apoptotic processes. These metabolic changes can be attenuated by exercise training.
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Affiliation(s)
| | - Erika Koltai
- Research Institute of Sport Science, Semmelweis University, Budapest, Hungary
| | - Zsolt Csende
- Department of Biomechanics, Semmelweis University, Budapest, Hungary
| | - Sataro Goto
- Department of Exercise Physiology, School of Health and Sport Science, Juntendo University, Chiba, Japan
| | - Istvan Boldogh
- Department of Microbiology and Immunology, Sealy Center for Molecular Medicine, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Albert W Taylor
- Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Zsolt Radak
- Research Institute of Sport Science, Semmelweis University, Budapest, Hungary.
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Rodriguez J, Vernus B, Chelh I, Cassar-Malek I, Gabillard JC, Hadj Sassi A, Seiliez I, Picard B, Bonnieu A. Myostatin and the skeletal muscle atrophy and hypertrophy signaling pathways. Cell Mol Life Sci 2014; 71:4361-71. [PMID: 25080109 PMCID: PMC11113773 DOI: 10.1007/s00018-014-1689-x] [Citation(s) in RCA: 259] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 12/16/2022]
Abstract
Myostatin, a member of the transforming growth factor-β superfamily, is a potent negative regulator of skeletal muscle growth and is conserved in many species, from rodents to humans. Myostatin inactivation can induce skeletal muscle hypertrophy, while its overexpression or systemic administration causes muscle atrophy. As it represents a potential target for stimulating muscle growth and/or preventing muscle wasting, myostatin regulation and functions in the control of muscle mass have been extensively studied. A wealth of data strongly suggests that alterations in skeletal muscle mass are associated with dysregulation in myostatin expression. Moreover, myostatin plays a central role in integrating/mediating anabolic and catabolic responses. Myostatin negatively regulates the activity of the Akt pathway, which promotes protein synthesis, and increases the activity of the ubiquitin-proteasome system to induce atrophy. Several new studies have brought new information on how myostatin may affect both ribosomal biogenesis and translation efficiency of specific mRNA subclasses. In addition, although myostatin has been identified as a modulator of the major catabolic pathways, including the ubiquitin-proteasome and the autophagy-lysosome systems, the underlying mechanisms are only partially understood. The goal of this review is to highlight outstanding questions about myostatin-mediated regulation of the anabolic and catabolic signaling pathways in skeletal muscle. Particular emphasis has been placed on (1) the cross-regulation between myostatin, the growth-promoting pathways and the proteolytic systems; (2) how myostatin inhibition leads to muscle hypertrophy; and (3) the regulation of translation by myostatin.
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Affiliation(s)
- J. Rodriguez
- INRA, UMR866 Dynamique Musculaire Et Métabolisme, Université Montpellier 1, Université Montpellier 2, 2 Place Viala, 34060 Montpellier, France
| | - B. Vernus
- INRA, UMR866 Dynamique Musculaire Et Métabolisme, Université Montpellier 1, Université Montpellier 2, 2 Place Viala, 34060 Montpellier, France
| | - I. Chelh
- INRA, VetAgro Sup, UMR1213 Herbivores, 63122 Saint-Genès-Champanelle, France
| | - I. Cassar-Malek
- INRA, VetAgro Sup, UMR1213 Herbivores, 63122 Saint-Genès-Champanelle, France
| | - J. C. Gabillard
- INRA, UR1037, Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, France
| | - A. Hadj Sassi
- INRA-USC2009, Université Bordeaux 1, Avenue des Facultés, 33405 Talence, France
| | - I. Seiliez
- INRA, UR1067 Nutrition, Métabolisme, Aquaculture, 64310 Saint-Pée-sur-Nivelle, France
| | - B. Picard
- INRA, VetAgro Sup, UMR1213 Herbivores, 63122 Saint-Genès-Champanelle, France
| | - A. Bonnieu
- INRA, UMR866 Dynamique Musculaire Et Métabolisme, Université Montpellier 1, Université Montpellier 2, 2 Place Viala, 34060 Montpellier, France
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13
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Fiorotto ML, Davis TA, Sosa HA, Villegas-Montoya C, Estrada I, Fleischmann R. Ribosome abundance regulates the recovery of skeletal muscle protein mass upon recuperation from postnatal undernutrition in mice. J Physiol 2014; 592:5269-86. [PMID: 25239457 DOI: 10.1113/jphysiol.2014.279067] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Nutritionally-induced growth faltering in the perinatal period has been associated with reduced adult skeletal muscle mass; however, the mechanisms responsible for this are unclear. To identify the factors that determine the recuperative capacity of muscle mass, we studied offspring of FVB mouse dams fed a protein-restricted diet during gestation (GLP) or pups suckled from postnatal day 1 (PN1) to PN11 (E-UN), or PN11 to PN22 (L-UN) on protein-restricted or control dams. All pups were refed under control conditions following the episode of undernutrition. Before refeeding, and 2, 7 and 21 days later, muscle protein synthesis was measured in vivo. There were no long-term deficits in protein mass in GLP and E-UN offspring, but in L-UN offspring muscle protein mass remained significantly smaller even after 18 months (P < 0.001). E-UN differed from L-UN offspring by their capacity to upregulate postprandial muscle protein synthesis when refed (P < 0.001), a difference that was attributable to a transient increase in ribosomal abundance, i.e. translational capacity, in E-UN offspring (P < 0.05); translational efficiency was similar across dietary treatments. The postprandial phosphorylation of Akt and extracellular signal-regulated protein kinases were similar among treatments. However, activation of the ribosomal S6 kinase 1 via mTOR (P < 0.02), and total upstream binding factor abundance were significantly greater in E-UN than L-UN offspring (P < 0.02). The results indicate that the capacity of muscles to recover following perinatal undernutrition depends on developmental age as this establishes whether ribosome abundance can be enhanced sufficiently to promote the protein synthesis rates required to accelerate protein deposition for catch-up growth.
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Affiliation(s)
- Marta L Fiorotto
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Teresa A Davis
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Horacio A Sosa
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Carolina Villegas-Montoya
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Irma Estrada
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Ryan Fleischmann
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
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Wolf S, Hagl B, Kappler R. Identification of BMP2 as an epigenetically silenced growth inhibitor in rhabdomyosarcoma. Int J Oncol 2014; 44:1727-35. [PMID: 24585058 DOI: 10.3892/ijo.2014.2312] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/06/2014] [Indexed: 11/06/2022] Open
Abstract
Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma of infancy and although therapy has improved over the years, mortality is still fairly high. The establishment of new treatments has been hampered by the limited knowledge of the molecular mechanisms driving development of RMS. One characteristic of cancer cells is aberrant DNA methylation, which could lead to silencing of tumor suppressor genes. However, only a few epigenetically silenced genes have been described in RMS so far. We performed an expression profiling analysis of three RMS cell lines that were treated with the demethylating agent 5'-aza-2'-deoxycytidine (5-Aza‑dC) facilitating re-expression of epigenetically silenced genes. This treatment induced the gene BMP2 (bone morphogenetic protein 2) throughout all cell lines. Detailed methylation analysis of CpG sites in the BMP2 promoter region by bisulfite sequencing and methylation-specific PCR revealed that a high degree of DNA methylation is causatively associated with the suppression of BMP2 in RMS cells. Consequently, treatment of the RMS cell lines with 5-Aza-dC resulted in DNA demethylation of the BMP2 promoter, most prominently in alveolar RMS. Supplementation of recombinant human BMP2 (rhBMP2) led to a reduced viability of RMS cells. Altogether, these findings suggest that suppression of BMP2 by epigenetic silencing may play a critical role in the genesis of RMS, thereby providing a rationale for the development of a new treatment strategy for RMS.
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Affiliation(s)
- Sebastian Wolf
- Department of Pediatric Surgery, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University Munich, D-80337 Munich, Germany
| | - Beate Hagl
- Department of Pediatric Surgery, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University Munich, D-80337 Munich, Germany
| | - Roland Kappler
- Department of Pediatric Surgery, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University Munich, D-80337 Munich, Germany
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15
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Winbanks CE, Chen JL, Qian H, Liu Y, Bernardo BC, Beyer C, Watt KI, Thomson RE, Connor T, Turner BJ, McMullen JR, Larsson L, McGee SL, Harrison CA, Gregorevic P. The bone morphogenetic protein axis is a positive regulator of skeletal muscle mass. ACTA ACUST UNITED AC 2013; 203:345-57. [PMID: 24145169 PMCID: PMC3812980 DOI: 10.1083/jcb.201211134] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The BMP signaling pathway promotes muscle growth and inhibits muscle wasting via SMAD1/5-dependent signaling. Although the canonical transforming growth factor β signaling pathway represses skeletal muscle growth and promotes muscle wasting, a role in muscle for the parallel bone morphogenetic protein (BMP) signaling pathway has not been defined. We report, for the first time, that the BMP pathway is a positive regulator of muscle mass. Increasing the expression of BMP7 or the activity of BMP receptors in muscles induced hypertrophy that was dependent on Smad1/5-mediated activation of mTOR signaling. In agreement, we observed that BMP signaling is augmented in models of muscle growth. Importantly, stimulation of BMP signaling is essential for conservation of muscle mass after disruption of the neuromuscular junction. Inhibiting the phosphorylation of Smad1/5 exacerbated denervation-induced muscle atrophy via an HDAC4-myogenin–dependent process, whereas increased BMP–Smad1/5 activity protected muscles from denervation-induced wasting. Our studies highlight a novel role for the BMP signaling pathway in promoting muscle growth and inhibiting muscle wasting, which may have significant implications for the development of therapeutics for neuromuscular disorders.
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Affiliation(s)
- Catherine E Winbanks
- Division of Cell Signaling and Metabolism, Baker IDI Heart and Diabetes Institute, Melbourne 3004, Australia
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16
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Hulmi JJ, Oliveira BM, Silvennoinen M, Hoogaars WMH, Ma H, Pierre P, Pasternack A, Kainulainen H, Ritvos O. Muscle protein synthesis, mTORC1/MAPK/Hippo signaling, and capillary density are altered by blocking of myostatin and activins. Am J Physiol Endocrinol Metab 2013; 304:E41-50. [PMID: 23115080 DOI: 10.1152/ajpendo.00389.2012] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Loss of muscle mass and function occurs in various diseases. Myostatin blocking can attenuate muscle loss, but downstream signaling is not well known. Therefore, to elucidate associated signaling pathways, we used the soluble activin receptor IIb (sActRIIB-Fc) to block myostatin and activins in mice. Within 2 wk, the treatment rapidly increased muscle size as expected but decreased capillary density per area. sActRIIB-Fc increased muscle protein synthesis 1-2 days after the treatment correlating with enhanced mTORC1 signaling (phosphorylated rpS6 and S6K1, r = 0.8). Concurrently, increased REDD1 and eIF2Bε protein contents and phosphorylation of 4E-BP1 and AMPK was observed. In contrast, proangiogenic MAPK signaling and VEGF-A protein decreased. Hippo signaling has been characterized recently as a regulator of organ size and an important regulator of myogenesis in vitro. The phosphorylation of YAP (Yes-associated protein), a readout of activated Hippo signaling, increased after short- and longer-term myostatin and activin blocking and in exercised muscle. Moreover, dystrophic mdx mice had elevated phosphorylated and especially total YAP protein content. These results show that the blocking of myostatin and activins induce rapid skeletal muscle growth. This is associated with increased protein synthesis and mTORC1 signaling but decreased capillary density and proangiogenic signaling. It is also shown for the first time that Hippo signaling is activated in skeletal muscle after myostatin blocking and exercise and also in dystrophic muscle. This suggests that Hippo signaling may have a role in skeletal muscle in various circumstances.
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Affiliation(s)
- Juha J Hulmi
- Department of Biology of Physical Activity, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland.
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17
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Rodriguez J, Vernus B, Toubiana M, Jublanc E, Tintignac L, Leibovitch S, Bonnieu A. Myostatin inactivation increases myotube size through regulation of translational initiation machinery. J Cell Biochem 2012; 112:3531-42. [PMID: 21769921 DOI: 10.1002/jcb.23280] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Myostatin deficiency leads in skeletal muscle overgrowth but the precise molecular mechanisms underlying this hypertrophy are not well understood. In this study, to gain insight into the role of endogenous myostatin in the translational regulation, we used an in vitro model of cultured satellite cells derived from myostatin knock-out mice. Our results show that myostatin knock-out myotubes are larger than control myotubes and that this phenotype is associated with an increased activation of the Akt/mTOR signaling pathway, a known regulator of muscle hypertrophy. These results demonstrate that hypertrophy due to myostatin deficiency is preserved in vitro and suggest that myostatin deletion results in an increased protein synthesis. Accordingly, the rates of global RNA content, polysome formation and protein synthesis are all increased in myostatin-deficient myotubes while they are counteracted by the addition of recombinant myostatin. We furthermore demonstrated that genetic deletion of myostatin stimulates cap-dependent translation by positively regulating assembly of the translation preinitiation complex. Together the data indicate that myostatin controls muscle hypertrophy in part by regulating protein synthesis initiation rates, that is, translational efficiency.
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Affiliation(s)
- Julie Rodriguez
- INRA, UMR866 Dynamique Musculaire et Métabolisme, Université Montpellier 1, F 34060 Montpellier, France
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18
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Kalista S, Schakman O, Gilson H, Lause P, Demeulder B, Bertrand L, Pende M, Thissen JP. The type 1 insulin-like growth factor receptor (IGF-IR) pathway is mandatory for the follistatin-induced skeletal muscle hypertrophy. Endocrinology 2012; 153:241-53. [PMID: 22087027 DOI: 10.1210/en.2011-1687] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Myostatin inhibition by follistatin (FS) offers a new approach for muscle mass enhancement. The aim of the present study was to characterize the mediators responsible for the FS hypertrophic action on skeletal muscle in male mice. Because IGF-I and IGF-II, two crucial skeletal muscle growth factors, are induced by myostatin inhibition, we assessed their role in FS action. First, we tested whether type 1 IGF receptor (IGF-IR) is required for FS-induced hypertrophy. By using mice expressing a dominant-negative IGF-IR in skeletal muscle, we showed that IGF-IR inhibition blunted by 63% fiber hypertrophy caused by FS. Second, we showed that FS caused the same degree of fiber hypertrophy in wild-type and IGF-II knockout mice. We then tested the role of the signaling molecules stimulated by IGF-IR, in particular the Akt/mammalian target of rapamycin (mTOR)/70-kDa ribosomal protein S6 kinase (S6K) pathway. We investigated whether Akt phosphorylation is required for the FS action. By cotransfecting a dominant-negative form of Akt together with FS, we showed that Akt inhibition reduced by 65% fiber hypertrophy caused by FS. Second, we evaluated the role of mTOR in FS action. Fiber hypertrophy induced by FS was reduced by 36% in rapamycin-treated mice. Finally, because the activity of S6K is increased by FS, we tested its role in FS action. FS caused the same degree of fiber hypertrophy in wild-type and S6K1/2 knockout mice. In conclusion, the IGF-IR/Akt/mTOR pathway plays a critical role in FS-induced muscle hypertrophy. In contrast, induction of IGF-II expression and S6K activity by FS are not required for the hypertrophic action of FS.
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Affiliation(s)
- S Kalista
- Pole of Endocrinology, Diabetes, and Nutrition, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Avenue Hippocrate 55 bte B1.55.06, B-1200 Brussels, Belgium.
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19
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Myostatin: a novel insight into its role in metabolism, signal pathways, and expression regulation. Cell Signal 2011; 23:1441-6. [PMID: 21609762 DOI: 10.1016/j.cellsig.2011.05.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 05/09/2011] [Indexed: 11/24/2022]
Abstract
Myostatin, a member of the transforming growth factor-β (TGF-β) superfamily, is a critical autocrine/paracrine inhibitor of skeletal muscle growth. Since the first observed double-muscling phenotype was reported in myostatin-null animals, a functional role of myostatin has been demonstrated in the control of skeletal muscle development. However, beyond the confines of its traditional role in muscle growth inhibition, myostatin has recently been shown to play an important role in metabolism. During the past several years, it has been well established that Smads are canonical mediators of signals for myostatin from the receptors to the nucleus. However, growing evidence supports the notion that Non-Smad signal pathways also participate in myostatin signaling. Myostatin expression is increased in muscle atrophy and metabolic disorders, suggesting that changes in endogenous expression of myostatin may provide therapeutic benefit for these diseases. MicroRNAs (miRNAs) are a class of non-coding RNAs that negatively regulate gene expression and recent evidence has accumulated supporting a role for miRNAs in the regulation of myostatin expression. This review highlights some of these areas in myostatin research: a novel role in metabolism, signal pathways, and miRNA-mediated expression regulation.
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20
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Dasarathy S, McCullough AJ, Muc S, Schneyer A, Bennett CD, Dodig M, Kalhan SC. Sarcopenia associated with portosystemic shunting is reversed by follistatin. J Hepatol 2011; 54:915-21. [PMID: 21145817 PMCID: PMC3118576 DOI: 10.1016/j.jhep.2010.08.032] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/15/2010] [Accepted: 08/07/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS The distinct role of portosystemic shunting (PSS) in the pathogenesis of sarcopenia (skeletal muscle loss) that occurs commonly in cirrhosis is unclear. We have previously shown increased expression of myostatin (inhibitor of skeletal muscle mass) in the portacaval anastamosis (PCA) rat model of sarcopenia of PSS. The present study was performed to examine the mechanisms of sarcopenia following PCA. METHODS In PCA and sham operated pair fed control rats, the phenylalanine flooding dose method was used to quantify the fractional and absolute protein synthesis rates in the skeletal muscle over time and in response to follistatin, a myostatin antagonist. The expression of myostatin and markers of satellite cell (myocyte precursors) proliferation and differentiation were quantified by real-time PCR and Western blot analyses. RESULTS The absolute synthesis rate (ASR) was lower at 2, 4, and 6 weeks (p<0.05) and the fractional synthesis rate (FSR) of skeletal muscle protein was significantly lower (p<0.05) at week 2 in the PCA rats compared to control rats. Expression of myostatin was elevated while markers of satellite cell proliferation and differentiation were lower at 4 and 6 weeks after PCA. Follistatin increased skeletal muscle mass, muscle FSR and ASR, decreased expression of myostatin protein, and increased expression of markers of satellite cell function. CONCLUSIONS Sarcopenia associated with PSS is caused by impaired protein synthesis and reduced satellite cell function due to increased myostatin expression. Confirming these alterations in human patients with cirrhosis will provide novel therapeutic targets for sarcopenia of liver disease.
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Affiliation(s)
- Srinivasan Dasarathy
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA.
| | - Arthur J. McCullough
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
| | - Sean Muc
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
| | - Alan Schneyer
- Department of Reproductive Biology, Baystate Medical Center, University of Massachusetts, Worcester, Massachusetts, USA
| | - Carole D. Bennett
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
| | - Milan Dodig
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
| | - Satish C. Kalhan
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
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21
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Chan CYX, Masui O, Krakovska O, Belozerov VE, Voisin S, Ghanny S, Chen J, Moyez D, Zhu P, Evans KR, McDermott JC, Siu KWM. Identification of differentially regulated secretome components during skeletal myogenesis. Mol Cell Proteomics 2011; 10:M110.004804. [PMID: 21343469 DOI: 10.1074/mcp.m110.004804] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myogenesis is a well-characterized program of cellular differentiation that is exquisitely sensitive to the extracellular milieu. Systematic characterization of the myogenic secretome (i.e. the ensemble of secreted proteins) is, therefore, warranted for the identification of novel secretome components that regulate both the pluripotency of these progenitor mesenchymal cells, and also their commitment and passage through the differentiation program. Previously, we have successfully identified 26 secreted proteins in the mouse skeletal muscle cell line C2C12 (1). In an effort to attain a more comprehensive picture of the regulation of myogenesis by its extracellular milieu, quantitative profiling employing stable isotope labeling by amino acids in cell culture was implemented in conjunction with two parallel high throughput online reverse phase liquid chromatography-tandem mass spectrometry systems. In summary, 34 secreted proteins were quantified, 30 of which were shown to be differentially expressed during muscle development. Intriguingly, our analysis has revealed several novel up- and down-regulated secretome components that may have critical biological relevance for both the maintenance of pluripotency and the passage of cells through the differentiation program. In particular, the altered regulation of secretome components, including follistatin-like protein-1, osteoglycin, spondin-2, and cytokine-induced apoptosis inhibitor-1, along with constitutively expressed factors, such as fibulin-2, illustrate dynamic changes in the secretome that take place when differentiation to a specific lineage occurs.
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Affiliation(s)
- C Y X'avia Chan
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada
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22
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23
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Lee SJ. Extracellular Regulation of Myostatin: A Molecular Rheostat for Muscle Mass. ACTA ACUST UNITED AC 2010; 10:183-194. [PMID: 21423813 DOI: 10.2174/187152210793663748] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Myostatin (MSTN) is a transforming growth factor-ß family member that plays a critical role in regulating skeletal muscle mass. Genetic studies in multiple species have demonstrated that mutations in the Mstn gene lead to dramatic and widespread increases in muscle mass as a result of a combination of increased fiber numbers and increased fiber sizes. MSTN inhibitors have also been shown to cause significant increases in muscle growth when administered to adult mice. As a result, there has been an extensive effort to understand the mechanisms underlying MSTN regulation and activity with the goal of developing the most effective strategies for targeting this signaling pathway for clinical applications. Here, I review the current state of knowledge regarding the regulation of MSTN extracellularly by binding proteins and discuss the implications of these findings both with respect to the fundamental physiological role that MSTN plays in regulating tissue homeostasis and with respect to the development of therapeutic agents to combat muscle loss.
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Affiliation(s)
- Se-Jin Lee
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, PCTB 803, 725 North Wolfe Street, Baltimore, Maryland 21205, USA
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24
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Cadena SM, Tomkinson KN, Monnell TE, Spaits MS, Kumar R, Underwood KW, Pearsall RS, Lachey JL. Administration of a soluble activin type IIB receptor promotes skeletal muscle growth independent of fiber type. J Appl Physiol (1985) 2010; 109:635-42. [PMID: 20466801 DOI: 10.1152/japplphysiol.00866.2009] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This is the first report that inhibition of negative regulators of skeletal muscle by a soluble form of activin type IIB receptor (ACE-031) increases muscle mass independent of fiber-type expression. This finding is distinct from the effects of selective pharmacological inhibition of myostatin (GDF-8), which predominantly targets type II fibers. In our study 8-wk-old C57BL/6 mice were treated with ACE-031 or vehicle control for 28 days. By the end of treatment, mean body weight of the ACE-031 group was 16% greater than that of the control group, and wet weights of soleus, plantaris, gastrocnemius, and extensor digitorum longus muscles increased by 33, 44, 46 and 26%, respectively (P<0.05). Soleus fiber-type distribution was unchanged with ACE-031 administration, and mean fiber cross-sectional area increased by 22 and 28% (P<0.05) in type I and II fibers, respectively. In the plantaris, a predominantly type II fiber muscle, mean fiber cross-sectional area increased by 57% with ACE-031 treatment. Analysis of myosin heavy chain (MHC) isoform transcripts by real-time PCR indicated no change in transcript levels in the soleus, but a decline in MHC I and IIa in the plantaris. In contrast, electrophoretic separation of total soleus and plantaris protein indicated that there was no change in the proportion of MHC isoforms in either muscle. Thus these data provide optimism that ACE-031 may be a viable therapeutic in the treatment of musculoskeletal diseases. Future studies should be undertaken to confirm that the observed effects are not age dependent or due to the relatively short study duration.
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Affiliation(s)
- Samuel M Cadena
- Acceleron Pharma Inc., 128 Sidney St., Cambridge, MA 02139, USA
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25
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Funkenstein B, Olekh E, Jakowlew SB. Identification of a novel transforming growth factor-beta (TGF-beta6) gene in fish: regulation in skeletal muscle by nutritional state. BMC Mol Biol 2010; 11:37. [PMID: 20459854 PMCID: PMC2881917 DOI: 10.1186/1471-2199-11-37] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 05/12/2010] [Indexed: 12/16/2022] Open
Abstract
Background The transforming growth factor-β (TGF-β) family constitutes of dimeric proteins that regulate the growth, differentiation and metabolism of many cell types, including that of skeletal muscle in mammals. The potential role of TGF-βs in fish muscle growth is not known. Results Here we report the molecular characterization, developmental and tissue expression and regulation by nutritional state of a novel TGF-β gene from a marine fish, the gilthead sea bream Sparus aurata. S. aurata TGF-β6 is encoded by seven exons 361, 164, 133, 111, 181, 154, and 156 bp in length and is translated into a 420-amino acid peptide. The exons are separated by six introns: >643, 415, 93, 1250, 425 and >287 bp in length. Although the gene organization is most similar to mouse and chicken TGF-β2, the deduced amino acid sequence represents a novel TGF-β that is unique to fish that we have named TGF-β6. The molecule has conserved putative functional residues, including a cleavage motif (RXXR) and nine cysteine residues that are characteristic of TGF-β. Semi-quantitative analysis of TGF-β6 expression revealed differential expression in various tissues of adult fish with high levels in skin and muscle, very low levels in liver, and moderate levels in other tissues including brain, eye and pituitary. TGF-β6 is expressed in larvae on day of hatching and increases as development progresses. A fasting period of five days of juvenile fish resulted in increased levels of TGF-β6 expression in white skeletal muscle compared to that in fed fish, which was slightly attenuated by one injection of growth hormone. Conclusion Our findings provide valuable insights about genomic information and nutritional regulation of TGF-β6 which will aid the further investigation of the S. aurata TGF-β6 gene in association with muscle growth. The finding of a novel TGF-β6 molecule, unique to fish, will contribute to the understanding of the evolution of the TGF-β family of cytokines in vertebrates.
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Affiliation(s)
- Bruria Funkenstein
- National Institute of Oceanography, Israel Oceanographic and Limnological Research, Tel Shikmona, POB 8030, Haifa 31080, Israel.
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Vecchione L, Miller J, Byron C, Cooper GM, Barbano T, Cray J, Losee JE, Hamrick MW, Sciote JJ, Mooney MP. Age-related changes in craniofacial morphology in GDF-8 (myostatin)-deficient mice. Anat Rec (Hoboken) 2010; 293:32-41. [PMID: 19899116 DOI: 10.1002/ar.21024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It is well recognized that masticatory muscle function helps determine morphology, although the extent of function on final form is still debated. GDF-8 (myostatin), a transcription factor is a negative regulator of skeletal muscle growth. A recent study has shown that mice homozygous for the myostatin mutation had increased muscle mass and craniofacial dysmorphology in adulthood. However, it is unclear whether such dysmorphology is present at birth. This study examines the onset and relationship between hypermuscularity and craniofacial morphology in neonatal and adult mice with GDF-8 deficiency. Fifteen (8 wild-type and 7 GDF-8 -/-), 1-day-old and 16 (9 wt and 7 GDF-8 -/-), 180-day-old male CD-1 mice were used. Standardized radiographs were taken of each head, scanned, traced, and cephalometric landmarks identified. Significant mean differences were assessed using a group x age, two-way ANOVA. Myostatin-deficient mice had significantly (P < 0.01) smaller body and masseter muscle weights and craniofacial skeletons at 1 day of age and significantly greater body and masseter muscle weights at 180 days of age compared to controls. Myostatin-deficient mice showed significantly (P < 0.001) longer and "rocker-shaped" mandibles and shorter and wider crania compared to controls at 180 days. Significant correlations were noted between masseter muscle weight and all cephalometric measurements in 180-day-old Myostatin-deficient mice. Results suggest that in this mouse model, there may be both early systemic skeletal growth deficiencies and later compensatory changes from hypermuscularity. These findings reiterate the role that masticatory muscle function plays on the ontogeny of the cranial vault, base, and most notably the mandible.
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Affiliation(s)
- Lisa Vecchione
- Pittsburgh Cleft-Craniofacial Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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Li Z, Zhao B, Kim YS, Hu CY, Yang J. Administration of a mutated myostatin propeptide to neonatal mice significantly enhances skeletal muscle growth. Mol Reprod Dev 2010; 77:76-82. [PMID: 19743472 DOI: 10.1002/mrd.21111] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Myostatin is a dominant inhibitor of skeletal muscle development and growth. As transgenic over-expression of myostatin propeptide dramatically enhanced muscle mass, we hypothesized that administration of myostatin propeptide will increase muscle growth. In this study, the wild-type form of porcine myostatin propeptide and its mutated form at the cleavage site of metalloproteinases of BMP-1/TLD family were produced from insect cells. In vitro A204 cells reporter assays showed that both wild-type and the mutated propeptides depressed myostatin activity. The recombinant propeptides at four-fold myostatin concentration can effectively block myostatin function during co-incubation with A204 cells. In particular, the mutated propeptide appeared much more effective than wild-type propeptide over a long period during the in vitro co-incubation. Administration of the mutated propeptide to neonatal mice at the age of 11 and 18 days was tested and showed significant increase in growth performance by 11-15% from the age of 25 to 57 days (P < 0.05). The major skeletal muscles of mice that were injected with mutated propeptide were 13.5-24.8% heavier than the control group (P < 0.05) as a result of muscle fiber hypertrophy. In conclusion, administration of the mutated myostatin propeptide during the neonatal period is an effective way for promoting muscle growth.
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Affiliation(s)
- Zicong Li
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii, Honolulu, Hawaii
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Gilson H, Schakman O, Kalista S, Lause P, Tsuchida K, Thissen JP. Follistatin induces muscle hypertrophy through satellite cell proliferation and inhibition of both myostatin and activin. Am J Physiol Endocrinol Metab 2009; 297:E157-64. [PMID: 19435857 DOI: 10.1152/ajpendo.00193.2009] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Follistatin (FS) inhibits several members of the TGF-beta superfamily, including myostatin (Mstn), a negative regulator of muscle growth. Mstn inhibition by FS represents a potential therapeutic approach of muscle atrophy. The aim of our study was to investigate the mechanisms of the FS-induced muscle hypertrophy. To test the role of satellite cells in the FS effect, we used irradiation to destroy their proliferative capacity. FS overexpression increased the muscle weight by about 37% in control animals, but the increase reached only 20% in irradiated muscle, supporting the role of cell proliferation in the FS-induced hypertrophy. Surprisingly, the muscle hypertrophy caused by FS reached the same magnitude in Mstn-KO as in WT mice, suggesting that Mstn might not be the only ligand of FS involved in the regulation of muscle mass. To assess the role of activin (Act), another FS ligand, in the FS-induced hypertrophy, we electroporated FSI-I, a FS mutant that does not bind Act with high affinity. Whereas FS electroporation increased muscle weight by 32%, the muscle weight gain induced by FSI-I reached only 14%. Furthermore, in Mstn-KO mice, FSI-I overexpression failed to induce hypertrophy, in contrast to FS. Therefore, these results suggest that Act inhibition may contribute to FS-induced hypertrophy. Finally, the role of Act as a regulator of muscle mass was supported by the observation that ActA overexpression induced muscle weight loss (-15%). In conclusion, our results show that satellite cell proliferation and both Mstn and Act inhibition are involved in the FS-induced muscle hypertrophy.
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Affiliation(s)
- Hélène Gilson
- Unité de Diabétologie et Nutrition, Université Catholique de Louvain, 54 Ave. Hippocrate, B-1200, Brussels, Belgium.
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Sumner CJ, Wee CD, Warsing LC, Choe DW, Ng AS, Lutz C, Wagner KR. Inhibition of myostatin does not ameliorate disease features of severe spinal muscular atrophy mice. Hum Mol Genet 2009; 18:3145-52. [PMID: 19477958 DOI: 10.1093/hmg/ddp253] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
There is currently no treatment for the inherited motor neuron disease, spinal muscular atrophy (SMA). Severe SMA causes lower motor neuron loss, impaired myofiber development, profound muscle weakness and early mortality. Myostatin is a transforming growth factor-beta family member that inhibits muscle growth. Loss or blockade of myostatin signaling increases muscle mass and improves muscle strength in mouse models of primary muscle disease and in the motor neuron disease, amyotrophic lateral sclerosis. In this study, we evaluated the effects of blocking myostatin signaling in severe SMA mice (hSMN2/delta7SMN/mSmn(-/-)) by two independent strategies: (i) transgenic overexpression of the myostatin inhibitor follistatin and (ii) post-natal administration of a soluble activin receptor IIB (ActRIIB-Fc). SMA mice overexpressing follistatin showed little increase in muscle mass and no improvement in motor function or survival. SMA mice treated with ActRIIB-Fc showed minimal improvement in motor function, and no extension of survival compared with vehicle-treated mice. Together these results suggest that inhibition of myostatin may not be a promising therapeutic strategy in severe forms of SMA.
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Affiliation(s)
- Charlotte J Sumner
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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Welle S, Burgess K, Mehta S. Stimulation of skeletal muscle myofibrillar protein synthesis, p70 S6 kinase phosphorylation, and ribosomal protein S6 phosphorylation by inhibition of myostatin in mature mice. Am J Physiol Endocrinol Metab 2009; 296:E567-72. [PMID: 19141683 PMCID: PMC2660146 DOI: 10.1152/ajpendo.90862.2008] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Knocking out myostatin activity during development increases the rate of muscle protein synthesis. The present study was done to determine whether postdevelopmental loss of myostatin activity stimulates myofibrillar protein synthesis and the phosphorylation of some of the proteins involved in regulation of protein synthesis rate. Myostatin activity was inhibited for 4 days, in 4- to 5-mo-old male mice, with injections of an anti-myostatin antibody (JA16). The mean myofibrillar synthesis rate increased 19% (P < 0.01) relative to the mean rate in saline-treated mice, as determined by incorporation of deuterium-labeled phenylalanine. JA16 increased phosphorylation of p70 S6 kinase (S6K) and ribosomal protein S6 (rpS6) 1.9-fold (P < 0.05). It did not affect phosphorylation of eukaryotic initiation factor 4E-binding protein-1 or Akt. Microarrays and real-time PCR analyses indicated that JA16 administration did not selectively enrich levels of mRNAs encoding myofibrillar proteins, ribosomal proteins, or translation initiation and elongation factors. Rapamycin treatment did not affect the rate of myofibrillar protein synthesis whether or not the mice received JA16 injections, although it eliminated the phosphorylation of S6K and rpS6. We conclude that the normal level of myostatin activity in mature muscle is sufficient to inhibit myofibrillar synthesis rate and phosphorylation of S6K and rpS6. Reversal of the inhibition of myofibrillar synthesis with an anti-myostatin antibody is not dependent on mTOR activation.
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Affiliation(s)
- Stephen Welle
- University of Rochester Medical Center, Rochester, NY 14642, USA.
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Abstract
PURPOSE OF REVIEW This review reports recent findings on the multiple factors that regulate skeletal muscle growth in neonates. RECENT FINDINGS Skeletal muscle is the fastest growing protein mass in neonates. The high rate of neonatal muscle growth is due to accelerated rates of protein synthesis accompanied by the rapid accumulation of muscle nuclei. Feeding profoundly stimulates muscle protein synthesis in neonates and the response decreases with age. The feeding-induced stimulation of muscle protein synthesis is modulated by enhanced sensitivity to the postprandial rise in insulin and amino acids. Insulin and amino acid signaling components have been identified that are involved in the feeding-induced stimulation of protein synthesis in neonatal muscle. The enhanced activation of these signaling components in skeletal muscle of the neonate contributes to the high rate of muscle protein synthesis and rapid gain in muscle protein mass in neonates. SUMMARY Recent findings suggest that the immature muscle has a heightened capacity to activate signaling cascades that promote translation initiation in response to the postprandial rise in insulin and amino acids thereby enabling their efficient utilization for muscle growth. This capacity is further supported by enhanced satellite cell proliferation, but how these two processes are linked remains to be established.
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Affiliation(s)
- Teresa A Davis
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA.
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Zhang M, Pritchard MR, Middleton FA, Horton JA, Damron TA. Microarray analysis of perichondral and reserve growth plate zones identifies differential gene expressions and signal pathways. Bone 2008; 43:511-20. [PMID: 18579462 PMCID: PMC2569855 DOI: 10.1016/j.bone.2008.04.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2007] [Revised: 04/24/2008] [Accepted: 04/25/2008] [Indexed: 12/23/2022]
Abstract
In the growth plate, the reserve and perichondral zones have been hypothesized to have similar functions, but their exact functions are poorly understood. Our hypothesis was that significant differential gene expression exists between perichondral and reserve chondrocytes that may differentiate the respective functions of these two zones. Normal Sprague-Dawley rat growth plate chondrocytes from the perichondral zone (PC) and reserve zone (RZ) were isolated by laser microdissection and then subjected to microarray analysis. In order to most comprehensively capture the unique features of the two zones, we analyzed both the most highly expressed genes and those that were most significantly different from the proliferative zone (PZ) as a single comparator. Confirmation of the differential expression of selected genes was done by quantitative real-time RT-PCR. A total of 8 transcripts showing high expression unique to the PC included translationally-controlled tumor protein (Tpt1), connective tissue growth factor (Ctgf), mortality factor 4 (Morf4l1), growth arrest specific 6 (Gas6), type V procollagen (Col5a2), frizzled-related protein (Frzb), GDP-dissociation inhibitor 2 (Gdi2) and Jun D proto-oncogene (Jund). In contrast, 8 transcripts showing unique high expression in the RZ included hyaluronan and proteoglycan link protein 1 (Hapln1), hemoglobin beta-2 subunit, type I procollagen (Col1a2), retinoblastoma binding protein 4 (LOC685491), Sparc-related modular calcium binding 2 (Smoc2), and calpastatin (Cast). Other genes were highly expressed in cells from both PC and RZ zones, including collagen II, collagen IX, catenin (cadherin associated protein) beta 1, eukaryotic translation elongation factor, high mobility group, ribosomal protein, microtubule-associated protein, reticulocalbin, thrombospondin, retinoblastoma binding protein, carboxypeptidase E, carnitine palmitoyltransferase 1, cysteine rich glycoprotein, plexin B2 (Plxnb2), and gap junction membrane channel protein. Functional classification of the most highly expressed transcripts were analyzed, and the pathway analysis indicated that ossification, bone remodeling, and cartilage development were uniquely enriched in the PC whereas both the PC and RZ showed pathway enrichment for skeletal development, extracellular matrix structural constituent, proteinaceous extracellular matrix, collagen, extracellular matrix, and extracellular matrix part pathways. We conclude that differential gene expression exists between the RZ and PC chondrocytes and these differentially expressed genes have unique roles to play corresponding to the function of their respective zones.
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Affiliation(s)
- Mingliang Zhang
- Musculoskeletal Sciences Research Laboratory, Department of Orthopedic Surgery, State University of New York Upstate Medical University, Syracuse, New York, 13210
| | - Meredith R. Pritchard
- Musculoskeletal Sciences Research Laboratory, Department of Orthopedic Surgery, State University of New York Upstate Medical University, Syracuse, New York, 13210
| | - Frank A. Middleton
- Microarray Core Facility, Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, 13210
| | - Jason A. Horton
- Musculoskeletal Sciences Research Laboratory, Department of Orthopedic Surgery, State University of New York Upstate Medical University, Syracuse, New York, 13210
| | - Timothy A. Damron
- Musculoskeletal Sciences Research Laboratory, Department of Orthopedic Surgery, State University of New York Upstate Medical University, Syracuse, New York, 13210
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Yang X, Yang C, Farberman A, Rideout TC, de Lange CFM, France J, Fan MZ. The mammalian target of rapamycin-signaling pathway in regulating metabolism and growth1,2. J Anim Sci 2008; 86:E36-50. [DOI: 10.2527/jas.2007-0567] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Anderson BC, Christiansen SP, McLoon LK. Myogenic growth factors can decrease extraocular muscle force generation: a potential biological approach to the treatment of strabismus. Invest Ophthalmol Vis Sci 2008; 49:221-9. [PMID: 18172096 DOI: 10.1167/iovs.07-0600] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Future pharmacologic treatment of strabismus may be optimized if drugs that are less potentially toxic to patients can be developed. Prior studies have shown that direct injection of extraocular muscles (EOMs) with insulin growth factor or fibroblast growth factor results in significant increases in the generation of EOM force. The purpose of this study was to examine the morphometric and physiological effects of direct EOM injection with the growth factors BMP4, TGFbeta1, Shh, and Wnt3A. METHODS One superior rectus muscle of normal adult rabbits was injected with BMP4, TGFbeta1, Shh, or Wnt3A. The contralateral muscle was injected with an equal volume of saline to serve as a control. After 1 week, the animals were euthanatized, and both superior rectus muscles were removed and assayed physiologically. The muscles were stimulated at increasing frequencies to determine force generation. A separate group of treated and control superior rectus muscles were examined histologically for alterations in total muscle cross-sectional area and myosin heavy chain isoform (MyHC) composition. RESULTS One week after a single injection of BMP4, TGFbeta1, Shh, or Wnt3A, all treated muscles showed significant decreases in generation of force compared with control muscles. BMP4, TGFbeta1, Shh, and Wnt3A significantly decreased the mean myofiber cross-sectional area of fast MyHC-positive myofibers. BMP4 resulted in a conversion of fast-to-slow myofibers and a significant decrease in the percentage of developmental and neonatal MyHC-positive myofibers. Alterations in mean cross-sectional area and proportion of MyHCs were seen after injection with TGFbeta1, Shh, and Wnt3A. TGFbeta1 and BMP4 injections resulted in increased Pax7-positive satellite cells, whereas BMP4, TGFbeta1, and Wnt3A resulted in a decrease in MyoD-positive satellite cells. CONCLUSIONS These results suggest that, rather than using toxins or immunotoxins, a more biological approach to decrease muscle strength is possible and demonstrate the potential utility of myogenic signaling factors for decreasing EOM strength. Ongoing drug-delivery studies will elucidate means of extending treatment effect to make such agents clinically useful.
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Affiliation(s)
- Brian C Anderson
- Department of Ophthalmology, University of Minnesota, 2001 6th Street SE, Minneapolis, MN 55455, USA
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McGee SL, Mustard KJ, Hardie DG, Baar K. Normal hypertrophy accompanied by phosphoryation and activation of AMP-activated protein kinase alpha1 following overload in LKB1 knockout mice. J Physiol 2008; 586:1731-41. [PMID: 18202101 DOI: 10.1113/jphysiol.2007.143685] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The activation of the AMP-activated protein kinase (AMPK) and inhibition of the mammalian target of rapamycin complex 1 (mTORC1) is hypothesized to underlie the fact that muscle growth following resistance exercise is decreased by concurrent endurance exercise. To directly test this hypothesis, the capacity for muscle growth was determined in mice lacking the primary upstream kinase for AMPK in skeletal muscle, LKB1. Following either 1 or 4 weeks of overload, there was no difference in muscle growth between the wild type (wt) and LKB1(-/-) mice (1 week: wt, 38.8 +/- 7.75%; LKB1(-/-), 27.8 +/- 12.98%; 4 week: wt, 75.8 +/- 15.2%; LKB1(-/-), 85.0 +/- 22.6%). In spite of the fact that the LKB1 had been knocked out in skeletal muscle, the phosphorylation and activity of the alpha1 isoform of AMPK were markedly increased in both the wt and the LKB1(-/-) mice. To identify the upstream kinase(s) responsible, we studied potential upstream kinases other than LKB1. The activity of both Ca(2+)-calmodulin-dependent protein kinase kinase alpha (CaMKKalpha) (5.05 +/- 0.86-fold) and CaMKKbeta (10.1 +/- 2.59-fold) increased in the overloaded muscles, and this correlated with their increased expression. Phosphorylation of TAK-1 also increased 10-fold following overload in both the wt and LKB1 mice. Even though the alpha1 isoform of AMPK was activated by overload, there were no increases in expression of mitochondrial proteins or GLUT4, indicating that the alpha1 isoform is not involved in these metabolic adaptations. The phosphorylation of TSC2, an upstream regulator of the TORC1 pathway, at the AMPK site (Ser1345) was increased in response to overload, and this was not affected by LKB1 deficiency. Taken together, these data suggest that the alpha1 isoform of AMPK is preferentially activated in skeletal muscle following overload in the absence of metabolic adaptations, suggesting that this isoform might be important in the regulation of growth but not metabolism.
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Affiliation(s)
- Sean L McGee
- Functional Molecular Biology Lab, Division of Molecular Physiology, University of Dundee, Sir James Black Centre, Dow Street, Dundee DD1 5EH, UK
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Baoutina A, Alexander IE, Rasko JEJ, Emslie KR. Potential Use of Gene Transfer in Athletic Performance Enhancement. Mol Ther 2007; 15:1751-66. [PMID: 17680029 DOI: 10.1038/sj.mt.6300278] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
After only a short history of three decades from concept to practice, gene therapy has recently been shown to have potential to treat serious human diseases. Despite this success, gene therapy remains in the realm of experimental medicine, and much additional preclinical and clinical study will be necessary for proving the efficacy and safety of this approach in the treatment of diseases in humans. However, a potential complicating factor is that advances in gene transfer technology could be misused to enhance athletic performance in sports, in a practice termed "gene doping". Moreover, gene doping could be a precursor to a broader controversial agenda of human "genetic enhancement" with the potential for a significant long-term impact on society. This review addresses the possible ways in which knowledge and experience gained in gene therapy in animals and humans may be abused for enhancing sporting prowess. We provide an overview of recent progress in gene therapy, with potential application to gene doping and with the major focus on candidate performance-enhancement genes. We also discuss the current status of preclinical studies and of clinical trials that use these genes for therapeutic purposes. Current knowledge about the association between the natural "genetic make-up" of humans and their physical characteristics and performance potential is also presented. We address issues associated with the safety of gene transfer technologies in humans, especially when used outside a strictly controlled clinical setting, and the obstacles to translating gene transfer strategies from animal studies to humans. We also address the need for development and implementation of measures to prevent abuse of gene transfer technologies, and to pursue research on strategies for its detection in order to discourage this malpractice among athletes.
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Affiliation(s)
- Anna Baoutina
- National Measurement Institute, Pymble, New South Wales, Australia.
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Molecular cloning of the Atlantic salmon activin receptor IIB cDNA - Localization of the receptor and myostatin in vivo and in vitro in muscle cells. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2007; 2:101-11. [PMID: 20483283 DOI: 10.1016/j.cbd.2006.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Revised: 11/01/2006] [Accepted: 12/31/2006] [Indexed: 11/22/2022]
Abstract
In mammals, the activin receptor type IIB (ActRIIB) binds with high affinity several members of the transforming growth factor-beta (TGF-beta) superfamily, including the negative muscle regulator myostatin (MSTN). In this study, an actRIIB cDNA of 1443 bp was isolated by reverse transcription (RT)-PCR from the liver of Atlantic salmon (Salmo salar) encoding almost the complete receptor. The deduced salmon ActRIIB of 481 amino acids (aa) contained the conserved catalytic domain of serine/threonine protein kinases, and showed the highest sequence identity (83-87%) to the zebrafish, chicken and goldfish ActRIIB. Salmon actRIIB mRNA was identified by RT-PCR in all the examined tissues of juvenile fish that was confirmed by in situ hybridization. In comparison, the salmon MSTN signal was less widespread, and co-expression of the receptor and this putative ligand was only demonstrated in skeletal muscle. Consistently, both ActRIIB and MSTN were immunocytologically identified in salmon myoblasts and differentiated myotubes in culture.
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